Electrical high temperature heating elements

heating elements

JTEKT Thermo Systems is represented in Europe by
Crystec Technology Trading GmbH

Electrical high temperature heating elements Moldatherm^®

JTEKT Thermo Systems (previously Koyo Thermo Systems) produces different kinds of heating elements, which have a very low thermal mass, caused by their type of construction. A rather thin resistance heating wire is molded directly into a special ceramic material, following a patented process. The ceramic material also serves as an insulator.

Since the heating wire is arranged in a deepening and molded into the ceramic, no contact to component parts inside the heater can take place at normal conditions, without effecting heating performance. No short circuit can occur when using metal components inside the heater.
The life time is increased compared to other heating elements, where the heating wire is attached on the surface. This is the case since extension or deformation of the molded wire is prevented over the life span of the heating element.
Using this procedure, thinner heating wires can be used due to the stabilizing effect of the ceramic.
- The result is a lower energy consumption during heating.
- By using a thinner heating wire and the resulting lower heat capacity of the heating element, the heater is less sluggish and can react more quickly to signals from the controller.
- This enables better temperature control, which has a significant effect especially at "low" temperatures of up to 400 ° C.
- The temperature uniformity is increased.
- In addition, an overshoot of the temperature at the end of the heating period can be prevented.

Heater design

Two types of Moldatherm^® heaters are available. The plain type is used in JTEKT Thermo Systems conveyor furnaces. It can be used also individually by the customer for the construction of special furnaces or furnace chambers or heating areas. The half cylinder type of the Moldatherm heating elements can be used by customers to design high temperature heating mantles for tubes. A tube-like heating element is used by JTEKT Thermo Systems in a special setup for the production of tube heaters for semiconductor tube furnaces. These special LGO heating elements for semiconductor furnaces, tube furnaces and diffusion furnaces are described on a separate page, called "LGO heating elements".

This heating elements can be used for temperatures between 140°C and 1200°C.

On this page, we want to inform customers, who want to realize their own application with JTEKT Thermo Systems modular heating elements, about the details of the available heaters. We can also offer you the required temperature control.

Plain Type Moldatherm^® Heating Elements

Moldatherm block heating element

Type		Output(W) / Voltage(V)		Dimension(mm)	Heating Area EXF(mm)	Heater Area Row	Terminal Position
PR	PL						No.	G
PR-11	PL-11	1390W/50V	1680W/55V	375 (A) X 225 (B)	322X197	8	(1) (2)	30
PR-12	PL-12			375 (A) X 475 (D)
PR-13	PL-13			625 (C) X 225 (B)
PR-21	PL-21	2750W/100V	3330W/110V	450 (A) X 375 (B)	406X346	10	(1) (2)	26
PR-22	PL-22			450 (A) X 625 (D)
PR-23	PL-23			700 (C) X 375 (B)
PR-31	PL-31	6180W/200V	7480W/220V	750 (A) X 450 (B)	700X422	17	(1) (3)	29
PR-32	PL-32			750 (A) X 690 (D)
PR-33	PL-33			990 (C) X 450 (B)

All heating elements are only available in the specified sizes. The heating elements are relatively easy to cut in the area free of the heating wire and drilling holes, e.g. for thermocouples, is usually not a problem.
The PL type differs from the PR type since the heating elements are preheated in the factory and therefore show smaller shrinkage when heated for the first time. The PL type is designed for temperatures up to 1200°C. With the PR type, minor changes to the dimensions after installation are to be expected. The PR type is designed for temperatures up to 1100°C.
The heating elements are available in 3 heating surface sizes (1st digit of the type designation).
As you can see in the pictures above the table, three types of heating elements are available per size (last digit of the type description). Type 1 (Fig. 1; far left) uses almost the entire area for heating, while type 2 (Fig. 2) and 3 (Fig. 3) have insulated areas without heating wire left and right or at the top and bottom. Please compare the column dimensions with the column heating surface in the table.
The 4th picture shows the back of a heating element with the electrical connections. Figure 5 shows a ceramic block without heating wire, which is also available in all available sizes.

