US 3918479 A
A dishwasher in which the temperature of washing fluid and/or a load heating medium is elevated by the direction thereof into heat transferral contact with the electric drive motor that supplies the conventional pumping power. A split phase motor is employed having main and phase windings connected in parallel, and the entire motor is enclosed in an oil bearing jacket throughout which the oil is circulated over both the rotor and stator. A collar positioned near the rotor-stator gap directs oil flow in the gap reducing friction and wearing of insulation. Alternatively, a shaded pole type of induction motor can be used. Proper valving permits the wash fluid to flow to lower and/or upper spray arms and to a drain, and a flexible diaphragm or a reservoir provides for oil expansion in the jacket.
Claims available in
Description (OCR text may contain errors)
United States Patent [191 1 Perl 14 Nov. 11, 1975 HEAT SYSTEM FOR DISHWASHER 75 Inventor Richard L. Perl, Mansfield, Ohio  Assignee: The Tappan Company, Mansfield,
21 Filed: Dec. 11, 1972' 1] Appl. No.: 313,659
Related U.S. Application Data 1  Continuation-in-part of Ser. No. 195,197, Nov. 3
1971, Pat. No. 3,750,951.
 U.S. Cl. 137/340; 417/367; 310/61  Int. Cl. H02k 1/32; H02k 9/00  Field of Search 417/367, 366; 137/340; 310/61  References Cited UNITED STATES PATENTS 2,107,481 2/1938 Johnson 1. 417/367 2,321,126 6/1943 Breuer 417/367 3,576,378 4/1971 Hilmanowski 417/366 Primary E.\'aminer-Henry T. Klinksiek Attorney, Agent, or FirmDonnelly, Maky, Renner & Otto  ABSTRACT 'A dishwasher in which the temperature of washing fluid and/or a load heating medium is elevated by the direction thereof into heat transferral contact with the electric drive motor that supplies the conventional pumping power. A split phase motor is employed having main and phase windings connected in parallel, and the entire motor is enclosed in an oil bearing jacket throughout which the oil is circulated over both the rotor'and stator. A collar positioned near the rotor-stator gap directs oil flow in the gap reducing friction and wearing of insulation. Alternatively, a shaded pole type of induction motor can be used. Proper valving permits the wash fluid to flow to lower and/or upper spray arms and to a drain, and a flexible diaphragm or a reservoir provides for oil expansion in the jacket.
28 Claims, 3 Drawing Figures US. Patent Nov. 11, 1975 3,918,479
This is a continuation-impart of my copending patent application ser, O 195,197, filed Nov. 3, 1971 Now Patent 3,750,951. a a
This invention relates to a dishwasher apparatus and more particularly to a novel type of dishwasher construction in which utilization is made of the pump motor as a source of heat energy for elevating the water temperature for cleaning sanitizing and idrying purposes. I v
Conventional dishwasher configurations employ an electric resistance heating element as a source of power for elevating the temperature of thewash water and for aiding the drying portion of the cycle, such element consisting of a heater coil insulatively supported in the bottom of the dishwasher enclosure, requiring interconnection with the timing mechanism and provision for suitable interconnection wires and the like. The conventional motor is employed solely for pumping purposes typically being mounted outside the dishwasher housing and communicating with. an impeller arrangement in a sump section of the dishwasher chamber, developing 1 R losses in the windings and eddy current and the like losses in the core structure which heat energy is mostly lost outside the dish wa'sher housing.
A known form .of dishwasher construction which mounts the motor in a wet sump a'ttached tothe dishwasherltubie describedin US. Pat. No, 3,576,378 issued Apr. 27, 1971, to James R. Hilmanowski, teaching that motor cooling can be effectively established by a direct communication between the wash water and a portion of the motor structurefAnother form of dishwasher construction that heats the water by pumping same through'the pump motor which is encapsulated in epoxy to heat the liquid'is described in Us. Pat. No. 3,587,939 issued June 28, 1971, to Arne M Ny stu'en et al. These prior patents do not teach a high orderiof heating, and the epoxy used in the latter patent a poor thermal conductor as well as expensive.
