Counter-rotating centrifugal blower system and fuel cell incorporating the same

Abstract

a row of blower units, each blower unit having an axial inlet and a radial outlet; an impeller disposed within the casing, the impeller drawing a gaseous medium into the axial inlet at a first pressure and discharging the gaseous medium out the radial outlet at a second, higher pressure; and a motor driving the impeller; and a duct connecting the radial outlet of at least one blower unit in the row of blower units to the axial inlet of at least one other blower unit in the row of blower units, wherein the axial inlet of at least one blower unit in the row of blower units is positioned substantially opposite the axial inlet of the at least one other blower unit in the row of blower units.

Description

[Technical Field]

[0001] The present invention relates to a centrifugal blower and a fuel cell incorporating the same. [Background technology]

[0002] Centrifugal blowers or fans are well-known devices for providing flow or movement of a gaseous medium. A common type of centrifugal blower includes a housing with an axially oriented gas inlet and a radially oriented gas outlet, an impeller disposed within the housing to draw gas into the inlet at a first pressure and expel gas from the outlet at a second, higher pressure, and a motor to drive or rotate the impeller. Variations on centrifugal blowers of this general type are disclosed, for example, in U.S. Pat. Nos. 4,917,572; 5,839,879; 6,877,954; 7,061,758; 7,351,031; 7,887,290; 7,891,942 and U.S. Patent Application Publication No. 2006 / 0051203, the entire contents of which are incorporated herein by reference.

[0003] Centrifugal blowers, in single unit and multiple unit configurations, have been disclosed as components of cooling systems for computers, servers, and other heat-generating electrical and electronic devices and equipment, see U.S. Patent Nos. 6,525,935; 7,184,265; 7,744,341; 7,802,617; 7,864,525; 7,885,068; 7,948,750; 7,902,617; and 7,885,068, the entire contents of which are incorporated herein by reference.

[0004] Centrifugal blowers of the general type described above have been disclosed as components of both polymer electrolyte membrane (PEM) and solid oxide fuel cell (SOFC) fuel cells, performing one or more functions (e.g., providing a flow of oxidant-containing gas, such as air, to the cathode element of a fuel cell assembly and / or a flow of gaseous or vaporized fuel to the anode element, recirculating unused fuel to the anode element of a fuel cell assembly, providing a cold air stream for cooling the fuel cell assembly, or providing a hot air stream for vaporizing liquid fuel prior to external or internal reforming of the fuel to provide hydrogen for operation of the fuel cell assembly). Fuel cell blower assemblies featuring one or more centrifugal blowers are described, for example, in U.S. Pat. Nos. 6,497,971; 6,830,842; 7,314,679; and 7,943,260, the entire contents of which are incorporated herein by reference.

[0005] Centrifugal blower systems including one or more centrifugal blowers have been disclosed by the present applicant. Centrifugal blower systems and fuel cell blower assemblies featuring one or more centrifugal blowers are described, for example, in U.S. Patent Nos. 9,017,893, 9,512,846, 9,593,686, and 10,273,961, U.S. Patent Application Publication No. 2018 / 00509007, and WO 2019055472, the entire contents of which are incorporated herein by reference. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 4,917,572 [Patent Document 2] U.S. Patent No. 5,839,879 [Patent Document 3] U.S. Patent No. 6,877,954 [Patent Document 4] U.S. Patent No. 7,061,758 [Patent Document 5] U.S. Patent No. 7,351,031 [Patent Document 6] U.S. Patent No. 7,887,290 [Patent Document 7] U.S. Patent No. 7,891,942 [Patent Document 8] US Patent Application Publication No. 2006 / 0051203 [Patent Document 9] U.S. Patent No. 6,525,935 [Patent Document 10] U.S. Patent No. 7,184,265 [Patent Document 11] U.S. Patent No. 7,744,341 [Patent Document 12] U.S. Patent No. 7,802,617 [Patent Document 13] U.S. Patent No. 7,864,525 [Patent Document 14] U.S. Patent No. 7,885,068 [Patent Document 15] U.S. Patent No. 7,948,750 [Patent Document 16] U.S. Patent No. 7,902,617 [Patent Document 17] U.S. Patent No. 7,885,068 [Patent Document 18] U.S. Patent No. 6,497,971 [Patent Document 19] U.S. Patent No. 6,830,842 [Patent Document 20] U.S. Patent No. 7,314,679 [Patent Document 21] U.S. Patent No. 7,943,260 [Patent Document 22] U.S. Patent No. 9,017,893 [Patent Document 23] U.S. Patent No. 9,512,846 [Patent Document 24] U.S. Patent No. 9,593,686 [Patent Document 25] U.S. Patent No. 10,273,961 [Patent Document 26] US Patent Application Publication No. 2018 / 00509007 [Patent Document 27] International Publication No. 2019055472 Summary of the Invention

[0007] [Means for solving the problem]

[0008] According to the present invention, there is provided a centrifugal blower, comprising: A row of blower units, each blower unit in the row comprising: a casing having an axial inlet and a radial outlet; an impeller disposed within the casing for drawing gaseous medium into the axial inlet at a first pressure and expelling gaseous medium from the radial outlet at a second, higher pressure; a motor for driving the impeller; and a duct connecting a radial outlet of at least one blower unit in the row of blower units to an axial inlet of at least one other blower unit in the row of blower units; Here, a centrifugal blower is provided in which the axial inlet of at least one blower unit in the row of blower units is positioned substantially opposite the axial inlet of at least one other blower unit in the row of blower units.

