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US 4,343,350 AGranted
Double wall tubing assembly and method of making same
AssigneeUop LLC
InventorsBonnie J. Campbell, Thomas G. Counts, James L. Cunningham, Karl J. Youtsey
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AssigneeUop LLC
InventorsBonnie J. Campbell, Thomas G. Counts, James L. Cunningham, Karl J. Youtsey
Estimating the term…
Improved double wall tubing assembly which is especially useful in heat exchangers of the "coil-in-can" type for solar applications has a double wall construction which insures that a leak developing from a failure in either of the walls will not result in a mixing of fluid external to the outer tube with the fluid flowing internally of the inner tube. An outwardly projecting helical fin configuration formed on the outer surface of the inner tube provides an effective heat transfer medium between the inner and outer walls of the tube assembly while defining a spiral flow channel through which leakage entering through either wall can flow and be detected. A method of making the double wall tube assembly is disclosed wherein a finned outer tube is assembled over a previously finned inner tube. The assembled tubes are then brought into firm mechanical contact by the step of forming the assembled tubes into a coil and/or by expanding the inner tube. An additional method is also disclosed wherein a plain outer tube is assembled over a previously formed inner tube and then contacted by finning tools which fin its outer surface and bring its inner diameter into intimate contact with the inner tube.
A double wall heat exchange tube assembly comprising an outer tube portion having external fins along at least the major portion of its length and an inner tube portion inside said outer tube portion, said inner tube portion having integral, generally transverse external fins along a portion of its length, said fins on said inner tube portion having their tips bent over so as to be generally parallel to the axis of the tube assembly, said inner and outer tube portions being in firm, mechanically bonded relation to each other along the finned portions thereof with the bent over tip portions of the inner tube portion contacting the inner wall of the outer tube portion so as to define a helically continuous chamber between the inner and outer finned tube portions in the fin space of the inner tube portion which underlies the bent tip portions, said helically continuous chamber being sufficiently open to permit the flow of leakage fluid therethrough and the detection of leaks through the walls of either tube portion into said chamber, said inner tube portion having a non-smooth configuration over at least a substantial portion of its length within said outer tube portion for inducing turbulence in fluid flowing therethrough.
A double wall tube assembly comprising an outer tube portion having integral, generally transverse, helical fin portions extending externally thereof and an inner tube portion positioned therein, said inner tube portion having integral, generally transverse, helical external fins thereon whose tips are folded over generally parallel to the tube wall and spaced therefrom so as to define an open helical channel, said folded over fin tips being in mechanical contact with the inner wall of said outer tube portion, the inner wall of said inner tube portion having turbulence inducing means formed therein to induce turbulence in fluid flowing therethrough.
Dependencies are inferred from the claim text.