Pigging with Pig Ball Valves

The Batu Valve pig ball valve combines launching the pig, receiving the pig and shutting off the line in a single body. A pig is a device driven through a pipeline by the flow in order to clean or inspect the inside of the line.

A conventional pigging station is a launching and receiving arrangement consisting of a large barrel, isolation valves and auxiliary piping. It requires space and adds weight.

The pig ball valve combines these functions in a single valve body. Two valves are used on the line: one as launcher and one as receiver.

• CNC machined from forged steel.
• The ball is large and also accommodates long pigs.
• A guide prevents the pig from jamming.
• A pressure relief valve at the top, a liquid and sediment drain valve at the bottom and a pressure gauge in a visible position are provided.
• The closure has a mechanical safety lock that prevents opening under pressure.
• Owing to its DBB design it also serves as a normal shut-off valve.
• Designed to NACE for sour gas service.
• Receiver and launcher are supplied with a baffle and can be installed for left-hand or right-hand use.

1. The valve is closed. The body cavity is vented slowly; the pressure gauge is observed to fall to zero.
2. The entry closure is removed and the pig is placed in the ball cavity.
3. The closure is fitted; the vent and pressure relief valves are closed.
4. The valve is opened; flow and pressure drive the pig into the line.

1. The pig arrives at the valve. The body cavity is vented slowly; the pressure is observed to fall to zero.
2. The valve is closed.
3. The closure is removed and the pig taken out; the drain plug is opened and the sediment removed.
4. The closure is fitted, the vent valves are closed and the valve is returned to the flow position.

The maintenance procedure comprises 17 steps; their sequence is given in the instructions for use. Key points:

• Maintenance of the closure O-rings is critical: they are inspected at every opening and replaced if worn.
• The closure O-rings and machined surfaces are cleaned and lubricated with grease.
• The drive stem is lubricated once a year.
• If foreign matter enters between the ball and the seat and the surface is damaged, the leak is stopped temporarily by injecting sealant through the grease fittings on the closures.