Abstract:
A rotary device containing a housing having a curved inner surface with a profile equidistant form a trochoidal curve, an eccentric mounted on a shaft disposed within the housing, a rotor mounted on the eccentric shaft which contains at least three sides, a partial bore located at the intersection of adjacent sides, and at least three rollers rotatably mounted within the partial bores of the roller. The rotor is comprised of a front face, a back face, a first side, a second side, and a third side. On each front and back face, between adjacent sides, an opening is formed. The openings are on opposing front and back faces are offset from a centerline of the rotary device.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application is a continuation-in-part of applicants&#39; patent application U.S. Ser. No. 09/977,002, filed on Oct. 12, 2001, which was a continuation-in-part of patent application U.S. Ser. No. 09/536,332, filed on Mar. 24, 2000 now U.S. Pat. No. 6,266,952, which was a continuation-in-part of U.S. Ser. No. 09/416,291, filed on Oct. 14, 1999 now U.S. Pat. No. 6,499,301, which was a continuation-in-part of U.S. Ser. No. 09/396,034, filed on Sep. 15, 1999 now U.S. Pat. No. 6,301,898, which in turn was a continuation-in-part of patent application U.S. Ser. No. 09/181,307, filed on Oct. 28, 1998 now abandoned. 
    
    
     FIELD OF THE INVENTION 
     A rotary device containing a housing having a curved inner surface with a profile equidistant from a trochoidal curve, an eccentric mounted on a shaft disposed within the housing, a rotor mounted on the eccentric shaft which contains at least three faces, a partial bore located at the intersection of adjacent faces, and at least three rollers rotatably mounted within the partial bores of the roller. The rotor is comprised of a front face, a back face, a first side, a second side, and a third side. On each front and back face, between adjacent sides, an opening is formed. 
     BACKGROUND OF THE INVENTION 
     In applicants&#39; U.S. Pat. No. 5,1131,551, there is disclosed and claimed a rotary device comprised of a housing comprising a curved inner surface with a profile equidistant form a trochoidal curve, an eccentric mounted on a shaft disposed within said first housing, a first rotor mounted on said eccentric shaft which is comprised of a first side, a second side, and a third side, a first partial bore disposed at die intersection of said first side and said second side, a second partial bore disposed at the intersection of said second side and said third side, a third partial bore disposed at the intersection of said third side and said first side, a first solid roller disposed fluid rotatably mounted within said first solid bore, a second solid roller disposed and rotatably mounted within said second partial bore, and a third solid roller disposed and rotatably mounted within said third pairtial bore. The rotor is comprised of a front face, a back face, a first side, a second side, and a third side, wherein a first opening is formed between and communicates between said front face and said first side, a second opening is formed between and communicates between said back face and said first side, wherein each of said first opening and said second opening is substantially equidistant and symmetrical between said first partial bore and said second partial bore, a third opening is formed between and communicates between said front face and said second side, a fourth opening is formed between and communicates between said back face and said second side, wherein each of said third opening and said fourth opening is substantially equidistant and symmetrical between said second partial bore and said third partial bore, a fifth opening is formed between and communicates between said front face and said third side, and a sixth opening is formed between and communicates between said back face and said third side, wherein each of said fifth opening and said sixth opening is substantially equidistant and symmetrical between said third partial bore and said first partial bore. Each of said first partial bore, said second partial bore, and said third partial bore is comprised of a centerpoint which, as said rotary device rotates, moves along said trochoidal curve. Each of said first opening, said second opening, said third opening, said fourth opening, said fifth opening, and said sixth opening has a substantially U-shaped cross-sectional shape defined by a first linear side, a second linear side, and an arcuate section joining said first linear side and said second linear side, wherein said first linear side and said second linear side are disposed with respect to each other at an angle of less than ninety degrees, and said substantially U-shaped cross-sectional shape has a depth which is at least equal to its width. The diameter of said first solid roller is equal to the diameter of said second solid roller, and the diameter of said second solid roller is equal to the diameter of said third solid roller. The widths of each of said first opening said second opening, said third opening, said fourth opening, said fifth opening, and said sixth opening are substantially the same, and the width of each of said openings is less than the diameter of said first solid roller. Each of said first side, said second side, and said third side has substantially the same geometry and size and is a composite shape comprised of a first section and a second section, wherein said first section has a shape which is different from said second section. 
