Working Principle and Classification of Thermal Control Valve

Working Principle and Classification of Thermal Control Valve

Thermostatic balancing valve is a typical application of flow control valve in the field of temperature control. Its basic principle is to control the outlet temperature of equipment by controlling the inlet flow of heat exchanger, air conditioning unit or other heat, cooling equipment and primary heat (cold) medium. When the load changes, the flow rate can be adjusted by changing the opening degree of the valve to eliminate the impact of load fluctuation and restore the temperature to the set value. The self-operated thermal control valve realizes automatic regulation by using the principle of liquid thermal expansion and incompressibility. The liquid expansion in the temperature sensor is uniform and its control function is proportional adjustment. When the temperature of the controlled medium changes, the volume of the temperature-sensitive liquid in the sensor expands or shrinks. When the temperature of the controlled medium is higher than the set value, the temperature-sensitive liquid expands, pushing the valve core down to close the valve, reducing the flow of heat medium; when the temperature of the controlled medium is lower than the set value, the temperature-sensitive liquid shrinks, and the reset spring pushes the valve core open, increasing the flow of heat medium. Electric thermal control valve is a typical application in the field of temperature control such as HVAC. The controller has PI and PID adjusting function, precise control, multi-loop control and various functions. It can realize the control of fluid flow, pressure, differential pressure, temperature, humidity, and enthalpy and air quality. The actuator has electro-mechanical and electro-hydraulic type, with manual and automatic adjustment function, sensitive adjustment, large turn-off force, adjustable flow characteristics (linear equal percentage). The electro-hydraulic actuator has the function of automatic reset protection with power off. It can receive signals of 0-10V or 4-20MA and has the function of valve position feedback. The valve body is a flow regulating valve. It is suitable for the regulation of refrigerated water, low pressure hot water, domestic hot water, high pressure hot water, seawater, hot oil and steam in circulation pipeline. It has good linearity, large adjustable ratio, tight seal, high temperature resistance and anti-cavitation.  
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