Excavator lifter several solenoid valves

Classification of solenoid valves.

Solenoid valves are divided into three categories in principle:

1. Direct acting solenoid valve: When energized, the solenoid coil generates electromagnetic force to lift the closing member from the valve seat, and the valve opens; when the power is off, the electromagnetic force disappears, the spring presses the closing member on the valve seat, and the valve closes.

2. Step-by-step direct-acting solenoid valve: It is a combination of direct-acting and pilot-operated type. When there is no pressure difference between the inlet and the outlet, after the power is turned on, the electromagnetic force directly pushes the pilot valve and the main valve closing part upwards in turn. Lift, the valve opens.

3. Pilot solenoid valve: When electrified, the electromagnetic force opens the pilot hole, the pressure of the upper chamber drops rapidly, and a pressure difference between upper and lower sides is formed around the closing element, and the fluid pressure pushes the closing element to move upward, and the valve opens;

When the power is off, the spring force closes the pilot hole, the inlet pressure through the bypass hole quickly forms a pressure difference around the valve closing member, and the fluid pressure pushes the closing member to move down to close the valve.