Patent Application
20200216998
The present disclosure relates generally to washing machine appliances and more particularly to washing machine appliances with improved bulk additive dispensing systems.
Washing machine appliances can use a variety of wash additives (e.g., a detergent, fabric softener, and/or bleach) in addition to water to assist with washing and rinsing a load of articles. For example, detergents and/or stain removers may be added during wash and prewash cycles of washing machine appliances. As another example, fabric softeners may be added during rinse cycles of washing machine appliances. Wash additives are preferably introduced at an appropriate time during the operation of washing machine appliance and in a proper volume. By way of example, adding insufficient volumes of either the detergent or the fabric softener to the laundry load can negatively affect washing machine appliance operations by diminishing efficacy of a cleaning operation. Similarly, adding excessive volumes of either the detergent or the fabric softener can also negatively affect washing machine appliance operations by diminishing efficacy of a cleaning operation.
As a convenience to the consumer, certain washing machine appliances include systems for automatically dispensing detergent and/or fabric softener. Such systems may include a bulk storage tank that can store one or more wash additives in bulk and dispense such wash additives during operation of the washing machine appliances. Certain such washing machines include an aspirator assembly, which uses a Venturi pump to provide a cost-effective and easy way for dispensing wash additive. Specifically, a water regulating valve may be used to provide a flow of water through a Venturi pump having a suction line coupled to the additive reservoir for drawing in and mixing with wash additive.
However, accurately dispensing a particular volume of wash additive with such systems can be difficult. In this regard, conventional Venturi-based wash additive dispensing systems attempt to control the volume of dispensed wash additive by controlling the “dispense duration” of water through the Venturi pump. However, because a Venturi pump relies on suction (negative pressure) in order to pull wash additive from the additive reservoir, the dispensing system is highly sensitive to both the viscosity of the wash additive and the level of the wash additive in the additive reservoir.
Notably, the kinematic viscosities of wash additives available on the market can range from about one hundred fifty to over one thousand centistokes (150-1,000 cSt). In instances where the viscosity of the wash additive is relatively low, the Venturi pump may dispense too much wash additive, and in instances where the viscosity of the wash additive is relatively high, the Venturi pump may dispense too little wash additive. In addition, as the level of the wash additive in the additive reservoir is lowered through repeated operating cycles, the Venturi pump typically delivers less wash additive during the fixed dispense duration.
Despite the wide ranging viscosities of wash additives used in washing machine appliances and the range of wash additive levels experienced, the “dispense duration” of the Venturi pump is generally not modified or altered to compensate for such variations. Accordingly, conventional Venturi-based dispensing systems rarely achieve the proper volume of wash additive for achieving optimal wash performance, resulting in inefficient use of the wash additive and poor wash performance.
Accordingly, a washing machine appliance having features for improving the dispensing of wash additives would be useful. More particularly, a Venturi dispensing system for easily and accurately dispensing wash additive from a bulk reservoir of a washing machine appliance would be especially beneficial.
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 disclosure, an additive dispensing system for a washing machine appliance is provided. The additive dispensing system includes a bulk storage tank defining an additive reservoir for receiving a wash additive, a tank level sensor for measuring a level of wash additive in the additive reservoir, and an aspirator assembly comprising a Venturi pump, a water supply conduit, and a suction line, the suction line fluidly coupling the Venturi pump and the additive reservoir such that the Venturi pump draws wash additive from the additive reservoir when a flow of water flows through the Venturi pump. A water regulating valve is operably coupled to the water supply conduit for selectively providing the flow of water through the Venturi pump of the aspirator assembly. A controller is operably coupled to the tank level sensor and the water regulating valve and is configured for measuring the level of wash additive in the additive reservoir using the tank level sensor, determining an additive dispense rate based at least in part on the level of wash additive in the additive reservoir, and selectively dispensing the flow of water through the aspirator assembly based at least in part on the additive dispense rate to dispense a target volume of the wash additive.
In another exemplary aspect of the present disclosure, a method for dispensing wash additive from an additive reservoir is provided which uses a Venturi pump fluidly coupled to the additive reservoir through a suction line such that the Venturi pump draws wash additive from the additive reservoir when a flow of water flows through the Venturi pump. The method includes measuring a level of wash additive in the additive reservoir using a tank level sensor, determining an additive dispense rate based at least in part on the level of wash additive in the additive reservoir, and selectively dispensing the flow of water through the Venturi pump based at least in part on the additive dispense rate to dispense a target volume of the wash additive.
