High pressure hot-air generator KD

Hot-air circulation correspondence Final edition of the electric hot-air generator!!
Catlog
High pressure hot-air generator
KD-series
Kansai Electric Heat Co., LTD.
Rapid hot-air removing water drying by the nozzle
Air-speed : 120m/s
Furthermore, hot-air circulation became possible.
High efficiency multistage blower installation
Discharge air-speed is more thna 12kPa
Heat exchanger can be attached
Inverter is installed to all type
165䢛C Hot-air circulation correspondence
Resisting pressure HEPA filter unit
Hot-air generator
.The following specification may change without notice by product improvement.
Photographs of P.1 - P.3 are all the standard type.
* Noise value measurement method : Hose of 2m are connected to the inlet and outlet of the hot-air generator, and the hose of the outlet is connected to the oven in the general office. And, the average value that was measured in 4 places that parted 1.5m from the hot-air generator is entered.
Common specification
Heat exchanger
.KD High pressure hot-air generator Standard specification list
Remote controller
Inlet Demi-filter
Standard equipment
Rating - Continuation
Insulation - Class E, B, F etc.
It differs by the model and type.
Inlet Demi-filter
Standard equipment
Suction from side by the attachment
of 90ﾟelbow (Accessories)
Remote controller
Remote controller
Ambient temp. - 0ﾟC - +40ﾟC
Ambient humidity - Less than 85% R.H. (Non- condensation)
Standard equipment
Energy conservation - Hot-air circulation type, Inverter control of the blower,
Mode of intermittent operation, Demand signal function,
Switching function of heater output
Inside image
Discard filter cartridge
F-81P
*Standard equipment
Demister filter cartridge
F-81S
*Standard equipment
Inlet Demi-filter
Inlet Demi-filter
Standard equipment
Installation - Place where is not exposed to rain and wind (Indoor). Level condition
Heat can be collected more than 40% by attaching the heat exchanger
at the time of the drying of organic solvent and plentiful moisture.
Exhaust
Inspection window
Heater control method - PID control by the pointless contactor
Exhaust
hot-air
Continuation use max. hot-air temp. - Measurement at the outlet sensor
position of the hot-air generator
Each entry value - Guarantee value by measurement
KD Hot-air generator
Remote controller (Standard equipment)
Fixation metal fittings
Fixation metal fittings
Max. consumption electric power
is the value that summed up the heater capacity and blower capacity.
Please refer to figure of P5.
With filter for exchange 81-P (10 pcs.)
TSK-PN Nozzle
Exhaust
Normal temp.
Normal temp.
(Reference of performance curve)
Normal temp.
(Reference of performance curve)
Normal temp.
(Reference of performance curve)
(Reference of performance curve)
Model
at
Less than
at
Inverter installation, Transformation type of 50 - 100% by the up-down key
56dB at min. air volume - 66dB at max.air volume
59dB at min. air volume - 70dB at max.air volume
-core
-core
-core
at
Less than
Less than
Inverter installation, Transformation type of 50 - 100% by the up-down key
-core
at
at
Inverter installation, Transformation type of 50 - 100% by the up-down key
59dB at min. air volume - 73dB at max.air volume
-core
-core
Less than
Inverter installation, Transformation type of 40 - 100% by the up-down key
Inverter installation, Transformation type of 50 - 100% by the up-down key
Standard installation
Standard installation
59dB at min. air volume - 75dB at max.air volume
-core
-core
Heating exchange material and Outlet-Inlet flange : SUS Outside : ZAM
Resisting pressure HEPA filter unit for High pressure hot-air generator
64dB at min. air volume - 75dB at max.air volume
-core
(With the ground terminal)
61dB at min. air volume - 77dB at max.air volume
-core
Max. use temp. (Radiation side inlet max. temp.)
Max. use air volume
Bore of inlet and outlet od radiation and heat receiving side
Material
Matching hot-air generator
Price
Clean air of the collection efficiency more than 99.97% at 0.3μm
Correspondence possibility
Voltage : 200V
: Designated abnormal voltage
Heater capacity : 5kW
C : With controller
Service terminal
Stop switch
Process temp. display
External temp. control lamp
Hot-air switch
Setting temp. display
External sensor lamp
Blow switch
Air volume control display
Overheat lamp
Timer operation switch
Timer setting display
Temp. abnormal lamp
Timer stop switch
Heater lamp
Blower abnormal lamp
External operation switch
Temp. alarm lamp
Blower capacity : 1.5kW
Test button
Mode switch
Model of the blower
HY : High pressure hot-air circulation
Digital pressure sensor
Installation to KD-82H2 - 82H5
Direction of the outlet of the hot-air
generator and inlet of the blower (only LB)
Outlet of the hot-air generator is left side and inlet of the blower is back-right side
in the condition that the controller was seen from the front.