[0009] Furthermore, according to the present invention, 1. A fuel cell assembly comprising: a plurality of individual fuel cells, each fuel cell having an electrolyte medium, a cathode, and an anode; a fuel cell assembly including: at least one aforementioned centrifugal blower system for supplying a flow of gaseous medium to said fuel cell assembly; A fuel cell comprising:

[0010] The novel features and advantages of the centrifugal blower system described herein, having the ability to increase the pressure of the gaseous medium therein as compared to conventional centrifugal blower systems, and fuel cells incorporating such centrifugal blower systems to drive gas flow, as well as their compact deployment characteristics, will become more apparent from the following detailed description and accompanying drawings. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view of a dual blower system of the present invention. [Figure 1A] The blower unit 11 is in an inverted position in FIG. [Figure 1B] This is a centrifugal blower system with two radial outlets at 0° to each other. [Figure 1C] This is a centrifugal blower system with two radial outlets positioned at 90° to each other. [Figure 1D] This is a centrifugal blower system with two radial outlets positioned at 180° to each other. [Figure 1E] This is a centrifugal blower system with two radial outlets positioned at 270° to each other. [Figure 2] FIG. 2 is a top view of the dual blower system of FIG. 1. [Figure 3] FIG. 2 is a side view of the dual blower system of FIG. 1. [Figure 4] FIG. 2 is a side view of the air intake assembly. [Figure 5] FIG. 2 is a cutaway side view of the dual blower system of FIG. 1. [Figure 6A] FIG. 1 is a side view of the outlet of the blower in a dual blower system. [Figure 6B]FIG. 1 is a side view of the outlet of a blower with a circular flow straightener. [Figure 6C] FIG. 10 is a side view of the outlet of a blower having a flow straightener. [Figure 7A] FIG. 1 is a perspective view of the bottom of two mechanically connected dual blower systems of the present invention. [Figure 7B] FIG. 1 is a top perspective view of two mechanically connected dual blower systems of the present invention. [Figure 8A] FIG. 7B is a perspective view of the two mechanically connected dual blower systems of FIG. 7A, showing the radial outlets of said blowers directly adjacent to the radial inlets. [Figure 8B] FIG. 7C is a perspective view of two mechanically connected dual blower systems of FIG. 7B, showing the radial outlets of said blowers directly adjacent to the radial inlets. [Figure 9A] FIG. 1 is a top view of two mechanically connected dual blower systems according to the present invention. [Figure 9B] FIG. 1 is a bottom view of two mechanically connected dual blower systems according to the present invention. [Figure 10A] FIG. 9B is a perspective view of the two mechanically connected dual blower systems of FIG. 9A, showing the radial outlets of said blowers directly adjacent to the radial inlets. [Figure 10B] FIG. 9C is a perspective view of two mechanically connected dual blower systems of FIG. 9B, showing the radial outlets of said blowers directly adjacent to the radial inlets. [Figure 11] 1 is a schematic diagram of a chemical reactor including a fuel cell in accordance with the present teachings. [Figure 12A] FIG. 2 is a schematic diagram of a blower control system for a dual blower system including the dual blower system of FIG. 1. [Figure 12B] FIG. 2 is a logic flow diagram for the dual blower control system of FIG. 1. [Figure 13A] FIG. 1 is a perspective view of a tubular SOFC assembly having separate dual blower systems of the present invention for supplying air and fuel flows to the assembly. [Figure 13B]FIG. 1 is a plan view of a tubular SOFC assembly having separate dual blower systems of the present invention for supplying air and fuel flows to the assembly. [Figure 13C] FIG. 13C is a schematic diagram showing a cross section of an individual tubular fuel cell in the tubular SOFC assembly of FIGS. 13A and 13B. DETAILED DESCRIPTION OF THE INVENTION

[0012] The centrifugal blower system according to the present disclosure employs axial inlets of two different blowers arranged substantially opposite each other, e.g., the axial inlets of the two different blowers are oriented such that the gaseous medium flows into the two respective axial inlets in opposite directions. Compared to a centrifugal blower system in which the two different axial inlets are arranged in substantially the same direction, the centrifugal blower system according to the present disclosure provides several advantages. Furthermore, these advantages are further enhanced in the centrifugal blower system according to the present disclosure when the radial outlets of the two different blowers in the centrifugal blower system are arranged substantially opposite each other, e.g., when the radial outlets are oriented such that the gaseous medium flows out of the two different radial outlets in opposite directions.

[0013] It is understood that the present teachings herein are not limited to the particular procedures, materials, and modifications described, as these can vary. It is also understood that the terminology used is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present teachings, which are limited only by the appended claims.

[0014] Throughout this specification and claims, when structures, devices, apparatus, compositions, etc. are described as comprising, having, or including particular components, or methods are described as comprising, having, or including particular method steps, it is contemplated that such structures, devices, apparatus, compositions, etc. also consist essentially of or consist of the recited components, and that such methods consist essentially of or consist of the recited method steps.

[0015] In the present specification and claims, when an element or component is included in and / or selected from a list of multiple described elements or components, it is understood that the element or component can be any of the described elements or components or can be selected from a group consisting of two or more of the described elements or components. Furthermore, it is understood that the elements and / or features of the structures, devices, apparatus or compositions, or methods described herein, whether explicitly or implicitly, can be combined in various ways without departing from the spirit and scope of the present disclosure. For example, when a particular structure is referenced, that structure can be used in various embodiments of the apparatus and / or methods of the present teachings.

[0016] Use of the terms "include," "includes," "including," "have," "has," "having," "contain," "contains," or "containing," including their grammatical equivalents, should generally be understood as open-ended and open-ended, e.g., not excluding additional, unrecited elements or steps unless otherwise specified or understood from the context.

[0017] Use of the singular forms herein, e.g., "a", "an", "the", includes the plural (and vice versa) unless otherwise stated.

[0018] When the word "about" is used before a numerical value, the present disclosure includes that particular numerical value itself unless otherwise specified. As used herein, the word "about" refers to a ±10% variation from the nominal value unless otherwise specified or implied.

[0019] It should be understood that the order of steps or order for performing certain actions is immaterial so long as the present teachings remain operable. For example, methods described herein may be performed in any suitable order unless otherwise indicated or clearly contradicted by context. Further, steps may be performed simultaneously unless their nature necessitates that they be performed in that order.

[0020] In various places herein, numerical values ​​are disclosed as ranges of values. Any numerical range disclosed herein is specifically intended to include each numerical value within the range and any subrange thereof. For example, a numerical range of 0 to 20 is specifically intended to disclose 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20, as well as subranges thereof, such as 0-10, 8-16, and 16-20, respectively.

[0021] Any examples or exemplary language such as "such as" used herein are intended merely to more clearly describe the disclosure and do not limit the scope of the invention unless otherwise stated in the claims. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the present teachings.

[0022] Terms and expressions indicating spatial orientation or position, such as "upper," "lower," "top," "bottom," "horizontal," "vertical," and the like, unless the context requires otherwise, should not be construed as having any structural, functional, or operational significance herein, but merely reflect arbitrarily chosen orientations of various views of the liquid fuel CPOX reformer of the present disclosure as illustrated in some of the accompanying drawings.

