US3324941A

US3324941A - Heat exchanger with expansible tube seal

Info

Publication number: US3324941A
Application number: US335247A
Authority: US
Inventors: Raymond T Divers
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 1964-01-02
Filing date: 1964-01-02
Publication date: 1967-06-13
Anticipated expiration: 1984-06-13

Description

June 13, 1967 R. 'r. DIVERS 3,324,941

HEAT EXCHANGER WITH EXPANSIBLE TUBE SEAL I 7 Filed Jan. 2, 1964 2 Sheets-Sheet 1 O00 O00 O00 000 FIG. 2 T2 24 INVENTOR. RAYMOND T. DIVERS.

ATTORNEY.

June 13, 1967 R. T. DIVERS 3,324,941

HEAT EXCHANGER WITH EXFANSIBIJE TUBE SEAL Filed Jan. 2, 1964 2 Sheets-Sheet 2 ,22 B 3 {C 9s INVENTOR.

RAYMOND T. DIVERS.

ATTORNEY.

United States Patent 3,324,941 HEAT EXCHANGER WITH EXPANSIBLE TUBE SEAL Raymond T. Divers, Carniilus, N.Y., assignor to Carrier Corporation, Syracuse, N.Y., a corporation of Deiaware Filed .ian. 2, 64. Ser. No. 335,247 11 Claims. (Ci. 165-173) This invention relates to heat exchange apparatus, and more particularly to a heat exchanger for use in refrigeration systems.

Heat exchangers may be thought of as devices for bringing primary heat exchange medium into heat exchange relationship with secondary heat exchange medium. A typical heat exchanger includes a plurality of longitudinally disposed heat exchanger tubes in a housing. In a heat exchanger of this type the area surrounding the exterior surfaces of the plural heat exchanger tubes may be in cornmunication with the primary heat exchange medium while the area bounded by the interior surfaces of the heat exchanger tubes communicates with the secondary heat exchange medium. By this construction the plural heat exchanger tubes serve as the intermediary for bringing primary heat exchange medium into heat exchange relationship with the secondary heat exchange medium.

The efiicacy of a heat exchanger requires that the primary and secondary heat exchange mediums be isolated one from the other. Since the plural heat exchanger tubes constitute the sole bridge between primary and secondary heat exchange mediums the seal between primary and secondary heat exchange mediums at each of the plural heat exchanger tubes is of critical importance.

Where heat exchangers of the type described are disposed in positions other than vertical, the heat exchanger tubes tend to sag. Tube sag may place an excessive strain on the seal between primary and secondary heat exchange mediums at each of the plural heat exchanger tubes with possible impairment or rupture thereof. Additionally, the amount of sag of each of the plural heat exchanger tubes may vary, destroying the design spacing between each of the tubes and bringing tubes into contact with one another. The flow of first and second heat exchange mediums through the heat exchanger may induce the heat exchanger tubes to vibrate causing contacting or closely adjacent tubes to strike one another.

To obviate sag in heat exchanger tubes, additional supports, commonly known as tube support sheets, may be placed at selected intervals in the heat exchanger housing. Each of the tube support sheets has a plurality of spaced tube receiving openings therein through which the heat exchanger tubes pass. The surrounding tube support sheet structure is relied upon to limit movement of the tube in a radial direction and maintain selected spacing between tubes.

In constructions where tube support sheets are utilized, it may be appreciated that the most effective support structure for maintaining the heat exchanger tubes in predetermined spaced relation relative to the heat exchanger housing and to each other is a support sheet having tube receiving openings dimensioned approximately equal to or slightly less than the outer dimension of the heat exchanger tubes. By this construction each heat exchanger tube is rigidly positioned against movement in a radial direction at the tube support sheet. However, assembly of the heat exchanger by the expedient of moving the plural heat exchanger tubes axially through openings in the support sheet or sheets is then impossible or extemely difficult. To permit the axial movement of the heat exchanger tubes for ready assembly of the heat exchanger, tube support is compromised by making the tube support sheet openings larger than the outer dimension of the exchange tubes. This compromise arrangement provides a degree of support for each heat exchanger tube, and at the same assign ice time permits movement of the heat exchanger tubes through the support sheets during assembly and disassembly of the heat exchanger. It does not, however, support the heat exchanger tubes tightly enough to eliminate sag of tubes between supports, and tube vibration.

