Products

Rubber expansion joints

Thermal growth, equipment movement, vibration or pressure pulsation may generate movement in a piping system. When this movement is not absorbed by the piping system itself, an expansion joint is the perfect solution.

A Rubber Expansion Joint is flexible connector fabricated of natural or synthetic elastomers, fluoroplastics and fabrics and, if necessary, metallic reinforcements used to absorb movements in a piping system while containing pressure and a medium running through it.

Features

Absorb Axial movements (extension and compression).
Axial movement is the change in dimensional length of the bellows from its free length in a direction parallel to its longitudinal axis.

Absorb Lateral movements.
Lateral movement is the relative displacement of one end of the bellows to the other end in a direction perpendicular to its longitudinal axis.

Absorb Angular and Torsional Movements.
Angular movement is the rotational displacement of the longitudinal axis of the bellows toward a point of rotation. Torsion refers to twisting one end of the bellows with respect to the other end, about the bellows centerline.

Reduce Vibration.
Rubber expansion joints isolate or reduce vibration caused by equipment. The transmission of vibration is reduced and they protect equipment from these adverse effects.

Dampen Sound Transmission.
Rubber expansion joints tend to dampen transmission of sound because of the steel-rubber interface of joints and mating flanges

Advantages

Reduced fatigue factor
Given the inherent characteristics of natural and synthetic elastomers, they are not subject to fatigue breakdown or embrittlement and prevent any electrolytic action because of the steel-rubber interface of joints and mating flanges.

Extraordinary resistance to abrasion and corrosion
A wide variety of natural, synthetic and special purpose elastomers and fabrics are available to the industry. Materials are treated and combined to meet a wide range of practical pressure/temperature operating conditions, corrosive attack, abrasion and erosion. See table of materials.

Minimal face-to-face dimensions while absorbing large movements
With a minimal face to face length the Rubber Expansion Joints provide superior movement capability in axial compression, axial extension, and lateral deflection, as well as in the angular and torsional direction.

Low Spring Rates due to inherent flexibility of rubber
The inherent flexibility of rubber expansion joints permits almost unlimited flexing to recover from imposed movements, requiring relatively less force to move, thus preventing damage to motive equipment.

No gaskets required for installation
Elastomeric expansion joints are supplied with flanges of vulcanized rubber and fabric integrated with the tube, making the use of gaskets unnecessary in most of the applications. Check assembly instructions before installation.

Lightweight
Rubber Expansion joints are relatively light in weight, contributing to lower installation labour costs.

Reduced Heat Loss
Rubber expansion joints reduce heat loss, giving long maintenance-free service.

Rubber expansion joint example 1

Applications

  • Power generating stations
  • Oil & gas
  • Desalination
  • Cooling systems
  • Pumps
  • Chemical plants
  • Heating, ventilating and air conditioning
  • Shipbuilding
  • Off-shore applications
  • Water treatment plants
  • Sewage
  • Sanitary piping systems
  • Pulp and paper plants
  • Piping systems for chilled or hot water
  • Cooling systems power generation
  • Phosphate plants
  • Potable water
  • Food process

Construction details

MACOGA rubber expansion joints are designed following the guidelines of the FSA (Fluid Sealing Association) Non-Metallic Expansion Joints Technical Handbook, ASTM F1123 - 87 Standard Specification for Non-Metallic Expansion Joints and always complying with the European Pressure Equipment Directive 2014/68/UE for the specified operating conditions.

MACOGA Rubber Expansion Joints are manufactured considering:

  • Chemical resistance of internal layers.
  • Temperature resistance.
  • Movement absorption capabilities.
  • Pressure resistance.
  • Weather, ozone and UV-resistance of external layers

Rubber Expansion joints are fabricated with an elastomeric tube reinforced with multiple plies of fabrics covered with synthetic rubber. The inner tube is made of natural rubber, synthetic rubber or blend of synthetic rubber. The fabrics are Nylon®, Polyester, Aramid or Kevlar®. An additional reinforcement to the fabric may be provided in the body of the expansion joint and may be solid metal rings or wire embedded in the rubber.

Rubber expansion joint section showing internal fabrics

Materials

Rubber bellows
A rubber bellow is manufactured from independent rubber layers and reinforcements that are vulcanized together after being molded or formed.

With over 35 rubber elastomers available and the ability to further modify properties by compounding it can be challenging for non-specialists to select the most appropriate rubber polymer for their requirements. Our experts may assist our customers with material selection for a proper performance and to reduce the risk of failure.

Fabric reinforcements
Standard constructions normally utilize high quality synthetic fabric like Nylon®, Polyester, Aramid or Kevlar®. Fabric plies are impregnated with rubber or synthetic compounds to permit flexibility between the fabric plies.

Metal reinforcements
Wire or solid steel strings are imbedded in the carcass and are used as strengthening members of the joint.

Flanges
Carbon steel as standard. Also available in zinc plated or hot dip galvanized carbon steel, stainless steel, duplex, etc. Flanges drilled to EN, ANSI, JIS, AWWA standards or any specific dimension.

