US3068877A - Dishwasher - Google Patents

Description

J. W. JACOBS Dec. 13, 1962 DISHWASHER 2 Sheets-Sheet 2 Filed Sept. 12, 1958 INVENIOR. Fly. 2 James W Jacobs BY 5 g z His Attorney United States Patent Ofiice 3,i68,877 DISHWASHER James W. Jacobs, Dayton, Ohio, assignor to General Mo- This invention relates to a domestic appliance and more particularly to an improved door construction for a dishwasher.

Two aims of the design engineers in the dishwashing art are to minimize the amount of steam or vapor which escapes to the area surrounding the dishwasher and to speed the dishwashing cycle. In the current dishwasher designs two drying systems are prevalent, one wherein the access door for the dishwasher is opened at the beginning of the drying cycle and the other wherein the door is closed throughout the dishwashing cycle. Maintaining the door in a closed condition provides the advantage of eliminating the exhaust of steam from the dishwashing chamber and therefore eliminates the damage arising when condensate forms on the relatively cool surface surrounding the dishwasher. However, the drying portion of a dishwashing cycle is generally longer in those machines incorporating the closed dishwashing chamber during drying. It is the purpose of this invention to include the desirable condensate-free features of a closed drying system in a dishwasher having a door construction designed to expedite the drying cycle.

Accordingly, it is an object of this invention to provide a dishwasher door having means for condensing moisture from the air within the dishwashing chamber.

It is also an object of this invention to provide-a door construction for a cleaning machine which includes an air cooled condenser.

A more specific object of this invention contemplates the incorporation of a condenser in a dishwasher door having a first conduit in communication with a dishwashing chamber and a second conduit in communication with the atmosphere and in heat exchange relationship to said first conduit.

It is an additional object of this invention to provide the condenser last described with a blower system having a single prime mover for actuating an impeller in the first conduit for recirculating vapor from a dishwashing chamber and an impeller in the second conduit for circulating cooling air from the atmosphere.

It is a further object of this invention to provide a vapor conduit for a door-mounted condenser which will permit gravity flow of condensate to the sump of a dishwashing chamber for removal to drain.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a fragmentary side sectional view of a dishwasher suitable for use with this invention and taken along line 11 of FIGURE 2;

FIGURE 2 is a front elevational view of a dishwasher illustrating the counterfiow passages of the door-mounted condenser; and

FIGURE 3 is a sectional view of the condenser taken along line 33 of FIGURE 1.

In accordance with this invention and with reference to FIG. 1, a dishwasher having a top wall 12, a rear panel 14 and a base portion 16 is adapted to include a dishwashing chamber shown generally at 18. The dishwashing chamber 18 is a generally box-like receptacle having a depressed bottom defining a sump 20. The

dishwashing chamber 13 has also an access opening 22 in the front wall thereof. Closing the opening 22 is a dishwasher door, shown generally at 24. The door 24- may be hinged and latched to the side panels of the dishwasher 10 in any conventional manner and is adapted to be opened by a handle 26. In order to insure a watertight connection between the dishwashing chamber 18 and the door 24, a gasket 28 may be provided and arranged peripherally about the opening 22.

Although this invention is not to be limited to a particular type of dishwasher, for purposes of illustration the dishwasher 10 is shown provided with a spray tube 36 rotatably supported at 32 on a bracket 36 and at 34 on a spray header 42. During a dishwashing cycle, water collecting in sump 20 enters a motor-driven pump arrangement, shown generally at 38, and is recirculated to the spray tube 36 through a conduit 4% the water being so pumped having a swirl imparted to it in the spray tube inlet header member 42. This swirl imparts a rotational movement to the spray tube 39, thereby causing jets of water to issue from spray tube ports 44 over the surfaces of the dishes 46 that are carried in conventional support racks 48. Also within the dishwashing chamber 18 is a heater 5i) which is energized at the conclusion of the wash portion of the cycle to raise the temperature within the dishwashing chamber 18 to dry the dishes therein. It is, of course, possible to energize the heater 50 periodically throughout the dishwashing portion of the cycle to maintain desired higher temperatures within the chamber 18. At the conclusion of a dishwashing cycle, a drain solenoid 52 may be energized to open valve 54 to permit the pump 38 to remove water from the sump 20 to any suitable remote drain. The dishwashing cycle may be initiated by a start button 56 to energize a timer 58 which thus programs sequentially the desireddishwashing cycle. For additional details on the dishwasher mechanism outlined broadly hereinabove, reference may be had to the patent to Abresch et al., 2,808,063 issued October 1, 1957.

