Abstract: 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 may have an approximately constant force throughout its range of travel. The piston moves axially in response to the changing fluid flow rate to enable a constant amount of flow exiting the axial end of the tool to be achieved while diverting away excess flow through the side.

Abstract: 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.

Abstract: A snubber for reducing shock and vibration in down hole tools includes a housing having an axis and a chamber. A piston is mounted in the chamber for axial movement therein. The piston includes a shaft extending therefrom to an exterior of the housing. An axial spring element is mounted between the piston and the housing. Both the piston and the chamber include non-cylindrical portions.

Abstract: 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.