Termostater
Technische Features im Überblick
Mechanische Thermostate
- Regelung und Überwachung von Temperaturen von bis zu 650 °C ohne Hilfsenergie
- Gehäuseausführungen für Wandaufbau und zur Montage hinter einem Panel
- Sehr robuste Systeme hinsichtlich mechanischer Belastung und EMV-Störungen
- Ausführungen als Sicherheitsgeräte (STB und STW) nach DIN EN 14597
- Varianten zur Platzierung im Ex-Bereich
- OEM-Ausführung möglich
Elektronische Thermostate
- Anschluss von Widerstandsthermometern und Thermoelementen
- Regelung der Temperatur durch Ansteuerung einer Heizung/Kühlung über Binärausgang
- Anpassung auf die Anwendung über die Gerätefront und über ein Konfigurationsprogramm
- Unterschiedliche Formate zum Einbau in eine Fronttafel und Ausführung zur Montage auf C-Schiene
- Ausführung als Kühlstellenregler (mit Abtaufunktion) und viele Zusatzfunktionen
- OEM-Ausführung möglich
Buy an industrial thermostat
The most important background information
A very precise control result is achieved with temperature controllers. These measure the temperature with a temperature sensor and, as PID controllers, they regulate the temperature exactly to the setpoint value. In the case of binary control, precise adjustment is possible by changing the relative switch-on time of the actuator. For example, the heat output can be varied from 0 to 10 kW.
In contrast, temperature switches are assigned to the discontinuous two-state controllers – the process temperature fluctuates with them around the setpoint value. In many applications, such temperature fluctuations are acceptable, so that temperature switches can be used to set up very robust temperature control at low cost.
As the name suggests, a bimetal is used in bimetal switches. The 2 metals that are rolled onto each other (e.g. copper and nickel) have different expansion coefficients. As the temperature rises, the metals expand to different degrees so that a deflection occurs and a contact is opened (NC) or closed (NO).
Bimetal switches in industrial environments have a very compact design and are usually screwed into the process like a sensor. Their switching point is fixed during production. They are also very resistant to vibration – a vibration resistance of up to 10 g is not uncommon. The switches are connected in the direction of the evaluation system via a connection line. Temperature switches with a bimetal are used in such devices as compressors – they switch off the compressor in the event of excess temperature or start active cooling (e.g. fan).
This type of temperature switch is usually referred to as a thermostat and consists of a probe filled with a gas or liquid that is placed in the process. If the temperature at the probe rises, the system pressure increases. Because the membrane is connected to the sensor via the capillary line, the same pressure is created in it. The membrane expands and a snap-action switch is triggered. The inner diameter of the capillary line with 0.2 mm is just twice the diameter of a human hair (up to 0.1 mm).
The probe and the thermostat housing are connected to each other via the capillary line. Maximum capillary line lengths of up to 5 m can be regarded as practical. The switching point can usually be set on the housing.