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.
Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.
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. As used herein, terms of approximation, such as “about” and “approximately,” refer to being within a ten percent (10%) margin of error.
While described in the context of a specific embodiment of vertical axis washing machine appliance 100, using the teachings disclosed herein it will be understood that vertical axis washing machine appliance 100 is provided by way of example only. Other washing machine appliances having different configurations, different appearances, and/or different features may also be utilized with the present subject matter as well, e.g., horizontal axis washing machines.
Washing machine appliance 100 has a cabinet 102 that extends between a top portion 104 and a bottom portion 106 along the vertical direction V. A wash tub 110 (
Cabinet 102 of washing machine appliance 100 has a top panel 120, e.g., at top portion 104 of cabinet 102. Top panel 120 defines an opening 122 that permits user access to wash basket 112 of wash tub 110. A door 124 is rotatably mounted to top panel 120 and permits selective access to opening 122; in particular, door 124 selectively rotates between the closed position shown in
Top panel 120 may also define one or more apertures for receiving various wash additives. For example, according to the exemplary illustrated embodiment, top panel 120 defines a reservoir inlet 132, at a corner of top panel 120 at or adjacent a front portion of top panel 120. Reservoir inlet 132 permits the wash additive to pass through top panel 120 and into an additive reservoir (described below) disposed below top panel 120 along the vertical direction V. Thus, a user may pour the wash additive into the additive reservoir through reservoir inlet 132 in top panel 120. According to alternative embodiment, top panel 120 may define additional openings configured for receiving any suitable wash additives, e.g., including various fluid or powder additives such as detergent, fabric softener, and/or bleach.
A control panel 140 with at least one input selector 142 (
Controller 146 may include a memory and microprocessor, such as a general or special purpose microprocessor operable to execute programming instructions or micro-control code associated with a cleaning cycle. The memory may represent random access memory such as DRAM, or read only memory such as ROM or FLASH. In one embodiment, the processor executes programming instructions stored in memory. The memory may be a separate component from the processor or may be included onboard within the processor. Alternatively, controller 146 may be constructed without using a microprocessor, e.g., using a combination of discrete analog and/or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software. Control panel 140 and other components of washing machine appliance 100 may be in communication with controller 146 via one or more signal lines or shared communication busses.
During operation of washing machine appliance 100, laundry items may be loaded into wash basket 112 through opening 122, and washing operation may be initiated through operator manipulation of input selectors 142. Wash additives may be added to washing machine appliance 100 to assist in the cleaning process. In this regard, as will be described in detail below, an additive dispensing system 200 is configured to provide one or more wash additives, such as powdered detergent, concentrated wash fluid, pretreating additive, bleach, etc. Alternatively, certain additives may be provided directly into wash tub 110, e.g., by pouring through opening 122 or through another suitable opening defined in top panel 120.
Water may be added to additive dispensing system 200 to mix with wash additives to create a wash fluid that may be dispensed into wash tub 110 and wash basket 112. In this regard, as described in detail below, one or more valves can be controlled by washing machine appliance 100, e.g., at controller 146, to provide for filling wash basket 112 to the appropriate level for the amount of articles being washed and/or rinsed. By way of example for a wash mode, once wash basket 112 is properly filled with fluid, the contents of wash basket 112 can be agitated (e.g., with an impeller as discussed previously) for washing of laundry items in wash basket 112.
After the agitation phase of the wash cycle is completed, wash basket 112 can be drained. Laundry articles can then be rinsed by again adding fluid to wash basket 112 depending on the specifics of the cleaning cycle selected by a user. The impeller may again provide agitation within wash basket 112. One or more spin cycles also may be used. In particular, a spin cycle may be applied after the wash cycle and/or after the rinse cycle to wring wash fluid from the articles being washed. During a spin cycle, wash basket 112 is rotated at relatively high speeds. After articles disposed in wash basket 112 are cleaned and/or washed, the user can remove the articles from wash basket 112, e.g., by reaching into wash basket 112 through opening 122.
