The spring-loaded relief valve is mainly composed of the valve core, seat, stem, spring, adjustment screw, etc. This kind of relief valve mainly uses spring elastic force to press the valve core on the seat. When the boiler pressure exceeds the pressure of the spring action on the upper part of the valve core, the valve core and stem are raised and the steam is discharged, and when the boiler pressure is lower than the pressure that the spring acts on the upper part of the valve core, the valve core falls on the seat and the boiler stops the discharge.
The contact surface of the valve core and the seat is a cone surface with a slight outstretch on the edge around the valve core. When the steam top open valve core, the edge of the valve core is also subject to the action of vapor pressure, so that the entire action area suddenly increased, the safety valve suddenly opened; The main parameters of the spring-loaded relief valve are the opening pressure and discharge capacity, which depends on the diameter of the seat and the lift height of the valve core. Due to the different height of lift, it can be divided into micro-open type, medium-open type and full-opening safety valve three.
The spring-loaded safety valve is compact, small and light, tight, and easy to adjust, and can withstand vibration, and there is little leakage. As a result, it is sensitive and reliable. It is the most widely used and is the most commonly used.