     A similar patent, U.S. Pat. No. 6,301,898, issued to applicants&#39; on Oct. 16, 2001. This patent discloses and claims a rotary device comprised of a housing comprising a curved inner surface with a profile equidistant from a trochoidal curve, an eccentric mounted on a shalt disposed within said housing, a first rotor mounted on said ecceitric which is comprised of a first side, a second side, and a third side, a first partial bore disposed at the intersection of said first side and said second side, a second partial bore disposed at the intersection of said second side and said third side, a third partial bore disposed at the intersection of said third side and said first side, a first hollow roller disposed and rotatably mounted within said first solid bore, a second hollow roller disposed and rotatably mounted within said second partial bore, and a third hollow roller disposed and rotatably mounted within said third partial bore, wherein: (a) said rotor is comprised of a front face, said back face, said first side, said second side, and said third side, wherein: 1. a first opening is formed between and communicates between said front face and said first side, 2. a second opening is formed between and communicates between said back face and said first side, wherein each of said first opening and said second opening is substantially equidistant and symmetrical between said first partial bore and said second partial bore, 3. a third opening is formed between and communicates between said front face and said second side, 4. a fourth opening is formed between and communicates between said back face and said second side, wherein each of said third opening and said fourth opening is substantially equidistant and symmetrical between said second partial bore and said third partial bore, 5. fifth opening is formed between and communicates between said front face and said third side, and 6. a sixth opening is formed between and communicates between said back face and said third side, wherein each of said fifth opening and said sixth opening is substantially equidistant and symmetrical between said third partial bore and said first partial bore; (b) each of said first partial bore, said second partial bore, and said third partial bore is comprised of a centerpoint which, as said rotary device rotates, moves along said trochoidal curve; (c) each of said first opening, said second opening, said third opening, said fourth opening, said fifth opening, and said sixth opening has a substantially U-shaped crosssectional shape defined by a first linear side, a second linear side, and an arcuate section joining said first linear side and said second linear side, wherein: 1. said first linear side and said second linear side are disposed with respect to each other at an angle of less than ninety degrees, and 2. said substantially U-shaped cross-sectional shape has a depth which is at least equal to its width; (d) the diameter of said first hollow roller is equal to the diameter of said second hollow roller, and the diameter of said second hollow roller is equal to the diameter of said third hollow roller; (e) the widths of each of said first opening said second opening, said third opening, said fourth opening, said fifth opening, and said sixth opening arc substantially the same, and the width of each of said openings is less than the diameter of said first hollow roller; and (f) each of said first side, said second side, and said third side has substantially the same geometry and size and is a composite shape comprised of a first section and a second section, wherein said first section has a shape which is different from said second section. The entire disclosure of each of U.S. Pat. Nos. 5,431,551 and 6,301,898 is hereby incorporated by reference into this specification. 
     The compressors of U.S. Pat. Nos. 5,431,551 and 6,301,898, although substantial better than prior art compressors, exhibited dynamic losses in the port areas due to restricted flow areas. It is an object of this invention to provide a compressor which has lower port losses. 
