What are the performance and characteristics of globe check valve?

What are the performance and characteristics of globe check valve?

The stop check valve is a valve that can cut off the fluid and play a check function. The connection between the valve stem and the valve disc is designed to be detachable.

 

What is a lift check valve?

When the stop check valve shown in Figure 1 plays a check function, it is essentially a lift check valve, and its working principle is the same as that of the lift check valve. When the valve is closed, the downward movement of the valve stem can push the valve disc, so that the valve acts as a shut-off valve. When the valve is opened, the valve stem is disengaged from the valve disc, and the valve disc can move up and down along the valve stem. At this time, it is equivalent to a lift check valve. When the fluid flows back, the valve disc can automatically close under the action of its own weight and reverse flow pressure. , to prevent the backflow of the medium.

 

What is a swing check valve?

When the stop check valve shown in Figure 2 plays a check function, it is essentially a swing check valve, and its working principle is the same as that of the swing check valve. When the valve is closed, the downward movement of the valve stem can push the valve disc, so that the valve acts as a shut-off valve. When the valve is opened, the valve stem is disengaged from the valve disc, and the valve disc can swing along the rocker shaft, which is equivalent to a swing check valve. Close to prevent backflow of media.

 

The stop check valve combines the functions of the stop valve and the check valve on one valve, so there is no need to add a shut-off valve after the check valve, which is especially suitable for occasions where the installation position is limited.

 

For the safe operation of the boiler plant, the stop check valve is as essential as other safety valves or other safety facilities attached to the boiler.

 

This valve performs important functions in boiler steam lines:

1. It can be used as an automatic check valve to prevent the steam from flowing back from the main steam heater to the boiler.

2. It helps to cut off the boiler. When the fire is stopped, the valve flap is automatically closed to prevent the pressure of the water heater from entering the boiler.

3. Helps to bring boiler steam into the application piping system after shutdown. This operation requires special care when performed manually, but can be performed automatically with a globe check valve without pressure fluctuations or water level disturbances.

4. Maintenance personnel should occasionally open the valve through a "safety first" valve that prevents steam from flowing back from the water heater, or is used to close the line during inspection or repair.

 

If more than one boiler is connected to the main steam water heater, a shut-off check valve should be installed on the line between each boiler and the water heater.

 

The valve should be installed so that the pressure in the boiler is below the valve disc. Upright valves can be used on horizontal pipelines or vertical pipelines with upward flow. Angle valves can be used on fluid lines running horizontally up or down.

 

The cylindrical disc is the only moving part. This is a basic structure capable of producing maximum lift force at minimum flow rate. There are no flanking guides, so there is no resultant "rotational" force that increases wear.

 

The long throttle sleeve is located on the valve disc, which can prevent the deceleration fluid when the fluid is close to the seat sealing position, thereby preventing the valve disc from vibrating and reducing the wire drawing of the valve seat sealing surface.

A removable bushing guides the disc throughout its stroke. This part is completely independent of the valve body, so it will not be deformed by expansion stress.

The performance of the shock absorber reinforced by the piston rings prevents rapid movement of the valve disc, if the pulsation is particularly strong, it may be necessary to install two piston rings.

 

An easy-to-regrind tapped hub sits on top of the disc, allowing nozzle or hole bolt insertion, facilitating quick disc removal for grinding.

The extra large port area is located within the valve cavity to minimize pressure drop across the valve, ensuring unrestricted movement of the disc.

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