AADCO 737-5 AND 737-10 PURE AIR GENERATORS

OPERATING INSTRUCTIONS
AADCO 737-SERIES
PURE AIR GENERATORS
737-5 737-10
(5-lpm)
(10-lpm)
AADCO INSTRUMENTS, INC.
145 South Miami Ave.
Village of Cleves, OH 45002
Telephone: (513) 467-1477
Fax: (513) 467-9009
ii
AADCO 737-5 AND 737-10 PURE AIR GENERATORS
TABLE OF CONTENTS
Section
Page
LIST OF ILLUSTRATIONS .......................................................................... iii
0.0
DAMAGED AND/OR LOSS IN SHIPMENT PROCEDURE .......................... 1
1.0
INSTALLATION ............................................................................................ 2
2.0
REAR PANEL CONNECTIONS .................................................................... 4
3.0
OPERATIONAL TEST .................................................................................. 5
4.0
OPERATIONAL PROCEDURES .................................................................. 7
5.0
PRINCIPLE OF OPERATION ..................................................................... 10
6.0
BALLAST TANK AND BALLAST BLEED SYSTEM .................................... 12
7.0
COMPRESSOR UNIT................................................................................. 13
8.0
COMPRESSOR CONTROL SYSTEM ........................................................ 14
9.0
PURIFICATION REACTORS ...................................................................... 16
10.0
METHANE REACTORS ............................................................................. 18
11.0
PERFORMANCE SPECIFICATIONS ......................................................... 20
12.0
PREVENTIVE MAINTENANCE .................................................................. 22
13.0
TROUBLE SHOOTING ............................................................................... 23
14.0
PRESSURE SWITCH ADJUSTMENT ........................................................ 32
15.0
COMPONENT REPLACEMENT ................................................................. 34
16.0
737-104 AUTO PURE AIR MANIFOLD ...................................................... 36
17.0
737-105 AUTO SOURCE SELECTOR ....................................................... 37
18.0
PARTS LIST ............................................................................................... 38
ILLUSTRATIONS ...................................................................... 40 through 62
WARRANTY ............................................................................................... 63
iii
AADCO 737-5 AND 737-10 PURE AIR GENERATORS
LIST OF ILLUSTRATIONS
Figure
Page
1
GENERATOR & SILENCER HOUSING, REAR VIEW .......................................... 40
2
GENERATOR & SILENCER HOUSING, FRONT VIEW ....................................... 41
3
GENERATOR WITH “HOUSE” AIR ADAPTER .................................................... 42
4
GENERATOR, FRONT PANEL ............................................................................ 43
5
GENERATOR, INTERNAL VIEW, RIGHT SIDE ................................................... 44
6
GENERATOR, INTERNAL VIEW, LEFT SIDE...................................................... 45
7
GENERATOR WITH METHANE REACTOR & MIXER-RECEIVERS
OPERATING FROM EXTERNAL SOURCE, NO COMPRESSOR ..................... 46
7a
GENERATOR, AS FIGURE 7, OPPOSITE VIEW ................................................. 47
8
COMPRESSOR SILENCER HOUSING, INTERNAL VIEW .................................. 48
9
BALLAST TANK WITH MANUAL BLEED ............................................................. 49
10
FREE STANDING METHANE REACTOR ............................................................ 50
11
GENERATOR WITH AUTO SOURCE MANIFOLD ............................................... 51
11b
GENERATOR WITH PURE AIR MANIFOLD ........................................................ 52
11c
AUTO PURE AIR MANIFOLD & AUTO SOURCE SELECTOR ............................ 53
12
GC ANALYSIS FOR CO2, “C” PURIFICATION REACTOR .................................. 54
13
CO2 OUTPUT FROM “A” VS “C” PURIFICATION REACTOR .............................. 55
14
MOISTURE VS TIME NOMOGRAPHS ................................................................ 56
15
FID RESPONSE CYLINDER AIR VS “B” PURIFICATION REACTOR .................. 57
16
EFFICIENCY OF THE METHANE REACTOR ...................................................... 58
17
PNEUMATIC DIAGRAM ....................................................................................... 59
18
WIRING DIAGRAM .............................................................................................. 60
19
737-5 ROTAMETER FLOW NOMOGRAPH ......................................................... 61
iv
20
737-10 ROTAMETER FLOW NOMOGRAPH ....................................................... 62
v
0.0
DAMAGED AND/OR LOST IN SHIPMENT PROCEDURE
0.1
SHIPMENTS FOB FACTORY. This shipment was thoroughly inspected before it
was delivered to the carrier. Our responsibility for this shipment has now ended.
Therefore, a thorough inspection of the contents should be made upon its arrival.
0.2
In the event any portion of the shipment is damaged or missing, do not sign the
bill of lading or express receipt until the freight or express agent makes
appropriate notation on the receipt.
0.3
Concealed damage means damage which may not be apparent until after the
items are unpacked and tested. In case of concealed damage, a written request
for inspection should be filed with the carrier within 15 days of the delivery date.
Delay in making this request may provide grounds for refusal of your claim. Be
certain to retain the carbon, packing materials, wrappings, etc., until the carrier
has made his inspection. Keep in mind that concealed damage can occur from
rough handling even though the cartons show no evidence of external damage.
0.4
The carrier may request return of the damaged item to us for inspection and
repair. In this event, we will repair or replace the item and invoice you for the
costs involved. This invoice then becomes part of your claim upon the carrier.
0.5
SHIPMENTS FOB DESTINATION. In the case of damage in transit on
shipments made FOB Destination, we will gladly handle filing of the claim,
provided an acceptable inspection report from the carrier is furnished to us. In
the event that our claim is disallowed because of your negligence in obtaining the
report, it will be necessary to bill you for the repair or replacement charges.
0.6
RETURN TO ADDCO INSTRUMENTS, INC. If your property, while being
returned to AADCO Instruments, Inc., is damaged in transit, it will be your
responsibility to file a claim with the carrier. To assist you we will secure an
inspection report from the carrier and forward it to you.
0.7
Prior to shipment to AADCO Instruments, Inc. You should call or write notifying
us of your intent. You must include some identifying note or letter with the item.
This note should include the name of your factory contact and the nature of the
damage.
1
1.0
INSTALLATION.
1.1
Before attempting installation, it should be borne in mind that the performance of
the pure air generator hinges upon the availability of a large volume of
pressurized air in close proximity to the instrument. THIS IS MANDATORY. If
the air source is unable to satisfy the sudden demands for pressurized air, the
pure air generator will NOT perform to specifications.
1.2
AADCO Instruments, Inc. supplies pure air generators with or without air
compressor, depending upon availability of compressed air at the user’s site. If
“plant” air is available, follow the procedure outlined for installation WITHOUT
COMPRESSOR (Sections 1.6 through 1.8), otherwise use the WITH
COMPRESSOR procedure (Sections 1.9 through 1.12).
1.3
If initial visual inspection reveals no damage after unpacking, remove all shipping
plugs from the bulkhead fittings on the rear of the instrument. Should there be
any indications of damage, see Section 0.0 for instructions. If further information
is required, consult the factory.
1.4
Locate the unit in an area which will permit a free flow of air, avoiding confined
spaces. This is especially important if the unit houses a methane reactor system.
The heat generated during operation of the methane reactor must be dissipated
away from the instrument. If the unit does not contain a methane reactor,
location is not critical. However, it should be kept away from the wall.
1.5
It is not unusual to situate these instruments on specially constructed shelves
above head level, in out of the way places outside the area of use; e.g., in
hallways, electrical rooms, etc.
1.6
For INSTALLATION WITHOUT COMPRESSOR, using a “plant” or “house” air
source, locate the unit as in Section 1.4. Install the “house” air adapter, Figure 3
(54), being certain that the connection to the EXTERNAL SOURCE fitting,
Figure 3 (57), is tight. Connect the air supply to the inlet fitting of the “house” air
adapter, Figure 3 (56). Close the water drain valve, Figure 3 (55), finger tight.
NOTE:
Inlet air pressure cannot exceed 100-psig nor be less than 70-psig.
1.7
Install the power cord into a suitable electrical outlet.
1.8
Admit the source air into the “house” air adapter. The INPUT PRESSURE
gauge, Figure 4 (3), should indicate the pressure of the air source. Leak check
all incoming air connections with soap solution and remedy as needed. The unit
is now ready for operation.
2
1.9
For INSTALLATION WITH COMPRESSOR, place the compressor assembly,
Figures 1 and 2 (50), between two level surfaces so that the underside of the
assembly is exposed. DO NOT INVERT. Remove the two red shipping bolts
located on the underside and retain for future use.
1.10
Place the generator unit and compressor unit side by side as shown in Figures 1
and 2, with the compressor unit, Figures 1 and 2 (50), left of the generator unit as
shown. Place the ballast tank Figures 1 and 9 (16), on top of the compressor
unit and install the curved metal tubing which is supplied and labeled, Figure 2
(53), between the compressor outlet fitting and the check valve on the ballast
tank, Figures 1, 2 and 9 (24).
1.11
Install the ¼-inch o.d. plastic tubing, Figure 1 (51), supplied between the outlet
fitting on top of the ballast tank and the PUMP fitting, Figure 1 (58), on the rear of
the generator unit. Lastly, install the dump muffler in the DUMP fitting Figure 1
(60) and direct downward.