     SUMMARY OF THE INVENTION 
     In accordance with this invention, there is provided a rotary positive displacement compressor assembly comprising a housing having a curved inner surface with a profile equidistant from a trochoidal curve, and eccentric mounted on a shaft disposed within said housing, a rotor mounted on said eccentric shaft which is comprised of a bore with an axial centerline, a front face, a back face, a first side, a second side, and a third side, a first partial bore disposed at the intersection of the first side and the second side, a second partial bore disposed at the intersection of said second side and said third side, a third partial bore disposed at the intersection of said third side and said first side, a first roller disposed and rotatably mounted within said first partial bore, a second roller disposed and rotatably mounted within said second partial bore and a third roller disposed and rotatably mounted within said third partial bore. In this assembly, a first opening is formed between and communicates between said front face and said first side, a second opening is formed between and communicates between said back face and said first side, a third opening is formed between and communicates between said front face and said second side, a fourth opening is formed between and communicates between said back face and said second side, a fifth opening is formed between and communicates between said front face and said third side, and a sixth opening is formed between and communicates between said back face and said third side. In the assembly, a first transverse rotor centerline extends through said first side, a second transverse rotor centerline extends though said second side, and a third transverse rotor centerline extends through said third side, provided that each of said first transverse rotor centerline, said second transverse rotor centerline, and said third transverse rotor centerline also extends through said axial centerline of said bore in said rotor. The first opening is comprised of a first opening centerline, said second opening is comprised of a second opening centerline, provided that said first opening centerline and said second opening centerline are each offset from said rotor transverse centerline by at least 0.1 inches and from about 0.x to about 4.x, wherein x is equal to the width of said opening. The third opening is comprised of a third opening centerline, said fourth opening is comprised of a fourth opening centerline, provided that said third opening centerline and said fourth opening centerline are each offset from said rotor transverse centerline by at least 0.1 inches and from about 0.x to about 4.x, wherein x is equal to the width of said opening. The fifth opening is comprised of a first opening centerline, said sixth opening is comprised of a second sixth centerline, provided that said fifth opening centerline and said sixth opening centerline are each offset from said rotor transverse centerline by at least 0.1 inches and from about 0.x to about 4.x, wherein x is equal to the width of said opening. In the assembly, the degree to which said first opening centerline, said third opening centerline, and said fifth opening centerline are offset from said rotor transverse centerlines are the same; and the degree to which said second opening centerline, said fourth opening centerline, and said sixth opening centerline are offset from said rotor transverse centerlines are the same. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The claimed invention will be described by reference to the specification and the following drawings, in which: 
     FIG. 1 is a perspective view of one preferred rotary mechanism claimed in U.S. Pat. No. 5,431,551; 
     FIG. 2 is an axial, cross-sectional view of the mechanism of FIG. 1; 
     FIG. 3 is a perspective view of the eccentric crank of the mechanism of FIG. 1; 
     FIG. 4A is a transverse, cross-sectional view of the eccentric crank of FIG. 3; 
     FIG. 5 is a perspective view of the rotor of the device of FIG. 1; 
     FIG. 6 is an axial, cross-sectional view of the rotor of FIG. 5; 
     FIG. 7 is a transverse, cross-sectional view of the rotor of FIG. 5; 
     FIG. 8 is an exploded, perspective view of the device of FIG. 1; 
     FIG. 9 is a sectional view of one hollow roller which can be used in the rotary positive displacement device of this invention; 
     FIG. 10 is a sectional view of another hollow roller which can be used in the rotary positive displacement device of this invention; 
     FIG. 11 is at schematic view of a modified rotor which can be used in the positive displacement device of this invention; 
     FIG. 12 is perspective view of one preferred rotor of the invention; 
     FIGS. 13A and 13B are front and side views of another preferred rotor of the invention; 
     FIGS. 14A and 14B are front and side views of another preferred rotor of the invention; and 
     FIG. 15 is a schematic vie of a preferred fuel processor assembly. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the first part of this specification, and by reference to FIGS. 1,  2 ,  3 ,  4 ,  4 A,  5 ,  6 ,  7 , and  8 ,  9 ,  10 , and  11 , a first guide rotor compressor will be described. Thereafter, in the second part of this specification, a second guided rotor compressor will be described. 
     FIGS. 1,  2 ,  3 ,  4 ,  4 A,  5 ,  6 ,  7 , and  8  are identical to the FIGS. 1,  2 ,  3 ,  4 ,  4 A,  5 ,  6 ,  7 , and  8  appearing in U.S. Pat. No. 5,431,551; and they are presented in this case to illustrate the similarities and differences between the rotary positive displacement device of such patent and the rotary positive displacement device of one embodiment of the instant application. The entire disclosure, the drawings, the claims, and the abstract of U.S. Pat. No. 5,431,551 are hereby incorporated by reference into this specification. 
     Referring to FIG. 5, it will be seen that rotor  300  is comprised of a bore  62  with an axial centerline  77  extending through the geometric center of said bore  62 . 
     Referring to FIGS. 1 through 8, and to the embodiment depicted therein, it will be noted that rollers  18 ,  20 ,  22 , and  24  (see FIGS. 1 and 8) are solid. In the rotary positive displacement device of one embodiment of the instant invention, however, the rollers used are hollow. 
     FIG. 9 is a sectional view of a hollow roller  100  which may be used to replace the rollers  18 ,  20 ,  22 , and  24  of the device of FIGS. 1 through 8. In the preferred embodiment depicted, it will be seen that roller  100  is a hollow cylindrical tube  102  with ends  104  and  106 . 
