The globe check valve is a valve that can cut off the fluid and act as a check valve, and the connection between the stem and the valve flap is designed to be disconnected.
Figure 1 shows the globe check valve to play the role of the check, in essence, is a lift check valve, its working principle, and lift check valve. When closing the valve, the stem moves downward to push the valve flap, so that the valve plays a closing role of the globe valve. When the valve is opened, the stem and valve flap are disconnected, and the valve flap can move up and down along the stem, which is equivalent to the lift check valve, when the fluid backflow, the valve flap can be closed under the action of self-weight and backflow pressure to prevent the media backflow.
The globe check valve shown in Figure 1 is essentially a swing check valve, and its working principle is the same as the swing check valve. When closing the valve, the stem moves downward to push the valve flap, so that the valve plays a closing role in the shut-off valve. When the valve is opened, the stem and valve flap are disconnected, and the valve flap can swing along the rocker axis, which is equivalent to the swing check valve, when the fluid backflow, the valve flap can be closed by itself under the action of self-weight and backflow pressure to prevent the backflow of media.
The Globe check valve combines the functions of the globe valve and check valve in one valve, so there is no need to add a stop valve after the check valve, which is especially suitable for the occasion where the installation position is restricted.
For the safe operation of a boiler plant, a shut-off check valve is as essential as any other safety valve or other safety facility attached to the boiler. Such valves are capable of performing important functions in boiler steam lines.
1. Can act as an automatic check valve to prevent steam from flowing backward from the main steam heater into the boiler.
2. It helps to cut off the boiler, and when the ceasefire is over, the valve flap automatically closes to prevent water heater pressure from entering the boiler.
3. It helps to bring the boiler steam into the application piping system after closing. This operation requires special care when performed manually, but with a shut-off check valve, it can be performed automatically without pressure fluctuations or water level disturbances.
4. The valve should be opened occasionally by maintenance personnel through a “safety first” valve that prevents steam from flowing backward from the water heater, or is used to shut off the piping during inspections or repairs.
If more than one boiler is connected to the main steam water heater, a shut-off check valve should be installed on the piping between each boiler and the water heater.
This valve should be installed so that the pressure in the boiler is located below the valve flap. Upright valves can be used in horizontal lines or vertical lines with upward flow. Angled valves can be used in upward horizontal or horizontal downward fluid lines.
The cylindrical valve is the only moving part. It is a basic construction that produces maximum lift force at minimum flow rates. There are no flanking guides, so there is no “rotational” force to accelerate wear.
The long throttle sleeve is located on the valve flap and stops the decelerating fluid as it approaches the seat seal position, thus preventing fluttering of the valve flap and reducing pulling of the seat seal surface.
The removable bushing guides the valve flap throughout the stroke. This component is completely independent of the valve body, so it is not subject to expansion stresses that can deform it.
The piston ring’s enhanced damper performance prevents rapid movement of the valve flap, which may require the installation of two piston rings if the pulsation phenomenon is particularly strong.
The easily grindable tapped hub is located on top of the valve flap, allowing the insertion of a nozzle or tapped bolt to facilitate rapid removal of the valve flap for grinding.
The extra large port area is located within the valve cavity, allowing minimal pressure drop through the valve and ensuring the unrestricted movement of the valve flap.
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