| Piping systems are ubiquitous to heavy industrial | | | | Bellows Assembly with tie rods, increasing system |
| markets. If there is fluid or gas movement, be it in | | | | design flexibility. * Tied Universal Assemblies: like |
| the petrochemical, electric power supply, paper and | | | | Universal Assemblies, these limit lateral offset and |
| pulp or a variety of OEM industries, optimal operation | | | | angular movement by utilizing tie rods to absorb |
| and "up-time" require state-of-the art piping systems | | | | pressure thrust. * Hinged Bellows Assemblies: angular |
| to keep your plant competitive, or better, ahead of | | | | movement is limited to one plane. Two or three |
| the curve. You know your business, and you know | | | | Hinged Bellows Assemblies may be employed to |
| that in order to be profitable, your system must run | | | | handle large amounts of expansion in high pressure |
| at maximum efficiency. Metal Bellows Expansion | | | | piping situations. * Gimbal Bellows Assemblies: allow |
| Joints allow you to control fluid movement and | | | | angular movement in all planes, while absorbing |
| containment in your system under a wide variety of | | | | pressure thrust and twisting movement. When used |
| pressures, thermal expansion and contraction, | | | | in conjunction with a Single Hinged unit, these are |
| pulsations, vibration, equipment movement and | | | | particularly suited to maximize absorption in |
| convoluted routing requirements. | | | | multi-planer piping systems. |
| Typically, the key component of an expansion joint is | | | | While an in-depth discussion is beyond the scope of |
| the Metal Bellows element. Flexibility is paramount in | | | | this article, a variety of options and accessories are |
| containing the media and the pressure inherent in the | | | | available, and often necessary, to complete the |
| system. Metal Bellows Expansion Joints, thin-walled, | | | | installation of Metal Bellows Expansion Joint |
| corrugated membranes, provide this flexibility. | | | | Assemblies. Briefly, these include the following: * Ties |
| An excellent solution is the use of punch formed, | | | | rods: attach to an Expansion Joint assembly to |
| (expanded mandrel), manufactured Metal Bellows, | | | | mitigate pressure loads, as well as ancillary forces |
| followed by finish rolling. Rectangular metal sheets are | | | | such as dead weight. * Limit rods: a "fail-safe" addition |
| sheared and rolled into a tube, which is then | | | | which addresses the situation of occasional anchor |
| weld-mated using no filler metal. This longitudinal seam | | | | overload or system malfunction which could cause |
| weld is then "plannished" to match the parent material | | | | bellows expansion beyond tolerance. * Liners: internal |
| thickness. "Bellows," of course, implies convolutions. | | | | sleeves used to protect the internal surface of the |
| Once the welding is complete, and testing to | | | | metal bellows from media which may compromise its |
| tolerance performed, the convolutions are individually | | | | integrity. * Purge Connections: used in tandem with |
| punched, drawing material from the top and bottom | | | | Liners, keep the bellows within high temperature |
| of the tube, thus creating consistency in the | | | | tolerance conditions, such as oil industry applications. * |
| thickness of the Bellows material. Finally, the required | | | | Covers: are used to protect the Metal Bellows |
| "U" shape of the Bellows is implemented through the | | | | Expansion Joints from any detrimental external |
| use of rollers. The Bellows are then trimmed, and | | | | elements. * MAIN ANCHORS: resist the effects of all |
| ready for installation of attachment ends. | | | | forces acting upon them, including pressure thrust, |
| To assure the best performance of Metal Bellows | | | | bellows spring resistance, frictional resistance of pipe |
| Expansion Joints, the design, quality assurance, and | | | | guides, and inertial forces at bends and elbows. * |
| manufacturing practices should be in compliance with | | | | INTERMEDIATE ANCHORS: used to divide a long pipe |
| EJMA, ASME Section VIII and IX, ANSI B31.1, B31.3 | | | | run into shorter individual expanding sections. * |
| and other major industry standards such as UOP. | | | | DIRECTIONAL ANCHORS: permit movement in one |
| The Metal Bellows Expansion Joints may experience | | | | direction only. * PIPE ALIGNMENT GUIDES: control |
| one or a combination of axial, angular, lateral, or | | | | thermal expansion in the system so that the |
| twisting movement. Depending on system | | | | movement applied to the bellows assembly is axial |
| requirements, a variety of unrestrained and/or | | | | only. |
| restrained assemblies, may be utilized. Unrestrained | | | | As an example, if two expansion joints of different |
| Assemblies include the following: * Single Joint | | | | pipe diameters are used in the same section of pipe, |
| Assemblies: a single Metal Bellows welded to either a | | | | such as a line containing a reducer, the pressure |
| flange or pipe end. * Universal Expansion Joint | | | | thrusts are no longer equal. In this case, the anchor |
| Assemblies: the connection of two pipe end or flange | | | | dividing the expansion joints must be a main anchor |
| bellows with a center spool piece. This provides more | | | | designed to withstand the difference in pressure |
| flexibility with respect to axial, and angular movement. | | | | thrust generated by the different size Metal Bellows |
| * Externally Pressurized Expansion Joints: line pressure | | | | Expansion Joints. |
| acts externally on the bellows component through | | | | Piping your media to the desired destination is |
| use of a pressure chamber. More convolutions can be | | | | essential to the success of your business; control the |
| used to control axial movement, and alleviate | | | | heat, movement and pressure on your operation with |
| concerns of bellows instability. | | | | the appropriate use of Metal Bellows Expansion |
| Four extremely effective Restrained Metal Bellows | | | | Joints, and you control the heat, movement and |
| Expansion Joint Assemblies lead the pack: * Tied | | | | pressure on yourself. |
| Single Bellows Assemblies: a combination of the Single | | | | |