QJZ MECHANICAL DRILLING JAR

Working principle 

● Up Jarring 

Up Jarring is achieved by pulling the drill string until it reaches the jar trip  load. The jar trip load will cause the internal spring unit to deform, allowing  the trip sleeve to engage the friction sleeve. When this happens, the mandrel  is suddenly freed to release the jarring force. To reset the jar, remove the pull  load by lowering the drill string.  

● Down Jarring 

There is another set of internal spring sleeve located at the top of the slips. Down Jarring is achieved by lowering(pushing) the drill string until it reaches  the jar trip load. The jar trip load will cause the internal spring unit to deform, allowing the trip sleeve to engage the friction sleeve. When this happens, the mandrel is suddenly freed to release the jarring force. To reset the jar, remove the downward load by pulling the drill string.