Outside air
-phase
-phase
Order
Blower
-phase
-phase
Control panel of high visibility
Power supply : 3-phase
High efficiency heat exchanger
(Discharge air-speed of 120m/sec is possibility.)
Type (Standard)
Power supply 50/60Hz
Heater capacity (Current A at 200V)
Explanation of the type
Hot-air collection
Rapid removing water drying system
(With remote cable 10m)
Please refer to figure of P5.
Model
Auto-temp. control range - Continuation use max. hot-air temp. (Accuracy 1%FS)
Bore of the hot-air outlet ･ Bore of the blower inlet *2
Rating performance
Max. air volume
Max. static pressure
Blower suction air temp. at hot-air circulation
Air volume control method
Model of the multistage blower ･ Capacity of the motor ･ Rating current of the motor (At 200V)
Digital pressure sensor
Demi-filter model
Noise At 100% hot-air circulation (Vibration noise measure completion)
Kind of the power cable * Size (Cable length 5m)
Weight
Abnormal voltage specification 50/60Hz
Demand signal function
Price
Control number
Outside air
All switches aqnd lamps are lighted as for the catalog.
2 Accessories : Flange for the outlet, Flange packing, Heatproof silicon gasket, and Glass tape for air leakage prevention.
Discharge side air pressure of the blower is displayed
directly.
Warning sound sounds when the discharge air pressure
exceeded continuation usable max. discharge pressure.
And, the blower abnormal lamp is flickered and all
operation is stopped when this condition was gone on
with for 10 minutes. (Only KD-82H5., Discharge side air
pressure is only displayed about KD-82H2 and 82H3.)
External input-output terminal for KD-72H3 - 82H5
External sensor connection terminal, external control input terminal, operation
and abnormal signal output terminal are standard and be equipped.
External input and output terminal for KD-24H3 and 56H3
Blow output
Connector for
remote controller
Hot-air output
Temp. abnormal output
Discharge sensor
(K-type thermocouple)
Temp. alarm output
Blower abnormal output
External sensor
(K-type thermocouple)
Overheat output
Output common
External temp. control
External operation ON/OFF
External heater ON/OFF
Input common
Blow output
Hot-air output
Temp. abnormal output
Temp. alarm output
Blower abnormal output
Overheat output
Output common
Inside
relay
For SSR drive reverse action output type temp. controller. Input voltage : DC12 - 24V
Terminal voltage : DC12V less than 3.6mA (Contact for unvoltage slight load). ON by close.
Contact capacity : DC5V more than 10mA, DC3V less than 1A. Output common total :
Less than 3A (Output by unvoltage contact signal). Close when the action is abnormal.
Terminal for
remote controller
Terminal
lower Inside
relay
Terminal
upper
External operation ON/OFF
External heater ON/OFF
Input common
External temp. control
External sensor
(K-type thermocouple)
Attention :
Please do not short-circuiting because voltage
DC24V has occurred between the terminal B9-B10.
Option (Order)
Remote controller Remote cable 10m
Highly efficient Demi-filter for hot-air circulation
Remot controller that was
established to the place
where parted from the
control panel of the hot-air
generator can be controlled
simultaneously.
This can be used the repetition by washing the
demister cartridge.
Oil mist can be removed more than 75%.
(The ratio by my company test.)
This is equipped
tandard to
KD-82H5.
Dust collection efficiency : Oil mist of more than 5μm
can be removed 85%. (The ratio by my company test.)
Oil that was accumulated into the filter can be discharged
easily from the drain cap.
Matching hot-air generator
Model
Price
Demister cartridge
Contact capacity : DC5V more than 10mA, DC3V less than 1A. Output common total :
Less than 3A (Output by unvoltage contact signal). Close when the action is abnormal.
Terminal voltage : DC24V less than 7mA (Contact for unvoltage slight load). ON by close.
