[0001] The invention relates to a method of regenerating a water-softening installation
for an automatic washing machine or dishwasher, which has a wash or rinse container
connected to a water container which is filled with active resin and into which fresh
water can be led for softening in intake phases via a software-driven intake valve,
a storage container and a water supply pipe and into which saline solution for regenerating
the resin can be led from a saline solution container by means of a software-driven
regeneration valve, a non-return valve being connected after the regeneration valve
between the storage container and the saline solution container, said regeneration
valve being permeable only in the direction towards the water softener and connected
on the outlet side with the entrance of the water softener and of a water supply pipe
connected electrically to it and taken from the storage container, the outlet of the
storage container being arranged above the saline solution container and the water
softener in such a way that, when the intake valve is open, fresh water can only be
led into the water softener via the water supply pipe when the storage container is
full.
[0002] An automatic washing machine with a regeneration phase of this kind is known from
EP 0 496 957 B1. In the first part of the regeneration phase (intake valve closed,
regeneration valve open) when fresh water stored in the storage container is applied,
a pre-measured amount of saline solution is led from the saline solution container
into the water softener. In the second part of the regeneration phase (intake valve
open, regeneration valve closed) an additional amount of fresh water is led into the
water softener. The water softener has a total inner area that is as big as the volume
of the resin poured into it, plus some free space. The sum of the measured saline
solution and of the above-mentioned additional amount of fresh water must be substantially
as big as the total free space in the water softener, so that in the water softener
the process of regeneration is improved by a kind of stirring or mixing effect. In
this connection it should be noted that in regeneration consideration should be given
to the variable degree of hardness of the fresh water used. It is not easy to optimize
regeneration in this way.
[0003] The washing machine according to DE 37 10 511 A1 has a water-softening installation
of a similar structure. However, in this, too, the stirring and mixing effect during
the regeneration phase is not optimal.
[0004] The object of the invention is to design a method of the kind mentioned initially
in such a way that the regeneration process is optimized during the regeneration phase
in a simple fashion.
[0005] This object is achieved according to the invention in that the regeneration valve
is opened in the regeneration phase and thus a common water level is set in the storage
container, in the saline solution container, in the connecting pipe and the water
softener up to the wash or rinse container, which level lies above the upper water
level of the saline solution container and the water softener, and in that a through
pulse is created in the water supply pipe by opening the intake valve for a short
time in the regeneration phase.
[0006] In the first part of the regeneration phase the saline solution is led from its container
into the water softener and the fresh water stored in the storage container can be
pre-measured and adapted optimally to the degree of hardness of the fresh water used.
In the second part of the regeneration phase an air-pressure pulse is created in the
water supply pipe and this pulse can extend through the water softener up to the wash
or rinse container. By means of the air-pressure pulse, a stirring and eddy effect
is created so that the saline solution led in reaches the reaction zone of the resin
more effectively. The portion of the saline solution standing in the lower region
of the water softener is forced upwards by the air-pressure pulse, so that a kind
of exchange of the saline solution takes place and said saline solution participates
more effectively in regeneration without changing, through the addition of extra fresh
water, the concentration of the saline solution which is, of course, adjusted to the
degree of hardness of the fresh water used.
[0007] Regeneration can easily be further improved by creating, in the regeneration phase,
after the regeneration valve has been closed, a plurality of air-pressure pulses in
the water-supply pipe by repeatedly opening the intake valve briefly. The air-pressure
pulses each time force the portion of the saline solution in the water softener upwards
and cause repeated exchange.
[0008] The fresh water source can be decoupled quite simply from the water-softening installation
by the storage container being connected with the exit of the intake valve via a free
air gap and by the in-flow into the storage container being arranged above the outgoing
water supply pipe in the upper region of the storage container.
[0009] The invention is explained in more detail with the aid of an embodiment, given by
way of example and shown in the drawings. These show:
- Fig. 1 -
- the water-softening installation for an automatic washing machine showing its state
after the first part of a regeneration phase and
- Fig. 2 -
- the water-softening installation in the second part of the regeneration phase.
[0010] First of all, the structure of the water-softening installation of an automatic washing
machine according to the invention is to be explained in more detail with the aid
of Fig. 1. The intake of fresh water into the water-softening installation is released
and stopped via an intake valve 1, controlled by a program control unit 8. For decoupling,
i.e. to prevent the flow of water back into the fresh water source, e.g. the water
mains, the intake valve 1 is connected, via a free air gap 3, with the storage container
2, which has a capacity e.g. of 300 cm
3 and is connected with the entrance of the water softener 16 via the water supply
pipe 4 arranged in the upper region. In the water softener 16 a quantity of active
resin 17 is accommodated between a lower membrane 21 and an upper membrane 22. The
water supply pipe 4 leads from the water softener 16 on to the wash container 10.
