When installing large-diameter fully welded ball valves, attention should be paid to key aspects such as pipeline pretreatment, lifting operations, welding specifications, and subsequent inspection and maintenance. The specific steps are as follows:

1. Pipeline inspection and pre-processing:

Before installation, it is necessary to ensure that the interior of the pipeline is clean, free of impurities, rust, etc., to prevent foreign objects from entering the valve. At the same time, it is necessary to check the size and positional errors of the pipeline to ensure that it matches the connection port of the ball valve.

2. Valve lifting:

The lifting rope should be tied to the lifting ear (ring) or flange on the ball valve body, avoiding tying to the handwheel, valve stem or actuator to prevent damage.

During the lifting process, the sealing covers at both ends of the ball valve should not be removed to prevent dust and foreign objects from entering the chamber.

Soft straps should be used for lifting to avoid impact or collision with the ball valve, and corner protection measures should be taken at the edges of the valve.

3. Valve inspection before installation:

Confirm the switch position of the ball valve, which should generally be in the fully open state.

Check if the valve cavity and sealing surface are clean. If there is any dirt, use a clean soft cloth to wipe it off.

Check whether the driving device is flexible, whether there is any jamming, whether the bolts and nuts are loose, and whether the packing is tightly compressed.

4. Welding of valves and pipelines:

Before welding, it is necessary to clean the surface of the pipeline and ball valve welds to remove impurities such as dust and oil stains.

During welding, the ball valve should be in the fully open position to prevent welding slag from entering the valve.

Before welding, cover the sealing surface area of the valve with protective tape to prevent splashes from falling in.

When welding, the corresponding welding process specifications should be followed to select the appropriate welding process and parameters.

Large caliber valves should be welded in sections according to a certain order to ensure welding quality and strength.

After welding is completed, the valve should be opened and closed only after it has completely cooled down.

5. Installation and commissioning of actuator:

For ball valves with actuators, the opening position of the actuator should be adjusted according to the valve switch position before installation to ensure that the direction indicated by the actuator arrow is consistent with the valve switch position. After installation, debugging is required to ensure that the actuator operates normally.

6. Post installation inspection and testing:

Check the quality of the weld seam to ensure that there are no defects such as missed welds, cracks, porosity, etc.

Conduct a sealing test to ensure that the valve is leak free.

Conduct operational testing to confirm that the valve operates flexibly and without any jamming.

7. Daily maintenance:

Regularly clean the surface stains of the ball valve to reduce the erosion of stains on the surface of the ball valve. Regularly activate the valve ball to reduce valve failures caused by external factors. Regularly clean the valve seat to reduce the accumulation of stains on the valve seat and prevent the flexibility of the valve seat components from weakening.