Alfa Laval’s spiral heat exchangers are based on an ingeniously simple construction. Two metal strips welded to form a spiral body containing two separate continuous and leak proof channels. The hot medium passes through one channel while the cold medium flows in the other channel. Heat transfer takes place through the channel walls.
– A solution for the hardest heat exchanger duties and applications
Each channel is normally welded closed on one side to prevent cross-contamination and remains open on the opposite side, which faces a cover and which is sealed with a gasket. A pressure-resistant shell envelops the spiral body and removable covers are fastened to each end with hook bolts. The inlet and outlet connections for both channels are attached to the shell and to the covers.
The most distinguishing feature of the spiral heat exchanger is its single channel concept. The entire flow of each medium is forced through one single channel. This construction effectively prevents the accumulation of debris for the spiral heat exchanger.
Advantages of Spiral Heat Exchangers
Self Cleaning
The scrubbing effect in each single channel removes deposits as they form. Suspended solids tend to settle during low flow rates or shutdown, which often leads to clogging in multiple-channel designs. This cleaning feature is particularly advantageous to combat clogging in a horizontally mounted unit. Particles tend to accumulate in the bottom of each channel curvature. This resulting restriction of the channel cross-section increases the fluid velocity at the exact area affected and any deposits are immediately flushed away.
Low Fouling
The high turbulence created by the continuously curving channels minimizes fouling and scaling tendencies. This means that the spiral design improves heat transfer surface than a shell-and-tube heat exchanger. Moreover, this also means that the design requires less frequent cleaning.
Easy Access
Removing the covers on both ends of the spiral heat exchanger makes the entire length of each of the channels easily accessible for inspection or mechanical cleaning, if necessary. Should scaling or fouling occur, cleaning-in-place is effective without even opening the unit.
Small Space Requirements
The circular arrangement of the two channels makes an extremely compact heat exchanger. For example, 100 m² (1080 ft²) of heat transfer surface fits into a heat exchanger only one metre in diameter and 1.5 metres long. The only service space required is that for the removal of the covers.
Applications of Spiral Heat Exchangers
The efficient performance of the Alfa Laval spiral heat exchanger makes it particularly suited for such liquid-to-liquid duties as:
- clogging slurries such as PVC slurries
- clogging particle-laden and fibrous media such as TMP condensate in pulp and paper production
- clogging and erosive media such as alumina hydrate slurries
- fouling media such as waster water / sewage sludge
- high-viscosity media such as heavy oil
- non-Newtonian fluids such as fermenting broth in pharmaceuticals processing
- high-temperature fluids with a close temperature approach such as vegetable oil
- Black liquor heaters
Call us today. Tel: 905.940.0961 or by Email: info@www.valutechinc.com