Rubber Expansion Joint
RADCOFLEX: Rubber Expansion Joint
Radcoflex products are used extensively throughout many industries for a wide variety of applications including the conveying of materials and gases, mechanical protection, pipeline movement control and vibration
Rubber Expansion Joint
Radcoflex flexible rubber expansion joints materials meet or exceed the requirements of the Rubber Expansion Joint Division, Fluid Sealing Association (FSA) for Standard Class I and II, and for some applications Class III.
Flexible rubber joints are generally manufactured in three types – the moulded spherical type, the conventional hand built high spool arch type and the wide arch type. The three types all have their advantages.Radcoflex can supply all three.
Moulded spherical type
These are the economical rubber joints being mass produced in single and double sphere styles. They are manufactured by the high pressure moulding of heat resisting rubber with high tensile fabric reinforcement.This produces a joint of lighter construction than with the hand-built joints resulting in a more flexible joint with the lower spring forces thereby reducing stress on the system.The spherical shape is inherently stronger than the spool arch type with internal pressure forces being distributed over a larger surface area.Styles FSF, FTF and UTU described in these data sheets are moulded spherical type rubber joints. These are fitted with floating metal end connections for easy installation.
High spool arch type
These are hand built to the specific requirements of the installation thereby ensuring a long working life. The joints have moulded integral flanges which provide a tight seal to the mating surface.High Spool Arch joints can be supplied with a filled arch to improve flow rates, reduce flow turbulence and limit the collection of solids in the arch.
Wide arch types
The wide arch type combines many of the features of both the moulded spherical and hand built spool types.The type incorporates a spherical long flowing arch with moulded integral flanges. The long flowing arch provides improved movement capabilities over the spool type and reduced turbulence in the medium conveyed. The integral flanges provide a tight seal to the mating surface.
Typical applications
Flexible rubber joints provide a cost effective solution for demanding industrial applications conveying water, air, mild corrosive fluids and odours, with the added advantage of reducing fluid-borne noises.
The rubber joints are primarily used to:
– absorb or isolate vibration
– compensate for system misalignments
– protect system against startup and pressure surges
– absorb water hammer and vibration noises
– absorb pipework stresses.
They have a number of applications in the air conditioning, heating and ventilating, power generation, water treatment, pulp and paper, chemical, pollution control, marine, mining and industrial process piping industries.Rubber expansion joints compliment the Radcoflex range of metal bellows expansion joints offering a low cost alternative for certain simple movement, low temperature and mildly corrosive applications. Rubber joints can also provide a ‘quieter’ alternative to metal joints as system generated sounds lose their energy as they travel axially through the rubber section.
Technical Characteristic
Technical Aspect
Types of movement
Flexible rubber joints are installed in a piping system to absorb movements in three directions:
– Axial – the movement of elongation and compression along the centre line
– Lateral – offset movement from the centre line
– Angular – offset bending about the centre line
Style FSF, FTF and UTU joints are not capable of absorbing more than one movement at a time (i.e. non-concurrent), nor absorbing torsional (i.e twisting) movement. Styles WA and HS can absorb different movements concurrently and can accept torsional movement of 10-20when the joint is at its free or neutral length, however every effort should be made to design such movement out of the system.
Pressure and Temperature
The pressures listed in the product data sheets are the nominal operating (working) pressures at a temperature of 80ºC (170ºF) for correctly anchored and guided expansion joints.The test pressure is 1.5 times the positive nominal operating pressure held for 10 minutes.The burst pressure is approximately 4 times the operating pressure on diameters up to 300mm, and approximately 3 times for larger diameters.The pressure rating of the joint is reduced as the temperature rises above 800C. Below is the correction factor to be applied.
Flexible rubber expansion joints should be installed between two fixed anchor points in a piping system – see ‘installation instructions’ data sheet.Anchored Systems – control rods are not required to be fitted to the joint piping systems that are correctly anchored and where the joint will be operating within an acceptable movement range for that joint – see the expansion joint specification tables in the data sheets
Unanchored systems – control rods are recommended for all applications where the piping system is not correctly anchored. In particular, control rods must be used when the pressure exceeds:
