US2671037A - Method of washing dishes or the like - Google Patents

Description

March 2, 1954 E. s. STODDARD 2,671,037

METHODS OF WASHING DISHES OR THE LIKE Fiied Sept. 10, 1949 2 Sheets-Sheet 1 IN VEN TOR.

EDGAR S. STODDARD ATTYS.

' Patented Mar. 2, 1954 Maroon QE'WASH N SLH fi on THE BIKE Edgar S. stoddardhlierwynr 111;. assignon-to Gen,-

e cir Q mna a e/ unatic at Ne Yor Application September 10, IiMQ, Serial No. 114,956

, I The present invention relates to methods dishes, or the like. aconventional dishwashing apparatus, the liquid employed in the vatforb'oth washing" and rinsing purposes is hot water; and the dishes may be subjected to a primary washing step am ithen a secondary washing step, followed by a primary rinsing step and then a secondary rinsing step, the individual steps consuming predetermined time intervals established by a program controller incorporated in the apparatus; At the conclusion of each step, the used cl' argeof hot water contained" in the vat is drained therefrom, and then a fresh charge of hot water isintrodllccd into the vat to be used in carrying the succeeding step Normally a charge of detergent is introduced into the charge of hotwater-contained in the vat at the begirming of; the primarywashing step; while the secondary washingstep is carried out without the addition of a new charge of detergent, since a small residuum of the initial charge of detergent is present in the" vat following drain- ,i i pf the used charge of hot water at theconof: the primary washing step, This residis present in the vat as a result ofa small nortion ofthe used charge of hot water adhering to the dishes-andto the rack supporting the dishes and remaining inthe joints the walls gtjt'he vat and inthe drain mechanism connecting'the lower portion of the vat to the associated drain Qonduit." Both. the" primary rinsing step and th ondary i s n s e carried (o usin only the charges of fresh hot water in order positively to eliminate anyfilms of detergent from; the dishes Ultimately, the dishes n ay be subjected to a blast of hot an order to. effect a drying action thereupon.

While, thisimethod of washing dishes is highly satisfactory when soft water is employed, it is not entirely successful when hardwater is employed due to: the presence therein or the carbonates ofca'lcium and magnesium Specifically, the dishes, after being dried, are somewhat streaked or spottedand are thus robbed oftheir natural luster and sparkle. This; spotting is especially noticeable on glassware, and particularly on- Stemware, the spots having a; white: or,

grayish, outline of irregular configuration.

efieet ma he d tec sin sle th fqrmo a general discoloration of. the glassware. even in those, areas having, only slightly hard water.

ii yhilethe.provisionloiwater oit ningequipm nt whims. (011M725) in the plumbing preceding the dishwashlng ap paratus in: hard water localities is helpful in: re; ducing the rate at which this progressiue im pairment of the luster of. the glassware pros coeds, it doesnot. prevent the; ultimate impair,- ment noted, and the equipment does not. work satisfactorily without. frequent attention with particular reerencetorecharging In studying this problemit has been, discovered that this spotting of the glassware is directly traceable to: the drying thereon of rather large droplets of rinsing water, containing calcium carbonate and other hard watercomponents. following the secondary or final; rinsing step, and that this spotting may be. prevented by elimimating the-dropletsfrom the glassware. immedi ately following the secondary or final rinsing step preceding drying, even though hard water is employed. Further, it hasv been discovered that this objective may be achieved by introducing a suitable synthetic wetting agent into the. hot water contained in the vat in the secondary or final rinsing step, whereby the surface tension of the water is sufficiently reduced to cause it to run freely from the glassware so that no water droplets of any appreciable size remain on the glassware at the conclusion of the secondary or final rinsing step' and preceding drying ofthe glassware.

In carrying out t s method it is preferred that a liquid synthetic wetting agent be employed and that anexcess charge thereof be introduced into the charge of hot'water' contained in the vat in the-primary rinsingstep so that the desired effect is also achieved in this step. Then when the secondary or final rinsingstepis carried out, a sufiicient charge of the wetting agent will-be'pres'ent in the charge .of-hot water con.-

"tained in the vat, since a residuum of the initial excess charge of the synthetic wetting agent is present in the vat following draining of the ,used chargeof hot water at the conclusionof the primaryrinsing step, this residuum being present in. the vat due to the circumstances previously noted- 1 Acccrdingly,it is ageneral object of the -present invention to provide an improved method of washing dishes, or the like, that preserv'iestlie natural luster and sparkle thereof and prevents streaking and spotting thereof incident to dryins- Another object of; the invention is to provide a method of washing dishes, or the l-ikefthat in- ,1 e u es a mp o d rinsing. st e p oY hot water-'centaining a' synthetic wetting agentl' F r er ailuresarde t ic r m-noes particular arrangement of the steps of the method, whereby the above-outlined and additional operating features thereof are attained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawings, in which Figure 1 is a front elevational view, partly broken away, of dishwashing apparatus in which the method of the present invention may be carried out; Fig. 2 is a vertical sectional view of the dishwashing apparatus, taken in the direction of the arrows along the line 2-2 2, illustrating the front door in its open position and the dish-supporting rack in its withdrawn position, wherein it is carried by the front door; Fig. 4 is an enlarged side elevational view of the synthetic wetting agent receptacle that is carried by the dish-supporting rack, as illustrated in Figs. 2 and 3; Fig. 5 is an enlarged plan view of the synthetic wetting agent receptacle shown in Fig. 4; and Fig. 6 is an enlarged front elevational view, partly in section, of the synthetic wetting agent receptacle shown in Figs. 4 and 5.

