How the Self-acting temperature regulator works

Self-acting temperature regulator is designed to automatically maintain the set temperature at the location of the temperature sensor. Temperature control is achieved by partially or fully shutting off the flow with the regulating valve. The temperature regulator operates without external power sources.

Principle of operation of the thermostatic regulator is based on the use of thermal expansion energy of a substance in a closed circuit. The closed circuit consists of the cavities of the temperature sensor and the bellows of the thermal actuator. The bellows is connected to the temperature sensor via an impulse tube.

The regulator sensor is installed at the temperature control point. The substance inside the temperature sensor and the thermal actuator heats up and expands as the temperature increases. This expansion increases the pressure inside the bellows, causing it to extend. The bellows pushes the valve stem, gradually moving it from a fully open to a fully closed position.

When the water temperature drops below the set value, the pressure inside the bellows decreases, and it contracts. During cooling and compression of the bellows, the stem rises due to the force of a spring, which is designed to open the regulator valve.

The working medium filling the bellows and temperature sensor can be a liquid, gas, paraffin, or a gas-condensate mixture. The physical properties of the working medium affect the temperature range in which the thermal actuator can regulate temperature.

During operation, the regulator shutter can be fully open, fully closed, or partially open.

Based on the reaction to increasing water temperature, regulators are divided into those that open as temperature rises and those that close. Regulators that close when the temperature increases are called normally open because, before reaching the set temperature, the regulator shutter remains open.

Thermostatic temperature regulators are also called 'self-acting regulators' because the valve shutter movement occurs without external power sources.

Proportional regulators are so named because the speed and degree of valve shutter movement are proportional to the speed and degree of temperature deviation at the sensor location from the set value.