U.S. patent application number 13/981039 was filed with the patent office on 2014-03-20 for home appliance.
This patent application is currently assigned to ELECTROLUX HOME PRODUCTS CORPORATION N.V.. The applicant listed for this patent is Mario Filippetti, Andrea Zattin. Invention is credited to Mario Filippetti, Andrea Zattin.
Application Number | 20140075682 13/981039 |
Document ID | / |
Family ID | 44148447 |
Filed Date | 2014-03-20 |
United States Patent
Application |
20140075682 |
Kind Code |
A1 |
Filippetti; Mario ; et
al. |
March 20, 2014 |
Home Appliance
Abstract
A home appliance (2), in particular dishwasher or laundry
treatment apparatus, further in particular a laundry treatment
apparatus capable of washing and/or drying, includes a liquid
supply channel (24) and/or a liquid reservoir (22) and a droplet
spraying device (26). The droplet spraying device includes a
membrane (36) arranged in fluid connection with the liquid supply
channel (24) and/or the liquid reservoir (22). The membrane (36)
has a plurality of openings (38), and at least one actuator (40) is
provided for actuating the membrane (36).
Inventors: |
Filippetti; Mario;
(Campoformido (UD), IT) ; Zattin; Andrea;
(Solesino (PD), IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Filippetti; Mario
Zattin; Andrea |
Campoformido (UD)
Solesino (PD) |
|
IT
IT |
|
|
Assignee: |
ELECTROLUX HOME PRODUCTS
CORPORATION N.V.
Brussels
BE
|
Family ID: |
44148447 |
Appl. No.: |
13/981039 |
Filed: |
January 19, 2012 |
PCT Filed: |
January 19, 2012 |
PCT NO: |
PCT/EP12/50760 |
371 Date: |
December 2, 2013 |
Current U.S.
Class: |
8/137 ; 134/105;
134/153; 134/174; 134/175; 134/184; 134/25.2; 68/13R; 68/207 |
Current CPC
Class: |
A47L 15/4291 20130101;
D06F 58/24 20130101; A47L 15/16 20130101; D06F 39/088 20130101;
D06F 58/203 20130101; D06F 39/008 20130101; A47L 15/4217
20130101 |
Class at
Publication: |
8/137 ; 134/184;
68/207; 68/13.R; 134/105; 134/174; 134/175; 134/153; 134/25.2 |
International
Class: |
A47L 15/42 20060101
A47L015/42; D06F 39/08 20060101 D06F039/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 24, 2011 |
EP |
11151831.2 |
Claims
1. A home appliance capable of treating articles, comprising a
liquid supply channel and/or a liquid reservoir and a droplet
spraying device, the droplet spraying device comprising: a membrane
arranged in fluid connection with the liquid supply channel and/or
the liquid reservoir, wherein the membrane has a plurality of
openings, and at least one actuator for actuating the membrane to
transmit liquid therethrough.
2. A home appliance according to claim 1, wherein the home
appliance comprises a heat exchanging device, and wherein the
droplet spraying device is configured to spray liquid supplied to
the membrane by the liquid supply channel and/or the liquid
reservoir onto one or more surfaces of the heat exchanging
device.
3. A home appliance according to claim 2, wherein the droplet
spraying device is arranged above the heat exchanging device and/or
in or close to an air supply channel for flowing air to the heat
exchanging device.
4. A home appliance according to claim 1, wherein the home
appliance comprises a compartment for articles to be treated, and
wherein the droplet spraying device is configured to spray droplets
into the compartment.
5. A home appliance according to claim 4, wherein the droplet
spraying device is arranged at a wall section forming part of the
enclosure of the compartment.
6. A home appliance according to claim 4, wherein the droplet
spraying device is arranged within the compartment, at a movable or
stationary element thereof.
7. A home appliance according to claim 6, wherein the droplet
spraying device is arranged at a loading door for closing a loading
opening and/or is arranged at a gasket arranged between a loading
opening and the compartment.
8. A home appliance according to claim 4, wherein the home
appliance comprises a rotatable drum forming at least part of the
compartment and the droplet spraying device is configured to spray
droplets into the drum.
9. A home appliance according to claim 1, wherein the home
appliance comprises a compartment for articles to be treated, in
particular a laundry storage compartment or a dishes storing
compartment, and wherein the droplet spraying device is arranged in
an air flowing channel upstream of the compartment, the air flowing
channel forming part of a process air channel and/or part of an air
circulation channel.
10. A home appliance according to claim 1, wherein the membrane is
supported by the actuator, and wherein the actuator (40) comprises
one or more electrostriction, magnetostriction or piezoelectric
elements adapted to deflect when electrically and/or magnetically
excited.
11. A home appliance according to claim 1, wherein the membrane
forms at least part of the at least one actuator.
12. A home appliance according to claim 1, wherein in a first
operation mode of the droplet spraying device a vibration frequency
and/or speed and/or amplitude of the membrane actuation is higher
than in a second mode of operation.
13. A home appliance according to claim 2, wherein in the first
operation mode of the droplet spraying device the liquid is
completely, substantially or at least partially sprayed by the
membrane, and in the second operation mode of the droplet spraying
device the liquid is completely, substantially or at least
partially flown through an outlet of the liquid supply channel or
the liquid reservoir.
