The following types of valves for boiler systems are: Main Steam Safety Valves, Electromagnetic Relief Valves PCV, Boiler Circulation Line Control Valves, Main Water Supply Bypass Regulating Valves, Reheater Spray Water Control Valves, Turbine High Pressure Steam Supply Regulators, Make a simple introduction.
1, the main steam safety valve
These types of valves have smaller reheat outlet calibers, about 150mm (6 inches), and pressures of 7 MPa. I now use the main steam engine in the three types of valve development projects to use the superheater outlet. Then it's The pressure will reach 27.6 megapascals. The flow rate of the main steam is larger than that of the reheater, which is nearly 3 times, so its caliber will also become larger. So these are the difficulties in developing such valves. This kind of valve requires us to make a fuss about the seals on springs, valve stems, valve discs and valve seats. The selection of spring materials is also very particular. For the tower boiler is a one hundred percent bypass, in the reheat outlet, also need to use safety valve, this type of safety valve is a brand of safety valve with pneumatic assist device similar to an electric release valve, such safety valve The calibre is also very large, about 300mm, and it may also be the direction we are about to study.
2, electromagnetic relief valve, that is, PVC valve
This kind of valve differs from the safety valve just described. It has a pressure switch to control the pressure, A switch, B switch or more switches to achieve a forced opening. This valve is relatively easy to run during operation, so it will often link below a shut-off valve. The type of shut-off valve may be a ball valve or a gate valve. Often the valve will have a pilot valve. The pilot valve later used auxiliary steam to push the opening of the integral valve.
3, boiler circulation line control valve
For ultra-supercritical boilers, the pipeline will be flushed after more than 150 hours of shutdown. In the process of flushing, firstly open flushing, then closed flushing, when the water in the outlet of the water separator is iron When the content is less than 100ug/L, we will perform cycle rinse. Because part of the water will always be discharged, in order to control the amount of water discharged and reduce the loss, we will increase the circulation valve control valve. This valve normally starts under 30%-25% load.
4, the main feed water bypass regulator
This kind of valve is similar to the type of circulation valve control valve just mentioned, so it will not be elaborated here.
5, reheater spray valve
Reheater spray control valve looks similar to the first two types of valves. First, such valves are not often used. Second, it has a lot of water, but it is used as an accident water spray.
6, steam turbine high pressure steam control valve
Steam turbine steam supply control valve should be a valve group, which is often caused by the gas seal of the turbine under high load conditions, no leakage inside and outside, three valves together, all the way from the high-pressure pump system, never leak in, It will not destroy its vacuum environment, does not leak out, can be connected to the auxiliary system, all the way from the low pressure bypass, its purpose is to reduce the loss of steam work.