EP0437735B1 - Drum washing machine - Google Patents

Abstract

The invention relates to a drum washing machine having a tub (1) for receiving the washing liquor, a fresh-water supply (6), a washing-agent feed device (7) and a delivery line (5) to the tub, a venting device (11) for the tub and a device for preventing the flow-off of the detergent during the washing operation. According to the invention, the drum washing machine is equipped with a device (12) for generating compressed air. To empty the tub, the compressed air is pumped into this via a delivery line (11). <IMAGE>

Description

The invention relates to a drum washing machine with a tub for receiving the washing liquor, with a fresh water supply, a detergent dispenser and a feed line to the tub, with a venting device for the tub and with a device for preventing the washing liquor outflow during the washing process.

When washing in drum washing machines, it is customary to empty the used washing and rinsing water from the tub into the public drain system after each wash. To do this, use a drain pump or gravity, the water draining through a switchable solenoid valve.

The conventional method, in which the tub is emptied by a tub pump, has numerous disadvantages. The suction behavior of the pump is disturbed by the mostly unavoidable foam formation. This leads to delays in the emptying process and disturbing pumping and slurping noises. In addition, drain pumps or solenoid valves are not inconsiderable cost factors in the production of washing machines.

In a washing machine (DE - U - 80 08 161), it is known to empty the washing liquid into an intermediate store via a drain opening of the suds container. If the suds container is empty, a valve to the suds container is closed and the washing liquid can be conveyed from the intermediate store into the drain by means of compressed air.

With the measure described here arises for the Buffer storage requires more space within the washing machine. The required valves and the buffer store lead to a complicated and expensive drain system. Service work is also made more difficult and there could be problems with clogging due to fluff or small parts that get stuck in the pipeline.

The invention has for its object to accelerate the emptying process of the tub and to simplify it in the area of the drain path.

According to the invention this object is achieved with the features specified in claim 1. Appropriate further developments and refinements result from the following subclaims.

The advantages that can be achieved with the design according to the invention consist in the fact that the emptying process takes place rapidly due to the excess pressure that forms in the tub and a rapid spin-up can subsequently be achieved. The repeated brief spin-on, with which a water jacket or foam formation is to be prevented, is superfluous. This reduces engine wear and stress on mechanical and electrical components. Due to the absence of a drain pump or a solenoid valve in the water drain, the drain pipe can be designed to be streamlined. As a result, a high flow rate is achieved and the unimpeded conveyance of fluff and threads is possible. There can be no blockages in the drainage area. Because the compressed air is fed directly into the tub, an intermediate store with a solenoid valve in the drain path is not required.

In an advantageous embodiment, the jacket perforation of the inner drum has one compared to conventional ones Washing machines with a reduced diameter of about 2 mm. If the door sealing ring is also designed like a labyrinth, larger foreign objects can no longer get into the drainage paths. This eliminates the need for a fluff filter or a heavy trap.

An embodiment of the invention is shown purely schematically in the drawings and is explained in more detail below.

• Fig. 1: Eine schematische Darstellung der Seitenansicht des Laugenbehälters einer Waschmaschine mit einer erfindungsgemäß ausgestatteten Entleerungsvorrichtung und mit einer Ablaufleitung, deren Öffnung über der maximalen Flüssigkeitshöhe liegt;
• Fig. 2: Eine ähnliche Ausführung wie in Darstellung 1, jedoch mit einem Kugelventil;
• Fig. 3: Eine Ausschnitt des Querschnitts durch den Laugenbehälter- und Waschtrommelrand mit einer Faltenbalgdichtung.

Show it:

• Fig. 1: A schematic representation of the side view of the tub of a washing machine with an emptying device equipped according to the invention and with a drain line, the opening of which is above the maximum liquid level;
• Fig. 2: A similar design as in illustration 1, but with a ball valve;
• Fig. 3: A section of the cross section through the tub and washing drum edge with a bellows seal.

In Fig. 1 the side view of a tub (1) is shown, which is filled with wash liquor. The tub (1) receives a washing drum (2). The outer surface (3) of this washing drum has a smaller perforation of approximately 2 mm in diameter than conventional washing machines. The detergent supply line (5) opens into the upper area of the end face (4) of the tub (1). Here, water from the fresh water line (6) and detergent from the detergent dispenser (7) are introduced into the tub. A valve is located in front of the opening (8) of the detergent supply line (5) on the side of the tub (9), here in the form of a flap.

