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EP 1 199 515 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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02.07.2003 Bulletin 2003/27 |
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Date of filing: 08.10.2001 |
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International Patent Classification (IPC)7: F22B 1/28 |
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Steam generator with improved injector
Dampferzeuger mit verbesserter Düse
Générateur de vapeur avec buse améliorée
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Designated Contracting States: |
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AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR |
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Priority: |
16.10.2000 IT PN000063
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Date of publication of application: |
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24.04.2002 Bulletin 2002/17 |
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Proprietor: Euro Star S.r.l. |
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31058 Susegana, Treviso (IT) |
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Inventor: |
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- Di Leta, Cristiano
31020 San Vendemiano,
Treviso (IT)
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Representative: Giugni, Valter et al |
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PROPRIA S.r.l.,
Via Mazzini 13 33170 Pordenone 33170 Pordenone (IT) |
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References cited: :
EP-A- 0 638 684 US-A- 1 580 293
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EP-A- 1 026 306 US-A- 4 578 563
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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[0001] The present invention refers to a steam generator, which is suitable for use in a
number of different applications, such as for instance steam cleaning machines, clothes
irons, fan-assisted or suction-type ironing boards with refill function, coffee brewing
and similar machines, and namely such a steam generator provided with an improved
water injector.
[0002] EP-A-1 026 306 in the name of the same Applicant discloses a so-called vertical-axis
steam generator, into which the water is let via a conduit that extends through a
side wall of the steam generator in a horizontal direction. The water is let under
pressure into the interior of the steam generator in such a manner as to enable it
to practically hit against the opposite side wall, in a zone that corresponds to the
one in which the thermostat controlling the operation of the generator is actually
situated.
[0003] The steam generator described in the above cited European patent publication is certainly
advantageous, since it enables both the amount of water supplied to the generator
and the steam generation rate or rapidity to be varied. Furthermore, the particular
arrangement of the electric heating elements on the vertical side walls of the generator
enables the power output of the generator itself to be varied, up to a doubling thereof
in view of heavy-duty, industrial applications of the generator.
[0004] However, such a kind of steam generator may show some drawbacks when it is supplied
with water that is very rich in mineral salts, ie. with a high content of mineral
salts. In fact, limestone tends to form in these cases, particularly at the extremity
of the water injector and even in the interior thereof. Such a scaling effect tends
to accumulate, ie. build up, and, after a certain number of cycles of operation of
the steam generator, may even cause the water inlet in the generator to eventually
become clogged. The need therefore arises here for cleaning operations to be planned
and carried out periodically, and these cleaning operations are rather difficult and
certainly quite awkward to carry out, since they call for the generator to be first
emptied and then treated under utilization of special substances adapted to dissolve
the so formed limestone.
[0005] A steam generator according to the preamble of independent claim 1 is disclosed in
US-A-4 578 563.
[0006] It therefore is a main purpose of the present invention to do away or at least drastically
reduce the above mentioned drawback, so as to enable the steam generator to be used
throughout prolonged periods of time without any need arising for troublesome maintenance
operations to be carried out in view of removing the scale affecting the water injector
and, therefore, the steam generator itself.
[0007] This aim has been reached, as the result of successive experiments, in a steam generator
in which the water supply conduit extends into the interior of the generator with
an injector that reaches up to a point close to the wall carrying the heating element,
wherein the inner surface of this water injector is protected with the use of a lining
sheath of polymeric material, as this is recited in the appended claims.
[0008] Features and advantages of the present invention will anyway be more readily understood
from the description that is given below by way of non-limiting example with reference
to the accompanying drawing, in which:
- Figure 1 is a schematic view of a steam generator according to the present invention;
and
- Figure 2 is a partially sectional view of a detail of the steam generator illustrated
in Figure 1.
[0009] The steam generator according to the present invention illustrated in the Figures
is constituted by a hollow body 10 in the shape of a parallelepiped, which is arranged
with its major axis substantially vertical, and which has side faces having a larger
surface than the upper and bottom bases thereof.
[0010] The hollow body 10 is formed by two half-shells 11 and 12 which are joined to each
other along the peripheral edge 13 thereof. An electric heating element 14, duly provided
with terminals 15 for the connection thereof to the power supply line, is attached
to at least one of the side faces of the body 10. The water is let into the interior
of the hollow body via a conduit 16 which penetrates thereinto in a substantially
horizontal direction by passing through the wall on the opposite side of the wall
carrying the electric heating element 14.
[0011] On the electric heating element 14 there are mounted a thermostat 17, which controls
the energization, ie. operation of the water-supply pump (not shown), and possibly
a further safety thermostat 18.
[0012] The steam generated inside the generator 10 is delivered to the steam-using apparatus
(cleaning machine, steam iron or the like) via a conduit 19.
[0013] According to the present invention, the water supply conduit 16, which passes through
the wall of the half-shell 12, is made out of metal tubing, preferably a stainless-steel
pipe, and extends into the steam generator with an injector 21. The conduit 16, and
therefore also the injector 21, is normally welded on to the wall of the half-shell
12. The injector 21 is arranged in a substantially horizontal direction and the internal
extremity thereof terminates at a short distance from the wall of the opposite half-shell
11. In this manner, the sensitiveness and responsiveness of the thermostatic control
of the steam generator are enhanced, with the advantages that have already been described
in EP-A-1026306.
[0014] Again according to the present invention, in view of preventing limestone, ie. scale
from forming both in correspondence of the extremity of the injector 21 and in the
interior thereof, the inner surface of the injector is protected with the use of a
lining sheath 22 of a polymeric material. In particular, such a lining sheath 22 is
made of a thermosetting polymer.