To more effectively support the heat exchanger tubes, each heat exchanger tube may be expanded into contact with each of the tube support sheets. This construction permits the use of support sheet openings with a dimension greater than the outer dimension of the heat exchanger tubes whereby assembly of the heat exchanger tubes is facilitated and at the same time results in a high degree of tube support through the subsequent expansion of each tube into tight engagement with the support sheet. However, this construction is expensive, time-consuming and often impractical. Where heat exchangers have a substantial axial length with a great number of relatively small diameter heat exchanger tubes and plural spaced support sheets, the magnitude of the problem facing the assembler in accurately locating and expanding that portion only of each heat exchanger tube opposite each of the tube support sheets through which the tube passes may be readily appreciated.

Conventional tube support sheets are normally formed from metal, usually steel. Contact between the steel support sheet and the outer surface of the heat exchanger tubes which are normally copper may result in galvanic erosion. This may be enhanced by the particular heat exchange fiuid utilized in the system and by any tube vibration. Where the tube support sheet is formed from the same metallic material as the heat exchanger tubes, erosion induced by vibration of the heat exchanger tubes may occur. To obviate tube erosion, each heat exchanger tube should preferably tightly engage the support sheet surface defining the tube receiving opening. However, as noted heretofore, the known technique of expanding each tube into tight engagement with each of the tube sheets through which the tube passes is often impractical and always expensive.

It is a principal object of the present invention to provide a new and improved apparatus for maintaining heat exchanger tubes in predetermined spaced relationship relative to one another and to the heat exchanger.

It is an additional object of this invention to provide a unique support apparatus for heat exchanger tubes enabling the heat exchanger tubes to be moved through openings in the support apparatus during assembly of the heat exchanger, the support apparatus being operable during heat exchanger use to tightly grip each heat exchanger tube to prevent movement thereof.

It is a further object of the present invention to provide a novel tube support sheet construction operable to tightly grasp the outer peripheral surface of heat exchanger tubes when exposed to heat exchange medium.

it is an object of the present invention to provide a new and improved method of making tube support sheets for heat exchanger apparatus.

It is a further object of the present invention to provide a new and improved tube support sheet structure.

This invention relates to a structure for supporting heat exchanger tubes in predetermined spaced relationship one to another, the combination comprising first and second members having plural axially aligned openings therein, each pair of openings being adapted to receive a heat exchanger tube therethrough, and expansible means tightly held between the first and second members at each of the tube openings operable upon exposure to heat exchange medium to expand into contact with the heat exchanger tubes to secure the heat exchanger tubes to the first and second members.

This invention further relates to the method of forming a tube support sheet for use in a heat exchanger having a plurality of spaced heat exchanger tubes therein, the steps which consist in placing ring-like expansible elements on a first tube support sheet part having a plurality of tube receiving openings therethrough opposite to and coaxial with each of the tube receiving openings, disposing a second tube support sheet part having a like number of similarly spaced tube receiving openings therein oppos'te the first tube support sheet part on the expansible e1..- ments with the tube receiving openings thereof coaxial therewith, and bonding the first and second tube support sheet parts together to form a unitary tube support sheet.

Other objects will be apparent from the ensuing description and drawings in which:

FIGURE 1 illustrates schematically a refrigeration system incorporating the present invention;

FIGURE 2 is a cross sectional view taken along lines 11-11 of FIGURE 1 showing the tube support sheet;

FIGURE 3 is an enlarged fragmentary cross sectional through the tube support sheet shown in FIGURE 2 illustrating the expansi-ble tube gripping elements in expanded condition; and

FIGURE 4 is a view of an apparatus for fabricating tube support sheets.

