A low pressure differential opening check valve

Abstract

The invention discloses a low drop-out starting check valve. The low drop-out starting check valve comprises a valve body, a valve seat, a valve clack, a rocker arm, a rocker arm shaft, an indicating stem, a permanent magnet, a valve cover and a sensor, wherein an angle at 3 degrees is formed between a sealing surface of the valve clack which is in contact with the valve seat and a vertical direction, so as to realize that the valve can be started in a low pressure difference environment and the leakproofness of the check valve can be taken into account. The valve clack is of a semispherical structure, so as to be beneficial for starting the valve clack. When the valve clack is pushed to drive the rocker arm to rotate along a rock arm shaft to start and close by a medium, and the rocker arm supports and drives the indicating stem to move up and down, therefore a permanent magnet arranged at the top end of the indicating stem and a sensor arranged on the valve cover can be mutually sensed to sense a signal, the signal is output to a remote computer through an external cable so as to react the on and off positions of the valve clack. According to the low drop-out starting check valve provided by the invention, the valve can be started in the low pressure difference environment, and the on and off states of the valve can be safely, effectively and remotely monitored.

Description

technical field [0001] The invention relates to a low-pressure differential check valve used on a containment recirculation line in a CAP1400 passive core cooling system of a nuclear power plant. Background technique [0002] According to the original design of AP1000, the check valve at the outlet of the replacement material tank in the containment and the check valve on the recirculation pipeline of the containment are conventional swing check valves, which rely on the medium gravity to inject water into the core. However, since the swing check valve needs to overcome the gravity of the disc itself when it is opened, when the liquid level of the replacement material tank in the containment gradually decreases (the check valve on the recirculation pipeline only replaces the liquid level of the material tank in the containment) After it drops to a certain level before opening), the driving force to push the valve to open gradually becomes smaller, which may eventually cause ...

AI Technical Summary

Problems solved by technology

However, since the swing check valve needs to overcome the gravity of the valve disc itself when it is opened, when the liquid level of the refueling water tank inside the containment gradually drops (the check valve on the recirculation pipeline is only when the liquid level of the refueling water tank inside the containment After falling to a certain level before opening), its driving force to push the valve to open gradually decreases, which may eventually cause the valve to fail to fully open or even fail to open.

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