US1870317A - Dishwashing machine - Google Patents

Description

9, 1952- E. s. STODDARD ET AL 1,370,317

DISHWASHING MACHINE Filed March 5. 1929 4 Sheets-Sheet l JTLUQTJE'I'S. Edgar Stoddard.

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DI SHWASHING MACHINE Filed March 5. 1929 4 Sheets-Sheet 2 Int/ 9 5.

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DISHWASHING MACHINE Filed March 5. 1929 4 sheets sheet 3 I FIIIIIIIIIIIIII .5

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DISHWASHING MACHINE Filed March 5. 1929 4 Sheets-Sheet 4 Patented Aug. 9, 1932 UNITED STATES PATENT OFFICE EDGAR S. STODDARD, 0F BERWYN, AND WILLARD C. RYKERT, OF CHICAGO, ILLINOIS, ASSIGNOBS TO THE CONOVER COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION- OF ILLINQIS DISHWASI-IING- MACHINE npplicatien filed March 5, 1929. Serial No. 344,111.

. The presentinvention relates to impellers for spraying liquids and particularly relates to impellers for use in the spray-projection type of dishwashing machines.

In these spray-projection machines itiis desirable to utilize a small amount of a cleans ng liquid and to throw the cleansing I liquid tangentially upwardly and outwardly from a low level toward, and upon, dishesand similar objects at a high velocity. The

, dishes at all times are suspended above the level of the pool of cleansing liquid in the bottom of the machine and the cleansing action is exclusively due to the action of a projected or reflected spray. it is desirable to project the liquid spray at. such velocity thatit will have a force sutlicient to tear the adherent dirt from the surfaces ot the dishes and other objects. Y

An object of this invention is to provide an improved impeller for spraying liquids.

formly distribute a small volume of cleans I ing liquid throughout the interior of the washing chamber of the machine.

Other objects will appear during the course of the following description.

The following drawings represent several embodiments of the invention to which the invention, however, is by no means restricted: v

' Figure 1 represents a vertical sectional view of adishwashing machine with the impeller ,in position;

Figures 2, 3 and 4 represent enlarged side andtop views of the embodiment of the impeller shown in Figure 1 Figure 6 1s a top view, illustrating one manner of attachment of the blade shown in Figure 5 to the central cylinder;

Figure 7 is a side sectional View illustrating the driving connections to the impeller; and

Figures 8, 9, l0 and 11 represent side and top views ofimpellers with modified blades.

In Figure 1, the tank of the dishwashing machine 11 is provided with a removable cover 12 and is provided with a depending apron 13. The lower edge of the apron is provided with rollers 14 by means of which the machine may be readily moved about. The impeller is disposed centrally in the lower portion of the tank 11 and is actuated by means of a vertical shaft which extends through the bottom of the tank.

In the tank 11 is positioned a dish rack 31 composed of wires which may be of any suitable construction and is intended to support dishes or similar objects in the space above the impeller and above the pool level. The dishes or other similar objects are so supported by means of the rack 31 that the spray projected by the impeller will contact with them at such an angle as to cleanse them most eliectually. The normal static water level is indicated at 32. It will be noted that the normal static water level may be regulated so that the impeller is only partially immersed.

The water-propelling or circulating device 34 is positioned in the lower central partof the tank and so designed as to elevate small sheets or streams of water from the pool in the lower portion of the vessel at, or closely adjacent to, the central axis of the machine, through a comparatively small compass to a point slightly above the pool level. Such elevated streams of waterare thrownupwardly and outwardly at a high rotational velocity in intermittent or continuous streams or/and sheets. The body of water is so elevated and hurled'or projected that it will be deflected outwardly and upwardly from the dishes towardthe sides and top of the vessel.

