• Bolt diameters from 1 inch to 4 inch (standard range) and 1-1/2 inch to 3-1/2 inch (TSR spring return range)
• Maximum load from 233 kN on the T21 up to 2,629 kN on the T27
• 1500 bar maximum working pressure on every tool, pump and hose
• Each tool is a hydraulic cylinder, bridge, socket and puller, with CEJN quick connect fittings
• Hire the kit on its own, or with BLJ technicians to carry out the tensioning

A hydraulic bolt tensioner is a tool that loads a bolt by stretching it along its length with hydraulic pressure, instead of turning the nut against friction. Because the load goes straight into the bolt, thread and nut-face friction do not distort the result the way they can with torque.

How a tensioning pass works:

1. Fit. The bridge sits on the joint around the nut and the puller threads onto the exposed stud.
2. Stretch. Hydraulic pressure lifts the puller and stretches the stud to the calculated load.
3. Seat. With the stud held at load, the nut is run down onto the joint face through the bridge window.
4. Release. Pressure comes off, the stud tries to recover, and that load is now carried by the nut and clamping the joint.

Generally, half the studs on a flange are tensioned at the same time. This applies an even, accurate load to the gasket and gives the best chance of an effective long-term seal. Tensioning is commonly used on bolts 1-1/2 inch diameter and above, and on joints where gasket load matters most: pressure vessels, heat exchangers, critical pipework and LNG infrastructure.

Maximum working pressure is 1500 bar for every tool. Download the bolt tensioner data sheet (PDF)

Two columns decide whether a tool will physically fit. Nearest obstruction is the clear height the tool needs above the joint. Tool outside diameter decides whether tools sit side by side around the bolt circle when several studs are tensioned together.

TSR tensioners retract the piston automatically once the system is depressurised at the end of a tensioning sequence, so the tools are ready for the next pass straight away.

Nearest obstruction is listed per bolt size, in the same order as the bolt diameters. Maximum working pressure is 1500 bar for every tool. Download the TSR bolt tensioner data sheet (PDF)

Where clearance above the joint or spacing between studs is tight, send us the bolt size, flange details and available clearance and we will confirm which tool fits before the kit leaves our workshop.

A tensioner on its own does nothing. A working kit is the tools, the pump and the hoses, all rated to the same 1500 bar.

• The tensioners: each one a hydraulic cylinder, bridge, socket and puller
• Adaptor kits: interchangeable kits that fit common hydraulic cylinders, so one cylinder can tighten several bolt sizes
• The pump: air-driven hydraulic bolt tensioner pumps mounted in a compact tubular steel carrying frame
• Hoses and tee blocks: 5 metre link hoses, 1.5 metre interconnecting hoses and tee blocks from our range of 1500 bar tensioner hoses and T-blocks, so several tensioners run from one pump
• Fittings: CEJN quick connect fittings on every tensioner

Bolt tensioning generally provides greater accuracy and consistency than torque tightening, which makes it the preferred method for many critical joints and larger bolts. Torque tightening remains effective for many routine joints when it is carried out with calibrated equipment and controlled procedures.

The choice between bolt tensioning and torque tightening usually comes down to bolt size, how critical the joint is, and access. Tensioning also needs enough stud length above the nut for the puller to grip, so check stud protrusion before settling on the method. For joints where torque is the better fit, we also hire hydraulic torque wrenches.

You can hire bolt tensioners from BLJ In-situ Solutions and run them with your own crew, or have BLJ technicians carry out the work as part of our bolt tensioning services. Our controlled bolting team also provides bolt load calculations and flange stress analysis where the joint calls for it.

Tensioning is often one part of a wider scope. On a shutdown it regularly sits alongside flange joint management, and where a sealing face is damaged it is machined first with our flange facing machines so the gasket has a sound surface to seal against.

We support maintenance teams across Australia from our workshops in Brisbane and Gladstone, with bolting work extending to sites such as Karratha and Chinchilla.

BLJ In-situ Solutions is certified and registered by TQCS International Pty Ltd to ISO 9001:2015 Quality Management Systems standard. All work undertaken by our technicians is executed in accordance with its Quality Management System processes.