Patent Application
20070084000
1. Field of the Invention
This invention concerns improved methods for treating clothing articles with chemical solutions using an automatic washer.
2. Description of the Art
In order to improve the cleaning of clothing articles in automatic washers, consumers routinely apply cleaning chemicals such as detergents, bleaches, fabric softeners and cleaning enhancing chemicals to clothing articles before or after they are placed into automatic washers. Manufactures of automatic washers have attempted to improve automatic washing machine convenience and clothing cleaning performance by incorporating clothing pretreatment steps into automatic washer processes in order to eliminate the need for consumers to manually pretreat clothing articles.
Stain treatment processes based on spin and spray treatment of fabrics during the wash cycle are known. There are a number of commercially available automatic washers that are capable of pretreating clothing with cleaning chemicals. In general, such automatic washers attempt to saturate the fabric with a highly concentrated detergent solution in order to enhance the chemical removal of stains. This concentrated solution is obtained by combining a detergent with a smaller volume of water than the regular is used during wash process.
A technical hurdle that must be managed when pretreating fabrics with concentrated detergent solution is the potential risk of “suds lock”. U.S. Pat. Nos. 5,507,053 and 5,219,270 disclose automatic washers that include stain pretreatment apparatuses or methods. Methods for dealing with suds lock issues caused by chemical pretreatment step are disclosed, for example, in U.S. Pat. Nos. 6,591,439, 6,584,811, 6,393,872, 6,269,666, 4,784,666 and 4,987,627. The specifications of each of these patents are incorporated herein by reference.
Despite the variety of automatic washer cleaning chemical treatment methods and apparatuses currently available, there remains a need for automatic washers that include features and that operate in a manner that improve the cleanability of clothing and textiles.
One aspect of this invention are methods for laundering a textile wash load in a washing apparatus comprising the steps of: loading a textile wash load into a wash basket of the automatic washing apparatus wherein the wash basket is surrounded by a stationary wash tub; introducing a volume of chemical solution into the wash tub; rotating the washer basked relative to the stationary wash tub at a low spin speed; applying at least a portion of the concentrated chemical solution to the textile wash load while the wash basket in rotating at a low spin speed; and rotating the wash tub at a high spin speed.
Another aspect of this invention are methods for laundering a textile wash load in an automatic washing apparatus comprising the steps of: (a) loading a textile wash load into a wash basket of the automatic washing apparatus wherein the wash basket is surrounded by a stationary wash tub; (b) introducing a chemical into the wash tub and introducing water into the wash tub to form a concentrated chemical solution having a measurable level; (c) rotating the wash basket relative to the stationary wash tub at speed that applies less than 1 GPa centrifugal force on the textile wash load; (d) applying at least a portion of the concentrated chemical solution to the textile wash load while the wash basket in rotating at a low spin speed; (e) halting the application of the concentrated chemical solution to the textile wash load; (f) rotating the wash basket at a spin speed that applies greater than 1 GPa centrifugal force to the textile wash load; (g) halting the rotation of the wash basket at a speed that applies greater than 1 GPa centrifugal force to the textile wash load; (h) introducing water into the wash tub and admixing the water with the concentrated chemical solution until there is a measurable level of concentrated chemical solution in the wash tub; and (i) repeating steps c-e at least once.
In still another aspect, this invention includes methods for laundering a textile wash load in a washing apparatus comprising the steps of: (a) loading a textile wash load into a wash basket of the washing apparatus wherein the wash basket is surrounded by a stationary wash tub; (b) introducing a predetermined volume of concentrated detergent solution into the stationary wash tub without wetting the textile wash load; (c) rotating the wash basket relative to the stationary wash tub at a low spin speed for a predetermined length of time; (d) applying a volume of the concentrated detergent solution to the textile wash load while the wash basket is rotating at a low spin speed by withdrawing concentrated detergent solution from the wash tub and directing the withdrawn concentrated detergent solution into the wash basket and into contact with the textile wash load; (e) interrupting application step d and accelerating the wash basket to a high spin speed; and (f) repeating steps c-e a predetermined number of times.
The present invention is directed generally to improved methods for cleaning textile wash loads in automatic washers. The methods use a combination of low and high wash basket spin speeds in order to saturate a textile wash load with a chemical solution to enhance textile wash load cleanability. The unique processing embodiments of this invention minimize the liquid volume required to saturate a textile wash load at a given spin speed and they may also minimize suds lock and splash risk. The use of a combination of low and high wash basket spin speeds in the methods of this invention enables the methods to be practiced using washing machines including relatively common hardware. Moreover, there is no need for the washing machine that it is capable of performing the methods of the invention to include splash shields or a sump. Nor is there is a need for concise system control of low water level in the wash tub in washing machines that practice the methods of this invention.
