This invention belongs to the mechanical engineering field, more specifically of the electromechanical devices, commonly known as home appliances, especially applied to washing machines and the like, exactly a washing method and recirculation control associated to a washing machine provided with washing water recirculation with controlled flow.
The washing machine is a very popular home appliance used to automatically clean clothes. It uses water as its main element. It basically consists of a reservoir which is filled with water, on which the mechanical system shakes the pieces of clothing to be washed. The contemporary machines are manufactured as two basic models, front loading or top loading. The top loading machines receive the clothes in a vertically mounted cylinder, with a central agitator and a top cover. The front loading machines have a horizontally mounted cylinder, with no central agitators, but with a watertight door and with a sight glass.
Both models have the capacity to automatically wash, propelled by an electric motor, conducting washing, rinsing and centrifugation runs. Currently, the use of electronic components replaces complex mechanical systems previously used to control the washing. They control, for example, the water level, one of the main functionalities of washing machines in the current art.
The control by means of electromechanical pressostates, which are devices used to perceive pressures or pressure differences and which, in the case of washing machines, can be translated by differences in the liquids level, is conducted by reading the level indicated by the pressure generated by a water column, which forces a diaphragm, thus activating an electric contact in a single determined point, with the disadvantage of not being able to identify the manometric height and present a continuous reading.
In its turn, the electronic pressostate forwards point-to-point information on the water column height by means of a transducer which varies the output voltage or current according to the pressure applied in the input, allowing a more precise control, admitting, in the most modern machines, the water input control.
The water level control in washing machines is also widely diffused, defining the water volume to be used in washing, upon the user's choice or a previously defined configuration for the equipment, based on a sensor, which is commonly the pressostate, which receives the pressure exerted by the water volume.
Another important event, besides the level control, among the other functionalities introduced in washing machines is recirculation.
Water recirculation is a common feature in washing machines, which is generally intended to homogenize cleaning agents and water, besides increasing the washing efficiency and collecting lints which are released from the clothes and which may affect the equipment performance. In addition, it can minimize the amount of water used for washing through water circulation optimization inside the equipment in certain steps of the washing run.
In order to improve water recirculation during the washing process, perforated baskets were developed, for which the number and size of the holes are dimensioned in order to decrease the total drainage area, thus decreasing the liquid flow from the basket to the tub, causing a delay in the process of balancing the manometric heights upon water recirculation, allowing the accumulation of a decreased amount of liquid in the tub, enabling a lower total water volume to be used in the washing process.
Despite of the recirculation advent, problems related to this functionality can be found as, for example, the excess of foam and high noise level. These problems are generated by air-water mixture, caused by the lack of water input flow control in the basket compared with the output flow from the basket to the tub, in addition to causing a non-uniform flow of the input of liquids into the basket. Without control, water drainage is not uniform when air and water are mixed in the bottom of the tank. This flow range can be significantly decrease when a controllable pump is used.
Currently, due to the mixture of air and water which occurs when the washing machine tub is empty, the use of common detergent generates a lot of foam, thus preventing a complete washing with this type of product from occurring.
Canadian Patent 1112889, according to FIG. 10, describes a washing machine which recirculates water or rinsing water. Its recirculation water input is intended to fully empty the tub, thus generating foam and noise during its operation. The remaining liquid is located in a recess of the tub, forming a pool, in order to prevent the pressostate from indicating that the tub is empty.
Document WO053042, according to FIG. 8, shows a washing machine provided with water recirculation, with the objective to empty the tub during recirculation, however, due to the lack of pump control, it does not maintain a minimum liquid level, producing foam and noise.
Document EP1783264, according to FIG. 9, reports a washing machine equipped with recirculation and a variable speed pump, however, the water level between the tub and the basket remains the same and does not save water
Invention ES8604326 in the public domain, describes the recirculation process, very common in a washing machine, with recirculation controlled by two pressostates and level control elements calibrated for higher and lower level.
Document EP0278461 in public domain, describes the discharge and recirculation flow control process of washing machines based on two pressure sensors adapted to determine the minimum and maximum liquid levels present in the referred machine.
