Description of the sealing performance test of the vacuum baffle valve

The opening and closing force and the opening and closing torque refer to the force or moment that must be applied when the valve is opened or closed. When closing the valve, it is necessary to form a certain sealing pressure between the opening and closing parts and the sealing surface of the bearing seat, and at the same time overcome the between the valve stem and the packing, between the thread of the valve stem and the nut, and at the end of the valve stem and The friction of other friction parts must be applied with a certain closing force and closing torque. During the opening and closing process, the required opening and closing force and opening and closing torque are changed, and the large value is at the end of the closing or opening. The initial moment. When designing and manufacturing valves, it is important to reduce their closing force and closing torque.

The sealing performance of the valve refers to the ability of the sealing parts of the valve to prevent the leakage of the medium. It is an important technical performance index of the valve. There are three sealing parts of the valve: the contact between the sealing surface of the opening and closing parts and the valve seat; the joint of the packing with the valve stem and the stuffing box; the connection between the valve body and the valve cover. The leak in the former place is called endoleak, which is commonly referred to as the lack of tightness, which will affect the ability of the valve to cut off the medium. For shut-off valves, internal leakage is not allowed. The latter two leaks are called leaks, that is, the medium leaks from the valve to the outside of the valve. External leakage can cause material loss, pollute the environment, and cause accidents in severe cases. For flammable, explosive, toxic or radioactive media, external leakage is not allowed, so the valve must have a reliable sealing performance.