Pressure Reducing Valve

The pressure reducing valve is an important gas equipment in the supporting components of household gas appliances. It is installed on the angle valve of liquefied petroleum gas (LPG) cylinders to connect the angle valve and the hose, functioning to reduce and stabilize the output pressure. It boasts advantages such as a simple structure, stable pressure, light weight, and ease of adjustment and installation. It is mainly composed of components including an air inlet, an air outlet, a handwheel, an upper valve cover, a lower valve cover, an air inlet nozzle, a breathing hole, an upper air chamber, a decompression chamber, a valve pad, a lever, a rubber diaphragm, a spring, and an adjusting plug.

Working Principle of the Gas Pressure Reducing Valve

Its structural composition is shown in the right figure. As we know, when liquefied petroleum gas exits the cylinder, it is a high-pressure gas that first reaches the decompression chamber through the intake pipe. When the user turns off the switch of the gas appliance, as more liquefied petroleum gas enters the decompression chamber, its pressure rises, pushing up the rubber diaphragm pressed by the spring. At this point, part of the air in the upper air chamber is discharged from the valve body through the breathing hole. This forces the lever to move upward, and through the lever action, the valve port is closed, cutting off the inlet path of liquefied petroleum gas, so the pressure at the outlet of the pressure reducing valve no longer rises.

When the switch of the gas appliance is turned on, liquefied petroleum gas flows out of the pressure reducing valve, causing the pressure in the decompression chamber to drop. The rubber diaphragm then concaves downward, driving the lever to move down. External air enters the upper air chamber through the breathing hole, making the valve pad move toward the center, enlarging the air inlet nozzle, increasing the air intake, and thus raising the pressure. Through this continuous adjustment process, the pressure in the decompression chamber remains constant. That is, regardless of whether the inlet pressure is too high or too low, the outlet pressure remains stable, thereby achieving the functions of pressure reduction and pressure stabilization.