US3370597A - Dishwashing machine with liquid sanitizer dispenser - Google Patents

Description

G. B. FOX

Feb. 27, 1968 DISHWASHING MACHINE WITH LIQUID SANITIZER DISPENSER Filed Feb. 20, 1964 INVENTOR. GERALD B. FOX

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FIG-'2 United States Patent 3,370,597 DISHWASHING MACHINE WITH LIQUID SANITIZER DISPENSER Gerald B. Fox, Troy, Ohio, assignor to The Hobart Manufacturing Company, Troy, Ohio, a corporation of Ohio Filed Feb. 20, 1964, Ser. No. 346,261 1 Claim. (Cl. 134-58) ABSTRACT OF THE DISCLOSURE Background of the invention This invention relates to a novel apparatus for cleansing dishes, kitchen utensils, and the like.

This invention is particularly useful in connection with dishwashing machines of relatively small capacity, as used in small restaurants, small kitchens such as in rest homes or diet kitchens, or as used in beverage stands, bars, soda fountains and the like. These machines operate on a relativel" short time cycle, and the final fresh water rinse of the soiled dishes or other articles must be sufiicient to kill bacteria which might be present on the articles. In many instances this is accomplished by a fresh zater rinse with water at a temperature of 180 F. or

higher, and most local and state health and sanitation codes have specific provisions in this regard.

There are a number of circumstances, however, where due to the limited capacity of the available hot water heating system, such a higher temperature fresh water source is not readily available, and in such instances it has heretofore been the usual practice to add a so-called booster heater, having either an electrical heating element or a gas burner heater, to the dishwashing machine. However this is inherently a rather expensive accessory to the dishwashing machine, and other provisions for assuring a bactericide final rinse in these machines are desirable.

Accordingly, the principal object of this invention is to provide a novel apparatus for cleansing soiled dishes and the like wherein a bactericide final rinse of the articles being cleansed is assured without resort to auxiliary heating equipment.

Another object of the invention is to provide such an apparatus to add a predetermined amount of sanitizing agent at least to the final rinse water used in the cycle of operations of the dishwashing machines to obtain the desired bactericide, and wherein this apparatus can be provided as an inexpensive and conveniently attached accessory to a dishwashing machine of conventional construction.

A further object of the invention is to provide a novel apparatus for cleansing soiled dishes and the like in a dishwashing machine, wherein a readily attainable disinfectant material is automatically added in proper amount to the cleansing liquid used in a dishwashing machine, thereby to utilize such cleansing liquid as a bactericide without the need of heating this liquid to elevated temperatures.

3,370,597 Patented Feb. 27, 1958 apparatus wherein the disinfectant liquid is a commercially obtainable disinfectant having as an active ingredient sufiicient hypochlorite to assure that the cleansing liquid contains an adequate number of parts per million of chlorine to function efiectively as a bactericide.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claim.

In the drawings:

FIG. 1 is a perspective view of a dishwashing machine, incorporating apparatus according to the present invention;

FIG. 2 is a side view of the machine shown in FIG. 1, with parts broken away to show the general arrangement of the spray system;

FIG. 3 is a somewhat diagrammatic view showing the essential elements of an attachment in accordance with the invention for supplying the sanitizer to the machine;

FIG. 4 is a detailed view showing the construction of a suitable metering valve used in the apparatus shown in FIG. 3; and

FIG. 5 is a schematic Wiring diagram.

Referring to the drawings, which illustrate a preferred embodiment of the invention, FIG. 1 shows a typical form of dishwashing machine to which the present invention applies. This machine includes a cabinet 10 having therein a cleansing chamber 12, and at the front of this chamber there is a door 14 hinged at its lower edge to provide access to the chamber 12. This door also provides a sup port, in its open position, for the racks 15 which hold the 1 articles to be cleansed in the chamber 12.

Another object of the invention is to provide such an As shown in FIG. 2, the chamber 12 has at its bottom a sump 17 and below this sump is a motor-pump unit 18 which is connected to supply liquid from the sump to the rotary spray apparatus or wash arm 20. The construction of the motor-pump unit and of the Wash arm may be of the type shown in US. Patent No. 2,862,510, and this recirculating system may include a strainer construction (not shown here) such as disclosed in said patent.

