1. Core structure and driving mechanism Main assembly It consists of valve body, valve cover, valve disc, valve stem and electric actuator. The valve body is made of high temperature resistant alloy materials (such as stainless steel and chrome-molybdenum steel) to ensure structural strength under high temperature and high pressure. The valve disc is connected to the electric actuator through the valve stem. Its motion trajectory is a linear motion perpendicular to the valve seat sealing surface. The medium flow is controlled by adjusting the gap between the valve disc and the valve seat. Power transmission The electric actuator receives the control signal (such as 4~20mA or switch quantity instruction), drives the motor to drive the valve stem to rotate, and converts it into the vertical lifting action of the valve disc through the gear or screw mechanism. The valve disc stroke is linearly related to the flow rate. When the valve disc opening height reaches 25%~30% of the nominal diameter, the flow rate reaches the maximum value, and the valve is in the fully open state.
2. Special design for high temperature environment
Forced sealing mechanism
When closing, pressure needs to be applied to the valve disc to force it to fit with the valve seat sealing surface. The medium pressure enhances the sealing effect (especially when the medium flows from top to bottom).
Under high temperature conditions, the valve seat and valve disc are made of carbide or surfacing Stellite material to prevent thermal expansion from causing sealing failure.
High temperature resistance measures
The valve stem is sealed with graphite packing or bellows to reduce thermal stress and medium leakage risks caused by high temperature.
The actuator has a built-in heat dissipation structure (such as heat sink or cooling fan) to ensure stable operation of the motor and electronic components in high temperature environment.
3. Control and feedback process
Signal processing and action response
The control system sends instructions to the electric actuator, and the actuator analyzes the signal through the built-in logic circuit to drive the motor to adjust the valve disc position.
When equipped with a positioner, it can receive continuous signals (such as 4~20mA) to achieve precise opening adjustment, with an error range of ≤±1%.
Closed-loop feedback mechanism
The valve disc opening is monitored in real time through the position sensor, and the data is fed back to the control system to form a closed-loop control, improving the adjustment accuracy and response speed.