14. A method of operating a home appliance according to claim 1,
wherein in a first step liquid supplied to the membrane is sprayed
by the droplet spraying device, and in a succeeding step the liquid
reservoir and/or the liquid supply channel is washed by a liquid
flow.
15. A home appliance according to claim 2, wherein the droplet
spraying device is configured to spray liquid onto the heat
exchanging surfaces of the heat exchanging device.
16. A home appliance according to claim 3, wherein the droplet
spraying device is arranged in or close to said air supply channel,
and wherein the air supply channel is part of a processing air
channel.
17. A home appliance according to claim 4, wherein said compartment
comprises a laundry storage compartment or a dishes storing
compartment.
18. A home appliance according claim 8, wherein the droplet
spraying device is arranged at a front and/or rear closure element,
the front or rear closure element covering or closing a front or
rear opening of the drum, respectively.
Description
[0001] The invention relates to an improved home appliance,
preferably to a laundry treatment apparatus or a dishwasher and
further in particular to a laundry treatment apparatus capable of
washing and/or drying. The invention set forth below is in
particular suitable for washing machines and dryers, especially
tumble dryers, encompassing condensation dryers, heat pump dryers,
exhaust or circulation ventilation dryers or washing machines with
drying function.
[0002] In the art home appliances are known, which allow for the
dispensing of a fluid for the purpose of cleaning components of
such home appliances, e.g. for cleaning a component of a heat
exchange system of the home appliance like a condenser surface.
Such necessity for cleaning arises for example with dryers,
especially condensate dryers or heat pump dryers, where one of the
problems of efficiency over time is related to the soiling of the
evaporator. The fluff removed by the laundry during the drying
process is carried into the cooling system by the processing air.
Part of the fluff is retained by the lint filter but small
particles may overcome this barrier. This effects a reduction of
the thermal exchange power of the surfaces and in worst case the
clogging of the air path. WO 2009/050004A1 discloses a method and a
device for cleaning a component arranged in a process air circuit
of a dryer by a sudden gush of water, especially by a gush of
condensed water stored in a storage chamber. Further cleaning
devices of the above kind are known from DE 37 38 031 C2 and DE 43
33 901 C2. Herein fluff is removed by a flushing device which
comprises jets provided with condensate water pressurized by a
pump.
[0003] Devices of the above kind need a complex construction
including powerful pumps for effectively cleaning the desired
component by dispensing of pressurized fluid and/or a large amount
of cleaning fluid for flushing.
[0004] In view of the above it is an object of the present
invention to provide a home appliance and a method having or using
a droplet spraying device allowing for a simple arrangement for
providing droplets.
[0005] The invention is defined in claims 1 and 15, respectively.
Particular embodiments are set out in the dependent claims.
[0006] A home appliance according to the present invention is in
particular a laundry treatment apparatus or a dishwasher. Such
laundry treatment apparatuses encompass washing machines, dryers,
especially tumble dryers like condensate or heat pump dryers and
washing machines with drying function. Generally a home appliance
of the inventive kind can be any home appliance, wherein the
dispensing of a liquid fluid, in particular the spray dispensing of
a fluid, is provided. Fluids to be dispensed can be water, for
example condensate water, cleansing agents, additives for fabric
finishing or alike liquids.
[0007] A home appliance according to the present invention
comprises a liquid supply channel and/or a liquid reservoir as well
as a droplet spraying device. Both the liquid supply channel and
the liquid reservoir serve the purpose of feeding or supplying the
droplet spraying device with the liquid, wherein also the liquid
supply channel can serve as a liquid reservoir. The liquid
reservoir and/or the liquid supply channel are meant to be arranged
in fluid communication with the droplet spraying device, i.e. such,
that liquid from the liquid supply channel and/or the liquid
reservoir can be fed to the droplet spraying device in an
appropriate manner. In a preferred embodiment, the droplet spraying
device is arranged at a section of the liquid supply channel,
preferably at an end region thereof.
[0008] Generally the liquid supply channel and/or the liquid
reservoir has an inlet for supplying liquid thereto. In an
embodiment the liquid supply channel and/or the liquid reservoir
may have an outlet for draining liquid therefrom. The liquid supply
channel may be connected to a liquid source, for example to a fresh
water tap or to (another) liquid reservoir. The liquid supply
channel may be a flow-through channel adapted to flow the liquid
through the channel, in particular adapted to flow the liquid to
the droplet spraying device, further in particular through its
inlet. In an embodiment controllable valve can be connected between
the droplet spraying device and the liquid reservoir or liquid
source, or the valve is provided between the liquid reservoir and
the another liquid reservoir
[0009] It is to be noted that in this document and in the
claims--unless otherwise indicated--the element "a droplet spraying
device" is a single, discrete droplet spraying device or is a
plurality of droplet spraying devices or is a multiple droplet
spraying device. The multiple droplet spraying device is preferably
an arrangement of a plurality (e.g. 2, 3, 4, . . . ) of discrete or
coupled-together droplet spraying devices. For example one surface
area of the liquid supply channel and/or the liquid reservoir
comprises a distributed (e.g. linear or matrix-like) arrangement of
adjacent droplet spraying devices.