Referring now to Figs. 1 and 2 of the drawings, there is generally illustrated automatic dishwashing apparatus ID that is preferably of the character of that disclosed in the copending application of Edgar S. Stoddard, Serial No. 105,618, filed July 19, 1949, now Patent Number 2,635,941, and incorporating a wetting agent receptacle and embodying structure for carrying out the method of the present invention. The dishwashing apparatus I is of the gasketlessdoor front-opening type including a cabinet I! housing a substantially vertically disposed ,vat |2, the cabinet I! and the vat |2 having substantially aligned front openings that are closed by a front door H3. The front door I3 is pivotally mounted adjacent to the lower edge thereof within the lower portion of the vat l2 and is movable between a substantially vertical closed position and .a substantially horizontal open position. .Also, the dishwashing apparatus H comprises movable rack structure |4 that is adapted to support dishes, and other utensils, within the vat l2 for washing purposes, the rack structure I4 being movable into and out of the vat l2 through the front openings when the door l3 occupies its open position. An impeller I5 is arranged within a sump l6 formed in the lower portion of the vat I2 and is rotated by an associated electric operating motor H for the purpose of producing a washing action within the vat |2 when the door l3 occupies its closed position and washing liquid is contained in the sump 16. More particularly, the impeller I5 is rotated in the counterclockwise direction as viewed from the top of the vat l2 in order to produce an upward swirl of the washing liquid or the rinsing liquid through the rack structure l4 supporting the dishes and other utensils, whereby the washing liquid or the rinsing-liquid is thrown upwardly into bombarding relation with the dishes supported by the rack structure I4 and then falls downwardly back into the sump Hi to be recirculated.

For the purpose of supplying washing liquid or rinsing'liquid to the vat l2, there is provided an inlet conduit connected to a suitable source of washing liquid or rinsing liquid, such, for example, as a hot water tank. The inlet conduit 28 communicates with the inlet port of an inlet valve 2| of the solenoid controlled type; and the outlet port of the inlet valve 2| communicates with a conduit 22 that is connected to a spraying device 23 arranged in a depression 25 formed substantially centrally within the top wall of the vat I2. The inlet valve 2| is of the fast-opening, slow-closing type, being governed by an associated clashpot so as to prevent water hammer in the plumbing communicating with the inlet conduit 2G. The inlet valve 2| is normally biased into its closed position, and when the solenoid 2 thereof is energized, it is operated into its open position in order that the hot water may be supplied from the inlet conduit 28 to the spraying device 23, whereby the hot water is sprayed downwardly in a rotating swirl by the spraying device 23 from the top of the vat l2 through the rack structure l4 and accumulates in the sump I6. Subsequently, when the solenoid 2| of the inlet valve 2| is de-energized, the inlet valve 2| is moved slowly from its open position into its closed position in order to cut off the supply of hot water from the inlet conduit 20 to the spraying device 23.

For the purpose of controlling the retention of washing liquid or rinsing liquid in the sump [6, there is provided a drain mechanism 30 of the solenoid controlled type. The drain mechanism 30 comprises a flexible conduit 3|, one end of which communicates with a drain fixture 32 provided in the lower portion of the sump I6, and the other end of which communicates with a drain conduit 33 that is connected via a trap, or the like, not shown, to drain plumbing, not shown. The flexible conduit 3| is normally biased by its weight into its lower portion in order to place the interior of the sump I6 into free draining communication with the drain conduit 33 so that any washing liquid or rinsing liquid accumulating in the sump It runs through the flexible conduit 3| into the drain conduit 33; and when the solenoid 3e thereof is energized the flexible conduit 3| is elevated into its upper portion in order to cut off the free draining communication between the interior of the sump may be retained in the sump l5.

ing liquid or rinsing liquid from the sump i6.