The present invention relates to methods for treating textiles with chemical solutions in an automatic washing machine in order to improve the washing machine performance—i.e., textile cleanability. In the methods of this invention, a chemical solution is intermittently applied to textiles loaded in a washing machine while the washing machine wash basket rotates alternatively at low and high spin speeds. Thereafter, the chemical solution may optionally remain in contact with textile wash load for a period of time before commencing or recommencing standard textile washing steps.
A washing machine 10 is generally shown in
A sump hose 40 is fluidly connected to a sump (not shown) contained in a lower portion of tub 12 for providing a fluid recirculating source. Recirculating fluid exits the sump via recirculating spray nozzle hose 48 which is fluidly connected to recirculating spray nozzle 32. An air dome 50 having a deepfill pressure sensor or transducer provides a pressure signal indicating when a minimum detectable amount of liquid is present in wash tub 12.
As described herein, a pressure sensor may be a pressure switch having predetermined pressure levels that, within certain limits, will provide one or more signals to control 22 that a certain pressure has been achieved. Depending on the presence or absence of such signals, the control will receive and store or process such information, as is well known. Alternatively, a transducer may be used to sense pressure and provide a signal of varying frequency or voltage to control 22 indicating the pressure levels detected.
The process of this invention will be discussed in the context of its operation in a vertical axis automatic washing machine as shown in several of the figures. However, the processes of this invention are equally applicable to horizontal or tilted axis washing machines. Moreover, the processes of this invention may be practiced in a variety of machines which may include, for example, different motor and transmission arrangements, pumps, recirculation arrangements, agitators, impellers, wash baskets, wash tubs, or controls so long as the arrangements are capable of accomplishing the processes of this invention.
Upon opening one or both of valves 17 and 19, fresh water is selectably provided to a series of dispenser valves via feed line 60. Valve 62 selectably directs fresh water into detergent dispenser 63. When fresh water is directed to detergent dispenser 63, it flows through dispenser 63 and into wash tub 12 thereby bypassing wash basket 28. Valve 64 selectably provides fresh water to bleach dispenser 65, and valve 66 selectably provides fresh water to softening agent dispenser 67.
The washing machine of
Control 22 receives a static pressure signal from deepfill transducer dome 50 via lines 52 for signaling the level of wash liquid within wash tub 12 including signaling when a minimum detectable liquid level is reached, however the invention disclosed herein may be practiced using a liquid detection device other than a deepfill pressure dome. Control 22 is further operable to receive input signals via lines 49, including signals from valves 21, 62, 64 and 66 providing on and off times for these valves.
The term “chemical solution” is used herein to refer to any type of chemical cleaning solutions that are useful in cleaning textiles in automatic washing machines. Chemical solutions include, but are not limited to detergents, textile prewash solutions, bleaches, fabric softeners and any other known or future discovered chemicals that are useful in enhancing the cleaning of soiled textiles. Chemical solutions further include chemicals that are supplied in liquid form and chemicals that are supplied in dried form that are subsequently liquefied, suspended or dissolved in a liquid such as water.
The term “concentrated chemical solution” as used herein refers to chemical solutions, such as those described above, in undiluted form as well as to the chemical solutions that are diluted with diluents such as water. The term “concentrated chemical solutions” alternatively refers to chemical solutions that are used in concentrations that are greater than they would normally be used in standard textile wash processes.
When the chemical solution is a detergent, the concentrated detergent solution will typically include a mixture of water and detergent in which the detergent is present in an amount ranging from about 0.5% to about 4% or more by weight. The amount of detergent present in a concentrated detergent solution may be greater than about 4 wt %.
In step 120 of
The concentrated chemical solution may be applied to the textile wash load by any means known in the art for applying a liquid to textiles loaded in a wash basket. In one method, the concentrated chemical solution is directed by pump 23 to nozzles such as nozzle 32 of
Wash basket 28 is preferably spun at a low spin speed for a predetermined period of time in step 120. The term “low spin speed” refers to a wash basket spin speed at which a chemical solution can be applied to the textile wash load such that there is essentially no axial extraction of the chemical solution from the textile wash load. In yet another embodiment, the low spin speed is a speed that applies less than one gravity of centrifugal force (less than 1 GPa) to the textile wash load.
In step 120, wash basket 28 is rotated at a low spin speed for a period of time. The period of time is generally a predetermined period of time that is set during the development of the washing machine and that is integral to the wash machine control program. In one embodiment of this invention, the predetermined period of time may change depending upon the designated textile load size (e.g. small or large), load type (e.g. delicates or cottons) and/or wash cycle designated by the washing machine user. The predetermined period of time during which wash basket 28 is a low spin speed and step 120 will generally range from a minimum of about 1 to a maximum of about 60 seconds with an alternative and narrower range of time from about 1 to about 20 seconds. The predetermined period of time can be greater or less than the values given above depending upon factors such as recirculation pump flow rate and the ability of pressure transducer to detect low water level.
