US2662536A - Drainage control system - Google Patents

Description

1953 L. J. MARTINIAK ETAL ,6

DRAINAGE CONTROL SYSTEM Filed Nov. 28, 1952 Patented Dec. 15, 1953 DRAINAGE CONTROL SYSTEM Leonard .1. Martinialr, Chicago, and John W. Duscnberry, Melrose Park, Ill., assignors to General Electric Company, a corporation of New York Application November 28, 1952, Serial No. 323,032

10 Claims.

This invention relates to improvements in drainage control systems for dishwashing machines in which an impeller or screw is driven at relatively high speed to cause washing and rinsing liquid to be brought forcefully into contact with. the articles contained in a dishwasher tub.

In dishwashing machines of the domestic type particularly, it is a practical necessity to conserve water. As a result each washing or rinsing operation uses, in a presently well-known domestic dishwasher, only about twelve pints of water which is recirculated many times over the articles to be washed and rinsed. Drainage loss must be prevented during the washing or rinsing operations and yet the drainage system must provide for quickly removing the liquid at the end of the operation. Drain valves as presently known and used require electrically or mechanically timed devices to operate them between open and closed positions and are subject not only to failures of such timing devices but to sticking or other faulty operation due to the lodgement of food particles.

It is an object of our invention to provide a valve mechanism directly associated with the impeller so as to be open when the impeller is quiet, but automatically assuming a closed position in response to centrifugal forces generated by impeller rotation.

It is another object of the invention to provide a valve member having a plurality of individually relatively small drainage ports, thereby reducing leakage if one of the valve elements is held partially open during a non-drainage period.

It is another object of the invention to provide a valve mechanism fixed to the impeller to rotate therewith and effective solely by reason of its rtation to prevent the flow of liquid to a drainage opening disposed about the axis of rotation of the impeller.

It is a still further object or" the invention to provide a valve mechanism which may easily be repaired or replaced in the field without requiring other than a removal of the impeller.

In a presently preferred embodiment of our invention, these and other objects and advantages are accomplished by providing a cylindrical valve body member with a plurality of drain ports extending upwardly from one edge thereof and providing on the interior of said valve body an equal number of resilient flaps normally biased away from said ports but operable under centrifugal forces engendered by rotation of said body to move into port-closing position. The said body is then suitably mounted within the hub of the impeller, with the bottom edge of the body closely adjacent the dishwasher tub bottom. The drainage opening of the tub is disposed concentrically about the impeller shaft. When the impeller is quiet following a washing or rinsing operation, the resilient flaps withdraw from the ports, thus permitting liquid in the tub to reach the drainage opening. On the other hand, when the valve is rotating with the impeller, the valve flaps swing into closing position, thus preventing the water content of the tub from reaching the .rainage opening. We have found that by making the valve body of a material having a wall thickness of the order of of an inch, edge walls of the valve ports create a turbulence within the body of the liquid when the impeller is rotating rapidly. This turbulence is remarkably effective to prevent water from reaching the interior of the valve and therefore supplements the valve elements in preventing unwanted drainage.

Other features and advantages of the invention will be apparent from the following detailed description of embodiments thereof read in connection with the accompanying drawing in which:

Fig. 1 is a fragmentary sectional elevation of the bottom of a dishwasher tub showing an application of one embodiment of our invention. The impeller is quiet, permitting any water content to drain as indicated by the arrows;

Fig. 2 is a section through the valve portion along the lines 2-2 of Fig. 1 showing the several valve elements in drainage position;

Fig. 3 is a view similar to Fig. 2 with the valve ports closed during rotation of the impeller; and

Figs. 4 and 5 are respectively a vertical section and a plan section showing a second form of valve construction.

