ZJS type jar extensifier is a downhole fishing jar designed to increase jaring force to up jar. Therefore, it must be run in conjunction with CSJ type super or YSJ type hydraulic up jar. It is to supply acceleration to the uper end of the jar during the free jarring stroke.Type Parameter ZSJ114B ZYSJ121B ZSJ146B ZSJ159B ZSJ178B ZSJ178B O.D. (mm) 114 121 146 159 178 203 I.D. (mm) 38 38 51 57 57 71 Overlength after pull 3340 3340 4000 4500 4000 4010 Stroke(mm) 250 250 330 330 310 330 Tensile load (KN),downhole 800 900 1200 1500 1800 2200 Max.work torque 4.9 7.8 15 19.6 23..5 Threads API NC31 NC38 NC40 Nc50 NC50 65/8”REG Sealing pressure 20 20 20 20 20
