How Surface Safety Valve works?

When the steam pressure under the safety valve disc exceeds the compression force of the spring, the valve disc is pushed open. After the valve disc is opened, the discharged steam acts on the disc clamping ring due to the rebound of the adjusting ring, which makes the valve open quickly. The steam is continuously discharged, and the steam pressure in the system is gradually reduced. At this time, the spring force will overcome the steam pressure acting on the disc and the reaction force of exhaust steam, thus closing the safety valve