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If the medium remained in the cavity after the cryogenic gate valve is closed, the residue will gradually absorb the heat in the air and re-gasify. After the gasification, it will expand violently up to 600 times and generate extremely high pressure on the valve, which is called 'abnormal boost'. When the unusual occurrence happens, the wedge will be pressed firmly onto the seat and can’t be opene...
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6.For globe valve and choke valve When it comes to the strength test of the globe valve and the choke valve, the assembled valve is usually placed in the pressure test frame. Then, open the wedge, inject the medium to the specified value, finally check if the body and the bonnet of the valve‘sweat’or leak. Only the globe valve can be put in the sealing performance test. During the test, keep the s...
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3, For Butterfly Valve The pneumatic test of the butterfly valve is the same as the test of the globe valve. The test medium should flow into the valve from the inputting end when the test begins. Open the disc and close another end. Check the packing and other sealing parts weather it leaks after the pressure has been pumped up to the set value. Then close the disc, open the other end, check the ...
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In general, industrial valves don’t have to do a strength test in use. But repaired or corroded body and bonnet should do that. Common media used in valve pressure testing are water, oil, air, steam, nitrogen and so on. And valve pressure test methods of all kinds of industrial valves, including pneumatic, are as follows: 1.For ball valve The pneumatic test of the ball valve should be carried out ...
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Gate Valve is the most widely used one among all types of valves. Gate Valve, whose disc or wedge moves vertically along the axis of the channel, has the same basic function of other valves, turning on or turning off channels. In the pipeline, it is used as a piece to connect and cut off the media inside. What is worthy to be noted is that an ordinary gate valve usually opens or close pipeline com...
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1. What is the difference between Cast iron and Cast steel? The difference between Cast iron and Cast steel is their carbon content. Cast Iron with carbon content greater than 2.06% is iron; steel with carbon content between 0.02% and 2.06% is steel. 2. What is carbon steel? How many categories does it fall into? An alloy of carbon and iron (when the carbon content is between 0.02% and 2.06%) is c...
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1. What is the value of flow coefficient Kv? What is the flow coefficient Cv? Volumetric flow of water flowing between 5 ° C (40 ° F) and 40 ° C (104 ° F) through the valve to produce a pressure loss of 1 bar (14.7 psi), expressed in cubic meters per hour. Kv = Cv / 1.156 Flow coefficient Cv: It is the mass flow rate when water flows through the valve at 15.6 ° C (60 ° F) to produce 1psi, expresse...
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1. How do the pressures of ultra high pressure valves, high pressure valves, medium pressure valves, and low pressure valves differ? Ultra high pressure valve, nominal pressure PN≥100MPa; high pressure valve, nominal pressure PN10.0MPa-80.0MPa; medium pressure valve, nominal pressure PN2.5MPa-PN6.4MPa; low pressure valve PN≤1.6MPa. 2. How to distinguish the calibers of extra large caliber valves, ...
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People often have a confusion between a knife gate valve and slide gate valve. In brief, knife gate valve uses a blade to cut through thick liquids or gas; while a slide gate valve utilizes a slide plate to shut off flow of dry bulk material. In this article, we will discuss their differences in details. Knife Gate Valve Knife gate valves were originally designed for pulp and paper industry. ...
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