A high-precision external exhaust pilot valve

Abstract

The invention discloses a high-precision external exhaust pilot valve, which belongs to the technical field of valves and includes a valve body and a valve cover. A control cavity and a pressure relief cavity are arranged inside the valve body, and the control cavity and the pressure relief cavity are connected through a conduction hole. The valve body is provided with a control chamber port connected with the control chamber, the bottom of the pressure relief chamber is provided with a valve front port, and a conduction valve sleeve is slid in the pressure relief chamber, the lower end of the conduction valve sleeve communicates with the front port of the valve, and the conduction valve There is a reset part on the sleeve, and a valve stem slides in the conduction hole. The lower end of the valve stem is opposite to the through hole in the middle of the conduction valve sleeve. There is a gap between the valve stem and the side wall of the conduction hole. The movable control component that controls the reciprocating movement of the valve stem through the pressure behind the control valve further improves the sensitivity and precision of the pilot valve control compared with the existing technology, and at the same time avoids the upper control chamber of the control valve and the rear of the control valve. The air balance self-locking occurs due to the end connection, and compared with the existing pilot valve, it can realize full-way opening without pressure difference between the front end of the control valve and the rear end of the valve.

Description

technical field [0001] The invention relates to the technical field of valves, in particular to a high-precision external discharge pilot valve. Background technique [0002] The self-operated control valve is a control valve that relies on the pressure and temperature of the medium flowing through the valve itself to drive the valve to work automatically, without external power supply and secondary instruments. Existing control valves are divided into direct-acting control valves and indirect-acting control valves according to their operating principles. Self-operated control valves with indirect control generally need to add a pilot valve. The pilot valve can amplify the feedback signal, and then through the actuator Drive the disc movement of the control valve to achieve the purpose of changing the valve opening. The control accuracy of the existing pilot valve is low. When used with the control valve, the control valve is more likely to have the problem of air balance s...

AI Technical Summary

Problems solved by technology

The control accuracy of the existing pilot valve is low. When used with the control valve, the control valve is more likely to have the problem of air balance self-locking. The main valve is always fully open and cannot be closed. In order to avoid the problem of air balance self-locking, the control valve There needs to be a pressure difference of 1 bar between the front end of the valve and the rear end of the valve, so a set of springs must be installed on the disc of the main valve for decompression, and the control valve cannot realize full-way opening without pressure difference

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