surfaces 38 and 39 are of the same size andshape. Continuous with the lower inclined part of the spoon-shaped or concave-shaped projectors are the inclined or screw surfaces 38' and 39 which extend down to a point below the normal surface 32 of the liquid pool in the bottom of the washing chamber of the tank 11. The spoon-shaped deflectors and the downwardly extending inclined surfaces continuous therewith are attached to the outside of the cylinder 35. The downwardly extending surfaces 38 and 39 are similar in shape and function to'those of a screw propeller. The pitch of the inclined surfaces 38 and 39 is such that the water will be elevated rapidly as the impeller is rotated. The downwardly extending inclined surface 38 of the concave projector 36 is cut off at about the same Vertical distance as the similar inclined surface 39. If desired, the inclined surfaces 38 and 39 may be continued downwardly unequal distances so that the lower edge of one surface will'be substantially below the lower edge of the other surface. As shown (see especially Figure 4) the inclined surface 39, attached to the'bottom of the spoon-shaped projector 37, terminates within a short distance about 90 of the commencement of the spoon-shaped deflector on the cylinder 35. It preferably should not extend around the'cyl nder 35 a greater angle than 180 and usually extends around it slightly more than 90. This is also true in the case of the circular inclined surface 38 which continues the concave or spoon-shaped projector portion 36. However, if desired, this latter surface 38 might be continued down and aroundthe shell 35 for an additional distance.

water will be elevated on to the upper portion of the concave projectors as the device is rapidly rotated.

The terminating upper portion of the spoon-shaped projector closely adjacent to its point of attachment 30 to the central cyl-o inder 85 is made approximately vertical as indicated at 40. This vertical surface 40 S10 es backwardly from such point of at The pitch of the . lnclmed surfaces 38 and 39 is such that the dicated at 41 (see Figures 3 and. 4). The relative height of a point on the terminating upper edge of the surface is increased as it is removed' from the cylinder 35, until it rises to a substantial height at point 42 above the top point of attachment to the cylinder 35 (see Figures 2, 3 and 5). The highest point 42 of the spoon-shaped deflector is so positioned that it will be substantially along the center line of the spoon-shaped or concave deflector. The relative diameter and depth of the washing chamber of'the machine and the positioning of the dishes will affect the location of the highest point on the terminating upper edge of the spoonshaped deflector with reference to the inclined surface. The terminating edges of the deflector will fall away from the high point 42.0n both sides, but on the side 43 away from the shaft it will fall away more rapidly in the preferred form.

As the horizontal angular distance of a trace of a vertical radial plane is increased from the point of attachment of the terminating upper edge of the inclined surface to the cylinder 35, the curvature of the trace will decrease in the embodiment shown. The

projector and elevator surfaces are so shaped that the traces of vertical radial planes will be approximately parabolas. The slope of the parabolas will increase as the top of the cylinder is reached starting with a substantially straight radial trace at the bottom of the blade. The water in ascending the elevator and projector surfaces will not rotate at the same speed as the surfaces themselves, due to its slip. The rotational speed of the liquid body on the impeller blade, however, will increase as the top of the blade is approached, starting from almost zero at the bottom of the blade and increasing to a maximum atthe top. The radial trace above described at any place on the surface of the blade should be approximately a parabola of the same shape and value as the arabola which would be formed by the liquid, if rotating in a vessel at the same rotational velocity. The resultin a modified parabo ic surface which at any place will have substantially the same shape and value as the parabolic surface which would be taken by the water upon it, if rotating at the same rotational velocity. This parabolic surface ma be modified. to produce the necessary directional flow or/and distribution of the cleansing fluids.

Starting from the terminating upper edge ofthe inclined surface, the horizontal Width shape of blade will be of the inclined surface increases so that at position of the dishes and the diameters of the dishwashing chamber. From place of maximum width 44, the width of the inclined surface very rapidly decreases until it terminates. The amount of this decrease will be governed by the shape, size and pitch of the bottom of the tank and the amount of Both the concavity and the pitch of the ele% vating'and deflecting surfaces may increase as the top of the impeller is approached as in the embodiment shown. If desired, both lower surfaces and the spoon-shaped deflectors may be made of approximately the same concavity and of approximately the same pitch or inclination. If the inclination is increased it is preferable to decrease the angle of turn around the cylinder so as not to unduly increase the height of the impeller 34. The present inclination varies from about to the horizontal at the bottom to 90 to the horizontal at the top. Vertical tangents to the top of the blade will depart farther and farther from 90 as they are removed from the point of attachment at the top of the cylinder. The vertical tangents closely adjacent to the point of attachment will approximate 90. If desired, the inelination of the entire elevating and deflecting surface may be caused to range from 10 or less to 90 to the horizontal. To increase the concavity of the elevating and deflecting surfaces, the outer terminating edge may be farther elevated and the center of the surfaces may be caused tobe depressed materially below the outer terminating edges.