Referring particularly to FIGURE 1 of the drawings, there is shown a refrigeration system embodying the heat exchanger tube support structure of the present invention. The refrigeration system includes a compressor 12 having a suitable drive motor 14. Compressor 12 may be of any suitable type, for example, centrifugal, rotary or reciprocating; if desired, compressor 12 may be housed with motor 14 to form a hermetic unit. It is understood that the present invention may be embodied in absorption type refrigeration systems.

Compressor 12 compresses vaporous primary heat exchange medium or refrigerant flowing through line 3 from the heat exchanger 2, acting as an evaporator. The compressed gaseous refrigerant is discharged through line 11 into heat exchanger 20, acting as a condenser. Gaseous refrigerant entering heat exchanger is liquefied through heat transfer with a secondary heat exchange medium, for example, water circulating through the heat exchanger tubes 22. Liquid refrigerant from heat exchanger 20 passes through line 24 and suitable expansion means 26,

for example, a thermal expansion valve, through line 36 to the heat exchanger 2. Expansion means 26 provides the requisite pressure drop between the heat exchangers during system operation. Liquid refrigerant in heat exchanger 2 is vaporized through heat transfer with the media to be cooled or chilled, for example, water circulating in the heat exchanger coils thereof.

Heat exchanger 20 comprises a generally cylindrical shell or housing 40 with opposite end members or

tube sheets

42, 43 sealingly attached thereto to define cylindrical compartment 41.

Tube sheets

42, 43 support plural heat exchanger coils or tubes 22 passing through compart ment 41. A pair of

headers

45, 46 are sealingly attached to

tube sheets

42, 43 respectively and define therewith end compartments 47, 48. Compartment 47 is separated by member 50 into inlet and discharge chambers 52, 54 respectively in communication with suitable heat transfer medium.

Tube sheets

42, 43 are each provided with an equal number of spaced

openings

60, 61 therethrough, each of the openings 6%) in tube sheet 42 being in axial alignment with a corresponding opening 61 in the opposite tube sheet 43. The terminal ends of each heat exchanger tube 22 pass through a pair of axially aligned

openings

60, 61. Each terminal end of the heat exchanger tubes 22 may be expanded by suitable means (not shown) into tight engagement with the inner surface of the

tube sheet

42 or 43 defining the

openings

60, 61 respectively to tightly seal compartment 41 from the opposite end compartments 47, 48. Heat exchanger tubes 22 may be grouped at 21, 23 into what are commonly known as tube bundles. Tube bundles 21, 23 communicate inlet and discharge cham- .4 bers 52, 54 of compartment 47 with the compartment 48.

Refrigerant lines

11 and 24 communicate the heat exchanger compartment 41 with the system compressor 12 and expansion means 26 respectively.

During operation of the refrigeration system, cooling medium from conduit 56 flows through inlet chamber 52 and heat exchanger tube bundle 21 into compartment 48, and from compartment 48 through heat exchanger tube bundle 23 and outlet chamber 54 into discharge conduit 57. Gaseous refrigerant from the compressor 12 passes through line 11 into compartment 41 of the heat exchanger 20. Liquid refrigerant in compartment 41 flows through line 24 and expansion means 26 to heat exchanger 2.

Referring to FIGURES l and 2 of the drawings, one or more tube support sheets or baffies 70 are shown. Sheets 70 may be formed with paired diametrically opposite arcuate sides 71 and planar sides 72 respectively. Arcuate sides 71, having a radius substantially equal to the radius of cylindrical heat exchanger shell 40, abut the inner surface of shell 46.

In constructions where it is intended that tube support sheets 70 additionally function as baffies to route the flow of refrigerant through heat exchanger compartment 41, tube support sheet 7% may be formed with an arcuate side terminating in a single planar side. The arcuate side, at a radius substantially equal to the radius of cylindrical heat exchanger shell 40, abuts the inner surface of the shell 40.

