Wwt North America Holdings, Inc.

Eric John O'Neal

Rudolph Ernst Krueger, V

Andrew Trowbridge

A clean out sub for use in a drill string having a tool body with a cavity for passage of drilling fluid and annular fluid circulation ports extending through the tool body, a valve spool is positioned within the tool body cavity having a reduced diameter orifice, a compression spring is located within the tool body cavity adjacent the valve spool, wherein a drop in fluid pressure created by the orifice imparts a downhole force on the valve spool and at a predetermined force overcomes a set resistive force of the compression spring thereby moving the valve spool to open the annular fluid circulation ports.

Clean out sub

A down hole drilling tool for preventing overpressure strain on surface pumping equipment or a down hole drilling motor having a housing and a circulation port and four hydraulic valves positioned on the housing actively working together to effectively open the circulation port to drilling annulus at a high pressure setting and dose the circulation port to annulus at a low pressure setting, the four hydraulic valves include a high pressure setting valve, a low pressure setting valve, a control valve and a fixed setting valve.

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Mission Viejo, CA, United States of America

Eric John O'Neal