YSJ hydraulic hammer jar is used to release drilling tools stuck in the well. The jar can produce large impact force for fishing and coring operations. According to the hydraulic principle, the elastic potential energy accumulated in the drilling tool during the hydraulic delay is suddenly released, which will produce a huge impact force. The main advantage of YSJ type hydraulic hammer is its simple structure. It provides powerful shock force, is easy to operate, and can be easily reset to the preload position for continuous shock. In order to obtain better shock effect, it is suggested to use YSJ Z-type jar together with zsj-type jar intensifier.

Working principle 

As the piston in the jar slowly moves up the cylinder, the working fluid (hydraulic oil) is pressured and compressed due to its slow out flowing rate. During this hydraulic time delay, elastic potential energy starts to accumulate in the drill tool. When the piston reaches the releasing bore, the hydraulic oil gushes out releasing the pressure, giving the piston a rapid upward load and releasing the elastic potential energy in the drill tool. When the jar pad hits the bottom of the up jar cylinder it creates an impact, this strong dynamic load is then transmitted to release the stuck drill tool. An important feature of this jar is the ease of closing  and resetting the tools for consecutive jarring.