| Type: |
Hinged Expansion Joint |
| Size: |
66″ in diameter and 39-3/8″ OAL |
| Material: |
Incoloy 825 / 321 stainless steel |
| Design |
73 PSIG at 986°F with 4.25 degrees of angular rotation |
| Testing: |
Dye Penetrant, X-Ray, PMI, Hydrotest |
These single hinged expansion joints were custom designed by US Bellows for a chemical plant in Saudi Arabia to manage the critical piping systems. The units are 66″ in diameter and 39-3/8″ OAL. The bellows were fabricated from Incoloy 825 with the weld ends, hinges, liner, and cover from 321 stainless steel. The expansion joints were designed for an operating pressure of 73 PSIG at 986°F with 4.25 degrees of angular rotation. All units were dye-penetrant tested and x-ray tested on each bellows and pipe longitudinal weld seams, PMI tested on each alloy component, and ultrasonic tested on each alloy steel plate prior to shipment. Hinged expansion joints contain hinges or pivots which allow the unit to bend in a single plane.
We’ve supplied this type of expansion joint for both methanol and ammonia plants. They are also used in piping systems for air, steam, gas turbines, reformer ducts, and burners. These units are designed to restrict axial deflection in extension or compression. The hinge mechanism is designed to contain full-pressure thrust. Also, because of the hinge mechanism’s design, shear loads, such as from the weight of adjacent piping, can be accepted by this pipe expansion joint, relieving the piping designer of having to provide additional supports and anchors required by the single type.
Product Overview
US Bellows designs and manufactures single hinged expansion joints engineered to absorb angular rotation in critical piping systems. Compliant with EJMA (Expansion Joint Manufacturers Association) standards, these units are built to handle extreme operating conditions — including high temperature, high pressure, and corrosive media — across petrochemical, power generation, and industrial process applications.
Featured Project: Saudi Arabia Chemical Plant
This custom-engineered single hinged expansion joint was manufactured for a chemical plant in Saudi Arabia serving critical piping infrastructure. The units measure 66″ in diameter with a 39-3/8″ overall length. Bellows were fabricated from Incoloy 825, with weld ends, hinges, liner, and cover constructed from 321 stainless steel. The joints were designed for an operating pressure of 73 PSIG at 986°F (530°C), with an angular rotation capacity of 4.25°. Prior to shipment, all units underwent dye-penetrant and radiographic (X-ray) testing on every bellows and pipe longitudinal weld seam, Positive Material Identification (PMI) on each alloy component, and ultrasonic testing on all alloy steel plate — ensuring full traceability and compliance with the project’s quality requirements.
How Single Hinged Expansion Joints Work
Single hinged expansion joints incorporate a hinge and pivot mechanism that permits angular rotation in a single plane while mechanically restraining axial movement in both extension and compression. Unlike unrestrained expansion joint types, the hinge assembly is rated to absorb full pressure thrust loads, eliminating the need for main anchors in many piping configurations. Because the hinge mechanism also accepts shear loads — including the dead weight of adjacent piping — fewer external pipe supports and guides are required, reducing installed system cost and structural complexity. This behavior is consistent with EJMA’s guidance on restrained expansion joint systems. To accommodate full angular rotation, single hinged expansion joints are typically installed in pairs or sets of three with appropriate anchor and guide arrangements, as outlined in EJMA standards.
Applications
US Bellows has supplied single hinged expansion joints for methanol and ammonia plants, steam and gas turbine exhaust systems, reformer and process gas ducting, combustion air and burner systems, and a wide range of high-temperature gas and air piping applications. These units perform reliably where fixed supports cannot manage thermal growth and where the pressure thrust forces must be fully restrained at the joint itself. US Bellows differentiates through full in-house fabrication, custom metallurgy selection, and rigorous third-party testing documentation delivered with every order.
Materials of Construction
Bellows are available in Incoloy 825, 321 SS, 316L SS, Inconel 625, Hastelloy C-276, and other high-performance alloys depending on process chemistry and temperature range. End fittings, liners, and hinge hardware are material-matched to the process environment and fabricated to customer specification, with full PMI verification on all alloy components as standard practice.
Why Choose US Bellows
US Bellows delivers EJMA-compliant design and documentation with full in-house fabrication from raw plate through final assembly. Every unit is custom-engineered for the specific operating conditions of the application — including non-standard diameters, pressures, and temperatures. Comprehensive NDE including dye-penetrant, radiographic, ultrasonic, and PMI testing is standard on all alloy components. US Bellows has a proven global supply record serving methanol, ammonia, refinery, and power generation facilities, and units are available with ASME Code stamping and third-party inspection upon request.
PT&P REF. ORIGINAL POST 06182019
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