US 3680784 A
In a dishwashing machine wherein wash water containing detergent and a wetting agent is re-circulated from a sump over dishes at a washing station, rinse water containing a wetting agent is sprayed over dishes at a rinse station, and at least some of the rinse water is drained for make-up to the wash water sump, a feed system is provided for delivering a predetermined, regulatable ratio of detergent and wetting agent to the sump at start-up, and another predetermined regulatable amount of detergent to the sump during each rinse cycle so as to maintain in the wash water a constant ratio of detergent to wetting agent and constant concentration thereof in the wash water.
Claims available in
Description (OCR text may contain errors)
United States Patent Fakes [451 Aug. 1, 1972  DETERGENT AND WETTING AGENT DISPENSER FOR DISHWASHING MACHINES  Inventor: Roger E. Fakes, Memphis, Tenn.  Assignee: Auto-Chlor System, Memphis, Tenn.
 Filed: Jan. 27, 1971 ] Appl. No.: 110,052
 US. Cl ..239/l26, 134/57 D, 222/135  Int. Cl. ..B05b 9/00  Field of Search ..239/l26, 127; 222/132, 135,
3,160,317 12/1964 Hambro ..2222/135 X 3,370,597 2/1968 Fox ..134/58 D 3,478,757 11/1969 Tuthill ..l34/57 D Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Thomas C. Culp, Jr. Attorney-James l-l. Littlepage  ABSTRACT In a dishwashing machine wherein wash water containing detergent and a wetting agent is re-circulated from a sump over dishes at a washing station, rinse water containing a wetting agent is sprayed over dishes at a rinse station, and at least some of the rinse water is drained for make-up to the wash water sump, a feed system is provided for delivering a predetermined, regulatable ratio of detergent and wetting agent to the sump at start-up, and another predetermined regulatable amount of detergent to the sump during each rinse cycleso as to maintain in the wash water a constant ratio of detergent to wetting agent and constant concentration thereof in the wash water.
4 Claims, 1 Drawing Figure  References Cited UNITED STATES PATENTS 2,903,248 9/1959 Walker ..137/566 X 2,852,635 9/1958 Reed ..222/135 X 3,233,651 2/1966 Smith ..239/126 X 2,945,445 7/1960 Smith et al. ..222/255 X 2,197,382 4/1940 Murphy ..l37/566 2,843,137 7/1958 Federighi et a1. ....134/57 D VARIABLE PRESSURE SWITCH PATENTEDAUG 1 1912 HEATER SWITCH INVENTOR ROGER E. FAKES DETERGENT AND WETTING AGENT DISPENSER FOR DISHWASHING MACHINES FIELD OF INVENTION Cleaning and liquid contact with solids, with plural means for supplying and/or applying different fluids respectively, with ordered fluid applying means.
KNOWN PRIOR ART Murphy US. Pat. No. 2,197,382; Sherrard U.S. Pat. No. 3,187,767; Fox US. Pat. No. 3,370,597; Tuthill US. Pat. No. 3,478,757.
OBJECTS It has been known heretofore, in the automatic dishwashing machineart, to provide means for feeding a washing agent, such as soap or detergent, into the wash water line each time the wash water line is opened (Murphy, supra), or simply to feed the wash water through a solid detergent supply container (Sherrard, supra); and Tuthill (supra) discloses separate pumps for supplying detergent to a wash water sump, rinse additive to the rinse water line, and time control means for assuring that at least some detergent will be added to the wash water sump each time the rinse cycle is initiated. The present invention is an improvement over the prior art in that it is intended to provide a detergent and wetting agent supply system utilizing separate supply reservoir for detergent and wetting agent and for variable delivery pumps, each one having adjustable to provide desired amounts of fluid delivered while they are operating. By this system, two of the pumps are so adjusted as to deliver detergent and wetting agent to the wash water sump in predetermined ratio and concentration so long as the fill water control valve is open, and the other two pumps are so adjusted as to supply wetting agent to the rinse water supply line, in predetermined amount, so long as the rinse water control valve is open, and to supply detergent to the wash water sump in predetermine amount so long as the rinse water controlvalve is open. By these means, it is intended to provide that the wash water, at start-up,
will always have the desired concentration and ratio of veyor dishwashing machine 2 which has an enclosure 4 through which the dishes to be washed are transported, usually in racks, on a conveyor, not shown. In the present example, it will be assumed that the dishes move through enclosure 4 from right to left and, upon entering, are sprayed with wash water from heads 6, 6. The wash water is supplied by a recirculating pump 8 from a wash water sump 10. Before leaving enclosure 4, the dishes are rinsed with rinse water from spray heads 12, 12'. The rinse water is derived from acity water supply pipe 14 through pipe 13 and via heater 16 in which the water temperature is raised to about 180.
