Cleanable tube within a tube heat exchanger and method of forming modular headers therefor

Claim 2

In a ''''tube within a tube'''' heat exchanger including inner and outer fluid headers sealingly coupled, respectively, to opposite ends of inner and outer tubes defining a heat exchange tube assembly, the improvement wherein: each header comprises a plurality of open ended, identical, axially stacked, tubular segments in module form, each segment including opposed small and large diameter holes within its side wall, respective headers at each end of said tube assembly being oriented with their small diameter holes facing each other, each small diameter tube extending beyond the ends of said large diameter tube for each tube assembly and passing through both small diameter holes for each header, and sealed thereto, each large diameter tube being sealed within a large diameter hole of said inner header and removable end plugs sealingly carried by said large diameter holes within said outer header to facilitate cleaning of said small diameter tubes while allowing easy location of any loss of seal between the sealed components of said heat exchanger.

Claim 3

The ''''tube within a tube'''' heat exchanger, as defined in claim 1, wherein each tubular segment comprises a cylindrical drawn metal body having an enlarged rim on one end to facilitate stacking and an imperforate baffle disc within said enlarged annular lip of selected segments as well as the end of the adjacent shell segment to facilitate seal coupling of these elements while forming the flow paths of said heat exchange fluids through said heat exchanger.

Claim 4

The ''''tube within a tube'''' heat exchanger, as claimed in claim 1, wherein said tubular segments are drawn from thin metal material, and said small and large diameter holes are formed by punching in portions of said tubular segment side wall to define an annular rim coaxial with each hole.

Claim 5

The ''''tube within a tube'''' heat exchanger, as claimed in claim 3, wherein the axial ends of said headers are closed off by domed-shaped end caps sealed thereto.

Claim 6

A multiple row, readily cleanable, tube within a tube heat exchanger assembly characterized by completely exposed brazed joints throughout the assembly, comprising: pairs of inner and outer substantially tubular fluid headers brazed to opposite ends of inner and outer tubes defining heat exchange tube assemblies for each vertical array, each of said headers constituting a plurality of identical open ended, cup-shaped, axially stacked drawn shell segments, each segment including opposed small and large diameter holes within its sidewall, respective headers at each end of said tube assemblies being oriented with their small diameter holes facing each other to commonly receive an end of said small diameter tube extending beyond said large diameter tube and being brazed thereto, the large diameter tubes extending within the large diameter hole within said inner headers and brazed thereto, said large diameter holes within said outer header carrying removable threaded end plugs for facilitating cleaning of the inner tubes of said heat exchanger, and a plurality of mechanical coupling means for coupling at least two vertical stacked arrays, said coupling members comprising a threaded bolt extending between adjacent large tubes of the heat exchanger tube assemblies for all vertical stacked arrays the width of said heat exchanger assembly, and a plurality of spacer discs carried on said threaded bolt with at least one spacer disc between each vertical stacked array and having arcuate grooves corresponding to the periphery of the outer tube of said tube assembly and being of a thickness to space said vertical stacked array of tube assemblies from each other and a nut for mechanically locking said spacers to said tube assemblies.

Claim 7

A multiple row, readily cleanable, tube within a tube heat exchanger assembly characterized by completely exposed brazed joints throughout the assembly, comprising: pairs of inner and outer substantially tubular fluid headers brazed to opposite ends of inner and outer tubes defining heat exchange tube assemblies for each vertical array, each of said headers constituting a plurality of identical open ended, cup-shaped, axially stacked drawn shell segments, each segment including opposed small and large diameter holes within its sidewall, respective headers at each end of said tube assemblies being oriented with their small diameter holes facing each other to commonly receive an end of said small diameter tube extending beyond said large diameter tube and being brazed thereto, the large diameter tubes extending within the large diameter hole within said inner headers and brazed thereto, said large diameter holes within said outer header carrying removable threaded end plugs for facilitating cleaning of the inner tubes of said heat exchanger, and a plurality of mechanical coupling means for coupling at least two vertical stacked arrays, said coupling members comprising a threaded bolt extending between adjacent large tubes of the heat exchanger tube assemblies for all vertical stacked arrays the width of said heat exchanger assembly, and a plurality of spacer discs carried on said threaded bolt with at least one spacer disc between each vertical stacked array and having arcuate grooves corresponding to the periphery of the outer tube of said tube assembly and being of a thickness to space said vertical stacked array of tube assemblies from each other and a nut for mechanically locking said spacers to said tube assemblies.