GB Patent 971357 - Dishwashing machine and operational cycle therefor

Claims

WHAT WE CLAIM IS: -

1 Automatic dishwasher, comprising operating means for effecting a washing 105 operation in a washing compartment supplied with water through a flow conduit provided with a valve, wherein a closed liquid receptacle is interposed in the flow conduit between the valve and the washing com 110 partment and provided with means for heating the contents of the receptacle, timer means being provided for energization of the heating means to heat the water as it passes through the receptacle, and said timer 115 means effecting periodic opening and closing of the valve to reduce the average rate of flow through the receptacle and thereby increase the temperature of water delivered to the washing compartment for a washing 120 cycle.

2 Automatic dishwasher as set forth in Claim 1, wherein the portion of the flow conduit between the receptacle and the washing compartment communicates with 125 the upper portion of the receptacle, the timer means being adapted to initiate opening of the valve and energization of the heating means for a predetermined period.

Is 971,357 3 Automatic dishwasher as set forth in Claim 2, including means responsive to temperatures above a predetermined maximum during the washing cycle to override the timer means and hold the valve open for full flow of water through the receptacle until the temperature therein is lowered at least to the predetermined maximum and the temperature responsive means becomes inactive and returns the control of the valve to the timer means.

4 Automatic dishwasher as set forth in Claim 1, 2 or 3, including control means including an electric circuit for regulating the sequence of operation of the dishwasher, the timer means forming part of said control means and including switches connected in the electric circuit and operable to activate said operating means, open the valve and energize the heating means for a predetermined period for a pre-wash cycle, the means for effecting said periodic opening and closing of the valve during the main washing cycle including a cam operatively connected with the timer means and one of said switches.

Automatic dishwasher as set forth in Claim 4, wherein the timer means is adpated after said main washing cycle to close the valve with the heating means energized to convert the water remaining in the receptacle to steam for delivery to the washing compartment.

6 Automatic dishwasher as set forth in Claim 5, including means responsive to temperature in the receptacle and operative in response to a predetermined temperature above the boiling point of water to arrest the operation of the heating means.

7 Automatic dishwasher as set forth in Claim 5 or 6, wherein the timer means is adapted to actuate the switches for activating the operating means, opening the valve and maintaining the heating means active for rinsing cycles subsequent to the main washing cycle and prior to the steaming cycle.

8 Automatic dishwasher as set forth in any one of Claims 4-7, wherein said washing compartment has a bottom and means for holding articles to be washed in spaced relation to said bottom, a drain fitting being provided in said bottom and having a portion extending upwardly therefrom and terminating in an opening at maximum liquid level and a valve controlled opening at the bottom for draining liquid from the washing compartment, while said operating means includes impeller means driven by an electric motor for directing liquid from adjacent said bottom against the articles, members in said timer means actuating the switches to close the fill valve, stop the electric motor and open the drain fitting valve to empty the washing compartment at the end of the main washing cycle.

9 Automatic dishwasher as set forth in Claim 8 including a float valve responsive to liquid in the washing compartment at a level above the predetermined maximum level to interrupt the electric circuit to close the fill valve and arrest the operation of the heating means.

Automatic dishwasher as set forth in Claim 8 or 9, including a door providing access to the washing compartment and means in the electric circuit ahead of the timer means to complete the circuit thereto when the door is closed and to interrupt the circuit to stop all operations of the dishwasher when the door is moved from closed position.

11 Automatic dishwasher as set forth in Claim 8, 9 or 10, including means associated with the impeller means for varying the direction of the liquid from the impeller means over the interior of the washing compartment.

12 Automatic dishwasher, substantially as described with reference to the accompanying drawings.

For the Applicants, FRANK B DEHN & CO, Chartered Patent Agents, Imperial House, 15-19 Kingsway, London, W C 2.

Abingdon: Printed for Her Majesty's Stationery Office, by Burgess & Son (Abingdon), Ltd -1964.

Published at The Patent Office, 25 Southampton Buildings, London, W C 2, from which copies may be obtained.

