The shut-off valve only allows the medium to flow in one direction, and it is directional during installation. The structural length of the globe valve is longer than that of the gate valve. At the same time, the fluid resistance is large. During long-term operation, the sealing reliability is not strong.
There are three types of globe valves: straight-through globe valves, right-angle globe valves and DC-type oblique globe valves.
The most obvious advantage is that during the opening and closing process, the friction between the valve disc and the sealing surface of the valve body is smaller than the gate valve, so it is wear-resistant. The opening height is generally only 1/4 of the diameter of the seat channel, so it is much smaller than the gate valve. Usually there is only one sealing surface on the valve body and valve disc, so the manufacturing process is better and it is easier to maintain.
Stop valve nominal pressure or pressure level: PN1.0-16.0MPa, ANSICLASS150-900, JIS10-20K, nominal diameter or caliber: DN10 ~ 500, NPS1 / 2 ~ 36, stop valve connection method: flange, butt welding, Thread, etc., applicable temperature: -196 ℃ ~ 700 ℃, globe valve driving mode: manual, bevel gear transmission, pneumatic, electric, hydraulic, gas-hydraulic linkage, electro-hydraulic linkage, valve body material: WCB, ZG1Cr18Ni9Ti, ZG1Cr18Ni12Mo2Ti, CF8 (304), CF3 (304L), CF8M (316), CF3M (316L), Ti. The stop valve is made of different materials.
The selection principle of globe valve is:
1. High temperature and high pressure medium pipelines or devices should use stop valves. Such as thermal power plant, nuclear power plant, petrochemical system high temperature, high pressure pipeline.
2. On the pipeline where the convection resistance is not strict. That is, where pressure loss is not considered.
3. Needle valve, instrument valve, sampling valve, pressure gauge valve can be used for small valves.
4. There are flow adjustment or pressure adjustment, but the accuracy of the adjustment is not high, and the diameter of the pipeline is relatively small, such as the nominal through the pipeline ≤ 50mm, it should be used.
5. Small chemical fertilizers and large chemical fertilizers in synthetic industrial production should use high pressure angle globe valve or high pressure angle globe valve with nominal pressure PN160 nominal pressure 16MPa or PN320 nominal pressure 32MPa.
6. In the desiliconization workshop and the coke-prone pipeline in the production of alumina Bayer method, it is easy to choose a DC-type globe valve or a DC-type globe valve with a separated valve body and a removable seat, and a hard alloy sealing pair.
7. In urban water supply and heat supply projects, nominally through smaller pipelines, stop valves, balance valves, or plunger valves can be selected, such as pipelines with nominally smaller than 150mm.