Contact

Tel.: +49 (0) 22 91 / 796 - 0

e-Mail: info(at)gc-heat.de

Products

FAQ

Any questions? Here, we provide some answers to your most important and frequent questions. In case the matching answer cannot be found, we will be more than happy to personally assist you via telephone, e-mail or fax without any bureaucracy whatsoever.

1. What is the life expectancy of the heating elements?

The life of heating elements is variable because this is particularly dependent on the following factors:

  • the operating temperature of the medium to be heated
  • the thermal surface load (W/cm²)
  • the heat loss
  • the temperature control
  • environmental conditions such as moisture and dirt

We use state-of-the-art materials for our heating elements for which we have very high quality demands. We are available for you anytime, to help you mount the heater cartridge that optimally suits your requirements.

2. How should the bore holes be provided for the ground "GC-cart” heater cartridges?

We recommend the use of an H7 bore hole.

Nominal diameter in mm6...1010...1818...3030...50
Tolerances for H7 bore hole in microns+15+18+21+25

By default, the ground “GC-cart” heater cartridges are delivered with a nominal diameter between -0.02 mm and -0.06 mm.

3. Is the use of fitting grease useful?

Most pastes are mixed with an oil mixture that can considerably ease the installation. This oil will evaporate at temperatures of about 250° C. The hereby developing vapours can, after penetrating to the heating element cause damage such as short circuits.

The GC-heat “boron nitride spray” has very good separating and lubricating properties. It can be used in conditions with a very confined tolerance clearance and also improves the thermal conductivity. Since this is a ceramic product, it can be used with peace of mind.

4. What happens if a different voltage than the one specified is applied to the heating element?

An electrical heating element is an ohmic resistor so the performance depends on the applied voltage.

R = U² / P R = resistance (Ω), U = voltage (V), P = power (W)
In case of a 10 % higher voltage (as designed) the performance will increase by +21 %.

5. How high is the switch-on power?

During commissioning, the switch-on power (especially with high-performance heater cartridges) can be 7-9% higher than the rated power in the warm state (one-time recrystallization).

The switch-on power can be 3-5% higher than the rated power in the warm state (one-time recrystallization). This is due to the decrease in the specific resistance from hot to cold.

The tolerance of the performance (manufacturing tolerance) and the increased switch-on power can accumulate.

6. How are heating elements stored?

A hygroscopic insulation material is used for high-value heating elements. This will draw moisture during prolonged storage times and thereby reduce the insulation resistance. The moisture can be eliminated through heating with a reduced power induction or drying in an oven at 180° C for 8 hours.

7. What is and what purpose does a start-up ramp or ramp-up controller have?

The ramp-up controller is intended for the gentle operation of heating elements. Hereby, the heating element is slowly heated to 100° C so that any moisture is discharged from the heating element and damage, for example, through a short circuit can be avoided.

8. What is the easiest way to extend the connections?

For this purpose, the same materials should be used. Nickel wire should, for example, be extended with nickel wire. For this, the appropriate crimp sleeves should be used. We offer different tubing for the insulation of the crimping points. To avoid temperature differences in thermocouple wires, these should only be extended with the same material. Please consult us in this kind of matter because we will probably have the proper materials available for you in stock.

9. What does the stamp say about the heating element?

To guarantee traceability of the orders, we will stamp all heating elements with the order and item number. The first two digits contain the year of the order. In addition, the designed voltage and power will be stated.

10. Can heating elements be shortened?

No. Heating conductor wires with ceramic are processed in the heating elements. These heating conductor wires are designed for a specific voltage and power and if they are shortened the heating element will be defective.

11. What temperatures can the connection terminals tolerate?

Silicone impregnated glass fibre insulated nickel wire:up to max. 350 °C
Silicon connection wire:up to max. 180 °C
Teflon connection wire (PTFE):up to max. 260 °C
Glass fibre insulated connection wire type M:up to max. 600 °C
Ceramic coated connection wire:up to max. 750 °C

Note: The above-mentioned temperatures refer to the static operation of the connection wire. During a prolonged temperature load of more than 200 °C, the silicon information will discharge from the glass fibre insulated connection wires. The wire can become brittle through movement.

The minimal bending radius (r min) of the glass fibre insulation connection wire is 10 x wire external diameter (ED) – example: at 0.5 mm² cross-section area, the external diameter is 2.0 mm.
The minimum bending radius is then calculated as follows: r min = 2.0 mm x 10 = 20 mm.

12. Can the unheated sections of a “GC-coil” be bent?

The first 10 mm after the connection head and the 10 mm before the helical area should not be bent. Between them, the unheated areas can be bent once with the indicated bending radius.

13. How can I place a “GC-coil” onto a nozzle?

A "GC-coil" should be screwed onto a nozzle so that it has an optimum fit on the nozzle. We manufacture these with an inner diameter tolerance of

≤ 12 mm inner diameter with -0.05 / -0.2 mm
> 12 mm inner diameter with -0.1 / -0.3 mm

14. What is the maximum permissible bend radius of a “GC-cart”?

The “GC-cart” depends on the diameter and length. It is elastically flexible and, therefore, facilitates the insertion into bore holes. For the “GC-carts” with a diameter D ≥ 20 mm and an outside diameter tolerance of -0.02 mm/-0.06 mm, the maximum factory-designed curvature is 0.3 mm per meter (L) (see illustration).