U.S. patent application number 12/255150 was filed with the patent office on 2009-04-23 for low-water-consumption rinsing and/or washing device, and dishwashing machine featuring such a device.
This patent application is currently assigned to Premark FEG L.L.C.. Invention is credited to Gianluca Pardini.
Application Number | 20090101185 12/255150 |
Document ID | / |
Family ID | 40120062 |
Filed Date | 2009-04-23 |
United States Patent
Application |
20090101185 |
Kind Code |
A1 |
Pardini; Gianluca |
April 23, 2009 |
LOW-WATER-CONSUMPTION RINSING AND/OR WASHING DEVICE, AND
DISHWASHING MACHINE FEATURING SUCH A DEVICE
Abstract
A spray arm assembly for a dishwashing machine includes at least
one arm rotationally mounted about an axis, the arm including an
internal cavity for receiving a pressurized service fluid and being
provided with a plurality of spraying nozzles for spraying service
fluid from said arm in the form of spray jets. The arm is shaped so
that its opposite ends radially extend from the rotation axis in a
manner diametrically opposite to each other about the rotation
axis. The spraying nozzles are numbered, sized and positioned such
that a total flow rate of service fluid delivered in use by the
spraying nozzles at each concentric nozzle location circumference
traced about the rotation axis of the arm during a complete
rotation of the arm increases as a function of the radius of said
nozzle location circumference.
Inventors: |
Pardini; Gianluca; (Via
Boboli, IT) |
Correspondence
Address: |
THOMPSON HINE LLP;Intellectual Property Group
P.O Box 8801
DAYTON
OH
45401-8801
US
|
Assignee: |
Premark FEG L.L.C.
Wilmington
DE
|
Family ID: |
40120062 |
Appl. No.: |
12/255150 |
Filed: |
October 21, 2008 |
Current U.S.
Class: |
134/179 ;
134/172 |
Current CPC
Class: |
A47L 15/23 20130101 |
Class at
Publication: |
134/179 ;
134/172 |
International
Class: |
A47L 15/22 20060101
A47L015/22; A47L 15/23 20060101 A47L015/23 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 23, 2007 |
IT |
TO 2007-A-000753 |
Claims
1. A rinsing and/or washing device for a dishwashing machine,
comprising at least one arm rotationally mounted about a generally
vertical axis (A) in a washing chamber of the dishwashing machine,
the arm delimiting a cavity therein connected in use to delivering
means of a pressurized service fluid and being provided with a
plurality of spraying nozzles arranged and oriented, in use, for
spraying towards dishes to be washed, the spraying nozzles spaced
along a length of the arm and communicating with the internal
cavity (22) of the arm, so as to determine in use exiting of
service fluid from the arm in form of jets directed against dishes;
wherein said arm is shaped so that its opposite ends radially and
overhangingly extend from the rotation axis, in a manner
diametrically opposite to the rotation axis itself; characterized
in that, in combination, the number, the size and the position of
the spraying nozzles is such that the total flow rate of service
fluid delivered in use by the spraying nozzles at each concentric
nozzle location circumference traced about the rotation axis of the
arm during a complete rotation of the arm is an increasing function
of the radius of said nozzle location circumference.
2. A device according to claim 1, characterized in that the total
flow rate of service fluid delivered in use by the spraying nozzles
at each concentric nozzle location circumference traced about the
rotation axis of the arm during the complete rotation of the arm
increases in an essentially linear manner with the radius of said
nozzle location circumference.
3. A device according to claim 2, characterized in that said arm
has an assembly portion for securing it to said rotation axis
arranged essentially on the middle line of the arm, so that
opposite longitudinal portions of the arm, provided with said
spraying nozzles and ending with said opposite ends of the arm,
protrude in use in an essentially symmetric manner from the
assembly portion in radial direction with respect to the rotation
axis.
4. A device according to claim 3, characterized in that said
spraying nozzles are arranged along said opposite longitudinal
portions of the arm so that at least one spraying nozzle of a first
of said opposite longitudinal portions of the arm is arranged in a
radially symmetric position with respect to at least one spraying
nozzle of a second of said longitudinal portions of the arm, so
that said at least one spraying nozzle of said first longitudinal
portion of the arm traces in use the same nozzle location
circumference traced in use by said at least one spraying nozzle of
said second longitudinal portion of the arm.