For the purpose of effecting drying of the dishes and other utensils supported by the rack structure I4 within the vat l2, there is provided a heating unit or element 40 that is preferably of the sheathed resistance conductor type. The heating element 40 is disposed in the lower portion of the vat I2 :below the rack structure 14 and in surrounding relation with respect to the impeller l5 so that air blown by the blades of the rotating impeller l5 contacts the heating element 40 and then moves upwardly through the rackstructure l4 into contact with the dishes and other utensils supported by the rack structure M in the vat l2. The lower portion of the door l3 carries a detergent cup 4| opening toward the interior of the vat |2 that is adapted to receive a charge of detergent. Preferably the detergent that is employed in the detergent cup 6| is of the type sold under the trade name Calgonite that comprises about 40 per cent sodium hexametaphosphate and 60 per cent sodium meta-silicate 1 As best shown in Fig. 3 therack structure I4 is removable as a whole fromthe door l3 in its been Peesitie'n the eoinpri'ses va vrower dishreek t2 tied a detachable upper dishrack as. The upper dishreclg #3, in turn, comprises an outer marginal section 44 ehd an inner detachable central section 4'5 hlso the central portion of the lower dishr'ack 42 carries a perforated silverware oas- Ret l6. Normally, the plates and other large dishes; are ermngea in the 'lowerflishrackli'; and the siliz'erwar'e 'alrrimjged in the basket 46. Also, the taps and saucers are normally 'arraJnged -i-n the outer marginal section '4} of the upper .dish en; {33; While the drinking glasses tumblers, and thelike, are normally arreneefi inthe centrallisecnan E5 of the Kipper dishrack 13. Finally, the central portion of the central sectionlii of the up- ,per dishrack 13 comprises an upwardly eitend ing ptstenjtiauy cylindrical open-work element 4.1 disfob'sed substantially directly below the sprayin device when the raekstruetu e M occupies Tits fnofrhel p'ositionjin the 'vet 12 which Veentrell .0551- iinderfelerh'ent l! carries .a wetting agent rece'iit'a'cleT'll. Thus'w henlthe rack structure I4 ciifiie's its normal. position in the 'vat T2 the wetra "adjacent to the spraying device .23 for a In' irpos'e mere ruuy gexpl ineu hereih'aiter.

best "s een in Figs. lto 'fi fin'clusive,the Syn- Ttli'tic 'iiitftih'g a'giit recepteeie 50 comprises a isulis'th htiall-y 'dylfiidfidell "may '51 provided with a eiitiell'y icirciilel'r liiiiged top cover 52, the 2 theupper'mrtronicf cover 52, the valve .elernent fi'belngmountefl fer Fihellyfthe ree'epteae 5lfeom prises msiibstantmHy-m sneped "tubeor siphon f'device l gm-ojbiit'ih'g through'zthe upperportidn of the-cylindrieel side wel1r5l ,-'-the siphon element sfi l including leg M disposed within the :cylindrical ibodyaSl endear-ejectingdownwardly and-terminating rad- :isee'enmo 'the bottom wall' @thereof andem legii=63 Hisensed:exteribrlyiof thecylindrical bodyt lend firojecting 5 downwardly below ithe whet-tom wall thereof. As'v the hot' waiterfissaccumulated inane receptacle '50 the head of liquid therein rises unt iiigtegerit'iecptacle'iifl is disposed directly bilow til it reaches a level indicated generality at.

whereby a predetermined quantity of liquid has been accumulated in the receptacle 50. The'liguid then flows between the legs '62 and $3 of 5 the siphon device 61 falling through the leg 68 and producing a siphon action between the legs 53 and 62 in a. well-known manner, whereby substantiallyth'e "entire liqnid contents-of the -reee ptable '50 is discharged by the siphon device 6 into-the vat 12. Thus it will be understood that when a. predetermined quantity ef liquid is eclcumulated within the receptacle 50 that substratetia'lly the entire liquid contents thereof is eutematicall y discharged therefrom' bythe sip'h0n; levice ti"! into :the Wet "1-2 which arrangement is utilized for a purpose more-fully explained here- *ina'fter.

The synthetic wetting agent that may =be employed in the receptacle 50 may be of any suit- Mile txpe although it preferable that fit he {in 'thetorm of a liquid, and-it i-has -'bee n found *that fa fgreait variety "of 'the sulfuric acid esters of the Iiigherfla'tty acids are admirably suitedtc this end. For examples, sodium lauryl sulfateend octzdecyl sodium sulfate are quite satisfactory. filso, the long cheiin sul'fonates rare suitable and 's'o'dium' lauryl *s iltonate "and oeta'deeyl sodium sul-fcnate have -'been found *toibe satisfactory. "chemical compositions of *these synthetic wetting agents "form no part -01 -the present in- 'viention end-any isyntheticwetting egent-"iseuit- -e'ble thatipossesses'the cheracteristic oi redueing the" surface "tension of hot water sufificientl yto cause -the *hot water montacting the*dishes and r lessware to run*rreely end quickly therefrom ;in --jorder-*to"prevent the'presenceofiairlyflargexiiplets of rinse water *on the dishes and -glesswe-re following the secondary-or fina-M'insi-ng step, and preceding drying, as explained more ,ful-lfihere inetter.

