GB2296966A - Regenerative heat exchanger with reciprocating elements - Google Patents

Abstract

A regenerative heat exchanger comprises a flow path 2A-31 or 2B-31 for a heating fluid (e.g. exhaust gas from a turbine) and a second flow path 41-10A for a fluid to be heated (e.g. high pressure air). Matrix elements 4A-E are supported on a shuttle 7 which can move axially (the elements and shuttle are preferably annular). Hot fluid is passed from inlet/s 2A, 2B to outlet 31 and heat elements in the flow paths 4C-E. The fluid to be heated is passed from inlet 41 through element 4A to outlet 10A. In the position illustrated hot fluid may be supplied to inlet 2B only. The shuttle moves axially to expose different elements to the flow paths. The shuttle is caused to move by admitting high pressure gas selectively to end spaces 11, 12. Instead of heat exchange the apparatus may be used to treat a fluid by exposure to a catalyst and for regeneration of the catalyst by exposure to another fluid. The matrix elements will, in this instance, comprise a catalyst.

Description

HEAT EXCHANGER The present invention relates to a heat exchanger in the form of a regenerator and especially, but not exclusively, a regenerator for use with a gas turbine.

Several types of heat exchanger for transferring heat from a first fluid to a second fluid via a solid are well known. It is also know that for identical heat transfer performance and pressure drop, the surface area of solid material exposed to the fluids (and forming fluid passages) and thus the bulk of the solid, and consequently to some extent the cost, are directly proportional to the fluid passage size. Thus small size and high performance at relatively low cost can be achieved by heat exchangers with very small passage size and laminar, low velocity fluid flow.

However, the formation of very small fluid flow passages which allow adjacent flow of the first and second fluids whilst preventing the fluids from mixing with each other is difficult and expensive.

It is therefore recognised that for compact, high performance heat exchangers the fluids should contact the solid material at different times rather than at different positions on the solid. Thus the first fluid flows over an element of the heat exchange solid for a given period of time donating heat to the solid and, thereafter, the element is removed from the first fluid and the second fluid flows over the element for a given time, absorbing heat from the element of the heat exchange solid. Such a heat exchanger is usually known as a regenerator. Generally, the element of the heat exchange solid is alternately exposed to the first and second fluids allowing continuation of the heat exchange process. In the above described process the first fluid, which begins relatively hot and donates heat to the heat exchange solid may be referred to as the donor fluid.The second fluid, which begins relatively cool and absorbs or receives heat from the solid, may be referred to as the recipient fluid.

A major problem in regenerators is the difficulty in providing an effective means of sealing between the first and second fluids whilst still allowing the heat exchange solid to be exposed alternately to the first and second fluids. The regenerator is therefore generally restricted to applications in which there is little or no pressure difference between the fluids or where it is feasible to separate the fluids by valves.

In regenerators a high degree of effectiveness can be obtained by providing the heat exchange solid in the form of a matrix having a number of fluid flow passages extending therethrough and by flowing the first fluid through the matrix in a first direction and the second fluid through the matrix in the opposite direction.

However, in regenerators of this type the problem of effective sealing is compounded by the differential expansion of the hot and cold ends of the matrix.

Most commercial regenerators rely upon a rotary system in which a member which supports at least first and second elements of matrix is rotated from a position in which the first matrix element is exposed to the first fluid to a position in which it is exposed to the second fluid. Simultaneously, the second element of matrix is rotated from a position in which it is exposed to said second fluid to a position in which it is exposed to said first fluid. Continued rotation allows each element of matrix to be exposed, alternately to the first and second fluids. Effective sealing between the two fluids continues to be a problem in such regenerators.

A review of regenerators is given in a paper entitled "Low-Leakage and High-Flow Regenerators for Gas Turbine Engines", D G Wilson, Journal of Power and Energy of the Institution of Mechanical Engineers, Vol. 207, No.

A3. The rotary regenerator is discussed therein and some proposals for providing effective sealing are made, including the possibility of having a regenerator in which the matrix elements are rotated in an incremental fashion and clamping seals are provided which clamp to form a tight seal when rotation is not occurring, and periodically release in order to allow rotation.

It is an object of the present invention to eliminate or mitigate the problems associated with sealing between the two fluids in rotary regenerators.