5. A device according to claim 4, characterized in that said arm is
provided with first spraying nozzles adapted to deliver in use a
first predetermined flow rate of service fluid; and with second
spraying nozzles adapted to deliver in use a second predetermined
flow rate of service fluid, smaller than said first predetermine
flow rate.
6. A device according to claim 5, characterized in that said arm is
provided only with said first and second spraying nozzles.
7. A device according to claim 6, characterized in that the first
of said opposite longitudinal portions of the arm carries one
second spraying nozzle arranged at a predetermined radial distance
from the assembly portion so as to trace in use a first nozzle
location circumference about said rotation axis, and a pair of
first spraying nozzles arranged in tandem at respective radial
distances from the assembly portion so that each of them
respectively traces in use a second and a third nozzle location
circumference about said rotation axis.
8. A device according to claim 7, characterized in that the second
longitudinal portion of the arm, opposite to the first, carries:
one first spraying nozzle arranged at a radial distance from the
assembly portion so as to trace in use a fourth nozzle location
circumference about said rotation axis; one second spraying nozzle
arranged at a radial distance from the assembly portion so as to
trace in use said second nozzle location circumference about said
rotation axis; and one first spraying nozzle arranged at a radial
distance from the assembly portion so as to trace in use said third
nozzle location circumference about said rotation axis.
9. A device according to claim 8, characterized in that said fourth
nozzle location circumference has a radius greater than that of
said first nozzle location circumference and smaller than the
radius of said second nozzle location circumference.
10. A device according to claim 9, characterized in that said arm
is provided with reaction thrust generating means to determine in
use the rotation about said axis.
11. A spray arm assembly for a dishwashing machine, comprising at
least one arm rotationally mounted about an axis, the arm including
an internal cavity for receiving a pressurized service fluid and
being provided with a plurality of spraying nozzles for spraying
service fluid from said arm in the form of spray jets; wherein said
arm is shaped so that its opposite ends radially extend from the
rotation axis in a manner diametrically opposite to each other
about the rotation axis; characterized in that, the spraying
nozzles are numbered, sized and positioned such that a total flow
rate of service fluid delivered in use by the spraying nozzles at
each concentric nozzle location circumference traced about the
rotation axis of the arm during a complete rotation of the arm
increases as a function of the radius of said nozzle location
circumference.
12. The spray arm assembly according to claim 11, characterized in
that the total flow rate of service fluid delivered in use by the
spraying nozzles at each concentric nozzle location circumference
traced about the rotation axis of the arm during the complete
rotation of the arm increases in an essentially linear manner with
the radius of said nozzle location circumference.
13. The spray arm assembly according to claim 12, characterized in
that said arm has a central assembly portioned for securing it to a
dishwashing machine, said rotation axis extending through said
central assembly so that opposite longitudinal portions of the arm,
provided with said spraying nozzles and ending with said opposite
ends of the arm, protrude in use in an essentially symmetric manner
from the assembly portion in radial direction with respect to the
rotation axis.
14. The spray arm assembly according to claim 13, characterized in
that said spraying nozzles are arranged along said opposite
longitudinal portions of the arm so that at least one spraying
nozzle of a first of said opposite longitudinal portions of the arm
is arranged in a radially symmetric position with respect to at
least one spraying nozzle of a second of said longitudinal portions
of the arm, so that said at least one spraying nozzle of said first
longitudinal portion of the arm traces in use the same nozzle
location circumference traced in use by said at least one spraying
nozzle of said second longitudinal portion of the arm.
15. The spray arm assembly according to claim 14, characterized in
that said arm is provided with first spraying nozzles adapted to
deliver in use a first predetermined flow rate of service fluid;
and with second spraying nozzles adapted to deliver in use a second
predetermined flow rate of service fluid, smaller than said first
predetermine flow rate.
16. The spray arm assembly according to claim 15, characterized in
that the first of said opposite longitudinal portions of the arm
carries: one second spraying nozzle arranged at a predetermined
radial distance from the assembly portion so as to trace in use a
first nozzle location circumference about said rotation axis, and a
pair of first spraying nozzles arranged in tandem at respective
radial distances from the assembly portion so that each of them
respectively traces in use a second and a third nozzle location
circumference about said rotation axis.