'Fen the purpose deflecting-coordinated, opera,- tion of -the vmious-"ccntrol" elements incorporgated d-ishwashing'trpparatns I D "inorder to aceemplish-a-'-complete 'eyele -of operationfithereils incorporatedwherein-an electric -c,on;trol circuit andprog ra rn controller rof it-he-eharacter'of that eis'close'd inthecoperrding application of Doug-les Iii-ismiaseriamos-egeoe; filedMey 7;=1-'94,9,. erms circu'it *eentro1 arrangement itnclu'desz a mfogram eoritroller ef the timerrtypedndicatedgenerally ttt-ti end-*fiisposed="irrithempper left hendjfiront insertion of thefelpperetus itbetween theadj ecent harid side' wall of the cabinet H en'd the hBJnd-Sifi8"W ai11 -Df'ithe'Vat 12,4. eneasuringeoil'or relay 12 disposed in the-flower efi left-herld from-r pertierr of theTaDPara'tus {B hettteen the-adjacent--'1eft herrd' sideiwa'll of jt-he cebinet' l I and the a dj eeerfi't left-hand side 'wall the' b ottom weill of thewat w and controlled-*hy "fiihe movements' 'of' the -front door ts. err-h 1 bgram contrcllerfll comprises an-felectric drive mttorfinot shown, "of -'the'-"timer: typeysirch tor -fexam"pl e,v as :a "Telechron motor, switching structure; not howni an an 'operetineislieftrthe iiefxtendslthroujehtheifrontwell of "thewhinetggl a flla-iidxsupnorts a notataihle eontro'l. knob'1;1j4.. .,that see-operates iwithhnelindicia inlets 1.5 ithat isedi- ,trectl mountedeediecentstheretc unonuthe Kent ':.'splratee3:5;:; .the windieie @notednbein v I wheeler spac deep rterelatien- :sD .ieoursemt. circuit control arrangement also includes the electric operating motor ll, the operating solenoid 2| of the inlet valve 2!, the operating solenoid 38' of the drain mechanism 38, and the electric heating element 40; and finally the circuit control arrangement includes a source of current supply that may be of 115 volts 60 cycle A. C.-

The details of the connection and arrangement of the circuit network in order to accomplish a complete washing cycle in the dishwashing apparatus is form no part of the present invention, and in the interest of brevity only the overall cycle of operation of the apparatus ID will be described with particularity.

In order to prepare the dishwashing apparatus ID for a cycle of operation, the dishes, glassware and other utensils are appropriately loaded into the rack structure hi; and a. predetermined charge of the liquid synthetic wetting agent mentioned is placed within the body 5! of the receptacle 50 through the open top thereof while the cover 52 occupies its open position. The cover 52 is then returned to its closed position with respect to the open top of the body 5|; and it may be assumed that the valve element 55 cccupies an adjusted position with respect to the cover 52 so that the liquid contents of the wetting agent receptacle 50 will be discharged'by the siphon device 6i during the primary rinsing step, as explained more fully hereinafter. The rack structure It is then pushed forwardly into the vat I2 into its normal position, whereby the cover 52 of the wetting agent receptacle 50 is disposed immediately below the rotary spraying device 23. A charge of the detergent noted is then placed in the detergent cup 4! provided in the lower inner wall of the door [3; and the door 13 is moved from its open position into its closed position.

The rotatable control knob '14 is then rotated from its Off position into its On position initiating operation of the program selector H and the electric control network. Specifically, at this time the program selector Tl initiates operation of the operating motor I! and initiates operation of the timer motor incorporated in the program selector 7!. The operating motor I! rotates the impeller i5 in the counterclockwise direction as viewed from the top of the vat l2; and the timer motor drives the control knob 14 continuously in the clockwise direction. as viewed in Fig. 1, at a predetermined rate and ultimately back into its Oil? position. After an elapsed time interval of approximately 90 seconds, the program controller H efiects energization of the inlet valve solenoid 2i, whereby the inlet valve 2| is operated from its closed position into its open position so that washing liquid may he supplied from the supply conduit 20 to the spraying device 23. The washing liquid is sprayed downwardly from the spraying device 23 into the vat i2 and through the dishes supported by the rack structure It and accumulates in the sump 16 from which it is drained through the drain mechanism 30 directly into the drain conduit 33 since the drain mechanism 30 occupies...

ing device 23 enters the wetting agent receptacle 5!) and is accumulated therein, along with the liquid wetting agent already in the receptacle 50. Approximately 30 seconds after the inlet valve 2! is thus operated into its open position, the program controller 'i'l energizes the solenoid 30' of the drain mechanism 3i whereby the drain mechanism 30 is operated from its draining position into its non-draining position so that the washing liquid is accumulated in the sump I6. At this time the washing liquid accumulating in the sump I6 is caught by the blades of the impeller l5 and is flung upwardly through the rack structure it and the dishes supported thereby against the walls of the vat i2 and the door l3 and again returns to the sump l6.