[0023] The term "substantially" as used herein takes into account slight variations in the positioning of various components herein, for example, the axial inlet and / or radial outlet.

[0024] The term "opposing" as used herein may be understood to mean that various components, e.g., axial inlets, are positioned such that the flow direction of gaseous medium into one of the axial inlets of a blower unit is in an opposing direction compared to the flow direction of gaseous medium into another axial inlet of another blower unit of a centrifugal blower system described herein, although in one embodiment, the use of the term "opposing" does not encompass cases where the flow directions of gaseous medium into each axial inlet are such that the axial inlets are directly opposite each other.

[0025] The variation in arrangement, as understood herein with respect to the term "substantially" in the phrase "substantially opposed," is understood to mean, in one embodiment, that the arrangement of the axial inlets in one blower unit, when compared to the arrangement of the axial inlets of another blower unit in the row, e.g., a consecutive blower unit, is such that the two axial inlets are arranged at an angle of about 180° from each other, or allow for angular variation in location from a plane equidistant from the two axial inlets. This angle can be from 1° to about 20°, preferably from 1° to about 10°, from the plane surface. This angle can apply to the arrangement of one or both of the axial inlets.

[0026] The expression "substantially opposite each other" herein with respect to the radial outlet of one blower unit compared to the radial outlet of another blower unit in a centrifugal blower system, e.g., a consecutive blower unit in the row, is understood to be similar to that described above with respect to the axial inlet. Specifically, the two radial outlets may be disposed at an angle of approximately 180° from each other, or may be oriented with an allowance for angular variation from a plane equidistant from the two radial outlets, which angle may be between 1° and about 20°, preferably between 1° and about 10°, from the plane surface. This angle may apply to the orientation of one or both of the radial outlets.

[0027] As used herein, the expression "fuel cell" is understood to refer to a device in which an electrochemically oxidizable fuel electrochemically reacts with an oxidant to produce an oxidizing gas and a flow of electrical current.

[0028] 1 and 1A, in one embodiment of the centrifugal blower system of the present invention, a dual centrifugal blower system 10 includes a first centrifugal blower unit 11 connected to a second centrifugal blower unit 12 via a duct 13. The first blower unit 11 includes a casing 14 having an axial inlet 15 and a radial outlet 16, an impeller 17 disposed within the casing 14 for drawing a gaseous medium into the axial inlet 15 at a first pressure and discharging the gaseous medium from the radial outlet 16 at a second, higher pressure, and an electric motor 18 for driving the impeller 17. The second blower unit 12 includes a casing 19 and has an impeller 20 disposed within the casing 19 and driven by an electric motor 21, as can be seen through the view of the duct 13 in FIG. 1, and an axial inlet 22 for receiving the gaseous medium discharged from the outlet 16 of the first blower unit 11. The second blower unit further has a radial outlet 23 and an optional outlet gas flow housing 24 .

[0029] In other embodiments of the present invention shown in Figure 1 and other figures herein, arrows indicate the general direction of gas flow through the radial outlets of each blower unit in the row of blowers comprising the blower system. For example, as shown in Figure 1, the paths of the gas flow emitted from outlet 16 of first blower unit 11 and outlet 23 of second blower unit 12 are not parallel to their respective outlets but are angled relative to them. By configuring duct 13 to receive the gas flow emitted from outlet 16 while the flow remains substantially parallel to the inner walls of the duct, it is possible to prevent or reduce turbulence that may occur if the flow encounters these walls. Turbulence is advantageously minimized or avoided, reducing or eliminating turbulence as a source of backpressure within the blower system. For the same reason, it is beneficial to angle gas flow housing 24 so that its inner walls are substantially parallel to the path of the gas flow emitted from outlet 23 of second blower unit 12. The optimum shape of the inner wall of duct 13 relative to the gas flow path and the offset angle of gas flow housing 24 can be readily determined for a given gas blower system using routine experimentation. In the gas blower system shown in Figures 1-3, the inner surface (guide surface) of duct 13 and the inner surface (guide surface) of gas flow housing 24 can be inclined at an angle α of 12° to 20°, preferably 14° to 18°, relative to outlets 16 and 23.

[0030] As shown in Figure 1, the flow direction of the gaseous medium into axial inlet 15, indicated in this figure by the directional arrow to 15, which corresponds to the location of axial inlet 15 shown more clearly in the small image below this figure, is substantially opposite to the flow direction of the gaseous medium into axial inlet 22. Furthermore, in a more preferred embodiment, the orientation of outlet 16 is substantially opposite to the orientation of outlet 23, so that the flow direction of the gaseous medium discharged from outlet 16 is in a direction substantially opposite to the flow direction of the gaseous medium discharged from outlet 23.

[0031] 1-3, the duct 13 described herein has a gas flow restricting wall 25 surrounding an internal gas flow passage 26 and a gas inlet (i.e., port) 27 for introducing gas into the gas flow passage 26. The inlet 27 allows for the introduction of a different gaseous medium that is mixable with the previous gaseous medium provided through the axial inlet 15 in the duct 13.

[0032] The two gaseous media undergo initial mixing in duct 13, the extent of which depends on the degree of turbulence caused by the confluence of the two gaseous streams. This initial mixture of gaseous media in duct 13 enters second blower unit 12 where it is thoroughly mixed and a substantially homogeneous gaseous mixture is discharged through radial outlet 23 for delivery to wherever required.

[0033] The inlet 27 may be provided, for example, as one or more openings in the wall of the duct 13, or may extend beyond the wall of the duct 13 to introduce the second gaseous medium further within the gas flow path 26 of the duct 13, for example, at or near the center of the gas flow within that gas flow path 26. In the latter embodiment, the section of the inlet 27 that extends into the gas flow path 26 may have a streamlined cross-section to minimize turbulence. The section of the inlet 27 that extends into the gas flow path 26 of the duct 13 may be oriented in any suitable direction and / or orientation, for example, a direction and / or orientation that favors a more parallel, and therefore less turbulent, merging of the separate gas streams.

