Single Stage vs. Multi-Stage Tensioner

Single Stage hydraulic tensioners are ideal for applications that are vertically limited. They provide a large amount of stroke in a vertically compact package.

In a radially limited environment, the presence of other studs or other obstructions nearby limits the workable diameter of the hydraulic tensioner. By stacking multiple radially compact stages one over the other, and linking them with internal hydraulic coupling, the multiple stages of a multi stage hydraulic tensioner work together to provide more load than a single stage of the same size and provide. 

Another solution for radially limited environments, where space limitations only exist in one dimension, such as a wind turbine foundation stud where the mast is close to the stud, is an elliptically hydraulic tensioner. Elliptical hydraulic tensioners provide the large surface area required to generate the load on two elongated sides of the tensioner, providing low clearance on the other two sides.