When utilizing the motor for elevation of the wash water and drying air temperature numerous problems are encountered. End temperature of the water is significant, dependentin part upon the temperature of the water entering the dishwasher; the rate of elevationof the temperature isof importance in achieving a suitable level during the dishwasher cycle; large particles must be filtered to prevent clogging in'thepurnp chamber and around the motor; and consideration mustbe given to maintenance 'of the temperature at suc hlelevated level for a predetermined intervalof time to assure opf timum cleansing and sanitizing fun ctions. lt has been learned that whelnfsuch dual purpose ofthemotorii s r quired, i.e for pumping and for heating, consideration must be given to the typ'e'and configuration of motor employed and compromises must be resolved between v pumping power and the generation of'heating energy. An efficient utilization of such energy must be obtained requiring design configurations different from the conventional air c o oledtype of motor arrangement. in
view of the current stress on etiology, it alse is'irn portant to provide for conservation of building materials,
watei and energy while reducing pollutants to the envi ronment; and with an eye on ever increasing inflation it is important to reduce manufacturingcost generally.
Therefore, itis one object ofthis invention to proyide a new form of dishwasher in :which thermal ener g y from the pump drive motor ie employed for useful elevation of'ter'nperature of the wash in gor working fluid.'
It is another object of this invention to provide a new form of dishwasher in which the" drive motor serves a dual function and is located within the dish washer enclosure. 7
It is a further object of this invention to provide dishwasher apparatus with a substantially dry sump and having means'for directing the water into intimate contact witha drive motor. 7 .An additional object of this invention is the provision of dishwasher apparatus having various forms of mo tors as the power sou rce, wherein sufficient heat can be generated for useful temperature elevation purposes andtr ansferral of the heatto the working fluid is optimized. i I
' Still another object of thisjinventio'n is the provision of dishwasher apparatus in wh'ich'the wash liquid is heated as it passes in heat transferral relation with a fluid filled jacket surrounding the pump motor, with provision to accommodate excess fluid due to expansion thereof as the temperature increases.
Still a further object of this invention'is the provision of a pump motor for a dishwaslierapparatus, which pump motor is immersed in a fluid filled jacket and cir culates fluid in the jacket through the rotor andover the stator'while driving a pump mechanism external of the jacket. a v x v Still an additional object of this invention is the provision of a dishwasher apparatus with'a pump for pump ing water under pressure intothe dishwasher enclosure and to provide for nearly complete draining of water from the dishwasher cavity. n I
Theseand'other objects and advantages of the pres' scri'ption proceeds.
To the accomplishment of the foregoingand'related ends, the invention, then, comprises'the features here inafter fully described, thefollow'ing description and which the principals of the invention be employed. I
In the annexed drawing:
E10. 1 is an elevational view incross-section of the lower portion of a dis hwasher enclosure including a pump housing;
FIG. 2 is an elevational view in cross-section, partiallybroken away of the lower portion of a modified dishwasher enclosure including a portion of the pump housing; and l FIG. 3 a schematic one-line electri'ccircuit diagram for energizing and controlling a dishwasher.
Referring now to the drawing wherein like reference numerals refer to like elements'iri the several figures there is' shown in FIG. 1 one: embodiment of the invennt inve ntion will become apparent as the following detion including dishwasher l comprisinga tub 11 forming the dishwasher enclosure and a pump housing 12 associated with the enclosure. The pump housing 12 is a pan-like housing which may be molded or stamped as part of the dishwasher or may be an individual pump enclosure 13 supported in an opening 14 in the bottom of the tub 11 in sealed relation therewith.
