Pneumatic control valve pressure test preliminary < / div >

with the progress and development of modern industry, the growing demand for pneumatic valve, a modern petrochemical enterprises requires tens of thousands of pneumatic valve. Today, gradually become the mainstream of automatic control, manual operation were replaced by a mechanical or automation equipment. Risk in some occasions, the automation of the actuator device can reduce the damage, so pneumatic valve pneumatic control became a petrochemical enterprise is one of the most widely used instrument. But their problems in daily production is relatively more, so must be strictly before installation of pressure test, to ensure that in the actual production in normal work, and ensure the normal operation of the devices and safety production.
the so-called pneumatic regulating pneumatic valve is to point to by all kinds of pneumatic actuators and pneumatic valve pneumatic pneumatic valve adjustment. It was based on the compressed air as power source, the cylinder as actuator, and with the aid of electric pneumatic valve positioner, converters, solenoid pneumatic valve, pneumatic valve for attachment to drive the pneumatic valve, realize the switch quantity or proportion type adjustment, industrial automation control system receives the control signal to complete conditioning pipeline medium: flow, pressure, temperature and other process parameters. Because of its structure characteristics, so at the time of pressure test are part of pneumatic valve for pressure test, as well as pressure test was carried out on the actuator part.
after a lot of pressure test was carried out on the pneumatic valve pneumatic control as well as the test record data statistics and analysis, found that nearly 50% of regulating pneumatic valve has certain quality problems. Problems are mainly concentrated in excessive leakage and out-of-tolerance, pneumatic valve strength unqualified these three aspects. This means that want special attention to these aspects in the process of test. To adjust the pressure test of pneumatic valve mainly includes air tightness test, the actuator pressure strength test, pneumatic valve shell strength test and sealing test.
for pneumatic actuator part, should carry on the compression strength test. Tests to be carried out under the conditions of pneumatic valve fully open, choose clean water medium, test pressure shall be the nominal pressure of 1. 5 times, in all the work pressure of the pneumatic valve cavity under pressure of time should not be less than 3 min, there should be no leakage during.
for the chamber part of the actuator, should carry on the air tightness test, actuator chamber shall ensure air tight. Should be in the rated pressure of 0. Under 1 mpa air, the clean gas ( Air or nitrogen) Input membrane air chamber, within 5 min after cut off the gas source, gas chamber pressure should not drop.
for pneumatic valve parts, must carry on the compression strength test, packing and other joint leakage test. Experiment medium for room temperature water, the water can contain rust preventive oil or water soluble, must pay attention to according to the regulation of pneumatic valve inlet direction input regulating pneumatic valve pneumatic valve body, the other end closed, all in the work pressure of the pneumatic valve cavity at the same time bear the test pressure of not less than 3 min, there should be no leakage. Adjust the volume of the pneumatic valve leaking
experiment chooses clean water as a medium, test pressure of 0. 35 mpa, if without the permission of the pneumatic valve differential pressure is less than 0. 35 mpa should be specified value for design file. Open test, gas regulating pneumatic valve pneumatic pressure signal should be zero; Gas regulating pneumatic valve closed type signal pressure appropriate add 20 kpa for the upper limit of the input signal; Cut type pneumatic valve adjustment of signal pressure shall be the design documents specified value. When the test pressure for the maximum working pressure difference of pneumatic valve, pressure signal of the actuator shall be the design documents specified value.
in the determination of deviation, adjust the trip rating of the pneumatic valve to add input signal to pneumatic actuators chamber ( Or locator) Go all the way, make the pneumatic valve rod.
before using pneumatic regulating pneumatic valve, pressure test is very necessary to a work. Through the air tightness test, the actuator pressure strength test, pneumatic valve shell strength test and sealing test, not only can regulate the performance of the pneumatic valve and confirm the quality, but also for the future in the actual production process can be normal work, play a role, to ensure the normal operation of enterprises laid a solid foundation.