[0001] The present invention relates to an improved kind of centrifugal turbine pump, preferably
of the type generally used in connection with electrical home appliances, such as
clothes washing machines, dishwashers, and the like, and provided therefore with such
design and operating specifications as generally required in view of such applications.
[0002] Since pumps of the above-cited kind are generally used in appliances and machines
that are required to be very competitive as far as both costs and energy efficiency
are concerned, a considerable, constant effort is most obviously being made in industry
by manufacturing and design engineers in an attempt to continuously improve the overall
operating and construction characteristics of such pumps.
[0003] Centrifugal turbine pumps of the type covered by the present invention are generally
mass-produced on a vast industrial scale so that, owing to reasons pertaining to substantially
manufacturing costs and space requirements, i.e. compact size, there is no possibility
for all typical measures and provisions of both a design and technical nature to be
taken and implemented in these pumps as they are on the contrary usually taken and
implemented in pumps for industrial and professional applications in general, in which
there are involved much higher flow rates and power ratings, actually.
[0004] Therefore, the efforts of manufacturing and design engineers are in this case particularly
focussing on the possibility of providing impellers and pumping chambers that are
effective in bringing in sensible improvements in the overall efficiency, so as to
achieve a natural reduction in the size and the power rating of the motor used to
drive said impeller.
[0005] What is obtained in this way, actually, is therefore a twofold advantage in terms
of an improved water-handling, i.e. hydraulic efficiency and a resulting reduction
in the size - and therefore the costs - of the motor used to drive the pump.
[0006] Anyway, a reduction in the size of the pumping chamber and, in general, also in the
cross-section are of the delivery or discharge conduit connected thereto, gives rise
to a drawback that is particularly felt as such in the home appliance industry where
these pumps are used; in fact, with reference to Figure 1, which is a copy of Figure
10 appended to the patent publication
WO 2005/108976, and to Figure 2, which depicts a known turbine pump , these can be noticed to be
planar sectional views - orthogonally to the axis of the impeller - of a pumping chamber
according to the prior art. It can be noticed that the diameter D of the delivery
conduit 2 does neither narrow nor widen at the outlet from the pumping chamber 3,
since said delivery conduit 2 is directly connected to the machine-side use conduit
40, which - as just roughly schematized in the above-cited Figures - is connected to
said delivery conduit 2 of the pump immediately downstream therefrom, and has the
same diameter D as said delivery conduit 2, actually.
[0007] The above-cited drawback derives from the fact that, if the size of the pumping chamber
3 is reduced, then the diameter of the delivery or discharge conduit of the pump has
of course to be reduced, as well. However, since the diameter of the utilization conduit
40 will remain unvaried due to imperative constraints set by such conduit having to
mechanically interface with the appliance parts using the liquid delivered by it,
it quite obviously ensues that the pumping chamber 3 has to join up into the delivery
conduit 2 in the way as this is schematically illustrated in Figure 3, in which there
can be noticed that the diameter D1 of the delivery conduit shall join up into the
diameter D2 of the contiguous utilization conduit
40 attached thereto in a very quick manner.
[0008] Such situation causes a chamber 22 to come practically into existence where said
two conduits join into each other, the shape and position of this chamber being such
as to give rise to a vortex, i.e. whirling flow conditions.
[0009] As is largely known in the art, vortices are the cause of losses in hydraulic efficiency
that, in pumps of a general type as the ones covered by the present invention, may
be quite sensible.
[0010] In view of reducing this problem, an option may of course lie in providing an appropriately
shaped and contoured joint configuration with a gradually increasing cross-section
area, so as to avoid forming chambers in which vortices can develop and become established.
[0011] Generally, however, such kind of joint just cannot be implemented with the appliance-side
utilization conduits, whose design specifications are already defined and set in view
of the afore-cited mechanical-interface constraints.
[0012] US 2,999,617 discloses the features of the pre-characterizing portion of appended Claim 1, i.e.
a centrifugal turbine pump comprising an intake conduit, a delivery conduit, a pumping
chamber, an impeller housed in the pumping chamber, and a plurality of vanes arranged
on and attached to the impeller. The delivery conduit comprises a transition region
extending from an inflow section to a discharge or outflow section thereof, and the
round cross-section area of the delivery conduit increases along the transition region
in a gradual, continuous manner.
[0013] US 4,629,394 also discloses a centrifugal pump having a flow diffuser the round cross-section
area of which increases gradually.
[0014] US 5,127,800 refers to a centrifugal pump with a two-piece discharge nozzle with round cross-section
expanding outwardly with a gradually increasing cross-section.
[0015] Document
JP 59 131799 presents a centrifugal hydraulic machine wherein a diffuser is provided expanding
with a precise diffusing angle.
[0016] US 2,635,548 discloses a rotary pump having a case from which a round outlet neck extends for
letting the fluid out. The cross-section of the neck gets wider as long as it moves
away from the case.
[0017] DE 40 27 914 A1 shows a rotary pump having an outlet, the shape of which opens gradually outwardly,
divided by a separating wall.
[0018] It would therefore be desirable, and it is the main object of the present invention,
actually, to provide a kind of centrifugal water turbine pump that is effective in
doing away with the two above-indicated drawbacks of prior-art pumps of the same kind,
so as to ensure a high water-handling, i.e. hydraulic efficiency, jointly with a pumping
chamber that, apart from having a reduced size, is adapted to eliminate the afore-cited
mechanical-interface constraints set by the pump having to be coupled mechanically
to the appliance parts using the liquid delivered by the pump, and is further adapted
to prevent vortices, or whirling flow conditions, from being generated downstream
from the pumping chamber.
[0019] According to the present invention, these aims are reached in a centrifugal turbine
pump incorporating the features as defined and recited in the appended claims.
[0020] 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 drawings, in which, further to Figures 1, 2 and 3 already mentioned
and described hereinbefore:
- Figure 4 is an outer perspective view of a turbine pump according to the present invention;
- Figure 5 shows a projection, along to the plane lying orthogonally to the axis of
the impeller, of the same impeller, the pumping chamber and the delivery conduit,
according to a first embodiment of the present invention;
- Figures 6A to 6E are respective cross-sectional views of the delivery conduit, as
taken orthogonally thereto and arranged at regular intervals from each other;
- Figure 7 is a further outer perspective view of the pump according to the present
invention, as viewed from a point situated on the axis of the delivery conduit thereof.
With reference to Figures 4 and 5, a centrifugal turbine pump according to the present
invention comprises an intake conduit 1, a delivery or discharge conduit 2, a pumping
chamber 3, an impeller 4 housed in said pumping chamber in a manner that is largely
known as such in the art, and a plurality of vanes 5 applied to said impeller along
the circumference thereof.
[0021] Between the inflow section S1 and the outflow section S2 of the delivery conduit
2 there is formed a transition region 6 that is physically part of said delivery conduit.
[0022] According to the present invention, the area of said inflow section S1 is made significantly
smaller than the area of said outflow section S2.
[0023] With particular reference to Figure 5, said delivery conduit is provided so that
it widens gradually out in its cross-section to develop into such shape that a projection
thereof on a plane lying orthogonally to the axis
X of the impeller would trace out a P-shaped contour
P featuring two concavities C1, C2, the first one C1 of which faces the exterior of
the conduit with a vertex V1, whereas the second one C2, with a vertex V2, is facing
the interior of the same conduit.
[0024] These two mutually opposing concavities are therefore divided from each other by
a point of inflection
F.
[0025] In a preferred embodiment of the delivery conduit, the face 7 of the inner surface
portion of said P-shaped contour that faces the pumping chamber 3 is given a substantially
planar shape, so that the projection thereof on a plane lying orthogonally to the
axis C of said delivery conduit 2 appears as a segment 7.