In step 120 of
In step 130 of
The predetermined period of time during which wash basket 28 spins at a high spin speed is generally the time necessary to achieve one or more of the goals of the high spin speed mentioned above. In general, the predetermined time during which wash basket 28 spins at a high spin speed will range from about 1 to about 180 seconds or in the alternative in a range of time ranging from about 5 to about 30 seconds. Once the predetermined period of time is reached, the wash basket spin speed is reduced once again to a low spin speed in step 140.
Step 150 of
If the process does include an endpoint testing step 150, then the textile wash load is evaluated for whether or not the endpoint has been achieved before selecting the subsequent process step. The endpoint can be evaluated by a variety of methods. For example, the endpoint can be reached when there is no more available concentrated detergent solution to apply to the textile wash load. Alternatively, the endpoint can be evaluated by measuring process parameters such as wash basket motor load, pump loads, and so forth to correlate the operational parameters with the degree of saturation of textile wash load. In
In some instances, the textile wash load may not be saturated with a chemical solution after the predetermined number of iterations are complete. Or, in the alternative, none or not enough of the chemical solution may remain in wash tub 28 to be applied to the textile wash load even though the predetermined number of iterations of step 160 has not been met. In second and subsequent iterations of the low spin speed high spin speed steps 120, 130 and 140, water may be added into wash tub 28 in step 110 to raise the liquid level of the wash tub to at least a minimum detectable level. Once the at least minimum detectable level of solutions is reached, water addition to the wash tub is halted and the chemical solution (now diluted) is applied to the textile wash load while the wash basket is spinning at low spin speeds in application step 120 by the methods discussed above.
In one embodiment of this invention, the chemical solution is a detergent solution that is used to pretreat textiles in order to improve their cleanability during normal washing procedures. In this embodiment, once the textile wash load is tested and determined to be saturated, or once the predetermined number of iterations of steps 120, 130 and 140 are reached in step 160 of
In step 240 of
Once the predetermined exposure time duration has been reached, a predetermined volume of fresh water is introduced into the wash bucket in step 250. The predetermined volume of fresh water will be of volume that is sufficient to fill wash tub 12 with enough water so that the textile wash load can be agitated in a water filed automatic washer in a normal washing process. The pretreated textile wash load is agitated for a predetermined period of time in step 260 after which the detergent solution is rinsed from the load in step 270 to complete the pretreatment and textile wash steps.
In
In
Table 1, below, summarizes the steps of a detergent pretreatment process. Table 2, below, summarizes the steps of a concentrated bleach treatment process.
In the stain removal pretreatment process of Table 1, the manufacturer's recommended amount of powdered or liquid detergent is added to the wash tub of the automatic washer via the detergent dispenser. Warm tap water is added to the wash tub through the main wash dispenser in step 3. The steps 1-13 of Table 1 embody a concentrated detergent stain removal pretreatment process of this invention.
Table 2 summarizes the steps that occur during a concentrated bleach treatment process embodiment of this invention. The concentrated bleach treatment process is activated when the user of the automatic washing machine selects “whites” as the textile type on the control panel of an automatic washing machine. The manufacturer's recommended amount of bleach is added to the wash tub via the bleach dispenser. The concentrated bleach treatment process is performed following the main wash step in a standard washing machine.
In Table 1 and/or Table 2: “WL” refers to water level wherein a water level of 15 mm refers to a height of 15 mm above the pressure dome which is set as the minimal detectable water level by the location of the pressure transducer; “ramp” refers to the time, in milliseconds, for the wash basket to accelerate to the identified “speed” or rpm; “recirc” indicates whether or not the recirculation pump that directs fluid from the wash tub sump through the recirculation line and to a spray nozzle directed at the textile wash load is off or on; “Coast” refers to the wash basket spinning on its own momentum without mechanical or electrical assistance; “Spin ON” or “spin OFF” refers to instances where the wash basket drive motor is activated “ON” to cause the wash basket to spin or deactivated “OFF”; “timed fill” refers to a step where a timed amount of water is added to the wash tub wherein the time identified is the time that the valve allowing fresh water to enter the wash tub is open. “ATC hot” refers to hot water having a temperature that is controlled automatically by the washer by controlling the amount of fresh hot and cold tap water that is allowed to enter the wash tub; “drain ON” or “drain OFF” refers to the valve to the drain being activated “ON” to direct fluid in the recirculation line to the drain, or “OFF” to close the valve leading to the drain.
These inventions disclosed herein may be embodied in other specific forms without departing from their spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is therefore indicated by the appended claims rather than the foregoing description. All changes within the meaning and range of equivalency of the claims are to be embraced within that scope.