If the upper edge of the inclined surface is considered to extend from the point of attachment of the surface to the cylinder. to the point where the surface achieves its greatest w'idth, the position of the surface or plane may be considered to be determined by three helicoids or spiraloids or portions of helicoids or spiraloids. The inner spiraloid will be the line of attachment of the surface to the i raloid is formed by the terminating edge of v the elevating and deflecting surface. The central spiraloid will be formed by the center line of the elevating and deflecting surface. In the embodiment of the invention shown on Figures 2 to 5, the radial distance between the spiraloids or helicoids described, increases as they approach the point of maximum width 44. The amount of Vertical depression of the central spiraloid, described, below the outside spiraloid, also increases as the top of the impeller is approached in the embodiment shown. The central spiraloid extends to about the highest point of the impeller while the "inner spiral terminates below the outer spiral.

In the preferred method of construction the symmetrically positioned spiral blades are each made of stamping and are provided with a central fragmentary cylindrical portion 46 (see Figures 5 and 6). These cylindrical portions are adapted to be positioned upon an inner cylinder 47, to which they may be spot-welded or otherwise permanently attached. The upper part of the inner cylinder 47 is closed and may be welded to a nut 48 (see Figure 7 into which the upper part of the impeller shaft is adapted to screw.

The impeller blade and the central cylinder to which they are attached are preferably of stainless sheet steel, but if desired, they maybe constructed of other metals suitably enamelled or coated. If the nut 48is not of stainless steel or a s milar non-corrodible material, it is preferably covered by a staint less steel cap 49. A threaded portion 50 of decreased diameter is provided on the end of the shaft and is adapted to screw into the nut 48 in the same direction as the direction of rotation of the impeller, so that it will not tend to unscrew during operation. The cylindrical shell 47 encloses and surrounds the upwardly projecting tubular bearing (see Figure 7) and will maintain an air pocket upon the place of entrance of the impeller shaft 114 into the tank 11 materially decreasing possibility of leakage. The construction of the impeller 34 may be modified by eliminating the cylindrical shells 35 and 47 and by attaching the'elevating and deflectingsurfaces directly to the central shaft 114. In this case it would be necessary to provide a bearing in thebottom of the tank and suitable stuiflng box arrangements to prevent leakage if-the bearing is submerged in this cleansing fluid. The impeller blades may also be'formed by casting or molding. In

the preferred embodiment of the invention shown, two vanes or blades are utilized. This number, however, may be increased to more than two, or only one vane may be utilized. The impeller 34 is so positioned in the pool that the lower portions of the spoon-shaped deflector will be immersedin the liquid pool whereas the upper portions will be unimmersed during operation. The water-impelling device 34 preferably occupies but'a minor portion of the horizontal internal area of the washing machine and preferably its largest diameter is less than one-third of the interior diameter of the tank. It usually occupies between 1/10 and 1 /35 of the internal horizontal area of the tank. The impeller may be so positioned that it is immersed to about 50% of its height in the static liquid pool, but this may vary between or less and'7 5% or more. The impeller should not in embodiment shown, extend above the normal static water level more than its maximum diameter and it preferably should not extend much more than one-half of its diameter. The top of the impeller may also be substantially below the dishes.

For a tank of 21 diameter the impeller may have an outside diameter of 5 to 7 inches and the blade on inclined elevating and defleeting surface may have a maximum width of 2t-o 3 inches. The impeller is preferably rotated by an inferiorly disposed motor as shown and is direetlydriven thereby at a rate of 1,000 to 3,600 revolutions per minute, preferably about 1,750 revolutions per ,miuute. If it is assumed that this impeller is rotated at a speed'of 1,750 B. P. M. the water projected from its upper surfaces will have an average speed of about 2,500 to 2,600 or more feet per minute. For a tank of 26" diameter, the impeller may have an outside diameter of 6 to 8 inches with a maximum width of deflecting surface of about 2 to 3% inches. If it is assumed that it rotates at 1,750 It. P. M. the peripheral speed of the projected water will be about 2,900 to 3,000 or more feet per minute. In general the diameter of the impeller will vary with the diameterof the tank.

i The impeller when in motion, traveling as it does faster than the water, increases the volume of water on the vanes. It will elevate the required amount of water without the necessity of exterior walls or casings to hold the water on the vanes. At the point where the water leaves the concave pro ector it will be radiated in fan shape approximately along tangents to the circular path of elevation at varying angles to the horizontal. The circular path of elevation in the embodiment shown, is the resultant path due to the two forces acting upon each particle of water, one force upwardly caused by the pitch of the blade and the other outwardly due to the centrifugal force caused by the rotation of the blade.

