1) Drilling technology 
A tensioner is a device that applies a force to an object to maintain it in tension. Often the amount of force is adjustable. There are tensioners for applying a tensioning force to drive belts and chains, fibers, and bolts. One type of tensioner is a large industrial spring. A tensioner is used between two objects that should be kept together but...
tensioner A device for applying tension to cables, pipelines, etc.