WO1990010840A1

WO1990010840A1 - Heat exchange manifold

Info

Publication number: WO1990010840A1
Application number: PCT/GB1990/000364
Authority: WO
Inventors: John Brian Clarke
Original assignee: Gec-Marconi Limited; Alcan International Limited
Priority date: 1989-03-09
Filing date: 1990-03-09
Publication date: 1990-09-20
Also published as: AU5188990A; KR920700383A; GB2231650A; GB9005389D0; BR9005738A; CA2028134A1; EP0434772A1; GB8905436D0; JPH03505365A

Abstract

A manifold formed from a plurality of segments (6), each having an aperture (7) therethrough and at least one recess in a surface thereof extending between the aperture and an edge of the segment, such that, when the plurality of segments are secured together, the apertures together form a manifold chamber (13) and the recesses define between the segments flow passages (10a, 10b, 10c) opening into the chamber, and closure members (8) at each end of the chamber, a common flow passage (4) being provided between the chamber and the exterior of the manifold.

Description

Heat Exchange Manifold

The present invention relates to a manifold arrangement for use with a ulti panel heat exchanger.

The present invention is particularly suitable for use with heat exchangers and power generator systems as shown in Figure 1. This figure shows a plant which derives energy from ocean water, depending on the natural temperature difference existing at different levels in the water. Referring briefly to Figure 1, cold water is pumped from the sea bottom by pumps 1 through an inlet 2 to a heat exchanger 3 contained within a tank 3A. Working fluid, typically ammonia, is cooled and condensed in the heat exchanger 3. The fluid is then pumped by pump 4 into a second heat exchanger 5 in a different tank 5A, where it is evaporated, obtaining its latent heat from warm water which is supplied by pumps 7 from an inlet 8 close to the sea surface. The resulting ammonia gas under pressure is used to drive a turbine 9 which is connected to an electricity generator, not shown. The ammonia gas then passes back into the heat exchanger 3 where it is once again condensed by the cold water from the sea bed. The heat exchangers comprise banks of heat exchanging panels. The panels are sealed to the environment and arranged in large tanks.

In particular, the heat exchangers comprise a plurality of rollbonded heat exchange panels and it is an object of the present invention to provide a manifold which is suitable for connecting a plurality of rollbonded heat exchange panels to a common fluid path.

In accordance with a first aspect of the present invention, there is provided a heat exchanger comprising: a plurality of substantially parallel heat exchange panels each defining a passage for a working fluid terminating at an opening at an edge of the panel; and a manifold comprising a plurality of manifold elements overlapping and interleaved with the heat exchange panels and shaped to conform with the shape thereof in the overlapped region, the manifold elements being secured and sealed to each other and to the heat exchange panels and being shaped so as to form a path for the flow of working fluid to or from the said opening on each panel.

Preferably, the manifold elements comprise essentially flat plates having apertures which define said path.

The manifold typically comprises a stack of such plates provided with inter-engaging formations around the apertures; the overlapping regions of the two adjacent plates embracing a heat exchange panel at or near said opening. The plates in a stack can conveniently be held together by suitable retaining members, for example tie-bolts, which extend through locating holes in each plate. An adhesive can also be applied between the plates to assist in sealing.

In one embodiment at least one or several adjacent plates have the aperture extended to one edge thereof so as to define a passage which communicates with said path. Blanking plates can be provided for the top and bottom of the stack and blanking parties can be provided for the upper and lower limits of said passage.

Potential problems are envisaged with the condensing heat exchangers in which the working fluid is lead from the bottom of the heat exchanger after condensing. In a plant of the type described the outlet from the heat exchanger might be separated from the circulation pump by a significant distance and it may be required to route the outlet pipe upwardly over the tank side wall. In such a case, the working fluid would be subjected to reduced pressure and as the fluid may be near its boiling point. problems may occur with re-evaporation and the formation of gas-locks in the pipeline so preventing proper flow and affecting the efficiency of the heat exchanger.

