What kind of solenoid valve is used to make the cylinder have three positions? How to control it?

Theoretically, the three-position five-way intermediate sealing solenoid valve can be used as an intermediate stop loop, but in fact, due to the high compressibility of gas, this intermediate stop has no accuracy, because it is normal to inertia for several centimeters.

When electrified, the electromagnetic force opens the pilot hole, and the pressure in the upper cavity drops rapidly, forming a pressure difference between the upper and lower parts around the closing part, and the fluid pressure pushes the closing part to move upwards, so that the valve is opened; When power is cut off, the pilot hole is closed under the action of spring force, the inlet pressure quickly forms a low-high pressure difference around the closing valve through the bypass hole, and the fluid pressure pushes the closing piece to move downwards to close the valve.

Extended data:

Principle: When electrifying, the electromagnetic coil generates electromagnetic force to lift the closing piece from the valve seat and open the valve; When the power is cut off, the electromagnetic force disappears, the spring presses the closing piece on the valve seat, and the valve closes. Features: It can work normally under vacuum, negative pressure and zero pressure, but its diameter is generally less than 25mm.

Stepping direct-acting solenoid valve

Principle: It is a combination of direct-acting and pilot-acting. When there is no pressure difference between the inlet and outlet, the electromagnetic force directly lifts the pilot small valve and the main valve closing piece in turn, and the valve opens.

When the inlet and outlet reach the starting pressure difference, the electromagnetic force guides the small valve, and the lower chamber pressure of the main valve increases and the upper chamber pressure decreases, so that the main valve is pushed upward by the pressure difference; When power is cut off, the pilot valve uses spring force or medium pressure to push the closing piece to move down and close the valve.

Baidu encyclopedia-electromagnetism valve