US2747588A - Dishwashing machine - Google Patents

Description

May 29, 1956 w. c. BONNER DISHWASHING MACHINE 5 Sheets-Sheet 1 Filed May 20, 1953 W 0. Bo 22y W qm flioz azegys May 29, 1956 Filed May 20, 1953 5 Sheets-Shet 2 May 29, 1956 Filed May 20, 1953 W. C. BONNER DISHWASHING MACHINE 5 Sheets-Sheet 3 l 44 I I 5" 3 i v Q I. a if? I; 4 I

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Application May 20, 1953, Serial No. 356,289

14 Claims. (Cl. 134-93) This invention relates to dishwashing machines and pertains in particular to apparatus for controlling the concentration of disinfecting and cleaning agents in such machines.

In dishwashing machines of the types used in restaurants and institutions, the wash Water is ordinarily recirculated and used a number of times. The machine has a reservoir which is initially filled with water containing a certain amount of detergent and other cleaning or disinfecting agents. The wash Water is circulated by a pump from the reservoir to nozzles which direct a spray over the dishes. The used water subsequently falls back into the reservoir. Each batch of dishes is rinsed, after the washing operation, by a spray of fresh rinse water which alsofalls into the reservoir. As the fresh rinse water is admitted, a certain amount of the water in the reservoir is drawn off, or runs off through an overflow, so that the level of the wash water in the reservoir remains substantially constant. In order to maintain an adequate concentration of cleaning and disinfecting agents in the Wash water, additional amounts of these materials must be supplied to the reservoir from time to time. In commercial operations, the concentration of these agents in the wash water should be controlled fairly accurately, as too low a concentration results in improper cleaning and too high a concentration is wasteful of the cleaning and disinfecting materials, and is likely to leave an objectional residue on the dishes.

In many localities, restaurants and other institutions serving the public are required by law to maintain a minimum concentration of germicide such as chlorine in the washwater of their dishwashing machines. The chlorine may be supplied in the form of concentrated sodium hypochlorite solution, or soluble tablets of calcium hypochlorite. Typical requirements for chlorine content in the water vary from to 100 parts per million. The hypochlorite cannot be mixed with most of the common detergents before adding to the wash water as mixing of the concentrated solutions would result in release of a considerable amount of the chlorine as gas.

The object of this invention is to provide a dispenser for detergents and germicides which is adaptable for installation on conventional dishwashing machines, which automatically introduces a quantity of each material which is directly proportional to the amount of fresh rinse water admitted to the machine during operation, which accurately maintains a desired concentration of these materials in the wash water, which introduces the detergent and germicide materials separately and insures thorough mixing before the wash water reaches the dishes, which allows for independent adjustment of the concentration of the materials over a wide range, and which may be operated with a minimum of attention and expense.

In the drawings illustrating the invention;

Fig. 1 is a front elevation of a detergent dispensing ice apparatus constructed according to the invention, installed on a conventional dishwashing machine,

Fig. 2 is a plan view somewhat enlarged, of the dispensing apparatus,

Fig. 3 is an enlarged side elevation of the dispensing apparatus,

Fig. 4 is an enlarged cross-section taken along line 4-4 of Fig. 3,

Fig. 5 is a cross-section taken along line 55 of Fig. 4, and

Fig. 6 is a cross-section taken along line 6--6 of Fig. 4.

Fig. 7 is a plan view of a modification of one of the dispensing units, and

Fig. 8 is a cross-section along line 88 of Fig. 7.

The dispenser is illustrated in Fig. 1 as installed on a conventional commercial dishwasher of the feed-through type having a casing 10 divided by a waterproof partition into a lower compartment 12, in which are housed the motor, pump and other operating mechanisms of the machine, and an upper compartment 13, through which runs a conveyor table 14. The table supports racks 15 holding dishes 16. Below the conveyor is a reservoir 17 which, during operation, is filled to the level of overflow pipe 18. In the end walls of the upper compartment are openings 19 and 20 partially covered by flexible waterproof curtains 21 and 22. The space above the conv'eyor table is also divided by flexible waterproof curtains 23 and 24 into an idle space 25, where the racks of soiled dishes are inserted, a washing space 26, and a rinsing space 27. The racks of soiled dishes are inserted into the idle space, each rack pushing those ahead of it into the washing space and rinsing space. Alternatively, the racks may be advanced by a suitable drive mechanism (not shown). In the washing space are located the washing nozzles 28 which spray the dishes with water circulated up from reservoir 17 by a suitable pump and piping sys-- tern (not shown). One or more rinsing nozzles 45 connected to a fresh hot water supply by pipe 29 through valve 34 are mounted in the rinsing compartment.

