XLG®MD Regenerative Multitube heat exchangers are manufactured entirely from stainless steel and consist of a bundle of corrugated tubes mounted within a corrugated outer tube (which forms the outer shell).
The sterile fluid flows through the interior of the tubes forming the tube bundle and the raw (not-sterile) fluid outside the inner tubes, through the shell.
All product wetted surfaces, including the welds, have a surface roughness Ra < 0.8 µm and are therefore able to process food products under the normal hygiene regulations. Such processes include pasteurisation, high temperature sterilisation, thermal treatment for aseptic packaging etc.
Both fluids (sterile and not-sterile) are completely isolated from each other, heat transfer taking place across the inner tube walls. Leakage of the service fluid to atmosphere is prevented by a pair of elastomeric O ring seals at each end of the tube. If hygiene and process conditions require it steam packing can be provided between the O ring seals at both ends of the units
One tubeplate is fixed to the outer tube assembly and the other is free to expand and contract with the changes in temperature occurring in service thus avoiding the potentially damaging stresses that occur in other types of fully welded heat exchangers that use expansion bellows to absorb the differential expansion between the shell and the inner tubes.
Connections are DIN/ISO/ASME standard ferrules and clamps or DIN food standard screwed compression fittings.
All of our units are designed and manufactured according to the CE marking regulations contained in the European Pressure Directive (97/23/EC) and are CE marked when we are permitted to do so. Also our units are approved by the 3-A Organisation in the United States.
Materials of construction
All product wetted components (interior tube and bends etc.) are manufactured from AISI 316L stainless steel but for more aggressive fluids a range of Duplex stainless steels are also available.
Areas not in contact with the working fluids are normally constructed from AISI 304 stainless steel.
EPDM and silicone rubber is used for the O ring seals and connection gaskets or seals but a wide range of alternative elastomers are available when specific applications require them.
Alternative materials can be offered for all wetted components on application.
To allow a rapid and flexible installation and easy inspection of the units the XLG®MD Regenerators use DIN/ISO/ASME standard ferrule/clamp connections. If the matching ferrules, clamps gaskets are required by the client for installation purposes these can be supplied on request to allow connection to the clients’ pipework system.
The standard design conditions for the XLG®MD Regenerative Multitube heat exchangers are the following:
Minimum and maximum allowable working temperatures: -40°C / +180°C
Minimum and maximum allowable working pressures: 10 Bar(g)/Full vacuum
Higher pressures and temperatures are possible on request.
XLG®MD Regenerator heat exchangers can be delivered in various lengths, the standard dimensions being approximately 1500 mm, 2000 mm, 3000 mm and 6000 mm.
Shell diameters can reach from Ø 88.9 mm up to 204 mm. The tube thickness used will depend on the design conditions for each application.
The diameters of the interior tubes and their wall thickness will be chosen to meet the requirements of each application.