A plurality of openings 74 having an inner dimension slightly greater than the outer dimension of the heat exchanger tubes 22 is provided in each tube support sheet 70. Each of the openings 74 is disposed in axial alignment with a corresponding pair of

openings

60, 61 in

tube sheets

42, 43 respectively. Tube support sheet or sheets 7 0 are located within cylindrical heat exchanger compartment 41 in predetermined spaced relationship to

tube sheets

42, 43. Preferably, tube support sheet or sheets 70 are fixedly secured to the inner surface of shell 40 by suitable means (not shown). The coaxial relationship between each of the plural tube receiving openings in the support sheet 71 and a pair of tube receiving openings in

support sheets

42, 43 establishes a substantially straightline path for the heat exchanger tubes.

Use of supporting structure of the type described heretofore having openings therein for receiving heat exchanger tubes presents two diametrically opposite problems. In order to assemble the heat exchanger, and to per mit removal of one or more heat exchanger tubes for repair or replacement, the tube openings in the support sheet or sheets must have a dimension greater than the outer dimension of the heat exchanger tubes. By this means relative movement between the tubes and the support sheets, necessary during assembly of the heat exchanger, may be effected. Efiicient tube support, however, decrees that the support sheet closely surround, and preferably tightly grip, the heat exchanger tube. It is appreciated therefore that if the dimension of the support sheet opening too closely approximates the outer dimension of the heat exchanger tube, tube support may be realized at the expense of very difficult, or impossible, movement of the heat exchanger tubes through the support sheet openings. If the dimension of the support sheet openings be sufiiciently great thereby permitting ready insertion, and withdrawal, of the heat exchanger tubes, excessive tube vibration, and tube sag between adjacent supports may occur.

Applicants novel ararngement, hereinafter described, provides a tube support sheet with tube receiving openings therein large enough to permit ready movement of the heat exchanger tubes therethrough during assembly or disassembly of the heat exchanger, the tube support sheet being operable to tightly grip the heat exchanger tubes therein during heat exchanger use.

In FIGURE 3 of the drawings, an enlarged view of applicants novel heat exchanger tube support sheet is therein shown. Tube support sheet or baffle 70 is comprised of a relatively rigid member having a plurality of spaced tube receiving openings or passages 74 therethrough. A portion of each of the openings 74 is comprised of a material adapted on exposure to the system refrigerant to expand or swell radially inward into abutting engagement with the heat exchanger tube therein as will be particularly explained hereinafter. It is understood that the size, orientation, and number of tube openings 74- bear a direct relationship to the size, orientation, and number of heat exchanger tubes to be supported. Preferably, openings or passages 74 have an inner dimension prior to exposure of the tube sheet 70 to the system heat exchange medium slightly greater than the outer dimension of the heat exchanger tubes therein.

Tube support sheet 70 includes a pair of sheet-

like parts

80, 82 each provided with a plurality of axially aligned open-ended extensions or

protrusions

84, 85 respectively. Expansible members 90 are positioned between

parts

80, 82 respectively opposite each of the

protrusions

84, 85.

Parts

80, 82, having expansible members 90 therebetween, are preferably fastened together to form a unitary structure by a suitable adhesive or bonding material 104. Expansible members 90 are each provided with an opening 95 therethrough coaxial with and having a dimension, before expansion of member 90, substantially equal to the dimension of the openings defined by

protrusions

84, 85 respectively. Each pair of axially aligned open-ended

protrusions

84, 85, having an expansible member 0 disposed therebetween with opening 05 therethrough cooperate to form each of the tube receiving openings or passages 74. As noted heretofore, the dimension of tube receiving openings or passages 74 prior to exposure of tube sheet 70 to the system refrigerant is preferably slighty greater than the outer dimension of the heat exchanger tubes.

Expansible members 90 are formed from a suitable material adapted to swell or expand on exposure to the system refrigerant. Preferably, expansible members 90 each comprise a ring-like element having a generally T- shape when viewed in cross section with opposite circumferential locking surfaces 92, 93. Each expansible member 90 is held or trapped between sheet-

like parts

80, 82 through engagement of locking

surfaces

92, 93 thereof with the terminal areas of

protrusions

84, 85 respectively. By this construction each of the ring-like expansible members 90 is held in coaxial relationship with its associated protrusions 84, S5 to form an uninterrupted tube receiving opening or passage 74. While expansible members 90 are disclosed as substantially ring-shaped having a crosssectional form resembling a T, other suitable shapes and/ or cross-sectional configurations therefor may be conteniplated.

