Pilot operated safety valve

Abstract

The invention relates to a pilot operated safety valve which comprises a main valve and a pilot valve, the pilot valve is communicated with the main valve to control opening of the main valve, the pilot valve comprises a pilot valve body and a pilot valve clack assembly, and a medium inlet, an air chamber outlet and a pilot valve outlet are formed in the pilot valve body. The pilot valve clack assembly is movably arranged in the pilot valve body to control whether the air chamber outlet is communicated with the medium inlet or not, and the pilot valve further comprises a rupture disk arranged in the pilot valve body. The rupture disk controls the air chamber outlet to be communicated with the pilot valve outlet and the medium inlet or not and limits the moving distance of the pilot valve clack assembly. The rupture disk and the pilot operated safety valve are combined, and the advantage of good sealing performance of the rupture disk structure is utilized, so that good sealing of media is achieved, and meanwhile action control over the main valve is achieved through the pilot valve.

Description

technical field [0001] The invention belongs to the technical field of valves, and in particular relates to a pilot safety valve. Background technique [0002] The pilot-operated safety valve generally includes a main valve and a pilot valve, and the action of the main valve is controlled by the opening and closing of the pilot valve. The pilot valve in the existing pilot-operated safety valve uses spring force to achieve sealing. As the operating pressure increases, the sealing effect of the pilot valve gradually decreases. When the medium pressure is close to 90% of the set pressure, the pilot valve will inevitably leak (The main valve structure achieves sealing under the effect of sealing area difference, the higher the medium pressure, the better the sealing performance). For toxic, flammable and explosive medium conditions, medium leakage may cause harm to personnel and the environment. [0003] The use of the bursting disc structure can provide safety protection befo...

AI Technical Summary

Problems solved by technology

However, the rupture disc structure used in the large-diameter, high-pressure system is difficult to manufacture, and the price is high, and the cost of use is high; secondly, the rupture disc structure can only be replaced after the medium is cut off through the upstream pipeline or the medium is emptied

However, it is difficult to quickly cut off large-diameter and high-pressure pipelines. Before the complete cut-off is achieved, a large amount of medium will be released quickly, which may cause waste of medium and other hazards. In addition, the replacement cost of large-diameter rupture discs is high

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