17. A device according to claim 16, characterized in that the
second longitudinal portion of the arm, opposite to the first,
carries: one first spraying nozzle arranged at a radial distance
from the assembly portion so as to trace in use a fourth nozzle
location circumference about said rotation axis; one second
spraying nozzle arranged at a radial distance from the assembly
portion so as to trace in use said second nozzle location
circumference about said rotation axis; and one first spraying
nozzle arranged at a radial distance from the assembly portion so
as to trace in use said third nozzle location circumference about
said rotation axis.
18. A device according to claim 17, characterized in that said
fourth nozzle location circumference has a radius greater than that
of said first nozzle location circumference and smaller than the
radius of said second nozzle location circumference.
19. A dishwashing machine including the spray arm assembly of claim
11, comprising: a wash chamber including a dish receiving area; the
spray arm assembly of claim 11 mounted for rotation within the wash
chamber with the rotation axis essentially vertical; a service
fluid delivery system connected to deliver service fluid to the
internal cavity of the arm.
20. The dishwashing machine of claim 19 wherein the spray arm
assembly is fluid-tightly mounted on an inlet head within the
washing chamber.
Description
TECHNICAL FIELD
[0001] The present application relates to a rinsing and/or washing
device for an electric household appliance, specifically for a
dishwashing machine of the professional type, able to drastically
reduce the consumption of water. The application further relates to
the electric household appliance equipped with such a device.
BACKGROUND
[0002] A washing/rinsing device for a dishwashing machine including
a rotating arm provided with spraying nozzles and epicyclic
movement in order to perform a better distribution of
washing/rinsing fluid inside the washing chamber of the dishwashing
machine, usually accessible through a front pivoting door, is known
from EP1050263.
[0003] However, the known device, in addition to be costly and
complex to be manufactured, has considerable dimensions and in any
case does not solve the problem of drastically reducing the amount
of water needed by the machine for carrying out the washing cycle
and, in particular, the rinsing cycle, simultaneously obtaining
good washing results on the dishes to be treated.
[0004] Indeed, a study internally carried out by the Applicant has
recently brought to light that all the dishwashing machines
manufactured nowadays, in order to ensure a "minimum guaranteed"
delivery of water in all points of the washing chamber, deliver
more water than needed in many points of the chamber itself. This
drawback causes a considerable waste of water resources and, above
all, of energy resources, in particular in dishwashing machines for
professional use (for bars, restaurants, communities, etc.) which,
even if largely work with recirculated water (closed cycle), must
however resort to the water from the water network (open cycle) at
least for the rinsing cycle and, in all cases, must heat the
washing and rinsing water before delivering it onto the dishes at
relatively high temperatures for hygienic reasons.
[0005] It would be desirable to provide an improved rinsing and/or
washing device for an electric household appliance, in particular a
dishwashing machine for professional use, which overcomes the
aforesaid drawbacks, allowing a high reduction of water and energy
consumptions of the dishwashing machine, in particular during the
rinsing cycle, and at the same time, which is simple and cost
effective to be manufactured and managed, of reduced size and high
reliability, in particular with regards to possible obstructions in
use of the water delivering jets. It would also be desirable to
provide a dishwashing machine provided with such a device which,
therefore, has reduced energy and water consumptions.
SUMMARY
[0006] In one aspect, a rinsing and/or washing device for an
electric household appliance, in particular a dishwashing machine,
is thus provided as defined in claim 1.
[0007] In particular, a device comprises at least one arm
rotationally mounted about a generally vertical axis in a washing
chamber of the electric household appliance, e.g. immediately
either over or under a container basket of the dishes to be washed.
The arm delimits a cavity therein connected in use to delivering
means of a pressurized service fluid, e.g. a washing and/or rinsing
fluid, of the electric household appliance and is provided with a
plurality of spraying nozzles arranged and oriented, in use,
towards the dishes to be washed, reciprocally spaced in the
direction of length of the arm and communicating with the internal
cavity of the latter, so as to determine in use the exiting of the
service fluid from the arm in form of jets directed against the
dishes.