971,357

Description

PATENT SPECIFICATION

DRAWINGS ATTACHED.

971,357 Date of Application and filing Complete Specification:

/ March 4, 1963 No 8536/63.

1 a t l A pplication made in United States of America (No 257,608) on Feb 11, 1963.

Complete Specification Published: Sept 30, 1964.

) Crown Copyright 1964.

Index at Acceptance:-A 4 F 29.

International Classification:-A 47 1.

COMPLETE SPECIFICATION.

Dishwashing Machine and Operational Cycle Therefor.

We, LING-TEMCO-VOUGHT, INC, a Corporation duly organized and existing under the laws of the State of Delaware, United States of America, of P O Box 5003, Dallas 22, State of Texas, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to apparatus for washing articles, and more particularly to improvements in automatic dishwashers and the operational cycle therefor.

To efficiently wash dishes and silverware in an automatic dishwasher, it has been found the washing is facilitated by subjecting such articles to a pre-wash of water having a temperature of about 105 degrees F., and then to subject the articles to a main wash period wherein the water is about 140 degrees F, and then to subject the articles to a water rinse and thereafter to apply steam to said articles to form a distilled water rinse and also heat the articles to facilitate drying on completion of the steaming cycle The dishwasher is connected to a source of water supply which may be a cold water system or from a domestic hot water system With a domestic hot water system as the supply, the temperature of the water may vary over a wide range and be insufficient for proper washing of the articles in the dishwasher In order to provide suitable temperatures to the water for the various cycles of the dishwasher, the present invention contemplates the use of a water heater tank or receptacle located within the dishwasher cabinet with such tank being of small size both for space requirements and to avoid high capacity of the electric heaters in the tank, but still supply water of lPrice 4 s 6 d l desired temperature for each portion of the cycle of operation The invention contem 45 plates the flow of water from the supply through the tank to the washing compartment and the heating of the water as it passes through the tank, and in order to increase the temperature of said water dur 50 ing portions of the cycle, the water flow is interrupted periodically to thereby reduce the average rate of flow through the tank in order that the heater can increase the temperature of the water 55 Thus according to the present invention there is provided an automatic dishwasher, comprizing operating means for effecting a washing operation in a washing compartment supplied with water through a flow 60 conduit provided with a valve, wherein a closed liquid receptacle is interposed in the flow conduit between the valve and the washing compartment and provided with means for heating the contents of the 65 receptacle, timer means being provided for energization of the heating means to heat the water as it passes through the receptacle, and said timer means effecting periodic opening and closing of the valve to reduce 70 the average rate of flow through the receptacle and thereby increase the temperature of water delivered to the washing compartment for a washing cycle.

The principal objects of the present in 75 vention are to provide an improved automatic dishwasher including a casing having a washing compartment in which articles to be washed are supported with a combination of elements in the sequence control 80 whereby a cold water supply may be used and heated to desired temperatures for a prewash, a main wash, a rinse and then a steaming cycle for delivery to the washing compartment during the respective cycles; 85 to provide a new combination of elements in a sequence control of an automatic dishwasher having its own water heater tank in which a timer controls the duration and sequence of each operation and mechanism to periodically interrupt the flow of water through the tank to reduce the average rate of water flow whereby the electric water heaters in the tank heat the water therein to a higher temperature; to provide such a dishwasher with a water level control in the washing compartment and a valve controlled drain for draining all liquid from the washing compartment and control means for shutting off the water flow to the water tank for the heating of water remaining therein into steam which is delivered to the washing compartment for steaming of the articles therein; and to provide improvements in automatic dishwashing and steaming apparatus and the operation of cycling thereof to efficiently wash dishes and the like that is economical to manufacture, easily maintained and that is positive in operation.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings wherein are set forth by way of illustration and example certain embodiments of this invention.

Figure 1 is a perspective view of dishwashing apparatus embodying the features of the present invention, with portions broken away to better illustrate the component parts.

