| 摘要 |
A safety valve for relief of overpressure, comprising: a body (12; 112) delimiting an internal duct or space (13; 113) for communication with a fluid system on which a safety control is to be provided; a shell (16; 116) of said body, the said shell having a discharge orifice (23; 123), an opening (22; 122) for communication with the internal duct of the said body, the said opening communicating with an inner chamber of the shell, the said chamber being delimited by a bottom plate (18; 118) provided with a hole; a spring-biased main shutter member (50; 150), slidably received within the chamber of the shell, the said member being movable between a closing position, in which it exposes a part of the head to the pressure of the fluid in the duct, and an opening position, in which it exposes to the pressure of the fluid a number of surfaces, the said number of surfaces of the shutter member having differentiated areas so that the area of the main shutter member exposed to fluid pressure in the valve closed position is different from the area of the main shutter member exposed to fluid pressure in the valve open position. <IMAGE> |
