Rubber expansion joints

Rubber expansion joints – general information

Rubber compensators are widely applied in a variety of industrial pipelines, in power plants, in heating networks (heat transfer stations) and sanitary installations (sewage treatment plants and pumping stations, water treatment stations and machines). Basically, they are mounted near components that produce vibrations (pumps, engines, turbines, compressors etc.). They absorb different movements: axial, lateral and angular that result from thermal expansion of the pipelines or misalignment. They dampen vibration and noise and absorb the energy of pressure variations.

Working pressure up to 25 bar, working temperature from -40°C to 150°C depending on material and medium. Nominal diameter range from DN15 to DN1000. Most of compensators is fitted with swivel flanges put on the fold of the bellow. Some compensators are fitted with fixed flanges, threaded connections or other connections mounted with worm drive clamps. Flange material: zinc-plated steel, stainless steel and acid-resistant steel, aluminium. Flanges PN 10/16, PN25, ANSI 150 lb. and other. Accessories: inner PTFE liner, tie rods, vacuum supporting ring or spring, thermal protective cover.

Rubber bellow material vs. medium

Expansion joints are constructed of a rubber bellow reinforced with synthetic or steel cord and connectors to mount them into a pipeline (usually steel flanges). The expansion joints are classified by bellow material and application into several types:

• EPDM, CR, IIR rubber expansion joints designed for cold and hot water (industrial water, seawater, potable water), acids, bases and other slightly aggressive chemicals. They are not suitable for oils, fats and hydrocarbons;
• EPDM rubber anti-vibration hump connectors with threaded pipe unions for water systems;
• NBR or HNBR rubber expansion joints designed for oils, substances containing fat, petroleum products, some hydrocarbons, natural gas;
      white NBR rubber expansion joints designed for food substances, containing fats and oils, alcohol;
      conductive NBR rubber expansion joints for LPG (propane-butane);
• CSM rubber expansion joints, for chemicals and natural gas;
• FPM (Viton) fluorocarbon rubber expansion joints for chemicals and hot petroleum products;
• NR/BR rubber expansion joints (natural rubber/polybutadiene) for highly abrasive substances in the form of water suspension, slurry, sludge as well as dust and powder. They are not suitable for oils, fats and hydrocarbons;