According to a first aspect of the present invention there is provided a heat exchanger of the type in which a heat exchange solid is exposed to a first, donor, fluid in order to absorb heat therefrom and is then exposed to a second, recipient, fluid in order to donate heat thereto, said heat exchanger comprising: a first-fluid inlet and a first-fluid outlet with a first-fluid path therebetween; a second-fluid inlet and a second-fluid outlet with a second-fluid path therebetween; support means for supporting said heat exchange solid wherein said support means is adapted to cause said heat exchange solid to reciprocate between a first position, in which said heat exchange solid is exposed to said first fluid in said first-fluid path, and a second position, in which said heat exchange solid is exposed to said second fluid in said secondfluid path.

Preferably, sealing means comprising at least one sealing ring is provided in order to prevent leakage of one of said first and second fluids into the other of said fluids.

Preferably, said support means is bounded by inner and outer casings and said inner and outer casings are configured so that each includes a portion of said first-fluid path and a portion of said second-fluid path.

Preferably, the first-fluid inlet and the second-fluid outlet are provided in the outer casing.

Preferably, said support means comprises a shuttle having at least one cylindrical or annular surface, said surface being adapted to move adjacent a cylindrical or annular surface of a casing in which at least one fluid inlet or fluid outlet is provided, and wherein said at least one sealing ring is provided to seal between the said surface of the shuttle and the said surface of the casing.

Preferably, said shuttle has a first, internal, generally cylindrical surface adapted to move adjacent an outer generally cylindrical surface of the inner casing, and said shuttle has a second external generally cylindrical surface adapted to move adjacent an inner generally cylindrical surface of the outer casing and wherein at least one sealing ring is provided to seal between the first generally cylindrical surface of the shuttle and the outer surface of the inner casing, and at least one further sealing ring is provided in order to seal between the second surface of the shuttle and the inner surface of the outer casing.

Preferably, said at least one sealing ring comprises at least one projection mounted piston ring.

Preferably, there are provided a plurality of separate but adjacent elements of heat exchange solid and between each of said elements there is provided a separation member, each separation member being provided with a sealing ring.

Preferably, the motive power to cause reciprocation of the heat exchange solid is provided by pressurised gas.

Preferably, lubrication means is provided in order to facilitate reciprocation of the heat exchange solid, and/or to reduce wear.

Preferably, the shuttle means is provided with rotation means to prevent or reduce uneven wear of the sealing rings.

Preferably, said heat exchange solid is in the form of a matrix.

Preferably, said matrix comprises: alternate flat and corrugated plates; ceramic especially in the form of discs or honeycomb; sintered ceramic; sintered metal; wire wool; glass balls; glass wool; wound woven wire ribbon; loose metal plastic natural pebble or other balls or nodules.

According to a second aspect of the present invention there is provided a method for heat exchange between first and second fluids comprising the steps of: exposing a heat exchange solid to the first fluid; moving said heat exchange solid so as to expose it to the second fluid; and moving said heat exchange solid so as to again expose it to said first fluid; wherein said steps of moving said heat exchange solid, in combination, comprise imparting reciprocal motion to said solid.

Preferably, said first and second fluids are prevented from commingling by the provision of sealing means in the form of at least one sealing ring.

Preferably, said heat exchange solid is a matrix and exposing said matrix to said first and second fluids comprises placing said matrix in a flow path of said respective fluids and allowing said fluids to pass therethrough.

According to a third aspect of the present invention there is provided apparatus as defined above but wherein rather than being adapted for heat exchange, said apparatus is adapted for treating a first fluid by exposure to a catalyst, and for regenerating the catalyst by exposure to a second fluid and wherein, accordingly, the heat exchange solid is replaced by a matrix of catalyst.

According to a fourth aspect of the present invention there is provided a method including use of a catalyst.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which: Fig. 1 is a vertical, axial cross-section of a first embodiment of a heat exchanger in accordance with the present invention; Fig. 2 is a vertical radial cross-section along A-A as shown in Fig. 1; Fig. 3 is a vertical radial cross-section, along B-B of Fig. 1 but with the shuttle moved so that the matrix is shown in cross-section; Fig. 4 is a vertical radial cross-section of a second embodiment of a heat exchanger in accordance with the present invention; Fig. 5 is a vertical radial cross-section along C-C of Fig. 4; Fig. 6 is a vertical radial cross-section along D-D of Fig. 4 but with the shuttle moved so that the matrix is shown in cross-section;; Fig. 7 is a vertical axial cross-section of a third embodiment of a heat exchanger in accordance with the present invention.