1.12
Connect the compressor power cord into the AUX POWER outlet on the lower
rear of the generator unit, as shown in Figure 1. Once the six-foot power cord
has been inserted into the proper electrical outlet, the unit is ready for operation.
3
2.0
REAR PANEL CONNECTIONS.
2.1
The DUMP bulkhead connection, Figure 1 (60), is the outlet for air containing
those impurities removed from the unclean feed air. It is vented outside the
instrument cabinet to prevent deposition of water and other materials within the
instrument. The DUMP connection also provides a suitable connection for
sample collection of the impurity concentrate which elutes from this port.
2.2
The DUMP port must NOT be closed or impeded by any restriction which would
produce back pressure at this point.
2.3
The PUMP bulkhead fitting, Figure 1 (58), is a standard ¼-inch swage
connection. Care should be taken that the air supply tubing is kink-free as in
Figure 1.
2.4
The PURE AIR bulkhead connector, Figure 1 (59), is the pure air outlet from the
pure air generator. It will accept ¼-inch swage type connectors.
NOTE:
Particulate filters are neither required nor recommended.
2.5
The AUXILIARY POWER outlet, Figure 1, provides power to the compressor
through the PUMP switch, Figure 4 (1).
2.6
Those units supplied for connection to “house” air, as in Figure 3, are shipped
without PUMP switch, fuseholder, and AUXILIARY POWER outlet.
4
3.0
OPERATIONAL TEST.
3.1
DO NOT CONNECT ANY EQUIPMENT TO THE PURE AIR GENERATOR
SYSTEM AT THIS TIME.
3.2
After making all electrical and pneumatic connections to both generator and
compressor units according to instructions attached to each unit and as
shown in the appropriate figures, the system is ready for operation.
3.3
IF INSTALLATION HAS BEEN COMPLETED AS SHOWN IN FIGURES 1 and
2 WHEREBY THE PURE AIR GENERATOR USES AN AADCO
COMPRESSOR, REFERENCE FIGURE 4 FOR THE FOLLOWING
OPERATIONS.
3.4
Depress the PUMP switch (1) on the generator unit by depressing the lamp
itself. The compressor should start and the indicator lamp within the PUMP
switch should light. Within a short time there should be indication of increasing
input pressure as noted on the INPUT PRESSURE gauge (3).
NOTE:
The compressor will not start at this time if any pressure greater than
60-psig appears on the INPUT PRESSURE gauge.
3.5
At this time, the tubing leading from the compressor unit to the ballast tank and
to the generator unit should be checked for leaks by applying a soap solution to
all of the connections and tightening as required.
3.6
When the input pressure reaches 80-psig as evidenced on the INPUT
PRESSURE gauge, the compressor will cease to operate. The input pressure
at this time will remain constant at 80-psig.
NOTE:
3.7
Checking for leaks when the compressor is not operating will be
pointless since the connecting hoses between the compressor and
generator will not be pressurized. This check can be made only
when the compressor is running.
Depress the power switch (2) by depressing the lamp itself. The indicator lamp
within the switch will light. The METHANE HEAT lamp (4) will light if there is a
methane reactor within the unit. There should be an audible “click” of the
solenoid valve on the purification reactor followed immediately by a momentary
decrease of the input pressure. This is the initial pressurization of one side of
the purification reactor. There may also be a rise in the output pressure, as
evidenced on the OUTPUT PRESSURE gauge (6), if the OUTPUT PRESSURE
REGULATOR (5) had been set previously to some pressure. In addition, the
cooling fan on the inside rear wall of the generator should operate, Figures 5
5
3.8
and 6 (28).
Wait at least one minute to allow both sides of the purification reactor to
pressure up and then adjust the output pressure to any desired pressure up to
50-psig with the OUTPUT PRESSURE REGULATOR. This output pressure
will be observed on the OUTPUT PRESSURE gauge (6).
3.9
Output flow should be adjusted via the OUTPUT FLOW ADJUST valve (13) to
some value between zero and 10.0 on the rotameter (10).
3.10
After about one-half hour of operation the METHANE HEAT lamp (4), if
present, should cycle, indicating that a maximum temperature has been
reached and is being maintained. During this half-hour “burn-in”, copious
amounts of water will exit from the PURE AIR FITTING, Figure 1 (59), on the
rear of the generator unit. It is advantageous to attach temporarily a short (six
to twelve-inch by ¼-inch o.d.) length of plastic tubing to that fitting to permit the
exiting water to clear the hoses and power cords of the unit.
3.11
The METHANE HEAT pyrometer (7) should indicate 290C ± 10C. If a
temperature other than this is observed, refer to Section 13.22, Methane
Reactor, for remedial action.
3.12
During the entire interval, from start up to full maximum temperature of the
methane reactor, the input pressure should be cycling between 60 and 80-psig
indicating that the pressure switch is operating properly. If not, consult Section
14.0, Pressure Switch Adjustment.
3.13
If all operations have been followed according to Sections 3.4 through 3.11,
allow the system to operate for several hours to permit maximum elimination of
the “burn-in” water. See Figure 14 for moisture versus time for both purification
and methane reactors.
3.14
IF INSTALLATION HAS BEEN COMPLETED AS SHOWN IN FIGURE 3
WHEREBY THE PURE AIR GENERATOR USES “HOUSE” AIR FOR ITS AIR
SOURCE, OBSERVE THE FOLLOWING OPERATIONS.
3.15
Admit the source air into the pure air generator. The INPUT PRESSURE
gauge, Figure 4 (3), should indicate the pressure of the source air.
NOTE:
This pressure must not be less than 60-psig nor greater than 100psig. If the input pressure is less than 60-psig the quality of the air
produced by the pure air generator will be jeopardized. If the
pressure is greater than 100-psig the unit may malfunction since the
components are not rated greater than 100-psig.
6
3.16
Follow the procedures as outlined in Section 3.7 through Section 3.13.
7
4.0
OPERATIONAL PROCEDURES.
4.1
Once all connections and checkouts have been completed as in Sections 3.0
through 3.13, the pure air generator system is ready for connection to the
equipment that is to receive the zero air. Connections must be made with ¼inch o.d. thin-walled tubing with the using equipment located as close to the
pure air generator as possible. One-eighth inch o.d. tubing or small bore ¼inch tubing should be avoided because of the back pressure exerted on the
system by the restrictive tubing.
4.2
If connection fittings at the using equipment are _-inch swage type, use ¼-inch
large bore tubing from the pure air generator to the using equipment and then
reduce to _-inch tubing, keeping the _-inch length as short as possible. All
“tee’s” should be ¼-inch also.
4.3
After completing all plumbing connections, close all needle valves and flow
control devices at the using equipment and open the OUTPUT FLOW ADJUST
valve, Figure 4 (13), completely counter clockwise so that there is NO flow at
the using equipment. The rotameter ball on the pure air generator should drop
to zero indicating that the system is leak tight. If not, check for leaks at all
connections with soap solution and tighten all loose connections until the
rotameter ball does drop to zero. It is imperative that all leaks are detected and
remedied before putting the system into full operation.
4.4
To determine the proper output pressure from the pure air generator,
ascertaining the greatest pressure required by any or all of the instruments is
necessary. For example, if there are five instruments and the highest pressure
required for any one or all of the instruments is 30-psig, then the output
pressure of the pure air generator can be set no lower than 40-psig. This 10psig pressure differential is mandatory for proper operation of any differential
pressure regulator. The 40-psig accommodates not only that instrument with
the 30-psig requirement but all of the others as well.
4.5
If the instruments connected to the pure air generator do NOT have their own
pressure regulators but, instead, have a mandated input pressure at which the
instruments are to function optimally, then it is the responsibility of the operator
to install separate pressure regulators after the generator, in the line, for each
instrument. AADCO Instruments offers in-line pressure regulators for this
purpose (part no. 20033).
4.6
There are two pressure conditions for operating the pure air generator.
8
4.7
The first pressure condition is when the output is permitted to enter an ambient
pressure environment; i.e., wherein the effluent enters and purges an
environmental chamber; or passes into a sampling manifold which itself vents
to the atmosphere, etc. In each case there will be no back pressure exerted
upon the pure air generator.
4.8
In this “no back pressure” situation, the output flow is controlled by the
OUTPUT FLOW ADJUST knob, Figure 4 (13), and the flow reading is taken
from the rotameter, Figure 4 (10), in millimeters and compared with the
applicable nomograph, Figure 19 or 20, for actual flow in liters per minute.
4.9
The second pressure condition is when the pure air generator is connected to
external equipment and the OUTPUT FLOW ADJUST valve is opened counter
clockwise, permitting full flow through the valve. Flow control in this situation is
performed at the external equipment through is flow control system. In this
instance, the pure air generator is operating in a “back pressure” mode, placing
the rotameter under pressure and no longer allowing the rotameter to be direct
reading.
4.10
The pressure under which the rotameter is operating is determined by the
operator when setting the output pressure with the OUTPUT PRESSURE
REGULATOR, Figure 4 (5). This pressure setting will greatly influence the
relationship between the observed flow on the rotameter and the actual flow.
4.11
The formula for determining actual flow is N+1 x R.
N = Output pressure in atmospheres (14.7 psi = 1 atmosphere).
R = Rotameter reading in LPM (NOT millimeters).
4.12
You can readily see that at 45-psig output pressure the indicated flow at the
rotameter will be exactly one-half the actual flow and you must multiply the
rotameter readings at this pressure (45-psig) by TWO to determine the actual
flow.