Figure 2 is a transverse sectional view through the dishwashing apparatus taken on the line 2-2, Figure 1.

Figure 3 is a sectional view through a float valve for preventing excessive water level in the washing compartment.

Figure 4 is an elevational view of a timer cam for effecting opening and closing of a fill valve in the water supply.

Figure 5 is a wiring diagram of an automatic dishwasher with the essential operating parts diagrammatically shown.

Referring more in detail to the drawings:

1 generally designates an automatic dishwasher which includes a casing 2 having a portion defining a washing compartment 4.

The compartment portion of the casing has a bottom wall 5, rear wall 6, top wall 7 and end walls 8 and 9 to form a water-tight compartment having an access opening 10 normally closed by a door 11 The bottom wall extends forwardly and downwardly from the lower portion of the rear wall and then forwardly and upwardly terminating in an upstanding flange or wall portion 12 The bottom portion also has a recessed portion 13 substantially on a level with the lowermost portion of the bottom wall to which is connected a drain mechanism 14 The bottom wall 5 forms a sump 15 that extends longitudinally for the length of the washing compartment, and positioned in said sump and extending longitudinally of the washing compartment is a distributor 16 to move water or washing liquid from the sump 70 and distribute it at relatively high velocity streams or sprays on articles 17 suitably supported on racks 18 or the like arranged in the washing compartment above said distributor 75 The drain mechanism 14 communicates the washing compartment at the sump thereof with a suitable disposal, for example, a sewer or the like, by either gravity flow or by a pump (not shown) The drain 80 mechanism 14 includes an end portion 19 adapted to be connected to a disposal line and also has two conduits 20 and 21 which lead to the washing compartment The conduit 20 extends through the bottom wall 85 and terminates in an open end 22 adjacent said bottom wall for substantially complete draining of liquid therefrom, said draining being controlled by a valve 23 preferably actuated by a suitable motor 24 such as 90 solenoid or the like The conduit 21 extends through the bottom wall and upwardly therefrom and has an open end 25 defining an overflow pipe of suitable height for the maximum desired level of washing 95 liquid in the washing compartment, the open end of the drain pipe or conduit 21 being at a level below the lower edge of the door opening 10 The conduit 21 connects with the drain end portion 19 downstream 100 of the valve 23 for unrestricted flow to the disposal.

The door 11 is preferably hingedly mounted at its lower edge as by hinged members 26 for outward swinging move 105 ment with the edges of the door and the portion of the casing defining the door opening having suitable resilient seal members 27 to provide a substantially watertight seal.

However, the lower portion of the door ex 110 tends downwardly and terminates in a flange 28 inwardly of the flange 12 on the bottom wall 5 to form a vent opening 29 having a resilient cellular material 30 disposed therein to form a closure as to suds 115 and the like but permit passage of air therethrough.

The casing 2 has an extension beyond the end wall 8 of the washing compartment, said extension having an end wall 31 which 120 co-operates with -said wall 8 and a front wall 32, rear wall 33 and bottom 34 to define a chamber 35 Located in the chamber 35 is a float structure 36 which includes a housing 37 suitably supported on the end 125 wall 8 with an opening 38 communicating the washing compartment below the maximum level of liquid therein with a float chamber 39 in the housing 37 A float 40 is arranged in the float chamber and has an 130 971,357 trough will run back into the washing compartment The pipes 56 and 58 form a conduit from a water supply to the washing compartment with the receptacle 55 interposed in said flow conduit The tank 55 pre 70 ferably has thermostats 62 and 63 mounted on the respective ends and two heating elements 64 and 65 mounted inside of said tank preferably one above the other in spaced relation, said heating elements being 75 sealed heating units connected into the electric circuit 44 to be energized as later described.

