Tube Bundles to fit all OEM Heat Exchangers

Shell Assembly

The shell is typically constructed from pipe or rolled plate steel, with steel being the most common material due to cost efficiency. For high-temperature or corrosive applications, alternative alloys may be specified. Maintaining a consistent inner diameter (“roundness”) is critical to minimize fluid bypass around baffles, which can reduce performance. Roundness is achieved through expansion methods or double rolling after seam welding; in extreme cases, shells may be cast and machined to specification. When inlet fluid velocity is high, an impingement plate is installed to distribute flow evenly, reducing erosion, vibration, and cavitation while maximizing usable tube surface.

Tubes

Heat exchanger tubes, commonly ranging from 5/8" to 1.5" diameter, are manufactured from materials such as carbon steel, copper alloys, stainless steel, Hastelloy, Inconel, or titanium. Tubes may be seamless or welded, with options such as finned or internally enhanced surfaces to improve heat transfer. Finned tubes are especially beneficial when shell-side heat transfer coefficients are lower than tube-side. U-tube designs accommodate thermal expansion but offer slightly less surface area and are more difficult to clean and repair compared to straight tube bundles.

Bonnets and End Channels

Bonnets (end channels) regulate tube-side fluid flow and are typically cast or fabricated, then bolted and gasketed to the tube sheet. Multi-pass designs use pass ribs to direct flow evenly through the bundle, maintaining consistent velocity and pressure drop. Most exchangers use up to four passes, though specialty designs may include more. Materials for smaller cast bonnets commonly include iron, steel, bronze, or stainless steel, with connection types such as NPT, flanged, SAE, tri-clamp, and BSPP available.

Baffles

Baffles serve as tube supports during assembly and, in operation, reduce vibration while directing shell-side fluid across the tube bundle to increase turbulence and heat transfer efficiency. Proper shell roundness and tight tolerances are essential to prevent performance loss from fluid bypass. Baffles are stamped or machined from materials compatible with shell-side fluids and are precisely manufactured to allow tube replacement while minimizing leakage. In liquid applications, baffles typically occupy 20–30% of shell diameter; in gas applications requiring lower pressure drop, 40–45% is common. Even spacing ensures adequate tube support, controlled pressure drop, and uniform fluid velocity.