Patent Application
20130205843
The subject matter of the present disclosure relates generally to a dispensing system for an appliance.
A washing machine appliance can use a variety of fluids (in addition to water) to wash and rinse laundry and other articles. For example, laundry detergents and/or stain removers may be added during wash and prewash cycles. Fabric softeners may be added during the rinse cycles.
These fluid additives must be introduced at an appropriate time during the cleaning process and in a proper amount. By way of example, adding laundry detergent and fabric softener at the same time into the water used for a laundry load is undesirable because the resulting mixture is unlikely to clean or soften as the two will negate each other. Not adding enough of either the detergent or softener to the laundry load will diminish the efficacy of the cleaning process. Conversely, adding too much detergent or softener is also undesirable.
For instance, when too much detergent is added during a wash cycle, this can leave some detergent that remains on the clothes because the rinse cycle of a washing machine may not be able to remove all of the detergent used during the wash cycle. In turn, this can lead to a graying effect on the clothes as the detergent builds up over time, can contribute to a roughness feeling, and potentially may even affect skin allergies. The excess detergent can also negatively affect the efficacy of the fabric softener during the rinse cycle. Excess detergent can also cause excess suds which may be undesirably left on the clothes after a wash cycle, cause damage to the washing machine, and/or cause the spin speed to decrease therefore causing the clothes to retain too much water.
As a convenience to the consumer, systems for automatically dispensing detergent and/or fabric softener can be provided. Such automatic systems can store one or more fluid additives in bulk and dispense at the appropriate times during a wash cycle. Challenges are still encountered, however, in metering the appropriate amount of the fluid into a wash or rinse cycle with such automatic systems. For example, hoses or other conduits are typically used to route the fluid from the bulk dispense containers to the wash bin. For a variety of reasons, air can be introduced into these hoses and create gaps in the fluid delivery. As a result, simply activating e.g., a pump or other fluid delivery device for a predetermined amount of time may not provide for an accurate dispense since the air will displace some of the volume intended for fluid. Thus, in order to ensure that the proper amount of fluid is delivered, these gaps must either by eliminated or otherwise accounted for during use of the appliance.
Accordingly, a system for metering a fluid in an appliance would be useful. More particularly, a system that can enhance the delivery of accurate amounts of an fluid additive during a wash or rinse cycle would be beneficial. Such a system that can properly treat e.g., air in the delivery system would be very useful.
Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In one exemplary embodiment of the present invention, a system for dispensing a fluid in an appliance is provided. The system includes a tank for storing the fluid and a pumping device for drawing fluid from the tank. The pumping device has an inlet and an outlet. The inlet is connected to receive fluid from the tank. A pressure sensor is configured between the tank and the pumping device to provide one or more pressure measurements. The system also includes at least one processing device that is configured to manipulate the pumping device so as to draw fluid from the tank, receiving pressure measurements of the fluid from the pressure sensor, and determining when the pressure measurements of the fluid become substantially constant after the step of activating the pumping device.
In another exemplary aspect of the present invention, a method for dispensing a fluid in an appliance is provided. The method includes the steps of providing a supply of the fluid for delivery in the appliance; causing the fluid to flow along a path from the supply to a wash chamber of the appliance; measuring the pressure of the fluid along the path during said step of causing; and, determining when the pressure of the fluid becomes constant along the path during the step of causing the fluid to flow.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
The present invention provides for a bulk fluid dispensing system that can prime itself so as to remove e.g., air gaps that might affect the metering of a proper amount of the fluid into a wash chamber or wash bin of the appliance. A pressure sensor can be used to determine when the air gaps have been eliminated. Other features can be provided as well. Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
A backsplash 56 extends from cover 54, and a control panel 58 including a plurality of input selectors 60 is coupled to backsplash 56. Control panel 58 and input selectors 60 collectively form a user interface input for operator selection of machine cycles and features. For example, in one embodiment, a display 61 indicates selected features, a countdown timer, and/or other items of interest to machine users. A door or lid 62 is mounted to cover 54 and is rotatable about a hinge (not shown) between an open position (not shown) facilitating access to wash tub 64 located within cabinet 52, and a closed position (shown in
Referring now to
An agitation element 76, such as a vane agitator, impeller, auger, or oscillatory basket mechanism, or some combination thereof is disposed in basket 70 to impart an oscillatory motion to articles and liquid in basket 70. In different embodiments, agitation element 76 includes a single action element (i.e., oscillatory only), double action (oscillatory movement at one end, single direction rotation at the other end) or triple action (oscillatory movement plus single direction rotation at one end, singe direction rotation at the other end). As illustrated in
Operation of machine 50 is controlled by a controller or processing device (not shown) that is operatively coupled to a control panel or user interface input 58 located on washing machine backsplash 56 (shown in
In an illustrative embodiment, laundry items are loaded into basket 70, and washing operation is initiated through operator manipulation of control input selectors 60 (shown in
After the agitation phase of the wash cycle is completed, tub 64 is drained with the pump assembly. Laundry items are then rinsed and portions of the cycle repeated, including the agitation phase, depending on the particulars of the wash cycle selected by a user. One or more spin cycles may also be used. In particular, a spin cycle may be applied after the wash cycle and/or after the rinse cycle in order to wring wash fluid from the articles being washed. During a spin cycle, basket 70 is rotated at relatively high speeds. Preferably, basket 70 is held in a fixed position during portions of the wash and rinse cycle while agitator 76 is oscillated as described. During portions of the spin cycle, basket 70 is also rotated to help wring fluid from the laundry articles through holes 74.
