Why are expansion joints and bellows needed in piping systems?

Posted by Dutco Tennant LLC on December 2nd, 2021

Do you want to reduce mechanical noise and vibration in your piping system? Looking for a solution to relieve stress and strain in your piping system? Then, without further ado, buy the expansion joints and bellows.

Available in a wide variety of designs, while some of the expansion joints are standard, some can be custom designed according to the requirements of the client. These expansion joints are used in the piping system to help absorb the terminal movement or thermal expansion and also aid in reducing the pipe loads at connections to sensitive equipment like steam turbines and pumps.

Components of an expansion joint

  • Dowel bar
  • Bond breaker tape
  • Joint filler
  • Joint sealant
  • PVC dowel sleeve
  • Cradle bent
  • Bellow
  • Flanges

The expansion joints allow the pipes to move in three ways:

  • Lateral offset
  • Axial compression or extension
  • Angular deflection

Materials used to make expansion joints

Mostly, the expansion joints come in three materials – rubber, metal and braided. There’s also a Teflon expansion joint, which is widely used in the chemical processing industry. Let’s take a look in detail how these materials help in various applications  

Rubber: A good material for thermal expansion, rubber absorbs shock waves and vibrations really well. So if you are looking for expansion joints to reduce the transmission of vibration and noise from other devices, then go for this type of expansion joint. The rubber expansion joints also help to reduce the shock that is caused by pressure surges, seismic events and water hammer.

The rubber joints can help in solving pressure pulsation and movement in the piping system, corrosion, abrasion, noise, shock and vibration. These joints also help in reducing the load stress and equipment movement.

Braided: If you are looking for an expansion joint which works well in high temperature and high pressure applications, then braids are your best choice. The pipes which require misalignments need braids. Braids are often used in equipment and pumps to get rid of thrust load due to the thermal expansion. Braids also help in the absorption of vibration rather well.

Metal: Do you have a problem in the piping system related to thermal expansion? Then, we suggest you buy the metal expansion joints. When the temperature of the pipe increases, the metal expansion joint reduces thus taking stress off the pipes and the anchors. An ideal example of a metal expansion joint is how to handle expanding hot pipes.

Teflon expansion joints

These expansion joints are mostly used in the chemical processing industry and in the piping system where acids or highly corrosive chemicals are used. Thanks to the unmatched reliability, corrosion proof ability of these joints, they are also used in the commercial heating and air conditioning systems as pump connectors. These expansion joints are also used to compensate for angular deflection or vibration in the piping application.

Bellows

It is without saying that bellows are the most important element in the piping expansion joint.  The most flexible part of the expansion joint, which is designed to absorb axial movement, is known as the bellow. They are of two types of bellows – formed bellows and fabricated bellows. While the formed bellows comprise only longitudinal welds, the fabricated ones have a series of thin gauge discs welded together.

Why are expansion joints used in the piping system?

In the piping applications, the use of expansion joints is considered of paramount importance. The expansion joints are mostly used in industries where thermal expansion takes place in the pipe systems. If there are expansion joints in the piping system, then it will help in the reduction of stress in the application, which is caused by thermal expansion. This helps in the reduction of pipe loads at connections to sensitive equipment like steam turbines and pumps. When expansion joints are used in the piping system, the longevity of the system increases. The expansion joints also reduce the cost of additional maintenance and repair. In fact, if you remove the expansion joints from the piping systems, then high tension would be created due to the thermal expansion. This can lead to huge pressure thus resulting in development of cracks in welds and even lead to bending of the pipes.

In fact, the pipe designers and engineers prefer the use of expansion joints in the piping applications. The expansion joints, which are available in various shapes and sizes, help to reduce cost by eliminating the complexity of guides and fix points. The expansion joints also decrease the overall space needed for the piping system. And why won’t the engineers and pipe designers root for expansion joints? These joints are more efficient than the alternatives like pipe looks and pipe bends. Thanks to the great capability to fit into the space, the expansion joints are cost effective and perform much better when it comes to absorbing large movement.

Use of expansion joints

From chemical industries, steel plants to nuclear power plants, expansion joints are used in different industries. Let’s take a look at some of the most common industries where expansion joints are used.

  • Steel plants
  • Widely used in the energy sector such as power plants and nuclear power plants
  • Exhaust systems
  • Pulp industry
  • Engines
  • Paper industry
  • Chemical industry
  • Petrochemical industry, which includes pumping stations
  • Boilers
  • Pumps
  • Turbines
  • LPG Tankers

In conclusion, expansion joints are mostly used in cement, construction, petroleum, metallurgy, and other industries in recent years. The use of expansion joints and bellows in the piping systems cannot be ruled out. Made of covers, tie rods and flow liners, the metal bellows behave like springs and are restricted to contain the pressure of the liquid that flows through the expansion joint. Also if the expansion joints are not present in the piping applications, then thermal expansion would be caused which might lead to bending of the pipes. 

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Dutco Tennant LLC

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Dutco Tennant LLC
Joined: February 11th, 2019
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