US3072128A

US3072128A - Continuous flow dishwasher and steamer

Info

Publication number: US3072128A
Application number: US85558A
Authority: US
Inventors: Duane A James
Original assignee: Ling Temco Vought Inc
Current assignee: Ling Temco Vought Inc
Priority date: 1961-01-30
Filing date: 1961-01-30
Publication date: 1963-01-08
Anticipated expiration: 1980-01-08
Also published as: BE610348A; CH398905A; NL271783A; GB976577A; ES272279A1

Description

Jan. 8, 1963 D. A. JAMES 3,072,

CONTINUOUS FLOW DISHWASHER AND STEAMER Filed Jan. 30, 1961 4 Sheets-Sheet 1 mmvron DUANE- A. JAMEC ilimw/w' ATTORNEYS I Ja,n. '8, 1963 D- A. JAMES commuous FLOW DISHWASHER AND STEAMER 4 Sheets-Sheet 2 Filed Jan. 30. 1961 IN VEN TOR.

DUANE A. JAMES A TTORNEVS Jan. 8, 1963 D. A. JAMES 3,072,128

CONTINUOUS FLOW DISHWASHER AND STEAMER Filed Jan. 30, 1961 4 Sheets-Sheet 3 T m L 1 N m w m m o m w m o 5\ 3 3, g t "i Y 19 m N I w I '1 L a Ill 1 l I C o I w I I 1 E] i (I;

w {R m 3 1 INVENTOIL DUANE A. JAMES M MW 4 Sheets-Sheet 4 Jan. 8, 1963 D. A. JAMES CONTINUOUS FLOW DISHWASHER AND STEAMER Filed Jan. 50; 1961 um Q 0 0 mm ms R w K g m United States Patent M 3,072,128 CONTINUOUS FLOW DISHWASHER AND STEAMER Duane A. James, Richardson, Tex., assignor, by mesne assignments, to Ling-Temco-Vought, Inc., Dallas, Tex., a corporation of Delaware Filed Jan. 30, 1961, Ser. No. 85,558

Claims. (Cl. 134--57) This invention relates to apparatus for washing articles, and more particularly to apparatus for washing dishes and the like and applying steam thereto.

The principal objects of the present invention are to provide improved apparatus of this class including a casing having a washing compartment in which articles to be washed are supported and washing liquid directed thereon in a washing operation where-in water is delivered to the washing compartment for a predetermined period and is then drained therefrom and steam is then generated and delivered to the compartment whereby the steam condenses on the articles forming a distilled water rinse and heats the dishes for rapid air drying on completion of the steaming cycle; to provide such a structure including a steam generating apparatus through which water flows to the washing compartment with the steam generating apparatus having a receptacle with walls of a different thermal expansion and contraction than scale from the water whereby when all of the water in the receptacle is generated into steam and the receptacle is cooled any scale deposit will crack and separate from the walls of the receptacle and flow to the washing compartment with the flow of water on initiation of the next washing cycle; to provide such an apparatus wherein the flow from a hot water supply is continuous for the washing cycle and the washing compartment has a drain with a small drain aperture at the bottom providing a rate of draining less than the input flow and a large drain aperture at a maximum liquid level to maintain the liquid level in the Washing compartment during the washing operation and provide for draining of all liquid from the washing compartment during the generation of steam in the steam generating apparatus; to provide such an apparatus with an air space between aligned flow portions of the duct from the steaming apparatus to the washing compartment and vent openings between portions of the casing whereby flow of liquid or steam to the washing compartment effects circulation of air and steam in the washing compartment; to provide such a structure with electrical devices operating automatically in a predetermined sequence to successfully complete the required operations; to provide a switch mechanism responsive to expansion and contraction of the steam generating receptacle to prevent overheating; and to. provide improvements in dishwashing and steaming apparatus with sim plifierl construction and reduced cost of manufacture and yet retain positive and efiicient operation.

' Other objects andadvantages 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. FIG. 1 is a perspective view of dishwashing apparatus embodying the features of the present invention with portions broken awayv to thereof.

better illustrate the structure FIG. 2 is a vertical sectional View through the dishwashing apparatus taken on the line 22, FIG. 1.

FIG. 3-is a partial horizontal sectional view through the dishwashing apparatus taken on the line 3-3, FIG..2.

FIG. 4 is a fragmentary horizontal sectional view through the dishwashing apparatus taken on the line 4-4,

. FIG. 2.

FIG. 5 is a diagrammatic view illustrating the electrical circuits and devices in the apparatus.

FIG. 6 is an enlarged longitudinal sectional view through the steam generating apparatus.

FIG. 7 is a bottom view of the steam generating apparatus and heater switch in circuit-making position with portions of the receptacle broken away to show the heater therein.

FIG. 8 is a bottom view of the steam generating apparatus with the heater switch in circuit-interrupting position.

