Note: Descriptions are shown in the official language in which they were submitted.
~ - - 21 93336
,
1 DISHWASH~R WITH IMPROYED DEV~CE FOR DRYING BY CONDENSATION
2 BAc~GRou~D oF THE INVENTION
3 ~he invention concerns a di~hwa~her, in particular a
4 hou~ehold dishwasher, provided with an lmproved devlce for
the conden~ation of moi~ture from the air contained in a
6 wa~hlng basin.
7 It i~ ~nown that in di~hwa~he~6, in particular
8 hou~ehold dishwa~hers, a method of drying the dishe~ by
9 means of dehumidification of the air saturated with water
~apor contained in the washing basin is CG on- This
11 dehumidification is accomplished by making the moist air
12 pa~ through a ~uitable conduit provided with a blower or
13 ~entilator that provides for circulation of the air. A
14 heat exchanger with a cold body is applied to the conduit
to condense the moisture.
16 Usually, the condensed water is returned to the basin
17 by ~ravit~, following the air ~low. The cold body is
18 usually a heat-conducting su~face that is cooled in turn by
19 an air flow taken from and returned to the air outside of
the dishwa~her a~ter having passed over the heat-conducting
21 ~urface. This type o~ dishwa~her~ i~ di~closed, ~or
22 example, in patent GB 2263969, which has the doublc
23 inconvenience o~ a heat exchanger made of a single ~urface,
24 over which counte~-currents pass on two oppo~ite faces and
~herefore with low efficiency, and the fact that the motor
26 tbat activates the fan i8 placod in ~he ~pper back corner
27 of the dishwasher cabinet, thu~ occupying a ~pace that
28 reduces the usable volume of the basin.
29 Patent GB 2265820 is functionally similar to the one
mentioned above; the sole difference is the different
31 position of the aspiration and expulsion openings for the
32 out~ide cooling air, wh~ch in thi6 patent are placed on
33 backwall.
~ 21 93336
1 Patent GB 2262027 (TOSHIBA) disclose~ mean~ for drying
Z ~y condensatio~ in a di~hwasher having a vertical wall
3 along which a circulation of moist hot air coming ~rom the
4 wa~hi~g ba~in, with a ~heet of cold water ta~en from the
S outside water-distribution network passing over said
6 vertical wall. The temperature dif~erence between the
7 surfaces of said vertical wall and the flow of moist hot
8 air that is blown so as to contact said wall aa~se
9 condensation of the ~oisture in the air.
ln This solution is certainly adequate and even very
11 effic$ent for energetic drying of the air; however, it has
12 the great inconvenience o~ requiring a significan~
13 additional consumption of water ~rom the water network as a
14 mean~ of cooling, and this fact is in direct opposition to
the requirement and efforts of manufacturers of dishwashers
16 to offer products on the market that need ever le~s wate~,
17 energy, and detergent~ and accessories in order to ~unction
18 correctly and ~till provide sati6fa~to~y ~ervices.
19 The solution disclo~ed in patent DE 39 38 170 tSanyo
Electric Co.) ~ses a single dual-purpose fan, which
21 certainly reduces the complexity and the cost o~ the
22 device; however, as with the patent~ already mentioned, it
23 repeats their inconvenience6 ~ including the ~act that the
24 flows of moist hot air ~rom the cooling and o~ cooling air
are in parallel currents and that the ~an and the motor ar~
26 arranged behind the basin, reducing the u~able volume
27 the~e.
28 Moreover, the use of the dual-purpose fan, with the
29 necessity o~ limited interspaces for play be~ween the
blade~ of the fan and the two di~tinct air-flow channels,
31 makes ~t inevitable that moist air is drawn to the outsid~
32 o~ the mac~ine, which is something that i8 desirable to
33 avoid.
34 Patent DE GM oo z6 939.2 disclo~e~ a type of household
dish~asher provided with a condensation ~ystem ~or moist
36 air that only make~ the air circulate in a conduit external
37 ~o the ba~in in which the condensation occurs by a heat
21 93336
1 eYch~e wit~ the adjacent side walls of the cabin~t.
2 In thi~ case too, the inconvenience~ of weak cooling
3 action and therefore of cond~nsation a~e ob6erved, whic~
4 ~hould in fact be reinforced by activation o~ a cooling of
the air in thi~ conduit. In practice there i8 a c_ n
6 electrical re~istance, which increaseG the temperature
7 di~ference in the air between the two end6 of ~aid conduit.
8 However, thi~ contrivance worsen~ energy conYumption and
9 ~ake~ the machine more complicated, more costly, and also
more delicate in u6e.
11 BRIE~ SUMMARY OF THE INVENTION
12 It would there~ore be desirable, and is the goal o~
13 the present inven~ion, to make di6hwashers provided with
14 mean~ for drying by condensation of the moi~t air t~at are
~unctionally e~ficien~, ~imple, and require only min~mal
16 consumption of supplementary energy.
17 BRIEF DEscRIPTION OF TI~E SE~ERAL VIEWS OF THE DRAWING
18 The invention will be understood better by mean~ o~
19 the following de~cription, whlc~ is given only by way of a
non-limiting example, and with reference to the attached
21 diagrams, in which:
22 Fig. 1 ~hows schematically a main diagram, viewed from
23 the side, of a dishwasher having a condensation device
24 according to the invention;
F~gs. 2 and 3 ahow separately two sub-as~emblie~ o~
26 the invention, which a~e assem~led in sequence;
27 Fig. 4 ~hows a perspective view, partially cut away,
z8 of the device acaording to the invention; and
29 Figures 5 and 6, respectively, show a horizontal and
30 vertical section of the device of Fig. 4 taken from lines
31 5-5 and 6-6, respectively.