[0008] The arm is shaped so that its opposite ends radially and
overhangingly extend from the rotation axis, in a manner
diametrically opposite to the rotation axis itself, according to a
configuration which is generally known; however, in combination
with such a feature, the number, the size and the position of the
existing nozzles are chosen so that the total flow rate of the
service fluid delivered in use by the nozzles present on the arm at
each concentric circumference that the same nozzles trace about the
rotation axis of the arm during a complete rotation of the same is
an increasing function, in particular linearly increasing, of the
radius of such a circumference.
[0009] In this manner, the zones of the basket closest to the
rotation axis of the arm are reached by less water, while more
water is directed towards the furthermost zones, to reach which the
nozzles of the arm, during the rotation of the same, must cover a
larger area and, thus, must necessarily have a lower water delivery
"density" (ml/cmq), with the flow rate being equal. By
appropriately balancing the flow rates during the design of the arm
and of the nozzles thereof, it is thus possible to obtain an
essentially constant water delivery "density" throughout the
dish-holding basket. Assuming to always use the minimum amount of
water deemed sufficient to obtain adequate cleaning results
(approximately 2.7 litres per basket), simple calculations allow to
establish that by means of the device of the invention a saving of
water, which may reach even 30% in the rinsing cycle, may be
obtained, with a consequent, drastic reduction of water
consumptions and, above all, of energy consumptions of the
dishwashing machine equipped with such a device.
[0010] In one implementation, the arm is provided with only two
types of nozzles, namely with first nozzles, adapted to deliver in
use a first predetermined flow rate of service fluid, and second
nozzles adapted to deliver in use a second predetermined flow rate
of service fluid, lower than the first flow rate; and the nozzles
are arranged along opposite longitudinal portions of the arm, which
extend radially and overhangingly from a central securing portion
of the arm to the rotation axis of the same so that at least one
nozzle of a first of the opposite longitudinal portions of the arm
is arranged in a radially symmetric position with respect to at
least one nozzle of a second of the opposite longitudinal portions
of the arm, so as to trace in use the same circumference traced in
use by the nozzle of the second longitudinal portion of the arm and
therefore may add this to its own water flow rate.
[0011] In this manner, it is possible to obtain the desired water
distribution with only two types of different nozzles (instead of
with a plurality of nozzles of progressively increasing flow rate
arranged at progressively increasing distances from the rotation
axis), as long as these are appropriately positioned in an
asymmetric manner along the arm so that, for certain circumferences
they trace in use, the flow rates delivered thereby are
appropriately added, while for other circumferences this does not
occur. On one hand, this implies a drastic reduction of production
and assembly costs of the washing device according to the invention
and, on the other hand, avoids the risk that nozzles of excessively
small flow rate (thus with a reduced water passage section) may be
obstructed in use due to the dirt which is removed from the
dishes.
BRIEF DESCRIPTION OF DRAWINGS
[0012] Further objects and advantages will be apparent from the
following description of a non-limitative embodiment thereof,
provided only by way of example and with reference to the figures
of the accompanying drawing, in which:
[0013] FIG. 1 diagrammatically shows a perspective view of a
dishwashing machine provided with a washing device manufactured
according to the invention;
[0014] FIG. 2 diagrammatically shows a side elevation view of the
washing device used in the dishwashing machine in FIG. 1 compared
to a graph which provides for the distribution of the
washing/rinsing water obtainable according to the invention;
and
[0015] FIG. 3 diagrammatically shows a bottom plan view of the
washing device in FIGS. 1 and 2.
DETAILED DESCRIPTION
[0016] In figures from 1 to 3, numeral 1 indicates as a whole a
rinsing and/or washing device for an electric household appliance
2, in particular a dishwashing machine for professional use, of the
front loading type in the example shown.
[0017] The dishwashing machine 2 comprises in particular a washing
chamber 3 accommodating at least one container basket 4 (known) for
the dishes 5 to be washed, the washing device 1 and delivering
means 7 of a pressurised service fluid 8, e.g. washing and/or
rinsing water, towards the device 1, in this case towards an inlet
head 10 arranged in the washing chamber 3 with its own symmetry
axis A arranged essentially vertical and connected to the
washing/rinsing device 1 in the manner disclosed below.