With reference to Figs. 1 to 3 a heat exchanger in accordance with the present invention comprises an outer casing 1 defining a first-fluid inlet means in the form of annular first and second first-fluid inlets 2A, 2B adapted to allow ingress of a first, donor, fluid in the form of hot low pressure exhaust gas from a gas turbine engine. The annular first-fluid inlets 2A, 2B are fed from first-fluid pipes 2. The outer casing 1 also defines an annular second-fluid outlet 10A adapted to allow egress of a second, recipient, fluid in the form of air at high pressure. The second fluid can leave the annular outlet 10A via an outlet pipe 10.

The outer casing 1 has a generally cylindrical inner liner 3. The inner liner 3 is designed to allow the passage of fluid therethrough in the region of the first-fluid inlets 2A, 2B and the second-fluid outlet 10A, by being reduced to the form of five axial bars 3A to 3E in the regions of the inlets and outlets.

The outer casing 1 defines a generally cylindrical cavity therein. Located within the generally cylindrical cavity there is provided a support means in the form of an annular shuttle 7 which supports and carries a plurality of annular elements 4A, 4B, 4C, 4D, 4E of a heat exchange matrix. In the embodiment of Fig. 1 the matrix is formed from alternate flat and radially corrugated annular plates supported at their radially inner edges by a cylinder 6 which forms the backbone of a shuttle 7. The cylinder is not continuous but is designed with ports 5 so as to allow fluid flow therethrough in the region of the matrix elements 4A to 4E by being reduced to the form of five axial bars 6A to 6E (see Figs. 2 and 3) in the axial region of the matrix elements.The five axial bars 6A to 6E cross with four annular portions coaxially aligned with and sealed against the inside edges of four axially central ring flanges 15 (which will be described hereafter). The shapes of the alternative flat and radially corrugated discs provide a large number of small fluid passages allowing fluid to flow radially through the matrix elements 4A to 4E. The plates are compressed between six spaced apart ring flanges 15 which are separated by five spacers 16 in order to define the five matrix elements 4A to 4E. At each axial end of the adjacent matrix elements are long spacers 16A which space apart the two end ring flanges 15 from respective shuttle end flanges 15A (which are similar in construction to the ring flanges 15).The arrangement of shuttle end flanges 15A, long spacers 16A, ring flanges 15, spacers 16 and flat and radially corrugated plates is secured by five through bolts 17 which are substantially equiangularly spaced apart about the annular form of the shuttle.

The annular shuttle 7 is adapted to move axially so as to move the elements of the matrix 4A to 4E relative to the first and second first-fluid inlets 2A, 2B and the second-fluid outlet 10. Because the cylinder 6 is formed so as to allow flow of the first fluid through the shuttle only in the region of the matrix elements 4A to 4E, the first first-fluid inlet 2A is effectively shut-off when none of the matrix elements is adjacent to it (but when this is the case there are at least two matrix elements, 4D, 4E adjacent the second first-fluid inlet 2B, so flow of the first fluid is not prevented).

Similarly, the second first-fluid inlet 2B is effectively shut-off when no matrix element is adjacent to it (but when this is the case at least two matrix elements 4A, 4B will be adjacent to the first firstfluid inlet 2A).

Within the circular space defined by the inner surface of the cylinder 6 which forms the backbone of the shuttle 7 there is provided a generally cylindrical inner casing 8 which remains stationary with respect to the outer casing 1. The generally cylindrical inner casing 8 has an axially extending, diametric wall 8A along part of its length which divides said part of the inner casing into first and second discrete semicircular axially aligned channels 30, 40. The first channel 30, in use, carries the first fluid and the second channel 40, in use, carries the second fluid.

The first channel 30 is connected at one end thereof to a cylindrical first-fluid outlet portion 31 of the inner casing 8. The first channel 30 and outlet portion 31 together constitute outlet means for the first fluid. The second channel 40 is connected at one end thereof to a cylindrical second-fluid inlet portion 41 of the inner casing 8 and said second channel 40 and inlet portion 41 together constitute inlet means for the second fluid.

