and are not to be construed as limiting the claims in any way.
The present invention relates generally to a method and apparatus for exchanging energy and mass between at least two fluid streams.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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:
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
A conventional energy wheel 50 is illustrated in
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.
Referring to
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.
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.
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.
Referring to
Alternative embodiments of the power transfer from the shaft 175 to the heat and mass exchange media 110 is shown in
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.
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′.
As best shown in
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.
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.
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′.
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.
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′.
As is shown in
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.
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. Pat. No. 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.
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.
Reference is now made to
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.
c and 9d show a variant embodiment of the housings, indicated at 140a, 140a′, 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′ 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.
In
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.
Reference is now made to
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.
Referring first to
Turning to
Referring to
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′; correspondingly, from the end housing 140a′, 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.
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.
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.
This application claims the benefit under 35 USC 119(e) of U.S. Provisional Application Ser. No. 60/826,154, filed Sep. 19, 2006, which is incorporated herein by reference. The section headings used herein are for organizational purposes only
Number | Date | Country | |
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60826154 | Sep 2006 | US |