Sheet-

like parts

80, 82 with expansible members 90 therebetween define a space which is substantially filled by a suitable relatively rigid material 104 adapted to channel or funnel the expansion or swelling of members 90, when exposed to the system refrigerant, radially inward into tight engagement with the outer peripheral portion of the heat exchanger tubes. In a preferred embodiment of the invention, filler material 104 also serves to fasten or bond sheet-

like parts

80, 82 together with expansible members 90 trapped between each pair of

protrusions

84, 85 to form a unitary tube support sheet 70. A preferred filler material for bonding sheet-

like parts

80, 82 together comprises a suitable thermosetting resin. Other suitable means for fastening or otherwise securing sheet-

like parts

80, 82 together may be contemplated.

Sheet-

like parts

80, 82 are formed from a suitable rigid material such as metal, thermoplastic sheet stock, or thermosetting resin. Where

parts

80, 82 are formed from a thermosetting resin, suitable reinforcing means such as metallic wire or thread, glass fiber thread, or chopped and randomly oriented glass fiber particles may he formed integrally therewith to enhance the rigidity of

parts

80, 82.

Parts

80, 82 are preferably curved or bevelled at 83 to minimize chipping of the support sheet 70 during insertion of the heat exchanger tubes therethrough.

As noted heretofore, expansible members 90 are comprised of a suitable elastomeric material adapted when exposed to the system refrigerant to swell or expand. A composition adapted to expand in the presence of monofluorotrichloromethane (CCl F), commonly known as refrigerant R-ll, is shown in the following example (in parts by weight):

2-chloro-1,3-butadiene 100 Stearic acid 0.5 Magnesium oxide 2 Carbon black Zinc oxide 5 Z-mercaptoimidazoline 0.5

An example of a composition adapted to swell when exposed to a lithium bromide (LiBr) solution, useful in absorption refrigeration systems, is as follows (in parts by weight):

In assembly of heat exchanger 20, tube support sheets or baffies 70 may be fixedly positioned in compartment 41 by suitable means (not shown) with tube openings 74 therein in axial alignment with respective pairs of

tube sheet openings

60, 61.

Tube sheet openings

60, 61 and tube support sheet openings 74 preferably have a dimension slightly greater than the outer dimension of the heat exchanger tubes 22 whereby positioning of the heat exchanger tubes 22 in

openings

60, 61 and 74 is facilitated.

Each of the heat exchanger tubes 22 is passed through a tube sheet opening 60 or 61 through each of the tube support sheet openings '74 axially aligned therewith into the opposite tube sheet opening 60 or 61. The end portions of each of the heat exchanger tubes 22 may be thereafter expanded by suitable means (not shown) into tight engagement with that part of

tube sheets

42, 43 defining

openings

60, 61 respectively. On exposure to the system refrigerant, for example, when the system is charged with refrigerant, expansible members in tube support sheets 70 expand or swell to tightly grip that portion of the outer periphery of the heat exchanger tube 22 opposite thereto. As noted heretofore, the closely surrounding relatively rigid filler or bonding material 104 channels expansion of each of the members 90 radially inward. By this arrangement, each heat exchanger tube is securely held against movement relative to the tube support sheet.

Subsequent purging of refrigerant from the system causes expansible members 90 to contract thereby freeing the heat exchanger tubes for movement relative to the tube support sheets. Disengagement of heat exchanger tube end portions from

tube sheets

42, 43 permits withdrawal of the tube from the heat exchanger.

While applicants novel tube support structure is described in connection with the system heat exchanger 20, it is appreciated that heat exchanger 2 may be similarly constructed.