The supply of washin liquid from the spraying device 23 continues and as the quantity of washing liquid accumulating in the sump 16 increases, the load imposed upon the impeller I5 is gradually increased, the current drawn by the motor ll being gradually increased and metered by the measuring coil or relay 72. When a predetermined quantity of washing liquid accumulates in the sump 15 a correspcnding predetermined load is imposed upon the operating motor ll, whereby the current metered by the measuring relay 12 reaches a predetermined value. When this current traversin the relay I2 reaches the predetermined value mentioned, indicating that the vat i2 now contains a full and predetermined quantity of washing liquid, the measuring relay 12 operates and effects de-energization of the solenoid 2i i the inlet valve 2|, whereby the inlet valve ii is slowly returned from its open position into its closed position. Shortly thereafter the inlet valve 21 is completely closed cutting off the supply of washing liquid from the supply conduit 28 to the spraying device 23.

Approximately 45 seconds after the drain mechanism 39 is operated into its non-draining position, the program controller ll further opens the circuit for energizing the solenoid 2! of the inlet valve 2 I, thereby providing a timed arrangement for effecting the return of the inlet valve 2i into its closed position in the event this result has not already been brough about by operation of the measuring relay '52 within the &5 seconds period mentioned.

The primary washing step is thus initiated upon the operation of the drain mechanism so into its non-draining position, and continues for a total time interval ofapproximately 330 seconds; and within this time interval and in response to the accumulation of a predetermined quantity of washing liquid in the sump it, the charge of detergent contained in the detergent cup 5| is introduced into the washing liquid contained in the vat 52 in order that the primary washing step may be effective to remove grease and other foreign materials from the dishes supported by the rack structure Hi. The arrangement for introducing the detergent is disclosed in the copending application of Forrest A. Walker, Serial No. 57,448, filed October 30, 1948, and is based upon the accumulation of a predetermined quantity of washing liquid in the sump it during the primary washing step, whereby the washing liquid accumulating in the sump it is flushed or washed into the detergent cup ii carried by the inner wall of the door 13 causing the detergent contained therein to be washed into the body of washing liquid contained in the vat l2. This introduction of the detergent into the washing liquid conanew ,9 tained in- .the vat-4.2 is accomplishedshortly. .101! lowing theloperation of the drainv mechanism 311 into its non-draining ,position'initiating. the beginning of the primary washing step sothat the detergent is present in the washingl-iquid during alsubstantial part of the time intervalof the pri-. mary washing step.

Atthe conclusion of the pr nary washing step the program controller 1| opens the circuit for. energizing the solenoid 3d of the drain mechanism 38, whereby the drain mechanism 39 is returnedfrom its non-draining position into its draining position so that the washing liquidand the carried detergent contained in the sump .l fi is drained therefrom in a very short interval of time; and approximately 45 seconds after the drain mechanism 38 is operated into-its drainin position, the program controller 11 again closes the circuit for en'rg-izing. the solenoid 21 of; the inlet valve 2!, whereby washing liquid is again supplied to the spraying device 23 and is again sprayed downwardly into the vat 1-2. Approximately seconds after the inlet'valve 2i isoperated into its open positionthe program controller 1-! recloses the circuit for energizing the solenoid 33' of the drain mechanism 30, whereby the drain mechanism 30 is operated into its non-draining position in order to initiate 'a secondary washingstep.

The secondary washing step proceeds in the manner ofv the primary washing step described above; however, without the addition of ,another charge of detergent since a residual amount of the initial charge of detergent remains in the vat l2 from the primary washing step. This residuum of the detergent-is presentxintheivat 12 since a small portion of the charge or washing liquid contained in 'the'vat i2 during the primary-wa'shing step remain therein due to" adherence to the dishes and'the rack structure 14 and dueto its presence on the wall structure of the vat l2 and inthe drain mechanism 30. Specificallmthe inlet valve 2 is subsequently operated into-its closed position undenthe control of the measuring relay 12 dependent upon theload upon the operating motor 17, or under the control of the program controller H; all in the mannerpreviously explained. In-any case, after a time inter; valor approximately 45 seconds following opera tion of the drain mechanismcfl into its nondraining positionthe inlet valve 2| is operated into its closed position. At this time the inlet valve 2i occupies its closed position and the drain mechanism 3! occupies its non-draining position, whereby the secondary washing step continues in the manner previously explained. As the washing'liquidissprayed downwardly from the spray-'- ing device 23' into the vat .l 2 during. 'thesecondary washing step. additional liquid is accumulated in the wetting agent receptacle 58. f The secondary washing step continues for a time'i-nterval of approximately 330 seconds following operation of the drain mechanism into its -non-draining position; whereupon the program selector ll efiects the return of the drain mechanism 3!; into its. draining position as previously explained.