This disclosure describes a washing machine provided with recirculation with controlled flow. It further presents a washing liquid level control method, associated with the referred machine, providing economy of resources such as water and cleaning products, guaranteeing an effective washing of clothing and similar articles, associated with lower foam formation and generation of noise during the washing process, thus improving the operation of the equipment, besides having the other recirculation and level control functionalities comprised in the current state of the art. Thus, it is evident that all these characteristics make the product free from the inconveniences found in the current state of the art, as previously mentioned.
It has a pool, consisting an a small internal reservoir formed by a recess in the tub, which guarantees the maintenance of a minimum liquid level by a recirculation pump flow control, thus avoiding the formation of foam by the air-water mixture in the mentioned pump, and as a result, reducing the level of noise during the operation.
The present disclosure provides an objective to present a method and a washing machine with the function of recirculating liquids from the bottom of the tub to the upper part of the basket which contains the clothes to be washed, in order to use a lower amount of water and increase the efficiency of the washing process, associated with an innovative method to adjust the washing and rinsing liquid level in the washing tub during the washing of clothing and similar articles, also allowing to minimize the noise and generation of foam.
The controlled recirculation described herein is an evolution of the existing techniques. In this concept, instead of using a two-state pump (turned-off or nominal speed), the disclosure proposes a pump working method intended to vary its speed and, consequently, its flow.
An aspect of the disclosure is to present a control intended to improve the recirculation concept, besides magnifying its application.
The use of a controllable pump and of a level reader allows the development of a method which is able to close a control loop on which it is possible to adjust a flow so that the system contains a small amount of water in the bottom of the machine; however, an amount which is large enough to prevent the mixture of air with water from occurring in the pump. This decreases the amount of generated foam, allowing the user to use common detergent.
In addition, considering that the traditional drainage pumps produce a lot of noise being at nominal speed and with little water in the bottom of the tank, the use of the machine and the proposed method allows decreased noise through minimizing the water-air mixture.
This invention comprises a washing machine having a recirculation and a washing liquid level control method.
The referred machine, according to
For the operation of the washing machine, the level sensor (5) reads the water column height in the tub (2), sends this information to the control circuit which processes the information and sends a signal to the two-way pump motor (7) so that it operates in the recirculation direction and ranges its speed, thus changing the water flow in order to maintain a minimum liquid level in the tub's (2) pool (6) in order to avoid cavitations in the pump (7) thus making the process less noisy and with decreased foam formation.
To better understand the invention shown here, the analysis of the attached figures is required.
During the entire process, the water level is monitored by the electronic circuit by means of signals originated by the level sensor (5).
Once the programmed washing level is reached, the washing operation is started with the mechanical movement of the agitation elements (agitator, propeller or basket (3)). In this step, the objective is to maintain the highest liquid level inside the perforated basket (3) and the lowest level inside the tub (2), without allowing the pool (6) from being empty, as it can be noted in
Following the washing step, the drainage step is started according to
Following the drainage step (which does not necessarily imply the basket being completely empty), centrifugation is started, as shown in
The proposed method uses a closed loop system as described in
Despite of the internal oscillations occurring during washing (agitation, for example), the method is sufficiently precise to work in order to absorb such variations.
The present invention further minimizes the water flow variations from the recirculation hose (9) to the basket (3) input due to the slight attenuation of the control method, once it allows a more uniform flow of liquid.
This invention is not limited to the representations commented or illustrated here, and should be understood in its wide scope. A number of changes and other representations of the invention will come to mind of those skilled in the art, with the benefit of the teaching presented in the previous descriptions and attached drawings. In addition, it should be understood that the invention is not limited to the specific disclosed form, and that change and other forms are understood as included within the scope of the attached claims. Although specific terms are used herein, they are used only as a generic and descriptive form and should not be construed as limiting.
Number | Date | Country | Kind |
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0905459 | Dec 2009 | BR | national |
Number | Name | Date | Kind |
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7703306 | Shaffer | Apr 2010 | B2 |
20060000030 | Shaffer | Jan 2006 | A1 |
Number | Date | Country |
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1112889 | Nov 1981 | CA |
0278461 AL | Aug 1988 | EP |
1783264 | Sep 2007 | EP |
2267211 | Dec 2010 | EP |
8604326 | Dec 1983 | ES |
Number | Date | Country | |
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20110138543 A1 | Jun 2011 | US |