For SSR drive reverse action output type temp. controller. Input voltage : DC12 - 24V
Please use in accordance with the use example and connectin example after specification
is understood sufficiently by the operation manual when the service terminal is used.
Discard filter
pcs.
Saving electricity
and energy conservation
realization
Differential preassure gauge (Standard equipment)
Model
Matching type
Price
Only KD-82H2, 3
Price
Demand signal function
Operation is switched to the heater output (0 - 100%) and
saving electricity operation by inverter frequency (30 - 60Hz)
that was set up optionally by the demand signal switching
mode when the demand signal (Unvoltage contact signal)
was input from the outside. (Heater is operated only 1 circuit
when heater output was set up to less than 50%.)
Heater output switching function
Filter for the exchange
Model : 81-P
Caster
with adjuster
Combination example
Demand signal function and Heater output switching function installation
Demister cartridge (Spare part)
Ajust range
Max. 15mm rise possibility
Heater output is set to 0 - 100% (heater is operated 2 circuits)
or 0 - 50% (heater is operated 1 circuit) by the heater output
switching switch.
Characteristic
This is the resisting pressure type filter unit that has collection efficiency
of more than 99.97% at 0.3μm and was installed heatproof HEPE filter.
Useless maintenance do not occur because the Differential pressure gauge
that shows the exchange time of the filter is equipped standard.
Life of the high-class HEPA filter becomes long because the removing
method becomes 2 stages in the case that this uses at the same time as
the same time as the high pressure hot-air generator.
This can use to the heat source of the clean room, drying of the medicine
and food. And, this can use to drying of the tank, hopper, sprayer dryer,
and tank lorry for the medicine conveyance that requires pressure.
Model
Max. use hot-air temp.
Less than 250ﾟC at the inlet pf HEPA filter unit
Collection efficiency
Processing air volume
First pressure loss
Final pressure loss
Bore of outlet
Bore of inlet
Resisting pressure
Heat insulation method
Material
Matching hot-air generator
Weight
Price
Model of spare filter
Price
Removing
(At the rating air volume)
(Rough standard in exchange time)
(With flange)
(With flange)
(With flange)
(With flange)
About
Air heat insulation method by double structure
Filter : Glass paper, Filter case : SUS304, Angle : SS+Coating
Explanation of the performance curve
Multistage blower that can draw the characteristic of electric motor output to the maximum was
developed at the time of hot-air circulation in comparison with the conventional product and
general heatproof blower. Performance of the maximum is demonstrated at the time of hot-air
circulation because the sufficient air volume and static pressure are secured (Industry first).
This is the discharge side performance when the suction temp. is 20ﾟC.
Black and orange curve are the static pressure curve when the air volume control is biggest (At 60Hz).
Black curve is the static pressure curve when the suction temp. is 20ﾟC and orange curve is the static pressure curve when the
suction temp. is 165ﾟC. (Heater power is OFF and this was converted to 20ﾟC 1atm.)
Red curve is the discharge hot-air temp. when the heater power is input 100%. Temp. less than this curve is adjusted freely
by the temp. controller.
is the use limit. This machine can not be used more than temp. and less than air volume.
Performance curve
Static pressure
Performance curve
Temp.
Static pressure
Temp.
More than 450mm
Air volume
Figure
Attachment space
More than 250mm
Demi-filter
Figure
Attachment space
More than 250mm
Demi-filter
Air volume
More than 150mm2200
Blower
Blower
Attachment
space
More than
450mm
With
Attachment
space
More than 450mm
Outlet
With
Outlet
Inlet
Inlet
For Service terminal
Wire inlet
Power cable
5m
With
Drain cap
Attachment
space
More than150mm
Attachment
space
More than
200mm
Pitch
Flat-type fixation metal fittings (SUS)
For fixation to the corner and
upper edge dept. of the oven
For fixation to the floor
For fixation to the corner and
upper edge dept. of the oven
Performance curve
Performance curve
Static pressure
Pitch
Various fixation method that combined to the installation place.
L-type fixation metal fittings (SUS)
Flat-type fixation metal fittings (SUS)
For fixation to the floor
Long hole
Attachment
space
More than 150mm
M
M
Power cable
5m
Pitch
Long hole
Pitch
Various fixation method that combined to the
■installation place.