[0010] One or more individual droplet spraying devices of a
multiple droplet spraying device can each be supplied by a discrete
supply channels and/or be fed by a discrete liquid reservoirs. A
multiple droplet spraying device also may be fed from common liquid
supply channel and/or a common liquid reservoir. Hereby
combinations of discrete supply of one or more droplet spraying
devices and common supply of further droplet spraying devices by
one or more liquid supply channels and/or one or more liquid
reservoirs may be provided. For example, multiple droplet spraying
devices for bringing out fabric finishing additives each are
supplied by a discrete liquid supply channel, for example in fluid
connection to a common liquid reservoir, or each to another liquid
reservoir. Preferably the multiple droplet spraying device for
bringing out water or condensate water when cleaning an evaporator
is supplied directly by a common liquid reservoir. In an embodiment
also liquid can be supplied to one or more liquid supply channels
and/or liquid reservoirs from different or same fluid
sources/reservoirs.
[0011] The droplet spraying device according to the present
invention, which is based on membrane vibration, comprises a
membrane arranged in fluid connection with the liquid supply
channel and/or the liquid reservoir. A fluid connection may be
established such that liquid from the liquid supply channel and/or
the liquid reservoir is brought into direct contact with the
membrane. Liquid may be fed to the membrane by a liquid supply
channel or a liquid reservoir apt for a capillary feed of the
membrane or liquid may be deposited directly onto the membrane by
the liquid supply channel and/or the liquid reservoir. Liquid may
be supplied directly to a surface of the membrane, especially to a
back surface thereof, alternatively for example to a front
surface.
[0012] The membrane of the droplet spraying device is meant to
generate droplets by being actuated by at least one actuator of the
droplet spraying device, the droplets especially providing a fine
aerosol spray or mist. The membrane has a plurality of openings. By
providing openings, liquid can comfortably be fed to a backside of
the membrane, whereas droplets emerge at a front side during
operation. Such a perforate membrane can produce a powerful mist
when vibrated by the actuator and allow for the convenient
separation of a treatment region facing the front side of the
membrane and a liquid supply next to the back side.
[0013] The openings of the membrane can have an average diameter
such as to exert a capillary force onto the liquid and preventing
escape of the liquid through the opening when the actuator is not
operated (or when the actuator is operated such that the capillary
or surface force can not be overcome). Operation of the actuator
preferably is effected at a vibrational resonance frequency of the
droplet spraying device, allowing for low driving energy.
[0014] Generally the membrane may be formed from a sheet material,
for example from an electro-formed sheet wherein the sheet material
may be a metallic material, a metal compound, plastic material, or
ceramic. Such membranes including openings can for example be
produced by a photo-lithographic process in combination with an
electroforming process. The membrane may be formed as circular
disc, for example also comprising a circular layer of polymer.
[0015] The membrane can comprise a sheet with openings defined in
an array. The openings can be tapered holes, i.e. holes of a
cross-sectional area which is reduced in a direction from the back
to the front side of the membrane. Such tapered holes may enhance
the dispensing of droplets and are apt to reduce the necessary
amplitude of a vibration of the membrane for generating droplets of
a desired size. Such tapered conical perforations can for example
be formed in a polymer layer of the membrane.
[0016] An actuator can be a piezoelectric and/or an
electrostrictive actuator, for example also a piezomagnetic or a
magnetostrictive actuator which comprises one or more of
electrostrictive, magnetostrictive or piezoelectric elements
adapted to deflect. Advantageously the actuator comprises an
element enabled to deflect according to an external excitation, for
example by applying an AC voltage. Upon bending or deflecting the
membrane operatively connected to the actuator is vibrated
(actuated). Such bending can be caused by an applied field, e.g. an
electric or magnetic field. It should be noted that fields for
actuating the membrane via deflecting of an excitable element or
the actuator, respectively, are in particular alternating fields.
Such alternating fields in particular allow for vibration of the
membrane for the generation of droplets.
[0017] An actuator can be formed integrally with the membrane, e.g.
such, that the membrane is part of the actuator or the actuators or
wherein the membrane itself is the actuator. The membrane may also
be supported on the actuator. Alternative examples for suitable
actuators may include a coil arrangement which supports the
membrane, the coil arrangement comparable to that of a speaker,
e.g. a dome tweeter or cone speaker.
[0018] The membrane may comprise one or more electrodes and one or
more backing electrodes arranged at a distance or with a gap from
the membrane, wherein in particular the one or more backing
electrodes are arranged facing a front side and/or backside of the
membrane. Such an actuator structure resembles an electret
structure as used for example in an electret microphone or speaker.
The one or more backing electrodes may be formed on or arranged at
a body of the droplet spraying device or at or in the liquid supply
channel and/or liquid reservoir.
[0019] Preferably the droplet spraying device is supplied with
liquid without the requirement of a pump (e.g. only a liquid supply
in fluid connection with the membrane is provided). Because of its
possible small and slim but simple and rigid layout the droplet
spraying device offers the chance to place the droplet spraying
device in positions, where common nozzles can not be applied.