A circular support plate 15 is secured at the upper portion of the pump housing 12 by screws 16, such support plate having a downwardly extending flange portion 17, and the inner edge 18 of the flange portion 17 forms a substantially circular opening to center the motor 19 within the pump housing 12. The support plate 15 formslpart of a separator 20 which also ineludes a removable strainer 21 with a handle 22, resting ona seat 23 of the circular support plate 15 and separating the pump housing 12 from the dishwasher enclosure or tub 11 for purposes of directing water flow therebetween while filtering same. Communication between the, tub ll of the dishwasher enclosure and the pump housing 12 is achieved by a plurality of ports 24 located in the downwardly extending flange portion 17 of the support plate 15 just outside the periphery of the motor v 19, the water flow which passes in intimate contact with a jacket 25 surrounding the motor being indicated by the dashed arrows 26 in FIG. 1. As the separator 20 provides a tortuous path for the water flow requiring same to pass throughthe openings 27 in the strainer 21, across the upper surface 28 of the motor jacket 25, and through the ports 24 in the flange portion 17, large particles not able to traverse the path are filtered from the water. i
The pumphousing 12 has a plurality of planar spacer support members 29 for supporting the motor 19 within the .pumphousing while permitting unrestricted water flow through the pump housing to a conventional impeller 30 for pumping through a high pressure cham ber 31 of scroll or volute form and valving chamber 32 to a standpipe arrangement 33 for distribution to a spray arm mechanism 34 in the dishwasher enclosure. The high pressure chamber 31 is formed by an upper wall portion 35 separating the heating area 36 from the drain pipe 57 or a seco ndse at 58 at an opening 59 to the standpipe arrangement 33, and a diverter flapper valve 60 rotatable about a shaft 61 to mate with a first seat 62 on a port63 leading to an upper spray arm standpipe (not shown) or a second seat 64 formed on the lower spray arm standpipe 53, although the diverter flapper 'valve may be eliminated if only one spray arm and standpipe are used. The valves 54, 60 may be spring biased cam operated valves, pinch valves. or the like, being operable in known manner for example, by
I under pressure. An apertured support member 65 pumping area 37 of the pump 38 and is adapted to rest on a seat 39 formed in the pump housing wall. The
lower wall 40 of the pump housing 12 forms the bottom of the high pressure chamber 31, and a pump outlet 41 connects the latter with the valving chamber32. The upper wall portion 35 conforms generally to the shape of the .impeller 30 having a central opening 42 to permit water flow through the impeller to the high pressure chamber 31. A divider wall 43 mates with a stainless steel plate 44 to separate the pump housing 12 from the, standpipe arrangement 33, and a standpipe drain opening 45 near the bottom of the divider wall is covered by a spring biased flapper valve 46 secured thereto by a screw 47. The stainless steel plate 44 may be secured at one end 48, for example by a screw 49 to thecircular support plate 15 and may be tapered at its other end 50 to mate with the divider wall 43. A hold down support 51 is also fastened to the circular support plate 15 by a screw 49 and to the motor jacket 25 for maintaining the motor 19 in position within the pump housing 12. The circular support plate 15 additionally may be formed with a portion 52 forming part of the lower spray arm standpipe 53.
forming an arbor is affixed to the top portion of the standpipe 53 providing a rotatable support for and communication with a reaction spray arm 66, the latter being mounted on the arbor for rotation thereabout under the impetus of the fluid under pressure and may be retained on the arbor by a cap 67, if desired. A deflector 68 in the arbor directs fluid from the standpipe 53 into the spray arm 66 for discharge through spray openings 69 into the dishwasher enclosure. The
spray arm 66 may be made from relatively inexpensive plastic, as it is not required to withstand the high temperatures developed by the electric resistance heating element used in conventional dishwashers, as described above. Similarly, because there is no localized high temperature heating, there is less damage to plastic dishes and the like.
The thermal source for elevating the water temperature in the dishwasher, as well as a'loa'd heating medium such as air for drying if desired, is the pump motor 19, which may be a uni-directional split phase type induction motor located within the pump housing 12 and isolated from the tub 11 portion of the dishwasher by the separator 20. The motor 19'c'onsists .of a stator 70 supported in the motor jacket 25, which may be stainless steel or other thermally conductive and corrosion resistant material. The stator 70 includes A drain flapper valve 54 in the valving chamber 32 Q is rotatable about a shaft 55 to abut a first seat 56 at the an iron core ring 71 formed of stacked laminations defining four poles circumscribed by windings 72 interconnected with themain 73 and phase or start 74 windings (FIG. 3) connected in parallel electrical relation for single phase power energization. Input power to the windings 73, 74 is received 'via leads 75 (only one of which isshown) passing through the pump housing 12 in a fluid tight connector 76, Such a split phase motor does not require the inclu s'ion of mechanical switching devices and the like for starting, and is capable of providing sufficient source of thermal energy; Additionally, because the motor is small, the pump housing '12 may be relatively small therefore requiring less water for dishwasher'operation than in conventional dishwashers. Also, since the impeller intake is located at a low point and because the valve 60 generally permits water to flow to only one spray arm at a time, the water requirements for the dishwasher may be further reduced. Whilea four pole motor has been shown and described, a two pole motor alternatively may be used;
The motor canister or jacket 25 has upper and lower portions 77, 78 crimped together, for example about an O-ring seal 79, and is substantially filled with fluid, such as transformer oil or other non-conductive liquid having suitable lubricating, electrical, and viscosity properties. The stator laminations in the iron core 71 are electrically insulated in known manner and abut the motor jacket 25 to facilitate heat transfer therebetween. The
stator may be generally circular or square in cross section, as desired and depending on the number of poles employed.