Referring more in detail to the drawings:

1 designates apparatus for washing articles such as dishes and the like and consists of a casing 2 having a receptacle 3 defining a washing compartment 4-. The receptacle portion of the casing has end walls 5 and 6 connected by a bottom wall 7, rear wall 8 and top wall 9 to form a watertight tank having an access opening 10 normally closed by a door ll. The bottom wall 7 extends forwardly and downwardly from the lower portion 12 of the rear wall 8 to a line 13 and then forwardly and slightly upwardly to a line 14 from which the upward inclination is increased to the forward portion of the casing where said bottom terminates in an upstanding wall portion 15 having an inturned flange 16 on its upper edge defining the lower edge of the opening 10. This arrangement of the bottom forms a sump 17 in the lower portion of said bottom. A drain pipe 18 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 pipe extends upwardly into the bottom wall and has an open upper end 19 defining an overflow pipe of suitable height for the maximum desired level of washing liquid in the washing compartment, the open end 19 of the drain .pipe being at a level below the lower edge of the door opening 10. The drain pipe 18 also has a low flow rate opening or orifice 20 providing restricted flow from the washing compartment, said orifice being in the drain pipe and communicating with the sump portion of the washing compartment at the lowest point for sub.- stantially complete draining of washing liquid from thewashing compartment, the orifice20 being of such size that flow therethrough is restricted to a rate substantially lower than the input flow rate of water or washing liquid to the washing compartment whereby continuous flow through the orifice during introduction of. washing liquid. will allow the washing liquid to accumulate to a level defined by the open end 19 of the drain, and thereafterduring washing operations water introduction is continued and also is drained at the same rate through both the orifice 20 and the open upper end of the drain pipe.

The sump 17 extends longitudinally of the washing compartment or between the end walls 5 and 6, and a and the like to be washed, said articles or dishes being;

supported on suitable racks 2.3 movably supported in guide tracks 24 carried by the 'end walls 5 and 6, the racks supporting the articles above the distributor 21. The guide tracks 24 are preferably arranged whereby the racks 23 may be pulled outwardly of the washing com partment through the opening 10,, v

The door 11 has end walls 25,-top w tom wall 27 connected to form a frame with the forward edges terminating in inturned flanges 28 against which a forward wall 29 is removably held, said forward wall preferably being transparent material such asglass orthe like to provide a view into the washing compartment. The glass wall 29 is held in place by spring members 30 i all 26 and a botthe housing 60* having portions 31 engaging the inner side edges of the glass wall and end portions 32 engaging reinforcing members 33 spaced from the glass wall and preferably mounted on the end walls of the door. The door 11 is preferably hingedly mounted at its lower edge for outward swinging movement which is limited whereby the door will swing only to approximately a horizontal position. The swinging movement of the door is limited by a rod member 34 hingedly mounted as at 35 on the door and slidable in an opening 36 in a bracket 37 at one end of the washing cornpartment, said rod having a stop member 38 on the end thereof adapted to engage the bracket when the door is in horizontal position. The edges of the top and end walls of the door adjacent the casing extend into channel portions 39 at the top and sides of the door opening and engage resilient seal members 40 in said channels to make a substantially watertight seal at the sides and top of the door opening when the door is in closed position. The bottom wall 27 of the door slopes downwardly and inwardly relative to the door opening and has a portion 41 extending through the opening and terminating in an angle-shaped portion 42 having a seal member 43 adapted to engage a flange 44 of a resilient sheet 45 when the door is in closed position, said seal portion 43 and the angle member 42 being spaced from the flange 16 when the door is in closed position to provide a vent opening 46. The fiat resilient sheet 45 is secured to the bottom wall with a space 47 therebetween to form a vent passage, said sheet extending upwardly and forwardly to resiliently engage the angle portion 42 of the door when the door is in closed position, as illustrated in FIG. 2. When water is at washing level the water closes the vent passage whereby when the water is drained from the washing compartment the vent is opened and vapors can pass therethrough.

The end walls 5 and 6 extend below the bottom wall 7 and have a lower edge 47' adapted to rest on a suitable support. The space below the bottom wall 7 is closed at its forward portion by a forward wall 48. The casing 2 has an extension 49 beyond the end wall 5 of the receptacle, said extension 49 having an end wall 50 spaced from the end wall 5 and connected to a rear wall 51 which connects with the rear wall 8. The top wall 9 extends over the extension and is connected to the end Wall 50.

The extension has a forward wall 52 between the end wall 50 and the door opening 10 on which a timer and control switch 53 is mounted. In the chamber 54 defined by the extension an electric motor 55 is suitably mounted and operatively connected with the impeller shaft 57 of the distributor 21 which is inserted into and keyed to hollow motor shaft 56. The impeller shaft 57 has substantially oppositely extending vanes 58 with outer end portions 59 angled in the direction of rotation of the impeller. A housing 60 surrounds the impeller and is mounted for rotative movement coaxially thereof. The housing 60 has end members '61 connected by wall members 62 to define a cylindrical housing with the wall members 62 spaced to define an inlet opening 63 and a discharge opening 64, the inlet opening 63 preferably being covered by a fine screen 65 to prevent passage of food and other particles into the interior of the housing 60. The housing 60 is oscillated by means of a connecting rod 66 having one end pivotally connected as at 67 with in spaced relation to the axis thereof and with the other end of the connecting rod pivotally con nected as at 68 with a crank member 69 fixed on a shaft 70 which extends through the end wall 5 to a small motor 7-1. Operation of the motor 71 rotates the shaft 70 and crank 69 to oscillate the housing 60 whereby rotation of the impeller and oscillation of the housing causes wash liquid tov be drawn through the screen 65 into the interior of thehousing and the impeller drives said wash liquid through the opening 64 with substantial velocity. Rota- 'tion of the impeller is such that the sheet or streams of wash liquid are directed from the housing 60 substan tially tangentially of the portion 72 of the housing and 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 adapted to have articles to be washed therein.

