External Heating/Cooling Jackets: Half-pipe type

The most commonly used type of heating/cooling jacket in the chemical industry is the half-pipe jacket. This jacket uses a 180° segment of pipe welded directly to the shell in a spiral pattern. 3” is a commonly used pipe size, but other sizes are available. The jacket is often formed from sheet instead of pipe. Appendix EE of the ASME code gives some guidance for half-pipe jacket design.

A major advantage of this jacket type is that higher jacket pressures can be used without a significant increase of the shell thickness. This in turn reduces vessel weight and promotes increased heat transfer through the thinner shell. Low pressure drop is also a benefit of this design, and pressure drop can be lowered further by using multiple zones of jacket. Half-pipe jackets are usually the most cost-effective jacket type for larger vessels such as reactors, and are ideal for cooling water, steam, or heat transfer fluid.

At Ward, we are the “Half Pipe Specialists” and use our proprietary automated process for half-pipe jacket welding. The process uses formed sheet for the jacket, which virtually eliminates jacket butt joints (a common failure point). The process uses a compression fit and twin sub-arc weld heads for consistent and reliable welds throughout the jacket. The final product can withstand the cycling thermal loading that often causes problems in heat transfer jackets.

Schedule a visit to learn more about our unique half-pipe welding process.