If your project has strict requirements on bolt pre-tightening force, conventional tensioning tools will not be able to meet your needs, then bolt tensioner will be your perfect choice. The bolt stretcher is very suitable for the connection of high-pressure sealing flanges. When the tensioning of bolts by the bolt tightener machine, the bolt is directly elongated by pure tension, without torsion, shear and lateral force, and no frictional damage to the contact surface of the connection. It is the best method to accurately control the pre-tightening force of the bolt. With the hydraulic bolt tensioner, you can pre-tighten or disassemble multiple bolts at the same time, with uniform distribution, safe and efficient, and is one of the best bolt tensioning tools. TorcStark has many years of research and manufacturing experience in bolt stretcher. As one of the world’s best bolt tensioner manufacturers and suppliers, TorcStark hopes to provide you with the most suitable bolt stretcher. Therefore, if you want to buy a bolt tensioner or want to know the price of a bolt stretcher, please contact us by email, phone, or online support. TorcStark will provide you with product brochures, bolt tensioner price lists and the best bolt solutions!
A: Basically there are two types, single stage bolt tensioner (also called topside bolt tensioner) and multi stage bolt tensioner. But customized models are also available.
A: In most cases single stage bolt tightener machine is required for example oil&gas, petrochemical industry etc. For multi stage tensioner it’s specially used for wind turbine installation and maintenance.
A: If any customer wants a hydraulic tensioning of bolts, you’re kindly requested to provide necessary information as mentioned below:
- What is the maximum tensile force you need?
- What are your bolt sizes? M39 M42 or else?
- What is the strength grade of the bolt? Usually it’s 10.9 or 8.8. If you don’t know the answer for Question 1, then this one is very necessary to answer.
- Do you need topside or multi stage bolt tightening tools?
A: Please show us the model number and picture of your old model, then we will recommend the similar.
A: In this case it is suggested that you just need drop us an email (ID: TorcStark@gmail.com) and our sales representative will guide you to fill in a questionnaire, with this form we will recommend the suitable model for you.
hydraulic bolt tensioner video
What is a bolt tensioner?
Bolt tensioner is a bolt pre-tightening and disassembly tool. It is like a ring jack installed on bolts and nuts. With the help of hydraulic power provided by tensioner pumps, the bolts are stretched in the elastic deformation zone according to the allowable elasticity of the material to achieve the purpose of tightening or removing the bolts. The biggest advantage of the tensioning of bolts is that multiple bolts can be fastened and disassembled at the same time. The distribution force is even. It is a safe, efficient and fast tool, and it is the best way to fasten and disassemble bolts of various specifications.
Generally speaking, tensioning machine are also called bolt tensioners, hydraulic tensioners, and bolt stretcher and so on.
How does a hydraulic bolt tightening machine work?
The thread friction between the nut and the washer consumes more than 80% of the torque energy on the nut or bolt, leaving less than 20% of the energy to produce effective tension on the bolt shank.
This change in friction loss, from one bolt to another, causes uneven tension on the bolts, so a bolt tensioning tools has appeared to solve this problem.
The hydraulic tensioning tool is generally composed of a hydraulic tensioner pump, a high-pressure hose, a pressure gauge and a stretching body. The hydraulic tensioning pump is the power source, the pressure gauge reflects the output pressure of the pump, and the high-pressure hose is connected to the hydraulic tensioner pump and the stretching body.
Stretching body is an executive element that realizes bolt stretching. It is mainly composed of a piston cylinder, a piston, a supporting bridge and a tension nut.
When working, the high-pressure oil output by the power source is delivered to the piston cylinder through the high-pressure hose, and the piston in the piston cylinder moves upward under pressure, driving the tension nut to move upward.
The tension nut is threadedly connected with the working bolt. With the extension tension generated by the hydraulic source provided by the ultra-high pressure oil pump, and the extension force determined by the material’s tensile strength, yield coefficient and elongation rate, the bolt tensioning equipment exerts force on the bolt to elongate it in the elastic deformation zone.
At this time, the bolt diameter is slightly deformed, the working bolt is elongated, the bolt elongation reaches the required deformation, and the deformation is controlled within the elastic deformation range, and the pre-tightening or disassembly operation can be carried out. Finally, return the working bolt to its original shape by hydraulic or mechanical return.
The hydraulic nut tightener is like a ring jack mounted on bolts and nuts. The jack pushes the bolt connection and pulls the end of the bolt. The diameter of the bolt must be at least one longer to accommodate the bolt tensioning tool.
Since the force generated by the jack directly acts on the end of the bolt, a tension equal to the load generated by the jack is generated in the bolt shank.
In the case of tension applied by the jack, the nut can be rotated with zero torque until it is tightened.
Then the load applied by the jack is relaxed, and is retained in the bolt shank according to the high percentage of bolt length and diameter, so as to realize the pre-tightening or disassembly of the bolt.