The greatest volume of water will be delivered at an approximate angle of about to to the horizontal and to the axis of the machine in the embodiments shown in Figures 2 to 5. Substantially all of the liquid will be delivered in a conical band ranging from 20 to 30 on either m'de of the band of greatest volume of water. The major portion of liquid will be thrown out ina band at an jeeting will not commence until the water reaches the height of the portion of maximum width at 44.

As stated above the impeller is preferably driven by an inferiorly positioned motor. The lower portion of the vertical shaft 114 of the impeller is connected by means of the insulating coupling 115 to the upwardly projecting shaft 116 of the motor 117. The motor 117 is suspended from the tank 11 by the casting 118. The casting 1.18 is provided with a central tubular bearing support 120 (see Figures 1 and 7) which is adapted toextend upwardly into the tank to a position above the normal water level. A downwardl facing cup-shaped portion 121 is attache to the lower portion of the central tubular portion 120. At the lower side of the cup 121 is a circular flange 122 which is provided with a circular shoulder 123. The shoulder 123 is adapted to cooperate with the recess 124 in the end bell of the, motor 117 to center the motor and its shaft. The bolts 125 are adapted to bind together the flange 122, and the motor 117 and maintain the cooperating shoulder 123 and recess 124 in position. The end bell of the motor and the bolts 125 are insulated from the bearing member 118 of the machine by washers of insulating material 130 and 131. The sleeve 126 which is fitted into the top of the tubular bearing support 120 by means of a force fit forms an upper bearing while the sleeve 127 by a force tit whit-his fitted into the bottom of the tubular portion 120 forms a lower hearing. The central insulating disk 128 of the coupling 115 preferably consists of a molded piece of hard rubber, bakelite or vulcanized fiber or other insulating material.

In Figures 8 to 11 there are shown modified impellers, which are designed to spray-pro- .ject the liquid with greater force for the same blade area. In these impellers the edge of the projector or the upper surface of the projector is so modified that the liquid will be projected in concentrated, continuous or intermittent streams, rather than sheets. In F igures 8 and 9 a series of buttons 150 are formed on the upper and outer edges of'the projecting portion of the blades decreasing the amount of available area for distributing cleansing liquid by 1/3 to 1/2 or more on each blade.

These buttons may be preferably evenly spaced. In relation to those of the other blades, they should be spaced in the-same or staggered relationship. \Vhen in staggered or complementary relation the buttons or raised portions are positioned so that a space covered by a button on one blade will be left open on the other blade. If it is desired to vary the distribution of the water projected from the blade, the buttons may be increased in number on the area which is to project less liquid, and decreased in number or omittedon the surface which is-to deliver more water.

In Figure 1-1 there is a series of ribs orridges 155 on the surface of the blade. These ribs or ridges are formed adjacent to the edge of the blade and preferably take approximately the direction of the water leavin the blade. They may be arranged in comp ementary or staggered relation and varied in number, as above described, for the same reasons and purposes.

'In both embodiments shown in Figures 8 and 11, the projections 150 and 155 tend to divide the water as it ascends the blade of the impeller into a series of streams which flow in relatively depressed channels 160.

I What is claimed is 1. A spray-projecting impellerof the upright type for use in a dish washing machine, comprising a vertical portion, and a plurality of symmetrically positioned inclined vanes terminating in concave deflectors attached to said vertical portion, said deflectors being provided with raised portions adapted ,to decrease the efiective area thereof, the raised comprising a vertical portion, a

portions being arranged along the discharge edges of said deflectors.

2. A spray-projecting impeller'of the upright type for use in a dishwashing machine,

P symmetrically positioned inclined vanes terminating in concave deflectors attachedv to said vertical portion, said deflectors being provided with raised portions along their discharge edges, the ralsed portions of'one of said reflectors being arranged in complementary relation to the raised portions of another of said deflectors.

In testimony whereof we have hereunto subscribed our names.

EDGAR S. STODDARD. WILLARD O. RYKEBT.

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