[0011] The outlet arranged in the lower region of the storage container 2 leads via a connecting
pipe 5 and a regeneration valve 14, controlled by a program control unit 8, to the
entrance of a saline solution container 7, which is filled with salt. The exit of
the saline solution container 7 leads via a non-return valve 20 to the entrance of
the water softener 16, to which the water supply pipe 4 is also joined. The non-return
valve 20 is only permeable in the direction from the saline solution container 7 to
the water softener 16.
[0012] Before the programme starts, the intake valve 1 and the regeneration valve 14 are
closed. The storage container 2 is partly filled. If the intake valve 1 is then opened,
the storage container 2 is then filled with the regeneration volume of fresh water,
i.e. with approximately 300 cm
3. Once this has happened, the fresh water flows via the water supply pipe 4 into the
water softener 16 and is softened in it, because the resin binds the hardness components
of the fresh water. The soft water then flows from the water softener 16 into the
wash container 10, where it is used for rinsing and/or washing processes.
[0013] Shortly before the end of the programme, i.e. before the regeneration phase begins,
the intake valve 1 and the regeneration valve 14 are closed. The storage container
2 is filled and there is also saline solution in the saline solution container 7.
In the water softener 16 the resin has bound the hardness components. In this situation
the regeneration valve 14 is opened. From the storage container 2 the pre-measured
regeneration volume of fresh water flows into the saline solution container 7 (pressure
from geodetic level). The non-return valve 20 opens and saline solution flows into
the water softener 16.
[0014] The general water level 6 is thereby set, extending uniformly through the connecting
pipe 5 between the storage container 2 and the saline solution container 7, through
the saline solution container 7, the water supply pipe 4, the water softener 16 and
the lower region of the wash container 10. The hardness components are released by
the saline solution and the resin 17 is regenerated. The volume 23 of saline solution
standing in the water supply pipe 4 does not come into contact with the resin and
remains unused. After the first part of the regeneration phase, the regeneration valve
14 is closed and the intake valve 1 is opened briefly. Thus, as shown in Fig. 2, fresh
water is discharged briefly into the storage container 2. The volume of water discharged
is, however, smaller than the capacity of the storage container 2, so water cannot
reach the water softener 16. However, an air-pressure pulse is created, which is transmitted
via the air gap 3 and the water supply pipe 4 as far as the wash container 10, as
shown by the arrows marked Δρ. Due to this air-pressure pulse the water level 6 is
altered briefly. The saline solution in the water softener 16 is pressed upwards by
the resin in the water softener 16, which also leads to turbulent mixing of the resin.
This mixing can be repeated many times, the intake valve 1 being opened briefly each
time. In this process the volume of the fresh water led in should not exceed the volume
of the storage container 2.
[0015] The regeneration process is supported and optimized by these air-pressure pulses
created in the second part of the regeneration phase, without diluting the concentration
of the saline solution.
1. Method of regenerating a water-softening installation for an automatic washing machine
or dishwasher, which has a wash or rinse container connected to a water container
which is filled with active resin and into which fresh water can be led for softening
in intake phases via a software-driven intake valve, a storage container and a water
supply pipe and into which saline solution for regenerating the resin can be led from
a saline solution container by means of a software-driven regeneration valve, a non-return
valve being connected after the regeneration valve between the storage container and
the saline solution container, said regeneration valve being permeable only in the
direction towards the water softener and connected on the exit side with the entrance
of the water softener and of a water supply pipe connected electrically to it and
taken from the storage container, the outlet of the storage container being arranged
above the saline solution container and the water softener in such a way that, when
the intake valve is open, fresh water can only be led into the water softener via
the water supply pipe when the storage container is full,
characterised in that
in the regeneration phase, the regeneration valve (14) is opened and thus a common
water level (6) is set in the storage container (2), in the saline solution container
(7), in the connection pipe (5) and the water softener (16) up to the wash or rinse
container (10), said level lying above the level of the saline solution container
(7) and of the water softener (16), and in that an air-pressure pulse is created in
the water supply pipe (4) by opening the intake valve (1) briefly in the regeneration
phase.
2. Method according to claim 1,
characterised in that,
in the regeneration phase, after the regeneration valve (14) has been closed, a plurality
of air-pressure pulses is created in the water supply pipe (4) by repeatedly opening
the intake valve (2) for brief periods.