[0026] In fact, if properly and accurately designed, such feature will generally enable
the length of the delivery conduit to be reduced, however without introducing any
risk of small vortices being likely to be brought about by the shortness of the delivery
conduit
[0027] It can therefore be most readily appreciated that any possibility is substantially
prevented for vortices to be created in the so-called "dead" zone, i.e. in the zone
along which the delivery conduit extends alongside the outer side of the pumping chamber.
[0028] Therefore, the actual advantage of the present invention lies in providing a centrifugal
turbine pump, the delivery or discharge conduit of which features such inflow section
as to be able to make as best as possible a use of and take as best as possible an
advantage from the characteristics of the pumping chamber, the impeller, and the operating
parameters thereof, and such outflow section as to fully comply with the mechanical-interface
constraints and requirements set by the appliance in which the pump is due to be installed
and operate.
[0029] Figures 6A through to 6E are respective cross-sectional views of the delivery conduit,
as viewed along the respective section planes extending parallel to each other and
orthogonally to said axis C, from Pa to Pe in Figure 5. As it can be noticed in these
Figures, the available free passage area 9 of the delivery conduit, as identified
by the non-hatched sectors, increases in a gradual manner from a Figure to the next
one, corresponding exactly to the gradual increase in the cross-section area of the
same conduit.
[0030] Furthermore, and referring again to the same Figures 6A through to 6E, the side 7
that widens out inside the delivery conduit keeps in all cases having a substantially
planar contour, so as to be able to couple in a natural manner with the shape of the
inflow section S1 of the delivery conduit.
[0031] With particular reference to Figure 7, it is moreover particularly advantageous for
the pump body, which includes the pumping chamber 3 and the delivery conduit 2, to
be entirely provided as a single-piece unitary construction, so as to also include
said transition region of said delivery conduit having a gradually increasing cross-section
area.
[0032] The advantage deriving from such solution lies in the fact that, in this way, the
possibility is given for a pump body to be provided, which most advantageously combines
compact-size and high-efficiency characteristics, while complying with the requirements
set by the mechanical-interface design constraints described hereinbefore, this being
a result that can be obtained by providing said transition region within the delivery
conduit itself as a single-piece unitary construction therewith.
1. Centrifugal turbine pump comprising:
- an intake conduit (1),
- a delivery conduit (2),
- a pumping chamber (3),
- an impeller (4) housed in said pumping chamber,
- a plurality of vanes (5) arranged on and attached to said impeller,
said delivery conduit (2) comprising a transition region extending from the inflow
section to the discharge or outflow section (S2) thereof, and in that the cross-section
area of said delivery conduit increases along such transition region in a gradual,
continuous manner,
characterized in that the side (7) of said transition region lying closer to the axis (X) of said impeller
has a planar configuration.
2. Centrifugal turbine pump according to claim 1, characterized in that the contour (P) of the curve traced by the projection, on a plane extending orthogonally
to the axis (X) of rotation of said impeller, of the side of said transition region
(6) lying closer to the axis (X) of said impeller, comprises a point of inflection
(F).
3. Centrifugal turbine pump according to claim 2, characterized in that said delivery conduit gradually widens out in its cross-section to develop into such
shape that a projection thereof on a plane lying orthogonally to the axis of the impeller
would trace out a P-shaped contour P featuring two concavities (C1, C2), the first
one (C1) of which faces the exterior of the conduit with a vertex (V1), whereas the
second one (C2), with another vertex (V2), faces the interior of the same conduit.
4. Centrifugal turbine pump according to any of the preceding claims, characterized in that the portion of the pumping chamber (3) that houses said impeller is provided integrally,
i.e. as a single-piece unitary construction with said delivery conduit (2).