The sanitizer material preferably is in the form of a liquid, as explained hereafter, and a supply is provided in a reservoir jar 25 which is carried in a suitable bracket 26 fastened to the housing 10. Preferably, the bracket includes a vertically extending slot 27 to provide for inspection of the level of liquid in the reservoir 25. A supply tube 28 extends from the bottom of the jar through a suitable hole in the wall of cabinet 14), and along the wall 12a of the chamber 12 to an automatically operable metering device 30. Details of this device are shown in FIG. 4.

The body 31 of the device is carried on a suitable bracket 32 fastened to the wall 12a, and in the central portion of the body 31 there is a metering chamber 35 defined by the space between the bafiies 36 and 37. The aperture 39 through the bafile' 36 leads from the chamber 35 to a discharge chamber 40 which in turn is connected to the outlet 42 of the device 30, and this outlet is mounted to communicate with the interior of the chamber 12. A valve body 44 is carried on a flexible diaphragm 45, preferably as an integral part thereof, and the periphery of this diaphragm is clamped in sealed relation to the body 31 by means of the mounting plate 46. An operating rod 50 extends through the center of the valve member 44, and at the back of this member there is an enlarged flange-like part 51 which presses against the valve member 44, and it in turn is engaged with a spring 52 tending to hold the valve member 44 in its seated position as shown. The rod 54 extends through chamber 35 and through an opening 53 in the bafile 37, into the inlet chamber 55 of the metering device. On this portion of the rod 50 there is a secondary valve in the form of a flexible valve head 58, which is normally open as shown to permit communication between the tube 28 and chamber 35.

The opposite end of rod' 50 is secured to the armature piece 60 of the operating solenoid, and this armature extends into the support tube 61, around which is mounted the solenoid winding 62. The tube 61 also provides a support for the spring abutment cup 64. Preferably, a cover 65 encloses the entire solenoid assembly and is fitted against the plate 46. The terminals 66 extend from the end of cup 65 for connecting the solenoid winding into an actuating circuit.

The operation of the device is apparent from the drawing. Energizing the solenoid draws its armature, and thus rod 50, to the left (as in FIG. 4) opening valve 44 and closing valve 58. This permits the contents of the metering chamber 35 to drain through the discharge chamber 40 and the outlet 42 into the cleansing chamber 12 of the machine. When the solenoid is deenergized the parts resume the position shown and chamber 35 is refilled by gravity flow from the reservoir 25.

Referring to FIG. 5, the operation of the machine is as follows. The manually operable push button control switch 70 is arranged as a master control of electrical power to the machine. This switch preferably is located on the machine, for example as shown in FIG. 1. It may i be of the SPDT type, which remains in either of two positions, thus closing a circuit from the supply line L2 to either of the contacts 70a'or 70b. Either of the lines 7 leading from these contacts is thus capable of completing a power circuit to the timer 75, which incorporates five cam operated switches 75a, 75b, 75c, 75d and 75e. The cams operating these timer switches are of conventional construction, and thus not shown, but their general arrangement is indicated by the timer motor 76 and the dotted line 77 representing the cam control of the timer switches. Timer switch 75a has two control contacts 7511-1 and 75a-2, which are connected to the push button switch contacts 70a and 70b. It will be understood that when the timer stops it is on an appropriate contact to open the circuit from the switch 70.

To initiate operation of a cycle of the machine, the switch 70 is moved to the contact opposite from that on which it rests when the machine stops, and a power circuit is completed through switches 79 and 75a to the safety micro-switch78. Switch 78 is mounted in the machine in a conventional manner, to be closed whenever the door 14 is closed, and to open this circuit when the door is opened. Assuming that the door is closed, the

power circuit then is completed through the timer motor 76 to supply line L1.

The timer switch 75b is connected through its contact 75b-1 to control power to the pump motor PM, which is the motor portion of the pump-motor unit 18. Power will be supplied to this pump motor as long as the aforementioned main power circuit is completed and timer switch 75b is closed.

