A minute to understand what type of valve, how to classify! ! !

Valve is now in industrial production, the liquid flow rate on the pipe and control the common equipment, many different kinds of valves, the user chooses the valve how to classification, how to choose? First need to understand the basic performance and usage of each valve, a comprehensive introduction under the valve type, let you one minute to grasp knowledge and the selection of valve performance items: one, the valve can be divided into two categories: 1, drive valve: by manual, electric, hydraulic, pneumatic control valve action. Such as gate valve, cut-off valve, throttle valve, butterfly valve, ball valve, plug valves, etc. 2, automatic valves: rely on the media ( Liquid, gas) The ability of itself and action of the valve itself. Such as check valve, relief valve, regulating valve, drain valve, pressure reducing valve, etc. Second, according to the purposes, according to the different USES of the valve can be divided into: stop recycling: used to prevent the backflow medium, such as check valve. Regulate use: used to adjust the pressure and flow rate of medium, such as regulating valve, pressure reducing valve. In medium pressure relief valve: more than specified value, used to discharge redundant medium, to ensure the safety of pipeline systems and equipment, such as relief valve, valve accident. Distribution with: the flow direction of medium is used to change and distribution medium, such as the three-way cock, distributing valve, valve, etc. Open circuit use: used to put through or cut off the line media, such as the cut-off valve, gate valve, ball valve, butterfly valve, etc. Other special purposes, such as hydrophobic valve, exhaust valve, drain valve etc. Third, according to the pressure, according to the nominal pressure of the valve can be divided into: low pressure valve, nominal pressure PN≤ 1. 6 mpa valve ( Including PN≤ 1. 6 mpa steel valve) Medium pressure valve, nominal pressure PN2. 5 - 6. 4 mpa. High pressure valve, nominal pressure PN10. 0 - 80. 0 mpa. Ultrahigh pressure valve, nominal pressure PN≥ 100. 0 mpa. Vacuum valve: absolute pressure & lt; 0. 1 mpa high of 760 mm hg in the valve, usually expressed in mm hg or mm water column pressure. Four, press and pipeline connection points, according to the valve and pipeline connection mode can be divided into: flange connection valve: the valve body with a flange, flange connection of valve and pipeline in a. A grip on the clip connection valve: the valve body, valve connected to the pipe using clip. Card sets of connection valve: the card sets of valve and pipeline connection. Threaded connection valve: the valve body with internal thread or external thread, adopt threaded connection valves and pipes. Welding connection valve: the valve body with a joint, valves and pipeline welding connection. Five, according to the temperature of the medium, according to the valve working medium temperature can be divided into: normal valve: applicable to medium temperature - The valve of 40 ℃ ~ 425 ℃. Cryogenic valves: applicable to medium temperature - 150℃～ - The valve of 40 ℃. Cryogenic valves: applicable to medium temperature - The valve under 150 ℃. High temperature valves: applicable to medium temperature 425 ℃ ~ 600 ℃. Heat resistant valve: applicable to medium temperature above 600 ℃. Six, according to the nominal diameter points, according to the nominal diameter of the valve can be divided into: small diameter valves: DN< nominal diameter; 40 mm valve. Diameter of valve: valve nominal diameter (~ 300 mm. Nominal size of large diameter valves: DN350 ~ 1200 mm. Super-large diameter valves: DN&ge nominal diameter; 1400 mm of the valve. Seven, according to the structure characteristics, according to the close relative to the seat moving direction can be divided into: door form: closed a move along the seat center; Gate type: closed a move along the vertical seat center; Cock and ball: closing is a plunger or a ball, revolve around itself of the centerline; Swing type: closed revolve around the seat outside the shaft; Disc: close a disc, revolve around inside the seat axis; Slide valve type: shut down a slide in the perpendicular to the direction of the channel. Eight, according to the drive way, according to the different driving mode can be divided into: manual: the hand wheel, handle, lever or sprocket, human power, large torque fashion has a worm gear drive, gear reducer, etc. Electric: with the help of a motor or other electric device to drive. Hydraulic: with the help of ( Water, oil) To drive. Pneumatic: use compressed air to drive.