US 3415276 A
Description (OCR text may contain errors)
De 10, 1968 w. E. LIND ETAL FLUID CONTROL SYSTEM Filed Dec. 16, 1966 s d, @E md/im, VL. DJM? N /i p W6 M. www, WW W, l
United States Patent O 3,415,276 FLUID CGNTROL SYSTEM Wallace E. Lind, Anoka, and Wynn G. Winkler and Wilbur G. Peyer, St. Paul, Minn., assignors to Whirlpool Corporation, a corporation of Delaware Filed Dec. 16, 1966, Ser. No. 602,216 7 Claims. (Cl. 137-563) This invention relates to fluid control systems and in particular to fluid control systems for use in washing apparatus such as dishwashers.
In apparatus such as dishwashing apparatus, water is forcibly circulated through a washing lchamber by means of a spray arm which is rotated by a suitable motor, the water Ibeing forced upwardly from the arm by a pump also.. driven by the motor. Upon completion of the washing cycle, it is desirable to discharge the spent liquid to a suitable drain. A number of flow control devices have heretofore been employed for controlling this operation of the apparatus. The known devices have had the serious disadvantage of complexity and relatively -high cost. Illustratively, one device provided for this purpose comprises a reversible motor and a second pump arranged to positively pump the spent washing liquid through the discharge line upon reversal of the motor. This apparatus has the serious disadvantage of high cost of the drive motor.
Another device provided for controlling the drain cycle of apparatus such as dishwashing apparatus is a solenoid operated valve in the drain conduit. While such a valve permits the use of a unidirectional pump drive motor, as the drain conduit may be maintained closed against the pumping action of the drain pump such as during the washing cycle, the use of such a solenoid valve in the drain line is relatively expensive and presents a substantial maintenance problem.
Thus, a principal feature of the present invention is the provision of a new and improved fluid control system.
Another feature of the invention is the provision of such a fluid control system having new and improved means for controlling fluid delivery and fluid discharge relative to a washing chamber.
A further feature of the invention is the provision of such a fluid control system having new and improved means arranged for use in conjunction with a unidirectional pump means.
Still another feature of the invention is the provision of such a uid control system wherein fluid pressure in the delivery conduit is utilized in a novel manner to control the open and closed condition of the discharge conduit.
Yet another feature of the invention is the provision of such a fluid control system having new and improved means for providing redundancy in the inlet control means whereby supply of hot water to the dishwashing apparatus may be effectively discontinued notwithstanding the failure of one of the inlet control means.
A yet further feature of the invention is the provision of such a fluid control system including means for receiving a fluid, means defining an inlet passage for conducting fluid under pressure from a source to the receiving means, means defining a discharge passage for conducting the fluid from the receiving means, first valve means for closing the inlet passage at a first point thereof, second valve means for closing the inlet passage at a second point thereof spaced downstream from the the rst point, pressure control means maintaining uid pressure in the portion of the inlet passage between the valves when each of the valves is open to permit flow of the fluid through the inlet passage to the receiving means, means responsive to pressure of the fluid in the inlet passage portion for closing the discharge passage when the Patented Dec. 10, 1968 first valve is open and the second valve is closed and when the first and second valves are concurrently open.
Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawings wherein:
FIGURE l is a fragmentary front elevation of a washing apparatus provided with a liuid control system embodying the invention;
FIGURE 2 is a fragmentary enlarged elevation of a portion thereof; and
FIGURE 3 is a fragmentary transverse section of a modified form of means closing the discharge passage in such a fluid control system.
In the exemplary embodiment of the invention as disclosed in FIGURES 1 and 2 of the drawing, a fluid control system generally designated 10 is shown to comprise a system for controlling the delivery and drain of dishwashing water in a dishwasher apparatus. Thus, illustratively, the system 10 includes a dishwasher tub 11 having a lower sump portion 12 in which is provided a recirculation pump 13 and a drain pump 14 concurrently operated by an electric motor 15. The pump 13 is arranged to pump dishwashing water W upwardly through a shaft 16 and a spray arm 17 to spray upwardly through the dishwashing chamber 18 defined by the upper portion of the tub 11.
