| Piping; lots of piping, maybe miles of it. Look at | | | | With respect to restrained Metal Expansion Joint |
| the schematic. Straight lines; bends; right angles; | | | | Assemblies, four clear choices emerge: – |
| every twist and turn requires expansion joints. It | | | | Tied Single Bellows Assemblies combine the Single |
| makes the Los Angeles freeway system looks | | | | Bellows Assembly with tie rods, thereby increasing |
| like child's play. Whether the piping is one inch | | | | piping system design flexibility. Main anchors are |
| diameter, or 200; whether the system operates | | | | unnecessary as the system thrust pressure is |
| at full vacuum, or 2000 psig, at full capacity, there | | | | carried by tie rods attached to the flange or pipe |
| is considerable pressure. Depending on the | | | | with lugs. – Tied Universal Assemblies, |
| medium, the system may have to accommodate | | | | similar in manufacture to Universal Assemblies, |
| 4000 degree heat or -325 degree cold. Pressure | | | | limit lateral offset and angular movement by |
| and temperature cause expansion and contraction. | | | | utilizing tie rods to absorb pressure thrust. |
| The result is stress on the system and the | | | | – Use of Hinged Bellows Assemblies limits |
| system engineer. The mission? Control the flow | | | | angular movement to one plane. The configuration |
| and keep the operation running at optimal capacity | | | | of two or three Hinged Bellows Assemblies is |
| and efficiency. | | | | typically employed in high pressure piping situations |
| The answer? High quality Metal Bellows Expansion | | | | to handle large amounts of expansion. – |
| Joints. Expansion joints allow movement of a | | | | Finally, Gimbal Bellows Assemblies are engineered |
| medium through a piping system while containing | | | | to allow angular movement in all planes, while |
| the medium, and controlling system pressure. | | | | absorbing pressure thrust and torsional |
| Thermal growth or diminution, equipment | | | | movement. Gimbal Assemblies, when paired, or |
| movement, vibration or pressure anomalies can | | | | used in conjunction with a Single Hinged unit, are |
| cause movement in a piping system. Metal | | | | particularly suited to maximize absorption in |
| Expansion Joints are an excellent, and often | | | | multi-planer piping systems. |
| essential, solution, to piping system movement. | | | | Complimenting and enhancing the various Metal |
| The expansion joints may experience one or a | | | | Bellows Expansion Joint assemblies are numerous |
| combination of axial, (straight line); angular, | | | | options and accessories. Ties rods, referred to |
| (longitudinal rotation); lateral, (shear); or torsional, | | | | above, typically devised as rods or bars, attach to |
| (twisting), movement. Insertion of these metal | | | | an expansion joint assembly for the purpose of |
| expansion joints into the system, of course, | | | | mitigating both the inevitable pressure loads, as |
| requires end connections. End connections may | | | | well as ancillary forces such as dead weight. Limit |
| require flanges, or specialized flanges, including | | | | rods are a "fail-safe" methodology designed to |
| "slip-on, "angle," or perhaps "Vanstone" modified | | | | address the situation of occasional anchor |
| flanged ends with the flexibility of resolving | | | | overload or system malfunction which, otherwise, |
| bolt-hole misalignment. Weld end connections can | | | | could cause metal bellows joint expansion beyond |
| also be used to mate metal bellows expansion | | | | design parameters. Limit Rods are a precautionary |
| joints to any pipe or duct in a system. A variety | | | | measure that does not come into play under |
| of unrestrained and restrained metal bellows | | | | normal operating conditions. Liners are internal |
| expansion joints are available to increase system | | | | sleeves which are used to protect the internal |
| integrity. | | | | surface of the metal bellows from media which |
| Unrestrained metal expansion joint assemblies | | | | may compromise its integrity. In high temperature |
| include: – Single Joint Assemblies, the | | | | media conditions, such as oil industry applications, |
| simplest type, consisting of a single metal bellows | | | | Purge Connections are used in tandem with Liners |
| welded to either a flange or pipe end. – | | | | to keep the bellows within acceptable tolerances. |
| Universal Expansion Joint Assemblies allow more | | | | Covers, otherwise known as "shrouds," are used |
| flexibility with regard to axial, lateral and angular | | | | to protect the Metal Bellows Expansion Joints |
| movement, by connecting two bellows with flange | | | | from any external elements which might cause |
| or pipe ends with a center spool piece. – | | | | concern. |
| Externally Pressurized Expansion Joints allow line | | | | In sum, the appropriate use of Metal Bellows |
| pressure to act externally on the bellows | | | | Expansion Joints is critical to the operating |
| component through inclusion of a pressure | | | | "up-time" of any significant piping system. |
| chamber. This configuration provides more | | | | Operations, production and, ultimately, profit are |
| convolutions to be used to control significant axial | | | | tied to the smooth and seamless flow of media |
| movements, and negates concerns of bellows | | | | through the intricate, and often unseen, "highway" |
| instability. Standing media concerns are allayed by | | | | of fluid transmission, whether liquid, gaseous, |
| the benefit of self-draining convolutions. Proper | | | | super-heated or super-cooled. "Forewarned is |
| installation requires appropriate anchors and guides. | | | | forearmed" is no cliche; either prepare or repair. |