AU752390B2

AU752390B2 - A heat exchanger

Info

Publication number: AU752390B2
Application number: AU20788/99A
Authority: AU
Inventors: Russell Anthony Clarges
Original assignee: DAIRY ENGINEERING PRODUCTS AND; MALCOLM GUY BAILEY; Tyco New Zealand Ltd
Current assignee: DAIRY ENGINEERING PRODUCTS AND SERVICES Ltd; Tyco New Zealand Ltd
Priority date: 1998-01-23
Filing date: 1999-01-20
Publication date: 2002-09-19
Anticipated expiration: 2019-01-20
Also published as: WO1999037965A1; AU2078899A; EP1055095A4; EP1055095A1

Description

WO 99/37965 PCT/NZ99/00005 1 A HEAT EXCHANGER BACKGROUND OF THE INVENTION This invention relates to a heat exchanger and more particularly a direct expansion contact heat exchanger.

With direct expansion contact heat exchangers it is difficult to maintain hygiene standards. Problems can also arise with flow control and the heat exchanger can be inefficient. The main difficulty associated with hygiene arises from the inability of the heat exchanger to be readily disassembled for cleaning and/or inspection.

SUMMARY OF THE INVENTION The object of the present invention is to provide a direct expansion contact heat exchanger which is of such construction that it can be readily disassembled for cleaning and/or inspection.

Broadly, in one aspect of the invention there is provided a direct expansion contact heat exchanger including a plurality of inter-connected overlapping heat exchange elements removably located within a housing, said housing having inlet and outlet means to enable, in use, flow of fluid through the housing between adjacent overlapping heat exchange elements, the heat exchange elements being connectable via heat WO 99/37965 PCT/NZ99/00005 2 exchange medium inlet and outlet means to heat exchange medium.

In a preferred form of the invention, the heat exchange elements are of substantially disc shape with a sector thereof removed. In the preferred form the housing is of tubular construction with an internal diameter just greater than the external diameter of the heat exchange elements. In the preferred form of the invention, the inlet and outlet means are located at opposite ends of the housing and extend transverse to the central longitudinal axis of the housing.

The housing can be provided with end covers, plates or the like.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a sectioned elevation view of a preferred form of the heat exchanger according to the invention, Figure 2 is a sectioned elevation view of a bank of heat exchange elements, Figure 3 is an end view on line A-A, Figure 4 is an elevation view in the direction of arrow C as shown in Figure 2, Figure 5 is an end view on line B-B, WO 99/37965 PCT/NZ99/00005 3 Figure 6 is a face and edge view respectively of one disc element of a heat exchange element, and Figure 7 is a view similar to Figure 6 but showing the other disc element of a heat exchange element.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the preferred form of the invention as illustrated and described herein, the direct contact heat exchanger 10 as shown in Figure 1 comprises a tubular housing 11 in which a heat exchange bank 12 of overlapping heat exchange elements 14 is removably located. As shown in Figure 1, the crosssectional diameter of the elements 14 is just slightly less than the internal diameter of the tubular housing 11.

Projecting in a diametrically opposite manner from opposite ends of the housing 11 are an inlet 15 and an outlet 16 having a coupling C for coupling to a conduit through which fluid to be heated/cooled can flow. The inlet and outlet and 16 therefore extend substantially transverse to the central longitudinal axis of the housing 11.

The ends of the housing 11 are closed by closure plates, covers or the like 17 and 17' As will hereinafter be described, the heat exchange bank comprises a plurality of inter-connected heat exchange discs 14. The heat exchange disc 14 adjacent end closure 17' is coupled to an inlet conduit 18 through which heat exchange WO 99/37965 PCT/NZ99/00005 4 medium can pass into the heat exchange bank. The heat exchange disc at the opposite end of the bank 12 is connected to a return conduit 19 which extends longitudinally back through the housing 11 to exit at 19' through end plate 17'.

At least one, but preferably both end plates 17 and 17' are mounted for removal from the housing 11. Thus, with couplings (not shown) connected with conduits 18 and 19 demounted the end covers 17 and 17' can be removed to permit the heat exchange bank 12 to be slid out of the housing 11.

Consequently, the end covers 17 and 17' and the interior of the housing 11 can be cleaned and/or inspected.

Likewise, the heat exchange bank 12 can be cleaned and inspected after removal.

The heat exchange bank 12 is comprised of a plurality of separate heat exchange elements 14, each of which is formed by the joining of two dish shaped disc elements 20 and 21 (see Figures 6 and Each disc element 20 and 21 is of generally circular shape but with a sector removed to form a straight edge 22. The disc elements 20 and 21 are provided with a plurality of dimples 23 in a conventional manner.

As can more clearly be seen in the cross-sectioned side views forming parts of Figures 6 and 7, each disc element 20 and 21 is of shallow disc shape by having inwardly turned edge portions 24.

WO 99/37965 PCT/NZ99/00005 Disc element 20 has an opening in which a stub tube 25 is mounted. Thus, when the disc elements 20 and 21 are joined together, tube 25 is located diametrically opposed from an opening 26 of disc element 21, this opening 24 being formed as part of a dome or turret 28.

