Pressure safety valve

The invention discloses a pressure safety valve. The safety valve comprises a valve body, wherein a first chamber is formed by a first one-way valve core and the front part of an inner hole of the valve body in a surrounding manner, a second chamber is formed by the first one-way valve core, the front end of a push rod and the inner hole of the valve body in a surrounding manner, third chambers are formed by the middle part of the push rod and the inner hole of the valve body in a surrounding manner, and a fourth chamber is formed by the back end of the push rod and the back part of the inner hole of the valve body in a surrounding manner; second oil holes are formed in the valve body and in positions corresponding to the first one-way valve core, third oil holes are formed in the valve body and in positions corresponding to the front part of the push rod, fourth oil holes are formed in the valve body and in positions corresponding to the third chambers, and a fifth oil hole is formed in the valve body and in a position corresponding to the fourth chamber; the second oil holes and the fourth oil holes are connected with an oil tank, the third oil holes are connected to a hydraulic system in parallel, and the fifth oil hole is an oil outlet; pressure maintenance structures which are used for maintaining the balanced pressure of the push rod are arranged in the third chambers and the fourth chamber. The safety valve disclosed by the invention can prevent pressure impact, prevent equipment from being damaged and improve the security of the equipment.