A steam generator structure 73 is mounted in the chamber 54 and is preferably connected to a source of hot water, as, for example, the usual hot water system of a house, said connection being by a pipe 74 communicating with the steam generator, with a valve 75 in the pipe 74 for controlling flow therethrough. Steam or water from the steam generator 73 is delivered through a pipe 76 which has its discharge end 77 aligned with and spaced from an inlet 78 of a duct 79 communicating with the interior of the washing compartment to provide an air brake in the washing compartment supply whereby no liquid can be siphoned from said washing compartment back into the water system of the house. A partition 80 is arranged in the chamber 54 between the

walls

5 and 50 and extending from the forward wall 52 to an upright wall 81 to cooperate with the top wall in defining an air circulation or vent chamber 82 which has communication with the exterior of the casing through vent openings 83 in the upper portion of the forward panel 52 and with the interior of the washing compartment through an opening 84. A deflector plate 85 extends partially over the opening 84 at an angle to the wall 5 to retard entry of washing liquid into the vent chamber 82. It is preferable that the partition 80 be inclined toward the opening 84 whereby any condensation or liquid collecting in the vent chamber will run back into the washing compartment.

The steam generator 73 is preferably in the form of an elongated tank with end walls or

members

86 and 87 connected by a shell 88 formed of metal having a high coefficient of expansion such as aluminum and the like and of diiferent thermal expansion that scale that is deposited from evaporating water. In the structure illustrated, the shell 88 is in the form of a cylindrical tube with the ends of the wall 89' thereof turned outwardly to form flanges 98 which are clamped in sealing engagement with suitable gaskets 9d of asbestos or the like which overlies the inner surfaces of the

end walls

86 and 87, the sealing engagement of the flanges 90 with the gaskets 91 and end

walls

86 and 87 being effected by clamp rings 92 engaging the flanges 90 and secured to the

end members

86 and 87 by suitable fastening devices such as screws 93 and nuts 94. The inlet pipe 74 communicates with the interior or chamber 95 of the generator tank and the outlet pipe 76 communicates with said chamber 95 at the upper portion thereof. In the illustrated structure, the tank is arranged with the shell in horizontal relation, and the pipes 74 and 76 communicate with the interior or chamber through the end wall 86, with the pipe 76 communicating in the upper. portion of the chamber.

It is preferred that a vertical baflle 96 be arranged in the chamber 95 preferably spaced in the upper portion and extending downwardly therefrom, said bafi-le being used to press heater element 97- against the chamber 95 to facilitate rapid heat transfer to chamber. A zinc anode or the like is placed in chamber 95 to reduce corrosion or galvanic action in the metals forming the steam generator.

An immersion type heating element 97 is arranged in the chamber 95 adjacent the lower portion thereof and, in the illustrated structure, said electrical heating element is arranged in a U-shape with the legs extending through the end wall 86 with terminals for connection into an electnic circuit as later described. The. inner end of the heating element preferably is positioned on a metal- =spacer 98 that rests on the lower portion of the wall 89 to render the tank wall 89 quickly responsive to change of temperature in the interior of the tank and prevent galvanic corrosion. VA switch structure 99 is arranged on the steam generator and is responsive to a predetermined thermal expansion or extension of the length of the tank a to control the supply of electric current to the heating element, the

electrical contacts

100 and 101 of the switch 99 being arranged to be in circuit-making position when I the temperature in the steam generator is at or below a desired steam-generating temperautre as, for example, below 215 F., and said contacts separated or in circuitbreaking position when the temperature rises above a predetermined maximum as when all of the water in the chamber 95 is evaporated therefrom. In the structure illustrated, the switch 99 has laterally spaced fiat

resilient members

102 and 3 wi-th their ends connected to

blocks

104 and 105 arranged whereby the

spring members

102 and 103 are biased toward each other. The block 105 is secured by a suitable fastening device 106 to a bracket 107 fixed to the end member 87 as by one of the clamp ing screws '93. The block 104 is slidably mounted on a shank 108 which is preferably threaded and provided with adjusting nuts 109, said shank 108 being fixed relative to the end plate 86 whereby the adjusting nuts 109 may move the block 104 relative thereto. Movement of the block 104 toward the end plate 86 tends to apply tension to the

spring members

102 and 103 and separate the

contacts

100 and 101, this adjustment being arranged whereby a predetermined expansion or extension of the Wall 89 of the steam generator effecting greater spacing of the

end members

86 and 87 will separate the

contacts

100 and 101 and thereby interrupt the circuit to the heating element 97 and, on cooling of the steam generator, the wall 89 will contract whereby the

spring members

102 and 103 will again move the

contacts

100 and 101 into circuit-making position.