Additionally the dimension of the droplets, the amount of mist and
the direction of the mist flow or the droplets respectively can be
managed by the device characteristic and/or by an electronic board
connected therewith. Such a driving board can be a low-cost low
voltage electronic board, the energy consumption of which is
negligible. The droplet spraying device is highly adaptable to flat
surfaces, applicable for a wide range of liquids and not sensible
to clogging. Moreover there is no dead time in the build-up of
droplets.
[0020] In an embodiment the home appliance has one or more such
droplet spraying devices, each in fluid connection with a liquid
channel and/or a liquid reservoir. A plurality of droplet spraying
devices can be arranged adjacent to each other or spatially
distributed. For example, one or more droplet spraying devices can
be arranged at or in one component of the home appliance and one or
more droplet spray devices can be arranged at another component. A
droplet spraying device may be installed neighboring or in a
compartment of the home appliance, for example neighboring a
laundry storing compartment, especially such that spraying droplets
into the compartment is possible, whereas another droplet spraying
device is for example arranged next to a heat exchanging device of
said appliance, in particular for cleaning the same. A heat
exchanging device of the (a) home appliance can be a condenser,
evaporator or radiator for dissipating heat.
[0021] As already mentioned, the invention can be carried out
advantageously in connection with a home appliance comprising a
heat exchanging device. Such home appliances are in particular
dryers, e.g. condensation and heat pump dryers or washing machines
with drying function. In such home appliances the droplet spraying
device can be configured to spray liquid supplied to the membrane
by the liquid supply channel and/or the liquid reservoir onto one
or more surfaces of the heat exchanging device, in particular to
spray liquid onto the heat exchanging surfaces of the heat
exchanging device. Convenient surfaces for being sprayed are
especially evaporator surfaces of a heat pump dryer which need
cleaning or washing as fluff is otherwise expected to soil or clog
those. Advantageously the droplet spraying device based on the
actuator-operated membrane is able to work with a liquid in form of
condensed water normally present in such a home appliance and to
give a powerful and directed mist to remove fluff stuck on the
evaporator surfaces.
[0022] In an embodiment the droplet spraying device can be arranged
above the heat exchanging device or the component to be cleaned by
sprayed droplets and/or in or close to an air supply channel for
flowing air to the heat exchanging device, wherein in particular
the air supply channel is part of a processing air channel.
Advantageously the droplet spraying device thereby can be arranged
to spray droplets into the air supply channel at a region upstream
the heat exchanging device, in particular be arranged next to or in
the air supply channel upstream the heat exchanging device. In both
cases the droplets may advantageously experience an accelerating
force, i.e. by gravity or the process air flow within the air
supply channel in a direction which supports the droplet spray
effect exerted by the droplet spraying device and in the
consequence the removal of residue.
[0023] Preferably the home appliance includes a compartment for
articles to be treated. Such a compartment may be a laundry storage
compartment, e.g. of a dryer or a washing machine, a dishwasher
compartment, etc. With alike home appliances the droplet spraying
device is arranged such, that droplets can be sprayed into the
compartment. An alike configured droplet spraying device preferably
sprays liquids or additives, e.g. a fabric finishing additive, a
liquid detergent, a conditioner, a deodorant, a fragrance, a
de-wrinkling agent, a proofing, antibacterial, rinse or softening
agent, etc. into the compartment for appropriate treatment of the
articles to be treated. Such liquids can be stored in or be fed by
a corresponding liquid reservoir and/or the liquid supply
channel.
[0024] For spraying droplets into the compartment the droplet
spraying device may be arranged at a wall section forming part of
the enclosure of the compartment or the droplet spraying device may
be arranged within the compartment. For example, in case of a
dishwasher the droplet spraying device may be arranged at a wall of
the dishes storing compartment and/or at a dishes storing basket.
It may be useful to arrange the droplet spraying device at a
movable element of the home appliance, for example a spray arm of
the same. Such a movable element can be arranged inside the
compartment, for example in case of a dishwasher.
[0025] A compartment may at least partly be formed by a rotatable
drum, e.g. in case of a washing machine or a dryer, in particular a
tumble dryer. The droplet spraying device can be positioned and/or
configured to spray droplets into the drum. Herein the droplet
spraying device may be arranged at a front and/or rear closure
element, the front or rear closure element covering or closing a
front or rear opening of the drum, respectively. Such an
arrangement allows e.g. for easy liquid supply architecture for
supplying liquid to the droplet spraying device.
[0026] Preferably the droplet spraying device is arranged at a
loading door for closing a loading opening and/or be arranged at a
gasket arranged between a loading opening and the compartment. Such
a position enables the feed of additives to the droplet spraying
device by advantageously being able to make use of short liquid
supply channel lengths, especially when liquid is to be supplied
from a liquid reservoir meant to be serviced by a user.
[0027] Alternatively or additionally a droplet spraying device is
arranged in an air flowing channel upstream the compartment,
wherein in particular the air flowing channel is part of a process
air channel and/or part of an air circulation channel. Such an
arrangement allows for introducing mist generated by the droplet
spraying device directly into an air flow towards the compartment,
for example a laundry storage compartment, and in the consequence
for an improved disposition.