'The washing liquid accumulated in the sump it is drained into the drain conduit 33 in the manner previously explained in a very short time interval; and approximately 45 seconds after-the drain mechanism 3B is operated into its drain ing position the program selector fllagain 0perates the .inlet' valvelzl' into its open position. The rinsing liquid is then sprayed downwardly It) into .thevat. 1.2.. by the spraying device. 23 for a time interval ofapproximately 10,.Seconds; whereupon the program controller TI again returns .thedrain mechanism 30 into its non-draining position, initiating a primary rinsing step.

Theprimary rinsing step proceeds in a mannerv substantially identical to the primary washing step described above, whereby the inlet valve 2 is subsequently operated into its closed position under the control of the measuring relay l2 dependent upon the load upon the operating motorv H, or under the control of the program selector .H; all in the manner previously explained. In any case. after a time interval of approximately 45 seconds following operation of the drain mechanism '30 into its non-draining position, the inlet valve .21 is operated into its closed position. The primary rinsing step continues for a time interval of approximately .90 seconds following the operation of the drain mechanism 36 into its non-draining position, whereupon the program selector H effects the return of the drain mechanism 30 into its draining position.

As the rinsing liquid is sprayed downwardly from the spraying-device 23 into the vat i2 during the primary rinsing step, additional liquid is accumulated in the wetting agent receptacle 58, whereby a predetermined total head of liquid is accumulated in the receptacle 50 causing the siphon device 6! to operate automatically to discharge substantially the entire liquid contents of the receptacle 5.3 into the vat i2. The charge of wetting agentthus introduced into the charge of ..rinsing liquid contained in the vat 12 reduces the surface tension thereof so that the rinsing liquid runs freely from the dishessupported by the rack structure l4.

The rinsing. liquid accumulated in the sump .ifi'is drained into the drain conduit 33 at the conclusionv of the primary rinsing step in the manner previously explained in a short time interval; and approximately 45 seconds after the drain mechanism 30 is operated into its draining position, the program selector H reoperates the inlet valve 2| into its openposition. The rinsing liquid is sprayed downwardly from the .spraying device 23 into the vat l2; and approximately 10 seconds following operation .of theinlet valve'2i into its open position the program selector. H effects operation of. the drain mechanism 30ln'to its non-draining position in order to initiate a secondary rinse step.

The secondary rinsing step proceeds in-a manner substantially identical to the primary rinsing step described. above except that no additional charge of synthetic wetting agent is in trocluced into the charge. of rinsing liquid con.- tained in the vat .12. .The inlet valve '21 is subsequently operated into its .closed'position under the control of the measuring relay 1.2 dependent upon the load uponthe operating motor IT, or under the control of the program selector l I; all in the manner previously explained. In any case, after a time interval of approximately 45 seconds following operation of the drain. mechanism so into its non-draining position, the inlet valve .2! is operated intoits closed position. The secondary rinsing step continues for a time interval oiapproximately seconds following the operating of the draining mechanism 3B into its nonedrainingj position, whereupon thelprogram selector H eifects the return of the drain 'meche anis'ni so into. its draining .positionj i "T h e rinsingliciuid -.accumulated in the sump V when - ll. I is drained into the drain conduit 33 in the manner previously explained in a short time interval; and approximately 45 seconds after the drain mechanism 30 is operated into its draining position, the program selector H closes the circuit for energizing the heating element 40, whereby heat produced by the heating element 48 is circulated in the vat I2 by the blades of the impeller It: in the form of an upwardly directed blast of hot air into contact with the dishes supported by the rack structure I 4.

Since a residuum of the synthetic wetting agent is present in the body of rinsing liquid contained in the vat I2 during the secondary rinsing step, due to the circumstances previously noted, the surface tension of the rinsing liquid is sufficiently reduced so that it readily runs off the dishes supported by the rack structure I4 at the conclusion of the secondary rinsing step. Accordingly, at this time when the drying step is initiated there are no droplets of rinsing liquid of any considerable size adhering to the dishes supported by the rack structure M. The hot air circulated in the vat I2 by the impeller is directed into contact with the dishes supported by the rack struc ture I4 effecting a drying action thereupon, and is thence circulated back into contact with the heating element 40 by the impeller I5.

This action constitutes an initial drying step and is continued for a time interval of approximately 1200 seconds, whereupon the program selector II opens the circuit for energizing the operating motor I! while retaining closed the circuit for energizing the heating element 46. Accordingly, the operating motor I! stops, arresting the rotation of the impeller I5, while the generation of heat by the heating element 40 continues. Thus drying of the dishes supported by the rack structure I 4 continues through a final drying step after operation of the impeller I 5 has been arrested. The final drying step continues for a time interval of approximately 600 seconds, whereupon the program controller II interrupts the circuit for energizin the heating element 46, as swell as the circuit for operating the timer motor incorporated in the program selector H.