Referring now to
Additive dispensing system 200 may be mounted within cabinet 102 using a plurality of mounting features or mechanical fasteners (not shown). Additionally or alternatively, adhesive(s), snap-fit mechanisms, interference-fit mechanisms, or any suitable combination thereof may secure additive dispensing system 200 to cabinet 102. One skilled in the art will appreciate that additive dispensing system 200 may be mounted in other locations and use other mounting means according to alternative embodiments.
As illustrated, additive dispensing system 200 generally includes a bulk storage tank 202 and a dispenser box 204. More specifically, bulk storage tank 202 may be positioned under top panel 120 and defines an additive reservoir 206 for receiving and storing wash additive 208. As will be described in detail below, additive dispensing system 200 may include features for drawing wash additive 208 from additive reservoir 206 and mixing it with water prior to directing the mixture into wash tub 110 to facilitate a cleaning operation.
According to the illustrated embodiment, additive reservoir 206 may contain a bulk volume of wash additive 208 (such as detergent or other suitable wash additives) such that additive reservoir 206 is sized for holding a volume of detergent sufficient for a plurality of wash cycles of washing machine appliance 100, such as no less than twenty wash cycles, no less than fifty wash cycles, etc. As a particular example, additive reservoir 206 is configured for containing wash additive 208 no less than twenty fluid ounces, no less than three-quarters of a gallon, or about one gallon. Thus, a user can avoid filling dispenser box 204 with detergent before each operation of washing machine appliance by filling additive reservoir 206 with detergent.
As discussed above, and referring now also to
Dispenser box 204 may further include a plurality of valves configured to supply hot and cold water for mixing with wash additive 208 or for dispensing directly into wash tub 110. For example, according to the illustrated embodiment, a plurality of apertures 212 (
Water inlets may be placed in fluid communication with each of the water regulating valves 214. More specifically, as shown in
Controller 146 may selectively open and close water valves 214 to allow water to flow from hot water inlet 216 and from cold water inlet 218 through one or more apertures 212. For example, water regulating valves 214 may be independently operated to provide hot water, cold water, or mixed water to any suitable compartment or conduit within dispenser box 204 or directly into wash tub 110. Specifically, in order to dispense water and/or wash fluid at the desired temperature, hot and cold water may be selectively dispensed in ratios that produce the desired water temperature, e.g., by manipulating water regulating valves 214. Controller 146 is communicatively coupled (e.g., via a wireless or wired connection) with water regulating valves 214, for example, such that water may be selectively supplied through valves 214 from hot water inlet 216 and cold water inlet 218 to provide water at a predetermined temperature based on at least one of the selected wash cycle, the soil level of the articles to be washed, and the article type.
Washing machine appliance 100 includes various features for drawing wash additive 208 from additive reservoir 206 and directing wash additive 208 into wash tub 110. For example, as best shown in
As best shown in
More particularly, as the flow of water 230 is supplied through Venturi pump 222 to wash tub 110, the flowing water creates a negative pressure within suction line 226. This negative pressure may draw in wash additive 208 from additive reservoir 206. When certain conditions exist, the amount of wash additive 208 dispensed is in proportion to the amount of time water is flowing through Venturi pump 222. However, as explained above, various factors such as additive viscosity and tank level affect how much wash additive 208 is actually entrained into the flow of water 230.
According to an exemplary embodiment, aspirator assembly 220 may further include a valve 234 operably coupled to suction line 226 to control the flow of wash additive 232 through suction line 226 when desired. For example, valve 234 may be a solenoid valve that is communicatively coupled with controller 146. Controller 146 may selectively open and close valve 234 to allow wash additive 208 to flow from additive reservoir 206 through additive suction line 226. For example, during a rinse cycle where only water is desired, valve 234 may be closed to prevent wash additive 208 from being dispensed through suction line 226. In some embodiments, valve 234 is selectively controlled based on at least one of the selected wash cycle, the soil level of the articles to be washed, and the article type. According to still other embodiments, no valve 234 is needed at all and alternative means for preventing the flow of wash additive 232 or other water regulating valves 214 may be used to provide water into wash tub 110.