4.13
For the operator’s convenience, listed in Section 4.14 are the multiplier for each
output pressure setting. Simply multiply the rotameter reading in LPM
(determined by the proper nomograph, Figure 19 or 20) using the multiplier
from the listing for that operating pressure.
9
4.14
OUTPUT PRESSURE
60
55
50
45
40
35
30
25
20
15
10
5
MULTIPLIER
2.24
2.16
2.08
2.00
1.91
1.82
1.73
1.63
1.53
1.415
1.29
1.155
4.15
The purpose of this exercise is to allow the operator to know his flow conditions
but, more importantly, TO AVOID EXCEEDING THE OUTPUT CAPACITY OF
THE PURE AIR GENERATOR AND JEOPARDIZING THE OUTPUT PURITY.
Each pure air generator has a maximum output rating and the operator should
know this before setting flows.
4.16
Any instrument that is sensitive to even slight variations in oxygen
concentration; i.e., flame ionization detectors used with total hydrocarbon
analyzers, gas chromatographs, flame photometric detectors, etc., all require
incorporation of mixer-receivers, Figure 7 (49), in the pure air generator system
for homogenization of the air mixture before use by the above-mentioned
detectors. NDIR, chemiluminescent, photoionization, and electrochemical
sensors are unaffected by slight variations in oxygen concentration and,
therefore, do not require mixer-receivers. See Section 18, Parts List, for
appropriate models.
4.17
SHUTDOWN PROCEDURE.
4.18
If the unit is not to be used for one week or more, depress the PUMP switch,
Figure 4 (1), depress the POWER switch, Figure 4 (2), and immediately cap
both the PURE AIR outlet, Figures 1 and 3 (59), and the DUMP fitting, Figures
1 and 3 (60), to avoid contaminants from entering the system.
10
5.0
PRINCIPLE OF OPERATION (REFERENCE FIGURE 17).
5.1
The 737-series pure air generators produce absolutely clean air from
pressurized unclean air by chromatographic techniques. Pressurized air from a
compressor or other source enters the number one or number two column
system, depending upon the status of the solenoid valve located at the inlet of
the column. These valves (S-1 and S-2) are normally closed so that when the
POWER switch is off the inlets to the columns are closed, sealing the system
against possible contamination.
5.2
The pressurized air passes through the column where selective adsorption
takes place, with a subsequent separation of the various components present
in the air. Only the desired components, which elute first, are permitted to
reach the end of the column system and elute, whereupon the solenoid valve at
the head of the separation column closes and the solenoid valve at the inlet to
the alternate column systems opens.
5.3
Pressurized unclean air now enters the alternate column system where
separation again takes place. The alternation of the two column systems
produces a steady flow of purified air.
5.4
During the interval that pressurized unclean air is being separated in one
column, a portion of the clean air passes through the purge valve and
backflushes the alternate column of impurities. This purge valve, Figures 5 and
6 (19), has been set at the factory for optimum flow and MUST NOT BE
ALTERED.
5.5
The backflush flow of air with impurities exits from the instrument through the
swage bulkhead connector labeled DUMP at the rear of the instrument, Figure
1 (60). THIS EXIT MUST NOT BE RESTRICTED. A back pressure situation
must be avoided at this fitting.
5.6
The timer, which provides alternate power to the solenoid valves, has been set
to effect the proper residence time of the unclean air in the columns and also
the purge time for each size reactor.
5.7
To prolong the life of the support media within the columns, it is mandatory that
the operational directions for the instrument be followed as closely as possible.
Selection of this separation media, residence time in the column, proper input
pressures, purge flows, and column volumes have been determined to meet
the requirements of the particular 737-series pure air generator being used.
These components are NOT interchangeable except among units of the same
rated output.
11
5.8
Damage to the purification reactor can occur if: (a) improperly filtered air is
admitted to the columns as with oil compressors, (b) water is admitted to
columns due to oversight on the operator’s part in failing to drain the ballast
tank and allowing water to carry over, (c) the unit is operated above its rated
capacity, or (d) the input pressure requirements are not met. See Section 3.15.
12
6.0
BALLAST TANK AND BALLAST BLEED SYSTEM
6.1
The ballast tank, Figures 1, 2 and 9 (16), is placed in the system after the
compressor, prior to and in close proximity to the purification reactor, to serve
as a reservoir for the pressurized input air. Each tank has been carefully sized
for the rated capacity of its pure air generator.
6.2
When the solenoid valve at the inlet to the column opens, a requirement for a
rapid supply of pressurized air develops. The compressor alone would be
unable to satisfy this requirement within a reasonable amount of time and
would cause great variations in the input pressure and improper separations
within the purification reactor, resulting in variations in output pressure and flow
as well as a deterioration in purity. The pressurized volume within the ballast
tank, located immediately adjacent to the columns, provides an instant
response to this need.
6.3
Because the ballast tank is so critical to the operation of the system, care must
be taken to ensure there will be no decrease in its volume. Volume loss occurs
only when water from the input compressed air is permitted to collect in the
tank.
6.4
AADCO Instruments, Inc. supplies an internally-coated, rust-proof ballast tank
with each system which is equipped with a manual toggle valve, Figures 1, 2
and 9 (12), for bleeding the coalesced water from the tank.
6.5
The manual toggle valve system is a simple toggle valve located on the ballast
tank. This valve should be opened at least once every three days while the
system is operating and the ballast tank is pressurized. The air pressure within
the tank forces the accumulated water to the toggle BALLAST BLEED valve.
During periods of high humidity, a once per day bleed would be required.
6.6
The operator is manually able to determine the condition of the ballast tank by
opening the toggle valve at any time. There should be a sharp flow of
pressurized air with water from the tubing. If not, there is blockage which
should be cleared.
13
7.0
COMPRESSOR UNIT.
7.1
A compressor, Figure 8 (43), contained is a separate sound-proofed assembly,
provides compressed air to the pure air generator. Each compressor is sized
for a particular generator system. When replacement is necessary, it should be
replaced with the same size compressor with the same voltage requirements.
7.2
The compressor is shock-isolated from the cabinet proper by four springs and a
special mounting plate, Figure 8 (46).
7.3
Operating air and cooling air are both admitted at the front bottom of the unit,
passing through a sound baffle system, and into the compressor chamber.
Care must be taken to avoid obstructing both the incoming air and the hot air
exiting from the cabinet. See Section 1.4.
7.4
Hot air is removed from the cabinet by a high volume fan, Figure 8 (45),
mounted on a vertical duct within the compressor cabinet. Failure of the fan will
cause the compressor to stop operating, even though power is applied,
because of increased temperature within the compressor chamber. A thermal
switch, located within the compressor motor, performs this operation. This
switch is both non-adjustable and inaccessible.
7.5
In addition to the duct-mounted cooling fan, a second fan is attached to the
drive shaft of the compressor itself. This fan is located directly beneath the
louvered shroud on the front end of the compressor and is press-fit on the drive
shaft.
7.6
Compressor replacement is dictated by its inability to supply compressed air at
the desired rate and/or pressure. See Section 12.5 for diagnostic procedures
and Section 13.1 for service.
14
8.0
COMPRESSOR CONTROL SYSTEM
(SEE FIGURE 17 FOR PNEUMATIC REFERENCE
AND FIGURE 18 FOR ELECTRICAL REFERENCE.)
8.1
A combination pressure switch/pressure relief valve system is installed in all
AADCO pure air generators with output volumes greater than 1-LPM but less
than 50-LPM.
8.2
The purpose of this system is to permit the compressor to operate intermittently
rather than continuously. The compressor will turn on at 60-psig or less and off
at 80-psig.
Operating the compressor in this manner greatly reduces
compressor wear and promotes cooler operation, both of which extend its
lifespan.
8.3
During operation the ballast tank, Figures 1, 2 and 9 (16), serves as the
pressure reference for the system. The pressure switch, Figures 5 and 6 (17),
serves as the sensor and the check valve, Figures 1, 2 and 9 (24), confines the
pressurized air within the ballast tank once the compressor has turned off.
8.4
The pressure switch is a normally closed switch, closing at 60-psig or less and
opening at 80-psig. This switch controls the coil of the solid state relay, Figures
5 and 6 (21), which in turn supplies power to the compressor through the AUX
POWER outlet, Figure 1.
8.5
Any low pressure condition (60-psig or less) within the ballast tank produces a
closed switch condition at the pressure switch. This in turn causes power to be
supplied to the compressor via the solid state relay, Figures 5, 6 and 11 (21),
and the AUX POWER outlet.
8.6
At 80-psig the pressure switch opens, removing power from the coil of the solid
state relay, which in turn removes power from the compressor.
8.7
The compressor pressure relief valve, Figure 8 (23), (a normally closed threeway valve) is wired in parallel with the power to the compressor at the AUX
POWER outlet. When power is removed from the compressor it is also
removed from the compressor pressure relief valve. This causes the valve to
vent all tubing from the compressor to the valve to atmospheric pressure.
8.8
The compressor pressure relief valve is an important part of the compressor
control system. Its function is to vent to atmospheric pressure all tubing leading
from the compressor to the check valve inlet on the rear of the ballast tank
when the compressor is off.
8.9
If the compressor is permitted to start against pressure, its starting current
begins to rise dramatically, causing the compressor to run hotter, increasing
15
wear. The compressor relief valve eliminates this problem.
