Valve production is a more complex process, before the valve factory, through a series of pressure test, to ensure that each valve factory are in line with the standard. But do you know how the customer tests the valve after it arrives at the customer’s site, before the valve is installed and online? Today we will introduce 10 points about the principle of valve pressure test and points for attention.
1. Before the Valve on-line, the customer will check the valve spot check, the main test valve strength and tightness. For low-pressure valves, first draw 20 %, as long as found non-conforming products, should be 100% valve inspection. 100% inspection of medium and high pressure valves.
2.The liquid pressure test, the valve cavity air should be as empty as possible.
3. Stress should build up slowly and avoid sharp, sudden changes.
4. The duration of strength test and sealing type test is 2-3 min. Important and special valves should last 5 min. Small diameter valve test time can be correspondingly shorter, large diameter valve test time can be correspondingly longer. In the course of the test, if in doubt, the test time can be extended.
Do not allow sweat or leakage from body and cover during strength test. Sealing test, the General Valve only once, Safety Valve, high-pressure valve and another health valve to be carried out twice. Test, low-pressure, large-bore non-essential Valves and valves with provisions to allow leakage, allowing a small amount of leakage.
As the general purpose valves, power station valves, marine valves and other valves require different requirements, leakage requirements should be in accordance with the relevant provisions.
5. In the manual valve pressure test, the valve opening and closing is only allowed in the standard operating situation, not more than the specified number of valve opening and closing, to avoid the valve opening and closing torque reasonable misjudgment.
6. Where there is a drive device of the valve, test its sealing when the application of the drive to close the valve sealing test.
7. Cast Iron Valve Strength Test, the use of copper hammer tap valve body and cover, check whether there is leakage.
8. Valve test, in addition to the Plug Valve has provisions to allow the sealing surface of the oil, other valves do not allow the sealing surface of the oil test.
9. The valve pressure test, the valve blind pressure should not be too large, so as to avoid valve deformation. Cast Iron Valves may also be damaged if pressed too tightly.
10. The valve pressure test finished, should be timely drain the valve water and wipe clean, make a good test record.
Post time: Jul-28-2021