Apparatus for transferring heat to fluids

Apparatus is provided for transferring heat to fluids by the use of magnets. A first plurality of magnets is mounted in a housing in a pattern having a circular cross section. A second plurality of magnets is mounted in spaced relationship with respect to the first plurality and means are provided for moving one of the plurality of magnets relative to the other. Two concentric conductive members or sleeves of generally cylindrical shape are located in the magnetic field between the two pluralities. The two sleeves form an annular passage extending longitudinally of the magnets through which fluid to be heated is passed. The magnetic field causes the conductive sleeves to be heated by induction and transfer the heat to the fluid in an efficient manner. The inner sleeve preferably has projections extending toward the outer sleeve with longitudinally-extending passages therethrough. The outer sleeve can also have outwardly-extending projections or ridges located between rows of the magnets in the second plurality. Cooling air can be supplied outside both sleeves past the magnets of the two pluralities. This cooling air, now preheated, can be supplied to the inlet of a fluid compressor, the outlet of which communicates with the annular passage between the sleeves to supply the fluid therethrough.

This invention relates to apparatus for transferring heat from conductive 
members located in a magnetic field to fluid passing therethrough. 
The subject matter is disclosed in U.S. Pat. and Trademark Office 
Disclosure Document No. 070,540. 
The closest known prior art are my U.S. Pat. Nos. 3,821,508, issued June 
28, 1974, and 3,899,885, issued Aug. 19, 1975. Those patents disclose a 
first plurality or group of magnets disposed in a circular pattern, as 
viewed in transverse cross section, and a second plurality or group of 
magnets maintained in spaced relationship with respect to the first 
plurality. A conductive member is positioned in the space between the two 
groups of magnets and one of the groups of magnets is rotated to establish 
variable flux therebetween by the alternate retraction and repulsion, or 
variation in the strength of the retraction or repulsion, of the magnets. 
This induces heating of the conductive member and a fluid, such as air, is 
then moved past the heated member, in heat-transfer relationship. The 
fluid then becomes heated and ready to impart energy as it exits as a 
heated working fluid. 
In accordance with the present invention, a first conductive member or 
sleeve is located around the first plurality of magnets and is of 
generally cylindrical shape. A second conductive member or sleeve is 
located outside the first sleeve in coaxial relationship and is of 
generally cylindrical shape, with the two sleeves forming an annular 
passage extending longitudinally between the first and second plurality of 
magnets. Fluid is then passed through the annular passage formed by the 
sleeves with heat being transferred thereto from both of the sleeves which 
are heated by the variable flux established by the rotation of one of the 
plurality of magnets, preferably the first. The first sleeve can have a 
plurality of projections extending toward the second sleeve, preferably 
with openings or longitudinal passages in the projections through which 
some of the fluid can pass. The second sleeve can also have outwardly 
extending projections or ridges extending outwardly between some of the 
rows of magnets of the second plurality for improved heat transfer 
relationship. 
The first and second pluralities of magnets can be located in a housing 
having passages through which cooling fluid can be directed past the first 
plurality of magnets and also past the second plurality of magnets, more 
specifically between the inner surface of the first sleeve and the first 
plurality of magnets, and between the outer surface of the second sleeve 
and the second plurality of magnets. This cooling fluid, now heated, can 
be supplied to the inlet of a compressor, the outlet of which supplies 
compressed fluid through the annular passage formed by the sleeves. A 
common engine can be employed to drive the compressor and also to rotate 
the rotatable plurality of magnets in the housing. 
It is, therefore, a principal object of the invention to provide improved 
apparatus for heating a fluid by means of a magnetic field. 
Another object of the invention is to provide two spaced pluralities of 
magnets with two conductive members forming a passage therebetween through 
which fluid can flow for heat transfer relationship from the conductive 
members which are heated by the magnetic field established between the 
magnets and by movement of one of the pluralities. 
A further object of the invention is to provide conductive members between 
two pluralities of magnets, one of which is rotated relative to the other, 
with a compressor for supplying fluid through the passage and with the 
compressor intake receiving cooling fluid flowing past the two pluralities 
of magnets outside of the passage.

