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Publication numberUS3903909 A
Publication typeGrant
Publication dateSep 9, 1975
Filing dateOct 15, 1971
Priority dateOct 15, 1971
Publication numberUS 3903909 A, US 3903909A, US-A-3903909, US3903909 A, US3903909A
InventorsGeorge J Federighi, Tore H Noren
Original AssigneeGeorge J Federighi, Tore H Noren
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Apparatus for washing, rinsing, and sterilizing dishes
US 3903909 A
Abstract  available in
Images(5)
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Claims  available in
Description  (OCR text may contain errors)

United States Patent 1191 Noren et al.

[ APPARATUS FOR WASHING, RINSING,

AND STERILIZING DISHES [76] Inventors: Tore H. Noren; George J. Federighi,

both of 1350 Donner Ave, San Francisco, Calif. 94124 221 Filed: om. 15,1971

211 Appl.No.: 189,711

[52] US. Cl 134/58 D; 134/95; 134/98; l34/lOl; 134/103; l34/l [3 [51] Int. Cl. B08B 3/02 [58] Field of Search 134/58 D, 95. 98, I00, l34/l0l,103. 113

[56] References Cited UNITED STATES PATENTS 2,228,205 l/l94l Dwyer 134/98 2,592.884 4/l952 Fox ct al 1 1 134/95 X 2 740,4l5 4/!956 Federighi ct aim. 134/58 D 2,963.029 12/1960 Bock 134/58 D 549,294 12/1970 Kerr et al.. l34/58 D 3,707.l60 [2/1972 Query l34/95 X Primary Examiner-Robert L. Bleutge Attorney, Agent, or FirmWilliam R. Piper 5 7 ABSTRACT Dishwasher having a timed cycle for a complete washing, rinsing and sterilizing of dishes in which the dish 1 1 Sept. 9, 1975 washing cycle portion extends for a predetermined time period after which the motor and water pump stops and the drain valve opens to drain the wash water from the machine. Then the fresh water fill valve opens after the drain valve has remained open for a predetermined time period and the machine will cause this fresh water to flow under the city water pressure only through the discharge reservoir and the upper and lower wash and rinse arms for flusing the interior of the dishwashing machine and this flushing water will then flow out through the drain. The drain valve then closes and the fresh water fill valve will remain open until about 2 gallons of water are delivered to the machine. While the fresh water valve is open, a predetermined quantity of a wetting agent and chlorine are added to the fresh water entering the ma chine. The motor and pump are started when the fresh water valve is opened and when the water pressure reaches about 20 pounds per square inch, a water pressure switch closes the fresh water fill valve. The motor will be shut off for about 1 second at this point to relieve any air lock from the pump. The motor and pump will then be operated for the power rinse cycle and at the end of this cycle a detergent valve will open for about 3 seconds to admit a predetermined quantity of detergent into the machine preparatory for the next dishwashing cycle and then the machine will stop opcrating thus completing the timed cycle for one full operation of the machine.

5 Claims, 10 Drawing Figures PATENTED SE? 91975 SHEETIUFS m ATTORNEY PATENTEUSEP 91975 3.903809 saw 2 (IF 5 INVENTOR. TORE H. NOREN I GEORGE J. FEDERIGHI 7 1 g L? BY ATTADMCV snman g INVENTOR. TORE H. NOREN BY GEORGE J. FEDERIGHI ATTORNEY w E 6 llll PATENTEUsEP 91375 3 903,909

SHIT 5 [1F 5 INVENTOR. TORE H. NOREN BY GEORGE J. FEDERIGHI ATTORNEY APPARATUS FOR WASHING, RlNSlNG, AND STERILIZING DISHES BACKGROUND OF THE INVENTION l. Field of the Invention It has been determined that dishes can be sterilized during the power rinse cycle by using a predetermined quantity of chlorine in the water rather than spraying the dishes with rinse water heated to about 180 F. This results in a saving of both water and the extra heating normally required for raising the water temperature to about l80 F. A further saving of fresh heated water results when at the end of the power rinse cycle, a predetermined quantity of detergent is added to the water preparatory to using this same water in the next dishwashing cycle for the next group of soiled dishes that are to be washed. All the operator needs to do is to remove the washed and sterilized dishes from the machine after the machine has stopped operating and then place in the machine the next group of soiled dishes. The starting switch can be closed and the machine will then automatically go through the complete cycle of washing, rinsing and sterilizing operations already described.

2. Description of the Prior Art The patent to John B. Tuthill, US. Pat. No. 2,718,481, issued on Sept. 20, l955, on a method of washing dishes, discloses in the graph containing the time schedule for one complete dishwashing cycle. a pump motor that continuously operates for the entire dishwashing operation and at the end of the timer continues operating for 7 /2 seconds during which the machine is not operating. In our present invention the motor and pump are stopped from operating at the end of the washing cycle at which time the drain valve is opened for draining the wash water from the machine. During the subsequent initial adding of fresh heated water into the machine, the drain valve remains open and the fresh water under city water pressure is delivered only to the discharge reservoir where some of the water will pass through the lower spray arm for rinsing the dishes and some will enter the pump for flushing it. Also, some of the fresh water will pass through the upper wash and spray arm for rinsing the dishes and removing any wash water therefrom. The drain valve closes approximately 5 seconds after the fresh water valve is opened. The motor and pump are started when the rinse and fill valve is opened and the valve will remain open until about 2 gallons of fresh heated water is delivered into the machine whereupon a water pressure switch will be opened and will cause the valve to close. A check valve in the fresh water inlet will prevent any reverse flow of water into the city water pipe. During this build up of water pressure the motor will cause the pump to power rinse the dishes and this will continue until the water pressure switch closes the fresh water valve at which time the motor and pump will stop for a very brief period so as to relieve any air lock in the pump. Then the motor and pump are again started and will operate until near the end of the power rinse cycle at which time the detergent valve is opened for a short time and then the entire machine is shut off.

