Multistage Self-return Hydraulic Bolt Tensioner  BHD series multistage self-return hydraulic bolt tensioner The design of self-return plunger,Website:http://www.dudemachinery.com, double cylinder enables operation at narrow surroundings.  It is suitable for extending bolt of single specification easily with high accuracy.  It can be driven by both hand pump and pneumatic / electric pump. Several tensioners can work together simultaneously.  Application range: to tighten or loosen bolts of big machines in ship building plants, steel plants, fire power plants, wind power plants and nuclear power plants.  We design it as per the particular space on customer's machine.