[0034] The centrifugal blower system embodiment of Figures 1B-1E is similar in structure to the centrifugal blower system shown in Figure 1, including the orientation of the radial outlet 23 of the second blower unit 12 relative to the radial outlet 16 of the first blower unit 11. In the blower system of Figure 1, the orientation angle is preferably approximately 180°. This angle may also be approximately 0°, 90°, or 270°. Of course, all orientation angles are contemplated, and the optimal orientation angle for a particular centrifugal blower system will depend on the specific application of the blower system.

[0035] Another angle of importance in the centrifugal blower system of the present invention is the pitch angle of the radial outlet 16 of the first blower 11 relative to the axial inlet 21 of the second blower. In the blower system embodiment shown in Figures 1-3, this angle is approximately 0°. As with the blower unit orientation angles described above, these blower pitch angles can range in value from 0° to 270°, although again, the optimum pitch value for a particular blower system will depend on the specific application requirements.

[0036] Dual centrifugal blower systems have been disclosed in which the discharge flow of a first blower is introduced into the inlet of a second blower, and each blower has approximately the same range of gas pressure and gas flow output capacity. The basic configuration of a dual blower system can be described as "1 into 2," meaning that the gas discharged from the first blower is introduced into the inlet of the second blower. However, as those skilled in the art will readily appreciate, numerous other configurations are within the scope of the present invention.

[0037] Other embodiments of the centrifugal blower systems described herein include those with three, four, or even more blower units, those in which the discharge streams from two or more blowers are introduced into the inlet of a single blower, and those in which the discharge stream of one blower is introduced into the inlet of two or more blowers. These types of blower systems are designated, for example, as "1 into 2 into 3," where the gas discharge stream of the preceding blower unit is ducted to the inlet of the next blower unit in the series. "1 and 2 into 3," for example, refers to a system in which the discharge streams of the first and second blower units are commonly ducted to the inlet of the third blower unit. "1 into 2 and 3" refers to a system in which the discharge stream of the first blower unit is ducted to the second and third blower units. In blower systems in which the gas flow of one blower unit is combined with the gas flow of another blower unit, or in which the gas flow of a single blower is split into two separate gas flows, valves may be provided to regulate the various gas flows within these systems.

[0038] In the centrifugal blower system described herein, gas discharged from each blower unit is introduced to the inlet of the subsequent blower unit through duct 13. Thus, centrifugal blower system 10 is an example of the "1 and 2 into 3" configuration described above. This configuration allows for the control of the gas flow capacity of a single relatively large blower while providing the fast response characteristics of multiple smaller blowers. An example of such a configuration is described in U.S. Pat. No. 9,512,846, the entire contents of which are incorporated herein by reference.

[0039] Centrifugal blower system 10, in which the discharge flow of one blower unit is introduced to subsequent blower units through common duct 13, is an example of a "1 into 2 and 3" arrangement of blower units. This configuration of blower units allows for more precise control of two separate gas discharge flows by using one primary gas pressure and flow supply blower and placing separate blowers downstream. An example of such an arrangement is described in U.S. Pat. No. 9,512,846.

[0040] In one embodiment, the discharge flow from a first blower unit of a triple blower system is introduced to a second blower unit through a duct 13, and the discharge flow of the second blower unit is introduced to a third blower unit through yet another duct 13. This illustrates the "1 into 2 into 3" configuration described in U.S. Pat. No. 9,512,846. This three-blower series arrangement allows the second and third blower units to quickly and accurately respond to target gas pressure and gas flow requirements, which are largely supplied by the first blower unit.

[0041] Additionally, the scope of the present invention includes centrifugal blower systems in which one or more blower units have a different gas pressure and gas flow capacity range than one or more other blower units in the system. An embodiment of such a gas blower system is shown in U.S. Pat. No. 9,512,846. For example, a dual centrifugal gas blower system includes a first blower unit with a relatively large gas pressure and gas flow capacity, the gas flow discharged from which is introduced into a smaller blower unit via duct 13. This arrangement of blowers of different sizes allows for finer control of larger gas flow rates. When a gas flow rate greater than that achievable in a blower system with roughly the same blower unit capacity is required, the larger-capacity blower unit can be supplemented with a smaller-capacity unit. This provides a wider range of gas flow rates while achieving the faster and more accurate flow control characteristics of the centrifugal blower system of the present invention.

[0042] In all of the centrifugal blower systems of the present invention, the individual blower units need not be in direct contact with one another, except for their interconnecting ducts, but may be spaced apart at some distance. Remote location of one or more blowers of the blower system of the present invention may be beneficial when optimal layout design considerations for a particular application favor such location.

[0043] The dimensions, voltage, power consumption, impeller speed, air flow rate, noise level, and other characteristics of the particular blower unit utilized in the centrifugal blower system of the present invention can vary widely depending on the gas pressure and gas flow requirements and end use. The following table provides typical characteristics of a variety of useful blower units: [Table 1] TIFF2026507392000003.tif115168

[0044] Of course, it will be recognized that the present invention is not limited to blower units having the above characteristics, but may utilize any centrifugal blower unit having smaller or larger sizes, voltage and power requirements, impeller speeds, gas pressures and gas flow capacities, etc. than those listed in the table.

[0045] 1-3, in one embodiment of the present invention, the centrifugal blower system described herein has a second higher pressure discharged from the radial outlet 16 that is higher than the second higher pressure discharged from the radial outlet of a centrifugal blower system outside the scope of the present invention, for example, a centrifugal blower system in which the axial inlet of at least one blower unit in a row of blower units is aligned in substantially the same direction as the axial inlet of at least one other blower unit in the row of blower units. The aforementioned comparison of a centrifugal blower system outside the scope of the present invention corresponds to the centrifugal blower system described herein, i.e., is the same as the centrifugal blower system described herein, except that the axial inlet of at least one blower unit in a row of blower units is aligned in substantially the same direction as the axial inlet of at least one other blower unit in the row of blower units.

[0046] Without wishing to be bound by theory, it is believed that positioning axial inlet 15 substantially opposite axial inlet 21 provides less resistance to the flow of gaseous medium within duct 13 than if the axial inlet corresponding to axial inlet 15 described herein were positioned in substantially the same direction as the axial inlet corresponding to axial inlet 21 described herein (such as the comparable axial inlet positions described in U.S. Pat. No. 9,512,846).

