U.S. patent application number 12/279503 was filed with the patent office on 2009-03-19 for domestic clothes drier with twin fan.
This patent application is currently assigned to ELECTROLUX HOME PRODUCTS CORPORATION N.V.. Invention is credited to Ugo Favret, Flavio Noviello.
Application Number | 20090071029 12/279503 |
Document ID | / |
Family ID | 38066433 |
Filed Date | 2009-03-19 |
United States Patent
Application |
20090071029 |
Kind Code |
A1 |
Favret; Ugo ; et
al. |
March 19, 2009 |
DOMESTIC CLOTHES DRIER WITH TWIN FAN
Abstract
Dryer with a drum (1) where the clothes must be placed, one fan
(5) blowing a drying air current through such drum, a condenser (3)
in which such drying air current enters, a cooling air duct (4)
blowing a second fresh air current through the condenser, produced
by a second fan (6) connected to the air duct; at least one of
these fans is composed of one set of external blades (10, 11, 12)
and a second set of internal blades (21, 22, 23) that spin on a
common axle (X), and the blades of the first set are laid out along
one cylindrical structure, while the second set of blades are laid
out along a second cylindrical structure inside the first one.
Inventors: |
Favret; Ugo; (Casarsa,
IT) ; Noviello; Flavio; (Aviano, IT) |
Correspondence
Address: |
PEARNE & GORDON LLP
1801 EAST 9TH STREET, SUITE 1200
CLEVELAND
OH
44114-3108
US
|
Assignee: |
ELECTROLUX HOME PRODUCTS
CORPORATION N.V.
Zaventem
BE
|
Family ID: |
38066433 |
Appl. No.: |
12/279503 |
Filed: |
January 29, 2007 |
PCT Filed: |
January 29, 2007 |
PCT NO: |
PCT/EP07/00723 |
371 Date: |
August 14, 2008 |
Current U.S.
Class: |
34/130 |
Current CPC
Class: |
F04D 29/283 20130101;
D06F 58/24 20130101; F04D 17/165 20130101; D06F 58/02 20130101 |
Class at
Publication: |
34/130 |
International
Class: |
D06F 58/04 20060101
D06F058/04 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 15, 2006 |
IT |
PN2006U000004 |
Claims
1. Clothes drying machine or combined clothes washing and drying
machine comprising a drum (1) containing the clothes to be dried,
at least one first fan (5) able to blow a first flow of drying air
through said drum, optionally a condenser (3) inside which said
drying air flow is made to pass and an associated cooling air duct
(4) which conveys a second flow of fresh air through said condenser
(3), said second flow being actuated by a second fan (6) associated
with said air duct (4), characterized in that at least one of said
fans (5, 6) is formed by means of a first set of outer vanes (10,
11, 12) and a second set of inner vanes (21, 22, 23) rotating with
respect to a common axis (X), in that the vanes of the first set of
vanes are distributed on a first cylindrical form, and in that the
vanes of the second set of vanes are arranged along a second
cylindrical form which is different from the first cylindrical form
and are arranged inside said first cylindrical form.
2. Machine according to claim 1, characterized in that a base of
the cylinder which is defined by the first set of vanes is at least
partly closed by a wall (P).
3. Machine according to claim 2, characterized in that the vanes of
the second set of vanes arranged internally are fixed at one of
their ends to said wall (P).
4. Machine according to any one of the preceding claims,
characterized in that said vanes of said first set are radial with
respect to said common axis (X).
5. Machine according to claim 4, characterized in that said vanes
of the second set of inner vanes (20, 21, 22) are oriented in a
non-radial direction with respect to said common axis and have a
given inclination (i) with respect to the respective radial planes
passing through them.
6. Machine according to claim 5, characterized in that said given
inclination is such that the outer edges (45, 46, 47) of respective
inner vanes are situated further forwards than the respective inner
edges (45A, 46A, 47A).
7. Machine according to any one of the preceding claims,
characterized in that said inner vanes have a concave surface (C1,
C2, C3) directed in the sense of rotation of said fan.