In the electric circuit, as illustrated in FIG. 5, leads 110 and 111 are connected to a suitable source of electrical energy as to an outlet of a house circuit. The timer assembly 53 preferably is arranged whereby a main switch 112' in the lead 110 is closed during the entire time interval of desired operation of any of the apparatus. A second switch 113 is of a two-position type to provide a washing rinsing cycle and a steaming cycle. A suitable timer has cams 114 and 115 to operate the

switches

112 and 113 respectively whereby when the timer knob is operated to ettect operation of the washing machine the switch 112 is in circuit-making position and switch him 113 is moved to engage a contact 116 to a conductor 117. A switch 118 is located in the conductor 117, said switch being actuated by the door 11 whereby the switch is in circuit-making position when the door is closed and is moved to circuit-interrupting position when the door is moved toward open position. The switch 118 closes the circuit through a conductor 119 to a solenoid valve 75 in the feed line 74 whereby when the solenoid is energized the valve is opened, the circuit being completed from the solenoid valve 75 through a conductor 120 to the lead 111. The switch 118 also connects the circuit through a conductor 121 to a motor control 122 which is in turn connected to conductors 123' and 124 to motors 71 and 55 respectively which are in parallel circuit, the motors being connected through

conductors

125 and 126 respectively to the lead 110. The drain from the drain pipe 18 may be of a gravity fiow typeor may be supplied with a pump and, in the circuit of FIG. 5, a pump motor 127 is connected by a conductor 128 to the circuit between the

switches

112 and 113 with the other side of the pump driving motor connected by a conductor 129 to the lead 111 whereby the pump motor 127 will operate throughout the cycle of the washing and steaming'operations. 'At the end of the predetermined washing time, the timer switch 53 moves the switch arm 113 into engagement with a contact 130 interrupting the circuit to the solenoid valve 75 and motors 7'1 and 55 thereby shutting off flow of water from the feed line 74 and stopping the impeller or distributor in the washing compartment. The circuit is then completed through a conductor 132, the heating element 97 and then through the

contacts

100 and 101 of the switch 99, and a conductor 133 to the lead 111, the timer being set for a duration of operation whereby the heating element is energized for a period sufiicient to generate most of the water in the steam generator into steam for delivery to the washing compartment. If the generation of the water into steam is complete, the switch 99 will interrupt the flow of current to the heating element 97 periodically to prevent overheating of same until the time interval established by the timing switch 53 has elapsed, at which time the timer moves the switcharm 112 to interrupt the circuit to the pump and to the heating element.

In the operation of a dishwashing apparatus constructed and assembled as described, the door 11 is opened, and the racks 23 pulled outwardly on the door and loaded with articles to be washed. A suitable quantity of detergent is then placed in the dishwashing compartment as by sprinkling on the bottom wall '7. The rack 23 loaded with the articles is then moved into the dishwashing compartment and the door 11 moved to closed position. Timer knob 53 is then moved to the required time interval, thereby effecting closing of the switch 112 and moving the switch arm 113 into engagement with the contact 116 energizing the motors 55 and 71 to operate the distributor mechanism, and also energizing the solenoid valve 75 to open same for flow of hot Water through the pipe 74 to the steam generator. The hot water will flow into the chamber of the steam generator, filling same and then the water will flow under pressure through the pipe 76 and be discharged into the inlet 78 of the duct 79 for delivery into the washing compartment. While a small quantity of the water will escape through the orifice 20 to the drain, the water level will gradually increase in the washing compartment and, as it reaches a height whereby it is engaged by the impeller of the distributor, the water will be directed in streams against the articles in the racks, the streams traversing the washing compartment. The flow of water into the Washing compartment will continue and, after it reaches a level of the overflow opening 19, the level will be maintained constant with the water being discharged through the drain at the same rate as the input into the washing compartment. This hot water flows through the steam generator continuously, but preferably the heating element 97 is not energized during the washing cycle. The detergent mixes with the water in the washing compartment and, since there is continuous fiow during the washing cycle, the washing liquid consisting of the water and detergent thrown against the dishes with substantial force by the distributor 2-1 will eiiect a washing action removing particles of food and the like from the articles. it has been found that a regulated flow of approximately three quarts of water per minute being delivered to the washing compartment provides a suitable rate when the sump 17 is sized to accumulate approximately one gallon of water when the overflow level is reached. It has also been found that approximately seven gallons of Water introduced into the washing chamber provides sufficient rinsing using water from the Water supply. Such Water change occurs automatically without varying the timer cams, electrical circuit or use of mechanical devices. Water change occurs by displacing water containing detergent and soil down the drain with incoming water. This is accomplished with out stopping the impeller of the distributor or reducing the flow of washing or rinsing action from this device. It has been further found that a steam generator with a capacity of approximately three pints is very satisfactory for ordinary dishwashing and steaming apparatus,