The inner casing 8 is provided with first to eighth axially spaced apart, outwardly extending flanges 81 to 88. The second to seventh flanges 82 to 87 extend between the cylindrical part of the inner casing 8 and the shuttle 7. Said flanges 81 to 88 define various annular portions of the apparatus therebetween.

Between the first flange 81 and the second flange 82 there is defined a first end space 11, which is also defined by part of the outer surface of the inner casing 8, by part of the liner 3 of the outer casing 1, by a first annular end plate 13, which connects the inner casing 8 to the outer casing 1, by part of the cylinder 6 and by one of the shuttle end flanges 15A.

Between the second flange 82 and the third flange 83 there is defined a first annular first-fluid flow chamber 32 which connects directly to the first channel 30 of the inner casing 8 and is separated from the second channel 40 of the inner casing 8 by the external wall of the inner casing 8. Said first-fluid flow chamber 32 may connect, via one or more of the matrix elements 4A, 4B, 4C to the first first-fluid inlet 2A, or may be isolated from the said inlet 2A by the cylinder 6, depending on the axial position of the shuttle 7. Mounted on the circumferential edge of the second flange 82 is a second-flange sealing ring 19A, preferably in the form of a piston ring of the type used in large diesel engines. The second-flange sealing ring 19A provides a seal between the second flange 82 and the cylinder 6.

The third and fourth flanges 83, 84 support a first wide sealing ring 19B, with axial width slightly larger than the axial length of each of the matrix elements.

The first wide sealing ring 19B may seal against the inner face of the cylinder 6 or against one of the inner edges of the annular parts of the cylinder 6 in the region of one of the ring flanges 15. A first annular space 38 is formed, bounded by the third and fourth flanges 83, 84, the outer wall of the inner casing 8 and the first wide ring seal 19B. This annular space is effectively a sealing space.

Between the fourth and fifth flanges 84, 85 there is formed an annular second-fluid flow chamber 9 which connects directly to the second channel 40 of the inner casing (and is separated by the wall of the inner casing 8 from the first channel 30). This annular chamber forms part of the path of the second fluid and is, throughout use, connected via one of the five matrix elements 4A to 4E to the annular second-fluid outlet lOA.

The fifth and sixth flanges 85, 86 support a second wide sealing ring 19C similar in use and construction to the first wide sealing ring 19B. A second annular space 39 is formed, bounded by the fifth and sixth flanges 85, 86, the outer wall of the inner casing 8 and the second wide sealing ring. The second annular space 39 is similar in function to the first annular space 38.

Between the sixth and seventh flanges 86, 87 is defined a second annular first-fluid flow chamber 33, analogous in function to the first annular first-fluid flow chamber 32, which connects directly to the cylindrical outlet portion 31 of the inner casing 8.

The seventh and eighth flanges 87, 88 along with a second end plate 14 (which may be an extension of the eighth flange 88 as illustrated or may be constructed analogously to the first end plate 13) one of the shuttle end plates 15A, part of the surface of the liner 3 and part of the cylinder 6, together form a second end space 12 similar in purpose and construction to the first end space 11. The seventh flange 87 is provided with a seventh-flange sealing ring 19D, similar in form to the second-flange sealing ring 19A and is adapted to seal against the cylinder 6.

At the outer circumferential side of the shuttle each of the five ring flanges 15 and each of the two end flanges 15A (which together define the axial portions of the shuttle) is provided at its outer edge with a ring seal 18. Said ring seals are preferably of the type used as piston rings in large diesel engines, and are projection mounted in grooves provided on the ring flanges 15 and end flanges 15A for the purpose.

It can thus be seen that the axially spaced apart first-fluid path and second-fluid path elements defined by the outer casing 1 (namely the first and second first-fluid inlets 2A, 2B and the annular second-fluid outlet lOA) are effectively sealed from each other at all times by the contact of the sealing rings 18 on the liner 3, and the action of the flange mounted sealing rings 19A, 19B, 19C, 19D against the cylinder 6.

