What are the selection methods of shut-off valves?
The shut-off valve refers to the valve whose closing part (disc) moves along the center line of the valve seat. According to this movement form of the valve disc, the change of the valve seat port is proportional to the valve disc stroke. The opening or closing stroke of the valve stem of the shut-off valve is relatively short, and it has a very reliable shut-off function. Also, because the change of the valve seat port is proportional to the stroke of the valve disc, it is very suitable for flow adjustment. Therefore, the shut-off valve is very suitable for use as a shut-off or adjustment and throttling.
Selection principle of globe valve:
1. Imported stop valves should be used on pipelines or devices for high temperature and high pressure media. Such as thermal power plants, nuclear power plants, high-temperature and high-pressure pipelines of petrochemical systems. Select chromium molybdenum steel, chromium molybdenum vanadium steel, alloy steel and other high temperature and high pressure globe valves.
2. On pipelines that do not require strict convection resistance. That is, where the pressure loss is not considered.
3. For small-caliber stop valves, needle valves, instrument valves, sampling valves, pressure gauge valves, etc. can be used. Generally use stainless steel 304, 316 material.
4. There is flow adjustment or pressure adjustment, but the adjustment accuracy is not high, and the pipe diameter is relatively small, such as the pipe with a nominal passage of ≤50mm, it should be selected.
5. Small fertilizers and large fertilizers in synthetic industrial production should use high pressure angle type inlet stop valves or high pressure angle type inlet stop valves with a nominal pressure of PN160 and a nominal pressure of 16MPa or PN320 and a nominal pressure of 32MPa.
6. In the desiliconization workshop of the alumina Bayer process and the pipelines that are prone to coking, it is easy to choose the direct-flow imported stop valve with the valve body separated, the valve seat can be removed, and the cemented carbide sealing pair.
7. For water supply and heating projects in urban construction, smaller pipelines are nominally passed through, and stop valves, balance valves or plunger valves can be selected, such as pipelines whose nominal diameter is less than 150mm.
8. For occasions with higher sealing requirements, such as hydrogen, methane, toluene, oxygen, nuclear industry, and Steam Pipelines with higher requirements, you can choose a double-sealed bellows stop valve.