Control valve place is used carry out implement nothing more than pneumatic, dynamoelectric, fluid is moved (electro-hydraulic move) these 3 kinds, its performance characteristics has actor of low quality each, cent narrates below.
1, pneumatic actuator: Labour controls nowadays great majority circumstance place is used carry out implement it is pneumatic actuator, because use gas source to become motive force, than below, than dynamoelectric move with fluid want economic material benefit, and the structure is simple, master easily and safeguard. By safeguard a viewpoint to look, pneumatic actuator is operated easily than the actuator of other type and school calm, also can realize the crossing-over that positive and negative controls very easily in the spot. Its biggest advantage is safe, when use positioner, to combustible explode easily the environment is ideal, and if telecommunications date is not of explosion proof or of intrinsic safety have the potential risk that causes fire because of strike a light. So, although range of application of dynamoelectric now control valve is wider and wider, but in chemical domain, pneumatic control valve still is holding absolutely dominant position.
The main drawback of pneumatic actuator is: Answer slower, control precision owes beautiful, fight deviate ability poorer, this is the condensability because of gas, when using big pneumatic actuator especially, air cram air cylinder and platoon sky need time. But this should be unchallenged, the control precision that because make,height does not beg in much operating mode and extremely fast answer and fight deviate ability.
2, dynamoelectric actuator: Dynamoelectric actuator basically applies at dynamical plant or nuclear power factory, because the course with a flowing, stable slow gentle needs in all of high-pressured water system. The main good point of dynamoelectric actuator is the constant thrust of high stability and user applicable, the biggest carry out implement the thrust of generation can be as high as 225000kgf, can achieve so big thrust only fluid is moved carry out implement, but fluid is moved carry out implement cost should be compared dynamoelectric a lot of taller. Dynamoelectric carry out implement fighting deviate ability is very good, the thrust of output or moment of force basically are constant, the OK and very good unbalance that overcomes medium, obtain the accurate control of pair of craft parameter, so control precision is carried out than pneumatic implement should tall. If deserve to use servo amplifier, can realize the crossing-over of action of positive and negative easily, OK also and relaxed set stops signal a powerful person condition (maintain / a standard-sized sheet / close completely) , and when breakdown, stay in certainly former, this is pneumatic is carried out implement be not made, pneumatic is carried out implement must have the aid of is protected at combining protection system one set to come true.
The defect of dynamoelectric actuator basically has: The structure is more complex, more incidental breakdown, and the complexity as a result of it, the technical demand that maintains staff to the spot wants relatively a few taller; Electric accident should produce heat all right, if adjust too frequent, cause electric machinery overheat easily, generation heats up protection, also meet those who increase pair of decelerate gear wear away at the same time; Move namely additionally slower, output a signal from adjuster, be answered to control valve and move that corresponding position, need longer time, this is it is moved as pneumatic, fluid carry out implement place.
Previous12 Next