1, stop valve
1) Direct-flow cut-off valve: In direct-flow cut-off valve or Y-shaped cut-off valve, the flow passage of the valve body and the main flow passage form a diagonal line, so the damage to the flow state is smaller than that of the conventional cut-off valve, and the pressure loss through the valve is correspondingly smaller.
2) Angle cut-off valve: In the angle cut-off valve, the fluid only needs to change direction once, so that the pressure drop through this valve is smaller than that of the conventional cut-off valve.
3) Plunger globe valve: This type of globe valve is a variant of the traditional globe valve.
2. Pinball valve
Functional classification:
1) Bypass valve: Generally, the ball valve is opened in still water, so the bypass valve is set to be pressurized first, that is, both sides are filled with water;
2) Air valve: when filling water, the air is removed and the valve is automatically closed with a float; When draining water, air is supplemented, and the buoy descends by itself;
3) Pressure relief valve: When opening and closing the valve, remove the pressure water between the valve and the sealing cover to avoid wearing the sealing cover;
4) Drain valve: Drain the sewage from the lower part of the spherical shell.
Second, the characteristics are different.
1, stop valve
1) globe valve is simpler in structure and more convenient to manufacture and maintain than gate valve.
2) The sealing surface is not easy to wear and scratch, and the sealing performance is good. In the process of opening and closing, there is no relative sliding between the disc and the sealing surface of the valve body, so the wear and scrape are not serious, the sealing performance is good and the service life is long.
3) When opening and closing, the disc stroke is small, so the height of the globe valve is smaller than that of the gate valve, but the structural length is longer than that of the gate valve.
2. Pinball valve
1) wear resistance; Because the valve core of the hard sealing ball valve is alloy steel spray welding and the sealing ring is alloy steel surfacing welding, the hard sealing ball valve will not produce too much wear when it is opened and closed.
2) Good sealing performance; Because the seal of hard sealing ball valve is polished by hand, it can only be used after the valve core and sealing ring are fully matched. So his sealing performance is reliable.
Third, the working principle is different.
1, stop valve
The closing principle of the globe valve is to make the sealing surface of the disc and the sealing surface of the valve seat closely fit through the pressure of the valve stem to prevent the medium from flowing. China's valve "three for one" once stipulated that the flow direction of the cut-off valve should be from top to bottom, so the installation is directional.
2. Pinball valve
A valve whose opening and closing parts (balls) are driven by the valve stem and rotate around the axis of the ball valve. It can also be used for fluid regulation and control. The V-shaped ball valve with hard seal has a strong shear force between its V-shaped ball core and the metal valve seat of hard-faced cemented carbide, which is especially suitable for media containing fibers and tiny solid particles.
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