Referring particularly to FIGS. 1-3, overall apparatus embodying the 
invention is indicated at 10. The apparatus includes a heating unit 
indicated at 12, a compressor 14, and an engine 16 for driving the 
compressor and the heating unit. Heated, compressed fluid from the heating 
unit 12 is used to operate various devices, pneumatic rock drills 
schematically shown at 18, in this instance. The engine 16 can be fueled 
with gasoline or diesel oil and drives the compressor 14 through a shaft 
20 and rotates a shaft 22 of the heating unit 12, which will be discussed 
subsequently. The overall heating unit 12 is mounted on a base 24 with 
upstanding end frames 26 and 28. These are connected by a tie rod 30 
having end nuts 32 and a spacer tube 34 between the end frames. 
Referring to FIG. 4, the end frame 28 has an opening 36 through which the 
drive shaft 22 extends. The shaft is rotatably supported in a bearing 38 
which is held in a bearing mount 40. The mount 40, in turn, is suitably 
affixed to the end frame, as by welding or suitable flanges (not shown). 
The shaft 22, or an extension thereof, also is received in a bearing 42 
held in a bearing mount 44 affixed to the other end frame 26. 
A rotor 46 is mounted on the shaft 22 and has a first plurality of magnets 
48 mounted therein with the legs or ends extending radially outwardly and 
forming a circular pattern in transverse cross section. The magnets can be 
of the permanent type, as shown, or electromagnets can be employed. The 
first plurality of the magnets 48 are rotated with the rotor 46 when the 
shaft 22 is driven by the engine 16. 
An outer housing 50 is positioned around the first plurality of magnets and 
the rotor 46, being suitably supported by the legs 52 (FIG. 1) on the base 
24. The housing 50 carries a second plurality of magnets 54 which are also 
located in a circular pattern, concentrically positioned with respect to 
the first plurality of magnets. 
In accordance with the invention, a first conductive, generally cylindrical 
member or sleeve 56 is positioned in the annular space between the two 
pluralities of magnets and is located closer to the first plurality. The 
sleeve 56 is supported on carbon sleeves 58 and 60 located on the bearing 
mounts 40 and 44. A second conductive, generally cylindrical member or 
sleeve 62 is located in the annular space between the two pluralities of 
magnets and outside the first sleeve 56, being concentrically positioned 
with respect thereto. The sleeves are both heated by induction and both 
rapidly transfer heat to fluid. The increased heat transfer can enable the 
final temperature of the outlet fluid to be higher or the overall heating 
unit can be shorter. The unit can also be reduced in diameter. 
The sleeves 56 and 62 are suitably affixed to end manifolds 64 and 66 which 
form annular chambers 68 and 70. These communicate with an annular, 
longitudinally-extending passage 72 formed by the concentric sleeves 56 
and 62. The manifolds 64 and 66 are supported by the end frames 26 and 28 
through bolts 74 and nuts 76, with springs 78 located on the bolts 74 
between the manifolds and the end frames. This construction enables the 
sleeves 56 and 62 to extend longitudinally toward and away from the end 
frames for contraction and expansion purposes. The sleeves and the 
manifolds at the ends can be made of heat resistant metal not affected by 
oxidation at elevated temperatures; such materials include Inconel, 
nichrome, and certain stainless steel alloys. 
Heat transferred to fluid flowing through the passage 72 from the sleeves 
56 and 62 is enhanced by a plurality of projections or heat dispensers 80 
located on the outer surface of the sleeve 56 and extending outwardly 
toward the sleeve 62. The projections 80 have longitudinally-extending 
passages 82 therein through which a portion of the fluid directed through 
the passage 72 can flow. The projections 80 extend substantially to the 
inner surface of the sleeve 62 but can move relative thereto for radial 
expansion and contraction. 
The outer sleeve 62, in this instance, also has outwardly extending, 
longitudinal projections or ridges 84 positioned between rows of the 
magnets 54 of the second plurality to provide a greater surface area and 
more heat transfer to the fluid. Of course, the projections 80 on the 
sleeve 56 and the ridges 84 on the sleeve 62 are not essential to the 
invention but do increase the rate of heat transfer to the fluid when they 
are employed. 
Cooling air is provided for the second plurality of magnets. Accordingly, 
an annular cooling passage 86 is formed between the outer surface of the 
outer sleeve 62 and the inner surface of the housing 50. The ends of the 
housing 50 are open and a central portion of the housing has a transverse 
outlet opening 88. An elbow fitting 90 communicates with that opening and 
a flexible outlet hose 92 is connected to the fitting. Referring to FIG. 
1, the hose 92 communicates with a manifold 94 from which an intake 
conduit or line 96 extends to the inlet of the compressor 14. 
Cooling air or fluid is also provided for the first plurality of the 
magnets 48. For this purpose, the end frame 26 has an inlet opening 98 
communicating with a hollow chamber 100 in the bearing mount 44. The mount 
44 has a plurality of slanted passages 102 which communicate with a 
passage 104 formed between the inner surface of the first sleeve 56 and 
the outer surface of the rotor 46. The passage 104 communicates with 
slanted passages 106 and a chamber 108 in the bearing mount 40. The 
chamber 108 connects through the opening 36 with an outer collector or 
manifold 110. A fitting 112 in the manifold 110 is connected to a flexible 
outlet hose 114 which communicates with the manifold 94. 
When the compressor 14 is operated, it draws fluid through the intake line 
96. Cooling fluid is thereby drawn through the passage 86 from the outer 
ends of the housing 50 and through the hose 92. This air cools the region 
of the magnets 54 of the second plurality. Cooling fluid is similarly 
drawn through the central opening 98 in the end frame 26 where it flows 
through the passage 104 past the magnets 48 of the first plurality and to 
the manifold 110 and the hose 114. Thus, the preheated cooling fluid 
enters the compressor 14 at an elevated temperature. From here it is 
compressed and heated somewhat further and supplied to an intake line 116. 
The compressed fluid then flows through the manifold 64 and through the 
passage 72 between the sleeves 56 and 62. The fluid, now at a high 
elevated temperature in pressure, is supplied from the end manifold 
chamber 70 through an outlet line 118 to the rock drills 18. There can be 
a plurality of fittings and lines around the manifolds 64 and 66, of 
course. 
Slightly modified heat exchange means are shown in FIGS. 6-8. In this 
instance, an inner sleeve 120 has a plurality of annularly extending 
ridges 122 with larger projections or ears 124 and smaller projections or 
ears 126. The ears 124 have openings 128 through which a portion of the 
fluid being heated can pass. An outer sleeve 130 has a plurality of 
longitudinally-extending ridges 132 thereon extending between rows of the 
outer plurality of magnets with the ears 124 extending into the interior 
of the ridges 132. 
Various modifications of the above-described preferred embodiments of the 
invention will be apparent to those skilled in the art, and it is to be 
understood that such modifications can be made without departing from the 
scope of the invention, if they are within the spirit and the tenor of the 
accompanying claims.