Pneumatic valve test step at low temperature

low temperature test: pneumatic valve pneumatic valve installed in the test container, and all joints, ensure pneumatic valve packing in the container, the upper and the temperature in degrees.
in normal temperature and under the largest pneumatic valve test pressure, use nitrogen to do such as early detection test, to ensure that the pneumatic valve under the right conditions for test.
pneumatic valves in liquid nitrogen with the mixture of alcohol or liquid nitrogen temperature cooled to pneumatic valve in low temperature condition, the horizontal cover pneumatic valve body and valve cover.
under the working condition of low temperature temperature, operating in accordance with the following steps:
(1) under the working condition of low temperature temperature, soaking in all parts of the pneumatic valve until the temperature stability, ensure all pneumatic valve is measured with a thermocouple temperature uniformity;
(2) under the test temperature, repeat. 。 ( — The initial test;
(3) under the nominal pressure of test temperature and the pneumatic valve, pneumatic valve switch time do low temperature performance test, equipped with a driving gear pneumatic valves do actions according to the requirements of the test;
(4) in the largest pneumatic valve test pressure, according to the normal flow of pneumatic valve pneumatic valve seal test, for two-way sealed pneumatic valves shall be tested separately, leakage is measured with a flow meter, the leakage rate should comply with the table - Provisions;
5. Pneumatic valve is in open position, close the pneumatic valve outlet needle pneumatic valve, and pressure pneumatic valve body to seal test pressure, keep the min, check the packing place of pneumatic valves, pneumatic valve and pneumatic valve bonnet joint sealing;
6 pneumatic valve cover seal check, have a seal on the pneumatic valve should be tested for sealing test, test the pneumatic valve is fully open and closed on both ends, the pneumatic bubbled into helium in the valve to seal test pressure, loosen the packing gland, check the seal on the seal.
low temperature performance test results should comply with the table - The provisions of the.
the restoration of pneumatic valve to the environment temperature, repeat. 。 ( — Helium test test, measure and record pneumatic valve leakage, switching torque and with the results. 。 ( — Compare the readings.
after the test, in the clean and dust-free environment pneumatic valve, check the ease of disassembly and inspection of each parts wear and damage.
generation temperature test of pneumatic valve should be clean, dry, pneumatic valve is closed.
. 'low temperature pneumatic valve technical conditions' standard BS about cryogenic pneumatic valve test the content of the
low temperature pneumatic valve should not only satisfy the requirements of BS, but also comply with the provisions of the relevant product standards. BS standard scope is:
1) DN acuity mm, its maximum nominal size determined by the corresponding product standards;
(2) the temperature range is - C ~ - Degrees. Cryogenic pneumatic valve pneumatic valve, pneumatic valve cover adopt: LCB ( — ℃、LC( — ℃,CF ( ） ( — Low temperature air valve pneumatic valve stem: CrNi

news source pump pneumatic valve member: China zhejiang meters pneumatic valve co. , LTD. : reproduced please indicate.