Title: APPARATUS FOR EXCHANGING ENERGY AND MASS BETWEEN

FLUID STREAMS

[0001] The section headings used herein are for organizational purposes only and are not to be construed as limiting the claims in any way.

Field of the invention

[0002] The present invention relates generally to a method and apparatus for exchanging energy and mass between at least two fluid streams.

Background of the invention

[0003] The following paragraphs are not an admission that anything discussed in them is prior art or part of the knowledge of persons skilled in the art.

[0004] A conventional regenerative device that exchanges sensible heat, latent heat, and moisture between two streams of fluids can be manufactured in the form of a wheel, and can be referred to as an enthalpy wheel, an energy wheel, or a heat exchange wheel (hereinafter 'energy wheel'). Conventional energy wheels are illustrated in U.S. Pat. Nos. 4,093,435, 4,924,934 and 6,155,334.

[0005] A conventional enthalpy wheel typically rotates on a shaft at fairly low speeds, for example, no more than about 40 r.p.m (revolutions per minute). The energy wheel typically has a housing containing a matrix of media (capable of absorbing sensible heat) that is coated with a desiccant material (capable of absorbing moisture and thus latent as well as sensible heat). The media can be made of alternate sheets of flat and corrugated paper whose open-ended corrugations provide a multitude of parallel passages through the wheel in an axial direction. This arrangement of the corrugations facilitates the flow of fluids through the energy wheel. The housing together with the media is generally rotated about the shaft by, for example, a motor.

[0006] Two fluid streams, for example, a first humidified and heated air stream and a second dry and cool air stream, can enter the energy wheel along the axial direction. The first air stream flows through the energy wheel from one side into an area of the media where the humidity and heat in the air stream is absorbed and retained by the media. The second air stream flows through the energy wheel, generally through the opposite side from the first air stream, and into an area of the media that is usually in symmetrical relation to the area where the first stream entered the housing. As the energy wheel rotates about its axis, the area of the media that has retained and absorbed the humidity and heat from the first air stream rotates to where the second air stream flows through the housing to transfer humidity and heat to the dry cool air of the second stream.

Introduction

[0007] The following introduction is intended to introduce the reader to this specification but not to define any invention. One or more inventions may reside in a combination or sub-combination of the apparatus elements or method steps described below or in other parts of this document. The inventor does not waive or disclaim his rights to any invention or inventions disclosed in this specification merely by not describing such other invention or inventions in the claims.

[0008] According to an aspect of an embodiment of the invention there is provided a regenerative energy and/or mass exchange assembly, comprising: an exchange media; a central housing encompassing at least a portion of the exchange media; a first end housing connected to one end of the exchange media and one end of the central housing, the first end housing having fluid stream diverting chambers arranged to provide a fluid flow passage from a first inlet of the first end housing to the exchange media, and provide a fluid flow passage from the exchange media to a first outlet of the first end housing and a second end housing connected to another end of the exchange media and one end of the central housing, the second end housing having fluid stream diverting chambers arranged

to provide a fluid flow passage from a second inlet of the second end housing to the exchange media, and provide a fluid flow passage from the exchange media to a second outlet of the second end housing.

[0009] The first end housing has a skirt portion extending generally parallel to a central axis of the first end housing and the second end housing has a skirt portion extending generally parallel to a central axis of the second end housing.

[0010] The skirt portions provide sealing surfaces for sealing between the first end housing and the central housing and between the second end housing and the central housing. [0011] The exchange media is rotated by a motor via a shaft, and wherein the shaft is fastened to a recess arranged in a side surface of the exchange media by a drive transfer means.

[0012] A rotation sensor may be arranged on the central housing to read indications generated by a rotation impulse means arranged on or towards an outer surface of the exchange media. The rotation sensor may be a Hall effect sensor and the rotation impulse means may be a magnet. Alternatively, the rotation sensor may be a reed switch and the rotation impulse means may be a magnet.