■
Attachment
space
More than
200mm
With
Drain cap
Attachment
space
More than 150mm
L-type fixation metal fittings (SUS)
Attachment
space
More than150mm
For Service terminal
Wire inlet
Temp.
Static pressure Temp.
Air volume
Figure
With
Attachment space
More than 450mm
Outlet
Figure
: KD-82H3
Attachment space
More than 250mm
Hanging position
Hanging position
Attachment space
More than 250mm
Air volume
With
Inlet
This can exchange with the flange elbow
of the belonging.
Outlet
90ﾟ Elbow with flange (Accessories)
Eye bolt
Blower
Eye bolt M10
Attachment
space
More than 150mm
For Service terminal
Wire inlet
Inlet
Discard filter cartridge
Demister cartridge
Demi-filter
Control
panel cover
Control panel cover
Attachment
space
More than 200mm
With
Drain cap
Attachment space
More than 150mm
For Service terminal
Wire inlet
For Heatproof blower
Cooling air inlet
Attachment space
More than 150mm
Inspection window
Attachment space
More than 150mm
Power cable 5m
Demi-filter
Fixation metal fittings
Caster
Free
Pitch
Caster
130 Fixation)
Pitch
Adjuster
(Adjust rang Max. 130mm rise possible)
Please order separately about the figure of KD-72H3 and KD-82H3.
Attachment
space
More than 200mm
Adjuster
Caster
Hour meter installation : Measuring of the product arithmetic operation time of the blower
[ Accessories (For maintenance of blower) ] ･V-belt 4pcs. (3V-560)
･Bearing 2pcs. (Load side 6308ZZ, Opposite load side 6304ZZ)
Power cable 5m
Adjust rang
Max. 10mm rise possible
Highly efficient nozzle
Effect is demonstrated to hot-air rapid removing water and drying by combining with the KD-series.
Four kinds of nozzles made of aluminum and stainless steel are available.
High blow nozzle
TSK-PN nozzle
High blow nozzle SUS
This is the highly efficient nozzle made of the
aluminum that disorder of the air-speed of the
right and left is most few. This can be used in
the ministry space to the small size type.
Model : 15AL, 25AL, 40AL, 50AL
Please refer to the catalog No.10 for
details.
Small size type
Energy conservation type
This is the nozzle made of the aluminum of the
energy conservation type that can obtain high
air-speed by very low pressure loss because
this is light and has the simple inside structure.
Model : 50PN, 65PN, 75PN
Please refer to the catalog No.10-1 for details.
Blow nozzle
This is the nozzle made of stainless steel
of the simple structure, low pressure loss,
and large air volume type. Long type, gate
type etc. can be produced by welding the
nozzle and connecting.
This is the nozzle made of stainless steel of
the compact, high accuracy, and high temp.
specification, This can be used in the ministry
space to the small size type.
Model : 65SUS, 75SUS, 100SUS,
125SUS
Please refer to the catalog No.10-3
for details.
Specification
Model : 25DS, 38DS, 50DS
Please refer to the catalog No.10-1 for details.
Small size type
Energy conservation type
Name
TSK-PN nozzle
Material
Heatproof temp.
Made of Aluminum
High blow nozzle SUS
Made of Stainless steel
Blow nozzle
High blow nozzle
Made of Stainless steel
Made of Aluminum
Resisting pressure
Bore of the air inlet
Slit length
Slit width
Accuracy rating
Characteristic
Low pressure loss, Light
Low pressure loss, Large air volume, Long type Highly efficient, Going straight, Ministry space
Improvement data in moisture drying time
KD-series can discharge the high speed hot-air of max. air-speed 120m/s by concomitantly using
with the our company nozzle because the blower that has a high static pressure is installed.
Discharge air-speed of Nozzle Doldrums
Discharge temp. of Nozzle
(Normal
temp.)
(Normal
temp.)
Moisture drying time
sec.
sec.
Measurement condition
Ambients temp. : 28㺽C Ambients humidity : 52% The air pressure : 1010hPa
Object : Quick-drying WATER PAINTING BRUSH PAPER W150*D100
Discharge air-speed of Nozzle
Water volume : About 16g (Spraying with the sprayer)
Discharge temp. of Nozzle
(Normal
temp.)
Moisture drying time
sec.