When the washing-rinsing cycle has been continued for a predetermined period of time and, preferably, in a period in which approximately seven gallons of water is delivered to the steamer in the flow to the washing compartment, the articles will have been washed and rinsed, and the timer will then indicate completion of the cycle by moving the switch arm 113 into engagement with the 7 contact 130, interrupting the circuit to the valve 75 and motors 71 and 55, stopping flow of Water through the steam generator to the washing compartment and stopping operation of the Wash liquid distributor. The heating element 97 is then energized to heat the water which accumulated and remains in the chamber to generate steam therefrom. As long as water remains in the chamber 95, the elongation of the wall $9 will be insuilicient to effect sufi'icient movement of the switch 99 to separate the contacts ltlil and ltll. As the steam is generated, it,

is discharged through the pipe 76 and into the duct 79 for flow into the washing compartment. When the steam reaches the articles, it will be condensed onto 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 containing minerals that would leave water spots when the articles dry. Also, the steam flow into the inlet 78 of the duct 79 induces fiow of air from the vent chamber 83 so that steam moving through the opening 84- will be drawn back into the washing compartment through the duct '79 by the inducement of the steam flow into the duct. If all of the water is converted into steam in the steam generator, the heat from the heating element 97 will not be dissipated through water and there-- by will increase the temperature in the chamber 95, but that increase in temperature will be quickly sensed through the pad 98 by the wall 89 effecting further expansion of same whereby the elongation of the wall 89 will actuate the switch 99 to separate the contacts rea and ltlll interrupting the circuit to the heating element 97 to prevent overheating of same. While the circuit to the heating element is interrupted, the steam generator wall $9 will tend to cool and contract whereby the switch 99 will be actuated to engage the contacts 1% and lltll and again restore the circuit to the heating element 97. This making and interrupting of the circuit to the heating element will continue until the timing switch completes the cycle period of operation at which time the switch is moved to interrupt the circuit and stop operation.

During the conversion of the water in the chamber 95 of the steam generator to steam, there will be some scale deposited on the walls of the generator, this scale being the mineral removed from the steam condensate; however, the scale so deposited has a different coeiiicient of expansion than the metal of the wall 89. Therefore, upon completion of the washing and steaming cycle, the contraction of the wall 89 being different than that of the scale will cause the scale to crack and tend to separate in small particles from the interior surface of the wall Then, upon the next washing operation, the initial water flowing through the chamber 95 of the steam generator, on its way to the washing compartment, will tend to carry the fine particles of scale therewith, thereby providing a selfcleaning operation which tends to maintain the steam generator free of scale. After completion of a steaming operation, the articles will be hot and then opening of the door 11 will allow air to enter and steam to escape, providing a very rapid or flash drying of the articles. However, the door may be allowed to remain closed and most all of the water being drained from the washing compartment will provide an air inlet vent under the door whereby the dishes will dry and be ready for use when removed from the washing compartment. The air inlet at low level allows outside cooler air to enter and displace the moist hot air through the upper vent chamber It is believed obvious that lhave provided a dish-washing apparatus and steamer for elliciently washing and rinsing dishes and the like, obtaining any desired number of water changes which occur simultaneously during the application of forceful streams of recirculated liquid to the articles to be cleaned, and generating and applying steam thereto to effect additional rinsing with distilled water and rapid drying free of water spots and the like, and means for disposing of minerals obtained from production of distilled water.

It is to be understood that while I have illustrated and described one form of my invention, it is not to be limited to the specific form or arrangement of parts herein described and shown except insofar as such limitations are included in the claims.

What I claim and desire to secure by Letters Patent is:

1. A steam generating apparatus comprising, an elongate receptacle having spaced ends connected by side walls defining a chamber, said side walls being of metal having substantial expansion and contraction in response to increase and decrease in temperature, a liquid supply communicating with the chamber, a discharge duct communicating with the chamber adjacent the upper portion thereof, means in the liquid supply operative for permitting flow of liquid to the chamber for a predetermined period whereby liquid fills said chamber and then is discharged through the discharge duct, an electric heater device in said chamber for generating steam from liquid therein, said electric heater being positioned adjacent the side walls of the receptacle, and means selectively energizing said electric heater, said steam generating apparatus being characterized by the expansion and contraction between heating and cooling of said side walls being greater than the expansion and contraction of any scale deposited from generating of steam whereby upon generating steam from liquid remaining in the chamber after flow of liquid thereto has stopped and the receptacle allowed to cool any scale on the side walls will crack from said side walls and be carried with liquid flowed through the chamber and discharge duct in the next sequence of operation.

2. A steam generating apparatus comprising, an elongate receptacle having spaced ends connected by side walls defining a chamber, said side walls being of metal having substantial expansion and contraction in response. to increase and decrease in temperature, a liquid supply communicating with the chamber, a discharge duct communicating with the chamber adjacent the upper portion thereof, means in the liquid supply operative for permitting flow of liquid to the chamber for a predetermined period whereby liquid fills said chamber and then is discharged through the discharge duct and the chamber contains a quantity of liquid on stopping of the liquid supply, an electric heater device in said chamber for generating steam from liquid therein, said electric heater being positioned adjacent the side walls or" the receptacle, means forming an energizing circuit including the electric heater, a switch in said energizing circuit including normally engaging contacts, and means supporting said contacts for relative movement and responsive to a predetermined expansion of said receptacle side walls to separate said contacts and interrupt said energizing circuit, said steam generating apparatus being characterized by the expansion and contraction between heating and cooling of said side walls being greater than the expansion and contraction of any scale deposited from generating of steam whereby upon generating steam from liquid remaining in the chamber after flow of liquid thereto has stopped and the receptacle allowed to cool any scale on the side walls will crack from said side walls and be carried with liquid flowed through the chamber and discharge duct in the next sequence of operation.