[0013] Other aspects and features of the present invention will become apparent, to those ordinarily skilled in the art, upon review of the following description of the specific embodiments of the invention.

Brief description of the drawings

[0014] For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, which illustrate aspects of embodiments of the present invention and in which:

[0015] Figure 1A shows a perspective view of a conventional energy wheel;

-A-

[0016] Figure 1B shows a perspective view of an exchange media used in a conventional energy wheel;

[0017] Figure 2A is a longitudinal sectional view of an energy wheel assembly according to the present invention; [0018] Figure 2B is a perspective view of an energy wheel according to the present invention;

[0019] Figure 3A is a perspective detail view of a shaft according to an embodiment of the invention, using a pin to transfer force from the shaft to the heat and mass exchange media and before the pin is inserted into the pinhole; [0020] Figure 3B is a perspective detail view of a shaft according to Figure

3A after the pin is inserted into the pinhole;

[0021] Figure 3C is a perspective detail view of a shaft according to an embodiment of the invention, using a slab to transfer force from the shaft to the heat and mass exchange media and before the slab is inserted into the slot; [0022] Figure 3D is a perspective detail view of a shaft according to Figure

3C after the slab is inserted into the slot;

[0023] Figure 3E is a perspective detail view of a shaft according to an embodiment of the invention, using a pin key to transfer force from the shaft to the heat and mass exchange media and before the pin key is inserted into the hole; [0024] Figure 3F is a side detail view of a shaft according to Figure 3E;

[0025] Figure 3G is a perspective detail view of a shaft according to Figure

3E after the pin key is inserted into the hole;

[0026] Figure 3H is a side detail view of a shaft and its force transfer arrangement to the heat and mass exchange media according to an embodiment of the invention;

[0027] Figure 3I is a plan view of the force transfer arrangement of Figure

3H;

[0028] Figure 3J is a side view of a shaft end shape according to an embodiment of the invention;

[0029] Figure 3K is an end view of the shaft end shape of Figure 3J;

[0030] Figure 3L is a side view of a shaft end shape according to a further embodiment of the invention;

[0031] Figure 3M is an end view of the shaft end shape of Figure 3L;

[0032] Figure 4 is a further perspective view of an energy wheel according to the present invention;

[0033] Figure 5 is a partially exploded perspective view of an energy wheel according to the present invention;

[0034] Figure 6 is a detail view of one embodiment of an energy wheel as shown in Figure 2;

[0035] Figure 7 is a detail view of an alternative embodiment of an energy wheel to what is shown in Figure 6; [0036] Figure 8 is a detail view of an alternative embodiment of an energy wheel to what is shown in Figure 6;

[0037] Figure 9A is a perspective view of a first insert assembly for insertion into the central housing of energy wheel assembly according to the present invention; [0038] Figure 9B is a perspective view of a second insert assembly for insertion into the central housing of energy wheel according to the present invention;

[0039] Figure 9C is a perspective view of an end housing of Figures 2A and

2B according to a first embodiment; [0040] Figure 9D is a perspective view of an end housing of Figures 2A and

2B according to a second embodiment; and

[0041] Figure 10 is a perspective view of the end housing of Figure 9C and an exchange media according to an alternative embodiment.

Detailed description

[0042] Various apparatuses or methods will be described below to provide an example of an embodiment of each claimed invention. No embodiment described below limits any claimed invention and any claimed invention may cover apparatuses or methods that are not described below. The claimed inventions are not limited to apparatuses or methods having all of the features of any one apparatus or method described below or to features common to multiple or all of the apparatuses described below. It is possible that an apparatus or method described below is not an embodiment of any claimed invention. The applicants, inventors and owners reserve all rights in any invention disclosed in an apparatus or method described below that is not claimed in this document and do not abandon, disclaim or dedicate to the public any such invention by its disclosure in this document