In machines of this type, there are generally two separate fill valves, shown in FIG. as FV-l and FV-2. Valve FV-1 is connected froman ordinary hot water supply (for example 140 F.) to the chamber of the machine, and this valve will be opened to fill themachine with this lower temperature water during the washing operation. The timer switch 756 controls the supply of power to the solenoid of valve FV-l through its contact 75c1. A separate solenoid operated valve FV-2 is arranged for connection to a higher temperature water supply, for example 180 F. When thissupply is available, such high temperature water is admitted to the chamher through valve FV-2 during the rinsing cycle. When the machine is equipped with the sanitizer device in accordance with the invention, the inlets to the valves FV-l and FV"2 will be connected to the same lower temperat'ure water suppl and the high temperature water supply is not needed. The timer switch 75d controls the electrical power supplied through its contact 75d1'to the v 4 solenoid of valve FV-Z and to the solenoid '62 of the sanitizer metering device 30. The timer switch e is connected to supply power through its contact 752-1 to the solenoid of the drain valve DV, which is connected to open and close the drain line from the sump 17.

The operation of the machine is such that when a cycle isinitiated by operating switch 70, assuming that the door is closed, the fill valve FV is energized for approximately 30 seconds by closing timer switch 750, timer switch 75a is closed to energize drain valve DV and close it, and

switch 75d is closed to energize the pump-motor. As the;

sump fills with water the pump will operate and begin to circulate this water for a washing cycle, by pumping the water through the spray head, from whence it sprays over the articles to be cleansed and falls back into the sump to be recirculated. At the end of 30 seconds the sump 1s sufiiciently filled (in a typical machine this requires about 2 /3 gallons) and the fillrvalve is deenergized whilethe pump-motor continues to operate for a predetermined time.

. At the end ofthis time period, switch 75b opens to stop the pump-motor, and switch 75e opens to deenergize the drain valve and open it, allowing the wash water to drain from the sump. Next, the timer switches 75b, 75c, 75d and 75e are all closed. This causes the sump to refill with fresh water and the pump-motor to operate again, and at the same time causes the metering device 30 to dump a predetermined amount of sanitizer into the chamber of the machine, to mix with fresh rinse water. After approximately 30 seconds the timer switches 75c and 75d open to end the filling operation and the pump-motor continues to operate for the remainder of the rinsing portion of the cycle. At the end of this portion of the cuit and at the same time prepare for the next cycle of operation.

A pilot light is connected in parallel across the main power circuit to the drain valve, and this light is mounted on the front of the machine to inform the operator that a cycle of operations is initiated. It will be noted that the micro-switch 78 can open the power circuit to the timer mot-or and to each of the timer switches 75b, 75c and 75d, however, this switch does not control the =timer switch 75e. Thus, if the operator should open the door of the machine, and thus open switch 78, during a cycle of operation, the drain valve circuit is not disturbed, and there will not be any accidental loss of the cleansing liquid then in the machine.

The sanitizer material used in this operation is, by definition, a special class of disinfectant or bactericide intended primarily for use on food processing equipment, including dishwashing machines and the like. Typical of these sanitizers are the hypochlorites, chloramines and other organic chlorine-liberating compounds, quaternary household bleaches and disinfectants which are available 7 in grocery stores and the like, particularly the commercial product known as Clorox, which is manufactured by V The Clorox Company of Oakland, California. This product contains as'an active ingredient 5.25% by weight of sodium hypochlorite, and it has been found that this product exhibits a stable shelf life of well in excess of one year, and'thus. may be considered as. an accurate 7.

source of the necessary amount of chlorine for the present purpose.

In using this particular hypochlorite solution with a machine having a capacity of about 2 /3 gallons, as mentioned previously, approximately 12 cc. of sanitizer added to the final rinse charge of Water will provide the requisite PPM of chlorine. Thus, a device attached to a dishwashing machine of the type disclosed herein will properly sanitize articles washed therein without the need for ifinal rinse water of elevated temperatures.

