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The Function And Classification Of The Expansion Joint

Jan 07, 2018

The expansion joints can be called pipe expansion joints, expansion joints, compensators, and extender. Expansion joints are divided into: corrugated expansion joint, sleeve expansion joint, square natural compensation expansion joint and so on. The corrugated expansion joint is more commonly used, mainly for ensuring the safe operation of pipelines, and the expansion joint also has the following functions.

1. to compensate for the expansion deformation caused by the axial, transverse and angular direction of the pipe.

2. absorbs the vibration of the equipment to reduce the effect of the vibration of the equipment on the pipe.

The deformation of the pipeline 3., absorption of seismic subsidence.

Because the pipeline thermal expansion and contraction, so for the pipeline, will produce a wall stress and push pull; wall stress, effect of pipeline strength, force increases, fixed support pipeline will do great to bear the force generated by the expansion pipe; so the use of expansion joint compensation variable quantity way, in order to reduce the stress of pipe wall and thrust. Expansion joints (expansion joints) are mainly used to compensate for pipeline expansion and deformation due to temperature changes, and also for pipeline length compensation due to installation and adjustment. They are mainly divided into 3 structural forms: elbow expansion joint, bellows expansion joint and bushing expansion joint.

A bend type expansion joint that turns the tube into a U or other form and uses the elastic deformation capacity of the body to compensate for an expansion joint. Its advantages are good strength, long life, and can be produced on the spot. The disadvantage is that it takes up large space, consumes much steel and has great friction resistance. The expansion joint is widely used in various steam pipes and long pipelines.

A bellows expansion joint is a kind of expansion joint made of metal bellows. It can stretch along the axis and allow a small amount of bending. Axial bellows expansion joint of axial length compensation in the pipeline. In order to prevent exceeding the allowable amount of compensation, a protective pull rod or a protective ring is set at both ends of the bellows, and a guide bracket is set on the two ends of the pipe connected to the bellows. There are also corner and lateral expansion joints, which can be used to compensate the corner deformation and lateral deformation of the pipe. This kind of expansion joint has the advantages of saving space, saving materials, making it convenient for standardization and mass production, and the shortcoming is short life. Bellows expansion joints are generally used in pipes with low temperature and pressure and short length. With the improvement of the production technology of bellows, the application scope of this kind of expansion joint is expanding.

The casing expansion joint is composed of inner and outer casing capable of axial relative motion. Packing seal is used between inner and outer casing. In use, the two ends of the tube are kept moving on an axis. A guide bracket is installed at both ends of the expansion joint. Its advantages are small friction resistance to fluid flow and compact structure; the disadvantage is that the sealing property is poor and the thrust of the fixed support is large. Casing expansion joints are mainly used for water pipes and low pressure steam pipes.