The dispenser is supported on a base plate 30 which is mounted on the top of the dishwasher housing. A vertical pipe 31 runs through the base plate, where it is se-- cured by lock nuts 32 and 33, and through the housing,v and is connected to the feed pipe 29 of the rinsing nozzles.v A second vertical pipe 35 is secured to the base plate by lock nuts 36 and 37 and extends through the housing into: the washing compartment 26.

If preferred, base plate 30 may be used only for ship-- ping the unit and removed for installation. In that case, pipes 31 and 35 are mounted directly on the dishwasher casing, the casing being clamped between the mounting. nuts. A second plate 38 is supported on pipes 31 and 35. The whole assembly is attached to the housing 11)- by means of clips 39 and 40 which may be screwed to the housing. The upper ends of pipes 31 and 35 are stopped by caps 41 and 42 respectively A tank 43, provided with a removable cover 53, is mounted on plate 38 and holds the detergent tablets 44. These tablets may consist of any suitable detergent, or mixture of deter.- gents, such as tetrasodium phosphate, trisodium phosphate, and metasilicate, compressed into briquettes of the proper shape and size to fit the dispensing tank. The bottom of tank 43 is provided with bosses 46 which hold the tablets ofi the bottom to allow room for water under the bottom tablet. tubing, is connected to pipe 31 and discharges into a manifold 48 which has openings 49 leading to the interior of tank 43. A manually operated valve 50 is provided for: regulatingthe flow through tube 47. On the opposite side of tank 43 is a discharge. pipe 51 which leads intc A conduit 47, preferably of flexible.

' chamber 60 above the level of partition 58.

pipe 35. Pipe has an extension 52 on its lower end leading down through washing compartment 26 into reservoir 17.

When the machine is first put into operation the rinse valve is opened for a short time and by-pass valve is opened until the level of water in -tank-43 reaches the bottom of pipe 51. already filled with water containing the desired amount of detergent and germicide. Thereafter the rinse water valve 34-is opened periodically, either by hand or by an automatic timing device, to rinse dishes after each Washing cycle. The additional flow of water through tube 47 into tank 43 forces water from the tank out through pipe 51,-carrying dissolved detergent down through pipe 52 into the reservoir 17.

When the rinse water valve is shut ofi after a rinsing cycle, the detergent solution continues to tlow through pipe 52 until the level in tank 43 falls below pipe 51. When the machine is in constant operation tank'43 re tains water up to the bottom of pipe 51, so that the lowest detergent tablet is continually soaked and the residual water becomes substantially saturated with detergent. On each rinsing cycle, the additional Water entering through tube 47 forces an equal amount of detergent solution out through pipee'i, so that the amount of detergent added to the Wash water is at all times proportionate to the amount of fresh rinse water admitted. By adjusting valve 59, the proportion of detergent admitted may readily be regulated so as to maintain the desired concentration of detergent in the wash water in reservoir 17. The arrangement of manifold 48 and orifices 49 distributes the incoming flow so as to prevent undue local washing away of the upper tablets, and the spacing of the lower tablet from the bottom of the tank causes each tablet in succession to dissolve gradually from the bottom. From time to time, an additional tablet may be placed on top of the stack without disturbing the operation of the device.

Mounted on plate 30 is a cylindrical tank 55, the wall of which surrounds a second cylindrical tank 56. The wall of tank 56 is spaced from that of tank so as to form an outer compartment 57. Tank 56 has a horizontal partition 58 which divides it into a lower chamber 59 and an upper chamber 69. The partition has a number of holes 61 through which liquid may flow. A pipe 62 communicates with the bottom chamber 59 and runs down through the rinsing compartment 27 into reservoir 17. Tank 56 has a'ring of holes 63 leading into the upper In operation chamber 69 is filled about to the level of holes 63 with tablets 64 of calcium hypochlorite or other soluble material suitable for supplying germicide. Vents 65 in the wall of tank 56 above holes 63 provide for the escape of chlorine gas. A cover 66 may be provided on the tank. A guard ring 72, having vent holes 73 too small toallow passage of one of the tablets 64, may be placed over the opening between tanks 55 and 56 to prevent accidental insertion of the tablets into the wrong opening. A by-pass line 67, preferably, like by-pass 47, of flexible tubing, connects pipe 31 with compartment 57, entering the compartment near the bottom. A manual valve 68 controls the flow through line 67. When the dishwasher is first put into operation, the rinse valve is opened for a short time, as previously described, and valve 68 as well as valve 50 is opened, so that some of the rinse water is by-passed through tube 67 into compartment 57. When compartment 57 is filled to the level of holes 63, and tank 43 is filled to the bottom of pipe 51, the dispenser is ready for automatic operation; On each rinsing cycle the additional water entering compartment 57 causes an overflow of equal amount through holes 63. The water thus entering chamber flows down over the chlorine tablets 56,

