How Danfoss solenoid valves work

　　The solenoid valve is an automatic basic element used to control the fluid and belongs to the actuator; Not limited to hydraulics and pneumatics. Solenoid valves are used to control the direction of hydraulic flow, and the machinery of the factory is generally controlled by hydraulic steel, so solenoid valves will be used.

The working principle of the solenoid valve, there is a closed cavity in the solenoid valve, there are through holes in different positions, each hole leads to a different oil pipe, the middle of the cavity is a valve, there are two electromagnets on both sides, which side of the magnetic coil energized valve body will be attracted to which side, by controlling the movement of the valve body to block or leak out different oil drain holes, and the oil inlet hole is normally open, the hydraulic oil will enter different oil discharge pipes, and then push the oil just piston through oil pressure, the piston drives the piston rod, and the piston rod drives the mechanical device. The mechanical movement is controlled by controlling the current of the electromagnet.

The above is the general principle of solenoid valves. In fact, depending on the temperature and pressure of the flowing medium, such as the pressure of the pipe and the self-flowing state, there is no pressure. Solenoid valves work differently.

For example, in the self-flowing state, zero voltage start-up is required, that is, after the power is applied, the entire coil will suck up the brake body.

In addition, the solenoid valve with pressure is sucked out of the pin inserted into the gate body after the coil is energized, and the gate body is lifted by the pressure of the fluid itself.

The difference between the two is that the solenoid valve in the self-flowing state is larger because the coil has to suck up the entire gate body.

Moreover, the solenoid valve with pressure only needs to suck up the pin, so the volume can be made relatively small.

Direct Acting Solenoid Valve:

Principle: When energized, the electromagnetic coil generates electromagnetic force, lifts the closing part from the valve seat, and the valve opens; When the power is off, the electromagnetic force disappears, the spring presses the shut-off against the valve seat, and the valve closes.

Characteristics: It can work normally under vacuum, negative pressure, zero pressure, but more than 25 mm.

Distributed direct-acting solenoid valve:

Principle: It is a principle that combines direct action and pilot. When there is no pressure difference between the inlet and outlet, after the power is applied, the electromagnetic force lifts the closing parts of the pilot valve and the main valve upwards in turn, and the valve opens. When the inlet and outlet reach the starting pressure difference, after the power is applied, the pressure in the lower chamber of the electromagnetic pilot valve and the main valve rises, and the pressure in the upper chamber decreases, so that the pressure difference is used to push the main valve open; When the power is off, the pilot valve uses spring force or medium pressure to push the shut-off part, move downward, and close the valve.

Characteristics: It can also operate under zero differential pressure or vacuum and high pressure, but the power is large and needs to be installed horizontally.

Pilot solenoid valve:

Principle: When energized, the electromagnetic force opens the pilot hole, the pressure of the upper chamber drops rapidly, forming a high pressure difference between the upper and lower parts around the closing parts, the fluid pressure makes the closing parts move upward, and when the valve is opened and the power is off, the spring force closes the pilot hole, and the inlet pressure quickly forms a high pressure difference around the closing parts through the bypass hole

Characteristics: The upper limit of the fluid pressure range is high, and it can be installed arbitrarily (needs to be customized), but it must meet the fluid pressure difference conditions.

How Danfoss solenoid valves work

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