During the period that water is being circulated from the sump 29 to the spray tube 30, considerable steam is evolved, depending, of course, on the temperatures of the washing fluids being circulated. When the surfaces of the dishes and utensils carried by the racks 48 have been sufliciently cleaned and rinsed, it is then desirable to effect a rapid drying of the cleansed dishes. If the door 2 closing the steam or vapor-filled dishwashing chamber 18 were open, the steam and vapor thus released would flow into the surrounding area to condense on the first cool surface encountered. If this surface happens to be wood, as for instance, the under side of a countertop overlying a built-in dishwasher, a deterioration would be noticed in the surface over a period of time. It is therefore desirable to keep the door 24 ciosed during the drying operation of the dishwashing cycle and the applicant has provided a novel condenser or dehumidifier to be mounted within the door 24 for removing moisture from the vapor within the dishwashing chamber a the dishes are being dried.

A construction is provided for the dishwasher door 24 to permit the installation of a heat exchanger, shown generally at dd, therewithin. The door 24 is formed with a front panel 62, a rear panel 64- and a peripheral wall having a top wall portion 66, and a bottom wall portion 68. In FIG. 1 the thickness of door 24 has been exaggerated to emphasize the features of the applicants heat exchanger 69. It should be obvious that a door of conventional design may be used in accordance with the concepts of this invention to efiect a condensing arrangement within the door. To permit a circulation of the moisture-laden vapor or steam through the condenser 60 from the drying chamber 13, a vapor duct or conduit 74 is provided. The duct 74 has a condenser inlet opening 76 and a condenser outlet opening 78 leading from and to the dishwashing chamber 18, respectively. The vapor duct 74 is generally vertically extending and includes a bottom wall 8% graded generally toward the dishwashing chamber 18 for reasons to be described hereinafter. With reference to FIG. 3, the vapor duct or conduit 74 is provided with a plurality of heat transfer fins 77 which are generally Z-shaped and spot-Welded as at 82 to the interior sides of duct 74. Thus, vapor entering vapor duct inlet 76 is caused to pass between the heat transfer fins 77 as it traverses through the condenser 66 The duct 74 may be fabricated of any sheet metal suitable for rapid transfer of heat.

Cooling air is provided the condenser 69 from the atmosphere surrounding the dishwasher it). A cooling air conduit or duct 84 is included also between the front panel 62 and the rear panel 64 of the dishwasher door 24. An inlet 86 to the duct 84 is formed in the bottom wall portion 68 of door 24, while an outlet 88 is laterally spaced from said inlet in the bottom wall 68 to permit the cooling air to return to the atmosphere after passing over the condenser 60. Surrounding the vapor duct 74 in transverse relationship to heat transfer fins 77 is a second set of heat transfer fins 9%. The fins 90 may be spot-welded to the outside of duct 74 in the same manner as were fins 77 welded within the duct. The cooling air passage or duct 84 is directed over the exterior fins 99 and around the vapor duct 74 before exhausting from the cooling air outlet 83. In this manner the cooling air does not come in contact with the 'dishes being washed and sanitary conditions are thus maintained.