In Fig. 1 there is fragmentarily shown the lower tub portion of a dishwasher of the type, for example, fully described in Koertge U. S. Patent 2,422,022 granted June 10, 1947, for Dishwashing and Drying Apparatus. In dishwashers of this type, a tub I is suitably supported within an outside casing (not shown). The tub has an open front and the casing pivotally supports a door movable between a substantially vertical closed position and a substantially horizontally open position. Within the tub are dish racks (not shown) arranged to be drawn outwardly through the open front of the tub loaded with dishes and returned to the tub; whereupon detergent may be added, the door closed and the dishwasher operated.

By various means new well-known in the art, the dishwasher proceeds through a program involving timed operations in which the dishes are rinsed, washed, given one or more rinses following washing, and then are air-dried. Each of the rinsing and washing operations requires the introduction into the tub of about twelve pints of water, and after each such operation the water is caused to drain from the tub. With specific reference to the instant disclosure, the wash and rinse liquid is circulated and recirculated over the articles within the tub by a motor-driven impeller or screw 2, removably fixed to the vertical shaft extension 3 of the motor l, attached by any suitable brackets 5 to the bottom of the tub or alternatively to a drainage fitting i3 suitably secured to said tub in watertight relation therewith. As shown, said drainage fitting may comprise a casting having an annular water collector channel I, sloping toward a discharge tube 8 to which may be aiiixed in any suitable manner a pipe 9 communicating with a drain trap (not shown) in the plumbing system of the building. Rising from the central portion of the drainage fitting is a tubular guard it which extends upwardly about shaft 3 to a level which prevents liquid in the tub from spilling into the open end of said tube and flowing into the motor space. Removably disposed about said impeller is a screen i i; and fixed within the tub and surrounding the impeller, so as to be in the path of air circulation during the final dish drying stage of operation, is a metallic sheathed heating element 1?! as specifically disclosed in said Koertge patent.

The bottom of the tub I slopes to form a sump, at the center of which is an opening Hi compri ing the only drainage opening from the dishwasher tub. The present invention provides a simple and effective control over the drainage of spent wa hing and rinsing liquid.

It will be understood that shaft 3 rotates at high speed: in the usual domestic dishwasher, a 1750 R. P. M. motor is used. It is assumed that the shaft will rotate in a counter-clockwise direction.

In the embodiment Figs. 1, 2 and 3, the valve device includes a cylindrical body is sized to fit snugly within the cylindrical hub of the impeller 2 in surface contact with the inner wall thereof. At intervals about the lower portion of said body, we provide a plurality of valve ports H5 which are advantageously of rectangular cross section. Preferably the valve ports comprise rectangular notches open at the bottom and extending upward a proximately to the plane of the bottom of the impeller hub. When the valve body is in proper operative position, the bottom wall of the tub becomes in effect the fourth wall of the valve port opening, although it should be noted that it is not necessary for the bottom ed e of the valve body to be in actual surface contact with the tub. Cooperating with each valve port is a flapper valve member ll secured at one end to the valve body and arranged to move between a normally retracted or open position shown in 2 and the closed position of Fig. 3, in which the flapper valve effectively closes the valve port against escape of liquid. It is apparent from Fig. 3 that the flapper valve is sufficiently longer than the port It to insure a substantial overlap at the end of the valve port, and in this way prevent the flapper valve from driving through the valve port as it swings closed by centrifugal force as later explained.

The flapper valves are of resilient material biased to assume a normally open position. Various constructions are possible: body it may, for example, be of rigid plastic and the flapper valves of a resilient or springable material suitably afilxed thereto. We consider, however, that it is best to mold the body and flapper valves of an elastomeric material such as natural rubber compounds or plastics such as that marketed under the name neoprene in which event the flapper valves are integral with the valve body. A medium-stiff rubber in the 60-70 clurometer range appears to be well suited to the purpose.

In the embodiment of Figs. 4 and 5, the valve body 15.! is similarly formed with valve ports l6.l. The flapper valves I'M are arranged to pivot in a vertical rather than a horizontal plane. The fiappers are biased into the normally open position of Fig. 4.- and to limit the extent of movement in valve closing direction, we propose to bevel the side Walls of the valve ports so that their maximum width is radially innermost. By matchingly bevelling the side walls of the flapper valves, the valves will seat snugly into the valve ports without substantial danger of driving through the ports.