Dimensions flat heater PR

Half Cylinder Type Moldatherm^® Heating Elements

half cylinder type low thermal mass heating elements

Type		Output(W) / Voltage(V)		Inner Diameter A (mm)	Outer Diameter C (mm)	Length C (mm)	Heater Length D (mm)	Heater Row		Terminal Position
HR	HL									E (mm)		F(mm)		No.
HR-1030	HL-1030	780W/50V	950W/55V	100	300	300	238		6		61.8		60		(1)(2)
HR-1045	HL-1045	1030W/50V	1250W/55V			450	406		10		53.3
HR-1530	HL-1530	1110W/50V	1340W/55V	150	350	300	238		6		62.3
HR-1545	HL-1545	1690W/50V	2040W/55V			450	406		10		54
HR-2030	HL-2030	1320W/100V	1600W/110V	200	400	300	238		6		61.6
HR-2045	HL-2045	2170W/100V	2630W/110V			450	406		10		53.3
HR-3030	HL-3030	2310W/100V	2800W/110V	300	550	300	238		6		62.3		80
HR-3045	HL-3045	3290W/100V	3980W/110V			450	406		10		54
HR-4045	HL-4045	4470W/200V	5410W/220V	400	650	450	406		10		53.3
HR-4060	HL-4060	6070W/200V	7340W/220V			600	532		13		65.8				(2)(3)

All heating elements are only available in the specified sizes. Drilling holes, e.g. for thermocouples, is usually not a problem.
Normally, 2 half-cylinder heating elements are put together to form a tubular heating element. With the help of this half-shell design, user-friendly, foldable heating elements can be produced. Alternatively, JTEKT can offer complete cylindrical heating elements . However, these are only available as spare parts for JTEKT furnaces that are matched to the corresponding systems. The HL type differs from the HR type since the heating elements are preheated in the factory and therefore show smaller shrinkage when heated for the first time. The HL type is designed for temperatures up to 1200°C. With the HR type, minor changes to the dimensions after installation are to be expected. The HR type is designed for temperatures up to 1100°C. With the HR type, minor changes to the dimensions after installation are to be expected.
The heating elements are available with 5 different diameters and 2 different lengths each.
The heating wires are sunk into the insulation layer; however, a certain distance from the material to be heated is recommended. For example, a pipe that goes through the heating elements should have a maximum of half the inner diameter of the heating element.
The first picture shows the structure of the heating element from the inside. The second picture shows the electrical connections on the outside. There is also insulation material without heating wires for all sizes (third picture).

Drawing half cycle heaters HR

Here is a summary of the special features of Moldatherm^® heating elements:

Moldatherm^® heaters have superior temperature uniformity,
offer fast temperature ramping (heating and cooling),
offer superior control at low temperatures (from 140°C!)
and can reach temperatures up to 1200°C.
There is almost no overshooting in temperature.
Durability and extended lifetime are key features.
You can save electricity, using environmental friendly Moldatherm^® heaters.

Electric heating elements are suitable for the following temperatures
200°C	300°C	400°C	500°C	600°C	700°C	800°C	900°C	1000°C	1100°C	1200°C

Installation and Handling

The following pictures show the terminal connection for Moldatherm heater -lead wire connection at low temperatures (left) and high temperatures (right)

Low-Temperature-Connection High-Temperature-Connection

A: Heat-resistance wiring; B: Crimp terminal; C Aluminum strap or heat resistant component

The terminals are covered with a thin oxide film. Use sandpaper to grind the terminal surface, apply conductive paste, then use two wrenches to adequately tighten the nuts and bolts.

In the following picture proper sealing of slots between heating elements by high temperature blankets is shown.

Heater-sealant

D: Ceramic fiber blanket

In order to achieve a good sealing, fold the 6 mm ceramic fiber blanket in half and insert it between the two heating element units so that it is secured.

For temperature control a PID/SSR based method is recommended.

Heater-Control-System Heater-Control-System2

The position of the thermocouple on the core side should be at least 30 mm away from the furnace surface.

Furthermore please note the following handling instructions. Moldatherm heaters have porous surfaces that make them highly susceptible to oil, moisture and gas absorption and permeation and therefore need a protective atmosphere and protective measures tailored to the properties and states of the workpieces.

Use in a protective atmosphere
1. There are no problems with using air or nitrogen gas as the furnace atmosphere, but protective measures are needed when using other atmospheres.
2. Use a muffle for furnace gases that generate soot such as endothermic or exothermic furnace gases.
3. Using a muffle is also recommended for highly reductive or penetrative gases such as dissociated ammonia gas or hydrogen gas.
Protective measures for workpiece emissions
1. Oil adhering to or absorbed by Moldatherm heaters can carbonize and cause short circuits and insulation drops.
2. Gases and other workpiece emissions can also adversely affect Moldatherm heater components such as heating elements and fibers.
3. To prevent these problems, be sure to properly investigate workpiece states and properties before placing workpieces in the furnace. (Check possible issues such as the content of oil, moisture and other volatile components, and the potential for degassing caused by heating.)
4. When designing furnaces, determine the properties of the workpieces to ensure that the furnace body structure will incorporate appropriate protective measures.
Moisture prevention
1. Since moisture absorbed by Moldatherm heaters can cause short circuits, allow the heater to dry for 1 to 2 hours at 600°C during test operation.

JTEKT Thermo Systems is represented in Europe byCrystec Technology Trading GmbH