[0018] The delivering means 7 of the pressurized water are known
and comprise, in this case, a pump 11, a tank 12 in which the water
delivered onto the dishes 5 through the inlet head 10 and the
device 1 is collected in use, and network water feeding means 13,
the pump 11 being able to use both the network water and the water
in the tank 12.
[0019] The device 1 comprises at least one arm 20 rotationally
mounted about axis A, which is generally vertical, within the
washing chamber 3 of the electric household appliance 2, e.g. in a
preferred embodiment, immediately over (or under) the container
basket 4, in this case, idly and fluid-tightly mounted in a known
manner and thus not described in detail for simplicity, on the
inlet head 10 with its own central assembly portion 21.
[0020] The arm 20 delimits therein a cavity 22 (FIG. 3) connected
in use to the delivering means 7 of the water through the inlet
head 10 and is provided with a plurality of spraying nozzles 23
arranged oriented in use towards the dishes 5 to be washed,
reciprocally spaced in the sense of length of the arm 20 and
communicating with the internal cavity 22 of the latter, so as to
determine in use the exiting of the service fluid 8 (water or water
and detergent) from arm 20 in the form of jets 24 (FIG. 2) directed
towards the dishes 5.
[0021] In accordance with the description, the arm 20, according to
a first aspect of the invention, is shaped so that its opposite
ends 25,26 radially and overhangingly extend, in use, from rotation
axis A in a manner diametrically opposite with respect to the
rotation axis A itself; in combination with such a feature, the arm
20 is constructed so that the number, the size and the position of
the existing nozzles 23 is such that the total flow rate of the
service fluid 8 delivered in use by the nozzles 23 at each ideal
concentric nozzle location circumference C (diagrammatically shown
with a dashed line in FIG. 3) which is traced by the nozzles 23
themselves about the rotation axis A of the arm 20 during a
complete rotation of the same, is an increasing function of the
radius of such a circumference.
[0022] Specifically, the total flow rate of the service fluid 8
delivered in use by the nozzles 23 at each concentric nozzle
location circumference C which they trace about the rotation axis A
of the arm 20 during a complete rotation of the same, increases in
an essentially linear manner with the radius of the circumferences
C, as diagrammatically shown in the graph in FIG. 2.
[0023] Substantially, according to the invention, the arm 20 is
designed to deliver by means of the nozzles 23 more water the
farther the distance of the nozzles 23 from the rotation axis A is.
Such a result might be obtained by an arm however shaped and
mounted, provided that it is equipped with nozzles of gradually
larger opening according to their distance from the rotation axis
A; however, in such a manner, the manufacturing cost of the arm 20
would be relatively high and, above all, the opening of the nozzles
closest to the axis A would be so small that they risk being
obstructed in use by the dirt removed from the dishes 5.
[0024] Therefore, according to a non negligible aspect of the
invention, the assembly portion 21 to the inlet head 10, known per
se, is essentially arranged on the middle line of the arm 20, so as
to split the arm into two opposite longitudinal portions 27,28,
which are the only parts of the arm 20 provided with the nozzles
23; the portions 27,28 end, on the opposite side of the assembly
portion 21, with the ends 25,26, which may be provided (FIG. 3)
with propulsion nozzles 30 (known per se) appropriately oriented
and constructed so as to determine a tangential pouring of service
fluid 8 therethrough, so that the nozzles 30 represent in use
reaction thrust generating means for determining the rotation of
the arm 20 about the axis A.
[0025] Alternatively, the nozzles 30 may be missing and therefore
the nozzles 23 (according to a method which is known per se) will
be oriented slightly askew with respect to axis A, so as to further
determine in use, by means of the ejection from the washing/rinsing
jets 24, the reaction rotation movement of the arm 20 about the
axis A.
[0026] In this manner, the assembly portion 21 serves the two-fold
function of securing, in use, the arm 20 to the rotation axis A so
that the longitudinal portions 27,28 protrude in use in an
essentially symmetric manner from the assembly portion 21 in a
radial direction with respect to the rotation axis A; and of making
the fluid-tight connection between the inlet head 10 and the
corresponding delivering means 7 of the service fluid 8 and the
internal cavity 22 of the arm 20. The latter is obtained either by
manufacturing the portions 27,28 as tubular elements closed at the
ends 25,26, or by manufacturing the portions 27,28 by means of two
reciprocally coupled concave parts (e.g. made of pressed metal
sheet).