The patentee opens the water valve and the soap valve at the start of the dishwashing operation and this requires time for the soap to mix with all of the water before an effective washing operation takes place. ln our present case the detergent is added at the end of the power rinse cycle to the water that is already in the machine and therefore no time is lost in delivering fresh water into the machine at the start of the next dishwashing operation and furthermore, the detergent will already be mixed in the water.

The patentee also discloses that the waste valve opens twice during the complete dishwashing and sterilizing cycles. Fresh heated water is delivered into the machine at two separate occasions after the initial delivery of fresh water when the machine first starts operating. One of these takes place just before the waste valve closes for the first time and the other takes place during the second time the waste valve opens and shuts off just before the waste valve again closes. In our present invention the drain valve only opens once and this is at the end of the washing cycle. The fresh hot water which is then delivered into the machine for the power rinse cycle, is retained and used as the wash water for the next dishwashing operation.

SUMMARY OF THE INVENTION An object of our invention is to provide a timed cycle for a complete dishwashing operation which will save in the volume of fresh hot water that is required for the complete washing, rinsing and sterilizing of the soiled dishes. About 2 gallons of fresh hot water are required and the dishwashing machine will progress automatically through its timed cycle for washing, rinsing and sterilizing the dishes in about a 2 minute interval.

One of the novel features of the machine is that the 2 gallons of hot water used for the power rinse cycle has a predetermined amount of detergent added to it at the end of the cycle in order that this same water can be used as the wash water for the next load of soiled dishes placed in the dishwashing machine. Another novel feature of our invention is that the motor and pump are stopped from operating for a period of time at the end of the washing cycle and the drain valve is opened for permitting the wash water to drain off. Then just before the drain valve closes, the fresh hot water valve will open and the city water pressure is used for initially directing the fresh hot water out through only the discharge reservoir of the pump and the upper and lower wash and rinse arms for rinsing the dishes, a small quantity of this water being caused to flow through the pump for cleansing it from the wash water. The drain valve then closes and the fresh hot water will continue entering the machine until about 2 gallons enters at which time a water pressure switch will close the water fill valve. The motor and pump will operate during the remaining portion that the fresh hot water is entering the machine and when the fill valve is closed. the motor and pump will be shut off for about one second to relieve any air lock that might be in the pump, after which time the motor and pump will start operating for the power rinse cycle. A predetermined quantity of wetting agent and chlorine are added to the fresh hot water during the time the water is entering the machine.

The timed cycle is ideally designed for use in a commercial dishwasher where the entire sequence of operations are carried out automatically by the machine and all the operator needs to do is to place the soiled dishes in the dishwashing compartment and then depress the starting button. The machine will then automatically wash, rinse and sterilize the dishes in an interval of time of about two minutes. When the machine stops operating, the clean dishes may be removed and another batch of soiled dishes can be placed in the machine. The hot rinse water now is used as the wash water for the new load of dishes because a detergent has been added automatically to the rinse water at the end of the power rinse cycle. So again the operator can start the dishwasher on its next complete cycle by merely depressing the starting button.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of one type of dishwashing machine in which our timed cycle of washing, rinsing and sterilizing the dishes is used.

FIG. 2 is a diagrammatic isometric view showing the entire apparatus and system of our invention in its relation to the same type of dishwashing machine shown in FIG. 1, but in FIG. 2, we are looking at the rear of the dishwasher and it is shown by dot-dash lines.

FIG. 3 is an enlarged side elevation of the dot-dash circled portion shown in FIG. I, and illustrates a visual automatic liquid feeder, three of which are used with the present dishwasher.

FIG. 4 is a top plan view of FIG. 3.

FIG. 5 is a transverse section which is taken along the line 55 of FIG. 4.

FIG. 6 is an enlarged transverse section through a part of the visual automatic liquid feeder and it is taken along the line 6-6 of FIG. 4.

FIG. 7 is a horizontal section taken along the line 77 of FIG. 6 and shows a part of the automatic liquid feeder and it is on the same enlarged scale as FIG. 6.

FIG. 8 is an enlarged transverse section through the waste receiving basket and the drain valve and associate parts and it is taken along the line 88 of FIG. 2.

FIG. 9 illustrates graphically the automatic timing sequences for the complete cycle of the dishwashing, rinsing and sterilizing operation.

FIG. 10 is a diagrammatic view showing the entire apparatus independently of the structure of the dishwashing machine.

DESCRIPTION OF THE PREFERRED EMBODIMENT In carrying out our invention we illustrate our apparatus for washing. rinsing and sterilizing the dishes in a dishwasher shown in FIG. I in which a three-sided door for closing the washing compartment is moved downwardly into the tank for opening the compartment. We are showing this type of dishwashing machine by way of illustrating one example where the apparatus may be used. It can be used on other types of dishwashers. The three-sided door that is movable downwardly into the tank when opening the dishwashing compartment is disclosed in our U.S. Pat. No. 3,582, I 73, issued on June I, 1971, and entitled drinking glass or dishwasher with three-sided door movable downwardly into the tank to open the washing and rinsing compartment.

