I want to know the working principle of this type of valve

When the master cylinder piston moves downward, the oil pump supplies less oil; the piston descends due to its own weight, creating a vacuum in the upper chamber of the master cylinder. This vacuum pulls open the valve opening of the filling valve (the inverted-cone-shaped valve element is kept closed by a spring), allowing oil from the upper tank to flow into the upper chamber of the master cylinder. Once the piston is in place, the spring closes the oil filling valve, and the press operates under the pressure supplied by the oil pump. Then the piston moves upward in reverse direction, and the oil pump supplies oil to the lower chamber of the main cylinder. Even before the piston starts moving, pressure builds up in the lower chamber; a small tube channels this pressure to the filling valve, causing it to open. As the piston rises, the oil in the upper chamber returns to the upper oil tank. Once the upper tank is full, a large pipe carries the excess oil back to the lower tank.

Thank you first, but I still haven’t understood it

Bro, did you write this nonsense on your own? It seems like a manual for an oil-powered engine? What the poster posted seems to be a corner valve, and it appears to come with a solenoid valve as well

It’s cold, seems to belong to the pilot valve!

Refrigerant flow control valve. Danvers

I just removed a similar valve a couple of days ago. What was said on the 6th floor is correct – it’s a pilot valve. Under normal conditions, the spool of the pilot valve is controlled by an electromagnetic valve, which keeps it in an open state. There is a spring inside the main valve, and under the pressure of the fluid acting on both the spring and the pilot valve, an equilibrium is maintained with the pressure of the fluid on the lower side of the main valve spool, thereby keeping the main valve spool closed. When the spool of the pilot valve closes under the action of the solenoid valve, the pressure of the medium on the upper side of the main valve is zero; the pressure on the lower side of the main valve is greater than the spring force, allowing the main valve to open normally

This post was last edited by 543323944 on 2017-6-16 at 16:03. It relates to Danfoss level control valves; I just managed to figure things out regarding them recently. Take a look at the post I’ve shared – it contains the instructions for the “level controller”. Danfoss Level Controller: http://bbs.hcbbs.cc/forum.php?mod=viewthread&tid=1788178 (Source: Haichuan Chemical Industry Forum). You can also go to Danfoss’s official website to find information on level controllers – they are available in the PMFL and PMFH types, and they are controlled by float level sensors (SV1/2/3/4/5/6). The instructions are included in the post I shared