3. In a steam generating apparatus comprising, a closed receptacle having walls extending longitudinally thereof defining a tubular structure and closed ends forming a closed chamber therein, said longitudinal walls being of metal having substantial expansion and contraction in response to increase and decrease in temperature, a liquid supply line communicating with the chamber fordelivery of liquid thereto, a discharge duct communicating with the chamber adjacent the upper portion thereof whereby liquid from the liquid supply line after filling the chamber will ilow from the discharge duct, control means including a valve in said liquid supply line for. permitting flow of liquid through the chamber for a predetermined period and then stopping flow whereby the chamber is full of liquid, an electric heater having portions in the chamber adjacent the longitudinal wall, means forming an energizing circuit including the electric heater to generate steam from the liquid remaining in said chamber for discharge through a discharge duct, and a switch in said energizing circuit and responsive to a predetermined thermal expansion of the longitudinal wall to interrupt said energizing circuit, said longitudinal wall of the receptacle being characterized by having a thermal expansion and contraction different from the thermal expansion and contraction of scale deposited thereon in generating steam from liquid remaining in the receptacle chamber whereby upon cooling and contraction of said longitudinal wall the scale cracks therefrom and is carried with liquid from the receptacle chamber in the flow of liquid through the chamber on the next sequence of operations.

4. In a dishwashing machine, a casing defining a washing compartment having a bottom, means for holding articles to be washed in said compartment in spaced relation to said bottom, a drain fitting in said bottom having a large opening at maximum liquid level and a restricted opening adjacent said bottom, hot water supplymeans communicating with said compartment for conveying liquid thereto at a rate greater than the drain flow through said restricted opening and lesser than drain flow through said large opening, means directing liquid from adjacent the bottom of said compartment against articles therein for a predetermined period, a closed receptacle in the hot water supply means between a source and the compartment with the connection to the compartment being at the upper portion of said receptacle whereby liquid flow to the compartment is through the receptacle and fills same, control means including a valve upstream from the receptacle and operable for flow of liquid to the compartment for a predetermined period of dishwashing cycle and stopping fiow at the end thereof, and a heating means in the receptacle and operable at the end of the predetermined period of washing cycle to heat the liquid remaining in the receptacle at the end of said predetermined period of washing cycle to convert said liquid to steam for delivery to the washing compartment to steam the articles in said compartment.

5. In a dishwashing machine, a casing defining a washing compartment having a bottom, means for holding articles to be washed in said compartment in spaced relation to said bottom, a drain fitting in said bottom having a large opening at maximum liquid level and a restricted opening adjacent said bottom, hot water supply means communicating with said compartment for conveying liquid thereto at a rate greater than the drain flow through said restricted opening and lesser than drain flow through .said large opening, means directing liquid from adjacent the bottom of said compartment against articles therein for a predetermined period, a closed receptacle in the hot water supply means between a source and the compartment with the connection to the compartment being at the upper portion of said receptacle whereby liquid flow to the compartment is through the receptacle and fills same, control means including a valve upstream from the receptacle and operable for flow of liquid to the compartment for a predetermined period of dishwashing cycle and stopping flow at the end thereof, a heating means in'the receptacle and operable at the end of the predetermined period of washing cycle to heat liquid remaining in the receptacle at the end of said predetermined period of washing cycle to convert said liquid to steam for delivery to the washing compartment to steam the articles in said compartment, and means responsive to a predetermined rise of temperature in the receptacle above the boiling point of said liquid for interrupting heating thereof.

6. In a dishwashing machine, a casing having a washing compartment therein adapted to contain articles to be washed, a closed receptacle, a flow line for delivery of hot water under pressure to said receptacle, a duct having one end communicating with the interior of said washing compartment and the other end open exteriorly of said compartment, a second flow line communicating with the receptacle adjacent the upper portion thereof and having a discharge end aligned with and spaced from the open end of said duct whereby flow from said second flow line is directed into said duct for delivery to said washing compartment, an electric heating device in said receptacle for heating water therein and generating steam, control means including a valve in said first-named flow line for permitting fiow of hot water through the receptacle and to the washing compartment for a predetermined period and stopping fiow at the end thereof, an impeller in the washing compartment, means for operating said impeller to direct water against articles in said compartment to wash said articles, and means forming an energizing circuit in cluding the electric heater and operative to energize the electric heater to generate steam from the water remaining in said receptacle at the end of said predetermined period for delivery of said steam after completion of a washing cycle to said washing compartment where said steam condenses on articles therein and provides a distilled water rinse.

