Walter Lichtenberger, Head of Temperature Control Technology at WITTMANN Kunststoffgeräte GmbH in Vienna.
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The TEMPRO basic C120 single-circuit temperature controller with direct cooling from WITTMANN is also available with touch screen as an option – and from 2017 with revised software for even greater operating safety. |
From 2017, the WITTMANN TEMPRO basic C120 temperature controllers with direct cooling will be available with brand new software features. With their familiar easy operating comfort, these appliances will make an even more effective contribution to improving safety in production.
Temperature controllers with direct cooling from WITTMANN can operate at temperatures of up to 120 °C and are used wherever a high cooling performance is required. To achieve a high cooling performance, the cooling water is not used indirectly, flowing through a cooling coil, as is the normal practice, but the water inlet is connected directly to the heat exchanger.
Consequently, the operating temperature of the appliance depends indirectly on the water inlet pressure.
Previously, the minimum inlet pressure – 2 bar on the vapor pressure curve shown below – and the highest permissible temperature of 120 °C were linked in temperature controllers with direct cooling laid out for 120 °C. The consequence was that these appliances could not be operated at a water inlet pressure below that minimum. In such cases, the pressure setting had to be adjusted to the actual conditions manually via the appliance’s display.
New software features offer added safety
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This steam pressure curve illustrates the correlation of water inlet pressure and maximum operating temperature. |
New (or overworked) software for the WITTMANN TEMPRO basic C120 appliances means that the system pressure (water inlet pressure) is measured continuously, and a maximum temperature limit is set automatically. If the operator should attempt to set the maximum temperature higher than the calculated maximum temperature setting, the LED set value display flashes and issues a warning. This clearly indicates that an increase of the set maximum temperature is not possible for safety reasons, as the water inlet pressure is too low. At the bottom of the scale, a minimum pressure of 1 bar is fixed in order to prevent cavitations inside the pump case.
The second new software feature of TEMPRO basic C120 also serves to improve occupational safety. To ensure the safe opening of the magnet valve, a fixed maximum differential pressure must not be exceeded. Therefore the temperature controller software is now programmed for pressure reduction at 6 bar in order to protect the functionality of the magnet valve.
Finally, another feature has been added in order to improve venting of the appliance during the heating phase. Due to long hoses and deflections inside the mold, air may be trapped in the temperature control circuit, and this may lead to substantial costs for repairs. Air bubbles inside the system may cause dry running inside the pump case, which may accelerate the wear and tear of the mechanical seal and thus cause exposure of the heating element. The new TEMPRO software ensures a cyclical opening of the cooling magnet valve during the appliance’s heating phase in order to release the trapped air from the system. This feature not only prevents potential costs for repairs, but also provides a more effective heat transfer to the mold.
All in all, and thanks to these new software features, the TEMPRO basic C120 temperature controller now offers considerable improvements in production safety.