We will first briefly describe certain parts of the dishwashing machine illustrated in FIG. 1 and then will explain the diagrammatic showing of the operating mechanism as set forth in FIGS. 2 and 10. The dishwasher includes a wash tank indicated at A in both FIGS. I and 2. A vertical back support B extends upwardly from the rear of the wash tank and it carries a hood C at its top. The hood extends over the same area as the top of the wash tank A and is spaced thereabove so as to provide a compartment for receiving a basket, not shown, for

containing dishes that are to be washed. The dish receiving compartment is open on three sides; i.e., at the front and at the left and right hand sides. This permits the basket of dishes, not shown, to be moved into the dishwashing compartment from the front, or from either side thereof. A basket support frame D is mounted in the wash tank A and is spaced inwardly from the adjacent sides of the wash tank so as to provide space for slidably receiving a three-sided door E that is received in the wash tank when the door is in open position.

The three-sided door E has a front wall 1, a left hand wall 2 and a right hand wall 3, see FIG. I. The rear vertical edges of the side walls 2 and 3 are slidably received in vertical door guides 4. The weight of the door is substantially counterbalanced by a weight 5 that is connected to the door by a pair of cables 6 (only one being shown in FIG. 1). The cables have one of their ends connected to the side walls 2 and 3 of the door, and their other ends connected at 7 to the counterbalancing weight 5, the cables being passed over pulleys, not shown, that are disposed under the hood C and are rotatably supported by the vertical hood support B. A handle 8 extends across the front wall I of the door E and brackets 99 secure the ends of the handle to the side walls 2 and 3 of the door. The dishwashing compartment is closed when the operator raises the handle 8 so as to lift the three-sided door E up against the underside of the hood C which acts as a cover for the compartment. The upright B extends across the back of the compartment and makes a watertight seal with the two side walls 2 and 3 of the door when the latter is in closed position. The counterweight 5 will hold the door closed and, if desired, a door lock, not shown, can be used for this purpose.

A lower rotatable wash arm F is mounted just under the dish basket supporting frame D so as to spray wash water upwardly against the dishes for washing them, see FIG. I. The waterjets 10 on the wash arm F will not only direct the water against the dishes for cleaning them but will also direct the water at an angle which will cause the arm to rotate. An upper revolvable wash and rinse arm G is rotatably mounted under the hood C and a pipe II will first deliver wash water to the arm G during the wash cycle and then will deliver fresh rinse water to the same arm during the rinse cycle in a manner hereinafter described. We do not wish to be confined to any particular type of lower wash and rinse arm or upper wash and rinse arm.

It is best now to refer to FIG. 2, and describe some of the apparatus used in washing, rinsing and sterilizing the dishes. The bottom wall 12 of the wash tank A, see also FIG. 8, has an opening I3 for receiving the upper end of a cylindrical sump H, the rim of the sump lying flush with the upper surface of the bottom wall 12. The sump will hold about I gallon of water, although we do not wish to be confined to any particular volume of water that is contained in the sump. A detailed sec tional view of the sump, illustrated in FIG. 8, shows the bottom 14 of the sump provided with a conical-shaped central portion 15 that has a valve seat at 16. Below the valve seat I6 there is a cylindrical housing 17. An outlet drain pipe 18 for the dishwasher communicates with the housing 17.

A drain valve J normally rests against the valve seat 16 and prevents any water in the sump H from escaping through the drain pipe 18, see FIG. 8. The drain valve J is hydraulically operated and a piston 19 is movably mounted in the lower end of the cylindrical housing 17 and it has a piston rod 20 that extends upwardly and is connected to the drain valve J. A combined partition and piston rod guide 21 extends across the cylindrical housing 17 at a point where the drain pipe 18 communicates with the housing and prevents any dishwater that drains from the sump H when the valve J is opened, from entering the lower portion of the housing 17 in which the piston 19 moves. A coil spring 22 has its upper end bearing against the underside of the partition 21 and has its lower end bearing against the piston 19 for urging it downwardly and keeping the drain valve normally closed against the valve seat 16. We will describe hereinafter how the hydraulic piston 19 will be raised at a certain time interval for opening the drain valve J and permitting the water in the sump H to flow out through the drain pipe 18.

The sump H has a strainer basket K removably mounted therein, as shown in FIG. 8. The basket has a cylindrical wall 23 provided with small openings 24, preferably l/32 of an inch in diameter. The basket K has a bottom wall 25 that rests on the bottom wall 14 of the sump H. The portion of the bottom wall 25 that overlies the conical central cavity portion of the sump is provided with larger openings 26, preferably about 4 inch in diameter, so as to permit certain sized food particles to pass from the basket K into the conical cavity portion 15 of the sump and thence into the drain pipe 18 when the drain valve is opened. The strainer basket K has a handle 27 that extends inwardly from the rim of the basket for permitting the removal of the basket for cleaning purposes. The drain valve J has an upstanding and centrally disposed overflow pipe L that extends through a center opening 28 in the bottom wall 25 of the strainer basket K. The piston rod receives the lower end of the overflow pipe L and the piston rod has a horizontal passage 29 that communicates with the lower end of the overflow pipe so that any excess water in the wash tank A will enter the overflow pipe L and pass through the passage 29 and out through the drain pipe 18. The overflow pipe L and the piston J move as a unit when the hydraulic piston 19 is moved upwardly in a manner hereinafter described. The cylindrical housing 17 that extends below the conical central portion 15 of the sump H is provided with a radially extending tubular portion 30 that is aligned with the drain pipe 18, see FIG. 8. A screw plug 31 normally closes the outer end of the tubular portion 30.

