US3187767A

US3187767A - Detergent dispensing apparatus

Info

Publication number: US3187767A
Authority: US
Inventors: George E Sherrard
Original assignee: Calgon Corp
Current assignee: Calgon Corp
Priority date: 1962-12-13
Filing date: 1962-12-13
Publication date: 1965-06-08
Anticipated expiration: 1982-06-08

Description

June 8, 1965 cs. E. SHERRARD 7 3,187,767

DETERGENT DISPENSING APPARATUS Filed Dec. 15, 1962 [29 INVENTOR.

T OPNEY.

United States Patent 3,187,767 DETERGENT DISPENSING APPARATUS George E. Sherrard, Cambridge, Ohio, assignor to Calgon Corporation, a corporation of Pennsylvania Filed Dec. 13, 1962, Ser. No. 244,339 2 Claims. (Cl. 137-268) This invention relates to methods and apparatus for dispensing dry granulated detergents into dishwashing machines. 1

Prior to the present invention, it was the widespread practice in commercial, i.e. restaurant dishwashing to add dry granulated dishwashing compositions to the machine by hand in a more or less uncontrolled manner. Commercial dishwashing machines are often equipped with inexpensive conductivity meters which sound or light an alarm when the concentration of dissolved solids, generally proportional to the concentration of detergent, in the water is reduced below a predetermined minimum level. On observing the alarm, the operator adds the proper amount of dry detergent. However, in many instances, the washing operation is still not properly controlled, either because the operator is busy and does not observe the alarm or because he may add more or less detergent than is necessary.

Automatic and semiautomatic devices have been devised for controlling the addition of liquid detergents to dishwashers. Most of these also employ conductivity meters. See, for example, US. Patents 2,593,825 and 2,687,139. When the signal representing conductivity (or the reciprocal of the electrical resistance of the dishwater) reaches a predetermined value, a valve is opened or other means are activated for introducing the concentrated liquid detergent into the machine until the proper conductivity is reestablished.

Until the present invention, no satisfactory device was known for automatically or semi-automatically dispensing a detergent from its original package in the form of a dry powder or granulated composition, to maintain a desired dissolved concentration in the dishwasher or other place of use. I have invented such a method and device. My preferred apparatus is illustrated in FIGURE 1, which shows the dry detergent container, plumbing connections thereto, electrical circuitry of the conductivity meter, and valve means automatically responsive thereto. FIGURE 2 is a circuit diagram of the conductivity apparatus preferred in my invention. FIGURE 3 is a detailed illustration of the preferred fitting and dissolving device for the dry detergent container.

In FIGURE 1, the dry detergent 1 is located in a closed container 2 having a fitting 3 which accommodates incoming water conduit 4 and distributor 5. Distributor 5 extends nearly to the bottom of container 2 and is perpendicular thereto. Best results are obtained when the distance 6 between the lower end of distributor 5 and the bottom of the container is from about to about 1 inch. If this distance is not maintained, incoming water under normal or reduced water supply pressure will not dissolve the detergent around the edge of the bottom of the container.

Container 2 is also fitted at 7 with outgoing conduit 12 leading to dishwasher 8. Conductivity cell 9 is immersed in the water of the dishwasher, and is electrically connected to conductivity meter 10, which in turn is connected so as to energize solenoid valve 11 when the conductivity of the dishwasher is not in the proper range. Solenoid valve 11 operates to open or shut ofi the flow of water from a source 13 into container 2 accordingly.

FIGURE 2 is a circuit diagram of my preferred conductivity meter and relay operable thereby. In this circuit, power from source 20 is introduced through transformer 21, to bridge 22. Bridge 22 comprises fixed resistors 23 and 24, normally adjustable resistor 25 and conductivity cell 26. The output of the bridge is transmitted through transformer 27 to thyratron 28, where it controls the flow of current to solenoid-operated relay 29. When the resistance reaches a predetermined maximum, indicating that the alkalinity of the dishwater is below the desired minimum, the thyratron causes the relay to operate, completing the circuit to valve 30, which is then opened to permit the flow of water into the container of granulated detergent.

FIGURE 3 illustrates the dissolving device in detail. The top 41 of the container or drum of detergent is fitted with a plastic cup 40 including an orifice 42 having threads 43. Washer or gasket 44 seats on a horizontal circumferential rim 45. Plastic fitting insert 46 is placed directly on washer 44. It is a solid disc of plastic having two threaded holes 47 and 48 into which

fittings

49 and 50 are inserted.

Fittings

49 and 50 are adjusted to receive water pipes or tubing.

Distributor 5 is a hollow tube which communicates with fitting 49 and as explained with reference to FIGURE 1, extends nearly to the bottom of the container. It is preferably provided with

horizontal slits

51 and 52. The tip 53 may be closed or partly open.

Slits

51 and 52 are no more than an inch from the bottom of the container, preferably no more than about one-half inch. Efliciency maybe improved by inclining them slightly downward (i.e. 57 off the horizontal) directly toward the outer edge of the container bottom.