7. In a dishwashing machine, a casing having a washing compartment therein, a closed receptacle, a flow line for delivery of hot water under pressure to said receptacle, a duct having one end communicating with the interior of said washing compartment and the other end open exteriorly of said compartment, a second flow line communicating with the receptacle adjacent the upper portion thereof and having a discharge end aligned with and spaced from the open end of said duct whereby flow from said second flow line is directed into said duct for delivery to said washing compartment, an electric heating device in said receptacle for heating water therein and generating steam, control means including a valve in said hot water fiow line upstream from said receptacle for permitting flow of hot water through the receptacle and to the washing compartment for a predetermined period and then stopping flow at the end thereof, an impeller in the washing compartment, an electric motor for operating said impeller to direct water against articles in said compartment to wash said articles, means forming an energizing circuit including said motor and the electric heater and operative in a sequence whereby the electric motor is operated to drive the impeller during flow of water to the washing compartment and is then stopped and the electric heater energized to generate steam from the water remaining in said receptacle at the end of saidpredetermined period for delivery of said steam after completion of the washing cycle to said washing compartment, said receptacle being of metal having substantial expansion and contraction in response to increase and decrease in temperature, switch means in the electric circuit to the electric heater including normally engaging contacts, and means supporting said contacts for relative movement and responsive to expansion of said receptacle by a predetermined increase in temperature above the boiling point of water to separate said contacts and interrupt said energizing circuit to the electric heater.

8. In a dishwashing machine, a casing defining a washing compartment having a bottom, means for holding articles to be washed in said compartment in spaced relation to said bottom, a drain fitting in said bottom having a large opening at maximum liquid level and a restricted opening adjacent said bottom, hot water supply means communicating with said compartment for conveying liquid thereto at a rate greater than the drain fiow through said restricted opening and lesser than the drain flow through said large opening, a closed receptacle in the hot water supply means between a source and the compartment with the connection to the compartment being at the upper portion of said receptacle whereby liquid flowing through the compartment flows through the receptacle and fills same, an electric heating device in said receptacle for heating water therein and generating steam, control means including a valve in said hot water supply means upstream from said receptacle for permitting flow of hot water through the receptacle and to the washing compartment for a predetermined period and then stopping flow at the end thereof, an impeller in the washing compartment, an electric motor for operating said impeller to direct water against articles in the compartment to wash said articles, means forming an energizing circuit including said control means and the electric heater and operative in a sequence whereby the electric motor after flow of water to the washing compartment is stopped and the electric heater is energized to generate steam from the water remaining in said receptacle for delivery of said steam after completion of the washing cycle to said washing compartment, said receptacle being of metal having substantial expansion and contraction in response to increase and decrease in temperature, switch means in the electric circuit to the electric heater including normally engaging contacts, and means supporting said contacts for relative movement and responsive to expansion of said receptacle by a predetermined increase in temperature above the boiling point of water to separate said contacts and interrupt said energizing circuit to the electric heater.

9. In a dishwashing machine, a casing defining a washing compartment having a bottom, means for holding articles to be washed in said compartment in spaced relation to said bottom, a drain fitting in said bottom having a large opening at maximum liquid level and a restricted opening adjacent said bottom, hot water supply means communicating with said compartment for conveying liquid thereto at a rate greater than the drain flow through said restricted opening and lesser than the drain flow through said large opening, a closed receptacle in the hot water supply means between a source and the compartment with the connection to the compartment being at the upper portion of said receptacle whereby liquid flowing through the compartment flows through the receptacle and fills same, an electric heating device in said receptacle for heating water therein and generating steam, control means including a valve in said hot water supply means upstream from said receptacle for permitting flow of hot water through the receptacle and to the washing compartment for a predetermined period and then stopping said flow at the end of said period, an impeller in the washing compartment, an electric motor for operating said impeller to direct Water against articles in said compartment to wash said articles, means forming an energizing circuit including said motor and the electric heater and operative in a sequence whereby the electric motor is operated to drive the impeller during flow of water to the washing compartment and is then stopped and the electric heater energized to generate steam from the water remaining in said receptacle for delivery of said steam after completion of the washing cycle to said washing compartment, said receptacle being of metal having substantial expansion and contraction in response to increase and decrease in temperature, switch means in the electric circuit to the electric heater including normally engaging contacts, and means supporting said contacts for relative movement and re sponsive to expansion of said receptacle by a predetermined increase in temperature above the boiling point of water to separate said contacts and interrupt said energizing circuit to the electric heater.

