[0001] The present invention relates to a washing/drying machine, i.e. machines for household,
industrial or commercial use intended for washing and drying laundry in general.
[0002] These machines, therefore, have some elements in common with washing machines, e.g.
the washing tub or chamber that houses a rotary basket or drum; the clothing or laundry
to be treated is loaded into the basket through a door, which may be located at the
front or at the top, depending on the machine type.
[0003] The rotation of the basket keeps the load moving during the washing and/or drying
phases, when the tub is supplied with water and air, respectively.
[0004] In the course of the working cycle of the washing/drying machine, the load, consisting
of clothing, laundry and the like, normally releases filaments that are evacuated
through the drain.
[0005] This occurs in a simple and direct manner during the wash, in that water is supplied
and drained several times for washing the laundry with detergents, rinsing it, etc.,
so that the filaments released by the fabrics are removed from the laundry and evacuated
together with the water being drained.
[0006] When laundry is being dried, instead, the filamentous wads generated by the clothes
rubbing against the inner wall of the basket (the quantity of which increases as humidity
decreases) are dragged by the air flow that circulates in the machine and laps the
laundry items contained in the basket in order to dry them, but cannot be evacuated
in the same way because no water is supplied into the basket during the drying cycle.
[0007] As can be easily understood, the drying air must be cyclically filtered to prevent
the fan and the associated electric resistor from suffering damage.
[0008] To this end, it is known to take air from the washing/drying tub, filter it, reduce
the humidity thereof, and introduce it again into the tub.
[0009] The air is filtered as it flows through a filter comprising a grid or net made of
metal, plastic or the like, arranged on a wall of the washing/drying chamber (in particular,
on the back wall, at the outlet section towards the drying circuit), the mesh of which
is sufficiently tight to trap the filaments released by the fabrics; it can be easily
understood that the filamentous wads progressively depositing onto the filter will
reduce the air passage section thereof and will cause load losses that will slow down
the air flow, resulting in a general reduction of the efficiency of the laundry drying
cycle.
[0010] Document EP2439328A1 discloses a filtering unit for a drying machine. The filtering unit is provided with
an air inlet, an air outlet and a collector where foreign materials in the air accumulate.
The collector is rotatable around an axis and comprises at least two meshes disposed
at certain angles with respect to one another.
[0011] The present invention aims at overcoming this problem that affects the state of the
art.
[0012] Therefore, the technical problem at the basis of the invention is to provide a washing/drying
machine having such structural and operating characteristics that keep regular and
efficient air filtering conditions, so as to ensure the execution of a correct laundry
drying cycle.
[0013] The idea that solves this problem is to reduce or limit the quantity of filaments,
released by the laundry being dried by the air circulating in the washing/drying machine,
that will deposit onto the filter, thereby preventing excessive accumulation of filaments
thereon: in this way, it is possible to prevent the filter from getting clogged quickly,
thus keeping it efficient and reducing load losses for a longer time.
[0014] This effect is achieved, according to the teaching of the invention, by holding upstream
of the filter the filaments circulating together with the drying air flow.
[0015] The features of the invention as a whole are specifically set out in the claims appended
to this description.
[0016] Such features will become more apparent from the following description of a preferred
but non-limiting example of embodiment thereof as shown in the annexed drawings, wherein:
- Fig. 1 is a perspective view of a washing/drying machine according to the invention;
- Fig. 2 is a perspective view of the washing/drying tub or chamber of the machine of
Fig. 1, with the associated drying circuit;
- Fig. 3 is a perspective view of the washing/drying tub of the machine of Fig. 1 from
a different angle than Fig. 2;
- Fig. 4 shows the tub of Figures 2 and 3 with a part thereof removed to make the internal
parts visible;
- Fig. 5 shows the tub of Figures 2 and 3 with a part thereof removed to make the inner
wall visible;
- Fig. 6 shows some possible variants of the surface finish of the wall of the tub of
Fig. 5.