At this time the control knob I4 has been rotated from its on position in the clockwise direction back into its oil? position; operation of the program selector II has been arrested; and the cycle of operation of the dishwashing apparatus I 6 has been completed. Thus it will be understood that when the manual control knob 14 of the program selector H is rotated from its off position into its on position in the clockwise direction, further operation ofv the program selector II is automatically continued under the control of the associated timer motor, whereby the cycle of operation of the dishwashing apparatus I0 is carried out automatically, a time interval of approximately 2970 seconds being required.

During the operation of the dishwashing apparatus I 0 in the timed cycle above-described, the door I3 must be retained in its closed position in order to retain the door switch I3 in its closed position, since the door switch I3 occupies an interlock position in the control circuit network; and any time the door I3 is operated into its open position, the door switch I3 is operated into its open position arresting the cycle of operation of the dishwashing apparatus Hi. Final- 1y, at the conclusion of the timed washing cycle, the dishes supported by the rack structure I4 have not only been thoroughly washed and rinsed, but they have also been subjected to a drying action. Subsequently, the door I3 may be moved from its closed position into its open position, and the rack structure [4 may be moved out of the vat over the door I3 so that the dishes may be removed from the rack structure I4 and placed in a kitchen cabinet, or the like, if desired.

In the operation of the washing apparatus I0, the dishes, glassware, etc., supported by the rack structure [4 are subjected to the initial and the final drying steps, following the secondary rinsing step, under conditions such that there are no droplets of rinsing liquid thereon during the drying actions. This effect is accomplished by virtue of the presence of an adequate amount of synthetic wetting agent in the charge of rinsing liquid during the secondary rinsing step, an excess charge of synthettic wetting agent being introduced into the charge of rinsing liquid during the primary rinsing step as a matter of preferred technique. Since the dishes, glassware, and the like, undergo the drying action without the presence thereon of the water droplets mentioned, it is not critical that the washing and rinsing liquids employed in the dishwashing apparatus It may comprise hard water that'has been merely heated to the proper temperature in a hot water tank, or the like, without any water softening treatment. Specifically, since the dishes, glassware, etc., are subjected to the drying actions noted in the absence of the water droplets mentioned, they are not spotted or streaked at the conclusion of the drying step or subjected to the gradual discoloring efiects that normally proceed from the utilization of hard water in dishwashing apparatus of this character.

In view of the foregoing, it is apparent that there has been provided an improved .method of washing dishes, or the like, that may be readily carried out in a known type of automatic dishwashing apparatus, as well as improved equipment that may be readily installed into the automatic dishwashing apparatus mentioned in order to convert it to carry out the present method.

While there has been described what is at present considered to be the preferred embodi ment of the invention, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. The method of washing dishes, or the like, arranged in an enclosing vat comprising introducing a first body of hot water into the vat, introducing an excess charge of detergent into the first body of hot water, circulating the first body of hot water in the vat into bombarding relation with the dishes for a time interval in order to efieet primary washing of substantially all of the soil therefrom, draining the first body of hot water from the vat, introducing a second body or" hot water into the vat, circulating the second body of hot water in the vat into bombarding relation with the dishes for a time interval in order to efiect secondary washing of the small residual soil therefrom, draining the second body of hot water from the vat, introducing a third body of hot water into the vat, introducing an excess charge of synthetic wetting agent into the third body of hot water, circulating the third body of hot water in the vat into,

bombarding relation with the dishes for "a" time interval in order to effect primary rinsing of substantially all of the detergent therefrom, draining the third body of hot water from the vat, introducing a fourth body of hot water into the vat, circulating the fourth body of hot water in the vat into bombarding relation with the dishes for a time interval in order to effect secondary rinsing of the small residual detergent therefrom, draining the fourth body of hot water from the vat, the last-mentioned rinse water containing a sufiicient quantity of the synthetic wetting agent to reduce the surface tension thereof so that substantially all of the last-mentioned rinse water drains freely and quickly from the dishes, and finally retaining the dishes in the vat for a time interval in order to effect evaporation of the small residuum of the last-mentioned rinse water thereon and the consequent drying thereof.

