Backpressure-adjusting pilot operated safety valve

Abstract

The invention relates to a backpressure-adjusting pilot operated safety valve. The backpressure-adjusting pilot operated safety valve comprises a main valve and a pilot valve; the main valve comprises a main valve body, a main valve seat, a main valve flap and a main valve bonnet; the pilot valve comprises a pilot valve body, a pilot valve seat, a pilot valve flap, a pilot valve bonnet and a pressure adjusting device, wherein a pilot valve body inlet channel is communicated with a main valve body inlet cavity through a pipe fitting. The backpressure-regulating pilot operated safety valve is mainly characterized in that a flow limit hole communicating a main valve backpressure cavity with the pilot valve body inlet channel is formed in the side wall of the pilot valve seat, a pilot valve outlet cavity is communicated with a discharge cavity of the main valve body through a discharge channel, the discharge channel, the pilot valve body inlet channel and a pipe fitting outlet channel form a three-way channel, a three-way valve is arranged in the three-way channel, one end of a three-way valve flap is provided with a seal surface mutually matched with the end opening of the pipe fitting outlet channel, the other end of the three-way valve flap is provided with a seal surface mutually matched with the end opening of the discharge channel, and the outer circumferential surface of the three-way valve flap is in clearance fit with the inner cavity wall of the pilot valve body. The backpressure-adjusting pilot operated safety valve can prevent a medium contained in the discharge cavity from flowing backwards and has the advantages of being good in backflow preventing property, reliable in reverse sealing property and the like.

Description

technical field [0001] The invention relates to the field of valves, in particular to a pilot safety valve. The invention is suitable for a pressure vessel or a pressure pipeline in a high back pressure working condition where the discharge pressure is close to the set pressure. Background technique [0002] Pilot-operated safety valve, including the main valve and pilot valve, controls the opening and closing of the main valve through the opening and closing of the pilot valve. The working mode of the pilot valve is mainly a spring direct load structure, and the flow mode is non-overflow type. , its disadvantages are: when there is a high back pressure at the outlet, the medium is prone to backflow, and the reverse sealing is poor. Contents of the invention [0003] The object of the present invention is to aim at the shortcomings of the prior art, and to provide a back pressure regulating pilot safety valve with good backflow prevention performance and good reverse seal...

AI Technical Summary

Problems solved by technology

[0002] Pilot-operated safety valve, including the main valve and pilot valve, controls the opening and closing of the main valve through the opening and closing of the pilot valve. The working mode of the pilot valve is mainly a spring direct load structure, and the flow mode is non-overflow type. , its disadvantage is: when there is a high back pressure condition at the outlet, the medium is prone to backflow, and the reverse sealing is poor

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