8.10
The AUX POWER outlet, Figure 1, is a four-conductor connector, one lead (the
red lead) carries power to the cooling fan located within the compressor
silencer housing. Power is applied to the cooling fan continuously, whether the
compressor in on or off, thus maintaining a favorable temperature within the
compressor silencer housing.
8.11
The compressor supplies air via the ballast tank to the pure air generator
through the PUMP fitting, Figure 1 (58), on the rear of the generator unit. This
air passes through the compressor pressure relief valve, Figure 8 (23), through
the check valve, Figures 1, 2 and 9 (24), and into the ballast tank, Figures 1, 2
and 9 (16), where its pressure is monitored by the pressure switch, Figures 5
and 6 (17), and the INPUT PRESSURE gauge, Figure 4 (3).
8.12
At 80-psig the pressure within the ballast tank causes the pressure switch to
open, removing power from the coil of the solid state relay, which in turn
removes power from the compressor and the compressor relief valve.
8.13
When power is removed from the compressor, the compressor pressure relief
valve vents the connecting tubing to atmospheric pressure and causes the
check valve, Figures 1, 2 and 9 (24), to close, confining the pressurized air
within the ballast tank.
8.14
This pressurized air enters the purification reactor, Figures 5, 6, 7 and 7a (18).
During the purification process, the air within the ballast tank is consumed,
decreasing the pressure within the tank again to 60-psig. At this point the
entire procedure is repeated, producing the on and off operation of the
compressor.
8.15
This system will operate efficiently only if some preventive maintenance is
performed every three or four weeks of sustained operation. These procedures
are covered in Section 12.0
16
9.0
PURIFICATION REACTORS
9.1
AADCO Instruments, Inc. offers four basic types of purification reactors,
designated “A”, “B”, “C”, and “D”.
9.2
The “A” PURIFICATION REACTOR produces air of purity outlined in Section
11.0 and with an oxygen concentration of 20.8% ± 0.3%. In addition, the CO 2
concentration will be that of the ambient environment of the user’s locale (~350ppm). This purification reactor should be specified if the operator wishes to
avoid calibration disparities where it is essential that the carbon dioxide level
for both the “zero” air and the sample be the same; e.g., use of the flame
photometric detector or nondispersive infrared. The “A” model is the most
universal purification reactor for air monitoring applications and is usually
supplied when advised of this application.
9.3
The “B” PURIFICATION REACTOR is factory set to produce air with the same
purity as the “A” model but with an oxygen concentration of 37.0% ± 0.5%, at
specified conditions. By in-house experimentation, this concentration has been
found to produce a greatly increased response for most commercial flame
ionization detectors over that response experienced with cylinder air. This has
since been field proven and has become the purification reactor of choice when
high sensitivity FID is required. It has also been found to decrease the noise
level of the flame photometric detector when used in conjunction in a gas
chromatography mode. Use of this purification reactor will eliminate both the
oxygen and air cylinders when operating this detector for that application.
9.4
It should be noted that output flows less than 50% of the rated output should be
avoided with any model pure air generator which contains a “B” reactor. This is
the lower threshold for maintaining the oxygen output at 37%. Flows below this
level will produce an oxygen enrichment greater than 37% oxygen. This higher
oxygen level causes the flame to become too hot with a consequent increase in
noise. This increased noise can be nullified, without loss of sensitivity, by
decreasing the hydrogen flow slightly.
9.5
Those chromatographers actively using flame ionization detectors with pure air
generators having “B” reactors experience a response from three to ten times
greater than the response of the same detector with cylinder air, particularly if
nitrogen is used as the carrier gas. The magnitude of this increased response
will depend upon the particular detector. The substitution of nitrogen for helium
carrier gas will also improve resolution within the GC column. The more dense
the carrier gas the better the resolution.
17
9.6
If the number of flame ionization detectors being fed the output from the pure
air generator with “B” reactor is insufficient to produce a flow of at least 50% of
the rated output volume, it is advisable to incorporate a “tee” bleed valve to
achieve this flow.
9.7
When operating any pure air generator which has a “B” reactor, mixer-receivers
must be incorporated in the system. Their purpose is to homogenize the
oxygen/nitrogen effluent developed by the “B” reactor. It is imperative that no
other chambers be used for this purpose and that these chambers remain
empty.
9.8
The “B” purification reactor should not be used to produce air which is to serve
as diluent in the production of air blends, standards, etc., for air monitoring
equipment. Nor should it be used for instrumentation where air is used as the
carrier gas or support air, as with total hydrocarbon analyzers. The hyper
oxygenation will cause difficulties with calibration and the increased response
will appear as hydrocarbon response even though the air is hydrocarbon-free.
The “A” or “C” purification reactors should be utilized for these applications.
9.9
The “C” PURIFICATION REACTOR is identical with the “A” unit except that the
carbon dioxide concentration will be less than 0.3-ppm, see Figures 12 and 13.
This reactor is mandatory in those situations where carbon dioxide is actually
being measured; e.g., nondispersive infrared where all hydrocarbons and
carbon monoxide are oxidized to carbon dioxide before measurement, the
moving wire liquid chromatograph whereby all carbon dioxide is converted to
methane and measured with flame ionization detection, and those TOC
systems employing the technique. For those situations where the carbon
dioxide serves as an interferant for the analysis of other components, such as
carbon monoxide, the “C” purification reactor must be used. This is the
preferred reactor for FTIR applications.
9.10
The “D” PURIFICATION REACTOR is for those applications requiring high
purity and extremely low moisture. It has the same performance specifications
as the other three reactors but has a moisture content of less than 1-ppm.
Ionmobility analyzers and plasma chromatographs require this purification
reactor. Other applications include air supplies for automatic samplers, valves,
and pneumatic systems. The low moisture content eliminates maintenance
problems with these systems.
9.11
For those instances were pure air with high humidity is required, AADCO
Instruments will supply a humidifier to be located after the pure air generator.
This device will operate under pressure and produce air with 50-90+% RH.
This addition alleviates the drying problem associated with the premapure dryer
used in some air monitoring instrumentation.
18
10.0
METHANE REACTORS.
10.1
The methane reactors are canisters, Figures 5, 7, and 7a (20), containing a
low temperature catalyst, a heating system, and a temperature controller. The
system temperature is factory set at the optimum temperature for the
destruction of methane (about 290 C ± 10 C). A cooling coil Figures 5, 7, and
7a (27) is placed between the methane reactor and the exit fitting labeled
PURE AIR so that the temperature of the effluent hydrocarbon free air does not
exceed 40 C.
10.2
This reactor, when installed in any 737-series pure air generator, is electrically
controlled by the POWER switch, Figure 4 (2), located on the face of the
generator unit. The equilibration time, from initial power, is about sixty minutes.
IT IS ADVISED THAT NO INSTRUMENTATION BE CONNECTED TO THE
PURE AIR GENERATOR DURING THIS INTERVAL SINCE COPIOUS
AMOUNTS OF WATER ARE DRIVEN FROM THE CATALYST DURING THIS
PERIOD, See Figure 14.
10.3
During this initial “burn-in” a low flow of air should be permitted to pass through
the methane reactor to sweep the accumulated water from the reactor and
effluent tubing prior to connection to the using the equipment. A rotameter
reading of about 1/4 scale, set with the OUTPUT FLOW ADJUST, Figure 4
(13), and about 20-psig output pressure, set with the OUTPUT PRESSURE
REGULATOR, Figure 4 (5), should be adequate.
10.4
The methane reactor will accommodate hydrocarbons, methane, and carbon
monoxide concentrations in air to 500-ppm. Most ambient levels are below 5ppm. The life span of the catalyst is almost indefinite though rapidly poisoned
by halogenated and sulfur compounds. It is for this reason that the methane
reactor is always located after the purification reactor. The efficiency of the
methane reactor for methane is expressed by the nomograph on Figure 16.
10.5
The methane reactor is recommended for the generation of air which is to be
hydrocarbon and carbon monoxide free. It is widely used in determining
ambient methane levels, reactive versus non-reactive hydrocarbons, as source
air for CO, CH4, and THC analyzers, preparation of air blends, combustion air
for TOC analyzers, etc. A pure air generator with a “C” purification reactor is
usually employed in conjunction with the methane reactor for these
applications. See Section 9.9.
10.6
To remove the low level CO2 formed during the catalytic reaction, AADCO
Instruments offers an in-line, see through , CO2-indicating scrubber (part no.
737-120). This device is offered for those users who may be concerned with
19
this low level CO2 and have a genuine need for CO2 free air.
10.7
AADCO Instruments offers free standing methane reactors (Models 153 and
154, Figure 10) for those individuals who wish to remove hydrocarbons and
carbon monoxide from their own oxygen or air sources. It should be borne in
mind that suitable halogen and sulfur scrubbers are required if these
compounds are present, when using these free-standing units. The Models
153 and 154 are also ideal for destroying the ethylene used as excitation gas
for chemiluminescent ozone analyzers rather than venting the ethylene within
the monitoring vehicle.
10.8
The temperature of the methane reactor is monitored by the panel mounted
pyrometer, Figure 4 (7). Confirmation that the unit is operating at a controlled
temperature is made by observing the METHANE HEAT lamp Figure 4 (4)
which will cycle when at operating temperature. Should the pyrometer indicate
a temperature other than 290C ± 10C, refer to Section 13.22 for remedial
action.
