BURKERTBaldor solenoid valveThe way of operation is also different. They can be operated directly, where the coil opens the orifice directly, or they can be operated indirectly, i.e. they are controlled by the pressure difference between the inlet and outlet. The arrows on their bodies must point in the direction of flow in the pipe system.

Direct acting valve

The working principle of the direct-acting valve is very simple. For this example, we will have a normally closed valve. Once the solenoid is powered off, its spring pushes the plunger, which then closes the orifice of the valve and rests against the seal. Once powered on, the coil pulls up the plunger and opens the solenoid. For normally open valves, the opposite is true.

These solenoids are used more for small flows without high pressure. They do not require any pressure or differential pressure to operate, so they can be used even at zero line pressure.

Indirectly-operated valve

Indirectly operated valves, sometimes called pilot operated valves, operate according to the principle of differential pressure between the inlet and outlet. In this case, the valve port is closed by a diaphragm separating the inlet and outlet openings. There is a hole in the diaphragm through which the medium can flow from the entrance into the upper chamber. This balances the pressure acting on the diaphragm and keeps it closed.

Again, let's take a normally closed valve as an example. When the valve is not energized, the diaphragm is pushed down by the spring and the pressure in the chamber above the diaphragm increases. The diaphragm therefore closes the valve and the medium cannot flow. The chamber above the diaphragm is connected to the outlet opening through a small channel (pilot hole) that is closed by a piston. When the coil is energized, it lifts the piston up, allowing the medium to flow into the outlet through the pilot hole. Because it is larger than the smaller orifice, the pressure above the diaphragm is reduced, while the pressure in the inlet orifice remains the same and is now even higher. Thus, it lifts the diaphragm and allows the medium to flow into the outlet. Differential pressure ranges from 0.3 bar to 1 bar. For normally open valves, the working principle is exactly the opposite. These valves are suitable for larger flows.

What is the difference between direct acting solenoid valve and pilot operated solenoid valve? BURKERT solenoid valve problem. In addition, Shenzhen Oudejie Technology professional sales of new original imported BURKERT Baode solenoid valve, and promised to sell products are new original imported, while providing our customers with quotation, selection, product information and other services.