1. Zentrifugal-Turbinenpumpe, die umfasst:
eine Einlassleitung (1),
eine Förderleitung (2),
eine Pumpkammer (3),
ein Flügelrad (4), das in der Pumpkammer aufgenommen ist,
eine Vielzahl von Flügeln (5), die an dem Flügelrad angeordnet und daran angebracht
sind,
wobei die Förderleitung (2) einen Übergangsbereich umfasst, der von dem Einströmabschnitt
bis zu dem Ausstoß- oder Ausströmabschnitt (S2) derselben verläuft, und die Querschnittsfläche
der Förderleitung entlang dieses Übergangsbereiches allmählich kontinuierlich zunimmt,
dadurch gekennzeichnet, dass die Seite (7) des Übergangsbereiches, die näher an der Achse (X) des Flügelrades
liegt, einen planen Aufbau hat.
2. Zentrifugal-Turbinenpumpe nach Anspruch 1, dadurch gekennzeichnet, dass die Kontur (B) der Kurve, die durch die Projektion beschrieben wird, auf einer Ebene,
die sich senkrecht zu der Drehachse (X) des Flügelrades erstreckt, an der Seite des
Übergangsbereiches (6), die näher an der Achse (X) des Flügelrades liegt, einen Inflektionspunkt
(F) umfasst.
3. Zentrifugal-Turbinenpumpe nach Anspruch 2, dadurch gekennzeichnet, dass sich die Förderleitung in ihrem Querschnitt allmählich aufweitet und zu einer Form
wird, bei der eine Projektion derselben auf einer Ebene, die senkrecht zu der Achse
des Flügelrades liegt, eine P-förmige Kontur P beschreiben würde, die zwei Konkavitäten
(C1, C2) aufweist, deren erste (C1) der Außenseite der Leitungen mit einer Spitze
(V1) zugewandt ist, während die zweite (C2) mit einer weiteren Spitze (V2) der Innenseite
der gleichen Leitung zugewandt ist.
4. Zentrifugal-Turbinenpumpe nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass der Abschnitt der Pumpkammer (3), der das Flügelrad aufnimmt, integral als einteilige
Konstruktion mit der Förderleitung (2) vorhanden ist.
1. Pompe centrifuge à turbine comprenant:
- une conduite d'admission (1),
- une conduit de refoulement (2).
- une chambre de pompage (3),
- une roue (4) logée dans ladite chambre de pompage,
- une pluralité d'aubes (5) agencées sur et attachées à ladite roue,
ladite conduite de refoulement (2) comprenant une zone de transition s'étendant depuis
la section d'entrée de flux jusqu'à la section de décharge ou de sortie de flux (S2)
de celle-ci, et l'aire de la section transversale de ladite conduite de refoulement
augmente le long de ladite zone de transition d'une façon graduelle, continue,
caractérisée en ce que le côté (7) de ladite zone de transition se trouvant Plus prés de l'axe (X) de ladite
roue a une configuration plane.
2. Pompe centrifuge à turbine selon ta revendication 1, caractérisée en ce que le contour (P) de la courbe tracée par la projection, sur un plan s'étendant orthogonalement
à l'axe (X) de rotation de ladite roue, du côté de ladite zone de transition (6) se
trouvant plus prés de l'axe (X) dé ladite roue, comprend un point d'inflexion (F).
3. Pompe Centrifuge à turbine selon la revendication 2, caractérisée en ce que ladite conduite de refoulement s'élargit graduellement vers l'extérieur dans sa section
transversale pour se développer en une telle forme qu'une projection de celle-ci dans
un plan se trouvant orthogonal à l'axe de la roue tracerait un contour (P) en forme
de P présentant deux concavités (C1,C2), la première (C1) de celles-ci faisant face
à l'extérieur de la conduite avec un sommet (V1), tandis que la seconde (C2), avec
un autre sommet (V2), fait face à l'intérieur de la même conduite.
4. Pompe centrifuge à turbine selon l'une quelconque des revendications précédentes,
caractérisée en ce que la portion de la chambre de pompage (3) qui loge ladite roue est fournie intégralement,
c'est-à-dire comme une construction unitaire en une pièce unique avec ladite conduite
de refoulement (2).