20
11.0
PERFORMANCE SPECIFICATIONS
11.1
The AADCO 737-series pure air generators produce air with less than 0.005ppm hydrocarbons, carbon dioxide, methane, ozone, sulfur dioxide, hydrogen
sulfide, ammonia, and oxides of nitrogen. Carbon dioxide level is either at
ambient level (~350-ppm) or less than 0.3-ppm, depending upon the model
purification reactor selected. Dewpoint is at least -60 F; i.e., 20-ppm. See
Section 9.0 Purification Reactors.
11.2
Oxygen concentration of the output air is about 20.8% for the “A”, “C”, and “D”
purification reactors and 37.0% ± 0.5% for the “B” units. These respective
oxygen concentrations are determined at -60 F dewpoint and after the units
have been in operation for at least four hours.
11.3
Source air may be from the oil-less compressor normally supplied with the
instrument, suitably filtered “house” air, “plant” air, or any other source,
including cylinders.
11.4
Hydrocarbon content of the unclean input air may be as great as 500-ppm and
the methane concentration to a maximum of 0.2-ppm. For those sources
containing greater than 0.2-ppm methane, methane reactors are required.
These accessory units mount within the cabinets of all models and completely
remove all hydrocarbons, carbon monoxide, and methane by converting these
compounds to carbon dioxide and water. They are low temperature catalytic
oxidizers that, when properly installed, have effluent temperatures no greater
than 40 C. See Section 10.0 for details.
11.5
Output pressure is maintained constant within 0.05-psig through the maximum
output pressure range of each instrument without the use of ballast tanks.
11.6
All 737-series pure air generators are calibrated for purity prior to shipment.
They are standardized for output purity and oxygen concentration against a
factory standard to assure consistent performance among all pure air
generators. This standardization is performed at an input pressure and output
flow commensurate with the rated output flow of the generator being tested. To
reproduce this output purity, the generator must not exceed the maximum
permissible output flow for that unit and must have the proper input pressure
and flow for same. All compressors supplied with the 737-series pure air
generators will meet or exceed the pressure and flow requirements for the
respective units.
21
11.7
Factory conditions for each model are as follows:
737-5
737-10
5-LPM output flow @ 80-psig input pressure
10-LPM output flow @ 80-psig input pressure
11.8
Any output flow greater than the stated maximum output flow for any particular
model pure air generator produces air with purity worse than specifications.
Figures 19 and 20 are nomographs which indicate output flow versus rotameter
reading at STP.
11.9
The operator must realize that once other equipment is connected to the pure
air generator and output flow is controlled at the other equipment, the rotameter
will then be pressurized and will indicate less flow than is actually being
delivered. See Section 4.6.
22
12.0
PREVENTIVE MAINTENANCE.
12.1
BALLAST BLEED - All accumulated water must be bled from the ballast tank
at least once every three days during continuous operation. This is done by
operating the manual toggle valve, Figures 1, 2 and 9 (12), located on the
ballast tank. There should be a firm flow of air from the BALLAST BLEED
tubing, usually accompanied by water which can be caught in a suitable
container and discarded. The tank should be drained completely. During
periods of high humidity the ballast tank should be bled every day.
12.2
BLEED SYSTEM - A weekly routine check should be made for plugging of the
bleed system. When the bleed valve is opened there should be a strong flow of
air from the BALLAST BLEED tubing. If the air flow is weak or no water is
emitted, there is a possibility that there is some blockage within the tubing
leading to the bottom of the tank or the manual valve.
12.3
FILTERS - All filters should be cleaned and replaced once per month if the
compressor operates continuously. The filters in question are the two inlet
filters on the compressor, Figure 8 (44).
12.4
METHANE REACTOR - A one or two minute observation of the METHANE
HEAT lamp, Figure 4 (4), should reveal cycling of the lamp. This gives positive
indication of heat control to the methane reactor. A glance at the pyrometer will
also reveal that the unit is at temperature (290C ± 10C). If either check
reveals some problem, see Section 13.22 for remedial action.
12.5
COMPRESSOR (See Section 7.0) - A check of the INPUT PRESSURE
gauge, Figure 4 (3), over a one or two minute period should reveal: (a) the
compressor is operating properly (reaches a maximum pressure of about 80psig and cuts off), and (b) the pressure switch/compressor pressure relief
system is operating properly (cycles between 60-psig and 80-psig over a one
minute period). If not, see Section 14.0 for remedial action.
12.6
PURIFICATION REACTOR - A one or two minute observation of the rotameter,
Figure 4 (10), should show the rotameter ball as remaining constant. If both the
rotameter ball and the OUTPUT PRESSURE gauge, Figure 4 (6), show sudden
drops during a one minute cycle, see Section 13.8 for cause and remedy.
23
13.0
TROUBLE SHOOTING
13.1
COMPRESSOR (See Section 7.0).
13.2
Depress the PUMP switch.
compressor should start.
(a)
PUMP SWITCH LAMP LIGHTS BUT COMPRESSOR DOES NOT
START. Check INPUT PRESSURE gauge. If reading is 60-psig or
greater, compressor cannot start. Depress POWER switch, so that air will
drain from ballast tank and compressor will start when input pressure falls
to 60-psig or less.
(1)
Input pressure is less than 60-psig and compressor will not start.
Fuse is okay since PUMP switch lights. Problem lies with the
pressure switch, the solid state relay, or the compressor.
NOTE:
13.3
The PUMP switch lamp should light and the
POWER IS ALWAYS PRESENT AT TERMINAL #1 OF AC
RELAY EVEN WHEN PUMP SWITCH IS OFF. TO AVOID
SHOCK, EXERCISE CARE WHEN WORKING IN THE AREA
OR WHEN CHANGING THE RELAY.
FOR SAFETY,
DISCONNECT POWER TO UNIT.
(2)
Check voltage between terminal #4 on solid state relay and neutral
on terminal strip TS-1. Voltage not present indicates problem is with
pressure switch. Confirm by removing pressure switch cover and
shunting between two outside terminals. Voltage should now appear
at terminal #4 on solid state relay and compressor should start. If so,
replace or reset pressure switch as in Section 14.0.
(3)
Voltage is present at terminal #4 on solid state relay but compressor
does not start. Jump between terminals #1 and #2 on solid state
relay. If compressor starts, relay is defective and must be replaced.
(4)
Compressor does not start after jumping between terminals #1 and
#2 on solid state relay. Problem lies with compressor assembly.
THE COMPRESSOR HAS BEEN IN OPERATION BUT HAS STOPPED
SUDDENLY. The unit passes all tests as in Section 13.2 (a) (1) through (4).
Problem must lie with cooling fan or compressor itself.
(a)
Place hand under silencer housing and feel for exhaust air from cooling
fan when PUMP switch is on. If this exhaust air is not felt, remove cover
from silencer housing and observe fan rotation. If the fan is not running,
replace fan.
24
13.3
Continued.
NOTE:
13.4
There is an inaccessible thermal switch located within the body of the
compressor motor which will cause the compressor to shut down
should it begin to overheat. The compressor should begin operating
within fifteen minutes after removing the cover from the compressor
unit. This allows the compressor to cool without cooling fans.
(b)
If the compressor has stopped due to overheating, a visual check should
be made of the plastic louvered shroud, Figure 8, on the front of the
compressor to confirm that it has not become distorted due to overheating.
PERFORM THIS INSPECTION WITH POWER CORD DISCONNECTED
IN THE EVENT COMPRESSOR COOLS ENOUGH TO START. If it is
distorted, remove the shroud by loosening the four screws holding it in
place and check that the four blade fan inside has not been damaged due
to the distortion. Replace one or both, if needed. See Section 18.0, Parts
List.
(c)
If the fan is not defective and the compressor has not overheated but will
not start, replace compressor.
DEPRESSING THE PUMP SWITCH, AS IN SECTION 13.2, THE PUMP
SWITCH LAMP DOES NOT LIGHT. Depress POWER switch confirming that
power is present because if power is present POWER switch lamp should light
as well as the METHANE HEAT lamp, and the cooling fan should operate. If
not, circuit breaker is out and there is no power to unit. Restore breaker. If
breaker okay, check power cord connections.
(a)
Check PUMP fuse. PUMP fuse blown. REMOVE POWER CORD FROM
WALL OUTLET BEFORE CHECKING OR CHANGING FUSES. Replace
fuse with 15-amp SLOBLO. (Use 8-amp if 220V operation.) Must be
SLOBLO. Compressor should start.
NOTE:
(1)
The PUMP fuse will blow if the compressor starting current becomes
abnormally high. This will be due to: (a) the compressor having to
start against pressure, See (1) below, (b) the compressor getting too
warm because the cooling fans in the silencer housing have quit, See
Section 13.3 (a), or (b) a short in the compressor itself, see (2) below.
The compressor pressure relief valve, Figure 8 (23), is installed in
every unit to avoid having the compressor start against any pressure.
To confirm that the compressor pressure relief valve is functioning
properly: when the compressor is running, the ballast tank will fill to
80-psig and turn off. At that instant when the compressor turns off,
25
there should be a sudden expulsion of air from the compressor
pressure relief
13.4 (a) (1) Continued.
valve, Figure 8 (23). This represents a bleeding of air from the
connecting tubing by this valve so that on compressor restart this
tubing will be at ambient pressure. This insures no increase in
starting current. If there is no expulsion of air from the compressor
pressure relief valve when the compressor is off, replace the
compressor pressure relief valve.
In addition, if this air expulsion continues for more than a few
seconds the check valve, Figures 1, 2 and 9 (24), is probably
defective. To confirm, depress the POWER switch to the off position.
