Aluminium Compact Thermal Immersion Heaters Can

January 2013
Volume 7, Issue 1
ask the expert...
aluminium compact thermal immersion heaters can
improve efficiency during the metal-transfer process
Don Nikolet,
USA Product Manager,
Billet Casting–
Aluminium
To efficiently and consistently control heat distribution
in a molten metal bath, Pyrotek offers an Aluminium
Compact Thermal (ACT) immersion heater geared toward high-temperature metal processors and foundries.
The heaters feature electrical control systems custom
designed by Pyrotek. Here, Billet Casting Product Manager for Pyrotek’s USA Aluminium Division, Don Nikolet, highlights common questions regarding this solution.
Q: What are the primary uses of the ACT immersion
heaters?
A: ACT immersion heaters are used to maintain metal
temperature during the metal-transfer process. They
typically are used in furnaces of 680 kg (1500 lb) or less,
and immersed in a molten metal bath of aluminium,
zinc or magnesium. Process applications include in-line
degassing systems, a portable in-line heat source during
continuous casting, melting and holding furnaces, lowpressure diecasting furnaces, dosing furnaces, transfer
ladles and more.
Q: Does Pyrotek sell the immersion heaters globally?
A: Yes.
Q: What are the specifications?
A: Pyrotek offers both vertical and L-shaped versions
of the heaters. Vertical heaters range from 500–1500
mm (1.6–5 ft) in length and 32–55 mm (0.8–2.2 in) in
diameter. The L-type ranges from 660–900 mm (2–3 ft)
in length and 32–55 mm (1.2–2.2 in) in diameter. The
heat output ranges from 8–30 kW with a heating efficiency of 98%. The lightweight heaters are constructed
with an outer sialon ceramic sheath and three internal
heating elements. Inside, a layer of boron nitride paste
surrounds a thermocouple, which protects the element
from overheating. The connecting voltage ranges from
45 to 600 volts, or up to 30 kW. The size a customer
needs depends on the vessel’s size, metal volume and
temperature requirements.
Q: If I have a low metal level situation, is there a
heater that can help?
A: Yes, the L-shaped immersion heater will prevent the
metal from freezing during transfer. An alternative way
to heat the metal is with a natural gas burner, which only
heats the surface of the metal and leads to increased
dross production. An immersion heater would keep
natural gas out of the area.
Q: Should the heaters be preheated and how does
this affect them?
A: ACT immersion heaters do not need to be preheated;
they should not, however, be cold when inserted
into the bath, so they may be turned on just before
insertion. According to the manufacturer, no preheating
of the empty furnace or heating in the air should be
performed. Heating in the air will lead to the element’s
deterioration.
Q: What is the heater’s life expectancy?
A: About nine months, with proper use and cleaning.
Q: How is the heater maintained?
A: The immersion heater needs to be cleaned when
hot. The best practice is to clean the element when
the heater is just being removed from the bath. This is
when the metal is most easily removed. Recommended
methods for cleaning depend on use. Contact your
Pyrotek sales engineer for recommendations.
ask the expert... (continued)
Q: How is the heater powered?
A: Pyrotek makes a 3-phase, 480 volt control panel that serves as the
power supply for each heater at its Cortland, New York, USA, facility.
Each one is different because it depends on the number or type of heaters
or the voltage a customer requires, so the control panels are customised.
They are similar in nature but different, depending on how a customer
plans to use them. The control panels deliver the electricity and are
programmed to control thermostatically the heat output. All units are
factory tested before being delivered to the customer. Pyrotek improves
customer performance with a fully integrated package, coupled with the
expertise and technical support of global Pyrotek personnel.
www.pyrotek.info