[0027] In combination with the structure of the arm 20 described
heretofore, the nozzles 23 are arranged along the opposite
longitudinal portions 27,28 of the arm 20 so that at least one
nozzle 23 of the portion 27 is arranged in a radially symmetric
position with respect to at least a corresponding nozzle 23 of the
portion 28, so that these two nozzles 23 trace in use the same
circumference C, therefore adding their flow rates of service fluid
8 towards the basket 4, meaning that the jets 24 produced therefrom
will insist, in use, on the same area (in this case, defined by a
circular crown centred on axis A) of the basket 4.
[0028] According to a preferred but not limitative embodiment of
the invention, the arm 20 is provided with only two different types
of nozzles 23, namely with nozzles 23b adapted to deliver in use a
first predetermined flow rate q1 of fluid 8, and with nozzles 23c
adapted to deliver in use a second predetermined flow rate q2 of
service fluid 8, smaller than the flow rate q1 (the relation
q1>q2 thus applies).
[0029] The nozzles 23b and 23c are further arranged according to an
asymmetric configuration with respect to axis A so as to generate
in use, with the nozzles 23b and 23c of the portion 27, jets 24
which may be added (meaning that they insist on the same areas of
the basket 4 in use) or not, to the jets 24 generated by the
nozzles 23b and 23c of the portion 28.
[0030] In particular, the longitudinal portion 27 of the arm 20
carries a nozzle 23c arranged at a predetermined radial distance
from the assembly portion 21 so as this traces in use a first
circumference C1 of radius R1 about the rotation axis A, and a pair
of nozzles 23b arranged in tandem at a radial distance from the
assembly portion 21 so that each of them traces in use a second
circumference C2 of radius R2 greater than R1 and a third
circumference C3 of radius R3 greater than R2 about the rotation
axis A, respectively.
[0031] The opposite longitudinal portion 28 of the arm 20 instead
carries a nozzle 23b arranged at a radial distance from the
assembly portion 21 so that this traces in use a fourth
circumference C4 of radius R4 about the rotation axis A; gradually
moving away from axis A, there is a second nozzle 23c arranged at a
radial distance from the assembly portion 21 so that this second
nozzle 23c of the portion 28 traces in use the same circumference
C2 traced by a nozzle 23b of the portion 27; and a third nozzle 23b
arranged at a radial distance from the assembly portion 21 so that
it traces in use the same circumference C3 traced by a nozzle 23b
of the portion 27.
[0032] The position of the first nozzle 23b (in the sequence
counted from axis A) of the portion 28 is finally chosen so that
the radius R4 of the circumference C4 which it describes in use
about the axis A is greater than the radius R1 of the circumference
C1 traced in use by the first nozzle (again according to a sequence
counted from the axis A) of the portion 27 and smaller than the
radius R2 of the circumference C2 traced in use by both the second
nozzle 23b of the portion 27, and the second nozzle 23c of the
portion 28.
[0033] In this manner, the areas of the basket 4 progressively
further away from the axis A defined by circular crowns placed at
the circumferences C1-C4 and each having a radial width depending
on the opening angle of the jets 24 generated by the nozzles 23
tracing each circumference each time (therefore, areas of
progressively larger dimensions), are in use sprinkled by
progressively increasing flow rates of service fluid 8, called Q1,
Q2, Q3, Q4, the values of which will depend on the position
(circumferences C1-C4) and type (nozzles 23b and 23c) of the
nozzles 23 from which each circular crown is sprinkled in use.
[0034] According to the description and the illustration in FIG. 3,
the aforesaid overall flow rates will have the following
values:
Q1=q2;
Q2=q1;
Q3=q1+q2
Q4=q1+q1
[0035] It is thus apparent that by appropriately choosing the
position and sizes of the nozzles 23, each zone of the basket 4 may
be invested in use by a total amount of water L which remains
approximately constant, regardless of the distance from the
rotation axis A which is taken into account.
* * * * *