[0047] The second higher pressure may vary depending on various parameters of the centrifugal blower system as described herein, such as the percentage of the duty cycle of the blower system being used. In one non-limiting embodiment herein, the second higher pressure may be about 1% to about 10%, preferably about 3% to about 7%, higher than the second higher pressure in a centrifugal blower system in which the axial inlet of at least one blower unit in the row of blower units is aligned in substantially the same direction as the axial inlet of at least one other blower unit in the row of blower units.

[0048] The table below compares static pressure measurements for a centrifugal blower system with opposed axial inlets (the present invention) with a system with consistent axial inlet orientation. [Table 2]

[0049] In addition to the second, higher pressure achieved in the centrifugal blower system described herein, another advantage of the present invention is that it allows for a more compact arrangement than prior art centrifugal blower systems in which the axial inlet of one blower unit in the centrifugal blower system is aligned in substantially the same direction as the axial inlet of at least one other blower unit in the row of blower units, which can be most easily understood by viewing the present invention as shown in detail in Figures 1 and 3 of this specification.

[0050] In the embodiment shown in FIGS. 1 and 3, the first blower unit 11 has an air filter 28 on the axial inlet 15. In another embodiment (not shown), the first blower unit 11 may have an air intake assembly on the axial inlet 15, either alone or in combination with the air filter 28, as described below. In this configuration, where the axial inlet 15 of the first blower unit 11 is positioned substantially opposite the axial inlet 21 of the second blower unit 12, as shown in FIGS. 1 and 3, the placement of the air filter 28 on the axial inlet 15 results in a combined height H of the first blower unit 11 and the second blower unit 12. In contrast, in prior art inventions such as those described in U.S. Pat. No. 9,512,846, the orientation of the axial inlet of the first blower unit is substantially the same as the axial inlet of the second blower unit. That is, the inversion of the first blower unit 11 of the present invention results in a corresponding height greater than that provided by the present invention due to the presence of the air filter and / or air intake used on the first axial inlet. The present invention provides a centrifugal blower system 10 in which the axial inlet of one blower unit, e.g., a first blower unit, in the row of blower units has a height H that is less than the height of a corresponding centrifugal blower system that is arranged in substantially the same direction relative to the axial inlet of at least one other blower unit, e.g., a second blower unit, in the row of blower units.

[0051] The height H may vary depending on the parameters of the centrifugal blower system 10 described herein, but generally, the height H is 1% to 50% lower, preferably 1% to about 40% lower, and most preferably 1% to 30% lower than prior art centrifugal blower systems in which the axial inlet of one blower unit (e.g., a first blower unit) in the row of blower units is aligned in substantially the same direction as the axial inlet of at least one other blower unit (e.g., a second blower unit) in the row of blower units.

[0052] Further according to the present invention, there is provided a centrifugal blower system comprising an intake assembly, the intake assembly comprising: an air intake assembly casing having an air inlet and an air outlet, the air outlet being connectable to an axial inlet of one blower unit casing of one centrifugal blower in the row of blower units; and a check valve mounted within the air intake assembly casing and positioned to allow air to flow from the air inlet through the air intake assembly casing to the air outlet and to prevent air from flowing from the air outlet through the air intake assembly casing to the air inlet.

[0053] The air intake assembly for the centrifugal blower system described herein offers several advantages over prior art centrifugal blowers, especially when integrated into a fuel cell or fuel reformer to control the flow of gaseous media therein. The inlet air can be filtered before the check valve to filter out particulates, volatile compounds, and sulfur compounds from the environment, and can also include a desiccant to reduce moisture. The inlet air can be filtered after the check valve to filter out particulates, volatile compounds, and sulfur compounds from the environment, and can also include a desiccant to reduce moisture. The check valve prevents zero-flow conditions from backflowing from fans or other process air sources. At high temperatures, backflow can damage solid oxide fuel cells (SOFCs) and catalysts through oxidation. The present invention prevents backflow from occurring. The filter is a type of reticulated foam (with low pressure drop) that can be doped with specific materials to perform the tasks listed above. The check valve may be a flexible diaphragm made from a soft elastomer that creates little pressure drop when opening and utilizes the slight inherent stiffness and spring constant of the material to close and seal.

[0054] Utilizing the multiple blower system of the present invention to meet the gas flow requirements of a fuel cell allows the system to take advantage of both low inertia impellers for control and low RPM and power consumption of the drive motor to provide the required gas flow and pressure.

[0055] FIG. 4 shows two blowers of FIGS. 1-3 of the dual centrifugal blower system 10 with an air intake assembly 100 attached to the axial inlet 15. The air intake assembly has an air intake casing 30 that is attachable to the blower casing 14. These figures show the air intake casing 30 and the blower casing 14 formed as a single piece. Although shown as such, the air intake casing 30 may be a separate unit from the blower casing 14, along with means for attaching the air intake casing 30 to the blower casing 14, in turn. Attachments for securing the air intake casing 30 to the blower casing 14 include screws, nuts and bolts, molded key-and-slot assemblies, slot-and-tab assemblies, twist-lock tab-and-groove assemblies, etc.

[0056] The air intake assembly 100 includes a frame (not shown), radial arms (not shown), a flapper 32, and a flapper connecting post 35 connected to the flapper 32. The radial arms are connected to the frame at one end and converge to form a receptacle that receives the flapper connecting post 35. The frame may be held in place by compression using an O-ring 33. The air intake assembly 100 prevents zero-flow conditions from backflowing from the fan or other process air, which, at high temperatures, can damage the solid oxide fuel cell (SOFC) and catalyst through oxidation. While the air intake assembly 100 is described and illustrated as a flapper-type check valve, other check valve assemblies are contemplated, such as ball check valves and spring-piston check valves.

[0057] Flapper 32 is a soft elastomer that creates little pressure drop when opening, using the slight inherent stiffness and spring constant of the material to close and seal. This movement is shown in Figure 4, where flapper 32 is shown in solid lines in the closed position and flapper 32 is shown in dashed lines in the open position. When the blower is engaged and air is drawn into axial inlet 15, flapper 32 opens. If the blower is turned off or system back pressure causes air to flow in the direction opposite the arrow shown, flapper 32 closes and stops the air flow.