The rotor 80 of the motor 19 is centrally oriented within the motor jacket 25 and consists of a circular core or body 81 of stacked laminations mounted on a motor drive shaft 82, in turn supported for rotation about a longitudinal axis at upper and lower bearing housings 83, 84 in a dual bearing arrangement. The core 81 of the rotor 80 includes plural generally axial apertures 85 extending through the laminations adjacent the drive shaft 82 in the center of the core to provide a flow path for the oil through the interior of the rotor 80. The apertures 85 are sufficiently wide to provide little restriction to the oil flow, and a plurality of vanes 86, 87 at the top or. bottom of the rotor 80 assist to pump oil through the apertures and to circulate same throughout the jacket 25'. Although both upper and A lower vanes are shown, usually only one or the other would be used. Within and partially below the lower bearing housing 84 is a seal 88 to prevent the entry of water into the motor jacket 25 and the exit of oil from the jacket, while permitting connection of the drive shaft 82 to the impeller'30.
A collar 89 positioned near the gap 90 defined between the motor stator and rotor is formed by upper or lower substantially cylindrical barriers or dividers 91, 92 having plural openings 93, 94 about their circumferences and is positioned between the stator core 71 and the motor jacket upper and lower portions 77, 78. Although both upper and lower parts 91, 92 of the collar 89 are shown, usually only one or the other would be used. The collar 89 divides the jacket 25 into two chambers, the first containing the stator and the second containing the rotor, and controls oil flow in the gap eliminating excessive wearing or erosion of the stator insulation, the oil eliminating the possiblity of corrosion in the motor, and thereby increasing the life of the motor.
'The end 95 of the drive shaft 82 is threaded and is connected by a nut 96 to rotate the impeller 30 while the seal 88 maintains fluid isolation between the inside and outside of the motor jacket 25. The seal 88 includes a ceramic member 97 annularly disposed about the drive shaft 82 and supported against a rubber seal 98, gasket 99, and O-ring 100 in recess 101 in the impeller for rotation therewith. The upper surface of the ceramic member 97 is substantially planar and mates with the lower planar surface of a substantially annular graphite fitting 102 surrounding the drive shaft 82 but not connected thereto. The fitting 102 alternatively may be formed of ground carbon or other material having solid body with lubricant properties. A spring 103 surrounded on three sides by a rubber boot 104, which may abut the oute'rsurface and a flange portion 105 of the substantially annular graphite fitting 102 and a fixed seat portion 106 forming part of the lower bearing housing 84 urges the lower planar surface of the graphite fitting 102 into abutment with the upper surface of the ceramic member 97, suchas for example alumina. Thus, as the impeller 30 rotates, the ceramicmember 97 slides over the fixed graphite fitting 102, the abutting surfaces thereof providing a fluid tight seal for the motor jacket 25.
The impeller 30 consists of a thin housing 107 having a plurality of impeller blades 108 welded or formed on the interior thereof. In one form the impeller consists of a single molded part. The upper portion of the impeller is apertured for receipt of fluid and is secured to the motor drive shaft 82 as previously described. Upon rotation of the impeller 30, fluid is forced outwardly thereof into the high pressure or volute chamber 31 for delivery to the valving chamber 32, the standpipe arrangement 33, and one of the lower or upper spray arms. The drain flapper type valve 54 may be controlled to close the drain pipe 57 during the dishwasher washing, rinsing, or drying cycles and to open while the pump is operating for quick evacuation of the pump housing 12 and the tub 11 when desired.
