About hydraulic bolt stretcher, also called hydraulic nut, is an advanced bolt assembly method, especially suitable for fastening of narrow space and heavy-duty vibration machinery. Its main components include sliding piston, oil cylinder, support ring, sealing ring, air release screw and quick joint, etc. The working principle of the hydraulic bolt stretcher is that the internal thread of the sliding piston is put into the thread of the upper part of the bolt, and the high-pressure oil from the hydraulic oil pump is connected to the sealing space formed by the oil cylinder and the sliding piston through the quick joint. The hydraulic oil acts on the sliding piston, so that the sliding piston exerts an external force on the bolt for axial stretching, and the bolt with the applied force is pulled in its elastic deformation area When the bolt is lengthened, tighten the nut, so that the bolt will be locked in the lengthened position.

The sliding piston can slide up and down in the cylinder, and the upper and lower sealing rings can prevent internal hydraulic oil leakage. Each hydraulic stretcher has a large lift. If the lift is exceeded during operation, the high-pressure oil will leak through the lower sealing ring, resulting in the pressure drop of the hydraulic oil in the sealing space. There are two seals, one is rectangular, the other is circular.
The lower part of the support ring has two grooves, which are used to measure the movement distance of the nut. The load applied to the bolt is proportional to the oil pressure in the hydraulic cylinder, so the design can retain the payload very precisely.

The hydraulic stretcher has many advantages:
1. The drawing mode is not affected by the bolt lubrication effect and the thread friction size, and more accurate bolt load can be obtained.
2. Multiple bolts can be stretched synchronously to make the whole circle of bolts bear even force and get balanced load.
3. With advanced ultra-high pressure technology, the bolt can be locked in a small space.
4. The residual load and effective load obtained by tightening the bolt in the tensile mode are larger than that in the torque mode.
5. Economic efficiency, light weight and high precision.

BTS Series, Hydraulic Bolt Tensioning Tools Bolt Range:3/4″- 4″ M20-M100 Load Capacity:18-312 tons Stroke:0.6inch Max. Operating Pressure:21,750psi Light weight and compact structure suits operations in small space. Special steel body and advanced surface treatment with perfect rust and corrosion resistance. Strong versatility and high adaptability. Synchronous […]