[0015] Experimental tests have demonstrated that, among the most suitable materials for
this kind of application, the currently preferred one is a silicone ensuring a smooth
surface and a heat resistance of at least 250°C. This material furthermore features
excellent heat and electric insulation properties, along with a marked water-repellent
and non-stick capacity.
[0016] The lining sheath 22 may be applied using any practicable means known in the art,
although the solution that actually seems to be the technically most simple and advantageous
one is constituted by the insertion in the injector 22 of a lining sheath in the form
of a tubule 22.
[0017] In view of improving the anti-scaling effect at the extremity of the injector, the
tubule 22 is allowed to slightly protrude from the internal extremity of the same
injector. At its extremity facing the conduit 16, the tubule 22 has an annular collar
23 that enables it to abut against a corresponding inner prominence 24 of the injector
21. This makes it much easier for the tubule 22 to be inserted and properly arranged
inside the injector 21, while preventing the same tubule from possibly slipping out
owing to the action of the supply pressure of the water.
[0018] The above described innovatory solution has been illustrated in connection with a
steam generator of a vertical-axis type, into which the water is let via a conduit
that penetrates thereinto in a horizontal direction through a side wall of the generator.
However, anyone skilled in the art will readily appreciate that this solution may
be advantageously applied to steam generators of any type, even horizontal-axis or
inclined-axis ones.
1. Steam generator comprising a hollow body (10) into which the water is let via a conduit
(16) that penetrates thereinto by passing through the wall opposed to the one that
carries a heating element (14), the conduit (16) extending into the interior of said
hollow body (10) with an injector (21) that reaches up to a point close to the wall
carrying said heating element (14), characterized in that the inner surface of said injector (21) is protected by a lining sheath (22) of a
polymeric material.
2. Steam generator according to claim 1, characterized in that said lining sheath (22) is made of a thermosetting polymer.
3. Steam generator according to claim 2, characterized in that said lining sheath (22) is made of silicone.
4. Steam generator according to any of the preceding claims, characterized in that said lining sheath (22) is constituted by a tubule inserted into said injector (21).
5. Steam generator according to claim 4, characterized in that the tubule (22) is allowed to slightly protrude from the internal extremity of the
injector (21) and is provided with an annular collar (23) at its extremity facing
the water-supply conduit (16) so as to be able to abut against a corresponding prominence
(24) provided inside the injector (21).
1. Dampferzeuger, der einen hohlen Körper (10) umfasst, in den das Wasser über eine Leitung
(16) eingelassen wird, die in ihn eindringt, indem sie durch die Wand hindurchtritt,
die der gegenüberliegt, die ein Heizelement (14) trägt, wobei sich die Leitung (16)
in das Innere des hohlen Körpers (10) mit einer Einspritzdüse (21) hineinerstreckt,
die bis zu einem Punkt nahe an der Wand reicht, die das Heizelement (14) trägt, dadurch gekennzeichnet, dass die Innenfläche der Einspritzdüse (21) von einer Auskleidungshülse (22) aus einem
Polymermaterial geschützt wird.
2. Dampferzeuger nach Anspruch 1, dadurch gekennzeichnet, dass die Auskleidungshülse (22) aus einem wärmehärtbaren Polymer besteht.
3. Dampferzeuger nach Anspruch 2, dadurch gekennzeichnet, dass die Auskleidungshülse (22) aus Silikon besteht.
4. Dampferzeuger nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass die Auskleidungshülse (22) durch ein Röhrchen gebildet wird, das in die Einspritzdüse
(21) eingeführt ist.
5. Dampferzeuger nach Anspruch 4, dadurch gekennzeichnet, dass das Röhrchen (22) geringfügig aus dem inneren Ende der Einspritzdüse (21) vorstehen
kann und mit einem ringförmigen Bund (23) an seinem äußeren Ende versehen ist, das
der Wasserzuführleitung (16) zugewandt ist, so dass es an einem entsprechenden Vorsprung
(24) anstoßen kann, der im Inneren der Einspritzdüse (21) vorhanden ist.
1. Générateur de vapeur comprenant un corps creux (10), dans lequel l'eau est introduite
via un conduit (16) y pénétrant, par passage à travers la paroi opposée à celle portant
un élément chauffant (14), le conduit (16) s'étendant à l'intérieur dudit corps creux
(10), avec un injecteur (21) atteignant un point proche de la paroi portant ledit
élément chauffant (14), caractérisé en ce que la surface intérieure dudit injecteur (21) est protégée par une gaine de revêtement
(22) en matériau polymère.
2. Générateur de vapeur selon la revendication 1, caractérisé en ce que ladite gaine de revêtement (22) est réalisée en un polymère thermodurcissable.
3. Générateur de vapeur selon la revendication 2, caractérisé en ce que ladite gaine de revêtement (22) est réalisée en silicone.
4. Générateur de vapeur selon l'une quelconque des revendications précédentes, caractérisé en ce que ladite gaine de revêtement (22) est formée d'un tubule, inséré dans ledit injecteur
(21).
5. Générateur de vapeur selon la revendication 4, caractérisé en ce que le tubule (22) est installé légèrement en saillie depuis l'extrémité intérieure de
l'injecteur (21) et est muni d'une collerette annulaire (23) à son extrémité placée
face au conduit d'alimentation en eau (16), pour être en mesure de venir buter contre
une proéminence (24) correspondante, prévue à l'intérieur de l'injecteur (21).