The circulating air system utilized in drawing vapor from within the dishwashing chamber 18 and cooling air from the surrounding atmosphere will now be more fully set forth. The cooling air duct 84 is provided with an enlarged inlet chamber 92 for receiving a fan having a motor 94 and a cooling air impeller 96 supported on a motor shaft 98. The motor or power shaft 98 is arranged to project through a bushing or bearing 1% into an outlet header portion 102 of the vapor duct 74. In this location a second impeller 104 for vapor is carried on the shaft 98. With the motor 94 operating in one direction, the impeller 104 is so formed to draw moisture-laden vapor from the chamber 18 through the vapor duct inlet 76 and into the condenser 60. At the same time impeller 96 draws cooling outside air into duct 84 through inlet 86 and forces this air into counterflow moisture condensing relationship with the vapor in duct 74.

In operation, the dishwasher door 24 may be opened and the racks 48 slidarbly removed from the dishwashing chamber 18 to permit loading of the dishwasher. When the racks 48 have been returned to their position within the dishwashing chamber 18, the door 24 is closed and latched, the gasket 28 effecting a water-tight seal between the door and the opening to the dishwashing chamber. A conventional timer mechanism 58 may then cause a predetermined quantity of water or cleaning fluid to be admitted to sump 29 through any suitable water filling device (not shown). The timer may then energize the pump 38 for circulating the hot fluid from the sump through the conduit 44) to the spray tube 30 from whence it is forcefully ejected over the surfaces of the dishes 46. At the conclusion of this dishwashing or jet scrubbing portion of the cycle, the solenoid 52 is energized to open a drain valve 54 and the pump 38 removes the soiled washing fluid from the sump to drain. Since the applicants invention pertains to a dishwasher wherein the complete dishwashing cycle is accomplished in a closed chamber, the heater 50 may then be energized to raise the temperatures within the dishwashing chamber 18, thereby to initiate a drying operation. At substantially the same time, motor 94 is energized to initiate the condensing feature of this invention. Impeller 104 will cause the moisture-laden vapor to be withdrawn from the dishwashing chamber 18 into the condenser 60. Within the condenser the walls of duct 74 and the heat transfer fins 76 and 9% are below the dew-point of the circulating vapor due to the flow thereacross of cooling outside air in duct 84.. Moisture will thus condense from the circulating Vapor and will fall by gravity to the lower wall 80 of duct 74. This condensate will flow into the chamber 18 and consequently into sump 20 where it may be removed to drain by the action of a continuously operating pump 38. Of course, the pump 33 need not be operating throughout the drying cycle and the condensate may be permitted to collect in the sump or run by gravity to drain. 1

It should now be seen that a novel condensing system has been provided for a dishwasher which will effect a rapid drying operation without the need for exhausting moisture-laden vapor or steam on the surfaces surrounding the dishwasher. Furthermore, the outside air utilized to dehumidify the dishwashing vapor and expedite drying is never permitted :to come in contact with the sanitized dishes.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. A dishwasher including fixed top, bottom, rear and side walls enclosing a dishwashing chamber, a generally hollow door forming substantially the entire front wall and closable for enclosing the dishwashing chamber, a substantially horizontal spray tube rotatable about a horizontal axis and extending forwardly from and substantially perpendicular to the rear wall, means for supporting dishes above and below said spray tube, said bottom wall forming a sump below said support means and having a sump opening selectively connected .to a drain,

means connected to said sump opening for supplying cleansing fluid to said spray tube for spraying said dishes in said support means whereby fluid sprayed on said dishes gravitationally returns to said sump, heating means for drying the dishes with said door closed by vaporizing the .fluid on said dishes after the dishes have been sprayed, said door comprising a front panel, a rear panel in parallel spaced relationship to said front panel and overlying said sump, a bottom panel and a fluid vapor condenser between said front and rear panels, means between said door and said chamber walls for sealing the inside of said chamber from the outside of said chamber, said condenser including a vapor conduit and an outside air duct partially enclosing said vapor conduitand in transverse counterfiow relationship to said vapor conduit, a

