ACOUSTIC MULTIFREQUENCYTRANSMITTER AND METHOD FOR UNDERWATER PIPELINE INSPECTION GAUGES

摘要

A multiple frequency ping transmitter which can be carried by a pig which is used in an underwater pipeline. The ping transmitter produces a ping chord which includes a plurality of different tone frequencies which are simultaneously transmitted in the ping chord. Procedures are also provided wherein the multiple frequency ping transmitter is used in a system and method for located a pig which is stuck in the underwater pipeline or for determining the relative velocity of a moving pig.