Tensioner
Encyclopedia
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, fiber
s, and bolt
s.
One type of tensioner is a large industrial spring
. A tensioner is used between two objects that should be kept together but that make relative, more or less unpredicted, motions towards each other. The tensioner makes sure that independent of the motion the connection remains intact, without elements becoming overstressed. An anchor chain
could be defined as the easiest tensioner.
Most tensioners can be described as industrial springs. A marine riser tensioner on board a drill ship, for instance, consists of two sheaveblocks
with a wire over it. Both sheaveblocks are connected by a hydraulic cylinder and the oil of the hydraulic cylinder is connected to a gas volume under pressure. When the wire rope is connected to a riser, the wire rope is kept under a certain stress, so that the riser does not buckle. If the ship moves up and down, the tension in the wire rope is changed a bit (depending on the spring characteristic).
Force
In physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a flexible object to deform...
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, fiber
Fiber
Fiber is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread.They are very important in the biology of both plants and animals, for holding tissues together....
s, and bolt
Bolt
-Fasteners:*A cap screw, as used in a bolted joint*Screw, a cylindrical threaded fastener*Dead bolt, a kind of locking mechanism*Bolt , an anchor point used in rock climbing-Weaponry:*Bolt , a mechanism used in firearms...
s.
One type of tensioner is a large industrial spring
Spring (device)
A spring is an elastic object used to store mechanical energy. Springs are usually made out of spring steel. Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel and hardened after fabrication...
. A tensioner is used between two objects that should be kept together but that make relative, more or less unpredicted, motions towards each other. The tensioner makes sure that independent of the motion the connection remains intact, without elements becoming overstressed. An anchor chain
Anchor
An anchor is a device, normally made of metal, that is used to connect a vessel to the bed of a body of water to prevent the vessel from drifting due to wind or current. The word derives from Latin ancora, which itself comes from the Greek ἄγκυρα .Anchors can either be temporary or permanent...
could be defined as the easiest tensioner.
Most tensioners can be described as industrial springs. A marine riser tensioner on board a drill ship, for instance, consists of two sheaveblocks
Block (sailing)
In sailing, a block is a single or multiple pulley. One or a number of sheaves are enclosed in an assembly between cheeks or chocks. In use a block is fixed to the end of a line, to a spar or to a surface...
with a wire over it. Both sheaveblocks are connected by a hydraulic cylinder and the oil of the hydraulic cylinder is connected to a gas volume under pressure. When the wire rope is connected to a riser, the wire rope is kept under a certain stress, so that the riser does not buckle. If the ship moves up and down, the tension in the wire rope is changed a bit (depending on the spring characteristic).