In the illustrated sequence control, a timing motor 66 is arranged in the chamber 35 80 behind the front wall 32 The timing motor 66 through suitable gearing (not shown) actuates a camshaft 67 which has a control knob 68 mounted thereon at the front of the wall 32 The timer motor 66 rotates the 85 shaft 67 on which cams 69, 70, 71, 72 and 73 are carried, said cams actuating switches 74, 75, 76, 77 and 78 respectively, for controlling the cycling operations as later described The electric circuit 44 includes 90 leads 79 and 80 connected to a suitable source of electric current, as for example 220 volts, and said lead 79 is connected to the switch 74 whereby upon the cam 69 moving the switch arm 81 to close the 95 switch 74 a conductor 82 is connected in circuit with the lead 79 The lead 80 is connected to the switch 75 and when the cam actuates the switch arm 83 to close the switch 75, a conductor 84 is electrically con 100 nected to the lead 80 The cams 69 and 70 are preferably arranged whereby the switches 74 and 75 are actuated at the same time to make and break the circuits simultaneously A signal light, for example a neon 105 light 85, has its terminals connected by conductors 86 and 87 respectively to the conductors 82 and 84 to provide a visual signal that the circuit is completed and power is on A switch 88 is arranged in the conductor 110 82 and is positioned adjacent the door 11, said switch being biased whereby it is in circuit-opening position when the door 11 is open and is in circuit-making position only when the door 11 is closed 115 The timer motor 66 is connected in circuit by conductors 89 and 90 connected to the conductors 82 and 84 respectively, the connection with the conductor 82 being relative to the switch 88 whereby the circuit to 120 the timing motor is interrupted if the door 11 and switch 88 are opened The solenoid 24 of the drain valve 23 is connected by a conductor 91 to the conductor 84 and by a conductor 92 through the switch 76 to the 125 conductor 82 whereby the cam 71 operating the switch 76 controls the drain valve 23.

The conductor 82 is connected by a conductor 93 with one terminal of the heating element 64 with the thermostat 62 arranged 130 operative connection to stop the water flow to the chamber which, in the illustrated structure, is an upwardly extending shank 41 extending through the top wall of the a housing that is connected by an arm 42 with a micro switch 43 connected in the electric circuit 44 to interrupt the flow of water to the washing compartment if the water level should become higher than that desired or, in other words, higher than the open upper end 25 of the drain conduit 21.

An electric motor 45 is arranged in the chamber 35 and is operatively connected with an impeller 46 of the distributor 16.

Said impeller is positioned inside of a substantially cylindrical housing 47 having a thin perforated wall with ends terminating to define a longitudinal opening 48 whereby upon rotation of the impeller water is discharged through said opening onto articles in the washing compartment The housing 47 is oscillated by means of a connecting rod 49 having one end pivotally connected to the housing 47 as at 50 and the other end pivotally connected as at 51 with a crank arm 52 fixed on a shaft 53 driven by a geared motor 54, said motor being arranged in the chamber 35 Rotation of the impeller is such that sheets or streams of wash liquid are directed from the housing 47 through the opening 48 and the oscillation of the housing is such that the direction of the stream of water from said housing is changed to traverse the interior of the washing compartment 4 and impinge on dishes or the like in any location of the washing compartment.

