Two of the most fundamental components in pressure equipment are formed heads and expansion joints, and Roben Manufacturing produces both in-house. We form ASME flanged-and-dished (F&D) heads on our own head-forming equipment and fabricate flanged-and-flued expansion joints that absorb the thermal movement between a heat exchanger's shell and tubes.
Producing these components ourselves means control over quality, dimensions, and schedule. Rather than waiting on outside suppliers for critical parts, we form heads up to large diameters and build expansion joints matched precisely to the equipment they serve.
Formed Heads and Thermal-Movement Components, In-House
Flanged-and-dished heads close the ends of pressure vessels and are among the most common head types in process equipment. Our head-forming capability produces F&D heads up to 102 inches in outside diameter and 5/8-inch thickness, along with cones up to 108 inches and flanged-and-flued heads up to 48 inches. Forming heads in-house lets us control the knuckle radius, dish radius, and overall geometry that affect both code compliance and fit.
Flanged-and-flued expansion joints are the rugged, thick-walled answer to differential thermal expansion in fixed-tubesheet heat exchangers. When the tubes and shell grow at different rates, the resulting stresses can damage the tube-to-tubesheet joints unless the shell can flex. A flanged-and-flued joint provides that flexibility while remaining robust enough for demanding pressures and temperatures, unlike thin-walled bellows in many heavy-duty services.
We design these expansion joints to the movement, pressure, and temperature of the specific exchanger, verifying that they accommodate the calculated thermal displacement over the expected number of cycles without fatigue failure. The joint becomes an integral, code-compliant part of the shell.
Both heads and expansion joints ship with the material and forming documentation appropriate to code construction. Because they are produced under the same quality system as the vessels and exchangers they serve, fit and consistency are assured.
Why Choose Roben Manufacturing
- In-house head forming. We form F&D heads, cones, and flanged-and-flued heads on our own equipment, controlling geometry, quality, and schedule.
- Large-diameter capability. F&D heads to 102 inches OD, cones to 108 inches, and flanged-and-flued heads to 48 inches are formed in-house.
- Rugged expansion joints. Flanged-and-flued joints absorb thermal movement while remaining robust for demanding pressures and temperatures.
- Application-specific design. Expansion joints are designed to the exchanger's actual movement, pressure, temperature, and cycle life.
- Consistent quality and fit. Heads and joints are produced under the same quality system as the equipment they serve.
Key Features & Capabilities
- ASME flanged-and-dished (F&D) head forming
- F&D heads up to 102 inches OD and 5/8-inch thickness
- Cone forming up to 108 inches OD
- Flanged-and-flued heads up to 48 inches OD
- Flanged-and-flued expansion joint fabrication
- Expansion joints designed to thermal movement and cycle life
- Knuckle- and dish-radius control for code compliance
- Integration of expansion joints into the exchanger shell
- Material and forming documentation for code construction
- Components produced under one quality system
Applications & Industries Served
- End closures for pressure vessels and reactors
- Heat exchanger shell and channel heads
- Fixed-tubesheet exchangers requiring thermal flexibility
- Equipment with significant differential thermal expansion
- Cone transitions in process vessels
- Replacement heads and expansion joints for existing equipment
Codes, Standards & Quality Assurance
Roben Manufacturing fabricates under a controlled quality system and holds the ASME U Certificate of Authorization, with registration through the National Board of Boiler and Pressure Vessel Inspectors. Every applicable project is supported by material test reports, qualified welding procedures, nondestructive examination records, and complete documentation.
Relevant standards and resources include: ASME Boiler and Pressure Vessel Certification; TEMA — Tubular Exchanger Manufacturers Association.
Frequently Asked Questions
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