We have described the rotatable lower wash and rinse arm F and the upper rotatable wash and rinse arm G, see FIG. 1, and now we will describe how fresh hot water, under city water pressure, is conveyed to both arms F and G. In the schematic showing of FIGS. 2 and 10, a fresh water supply pipe is indicated at 32. A water strainer 33 is connected to the inlet pipe 32. A rinse and fill solenoid valve 34 is shown mounted in the water line 32 and we will describe hereinafter at what time this valve is automatically opened for permitting fresh hot water to enter the dishwasher. A water flow rator 35, see FIG. 2, may also be mounted in the fresh water inlet pipe 32 and the pipe extends upwardly to a vacuum breaker, shown at 36. From the vacuum breaker 36, a water pipe 37 leads to a check valve 38 that will only permit the water to flow in the direction of the arrow 39 associated with this check valve. A

water pipe 40 extends from the check valve 38 to a T, indicated at 41 and two pipes lead from the T" 41. The pipe 11, see also FIG. 1, for the upper wash and rinse arm G, is connected to the T 41, as shown in FIG. 2 and also FIG. 10. The other pipe 42 extends downwardly from the T 41 and communicates with a water discharge reservoir 43. A water pipe 44 places the discharge reservoir 45 in communication with a water pump M that is operated by a motor N. When describing the operation of the dishwasher we will show that the rinse and fill valve 34 will be opened after the wash cycle is completed and after the drain valve J has been opened for a predetermined time period during which time the motor M and the pump N are stopped. The opening of the rinse and fill valve 34 is accomplished at the time the motor and pump are again started and for the initial period of about 5 seconds. the fresh hot water will flow through the pipe 11 and out through the upper spray arm G and will also flow through the pipe 42, discharge reservoir 43 and pipe 44 for flushing the pump M. The water will then flow through a pipe 48 into the sump H and past the still open drain valve J and out through the drain pipe 18.

We have illustrated schematically in FIG. 9 a timing sequence of about two minutes duration covering the complete cycle of washing. rinsing and sterilizing the dishes and this 2 minute time interval is divided into l20 seconds. We do not wish to be confined to this precise 2 minutes complete cycle period because in certain instances the total time period may have to be altered. However, one of the novel points in the timed 2 minute cycle is that the motor N that operates the water pump M, see also FIGS. 2 and 8, is stopped at the 55 second interval for a period of [0 seconds which is at the end of the dishwashing cycle to permit the wash water to drain and is also stopped momentarily at the 89 second interval which is at the end of the fresh hot water filling operation to permit the freeing of any air lock in the water pump. We have first described the hot water filling operation of the machine even though as shown in the graphic illustration of FIG. 9, the entrance of fresh hot water takes place after the machine has been operating on a wash cycle for 55 seconds, (note the graph line 49) and after the motor and pump have been stopped for l0 seconds. The left hand portion of the graph line 49 lines up with the word CLOSE" and then at the 65 second interval, the graph line 49 extends upwardly at 49a, and then extends along a horizontal line 49b that lines up with the word "OPEN". The hot water filling operation has first been described because when the machine is first started to operating, it is necessary to supply the machine with about 2 gallons of hot water. The sump H will hold about l gallon and the other gallon is received in the tank A.

Before describing any more of the different sequences of operation, it is best to set forth how the detergent, wetting agent and chlorine are fed into the dishwashing machine. In FIGS. 1, 2 and I0, we show three containers 50, S1 and 52. The container 50 has a detergent therein while the container 51 has a wetting agent and the container 52 has chlorine therein. Each of the three containers is connected to its associate visual automatic liquid feeder by conduits. The detergent container 50 has a conduit 53 connecting it to its associate visual automatic liquid feeder P. In like manner the wetting atent container 51 has a conduit 54 connecting it to its associate liquid feeder Q, and the chlorine container 52 has a conduit 55 connecting it to its associate liquid chlorine feeder R. In FIGS. 2 and 10, the conduits 53, 54 and 55 are illustrated by arrowed lines.

Since the visual automatic liquid feeders P, Q and R are all identical in construction, a detailed description of the detergent feeder P will suffice for all of them. In FIGS. 3 to 7 inclusive, we illustrate the feeder P which comprises a cylindrical transparent body 56, a base 57 and a cover 58. The conduit 53 that leads from the detergent container 50 communicates with the interior of the feeder P through the base 57, see FIGS. 3 and 5. A dip tube 59 extends through an opening 60 in the cover 58 and its lower end is spaced a slight distance above the inner surface of the base 57, see FIG. 5. The dip tube 59 has a central bore 61 that extends upwardly from the bottom of the tube to an enlarged compartment 62, see FIG. 6. A valve adjustment plug 63 is screwed down into the upper threaded portion in the compartment 62 and the plug carries a depending metering rod 64 that extends into the central bore 61 and has a diameter slightly less than that of the bore. A pair of rings 65 and 66 encircle the metering rod 64 and prevent the passage of any detergent thereby.