In accordance with a second aspect of the present invention, there is provided a heat exchanger as defined above including a condenser comprising: a heat exchange element defining a path for a working fluid to be condensed, the element being contained in a container for a cooling fluid; and means for using pressurised working fluid to impel condensed working fluid from a bottom region of the element upwardly so as to allow it to be delivered to a region outside the container for recycling.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the drawings, wherein:-

Figure 1 shows a schematic view of a plant in which the invention can be used;

Figure 2 illustrates a plan view of one embodiment of a manifold segment;

Figure 3 illustrates a side view of Figure 2; Figure 4 illustrates a segment for forming a main inlet into the manifold cavity;

Figure 5 illustrates a perspective view of the assembled manifold from segments shown in Figures 2, 3 and 4; and

Figure 6 illustrates a longitudinal section through Figure 5 along the line XX.

Figures 7 and 8 show alternative versions of a condenser panel incorporating the second aspect of the invention; and

Figure 9 shows a schematic view of the system incorporating the condenser shown in Figures 7 and 8.

Referring to Figures 2 and 3, a manifold segment 6 is formed from a thin aluminium plate and has an aperture 7 in its centre. A rim 8 is disposed around the aperture in an open loop with both ends terminating at an edge 6a, and is either formed integrally with the segment or fixed to it at a separate fabrication stage. Raised portions 9, extending from the aperture 7 to the edge 6a between the ends of the rim 8 define, together with the rim 8, three flow passages openings 10a, 10b, and 10c, when the segment is stacked against another segment. Holes 11 enable tie bars 14 (as shown in Figure 6) to pass through several such segments 6, when they are assembled against one another. The tie rods enable the segments to be firmly secured together so as to form a leak-proof seal therebetween with the aid of sealing and/or adhesive materials.

Figure 4 shows a second type of manifold segment 21 having a cut-out 22 extending between the aperture 7 and an edge 6b opposite to the edge 6a including the flow passage 10, segments of this second type, segments when assembled together with the first type of segment as shown in Figure 5, form a common flow passage 4 (Figure 5), partly defined by the cut-outs 22, between the chamber defined by the apertures 7 together, and the exterior of the manifold. This common flow passage enables easy connection of a main supply or exhaust line to the manifold cavity 13 (Figure 5) .

Figures 5 and 6 show the assembled manifold with end plates removed. Segments 6 and 21 are arranged so as to form the common flow passage 4 into, or out of, the manifold cavity. The heat exchange panels 2 with fluid ducts 5, are positioned so as to receive a fluid entering the manifold from the common flow passage 4, used as an input port. The fluid enters in the direction of the arrow A, passes through the manifold cavity 13 and is distributed through the flow passages 10 into the ducts 5 of the heat exchange panels 2. A similar manifold is positioned at the exhaust side to receiv fluid leaving the heat exchange panels. The manifold segments are held together by way of tie rods 14 which pass through holes 11 in the manifold segments 6. Locking nuts 16 are provided at both ends of the rods 14. The manifold may be attached to the heat exchanger when assembled or built up around each individual heat exchange panel by interleaving successive segments so as to form a "sandwich". Of course a segment may have rims 8 disposed on both sides.

When varying the dimensions of heat exchange equipment, such as by varying the number of panels, the manifold dimensions are altered accordingly by adding or subtracting segments, thus saving the expense of forming custom built manifolds.

The system shown in Figure 9 comprises a circulation pump A which delivers condensed fluid via a pipe to an evaporation B in a tank C containing relatively warm water. The evaporated fluid is used to drive a turbine D and is subsequently fed to a condenser E in a tank H of relatively cold water. A jet pump F is provided at the outlet from the condenser E to drive condensed fluid back to the pump A. A separate feed line G is taken directly from the outlet of the pump A to drive the jet pump E. Figure 7 shows the condenser E comprising a heat exchange element 10 having a pathway 11 for working fluid 12 defined therein by rollbonding. A fluid delivery line 30 connects to the element 10 at an upper region thereof at an inlet 31 and the condensed working fluid leaves the element 10 at an outlet

15 provided at a lower region thereof.

The feed line G provides pressurised, condensed motive fluid directly to a jet pump 13 which is provided adjacent the outlet 15, the jet pump 13 and the outlet 15 feeding into an outlet pipe 18. The jet pump 13 comprises a nozzle

16 for motive fluid and a cavity 17 defined in the outlet pipe 18 adjacent the nozzle 16 and outlet 15.