[0043] A conventional energy wheel 50 is illustrated in FIG. 1a. Energy wheel 50 rotates on a shaft 102, at fairly low speeds, for example, no more than about 40 r.p.m. The energy wheel 50 typically has a housing 101 containing a matrix of media 103 (capable of absorbing sensible heat) that may be coated with a desiccant material (capable of absorbing moisture and thus latent as well as sensible heat). As shown in FIG. 1b, the media 103 may be made of alternate sheets of flat and corrugated paper whose open-ended corrugations provide a multitude of parallel passages through the wheel in an axial direction. This arrangement of the corrugations facilitates the flow of fluids through the energy wheel 50. The housing 101 together with the media 103 is generally rotated about the shaft 102 by, for example, a motor 104. A groove 105 can be provided on the circumference of the housing 101 so that a belt 106 can be placed within the groove 105 to transmit the driving force from the motor 104 to rotate the housing 101 of the energy wheel 50. A cassette housing (not shown) may enclose the energy wheel 50, and may be fluidly connected to gas ducts (not shown).

[0044] Two fluid streams, for example, a first humidified and heated air stream 11 and a second dry and cool air stream 21 , may enter the energy wheel 50 along the axial direction. The first air stream 11 flows through the energy wheel 50 from one side into an area of the media 103 — indicated at 15 — where the humidity and heat in the first air stream 11 is absorbed and retained by the media 103. The second air stream 21 flows through the energy wheel 50, generally through the opposite side from the first air stream 11 , and into an area of the media 103 — indicated at 25 — that is usually in symmetrical relation to the area where the first stream 11 entered the media 103. As the housing 101 of the energy wheel 50 rotates about its axis, the area of the media 103 that has retained and absorbed the humidity and heat from the first air stream 11 rotates to where the second air stream 21 flows through the media 103 transferring humidity and heat to the dry cool air of the second stream 21.

[0045] FIG. 2A shows a longitudinal sectional view of an energy wheel assembly 100 according to various embodiments of the present invention. Figure 2B is a perspective view of an energy wheel 100 of FIG. 2A. By way of example, the embodiment disclosed will refer to an exchange of heat and humidity between two gas streams such as, for example, in a ventilation or air conditioning system. However, it is understood that the energy wheel 100 can be used to exchange energy and/or mass between more than two fluid streams. More specifically, the energy wheel assembly 100 might also have applicability to other uses, such as, but are not limited to, gas purification, gas enrichment, valuable component recovery from gas mixtures, and selective mass transfer between two gas streams.

[0046] Referring to FIG. 2A and FIG. 2B, the energy wheel assembly 100 comprises a central housing 120, a first end housing 140 and a second end housing 140'. The central housing 120 is preferably cylindrical in shape and contains an exchange media 110. A suitable exchange media comprises random oriented fiber based carbon paper commercially available from E-TEK, or carbon cloth commercially available from W. L. Gore. The media 110 has two end surfaces 112, 112'. The two end housings 140, 140' are placed at the opposite open ends of the central housing 120.

[0047] The shaft 175 extends throughout the first end housing 140, preferably along the center of the annular section of the housing, and is securely fastened to the exchange media 110, or at least engages it to transfer rotational drive, so that a rotation of the shaft 175 will impart an equivalent rotation of the exchange media. The rotational movement is provided, for example, by a motor 300 via a coupling 185.

[0048] The housings 140, 140' can, initially, be identical, so that as to avoid the cost of two separate molds. The housings 140, 140' include a sleeve 124 for a bearing that, as shown for the housing 140', is closed off by a removable closure 125. This closure 125 is removed in the housing 140' to accommodate a shaft 175. The shaft 175 is mounted in bearings 126, although for some applications, the coefficient of friction between the housing material and the shaft 125 may permit the bearings to be omitted.