Both FIGS. 6 and 7 show the metering rod 64 and associate parts on a greatly enlarged scale from the full size view of the liquid feeder P, shown in FIGS. 3, 4 and 5. At the lower end of the metering rod 64, we provide a V-shaped groove 67 adjacent to the periphery of the rod. The adjustment plug 63 has a kerf in its top whereby a screwdriver, not shown, can be used for rotating the plug and raising or lowering the metering rod 64 with respect to the lower 0 ring 66 so that the desired amount of the V-shaped groove 67 can extend above the O ring 66, see FIG. 6, so that a controlled fluid passage is provided in the bore 61 in the dip tube 59 from a position below the bottom of the metering rod 64 to a position above the O ring 66. A metered quantity of detergent can flow into the portion of the bore 61 above the O ring 66 and enter a transverse passage 68 in the plug 59 when a vacuum is applied in the passage, see FIG. 6. A coil spring 69 in the compartment 62 frictionally bears against the bottom of the plug 63 for holding the latter against accidental rotation. The passage 68 extends through the plug 59 and the cover 58.

FIGS. 3, 4 and show a conduit 70 communicating with the detergent outlet passage 58 in the visual automatic liquid feeder P and FIGS. 2 and schematically show the conduit 70 leading to a venturi control unit, shown diagrammatically at S. A branch water line 71, in FIGS. 2 and 10, leads from the hot water supply line 32 to the venturi S and a conduit 72 leads from the venturi to the sump H. The branch water line 71 has a solenoid valve 73 in it, and when this valve is opened by a timed circuit, the fresh hot water will flow through the branch pipe 71 and enter the venturi S for creating an entraining action on the end of the detergent carrying line 71. This entraining action within the venturi will draw off the proper amount of liquid detergent from the line 70 and will mix it with the water and force it through the pipe 72 into the sump H, where it will mix with the water therein. A control valve, not shown, for the venturi S, regulates the amount of detergent delivered to the sump H.

The graph line 74 in FIG. 9 shows that the detergent controlling solenoid valve 73 of FIGS. 2 and 10, is opened after the dishwasher has been operating for about I I5 seconds and the valve remains open for about 3 seconds and then closes. Again the graph line 74 moves vertically between the CLOSE and OPEN positions to indicate when the detergent valve is operated. The detergent valve 73 is opened for about 3 sec- 5 onds just before the entire 2 minute cycle is completed. When the detergent valve 73, in FIG. 2, is opened, it will create a suction in the detergent line 70 due to the entraining action on the line by the venturi S. Therefore, the suction in the line 70 will draw detergent fluid from the interior of the cylindrical body 56 of the visual automatic vacuum controlled detergent liquid feeder P, see FIG. 5. As the liquid is withdrawn from the body 56, a vacuum will be created above the top of the liquid. As soon as this occurs, a branch radial bore 75 in the dip stick 59 places the upper interior portion of the liquid feeder P in communication with the central bore 61. The vacuum in the radial bore 75 and in the upper portion of the central bore 61, will be strong enough to cause additional liquid detergent to be drawn from the detergent container 50 and to flow through the line 53 and enter the bottom of the feeder P, and thus replenish the supply of detergent in the feeder. This feeding will continue until the liquid level reaches the passage 75 and closes it. The transparancy of the cylindrical body 56 will permit the operator to ascertain at any time whether the detergent liquid in the feeder is getting low. When this occurs, a new container 50 of liquid detergent can be connected to the line 53 and take the place of the empty one. The visual automatic liquid feeders P, Q and R are preferably mounted on top of the dishwasher where they may be readily inspected by the operator, as shown in FIG. 1, while the containers 50, 51 and 52 for containing the supply of liquid detergent, wetting agent and liquid chlorine, respectively, may rest on the floor.

We have described in detail how the visual automatic liquid feeder P operates and, since the feedeers Q and R are of identical construction, a detailed description of them will not be necessary. We also have described how the automatic time controlled cycles have opened the rinse and fill valve 34 after the dishwasher initially has operated for about 65 seconds and how that 2 gallons of hot fresh water is fed into the machine through the upper and lower wash and rinse arm G for a time period of about 24 seconds (note the graph indicating line 49 in FIG. 9, with its horizontal portion 49b extending from the 65 second position to the 89 second position). Furthermore, we have also set forth how the detergent valve 73 is opened after the machine has operated for about I I5 seconds, see graph line 74 in FIG. 9, and then remains open for about 3 seconds for feeding a liquid detergent into the water in the sump H for mixing with the water. About two seconds after the detergent valve 73 closes, the entire machine stops operating because the complete cycle of l seconds or 2 minutes has been finished. A timing motor, not shown, and a plurality of cams, not shown, are operated by the motor for closing switches, not shown, in proper sequence that will cause the machine to operate automatically for a period of about 2 minutes, each time the starting button 76, see FIG. 1, is depressed. The showing of the various graph lines in FIG. 9, is thought to be sufficient to illustrate how the machine operates without showing the cam mechanism and the electric switches.

We have described thusfar the initial operation of the dishwasher in getting it ready for receiving its first load of soiled dishes. Up to this point, no dishes have been placed in the machine. The dishwasher is now ready to receive its first load of soiled dishes. It might be well to state, however, that during the initial run-through of the machine, the drain valve J will open after about 55 seconds have elapsed from the closing of the starting button 76 even though there is no water as yet in the machine, (note the graph line 77 in FIG. 9, which represents the time the drain valve opens and closes). Hot fresh water does enter the machine after about 65 seconds have expired and seconds later; i.e., at the 70 second position on the graph, the drain valve closes while the rinse and fill valve 34 still remains open. Immediately upon the closing of the drain valve 1, the wetting agent and liquid chlorine are added to the water.

