Technicians use a custom hydraulic tensioner (inset) to remove 3-m-long studs in a confined space.

Removing the studs was not only a difficult process, but also proved to be very lengthy as it required a lot of manpower. Further, the severe operating conditions corroded the studs. Given the confined location of the studs, PWCS discovered that they could not remove the studs with traditional removal equipment.

In previous stud-removal operations with traditional removal equipment, the company dedicated more than 20 hours to remove each stud and used up to 120 tons of force to push and pull a total of 16 studs. This process took more than 320 hours of labor to complete one job.

PWCS turned to Enerpac and the company designed a custom GT4 hydraulic tensioner for removing the studs in a safe and timely manner. Featuring six load cells and detachable and rotational bridges, the GT4 hydraulic tensioner simplifies bolting applications. Enerpac modified the height and puller sleeve of the tensioner to fit the confined space of the studs.

The custom GT4 hydraulic tensioner uses a ZUTP-Series hydraulic electric tensioning pump, which draws lower amps, making it optimal for use in remote locations. It also offers an adjustable valve to allow for safe and process pressure control. To accommodate the confined location of the studs, the electric tensioning pump features a compact, lightweight design to easily fit through tight openings.

The compact GT4 hydraulic tensioner expands vertically with hydraulic force to produce pulling power, which is applied to draw the studs through bushings. Prior to using the hydraulic tensioner, this process was extremely difficult and time-consuming.

Enerpac’s said its tensioner technology is ideal for applications requiring critical tolerances and multiple bolting and pulling tasks on heavy industrial equipment in a variety of industries. For large bolting applications, tensioners not only increase the accuracy of pulling forces, but can also simultaneously decrease the overall time required for the job, the company explained.

The hydraulic tensioner and pump allowed PWCS to pull each stud out in about 30 minutes, saving a significant amount of time for the maintenance team. In addition to time savings, Enerpac’s solution allowed the team to reduce labor and complete the job more efficiently and successfully.