It will thus be seen that we have provided a drainage control system in which it is necessary only to interrupt the operation of the impeller whenever washing or rinsing liquid is to flow to the drain. During a preliminary rinse period, for example, when gross soil is to be removed from the dishes before an actual washing operation takes place, rinse water is introduced into the dishwasher tub while the impeller is silent, whereupon the water will flow over the dishes and articles and then pass through the open valve ports into the drainage system. The next operation would be to wash the articles and therefore before the water is caused to flow into the tub the timing apparatus (not shown) starts the motor so that the impeller will be approachina its operation speed before the water enters. As the impeller gains speed, centrifugal forces acting on the flapper valves 5! or NJ throw them outwardly into closing position. Then at the end of or slightly before the termination of the washing operation, the motor circuit is opened so that the impeller will cease rotating. The valve elements return to their normally open position, permitting full drainage. Using a plurality of relatively small valve ports and fiappers makes an individual port less critical. That to say, a valve flapper might be held partially open by a foreign body without causing excessive water loss. Conversely, adequate drainage is provided for even if one of the flapper valves should stick in closed position.

By sizing the valve cylinders l5 and I5.| for frictional engagement with the inside of the impeller hub, it is not necessary mechanically to fasten the valve cylinder to the impeller to insure rotation therewith. This simplifies installation and. removal. For example, to remove the valve body for inspection or repair, it is necessary only to remove the impeller from its shaft and then to remove and replace the cylindrical valve body as necessary. The impeller is readily accessible through the open door of the dishwasher tub. This facility of inspection and removal makes it entirely unnecessary to dismantle the dishwasher apparatus as is now required to service most of the conventional domestic dishwashers.

We have discovered that in the Fig. 3 form particularly, the square vertical wall of each valve port 16 causes a. turbulence in the sump immediately around the valve body which appears to throw the liquid away from the valve member This action is particularly effective when the valve body is of the order of one-eighth inch in thickness. This turbulence-creating action in a sense assists the valve flapper members in preventing loss or" liquid.

While we have shown particular embodiments of our invention, it will be understood, of course, that we do not wish to be limited thereto since many modifications may be made; and we there fore contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of our invention.

We claim:

1. In a dishwashing machine of the type having a tub for containing articles to be washed in a quantity or" liquid and a motor driven impeller disposed adjacent a wall of said tub for rotation about a fixed axis to distribute said liquid throughout said tub; the improvement in means for controlling drainage from said tub, comprising a drainage opening in said tub Wall about impeller axis, a cylindrical valve body associated with said impel er for rotation therewith, said valve body extending from said impeller to encircle said drainage opening in close proximity to said tub wall, said valve body having about its circumference a plurality of openings disposed immediately adjacent said tub wall, and a flapper valve pivotally carried said valve body interiorly thereof for cooperation with each said valve body opening, the respective flapper valves being biased away from their associated valve openings to permit flow therethrough when said impeller is at rest but responsive to centrifugal forces engendered by rotation of said impeller to move against valve body to close said openings.

2. In a dishwashing machine of the type having a tub for containing articles to be washed in a quantity of liquid and a motor driven impeller disposed adjacent a wall of said tub for rotation about a fixed axis to distribute said liquid throughout said tub; the improvement in means for controlling drainage from said tub, comprising a drainage opening in said tub wall about said impeller axis, a cylindrical valve body carried by said impeller for rotation therewith, said valve body extending from said impeller to encircle said drainage opening in close proximity to said tub wall, said valve body having about its circumference a plurality of openings disposed immediately adjacent said tub wall, and valve means pivotally carried by said valve body interiorly thereof for cooperation with each said valve body opening, said valve means being biased inwardly away from their associated valve openings to permit flow therethrough when said impeller is at rest but responsive to centrifugal forces engendered by rotation of said impeller to move outwardly against said valve body to close said openings.