[0049] A first fluid stream diverting chamber 200 is formed inside the first end housing 140, by external walls 130 of the first end housing 140. Further, a second fluid stream diverting chamber 205 is formed inside the first end housing 140, by external walls 135 of the first end housing 140. The first fluid stream diverting chamber 200 has a reactivation air inlet 210 and the second fluid stream diverting chamber 205 has a dry air outlet 215. Thus, the first and second fluid stream diverter chambers 200, 205, respectively and the first end housing 140 in the embodiment disclosed cooperate with one another to form at least two flow paths to the exchange media 110 for the external gas streams. The second end housing 140' similarly has a third fluid stream diverting chamber 200' formed inside the second end housing 140', by external walls 130' of the second end housing 140' and a fourth fluid stream diverting chamber 205' formed inside the second end housing 140', by external walls 135' of the second end housing 140'. The third fluid stream diverting chamber 200' has a process air inlet 210' and the fourth fluid stream diverting chamber 205' has a wet air outlet 215'. Thus, the third and fourth fluid stream diverter chambers 200', 205', respectively and the second end housing 140' in the embodiment disclosed cooperate with one another to form at least two flow paths to the exchange media 110 for the external gas streams.

[0050] Referring to FIG. 2A and FIG. 2B (as well as Figures 4 to 5), the heat and mass exchange media 110 is disposed within the central housing 120 and rotatably movable via the shaft 175. Shaft 175 is provided with pinhole 183. The heat and mass exchange media 110 is fixedly held with respect to the shaft by means of a pin 350 that fits into the pinhole183. As is shown in Figures 3H and 3I ₁ the pin, inserted into the pinhole 183, may be lodged into a corresponding recess 184 arranged in the heat and mass exchange media 110 when the energy wheel is assembled. Therefore, the pin acts as a drive dog and the exchange media rotates in the same phase as the shaft 175. A recess 115 may be arranged in the exchange media 110 to provide clearance for the shaft 175 as the shaft engages the exchange media.

[0051] Alternative embodiments of the power transfer from the shaft 175 to the heat and mass exchange media 110 is shown in Figures 3A to 3G and 3J to 3M. [0052] Figures 3A and 3B show a detail of the shaft 175 with the pin 350 and the pinhole 183 as described earlier. Figure 3A shows the pin before it is inserted into the pinhole and Figure 3B shows the pin after it has been inserted into the pinhole.

[0053] Figures 3C and 3D show a detail of the shaft 175 and an alternative embodiment of power transfer using a sheet or disc shaped slab 351 which is insertable into a corresponding slit 186 arranged in the shaft 175. The recess 184 arranged in the heat and mass exchange media 110 will be shaped to cooperate with the shape of the slab in this embodiment of the invention. Figure 3C shows the slab before it is inserted into the slot and Figure 3D shows the slab after it has been inserted into the slit.

[0054] Figures 3E to 3G show a detail of the shaft 175 and a further alternative embodiment of power transfer using a pin-shaped key 352 which is insertable into a corresponding non-trough hole 187 arranged in the shaft 175. The recess 184 arranged in the heat and mass exchange media 110 will be shaped to cooperate with the shape of the key in this embodiment of the invention. Figures 3E and 3F show the key before it is inserted into the slot and Figure 3G shows the

key after it has been inserted into the hole. Other shapes of keys and corresponding hole may also be used, for example discs or slabs.

[0055] Figures 3J to 3M show a detail of the shaft 175 having a shaped end portion 176 arranged to correspond and cooperate with a recess 115 in the heat and exchange media 110 to provide the necessary torque transfer from the shaft to the media. Examples of different cross sectional shapes useful for the end portion are flat step (as shown in Figures 3J and 3K) or hexagonal (as shown in Figures 2L and 3M). Further shapes are considered such as triangular, oval rectangular or square (not shown). [0056] Preferably, the exchange media is held along its two end peripheries between outer rings 118 to provide added rigidity to the exchange media. Further, the outer rings 118 are attached to inner rings 119 by diametrically arranged radial arms or brackets 121. At least the inner ring 119 arranged adjacent the first end housing 140 has a through hole 122 to provide passage for the shaft 175, and conveniently to minimize the number of different components, both inner rings 119 have the through hole 122. The through hole 122 may be arranged around a central longitudinal axis of the exchange media 110.

