Double wall heat exchanger tube bending methods

[doublebend]

Am I correct in understanding some heat exchangers tubing is tube in tube and there is flow in annular space between tube.
If so how are these tubes bent toghether.Is there a support between them?
Our double wall bending system employes a sleeve and allows flow but is only in aerospace fuel systems.If it can be used for and is better than current heat exchange bending methods is what I wish to find out.

Any info or resources to direct appreciated.

Steve

Steve Wolf
Wolfbend LLC

http://www.wolfbend.com

 

[stanlsimon]

My recollection of the double wall heat exchangers is that the annular space consists of grooves cut into the outer side of the inside tube. They probably use a thicker copper tube for this application. I would check out Bell and Gossets web site, they used to call their double wall heat exchanger "diamond back" because the grooves were cut in two crossing spirals.

 

[doublebend]

Thanks Stan----.I found their website some drawings show bent tube bundles I have to investigate to see if they are tube in tube bundles.They look to be single wall tubes in the cylinders/containers.

Steve

Steve Wolf
Wolfbend LLC

http://www.wolfbend.com

 

[rjw57]

I am not positive about this, but I understand that some form of a compacted powder is used between the tubes to act as a support during bending. The powder is obviously removed afterwards to create the annulus.

 

[doublebend]

Rj-- Our bending system has been replacing that method in aerospcae fuel lines.Sound like you may be talking about Cerro bend which is a hot metal/wax that has to be melted out.Maybe there is a powder method I am not aware of also. Our sleeve remains in the annular space it does allow for fluid flow on the outer space.I am looking at how its done and how much flow is actually needed before we redesign things..

Thanks

Steve

Steve Wolf
Wolfbend LLC

http://www.wolfbend.com