Pressure reducing valve functions and maintenance

A pressurereducing valve regulates system pressure. To effectively do this, it must change the amount of pressure reduction and this depends on the incoming flows pressure. As the pressure of the fluid entering the pressure reducing valve increases, the main body valve will close causing a greater reduction in the pressure of the fluid flowing out. Similarly, as the pressure of the fluid flowing in reduces, the main body valve will open and this will cause a lesser reduction in the out-flow pressure. This device thus reduces pressure according to the conditions of the discharge flow so as to maintain a constant system pressure. The system itself is designed in that the discharge pressure from the pump will always exceed the desired system pressure. Thus, this device will then reduce the overage pressure to the desired constant system pressure. The performance of the pressure reducing valve will see variations in how the pump operates and also variations in the system supply pressure.

A reducing valve has two main sections or parts that enable it to function properly. One is the main body valve assembly and the other one the pilot assembly. As the name suggests, the main body assembly is the part of the valve in which the main flow travels. Due to its enormous functions, it is further divided into several sub-assemblies which include the valve cover, cover spring, main body diaphragm, valve stem, main body seat and the strainer. For the pilot assembly, it s work is to control the opening and closing of the main assembly. Thus its function is supportive but without it the main body valve can never function. As the incoming pressure of the fluid increases, so will the pressure in the pilot circuit. This pressure is thus transported to the top of the diaphragm causing the pilot assembly to close, which will automatically lead to the closing of the main assembly valve. The reverse is true; a reduction in pressure will lead to opening of the pilot valve thus leading to the opening of the main assembly.

Some of the common problems that one might face when operating a pressure reducing valve will include, having air in the pilot assembly. Ensure that you blend out any signs of building up gases in the pilot assembly since lack of it can lead to complications. Another problem is having a clogged strainer. Debris in the strainer can cause the valve to stop opening and closing as scheduled, thus close the isolation ball valves and remove the strainer and thoroughly clean it off any debris.

Similarly you might face a problem of diagram failure. This might be due to wear and tear which causes the diaphragm to wear out. This will lead to complications like the pressure reducing valve inability to close, upsets of the pressure balance which makes it to constantly fly out and so forth. The pilot diaphragm damage is characterized by water leakage. To solve these problems, replace the damaged diaphragm which can be easily done by removing the diaphragm cover, pull away the diaphragm washer plate and replace the diagram.