1. Spiral Heat Exchangers – “The Problem Solver”
A fully welded heat exchanger for tough process duties
In Alfa Laval since the 1930s
In total over units sold in a variety of industries
The largest of our welded products with a yearly sale of about
800 units
m2 in total
9/2003

2. Spiral Function Counter-current spiral flow
One fluid from centre to periphery
The other from periphery to center
Co-current flow by reversing one of the sides
Channel spacing is flexible between 1/4 to 1”
“U” value 2-3 times that of a shell and tube
Cover gasket
Channel closure
Channel closure by bending and welding one edge.
Cover gasket seals on each side (prevent by-pass)
9/2003

3. Spiral - the “self-cleaning” HE
Used for tough process fluids
Sewage sludge
PVC slurries
Fermentation broth
Heating of Mineral slurries
Pulp and Paper
Self-cleaning effect with
Horizontal mounting
Single channel
Any deposit will increase the velocity locally and scrub it away
Easy access for mechanical cleaning by removing the covers
9/2003

4. Spiral - deep vacuum condenser
Spirals can be fitted as condensers directly on top of columns
Able to handle deep vacuum (<6 psia) and large volumes with minimal pressure drop
Connecting flange bolted directly to column
Substantially lower installation and pumping costs than large S&T mounted on the ground
Click on picture to run
9/2003

5. Spiral - deep vacuum condenser
Bona Kemi, Malmö, Sweden Two spiral reflux condensers mounted in series on top of a polymerisation reactor. They perform the same duty as the S&T in the background
Norsk Hydro, Bergen, Norway Spiral top condenser installed on the stripper in the cold liquid absorption system that recovers crude oil vaporising during the loading of tankers
9/2003

6. Spiral - slurry steam heaters
Process fluid
Process
fluid
Condensate
Inerts
Slurry in the horizontal single channel in spiral flow to achieve the self cleaning effect
Steam in cross and spiral flow
Örtofta sugar factory, Eslöv, Sweden. Two spirals perform as steam heaters of pre-limed sugar juice. In operation without problems since 1978
9/2003

7. Stud Welding
9/2003

8. Spiral - winding of the body
The heat transfer is made by winding a plate sheet in a mandrill
The sheet has spot-welded studs to ensure the channel spacing
Studs
Mandrill
9/2003

9. Spiral Channel Welding
9/2003

10. Channel Closure Each spiral channel welded closed - no intermixing
ACW - Alternate Channel Welded is standard
Flange or Bar closure
9/2003