The safety valve of the subdivision and difference is introduced

Safety valve is a safety valve, a closed system under the action of the open-close part affected by external forces in a normally closed state, when the closed system of medium pressure increases, more than e. automatically when the safety valve open, through a discharge medium system to reduce the system pressure to prevent the destruction of the medium to high pressure in the system. Safety valve belong to automatic valve class, mainly for the boiler, pressure vessel and air conditioners, solar line, control pressure shall not exceed the specified value, to protect personal safety and equipment operation plays an important role. The safety valve of the terms: ( 1) Safety valve. A kind of automatic valve door. It without any external force, but use soil to discharge a nominal amount of fluid medium itself in order to prevent the system pressure exceeds a predetermined TVC within; After the pressure back to normal, the valve door shut down and prevent any media continue to flow out. ( 2) Direct load type safety valve. By a direct action of mechanical load, such as leveraged aggravating hammer or a heavy hammer, to overcome the valve disc spring under medium pressure generated by the reaction of safety valve. ( 3) Motivating the safety valve of auxiliary device. The safety valve using a power aided device, can be in below the normal open under pressure to open. Even if the assist device malfunction, such safety valve can still meet the standard requirements. ( 4) Safety valve with added load. This safety valve in the inlet pressure to always keep one before opening pressure increase the pressure seal. The additional force ( Supplementary load) Can be provided by the external energy, and when the pressure of safety valve to open should be released in a reliable way. Its size should be set so that assumes that the additional force is not released, safety valve can still opening pressure at the inlet pressure shall not exceed the national rules and regulations premise to achieve the rated capacity percentage. ( 5) Pilot operated safety valves. From a rely on guide valve discharge medium to drive or control of the safety valve. The guide valve itself should be meet the requirements of the standard load safety valve directly. ( 6) The proportion of type safety valve. In the opening range, or in a considerable proportion of the opening range safety valve opened or closed. ( 7) All rev type safety valve. A kind of open only within the scope of the small opening ratio, then suddenly open safety valve to full open position. Open height not less than 1/4 runner diameter. ( 8) Micro type safety valve. Is an only direct acting safety valve for liquid medium. Opening in 1/40 ~ 1/20 port diameter range. ( 9) Opening pressure ( The rated pressure) 。 Safety valve flap valve under the condition of the running start rising when the inlet pressure, under the pressure, began to have a measurable open height, medium is conditions for continuous emissions by the power of sight or hearing. ( 10) Discharge pressure. The valve disc to open height when the inlet pressure. The cap on the discharge pressure to conform to the demands of the relevant national standards or specifications. ( 11) More than pressure. Discharge pressure and opening pressure difference, usually expressed in the percentage of opening pressure. ( 12) Back pressure. After the discharge valve disc to contact with the valve seat, the opening into the inlet pressure to the zero. ( 13) Differential pressure opening and closing. Opening pressure and back pressure difference, usually expressed in back pressure and the percentage of opening pressure, only when the opening pressure is very low with the pressure difference. ( 14) Back pressure. The safety valve outlet pressure. ( 15) The rated discharge pressure. The upper limit of standard discharge pressure. ( 16) Seal test pressure. The inlet pressure to the sealing experiment was carried out, under the pressure measured by closing a sealing surface leakage rate. ( 17) The opening height. The valve disc to leave the actual lift in the closed position. ( 18) Port area. Refers to the inlet valve disc is to shut down a sealing surface flow between the minimum cross-sectional area, used to calculate without the theoretical displacement of impact resistance. ( 19) The runner diameter. Corresponding to the diameter of the port area. ( 20) Curtain area. When the valve disc in the valve seat above, in the form of formed between the sealing surface of a cylinder or cone surface shape channel area. ( 21) Discharge area. Valve gate discharge fluid channel, the minimum cross-sectional area. For all revelation safety valve, the discharge area is equal to the port area; For tiny qi type safety valve, discharge area is equal to the shade area. ( 22) The theory of displacement. Flow and safety valve port area section of the ideal of equal nozzle displacement calculation. ( 23) Discharge coefficient. The ratio of actual displacement and displacement theory. ( 24) The rated discharge coefficient. The discharge coefficient and reduction coefficient ( Take a 0. 9) The product. ( 25) The rated capacity. Refers to the actual displacement is allowed in the as a safety valve that part of the applicable benchmark. ( 26) Equivalent displacement calculation. Refers to the condition such as pressure, temperature, dielectric properties and the application of the rated discharge conditions at the same time, the calculation of safety valve capacity. ( 27) Jumping frequency. Safety valve valve disc unusually rapid movement back and forth, in the movement of the valve flap valve seat contact. ( 28) Flutter. Safety valve valve disc unusually rapid movement back and forth, do not contact with the valve seat valve disc in the movement. http://www。 nwfamen。 com/news/T1/110。 html