Water softener abstract
A method is provided for regenerating a mass of active resin contained
in a water softening device connected in the water filling circuit
of a washing machine. The water softener device has an internal
volume which is equal to the sum of the volume of the mass of resin
plus a free volume, and is selectively supplied with both fresh
water and brine through respective valves controlled by a program
control device. The water softening device is supplied with a volume
of brine during a first period of time, and is subsequently supplied
with a complementary volume of water during a second period of time.
The sum of the volume of brine, which is selected according to the
hardness of the supply water, and the complementary volume of water
is equal to the free volume of the water softening device.
Water softener claims
What is claimed is:
1. In a washing machine having a water softening device containing
water softener in the form of a mass of active resin, and which
device has a volume equal to the volume of the mass of active resin
contained therein plus a free volume, a method for regenerating
the water softener comprising the steps of:
supplying brine to the water softening device during a first predetermined
period of time, thereby metering the amount of brine supplied to
the water softener contained therein;
subsequently supplying fresh water to the water softening device
during a second period of time, thereby metering the amount of fresh
water supplied; and
regulating the durations of said first and second periods of time
such that the sum of the metered volume of brine and the metered
volume of fresh water is substantially equal to said free volume
of the water softening device.
2. The method of regenerating water softener in a washing machine
as claimed in claim 1 wherein the duration of the first period
of time is regulated such that the amount of brine supplied to said
water softening device is proportional to the degree of hardness
of water supplied to the washing machine from main water lines.
3. The method of regenerating water softener in a washing machine
as claimed in claim 1 wherein said first and said second periods
of time are regulated such that said sum of the metered volume of
brine and the metered volume of fresh water is less than or equal
to said free volume.
Water softener description
BACKGROUND OF THE INVENTION
The present invention relates to an improved method for regenerating
water softener in a washing machine, particularly in an automatic
As is common knowledge, the water supply circuit of machines such
as automatic dishwashing machines is usually provided with a water
softening device containing active resins that are regenerated periodically
by the addition of metered quantities of brine. This brine is formed
by passing water through a salt reservoir. In order that the extent
of the regeneration of the water softener corresponds to the actual
degree of hardness of the supply water, the quantity of brine to
be metered into the water softening device is appropriately adjusted.
In an alternative method, the water softener is regenerated through
the addition of a constant quantity of brine thereto, the salt concentration
of which is varied accordingly in this case. Such a method is disclosed,
for instance, in EP-B-0 219 704 in which mechanical means are provided
to vary the salt concentration by changing the length of the average
flow path of a predetermined volume of regeneration water passing
through a mass of salt situated inside a specially provided reservoir.
In this way, in the case of a very high degree of hardness of the
supply water, it is practically possible to do away with the need
of using considerable volumes of brine which might otherwise overflow
into the wash tank of the machine and give rise to corrosion problems.
On the other hand, the means for adjusting the salt concentration,
which are housed within the salt reservoir, may turn out to be quite
difficult to reach and their adjustment may turn out to be undesirably
SUMMARY OF THE INVENTION
It is the main object of the present invention to provide a method
for regenerating water softener in a washing machine, which will
enable the extent of the regeneration of the water softener to be
easily, conveniently and accurately adjusted according to the degree
of hardness of the supply water, and which will not create any corrosion
problem in the washing tank of the machine.
It is a further object of the present invention to provide a water
softener regeneration method which can be implemented in a washing
machine provided with a water supply circuit that is substantially
simple and reliable in its design.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features and advantages of the invention will become apparent
in the following description, by way of non-limiting example, with
reference to the accompanying FIGURE, which is a schematic view
of a preferred embodiment of the water supply circuit of a washing
machine which is capable of performing the method according to the
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the FIGURE, numeral 10 designates the wash tank
(shown only partially) of an automatic washing machine, such as
a domestic dishwashing machine. The wash tank 10 is adapted to be
supplied with fresh water by means of a water supply pipe 4 in which
a controlled inlet valve 1 an air space 3 and a water softening
device 16 are provided in series. In a per se known way, the water
softening device 16 houses a granular mass 17 of ion-exchange resin,
or similar active resins, which are capable of reducing the hardness
of the fresh water and which requires periodical regeneration. The
granular mass 17 only partially fills the water softening device
16 the overall internal volume of which therefore also includes
a free volume which is not occupied by granular mass 17 and to
which reference will be made hereinafter.
In a similarly per se known way, water leaking into the air space
3 is collected in an underlying tray 6 the bottom of which is connected
with the wash tank 10. The water supply pipe 4 is preferably provided
upstream of the air space 3 with a bifurcation 12 having a calibrated
cross section and adapted to deliver water to a storage reservoir
2 communicating with the collection reservoir 6 and therefore with
the outside environment, through an overflow partition wall 13.
Tubing 5 connects the bottom portion of the storage reservoir 2
with the inlet of an underlying salt reservoir 7. In a preferred
way, such an inlet comprises a perforated diffuser 15 located on
the bottom of the reservoir 7. The latter is further provided with
an outlet which preferably comprises a hollow outlet body 11 extending
upwards within the salt reservoir 7. The hollow outlet body 11 is
provided with at least an upper opening 9 and its bottom portion
is connected with the water supply pipe 4 upstream of the water
softening device 16 through a controlled valve 14.
The valves 1 and 14 are controlled by the program control device
of the machine, which is schematically shown and designated by numeral
8 in the FIGURE. The program control device 8 is of a per se known
type, such as for instance of an electromechanical type. In a preferred
way, however, the program control device is of an electric type,
including for instance, a Motorola 6804 or 6805 microprocessor.