It is significant to note that relatively thick laminations are indicated in both the stator 70 and rotor 80 of the motor 19 inasmuch as optimum pumping efficiency of the motor both by the impeller 30 and by the vanes 86, 87 is not the sole criterion but rather a compromise between same and the thermal energy generated so that both functions may be accomplished in the most efficient manner. Thus this form of structure is designed to introduce relatively high levels of eddy current flow. and hysteresisloss within the iron structure of the motor 19 and this :combined with 1 R loss in the windings 73, 74, which can be controlled in a known manner, can supply sufficient thermal energy for elevating the temperature'of the wash fluid to a desired level. Also, the number. of turns in the phase or start windings 74 may be increased or decreased from the usual number employed, thereby achieving a high power factor for the motor to provide for the most efficient use of current supplied thereto. The fluid circulating within the motor jacket 25 is in direct contact with all parts of the motor,-.i.e. the rotor and stator, and transmits heat therefrom to the jacket so that an optimumheat transferral relation to the water and/or the load heating, medium such as drying air can be achieved.
The fluid tight connector 76, through which the lead 75 passes for connection to the motor windings, is nonconductive and includes a first relatively rigid seal member 109 and a second relatively pliable seal member 110, which is an elastomer with proper electrical and resistant properties. The first seal member 109 is fitted on both sides of an opening 111 through the motor jacket 25 with an O-ring 112 positioned about the circumference of the opening. A compression plate 113 to which the motor winding lead 75 is attached is held in place against the first rigid seal member 109 by a flared hollow threaded rivet l 14, which in turn is connected to a drilledthreaded stud 115 having a power lead 116 connected thereto by a nut 1l7. The rivet 114 maintains the first rigid seal member 109 in position, while the second pliable seal member or elastomer is compressed into strong sealing relation with an opening 118 in-the pump housing 12 by force exerted between a further compression plate 119 and the first rigid seal member. The second pliable seal member or elastomer 110 must be capable of withstanding effects of the fluids on the both sides thereof. The rivet 114,
' stud 115, and compression plates 113, 119 are electrically conductive and together form an electrical'connection between the'power'lead 116 and the lead 75.
The oil within the motor jacket 25 expands when'its' temperature increases; and the hollow rivet 114, drilled stud 115, and an opening l20 in a cap 121 connect through a tube 122 to areservoir 123 for expanded oil. The reservoir 123 also provides an oil source to maintain the motor" jacket 25 in filled condition as the oil temperature decreases.
The dishwasher shown in FIG. 2 is similar to that in FIG. 1 except thereservoir 1 23has" been replaced by' a folded expandable diaphragm 124 fixed, for example, by screws 125 drilled into the upper surface 28 of the motor jacket 25 thereby providing an expandable reservoir chamber 126 (shown enlarged in dotted outline) for expanded oil as the latter increases in temperature during'motor I9 operationl The expandable reservoir chamber" 126 communicates-with the interior of the motor jacket 25through openings 127, and the drilled, stud described above in FIG. 1, may be replaced in this embodiment by a solid stud 128 threaded into a hollow rivet 114 for convenience of assembly. 5
i n electric power control circuit 129 for the dish washer apparatus shown in FIG. 3 includes a timer -finotor'and switching assembly 130 energized'from a power supply 131 through a switch 132, operable, for
example, either manually and/or automatically upon closure of thedishwasher door. A thermostat safety switch 133 is connected to break any possible electric circuit to the dishwasher apparatus in the event of an inadvertant excessive temperature rise, and a float switch 134 maycontrol operation ofa filling valve and /or drain valve 54 for-supplying and/or removing water from the dishwasher. As discussed above, the main 73 ing. It will be apparent that overall efficiencies in the cost and operationof the dishwasher are'enhanced both' by'the elimination ofthe requirement for a separate-heater elementand in theless stringent requirements for de'sign'of the motor. Still, further, it will :be clear that the teachings of this'inv'entionapply not only to dishwashers but to any device which requires the combination of a' thermal and mechanical source of power.
