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Gate valve and globe valve selection and difference
The gate has two sealing surfaces. The two sealing surfaces of the more commonly used wedge gate valve form a wedge shape. The wedge angle varies with the valve parameters, usually 5o. The gate of the wedge gate valve can be made into a whole, called a rigid gate; it can also be made into a gate that can produce a small amount of deformation to improve its craftsmanship and make up for the deviation of the sealing surface angle during processing. The plate is called an elastic gate.
When the gate valve is closed, the sealing surface can be sealed only by the medium pressure, that is, relying on the medium pressure to press the sealing surface of the gate to the valve seat on the other side to ensure the sealing of the sealing surface, which is self-sealing. Most gate valves are forcibly sealed, that is, when the valve is closed, the gate must be forced against the valve seat by external force to ensure the tightness of the sealing surface.
Gate valve advantages:
1.Opening and closing is more labor-saving.
2.The flow direction of the medium is not restricted, the flow is not disturbed, and the pressure is not reduced.
3.The fluid resistance is small, and the sealing surface is less eroded and eroded by the medium.
4. The shape is simple, the length of the structure is short, the manufacturing process is good, and the scope of application is wide.
Nominal pressure or pressure level: PN1.0-16.0MPa, ANSI CLASS 150-300LB, JIS10-20K
Nominal diameter or diameter: DN10~1000, NPS 1/2~36″
Connection method: flange, butt welding, thread, etc.
Applicable temperature: -196℃~700℃
Drive mode: manual, bevel gear drive, pneumatic, electric, hydraulic, gas-liquid linkage, electro-hydraulic linkage
Body material: WCB, ZG1Cr18Ni9Ti, ZG1Cr18Ni12Mo2Ti, CF8(304), CF3(304L), CF8M(316), CF3M(316L), Ti. Choose different materials, can be applied to water, steam, oil, nitric acid, acetic acid, oxidizing medium, urea and other media. Globe valve refers to a valve in which the closing member (disc) moves along the centerline of the valve seat. According to this moving form of the valve disc, the change of the valve seat port is proportional to the valve disc stroke. Because the valve stem of this type of valve has a relatively short opening or closing stroke, and has a very reliable shut-off function, and because the change of the valve seat port is proportional to the stroke of the valve disc, it is very suitable for flow regulation. Therefore, this type of valve is ideal for shut-off or regulation as well as throttling.
Selection principle:
1. A globe valve should be selected on the pipeline or device of high temperature and high pressure medium. Such as thermal power plants, nuclear power plants, high temperature and high pressure pipelines of petrochemical systems.
2. On pipelines where the requirements for convection resistance are not strict. That is, where the pressure loss is not considered.
3. Small valves can choose needle valve, instrument valve, sampling valve, pressure gauge valve, etc.
4. There is flow adjustment or pressure adjustment, but the requirements for adjustment accuracy are not high, and the diameter of the pipeline is relatively small, such as the pipeline with a nominal diameter ≤ 50mm, it should be selected.
5. Small fertilizers and large fertilizers in synthetic industrial production should choose high pressure angle globe valve or high pressure angle throttle valve with nominal pressure PN160 nominal pressure 16MPa or PN320 nominal pressure 32MPa.
6. In the desiliconization workshop and the pipelines prone to coking in the production of alumina Bayer method, it is easy to choose the DC type globe valve or DC type throttle valve with separate valve body, removable valve seat and cemented carbide sealing pair.
7. In the water supply and heating projects in urban construction, the nominal passage is smaller, and the cut-off, balance valve or plunger valve can be selected, for example, the nominal passage is less than 150mm.
advantage
During the opening and closing process, the friction between the valve disc and the sealing surface of the valve body is smaller than that of the gate valve, so it is wear-resistant. The opening height is generally only 1/4 of the diameter of the valve seat passage, so it is much smaller than the gate valve. Usually there is only one sealing surface on the valve body and the valve disc, so the manufacturing process is better and it is easy to maintain.
Nominal pressure or pressure level: PN1.0-16.0MPa, ANSI CLASS 150-900, JIS10-20K
Nominal diameter or diameter: DN10~500, NPS 1/2~36″
Connection method: flange, butt welding, thread, etc. Applicable temperature: -196℃~700℃
Drive mode: manual, bevel gear drive, pneumatic, electric, hydraulic, gas-liquid linkage, electro-hydraulic linkage
Body material: WCB, ZG1Cr18Ni9Ti, ZG1Cr18Ni12Mo2Ti, CF8(304), CF3(304L), CF8M(316), CF3M(316L), Ti. Choose different materials, can be applied to water, steam, oil, nitric acid, acetic acid, oxidizing medium, urea and other media.
The above is the selection and difference between gate valve and globe valve that I shared with you today. I hope it will be helpful to you. Collect it~
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