It is assumed that reservoir 17 is.

through holes 61 and pipe 62, carrying chlorine solution down into reservoir 17. The chlorine tablets, unlike the detergent tablets, should not be subjected to continuous soaking, .as they disintegrate too readily and would give olt considerable chlorine as gas. With the arrangement here showii, the water admitted into chamber 60 drains out completely at the end of the rinsing cycle, leaving the chlorine tablet to dry. An overflow pipe 70 is connected to an outlet 71 in tank 55 and leads to pipe 35. The purpose of this overflow pipe is to remove excess water in case holes 63 become plugged, and thus prevent spilling of the chlorine solution on the outside of the dishwasher.

Figs. 7 and 8 illustrate a modification of the germicide dispensing unit. In this modification a conduit 74 is cut through the bottom 76 of tank 55 and has an upward sloping portion 77 leading to an orifice 78 in the bottom, and to one side of compartment 59. An additional by-pass line 75, leading from standpipe 31 discharges into conduit 74. The water discharged through orifice 78, when the rinse water valve is open, washes the walls of compartmeat 59 and the partition 58, and prevents clogging of holes 61 and formation ofsediment in compartment 59. The water entering through pipe 67 overflows through holes 63 and passes down over tablets 64 and through holes 61 as previously described, and the water admitted through both by-pass lines 67 and drains out through pipe 62.

If desired, the dispensing apparatus may be used in initially filling the tank. The proper amounts of detergent and chlorine bearing material for the capacity of the reservoir are inserted in tanks 43 and 56 respectively and the rinse valve opened to fill the reservoir. Valves 50 and 68 are opened sufliciently to insure a fast enough flow to dissolve all the detergent and hypochlorite by the time the reservoir is full. Thereafter the detergent and hypochlorite are replenished and valves 50 and 68 set to maintain the desired concentration, and the dispenser operates as previously described. If desired, also, either valve 56 or valve 68 may be closed and the dispenser used to supply only one of the solutions.

It will be noted that direct contact between the concentrated solutions and the dishes is prevented by extending the supply pipes 52 and 62 down into the reservoir.

This arrangement also prevents back splash of wash water.

into the dispenser. The spacing of the pipes insures that the two solutions are diluted by the wash water before they mix.

What is claimed is:

l. A device for supplying cleaning agents to a dishwashing machine having a water supply pipe comprising: a first tank adapted to contain a soluble cleaning agent mounted above said machine; a conduit communicating with said pipe and discharging into said tank; an opening in the side of said tank spaced from the bottom thereof; a discharge pipe leading from said opening down into the machine; a second tank mounted above said machine; a wall dividing said second tank into an inner compartment adapted to hold a soluble disinfecting agent, and an outer compartment; a second conduit com-- municating with said supplypipe and discharging into the lower part of said outer compartment; one or more openings in said wall above the level of discharge of said second conduit; and an outlet in the bottom of said inner compartment communicating with the interior of the machine.

2-. A device as described in claim 1, each of said conduits being provided with a valve for independently controlling flow therethrough.

3. A device for supplying cleaning agents to a dishwashing machine having a water supply pipe comprising: a first standpipe mounted above said machine and having its lower end connected to said supply pipe; a second standpipe mounted above said machine and having a lower end opening into said machine; a first tank mounted between said standpipes above said machine, and adapted to hold soluble detergentpa first by-pass conduit connected to said first standpipe and discharging into said first tank; an opening in the side of' said first tank above the bottom thereof; a discharge pipe leading from said opening to said second standpipe; a

second tank mounted between said standpipesnbove said machine; a wall divi ing said second tank into an inner compartment adapted to hold a soluble disinfecting agent and an outer compartment; 21 second by-pass conduit connected to said first standpipe and discharging into the lower part of said outer compartment; one or more openings in said wall above the point of discharge of said second conduit; and an outlet in the bottom of said inner compartment communicating with the interior of said machine.

4. In a dishwashing machine having a rinse-water supply pipe, equipped with a control valve and leading to a rinsing nozzle, a device for supplying cleaning agents to the machine comprising: a first tank mounted above said machine and adapted to hold a soluble cleaning agent; a first by-pass conduit communicating with said supply pipe between said valve and said nozzle and discharging into said tank; an opening in the side of said tank above the bottom thereof; a discharge pipe leading from said opening down into the machine; a second tank mounted above said machine; a wall dividing said second tank into an inner compartment adapted to hold a soluble disinfecting agent and an outer compartment; a second by-pass conduit communicating with said supply pipe between said valve and said nozzle and discharging into the lower part of said outer compartment; one or more openings in said wall above the level of discharge of said second conduit; and an outlet leading from the bottom of said inner compartment communicating with the interior of said machine.

