Method for Introducing Detergents and Associated Washing Machine

Abstract

A method and washing machine that drives a cylindrical drum body, having openings and rotatably supported about an approximately horizontal axis in a tub, in a preferred direction of rotation, and that flows a detergent-liquid mixture in a stream onto an area of an upper quandrant of the cylindrical drum at an oblique angle against the preferred direction of rotation.

Description

The starting point of the present invention is a method for the introduction of detergents into program-controlled washing machines by a detergent-liquid mixture flowing through a preferably cylindrical drum body in which openings are provided of a washing drum supported rotatably around an at least approximately horizontal axis in a tub.

Such a method follows on from DE 43 42 627 C2 or DE 43 42 626 C2. It is able to be executed with a washing machine which features a detergent dispensing facility controllable in respect of detergent temporarily stored within it and a detergent feed line as well as a drive motor for the washing drum controllable in respect of its direction of rotation. The term detergent is used here and below as a simple generic term for all types of washing, fabric care and rinsing agents which are normally used in washing machines.

With washing machines of the type discussed here the detergent required for a washing program is deposited in a drawer of the detergent dispensing facility. To accept different types and quantities of detergents there are generally a number of compartments present in the drawer, which are flushed through during the individual washing program phases by means of a controllable water jet. The water-detergent mixture flows via a dispensing line into the tub. After the washing process the washing liquor is pumped away. To this end an outlet opening is provided at a fixed point in the tub with a flange for connecting the drain pump line.

Manufacturers of washing machines are making efforts to use the detergents employed in the washing process as effectively as possible and to avoid wastage. Wastage can arise for example by undissolved detergent getting into the drain pump line at the tub, no longer being dissolved and thus remaining ineffective for the washing process.

To counter such detergent wastage, recirculating pump systems are used in known washing machines for recirculating detergents back into the tub (e.g. DE 37 04 079 A1 and DE 35 40 741 A1). Using a recirculating pump the washing liquor is pumped away via the drain pipe from the lowest point of the tub and transported to the upper area of the tub. The washing liquor is thus circulated; the detergent is dissolved by constantly being moved in the liquor.

Another approach to countering detergent wastage consists of radically reducing the volume of liquor ineffective for the washing process. In various embodiments solutions are proposed for closing off the drain pipe to the liquor or circulation pump during the washing process. The closure mechanism prevents undissolved detergent being able to be deposited in the outlet flange and thus being lost to the washing process.

DE 100 65 404 A1 is given as an example of such a solution. In this patent it is proposed that the opening to the drain pipe be closed off by a float which is pressed against an annular projection in the drain opening of the tub. To improve the sealing effect the float is coated with rubber or with an elastic plastic. The pressure on the float is created by the column of water standing in the feed line to the return container. Arranged in the upper area of washing machine is a return container in which a column of water stands above the level of the freshly supplied detergent-water mixture and thus has the height necessary for creating the pressure acting on the float. The used liquor is pumped out of the tub via the return container.

The disadvantage shared by the two solutions described above is that the washing machines have to be equipped with expensive additional devices in order avoid or reduce detergent wastage. These additional devices add not inconsiderable costs to such washing machines. A further disadvantage of the circulation pump system described in the first instance is that additional energy has to be used during operation of the washing machine.

The object of the invention, to minimize detergent wastage, is to specify a method that can be implemented with a very small material outlay and which requires no additional energy to be expended in operating the washing machine.

Inventively the object is achieved by the features given in the characterizing part of claim 1. In addition a washing machine achieving this object for executing the method is specified in claim 6. Further advantageous embodiments of the invention are contained in the subclaims of which the features can be applied individually or in any given combination with each other or with the features of claim 1 or 6.

According to the invention, while the washing drum is being driven in a preferred direction of rotation, the detergent-liquid mixture flows in a stream against the moving drum body so that the stream hits an area of the drum body at an oblique angle, said area lying in the upper quadrant of the cylinder form of the drum. The drum is moved against the direction of flow of the introduced detergent-liquid mixture in a preferred direction of rotation. In addition there is a preferred variant in which the detergent-liquid mixture flowing downwards is kept away from the drain opening for as long as possible.

It is now evident that by this simple measure the dissolving of the detergent can be significantly improved without additional effort. An especially good effect can be achieved with the method if the surface of the washing drum is a surface which amplifies an eddy movement, especially a structured body surface. This enables the detergent-liquid mixture to be retained for a long time in the upper area as the drum rotates, i.e. away from the drain opening.

The method can be implemented with the minimum effort since it is essentially characterized by a pure software solution. No additional modules or parts to be fitted are necessary for practical implementation of the method. The method can be used for washing machines in which the detergent-liquid mixture is not directed centrally from above onto the drum body and can be retrofitted by reprogramming or replacing the program chip.