Referring particularly to FIGURE 4 of the drawings, applicants novel tube support sheet may be formed by placing one of the paired sheet-like parts 80 in assembly fixture with open-ended protrusions 84 thereof facing outwardly. An expansible member 90 may be then placed on each of the protrusions 84. Locking surfaces 92 of member 90 fit over the ends of protrusion 84 to hold expansible members 90 on each of the protrusions 84 with opening 95 therethrough coaxial with the opening defined by the protrusion 94. Sheet-like part 82 may be then placed in fixture 100 opposite part 80 by inserting the ends of protrusions 85 in a corresponding locking surface 93 of expansible members 90 whereby each of the openings defined by protrusions 85 is coaxial with an associated opening defined by protrusions 84 of sheet-like part 80.

The assembly may be held by suitable fastening means 108 in fixture 180. Fixture 101) may be provided with a gate 102 at the base thereof adapted to communicate with the space defined by sheet-

like parts

80, 82 and the outer surfaces of expansible members 90 trapped therebetween with a source of filler or bonding material, preferably thermosetting resin in the liquid state. Riser 106 is provided at the top of fixture 100 to permit the egress of air from the space. Additionally, riser 106 serves to indicate complete filling of the space between

parts

80, 82 and members 90. On the completion of the filling cycle as indicated by the presence of thermosetting resin in riser 106, the flow of liquid resin is interrupted. The liquid resin in the space between

parts

80, 82 and members 90 may be thereafter cured. At the completion of the curing cycle, the assembled tube support sheet 70 is removed from fixture 100.

If desired, the thermosetting resin injected into the space between

parts

80, 82 and members 90 may be in the form of a froth adapted to polymerize into a rigid cellular structure upon curing. Alternately, the thermosetting resin may comprise a suitable liquid compound which upon injection into the cavity 104 foams and polymerizes into a cellular structure.

Applicants unique tube support sheet construction permits the use of tube receiving openings having a dimension greater than the outer dimension of the heat exchanger tubes whereby heat exchanger assembly is facilitated while providing a tube support structure for the heat exchanger tubes operable during heat exchanger use to tightly grip the outer periphery of the heat exchanger tubes whereby vibration and sag of the heat exchanger tubes is obviated.

While I have shown a preferred embodiment of the invention, it will be obvious that other modifications therein may be made without departing from the scope of the invention as limited only by the following claims.

I claim:

1. In a structure for supporting tubes of a heat exchanger in predetermined spaced relationship one with another, the combination of: spaced first and second members each having openings therethrough, each of said openings in said first member being in axial alignment with a corresponding opening in said second member to thereby define plural tube receiving passageways dimensioned to freely receive a tube therethrough; expansible means arranged between said first and second members adjacent each of said tube receiving passageways, each of said expansible means forming a wall portion of the tube receiving passageway associated therewith said expansible means comprising an elastomeric material which expands when exposed to heat exchange medium, said expansible means material being substantially unaffected by temperature conditions of said heat exchange medium; and relatively rigid fastening means for securing said first member to said second member with said expansible means therebetween, said fastening means encompassing the outer periphery of said expansible means and filling the space between said first and second members so that on exposure of said expansible means to said heat exchange medium and concurrent expansion of said expansible means, said expansible means wall portion tightly grips the tube in each of said passageways.

2. A structure for supporting heat exchanger tubes according to claim 1 in which said first and second members comprise thermoplastic material.

3. A structure for supporting heat exchanger tubes according to claim 1 in which said fastening means comprises a thermosetting resin.

4. A structure for supporting heat exchanger tubes according to claim 1 in which said first and second members comprise a thermosetting resin.

5. Tube support structure as recited in claim 1, wherein said expansible means comprises a ring-like element having an inner dimension substantially equal to the dimension of said first and second member tube receiving openings, each of said ring-like elements being coaxial with its associated tube opening.

6. A tube support sheet structure for use with heat exchange apparatus of the type having a plurality of heat exchanger tubes comprising a first sheet-like member having a plurality of open-ended protrusions terminating in a first plane spaced from said first member, each of said protrusions defining an opening having a dimension greater than the outer dimension of said heat exchanger tubes, a second sheet-like member having a like number of openended protrusions terminating in a second plane between said second member and said first plane, each of. said second member protrusions being coaxial with one of said first member protrusions and defining an opening having a dimension substantially equal to the dimension of the opening defined by said first member protrusions, an element comprised of an elastomeric material which expands upon exposure to heat exchange medium disposed between each of said first and second member protrusions and having an opening therethrough with a dimension before exposure of said element to heat exchange medium substantially equal to the dimension of the opening defined by said first member protrusion and coaxial therewith, said elastomeric material being substantially unaffected by temperatu-re conditions of said heat exchange medium, and bonding means between said first and second members, said bonding means encasing the outer periphery of said expansible elements.