[0028] According to an operation method, the home appliance is
operated in a first operation mode and in a second operation mode.
In the first operation mode the vibration frequency and/or speed
and/or the amplitude of the membrane is higher than in the second
mode of operation. In the first operation mode the frequency may
match a resonant frequency of the droplet spraying device for
maintaining resonant vibration.
[0029] In the first operation mode, which in particular is the
droplet generation mode, the membrane sprays the supplied liquid
completely, substantially or at least partially. In a second
operation mode of the droplet spraying device, which in particular
does not spray droplets, the liquid may be completely,
substantially or at least partially flown through the liquid supply
channel and/or the liquid reservoir, e.g. in the direction to an
outlet of the same. In the second operation mode the droplet
spraying device may act as a pump or can for example be
deactivated. In the second operation mode the droplet spraying
device for example may be deactivated and the liquid is flown
through the liquid supply channel and/or the liquid reservoir so as
to flush the membrane. In a pumping mode of operation, which may
correspond with the second operation mode, the droplet spraying
device may for example exert a pumping or sucking force for sucking
liquid into the liquid supply channel and/or the liquid reservoir.
Alternatively or additionally in the second mode of operation the
liquid at the backside of the membrane is pumped out of the droplet
spraying device. For example in this mode the device is acting as a
membrane-like pump.
[0030] According to an embodiment of the method, in a first step
liquid supplied to the membrane is sprayed by the droplet spraying
device, and in a succeeding step (see above first and second
operation modes), the liquid supply channel and/or reservoir are
washed by the liquid previously sprayed or by liquid from another
reservoir or by liquid supplied from a fresh water tap. Such a
further reservoir can for example be a condensed water tank. After
such a washing phase another liquid can be supplied to the membrane
via the liquid supply channel and/or the liquid reservoir.
Consequently, only one liquid supply channel and/or liquid
reservoir in fluid communication with the droplet spraying device
for various liquids, e.g. additives, may be needed.
[0031] Reference is made in detail to preferred embodiments of the
invention, examples of which are illustrated in the accompanying
figures, which show:
[0032] FIG. 1 a schematic view of a dryer with a heat pump
system;
[0033] FIG. 2 a more detailed schematic view of a droplet spraying
device arranged at a component of the heat pump system of the
dryer;
[0034] FIG. 3 a more detailed schematic view of the droplet
spraying device;
[0035] FIGS. 4 to 6 each schematic views of an embodiment in which
a droplet spraying device and a liquid supply is shown in different
arrangements as compared to FIG. 3;
[0036] FIGS. 7a and b exemplary schematic views of the droplet
spraying device, wherein FIG. 7a shows a top view and FIG. 7b
depicts a sectional view;
[0037] FIG. 8 a schematic view of another embodiment of a dryer,
wherein droplet spraying devices are configured to spray droplets
into a compartment or air circulation duct; and
[0038] FIG. 9 a schematic view of another embodiment of the droplet
spraying device having flaps.
[0039] In the following different arrangements of one or more
droplet spraying devices 26 or one or more multiple droplet
spraying devices 27 are disclosed. The arrangement embodiments can
be combined in an arbitrary manner and design aspects relating to
the spraying devices 26/27 and/or its liquid supply 22, 22a, 22b,
24, 24b can be combined or provided with one or more of the other
embodiments. The same reference numerals are used to indicate the
identical or functionally the same function of an element in the
different embodiments.
[0040] FIG. 1 depicts a home appliance 2 where the depicted
embodiment is a tumble dryer, especially a heat pump tumble dryer.
A tumble dryer of this kind is generally well known in the art and
comprises a heat pump system 4, including a heat exchanger device
having a vaporizer or evaporator 6, a condenser 8, a compressor 10
and an expansion device 12 (for example a capillary tube 12). The
process air flow within the heat pump system 4 is guided through a
compartment 14 of the home appliance 2, i.e. through a compartment
14 for articles to be treated, e.g. a drum 14, wherein the airflow
within a process air channel for circulating the air is depicted by
arrows A in FIG. 1. The articles to be treated are textiles or is
laundry. In case the home appliance is a dishwasher, the articles
are dishes or the like.
[0041] The heat exchanger device 6 of the dryer 2 is endangered of
being soiled or clogged by fluff transported out of the compartment
14 with the process air flow. Although fluff filters 16 are
arranged in the flow path, for example at an outlet 18 of the
compartment 14, fine particles still are comprised within the air
leaving the compartment 14. To avoid clogging or reduction in
efficiency, the heat exchanger device 6 of the home appliance 2 is
cleaned or washed regularly as explained below.
[0042] For washing the heat exchanger device 6 condensed water
generated in the heat pump cycle, i.e. at surfaces of the
evaporator 6, can advantageously be used. Such condensed water is
collected in a collector device 20, e.g. in a collector tray or
collector tank 20. Therefrom it can e.g. be fed to a condensate
tank 21, a liquid reservoir 22 and/or a liquid supply channel 24,
which are provided to supply water to a droplet spraying device 26.
