The actual application of pneumatic diaphragm regulating pneumatic valve in fault analysis

Pneumatic diaphragm regulating pneumatic valve, pneumatic valve pneumatic for short adjustment by the adjusting of pneumatic valve and pneumatic diaphragm actuator. Pneumatic diaphragm regulating pneumatic valve by its simple structure, low failure rate and affordable and more and more applied to various occasions. But in the long time use, also can appear some fault, which requires us to solve in time, the enterprise losses to a minimum.










pneumatic diaphragm regulating pneumatic valve




pneumatic diaphragm regulating pneumatic valve in the practical application of fault are: plugging

1 card card plugging in pneumatic diaphragm regulating pneumatic valve is often appear problem, often occur in the new operation system and after overhaul of commissioning period. This is because the pipeline internal welding slag, iron and other impurities in the throttle opening and guide parts together to produce blocking phenomenon. After card wall, can make the medium flow or adjust the pneumatic valve packing too tight in the maintenance, the friction is bigger, produce small signal action, the phenomenon of large signal action too.


2 not doing regulating pneumatic valve action not fault phenomena including:
( 1) No signal, no air. Reason is air did not open or air supply fails, the duct blockage or reduced pressure pneumatic valve failure, due to the congestion happen compressor trouble light;
( 2) Air supply, no signal. Reason is the locator as bellows burst leakage phenomenon and fails, or converter failure;
( 3) The locator without air. Cause is the clogging filter, pressure reducer phenomena and failure;
( 4) The locator is air but not output. Reason is the locator orifice with clogs and failure;
( 5) Have a signal, no action. Reason is a pneumatic valve core loss; Pneumatic valve rod bent or broken.









pneumatic two-seater regulating pneumatic valve





3 oscillations regulating pneumatic valve oscillation due to the reason is the insufficient regulating pneumatic valve spring stiffness, regulating pneumatic valve output signal is not stable and the sharp change, adjust the frequency and the frequency of the system of the pneumatic valve, pipes and same base violent vibration. And adjust the improper pneumatic valve type selection, work in regulating pneumatic valve small open degree, a dramatic change of flow resistance, flow velocity and pressure, when the change over regulating pneumatic valve stiffness, lower the regulating the stability of the pneumatic valve, severe cases will produce pneumatic valve oscillation adjustment.


4 leakage pneumatic diaphragm regulating pneumatic valve leakage generally includes pneumatic valve leakage, packing leakage, pneumatic valve core and pneumatic seat deformation caused by the leakage.
( 1) Pneumatic valve leakage, is due to the length of the pneumatic valve stem is not appropriate, gas drive pneumatic valve pneumatic valve rod through the long, make the distance of the pneumatic valve lever upwards or downwards too short, lead to the pneumatic valve core and pneumatic seat that there was a gap between the not fully contact, resulting in a pneumatic valve leakage phenomenon.
( 2) Packing leakage, packing, wrapped to the stuffing box, will adjust the axial pressure pneumatic valve. Due to packing plastic deformation occurs, will produce radial pressure, close contact with pneumatic valve stem, but uneven contact. Regulating pneumatic valve in the process of work, pneumatic axial movement happens between stem and packing. Under the environment of high temperature and high pressure, under the influence of the high permeability media, prone to packing leakage.
( 3) Pneumatic valve core and pneumatic seat leakage deformation, mainly because of regulating pneumatic valve in the process of production, in the process of casting or forging strong corrosion and corrosion medium through the fluid medium. Corrosion mainly erosion and corrosion. Regulation through high corrosive medium pneumatic valve, the erosion of the pneumatic valve core and pneumatic seat and impact, and make it happen deformation, with the passage of time, will produce pneumatic valve core and pneumatic seat does not match the phenomenon, there is gap between them, and lax and leakage.

5 slowed

in the operation of the pneumatic membrane in damage leakage, pneumatic valve stem in a single direction moves slow; Locator reaction performance is weaker, leads to the adjusting pneumatic valve slowed; Adjust the pneumatic valve with rust on obstruction, the clogging phenomena, to adjust the pneumatic valve slow in axial movement; Poor quality of packing, or packing filling is too tight. Make friction resistance increases, leading to adjust the phenomenon of pneumatic valve action is slow.






6 action unstable
regulating pneumatic valve action unstable reason:
( 1) Compressor capacity is too small, resulting in reduced pressure pneumatic valve fails, the air pressure is causing unstable phenomenon;
( 2) Regulator is not stable, the time constant of the control system is not appropriate, resulting in a pressure signal unstable phenomenon;
( 3) Pneumatic valve rod in the movement of the friction resistance is very big, will happen in the process of contact block phenomenon;
( 4) Amplifier of the pneumatic valve positioner down the dirt and wear closed lax, special gas consumption increase would produce output volatility; Locator nozzle baffle amplifier of parallel, shutter nozzle.


this is pneumatic diaphragm regulating pneumatic valve in the practical application of fault analysis, welcome to add!