     Tube  102  may consist of metallic and/or non-metallic material, such as aluminum, bronze, polyethyletherketone, reinforced plastic, and the like. The hollow portion  104  of tube  102  has a diameter  110  which is at least about 50 percent of the outer diameter  112  of tube  102 . 
     The presence of ends  106  and  104  prevents the passage of gas from a low pressure region (not shown) to a high pressure region (not shown). These ends may be attached to tube  102  by conventional means, such as adhesive means, friction means, fasteners, threading, etc. 
     In the preferred embodiment depicted, the ends  106  and  104  are aligned with the ends  114  and  116  of tube  102 . In another embodiment, either or both of such ends  106  and  104  are not so aligned. 
     In one embodiment, the ends  106  and  104  consist essentially of the same material from which tube  102  is made. In another embodiment, different materials are present in either or both of ends  106  and,  104  and tube  102 . 
     In one embodiment, one of ends  106  and/or  104  is more resistant to wear than another one of such ends, and/or is more elastic. 
     FIG. 10 is sectional view of another preferred hollow roller  130 , which is comprised of a hollow cylindrical tube  132 , end  134 , end  136 , resilient means  138 , and O-rings  140  and  142 . In this embodiment, a spring  138  is disposed between and contiguous with ends  134  and  136 , urging such ends in the directions of arrows  144  and  146 , respectively. It will be appreciated that these spring-loaded ends tend to minimize the clearance between roller  130  and the housing in which it is disposed; and the O-rings  140  and  142  tend to prevent gas and/or liquid from entering the hollow center section  150 . 
     In the preferred embodiment depicted, the ends  134  and  136  are aligned with the ends  152  and  154  of tube  132 . In another embodiment, not shown, one or both of ends  144  and/or  146  are not so aligned. 
     The resilient means  138  may be, e.g., a coil spring, a flat spring, and/or any other suitable resilient biasing means. 
     FIG. 11 is a schematic view of a rotor  200  which may be used in place of the rotor  16  depicted in FIGS. 1,  5 ,  6 ,  7 , and  8 . Referring to FIG. 11, partial bores  202 ,  204 ,  206 , and  208  are similar in function, to at least some extent, the partial bores  61 ,  63 ,  65 , and  67  depicted in FIGS. 5,  6 ,  7 , and  8 . Although, in FIG. 11, a different partial bore has been depicted for elements  202 ,  204 ,  206 , and  208 , it still be appreciated that this has been done primarily for the sake of simplicity of representation and that, in most instances, each of partial bores  61 ,  63 ,  65 , and  67  will be substantially identical to each other. 
     It will also be appreciated that the partial bores  202 ,  204 ,  206 , and  208  are adapted to be substantially compliant to the forces and loads exerted upon the rollers (not shown) disposed within said partial bores and, additionally, to exert an outwardly extending force upon each of said rollers (not shown) to reduce the clearances between them and the housing (not shown). 
     Referring to FIG. 11, partial bore  202  is comprised of a ribbon spring  210  removably attached to rotor  16  at points  212  and  214 . Because of such attachment, ribbon spring  210  neither rotates nor slips during use. The ribbon spring  210  may be metallic or non-metallic. 
     In one embodiment, depicted in FIG. 11, the ribbon spring  210  extends over an are greater than 90 degrees, thereby allowing it to accept loads at points which are far from centerline  216 . 
     Partial bore  204  is comprised of a bent spring  220  which is affixed at ends  222  and  224  and provides substantially the same function as ribbon spring  210 . However, because bent spring extends over an are less than 90 degrees, it accepts loads primarily at around centerline  226 . 
     Partial bore  206  is comprised of a cavity  230  in which is disposed bent spring  232  and insert  234  which contains partial bore  206 . It Will be apparent that the roller disposed within bore  206  (and also within bores  202  and  204 ) are trapped by the shape of the bore and, thus, in spite of any outwardly extending resilient forces, cannot be forced out of the partial bore. In another embodiment, not shown, the partial bores  202 ,  204 ,  206 , and  208  do not extend beyond the point that rollers are entrapped, and thus the rollers are free to partially or completely extend beyond the partial bores. 