The condensed water from the collector device 20 can be conveyed by
means of a pump 28 and/or a suitable duct structure 30 to the tank
21, the reservoir 22 and/or the channel 24. Pump 28 can e.g. be
automatically operated when triggered by a switch signal from a
float switch 32.
[0043] FIGS. 2 to 6 each exemplarily visualize schematic details of
the dryer 2. The heat exchanger 6, in particular at least one
surface thereof, and further in particular a heat exchanging
surface thereof, is to be cleaned by a droplet spraying device 26.
The heat exchanger 6 depicted is an evaporator 6 of the dryer 2
with a heat pump system 4 as described above, but may generally be
any heat exchanger device 6 in need of cleaning, e.g. in a dryer or
a washing machine with drying function.
[0044] In FIGS. 2 to 6 the heat exchanger 6 is arranged in a
section of an air circulation channel 4a, which in particular is
part of the process air channel defined within the dryer 2. The air
supply channel 4a is meant for guiding process air (indicated by
arrows A) through at least a portion of the heat pump system 4. In
the air supply channel 4a downstream the heat pump system 4 a fan
34 may be arranged, FIG. 2. Furthermore, as depicted in FIGS. 2 and
3, a filter element 16, may be arranged at an inlet of the air
supply channel 4a, upstream the heat pump system 4. The collector
device 20 collects condensed water from the heat exchanger 6 for
feeding it to the droplet spraying device 26. In the embodiment of
FIG. 1 the condensed water is supplied to the device 26 via
condensate line 30, condensate tank 21, liquid supply channel 24
and liquid reservoir 22 (FIG. 2).
[0045] The droplet spraying devices 26 shown in FIGS. 2 to 6 each
comprise a membrane 36 with a plurality of openings 38 and at least
one actuator 40 for actuating the membrane 36, as for example is
exemplified in FIGS. 7a and 7b. A droplet spraying device 26 can
comprise e.g. a first annulus 42, known as "invar" which for
example is formed of nickel-iron alloy. Bonded to the annulus 42
may be a second, in particular piezoelectric annulus 44 as well as
the perforate membrane 36, in particular a circular membrane 36. On
top of the second annulus 44 a driving electrode 46 can be formed.
By applying a voltage, for example a sinusoidal voltage, to the
first annulus 42 and the driving electrode 46, the actuator 40
comprising the first 42 and second annulus 44 and the electrode
structure 46 can be actuated, whereupon the membrane 36 is put to
vibration. It shall be noted, that in FIG. 7b a liquid reservoir 22
in fluid connection with the membrane 36 is exemplified by the
dotted line.
[0046] As for example depicted in FIGS. 3 and 4, the droplet
spraying device 26, in particular its membrane 36, is arranged such
that droplets emerging from a front side of the membrane 36 can be
sprayed onto the heat exchanger surface to be cleaned. For an
enhanced spraying capability multiple droplet spraying devices 26
may be arranged within the home appliance 2. Each droplet spraying
device 26 of a such multiple droplet spraying device 27 includes a
membrane 36 in direct fluid connection with the liquid reservoir 22
(FIG. 3) or the liquid supply channel 24 (FIG. 4), wherein fluid is
supplied to a backside of the membrane 36 and in operation droplets
emerge from a front side, indicated by arrows B.
[0047] In the embodiments of FIGS. 2 and 3 the droplet spraying
device 26 forms a walls section of the liquid reservoir 22.
[0048] The liquid reservoir 22 contains the liquid to be sprayed by
the droplet spraying devices 26, e.g. condensed water supplied from
the collecting device 20, water from tap, liquid fed by a user,
etc. The liquid is fed through an inlet 22a to the liquid reservoir
22. The liquid reservoir 22 can further have an outlet 22b for
emptying the reservoir 22, e.g. by making use of a pumping action
of the droplet spraying device 26 or for flushing the reservoir 22
in the context of cleaning the same. The outflow of liquid through
the outlet 22b can be controlled by a valve shown in FIG. 2, which
is generally closed and can be opened by demand. Alternatively or
additionally, the liquid reservoir 22 can have an outlet 22b
comprising a level drain as shown in FIG. 3. Liquid drained out of
the liquid reservoir 22 via outlet 22b is indicated by arrow C and
may also be collected by the collecting device 20 for further use
or can be drained away.
[0049] Here the droplet spraying devices 26 are situated bordering
the liquid reservoir 22. In doing so no further liquid supply means
for feeding fluid from the liquid reservoir 22 to the membrane 36
is necessary. A suitable liquid reservoir 22 can hereby be designed
with a small frame.
[0050] To establish a fluid connection between the droplet spraying
device 26 and the liquid reservoir 22, the membrane 36 can span a
cut-out or through-hole established in the wall of the liquid
reservoir 22 such that liquid contained within the reservoir 22
contacts the membrane 36, i.e. its backside. The membrane 36 can be
situated within a corresponding through-hole, e.g. at the bottom of
or within the wall structure of the liquid reservoir 22 or next to
a port of such a through hole. Herein also the actuator 40 can be
arranged in such a manner. In such an arrangement the membrane 36
seals the cut-out or through-hole if not actuated.
