Importance

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Abstract

Disclosed is a bidirectional fluid operated jarring apparatus. The apparatus includes a tubular body having a lower end defining a downwardly facing body hammer. A tubular knocker sub is axially slidingly mounted to the body adjacent the body hammer and includes an upwardly facing anvil engageable with the body hammer and spaced apart oppositely facing internal hammers, the upper one of which defines an internal anvil. A tubular mandrel having a low passage therethrough is axially movably mounted in the body and knocker sub. The mandrel includes a hammer positioned within the knocker sub between the internal shoulders. A valve is provided for closing the mandrel flow passage so that fluid pressure urges the mandrel axially downwardly with respect to the body and opening the mandrel flow passage upon predetermined downward movement of the mandrel. When the knocker sub is in a retractive position, the apparatus produces a downward jarring force. When the knocker sub is in an extended position, the apparatus produces an upward jarring force.

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First Claim