SYSTEM, METHOD AND APPARATUS FOR CONTROLLING FLUID FLOW THROUGH DRILL STRING

摘要

A device for limiting the flow of drilling fluid through a section of drill string includes a body with a hole in the periphery. Flow enters the device through one axial end, at least a portion of the flow exits through the other axial end. Some of the fluid flow can be diverted through the peripheral hole. A spring-biased axial piston has an approximately constant force throughout its range of travel. The piston moves axially in response to the changing fluid flow rate to ensure that a constant amount of flow exiting the axial end of the tool is achieved while diverting away excess flow through the side.