first set of heat transfer fins in said vapor conduit, a second set of heat transfer fins in said outside air duct in engagement with said vapor conduit and in transverse relationship to said first set, said vapor conduit extending 'vertically in said door andhaving an inlet opening in said rear panel connected on one side of said sealing means to said chamber near the top of said chamber and an outlet opening in said rear panel connected on said one side of said sealing means to said chamber above said sump and below saidinlet opening to permit gravity drainage of condensate from said vapor conduit to said sump for selective distribution to drain, said outside'air duct having an outside air inlet and an outside air outlet in said bottom panel of said door on the other side of said sealing means, said vapor conduit and said outside air duct having juxtaposed wall portions, a first impeller in said vapor conduit on one side of said juxtaposed wall portions, a second impeller in said outside air duct on the other side of said juxtaposed wall portions, and a single prime mover in said door between said front and rear panels having a shaft extending through said juxtaposed wall portions and operable with said heating means for actuating said first impeller in said vapor conduit for initiating a circulation of fiuid vapor between said chamber and said vapor conduit from said inlet open ing to said outlet opening to vaporize fluid from said dishes and for actuating said second impeller in said outside a-ir duct for initiating a circulation of outside air between the atmosphere and said outside air duct from said outside air inlet to said outside air outlet for condensing moisture from said fluid vapor, whereby the relative humidity of said =fiuid vapor is decreased and the drying of said dishes is expedited.

2. A dishwasher including walls enclosing a dishwashing chamber and defining an access opening, a generally hollow door forming substantially one entire wall and closable for enclosing the dishwashing chamber, means for spraying in said chamber, means for supporting dishes in exposed relationship to said spray means, one of said walls forming a sump below said support means and having a sump opening selectively connected to a drain, means connected to said sump opening for supplying cleansing fluid to said spray means for spraying said dishes in said support means whereby fluid sprayed on said dishes gravitationally returns to said sump, heating means for drying the dishes with said door closed by vaporizing the fluid on said dishes after the dishes have been sprayed, said door comprising an outer panel, an inner panel in parallel spaced relationship to said outer panel and overlying said sump, an intermediate panel interposed between said panels along one edge thereof and a fiuid vapor condenser between said outer and inner panels, means between said door and said chamber walls for sealing the inside of said chamber from the outside of said chamber, said condenser including a vapor conduit and an outside air duct partially enclosing said vapor conduit and in transverse counterflow relationship to said vapor conduit, a first set of heat transfer fins in said vapor conduit, a second set of heat transfer fins in said outside air duct in engagement with said vapor conduit and in transverse relationship to said first set, said vapor conduit extending through said door and having an inlet opening in said inner panel connected on one side of said sealing means to said chamber near the top of said chamber and an outlet opening in said inner panel connected on said one side of said sealing means to said chamber above said sump and in gravity flow relationship to said inlet opening to permit gravity drainage of condensate from said vapor conduit to said sump for selective distribution to drain, said outside air duct having an outside air inlet and an outside air outlet in said intermediate panel of said door on the other side of said sealing means, said vapor conduit and said outside air duct having juxtaposed wall portions, a first impeller in said vapor conduit on one side of said juxtaposed wall portions, a second impeller in said outside air duct on the other side of said juxtaposed wall portions, and a single prime mover in said door between said outer and inner panels having a shaft extending through said juxtaposed Wall portions and operable with said heating means for actuating said first impeller in said vapor conduit for initiating a circulation of fluid vapor between said chamher and said vapor conduit from said inlet opening to said outlet opening to vaporize fluid from said dishes and for actuating said second impeller in said outside air duct for initiating a circulation of outside air between the atmosphere and said outside air duct from said outside air inlet to said outside air outlet for condensing moisture from said fluid vapor, whereby the relative humidity of said fluid vapor is decreased and the drying of said dishes is expedited.

References Cited in the file of this patent UNITED STATES PATENTS 2,105,692 Hunicke Jan. 18, 1938 2,596,622 Vannerus May 13, 1952 2,607,209 Constantine Aug. 19, 1952 2,675,628 ONeil Apr. 20, 1954 2,716,289. Lauck Aug. 30, 1955 2,717,320 Shoulders et a1 Sept. 6, 1955 2,859,755 Burke Nov. 11, 1958 2,918,068 Karig Dec. 22, 1959

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