[0057] The rings 118 are arranged to extend at least partially into annular slots 123 of each end housing 140, 140'. The rings 118 and these annular slots are dimensioned for sliding engagement, to provide a seal at either end of the exchange media 110, thereby to reduce the tendency of any flow to by-pass the exchange media 110 and mix with another flow. The first and second end housings 140, 140' are positioned such that the first fluid stream diverting chamber 200 of the first end housing 140 is generally in alignment with the second fluid stream diverting chamber 200' of the second end housing 140'.

[0058] As best shown in Figures 6, 7 and 8, the rings 118 may be spaced from the annular slots 12, to accommodate dimensional changes caused by temperature and changes in the amount of moisture absorbed in the exchange media 110.

[0059] The inner rings 119, on the other hand, are provided with a closer fit in corresponding bores in each housing 140, 140'. The inner rings 119 then serve two functions: firstly, to act as bearings supporting the exchange media 110, thereby avoiding the need for a separate through shaft and bearings; and secondly also to provide a sealing function.

[0060] The first end housing 140 and the second end housing 140' are advantageously sealingly attached to the central housing 120 using seals 150, for example o-rings or similar sealing devices. Figures 6 to 8 show details of the sealing arrangement according to further different embodiments of the invention (one embodiment being shown in Figure 2A). See further descriptions below.

[0061] The assembly comprising the first end housing 140 and the second end housing 140' with the central housing 120 disposed between them, and the central housing containing the exchange media 110, are preferably fastened together as a unit using tie rods 160 and nuts 170. Each tie rod 160 is arranged in a tie rod hole 180 provided in a fastening flange 190 arranged on the first end housing 140 as well as on the second end housing 140'.

[0062] The provision of two separate end housings 140, 140' has advantages, but may not always be essential. The separate end housings 140, 140' enable a separate central housing 120 to be provided, and this in turn enables the central housing 120 to be formed of a different material. Commonly, the central housing 120 can be formed from metal, e.g. aluminum, with the more complex structures of the end housing 140, 140' being formed by molding in plastic. As mentioned, the entire assembly is then held together with tie rods, etc.

[0063] To simplify the overall constructions, it is possible that one of the end houses 140, 140' can be integral with the central housing 120. Thus, the central housing 120 can be formed together with the respective end housing 140, 140'.

[0064] As is shown in Figure 2A, the first end housing 140 according to one embodiment of the invention further has a skirt portion 145 arranged to provide a sealing surface for the seals 150. The skirt portion extends in a direction towards the second end housing 140' of the energy wheel assembly 100. The skirt portion

further imparts a much improved strength to the first end housing 140', especially a greatly enhanced resistance to bending forces (twisting or torque forces), without the use of thick material for the end housing construction. This is beneficial for the total weight of the energy wheel assembly 100, but also provides a deeper sealing seat. Further, the end housing may be produced as a one-piece unit as opposed to being assembled from several pieces as has been the case for conventional energy wheel end housing parts. The end housing may be produced using plastic materials as opposed to metallic materials (especially aluminum), which reduces housing weight and corrosion problems. Similarly, the second end housing 140' has a skirt portion 145' corresponding to the skirt portion 145 of the first end housing 140.

[0065] A lip 146 of the respective end housing 140, 140' may be provided to, together with the skirt portion 145, form a slot for receiving the ends of the central housing 120. The inner lip is arranged generally parallel to the skirt portion and is of shorter length than the skirt. When using seals 150 sealing against the skirt portion, the inner lip is optional.