As previously indicated, one or more fluid additives such as detergent, fabric softener, etc. may be added to the wash tub 64 (or other chamber or bin of an appliance) during the above-described cycles. For convenience to the user, an automatic dispensing system can be provided by which such fluid additives are automatically dispensed. Such system can be equipped with e.g., at least one processing device for controlling the system according to one or more methods as described herein.
Tank 105 is connected to a pumping device 110 by a fluid conduit 115. Pumping device 110 could be e.g., a positive displacement pump such as a peristaltic pump. Pumping device 110 could be an aspirator connected with e.g., a water supply to draw the fluid additive from tank 105. Other pumping devices may be used as well.
Fluid conduit 115 could be e.g., one or more fluid channels constructed from hoses, tubes, and/or pipes extending between tank 105 and pumping device 110. For example, tank 105 may located near the bottom of the appliance such that tube 115 extends from a connection at or near the bottom of tank 105 to pumping device 110. Similarly, fluid conduit 125 delivers fluid from the outlet of pump 110 to wash chamber or tub 64.
A processing device or controller 135 is used to operate pumping device 110 so as draw fluid 120 from tank 105 and deliver the same to wash bin 64. As such, pumping device 110 can be used to meter fluid 120 into wash bin 64. For example, knowing the rate of flow available from pumping device 110, controller 135 can operate pumping device 110 for a predetermined time interval so as deliver the desired amount of fluid additive from tank 105. Shorter time intervals can be used to deliver less fluid and longer time intervals can be used to deliver more fluid. Where pumping device 110 is e.g., an aspirator, a valve (such as e.g., the control valve for a water supply) or pump (such as e.g., a pump connected with a water supply) positioned upstream of pumping device 110 can be similarly controlled so as to draw fluid 105 from tank 120. Other configurations may be used as well.
As indicated above, one challenge that can occur in the operation of automatic dispensing systems is the introduction of air or other gaps into the lines providing the fluid additive. Referring to system 100, air can enter fluid conduit 115 and become positioned between tank 105 and pumping device 110. For example, if tank 105 is disconnected from conduit 115 for replacement or refill, fluid may drain from conduit 115 and be replaced by air that will be trapped in conduit 115 once tank 105 is reconnected or replaced. Similarly, depending upon the particular orientation of conduit 115 within the appliance, gravity can cause fluid in conduit 115 to empty from conduit 115 and return into tank 105. For example, referring to
Depending upon the size of conduit 115, the introduction of air into conduit 115 can cause significant error in the metering of fluid 120 based on the time of operation of pumping device 110. More specifically, until pumping device 110 is properly primed with fluid 120, only air will be delivered into conduit 125 so as to reduce the quantity of fluid 120 delivered for a given time interval. For example, suppose that a properly primed pumping device 110 can deliver the required quantity of fluid additive 120 by being activated for 30 seconds. If processing device 135 activates pump device 110 for 30 seconds, but 15 seconds are spent removing air before fluid reached pumping device 110, then only half the desired quantity of fluid will be delivered. Thus, it is important to determine when pumping device 110 is properly primed with fluid 105. More particularly, in order to meter the desired quantity of fluid 120 into tub 64, the time at which air gaps have been removed so that fluid 120 has reached pumping device 110 must be determined
As shown in
When pumping device 110 has been inactive for some period of time, fluid 120 in conduit 115 will assume the same level, L1, as in tank 105. In this position, pressure sensor 140 will provide a measurement of the static head from fluid 120, which can be used to determine the amount of fluid remaining in tank 105. For example, knowing the pumping device 110 is not activated, processing device 135 can receive pressure measurements from sensor 140 and notify the user of the amount of fluid remaining in tank 105 and/or provide a notification whenever the fluid falls below some predetermined level that is indicative of an upcoming refill requirement.
Once the user activates appliance 50, however, eventually processor 135 will call for fluid to be dispensed into wash bin 64, and pump 110 will be activated. At this point, only air is present between pumping device 110 and fluid level L1 (as shown by arrows A) As pumping device 110 operates, fluid 120 will be drawn along conduit 115 in the direction of arrow U. During such time, the pressure as measured by sensor 140 will fluctuate—change constantly as the fluid moves toward pumping device 110. While such pressure measurements fluctuate, processing device 135 will “know” that air is being purged from conduit 115 and fluid has not yet reached pumping device 110. As a result, where the metering of pumping device 110 is controlled e.g., by a time interval, processing device 135 will not initiate a timer or other determination of such interval.
Upon fluid 120 reaching pumping device 110, the pressure as measured by pressure sensor 140 will stabilize or become substantially constant. Once processing device 135 receives pressure measurements indicating the pressure has stabilized, pumping device 110 is primed. Processing device 135 can then begin to meter fluid using pumping device 110. For example, processing device 135 can then begin a timer to operate pumping device 110 for a given time interval so as to deliver the desired amount of fluid 120 into wash bin 64. The length of such time interval might be calculated or determined by processing device 135 based upon e.g., the size of the laundry load in wash bin 64.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