A water heating tank or receptacle 55 is mounted in the chamber 35 and, in the illustrated structure, said tank is elongated and horizontally disposed The tank is connected to a source of water, as, for example, a domestic water supply, by a conduit or pipe 56 which communicates with the lower portion of the tank 55 A water solenoid fillvalve 57 is arranged in the water supply pipe for controlling flow therethrough to the tank 55 Steam or water from the tank 55 is delivered through a pipe 58 that communicates with the tank 55 at the upper portion thereof and has a discharge end 59 emptying into a trough-like member 60 that has communication through louvered openings 61 with the upper portion of the washing compartment 4 This arrangement provides a spacing between the discharge end 59 of the pipe 58 and the openings 61 to the washing compartment to provide an air break in the washing compartment water supply whereby no liquid can be siphoned from said washing compartment back into the water-system of the house It is preferred that the bottom of the trough 60 be inclined toward the louvred openings 61 whereby any condensation or liquid collecting in the 971,357 in the conductor 82 between the connection of the conductor 92 leading to the drain valve solenoid and the conductor 93 to the heater element 64 Terminals 94 and 95 of the heater elements 64 and 65 respectively are connected by a conductor 96 to the conductor 84 The float switch 43 is in the conductor 96 and is-normally in closed position, said switch interrupting the circuit only when the water reaches an excessive height in the washing compartment The other terminal 97 of the heating element 65 is connected to a conductor 98 that joins with a conductor 99 that is connected with the motors 45 and 54, said motors being connected by respective conductors 100 and 101 to the conductor 84 to complete the circuit The conductor 98 is also connected to a conductor 102 that leads to a contact 103 of the switch 77 The switch arm 104 of said switch is connected by a conductor 105 to the conductor 82 The switch 77 is a double switch that has a contact 106 connected by a conductor 107 with a mechanism 108 for controlling adding of water softener into the system near the end of the complete cycle The connection of the conductors 98 and 99 also is a connection to a conductor 109 which has a cycling thermostat 63 therein, said conductor being connected as at 110 to a conductor 111 that connects a contact of the switch 78 with a solenoid of the fill valve 57 The other terminal of the solenoid is connected by a conductor 112 to the conductor 96 between the heating elements and the float switch 43.

The switch arm 113 of the switch 78 is connected by a conductor 114 to the conductor 82.

In operation of an apparatus constructed and assembled as described, and with the water pipe 56 connected to a source of water supply, the drain end 19 connected to a disposal, and the leads 79 and 80 connected to a suitable source of electric current, the door 11 is opened and dishes or the like articles to be washed are placed in the washing compartment The door 11 is then closed whereby the switch 88 is in circuitmaking position Then the manual control knob 68 is turned to move the cams to the starting position wherein cams 69 and 70 close the switches 74 and 75 to complete the electrical circuit energizing the signal bulb 85 and the timing motor 66 The cam 71 also preferably closes the switch 76 to complete the circuit through the solenoid drain valve 23 to open the drain and the cam 73 closes the switch 78 to energize the solenoid of the fill valve 57 to open same to start the flow of water through said valve to the tank 55 to fill said tank Since the washing compartment would be empty, the float switch 43 is in circuit-making position and the heater element 64 is energized to heat the water as it moves into the tank 55 and flows therethrough through the pipe 58, trough 60 and louvred openings 61 into the washing compartment After a short interval and continued movement -of the cams 70 on the camshaft 67, the cam 71 causes the switch 76 to open, interrupting the circuit to the drain;alve 23, closing the drain whereby washing liquid will collect in the sump of the washing compartment The 75 cam 72 causes the switch arm 104 to engage the contact 103 so as to energize the heater As an example of water heating the two heating elements 64 and 65, in normal flow of the water through the tank 55, will cause 80 the water to be heated to a temperature by approximately 105 degrees F As this heated water flows into the washing compartment, motors 45 and 54 are energized to actuate the water distributor whereby 85 the water is discharged against the articles in the washing compartment, providing a pre-wash After such a pre-wash, as for example, four minutes, the cam 71 again moves the switch 76 to close the circuit to 90 the drain valve 23, opening same for quick discharge of the water from the sump of the washing compartment The cams 72 and 73 also open the switches 77 and 78 to close the fill valve and stop the motors 45 and 54 95 Then the cams 67, 72 and 73 move the switches 76, 77 and 78 to interrupt the circuit to the drain valve 23 whereby it is closed and open the fill valve and reenergize the motors 45 and 54 and the water 100 again starts to collect in the sump for the main washing cycle.

