Tapping valves are used to isolate media within the existing line while an additional connection is made. Some tapping valves are designed to be used while the line is under working pressure and in operation, eliminating system downtime.
Tapping valves are installed using a variety of techniques, including hot tapping, wet tapping, line stopping or plugging, or pipe freezing. Other applications use tapping valves for installing flow meters, probes, or control valves into an existing line. Tapping valves may be installed using a hot tap or a wet tap technique. A hot tap or a wet tap is installed using a pressure-contained tapping machine to attach a tapping valve to the existing pipeline. Hot tapping uses a nozzle or split tee welded to the surface of the existing pressurized pipe. Hot taps are used in refineries, heating and cooling applications, and steam lines. Wet taps use a tapping sleeve that is bolted to the existing pipeline to make a branch connection. Wet tapping is used on sewer or water systems.
Tapping valves may also be used to install other system valves, such as a ball or gate valve, into an existing main or pipeline. Using a tapping machine, defective valves can be replaced, or a flow control valve or flow monitoring meter can be installed without shutting down the whole system. Installing flow meters or other sensors involves the use of a tapping machine and an isolation valve. An isolation valve is used in hot tapping applications to provide an isolated environment within the pipeline for adding valves or sensors or to redirect the flow through a bypass section of pipe. A swedge tapping valve is a type of hot tapping valve that enables the tapping of butterfly valves and adding new connections to existing pipelines without interrupting the flow in the line.