The principle of operation of a direct-acting temperature regulator

The principle of operation of a direct-acting temperature controller is based on the use of the thermal expansion energy of the liquid in a closed circuit. The closed circuit is formed by the cavity of the temperature sensor connected by an impulse tube to the thermoplastic bellows. Depending on the range of adjustment, the working fluid that fills the bellows and the sensor can be a liquid, gas, paraffin or gas-liquid mixture.

The temperature sensor is installed at the temperature maintenance location. When heated, the volume of the working fluid increases, and when cooled, it decreases. The change in volume in the closed cavity (sensor-impulse tube-thermoplastic bellows) leads to a change in pressure.

With increasing pressure, the thermoplastic bellows extends, presses on the valve stem, changing the position of the shutter and automatically reducing the flow rate through the temperature controller. When the water temperature decreases relative to the set value, the pressure in the bellows decreases, compressing it and raising the temperature controller stem.

According to the reaction to an increase in water temperature, regulators are divided into those that open with increasing temperature and those that close. Each actuator regulates the temperature in a certain range.

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