In operation the dishwasher 10 is electrically energizedand wash water is provided from a source (not shown). The motor 19 rotates the impeller 30 which i pumps the water into the valving chamber 32 for delivery to either theupper or lower standpipe and into the dishwasher tub I lthrough the'associated spray arm for washing. If an'upper standpipe is-used with an upper ter. If only one standpipe and one spray arm are used,
and phase or start 74 windings of the motor 19 are connected in parallel, and the valve controls l35 ,"for example foroperating the diverter flapper valve and the drain valve 54 are connected for energi'zation by the timer motor and switching assembly 130. Also, if desired, one or more thermal protectors or thermostats 136, 137 may be connected in'the motor circuit to'protect the latter from generating excessive heat;
While the invention has been described above as using a split phase motor, alternatively a shaded pole motor may be used. As in conventional, a portion of each pole of theshaded pole'motor is surrounded by a shading coil consisting of a short circuited turn of wire to cause a flux lag in the shaded portion and, as a result,
a rotating magnetic field for production of starting ity but the conventional split phase'rnot'o'r start switch or relay has also be en eliminated. r 4 I While'the ele'vatio'n'of'wash water-temperature is-of primary'significance, it will be clear that when the dishwasher is evacuated of water a heating effect-occurs upon the air therein while the motor 19is energized; and the impeller 30 pumps the heated air throughout the dishwasher enclosure to aid in drying" and sanitizthen the diverter valve may be eliminated.
As the motor 19 runs, heat is generated thereby due to'l R and eddy current losses. The apertures-'and vanes 86, 87 inthe rotating rotor 80 pumpthe transformer oil throughoutthe motorjacket 25 about the rotor and stator 70 removing heat therefrom. The oil flows through the openings 93, 94 in the upper or lower part 91, 92'of thecollar89, while the latterprevents oil from flowing only through the rotor to reduce wearing of the insulation on the-windings in the stator. As the transformer oil temperature increases, it expands, and
some of the expanded oil flows through the hollow rivet 114,-drilled stud and tube 122 into the reservoir 123 for storage. In the embodiment shown in FIG. 2, as
the oilexpands'itflows through the'openings 127 into filled with transformer oil with an air space left therein for expa'nsionof the transformer oil.
- During washing, wash water passes through the openings 24 in the strainer 21, which filters large particles therefrom, and flows along the upper,.side, and lower surfaces of the motor jacket 25 in intimate heat transferral contact therewith, while the heated transformer oil and the hot stator larn'inations'provide heat to the motor jacket. The wash water is thus heated and then flows into the'impeller 30 for pumping to one of the upper or lower standpipes for delivery into the dishwasher tub"11. Also, the waterin the pump housing damp's the motor noise to result in relatively quiet operatton. Sinceall the heat transferred to the water is developed by the motor 19, the dishwashervmay operate with a substantially dry sump, the only criterion for efficient operation being that sufficient water be used to maintain the pump housing 12 substantially filled during washin g'and rinsing cycles;
Betweenop'erating'cycles substantially all the water in the dishwasher'lO is removedz 'Drain ing is achieved by-rotatingthedrain flappernvalve 54 on the shaft 55 to a position against the valve seat 58, and the impeller then pumps water from the motor housing directly into the drain pipe 57; it is desirable to remove most of the water from the dishwasher, and therefore the flapper valve 46, which is normally biased closed to cover the standpipe drain opening 45 by the high water pressure occurring in the standpipe arrangement 33, opens by its own spring force since the pressure in the standpipe arrangement is relatively low when the drain valve 54 is in the drain positionfThe water from the standpipe arrangement then flows into the motor housing 12 through the standpipe drain opening 45 for pumping by the impeller 30 to the drain pipe 57.
The dishwasher control circuit 129 provides electric power from the power supply l3l, which may be an electrical outlet, to the dishwasher l 0.when the switch 132 is closed, for example upon closing the dishwasher door. The timer motor; and switching assembly 130, which may include a start button, provides electric power selectively to, the motor windings 72, 73 and to the valve controls 135, while the thermostat safety switch 133 and the float switch 134 protect the dishwasher from excess heat or excess water.