[0051] In FIGS. 2 and 3 the droplet spraying device 26, in
particular together with the liquid reservoir 22, is situated at a
structural part of the home appliance 2 neighboring the component 6
to be sprayed upon. The arrangement, in particular close to the air
supply channel 4a for flowing air to the heat exchanging device 6,
is such that droplets can be sprayed onto the evaporator 6. In an
advantageous arrangement the droplet spraying device 26, in
particular together with the liquid reservoir 22 (and/or a liquid
supply channel 24), is positioned above the heat exchanger 6 such
that droplets to be sprayed can additionally be accelerated by
gravity. The term `above` relates to the operational orientation of
the home appliance (here dryer 2).
[0052] Advantageously the droplet spraying devices 26, in
particular the multiple droplet spraying device 27, are formed
integrally with the liquid reservoir 22 and/or a liquid supply
channel 24, i.e. as a single module. By doing so the at least one
droplet spraying device 26 (e.g. a plurality of devices 26 in the
multiple spray device 27) can be mounted easily, i.e. via mounting
the liquid reservoir 22 or a liquid supply channel 24 at the
predetermined position, respectively.
[0053] FIGS. 4 to 6 each exemplarily depict a liquid supply to the
droplet spraying devices 26 and its membrane 36, respectively,
wherein each membrane 36 is in fluid communication with the liquid
supply channel 24. The supply channel 24 can be fluid connected to
a line 30 in fluid connection with the collector device 20 (FIG.
4), or be fluid connected to the liquid reservoir 21 or 22 (FIGS. 5
and 6) or generally be fluid connected to a liquid source.
[0054] In FIG. 4 downstream of an inlet 24a a supply line for
example branches into one liquid supply channel 24 per membrane 36
such that liquid can be supplied individually to each device
26/membrane 36. A liquid supply channel 24 hereby acts as a liquid
reservoir 22. For example it is designed to provide liquid by a
capillary action, e.g. in cooperation with the actuated membrane
36. The droplet spraying devices 26 depicted in FIG. 4 are situated
on a structural part of the home appliance 2 (dryer) neighboring
the evaporator 6, the arrangement enabling them to spray droplets
onto the evaporator 6 to be cleaned.
[0055] In FIG. 5 a liquid supply channel 25 connects to liquid
reservoir 22, wherein the multiple droplet spraying device 27 is
fed by only one liquid supply channel 25, i.e. a common liquid
supply channel 25. By supplying liquid to multiple droplet spraying
device 27 via a single supply channel 25, only little financial
effort for supplying liquid is necessary. FIG. 5 further shows
situating the droplet spraying devices 26 inside the air supply
channel 4a neighboring the surface area of the evaporator 6 to be
cleaned. By situating the droplet spraying devices 26 inside the
air supply channel 4a, the spray effect can especially be focused
to an area where most deposits (fluff) are to be expected.
[0056] FIG. 6 shows a related arrangement, wherein the droplet
spraying devices 26 are arranged upstream of the evaporator 6. The
spray direction of the droplet spraying devices 26, arrow B, hereby
in particular matches the direction of the processing air flow,
arrows A, such that a spray effect can be enhanced by the
processing air flow.
[0057] It is to be noted that FIGS. 3 and 4 further exemplify a
driving structure 48 for one or more actuators 40. Such a driving
structure 48 may comprise a low-voltage (AC) circuit, e.g.
providing for actuation of multiple or all actuators 40 at once,
e.g. by making use of a bus bar, or allowing for separate actuation
of selected ones or each individual actuator 40. Driving structure
48 or at least part of it may be integrated in or on the liquid
reservoir 22 and/or part of the liquid supply channel 24, e.g.
printed or arranged thereon. The driving structure 48 may be
controlled by an overall control device of the home appliance 2
(dryer) and/or comprise a stand-alone functionality. A control
function can be implemented enabling the actuating of a selected
one or a group of the droplet spraying devices 26 out of a
plurality thereof in the multiple droplet spraying device 27, FIGS.
5 and 6.
[0058] FIG. 8 further depicts dryer 2 in another embodiment,
wherein droplet spraying devices 26 spray droplets into the
compartment 14 for articles to be treated. The dryer 2 can
generally be a home appliance like a dishwasher or a laundry
treatment apparatus, for example a laundry treatment apparatus with
washing and/or drying function. The compartment 14 can be a laundry
storage compartment 14 in case of the home appliance 2 being a
washing machine and/or a dryer, e.g. a drum, or a dishes storing
compartment 14 in case of a dish washer, i.e. a non-rotatable
compartment 14. Such a home appliance 2 can also include a droplet
spraying device 26 for purposes described above in connection with
FIGS. 1 to 7b.