Referring again to the schematic drawing of FIG. 2, it will be seen that a branch conduit 78 leads from the fresh water inlet pipe 32 to a second venturi U. We have already described how the wetting agent is fed from its container 51 to the associate visual automatic liquid feeder Q by means of the venturi 54. Another conduit 79 leads from the feeder Q and conveys the wetting agent to the venturi U. Note also that the liquid chlorine is fed from its container 52 through the conduit 55 to the visual automatic liquid feeder R and from this unit the liquid chlorine is fed through a conduit 80 to a chlorine control valve 81, and thence through a conduit 82 that connects with the portion of the conduit 79 for conveying the liquid chlorine to the venturi U. Therefore, both the wetting agent from the conduit 79 and the liquid chlorine from the conduit 82, enter the venturi U, when the rinse and fill valve 34 is opened and some of the fresh hot water under the city water pressure will enter the conduit 78 and will flow into the venturi U for entraining both the wetting agent and the liquid chlorine for delivering them into the sump H by means of the short conduit 83.

OPERATION From the foregoing description of the various parts of the device, we will now set forth the various sequences for the entire washing, rinsing and sterilizing cycle for the dishes. When the starting button 76 is depressed, the dishwasher has already received about two gallons of hot water and the detergent has been mixed into the water. The dishes have been placed in the machine. The motor N, see control graph line 84 in FIG. 9, will immediately start and operate the water pump M for 55 seconds. FIG. 10 shows that the hot detergent water will be forced into the pipe 44 and from there the water will be forced into the discharge reservoir 43 and then upwardly through the pipe 47 to the lower wash arm F. Some of the water will be forced from the discharge reservoir through the pipe 42, *T" 41, pipe 11, and out through the upper wash and spray arm G. The check valve 38 prevents any water flowing in a reverse direction through the pipe 37. The graph line 84 in FIG. 9 shows that the motor N and pump M after operating for about 55 seconds for thoroughly washing the dishes. will stop.

At the same 55 second interval the drain valve J will be opened and this is indicated by the graph line 77 in FIG. 9. The means for accomplishing this is shown schematically in FIG. 2 and also is shown in FIG. 8. A conduit 85 communicates with the fresh water conduit 32 in FIG. 2 and with the cylindrical housing 17 at a point below the piston 199 that slides in the housing as shown in FIG. 8. A solenoid controlled valve 86, see FIG. 10, is mounted in the conduit 85 and the solenoid is energized at the proper time for opening the valve 86 after the dishwashing machine has been operating for 55 seconds. The city water pressure will cause the incoming water to lift the piston 19 in FIG. 8 against the compression spring 22 for opening the drain valve .1. During the washing operation the hot detergent wash water has been sprayed against the dishes from both the upper and lower wash arms G and F, respectively. The wash water has flowed into the tank A and thence into the sump H and food particles carried by the water will drop into the strainer basket K. The pump M will draw the water out of the sump I-I, through the pipe 48 and will recycle the hot detergent water through the pipe 44, discharge reservoir 43 and pipes 47, 42 and 11 to the wash arms F and G for thefurther washing of the dishes. The wetting agent from the container 51 has also been mixed with the wash water during the initial operation of the machine and, therefore, when the motor and pump stop at the end of 55 seconds of operation and the drain valve .1 opens, the wash water will flow past the valve, see FIG. 8, and out through the drain 18. Any small food particles in the basket K will pass out through the openings 26 in the bottom of the basket and will flow out the drain 18.

FIG. 9 shows from graph line 77 that the drain valve .l remains open for 15 seconds (i.e. from the 55 second to the second position on the overall time cycle). The motor N and the pump M will stop operating for 10 seconds from the 55 second position to the 65 second position on the full cycle graph of FIG. 9. The drain valve J is still open when the motor and pump start operating again at the 65 second position. The rinse and fill valve 34 opens at the 65 second position and the initial fresh hot water that flows through the pipes 32, 37 and 11 to the upper wash and rinse arm G, and through the pipe 42, reservoir 43, and pipe 47, see FIG. 10, to the lower wash and spray arm F for rinsing the dishes for 5 seconds (i.e. from the 65 second position to the 70 second position in FIG. 9). The water will also flush the tank A before the drain valve closes at the 70 second position. During this 5 second interval some of the fresh water will flow from the discharge reservoir 43, through the pipe 44 and will flush the pump M of wash water. The wetting agent from the container 51 and the liquid chlorine from the container 52 are fed into the sump H while the rinse and fill valve 34 remain open.

The fresh water continues entering the dishwashing machine until it fills with about 2 gallons of hot fresh water. This is shown on the graphic illustration of FIG. 9, by the graph line portion 49b from the 65 second po sition to about the 89 second position. The motor N and the pump M are operating while the rinse and fill valve 34 is open and, therefore, the dishes will be effectively rinsed of wash water. As soon as the machine receives about 2 gallons of fresh hot water. the pressure switch V, see FIG. 10, shuts off the rinse valve 34, see also FIG. 2. A conduit 87 leads from the pressure switch V to the discharge reservoir 43 and when the water pressure in this reservoir reaches a point where about 2 gallons of fresh water are received in the dishwasher, the pressure switch V will open and will cut off the current to the solenoid controlled inlet valve 34, permitting it to close.

When the hot fresh rinse water ceases to flow into the machine, a time period of about 89 seconds has elapsed. and the motor N and pump M will stop operating for about I second (note the dip in the graph line 84 at the 89 second and 90 second interval in the graphic illustration of FIG. 9). The motor and pump will shut off for this short time interval in order to relieve any air lock in the pump. The motor then starts again after this one second stop and operates the pump for the power rinse cycle which lasts for about 25 seconds (from the 90 second time interval to the 115 second time interval). The wetting agent and the liquid chlorine have both been added to the fresh rinse water and the dishes will therefore be sterilized during the power rinse cycle.

