safety valve

I still don’t understand how to make the adjustments

That isn’t a adjusting nut at all; the adjusting nut is located above the spring. This is rather a screw used to fix the adjusting ring. The gear-like component visible in the photo is the adjusting ring, and the screw serves to secure it by fitting into the gears of that ring. There is not necessarily just one such adjustment ring; it is used in high-precision safety valves, where upward and downward adjustments are made to change the force-bearing area of the valve core.

Simply put, it involves adjusting the return pressure and discharge pressure of the safety valve.

This diagram is not well-made; those who don’t understand it will find it even harder to comprehend.

Can’t understand it, let’s move on. For safety valves whose opening pressure has been adjusted, if the discharge pressure or return pressure does not meet the requirements, it is possible to make adjustments by changing the position of the adjusting ring. Safety valves come in two types: those with a single adjusting ring and those with a double adjusting ring (Figure 1, Figure 2). For safety reasons, before making adjustments, the pressure at the valve inlet should be reduced appropriately (generally to less than 60% of the opening pressure), in order to prevent the valve from opening suddenly during adjustments and causing accidents. The test bench used to adjust the discharge pressure and reset pressure must have an adequate flow rate of air supply, so that testing can be carried out only when the valve is fully open (i.e., at the full opening position of the safety valve); otherwise, the values measured for the discharge pressure and reset pressure will be inaccurate

Just take a look when adjusting the safety valve and you’ll know:D It’s simple and clear