5. Apparatus as described in claim 4, each of said conduits being provided with a control valve for independently controlling the flow therethrough, thereby independently varying the proportion of cleaning agent and disinfecting agent admitted when said rinse valve is open.

6. In a dishwashing machine having a wash water reservoir, a space for dishes above said reservoir, a partition dividing said space into a washing space and a rinsing area, and a water supply pipe, a device for sup plying cleaning agents to the machine comprising: a first tank mounted above said machine and adapted to hold a soluble cleaning agent; a by-pass conduit connected to said supply pipe and discharging into said first tank; an opening in the side of said first tank above the bottom thereof; a second tank mounted above said machine; a wall dividing said second tank into an inner compartment adapted to hold a soluble disinfecting agent, and an outer compartment; a second by-pass conduit connected to said supply pipe and discharging into the lower part of said outer compartment; one or more openings in said Wall above the point of discharge of said second conduit; a first discharge pipe leading from said opening in said first tank down into said reservoir on one side of said partition; and a second discharge pipe leading from the bottom of said inner compartment down into said reservoir on the other side of said partition.

7. In a device for supplying cleaning agents to a dishwashing machine; a generally cylindrical tank having a fiat bottom and a side wall, adapted to contain soluble detergent tablets; a confined chamber disposed part way up on the side wall of said tank; a series of apertures disposed in a horizontal plane in said side wall and communicating with said chamber; a water inlet pipe arranged to discharge into said chamber substantially tangentially to the side of the tank; an opening in said side wall opposite said chamber, said opening being spaced from said bottom but below the level of said apertures; and a discharge pipe leading from said opening down into the machine.

8. A device as described in claim 7, said tank having upward protuberances on the bottom for spacing said tablets away from the bottom.

9. In a device for supplying cleaning agents to a dishwashing machine; a tank having a flat bottom and spaced concentric cylindrical walls forming an outer and an inner compartment; a perforated horizontal partition dividing said inner compartment into an upper compartment adapted to hold tablets of a soluble disinfecting agent, and a lower compartment; a water inlet pipe discharging into the lower part of said outer compartment; a series of holes disposed in a horizontal plane in the inner wall of said tank above said partition and higher than the point of discharge of said inlet pipe; and an outlet in the bottom of said lower compartment communicating with the interior of said machine.

10. A device as described in claim 9 having an overflow pipe communicating with said outer compartment above the level of said holes and leading down into the machine.

11. A device as described in claim 9 having a horizontal conduit in the bottom of said tank, said conduit having a sloping portion terminating in an orifice opening into said lower compartment adjacent said wall, and a second water inlet pipe communicating with said conduit.

12. A device for supplying cleaning agents to a dishwashing machine having a water supply pipe comprising: a first tank adapted to contain a soluble cleaning agent mounted above said machine; a conduit communicating with said pipe and discharging into said tank; an opening in the side of said tank spaced from the bottom thereof; a discharge pipe leading from said opening down into the machine; a second tank mounted above said machine; a perforated partition dividing said second tank into an upper compartment, adapted to hold a soluble disinfecting agent, and a lower compartment; means for conducting water from said pipe to said second tank; and an outlet in the bottom of said lower compartment communicating with the interior of the machine.

13. In a dishwashing machine having a wash water reservoir, a space for dishes above said reservoir, a partition dividing said space into a washing space and a rinsing area, and a water supply pipe, a device for supplying cleaning agents to the machine comprising: a first tank mounted above said machine and adapted to hold a soluble cleaning agent; a bypass conduit connected to said supply pipe and discharging into said first tank; an opening in the side of said first tank above the bottom thereof; a second tank mounted above said machine; a perforated wall dividing said second tank into an upper compartment, adapted to hold a soluble disinfecting agent, and a lower compartment; means for conducting water from said supply pipe to said second tank; an outlet in said lower cornpartment, a first discharge pipe leading from said opening in said first tank down into said reservoir on one side of said partition; and a second discharge pipe leading from said outlet down into said reservoir on the other side of said partition.

14. In a device for supplying cleaning agents to a dishwashing machine; a tank having a flat bottom and a cylindrical wall; a perforated partition dividing said tank into an upper compartment adapted to hold a soluble disinfecting agent, and a lower compartment; a water inlet conduit terminating in an orifice opening into said lower compartment, said conduit being adapted to discharge water substantially tangentially to said wall; and an outlet in the bottom of said lower compartment communicating with the interior of the machine.

Miller Apr. 17, 1943 Woodson Sept. 26, 1950

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