At the end of the 115 second time interval, the motor N again shuts off and this stops the pump and brings the power rinse cycle to an end. When the motor shuts off, the detergent valve 73 opens in the manner already described and will remain open from the 115 second time interval to the U8 second time interval, see the graph line 74 in FIG. 9. The timer, not slo wn, controls this 3 second interval when detergent is fed into the dishwasher. The timer shuts down the entire machine at the end of 120 seconds. The hot rinse water with the added detergent thoroughly mixed in it, is now ready to be used as the wash water for the next load of soiled dishes. All the operator needs to do is to remove the clean and sterilized dishes from the machine and place a load of soiled dishes in the machine and again depress the starting button 76, whereupon the two minute automatic wash rinse and sterilizing cycles will be again repeated.

It will be noted from FlC-S. l and 2, that a water pressure gage W is mounted on the machine and a conduit 88 leads from this gage to the conduit 87 that is connected to the discharge reservoir 43. Also in the same two FIGS. l and 2, and FIG. 10, we show a thermostat X and a line 89 leads from it to the discharge reservoir 43. This thermometer will give the temperature of the wash and rinse waters in the machine and the pressure gage W will indicate the water pressure. We make use of a timing mechanism. not shown, that rotates cams. not shown, in proper sequence for opening and closing electric switches, not shown. that control the solenoid rinse and fill valve 34, the solenoid controlled valve 86 for the drain valve 1. and the pump motor N. in the manner shown in the graphic illustration of FIG. 9.

We claim:

I. A dishwashing machine comprising:

a. a tank for holding hot water;

b. a dishwashing compartment adapted to receive dishes to be washed;

c. an upper wash and rinse arm mounted in said compartment and positioned above any dishes receivable in the compartment;

d. a lower wash and rinse arm mounted in said compartment and positioned below any dishes receivable in the compartment;

e. a motor driven pump having a first water conveying means communicating with the water in said tank and delivering this water to said upper wash and rinse arm, and having a second water conveying means communicating with said tank for drawing water therefrom and for forcing it through said first and second water conveying means for causing the water to be sprayed through both of said upper and lower wash and rinse arms and all of it returned to said tank;

f. a source of hot fresh water under pressure with a valve-controlled third water conveying means com municating with a portion of said first and second water conveying means for delivering the hot water to both of said wash and rinse arms when said valve is opened;

g. a first check valve in said third valve-controlled water conveying means for preventing any reverse water flow therein;

h. a timing cycle for opening said third valvecontrolled water conveying means for permitting fresh hot water to enter said third water conveying means for causing this water to issue through said upper and lower wash and rinse arms and then flow into said tank; and

i. a switch for closing the valve when a predetermined volume of fresh water has entered said tank;

j. said timing cycle then starting the motor driven pump for removing water from said tank and forcing it into said first and second water conveying means for forcing the water out through both wash and rinse spray arms and into said tank for recirculating the water, said first check valve preventing any of this water from reversing its flow through the third valve-controlled fresh water conveying means.

2. The combination as set forth in claim 1: and in which a. said timing cycle causing the motor driven pump to operate for a specified time period before shutting off; and

b. a detergent valve and means controlled by the timing cycle for opening said detergent valve for a short period of time just prior to the timing cycle shutting off said motor driven pump.

3. A dishwashing machine comprising:

a. a tank for holding water;

b. a dishwashing and rinsing compartment for dishes disposed above said tank in a position where all washing or rinsing water received in said compartment will drain into said tank at all times;

c. an upper and lower wash and rinse arm rotatably mounted in said compartment;

d. a motor driven pump having a first water conveying means for receiving water from said tank and having a second water conveying means for conveying the water to said upper and lower wash and rinse arms;

e. a source of hot fresh water supply;

f. a first valve and a third water conveying means connecting with portions of said first and second water conveying means for placing said fresh water supply in communication with said upper and lower wash and rinse arms for rinsing the dishes in said compartment, there being a check valve in the source of fresh water supply for preventing any reverse flow of water in the fresh water supply;

g. electrical time controlled means for opening said first valve after a predetermined time interval, said time controlled means holding said first valve open for delivering a predetermined volume of hot fresh water through said upper and lower wash and spray arms;

h. means is provided and is actuated by the flow of fresh hot water under pressure when said first valve is opened for delivering a wetting agent and a sterilizing agent to the incoming water, and including a container for the wetting agent and another container for the sterilizing agent; and

i. a separate visual automatic vacuum controlled feeder connected to each of said containers for automatically withdrawing the contents from said containers as needed and delivering the wetting and sterilizing agents to the incoming fresh water, the visual portion of each feeder showing the operator when to supply a new filled container for an empty one, said incoming fresh water actuating vacuum means for creating a vacuum in said visual automatic feeders for drawing the wetting and sterilizing agents from said containers and delvering them to said automatic feeders.

