Shell-and-helix heat exchanger is intended for use in ammonia/carbon dioxide cascade refrigeration systems. The heat exchanger design offers all stainless steel construction for corrosion resistance and long life. The compact unit provides a large heat transfer surface in small volume. Other features include tube-side (CO2) pressure capability as high as 1,700 psig (119 bar). The multiple-helix design permits expansion and contraction of tubes during large changes in temperature and pressure with low resulting strain and stress reducing the risk of failure and leaks. Nesting of the multiple helically formed tubes in both radial and axial directions results in equal spacing of the tubing and uniform flow distribution on the shell side. Multiple shell-side connections allow reversing the flow of the ammonia and CO2, which permits reverse cycle hot-gas defrosting.

Colmac Coil Co.