In any case, the program control device 8 is programmed to control
one or more operational cycles of the machine, as may be selected
by the user, whereby the phases of these cycles are automatically
performed in sequence. In a substantially conventional way, the
operational cycles may include a series of phases such as a water
fill phase, different washing and rinsing phases, a water discharge
phase, a water softener regeneration phase, etc. Preferably, but
not exclusively, each of the water softener regeneration phases
is carried out at the end of a corresponding water fill phase.
As should be clearly apparent to anyone skilled in the art, the
program control device 8 and in particular the microprocessor associated
therewith, is able to establish the operational cycle to be carried
out by the machine in a per se known manner by setting various process
parameters (such as for instance the moments at which the various
functional parts of the machine are to be actuated or energized,
the duration of actuation or energization thereof, etc.) determining
the timing of the phases making up the various selectable operational
cycles of the machine.
For instance, in order to perform a water fill phase, the program
control device 8 causes the valve 1 which is of the same normally
closed type as the valve 14 to open for a pre-set period of time.
A corresponding quantity of water from the mains is then let into
the wash tank 10 through the water supply pipe 4 after having been
appropriately softened by the granular mass 17 of resins in the
water softening device 16. During this phase, the storage reservoir
2 is filled with water from the bifurcation 12 of the water supply
The various washing, rinsing and similar phases are substantially
of a traditional type. As such, they do not form any particular
part of the invention and will therefore not be described any further
for the sake of simplicity.
However, according to a main feature of the invention, each regeneration
phase is carried out in at least two distinct, sequential periods
of time. In a first time period, the program control device 8 causes
the valve 14 to open, while the other valve 1 remains in its closed
condition. Consequently, a corresponding volume of water stored
in the reservoir 2 flows by gravity through the tubing 5 passes
through the mass of salt housed in the reservoir 7 and enters the
water softening device 16 through the valve 14.
Inside the salt reservoir 7 in particular, the water flows from
the diffuser 15 towards the opening 9 of the hollow outlet body
11 and, in doing this, it follows a predetermined average path which
is schematically designated by numeral 18 in the FIGURE. The water
converts therefore into brine having a predetermined salt concentration,
preferably close to saturation.
The program control device 8 can control the valve 14 to allow
any volume of brine, between minimum and maximum volumes, to flow
into the water softening device 16. Therefore, by programming the
program control device 8 for instance when installing the machine,
the duration of the afore-described first period in which the valve
14 is opened can be set so that the volume of the brine flowing
into the water softening device 16 will correspond to the degree
of hardness of the supply water.
In accordance with a further aspect of the invention, the above-mentioned
maximum volume is smaller than the aforementioned free volume of
the water softening device 16 while the minimum volume can be decided
upon and set by the manufacturer according to actual needs.
After this first period of the regeneration phase, the program
control device 8 then causes the valve 1 to open for a second period
of time during which the valve 14 is returned to its closed condition.
This brings about the inflow of a complementary volume of water
from the mains through the water softening device 16 which is instrumental
in displacing the volume of brine previously let into the water
softening device 16 and bringing it into contact with the entire
granular mass 17 of resin.
During the regeneration phase, the granular mass 17 is stirred
and mixed up by the water and brine mixture, so that a regeneration
process is brought about and completed in a thorough and effective
Quite obviously, during the second period of the regeneration phase,
the brine let into the water softening device 16 during the first
period is diluted by the complementary volume of water from the
mains. Therefore, appropriate consideration of this dilution should
be taken in establishing the duration of the first and second periods
to effectively deal with the degree of hardness of the fresh water
from the mains. This, however, is a mere problem of general dimensioning
of the machine, which is therefore within the ability of one skilled
in the art, and which can be easily and accurately solved particularly
when a program control device 8 of an electronic type is employed.
According to a further aspect of the invention, the program control
device 8 can set the duration of the second period of the regeneration
phase such that the complementary volume of water let into the water
softening device 16 from the mains is substantially equal to and
in any case not greater than the difference between the aforementioned
free volume of the water softening device 16 and the volume of brine
let into the water softening device 16 during the first period of
the regeneration phase.
Such a setting of the program control device 8 which can for instance
be carried out when the machine is being installed, enables the
entire granular mass 17 of resin to be regenerated, while at the
same time preventing the brine from flowing over into the wash tank
10 where it might give rise to the aforementioned corrosion problems.
It should be noted that the term "free volume of the water
softening device 16" is to be understood as not referring solely
to the volume of the water softening device 16 which is not actually
occupied by the granular mass 17 of resin, but also includes the
volume of that portion of the water supply pipe 4 situated downstream
of the water softening device 16.
From the above description and considerations, it is apparent that
the method according to the invention can be implemented practically,
easily and accurately in a washing machine of a substantially per
se known type, without the need for special adjustment means.
It will also be appreciated that the above-described method may
be modified in various ways without departing from the scope of
the invention. For instance, the periods during which both of the
valves 1 and 14 are open during each regeneration phase, and therefore
also the volumes of brine and water that are let into the water
softening device 16 can vary depending upon the general dimensions
of the machine.
Furthermore, the method according to the invention can similarly
be implemented in a washing machine equipped with a water supply
circuit different from that described above. For instance, the tubing
5 can connect the salt reservoir 7 with the water supply mains,
rather than with the storage reservoir 2 preferably through the
valve 1. In such a case, of course, the valve 1 will be opened even
during the second period of the regeneration phase. In an alternative
approach, the controlled valve 1 may be a two-way valve controlled
by the program control device 8 in such a way as to selectively
place the water supply mains in communication with the tubing 5
and the pipe 4 during the first and second periods, respectively,
of the regeneration phase.