The input pressure as shown on the INPUT PRESSURE gauge
should remain at that pressure which was evident the moment the
POWER switch was depressed. If the input pressure continues to
decrease, replace the check valve.
Further confirmation that the check valve is defective: with some
pressure in the ballast tank, turn the POWER switch off and
disconnect the metal tubing, Figure 2 (53), at the check valve,
Figures 1,2 and 9 (24), connect a short piece of plastic tubing to the
check valve and immerse the free end in a cup of water. If air
bubbles are present, replace the check valve. No air should be
released from the tank.
(2)
13.5
To determine if there is a short in the compressor, REMOVE THE
POWER CORD FROM THE WALL OUTLET and disconnect the
black lead at terminal #2 of the solid state relay. If the PUMP fuse
blows when this lead is connected and does not blow when
disconnected, replace the compressor. BE CERTAIN TO REMOVE
THE POWER CORD FROM THE WALL OUTLET WHEN
CHECKING OR CHANGING FUSES.
If a routine check, as in Section 12.5, reveals that the compressor does not
reach 80-psig within thirty seconds, starting at 60-psig, as observed on the
INPUT PRESSURE gauge, with the POWER switch on and the generator unit
operating, then the compressor should be replaced. It is mandatory that this
input pressure be available to the purification reactor for proper operation.
(a)
A further check can be made by turning off the POWER switch and
allowing the compressor to fill the ballast tank until the input pressure
26
reaches 80-psig and the pressure switch cuts off power to the
compressor. This should occur within thirty seconds if the starting input
pressure were at 60-psig and within two minutes if at zero. See Section
14.0 for proper adjustment of this setting if not at 80-psig and 60-psig.
13.5
13.6
13.7
Continued.
(b)
While performing tests in (a) above, it is a good time to check for any
leaks developed between the compressor and the input to the purification
reactor by checking all of the fittings between them with soap solution
WHILE THE COMPRESSOR IS RUNNING and the lines are under
pressure.
This includes all connections on the ballast tank, the
compressor hoses, and the tubing leading to the INPUT PRESSURE
gauge, as well as the tubing leading to the input of the purification reactor.
Any leaks will make it appear as though the compressor is not operating to
capacity.
(c)
A check should be made of the compressor pop-off valve, Figure 8 (48).
Air should not be coming from the valve when the input pressure is below
100-psig. If there is, the valve should be adjusted to eliminate the
leakage. Use a _-inch wrench to loosen the locknut at the end of the popoff valve and a ½-inch wrench to turn the adjustment nut clockwise to
increase the pop-off pressure setting. Once the air leakage has been
stopped, tighten the _-inch locknut while holding the ½-inch adjustment
nut securely to avoid changing its setting. Should it be impossible to stop
the leak, replace the pop-off valve with one which has been pre-set. See
Section 18, Parts List.
IF THE COMPRESSOR CONTINUES TO RUN AFTER THE INPUT
PRESSURE REACHES 80-PSIG AND THE INPUT PRESSURE CONTINUES
TO RISE BEYOND 80-PSIG, THE PROBLEM LIES WITH THE SOLID STATE
RELAY.
(a)
Depress the PUMP switch to off position. If compressor continues to run,
replace solid state relay which is shorted.
(b)
If voltage present at terminal #4 of solid state relay even when input
pressure is above 80-psig, the pressure switch is defective. Make
adjustments to switch as in Section 14.0 or replace with new pre-set
pressure switch, making connections as on old pressure switch.
IF COMPRESSOR CONTINUES TO RUN AFTER THE PUMP SWITCH IS
DEPRESSED TO THE OFF POSITION:
27
(a)
Check voltage between position #2 and position #4 of terminal strip TS-1,
located on the front floor of generator unit (see Figure 18). When PUMP
switch is off, there should be no voltage. If voltage is present, PUMP
switch is defective. Replace the pump switch.
(b)
If no voltage is present in (a) above, check voltage between terminal #2 of
AC solid state relay to neutral of terminal strip TS-1. If voltage is present,
relay is defective. Replace the relay.
13.8
PURIFICATION REACTOR.
13.9
If, as in Section 12.6, a one or two minute check of the rotameter reading,
Figure 4 (10), as well as the OUTPUT PRESSURE gauge, Figure 4 (6), should
both show sudden drops during a one minute observation:
13.10
If the sudden change is only momentary with recovery within a second or two, it
would indicate that the output pressure has been set too close to the low
pressure setting of the pressure switch. For the OUTPUT PRESSURE
REGULATOR, Figure 4 (5), to operate effectively, a pressure differential of at
least 10-psig must be maintained between these two pressure settings with the
low pressure setting of the pressure switch being the higher of the two. Since
the recommended low pressure setting of the pressure switch is 60-psig, the
maximum permissible output pressure, as set with the OUTPUT PRESSURE
REGULATOR, is 50-psig in order to maintain the 10-psig differential. If either
of the above pressure settings do not conform to this restriction, make the
necessary pressure adjustments beginning with the low pressure setting of the
pressure switch. See Section 14.0.
13.11
It should be noted that during some portion of each one minute cycle, for an
interval of about four seconds, there is no purge flow.
This period occurs
when either S-1 or S-2 is activated and, during the same interval, the alternate
valve is energized. Should it be that S-1 is activate, then column one would be
pressurized. The moment S-2 is energized there is a sudden demand for
pressurized air from the ballast tank to fill column two. The ballast tank at this
time may only be at 60-psig, the lower pressure setting of the pressure switch.
If, during this interval, the OUTPUT PRESSURE REGULATOR were set
between 52 and 60-psig the symptoms described in Section 13.9 will prevail.
By observing the four second purge stop-flow interval and simultaneously
glancing at the OUTPUT PRESSURE gauge, one would notice a sudden, sharp
decrease in output pressure simultaneously. This would serve to confirm the
problem as outlined in Section 13.9.
13.12
If, for only one-half of each one minute cycle, there is full output pressure as
observed on the OUTPUT PRESSURE gauge and full pure air flow, as
28
observed on the OUTPUT FLOW rotameter, these symptoms indicate only one
of the solenoid valves on the inlet to the purification reactor is being energized
during the full one minute cycle or that flow through one of the solenoids is
being obstructed.
13.13
During the second half of the one-minute cycle described in Section 13.11,
there will be little or no output flow, as observed on the OUTPUT FLOW
rotameter, and little or no output pressure as seen on the OUTPUT
PRESSURE gauge. This further confirms that only one of the solenoid valves
on the inlet to the purification reactor is being energized during the full one
minute cycle or that, for some reason, flow through one of the solenoid valves
is being obstructed.
13.14
For further confirmation, it is necessary to access the electrical system; i.e.,
timers, etc. Remove the cover from the generator unit and remove the mixerreceivers, Figures 7, 7a and 11 (49), if present.
13.15
Reconnect the power cord and, with the POWER switch on, observe whether
the timer, Figure 5 (41), is fully operational, partially operational, or not
operational.
(a)
Listen for the “click” of the solenoid valves, during one full one minute
cycle of the timer. Each should be energized for alternate halves of each
cycle. If both solenoids “click” the problem is an obstruction in one or the
other solenoid valves on the purification reactor. If the purification reactor
is older than one year, replacing both of the solenoid valves is best. If the
purification reactor is less than one year old, contact the factory for a
complete purification reactor replacement under warranty.
NOTE:
(b)
AADCO Instruments offers a purification reactor complete with all
valves, fittings, etc., for a discounted price with trade-in of the
depleted reactor.
If the solenoid valves do not “click”, disconnect the electrical quickconnects leading from the timer to the purification reactor valve. Measure
the AC voltage at each quick-connect leading from the timer. The voltage
should be 120V or 220V, depending upon the power source, during
alternate halves of the timer cycle.
(1) If AC voltage is not present at both quick-connects, check AC voltage
on input side of timer. If not present, check AC output of RFI filter. If
not present, replace filter.
(2) If AC voltage is present at one quick-connect but not at the other, the
29
problem lies with the timer. Replace the timer.
(3) If AC voltage is present at both quick-connections leading from the
timer, measure the resistance of each solenoid coil at the quickconnect leading to the solenoid valve. It should be about 430-ohms if
120V and 1850-ohms if 220V. If other than this, the coil is either
open or shorted and the solenoid valve should be replaced.
(c)
Check the AC voltage going to and from the RFI filter. If voltage is going
in but not coming out, replace the RFI filter. If both voltages are present,
then the timer is defective. Replace the timer.
30
13.16
If there is purge flow although the POWER switch is off (no power to the
solenoid valves or purification reactor), the problem lies with one of the
purification reactor’s solenoid valves experiencing “blow by”. It is due to the
weakening of the spring within the coil housing. This spring holds the spindle
against its seat when the coil is not energized, effectively closing the inlet side
of the valve at any pressure up to 100-psig. If the spring is defective, air is
admitted through the purge valve and opposite column system rather than
through the check valve, pressure regulator, etc., this air appears as purge air
through the opposite solenoid valve.
NOTE:
BECAUSE OF THE 100-PSIG LIMITATION FOR THE INPUT AIR
PRESSURE, IT IS IMPERATIVE THAT THE PRESSURE SWITCH
NOT EXCEED 100-PSIG. EXCEEDING THE 100-PSIG INPUT
PRESSURE WILL CAUSE IMPROPER OPERATION OF THE
PURIFICATION REACTOR AND, THEREFORE, PRODUCTION OF
IMPURE AIR.
