CPC B25D 9/125 (2013.01) [B25D 2250/125 (2013.01); E21B 31/113 (2013.01)] | 21 Claims |
1. A fluid driven pulsating, hammering tool operational when pressurized fluid is pumped into an upper sub of said tool, comprising:
a poppet valve having a valve seat which can seal the upper end of a slidable outer valve assembly when closed thereby generating back pressure waves in the pressurized fluid which intermittently reduce the fluid pressure in the poppet valve such that it intermittently opens the valve seat;
an inner valve assembly slidable within the outer valve assembly;
wherein the inner and outer valve assemblies remain in selective fluid communication with the poppet valve even when the poppet valve is closed, wherein interruption of said fluid communication occurs from movement of the inner and/or outer valve assemblies to particular positions along their sliding paths, such that said interruption also generates back pressure waves in the pressurized fluid which intermittently reduce the fluid pressure in the poppet valve;
further including a lower back pressure valve having at least one channel curved with respect to a longitudinal axis of said tool, and wherein there is a fluid path from said channel directly to the poppet valve, and a second flow path from said channel to the inner valve assembly and to the outer valve assembly such that said outer valve assembly can be positioned closed to prevent access from the channel to the poppet valve other than through the outer valve assembly, and wherein when positioned closed, the channel remains in fluid communication with the inner and outer valve assemblies, and whereby said lower back pressure valve intermittently generates back pressure waves which intermittently reduce the fluid pressure in the poppet valve.
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