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Valve industry terminology Strength performance The strength performance of the valve The ability of the valve to withstand the pressure of the medium. Valves are mechanical products that withstand internal pressure, so they must have sufficient strength and rigidity to ensure long-term use without rupture or deformation. Sealing performance The sealing performance of a valve refers to the ability of each sealing part of the valve to prevent medium leakage. It is the most important technical performance index of the valve. There are three sealing parts of the valve: The contact point between the two sealing surfaces of the opening and closing parts and the valve seat ； The matching of packing with valve stem and stuffing box ； The connection between the valve body and the valve cover. The first leakage is called internal leakage, which is commonly referred to as lax sealing. It will affect the valve's ability to cut off the medium. For cut-off valves, internal leakage is not allowed. The latter two leaks are called external leakage, that is, the medium leaks from inside the valve to outside the valve. Leakage will cause material loss, pollute the environment, and even cause accidents in severe cases. For flammable, explosive, toxic or radioactive media, leakage is not allowed, so the valve must have reliable * sealing performance. After the flowing medium flows through the valve, there will be a pressure loss (that is, the pressure difference before and after the valve), that is, the valve has a certain resistance to the flow of the medium, and the medium will consume a certain amount of energy to overcome the resistance of the valve. From the perspective of energy conservation, when designing and manufacturing valves, the resistance of the valve to the flowing medium should be reduced as much as possible. Hoisting and closing force and hoisting and closing torque Hoisting and closing force and hoisting and closing torque refer to the force or torque that must be exerted to open or close the valve. When closing the valve, it is necessary to form a certain sealing specific pressure between the two sealing surfaces of the opening and closing parts and the hair seat. At the same time, it is necessary to overcome the friction between the valve stem and the packing, between the valve stem and the thread of the nut, the valve stem end support and other friction parts. Therefore, a certain closing force and closing torque must be applied. During the opening and closing process of the valve, the required opening and closing force and opening and closing torque change, and their maximum value is at the final instant of closing or the first instant of opening. When designing and manufacturing valves, efforts should be made to reduce their closing force and closing torque. Opening and closing speed Opening and closing speed is expressed by the time required for the valve to complete an opening or closing action. Generally, there are no strict requirements for the opening and closing speed of valves, but some working conditions have special requirements for the opening and closing speed. Some require rapid opening or closing to prevent accidents, and some require slow closing to prevent water hammer. This should be considered when selecting the valve type. Movement sensitivity and * This refers to the sensitivity of the valve to respond accordingly to changes in media parameters. For valves such as throttle valves, pressure reducing valves, and regulating valves used to adjust medium parameters, as well as valves with specific functions such as safety valves and traps, their functional sensitivity and availability are * Performance is a very important technical performance indicator. Service life represents the durability of the valve, is an important performance indicator of the valve, and has great economic significance. It is usually expressed by the number of opening and closing times that can ensure the sealing requirements, or it can also be expressed by the use time. Type type Classification of valves according to purpose or main structural characteristics Model model Numbering of valves according to type, transmission mode, connection form, structural characteristics, valve seat sealing surface material and nominal pressure Connection dimensions Connection dimensions The main dimensions of the connection between the valve and the pipe General dimensions The opening and closing height of the valve, hand wheel diameter and connection size, etc. Connection form type of connection Various methods used to connect the valve to pipes or machinery and equipment (such as flange connection, threaded connection, welding connection, etc. seal test seal test Back seal test is a test to test the performance of the opening and closing parts and the valve body sealing pair. Back seal test is a test to test the sealing performance of the valve stem and valve cover sealing pair. seal test pressure. The pressure specified when the valve is performing a sealing test. Suitable medium. Suitable medium. Suitable temperature. Suitable temperature. The temperature range of the medium that the valve is suitable for. A general term for a part used to cut off or regulate the flow of media, such as the gate plate in a gate valve, the valve disc in a throttle valve, etc. Packing Packing is put into a stuffing box (or stuffing box) to prevent the medium from leaking from the valve stem. Packing seat is a part that supports the packing and keeps the packing sealed. Packing gland gland is a part bracket that is used to compress the packing to achieve a seal. yoke On the valve cover or valve body, the dimension of connecting channel used to support the valve stem nut and transmission mechanism. The structural dimensions of the opening and closing parts and the valve stem assembly connection. Flow area flow area refers to the minimum cross-sectional area between the valve inlet end and the valve seat sealing surface (but not the "curtain" area). It is used to calculate the theoretical displacement without any resistance. flow diameter flow characteristics corresponding to the diameter of the flow channel area. Under the steady flow state, when the inlet pressure and other parameters remain unchanged, the functional relationship between the outlet pressure and flow rate of the pressure reducing valve. Flow characteristics derivation. Under the steady flow state, when the inlet pressure and other parameters remain unchanged, the outlet pressure change value caused by the change of the pressure reducing valve flow rate. General valve. General valve. The valve commonly used in pipelines in various industrial enterprises. Automatic valve. Self-acting valve. * A valve driven valve that operates on its own due to the ability of the medium (liquid, air, steam, etc.) Actuated valve A valve operated by manual, electric, hydraulic or pneumatic pressure hammer blow handwheel A handwheel structure that uses impact force to reduce the operating force of the valve Worm gear transmission device wormgear actuator A device that uses a worm gear mechanism to open, close or adjust the valve Pneumatic actuator A drive device that uses air pressure to open, close or adjust the valve Hydraulic actuator The driving device that uses hydraulic pressure to open, close or adjust the valve. Hot condensate displacement. Hot condensate capacity. The trap can discharge condensate within 1/j command under a given pressure difference and temperature. ； Steam loss is the amount of fresh steam leaked from the trap per unit time.