RUBBER EXPANSION JOINTS FOR PIPING SYSTEMS

Careful selection of the expansion joint design and material for a given application, as well as properly engineered installation are important factors in determining performance. These factors should be fully evaluated by each person selecting and applying expansion joints for any application.

*Rubber expansion joints have been specified and used for many years by consulting engineers, mechanical contractors, pressure vessel designers, plant engineers and turnkey construction firms. They are installed to accommodate movement in piping runs, protect piping from expansion and contraction and insure efficient and economical on-stream operations.

Rubber expansion joints provide time-tested ways to accommodate pressure loads, relieve movement stresses, reduce noise, isolate vibration, compensate for misalignment after plants go on stream and prolong the life of motive equipment. Rubber expansion joints, designed by engineers and fabricated by skilled craftsmen, are used in all systems conveying fluids under pressure and/or vacuum at various temperatures:

• Air conditioning, heating and ventilating systems in commercial and institutional buildings, schools, apartments, stores, hospitals, motels, hotels and aboard ships.
• Central and ancillary power-generating stations in communities, factories, buildings
and aboard ships.
• Sewage disposal and water-treatment plants.
• Process piping in paper and pulp, chemical, primary metal and petroleum refining plants.

The Advantages of Rubber Expansion Joints and Flexible Connectors

The Rubber expansion joint industry has allied itself with designers, architects, contractors and erectors in designing and fabricating joints under rigid standards to meet present-day operating conditions. UIP has kept abreast of the technological advances in rubber compounding and synthetic fabrics to provide rubber expansion joints having advantages not available in other materials.

• Economy of minimal face-to-face dimensions
• Lightweight construction requires no special
handling equipment
• Insulates against the transfer of noise and vibration
• Compensates for misalignment
• No electrolysis
• Greater recovery from movement
• Ease of installation
• Small space requirements
• Low movement forces required
• Reduced fatigue factor
• Reduced heat loss
• Corrosion and erosion resistant
• No gaskets required

Why Use Rubber Expansion or Vibration Joints?

Three Basic Reasons for Their Use:

1. To Prevent Stresses Due to Expansion and Contraction
2. To Insulate Against the Transfer of Noise and Vibration
3. To Compensate for Misalignment

Rubber or non-metallic expansion joints are flexible connectors fabricated of natural or synthetic elastomers, fluoroplastics and fabrics, and when necessary, metallic reinforcements provide stress relief in piping systems due to thermal and mechanical vibration and/or movements.

UIP Rubber Expansion Joints provide relief from stresses caused by thermal expansion and contraction in pipelines. Movement is always experienced in piping systems due to varying ambient temperatures, differences in temperature of materials handled, and differences in composition. Expansion joints absorb this movement and eliminate the danger
of buckling or pulling apart with the high replacement costs that would result.

Pumps, compressors and other pulsating equipment generate noise and vibration. The transmission of noise and vibration tends to reduce the efficiency of adjacent equipment and impairs working conditions in offices and plants. Expansion joints serve as reliable insulation against such vibration and noise.

Settlement, load stresses and normal wear of components will frequently cause piping and mechanical equipment to become misaligned.
Expansion joints can resolve these problems within their design limits. Special designed expansion joints are available for specific conditions and misalignment.

Engineers can solve anticipated problems of vibration, noise, shock, corrosion, abrasion, stresses and space by incorporating rubber expansion joints into designed piping systems.

Functions:

Reduce Vibration
Rubber expansion joints isolate or reduce vibration caused by equipment. Some equipment requires more vibration control than others. Reciprocating pumps and compressors, for example, generate greater unbalanced forces than centrifugal equipment. However, rubber pipe and expansion joints dampen undesirable disturbances including harmonic overtones and vibrations caused by centrifugal pump and fan blade frequency. This is based on actual tests conducted by nationally recognized independent testing laboratory. Rubber expansion joints reduce transmission of vibration and protect equipment from the adverse effects of vibration.

Dampen Sound Transmission
Subsequent to going on stream, normal wear, corrosion, abrasion and erosion eventually bring about imbalance in motive equipment, generating undesirable noises transmitted to occupied areas. Rubber expansion joints
tend to dampen transmission of sound because of the steel-rubber interface of joints and mating flanges. Thick-wall rubber expansion joints, compared with their metallic counterparts, reduce considerably the transmission of sound.

Compensate Lateral, Torsional and Angular Movements
Pumps, compressors, fans, piping and related equipment move out of alignment due to wear, load stresses, relaxation and settling of supporting foundations. Rubber expansion joints compensate for lateral, torsional and
angular movements, preventing damage and undue downtime of plant operations.

Compensate Axial Movements
Expansion and contraction movements due to thermal changes or hydraulic surge effects are compensated for with strategically located rubber expansion joints. They act as helix springs, compensating for axial movements.