Referring now to Figure 8, the condenser shown therein has essentially the same components as described in relation to Figure 2 above and identified by the same reference numerals with the suffix 'A'. However, in this case the heat exchange element 10A, jet pump 13A and outlet pipe 18A are formed integrally by rollbonding. In this case the feed line 14A is at least partially formed in the heat exchanger 10A by rollbonding, a separate inlet 32A being provided for connection to the line G.

In operation, both of the embodiments shown in Figures 7 and 8 function in the same manner. In each case the condenser forms part of a plant as described in relation to Figures 1 and 4, i.e. condenser 3 in tank 3A or condenser E in tank H. The working fluid is supplied from the circulation pump 4, A to the delivery line 30, 30A. The flow of working fluid 12, 12A is directed into the pathway 11, 11A in the heat exchange element 10, 10A and is condensed in the pathway 11, 11A and delivered to the outlet 15, 15A and into the outlet pipe 18, 18A. The motive fluid, which is at higher pressure than the condensing working fluid, is delivered directly to the jet pump 13, 13A from the circulation pump 4, A where it is emitted from the nozzle 16, 16A into the cavity 17, 17A. The pressure in the cavity 17, 17A is lower than in the pathway 11, 11A so condensed working fluid 12, 12A will always flow from the outlet 15, 15A. The motive fluid from the jet pump 13, 13A provides pressure to the fluid in the outlet pipe 18, 18A and serves to drive the fluid from the condenser to the circulation pump. In this manner, the formation of gas bubbles is reduced and even if bubbles do form, the action of the pump means that fluid is driven from the condenser E to the circulation pump A.

The jet pump described has the advantage that it is easily formed during the production of the condenser and requires no moving parts and is essentially maintenance free. However, other types of pumps could still be used to provide pressurised motive fluid at the outlet from the heat exchange element.

Changes can be made while remaining within the scope of the invention.

Although this aspect of the invention has been described in the particular embodiment of a heat exchanger, the invention¹ may be used in similar circumstances in, for example, process industries.

Claims

1. A heat exchanger comprising: a plurality of substantially parallel heat exchange panels each defining a passage for a working fluid terminating at an opening at an edge of the panel; and a manifold comprising a plurality of manifold elements overlapping and interleaved with the heat exchange panels and shaped to conform with the shape thereof in the overlapped region, the manifold elements being secured and sealed to each other and to the heat exchange panels and being shaped so as to form a path for the flow of working fluid to or from the said opening on each panel.

2. A heat exchanger as claimed in claim 1, wherein the manifold formed from a plurality of segments, each having an aperture therethrough and at least one recess in a surface thereof extending between the aperture and an edge of the segment, such that, when the plurality of segments are secured together, the apertures together form a manifold chamber and the recesses define between the segments flow passages opening into the chamber, and closure members at each end of the chamber, a common flow passage being provided between the chamber and the exterior of the manifold.

3. A heat exchanger as claimed in claim 1, wherein the manifold elements comprise essentially flat plates having apertures which define said path.

. A heat exchanger as claimed in claim 2, wherein at least one segment of the manifold has an opening extending between the aperture and the edge of the segment to define the common flow passage.

5. A heat exchanger as claimed in claim 4, wherein two or more segments each have an opening extending between the aperture and the edge of the segment, the openings together defining the common flow passage.

6. A heat exchanger as claimed in claim 4, wherein the or each opening is on the opposite side of the segment from the recess or recesses.

7. A heat exchanger as claimed in claim 2, wherein at least two flow passages extend from the aperture to an external edge of the manifold segments.

8. A heat exchanger as claimed in claim 2, wherein a segment of the manifold has a raised rim partly surrounding the aperture and extending, at each end thereof, to an edge of the segment to define therebetween a said recess.

9. A heat exchanger as claimed in claim 6, wherein at least one raised portion of the manifold extends from the aperture to the said edge between the ends of the raised rim to define at least two said recesses.

10. A fluid manifold formed from a plurality of segments, each having an aperture therethrough and at least one recess in a surface thereof extending between the aperture and an edge of the segment, such that, when the plurality of segments are secured together, the apertures together form a manifold chamber and the recesses define between the segments flow passages opening into the chamber, and closure members at each end of the chamber, a common flow passage being provided between the chamber and the exterior of the manifold.