In an embodiment of the invention the detergent-liquid mixture flows over almost the entire depth of the drum distributed onto the drum body. The inflowing liquid flows more evenly over the drum body, promoting the dissolving of the detergent. The even distribution also has the effect of enabling more mixture to reach the inside of the drum through the openings in the drum body even during initial feeding. The washing is thus wetted more quickly. The wetting of the washing can be further improved by the openings in the drum body having a greater admittance capability in the preferred direction of rotation.

The amount of liquid hitting the washing via the openings in the drum body during the feeding phase is—within limits—able to be controlled by regulating the speed of rotation of the drum. The method in accordance with the invention thus offers an additional option for designing the washing programs.

The inventive method and its associated exemplary embodiments are described with reference to drawings listed below. The figures show

FIG. 1 a washing machine in a perspective view and

FIG. 2 a detailed view of the upper area of the drum body.

FIG. 1 shows a perspective view of a washing machine 1 from the front. To simplify the diagram it contains only the components of significance for the function of the inventive method.

The tub 3 and the washing drum 4 able to be rotated therein around a horizontal axis 14 have a loading opening which can be closed by means of a door which has been removed in this diagram. Arranged in the upper housing area are the control panel 1 and also the detergent dispensing facility. The detergent required is deposited in its drawer 2 which can be pulled out horizontally in a forwards direction. To accept different detergents the drawer 2 is subdivided into a number of compartments which can be flushed out under program control using fresh water fed from an external water supply system.

The floor of the dispensing facility merges with an outlet flange for the detergent feed line 7. In the drawing the direction of flow of the detergent-liquid mixture is indicated by arrows 6. To pump out the washing water a drain opening 10 is provided at the lowest point of the tub 3, which is linked to the drain pump 11 via a connected line.

The detergent-liquid mixture is introduced distributed over the width of the drum body 13 (FIG. 2) via a liquid distributor 5 which is attached in parallel to the axis of rotation of the drum 14 centrally to the outside of the tub 3 and has a series of through openings. At its two edges towards the rear panel and towards the front panel the drum surface 13 features raised edge bars resulting from manufacturing (not shown) which prevent the incoming detergent-liquid mixture from flowing away over the sides. The stream of liquid 12 hits the drum body 13 of the washing drum 4 from above at an oblique angle. The movement of the drum body 13, as a result of the preferred direction of rotation 8 of the washing drum 4 is directed against the direction of flow 12 of the incoming detergent-liquid mixture. The detergent-liquid mixture is introduced into an area of the tub within the upper quadrant of the drum cylinder.

This constructive measure and the flow caused by the rotation of the drum against the direction of movement of the drum body and the fact that the mixture is kept away from the drain opening helps the detergent to dissolve.

In the exemplary embodiment the throughflow openings 9 in the drum body 13 are embodied by gill-like raised sections in the form of a half cone (see FIG. 2). This form on the one hand causes a delay in the draining of the detergent-liquid mixture from the drum body 13. On the other hand the openings 9 made in the direction of rotation 8 of the drum 4 cause liquid to be directed into the inside of the drum to an increased extent. The wetting-through of the washing is speeded up. Other, if necessary additional raised structures in the drum surface 13, preferably those which cause a greatly eddied flow of the detergent-liquid mixture, can support the length of time for which the mixture remains on the drum surface 13 and its entry into the washing drum 4 and contribute to the detergent being well dissolved at the correct time, before the mixture reaches the floor of the tub and the drain opening.

Claims

1-8. (canceled)

9. A method for introducing detergents in program-controlled washing machines, the method comprising:

driving a cylindrical drum body, having openings and rotatably supported about an approximately horizontal axis in a tub, in a preferred direction of rotation; and

flowing a detergent-liquid mixture in a stream onto an area of an upper quandrant of the cylindrical drum at an oblique angle against the preferred direction of rotation.

10. The method of claim 9, wherein the preferred direction of rotation results in the detergent-liquid mixture falling downwards in a flow pointing away from a drain opening in the tub.

11. The method of claim 9, wherein the preferred direction of rotation results in the detergent-liquid mixture entering more quickly through the openings in the drum body or is expelled through the openings more effectively than in an opposite direction of rotation to the preferred direction.

12. The method of claim 9, wherein the flowing comprises distributing the flowing over the width of the drum body into the tub according to the depth of the washing drum.

13. The method of claim 9, wherein driving the cylindrical drum body comprises controlling a speed of rotation of the drum body.

14. A washing machine comprising:

a detergent dispenser controllable for temporarily storing an output of detergent;

a detergent feed line extending from an area of a tub and for directing a stream of detergent-liquid mixture falling from a mouth of the detergent feed line onto a surface of a washing drum from above at an oblique angle; and

a drive motor for controlling a direction of rotation of the washing drum and for rotating the washing drum in a preferred direction of rotation against the stream.

15. The washing machine of claim 14, wherein the washing drum comprises openings in a drum surface which in each case have an admittance or an expulsion effect which are greater on rotation of the washing drum in the preferred direction of rotation than they are during rotation in the direction opposite to the preferred direction of rotation.

16. The washing machine of claim 14, wherein the drum surface comprises structures which delay an unhindered draining of the detergent-liquid mixture.