AU677347B2

AU677347B2 - A liquid pump

Info

Publication number: AU677347B2
Application number: AU70254/94A
Authority: AU
Inventors: Reinhold Hopfensperger; Rudolph Tungl
Original assignee: Alcatel SEL AG
Current assignee: Motoren Ventilatoren Landshut GmbH
Priority date: 1993-08-27
Filing date: 1994-08-15
Publication date: 1997-04-17
Anticipated expiration: 2014-08-15
Also published as: DE4328861A1; AU7025494A; EP0640767A1

Description

v/ P/00/011 28/5/91 Regulation 3.2

AUSTRALIA

Patents Act 1990 *000 0

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: "A LIQUID PUMP" The following statement is a full description of this invention, including the best method of performing it known to us:- 00 0 0 0. 0 00900 III-- r This invention relates to a liquid pump which is driven by an electric motor.

Such a pump is known. The known pump has a two-part plastic casing.

The impeller, which is rotatably mounted in the casing, is driven by an electric motor mounted on the casing.

The known pump is a small centrifugal pump of the radial-flor type. In such pumps, the axially sucked water is accelerated by the individual vanes of the impeller and discharged radially outward to the existing pressure space. The fluid leaving this pressure space has given energy which can be separated into a static component and a dynamic component. At a high back pressure, for example, the dynamic component is very small, while the static component is the determining factor, Because of the small dynamic component of the energy of the fluid, the volume flow is low.

e The energy of flow stems from the kinetic energy of the impeller which was transmitted to the water. In passing through the impeller, the water is accelerated by the vane only once. This means that with unchanged impeller geometry, the energy transfer from the impeller to the fluid can only be increased via the peripheral velocity. This is possible by increasing either the speed or the diameter of the impeller. With the commonly used shaded-pole motors (asynchronous motors) or synchronous motors, the speed can only be increased by increasing the frequency, which adds significantly to the cost of the pump. A greater impeller diameter inevitably results in greater pump dimensions.

The technical problem underlying the invention is to provide a pump of the above type which has a higher capacity with unchanged impeller dimensions and unchanged impeller speed, the rated capacity is to"be increased.

According to the invention, there is provided an electric driven liquid pump comprising a flat casing consisting of a bottom and a cover; an impeller in the interior of the casing which is drivable by the electric motor; a circular suction inlet in the cover;

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_I the impeller consists of a circular disk with vanes formed integrally thereon, and along the circumference of the interior of the casing, a channel is provided behind the impeller.

The fundamental idea of the solution according to the invention is to lead the liquid, after acceleration by a vane of the impeller, back to the impeller in order to accelerate it again by another vane. In this manner, multiple energy transmission from the vanes of the pump to the liquid takes place before the latter leaves the pump casing.

The invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a section through the novel pump taken along line C-D or Figure 2; :o Figure 2 is a section taken along line A-B of Figure 1; Figure 3 is a section through the cover of the casing taken along line .o E-F of Figure 4; Figure 4 is a section taken along line G-H of Figure 3; Figure 5 is a tcp view of the vane side of one embodiment of the impeller; Figure 6 is a side view of the impeller of Figure 5, and Figure 7 is a top view of the vane side of another embodiment of the impeller.

t As can be seen in Figure 1, the pump casing consists of the bottom 1 and the cover 2. The impeller 3, whose hub 4 is driven by an electric motor (not shown) is rotatably disposed in a hollow space between bottom 1 and cover 2. Along the circumference of the interior of the casing, a channel 5 is provided behind the impeller 3. As can be seen in Figures 1 and 2, the channel has a cross section which continuously increases from its narrowest point at 6 to the delivery connection 7. The channel may also have a uniform cross section over its entire length.

The pump shown works as follows. With the impeller 3 driven, the liquid particles are sucked axially through the suction inlet in the cover 2 into the r I impeller 3. In passing diagonally through the impeller 3, the liquid particles receive energy from the vanes 9 and are thereby moved to the outer wall of the channel 5 behind the impeller 3. After a reversal of the direction of flow in the channel 5 and re-entry of the liquid into the vane channels, the liquid particles are accelerated again. The superposition of a velocity component in the circumferential direction on this circular motion of the liquid particles results in a volute flow through the channel 5 up to the delivery connection 7, with the liquid particles being accelerated several times. The flow of the liquid is indicated in Figu'gs 1 and 2 by the lines 8.

Figures 3 and 4 illustrate the shape of the pump cover 2. Figures 5 and 6 show one embodiment of the impeller 3. Figure 5 shows that the impeller 3 has a number of vanes 9 which are curved backward. Arrow 10 indicates the direction of rotation of the impeller 3. As can be seen in Figure 6, the vanes 9 are connected with a circular disk 1 1 which, in turn, is connected with the hub 15: 4. The diameter of the circular disk 11 is less than that of the circle formed by the outer rims of the vanes 9, about one-half of the vane length is cantilevered. The length of the inner edge 12 of the vanes 9 is greater than the length of the outer edge 13, since the edge 14 is inclined.

°o o Figure 7 shows another embodiment of the impeller 3. This impeller has vanes 15 which extend in a radial direction at their ends. The direction of rotation of the impeller 3 is indicated by arrow 16.

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Claims

1. An electric-motor-driven liquid pump comprising; a flat casing having a bottom and a cover; an impeller in the interior of the casing which is drivable by the electric motor; a circular suction inlet in the cover; the impeller comprises of a circular disk with vanes formed integrally thereon, and along the circumference of the interior of the casing, a single channel is provided behind the impeller.

2. A pump as claimed in claim 1, wherein the vanes project beyond the edge6 of the circular disc.

3. A pump as claimed in claims 1 or 2 ,wherein the vanes of the impeller are curved backward. :15

4. A pump as claimed in claims 1 or 2, wherein the vanes of the impeller extend in a radial direction at their ends.

A pump as claimed in any one of the preceding claims, wherein the channel has a cross section increasing in the circumferential direction.

6. A pump as claimed in any one of the preceding claims, wherein the length of the vanes at the disc is greater than that at the outer edge.

7. A pump substantially as herein described with reference to Figures 1 7 of the accompanying drawings. DATED THIS FOURTH DAY OF FEBRUARY 1997 ALCA TEL SEL A.G. I I -I I _I -b -I ABSTRACT The invention relates to the provision of a small centrifugal pump which has a higher capacity than conventional small centrifugal pumps with unchanged dimensions and unchanged speed of the impeller. In the novel centrifugal pump, a channel is provided behind the impeller into which the liquid particles are forced. The liquid particles, moving in the channel along a volute path, are accelerated by the impeller vanes several times. (Figure 1) e .e. 0S@O o* 0 C S 5* C C.. o oo Se *SC S eC e 6 w S I L