Slits

51 and 52 may be replaced by one or more orifices oriented in downward, horizontal, or partly downward, partly horizontal directions. If more than a few small orifices are used, they should be disposed to emit jets of water more or less radially so that the entire circumference of the container bottom will be reached. If only one orifice is used, it should be large and directed at the container floor. Orifices directed upwardly do not efiiciently serve my purposes. In no case should either horizontal or downward-directed orifices be confined to an area of the distributor more than an inch from the container bottom.

The operator will know the container is empty when the conductivity fails to be restored after the device dispenses for an abnormally long period. A new container may then very easily be installed.

It will be apparent to those skilled in the art that more or less concentrated solutions of detergent will be dispensed with my apparatus at different stages in the removal of the detergent from the container, and depending on the temperature of the water, the pressure, length of time the valve is open, composition of the detergent, etc. However, regardless of such variables, my device will deliver the correct amount of detergent since it is measured by conductivity.

A semi-automatic system can be employed simply by replacing valve 30 (FIG. 2) or 11 (FIG. 1) with a warning bell, light or the like. The operator will then turn a valve manually to admit detergent to the dishwasher until the desired conductivity is restored.

The composition of the detergent is significant in the normal use of my invention. Not only should its overall solubility be in a range which lends itself to practical use, but there must be no ingredients which are appreciably more or less soluble than the other ingredients. In order to assure that the proper detergent mixture is entering the dishwasher at all times, the ingredients should dissolve at approximately the same rates. Examples of compositions which are excellent in my invention are those described in US. Patent 2,756,214. A composition consisting essentially of from about 20% by weight to about by weight sodium tripolyphosphate together with 3. from about80% to about 20% by weight hydrated chlorinated trisodium orthophosphate is excellent for use in my invention.

It will be apparent to those familiar withthe art that my invention comprises a new detergent package. The package consists of a closed container filled with dry powdered or granular detergent and having a perpendicular tubular distributor substantially as described. 1

Having thus described my invention, it is to be distinctly understood that the invention is not limited to the examples and illustrations given herein, but may be otherwise varied within the scope of the following claims.

1. A package of dry detergentv suitable for dispensing detergent of substantially constant composition in the dissolved form directly into a dishwasher in response to a conductivity control, comprising a closed cylindrical container, detergent therein consisting essentially of about 20% to about 80% sodium tripolyphosphate and about.

80% to about 20% chlorinated trisodium orthophosphate, a fixture in the top of said container including outlet means and inlet means comprising a tubular Water distributor adapted to be connected to an external water source and extending downwardly to a point near the bottom of said container, said distributor having at least two orifices for causing the ejection of water in different directions approximately parallel to the base of said container.

2. The combination comprising ,7 (a) a package of dry detergent suitable for dispensing detergent of substantially constant composition in the dissolved form directly into a dishwasher in response to a conductivity control, comprising atclosed cylindrical container, detergent therein consisting essentially of about 20% to about sodium tripolyphosphate and about 80% to about 20% chlorinated trisodium orthophosphate, a fixture in the top of said container including outlet means and inlet means comprising a tubular water distributor adapted to be connected to an external water source and extending downwardly to a point near the bottom of said container, said distributor having at least two orifices for causing the ejection of water in difierent directions approximately parallel to the base of said container, and V (b) dishwater conductivity regulating apparatus for 7 measuring the conductivity of dishwater containing dissolved detergent delivered from said package and controlling the water supply to said distributor in response to said conductivity.

References Cited by the Examiner UNITED STATES PATENTS 1,197,337 9/16 Bonfield 23-267 1,350,175 8/20 O'Connor 13726-8 1,988,000 1/35 Estler 23-267 2,419,845 4/47 Merrick 23-267 2,490,634 12/49 Keene 137-93 2,573,576 10/51 Klumb 23267 2,756,214 7/53 Albrecht 25299 M. CARY NELSON, Primary Examiner.

MARTIN P. SCHVJADRGN, Examiner.

Claims

1. A PACKAGE OF DRY DETERGENT SUITABLE FOR DISPENSING DETERGENT OF SUBSTANTIALLY CONSTANT COMPOSITION IN THE DISSOLVED FORM DIRECTLY INTO A DISHWATER IN RESPONSE TO A CONDUCTIVITY CONTROL, COMPRISING A CLOSED CYLINDRICAL CONTAINER, DETERGENT THEREIN CONSISTING ESSENTIALLY OF ABOUT 20% TO ABOUT 80% SODIUM TRIPOLYPHOSPHATE AND ABOUT 80% TO ABOUT 20% CHLORINATED TRISODIUM ORTHOPHOSPHATE, A FIXTURE IN THE TOP OF SAID CONTAINER INCLUDE OUTLET MEANS AND INLET MEANS COMPRISING A TUBULAR WATER DISTRIBUTOR ADAPTED TO BE CONNECTED TO AN EXTERNAL WATER SOURCE AND EXTENDING DOWNWARDLY TO A POINT NEAR THE BOTTOM OF SAID CONTAINER, SAID DISTRIBUTOR HAVING AT LEAST TWO ORIFICES FOR CAUSING THE EJECTION OF WATER IN DIFFERENT DIRECTIONS APPROXIMATELY PARALLEL TO THE BASE OF SAID CONTAINER.