Method and device to allow a rigid pig to pass into a flow pipe which requires the use of a hollow flow-constricting device

摘要

There is disclosed a method and a device to allow a "rigid" pig to pass into an undersea flow pipe in which a hollow flow-constricting device is in use. According to the invention the device is provided with a first pipe branch and a second pipe branch. The first pipe branch is provided with a hollow flow-constricting device in it and both first and second pipe branches are provided with shut-off valves, whereby the flow can be diverted to the second pipe branch thereby enabling a rigid pig to pass into such second pipe branch, when necessary.