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Structural characteristics and industry standards of Bellows Valves
- Mar 21, 2018 -

Bellows valves undergo a series of rigorous inspection and test procedures, including 100% gas seal and no leak test. For the bellows with vacuum requirements, the vacuum gas tightness test can be performed with a helium mass spectrometer leak detector.

Bellows valve structure features:

1. The valve body and cover are connected with studs, simple structure and good process performance.

2. The stem of the valve not only has the stuffing box as the general valve, but also in the lower part of this stuffing box, there is a movable sealing element - stainless steel bellows in the upper part of the valve chamber, and the medium is enclosed in the valve chamber outside the valve stem. So the valve is more reliable than the general valve to prevent leakage, to ensure the seal of the valve stem and the valve cap.

3. The stem nut uses surface nitriding to increase the surface hardness and wear resistance and prevent bite phenomenon.

4. The flange bolts are made of high-strength alloy steel and have excellent high temperature creep resistance and are safe and reliable.

5. Bellows design in the valve cover cavity to avoid direct flushing with the media, improve the service life of the bellows.

6. The corrugated pipe is overlapped by 2~4 times to prevent the leakage of the valve due to the damage of the single layer of the corrugated pipe and prolong the service life of the valve.

7. Due to the long design of the bellows, the opening height is high, the main resistance of the fluid is reduced, and the flow resistance coefficient is small.

8. Double sealing with packing and bellows to achieve zero leakage.

Bellows valve design and manufacture is according to GB/T12224, DIN3202, DIN3239, ASMEB16.34, API602, MSS-SP-117.

Inspection and tests are according to API598, JB/T9092, DIN3230.