Description
Expansion joints are components used in pipeline, plant, and device construction. They are designed to withstand the same stresses as plant components and pipelines; additionally they must absorb added stresses, movements, or vibrations in axial or lateral direction. The main area of application for fabric expansion joints are plants conveying gaseous media. Precise technical installation data from the user are essential for optimised expansion joint designs to ensure a perfect fit for the relevant usage conditions in industrial plant construction.
Power plants, waste incineration plants, dust removal and filter systems, cement industry, steel industry, drying technology, chemical industry, conveyor technology, fan construction, ventilation technology, marine engineering, etc.
The multitude of possible material combinations allows the development of optimised solutions, which are generally influenced by prevalent mechanical, chemical, and thermal conditions. The structure of the expansion joint is generally based on the following material groups:
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CENTRE PART
|
AXIAL –
|
LATERAL –
|
|---|---|---|
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Straight
|
0.25 x AR
|
0.1 x AR
|
|
Concave
|
0.3 x AR
|
0.15 x AR
|
|
0.25 x AR
|
0.3 x AR
|
Suitable for round or oval crosssections. Mounting strips must be used for rectangular crosssections, and the duct walls must be drilled. For a vacuum system it is important to note that the expansion joint bellows will pull inward and constrict the flow diameter.
In these cases, support rings must be installed. Max. ope rating temperatures must not exceed 350 °C, as the fixing point will take on the temperature of the medium. The attachment of the joint is implemented using multipart hose clamps for sizes between Ø 700 mm and 800 mm.
For larger diameters, flange connections are recommended due to their higher sealing capacity.
This installation model covers all crosssection shapes and sizes. Rectangular connection points will require adequate hose diameters, and a drilling of the duct is not required. Due to the good temperature reduction properties in the attachment area, an implementation without preinsulation will be suitable for temperatures between 400 and 500 °C, and with preinsulation for temperatures between 600 and 700 °C. With relevant structural measures in place, i.e. inner brickwork lining, temperatures up to 1000 °C will be manageable.
Suitable for use for large dimensions or preexisting pipeline flanges, higher pressures, and high technical tightness requirements. Due to the inferior heat radiation in the attachment area, operating temperatures should not surpass 450 to 500 °C. With the use of larger flanges, the expansion joint can be placed further outward [away from the flow of the medium], and additionally protected by another insulation or retrofitted insulation. This will allow operating temperatures between 600 and 650 °C.