Comparative tests between .a conventional dishwasher heater system using a 750 W heating element and pump motor combination and the heating system of .the instant invention using a split phase type of motor in an oil filled-jacket indicates that higher rates ofheat rise of washing fluid can be obtained'in the in-- stant apparatus for equal quantities of input power. Fluid temperatures suitable for washing and drying purposes are readily achieved and maintained even though it is expected with the apparatus of the instant invention that a somewhat higher than-conventional fluid 145 and l65-F. with desired sanitizing temperature.
attained in l0l 5 minutes, assuming adequate suppl water temperature. 1 t
Using'the apparatus of the instant invention, the dishwasher rnay be desighed without the'normally required sump space, a'll'the wash water-passing into the pump housing 12 and immediately being pumpe'd'through the the pump outlet 41 thr oughthe valving arrangement 33 to only one spray arm at a time for delivery into the dishwasher tub 11 to clean dishes therein. Thus, the amount of water required 'has'been proportionately'reduced resulting in less, environmental pollutionJ-It has also been foundthat the elimination of'the electric resistance heating element and the use of the simplified pump motor disclosed, has resulte'd in the elimination of some formerly required mechanical components; Since, spot or localized temperatures in the tub"ll are not raised as high as those occurring in the conventional dishwasher using an electric resistance heating element, it is not necessary that the spray arms and other accessories used in the tub be of expensive heat resistant materials. Thus, manufacturing costs can be reduced as much as one-fourth relative to conventional dishwashers.
The embodiments of the invention in which an exclusive property or privilege is claimed are described as follows:
l. Dishwasher apparatus comprising a tub portion and a pump housing portion; means within said housing portion for distributing a washing liquid therein to said tub portion for the washing of dishes or the like in the latter; a motor within said housing portion, said motor having a statorand a relatively movable rotor, and a jacket enclosing said stator and said rotor, said jacket being substantially filled with an electrically nonconductive second liquid, said motor being positioned in said housing portion to permit the washing liquid to pass in heat transferral contact with said jacket for appreciably elevating the temperature of the washing liquid for washing and sanitizing; and pump means operatively connected with said rotor for pumping said washing liquid under pressure to said distributing means.
2. Dishwasher apparatus as" set forth in 7 claim 1 wherein said second liquid comprises a dielectric liquid.
3. Dishwasher apparatus as set forth in claim 1 wherein said rotor comprises a body portion mounted for rotation about a longitudinal axis, said body portion having apertures therethrough extending in adirection substantially parallel to said longitudinalaxisJvhereby upon energization of said motor said rotor rotates about said longitudinal axis thereby pumping said second liquid throughout said jacket.
4. Dishwasher apparatus as set forth in claim 3 further comprising vane means positioned on said rotor for facilitating pumping said second liquid throughout said jacket. I
5. Dishwasher apparatus as set forth in claim 1 further comprising a gap defined between said rotor and saidstator, and collar means positioned proximate said gap for controlling liquid flow. therein.
6. Dishwasher apparatus as' set forth in claim 5 wherein said collar means comprises divider means for dividing said jacket into first and second chambers, said first .chamber including said stator and said second chamber including said rotor, and openings in said divider means for permitting liquid flow between said prises diaphragm means formingat least a .portion of said jacket, whereby expansion of said second liquid causes said diaphragm means to'expand thereby in? creasing the volume of said jacket.
9, Dishwasher apparatus as set forth in claim wherein said means for receiving and holding co'm prises reservoir means and means coupling said reservoir means with said jacket to permit liquid flow therebetween, whereby as said second liquid expands in said jacket a portion of saidsecond liquid flows to said reservoir means and as said liquid in said jacket contracts a portion of said second liquid in said reservoir means flows to said jacket.
10. Dishwasher apparatus as set forth in claim 7 wherein said means for receiving and holding comprises a gas fluid spaced within said jacket, whereby expansion of said second liquid compresses gas in said gas space thereby producing additional volume for said expanded second liquid.
