Name: ZMAX (ZMAQ) pneumatic three-way valve attributes: pneumatic control valve type selection: (1) determine the nominal pressure, not by Pmax to set PN, but to find the temperature, pressure, material from the table three conditions the corresponding values ??for the selected PN and meet the valve of the PN. (2) determine the valve type, the leakage meet process requirements. (3) determine the valve type, the working pressure should be less than the allowable differential pressure valve, such as not, it shall be considered or alternatively valve from a special perspective. (4) the temperature of the medium in the valve operating temperature range, the ambient temperature to meet the requirements. (5) consider the problem valve attempts to prevent the situation according to the medium is not clean. (6) According to the chemical properties of the medium resistance to corrosion considerations valve. (7) According to media pressure and containing a hard object, consider the problem of erosion and abrasion resistant valves. (8) the performance of the overall economic effect is considered, the price ratio. . Need to consider three questions: a simple structure (as simple as higher reliability), easy maintenance, spare parts have sources; b.T969H electric high-pressure regulating valve life; c prices. (9) a preferred order. Butterfly - single-seat valve - seat valve - sleeve valve - angle valve - three way valve - ball - eccentric rotary valve - diaphragm. Select the implementing agencies: (1) The simplest is the pneumatic diaphragm type, followed by the piston, and finally the electric. The main advantage of (2) electric actuators are the driving source (power supply) is convenient, but the price is high, reliability, water proof as pneumatic actuators, pneumatic therefore should be preferred. (3) the old bulky electric actuators, we have electronic precision small high reliability of electric actuators provide (their prices high). (4) the old ZMA, ZMB diaphragm actuator can be eliminated (to improve performance, weight, height decreased by about 30%) by more than a light spring actuators instead. Recommendation (5) T969H electric high-pressure regulating valve piston actuator specification more varieties, old, big and stupid is no longer optional, and use light new structure. Choice of materials: (1) Body pressure rating, temperature and corrosion resistance, etc. should not be less than the required process connection pipes and styling products should be preferred manufacturer. (2) more water vapor or moisture content of wet gas and explosive media, should not use cast iron valves. (3) when the ambient temperature is below -20 ℃ (especially in the north), should not use cast iron valves. (4) on cavitation, erosion Cartesian coordinate more serious form of medium temperature and pressure, and the temperature of 300 ℃, pressure 1.5MPa two connections for the region outside of the sealing surface should be used for throttling wear-resistant materials, such as cobalt-based alloy or surfacing Division Terai alloy. (5) for corrosive media, the choice of corrosion resistant alloy must be based on the type of media concentration, temperature, pressure difference, choose a suitable corrosion-resistant material. (6) pieces were treated with the throttle body, throttle body wall to allow a certain speed small and corrosion, the corrosion rate can be around lmm / year; cutting pieces by high-speed erosion, corrosion will bow [from leaks by large, the corrosion rate should be less than 0.1mm / year. (7) The temperature of the lining material (rubber, plastic) of the selection of the working medium, the pressure must be used to meet the range of the concentration of the material, its physical and mechanical damage (such as a shear failure) while taking into account the operation of the valve . (8) should not use vacuum valve body lined with rubber, plastic structure. Two (9) water treatment system shut-off valve should not use rubber lining material. Typical corrosion resistant alloy material selection (10) Typical media: a acid:. 316L, Hastelloy, Alloy 20. b nitrate: aluminum, C4 steel, C6 steel. c *:. Harrington B. d hydrofluoric acid: Monel. e acetic acid, formic acid:. 316L, Hastelloy. f phosphate: Seoul due to nickel, Hastelloy. g urea:. 316L. h caustic soda: Monel. . i chlorine: Hastelloy C. j sea: because they can nickel Seoul, 316L. (11) By far the most versatile corrosion-resistant material is PTFE, known as the "King of corrosion." Therefore, you should first choose tetrafluoroethylene corrosion valve, the last resort (such as temperature> 180 ℃, PN> 1.6) was selected alloys. T969H electric high-pressure regulating valve flow characteristic selection: provided below are preliminary selection, detailed selection of specialized information, see: (1) S> 0.6 when the election of a few features.