We have compiled a selection of solutions for frequently asked questions for you under FAQ. If you require further information, our temperature control specialists will be happy to answer your questions about temperature control using liquid media. Please use the contact form for this purpose.
Temperature control units can be used in any application in which the consumer (mould, die, roller, container, etc.) to be connected to the temperature control unit is heated to production temperature by means of corresponding holes/channels through which circulating water of thermal oil flows. During production that temperature is held by means of heating and/or cooling. The number of potentials fields of application/possibilities is extensive.
Heating the consumers (mould, die, roller, container, etc.) to their operating temperature. Keeping the consumer at its operating temperature (regardless of production conditions, such as changes in cycle time, production interruptions, etc.)
These tasks result in:
- Optimal cycle time
- Consistent high-quality products
- Maximum outlet temperature
- Heat transfer fluid
- Heating capacity
- Cooling capacity
- Pump capacity (flow rate/pressure)
- Operating voltage
Units are differentiated by whether they operate on water, oil (or glycol). Units using water usually have a maximum outlet temperature of 90 °C or approximately 160 °C for pressurised water units. Units using oil usually have a maximum outlet temperature of approximately 350 °C.
Other criteria differentiating the units include:
- Units with direct or indirect cooling (separation of cooling and temperature control circuits by cooler).
- Units with bath heating or forced circulation system.
- Single or multiple-circuit units.
- Temperature control circuits differ in terms of main technical specifications, such as maximum outlet temperature, heat transfer fluid (water or oil), heating capacity, cooling capacity, pump capacity (flow rate and pressure).
There are 3 basic cases of heating and cooling:
- Heating to production temperature: The unit heats only.
- Production: Due to changes in the ambient temperature, cycle time, etc., the temperature of the consumer also changes. If it rises, the unit will cool; if it drops, the unit will heat.
- Production interruption: Generally, the consumer must be heated to prevent its temperature from dropping.
Method: Heating and cooling take place in on/off mode, i.e. either completely on or completely off. Due to its PD behaviour, the controller cycles, with heating or cooling pulses becoming shorter as the temperature nears its set point. Cycling prevents under and overshooting.
Because of the inertia of the control loop, on/off mode (cycling) provides the same control accuracy as control valves, for example, which are significantly more technically demanding and much more likely to break down. The controller is a three-step controller with the positions "heating - neutral - cooling".
The minimum required accessories consist of the following:
- A temperature and pressure-resistant hose for the outlet and for the inlet.
- Two hoses for the cooling water circuit.
- Power cable.
Additional accessories depend on the application involved.
Via a data interface. The digital interface (e.g. RS485) is preferable both technically and in terms of reliability.
Regloplas units provide about 38 different data transfer protocols for the transfer of data from the unit to the production machine. The choice of interface depends on the production machine in use. The machine's hardware and interface protocol of the machine must be compatible with the unit.
The set-up depends on production and space conditions. If, due to production conditions, the temperature control unit settings must be changed frequently, it makes sense to place the unit where it is easily accessible.
With regard to the distance of the temperature control unit from the production machine or consumer: Due to temperature and pressure losses in the connection lines between the unit and the consumer, the temperature control unit should be placed as close to the machine or consumer as possible. Due to pressure losses, the inner Ø of the feed hoses should not be reduced before the consumer.
Recommended value for the connection lines: inner Ø not less than the inner Ø of the inlet/outlet of the temperature control unit.
Distances greater than approximately 5 m should be avoided. If this is not possible, temperature drops and pressure losses in the feed hoses must be considered when setting up the temperature control unit. If the unit is used primarily for heating, the hoses should be thermally insulated.
Bringing a temperature control unit on line is very simple:
- Connect the hoses between the temperature control unit and the consumer.
- Connect the unit to the cooling water circuit.
- Connect the unit to the power supply.
- Turn the unit on at the main switch.
- Fill the heat transfer fluid (manually for thermal oil, manually or automatically for water, depending on model and version).
- Enter the outlet temperature/set-point value at the controller (corresponds roughly to the production temperature of the consumer).
- Turn on the unit (pump, heater, etc.).
- For manual filling, continue to fill the heat transfer fluid until the pump runs without interruption, i.e. sufficient heat transfer fluid is circulating in the temperature control circuit.