13.17
Further confirmation of this condition can be made by removing the connecting
tubing from the tops of the solenoid valves; i.e., the common dump connection;
and determining which solenoid valve is leaking when its coil is not energized
by feeling the flow from the top of the valve with the POWER switch off and
pressurized air being applied to the solenoid valve inlets. The defective
solenoid valve is that valve which does not evidence purge flow since its
opposite number is leaking when non-energized. Replace solenoid valves.
13.18
If the purge flow is constant (never having no-flow conditions as described in
Section 13.10) or appears to be extremely unequal from one side of the
purification reactor to the other during normal operation with the POWER switch
on, the cause is a defective check valve on the output side of the purification
reactor. To determine which check valve is defective, disconnect a quickconnect leading to one solenoid valve on the input to the purification reactor
with the POWER switch on and pressurized air at the valve inlets. If the purge
air is normal, the defective check valve is on the same half of the purification
reactor as the solenoid valve receiving power. If the purge air is abnormally
high, the defective check valve is on the opposite half of the purification reactor.
Replace the defective check valve.
13.19
Further confirmation can be made that one check valve is defective by: (a)
turning the POWER switch off, (b) remove the ¼-inch tubing, connecting the
output of the purification reactor to the input of the output pressure regulator,
Figure 6, or if mixer-receivers are present as in Figure 7a, the input fitting of the
rear mixer-receiver, (c) connect pressurized air to the output fitting of the
purification reactor, (d) there will be a high flow of air from the top of that
solenoid valve which is in the same half of the purification reactor which has the
31
defective check valve.
32
13.19
Continued.
NOTE:
It may be necessary to remove the ¼-inch tubing joining the purge
connections of the two solenoid valves to isolate that valve which is
producing the improper purge flow.
13.20
Should the cooling fan, Figures 5, 6 and 11 (28), fail, the generator cabinet will
feel unduly warm and the pure air that exits from the PURE AIR fitting on the
rear of the unit will feel warm also, since the cooling fan passes air over the
cooling coil, Figures 5, 6 and 11 (27). To confirm that the cooling fan has
failed, place a hand behind the screened opening on the rear of the generator
unit. If no air flow is evident when the POWER switch is on, replace the fan. It
is held in place by four 6-32 screws with kep-nuts. The electrical connection is
via a push-on connector. Be certain that the replacement fan is oriented
properly to blow air outside the cabinet.
13.21
If the purge valve, Figures 5 and 6 (19), flow setting is accidentally altered,
contact the factory for loan of a proper rotameter and instructions for resetting.
Improper purge flows will cause the production of air which will not meet
specifications.
13.22
THE METHANE REACTOR
13.23
When the POWER switch is depressed, power is applied to the methane
reactor Figure 5, 7 and 7a (20). The METHANE HEAT lamp, Figures 4 (4),
should light and within a few minutes there should be an upscale deflection of
the pyrometer, Figure 4 (7).
(a)
If the METHANE HEAT lamp does not light, wait several minutes to see if
there is an upscale deflection of the pyrometer. If there is, then the lamp
is defective. Replace the lamp.
(b)
If neither the METHANE HEAT lamp nor the POWER switch lights, check
the POWER fuse, Figure 4 (9). REMOVE THE POWER CORD FROM
WALL OUTLET WHEN CHECKING OR REPLACING FUSES. If the fuse
is okay but the pyrometer indicates a temperature rise after a few minutes,
though both lamps are not lighted, replace both lamps.
(c)
If the fuse is blown in (b), remove the cover of the generator unit.
DISCONNECT THE MAIN POWER CORD FROM THE WALL OUTLET.
Disconnect either the black or white lead of the methane reactor, at the
terminal strip. Install new fuse and reconnect the power cord to the wall
outlet.
33
(d)
If the fuse blows when the POWER switch is on, disconnect the power
cord
3.23 (d) Continued.
at the cooling fan, Figures 5, 6 and 11 (28). REMOVE POWER CORD
FROM WALL OUTLET and replace fuse. Reconnect power cord and
depress POWER switch to on position. If the fuse blows, the POWER
switch is defective and must be replaced. If the fuse does not blow, the
cooling fan is shorted. Replace fan.
13.24
If the fuse does not blow in (d) above, the problem is the methane reactor.
(a)
Check resistance between chassis and white and black wires leading to
the methane reactor. If resistance is infinite, methane reactor wiring okay.
Replace fuse. REMOVE POWER CORD FROM WALL OUTLET WHEN
CHECKING FUSES. Unit should operate properly.
(b)
If resistance is zero, there is a short in the wiring inside the methane
reactor. Disconnect black, white and red leads of the methane reactor at
the terminal strip. Measure resistance between red and black leads. This
should read zero, showing continuity through the temperature controller. If
resistance if infinite, replace the controller.
(c)
Measure resistance between red and white leads. Resistance should be
about 50-ohms for 120V or 190-ohms for 220V operation. If resistance is
zero or infinite, replace heater. If infinite resistance, the heater is open
and will not heat nor blow the fuse. In addition, the METHANE HEAT
lamp will remain on constantly. If zero resistance, indicating a short
condition, the fuse will blow.
NOTE:
13.25
AADCO Instruments, Inc. offers a rebuilt methane reactor for a
discounted cost with the trade-in of the depleted unit.
If the pyrometer indicates a temperature other than 290 C ± 10 C and the
METHANE HEAT lamp is cycling, the methane reactor is at proper operating
temperature but either the pyrometer or the thermocouple is defective.
(a)
Disconnect the thermocouple electrical disconnect between the methane
reactor and the pyrometer. Measure the DC voltage output of the
thermocouple at the female disconnect leading to the methane reactor. It
should read fairly close to the 14.0-MV if the unit is at operating
temperature. If not, replace the thermocouple.
34
(b)
If the pyrometer indicates a temperature other than 290 C ± 10 C and
the thermocouple output is about 14.0-MV, replace the pyrometer.
35
14.0
PRESSURE SWITCH ADJUSTMENT
14.1
The pressure switch, Figures 5, 6 and 11 (17), controls the pressure range for
compressor operation. This range is usually between 60 and 80-psig.
14.2
The two opposing but adjacent white, knurled knobs (one considerably larger
than the other) are accessible without removing the dark plastic cover. These
knobs determine upper and lower range settings. They are interactive
adjustments; i.e., varying one will influence the setting of the other but not to a
great degree. The larger knob controls the upper pressure setting and is
continuously variable through ten to twelve full turns. The smaller knob is
variable only through 270 rotation.
14.3
The INPUT PRESSURE gauge is the operator’s pressure reference for the
adjustment procedure.
14.4
With the PUMP switch off and all pressure drained from the system by allowing
the POWER switch to remain on, adjust the smaller, white knob on the
pressure switch about midway of its travel. This is an arbitrary setting and later
will be further adjusted.
14.5
Depress the PUMP switch on and POWER switch off and observe that
pressure on the INPUT PRESSURE gauge at which the compressor cuts off.
This should be about 80-psig. If not at 80-psig but at some lower pressure,
rotate the larger knob clockwise so that the black ring on the knob moves to a
higher pressure setting, as observed on the pressure scale of the switch
(calibration marks 0-260 psig) and vice versa if too high.
14.6
Depress the POWER on switch so that air is bled from the ballast tank by the
system and the input pressure will decrease. Make a note of that pressure at
which the compressor cuts on. This should be about 60-psig.
14.7
If the observed pressure in Section 14.5 were not 80-psig but some higher
pressure, rotate the larger knob so that the black ring on the knob moves
toward a lower pressure reading on the switch pressure scale. As the input
pressure increases, once again note that pressure at which the compressor
cuts off. From the incremental decrease from the initial pressure reading and
the amount that the larger knob was turned, a determination can be made as to
how much, approximately, is required to make that setting for compressor cut
off at 80-psig.
14.8
After completing the setting which controls the 80-psig compressor cut off,
observe the 60-psig reading. If too low, turn the small, white, knurled knob
clockwise to increase its reading and counter-clockwise to decrease its setting.
After each adjustment of the small, white, knurled knob, the larger knob must
36
also be adjusted to maintain the 80-psig cut off because of the interaction of the
two knobs.
14.8 Continued
NOTE:
14.9
ONCE THE SWITCH HAS RESPONDED TO THE PRESSURE
CHANGES BY TURNING THE COMPRESSOR ON OR OFF, IT IS
NECESSARY THAT THE SWITCH PERFORM ITS OPPOSITE
FUNCTION BEFORE THE EFFECT OF ANY SETTING CHANGE
CAN BE PERCEIVED. IF THE COMPRESSOR HAS TURNED OFF,
IT IS NECESSARY THAT THE PRESSURE IN THE BALLAST TANK
DECREASE AND THE COMPRESSOR CUT ON AGAIN BEFORE
THE NEXT OFF PRESSURE READING WILL BE RELEVANT.
SIMPLY ALTERING THE HIGH PRESSURE SETTING AT ONE
END OF THE PRESSURE RANGE OR THE OTHER WHILE AT
THAT PRESSURE, IS IMPRACTICABLE.
It is possible to make fairly close pressure settings for both the 60-psig and 80psig settings by following the directions above. However, if unable to achieve
the 20-psig range nor the 60 and 80-psig readings, replace the pressure switch
with one which has been pre-set. See Section 18.0, Parts List.