[0066] Figures 6 to 8 show alternative embodiments of sealing compared to the embodiment shown in Figure 2. In Figure 6, the seals 150 are arranged to seal against the lip 146. The seals are thus arranged on an inner surface of the central housing 120. In Figure 7, the seals are again arranged to seal against the lip 146, but the lip is arranged radially outward of the energy wheel assembly compared to the skirt portion 145 of the respective end housing 140, 140'. In Figure 8, the seals 150 are arranged to seal against an end surface 147 of the respective end housings, the end surface arranged between the skirt portion 145 and the lip 146. The relative location of the skirt and the lip is either as shown in the Figure where the skirt is outside and encompassing the lip or the skirt may be arranged inside the lip (as is shown in Figure 7).

[0067] While the present invention has been described in relation to a regenerative energy and or mass exchange assembly with flow in one direction through the exchange media, other configurations are possible. For example, U.S.

Patent 6,780,227 discloses an exchange apparatus in which a double-pass

transfer arrangement is provided. In this arrangement, the inlet and outlet ports are all provided at one end of the device. Each gas flow then starts at that one end of the device, passes through the exchange media to an end chamber, turns through 180 degrees in the end chamber, and then flows back through another portion of the exchange media. The present invention is applicable to such an arrangement with a double-pass transfer flow arrangement. In such an arrangement, all the complexity of the ports is in one end housing; the other end housing is then simplified, and essentially amounts to a plate closing off the central housing and providing a bearing for the exchange media. In this configuration, the present invention, the central housing could be formed integrally either with the end housing including all the ports or integrally with the other, simplified end housing.

[0068] To indicate the actual rotational movement of the exchange media

110, a sensing device may be used, for instance a magnetic body 250, attached to an outer surface 111 of the exchange media, and a Hall Effect sensor 255, attached to the central housing 120. The sensor may be attached to an outside or an inside surface of the housing. The magnetic body will induce a signal from the Hall Effect sensor once for each revolution of the exchange media. Naturally, a plurality of evenly spaced magnetic bodies, arranged on the exchange media, may be used to generate more than one signal per revolution. Alternative locations for the magnetic body may be the two end surfaces 112, 112' of the exchange media and the Hall Effect sensor may then be arranged inside one or more of the fluid stream diverting chambers 200, 200', 205, 205', respectively. By using multiple Hall Effect sensors (not shown), the failure of one sensor would not compromise the revolution counting function of the system. Alternatively, other types of trigger/sensor combinations may be used, for example magnet-and-reed switch or optical sensors. A less useful alternative is a mechanical sensor since it is more prone to malfunctioning during the operating conditions inside an energy wheel.

[0069] Reference is now made to FIG. 9A and FIG. 9B, which illustrate insert assemblies 310 and 312. The energy wheel assembly 100 may be adapted for use at various fluid stream flow rates. Specifically, wheel assembly 100 may be provided with inserts 310 and 312. The use of inserts 310 and 312 may be

desirable when wheel assembly 100 is operated at a lower flow rate than originally designed; the inserts have the effect of reducing the effective flow cross-section through the exchange media 110, so as to maintain flow velocities at a reasonable level and thereby to give effective heat and mass transfer. [0070] Inserts 310 and 312 may both be installed in the wheel assembly 100 at either end of the central housing 120 within the housings 140, 140'. However, for simplicity and for cost reasons, it may be sufficient to use just one insert 310 or 312 at the inlet of each stream. Further, the housings 140, 140' may be identical or similar, and this can avoid the cost of molding two different housings. [0071] Figures 9c and 9d show a variant embodiment of the housings, indicated at 140a, 140a ¹ , where the housings 140a, 140a' are the same. For reasons unrelated to the design of the energy and mass exchanger, it can be noted that each housing 140a, 140a ¹ has a pair of ports 340, 342, whose configuration is described in more detail below. It will be understood that alternative configurations of the ports can be provided.

