Overview and introduction to temperature control units
This article provides a clear overview of temperature control units (also called heating-cooling units) and where they are used. Temperature control units are used wherever a consumer must be controlled to a specific temperature via a heat transfer medium or different temperature levels must be reached cyclically via cascade control. Typical consumers include die casting and injection molds, dies, calendars and rollers, across industries such as die casting, plastics, pharma, chemical and food.
Important prerequisites for operation
For reliable operation, the temperature control channel bores in the consumer must be free of contamination (e.g. corrosion products, calcification). Dead zones should be avoided, as there is hardly any heat transfer there and contamination can accumulate. The supply lines between the temperature control unit and the consumer must be absolutely tight, insulated and secured against unintentional loosening – always designed for the maximum temperature and pressure range of the unit.
Necessity of filtration systems
To protect the temperature control unit, filtration of the pumped medium in the flow and return is essential. Common impurities (corrosion residues, metal chips, sand, cracked oil) lead to increased pump wear and even failure.
Heat exchange, media and cooling systems
Heat exchange takes place via the heat transfer medium. Heating is performed electrically via tubular heaters in application-specific power stages. A reduction in temperature can be achieved via direct or indirect cooling, e.g. with cooling coils or plate heat exchangers – directly in the circuit or in the bypass.
Control and process adaptation
The temperature control unit detects downtimes and the associated heat losses and compensates for them. Alternatively, the temperature can be controlled via the flow rate: The flow rate of individual temperature control circuits is monitored and adapted to the process, e.g. via servo valves. Where valves are to be dispensed with, control can take place via frequency-controlled pumps.
Integration into higher-level systems
Integration into higher-level machine control systems is possible in many cases, including centralized visualization, monitoring and documentation. Common interfaces include OPC UA, Profinet and Profibus.