Several advantages are thereby obtained. The machine can operate with what is often termed building supply hot water, which may be in the neighborhood of 120 F. to 140 F., as distinguished from the hot water supply of at least 180 P. which is otherwise required. In addition, by operating at this lower temperature, the tendency toward spotting or precipitation on the cleansed articles as they are air dried is considerably reduced. A significant reduction in tendency to spot has been noted particularly on glassware and tumblers cleansed in accordance with the invention.

Also, as the articles are air dried upon their removal from the chamber, the chlorine will escape and be dispersed in the air, in such minute quantity that it is not harmful or even noticeable. Thus, no odor or taste will remain with the cleansed articles.

The sanitizer supply apparatus, particularly as shown in FIG. 3, may be incorporated in new dishwashing equipment, or may readily be added to existing machines as an attachment. In those models of the machine where only one fill valve may be provided, this valve may be incorporated into the circuit as the valve FV-l, shown in FIG. 5, and it will be placed under the control of both timer switches 75c and 75d by connecting a jumper wire between the contacts 75c-1 and 7'5d-1. In such an arrangement, the sanitizer metering device 30 will operate at all times that the single fill valve is energized, and this merely means that a quantity of sanitizer will be added both to the wash liquid and to the rinse liquid. The device in such circumstances will use somewhat more sanitizer in operation, however this material is generally inexpensive enough to make this condition acceptable.

While the method and form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that this invention is not limited to this precise method and form of apparatus and that changes may be made the-rein without departing from the scope of the invention which is defined in the appended claim.

What is claimed is:

1. In combination with a dishwashing machine having a cleansing chamber, a sump for said chamber, means including a motor-driven pump and a spray device connected to spray cleansing liquid over soiled articles in said chamber and to recirculate the sprayed liquid from the pump through said spray device, automatically operable fill and drain valves for controlling the supply and the drainage of water to and from said sump, and a cycle control means connected to operate said valves and said pump in a desired sequence including at least one washing cycle and one final rinsing cycle during each of which fresh water is supplied to said sump; the improvement comprising a supply reservoir for concentrated chlorine containing sanitizer liquid, an automatically operable metering device having an inlet connected to said reservoir and an outlet passage opening directly into said cleansing chamber to transfer a predetermined amount of sanitizer liquid directly into said cleansing chamber for mixture with the fresh water in said sump in suflioient quantity to form an efiective sanitizer solution to be sprayed on the articles to be cleansed, said metering device including an elongated body portion providing a metering chamber beneath said inlet for gravity fill from said reservoir, a discharge chamber located below said metering chamber for gravity flow of a predetermined quantity of concentrated liquid sanitizer from said metering chamber, said outlet passage extending laterally from said discharge chamber into free communication with the cleaning chamber of said machine, a valve seat at the lower end of said metering chamber above said outlet passage, a first valve member arranged normally to close communication between said metering chamber and said discharge chamber and including .a diaphragm supporting said first valve member and extending across the bottom of said discharge chamber, a second normally open valve member between said inlet and said metering chamber and connected to operate in unison with said first valve member, said actuating connection including a solenoid on the opposite side of said diaphragm from said first valve member and connected to actuate said valve member simultaneously for closing said inlet and opening said metering chamber into said discharge chamber to provide for gravity flow of a measured quantity of sanitizer liquid into the chamber of said machine upon each actuation of said solenoid, and an actuating connection between said cycle control means and said metering device constructed and arranged to cause addition of sanitizer liquid to the fresh water in the machine during said final rinsing operation.

References Cited UNITED STATES PATENTS 2,254,269 9/1941 Clark et al. 13457 2,592,886 4/1952 Fox et al. 13495X 3,013,568 12/1961 Getc'hell et a1. 13458 3,064,662 11/1962 Given et al. 13495 3,198,387 8/1965 Kendt et al. 6817 X 3,207,373 9/1965 Dannenmann 134-58 X 2,718,481 9/1955 Tuthill 134-95 X CHARLES A. NILLMUTH, Primary Examiner.

ROBERT L. BLEUTGE, Examiner.

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