进口调节阀的选型分析
进口调节阀的阀体类型选择调节阀的阀体种类很多，常用的阀体种类有直通单座（进口气动单座调节阀、进口电动单座调节阀）、直通双座（进口气动双座调节阀、进口电动双座调节阀）、角形（进口角型调节阀）、隔膜（进口气动隔膜调节阀）、小流量（进口小流量调节阀、进口小口径调节阀）、三通（进口三通合流调节阀、进口三通分流调节阀）、偏心旋转、蝶形（进口调节型蝶阀）、套筒式、球形（进口调节型球阀、进口V型切断球阀）等。在具体选择时，可做如下考虑：
(1) 阀芯形状结构主要根据所选择的流量特性和不平衡力等因素考虑。
(2) 耐磨损性当流体介质是含有高浓度磨损性颗粒的悬浮液时，阀的内部材料要坚硬。
(3) 耐腐蚀性由于介质具有腐蚀性，尽量选择结构简单阀门。
(4) 介质的温度、压力当介质的温度、压力高且变化大时，应选用阀芯和阀座的材料受温度、压力变化小的阀门。
(5) 防止闪蒸和空化闪蒸和空化只产生在液体介质。在实际生产过程中，闪蒸和空化会形成振动和噪声，缩短阀门的使用寿命，因此在选择阀门时应防止阀门产生闪蒸和空化。调节阀执行机构的选择为了使调节阀正常工作，配用的执行机构要能产生足够的输出力来保证高度密封和阀门的开启。对于双作用的气动、液动、电动执行机构，一般都没有复位弹簧。作用力的大小与它的运行方向无关，因此，选择执行机构的关键在于弄清最大的输出力和电机的转动力矩。对于单作用的气动执行机构，输出力与阀门的开度有关，调节阀上的出现的力也将影响运动特性，因此要求在整个调节阀的开度范围建立力平衡。执行机构类型的确定对执行机构输出力确定后，根据工艺使用环境要求，选择相应的执行机构。对于现场有防爆要求时，应选用气动执行机构。从节能方面考虑，应尽量选用电动执行机构。若调节精度高，可选择液动执行机构。如发电厂透明机的速度调节、炼油厂的催化装置反应器的温度调节控制等。调节阀的作用方式选择调节阀的作用方式只是在选用气动执行机构时才有，其作用方式通过执行机构正反作用和阀门的正反作用组合形成。组合形式有4种即正正(气关型)、正反(气开型)、反正(气开型)、反反(气关型)，通过这四种组合形成的调节阀作用方式有气开和气关两种。对于调节阀作用方式的选择，主要从三方面考虑a)工艺生产安全b)介质的特性c)保证产品质量，经济损失最小。
Control valve control valve valve valve type selection many different types of body types have commonly through single-seat, through two-seater, angular, diaphragm, low flow, tees, eccentric rotation, butterfly, sleeve type, ball and so on. In the specific choice, do the following considerations (1) spool shape and structure mainly based on the selected flow characteristics and unbalanced forces and other factors considered. (2) wear resistance when the fluid medium that contain high concentrations of wear particles in suspension, the valve's internal materials to be hard. (3) corrosion resistance as corrosive media, try to choose simple valve. (4), medium temperature and pressure when the medium temperature, high pressure and the variation shall be selected by the valve and seat materials, temperature, small changes in pressure valve. (5) to prevent steam and air steam and air produced only in a liquid medium. In the actual production process, steam and air to form the vibration and noise, shorten the life of the valve, so the choice should be to prevent the valves have valve steam and air. Valve actuator control valve to make the choice to work with the implementing agency to be able to use to generate sufficient output power to ensure a high degree of sealing and the valve open. For double-acting pneumatic, hydraulic, electric actuator, generally not reset spring. The size of the force and the direction it has nothing to do, therefore, lies in selecting executing agencies to ascertain the maximum output power and torque of the motor rotation. For single-acting pneumatic actuator, the output power and opening the valve, control valve on the emergence of the force will also affect the motion characteristics, thus requiring the entire range of valve opening to establish equilibrium. Determine the type of actuator output force of the implementing agencies to determine, based on the use of environmental technology requirements, select the appropriate enforcement agency. For the scene, explosion-proof requirements, should use pneumatic actuators. From energy considerations, should try to use electric actuators. If the adjustment of high precision, optional hydraulic actuators. Such as power plants and transparent machine speed regulation, refinery catalytic cracking unit reactor temperature adjustment control. Mode of action of control valve control valve selection in the selection of the mode of action is only when the pneumatic actuator, and its mode of action through the implementing agencies and the positive and negative effects of positive and negative role of the combination of valve formation. There are four combinations that are positive (gas-off), positive and negative (gas open type), anyway (gas open type), counter-countermeasure (gas-off), formed by a combination of these four modes of action with the gas control valve open gas off two. Mode of action for the choice of control valve, the main three aspects to consider a) process to produce safe b) characteristics of the medium c) to ensure product quality, minimize economic losses.
