mica heaters, band heaters, immersion heaters, extrusion heaters, injection moulding heaters

Cast heaters provide the ultimate long-term solution to machine heating, giving an unrivalled heat source where machine and die physics allow their use.
LPC engineers have developed cast heaters for almost all current process applications including;
Extruder barrels, Injection moulding machines, Hot presses Hot stamping, Textile irons, Multiple colour feeds, Glue pots, Dies and filter units, Mould tools, Curing tables, Sealing bars/platens, Blow moulder heads, Crossheads, Flameproof mediums

Product Notes

Construction
Cast heaters consist of a tubular element which is bent and formed to the required shape then cast into brass, bronze or aluminium as required, care being taken to stay the element during the process to prevent it deforming.
Contact surfaces and critical dimensions are machined to ±.002 inch (0.05mm) and variety of terminations to the cold legs are available.

Design
Cast heaters design lends itself to a much wider range of applications that other heaters. From conventional round, flat, ‘U’ shape or disc types, for example, to the more complex tasks providing barrel temperature control, in the form of air and liquid heater coolers.

Barrel Control
The controller/heater marriage is very sensitive. Under certain conditions straightforward proportional control can result in severe temperature oscillations beyond the tolerance of material being processed.
Proportional, integral and derivative control (PID) minimises this problem by handling the thermal lag times and allowing for the adiabatic heat generated by the screw during processing.
With both air and liquid cooled heaters the control situation can be assisted by careful design of the finning and the cooling tube layout.
Air Cooled System
Finned heater-coolers offer the most economical solution to barrel temperature control as they can be applied as replacements for existing heater systems without the cost of expensive chiller units and softening plant.
Advantages
 Lower costs
 Simple to install
 Generally maintenance free
 Clean and safe to operate
 Easy to install
 Simple to balance and adjust control

Liquid Cooled Systems
Where the rate of cooling achievable with finned heaters-coolers is insufficient then liquid cooled systems can provide the answer, particularly for high speed extrusion where heat generated by the screw during processing is often excessive.
A particular problem with liquid cooled systems is the rate at which mineral deposits tend to accumulate in the cooling tubes. LPC uses a system of deploying large bore tubing (3/8 or 1/2 inch/ 10, 12mm) and designing the layouts in a horizontal free flow method to avoid gravity traps within the heater
Dual tubes can also be provided for extra cooling or as spare circuits for an extended life
LPC can supply complete systems – including heaters, shrouds, fans and controllers if required. Our engineers are happy to advise on any conversion or application required.

Manufacturing Tolerances
Resistance: +/-7%
Wattage: +/- 7%
Voltage: Tubular: 1/4" (6mm) id up to 260volts
5/16" (8mm) id up to 440v
7/16" (11mm) id up to 580v

Loadings:
Aluminium: 40w/sq ins 450 degrees C
Brass/Bronze: 50w/sq ins 650 degrees C

Machining:
Inside Diameter: +/- .002" (0.05mm)
Widths: +/- .002" (0.05mm)

Sizes:
Thickness: Plate heaters 5/8" (15mm) minimum
Round heaters 5/8" (15mm) minimum
Finned heaters 1½" (37mm) minimum
Heater coolers 1¾" (43mm) minimum
Diameter (id): 2" (50mm) min 50" (127cm) maximum
Width: 1" (25mm) min 35" (89cm) maximum

Cooling tubes:
3/8" (10mm), 1/2" (12mm) or 5/8" (15mm)
304 Stainless or Incaloy

Material:
Aluminium: LM4 or LM6 spec
Brass/Bronze: to customer specification

Testing:
All heaters are tested to British standards 1500 volts min Flash Test. Cooling tubes pressure tested to 150 p.s.i.

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