21 9333~
DESCRIPTION OF ~HE ~:~V~;N l ~ON
2 In the following description, the torm "air" will be
3 used as equivalent to the term "moist hot air," but the use
4 of one ter~ or the other does not affect the clarity of the
presentation, given the context in which these term6 are
6 used, as will be evident to an expert in the field.
7 As shown in Fig. l, The invention includes a flr~t
8 vertical conduit 1 and a second conduit 2, essentially
g perpendicular to the flr6t conduit. The fir~t conduit 1 is
connected to the interior of the ~a~in by means of upper
11 and lower opening~ 3 and 4, respectively, located at
12 corresponding end part6 of the fir~t conduit.
13 A first motorized fan 5 i8 suitable for a~piratlng
14 air in th~ough the upper opening 3 and is located near the
lower opening 4. The second conduit 2 is open at its end~,
16 wit~ a co~responding a~piration ~ntake 55 and di6charge
17 outlet 6, both of which open to thQ out~ide. A second
18 motorized fan 7, ~uitable for making air taken ~rom the
19 out~ide circulate through said second conduit i6 located
near the a~plration intake 55.
21 Referring also to Figs. 2 through 6, the first and
22 second conduits intersect in a heat exchanger 8, made
23 8ub~tantially so as to have ~e~eral first parallel channel~
24 9 inserted in the fi~t conduit in such a way that the
entire air flow of said fir6t conduit ifi completely divided
~6 among said fir~t channels. The first channel~ are
27 ~eparated from each other by interspaces lo, in which
28 second parallel channels 11 are fitted. The second
29 channels 11 are inserted into said second conduit in such a
way that the internal air flow of sald s~cond co~duit i~
31 divided among three second channels. The heat exchanger i6
32 configured so that the fir~t channels Y and the second
33 channels 11 are arranged in perpendicular direction~.
34 Conden~ate produced ~y the moist ai~ that flows
through 6aid first channels descends or falls through a
36 final ~egment 20 of ~aid fir~t conduit downstream from ~aid
~ 21 q3336
1 heat exc~anger by gravity into the basin through the lower
2 opening 4, which i~ placed in a po6ition underneath the
3 position of said exchanger.
4 The advantage of this config~ration cau~ing division
of the air flow~ i~ that the area of the heat exchange i~
6 increased enormou~ly without ~ignificantly ~ncreasing the
7 volume or the dimen~ions o~ the heat exchanger. ~hi~
8 configuration, together with the fact that the flow~ are
g perpendlcular, signiflcantly improvQ~ the efficiency of the
heat exchanger, a6 demonstrated in numerous laboratory
11 test~. A simpli~ied version of this type of ~rh~Anger
12 uses a single pair of chann~l~, one for the cooling a~r and
13 one for the moist air to be dried, but this solution
14 provide~ less efficiency in the heat excha~ge.
Even though these channels can have cross-sections o~
16 various ~hape~ and need not be pa~ticularly elongated, a
17 preferred configuration i9 illustrated in the diagrams, in
18 particular in Figures 2 and 3. A~ ~hown, the first
ls parallel channels g have a highly elongated rectangular
cross-section and with ~imilar dimensions, arranged side by
21 side, but ~eparated from each other by corresponding
22 inter~pace~ lo, similar to the second parallel channel~ ll,
23 which a~e placed between the interepace~ that ~eparate the
24 first parallel channel~. Thi~ kind of con~iguration
inC~ease~ the areas that are side by side each other and
a 6 thereby increa~es the heat exchange.
27 The invention includes several possible alternatives.
28 ~ir~t, the ~especti~e wall8 13 and 14 of said first and
z9 second parallel channels, illustrated separately in Figure~
2 and 3 ~or simplicity, can be ~oined in the construction
31 phase in such a way that a pair of adjacent walls i9 made
32 as a ~ingle physical wall, suitable for defining ~oth
33 channels located on opposite faces of each wall, a~ ~hown
34 in Fig. 4. This permits the production of the exchanger to
be simplified and economized and also lmproves the heat
36 eY~hA~ge between ad~acent channels i~ improved.
37 A further alternative, useful because i~ occupie6 th~
_ 21 ~3336
1 18a8t po6sible 6pace, i~ given-by thQ fact that the fan~
2 are motorized by a single motor, to which sUitable coupling
3 device6 are connected. The motor ~its dlrectly onto a
4 shaft of the eecond ~an 7, which i6 placed under the basin.
The motor tran~mits motion to the flr~t fan 5 by mean6 of a
6 suitable belt 16 placed between two ~uitable pulleys
7 mounted on the re~pective fans.
8 The motor i8 also positioned in such a way as not to
9 be exposed to the cold air aspirated from the outside,
because otherwise the heat relea~ed during it~ operation
11 would heat thi~ cooling air, significantly reducing its
12 capaclty to aondense hot moi6t ai~.
~3 In order to favor passage of the cooling alr into sald
14 ~econd conduit, the intake 55 and outlet 6 are a~ra~ged in
two opposite d~rections, pre~erably one on the front 17 and
16 the other on the back 18.
11 Although the invention as been de6cribed with the
18 example of the preferred embodiment and with a known
19 terminology, thi~ i8 ~ot considered limiting, because an
expert in the field can apply numerou~ variations to it.