The vent line (11) opens into the upper part of the tub (10). A compressed air generator in the form of a centrifugal compressor (12) is integrated in the ventilation line (11). Another opening of the tub wall (10) is provided with a safety valve (13), which opens automatically if there is too much overpressure in the tub.

In the underside of the tub wall (10) there is the drain opening (14) to which the drain line (15) is connected. The drain line (15) is guided over the height of the maximum liquid level (16). This prevents the suds container (1) from emptying automatically and unintentionally at normal pressure. A support bearing (18) is located on the rear wall (17) of the washing machine.

2 there is a ball valve (19) in the drain line (15).

Fig. 3 shows a section of the tub rim (20) with the bellows seal (21) attached there. On its end face (4), the tub has an opening for filling laundry, which is closed by a door, not shown. A bellows seal (21) is located between the door and the tub (1). This bellows seal (21) has a lip-shaped extension (23) in the vicinity of its attachment (22) on the edge of the tub (20).

The function of the arrangement shown is as follows:
After the washing process is finished, the drain of the tub (1) starts. The centrifugal compressor (12) generates an overpressure in the tub (1). Due to the excess pressure, a valve (9) closes the opening (8) of the detergent supply line (5) and prevents pressure equalization. Due to the overpressure forming in the tub, the washing liquor is pressed out of the tub (1) steadily and quickly through the drain line (15). A safety valve (13) provides pressure relief if the excess pressure in the tub (1) exceeds a limit. Since the bellows seal (21) expands when the suds container (1) is pressurized by the excess pressure, the suds container (1) moves in the longitudinal direction. To avoid this, it must be fixed. A support bearing (18) on the rear wall of the washing machine serves this purpose. The reduction in the hole diameter of the holes in the drum jacket surface (3) and the lip-shaped extension (23) of the bellows seal (21) prevent large foreign bodies from getting into the drainage paths.

If initially only water is introduced into the tub (1) according to FIG. 2 and the detergent is only flushed in after introducing a quantity of water which fills the drain line (15), then the ball valve (19) closes the drain line (15) and prevents the washing in Detergent in the drain system. This ensures better utilization of the detergent entered.

Claims (8)

1. Drum-type washing machine, having a washing liquor container for accommodating the washing liquor, a fresh water inlet, a detergent dispenser and an intake pipe leading to the washing liquor container, an air venting means for removing air from the washing liquor container and a means for preventing the discharge of washing liquor during the washing process, a means for producing compressed air being disposed in the washing machine, characterised in that the washing liquor container (1) is emptied by the introduction of the compressed air produced by said compressed air producing means.
2. Drum-type washing machine according to claim 1, characterised in that the compressed air is conducted into the washing liquor container via an intake pipe, and in that all of the apertures in the washing liquor container above the maximum level of liquid, which are not used for the introduction of compressed air, are closable by means which prevent the compressed air from escaping from the washing liquor container.
3. Drum-type washing machine according to one of claims 1 or 2, characterised in that the compressed air is introduced into the washing liquor container (1) via the air vent pipe (11).
4. Drum-type washing machine according to one of claims 1 to 3, characterised in that the washing liquor is prevented from being discharged during the washing process by a drain pipe (15), which extends above the maximum level of liquid (16) in the washing liquor container (1).
5. Drum-type washing machine according to one of claims 1 to 3, characterised in that an automatically closing non-return valve in the outlet of the washing liquor container or a ball valve (19) in the drain pipe (15) closes the outlet aperture (14) during the washing process.
6. Drum-type washing machine according to one of claims 1 to 5, characterised in that the surface of the drum has holes having a diameter of about 2 millimetres.
7. Drum-type washing machine according to one of claims 1 to 6, characterised in that a bellows seal (21) is disposed between the door for closing the opening in the end face of the washing liquor container and the edge (20) of the washing liquor container, and in that the bellows seal (21) has a lip-shaped extension (23), which is orientated towards the washing drum (2).
8. Drum-type washing machine according to one of claims 1 to 7, characterised by a support bearing (18) on the rear wall (17) of the washing machine housing.

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