【文章內(nèi)容簡介】 d:1: with the aid of a handwheel, manual handle, lever or a chain wheel, a manpower driving, driving a larger torque, a worm wheel, gear deceleration device.2: with the aid of electric motor or other electrical device to drive.3: with the aid of fluid ( water, oil ) to drive.The 4 pneumatic。 using pressed air to drive.In four, according to the pressure, according to the nominal pressure of the valve can be divided:1: absolute pressure vacuum valve 760mm Hg higher valve, usually with mm Hg or mm column shows the pressure.2: the low pressure valve nominal pressure PN = valve (including PN less than or equal to steel valve )3 medium pressure valve: nominal pressure valve.4 high pressure valve: nominal pressure valve.5 super high pressure valve: the valve nominal pressure PN = .In five, according to the temperature of the medium is divided, according to the work of the medium temperature can be divided:1: the ordinary valve suitable for medium temperature 40 to 425 DEG C valve.2: high temperature valve suitable for medium temperature 425 to 600 DEG C valve.3: heat resistant valve for medium temperature above 600 DEG C for valve.4 cryogenic valves: applicable to the medium temperature of 40 DEG C to 150 degrees C. valve.5 cryogenic valve: applicable to the medium temperature of 150 DEG C below the valve.In six, according to the nominal diameter, depending on valve size can be divided:1: small bore valve nominal diameter DN 40mm valve.2 caliber valve: nominal diameter DN50 ~ 300mm valve.3: large diameter valve nominal diameter DN350 ~ 1200mm valve.4: large diameter valve nominal diameter DN = 1400mm valve.In seven, connected with the pipeline manner, according to the valves and pipelines connecting mode can be divided。The 1 flange connected valve body with flanges, and pipe: a flange connected valve.2: thread connection valve body with internal or external threads, and the pipe with threaded connection valve.3: welded valve body with welded joints, and pipe are connected by welding valve.The 4 clamp is connected to the valve : valve with mouth, and pipeline using a clamp connection valves.5 sets of cards: card sleeve and valve connected by pipeline connecting valve. The second chapter the valve installation, maintenance and operationThe correct choice of valve, but also the correct installation, maintenance and operation, so as to give full play to its performance. The first section of the installationValve installation quality, directly affects the use, so the need for careful attention.( a ) the direction and positionMany valves has direction, such as cutoff valve, throttle valve, relief valve, check valve, if installed flip reverse, it will affect the use effect and the life ( such as throttle ), or simply does not work ( such as valve ), and even dangerous ( such as a check valve ). General valve, the valve body has a direction sign。 if not, should according to the work principle, the correct recognition. The cutoff valve valve cavity leftright asymmetry, fluid to make its bottom up through the valve port, so that the fluid resistance is small (by the shape of the opening ), labor ( for medium pressure upward), after the closure of medium pressure filler, which is convenient for maintenance. This is why can not be an inverse stop valve. Other valves also have respective characteristics.The valve installed position, must facilitate the operation。 even if the installation of temporary difficulties, but also for the sake of longterm operating personnel work. The best valve handwheel and chest ( above the operating floor general even meters ), so, the valve is opened and closed more ease. Landing valve handwheel to move on, do not tilt, so as not to operate. Against the wall by the valve device, to allow the operator to stand. To avoid operation, especially acidbase, toxic medium, otherwise it is not safe to. Gate valves do not flip ( . handwheel ), otherwise it will make the medium long term retention valve cap space, easy corrosion valve, but also some technology requirements of the taboo. At the same time to replace the packing is not convenient.Rising stem gate valve, not installed in the ground, or corrosion due to moisture exposed stem.Lift check valve, when the valve installation to ensure its vertical, so that the flexible lifting.Swing check valve, installation to ensure its pin level, so as to swing and flexible.Pressure reducing valve to the upright installed in horizontal pipelines, all directions do not tilt.( two) construction workInstallation and construction must be careful to avoid collision, brittle material valve.Before the installation, should be a check valve, check the specifications, there is no damage identification, especially for the valve stem. Also a few turns, to see whether the skew, because the transport process, the most easily break valve. Will purge valve within the debris. Valve