Description
[0001] The present invention relates to an improved type of clothes
drying machine, preferably of the domestic kind, which operates in
a particularly efficient manner.
[0002] In the continuation of the present description reference
will be made to a simple clothes dryinq machine, but it is
understood that the above explanation may also be applied in an
identical manner to--and therefore is also valid for--a combined
washing and drying machine.
[0003] Clothes drying machines which operate using different
methods are known, in particular those operating by means of
condensation of a flow of hot air which is blown into the drum and
which removes the moisture contained in the clothes or by
discharging externally said flow of moist hot air.
[0004] Said clothes drying machines are described generally in the
European Patent Application No. EP 04 009650.5, in the name of the
same applicant, to which, for the sake of brevity, reference should
be made.
[0005] However, in order to assist the reader, a short descriptive
part of said document is included here.
[0006] As is well-known, these machines are made by installing a
heating and ventilation system, normally a ventilator consisting of
a fan and associated electric motor, which draws the air from the
outside and by means of suitable ducts heats it and blows it into
the drum containing the clothes to be dried.
[0007] A heating element is installed inside said duct and,
suitably activated, heats the air which passes over it and is blown
in by said ventilator, so that hot air is introduced into the drum
so as to cause evaporation of the moisture contained in the
clothes.
[0008] After being introduced into the drum, the hot air causes
evaporation of the moisture contained in the clothes and therefore
is practically saturated or completely saturated with it; said air
is then propelled by said ventilator, creating a continuous flow
which is directed into a suitable condensation device, usually
consisting of a heat exchanger which is passed through, along the
so-called "hot" path, by said moist hot air flow and, along the
so-called "cold" path, by a substantially continuous flow of air
drawn from the environment and introduced back into the environment
after passing through said exchanger.
[0009] Conventionally, said air flow along the "cold" path is also
activated and maintained by a ventilator operated by a respective
electric motor.
[0010] Said clothes drying machines are fairly simple, low-cost and
operationally reliable machines, but, as is well-known, they have
the common drawback that they are significantly noisy owing to the
air flow which is blown in at a considerable rate inside the
suction and discharge ducts.
[0011] Consequently, the use of these machines is normally limited
to certain periods, this making their use less attractive for the
average user.
[0012] The most immediate technical solution for achieving the
circulation of said two separate air flows is that of using
respective ventilators inserted inside the corresponding ducts and
operated by respective motors which are controlled
independently.
[0013] Obviously said two ventilators use a not insignificant
amount of power, owing to, not only mechanical friction factors
which, however, are of limited importance, but also and in
particular the power which must be used in order to impart to the
respective air flows the desired speed, or pressure, at the
necessary flowrate.
[0014] It would therefore be desirable, and this is the main object
of the present invention, to provide a clothes drying machine of
the condensation or externally discharging type, which is provided
with fans for drying and if necessary cooling the condenser and is
able to offer a normal drying performance, but which is
significantly more efficient, without increasing the complexity of
the machine, while keeping the production costs low.
[0015] These and other objects which will be described further
below are achieved by providing a clothes drying machine according
to the claims which follow; the invention will be understood more
clearly from the following description, provided solely by way of a
non-limiting example with reference to the accompanying drawings,
in which:
[0016] FIG. 1 shows a general schematic diagram of a clothes drying
machine provided with a condenser and two fans which are rigidly
connected together, according to the prior art;
[0017] FIGS. 2 and 3 show two perspective views, i.e. a front view
and side view, respectively, of a fan for circulating air in a
machine according to the invention;
[0018] FIG. 4 shows a front view of the said fan;
[0019] FIG. 5 shows a cross-sectional view through the centre of
the said fan;
[0020] FIG. 6 shows a front view of a variant of embodiment of the
fan according to the invention;
[0021] FIG. 7 shows, in a same diagram, two: separate graphs
illustrating the progression of the pressure and electric power
consumption of the motor in a clothes drying machine with a fan
according to the prior art (graph A) and with a fan which is the
same, but equipped with the present invention (graph B),
respectively.