Similarly, the axially spaced apart first and secondfluid path elements defined by the inner casing 8 (namely the first and second annular first-fluid flow chambers 32, 33 and the annular second-fluid outlet lOA) are sealed from each other. Although the parts of the first-fluid path may connect with each other and the parts of the second-fluid path may connect with each other by the passage of the fluids through the matrix elements it will be appreciated that the seals keep the first-fluid path and the second-fluid path separate and distinct from each other and thus prevent commingling of the first and second fluids. Thus this embodiment effectively uses sealing rings to seal the first and second fluids from each other.

In use the first fluid in the form of hot low pressure gas is supplied to the first and second first-fluid inlets 2A, 2B and passes from at least one of said inlets 2A, 2B flowing through and giving up heat to at least two elements of the matrix 4A to 4E. It then passes through ports 5, and either via the first annular first-fluid flow chamber 32 and the first channel 30 or via the second annular first-fluid flow chamber 33, to the cylindrical outer portion 31, from which it exits the regenerator as cool low pressure gas.

The second fluid, in the form of cool high pressure gas is supplied to the cylindrical inlet portion 41 of the inner casing 8 and passes through the second channel 40 of the inner casing 8 to the annular second-fluid flow chamber 9. The fluid then passes through a matrix element 4A to 4E to the annular second-fluid outlet lOA to the outlet pipe 10. The second fluid absorbs heat as it passes through the matrix and therefore enters the second-fluid outlet 10A and exits the outlet pipe 10 as hot high pressure gas.

After a given time the shuttle moves linearly and axially, exposing different matrix elements to the fluid paths, and the heat transfer process continues.

The shuttle 7 is caused to move axially by admitting high pressure gas selectively to the first and second end spaces 11, 12. It may be noted that in the illustrated embodiment at least two elements of the matrix are in the path of the first fluid at any given time and at least one element of the matrix is in the path of the second fluid at any given time.

It may also be noted that providing six matrix elements rather than five would ensure that three matrix elements are in the path of the first fluid at any given time, thus keeping resistance to flow of the first fluid more constant. This variation may be used if it is envisaged that the more constant flow is sufficiently desirable to merit the inclusion of an extra matrix element, ring flange and ring seal and the consequent extra expense.

In the embodiment of Fig. 1 the arrangement is such that, in use, each matrix element is exposed alternately to the first and second fluids. The fluids flow in opposite directions through the matrix (the first fluid flowing radially inwardly and the second fluid flowing radially outwardly) allowing high effectiveness.

A second embodiment is illustrated in Figs. 4, 5 and 6.

This embodiment is similar in design to the embodiment of Figs. 1 to 3 and for clarity and simplicity most of the reference numerals have been omitted from Figs. 4 to 6. Where reference numerals used on Figs. 4 to 6 are the same as reference numerals in Figs. 1 to 2 they are intended to identify similar features. The embodiment of Figs. 4 to 6 is suited to high temperature applications. The outer casing 1 and in particular the inner liner 3 especially in the regions of the first-fluid inlets 2A, 2B and the second-fluid outlet lOA are cooled by a coolant circulating in spaces 21 provided in the outer housing 1 for the purpose. It will be noted that the hot gases (that is the first, donor, fluid before donating heat to the matrix, and the second, recipient, fluid after receiving heat from the matrix) are to the outer side of the apparatus.This both enables cooling of the apparatus by the coolant in the outer casing 1 and enables free expansion of hot gases, which is generally desirable, although under some circumstances it might be desirable to have the hot side to the inside of the regenerator.

The sealing rings 18 and ring flanges 15 are insulated from the matrix elements 4A to 4E by insulation pads 23.

A third embodiment showing an alternative configuration is illustrated in Fig. 7 but will not be described in detail since its mode of operation is conceptually similar to that of the earlier embodiments.

Essentially first and second axially spaced apart first-fluid inlets 102A, 102B are provided in an outer casing 101 and first-fluid outlets 31A, 31B are provided in an inner casing 108 with an annular cylindrical shuttle 107, carrying four annular elements of matrix 104, located between said inner casing 108 and said outer casing 101. Axially intermediate said first-fluid inlets 102A, 102B there is provided a second fluid outlet 110 defined by the outer casing 101. Second-fluid inlet means 41 are provided and defined by the inner casing 108. The shuttle 107 reciprocates so as to expose each matrix element 104 repeatedly to the first and second fluids.

