SINGLE BELLOWS EXPANSION JOINTS

Macroflex Single Expansion Joints are designed to absorb axial, lateral, and angular movements in piping systems. Constructed by attaching fittings to a single stainless-steel bellows, they are commonly used for axial compression and extension. A single metal expansion joint is the most economical solution to smaller movements. The bellows will deflect in any direction or any single plane.

These metal expansion joints do not restrain the internal pressure thrust. The piping designer must provide the system with separate anchoring and guiding to resist the pressure thrust force of the expansion joint.

Style “W” Macroflex Single Bellows Expansion joint complete with weld ends.

Style “FP” Macroflex Single Bellows Expansion Joint complete with flat face plate flanges.

Also available (not shown), Style “FS” Single Bellows Expansion Joint with raised-face flanges.

Style “FLLP” Macroflex Single Bellows Expansion Joint complete with floating flanges.

Style “V” Macroflex Single Bellows Expansion Joint complete with grooved ends.

Macroflex Single Expansion Joint is an assembled product of various components like bellows, flanges, weld ends, special-machined flanges or weld ends and offers optional accessories, like liners, tie rods, limit rods, control rods, shrouds (covers), collars, multi-ply designs and testable bellows.

These joints are suitable for a wide range of applications, accommodating diameters from 2″ to 140″, temperatures from -400ºF to 1500ºF, and pressures from full vacuum to 750 Psig. (depending on the diameter).

We can supply bellows both ferrous: T304 SS, T304L SS, T321 SS, T347 SS, T316 SS, 316L and non-ferrous: Inconel 600, Inconel 625, Incoloy 800, Incoloy 825, Hastelloy C-276, Nickel 200, Monel 400 and Titanium materials.

Macroflex expansion joints meet the Standards of the Expansion Joint Manufacturers Association (EJMA).

Standard Single Expansion Joints Drawings available in DOWNLOADS section.
Engineering Specifications available in DOWNLOADS section.
Line Guiding Principles available in DOWNLOADS section.
Installation Instructions available in DOWNLOADS section.

INSTALLATION EXAMPLES

Figure [A1] typifies good practice in the use of a Single Expansion Joint to absorb axial pipe line expansion. Note the use of one Expansion Joint between two main anchors (MA), the nearness of the Expansion Joint to an anchor, the closeness (4D= 4 x pipe diameter) of the first alignment guide (G1), the spacing between the first alignment guide (14D = 14 pipe diameters) and the second alignment guide (G2), and the spacing of intermediate guides (G) along the balance of the line.

Figure [A2] typifies good practice in the use of a Double Expansion Joint with integral anchor or two Single Expansion Joints placed adjacent to each other, to absorb axial pipe line expansion. Note the addition of the intermediate anchor (IA) which in conjunction with the two main anchors, divides the pipe line into individual expanding sections, so that there is only one Expansion Joint between any two anchors.

Note also the closeness of the first alignment guide (G1) to each Expansion Joint (4D = 4 x pipe diameter), the spacing between the first alignment guide (14D = 14 x pipe diameter) and the second alignment guide (G2), and the spacing of intermediate guides (G) along the balance of each pipe section.

Figure [A3] typifies good practice in the use of Expansion Joints to absorb axial pipe line expansion in a pipe line with a branch connection. The anchor at the junction, which in this case is a tee, is a main anchor (MA) designed to absorb the thrust from the Expansion Joint in the branch line.

Note the proximity of each Expansion Joint to an anchor, the closeness (4D= 4 x pipe diameter) of each first alignment guide (G1), the spacing between the first alignment guide (14D= 14 x pipe diameter) and the second alignment guide (G2), and the spacing of intermediate guides (G) along the balance of each pipe section.

Figure [A4] typifies good practice in the use of Expansion Joints to absorb axial pipe line expansion in a pipe line containing a reducer. The anchor at the reducer is a main anchor (MA) designed to absorb the difference in the thrusts of the Expansion Joints on each side of the reducer.

Note the proximity of each Expansion Joint to an anchor, the closeness (4D = 4 x pipe diameter) of the first alignment guide (G1), the spacing between the first alignment guide (14D = 14 x pipe diameter) and the second alignment guide (G2) and the spacing of intermediate guides (G) along the balance of each pipe section.

Figure [A5] shows the application of a single Expansion Joints to a line containing an offset, absorbing axial expansion. Note the proximity of the Expansion Joint to the main anchor (MA), the closeness of the first alignment guide (G1), the spacing between the first alignment guide and the second alignment guide (G2) and the spacing of intermediate guides (G) along the balance of the line. Guides should be installed near both ends of the offset leg to minimize the effect of the bending moment on the systems.

Figure AL1 shows a typical application of a single Expansion Joint absorbing combined axial movement and lateral deflection. The Expansion Joint is located at one end of the long piping leg with a main anchor at the far end of the line and a directional anchor close to the expansion joint. The directional anchor permits thermal expansion of the short piping leg to act upon the Expansion Joint as lateral deflection.

AL2 shows an alternate arrangement in which the Expansion Joint is installed in the short piping leg and the principal expansion is absorbed as lateral deflection. The longer piping leg is free of compressive pressure and pressure thrust of the Expansion Joint and requires only an intermediate anchor and directional guiding. The functions of the directional anchor and the pipe guide may be combined in a single device.

Figure AL3 and AL4 (below) represent modifications of figure AL2 in which the directional anchor closest to the expansion joint is replaced by tie rods which contain the pressure thrust of the Expansion Joint. Where the piping configuration permits, the use of tie rods adjusted to prevent axial movement frequently simplifies and reduces the cost of installation. Because of these rods, the Expansion Joint is not capable of absorbing any axial movement other than its own thermal expansion.

The thermal expansion of the piping in the shorter leg is, as a result, imposed as deflection on the longer piping leg. Where the longer piping leg is not sufficiently flexible and where the dimension of the shorter leg is suitable, tie rods may be installed spanning the entire short leg so that no deflection is imposed on the longer run from this source.

Where appreciable amounts of lateral deflection are imposed upon the Expansion Joint, some shortening of the Expansion joint results from the displacement of the tie rods as shown in Figure AL3 (hot position). Care should be taken to ensure that sufficient flexibility exists to absorb this deflection of the and that adequate clearances are provided in the guide to permit deflection on the piping. The amount of this deflection can be minimized by cold springing the Expansion Joint in the lateral direction as shown in Figure AL4.