SHIFTING MECHANISMS FOR FLUID JET DECOKING TOOLS

摘要

A mode shifting apparatus for a decoking tool. A diversion plate can be used to provide selective delivery of a pressurized decoking fluid to one or the other of nozzles in the tool. The mode shifting apparatus can be used to switch between a cutting mode of operation and a drilling mode of operation by rotation of the diversion plate, where a biasing force causes the diversion plate to unseat itself from an adjacent surface of the tool in order to reduce friction forces between them. The diversion plate may be temporarily unseated from an adjacent surface of the mode shifting apparatus prior to relative rotation between them such that both rotationally-induced forces and the need for relying upon a lubricating fluid to achieve damping between adjacent component surfaces may be reduced.