FAQ – Frequently asked questions

Generally speaking, any application where a consumer (die, roller, container, etc.) connected to the temperature control unit needs to be heated up to a specific production temperature and then held at this temperature through heating and cooling. The consumer also needs to have the appropriate bores/channels for the circulation of water or a heat transfer oil.

The number of different areas of application and possibilities for Tool-Temp temperature control units is huge.

They serve two basic functions
The first is the heating phase in which heat is provided to the consumer. Consumers can be tool dies, rollers, containers, reactors, etc. that need to be brought to a very specific temperature for a particular production process.

The second phase is maintaining the temperature of the consumer at the optimum production temperature. This must be maintained regardless of production conditions such as interruptions or changes to the cycle time.

With a temperature control unit from Tool-Temp:

• You can optimise your production time
• You can guarantee and ensure a high and consistent quality for the product you produce

• Maximum inlet temperature
• Heat transfer medium
• Heating capacity
• Cooling capacity
• Pump capacity (flow rate/pressure)
• Connection current
• Internal system structure

Temperature control units are divided into water-based units and units that operate using heat transfer oil (or glycol). The process thermostat, i.e. temperature control units, using water generally have a max. inlet temperature of 90°C and 160°C for pressurised water units. Oil-based units can handle up to around 360°C.

Further criteria for differentiating units are:

• Units with direct or indirect cooling (separation of cooling and temperature control circuits with an intermediate cooler).
• Reservoir heating or forced circulation.
• Single and multi-circuit units.

Further features that differ between units are:

• Maximum inlet temperature
• Heat transfer medium used – water or oil
• Heating capacity
• Cooling capacity
• Pump capacity
• Flow rate
• Pressure

There are 3 different operating states:

• Heating
• Cooling
• Maintaining

1. Phase one – heating
   Heating up to production temperature The temperature control unit heats until the desired ‘initial temperature’, or starting temperature, is reached.
2. Phase two – production
   During this phase, the unit switches between heating and cooling modes. Due to changing and non-constant conditions during production, e.g. ambient temperature fluctuations, cycle time, etc., the temperature of the connected consumer also changes. In the temperature gets too high, the control units starts cooling. If the temperature falls below a set value, then the unit starts heating.
3. Phase three – production interruption – maintain

The consumer is at its optimum temperature and there is an interruption in the production process. During an interruption, the consumer generally needs to be heated to prevent its temperature from dropping and allow production to resume more quickly.

Fundamental principles of heating and cooling
Heating and cooling is done using on/off operation – it is either fully on or fully off. Due to its PD action, the controller pulses between states. The heating and cooling pulses are shorter the closer the temperature is to the target value. This pulsing prevents exceeding or falling below the target.

Control circuits are by their very nature ‘sluggish’. This sluggishness means that this kind of on/off operation can achieve the same degree of precision as e.g. a relay valve, which would require significantly more technical effort to design and build. The controller is three-step controller with the following settings: Heat – maintain – cool.

Connection and technical installation depends on the process conditions within the system. The following basic components for the basis of the installation:

• A hose for the inlet and a hose for the return.
• These hoses must be resistant to both temperatures and pressure.
• Two hoses for the cooling water system.
• A power supply cable.
• Further equipment depends on the application.

This is generally possible using a data interface. A digital interface (e.g. RS485) should be preferred, both from a technical and reliability point of view. Tool-Temp supports a variety of different interface protocols for transferring data between unit and machine. Which interfaces are used depends on your production machine. The interface protocol and machine hardware must be compatible with the unit.

• How the unit is installed depends on the production system and available space. If production conditions require the configured values on your temperature control unit to be changed often, then it is worth positioning the unit in an easy to access location.
• The following must be considered with regards to the distance of the temperature control unit from the consumer: Due to the temperature and pressure losses in the connecting lines between the temperature control unit and the consumer, the temperature control unit should be placed as close to the machine / consumer as possible. Due to pressure losses, the inner diameter of the supply lines should be reduced no earlier than at the point the line reaches the consumer, if it must be reduced at all.
• Recommended values for connecting lines: Inner diameter no smaller than the inner diameter of the inlet/return flow on the temperature control unit.
• Distances greater than approx. 5 m should be avoided. If this is not possible, the losses in temperature and pressure in the connecting lines must be considered when configuring the unit.
• Where heat is primarily being supplied, the lines should have appropriate insulation. This helps to reduce costs.

• Both of these terms describe the same function.
• A temperature control unit is a process thermostat, and vice-versa.
• Depending on the sector, these types of device can have different names, but are one and the same thing. The term ‘process thermostat’ is often used in the chemical and pharma industries.

Setting up a temperature control unit is very simple:

• Install the connection and hose lines between the temperature control unit and the consumer.
• Connect the temperature control unit to the cooling water supply.
• Connect the unit to the electrical power supply.
• Switch on the unit with its main switch.
• Fill the unit with the heat transfer medium (oil units are filled manually, water units are filled either manually or automatically depending on model and variant).
• Enter the inlet temperature, target value on the controller (corresponds more or less to the production temperature of the consumer)
• Switch on the temperature control unit (pump, heating, etc.).
• If filling is not automatic, continue adding the heat transfer medium until the pump runs continuously without interruptions, i.e. there is sufficient heat transfer medium circulating in the temperature control circuit.
• Each of these steps is described in detail in the Tool-Temp operation manual.