The dishwashing liquid W, herein hot water, is delivered into the tub 11 by a supply conduit 19 having an inlet end 20 extending through the wallof the tub 11 into space 18. Means for draining the water W from the tub are provided in the form of a drain conduit 21 having an inlet portion 22 opening to the bottom of the sum-p 12, and an outlet 23 opening as desired, such as to a suitable drain (not shown).
The delivery of the dishwashing liquid W to the tub 11 and drain of the dishwashing liquid therefrom is controlled herein by an improved fluid control system 10 which permits the use of a relatively inexpensive unidirectional motor 15. Thus, the hot water is provided to the conduit 19 from a suitable conventional pressurized hot water supply S. Flow of the hot water through inlet 20 into the tub 11 is controlled by a pair of valves 24 and 25 herein provided with suitable electrical solenoid operators 24a and 25a, respectively, for operation of the valves 24 and 25 under the control of a suitable conventional cycle control 27. Conduit 19 is provided with a branch conduit 28 for providing a fluid pressure signal from the portion 29 of conduit 19 intermediate valves 24 and 25 to a discharge line control generally designated 30. Downstream of valve 25, conduit 19 is provided with a flow restrictor 31 for maintaining a pressure in conduit portion 29 during flow of water through conduit 19 into the tub.
Turning now to FIGURE 2, control 30 is shown to comprise a pressure controlled valve having an armature 32 movable in a Ihousing 33 to selectively compress a flexible portion 34 of the drain conduit 21, thereby to selectively close the drain conduit. The armature may be provided with a boss 3S for localized engagement thereof with the conduit portion 34 to assure effectively positive closure of the drain conduit.
The armature 32 is provided with a head portion 36 engaged lby a exible diaphragm 37 extending across a chamber 38 having an inlet portion 39 communicating with the conduit 28. As shown in FIGURE 2, the body 33 may be sealingly secured to the conduit 28 by a suitable connector such as threaded nut 40.
Thus, when it is desired to provide dishwashing liquid into the tub 11, control 27 is arranged to energize solenoids 24a and 25a to open valves 24 and 25 and allow hot water from supply S to flow through conduit 19 and inlet 20 into the tub 11. During this ow, the flow restrictor 31 causes a pressure to be maintained in the water within conduit portion 29 sufficient to urge diaphragm 37 upwardly, as seen in FIGURE 2, and thereby urge portion 35 of armature 32 against drain conduit portion 34 to close the drain conduit and cause filling of the tub 11 to the desired level. The valve 25 is then closed by de-energization of the solenoid 25a while valve 24 is maintained open by the continued energization of solenoid 24a. Thus, drain conduit 21 is maintained closed by the supply pressure existing in the conduit portion 29, while valve 25 precludes further delivery of hot water from supply S t the tub. The operation of motor 15 at this time causes spraying of the dishwashing water upwardly through the rotating spray arm 17 under the pressure induced therein by recirculating pump 13 thereby to effect the desired washing operation. Although pump 14 is concurrently attempting to pump water W outwardly through inlet 22 of drain conduit 21, the drain control 30 maintains the delivery conduit portion 34 closed and, thus, no draining of the water from the tub occurs at this time.
When it is desired to drain the water W from the tub 11, control 27 causes de-energization of solenoid 2401 to close valve 24 and concurrent energization of solenoid 25a to open valve 25 whereupon the pressure in inlet conduit portion 29 is relieved permitting the armature 32 to move back from drain conduit portion 34 and permit pump 14 to pump the dishwashing water W through drain conduit 21 to the outlet 23 thereof.