Colour label
Abbreviation
Name
Temp. range ºC
Properties
Application
RED
EPDM
Ethylene Propylene Diene Monomer
-35 to +100
Weather-resistant, good gas tightness, resistant to attack by oxygen, U.V., ozone and extreme weather environments.
Hot water, cooling water with salt solutions, chlorine solutions, esters and ketones
DOUBLE RED
EPDM HT
Ethylene Propylene Diene Monomer HT
-35 to +130
Special EPDM rubber compound suitable for high temperature up to 140 °C applications without hardening. Weather-resistant, good gas tightness, resistant to attack by oxygen, U.V., ozone and extreme weather environments.
High temperature applications up to 140 °C. Hot water, cooling water with salt solutions, chlorine solutions, ester, ketones, compressed air (oil free) and chemicals except for hydrocarbons.
RED+WHITE
EPDM DW
Ethylene Propylene Diene Monomer DW
-35 to +90
FDA approved.
Drinking water.
YELLOW
NBR NITRILE
Nitrile Butadiene Rubber
-40 to +90
Good general resistance to oils and hydrocarbons. Good mechanical properties especially tensile strength, flexibility, compression set and impermeability to gases. Moderate ageing properties. Good abrasion resistance.
Oil and fuel, also suitable for gases, solvents and fats. Mineral oils, vegetal and animal oils, oils aerosols, butane or propane gas.
Not suitable for steam and hot water.
DOUBLE YELLOW
NBR HT
Nitrile Butadiene Rubber HP
-40 to +140
Good general resistance to oils and hydrocarbons. Good mechanical properties especially tensile strength, flexibility, compression set and impermeability to gases. Moderate ageing properties. Good abrasion resistance.
High temperature applications up to 140 °C. Oil and fuel, also suitable for gases, solvents and fats. Mineral oils, vegetal and animal oils, oils aerosols, butane or propane gas.
Not suitable for steam and hot water.
WHITE
NBR-W
White Nitrile Butadiene Rubber
-20 to +90
FDA approved material and has good resistance to oils and greases.
Foodstuff, good for pulps, flours, juices and wines. Food and beverages, including fats and oils.
GREEN
CSM HYPALON
Chloro-sulphonated polyethylene synthetic rubber
-20 to +90
Excellent resistance to oxidation. Outstanding resistance to atmospheric conditions and in particular strong sunlight and ozone.
CSM compounds resist fire and are self-extinguishing.
Strong and/or concentrated acids and bases, freons, hydroxides, ozone, compressed air that bears oil aerosols, etc.
BLUE
SBR
Styrenebutadiene rubber
-25 to +85
Good resistance to abrasion. Excellent mechanical properties. Only moderate resistance to tearing, ozone and general weathering.
Wearing material such as sludge suspended stones, calcium, etC.
BLACK
CR NEOPRENE
Polychloroprene
-25 to +90
The best multi-function rubber. Good resistance to temperature changes, ozone action and adverse weather conditions. Good mechanical and abrasion properties.
Resistance to chemicals; resistant to inorganic chemical products except oxidizing acids and halogens. Moderate resistance to aliphatic hydrocarbons.
Water, warm water, seawater, air and weak acids. Suitable for some small groups of acids as well as compressed air and lightly oil-related media.
RED+BLUE
IIR BUTYL
Isobutylene isoprene rubber
-30 to +120
Low gas permeability. Good ozone and weather resistance. Resistant to oxidizing agents, vegetable and animal fats and polar solvents. Poor wear resistance. Not resistant to hydrocarbon solvent and oil.
Animal and veg. oils, fats, greases, air, gas, water, many oxidizing chemicals and ozone.
BROWN
NRL NATURAL RUBBER
Natural rubber
-25 to +80
Excellent mechanical properties. It has excellent tensile, elongation, tear resistance and resilience. Excellent abrasion resistance and excellent low temperature flexibility. Poor resistance to ozone, oxygen, sunlight and heat. It has poor resistance to solvents and petroleum products.
Seawater, sewage, resist weak acids and alkalis. Up to 65 °C it has a good resistance against: hydrochloric acid in any concentration, sulfuric acid up to 50% concentration, sodium hydroxide, diluted and concentrated potassium hydroxide.
GRAY
BR POLYBUTADIENE
Polybutadiene
-40 to +80
Excellent mechanical properties. Excellent abrasion resistance and excellent low temperature flexibility. Poor resistance to attack by petroleum oils, poor ozone, UV resistance.
Up to 65 °C it has a good resistance against: hydrochloric acid in any concentration, sulfuric acid up to 50% concentration, sodium hydroxide, diluted and concentrated potassium hydroxide.
PURPLE
VITON FKM (ASTM) FPM (DIN/ISO)
Fluorine-polymer
-20 to +150
Good flame resistance, resistance to oxygen, ozone and natural weathering. Poor performance against ethers, ketones, and bases.
High concentrated chemicals up to 150 °C. Hydrocarbons, aliphatic, aromatic and chlorinated chemicals. Good resistance to acids and alkali’s including oxidants. Good resistance to chemicals, oils, combustibles and solvents.

Temperatures listed above are the typical maximum degree ratings for continuous use.

Fabric reinforcements:
Nylon ©, Polyester, Aramid or Kevlar ©

Metal reinforcements:
Wire or solid steel strings are imbedded in the carcass and are used as strengthening members of the Expansion Joint.

Analysis and design practices

Our analysis and design practices include:

  • Finite Element Analysis (FEA)
  • Pipe Stress Analysis
  • CAD
  • 3D Modelling

We use the most sophisticated analysis and calculation software to design pipe systems and select the most appropriate Expansion Joints providing a complete pipe stress analysis when required.

With our 3D mechanical CAD software our engineers design Expansion Joints to the same conditions that they’ll experience in the real world before they have been built. This is a design validation tool that helps our engineers to test the designs earlier in the design cycle and against real-world conditions. This lead us to improved design quality and manufacturing efficiency, while reducing time to market, costs and materials waste.