[0072] In Figure 9c, for the housing 140, the port 340 serves as an inlet and is provided with an insert 310; the port 342 is then an outlet. For the housing 140a' Figure 9d, the port 342 is an inlet and is provided with an insert 312; the port 340 is then an outlet. [0073] Provided the inlet flow is directed to the centre of the exchange media, it has been found that there is no necessity to provide an insert 310, 312 at the outlet to control the flow. However, for some applications, it may be beneficial to seal off the outer annulus of the exchange media 110, at both ends, corresponding to the flow from the inserts 310, 312, to prevent flow of air and moisture into the outer annulus where it could become trapped.

[0074] Reference is now made to Figure 10. As an alternative to sealing off the outer annulus of the exchange media 110, the exchange media 110 may be replaced by a second exchange media 110' having a smaller radius. As shown in Figure 10, the smaller radius of such a second exchange media 110' may correspond to the internal radius of flanges of the inserts 310, 312 detailed below.

[0075] Each of the inserts 310, 312 is molded and shaped so as to fill the respective housing and to be flush with the surface of the housing facing the exchange media 110.

[0076] Referring first to Figure 9a, the insert 310 has a flange portion 314 that has and annular semicircular shape. A base portion 316 is connected to the flange portion 314. An inlet 318 extends under the flange 314, as viewed in Figure

9a and opens into a chamber 320 above the base 316, as viewed in Figure 9a. As shown at 322, to facilitate molding in plastic, a portion of the flange 314 is set back to conform to the shape of the inlet 318. Otherwise, the edge of the flange around the set back portion 322 is flush with the remainder of the flange 314, so as to form an effective seal against the exchange media 110. The flange 314 has an inner radius corresponding to that of the chamber 320.

[0077] Turning to Figure 9b, the second insert 312 is similar to the first insert

310. Thus, the second insert 312 has a flange 324 and a base 326, but is intended to function as an outlet. An outlet 328 extends generally radially, whereas the inlet 318 extends in a more tangential direction. The outlet 328 opens into a chamber 330. Again to facilitate molding, the flange 324 shows an inset or set back portion 332 above the outlet 328, as viewed in Figure 9. As for the insert 310, the flange 324 has an inner radius corresponding to that of the chamber 330. [0078] Referring to Figures 9c and 9d, these show variant profiles for the housings 140, 140', here designated 140a and 140a'. The principal difference in these housings 140a and 140a ¹ is that each includes an inlet 340 arranged to provide a generally tangential flow and an outlet 342 arranged to receive a more radial flow. The housings 140a and 140a ¹ correspond with those shown in the earlier drawings.

[0079] Thus, when assembled, inserts 310 and 312 generally form a barrier, for the inlet flows, that prevents fluid from reaching exchange media 110, except through the openings created by the chamber 320, 330 facing the exchange media. As noted, it may also be beneficial to close off the outer annulus of the exchange media 110 with epoxy or other sealing material. A first flow path exist from the inlet 318 of the insert 310 in the end housing 140 through a part of the

inner core of the exchange media 110 to port 340 of the other housing 140a ¹ ; correspondingly, from the end housing 140a ¹ , there is a second flow path extending from the respective inlet 328 in the insert 310 through another portion of the core of the exchange media 110 to the port 342 of the housing 140. [0080] The access openings created by chambers 320, 330 direct and focus the flow of fluid to a central region of the exchange media. This concentration of the flow of fluid increases flow velocity through the exchange media 110. . This can compensate for an overall reduction of the flow rate of the fluid. Without such compensation, a reduced flow rate can result in lower flow velocities that can, in turn, result in the accumulation of water in the exchange media 110 and flooding. The size of the opening or flow cross-section created by chambers 320, 330 may be adjusted to compensate for a variety of mass or volume flow rates.

[0081] While the above description provides example embodiments, it will be appreciated that the present invention is susceptible to modification and change without departing from the fair meaning and scope of the accompanying claims. Accordingly, what has been described is merely illustrative of the application of aspects of embodiments of the invention and numerous modifications and variations of the present invention are possible in light of the above teachings.