Fin array for use in a centrifugal fan

A heat exchanger including an array of tubes and fins is configured to reside in a centrifugal fan enabling the centrifugal fan to operate as a cooling and or heating source.

TECHNICAL FIELD

The present invention relates to heat exchangers used in a centrifugal fan operable in cooling or heating systems.

BACKGROUND OF INVENTION

A centrifugal fan also referred to as a blower fan or squirrel-cage fan is a mechanical device which brings a fluid, frequently air, into an inlet surrounding the axis of a fan wheel. The wheel forces the air out into the fan housing, creating increased pressure in the air. The air then exits though an outlet on the fan housing. Centrifugal fans have numerous applications including heating and cooling systems, and more specifically including swamp coolers. While centrifugal fans are common, compact solutions using a centrifugal fan as a heating, cooling, and/or refrigeration source are not.

SUMMARY OF THE INVENTION

As set forth in the detailed description, in accordance with various aspects of the present invention, devices and systems for heating and cooling with a centrifugal fan is disclosed. A device in accordance with the present invention generally comprises a tube and fin array in a centrifugal fan configured to operate as a heating, cooling, and/or refrigeration source.

In one embodiment, a centrifugal fan may comprise tubes and fins configured to exchange heat with air being moved by the fan. The tubes and fins may form a portion of the outer housing of the centrifugal fan. The fins may extend into the path of the air flow. The fins may be parallel with the air flow.

In another embodiment, a heat exchanger for use in a centrifugal fan may have, a housing, a fan wheel, an air entrance, and an air exit. The heat exchanger may comprise a plurality of tubes and a plurality of fins forming a shape similar to an exterior housing of the centrifugal fan. The plurality of tubes may be on an outside edge of the fins following the shape similar to an outer wall of the housing. An inside edge of the plurality of fins may be configured to substantially follow an outer circumferential profile of the fan wheel.

In another embodiment, a fin array for use in a centrifugal fan may have a housing and a fan wheel. The array may comprise a first tube, a second tube, and a fin. The fin may have a first end and a second end. The first tube and the second tube may be in parallel contact with the fin along most of the fin's length. The fin may be sandwiched between the first tube and the second tube. The fin, first tube, and the second tube may be substantially annular about an axis of the fan wheel. The first tube and the second tube may be biased toward an edge of the fin farthest from the centrifugal fan wheel.

Further objects and advantages will become apparent as the following description proceeds and the features of novelty which characterize this invention will be out pointed with particularity in the claims annexed to and forming a part of this specification.

DETAILED DESCRIPTION

The detailed description herein makes use of various exemplary embodiments to assist in disclosing the present invention. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that modifications of structures, arrangements, applications, proportions, elements, materials, or components used in the practice of the instant invention, in addition to those not specifically recited, can be varied or otherwise particularly adapted to specific environments, manufacturing specifications, design parameters or other operating requirements without departing from the scope of the present invention and are intended to be included in this disclosure. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation.

In accordance with an aspect of the present invention, a centrifugal fan may be configured as a heating or cooling system for a fluid such as air. While all fluids understood by a person of ordinary skill in the art to be operable with a centrifugal fan are contemplated herein, air is described as one particular example throughout. In accordance with an embodiment of the present invention, the centrifugal fan may include a heat exchanger that is configured to heat or cool air passing through the centrifugal fan. For example, the heat exchanger may run a fluid colder than the air pulled into the centrifugal fan, allowing the air to lose its heat to the colder fluid. In another example, the heat exchanger may run a fluid warmer than the air pulled into the centrifugal fan allowing the air pulled into the centrifugal fan to absorb the heat from the warmer fluid in the heat exchanger. In another example, the heat exchanger may be configured to operate separate tubes within the heat exchanger independently. For example, the heat exchanger may run multiple fluids simultaneously throughout the heat exchanger. The heat exchanger may also be configured to operate various tubes in multiple cycles. For example, the heat exchanger may run cold fluid in one cycle then warm fluid in a second cycle. The heat exchanger may also be configured to operate separate tubes independently while operating multiple cycles. For example, the heat exchanger may run both warm and cold fluids at the same time. The decision to run warm fluid, cold fluid, or both may be based on the desire to control various factors. The factors may include temperature, humidity, and/or ice buildup. In another example, the multiple fluids may include different types of fluids such as a refrigerant (e.g. R404), water, air, and/or any fluid recognized as beneficial by one of ordinary skill in the art. The heat exchanger may allow different types of fluids to be run at different temperatures and different physical states. For example, liquid refrigerant may be used in conjunction with gaseous water (i.e. steam). As the heat exchanger may be configured to operate separate tubes independently in multiple cycles, any combination of fluids run under any combination of different physical parameters is contemplated herein.