[0058] The filter assembly includes a filter frame, a filter 28, and an O-ring 33. The top 34 of the filter 28 is held in place by compression using the O-ring 33. The filter frame is held in place by compression using the O-ring 33. The filter assembly, following the check valve assembly, filters the incoming air for filtering particulates, volatile compounds, sulfur compounds, hydrocarbons, etc., desiccants to reduce moisture, and active filtration media to remove airborne contaminants. The filter 28 is a type of reticulated foam (with low pressure drop) that may be doped with specific materials to perform the tasks listed above, such as a sulfur trap. The particle size range filtered can be from 1 to 100 microns or larger.

[0059] Although the filter assembly has been described as having a filter frame, filter 28, and O-ring 33, other embodiments are contemplated. For example, a single form-fitted foam could be fitted into place without the need for a filter frame and O-ring 33.

[0060] An air intake assembly 100 having a check valve assembly and multiple filter assemblies attached to the centrifugal blower system 10 filters the incoming air prior to the check valve to filter out particulates, volatile compounds and / or moisture.

[0061] 4, outer filter 31 is mounted on air intake assembly 100. Outer filter 31 may be flat or cylindrical in shape, with the filter material extending over a bottom end that is open and sized to receive air intake assembly 100. When outer filter 31 is mounted on air intake casing 30, air can flow through the top of outer filter 28 and partially along the sides.

[0062] 4, the upper filter 34 is mounted on the air intake assembly 100, similar to the lower filter 31. The outer filter 34 may also be flat or cylindrical. When the upper filter 34 is mounted on the air intake casing 30 and placed within the outer casing of a unit, such as a fuel cell, the inner surface of the casing 30 can be used to seal the open top end of the upper filter 34. Air can then only flow partially through the sides of the upper filter 34.

[0063] Figure 5 is a side perspective view of the dual blower system of the present invention. As indicated by the arrows in Figure 5, the gaseous medium is first taken in through the axial inlet 15 of the blower 11 after passing through the air filter 28 and / or air intake assembly 100, then discharged through the radial outlet 16 to the duct 13 and then to the axial inlet 22 of the second blower 12. The gaseous medium is then discharged through the radial outlet 23.

[0064] 6A-6C illustrate the use of a flow straightener 36, which is positioned at the outlet 23 of the blower 12 and is shown in use in FIG. 5. The flow straightener 36, shown without the flow straightener in FIG. 6A, functions to reduce turbulence 37 in the flow of gaseous medium discharged from the radial outlet 23. In FIG. 6B, the flow straightener 36 is provided with circular perforations 38, which function to straighten the flow of gaseous medium discharged from the axial outlet 23. FIG. 6C illustrates the use of rectangular flow passages 39 in the flow straightener 36.

[0065] 5, 11 and 12A, downstream of the flow straightener 36 and downstream of at least one blower unit in the row, a flow sensing element or flow meter 404 is provided to provide a sensor means for measuring the flow rate discharged from the radial outlet 23.

[0066] 7A and 7B, bottom and top perspective views, respectively, of two mechanically connected blower unit pairs of individual blowers 11 and 12 are shown. The mechanical connection between the two blower unit pairs can be achieved by heat welding or molding, or by using any mechanical connection means, such as screws, bolts, adhesives, etc. In FIGS. 7A and 7B, the two blower unit pairs are substantially juxtaposed to each other, i.e., positioned adjacent to each other, although any change, angle, or movement of the two blowers in each pair and / or the entire blower unit pair is contemplated and can be adjusted by one skilled in the art. In one embodiment, the two blower unit pairs can be juxtaposed to each other in the same plane.

[0067] 8A and 8B show the movement of gas flow housing 24 of blower unit 12 shown in FIGS. 7A and 7B, but now tucked under bottom 41 of blower unit 11. FIG.

[0068] 9A and 9B, there are shown overhead, top, and bottom views, respectively, of two mechanically connected blower unit pairs of individual blowers 11 and 12. As shown in FIGS. 7 and 8, the two blower unit pairs are substantially juxtaposed, i.e., positioned adjacent to one another, although any change, angle, or movement of the two blowers in each pair and / or the blower unit pair as a whole is contemplated and can be adjusted by one skilled in the art.

[0069] Specifically, Figures 10A and 10B show the movement of gas flow housing 24 of blower unit 12 shown in Figures 9A and 9B, but now tucked under bottom 41 of blower unit 11.

[0070] 7-10 , in one non-limiting embodiment, only one of the two mechanically connected blower unit pairs, the individual blowers 11 and 12, may include the air filter 28 and / or air intake assembly 100, as described herein. The selection of which of the two mechanically connected blower unit pairs, the individual blowers 11 and 12, includes the air filter 28 and / or air intake assembly 100 may be determined by one skilled in the art, and in one embodiment, may include one pair being used to supply gaseous medium to a reformer and the other pair being used to supply gaseous medium to a fuel cell in a fuel cell system, as described herein. Additionally, the flapper 32 shown in FIG. 4 may be used in only one of the two mechanically connected blower unit pairs.

[0071] Also provided herein is a fuel cell assembly including a plurality of individual fuel cells (each having an electrolyte medium, a cathode, and an anode) and at least one centrifugal blower system 10 as described herein to provide a flow of gaseous medium to the fuel cell assembly. In one embodiment, the fuel cell is a solid oxide fuel cell, preferably a tubular solid oxide fuel cell assembly. The tubular solid oxide fuel cell assembly may include a first blower system 10 for supplying fuel to an anode component of the tubular solid oxide fuel cell element and a second blower system 10 for supplying an oxidant gas source to a cathode component of the tubular solid oxide fuel cell element.

[0072] Referring to FIG. 11 , an integrated gaseous fuel CPOX reformer-fuel cell system 400 includes a gaseous fuel CPOX reformer section 401 coupled to a fuel cell section 428. The reformer section 401 includes an interconnected dual centrifugal blower system 402 for introducing a mixture of air and gaseous fuel into a conduit 403 and for directing this and other gaseous streams (including the gaseous fuel-air mixture and the hydrogen-rich reformate) through various gas flow paths in the reformer section and fuel cell section, as shown, for example, in FIGS. 1-3 . The conduit 403 may include a flow meter 404 and a thermocouple 405. These and similar devices may be positioned at various locations within the gaseous fuel CPOX reformer section and fuel cell section to measure, monitor, and control the operation of the integrated reformer-fuel cell system 400.