Hot-air generator : KD-24H3(3200-7.5C-1.5HY-LB)
TSK-PN nozzle : 50PN-500-1.0
Distance of the object and nozzle : 50mm
Energy conservation by hot-air circulation !!
High temp., Ministry space
sec.
sec.
sec.
sec.
sec.
Discharge air-speed of Nozzle
Discharge temp. of Nozzle
(Normal
temp.)
Moisture drying time
sec.
sec.
sec.
sec.
sec.
sec.
sec.
Discharge air-speed of Nozzle
Heat collection booth
Discharge temp. of Nozzle
(Normal
temp.)
Moisture drying time
sec.
By combining High pressure hot-air generator KD-series
Moisture drying time is shortened to 1/6 - 1/120 !!
sec.
Energy conservation effect in the removing water drying system by High pressure hot-air generator
Energy conservation effect by using the heat exchanger together
Energy conservation effect by hot-air circulation
Case of One way
Air volume : 5.97Nm 3 /min
Discharge temp. : 200ﾟC (Hot-air generator)
Outside temp. : 20ﾟC (Normal temp.)
5.97Nm 3/min * (200ﾟC-20ﾟC) / 46 = 23kW
23kW * Electricity charges JPY20/kW = JPY460
In the case that the exhaust of about 20% was collected by the heat
exchanger at hot-air circulation
Collection air volume : 1.2Nm 3/min
Collection temp. : 60ﾟC
1.2Nm 3 /min * (60ﾟC-20ﾟC) / 46 = 1kW
1kW * Electricity charges JPY20/kW = JPY20
JPY20/1hour is economized in compared with conventional
one way operation.
Fresh air
In the case that the exhaust of about 80% was collected
by the heat exchanger and hot-air circulation
Air volume : 5.97Nm 3 /min
Discharge temp. : 200ﾟC (Hot-air generator)
Circulation temp. : 120ﾟC
5.97Nm3 /min * (200ﾟC-120ﾟC) / 46 = 10kW
10kW * Electricity charges JPY20/kW = JPY200
Heat exchanger
HEXU5
Exhaust
JPY460 - JPY200 = JPY260
Exhaust fan
JPY260/1hour is economized in compared with conventional
one way operation by hot-air circulation.
Hot-air circulation
Exhaust
Hot-air circulation
TSK-PN nozzle
75PN-500-1.0 * 3 pcs.
Discharge air-speed : 100m/s
Discharge temp. : 180ﾟC
Necessary air volume : 3.3m3 /min (1.99Nm3/min) *At 1 pc.
Necessary static pressure : 8kPa
High pressure hot-air generator
KD-82H2
Heater capacity : 30kW
Blower capacity : 5.5kW
Consumption electricity capacity of 57% and cost of JPY260/1hour can be cut in
comparison with the hot-air generator of conventional one way specification because
KD-series that multistage blower of the hot-air circulation type was installed was adopted. (Our ratio)
Fresh air
Exhaust
Automatic conveyance type washing machine
Removing water drying introduction example
Removing water
drying room
Water is removing by strong air and is dried by the
hot-air in the ministry space (Few High blow nozzle)
because High pressure ht-air generator is introduced
to the removing water hot-air drying room.
FW-filter
High efficiency
heat exchanger
HEXU-sries
Hot-air drying room
Washing vessel
Line speed
30m/min
Exhaust 5 - 10%
High blow nozzle
Discharge air-speed 100m/s
Discharge temp. 100㺽C
Discharge air-speed 50m/s Hot-air temp. 120㺽C
Please evacuate forcibly without fail inside the
removing water room because drop of water that
scattered is floating in the fog state.
Please establish the hot-air drying room. And, the
parts of complicated earmarking can dry completely
with energy conservation by adopting the hot-air
circulation system with the hot-air generator.
Fresh sir 5 - 10%
High pressure hot-air generator
KD-series
Hot-air generator
TSK-C series
Demi-filter
High pressure hot-air generator of Industry first, Correspondence to hot-air circulation, and Ultra energy conservation
New type KD- series
Old type TSK-H series
High efficiency multistage blower
Vortex blower
In comparison with TSK-H series
Hot-air can not to circulate
Hot-air to 165ﾟC can circulate
Energy conservation
Heat exchanger can be attached
Energy conservation
of Max.
