The use of stop valves is extremely widespread, with a vast variety of types available. The main categories include bellows-type stop valves, flanged stop valves, internal-threaded stop valves, stainless steel stop valves, straight-through stop valves, needle-type stop valves, Y-type stop valves, angle-type stop valves, insulated stop valves, cast steel stop valves, and forged steel stop valves. Selecting the right type is crucial, as it requires consideration of medium characteristics, temperature, pressure, and operating conditions.
The specific selection criteria are as follows:
It is advisable to use pneumatic stop valves on pipelines or equipment handling high temperature and high-pressure media, such as on high temperature and high-pressure pipelines in power plants and petrochemical systems.
In pipelines where strict upstream resistance is not required, direct-acting shut-off valves should be used.
3. The small pneumatic shut-off valves can be optionally selected with needle valves, gauge valves, sampling valves, pressure gauge valves, etc.
4. Flow or pressure regulation is available, but with a lower precision requirement. Moreover, the pipeline diameter is relatively small, such as on pipelines with a nominal diameter of ≤ 50mm, pneumatic gate valves and electric regulating valves can be selected.
5. Select a thermal cut-off valve for media that tend to solidify and crystallize easily.
6. Choose forging stop valves for ultra-high-pressure environments.
In the production of synthetic industries, it is recommended to use high-pressure angle type stop valves or high-pressure angle type throttle valves with nominal pressure PN160 (16 MPa) or PN320 (32 MPa) for small and large chemical fertilizers.
In the desilication workshop of the Bayer process for alumina production, and on pipelines prone to coking, it is advisable to choose direct-acting stop valves or throttle valves with a separable valve body and removable valve seats, equipped with hard alloy sealing pairs.
In urban construction for water supply and heating projects, pipelines with a nominal diameter smaller than 150mm can utilize pneumatic gate valves, balancing valves, or plunger valves.
10. For high-temperature steam and toxic/hazardous media, choose an imported bellows-type stop valve.
11. Choose stainless steel or lined fluorine stop valves for acidic and alkaline cutoff valves.