[0017] With reference to the above-listed drawings, reference numeral 1 designates as a
whole a washing/drying machine in accordance with the present invention, which comprises
an external structure 2 substantially shaped like a parallelepiped cabinet, with a
front panel 3 equipped with user controls (e.g. push-buttons, knobs, etc.) and various
indicators, lamps, displays, or other means such as detergent drawers, useful for
the control and operation of the machine 1.
[0018] It is worth pointing out that reference will be made in this description, for simplicity
and clarity, only to those elements of the washing/drying machine 1 which are useful
for understanding the invention; for more information, reference can be made to the
prior art, e.g. washing/drying machines created by the present Applicant or described
in patent applications filed by the latter on this matter, such as European patent
applications
EP 2116647,
EP 2281081,
EP1907616,
EP 1775368,
EP 1647621 and more.
[0019] At the front of the structure 2 there is the load opening 4 of the washing/drying
machine, which is closed by a door 5. The structure 2 of the washing/drying machine
internally houses a washing/drying chamber or tub 10, in which a basket 11 for loading
laundry to be treated is supported in a per se known manner. The chamber or tub 10
is intended for washing/drying laundry, in that a machine like the one considered
herein performs a dual function as a water tub during the washing cycle and as a drying
chamber during the drying cycle.
[0020] The basket 11 has the typical drum-like configuration, with a perforated wall allowing
water to flow through, as visible in Figures 1 and 4, and is equipped with inner paddles
or lifters 12 for stirring the load while rotating when the machine 1 is in operation.
[0021] The chamber 10 comprises a substantially cylindrical skirt or side wall 15 (possibly
slightly convex) closed at the rear by a back wall 16, while at the front it has a
collar 17 on which a gasket 18 is applied, sealing the opening 4 of the cabinet 12
of the washing/drying machine 1.
[0022] Outside the washing/drying chamber 10 a drying air circuit 20 is arranged, which
comprises an intake channel 21 (also acting as a condenser) and a delivery channel
22, between which a fan 23 is arranged for air circulation.
[0023] In particular, the delivery channel 22 extends from the collar 17 of the chamber
10 to the fan 23, whereas the intake channel 21 extends from the fan 23 to an intake
port formed in the back wall 16 of the chamber 10, where a filter 26 is arranged.
[0024] The latter is slightly eccentric relative to the axis of rotation of the basket 11,
where the support and/or rotation means of the basket 11, such as shaft, bearings,
pulleys, etc. (not shown in the drawings because per se known) are applied to the
back wall 16 of the chamber 10. The filter 26 may be designed in any suitable manner,
e.g. with a metal or plastic grid or net having a mesh suitable for trapping the filaments
released by the laundry being treated in the washing/drying machine 1; the mesh may
have a polygonal (e.g. square, rectangular, hexagonal) or circular shape, etc., the
mesh size being smaller than 1 mm
2.
[0025] In accordance with the invention, the inner walls of the washing/drying chamber 10
(in particular at least a portion of the side wall 15) have a rough, coarse or wrinkled
surface finish.
[0026] Such a finish can be obtained through any suitable machining, whether mechanical
or of a different nature (e.g. chemical, electric or electrochemical processes and
the like), with or without removal of material, whether carried out manually or by
using suitable machine tools. Some examples of suitable machining processes are knurling
(with or without chip removal), lapping, grinding, milling, pressing, abrasion, electroerosion,
and the like; their use will depend on the material used for the side wall 15 of the
tub 10, its thickness, the surface to be treated, and other factors related to industrial
production (e.g. costs, times, etc.).
[0027] Advantageously, the surface finish is obtained together with the rest of the tub
wall, being produced thereon during a single pressing operation.
[0028] Figure 6 shows some possible examples of surface finish of the wall 15, respectively
obtained by pressing, knurling and grinding; also the asperities 40 have different
profiles (corrugated, sawtooth, conical).
