What are the main structures of pressure limiting valves?

The pressure limiting valve is generally composed of a valve body (vertebrae, spherical), a valve seat, a regulating spring, a pressure regulating screw and a locking nut, and a sealing washer. The working principle of the pressure limiting valve is: in most of the time, the pressure limiting valve is closed, only when the pressure of the working medium exceeds a certain value, the pressure limiting valve is opened, and a part of the medium is discharged from the bypass to reduce the pressure in the system; When the pressure of the system reaches the lower limit, the pressure limiting valve is closed and the pressure of the system rises again.