It is desired to have hotter water for the main washing To achieve this, a pulsing mechanism is built into the timer and cuts 105 the fill valve off and on intermittently during the entire main wash period, as for example, at a rate of 7 seconds on, that is the fill valve delivering water to the tank, and 53 seconds off, that is the fill valve being 110 closed This pulsing action is provided by a portion 115 of the cam 73 which opens and closes switch 78 and circuit to the fill valve 57 so that the fill valve is closed intermittently thereby permitting the two 115 heating elements 64 and 65 in the tank 55 to heat the water therein to a higher temperature When the fill valve 57 is closed, no water is flowing from the tank 55 to the washing compartment 4 Then, when 120 the cam 73 actuates the switch 78 to again complete the circuit to the fill valve 57, water flows to the tank 55 and a corresponding amount of water flows into the washing compartment 4 This intermittent flow with 125 continued heating reduces the average rate of water flow, as for example, to 13 per cent of the normal flow rate, and this lower average flow rate allows the water to reach the desired higher temperature, as for ex 130 971,357 971,357 5 ample 140 degrees F When the main washing cycle is completed, the cams 71, 72 and 73 actuate their respective switches 76, 77 and 78 to interrupt the circuit to the fill valve 57, motors 45 and 54 and heater 65 and actuates the drain valve 23 for fast draining of the water from the washing compartment After a short interval, as for example one minute, to permit such draining, the cams 71, 72 and 73 again actuate the motors 45 and 54 and open the fill valve 57.

This, provides for rinse water to run through the tank 55 and be heated, and this water is delivered to the washing compartment for rinsing of the dishes It is preferred that the cams 71, 72 and 73 be arranged whereby the rinse water is drained and the motor stopped and the fill valve closed for the draining of the rinse water from the washing compartment, and then close the drain valve and again supply water by opening the fill valve and energizing the motors 45 and 54 to provide another rinse.

As many rinses as is desired can be provided; however, it is preferred that there be three rinses At the end of the final water rinse cycle, the cams 71, 72 and 73 again actuate their respective switches whereby the solenoid 24 of the drain valve 23 is energized to open the drain for draining off the water from the washing compartment The circuits to the motors 45 and 54 are interrupted to stop the water distributor 16 in the washing compartment and the circuit to the fill valve 57 is interrupted to stop flow of water to the tank 55 However, the circuit is still completed to the timing motor and to the heating element 64 which heats the water in the tank 55 generating steam which steam is delivered by the pipe 58 to the washing compartment to steam the dishes or articles therein The steam 'entering the washing compartment will condense on the articles, creating a distilled water rinse of said articles The buildup of steam condensate causes the articles to drip, thus displacing droplets previously left on the articles These droplets normally contain minerals that would leave water spots when the articles dry so that the distilled water rinse removing such droplets eliminates the spots that otherwise would be on the dishes The steam also heats the dishes so as to facilitate their drying.

If the temperature of the tank 55 should become excessive, as for example if the water in the tank should all be evaporated prior to the end of the complete cycle, in other words before the timing motor moved the cams 69 and 70 to a position to interrupt the circuit, the safety thermostat 62 would interrupt the circuit to the heater 64 and thereby prevent damage to the heating element or tank If the water in the tank 55 during the pulsating heating period reaches a temperature over a predetermined maximum, the cycling thermostat 63 would override the pulsing contact of the timer and open the fill valve 57 for continuous flow of water through the tank 55 until the 70 proper temperature is re-established This thermostat, however, is ineffective during the steaming cycle because during that period the cam 73 has caused the switch 78 to open, interrupting the circuit to the fill valve 57 75 If the drain pipe 21 should become clogged and water in the washing compartment should reach an excessive level, the float switch 43 opens the circuit to the fill valve 57 and also to both of the heating elements 64 80 and 65 so as to stop the inflow of water until the water recedes to the desired level, and when the proper water level is established the float switch will re-establish the fill valve circuit 85 When the complete steaming cycle is over, the timing motor 66 will have moved to position the cams 69 and 70 wherein they open the switches 74 and 75, interrupting the circuit to the leads 79 and 80 respec 90 tively, thereby shutting off the entire machine until such time as the manual control 68 is again rotated to start the operation.

It is believed obvious that there has been 95 provided an automatic dishwashing machine that will suitably heat the water and generate steam with controls for efficiently washing, rinsing and steaming dishes in controlled cycles with drain operations for rapidly 1 00 carrying away the water whereby any food particles will be carried therewith.