What is a pilot-operated solenoid valve?
Direct-acting valve (direct-acting type) The working principle of a direct-acting valve is very simple. For this example, we will have a normally closed valve. Once the solenoid is de-energized, its spring will push the plunger, and then the plunger will close the valve port and rest against the seal. Once power is applied, the coil will pull the plunger upward and open the solenoid. For normally open valves, the situation is just the opposite. These solenoids are more used for small flows without high pressure. They can operate without any pressure or pressure difference, so they can be used even at zero line pressure.
Indirectly operated valve (pilot-operated type) Indirectly operated valves, sometimes also called pilot-operated valves, work according to the principle of pressure difference between the inlet and outlet. In this case, the valve port is closed by a diaphragm that separates the inlet and outlet openings. There is a hole in the diaphragm through which the medium can flow from the inlet 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 downward by a spring, and the pressure in the chamber above the diaphragm increases. Therefore, the diaphragm 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), which is closed by a piston. When the coil is energized, it lifts the piston upward, allowing the medium to flow through the pilot hole into the outlet. Because it is larger than the smaller hole, the pressure above the diaphragm is reduced, while the pressure in the inlet port remains unchanged and is now even higher. Therefore, it lifts the diaphragm and allows the medium to flow into the outlet. The pressure difference range is from 0.3 bar to 1 bar. For normally open valves, the working principle is just the opposite. These valves are suitable for larger flows.
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Shenyang HOlian Precision instrument co.,Ltd founded in 2017,is specialized production of oxygen generator accessories :Miniature solenoid valve for Portable Medical oxygen generator,4 Way 2 position Medical oxygen generator,3L to 10L Medical Oxygen Generator Solenoid Valve,pressure regulator assembly for oxygen concentrator,Pressure reducing Assembly for oxygen concentrator,Pinhole flowmeter of oxygen concentraror,Pinhole flowmeter of Medical oxygen concentrator,5L flowmeter for oxygen concentrator,Special firesafe Valve for oxygen concentrator,Firesafe Cannula Valve Oxygen Supply Tubing Connector,Oxygen primary filter,Medical Grade Filter,Check valve (material PA6),Check valve (material ABS),Oxygen generator accessories Molecular sieve tank head,Oxygen Concentrator Accessories Air Filters,Oxygen Concentrator Accessories NPT1/8-∅8 Connector,Oxygen Concentrator Accessories NPT1/8-∅10 Connector,Oxygen Concentrator Accessories 3 way Nozzle,Oxygen Concentrator Accessories 90° Nozzle,Mold manufacturing and i jection molding.