The steps listed above are described in detail in the Operating Instructions.
The theoretically lowest possible outlet temperature of a temperature control unit is the inlet temperature of the cooling water (for direct cooling). Practically speaking, however, the minimal outlet temperature must be at least 5 °C higher.
The reason for this is that a minimal temperature drop is necessary in order for heat exchange to occur between the cooling water and the circulating heat transfer fluid in the temperature control circuit (consumer circuit).
Yes. A temperature control unit's cooling capacity is strongly temperature dependent. The lower the set-point temperature selected, the lower the cooling capacity. See the unit-specific cooling-capacity graphs in the “Regloplas Temperature Control Engineering” brochure.
At operating temperatures above approximately 180 °C. The reasons for this are:
- Safety risks associated with systems not using fixed pipes. At 180 °C, the system pressure has already reached 12 bar, which does not include the pump pressure that depends on the consumer connected to the temperature control unit.
- The seals in the consumer can leak at these high pressures.
- Depending on the acceptable pressure of the consumer, the pressure in the temperature control circuit must be kept to a minimum.
- If no limits are present, water is to be preferred over oil as a heat transfer fluid due to water's significantly better heat transfer properties.
Basically, only oils specifically labelled as thermal oils may be used (e.g. hydraulic oils are not acceptable). The main criterion for the use of a thermal oil for a given temperature control unit is the maximum acceptable outlet and film temperatures provided by the manufacturer of the oil. Synthetic thermal oil should be used whenever possible.
No. Energy consumption depends upon the application. A few criteria include:
- Duration and number of heat-up phases (depends on: consumer weight, e.g. injection mould, number of consumer changes due to small series, production interruptions, etc.).
- Layout of the consumer (heating, cooling, or thermal equilibrium, i.e. practically neither heating nor cooling during production).
- Unit-specific criteria: Heat-insulation (“good” for heating, “poor” for cooling), pump efficiency (heat generation).
The only thing that can be said about the minimum energy consumption of a temperature control unit is that it is the sum of the power consumed by the pump motor and the control system.
As applications conditions have such a large influence (operating temperature, dusty environment, quality of the heat transfer fluid, dirt in the temperature control circuit (consumer, connection lines)), absolute answers aren’t possible.
The customer must use his experience to find the optimal cleaning interval himself. The Operating Instructions serve as a basis. In the “Maintenance/Service” section, you’ll find tips for necessary cleaning procedures/checks to be made on the temperature control unit.
Application conditions such as operating temperature, characteristics of the heat transfer fluid (quality of the water or oil), dirt in the temperature control circuit (consumer, connection lines), etc. play a very important role in this question. An absolute answer is therefore not possible.
Guidelines for water: Replace after about 2000 hours of operation, including additive. Guidelines for oil: Check after about 1000 hours and replace after about 2000 hours, including additive (= 1 year in 1-shift operation).
One factor in judging whether a temperature control unit is functioning properly is the temperature. Set-point and actual temperatures must correspond (±1 to ±2 °C). If this is not the case, the unit is not operating properly.
If cooling remains on continuously and the actual temperature nevertheless remains too high, either the unit is too small for the application, or one of the following problems may exist: the cooling water connection is closed; the cooler is coated with scale; or the filter in the cooling water network is dirty.
Possible causes of insufficient temperatures: heater, heat contactor, or solid-state relay is defective; or the solenoid valve for the cooler does not close properly, causing water to flow through the cooler continuously. If the actual temperature oscillates about the set-point value due to incorrect setting of the control parameters (alternating heating and cooling), energy is wasted and stress on the unit increased.
As the temperature is usually measured in the medium (water or oil), agreement between the set-point and actual temperatures displayed does not necessarily mean that the consumer temperature is being controlled properly. If the flow rate is insufficient, the temperature will not be transferred to the consumer fully. Therefore, the flow rate must also be checked which can be done using a built-in or external flow meter.
As a rule, yes.
However, this depends greatly on the repair skills of the company in question; i.e. does it have a maintenance department with qualified employees?
Yes. Regloplas has compiled a number of checklists to determine the correct temperature control unit. Send a request for more information.