7. A tube support sheet according to claim 6 in which said bonding means comprises a thermosetting resin material.

8. A tube support sheet according to claim 7 in which said first and second members comprise a thermosetting resin material.

9. A tube support sheet according to claim 7 in which said first and second members comprise a metallic material.

10. A tube support sheet according to claim 7 in which said first and second members comprise a thermoplastic material.

11. A tube support sheet according to claim 7 in which each of said expansible elements comprise a ring-like structure having a first part including the inner periphery thereof in the space between said first and second planes and a second part including the outer periphery thereof between said first member and said first plane and said second member and said second plane.

References Cited UNITED STATES PATENTS 2,310,927 2/1943 Bay 285--213 X 2,550,560 4/1951 Heron s- 285-3824 X 2,859,948 11/1958 Callard -178 X 2,989,784 6/1961 Aamodt 264263 3,088,555 5/1963 Karlgaard 18888 3,117,174 1/1964 Hessinger et al 264-263 3,186,294 6/1965 Williamson 202173 3,187,810 6/1965 Helin et al. 165158 3,191,674 6/1965 Richardson 165-458 ROBERT A. OLEARY, Primary Examiner.

FREDERICK L. MATTESON, JR., Examiner.

A. W. DAVIS, Assistant Examiner.

Claims

1. IN A STRUCTURE FOR SUPPORTING TUBES OF A HEAT EXCHANGER IN PREDETERMINED SPACED RELATIONSHIP ONE WITH ANOTHER, THE COMBINATION OF: SPACED FIRST AND SECOND MEMBERS EACH HAVING OPENINGS THERETHROUGH, EACH OF SAID OPENINGS IN SAID FIRST MEMBER BEING IN AXIAL ALIGNMENT WITH A CORRESPONDING OPENING IN SAID SECOND MEMBER TO THEREBY DEFINE PLURAL TUBE RECEIVING PASSAGEWAYS DIMENSIONED TO FREELY RECEIVE A TUBE THERETHROUGH; EXPANSIBLE MEANS ARRANGED BETWEEN SAID FIRST AND SECOND MEMBERS ADJACENT EACH OF SAID TUBE RECEIVING PASSAGEWAYS, EACH OF SAID EXPANSIBLE MEANS FORMING A WALL PORTION OF THE TUBE RECEIVING PASSAGEWAY ASSOCIATED THEREWITH, SAID EXPANSIBLE MEANS COMPRISING AN ELASTOMERIC MATERIAL WHICH EXPANDS WHEN EXPOSED TO HEAT EXCHANGE MEDIUM, SAID EXPANSIBLE MEANS MATERIAL BEING SUBSTANTIALLY UNAFFECTED BY TEMPERATURE CONDITIONS OF SAID HEAT EXCHANGE MEDIUM; AND RELATIVELY RIGID FASTENING MEANS FOR SECURING SAID FIRST MEMBER TO SAID SECOND MEMBER WITH SAID EXPANSIBLE MEANS THEREBETWEEN, SAID FASTENING MEANS ENCOMPASSING THE OUTER PERIPHERY OF SAID EXPANSIBLE MEANS AND FILLING THE SPACE BETWEEN SAID FIRST AND SECOND MEMBERS SO THAT ON EXPOSURE OF SAID EXPANSIBLE MEANS TO SAID HEAT EXCHANGE MEDIUM AND CONCURRENT EXPANSION OF SAID EXPANSIBLE MEANS, SAID EXPANSIBLE MEANS WALL PORTION TIGHTLY GRIPS THE TUBE IN EACH OF SAID PASSAGEWAYS.