Thus, fluid control system provides the highly desirable advantage of permitting the use of the relatively low cost unidirectional motor while yet being extremely simple and economical of construction. At the same time, the control system 10 provides redundancy in the control of the supply conduit 19 as flow of hot water from supply S into the tub 11 may be effectively precluded by energization of either of the solenoids 24a or 25a to close its associated valve. Still further, the pressure operated control 30 avoids the maintenance problems attendant the use of solenoid controlled valves for controlling the drain conduit as in known drain controls.
The invention comprehends the use of any suitable pressure responsive valve means as the control for the drain conduit 21. Thus, as shown in FIGURE 3, a modified control 130 may be employed for selectively closing the drain conduit portion 34. In this modification, control 130 comprises a housing 133 in which is received a liner 141 having a tubular end 142 sealingly connected to conduit 28 by a suitable connector 140 and defining a pressure chamber 138 through which the conduit portion 34 extends. Conduit portion 34 may be suitably sealed to the liner 142 to provide a sealingly closed chamber 138 where by fluid pressure delivered into the chamber 138 causes the drain portion 34 to close preventing drainage of sump 12 and the release of pressure in chamber 138 causes drain portion 34 to expand to its open position, as shown in FIGURE 3, to permit drain flow therethrough. Thus, the control 130 functions substantially similarly to flow control 30 in the operation of the fluid control system.
While we have shown and described certain embodiments of our invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construtcion and arrangement may be made without departing from the spirit and scope of the invention as defined in the appended claims.
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. A fluid control system comprising:
means for receiving a fluid;
means defining an inlet passage for conducting fluid under pressure from a source to said receiving means; means defining a discharge passage for conducting the fluid from said receiving means;
first valve means for closing said inlet passage at a first point thereof;
second valve means for closing said inlet passage at a second point thereof spaced downstream from said first point;
pressure control means maintaining fluid pressure in the portion of said inlet passage between said valves when each of said valves is open to permit flow of the fluid through said inlet passage to said receiving means; and
means responsive to pressure of the fluid in said inlet passage portion for closing said discharge passage when said first valve is open and said second valve is closed and when said first and second valves are concurrently open.
2. The fluid control system of claim 1 wherein said pressure control means comprises flow restrictor means providing a pressure drop in the fluid downstream of said inlet passage portion.
3. The fluid control system of claim 1 wherein means are provided for pumping fluid under pressure from said receiving means through said discharge passage and said discharge passage closing means is arranged to close said passage against said pumping pressure.
4. The fluid control system of claim 1 wherein said fluid comprises water and said receiving means defines a washing chamber.
5. The fluid control system of claim 1 wherein means are provided for circulating the fluid in said receiving means when said second valve is closed and said first valve is open to cause said discharge passage closing means to close said discharge passage.
6. The fluid control system of claim 1 wherein said discharge passage means includes a flexible portion and said discharge passage closing means comprises means for constricting said portion to block said discharge passage when the pressure in said inlet passage portion is at least the pressure maintained by said pressure control means.
7. The fluid control system of claim 1 wherein said receiving means comprises a dishwasher tub, said fluid comprises water, means are provided for circulating the water in said tub for washing dishes therein and for cycling said valves to (a) open both valves to deliver water to said tub while maintaining said discharge passage closed,
(b) close said second valve while maintaining said first valve open to discontinue delivery of water to said tub while maintaining said discharge passage closed and concurrently operating said circulating means, and
(c) closing said first valve and opening said second valve to open said discharge passage and permit said water to be discharged from said tub.
References Cited UNITED STATES PATENTS 2,619,037 11/1952 OConnor et al. 137-563 XR 2,895,505 7/ 1959 Bachus 251-5 XR 3,331,374 7/1967 Stewart et al. 134-56 3,350,053 10/1967 Schmitz 251-5 FOREIGN PATENTS 710,636 9/1941 Germany.
ROBERT L. BLEUTGE, Primary Examiner.
U.S. Cl. X.R.