Sealing function and operating torque of groove butterfly valves
The advantage of groove butterfly valves is that the easier the valve is to close, the longer the service life of the PTFE sealing gasket with a wedge-shaped seat. The valve seat itself can also be replaced, so if the valve seat is damaged, there is no need to cut the valve body off the pipeline like other gate valves. The groove butterfly valve is connected for a long time without cutting or deformation during operation. When planning and manufacturing groove butterfly valves, efforts should be made to reduce their sealing force and torque. To deal with flammable, explosive, poor or sprayed media, external leakage is not allowed, and it is necessary for groove butterfly valves to have a sealing function.
The leakage at the back two points of the groove butterfly valve is called leakage, which means that the medium is leaked from inside the valve to outside the valve. When sealing groove butterfly valves, it is necessary to form a certain sealing pressure ratio between the opening and closing parts and the sealing surfaces of the seat. At the same time, it is also necessary to overcome the friction between the valve stem and the packing, between the threads of the valve stem and the nut, at the end support of the valve stem, and other friction parts. Therefore, it is necessary to apply a certain sealing force and sealing torque. The required opening and closing force and torque of groove butterfly valves during the opening and closing process are variable, and their maximum values are at the moment of sealing or opening. Opening and closing force and torque refer to the immersion force or torque required to open or close a groove butterfly valve. The previous disclosure in this is called internal leakage, which means that if the valve is not tightly closed, it will affect the ability of the groove butterfly valve to cut off the medium.
To prevent electrochemical corrosion, groove butterfly valves should avoid scratching the surface during transportation and installation of stainless steel and aluminum equipment and accessories. During construction, contact with other metals should be minimized as much as possible, and plastic cloth or other wrapping can be used when necessary. Soft pads should be added to the binding points of groove butterfly valve equipment and accessories to prevent equipment damage. Lifting should be carried out in sequence to prevent rework. When installing accessories, handle them gently and choose the correct lifting position for lifting heavy objects.
