The valve is an important component of petroleum and chemical plants, and the successful operation of any device is inseparable from the correct selection of valves. Therefore, the valve selection is neither just considering the characteristics of the valve itself, nor just the professional design of pipes.

The valve industry is truly broad and diverse; valves are found in our homes, our offices, under our streets and in all our factories and plants.

Introduction—Seals in an Industrial ValveValve seals are a critical component in the overall development of a new valve. In addition, upgrading seals in an existing device with the properly selected retrofit has the potential to enhance valve life and performance while reducing leakage and mean time

After the valve is used for a long period of time, the sealing surfaces of the valve disc and the valve seat will wear out and the tightness will be reduced. Repair sealing surface is a large and important work. The main method of repair is grinding.

Several companies have evaluated current industry standards and have crafted testing protocols specific to their application requirements. However, as the industry moves forward, end users and valve manufacturers should consider using a standard that best fits their needs.

The screw threads of NRS gate valve lift the gate are exposed to fluid being controlled by the valve. This can cause problems if the fluids tend to foul the threads. So the non risint stem gate valve are usually on the clean liquid or gases.Rising stem gate valve have the threads external to the valve.