In accordance with an aspect of the present invention, the heat exchanger in the centrifugal fan may be a fin and tube array comprising one or more fins and one or more tubes. In accordance with an exemplary embodiment, at least one fin and tube may be in parallel contact along a signification portion of the fin's length. For example, the fin and tube may be in parallel contact along 50% or more of the fins length. In accordance with various embodiments, the fin may be sandwiched between the two tubes. The fins may extend into the path of the air flow, configured such that the fins are parallel with the air flow coming out of the fan wheel. In this position, the fins and the tubes may be substantially annular about an axis of the fan wheel, meaning the axis of the fan wheel is perpendicular to the plane defined by the larger surface (i.e. the surface with the greatest surface area) of the fins. The tubes may be biased toward the fin edge which is farthest from the centrifugal fan wheel.

In accordance with various embodiments, the one or more fins in the array may be perpendicular to and wrap around a portion of an axis of a centrifugal fan wheel. The outside of the array may approximate the shape of the housing of the centrifugal fan. The array may form part of or all of the outer housing of the centrifugal fan. For example, the fins and tubes may be stacked in an arrangement such that the fins and tubes form a contiguous outer wall of the centrifugal fan. In one example, the array may be manufactured by extruding the fins and tubes in a curved shape approximating a portion of the outer wall of the centrifugal fan.

In one example, the array may comprise a plurality of fins and tubes stacked in a continuing pattern of tube, fin, tube, fin. The continuing pattern may begin with either the tube or the fin. In accordance with the aspects and embodiments discussed above, each tube on either side of the fin may contain a different type and/or physical state of fluid.

In accordance with various embodiments of the present invention, the array may be configured such that the one or more fins occupy a space between an exterior of the centrifugal fan wheel and the centrifugal fan housing. In one example, the fan wheel may not be centered in the housing and in response the fin may be narrow on one end and progressively widens to the second end. Similarly the space between the housing and the wheel may be a different dimension than the height of the opening; accordingly, the fin may be dimensioned so it substantially fills each space, resulting in a changing height of the fin. In one example, the height of the second end of the fin may be substantial the same height as the vertical height of the exit of the centrifugal fan housing. In various embodiments, the fin height at the exit may be less than the full height of the exit but greater than half the height of the exit. Alternatively in other embodiments, the fin height at the exit may be less than half the height of the exit.

In accordance with an aspect of the invention, the array may be plumbed such that it is configured to operate the separate tubes independently and/or operate the separate tubes in multiple cycles. In accordance with one embodiment, the array may be configured with a switching flow. In a switching flow, a fluid may flow through at least one tube in different direction in response to different cycles. For example, in a first cycle the fluid may flow from a first end to a second end of a tube. In a second cycle the fluid may flow from the second end to the first end of the tube. In accordance with another embodiment, the array may be configured with an opposing flow. In an opposing flow, fluid may flow through a first tube in the opposite direction as compared to fluid flowing in a second tube. In accordance with another embodiment, the array may be configured with an alternating flow. In an alternating flow, fluid may flow in one tube in one cycle then in the next tube in a different cycle. In accordance with another embodiment, the array may be configured to operate in accordance with one or more of an alternating flow, an opposing flow, and a switching flow.

In accordance with another embodiment, the array may be plumbed such that each tube may run more than one fluid. For example, a tube may have a three way valve prior to entry into the arrays. The three way valve may switch fluid sources operating in the tube. In one example, one line connecting into the array tube may be a cooled refrigerant coming from the throttling valve (or similar step in the refrigeration process), whereas the second line connecting into the array tube may be a heated refrigerant coming from a compressor (or similar step in the refrigeration process). Thus refrigerant from multiple steps in the refrigeration process can be routed through the array. In various embodiments, liquids from different sources such as water and refrigerant may be routed through the array tube via the three way valve. While many embodiments are discussed using a three way valve, any fluid switching system that accomplishes a similar purpose is contemplated herein.

In accordance with various embodiments, the array may be incorporated into a refrigeration system as an evaporator. As shown in the attachedFIGS. 1 through 7, the present invention provides a squirrel cage evaporator having a centrifugal fan wheel12with alternating refrigerant cooling coils14,15encircling and comprising the outside diameter of the centrifugal fan wheel12. The centrifugal fan wheel12includes an electric motor13having many mounting characteristics known in the art. As shown inFIG. 2, fins17divide each of the reversing flow refrigerant evaporator coils14,15. This configuration is such that cooling fins17separating coils14,15increases the service area of evaporator thereby allowing evaporator to be partially frozen in the direction of the refrigerant flow, which will defrost on a reverse cycle in every other tube as described in more detail below.

