I have a question for everyone: why is it necessary to remove air during the pressure test of valves? What are the consequences of not emptying it?
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I have a question for everyone: why is it necessary to remove air during the pressure test of valves? What are the consequences of not emptying it?
I think it’s for safety reasons. If there is air inside, the compressed air is released too slowly; what if that’s not suitable?
When pressurized with water, if the air is not removed, the pressure rises slowly.
The presence of air can affect the determination of voltage stabilization or pressure drop.
When pressing down, the filler leaked; after draining some water, it stopped leaking when pressing again. Could air be the cause?
When pressing down, the filler leaked; after draining some water, it stopped leaking when pressing again. Could air be the cause?
When the packing is soaked in liquid and then compressed, a proper seal is formed, preventing leaks. Sometimes, even a slight tightening of the screws or a change in the valve’s opening degree can determine whether there will be leaks or not; this is not a problem related to the size of the valve, as it can be resolved by replacing or adding more packing. The real problem is internal leakage within the valve, and if internal leakage is detected during pressure testing, the valve must be returned.
Internal leakage can also be measured in terms of volume; when it occurs in small-diameter valves, it seems quite severe, but in the case of large-diameter valves, it depends on the situation~~~~~ In fact, internal leakage in valves isn’t that dangerous; what’s really concerning is external leakage~~~~
Actually, just imagine: if a water seal is applied before the air has been exhausted, isn’t that compressing the air?
I cannot agree with this view; the hydraulic testing of valves is part of the inspection process when materials arrive at the factory. If strict controls are not applied during acceptance, then what’s the point of conducting such tests? If there is internal leakage during static low-temperature pressure testing, can it still be used after installation? Our standard is that if the internal leakage reaches 5%, the entire batch must be returned; if the external leakage is 1%, the entire batch must also be returned. Many unreputable valve manufacturers take advantage of this mindset to operate illegally, using second-hand components and refurbished old valves, passing off inferior products as good ones, and engaging in fraud and counterfeiting. As a result, the domestic valve manufacturing industry is unable to develop and progress over time.