2. The method of washing dishes, or the like, arranged in an enclosing vat comprising introducing a first body of hot water into the vat, introducing an excess charge of detergent into the first body of hot water, circulatin the first body of hot water in the vat into bombarding relation with the dishes for a time interval in order to effect primary washing of substantially all of the soil therefrom, draining the first body of hot water from the vat, introducing a second body of hot water into the vat, circulating the second body of hot water in the vat into bombarding relation with the dishes for a time interval in order to effect secondary washing of the small residual soil therefrom, draining the second body of hot water from the vat, introducing a third body of hot water into the vat, introducing an excess charge of synthetic wetting agent into the third body of hot water, circulating the third body of hot water in the vat into bombarding relation with the dishes for a time interval in order to effect primary rinsing of substantially all of the detergent therefrom, draining the third body of hot water from the vat, introducing a fourth body of hot water into the vat, circulating the fourth body of hot water in the vat into bombarding relation with the dishes for a time interval in order to effect secondary rinsing of the small residual detergent therefrom, draining the fourth body of hot water from the vat, the last-mentioned rinse water containing a sufficient quantity of the synthetic wetting agent to reduce the surface tension thereof so that substantially all of the last-mentioned rinse water drains freely and quickly from the dishes, and finally circulating hot air in the vat in the form of a blast into contact with the dishes for a time interval in order to effect evaporation of the small residuum of the last-mentioned rinse water thereon and the consequent drying thereof.

3. The method set forth in claim 1, wherein the synthetic wetting agent consists essentially of an ester of a higher fatty acid, in which the fatty acid portion of the molecule contains from 12 to 18 carbon atoms.

4. The method set forth in claim 1, wherein the synthetic wetting agent consists essentially of a sulfuric acid ester of a higher fatty acid, in which the fatty acid portion of the molecule contains from 12 to 18 carbon atoms.

5. The method set forth in claim 1, wherein the synthetic wetting agent consists essentially of sodium lauryl sulfate.

EDGAR S. STODDARD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,476,909 Moore Dec. 11, 19 3 1,529,168 Cleveland Mar. 10, 1925 1,662,496 Forsgard Mar. 13, 1928 1,847,256 Nielsen Mar. 1, 1932 2,109,575 Parsons Mar. 1, 1938 2,226,096 Halsey Dec. 24, 1940 2,385,264 Ferris Sept. 18, 1945 2,390,757 Voris Dec. 11, 1945 2,509,003 Lathrop May 23, 1950

Claims (1)

1. THE METHOD OF WASHING DISHES, OR THE LIKE, ARRANGED IN AN ENCLOSING VAT COMPRISING INTRODUCING A FIRST BODY OF HOT WATER INTO THE VAT, INTRODUCING AN EXCESS CHARGE OF DETERGENT INTO THE FIRST BODY OF HOT WATER, CIRCULATING THE FIRST BODY OF HOT WATER IN THE VAT INTO BOMBARDING RELATION WITH THE DISHES FOR A TIME INTERVAL IN ORDER TO EFFECT PRIMARY WASHING OF SUBSTANTIALLY ALL OF THE SOIL THEREFROM, DRAINING THE FIRST BODY OF HOT WATER FROM THE VAT, INTRODUCING A SECOND BODY OF HOT WATER INTO THE VAT, CIRCULATING THE SECOND BODY OF HOT WATER IN THE VAT INTO BOMBARDING RELATION WITH THE DISHES FOR A TIME INTERVAL IN ORDER TO EFFECT SECONDARY WASHING OF THE SMALL RESIDUAL SOIL THEREFROM, DRAINING THE SECOND BODY OF HOT WATER IN THE VAT, INTRODUCING A THIRD BODY OF HOT WATER INTO THE VAT, INTRODUCING AN EXCESS CHARGE OF SYNTHETIC WETTING AGENT INTO THE THIRD BODY OF HOT WATER, CIRCULATING THE THRID BODY OF HOT WATER IN THE VAT INTO BOMBARDING RELATION WITH THE DISHES FOR A TIME INTERVAL IN ORDER TO EFFECT PRIMARY RINSING OF SUBSTANTIALLY ALL OF THE DETERGENT THEREFROM, DRAINING THE THIRD BODY OF HOT WATER FROM THE VAT, INTRODUCING A FOUTH BODY OF HOT WATER INTO THE VAT, CIRCULATING THE FOURTH BODY OF HOT WATER IN THE VAT INTO BOMBARDING RELATION WITH THE DISHES FOR A TIME INTERVAL IN ORDER TO EFFECT SECONDARY RINSING OF THE SMALL RESIDUAL DETERGENT THEREFROM, DRAINING THE FOURTH BODY OF HOT WATER FROM THE VAT, THE LAST-MENTIONED RINSE WATER CONTAINING A SUFFICIENT QUANTITY OF THE SYNTHETIC WETTING AGENT TO REDUCE THE SURFACE TENSION THEREOF SO THAT SUBSTANTIALLY ALL OF THE LAST-MENTIONED RINSE WATER DRAINS FREELY AND QUICKLY FROM THE DISHES, AND FINALLY RETAINING THE DISHES IN THE VAT FOR A TIME INTERVAL IN ORDER TO EFFECT EVAPORATION OF THE SMALL RESIDUUM OF THE LAST-MENTIONED RINSE WATER THEREON AND THE CONSEQUENT DRYING THEREOF.

Images