[0029] It must be pointed out that this finish may reproduce a regular or irregular pattern.
[0030] The wall 15 of the tub 10 is usually made of plastic material or, alternatively,
stainless steel, the thickness of which may vary from 1.8 to 2.5-3 mm; the surface
roughness of the side wall 15 has asperities 40 having a height of 10% to 40%, of
the thickness of the wall 15 of the washing/drying tub 11.
[0031] With the thickness values specified above, therefore, there will be asperities shorter
than 1 mm, according to the invention, in the range of 0.2 to 0.8 mm; in this regard,
it must be pointed out that also the back wall 16 (in particular the portion thereof
around the filter 26) and/or the collar 17 of the washing/drying chamber 10 may have
a rough surface finish, in accordance with the above explanation.
[0032] Though preferable, this is nevertheless not strictly necessary, and the surface finish
of the back wall 16 and of the collar 17 may be different from that of the cylindrical
side wall 15: this will depend on several factors, such as the shape and size of the
washing/drying chamber 10, the configuration of the air circulation circuit (i.e.
the intake 21 and delivery 22 channels, the fan 23, etc.), the characteristics of
the filter 26, etc. Irrespective of this, the operation of the washing/drying machine
1 described so far is as follows.
[0033] In order to dry the laundry, the fan 23 is activated and produces an air flow that
is taken from the chamber 10 through the channel 21 and is then reintroduced into
the same chamber 10 by means of the delivery channel 22; along its path outside the
chamber, the air is dehumidified in the condenser 21 and possibly heated by heating
means (e.g. an electric resistor arranged in the delivery channel 22), which are not
shown in the drawings because they are known in the art.
[0034] In the chamber 10, the air flow generated by the fan 23, in addition to removing
humidity from the load of laundry and various clothing, also removes many fibers and
filaments: however, unlike the prior art, these are held by the surface asperities
40 of the cylindrical side wall 15 of the chamber 10, and, if present, also by those
of the back wall 16 and of the collar 17.
[0035] As a result, when the air flow directed towards the external circuit 20 reaches the
filter 26, it will carry a reduced quantity of filaments, since they will have been
held upstream by the walls of the washing/drying chamber 10.
[0036] Thus, the filter 26 will only have to perform a fine removal of any residual filaments
in the air flow, so that there will be no risk of clogging due to bigger wads or downy
formations, as it happens in known washing/drying machines.
[0037] Therefore, this reduces the load losses caused by the filter, promotes air circulation,
and, consequently, increases the efficiency of the whole drying cycle.
[0038] The filaments held by the walls 15 (16 and 17) of the washing/drying chamber 10 are
then easily removed by supplying water into the chamber itself: this can preferably
be done at the beginning of a next washing cycle of the machine 1.
[0039] It can be easily understood from these explanations how this machine can solve the
technical problem addressed by the invention.
[0040] In fact, the capability of holding filaments through means other than the usual filters
arranged in the drying air circuit prevents, or anyway reduces, the risk of clogging
normally incurred by filters.
[0041] This result is attained thanks to the roughness characteristics given to the washing/drying
chamber 10, without needing any specific additional devices that would make the machine
1 more complex.
[0042] In addition to the embodiment taken into account herein, further variants of the
invention are of course also possible.
[0043] It has already been mentioned that also the back wall 16 and/or the collar 17 of
the chamber 10 may have a rough finish, in addition to the cylindrical side wall 15;
it must however be remarked that the principle of holding the filaments by exploiting
the surface finish of parts of the washing/drying machine can be extended to other
parts thereof.
[0044] For example, said principle may be applied to the outer wall of the basket 11, in
which case the outside of the basket will be given a rough finish as previously explained:
in this manner, the filaments will also be held by the basket, not just by the washing
chamber, leading to even better results.
[0045] Other variants can then be obtained by using air circuits 20 which are more complex
than the one of the case shown in the drawings.
[0046] All of these variants will still fall within the scope of the following claims.