Before start-up, wash water sump 10 is initially filled with water from the city water supply line l4'via a fill water supply line 18. An initial quantity of fill water is deposited into wash water sump 10 by opening fill valve 20; and, when the dishes have been washed and moved to the rinsing station, rinse water valve 22 is opened. At least part of the rinse water drains or may otherwise be fed into the wash water sump 10 in order to make up wash water losses due, for example, to evaporation or spillage. Many other types of machines with more complex cycles of operation are well known in the art, the common characteristic to which this invention is addressed is that part or all of the rinse water finds it way into the wash water sump; and for washing the dishes a detergent, which generally includes phosphate and an alkali and perhaps chlorine, and a wetting agent are used; and for rinsing a wetting agent is introduced into the rinse water. Ordinarily, a single solution consisting of phosphate, and alkali and chlorine can be maintained, but the wetting agent and the chlorine are incompatible; and, hence, the wetting agent must be maintained in a separate solution.
The specific problem arises from the make-up of the wash water with rinse water. Since the rinse water has in it only the wetting agent, after series of wash and rinse cycles the wash water would normally have in it ample wetting agent, but it would become depleted of detergent. In typical'operation of the subject system, and with appropriate adjustment ofsolution strengths, the machine for washing would typically use 1 part wetting agent derived from a wetting agent supply 24 to 5 parts detergent derived from a detergent supply 26, the the concentration of wetting agent, by gallon of water for washing, might be different from the concentration for rinsing.
In order to maintain proper balance and concentration of wash and rinse additives, the subject system utilizes four variable delivery pumps 28, 30, 32 and 34 operated by electric motors, not shown. These pumps can be any one of a number of different types, for example, piston pumps of adjustable stroke length and, if desired, the electric motors which drive them may be of variable speed. Variable delivery pump 28 has an intake line 36 from wetting agent supply 24 and a delivery line 38 running to rinse water supply line 13 down stream of rinse water valve 22. Pump 28 must be capable of pumping against a head of water pressure in line 13. Variable delivery pump 30 has intake line 42 from the wetting agent supply 24 and a delivery line 44 connected via branch line 46 to a common delivery line 48 leading to the wash water sump 10. Variable delivery pump 32 has an intake line 50 leading from detergent supply tank 26 and a delivery line 52 connected via branch 46 to common delivery line 48; and variable delivery pump 34 has an intake line 54 leading from detergent supply 26 and a delivery line 56 leading to common delivery line 48. Thus, pump 28 pumps wetting agent into rinse water supply line 13; pump 30 pumps wetting agent into wash water sump l0; and pumps 32 and 34 both pump detergent into wash water sump 10.
To the rinse water supply line 13 downstream of rinse valve 22 is connected a pressure responsive switch 58 which closes in response to pressure in the rinse water supply line. To the fill water supply line downstream of fill water valve 20 is connected a similar switch 60 which closes when fill water is supplied to the wash water sump 10. The electrical circuits for energizing the pump motors are as follows: One side 62 of an electric power line is connected to one terminal of each of the variable delivery pump motors. The other side 64 of the power line is connected via lead 66 through pressure switch 58 and via branch line 68 and 70 to the other terminals of pumps 28 and 32. The second side 64 of power supply line is connected via lead 72 through pressure responsive switch 60 and, thence, to line 74 and branches 76 and 78 to the other terminals of the motors for the variable delivery pumps 30 and 34.
The operation of the system is as follows: The startup fill valve 20 is open to supply wash water to sump l and, when wash water flows, switch 60 closes a circuit to the motors of variable delivery pumps 30 and 34 which pump wetting agent and detergent into wash water sump 10, so long as fill water flows. Subsequently, when rinse valve 22 is open, pressure responsive switch 58 closes the circuit to motor for variable delivery pump 28 which pumps wetting agent into rinse line 13. However, at the same time, switch 58 also closes the energizing circuit via line 70 to the motor for variable delivery pump 32 and the latter pumps detergent into wash water sump so as to maintain the proper balance of detergent with respect to the wetting agent-enriched rinse water which enters sump 10. By the use of the four pumps whose delivery can be adjusted, the proper portions of wetting agent and detergent can be provided for the initial fill; the amount of wetting agent injected into the rinse water line can be adjusted; and the amount of detergent in troduced as make-up into the wash water sump can be adjusted with respect to the rinse agent supplied via the rinse supply.
I. In a dishwashing machine having a wash water sump, a wash water spray head, a pump for re-circulating wash water to the wash water spray head, a fill water supply line for the sump, a rinse water spray head, a rinse water supply line for the rinse water spray head, and fill water and rinse water control valves for said supply lines, and separate reservoirs for wetting agent and detergent, the improvement which comprises a first variable delivery pump having an intake line leading from the wetting agent reservoir and an output line leading into the rinse water supply line,
a second variable delivery pump having an intake line leading from the wetting agent reservoir and an output line leading to the sump,
third and fourth variable delivery pumps each having an intake line leading from the detergent reservoir and an output line leading to the sump,
each of said variable delivery pumps being driven by an electric motor normally open electrical circuits for energizing said motors,
a first switch for closing the circuits to the motors for said second and fourth variable delivery pumps in response to opening of said fill water control valve, and
a second switch for closing the circuits to the motors for said first and third variable delivery pumps in response to opening of said rinse water control 2. iii? combination claimed in claim 1, said first switch being pressure responsive and having sensors disposed in said fill water line downstream of the fill water control valve.
3. The combination claimed in claim 1, said second switch being pressure responsive and having sensors disposed downstream of the rinse water control valve.
4. The combination claimed in claim 1, said switches being pressure responsive and having sensors disposed in said lines downstream of said control valves.