What is the classification and working principle of solenoid valve in cold drawing three-way machine?
A, direct acting solenoid valve
Principle: when energized, the electromagnetic coil produces electromagnetic force to lift the closing parts from the seat, the valve opens; Power, the electromagnetic force disappears, the spring to close the pressure on the seat, the valve closed.
Features: in vacuum, negative pressure, zero pressure can work normally, but the diameter is generally not more than 25mm.
Two, distributed direct acting solenoid valve:
Principle: it is a direct and pilot combined principle, when there is no pressure difference between the entrance and exit, energized, electromagnetic force directly to the pilot valve and the main valve closing parts in turn up, the valve opened. When the inlet and outlet to start the differential pressure, energized, electromagnetic force pilot valve, the main valve chamber pressure rise, the upper chamber pressure drop, so as to use the differential pressure to push the main valve upward; When power is off, the pilot valve uses spring force or medium pressure to push the closing parts, moving down to close the valve.
Features: in zero pressure difference or vacuum, high pressure can also be reliable operation, but the power of the solenoid valve principle
Three, pilot solenoid valve:
Principle: when energized, the electromagnetic force to open the pilot hole, the chamber pressure drops rapidly, the formation of low and high pressure difference around the closed parts, fluid pressure to push the closed parts to move up, the valve opens; When the power is off, the spring force to close the pilot hole, the inlet pressure through the bypass hole rapidly chamber in the closed valve parts around the formation of low high pressure difference, fluid pressure to push the closing parts to move down, close the valve.
Features: high upper limit of fluid pressure range, can be arbitrarily installed but must meet the condition of fluid pressure difference
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