[0059] The dryer 2 of FIG. 8 is adapted to spray droplets into the
compartment 14 by a droplet spraying device 26 (or a multiple
droplet spraying device 27 not depicted in FIG. 8). Such droplets
can be droplets build up from various kinds of liquids, comprising
one or more of: water, a liquid detergent, conditioner, deodorant,
fragrance or de-wrinkling agent and a proofing, antibacterial,
rinse or softening agent. For storing such liquids the home
appliance 2 can comprise one or more suitable liquid reservoirs 22,
especially such, which are meant to be filled by a selected liquid
by a user. The articles to be treated within the compartment 14 are
brought in interaction with the respective kind of liquid supplied
to the droplet spraying device 26. Each droplet spraying device 26
(its membrane 36) is in fluid communication with the liquid supply
channel 24 and/or the liquid reservoir 22.
[0060] To supply liquids into the compartment 14 by spraying
droplets the droplet spraying device 26 in particular is arranged
at a wall section 50 forming part of the enclosure of the
compartment 14. Such a wall section 50 may be a stationary part of
the compartment 14 not rotating with and closing the openings of
the rotatable drum 52. For example the stationary part is a rear
closure element 54 of drum 52, FIG. 7. If the home appliance is a
dishwasher the droplet spraying device 26 can also be arranged at
any section of the stationary wall of the dishwasher tub.
[0061] FIG. 8 also exemplarily depicts the arrangement of a droplet
spraying device 26 neighboring a loading opening 56 of the
compartment 14. Herein the droplet spraying device 26 is arranged
such that droplets can be sprayed through the loading opening 56 of
the drum 52 into the compartment 14. Appropriate positions for such
an arrangement of the droplet spraying device 26 are for example a
loading door 58 of the home appliance 2, a gasket arranged between
the loading opening 56 and the compartment 14, and/or a stationary
frame between the loading opening and the drum.
[0062] Another droplet spraying device 26 is arranged in an air
flowing channel 60 upstream the compartment 14. In FIG. 8 air
flowing channel 60 is part of a closed loop process air channel
and/or part of an air circulation channel for air circulation
within the dryer 2 (arrows A indicate the air flow). With such an
arrangement a uniform distribution of the droplets with respect to
their distribution over the articles to be treated can be achieved,
as the droplets can be easily carried throughout the compartment 14
by the air flow entering or passing through the compartment, arrows
A. In other embodiments not shown, the dryer or washing machine can
be of the exhaust process air type where ambient air is flown over
a e.g. cross-flow) heat exchanger element and thereafter is
exhausted to the outside of the home appliance.
[0063] FIG. 8 also depicts a valve 62, which e.g. may be installed
in a liquid supply channel 24 for controlling liquid supply to the
droplet spraying device 26. Additionally or alternatively a pump 64
for liquid supply is provided. A control device 66 for controlling
one or more droplet spraying devices 26 via control line 68 is
implemented.
[0064] FIG. 9 shows another exemplary embodiment of the droplet
spraying device that can be used in any of the above configurations
of FIGS. 1 to 8. In this embodiment a first flap 72 is arranged at
the inlet 22a and a second flap 70 is arranged at the outlet 22b of
the liquid reservoir 22 (or the section of the liquid supply
channel 24 where the droplet spraying device 26 is arranged in the
alternative configuration). In a first operation mode of the device
26 the frequency of the voltage applied by driving structure 48 is
high and correspondingly the vibration frequency of membrane 36 is
high while its stroke D is low. At high frequency of the membrane
36 liquid droplets overcome the capillary or surface force of the
openings 38 onto the liquid and droplets separate from the
membrane's outside surface establishing spraying activity. Inlet
flap 72 takes an intermediate position between opening and closing
such that liquid is sucked into the inner volume of reservoir 22
(or channel section 24). In this first operation mode, ideally,
outlet flap 70 is closed or nearly closed so that no or little
fluid drains through outlet 22b (comparable to cardiac
fibrillation).
[0065] In a second mode of operation the driving frequency is
lower, thus the vibration frequency of the membrane 36 is lower and
its stroke D is larger. Due to the lower vibration frequency,
droplets do not release from the openings 38 and no liquid is
sprayed. Instead a heart-like pumping activity is provided by the
membrane and the liquid is pumped through the outlet 22b. Thus
there is a liquid flow through the reservoir 22 (or the device
section of channel 24). The liquid flow flushes away any deposits
(e.g. fluff or scale) that may have collected in the reservoir (or
in the channel 24/25 section), in particular on the membrane 36 and
its openings 38.
TABLE-US-00001 Reference Numeral List: 2 home appliance 4 heat pump
system 4a air channel 6 evaporator (component) 8 condenser 10
compressor 12 expansion device 14 compartment 16 fluff filter 18
outlet 20 collector device 21 condensate tank 22 liquid reservoir
22a inlet 22b outlet 24 liquid supply channel 24a inlet 25 liquid
supply channel 26 droplet spraying device 27 multiple droplet
spraying device 28 pump 30 condensate line 32 float switch 34 fan
36 membrane 38 opening 40 actuator 42 first annulus 44 second
annulus 46 driving electrode 48 driving structure 50 wall section
52 drum 54 rear closure element 56 loading opening 58 loading door
60 air flowing channel 62 valve 64 pump 66 control device 68
control line 70 outlet flap 72 inlet flap A airflow (arrow) B
Droplets C liquid from outlet 22b (arrow) D membrane stroke
length
* * * * *