     Referring again to FIG. 11, it will be seen that partial bore  208  is comprised of a ribbon spring  250  which is similar to ribbon spring  210  but has a slightly different shape in that it is disposed within a cavity  252  behind a removable cradle  254 . As will be apparent, the spring  250  urges the cradle  254  outwardly along axis  226 . Inasmuch as the spring  250  extends more than about 90 degrees, it also allows force vectors near ends  256  and  258 , which, in the embodiment depicted, are also attachment points for the spring  250 . 
     Another Rotor Used in the Guided Rotor Compressors 
     FIG. 12 is a perspective view of another rotor  300  which is similar to the rotor  16  depicted in FIG. 5 of the U.S. Pat. No. 5,431,551 but differs therefrom in that the recesses  64 ,  66 ,  68 , and  70  are not aligned with the opposing recesses (not shown except for recesses  69  and  71 ) on the back face  74  of rotor  300 . Furthermore, and in the embodiment depicted, and unlike the situation with the rotor depicted in FIG. 5 of U.S. Pat. No. 5,431,551, the recesses of the rotor of this invention  64  and  68 , and  66  and  70 , are not aligned with each other. Similarly, and in the preferred embodiment depicted in FIG. 12, recess  71  and its opposing recess (not shown) of the back side  74  of the rotor, and recess  69  and its opposing recess (not shown) on the back side  74  of the rotor, are not aligned. 
     FIG. 13A is a front view of rotor  300 , and FIG. 13B is a side view of rotor  300 . Referring to FIG. 13A, and to the recesses  64 ,  66 ,  68 , and  70  depicted therein, it will be apparent to those skilled in the art that these recesses are present in the front face  302  of the rotor  300  and that similar recesses are present on the back face  74  of the rotor (see FIG.  12 ). 
     When the word opposing is used in this specification with regard to the recesses  64  et seq., it is meant to convey two recesses which are substantially opposite each other on opposing faces of the  300 . Thus, and referring to FIG. 13B, recesses  64  and  71  are not aligned with each other. 
     Although recesses  64  and  71  are substantially opposed to each other, these recesses are not aligned with each other. Each of the recesses  64  and  71  has a recess centerline defined as the plane bisecting the recess, orthogonally to the face; see centerlines  304 ,  306 ,  308 , and  310  respectively, which are offset from either the vertical axis  312  and/or the horizontal axis  314  (also known as the transverse centerline  314 ) of the rotor  300 . The offsets are identified as offsets  316  (from the vertical axis  312 ) and  318  (from the horizontal axis  314 ). 
     In the embodiment depicted in FIGS. 13A and 13B, the offset  316  from recess  71   64  is substantially equal to the offset  319  from recess  71 . In another embodiment, not shown, the offset  316  differs form the offset  319 . In either event, the offset  316 , and the offset  319 , which may be the same or different, each has a specified finite value which is function of the width  320 , * (see FIG.  13 B), as measured across the side face surface  322  of the rotor  300 . As will be apparent, this width  320  is often the maximum width of the recess  64 ,  66 ,  68 , or  70 , especially in the case of recesses with the oblong configurations shown in FIG.  12 . 
     The offsets  316  and  319 , which may be the same or different, are generally greater than 0 and less than 4 times x, provided that the offsets  316  and  319  are at least 0.1 inches. In one embodiment, the offsets  316  and  319  range from about 0.5x to about 3x. In another embodiment, the offsets  316  and  319  range from about 0.5x to about 2.5x. 
     In the embodiments depicted in the FIGS. 13A and 13B, the recesses  64  and  71  are so configured that their recess center lines  304  and  305  are substantially parallel to the center axis  312  of the rotor  300 . In another embodiment, not shown, the recess center lines are not necessarily parallel to the transverse centerlines  312 / 314  of the rotor. In this latter embodiment, the recess centerlines may intersect axes  312  or  314  to form an acute angle of from about 3 to 60 degrees. In either embodiment, the calculated offset  316 / 318  is measured from the axis  312  and/or axis  314  to the centerpoint of the recess in question. The centerpoint is defined as the intersection of the recess centerline and the arcuate surface 
     Referring again to FIG. 13A, and in the preferred embodiment depicted therein, it will be seen that rotor  300  is comprised of arcuate walls  322 ,  324 ,  326 , and  328 . In the preferred embodiment depicted, each of these arcuate walls is comprised of a continous arcuate section defined by a constant radius; and each of these arcuate walls defines a convex shape. In this embodiment, the rotor  300  is comprised of four walls  322  et seq. 