80%
In comparison with TSK-H series
Heat exchanger can not be attached
of Ave.
40%
In comparison with Vortex blower
Vortex blower that consumption electric power is big is installed
Energy conservation
Multistage blower that consumption electric power is small is installed
of Max.
56%
(Our ratio)
Ultra energy conservation was materialized by Hot-air circulation
High pressure hot-air generator of hot-air circulation specification has been developed newly.
Hot-air circulation of max. 165ﾟC can be correspond at the inlet of the multistage blower. Consumption electric power of 50% - 80% can be economized
in comparison with one way operation by the application of the hot-air.
We recommend the use of the heat exchanger in the case that organic solvent (Explosiveness solvent) and plentiful moisture are included to the gas that
is heated.
Exhaust heat of the exhaust gas is used effectively by attaching the heat exchanger. Energy of ave. 40% can be cut when HEXU-series is used in
comparison with one way operation.
Preeminent energy conservation effect is demonstrated in the high speed hot-air system because the high pressure hot-air can circulate by the
adoption of multistage blower and the heat exchanger is attached.
(Example) Cost-down by hot-air circulation (Our ratio)
Electricity charges of case that Model : KD-56H3 was driven with one way.
･ Heater capacity : 12.5kW ･ Heater output : 100%
12.5kW * JPY20/kW (Electricity charges) = JPY250/hour (Max.)
Electricity charges of case that 80% of heat were collected by hot-air circulation.
12.5kW * 0.2 * JPY20/kW (Electricity charges) = JPY50/hour ･･････････ Cost-down of JPY200/hour in comparison with one way
Electricity charges of case that 40% of exhaust heat were collected by the heat exchanger.
12.5kW * 0.6 * JPY20/kW (Electricity charges) = JPY150/hour ･･････････ Cost-down of JPY100/hour in comparison with one way
* Electricity charges are calculated with JPY20/hour per 1kWh.
Installation of the high efficiency multistage blower
Multistage blower is very ideal high efficiency blower of low noise and low generation because it is attached the several steps light impellers made
of aluminum to 1 motor shaft. (Energy conservation)
Vortex blower that has very high pressure is installed to old type TSK-H series. But, the air volume is few constructionally and hot-air can not circulate.
Furthermore, the affinity with the inverter is bad and A part of motor output becomes the high noise of high frequency and there is generation.
Consumption electric power of more than 50% can be reduced in the case that themotor shaft output of the multistage blower and vortex blower
are compared at the same pressure.
(Example) Cost-down by high efficiency multistage blower (Our ratio)
・ Necessary air volume : 4.8m 3 /min ･ Necessary static pressure : 10kPa
Electricity charges of case that the vortex blower of equal performance was used.
Necessary motor capacity 5kW * JPY20/kW (Electricity charges) = JPY100/hour
Electricity charges of case that the multistage turbo-blower was installed to KD-56H3 was used.
Necessary motor capacity 2.2kW * JPY20/kW (Electricity charges) = JPY44/hour ･･････････ Cost-down of JPY56/hour in comparison with the vortex blower
* Electricity charges are calculated with JPY20/hour per 1kWh.
Usage example
Fresh air
A part the exhaust
To hot-air circulation of rapid
removing water drying process
High pressure hot-air generator
TSK-PN nozzle
Removing water drying of the can etc.
Removing water drying of the printed circuit board
Removing water drying of the heating exchange fin
Removing water drying of the bottle etc.
Energy of max. 80% can be cut by the
conventional rapid hot-air removing
water drying process is changed from
the one way system to hot-air circulation
system.
Removing water drying of the film and printing
Removing water drying after the washing of the tray
Removing water drying of the vegetable etc.
Removing water drying of the basket
Condensation removal and drying of the steel board
Removing water drying after the washing of the mesh conveyor
Removing water drying of the wire material
Hot-air removing water drying of plate glass
Drying of the pellet inside the hopper
Air curtain at the opening and
closing of the factory entrance
shutter in winter
Hot-air generator
Production
& Sales
Kansai Electric Heat Corp.
4-18,Takaidanishi 5-chome, Higashiosaka-city,
577-8566 JAPAN
TEL : +816-6785-6001 FAX : +816-6785-6002
URL : http://www.kansaidennetsu.co.jp
Hot-air removing liquid drying after the acid
cleaning in the rolling process