In accordance with one exemplary embodiment, of the invention, as shown inFIG. 7, a liquid line19leaves a condenser80having a filter-drier and sight glass all known in the art and supplying a metering device25at which point the liquid converts to a gas known in the art as “flashing”. Liquid line19continues to a reversing valve26supplying flow in opposite directions through a plurality of diffusers27to supply each evaporator coil14,15with its own supply of refrigerant.

In more detail, squirrel cage evaporator with its opposing flow of refrigerant when applied to an evaporative cooler70known in the art adds to the cooling capabilities of said cooler70by dehumidifying the air passing over partially freezing evaporative coils14,15. With evaporative coils14,15freezing in alternating directions a frost pattern will alternate between one set of coils allowing the other set of coils not supplied to defrost. The condensing water, known in the art as condensate, moves along the radius forced by the velocity of the air to exit fins17and is directed via conduit28to a tank76of the evaporative cooler70thereby providing a large portion of the humidity as condensation to tank76.

In a cooling embodiment, as air is blown over fin17, heat is removed from evaporative coils14,15via convective cooling. The present invention is suitable for use with many refrigerants, including but not limited to, R404 refrigerant which has a −40° F. expansion point. When evaporator reaches the end of a pre-determined cycle of circulating refrigerant, ice starts to accumulate on the evaporator coils14, for example. Reversing valve26switches flow to evaporative coils15thereby beginning to circulate refrigerant in the opposite direction of coils14. At the next end of the pre-determined cycle, reversing valve26switches flow direction again to provide refrigerant to coils14again. By cycling the flow of refrigerant between coils14,15, the evaporative coils15,14are allowed to thaw and therefore any accumulation of ice is prevented. This is an example of the switching flow described above.

Evaporative coils14,15are parallel to one another and, preferably, made of metal though those skilled in the art will recognize that other materials may be suitable for use. In the metal embodiment, coils14,15and fins17are made of aluminum. Furthermore, fins and coils may comprise any suitable materials. In the preferred embodiment, evaporative coils14,15are in contact with fins17separating each coil14from an adjoining coil15. In the presently preferred embodiment, reversing valve26which is also known as a three way solenoid, is utilized to achieve the alternating flow.

Turning now toFIGS. 7-9, an evaporative cooler70is shown which employs an exemplary embodiment of the present invention. As shown, evaporative cooler70provides a box like housing72having an evaporative pad74comprising one side thereof. Evaporative pad74is generally a wet cardboard material which allows air to pass therethrough. As the air passes therethrough, it evaporates some of the water in pad74and is thusly cooled. To keep pad74moist, the bottom of housing70forms a tank76which is filled with water, which is pumped by a water pump75through pipe77to the top of unit70to flow down the pad74.

Squirrel cage fan12of the present invention is mounted within housing70. The air output side of fan12extends downwardly through the bottom of housing70. Squirrel cage evaporator fan12, when operating, pulls air through pad74cooling and dehumidifying the air downwardly through the output side.

In an exemplary embodiment, and with reference toFIGS. 7 and 9, the suction side of evaporator coils14,15are joined at fitting78and hence to the suction side of a compressor23. From that point, compressor23condenses the refrigerant and sends it through an inlet82to condenser80mounted on top of housing70in liquid line19. In the preferred embodiment, as best seen inFIG. 9, condenser80is in the shape of a spiral with an inlet82on the outer edge of the spiral down liquid line19from the center of the spiral positioned just above squirrel cage fan12.

In one exemplary embodiment, condensed water from the coils will drip into tank76thereby providing indeterminate amount of “calcium free” water to the reservoir at the bottom of the evaporative cooler providing for a cleaner environment and longer life set of filter pads. In another exemplary embodiment, tubing77from a water pump75pumps reservoir water into the middle of the spiral of condenser80. The water runs along condenser80opposite the refrigerant flow in liquid line19thereby providing further cooling of the refrigerant contained therein before encountering pad74where it drops down the front of pad74for cooling purposes.

