subject: Pneumatic-valve Maintenance Methods And Breakdown Reason [print this page] A, the focus of the maintenance check check body parts between wall: in high pressure differential and corrosive medium occasions, the body wall, diaphragm valve diaphragm is often affected by the impact of the media and corrosion, must check pressure on corrosion situation; To examine the seat: for work medium infiltration, fixed the seat of the inner surface with thread is vulnerable to corrosion and make the seat relaxation; Check valve core: valve core is one of the moving parts of the regulator, the medium erosion are serious, overhaul should seriously check valve core ministries are corrosion, wear, especially in high pressure difference, the wear and tear of the valve core because of cavitation causes of cavitation phenomenon is more serious. The serious damage valve core must be changed; Check the sealing filler: check whether overhauling asbestos rope dry, if use pan packing, should check whether ageing and its cooperate with face whether damage; Check the actuator rubber thin film whether ageing, whether to have cracked phenomenon.
Second, gas use regulator daily maintenance when regulator using graphite packing an asbestos, about three months in the packing should be added a lubricating oil, in order to ensure that the regulator flexible to use. Such as the discovery of packing gland cap pressure very low, it should be added packing, such as the discovery of pan b dry packing sclerosis, should be replaced immediately; Should be in the circuit check to attention in the running situation of the regulator, check valve position indicator and adjustment output fit with; For a locator regulator to always check gas source, find out problems timely treatment; Often should keep all the parts of the health and regulator complete works better.
Three, common fault and the reasons
(a) the regulator no action. Fault phenomenon and the reasons are as follows: 1. No signal, no air supply. (1) not open source, (2) the source of ice water because winter, cause congestion or duct, pressure reducing valve filter blocking failure, (3) compressor fault; (4) the air duct leakage. 2. Have gas source, no signal. (1) regulator fault, (2) the signal tube leakage; (3) the locator corrugated pipe leak; (4) the regulation of retinal damage. 3. Locator no air supply. (1) filter blocked; (2) the pressure reducing valve failure I (3) pipeline leakage or jam. 4. Locator have gas source, no output. Locator throttling hole plug. 5. A signal, no action. (1) the core fall off, (2) the core and social or and seat card to die; (3) stem to bend or break; (4) seat valve core frozen or coke piece of dirt; (5) actuators spring for a long time and rust.
(2) The action of the regulator is not stable. The phenomenon and cause of failure is as follows: 1. The air pressure is not stable. (1) compressor capacity is too small; (2) the pressure reducing valve failure. 2. The signal pressure is not stable. (1) control system of time constant (T = RC) not appropriate; (2) the adjustment output is not stable. 3. Air pressure is stable, the signal pressure is stable, but the action of the regulator is unstable. (1) in the ball valve locator amplifier by dirt wear off lax, gas consumption increase output concussion can produce the special; (2) the locator amplifier wards is not parallel flap, flap won't cover wards; (3) the output control, line leak; (4) actuators rigid is too small; (5) stem movement of friction resistance, and phase contact parts have the block phenomenon.
(3) regulator vibration. The phenomenon and cause of failure is as follows: 1. In all HeKaiDu regulator vibration. (1) Support instability; (2) near a vibration source; (3) the core and liner wear serious. 2. Regulator in close to full close position when the vibration. (1) The regulator chooses, often used in small open degree; (2) the flow direction of medium and single seat valve closed in opposite directions.
(4) The regulator slowed down. The dull phenomenon and the reasons are as follows: 1. Stem only in the single direction when slow movement. (1) pneumatic actuators diaphragm damaged in the thin film leak; (2) actuators in "O" type seal leakage. 2. Stem in reciprocating movement are slow phenomenon. (1) in the valve body sticking blocked; (2) the plan or graphite packing metamorphic sclerosis a asbestos packing oil dry; (3) packing add too tight, friction resistance increases; (4) due to stem not straight cause friction resistance; (5) no locator pneumatic-valve can also lead to action dull.
(5) The regulator leakage increased. The causes for the leakage of the following: 1. Valve leakage when seated. (1) the core is weak. Inside the severe leakage, (2) the good close valve not lax. 2. The valve cannot reach the fully closed position. (1) medium pressure difference is too big. Actuators rigid small, valve shut lax; (2) in the foreign body; (3) bushing sintering.
(6) flow adjustable decreases. The main reason is the valve core corrosion become smaller, so that the minimum adjustable flow get big. Understand the pneumatic-valve fault phenomena and reason, can suit the necessary measures.