[0073] In a start-up operating mode of the integrated gaseous fuel CPOX reformer-fuel cell system 400, a mixture of air and propane at ambient temperature is introduced into conduit 403 by centrifugal blower system 402. Propane is drawn at relatively low pressure from a gaseous fuel storage tank 413 through inlet 406 into connecting duct 403 of centrifugal blower system 402 via fuel line 414 equipped with optional thermocouple 415, flow meter 416, and flow control valve 417. The air and propane are thoroughly mixed within centrifugal blower system 402 before the gaseous mixture is released therefrom into conduit 403. The substantially homogeneous propane-air mixture (gaseous CPOX reaction mixture) enters manifold or plenum 420, which serves to more uniformly distribute the reaction mixture to the tubular CPOX reactor units 409.

[0074] In the start-up mode of operation of the CPOX reformer section 401, the igniter 423 initiates the CPOX reaction of the gaseous CPOX reaction mixture within the CPOX reaction zone 410 of the tubular CPOX reactor unit 409, thereby initiating the production of hydrogen-rich reformate. Once a steady-state CPOX reaction temperature (e.g., 240°C to 1,100°C) is reached, the reaction becomes self-sustaining and the igniter can be shut off. Thermocouples 425 are positioned adjacent one or more of the CPOX reaction zones 410 to monitor the temperature of the CPOX reaction occurring within the CPOX reactor unit 409. Temperature measurements can be relayed to the reformer control system 426 as monitored parameters.

[0075] The reformer section 401 may also include a current source, such as a rechargeable lithium-ion battery system 427, for powering electrically driven components such as the centrifugal blower system 402, flow meter 404, flow control valve 417, igniter 423, etc., during a start-up operating mode of the integrated reformer-fuel cell system 400, and, if desired, for storing excess power generated by the fuel cell section 428, e.g., during steady-state operation, for later use.

[0076] The fuel cell section 428 includes a fuel cell stack 429, an afterburner or tail gas burner 432, a centrifugal blower system 430 that introduces air evenly distributed by a manifold 431 to the cathode side of the fuel cell stack 429 to support the electrochemical conversion of fuel to electricity therein and to the afterburner 432 to support the combustion of the tail gas therein, and optional thermocouples 433 and flow meters 434 to provide temperature and pressure measurement inputs to the control system 426. The hydrogen-rich reformate produced in the gaseous CPOX reformer section 401 enters the fuel cell stack 429 where it is electrochemically converted to produce electricity and by-products water (steam) and carbon dioxide as gaseous emissions. This gaseous effluent, or tail gas, from the fuel cell stack 429 may contain combustible gases, such as hydrocarbons, unconsumed hydrogen, and / or other electrochemically oxidizable gases such as carbon monoxide, which then enter the afterburner 432 for combustion into water (steam) and carbon dioxide using air supplied by the centrifugal blower system 430. Optionally, the heat contained in the hot gaseous effluent from the afterburner 432 can be recovered and used to heat one or more fluid streams, for example, to convert water to steam for use in ATR and / or SR reforming.

[0077] The centrifugal blower system 10 described herein includes a blower control system (FIG. 12A) and a diagrammatic representation of its control logic (FIG. 12B) for the centrifugal blower system of the present invention. As will be appreciated by those skilled in the art, these blower control operations can be performed by a suitably programmed microprocessor that can be configured to independently control the operation of the blower units in the bank of blower units.

[0078] The centrifugal blower system of the present invention can manage the gas flow requirements in a variety of applications. Figures 13A and 13B illustrate the use of the blower system of the present invention to supply and mediate gas flow to a tubular-type SOFC assembly (Figures 14A and 14B).

[0079] In the tubular SOFC assembly or stack 140 of Figures 13A and 13B, a first blower system 141 supplies a gaseous fuel, such as hydrogen, to a manifold 142 for distribution through an internal array 143 of tubular SOFC elements. Each tube in the array 143 may be of known or conventional construction and has an innermost fuel-contacting anode layer, an intermediate electrolyte layer, and an outer cathode layer, as shown in Figure 13C. A second blower system 144 distributes air, initially at ambient temperature, through a manifold 145, from which it is discharged to provide a source of oxygen for the cathode component of each tubular SOFC element. The air entering the manifold 145 obtains heat from hot combustion gases exiting a tail burner 146 into a heat exchanger 147. The dotted lines indicate the flow path of the heated air, which exits the manifold 145, passes through the SOFC array 143, and enters the tail burner 146, where it provides oxygen to support the combustion of unused fuel present in the exhaust gases that exit the tubular SOFC elements into the exhaust manifold 148, from where they enter the tail burner. Finally, the hot combustion gases enter a heat exchanger 147, where they serve to preheat the incoming air provided by the first blower system 141, previously shown.

[0080] While the present invention has been described in detail for purposes of illustration, it will be appreciated that these details are for that purpose only and that various modifications may be made thereto by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. 1. A centrifugal blower system, comprising: A row of blower units, each blower unit in the row comprising: a casing having an axial inlet and a radial outlet; an impeller disposed within the casing for drawing gaseous medium into the axial inlet at a first pressure and expelling gaseous medium from the radial outlet at a second, higher pressure; a motor for driving the impeller; and a duct connecting a radial outlet of at least one blower unit in the row of blower units to an axial inlet of at least one other blower unit in the row of blower units; wherein an axial inlet of at least one blower unit in the row of blower units is positioned substantially opposite an axial inlet of at least one other blower unit in the row of blower units.

2. 2. The centrifugal blower system of claim 1, wherein the radial outlets of at least two blower units in the row are substantially opposite each other.

3. The duct is a gas flow restriction wall defining an internal gas flow passage; and a gas inlet for introducing a gaseous medium into the gas flow path of the duct, the gas inlet being formed within or connected to the gas flow restriction wall of the duct; 10. The centrifugal blower system of claim 1, further comprising:

4. 2. The centrifugal blower system according to claim 1, wherein an inner wall of the duct is configured to be substantially parallel to a path of a gaseous medium discharged from a radial outlet of a blower unit to which the duct is connected.

5. 2. The centrifugal blower system of claim 1, wherein the outlets of successive blower units in the row are provided with gas flow housings for receiving gas flow from the outlets, the walls of the gas flow housings being configured to be substantially parallel to a path of gaseous medium discharged from the outlets.