[0022] With reference to FIG. 1, in a clothes drying machine
according to a preferred embodiment of the invention, a drum 1 is
provided for containing the clothes to be dried and has, associated
with it, a duct 2 for circulation of the drying air; the latter
also passes through a condenser 3 which is able to condense the
moisture present in the air passing through it, said condenser
being passed through by a "cold" air flow, namely one which is
drawn from the environment and conveyed to the said condenser 3 via
an associated duct 4.
[0023] Both the ducts 2 and 4 contain inside them two respective
fans 5, 6 for actuating the respective drying and cooling air
flows.
[0024] One of said fans, or both of them, consist of two sets of
vanes which are arranged on the outer surface of a respective
cylindrical form, said two cylindrical forms being understood in
the non-material sense.
[0025] Said cylindrical forms are moreover coaxial and the radius
of a first cylindrical form is smaller than the radius of the
second cylindrical form.
[0026] Essentially the two cylindrical forms, and therefore also
the two sets of vanes, are inserted inside one another, without
touching however, as is clearly illustrated in FIGS. 2 to 5.
[0027] The vanes 10, 11, 12 . . . of the first set, or outer set,
are rigidly supported by a wall "P" arranged along a geometric base
of the respective cylindrical form, and the supporting structure of
said fan is thus formed.
[0028] Advantageously the vanes of the set of inner vanes 20, 21,
22 . . . of the second set are likewise supported on said wall "P"
such that the vanes of both sets are joined together and can rotate
in synchronism.
[0029] Still with reference to FIGS. 2, 3 and 4, in order to avoid
damaging vortices on the inner vanes, advantageously the latter
have a shape which is not flat but curved, i.e. with the associated
concavities C1, C2, C3, etc., directed in the sense of
rotation.
[0030] Moreover and preferably the free ends of the vanes of each
set are connected by a respective reinforcing ring 7, 8.
[0031] The fan according to the invention is thus formed.
[0032] The mode of operation of this fan will now be clear: in fact
the air which is sucked in by the cavity between the two sets of
vanes is forced outside by the outer vanes in accordance with known
mechanical principles, while the air sucked inside the inner vanes
is naturally blown outwards, i.e. into said cavity, with a certain
given speed which is added to the speed imparted by the outer vanes
through which it passes immediately afterwards.
[0033] Basically operation similar to that of a twin-stage fan
occurs, in which at least part of the air sucked in is subject to
the series action of the vanes of the two sets.
[0034] Obviously the flow of said air blown from the inner vanes
also assists the movement of the air sucked directly from the
outside into said cavity, this favouring the general efficiency of
the fan.
[0035] It may also be considered that the air blown out from the
set of inner vanes is slightly slowed down by the air sucked in
directly from the outside into said cavity; however, the overall
effect is an improvement in the efficiency of the fan, as
demonstrated by FIG. 7, which shows two graphs illustrating the
flowrate of a fan with and without the invention, the graph A
showing the pressure and the consumption of a fan without the
invention and the graph B showing the corresponding parameters of
the same fan to which the set of inner vanes according to the
invention has been added.
[0036] With reference to FIG. 4, it has also been observed that in
certain embodiments and in certain operating conditions, for
example when the fan must operate always in the same direction of
rotation, or, as more frequently occurs in a clothes drying
machine, in a main direction of rotation, the efficiency of the fan
is further increased if the inner vanes are provided with an
orientation which is not radial, but inclined at a given angle "i"
with respect to the radial plane which passes through the latter,
and in particular if said inner vanes are inclined such that,
taking as a reference the direction of rotation "S" of the fan, the
outer edges 45, 46, 47 of each inner vane are situated further
forwards than the respective inner edges 45A, 46A, 47A, obviously
relative to the planes p1, p2, p3 which pass through said
respective vanes.
[0037] However, more generally it is possible to envisage fans
which are operated in an alternating manner and for identical
periods in each direction of rotation; in this case it is obviously
advantageous if the vanes of the fan also do not have preferential
forms, but on the contrary, as shown by way of example in FIG. 6,
all the inner vanes are flat and arranged radially.
* * * * *