In all the embodiments lubrication would be by quills as in large diesel engine practice extending through the inner and outer casings (not shown). These could be in line with the position of the sealing rings at each end of the shuttle stroke. Lubricant injection could be timed to coincide with the end of the stroke when the rings were in line with the quills.

To avoid ridged wear of the rings the shuttle could be rotated by a small increment on each stroke by a toothed sector on one end cover and a combined end stop and indexing tooth on the shuttle.

Alternative types of matrix could, of course, be used, including matrices comprising ceramic discs, ceramic honeycomb, sintered metal honeycomb, wound woven wire ribbon, wire wool, loose metal, ceramic, plastic, natural pebble or other balls or nodules.

The sealing rings may be diesel type metal piston rings as these are freely available in sizes up to 940 mm diameter. Of course alternatives such as steam engine type piston rings, non-metallic, carbon or plastic rings or solid labyrinth rings (metal or non-metallic) could be used.

The mounting configuration of the rings could also vary, for example all the sealing rings could be mounted on parts of the shuttle (although this would require the sealing rings mounted to the inside part of the shuttle to be inward springing which whilst quite possible is likely to involve greater expense than using the more common outward springing type of sealing ring).

In the illustrated embodiments radial differential expansion could be accommodated by the sealing rings floating in their grooves. Axial expansion could be accommodated preferably by a bellows expansion joint in the second fluid inlet or by a sliding joint in the outer casing.

Clearly, there is a great deal of scope for alternative designs in accordance with the present invention, not all of which may require an annular shuttle with fluid paths from the inside to the outside thereof. Also the number of matrix elements may be varied and the advantages of having a larger number of smaller elements (such as the increase in compactness due to the possibility of making the axial width of the inlets, outlets and sealing spaces smaller) must be balanced against the additional expense of having a greater number of required sealing rings.

The embodiment of Fig. 7 would be suitable for use with the Kawasaki 52A-01 turbine as detailed in the "Diesel and Gas Turbine" worldwide catalogue. By varying the size, regenerators substantially as detailed in the embodiments could be produced which are suitable for use with turbines with power outputs covering at least the range 700 - 2000 kW. Multiple units could be used up to this capacity and above. It is estimated that with a mass flow of 4.7 kg/s of each fluid the embodiment of Fig. 7 could give 90% regenerator effectiveness.Given a first fluid initial temperature of 495"C and a second fluid initial temperature of 266"C the temperature of the second, recipient, fluid could be raised to about 472"C. This is based on a matrix of alternate plain and corrugated plates with a triangular passage equivalent diameter of 0.84 mm.

Embodiments of a regenerator in accordance with the present invention could be used in other applications, for example where a first fluid is processed by a catalyst which is then regenerated by a second fluid.

In this case the heat transfer matrix would be replaced by a matrix of catalyst.

The timing of passes of the matrix across the fluid paths could of course be varied (which would vary the heat transfer performance) and the motion could be either continuous or incremental.

The described embodiments avoid the major disadvantages of previous regenerators by employing sealing rings to seal between the two fluids. Such seals are relatively easily and cheaply available and their characteristics are well known. Piston rings have been developed over two centuries to seal under many different conditions including those of high temperatures and pressures.

Modifications and improvements may be incorporated without departing from the scope of the invention.

Claims (21)

1. A heat exchanger of the type in which a heat exchange solid is exposed to a first, donor, fluid in order to absorb heat therefrom and is then exposed to a second, recipient, fluid in order to donate heat thereto, said heat exchanger comprising: a first-fluid inlet and a first-fluid outlet with a first-fluid path therebetween; a second-fluid inlet and a second-fluid outlet with a second-fluid path therebetween; support means for supporting said heat exchange solid wherein said support means is adapted to cause said heat exchange solid to reciprocate between a first position, in which said heat exchange solid is exposed to said first fluid in said first-fluid path, and a second position, in which said heat exchange solid is exposed to said second fluid in said second-fluid path.

2. A heat exchanger as claimed in Claim 1, wherein sealing means comprising at least one sealing ring is provided in order to prevent leakage of one of said first and second fluids into the other of said fluids.