6. 2. The centrifugal blower system of claim 1, wherein the outlet of one blower unit in the row is oriented at an angle of approximately 0°, 90°, 180°, or 270° relative to the inlet of a successive blower unit in the row.

7. 2. The centrifugal blower system of claim 1, wherein the pitch angle of the outlet of one blower unit in the row is 0°, 30°, 60°, or 90° relative to the inlet of the next blower in the row.

8. 10. The centrifugal blower system of claim 1, wherein at least one blower unit in the row has a greater gas pressure and gas flow capacity than another blower unit in the system.

9. 2. The centrifugal blower system of claim 1, wherein the second higher pressure is higher than a second higher pressure generated in a centrifugal blower system in which an axial inlet of at least one blower unit in the row of blower units is arranged in substantially the same direction as an axial inlet of at least one other blower unit in the row of blower units.

10. 10. The centrifugal blower system of claim 9, wherein the second higher pressure is about 1% to about 10% higher than a second higher pressure in a centrifugal blower system in which an axial inlet of at least one blower unit in the row of blower units is arranged in substantially the same direction as an axial inlet of at least one other blower unit in the row of blower units.

11. an air filter on an axial inlet of the at least one blower unit, the radial outlet of the blower unit being connected to the duct; 2. The centrifugal blower system of claim 1, wherein the centrifugal blower system has a height that is less than a height of a centrifugal blower system in which an axial inlet of at least one blower unit in the row of blower units is oriented in substantially the same direction as an axial inlet of at least one other blower unit in the row of blower units.

12. 12. The centrifugal blower system of claim 11, wherein the height of the centrifugal blower system is up to 30% less than the height of a centrifugal blower system in which the axial inlet of at least one blower unit in the row of blower units is arranged in substantially the same direction as the axial inlet of at least one other blower unit in the row of blower units.

13. 1. An air intake assembly comprising: an air intake assembly casing having an air inlet and an air outlet, the air outlet being connected to an axial inlet of a blower casing of the at least one blower unit having a radial outlet connected to the duct; a check valve mounted within the air intake assembly casing and positioned to allow air to flow from the air inlet to the air outlet and to prevent air from flowing from the air outlet to the air inlet; an air intake assembly having The centrifugal blower system of claim 1 further comprising:

14. 14. The centrifugal blower system of claim 13, wherein the check valve comprises a flexible diaphragm attached to an inlet of the air intake assembly casing.

15. 15. The centrifugal blower air intake device of claim 14, wherein the air intake assembly further comprises at least one air filtration unit disposed in at least one of the air inlet and the air outlet.

16. 2. The centrifugal blower system of claim 1, wherein an outlet of a last blower in the row of blower units communicates with a flow sensing element located downstream of at least one other blower unit in the row of blower units.

17. 2. The centrifugal blower system of claim 1, further comprising a flow straightener located at the outlet of the last blower in the series and upstream of the flow sensing element.

18. 2. The centrifugal blower system of claim 1, wherein a blower unit pair is formed by connecting one blower unit to another blower unit through the duct, and the centrifugal blower system comprises at least two blower unit pairs mechanically connected to each other, the two blower unit pairs being substantially juxtaposed to each other.

19. 20. The centrifugal blower system of claim 18, wherein the at least two pairs of blower units are substantially juxtaposed to one another in the same plane.

20. One of the pair of blower units 1. An air intake assembly comprising: an air intake assembly casing having an air inlet and an air outlet, the air outlet being connected to an axial inlet of a blower casing of the at least one blower unit having a radial outlet connected to the duct; a check valve mounted within the air intake assembly casing and positioned to allow air to flow from the air inlet to the air outlet and to prevent air from flowing from the air outlet to the air inlet; an air intake assembly having 20. The centrifugal blower system of claim 18, further comprising:

21. 10. The centrifugal blower system of claim 1, further comprising a microprocessor configured to independently control operation of the blower units in the row of blower units.

22. 1. A fuel cell assembly comprising: a plurality of individual fuel cells, each fuel cell having an electrolyte medium, a cathode, and an anode; a fuel cell assembly including: At least one centrifugal blower system according to claim 1 for supplying a flow of gaseous medium to said fuel cell assembly; A fuel cell comprising:

23. 23. The fuel cell of claim 22, which is a solid oxide fuel cell.

24. 24. The fuel cell of claim 23, wherein the solid oxide fuel cell is a tubular solid oxide fuel cell assembly.

25. the tubular solid oxide fuel cell assembly a first blower system for supplying fuel to the anode component of the tubular solid oxide fuel cell element; a second blower system for supplying a source of oxidant gas to the cathode component of said tubular solid oxide fuel cell element.

26. In the centrifugal blower system, the second higher pressure is a second, higher pressure generated in a centrifugal blower system in which the axial inlet of at least one blower unit in the row of blower units is oriented in substantially the same direction as the axial inlet of at least one other blower unit in the row of blower units; 23. The fuel cell of claim 22, wherein

27. the centrifugal blower system further comprises an air filter on an axial inlet of at least one blower unit, the radial outlet of which is connected to the duct; 23. The fuel cell of claim 22, wherein the height of the centrifugal blower system is less than the height of a centrifugal blower system in which the axial inlet of at least one blower unit in the row of blower units is oriented in substantially the same direction as the axial inlet of at least one other blower unit in the row of blower units.

28. The centrifugal blower system comprises:

1. An air intake assembly comprising: an air intake assembly casing having an air inlet and an air outlet, the air outlet being connected to an axial inlet of a blower casing of at least one blower unit, the radial outlet of which is connected to a duct; a check valve mounted within the air intake assembly casing and positioned to allow air to flow from the air inlet to the air outlet and to prevent air from flowing from the air outlet to the air inlet; an air intake assembly having 23. The fuel cell of claim 22, further comprising:

29. 23. The fuel cell of claim 22, wherein the centrifugal blower system has an outlet of the last blower in the row that leads to a flow sensing element located downstream of at least one other blower unit in the row.

30. In the centrifugal blower system, a blower unit pair is formed by connecting one blower unit to another blower unit through the duct; 23. The fuel cell of claim 22, wherein the centrifugal blower system comprises at least two pairs of blower units mechanically connected to one another, the two pairs of blower units being substantially juxtaposed to one another.

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