Hyspan - Model Series 2500 - Laminated Bellows Expansion Joints
Series 2500 Laminated Bellows Expansion Joints are designed specifically for low pressure applications such as engine exhaust systems, fan connectors, ventilation ducting and air handling systems. The laminated bellows construction permits axial, lateral and angular movements without exerting high spring forces on the system, and the internal damping provided by the laminations limits resonate vibration. Series 2500 Laminated Bellows Expansion Joints are ideal for direct installation on engine exhaust manifolds, turbochargers and fan inlet and exhaust connections. Hyspan Series 2500 Round Expansion Joints are similar designs with single ply bellows that less suitable for vibration applications but ideal for use throughout the ducting and piping. Sizes range from 6' through 48' diameter.
Joints are designed for a maximum pressure (including test pressure) of 15 psig and a full vacuum. They are intended for applications such as engine exhaust, fan connections, vents and other very low pressure applications. The design temperature varies with the construction. The materials of construction for standard assemblies are: type 304 stainless steel bellows, van stone ends and flow liners; ASTM A-36 carbon steel plate flanges and angle flanges, and ASTM A-53 standard weight carbon steel pipe weld ends. Optional materials are available including the substitution of stainless steel for flanges and pipe. Recommended design temperatures are 775ºF for Types 2509 & 2511 with carbon steel fittings, 1100ºF for Type 2510 with carbon steel backup flanges and 1250ºF for allconfigurations if the component parts are stainless steel.
Tie rods are available as an option on Series 2500 Laminated Bellows Expansion Joints. They react the pressure thrust in piping and ducting that is not anchored such as the lateral offset application illustrated above. They may also function as Limit Rods. Limit rods do not react the pressure thrust in service but they are designed to react the pressure thrust in the event of an anchor failure. Their main function is to limit the axial extension and compression of the bellows to the rated values. Hyspan normally refers to both tie rods and limit rods as Tie Rods but the factory settings are important - factory settings as Tie Rods do not permit axial extension but limits compression to the rated value of the bellows. Factory settings as Limit Rods will permit axial extension and compression in accordance with the rated travel specified in the Design Data.
Flow liners or internal sleeves are optional features that are available for all configurations. Liners provide a means of isolating the bellows element from direct contact with the flow and as a result eliminating flow induced vibration, minimizing pressure loss and creating dead air space between the bellows that insulates the bellows. Hyspan installed flow liners follow the recommendations outlined in the Standards of the Expansion Joint Manufacturers Association (EJMA) summarized as follows.
Flow liners are recommended for:
- Gas applications exceeding 4 ft./sec./inch of diameter up to 6' NPS
- Gas applications exceeding 25 ft./sec. over 6' NPS.
- Liquid applications exceeding 2 ft./sec./inch of diameter up to 6' NPS.
- Liquid applications exceeding 10 ft./sec. over 6' NPS.
- All applications when flow turbulence is generated within 10 diameters from the expansion joint.
The lateral offset installation illustrated is a typical application of a Series 2500 Laminated Bellows Expansion Joint installed on an engine exhaust, fan intake or discharge. The high flexibility and internal damping provided by the laminated construction permits absorption of lateral movement from thermal expansion or mechanical motion. Refer to Column 5 of the Design Data for the maximum lateral off-set of each configuration. For applications of this type it is good practice to add Tie Rods to the expansion joint - see Tie Rods below.
Laminated Bellows Expansion Joints can also be installed in axial applications as shown in the axial travel illustration. The maximum Axial Compression and Axial Extension for each configuration is given in Columns 3 & 4 of the Design Data. Most Series 2500 applications do not require the amount of rated axial extension. For these applications the expansion joint can be ordered preset if additional travel is needed. As an example a 3' joint (-040-5) rated for 5' compression factory cold sprung 1' (extended 1') can be rated for 5' compression. The allowable axial extension will be reduced from 2.5' to 1.5'.