3. A heat exchanger as claimed in either preceding Claim, wherein said support means is bounded by inner and outer casings and said inner and outer casings are configured so that each includes a portion of said first-fluid path and a portion of said second-fluid path.

4. A heat exchanger as claimed in Claim 3, wherein the first-fluid inlet and the second-fluid outlet are provided in the outer casing.

5. A heat exchanger as claimed in any of Claims 2, 3 or 4, wherein said support means comprises a shuttle having at least one cylindrical or annular surface, said surface being adapted to move adjacent a cylindrical or annular surface of a casing in which at least one fluid inlet or fluid outlet is provided, and wherein said at least one sealing ring is provided to seal between the said surface of the shuttle and the said surface of the casing.

6. A heat exchanger as claimed in Claim 5, when dependent upon one of Claims 3 or 4, wherein said shuttle has a first, internal, generally cylindrical surface adapted to move adjacent an outer generally cylindrical surface of the inner casing, and said shuttle has a second external generally cylindrical surface adapted to move adjacent an inner generally cylindrical surface of the outer casing and wherein at least one sealing ring is provided to seal between the first generally cylindrical surface of the shuttle and the outer surface of the inner casing, and at least one further sealing ring is provided in order to seal between the second surface of the shuttle and the inner surface of the outer casing.

7. A heat exchanger as claimed in any of Claims 2 to 6, wherein said at least one sealing ring comprises at least one projection mounted piston ring.

8. A heat exchanger as claimed in any one of Claims 2 to 7, wherein there are provided a plurality of separate but adjacent elements of heat exchange solid and between each of said elements there is provided a separation member, each separation member being provided with a sealing ring.

9. A heat exchanger as claimed in any preceding Claim, wherein the motive power to cause reciprocation of the heat exchange solid is provided by pressurised gas.

10. A heat exchanger as claimed in any preceding Claim, wherein lubrication means is provided in order to facilitate reciprocation of the heat exchange solid, and/or to reduce wear.

11. A heat exchanger as claimed in Claim 5, or any Claim dependent thereon, wherein the shuttle means is provided with rotation means to prevent or reduce uneven wear of the sealing rings.

12. A heat exchanger as claimed in any preceding Claim, wherein said heat exchange solid is in the form of a matrix.

13. A heat exchanger as claimed in Claim 12, wherein said matrix comprises: alternate flat and corrugated plates; ceramic especially in the form of discs or honeycomb; sintered ceramic; sintered metal; wire wool; glass balls; glass wool; wound woven wire ribbon; loose metal plastic natural pebble or other balls or nodules.

14. A method for heat exchange between first and second fluids comprising the steps of: exposing a heat exchange solid to the first fluid; moving said heat exchange solid so as to expose it to the second fluid; and moving said heat exchange solid so as to again expose it to said first fluid; wherein said steps of moving said heat exchange solid, in combination, comprise imparting reciprocal motion to said solid.

15. A method as claimed in Claim 14, wherein said first and second fluids are prevented from commingling by the provision of sealing means in the form of at least one sealing ring.

16. A method as claimed in either of Claims 14 or 15, wherein said heat exchange solid is a matrix and exposing said matrix to said first and second fluids comprises placing said matrix in a flow path of said respective fluids and allowing said fluids to pass therethrough.

17. A heat exchanger substantially as hereinbefore described with reference to and as shown in Figs. 1 to 3, Figs. 4 to 6 or Fig. 7.

18. A method for heat exchange substantially as hereinbefore described with reference to and as illustrated by Figs. 1 to 3, Figs. 4 to 6 or Fig. 7.

19. Apparatus as claimed in any preceding Claim, wherein rather than being adapted for heat exchange, said apparatus is adapted for treating a first fluid by exposure to a catalyst, and for regenerating the catalyst by exposure to a second fluid and wherein, accordingly, the heat exchange solid is replaced by a matrix of catalyst.

20. Treatment apparatus for use of a catalyst, substantially as hereinbefore described with reference to and as shown in Figs. 1 to 3, Figs. 4 to 6 or Fig.

7.

21. A treatment method including use of a catalyst substantially as hereinbefore described with reference to and as illustrated by Figs. 1 to 3, Figs. 4 to 6 or Fig. 7.