As should be appreciated, Venturi pump 222 includes a converging section 240 and a diverging section 242. Converging section 240 of Venturi pump 222 is disposed upstream of diverging section 242 of Venturi pump 222 relative to the flow of water 230 through Venturi pump 222. As the flow of water 230 enters converging section 240 of Venturi pump 222, the flow of water 230 may increase in velocity and decrease in pressure. Conversely, as the flow of water 230 passes from converging section 240 of Venturi pump 222 into diverging section 242 of Venturi pump 222, the flow of water 230 may increase in pressure and decrease in velocity.
Suction line 226 may extend between an inlet 244 and an outlet 246, e.g., between additive reservoir 206 and Venturi pump 222. For example, inlet 244 of suction line 226 is disposed within additive reservoir 206, e.g., at or adjacent bottom wall of additive reservoir 206. Outlet 246 of suction line 226 is disposed at Venturi pump 222. The flow of wash additive 232 may enter suction line 226 at inlet 244 of suction line 226, flow through suction line 226 to Venturi pump 222, and enter Venturi pump 222 via outlet 246 of suction line 226.
The change in pressure for the flow of water 230 through Venturi pump 222 may assist with drawing wash additive 208 from additive reservoir 206. For example, additive reservoir 206 may be exposed to or contiguous with ambient air about washing machine appliance 100 (e.g., via reservoir inlet 132), and outlet 246 of suction line 226 may be positioned on Venturi pump 222 (e.g., converging section 240 of Venturi pump 222 or diverging section 242 of Venturi pump 222) such that a pressure of fluid at outlet 246 of suction line 226 is less than the pressure of detergent within additive reservoir 206 at inlet 244 of suction line 226. Thus, Venturi pump 222 may pump the flow of detergent 232 from additive reservoir 206 to Venturi pump 222 via suction line 226 when the flow of water 230 passes through Venturi pump 222. Within Venturi pump 222, the flow of water 230 and the flow of detergent 232 may mix and a mixture of water and detergent exits Venturi pump 222 and flows into wash tub 110. In such a manner, detergent from additive reservoir 206 may be dispensed in to wash tub 110.
As explained above, additive dispensing assembly 200 is generally configured for operating water regulating valve 214 based at least in part on an additive level 250 of wash additive 208 within additive reservoir 206. Accordingly, a tank level sensor 252 may be positioned within or operably coupled with additive reservoir 206 for detecting a level of wash additive 208 stored therein. Specifically, as illustrated in
Tank level sensor 252 may be any suitable sensor for providing information related to the level or amount of wash additive 208 stored within additive reservoir. For example, tank level sensor 252 may provide level information in terms of a height of the wash additive 208, a percentage of additive reservoir 206 filled, a volume measurement, or any other suitable data indicative of the level of wash additive 208. According to exemplary embodiments, tank level sensor 252 may be a float sensor, a magneto-inductive level sensor, a capacitive sensor, an optical sensor, an acoustic sensor, or any other suitable type, configuration, or number of level sensors.
In addition, tank level sensor 252 may be configured for measuring the additive level 250 according to any suitable tolerances, according to predetermined threshold levels, or in any other suitable manner. For example, according to an exemplary embodiment, tank level sensor 252 may be a conductivity sensor that determines whether the additive level 250 is below a predetermined threshold level or above that threshold, and returns a corresponding “low” or “high” level value. The predetermined threshold level may be associated with a point at which the additive dispense rate may be or should be approximated as a different value. For example, controller 146 may be configured for assuming a fixed lower additive dispense rate when the tank level is “low” and a fixed higher additive dispense rate when the additive level 250 is “high.”
According to alternative embodiments, tank level sensor 252 may be a magneto-inductive sensor that provides an extremely precise additive level 250 or volume. This volume or level may be associated with a specific additive dispense rate which may be stored in a table within controller 146 or accessible by controller 146. In this manner, controller 146 may obtain the additive level 250 within the additive reservoir 206, obtain the additive dispense rate corresponding to that additive level 250 from the lookup table, and use that additive dispense rate to accurately dispense water and the target volume of wash additive. Other methods of obtaining tank levels and correlating those levels with additive dispense rates are possible and within the scope of the present subject matter.
