A hydraulic bolt tensioner is a ring jack that fits over the bolt and nut to be tightened. The jack pushes into the bolted joint and pulls the end of the bolt, which must be at least one longer in diameter to accommodate the bolt tension tool. Bolts provide tensile force to hold items in place. This tension must be within approximately 80 percent of the bolt’s ultimate tensile strength to maintain proper mechanical tension safely. The bolt tensioning equipment involves using mechanical means to stretch the stud bolt physically. The material will stretch when the nut is placed on the bolt. Once the nut is in place, tension is released when the stud bolt metal returns to its original shape before stretching. This process is called spring tension when the bolt returns to its original state.
Usage of Hydraulic Bolt Tensioner:
When choosing a hydraulic bolt tensioner, you must analyze various characteristics. Following are the uses of tension adjustment. You should evaluate the bolt diameter, nut size, bolt grade, thickness, and washer diameter. Protruding the length of the free stud and the bolt’s load requirements, you can then check the technical specifications of the hydraulic bolt tensioning equipment. This will ensure it provides the proper hydraulic pressure to achieve the desired rate. Preload is also required for them. This will help the tensioning tool to provide tight to large-diameter bolts quickly and easily.
Procedure for Adjusting Hydraulic Tension:
- First, place the bolt tensioner over the free part of the stud bolt until it contacts the flange.
- Thread a tensioner puller onto each load cell to connect it to the cylinder piston.
- Each tensioner is connected to a hydraulic pipe.
- Use specified hydraulic pressure to preload the stud bolt as it begins to stretch.
- The tensioner has a locking collar that turns using a tommy bar to push the nut on the joint.
- Turn the nut down onto the face of the joint until it snaps into place.
- Release the pressure on the hydraulic bolt tensioner.
When the hydraulic bolt tensioner releases pressure and is removed, the tension created on the stud bolt is removed. Same as spring, it returns to its normal shape by shrinking. It clamps onto the joint to create a correct seal.
Types of Hydraulic Bolt Tensioning Systems:
There are two types of bolt tensioning systems. There are systems where all the nuts are tensioned at once, and the others are tensioned half at once, followed by the other half immediately after. Tightening all the bolts at once will speed up the process. But it can damage damaged bolts when you do half and half. A damaged bolt will not cause immediate problems because the other half is still in place. This makes it easier to identify and replace damaged bolts and achieve the most appropriate level of tension. They fit the stud, loosen the nut, and apply tension to the bolt. When the appropriate level of tension is reached, Nuts are tightened to appropriate torque specifications. This will give you the optimal level of tension for each bolt and the best mechanical application for your machine.