High pressure safety valve
High pressure safety valve is a safety valve, the opening and closing pieces under the action of external force in a normally closed state, when the equipment or piping within the medium pressure increases, more than a specified value automatically when open, through a discharge medium system to prevent the pipeline or equipment within the medium pressure in excess of the prescribed value. Safety valve belong to automatic valve class, mainly for the boiler, pressure vessel and piping, control pressure shall not exceed the specified value, to protect personal safety and equipment operation plays an important role. According to the safety valve open valve disc height can be divided into a safety valve and micro all rev type safety valve, micro rev type safety valve opening stroke height is: & le; 0. 05d0( Minimum discharge throat diameter) ; All rev type safety valve opening height is & le; 0. 25d0( Minimum discharge throat diameter) 。 High pressure safety valve, the form of the structure is divided into vertical hammer, lever, spring type and leading type ( Impulse type) ; According to the valve body structure, can be divided into two kinds of, closed and not closed. Enclosed type safety valve that is ruled out medium is not leaked out, and all along the discharge to the designated location, commonly used in toxic and corrosive medium. For air and steam safety valve, use no more enclosed safety valve. For the selection of safety valve products, should according to the actual seal pressure to determine. For spring loaded safety valves, in a nominal pressure ( PN) Has several work stress level within the range of the spring, when placing order, in addition to indicate safety valve model, name, medium and temperature, still should indicate the valve body sealing pressure, or else the maximum sealing pressure supply. High pressure of safety valve installation and maintenance should be paid attention to the following items: all kinds of safety valve should be installed vertically. High pressure safety valve outlet should be without resistance, avoid to produce compression phenomenon. Safety valve before installation should be specially test and check its official seal. The use of the safety valve should be checked regularly. Safety valve installation shall meet the following requirements: ( l） Rated capacity greater than zero. 5 t/h boiler, installed at least two safety valves: rated evaporation is less than or equal to zero. 5 t/h boiler, at least with a safety valve. Can be divided into type economizer exit, the steam superheater safety valves must be installed at the exit. ( 2) High pressure safety valve should be installed vertically in the pot, the top of the header. Between the safety valve and the drum or header, shall not be equipped with access steam outlet pipe and valve gate. ( 3) Lever type safety valve to prevent heavy hammer to mobile devices and on its own limitation lever deviant guide frame, spring loaded safety valves must be improve and prevent in hand twisted casually adjusting screw of the device. ( 4) For the rated steam pressure is less than or equal to 3. 82 mpa boiler safety valve throat diameter should not less than 25 mm: rated steam pressure is greater than 3. 82 mpa boiler safety valve throat diameter should not less than 20 mm. ( 5) High pressure boiler safety valve and connecting pipe, the cross-sectional area shall be not less than the safety valve of the cross-sectional area of imports. If several safety valve installed on a common attached directly to the drum of the short tube, the access of the short tube cross-sectional area should not step in all the safety valve exhaust steam area 1. 25 times. ( 6) General safety valve should be installed exhaust steam pipe, steam pipe should be road safety, and have enough area, ensure the exhaust steam flow. Safety valve at the bottom of the exhaust pipe should be put on AIRS have received safety drain pipe, on the exhaust pipe and drain pipe, are not allowed to furnish the valve gate.