11. Dishwasher apparatus as set forth in claim 1 further comprising bearing means in said jacket, drive shaft means journaled in said bearing means for supporting said rotor for rotation, said jacket having an opening therein and said drive shaft means having an end extending through said opening, and means for claim 1 fursealing said openingat said end for preventing said washing liquid from entering said jacket and said sec ond liquid from escaping said jacket, said means for sealing including resilient means for urging said means for sealing closed.
l2. Dishwasher apparatus as set forth in claim 11 wherein said means for sealing comprises ceramic means having a planar surface and solid means with lubricant properties having a planar surface, one of same being rotatable with said drive shaft means and the other of same being fixed relative to said jacket, and said resilient means being positioned for urging said respective planar surfaces into abutment to form a fluid tight seal therebetween.
l3. Dishwasher apparatus as set forth in claim 11 wherein said pump means comprises impeller means fixed to said end of said drive shaft means.
14. Dishwasher apparatus as set forth in claim 1 further comprising means for coupling said motor to a source'of electric energy.
15. Dishwasher apparatus as set forth in claim 14 wherein said means for coupling comprises an electrically conductive'me'a'ns extending-from a location exterior of said pump housing to a location interior of said motor jacket through respective openings therein, electrically non-conductive pliable seal means substantially encircling said electrically conductive means at least proximate one of said openings, and compression means for maintaining said seallmeans in position sealing said opening.
16. Dishwasher apparatus as set forth in claim 15 wherein said electrically conductive means comprises hollow fluid conductive means, and further comprising means associated with said jacket for accommodating said second liquid as the latter increases in temperature including reservoir means coupled in fluid communication with said electrically conductive means, whereby as said second liquid expands in said jacket a portion thereof flows to said reservoir means through said electrically conductive means and as said second liquid in said jacket contracts a portion thereof in said reservoir means flows to said jacket.
17. Dishwasher apparatus as set forth in claim 1 further comprising filter means for filtering-the washing liquid prior to contact with said jacket.
18. Dishwasher apparatus as set forth in claim 1 wherein said means for distributing comprises at least one standpipe means for directing the washing liquid from said pump means to said tub portion.
19. Dishwasher apparatus as set forth in claim 18 further comprising drain means for conducting the washing liquid from said pump means from said dishwasher apparatus, said drain means including a drain outlet means and valve means for selectively opening and closing a liquid flow path to said standpipe means and said drain outlet means.
20. Dishwasher apparatus as set forth in claim 19 further comprising further valve means for coupling said standpipe means with said pump means when said drain valve means closes said standpipe means from said pump means, whereby when said pump means is operative to pump the washing liquid to said drain outlet means, the washing liquidin said standpipe means flows through said further valve means into said pump means and to said drain outlet means,
21. Dishwasher apparatus as set forth in claim 1 wherein said motor comprises an induction motor.
22. Dishwasher apparatus as set forth in claim 21 wherein said induction motor comprises a split phase induction motor having start windings and main windings, said start windings and said main windings being electrically connected in permanent parallel relation.
23. Dishwasher apparatus as set forth in claim 21 wherein said induction motor comprises a unidirectional induction motor.
24. Dishwasher apparatus as set forth in claim 21 wherein said rotor includes a plurality of apertures therein providing a flow path for said second liquid interiorly of said motor, and said stator and said rotor comprise stacks of relatively thick laminations to increase eddy current losses therein for facilitating generation of heat by said motor.
25. Dishwasher apparatus as set forth in claim 1 further comprising spacer support means for supporting said jacket'in said housing and providing space for the washing liquid to flow over said jacket.
26. An electric motor comprising a substantially liquid filled jacketga relatively fixed stator positioned in said jacket, rotatable rotor means positioned in said jacket means for rotation about a longitudinal axis, a gap formed between said stator and said rotor means, and means for circulating the liquid throughout said jacket including apertures extending through said rotor means in a direction substantially parallel to said longitudinal axis, whereby upon energization of said electric motor-said rotor means rotates about said longitudinal axis thereby circulating the liquid throughout said jacket. 7 I
27. An electric motor as set forth in claim 26 further comprising vane means positioned on said rotor means for facilitating circulation of the liquid throughout said jacket. v 1
28. An electric motor as set forth in claim 26 further comprising collar means for controlling liquid circulation in said gap.