Flexible Tubular Heaters

HotCoils have a larger cross-sectional area and are thus capable of greater power than MicroCoils. For this reason they are used in hot runners with adequate space and where high heat densities are required. Owing to the large number of variants and for cost reasons, the sheath material for HotCoils is stainless steel - the standard for the market and thus also for Freek. HotCoils are large enough that thermocouples can be integrated into them. Our standard here is Type J (Fe-CuNi; red/blue), while Types J and K are also available conforming to the IEC and ANSI standards (see colour codes). Since the measurement point of a built-in temperature sensor is situated in the heater and never where the heat is actually required, a HotCoil with a thermocouple makes particular sense where the application allows the use of larger processing (temperature) windows or where the installation location or the design requires protection against overheating.

Square cartridge heaters are used where much power has to be installed near the surface of a tool, e.g. in cutting knives, sealing stations or hot plates. With a soft, malleable condition in stainless steel or nickel sheath square cartridge heaters can easily be pressed into common milled rectangular grooves. Apart from the advantageous heat transfer over ¾ of the sheath, it is not necessary to cement or cast in the heater which is imperative for round cartridge heaters. Unlike tubular heaters which are also available in square sections (see chapter Flexible Heating Pipes), the square cartridge heaters have the termination on one side and can be loaded with 16W/cm² (2.5W/in²) due to their special inside construction.

Advantages of Heating Plates with Square Cartridge Heaters: -> Simple plate manufacture due to rectangular groove geometry, no deep-hole boring -> Simple heater installation by bending and pressing along the plate surface -> Complex plate geometries with bores and openings -> Optimal heat transfer due to 75% surface contact -> No casting with heat conductive compound -> Uniform temperature profiles due to thermally optimized groove layouts/power distribution and utilization of insulation plates -> high process temperatures (up to 450°C in aluminium, up to 700°C in stainless steel) Example "Heated Stamp": D=100 mm out of tempered tool steel up to max. 700°C continuous temperature. Fitted with 2 Square Cartridge Heaters 1500 W/ 230 V, 4,5 x 4,5 mm x 600 mm, with 50 mm unheated at the termination end. Annealed and formable with a nickel sheath, resistant up to 850°C surface temperature. Connection by fibreglass insulated pure nickel high-temperature leads (max. 500°C)

The Freek heat transfer nozzle heater type especially addresses manufacturers and users who operated their hotrunner nozzles with cast-in heaters in the past and would like to stick to their engineering know-how without paying the high price of this former heater design. The standard material of our patent pending Freek heat transfer alternative is brass, with or without coating, basically with a slit. Characteristics of our HotMicroCoil nozzle heaters sheathed by a reflection tube are easy mounting and variable heat distribution. Because of its direct touch and toleranced fit, the heater allows a very good heat transmission to the nozzle. In all our HotMicroCoils with reflection tube the assembly of a thermocouple is possible and recommended for bigger diameters and power. Also most common nozzle heater solutions are HotMicrocoil heating elements with clamp bands with diverse locking mechanisms.