4. A dishwashing machine comprising:

a. a tank for holding water;

b. a dishwashing and rinsing compartment for dishes disposed above said tank in a position where all washing or rinsing water received in said compartment will drain into said tank at all times;

c. an upper and lower wash and rinse arm rotatably mounted in said compartment;

d. a motor driven pump having a first water conveying means for receiving water from said tank and having a second water conveying means for conveying the water to said upper and lower wash and rinse arms;

e. a source of hot fresh water supply;

f. a first valve and a third water conveying means connecting with portions of said first and second water conveying means for placing said fresh water supply in communication with said upper and lower wash and rinse arms for rinsing the dishes in said compartment, there being a check valve in the source of fresh water supply for preventing any reverse flow of water in the fresh water supply;

g. an electrical time controlled means will shut off the pump motor and stop the operation of the pump for a brief period at the end of the fresh water delivering operation so that any air lock in said pump will be freed;

h. the electrical time controlled means will again start the motor driven pump when the air lock has been freed and the pump will recirculate the rinse water through both of the upper and lower wash arms for power rinsing the dishes in said compartment for a predetermined time period; and

. at the end of this rinsing period the electrical time controlled means will stop the motor pump and will open a detergent valve for feeding a predetermined amount of detergent into the rinse water preparing it to constitute the wash water for the next sequence of cycles, whereupon the electrical time controlled means will stop functioning.

5. The combination as set forth in claim 4: and

a. a starting switch for again starting the time controlled means and causing the motor pump to start and recirculate the wash water with its detergent through both the upper and lower wash arms for washing the dishes for a predetermined time period;

b. said time controlled means stopping the motor driven pump at the end of the dishwashing period and opening a drain valve for permitting the wash water to pass out through a drain for a predetermined time period c. said time controlled means opening the rinse and fill valve for admitting fresh hot water while the drain valve remains open for a short time for causing the fresh water to flush said tank; and

d. said time controlled means closing said drain valve and permitting a predetermined volume of fresh water to be delivered through said upper and lower wash and spray arms.

Patent Citations
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4051858 *Dec 27, 1976Oct 4, 1977Mele Anthony PSolvent sink and dispenser
US4209343 *Sep 1, 1978Jun 24, 1980Hobart CorporationMethod for air transport of sanitizing liquid to a warewasher
US4285352 *Sep 12, 1979Aug 25, 1981Hobart CorporationContinuous duty chemically sanitizing batch rinse system
US4439242 *Oct 18, 1982Mar 27, 1984Hobart CorporationLow hot water volume warewasher
US4781206 *Apr 11, 1986Nov 1, 1988The Stero CompanyFor undercounter installation
US4801396 *Jul 20, 1987Jan 31, 1989Henkel Kommanditgesellschaft Auf AktienDishwasher detergent paste
US4810306 *Feb 26, 1986Mar 7, 1989The Stero CompanyLow energy, low water consumption warewasher and method
US4836229 *Dec 22, 1988Jun 6, 1989Ecolab Inc.Dishwashing apparatus including a flip-top solid detergent dispenser
US4848382 *Oct 22, 1987Jul 18, 1989Whirlpool CorporationTub bottom soil separator for dishwasher
US4872466 *Dec 12, 1988Oct 10, 1989Hobart CorporationLow energy, low water consumption warewasher
US4938240 *Apr 21, 1989Jul 3, 1990Ecolab Inc.Dishwashing apparatus including a flip-flop solid detergent dispenser
US5448115 *Aug 12, 1992Sep 5, 1995Nova ControlsWarewashing control system and method of operation
US5481918 *Jun 13, 1994Jan 9, 1996Olympus Optical Co., Ltd.Acoustic lens system
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US5775592 *May 16, 1996Jul 7, 1998Suttner America CompanyUpstream inlet injector
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US6615850Sep 11, 2000Sep 9, 2003General Electric CompanyDishwasher sanitation cycle
US7146992 *Jul 2, 2002Dec 12, 2006Maytag CorporationDishwasher pump and filtration system
US8252121 *Nov 28, 2007Aug 28, 2012Premark Feg L.L.C.Drain system for a warewasher
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EP0001356A1 *Sep 20, 1978Apr 4, 1979Hobart Corporation (a corporation of the State of OHIO)Method and apparatus for chemically sanitizing foodware items
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Classifications
U.S. Classification134/58.00D, 134/95.1, 134/113, 134/99.2
International ClassificationA47L15/46, A47L15/44
Cooperative ClassificationA47L15/0055, A47L15/4236, A47L15/0081, A47L15/0036
European ClassificationA47L15/00E6, A47L15/00C1F, A47L15/42F, A47L15/00C10
Legal Events
DateCodeEventDescription
Aug 4, 1988ASAssignment
Owner name: HSW HOLDINGS, INC., 3200 LAKEVILLE HIGHWAY PETALUM
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:STERO DISHWASHING MACHINE MFG. CO., A CA CORP.;REEL/FRAME:004961/0593
Effective date: 19850409
Owner name: STERO COMPANY, THE,
Free format text: CHANGE OF NAME;ASSIGNOR:HSW HOLDINGS, INC.;REEL/FRAME:004941/0034
Effective date: 19850410
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:STERO DISHWASHING MACHINE MFG. CO., A CA CORP.;REEL/FRAME:004961/0593
Owner name: HSW HOLDINGS, INC., A DE CORP., CALIFORNIA
Apr 24, 1987ASAssignment
Owner name: STERO DISHWASHING MACHINE MFG. CO., 3200 LAKEVILLE
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:NOREN, TORE;FEDERIGHI, GEORGE;REEL/FRAME:004748/0384
Effective date: 19850409
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:NOREN, TORE;FEDERIGHI, GEORGE;REEL/FRAME:004748/0384
Owner name: STERO DISHWASHING MACHINE MFG. CO., CALIFORNIA
Apr 24, 1987AS02Assignment of assignor's interest
Owner name: FEDERIGHI, GEORGE
Effective date: 19850409
Owner name: NOREN, TORE
Owner name: STERO DISHWASHING MACHINE MFG. CO., 3200 LAKEVILLE