In accordance with various embodiments of the invention, and illustrated inFIG. 12, tube/fin array100may be configured as a single assembly comprising one or more fins17, contacting tube14and tube15. The profile of the fins and tubes may be exaggerated in the figures, e.g.,FIGS. 12 and 13. The fins may be any width/thickness suitable to transfer energy between tubes14/15and the air passing through the fins. A plurality of tubes and fins may be included in the array functioning similarly to fin17, tube14, and tube15as discussed herein. In accordance with various embodiments of the invention, and as illustrated inFIG. 13, tube/fin array100may be a inserted into the interior of the centrifugal fan. WhileFIG. 13is shown with the centrifugal fan having outside surface131, the system may be operated without the centrifugal fan having an outside surface. Instead, the outside surface of array100may function as the outside surface of the centrifugal fan. In either embodiment, array100may be located around fan wheel12allowing air to be forced from fan wheel12into the fins17along tubes14and15and out of the centrifugal fan outlet135. As illustrated inFIG. 14, the centrifugal fan may be enclosed or partially enclosed, with tube/fin array100being located on the interior of the centrifugal fan shell. Tubes14and15and fins17may are shown through the open fan outlet135.

In accordance with various embodiments of the invention, and illustrated inFIG. 15, tube/fin array100may be plumbed with a switching flow. In one example, array100may be connected to valves152and153on each of array100's first end156and second end155. Valves152and153may be connected to valve151. Valves152and153may also exit fluid away from the array. In one instance, fluid may enter valve151. Valve151may be configured to direct the fluid to either valve152or valve153. If directed to valve152, the fluid enters valve152and is directed into first end156of array100and then out second end155of array100. The fluid then proceeds to valve153which may direct the fluid away from array100to fluid out2. In a second instance, the system may be switched such that the fluid flows through the array in the other direction. For example, valve151may direct fluid to valve153. Valve153may direct fluid into second end155of array100. The fluid may exit array100at first end156and proceed to valve152. Valve152may then direct fluid away from array100to fluid out1. While this is only one example of switching flow, all systems for providing switching flow available to a person of ordinary skill in the art are contemplated herein.

In accordance with various embodiments of the invention, and illustrated inFIG. 16, array100may be plumbed with an opposing flow. In one example, first tube14of array100may be connected at a first end162to a fluid outlet. First tube14may be connected at a second end161to a fluid inlet. Second tube15of array100may be connected at a first end163to a fluid inlet. Second tube15may be connected at a second end164to fluid outlet. In this configuration fluid flowing through tube14flows in the opposite direction of fluid flowing through tube15. While this is only one example of opposing flow, all systems for providing opposing flow available to a person of ordinary skill in the art are contemplated herein.

In accordance with various embodiments of the invention, and illustrated inFIG. 17, tube/fin array100may be plumbed with an alternating flow. In one example, first tube14of array100may be connected at a first end to valve171. First tube14may be connected at a second end to valve172. Second tube15may be connected at a first end to valve171. Second tube15may be connected at a first end to valve172. In this configuration fluid may enter valve171and be directed to either tube14or tube15. In one instance, the fluid is directed to tube14by valve171. The fluid may exit tube14at valve172and be directed to the fluid outlet. In a second instance, the fluid may be directed from “fluid in” to tube15by valve171. The fluid may exit tube15at valve172and be directed to the fluid outlet. In this configuration fluid may alternate between two tubes. While this is only one example of alternating flow, all systems for providing alternating flow available to a person of ordinary skill in the art are contemplated herein.

In accordance with various embodiments of the invention, and illustrated inFIG. 18, tube/fin array100may be plumbed with multiple fluids. For example, a first fluid source may be connected to tube14. The fluid may enter tube14on a first end and exit on a second end. Similarly, a second fluid source may be connected to tube15. In this configuration a tube array may run multiple fluids. The fluid may enter tube15on a first end and exit on a second end. While this is only one example of multiple fluids, all systems for providing multiple fluids available to a person of ordinary skill in the art are contemplated herein.

As discussed herein, the fin and tube array may be configured to operate in accordance with one or more of an alternating flow, an opposing flow, and a switching flow. As there are numerous combinations of these three configurations multiplied by various implementations of each, all possible combinations are not discussed and illustrated herein, Suffice it to say that based on the drawings and description provided herein, one of ordinary skill in the art can implement the various combinations and implementations.

Various principles of the present invention have been described in exemplary embodiments. However, many combinations and modifications of the above-described structures, arrangements, proportions, elements, materials, and components, used in the practice of the invention, in addition to those not specifically described, can be varied without departing from those principles. Various embodiments have been described as comprising automatic processes, but this process may be performed manually without departing from the scope of the present invention. Furthermore, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the invention. The scope of the invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural and functional equivalents to the elements of the above-described exemplary embodiments that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Further, a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.