Note: Descriptions are shown in the official language in which they were submitted.
CA 02612471 2007-12-17
Water Pump
The invention concerns a water pump, in particular for use in garden ponds and
in the field of aquaristics, according to the preamble of claim 1.
In practice, pumps are common in this field that have a motor-driven radial
impeller so that the water to be pumped is deflected by a deflection angle of
90
degrees. In this way, these pumps fulfill the existing requirements with
regard to
the particular configurations according to which a deflection by approximately
90
degrees must generally occur. Even though such water pumps generate a
relatively high delivery pressure, they have a relatively small delivery rate.
If it is
desired to achieve with such a pump a great delivery rate, the required power
input is very high.
It is therefore an object of the present invention to provide a water pump
with
improved efficiency with regard to the delivery rate. This object is solved
according to the invention by a water pump having the features of claim 1.
By using a pump impeller that is embodied as a diagonal impeller with a
substantially conical carrier plate, the flow is guided diagonally through the
impeller and is deflected by a smaller angle in comparison to a radial
impeller.
When conveying large quantities of water, the deflection losses remain small
and
the efficiency is improved. Pumps designed in this way have the advantage that
at reduced pressure more water volume can be conveyed. Preferably, such
pumps are therefore used in filter devices where little pressure but a high
flow
rate are required. By means of the improved efficiency, the pump according to
the invention requires significantly less power input than the known pumps
with a
radial impeller. Also, the pump according to the invention with its great flow
rate
efficiency can be built more compact than pumps with conventional impellers.
In
order to obtain the same flow rate, the diameter of a conventional impeller
would
have to be greater by a factor 1.5. The compact configuration of the pump
according to the invention enables also an especially cost-efficient
manufacture
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CA 02612471 2007-12-17
because only relatively small tools, in particular, injection molds for
plastics, are
required.
Further advantages and details result from the dependent claims and an
embodiment illustrated in the drawings that will be explained in the
following; it is
shown in:
Fig. 1 a water pump according to the invention in longitudinal section; and
Fig. 2 the pump impeller of the pump of Fig. 1 in a perspective exploded view.
The illustrated water pump has a pump housing 1 and a motor housing 2
connected thereto in a seal-tight way; together they form the complete housing
of
the pump. The pump housing 1 has a water inlet 3 and a water outlet 4 which
are preferably centrally arranged on the top side of the pump housing. In the
interior of the pump housing 1 between the water inlet 3 and water outlet 4
the
pump impeller 5 configured as a diagonal impeller is arranged. The latter is
shown in Fig. 2 in a perspective view.
The pump impeller 5 has according to the present invention a substantially
conical carrier plate 6 by which the water flow, indicated by the arrows 7, is
guided diagonally through the pump housing. In cooperation with the
arrangement and shape of the water inlet 3 and the water outlet 4, preferably
arranged essentially perpendicular to one another, the water flow 7 exits the
pump in a direction deflected by approximately 90 degrees relative to the
intake
direction of the water flow 7. The carrier plate 6 of the pump impeller 5
defines a
cone angle a of preferably 80 degrees to 100 degrees. In this way, an optimal
flow deflection is achieved and the flow losses are minimized.
The illustrated embodiment is especially advantageous because the outer blade
edges 8 of the impeller blades 9 extend in the diagonal direction, parallel to
the
direction of the water flow 7, and to the surface of the carrier plate 6. In
this way,
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CA 02612471 2007-12-17
the impeller blades 9 can be matched to the contour of the stationary pump
housing 1 so that they form a seal gap 10 thereat. In this special
configuration, it
is possible to provide with standard tolerances of the components a tight seal
gap 10 between the stationary pump housing 1 and the rotating impeller 5. This
leads to a minimal inner leakage flow and thus to an improved hydraulic
efficiency. The pump can be designed especially compact when the seal gap 10
is arranged in the transition area between the water inlet 3 and the water
outlet 4.
The pump of the illustrated embodiment is optimized with regard to its flow
behavior and its smooth running in that the impeller blades 9 have an airfoil
profile and the carrier plate 6 of the pump impeller 5 has a pointed rear edge
13.
An excellent flow distribution when the flow is directed against the pump
impeller
5 is achieved moreover in that the leading edges 14 of the impeller blades 9
facing the flow are oriented substantially perpendicularly to the flow
direction of
the water in the water inlet 3.
Centrally within the cone tip of the carrier plate 6 of the pump impeller 5
there is
preferably a penetration 15 or a bore serving for cooling and venting
purposes.
The pump impeller 5 can be produced particularly cost-efficient as an
injection-
molded plastic part. In order to optimize wear and gliding properties,
preferably a
metal ring is embedded by injection molding and serves as a bearing
receptacle.
The metal ring 16 is shown behind the shaft 17 in the exploded view of Fig. 2;
however, in the assembled component it is arranged within the shaft 17. By
means of the metal ring 16, the pump impeller 5 is supported on an electric
motor
18 and is driven by the motor in rotation.
The water pump according to the invention is excellently suitable because of
its
compact configuration, its high conveying output and its minimal power input
as a
circulating pump primarily for applications in which a permanent operation is
required. In comparison to conventional pumps, significant energy savings are
achieved.
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