37
15.0
COMPONENT REPLACEMENT
15.1
TO REPLACE THE PURIFICATION REACTOR:
15.2
(a)
REMOVE THE POWER CORD FROM THE WALL OUTLET and
disconnect the two electrical disconnects leading to the solenoid valves of
the purification reactor.
(b)
Disconnect the ¼-inch stainless steel tubing at the inlet of the purification
reactor, allowing the stainless steel tubing and all of its connecting tubing
to remain suspended.
(c)
Disconnect and remove the ¼-inch tubing leading from the output of the
purification reactor to the input of the OUTPUT PRESSURE
REGULATOR, Figure 6 (5), unless mixer-receivers, Figures 7, 7a, and 11
(49), are incorporated in the unit, in which case, the tubing will be that
which is connected between the output of the purification reactor and the
rear mixer-receiver.
(d)
Remove the two 10-32 screws on the underside of the generator cabinet
which hold opposite corners of the purification reactor.
(e)
Disconnect the ¼-inch tubing leading to the DUMP connection on the rear
wall of the generator unit.
(f)
It may be necessary to remove the mixer-receivers, if present, to gain
access to the connection on the purification reactor.
(g)
Lift the defective purification reactor from the generator unit.
(h)
To install new purification reactor reverse procedures (a) through (f). It is
not necessary to make any flow adjustments with the new purification
reactor since all adjustments will have been made at the factory. Be
certain to leak check all connections.
TO REPLACE THE METHANE REACTOR:
(a)
REMOVE THE POWER CORD FROM WALL OUTLET and disconnect
the red, white and black leads at the terminal strip, noting connections for
new methane reactor leads, and the two-conductor thermocouple quickconnect between the pyrometer and the methane reactor.
(b)
Disconnect and remove the cooling coil.
(c)
Disconnect the ¼-inch tubing leading from the output of the rotameter to
38
15.2
15.3
15.4
the inlet of the methane reactor.
Continued.
(d)
Remove the three 8-32 kep-nuts from the underside of the generator
cabinet which hold the methane reactor in place.
(e)
Remove the methane reactor from the cabinet and install the replacement,
reversing steps (a) through (d).
TO REPLACE A DEFECTIVE PUMP OR POWER SWITCH:
(a)
REMOVE THE POWER CORD FROM WALL OUTLET and disconnect
the blue and white leads for the switch at the terminal strip.
(b)
Slide the shrink tubing covering the POWER or PUMP fuse back and
remove the black lead quick-connect from the fuseholder.
(c)
Use a 9/16-inch wrench to loosen the nut behind the front panel which
holds the switch in place.
(d)
Unscrew the black switch bezel which encircles the red cap while holding
the switch with other hand. The switch is now free to be removed.
(e)
Before installing the new switch, be certain to transfer the nut and washer
in (c) to the new switch before putting it through the switch hole.
TO REPLACE A PUMP OR POWER LAMP:
(a)
Grasp the red lens cap and pull out of switch to expose the lamp.
(b)
Remove the lamp and insert replacement by shoving into the switch until it
snaps into place.
(c)
Replace lens cap.
39
16.0
737-104 AUTO PURE AIR MANIFOLD.
16.1
Auto Pure Air Manifolding only occurs outside of the pure air generator. See
Figures 11b and 11c. All of the manifolding connections are made outside of
the pure air generator and are visible to the operator.
16.2
The purpose of this manifold is to be certain that pure air is available to the
analytical instruments at all times, whether source air to the pure air generator
is available or not. The air supplies to the manifold are usually pure air output
from the generator and a cylinder of clean air. If the pure air output from the
generator should become unavailable, the air cylinder will automatically
become the source of the pure air to the analytical instruments.
16.3
During operation, the pure air from the pure air generator with output pressure
set at 55-psig is directed to the using equipment. Should the output pressure of
the generator fall below 50-psig (the pressure setting of the standby air
cylinder) the air cylinder will supply air to the instrument until the generator is
once again producing pure air.
16.4
In operation, the Auto Pure Air Manifold is connected to the PURE AIR outlet
fitting on the rear of the pure air generator by means of the swage-type, tubeend reducing fitting. Cylinder air is connected to the manifold inlet fitting
isolated by, and at the inlet to, the check valve. Final pure air connection to the
using equipment is made using remaining fitting.
16.5
Once in operation, the output pressure from the pure air generator is set to 55psig via the OUTPUT PRESSURE REGULATOR, Figure 4 (5), and flows are
established at the instrumentation. The OUTPUT FLOW ADJUST, Figure 4
(13), is completely counter clockwise.
16.6
Once this system is in operation, open the air cylinder and set the output
pressure at 50-psig. Should the supplied system compressor or “house” air
(whichever is being used to supply unclean pressurized air to the pure air
generator) fail, the output pressure of the pure air generator will fall below 50psig and the air cylinder, set at 50-psig, will automatically supply air to the
instrumentation until the system input air source is restored.
40
17.0
737-105 AUTO SOURCE SELECTOR
17.1
Auto Source Manifolding occurs within the pure air generator. See Figures 11
and 11c. None of this manifolding is visible to the operator because all of the
pneumatic connections are inside the pure air generator.
17.2
The purpose of this manifold is to be certain that an air source is admitted to
the pure air generator at all times to assure a continuous flow of pure air from
the unit. The two air sources are usually “house” air and a compressor serving
as the second source in the event the “house” air becomes unavailable.
17.3
In operation, the “house” air, at not less than 80-psig nor more than 100-psig, is
connected to the EXTERNAL SOURCE fitting, Figure 11 (57), and the
compressor with its ballast tank is connected to the PUMP fitting, Figure 11
(58). The “house” air is admitted to the pure air generator and its pressure
appears on the INPUT PRESSURE gauge, Figure 4 (3).
17.4
Depress the POWER switch, Figure 4 (2), and permit the generator to operate
for several minutes. During the interval the operator should note that the input
pressure does NOT fall below 80-psig at any time. If this condition is met, then
depress the PUMP switch, Figure 4 (1). The PUMP lamp “sees” the input
pressure which is greater than 60-psig and will not allow the compressor to
start.
17.5
If the “house” air should fall to 60-psig or less, the compressor will start and
operate as in Section 8.0, cycling between 60 and 80-psig. When the “house”
air resumes at a pressure greater than 80-psig, the compressor will shut off and
the “house” air automatically will become the air source once again.
41
18.0
PARTS LIST.
18.1
Before attempting to replace any part or component, be certain to read the blue
AADCO Instruments, Inc. label on the outside rear wall of your pure air
generator to determine the model number and operating voltage requirements
for proper parts selection.
Reference
Number
16
43
45
28
44
50
40
9
4
1,2
20
Catalog
Number
20049-1
20051-1
20159-2
20159
20158
20159-1
20165
20165-1
20166
20166-1
20034
20010
20156
20150-1
20150-2
737-40
20155-5
20155
Description
Ballast Tank
Compressor, specify voltage
Fan, Compressor-mounted, 4-blade
Fan, Compressor Silent Housing, specify voltage
Fan, Generator Cooling, specify voltage
Fan Screen
Filter, Compressor Intake
Filter Element, spare for above, 2/set
Filter, Generator In-Line
Filter Element, spare for above
Filter, RFI
Fuse Kit, Power and Pump
Lamp, Methane Heat Indicator
Lamp, Power & Pump Switch
Lens Cap, Power & Pump Swtich
Methane Reactor, complete
Methane Reactor Cartridge Heater, 300W,
specify voltage
Methane Reactor Heater Harness, specify
voltage
20155-2
49
3,6
5
737-35
20141
20033
20033-2
18
737-21
18
737-22
7
20149
Methane Reactor Temperature Control Switch,
pre-set
Mixer-Receiver, with tubing and fittings
Pressure Gauge, specify range
Pressure Regulator, Output
Pressure Regulator, accessory, with gauge and
fittings
Purification Reactor, 5-LPM,
Specify A, B, C or D
Purification Reactor, 10-LPM,
Specify A, B, C or D
Pyrometer, pre-wired and calibrated
42
18.0
Continued.
Reference
Number
Catalog
Number
21
10
20169-1
20060
20162
20180
20150
20149-2
20153
20047
20048
20046
20064
20031
20184
1,2
41
23
48
24
13
Description
Relay, solid state, AC, 40-AMP, specify voltage
Rotameter, specify output
Shroud for Compressor Fan
Spring, Compressor Support, Set/4
Switch, Power & Pump, Pre-wired
Thermocouple, Pre-wired
Timer, Specify generator output
Valve, Compressor Pressure Relief
Valve, Compressor Pop-off
Valve, Check, Ballast Tank Mount, Elbow
Valve, Output Flow Control
Valve, Solenoid, purification reactor inlet
Valve, Check, 1/8-inch female pipe end,
purification reactor
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
WARRANTY
AADCO Instruments, Inc. warrants instruments of its
manufacture to be free of defects in material and
workmanship for one year from date of shipment to the
purchaser. Its liability is limited to servicing or replacing any
defective part of any instrument returned to the factory by
the original purchaser. All service traceable to defects in
original material or workmanship is considered warranty
service and is performed free of charge. The expense of
warranty shipping charges to our factory will be the
customer’s responsibility. The expense of warranty shipping
charges to the customer will be borne by AADCO
Instruments, Inc. Service performed to rectify an instrument
malfunction caused by abuse or neglect and service
performed after the one year warranty period will be charged
to the customer at the then current prices for labor, parts,
and transportation. The right is reserved to make changes in
construction, design specifications, and prices without prior
notice.
67
68