3. In a dishwashing machine of the type hav ing a tub for containing articles to be washed in a quantity of liquid and a motor driven impeller disposed adjacent a wall of said tub for rotation about a fixed axis to distribute said liquid throughout said tub; the improvement in means for controlling drainage from said tub, comprising a drainage opening in said tub wall about said impeller axis, a cylindrical, water-impervious valve body associated with said impeller for rotation therewith, said valve body extending coaxially from said impeller to encircle said drainage opening in close proximity to said tub wall, said valve body having formed in its wall equidistantly about its circumference a plurality of open-ended passages in which the open ends face said tub wall, and a flapper valve by said valve body for cooperation with each said valve body opening, the respective flapper valves boing pivotally affixed to said valve body at the leading edge of each said passage as respects the direction of rotation of said valve body and ex tending interiorly of said body into overlapping relation with said body wall beyond the trailing edge of said passage, said flapper valves being biased away from their associated body wall passages to permit flow therethrough when said impeller is at rest but responsive to centrifugal forces engendered by rotation of said impeller to move against said valve body to close said openings and thereby prevent flow of liquid to said drainage opening.

4. Drainage control means as in claim 3, in which said flapper valves are integral with said valve body,

5. Drainage control means as in claim 3, in which said flapper valves and said valve body are integral and of a semi-stiff elastomeric material having the resiliency characteristic of rubber of 60-70 durometer.

6. Drainage control means as in claim 3, in which said flapper valves pivot about an axis parallel to the axis of rotation of said impeller.

7. In a dishwashing machine of the type having a tub for containing articles to be washed in a quantity of liquid and a motor driven impeller disposed adjacent a bottom wall of said tub for rotation about a fixed vertical axis to distribute said liquid throughout said tub; the improvement in means for controlling drainage from said tub, comprising a drainage opening in said bottom wall radially outward of said impeller axis, a cylindrical valve body frictionally secured to said impeller for rotation therewith, said valve body extending coaxially from said impeller to encircle said drainage opening in close proximity to said tub wall, said valve body having about its circuinference a plurality of openings disposed immediately adjacent said tub wall, and a flapper valve carried by said valve body for pivotal movement about a vertical axis for cooperation with each said valve body opening, each said flapper valve axis being in the leading portion of said opening as respects the direction of rotation of said impeller, the respective flapper valves extending inwardly of said valve body into overlapping relation with the wall thereof rearwardly of the trailing edge of the associated valve openings and being biased with respect thereto to permit flow therethrough when said impeller is at rest but responsive to centrifugal forces engendered by rotation of said impeller to move against said valve body to close said openings.

8. Drainage control means as in claim 7, in which the trailing edge of each said valve opening cooperates with its associated flapper valve when the latter is in closing position to define a substantially triangular pocket effective to create turbulence in a body of liquid about said valve body and to repel such liquid from said valve body.

9. In a dishwashing machine of the type having a tub for containin articles to be washed in a quantity of liquid and a motor driven impeller at the bottom of said tub for rotation about a fixed axis to distribute said liquid throughout said tub; the improvement in means for controlling 7 drainage from said tub, comprising a drainage opening in said tub wall about said impeller axis, a cylindrical valve body of semi-stiff rubberlike material secured to said impeller for rotation therewith, said valve body extending ooaxially from said impeller to encircle said drainage opening in close proximity to said tub wall, said valve body formed about its circumference with a plurality of relatively small, equiangularly spaced openings, and a flapper valve horizontally pivoted about each said opening and extending downwardly into operative relation therewith, said flapper valves being normally biased to move radially inward of said valve body to uncover said openings for liquid flow therethrough when the impeller is at rest but moving in response to centrifugal forces engendered by rotation of said impeller to close said openings.

10. Drainage control means as in claim 9, in which the side edges of said valve body openings are beveled to enlarge said openings in a radially inward direction and the side edges of said flapper valves are matchingly beveled.

LEONARD J. MARTINIAK. JOHN W. DUSENBERRY.

No references cited.

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