The spring relief valve is mainly composed of spool, seat, stem, spring and adjusting screw.The relief valve mainly USES spring force to press the spool on the seat.When the boiler pressure exceeds the pressure exerted by the spring on the upper part of the spool, the spool and stem are lifted and steam is discharged.When the boiler pressure is lower than the spring pressure acting on the upper part of the spool, the spool falls on the seat and the boiler stops discharging steam.
The spool is a cone with a slight protrusion around the edge of the spool.When the steam opens the valve core, the edge of the valve core is also affected by steam pressure, which makes the whole area of action increase suddenly, and the valve opens when the valve stops.When the drop force is reduced, the steam force suddenly decreases, making the valve core close once and preventing the valve core from beating repeatedly.The main parameters of the spring relief valve are opening pressure and exhaust capacity, which depends on the size of the seat and the lifting height of the spool.Due to different elevations, it can be divided into three types: micro-open, medium-open and full-open safety valves.
The spring safety valve is compact, small and light.Good tightness, and easy to adjust, can withstand vibration, leakage phenomenon is rare.Therefore, sensitive and reliable.It is the most widely used one.