• The theoretical lowest inlet temperature on a temperature control unit corresponds to the inlet temperature of the cooling water (if using direct cooling). In practice however, the minimum inlet temperature should be set at least 5°C higher.
• Reason: To ensure that heat can be exchanged between the cooling water and the circulating heat transfer medium in the temperature control circuit (consumer circuit), the temperature drop must be minimal.

Yes. Cooling capacity is heavily dependent on temperature. The lower the target temperature (inlet temperature), the lower the cooling capacity.

This is recommended for operating temperatures above approx. 180°C.

The reasons

• There is a safety risk where piping does not use continuous solid piping connections. At 180°C, the system pressure is already at 12 bar. This is in addition to the pump pressure of the connected consumer.
• Seals in the consumer may leak if the pressure is too high.
• Depending on the consumer’s permitted pressure, the pressure in the temperature control circuit itself must be as low as possible.

General

• There are no limitations. Due to the much better heat transfer properties of water compared to oil, water should be preferred as the heat transfer medium wherever possible.

• Only oils that have been specifically certified by the manufacturer as heat transfer oils should be used.
• The most important criteria for using a heat transfer oil in a temperature control unit is the maximum permitted inlet and film temperatures as specified by the manufacturer.
• Synthetic heat transfer oils should be used wherever possible.
• Important: Hydraulic oils cannot be used.
• Do not use oils that are not labelled as suitable for this purpose.

The energy consumption of a temperature control unit depends on the specific application and is determined by the consumer. I.e. there are no reference values for actual energy consumption. A small, supposedly affordable temperature control unit can consume large amounts of energy if the system/consumer ‘sucks’ up too much and the temperature control unit is not sufficiently powerful and is constantly overloaded.

A few important criteria:

• The duration of the heating phase and the number of heating phases. However, this is also dependent on: the weight of the consumer, e.g. the injection moulding die, the number of consumer changes due to small batch production and any interruptions in production.
• The design of the consumer (heat supply and removal or thermal balance, i.e. practically no need for heating or cooling during production).
• Unit-related criteria: Thermal insulation (‘good’ for heating, ‘bad’ for cooling).
• Unit-related criteria: Pump efficiency (heat build-up).

Only generalised statements can be made about minimum energy consumption, which is determined by the power consumption of the pump motor and the controller. When selecting a temperature control unit, we recommend sending us the performance data so that we can made dimensioning recommendations.

• The prevailing operating conditions greatly influence how often cleaning is required. No concrete information can be provided here.
• The factors influencing the cleaning interval are: Operating temperature, dusty atmosphere, quality of the heat transfer medium, contamination of the temperature control circuit, consumer and/or within the connecting lines.
• The operator of the unit is responsible for determining an optimal cleaning interval, as they know their processes and production methods best.
• The information in the Tool-Temp operation manual can provide a basis for making a determination. There you will find information about the cleaning activities required and what checks to perform on your temperature control unit.

This primarily depends on your production conditions and also whether you operate in shifts and the number of operating hours.

Key criteria are the operating conditions such as operating temperature, properties of the heat transfer medium (quality of the water or oil), contamination in the temperature control circuit (consumer, connecting lines). It is therefore not possible to provide any precise, specific data on replacing the heat transfer medium.

Guidelines for water
Replace water incl. additives every 2000 operating hours.
This value represents one year with single shift operation.

Guidelines for oil
Check after approx. 1000 hours and replace incl. additives every 2000 hours. This value represents one year with single shift operation.

The temperature can indicate whether or not a unit is functioning properly. The target and actual temperatures must be the same (±1 to ±2°C). If this is not the case, then there is a problem with the temperature control unit.

If the actual temperature is too high despite cooling mode being active, then either the unit is not powerful enough or one of the following problems may be present:

• Cooling water line closed.
• Limescale has built up in the cooler.
• The cooling water filter is dirty.

Possible causes of temperatures that are too low:

• Heating is defective.
• Heating power contactor is defective.
• The solid state relay is defective. The solenoid valve for cooling is not closing correctly so that water is continuing to flow through the cooler.

If the control parameters have been set incorrectly so that the actual temperature oscillates around the target temperature value (switching between heating and cooling), this can cause unnecessary energy consumption and put increased loads on the temperature control unit. Since the temperature is usually measured in the medium (water or oil), the fact that the target and actual temperature values displayed on the controller are the same, does not necessarily mean that the temperature of the consumer is being controlled properly.

If the flow rate is insufficient, the consumer will not be controlled at the required temperature. The flow rate must therefore be checked. This can be done using an integrated or external flow meter.

Basic repairs can generally be done yourself. However, this very much depends on the ‘standard of repair’ and the knowledge and skills available within your company: Do you have e.g. a servicing or maintenance department with appropriately trained people?

The most important measures to protect your equipment: Always clean units thoroughly before undertaking any repairs. Regular cleaning of the tank and simple cleaning of the interior of the unit will lengthen the service life.

Read and make use of the Tool-Temp operating instructions for your temperature control unit.

If anything is unclear, please get in touch with us and we will do our best to help.