Valve for a two way hydraulic drilling jar and a two way hydraulic drilling jar

摘要

A valve for a two way hydraulic drilling jar which includes a hollow cylindrical member having an exterior surface, an interior surface, a first end and a second end. At least one spiral-form fluid bypass passage is positioned in each of the first end and the second end of the cylindrical member. The at least one spiral-form bypass passages has a first end communicating with the exterior surface and a second end communicating with the interior surface.