In the preferred form of the invention as illustrated, each disc element 20 and 21 is provided with a cut-out 27 in the periphery substantially opposite to the straight portion 22.

This provides a clearance for the return conduit 19.

The disc elements 20 and 21 are joined about their peripheral edges, ie the peripheral edges of the inclined portions 24 by welding or any other suitable means. The thus formed heat exchange elements 14 are joined together as shown in Figures 1, 2 and 4 by a tubular projection 25 of disc 20 of one element 14 engaging into the turret opening 26 of the disc 21 of the next adjacent element 14.

As can be seen more clearly in Figures 2, 3 and 5, the heat exchange elements 14 when so disposed have the straight edges 22 at diametrically opposed sides of the heat exchange bank 12. The clearance between the straight edge 22 and the internal peripheral wall surface of the housing 11 provides a clearance or flow passage for the flow of the fluid to undergo heat exchange thereby ensuring that product flowing in through inlet 15 passes over the leading heat exchange element 14 to then pass between that and the next adjacent heat exchange element and so on until it flows out through outlet 16.

WO 99/37965 PCT/NZ99/00005 6 According to the present invention therefore there is provided a direct contact heat exchanger which is of a simple yet effective and efficient constructions with a heat exchange bank which can be readily removed from a housing for inspection and/or cleaning. The direct contact heat exchanger is thus particularly suitable for use in the food industry as hygiene issues associated with such an industry can be readily addressed.

It is envisaged that a bank of heat exchange elements 14 in any particular size housing may be a single bank or a number of banks joined end to end.

The invention provides a heat exchanger which provides maximum surface area for its overall size and therefore has good efficiency characteristics. The heat exchanger according to the present invention is thus particularly suited for use in the in-line cooling of milk into a milk holding vat in a farm situation. However, the use of the heat exchanger is not restricted to this sole purpose.

The amount of overlap of adjacent elements 14 can vary as can the spacing between the adjacent heat exchange elements.

Furthermore, the position of the return line 19 can vary depending on requirements. While in the illustrated form the return line 19 passes along the outside edge of the heat exchange bank 12 it could equally pass back through the discs as a consequence of aligned openings through the discs.

WO 99/37965 PCT/NZ990005 Other modifications will be apparent to those skilled in the art and fall within the scope of the present invention.

Claims

1. A direct expansion contact heat exchanger including a plurality of inter-connected overlapping heat exchange elements (14) removably located within a housing (11), said housing (11) having inlet and outlet means (15 and 16) to enable, in use, flow of fluid through the housing (11) between adjacent overlapping heat exchange elements the heat exchange elements being connectable via heat exchange medium inlet and outlet means (18 and 19) to heat exchange medium.

2. A heat exchanger as claimed in claim 1 wherein the heat exchange elements (14) are of substantially disc shape with a sector thereof removed.

3. A heat exchanger as claimed in claim 1 or 2 wherein the housing (11) is of tubular construction and has an internal diameter just greater than the external diameter of the heat exchange element (14).

4. A heat exchanger as claimed in any one of the preceding claims wherein the inlet and outlet means (15 and 16) are located at opposition ends (17 and 17') of the housing (11) and extend transverse to the central longitudinal axis of the housing (11). A heat exchanger as claimed in claim 4 wherein the housing (11) is provided with end closures (17 and 17'). PCT/NZ99/00005 Received 01 November 1999 9

6. A heat exchanger as claimed in claim 1 wherein a heat exchange element (14) located adjacent first wall (17) of the housing (11) is coupled to a said heat exchange medium inlet means (18)

7. A heat exchanger as claimed in claim 6 wherein a heat exchange element (14) located adjacent a second end wall of the housing (11) is coupled to a said heat exchange medium outlet means (19)

8. A heat exchanger as claimed in claim 7 wherein the heat exchange medium outlet means (19) extends within the housing (11) to communicate outside the housing (11) via the first end wall (17).

9. A heat exchanger as claimed in claim 8 wherein the heat exchange medium outlet means (19) extends through clearances (27) formed in the heat exchange elements (14) A heat exchanger as claimed in claim 2 wherein each heat exchange element (14) is formed by the joining at the peripheral edges thereof two opposed dish shaped disc elements (20 and 21).

11. A heat exchanger as claimed in claim 10 wherein the disc elements (20 and 21) are dimpled.

12. A heat exchanger as claimed in claim 10 wherein one disc element (20) of a heat exchanger element (14) is provided with a tubular element (25) and the other disc Srii: WO 99/37965 PCT/NZ99/00005 element (21) is provided with an opening (26) into which the tubular element (25) of a said one disc element of an adjacent heat exchanger element (14) can engage.

13. A heat exchanger as claimed in claim 12 wherein the opening (26) in the other disc element (21) is formed in a turret or domed portion (28)

14. A heat exchanger as claimed in claim 2 wherein that part of a heat exchanger element (14) with the sector removed is located to a side of the housing (11) substantially opposite to that of the next adjacent heat exchanger element (14) or elements (14)

15. A heat exchanger bank comprising two or more heat exchangers (10) as claimed in any one of claims 1 to 14 joined together.