10. In a dishwashing machine, a washing compartment having a bottom, means supporting articles to be washed in said compartment in spaced relation to said bottom, said compartment having a vent in the upper portion thereof communicating to atmosphere, a drain in the bottom of said compartment having a large opening at maximum liquid level and a restricted opening adjacent said bottom, a vent passage to atmosphere above the maximum liquid level and opening into said compartment below said maximum liquid level whereby said vent passage is closed by liquid when the level is at maximum and is open when the liquid level is drained to below the passage opening in the compartment, hot water supply means communicating with said compartment for conveying liquid thereto at a rate greater than the drain flow through said restricted opening and lesser than drain flow through said large opening, means directing liquid from adjacent the bottom of said compartment against articles therein for a predetermined washing period, a closed receptacle in the hot water supply means bet-ween a source and the compartment with the connection to the compartment being at the upper portion of said receptacle whereby liquid flow to the compartment is through the receptacle and fills same, control means including a valve upstream from the receptacle and operable for controlling flow of liquid to the compartment for a predetermined period of dishwashing cycle and stopping flow at the end thereof, and means for heating the liquid in the receptacle and operable at the end of the predetermined period of washing cycle to heat the liquid remaining in the receptacle at the end of said predetermined period of washing cycle to convert said liquid to steam for discharge through the connection from the receptacle to the compartment whereby said steam condenses on articles in the compartment and provides a distilled water rinse, said steam heating said articles whereby upon completion of the conversion of the water in the receptacle to steam and draining of water from the compartment to a level below the opening of the vent passage in thecompartment allows airto enter through said vent passage and escape through the upper vent of the compartment to facilitate drying of the articles.

References Cited in the file of this patent UNITED STATES PATENTS 855,210 Steward May 28, 1907 1,574,132 Smyser Feb. 23, 1926 1,735,415 Spinney et al Nov. 12, 1929 1,884,180 Pauly Oct. 25, 1932 2,127,778 Lewis Aug. 23, 1938 2,664,094 Spragins Dec. 29, 1953 2,781,765 Steidley Feb. 19, 1957 2,842,144 Lyman July 8, 1958 2,881,780 Johnson et a1 2. Apr. 14 1959 FOREIGN PATENTS 44,507 Norway Oct. 17, 1927 857,428 Germany Nov. 27, 1952

Claims

8. IN A DISHWASHING MACHINE, A CASING DEFINING A WASHING COMPARTMENT HAVING A BOTTOM, MEANS FOR HOLDING ARTICLES TO BE WASHED IN SAID COMPARTMENT IN SPACED RELATION TO SAID BOTTOM, A DRAIN FITTING IN SAID BOTTOM HAVING A LARGE OPENING AT MAXIMUM LIQUID LEVEL AND A RESTRICTED OPENING ADJACENT SAID BOTTOM, HOT WATER SUPPLY MEANS COMMUNICATING WITH SAID COMPARTMENT FOR CONVEYING LIQUID THERETO AT A RATE GREATER THAN THE DRAIN FLOW THROUGH SAID RESTRICTED OPENING AND LESSER THAN THE DRAIN FLOW THROUGH SAID LARGE OPENING, A CLOSED RECEPTACLE IN THE HOT WATER SUPPLY MEANS BETWEEN A SOURCE AND THE COMPARTMENT WITH THE CONNECTION TO THE COMPARTMENT BEING AT THE UPPER PORTION OF SAID RECEPTACLE WHEREBY LIQUID FLOWING THROUGH THE COMPARTMENT FLOWS THROUGH THE RECEPTACLE AND FILLS SAME, AN ELECTRIC HEATING DEVICE IN SAID RECEPTACLE FOR HEATING WATER THEREIN AND GENERATING STEAM, CONTROL MEANS INCLUDING A VALVE IN SAID HOT WATER SUPPLY MEANS UPSTREAM FROM SAID RECEPTACLE FOR PERMITTING FLOW OF HOT WATER THROUGH THE RECEPTACLE AND TO THE WASHING COMPARTMENT FOR A PREDETERMINED PERIOD AND THEN STOPPING FLOW AT THE END THEREOF, AN IMPELLER IN THE WASHING COMPARTMENT, AN ELECTRIC MOTOR FOR OPERATING SAID IMPELLER TO DIRECT WATER AGAINST ARTICLES IN THE COMPARTMENT TO WASH SAID ARTICLES, MEANS FORMING AN ENERGIZING CIRCUIT INCLUDING SAID CONTROL MEANS AND THE ELECTRIC HEATER AND OPERATIVE IN A SEQUENCE WHEREBY THE ELECTRIC MOTOR AFTER FLOW OF WATER TO THE WASHING COMPARTMENT IS STOPPED AND THE ELECTRIC HEATER IS ENERGIZED TO GENERATE STEAM FROM THE WATER REMAINING IN SAID RECEPTACLE FOR DELIVERY OF SAID STEAM AFTER COMPLETION OF THE WASHING CYCLE TO SAID WASHING COMPARTMENT, SAID RECEPTACLE BEING OF METAL HAVING SUBSTANTIAL EXPANSION AND CONTRACTION IN RESPONSE TO INCREASE AND DECREASE IN TEMPERATURE, SWITCH MEANS IN THE ELECTRIC CIRCUIT TO THE ELECTRIC HEATER INCLUDING NORMALLY ENGAGING CONTACTS, AND MEANS SUPPORTING SAID CONTACTS FOR RELATIVE MOVEMENT AND RESPONSIVE TO EXPANSION OF SAID RECEPTACLE BY A PREDETERMINED INCREASE IN TEMPERATURE ABOVE THE BOILING POINT OF WATER TO SEPARATE SAID CONTACTS AND INTERRUPT SAID ENERGIZING CIRCUIT TO THE ELECTRIC HEATER.