Now that the construction and configuration of washing machine appliance 100 and additive dispensing system 200 have been presented according to an exemplary embodiment of the present subject matter, an exemplary method 300 for dispensing wash additive using an additive dispensing system is provided. Method 300 can be used for washing machine appliance 100 and additive dispensing system 200, or to operate any other suitable detergent dispensing appliance using any other suitable dispensing system. In this regard, for example, controller 146 may be configured for implementing method 300. However, it should be appreciated that the exemplary method 300 is discussed herein only to describe exemplary aspects of the present subject matter, and is not intended to be limiting.
As shown in
Notably, the viscosity of wash additive 208 may also affect the additive dispense rate from additive reservoir 206. Thus, according to an exemplary embodiment, step 330 includes determining a viscosity factor of the wash additive. For example, the viscosity factor of the wash additive may be defined as a ratio of an actual viscosity of wash additive 208 over an average viscosity of a standard wash additive which may be preprogrammed into controller 146. Thus, for example, if additive dispensing system 200 is configured for dispensing wash additive 208 having a viscosity of 500 centistokes, but the viscosity of the wash additive 208 actually dispensed from additive reservoir 206 is 600 centistokes, the viscosity factor may be 1.2. However, it should be appreciated that according to alternative embodiments, any suitable correction factor or manner of adjusting the viscosity of the wash additive to achieve the desired conversion or compensation is possible and within scope of the present subject matter.
According to an exemplary embodiment, determining the additive dispense rate may include obtaining the additive dispense rate from a lookup table or database that correlates the level of wash additive and/or the viscosity of the wash additive to the additive dispense rate. In this regard, for example, controller 146 may store a lookup table which contains predetermined additive dispense rates based at least in part on the level of wash additive or its viscosity (or viscosity factor). Thus, controller 146, after obtaining the level of wash additive at step 310, may input that additive level into the lookup table and obtain an approximate additive dispense rate which may then be used to regulate water valve 214 to dispense the target volume of wash additive 208.
Notably, the viscosity of the wash additive 208 loaded or to be loaded within additive reservoir 206 of washing machine appliance 100 may be determined in various exemplary ways. In this regard, controller 146 may receive a user input regarding the actual viscosity or a viscosity factor of a wash additive when it is added to additive reservoir 206. For instance, a user may directly enter or select the viscosity of the one or more wash additives to be loaded or loaded in washing machine appliance 100 by interfacing with input selectors 142 and/or display 144 of control panel 140. For instance, a user may utilize input selectors 142 to enter four hundred centistokes (400 cSt) as the viscosity of one of the wash additives contained within additive reservoir 206 of additive dispensing system 200. As another example, a user may provide a voice command to a microphone (not shown) of washing machine appliance 100 or by interfacing with an application or webpage of a user device (not shown) that is communicatively coupled (e.g., by a wireless or wired connection) with the washing machine appliance 100.
As yet another example, in some exemplary embodiments, washing machine appliance 100 may include a scanning device (not shown) that may be used to scan a visual code (e.g., Quick Response (QR) code, Universal Product Code (UPC), other types of bar codes, etc.) of a container in which the wash additive is stowed. Thus, a user may present the container proximate the scanning device so that the scanning device may read the visual code. Based on the visual code, controller 146 can determine the viscosity of the wash additive, e.g., by using a lookup table. As a further example, in some embodiments, washing machine appliance 100 includes an image capture device (not shown), such as a camera, that is configured to capture an image of the container (e.g., including viscosity values) in which the wash additive loaded or to be loaded within washing machine appliance 100 is stored.
In some instances, the input indicative of the viscosity of the wash additive may be the actual viscosity of the wash additive, e.g., the input might be five hundred centistokes (500 cST). In other instances, the input indicative of the viscosity of the wash additive may be information indicative of the viscosity but not the actual viscosity value of the wash additive (e.g., the viscosity factor). For example, the input may include the brand type and wash additive type of the wash additive loaded or to be loaded in the additive reservoir 206 of washing machine appliance 100, and based on these inputs, the viscosity of the wash additive may be determined.