     In another embodiment, depicted in FIGS. 14A and,  14 B the rotor  330  is comprised of constant radius arcuate walls,  323 ,  325 ,  327 ,  329 , and  331  each of which has a continuous, concave arcuate shape. FIG. 14A is a front view of rotor  330 , and FIG. 14B is a side view of rotor  330 , taken form the top of said rotor  330 . 
     Referring to FIGS. 14A and 14B, the assembly depicted differs form the assembly depicted in FIGS. 13A and 13B in that the former assembly: (a) is comprised of five sides, including side  323 ,  325 ,  327 ,  329 , and  331 , which are substantially concave in shape and defined by a constant radius, (b) also includes partial roller bore  333 , necessitated because it contains five sides rather than four sides, and (c) also includes recess  335 , necessitated because it contains five sides rather than four sides. In the embodiment depicted in FIGS. 14A and 14B, because there is an odd number of sides in the rotor assembly  330 , no one recess is substantially opposed to any other recess. However, the extent of the offsets form each recess is still calculated in accordance with the range Y is equal to 0.x to about 4.x, wherein Y is the offset and is at least 0.1 inches, and x is the width of the opening. 
     In this embodiment, because there are an odd number of sides in the assembly, the transverse centerlines of the rotor  330  are not necessarily parallel to recess centerlines. 
     FIG. 15 is a flow diagram of a preferred fuel cell assembly  400 , comprised of a guided rotor compressor  402 , a fuel reformer  404 , and a fuel cell  406 . 
     The guided rotor compressor  402  may be any one of the guided rotor compressors described in U.S. Pat. No. 5,431,551 in U.S. Pat. No. 6,301,898, and/or in this specification. It is preferred that the bearing system  81  of such compressor (not shown in FIG. 15, but see FIG. 8) be a graphite bearing. Reference may be had, e.g., to U.S. Pat. Nos. 3,721,479, 5,017,022, 4,867,006, 4,880,326, 4,798,771, 4,545,337, and the like. The entire disclosure of each of these United States patents is hereby incorporated by reference into this specification. 
     The bearing system  81  is preferably a water-lubricated carbon bearing system. Thus, and referring again to FIG. 15, water is introduced into compressor  402  via line  408 . In this embodiment, it is preferred to introduce water at a temperature of less than about 120 degrees. Fahrenheit and at a pressure less than about 500 pounds per square inch gauge. 
     The compressor  402  is preferably made from corrosion resistant material. Thus, e.g., in one embodiment, the compressor  402  is made from either stainless steel and/or a material which is coated to prevent corrosion. Such corrosion resistant coatings are well known to those skilled in the art. Reference may be had, e.g., to U.S. Pat. Nos. 4,479,981, 5,691,048, 5,707,465, 4,866,116, 5,807,430, and the like. The entire disclosure of each of these United States patents is hereby incorporated by reference into this specification. 
     Referring again to FIG. 15, the compressor  402  feeds compressed gas via line  410  to fuel reformer  404 . In one embodiment, the gas fed via line  410  is natural gas at a pressure of from about 5 to about 500 pounds per square inch gauge. 
     In the embodiment depicted in FIG. 15, steam may optionally be fed to fuel reformer  404  via line  412 , and air may be fed to fuel reformer  404  via line  414 . In another embodiment, steam is fed form compressor  402  via line  410  to fuel reformer  404 . 
     One may use any of the fuel reformers known to those skilled in the art. Reference may be had, e.g., to U.S. Pat. Nos. 6,301,898, 5,141,824, 4,923,868, 5,637,414, 5,484,577, 4,642,273, 5,268,240, and the like. The entire disclosure of each of these United States patents is hereby incorporated by reference into this specification. 
     Flowing from the reformer  4044  will be hydrogen (within line  416 ), and waste gas (fed to external receptacle or use via line  418 ). The hydrogen, which is preferably substantially pure, is fed to the fuel cell  406 , wherein it is converted to electricity. 
     It is to be understood that the aforementioned description is illustrative only and that changes can be made in the apparatus, in the ingredients and their proportions, and in the sequence of combinations and process steps, as well as in other aspects of the invention discussed herein, without departing from the scope of the invention as defined in the following claims.