In addition, if the viscosity factor is known, the additive dispense rate may be adjusted accordingly. Specifically, step 340 includes determining a corrected dispense rate based at least in part on the additive dispense rate and the viscosity factor. For example, according to an exemplary embodiment, the additive dispense rate may be multiplied or divided by the viscosity factor in order to obtain a new additive dispense rate that more accurately predicts the volume of wash additive 208 which will be dispensed for a fixed dispense duration as controlled by water regulating valve 214. According to another embodiment, the lookup table may be pre-populated with a precise additive dispense rate empirically determined as a function of both additive level and additive viscosity. It should be appreciated that the methods of determining the additive dispense rate as described herein are only exemplary and not intended to limit the scope of his present subject matter in any manner.
Step 350 includes selectively dispensing a flow of water through Venturi pump based at least in part on the corrected dispense rate to dispense a target volume of the wash additive. In this regard, controller 146 may open water regulating valve 214 for a dispense duration sufficient to draw a target volume of wash additive 208 through Venturi pump 222 and into wash tub 110. According to exemplary embodiments, this dispensing process may include determining a dispense duration corresponding to an amount of time the water regulating valve should be opened to dispense the target volume of wash additive by opening the water regulating valve for that dispense duration. In addition, for example, determining the dispense duration may include dividing the target volume (e.g., in ounces) by the additive dispense rate (e.g., in ounces per second).
Notably, when additive dispensing assembly 200 is able to detect the additive level 250 precisely, compensation for the additive dispense rate may be implemented during subsequent washing cycles. For example, controller 146 may be programmed with specific parameters which may be adjusted based on collected data from prior cycles, lookup table may be modified to adjust the additive dispense rates as a function of wash additive level or viscosity, etc. Specifically, for example, tank level sensor 252 may be configured for measuring a pre-dispense additive level and a post-dispense additive level. Controller 146 may be configured for comparing the post-dispense additive level to the pre-dispense additive level and adjusting the viscosity factor of the wash additive for a subsequent wash cycle if the dispensed volume is different than the target volume. In this regard, for example, by subtracting the post-dispense additive level from the pre-dispense additive level, the actual volume of dispensed wash additive 208 may be obtained or approximated. If that volume does not match the target volume of wash additive 208, controller 146 may implement corrective action.
According still other embodiments, controller 146 may be configured for generating an alert if the comparison of the post-dispense additive level in the pre-dispense additive level shows a difference between the dispensed volume and the target volume after adjusting the viscosity factor. In this regard, controller 146 may include limits on how much adjustment may be made to the viscosity factor or the additive dispense rate before a system fault is generated. Once those limits are reached, a user may be notified, e.g., via display 144, that a system error or machine fault is occurring and needs to be corrected.
Referring now to
As shown, at step 402, controller 146 may determine whether tank level sensor 252 is a single level sensor or a multi-level sensor. If tank level sensor 252 is a single level sensor, controller 146 may then determine whether the viscosity of wash additive 208 is known at step 404. At step 406, tank level sensor 252 may be used to determine whether additive level 250 is greater than a predetermined threshold (e.g., TLow). If the additive level 250 is above the predetermined threshold, at step 408, controller 146 may assign the additive dispense rate a first value (e.g., a relatively high dispense rate X). By contrast, if the additive level 250 is below the predetermined threshold, controller 146 may assign the additive dispense rate a second value (e.g., a relatively low dispense rate Y). In addition, if the viscosity was determined to be known at step 404, a viscosity factor may be determined and the additive dispense rate may be adjusted, e.g., by multiplying the assigned rate of X or Y times the viscosity factor. According still other embodiments, the viscosity factor may itself depend in part on the level of additive within the tank.
If a multilevel sensor is used, controller 146 may proceed through similar steps but may further implement a correction process to adjust the additive dispense rate for subsequent processes based on the measured feedback related to the amount of dispensed detergent. In this regard, for example, at step 410, the level of wash additive 250 before and after a dispense procedure may be compared to determine the amount of additive actually dispensed from additive reservoir 206. If the amount of wash additive 208 actually dispensed does not match the target volume, controller 146 may make subsequent adjustments to the additive dispense rate or viscosity factors to compensate for such errors. For example, operating parameters of water regulating valves 214 may be adjusted, lookup table values may be modified, or other operating parameters of additive dispensing assembly 200 may be changed to achieve the target dispense volume on subsequent operating cycles. It should be appreciated that variations and modifications to method 300 and flow diagram 400 may be made while remaining within the scope of the present subject matter.
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.
