AU2013100633A4 - Improved centrifugal pump impeller - Google Patents

Abstract

This invention relates to design of centrifugal pump impeller and includes an improved impeller and a method of design of impeller for centrifugal pump. The invention involves a different approach to the design of an impeller. Instead of having the outside diameter of vanes and cross-section of sub chambers being fixed, it utilizes the varying external pressure and centrifugal force to control at least one of these elements. Figure 2 Fig.1 3 - Fig.2 TOD

Description

AUSTRALIA Patents Act 1990 SPECIFICATION PROVISIONAL PATENT IMPROVED CENTRIFUGAL PUMP IMPELLER The following statement is a full description of this invention, including the best method of performing it known to us: 1 IMPROVED CENTRIFUGAL PUMP IMPELLER FIELD OF THE INVENTION [0001] This invention relates generally to impellers for centrifugal pumps. In one for, the invention relates to and has particularly useful application to swimming pool pumps. It will be convenient to hereinafter describe the invention in relation to a swimming pool pump; however it should be appreciated that the present invention is not limited to that use only. [0002] Throughout this specification, the term "centrifugal pump" includes in its ambit any kind of pump that uses a rotating impeller to increase the pressure and flow rate of a fluid. [0003] Throughout this specification, the term "impeller" includes in its ambit any kind of a rotating component of a centrifugal pump which transfers energy from the motor to the fluid. BACKGROUND OF INVENTION [0004] Centrifugal pumps use a rotating impeller to increase the pressure and flow rate of a fluid. The fluid usually enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward or axially into a diffuser or volute chamber, from where it exits into the downstream piping system. [0005] Impellers transfer energy from the motor that drives the pump to the fluid being pumped by accelerating the fluid outwards from the center of rotation. The velocity achieved by the impeller transfers into pressure when the outward movement of the fluid is confined by the pump casing.

2 [0006] Impellers are usually short cylinders with an open inlet (called an eye) to accept incoming fluid, vanes to push the fluid radially, and a splined, keyed or threaded bore to accept a drive-shaft. [0007] Impellers can be open, semi-open, or enclosed. The open impeller consists only of blades attached to a hub. The semi-open impeller is constructed with a circular plate attached to one side of the vanes. The enclosed impeller has circular plates attached to both sides of the vanes. [0008] The majority of pool pumps have an enclosed impeller as it provides better pressure compared to the open or semi-open impeller. [0009] The impeller chamber of an inclosed impeller is formed between circular plates and subdivided into subchambers by the vanes. The majority of inclosed impellers are made of plastic, iron, steel, bronze, brass or aluminium. Circular plates are usually secured to the edges of the vanes and therefore the size of subchambers is fixed, as well as diameter of impeller and the distance between circular plates. [0010] Performance and efficiency of an enclosed impeller depends on its design, especially on the outside diameter of vanes and on the cross-section of sub chambers (defined by the hight of vanes and the distance between circular plates). The larger the cross section of the sub chambers of an impeller become the higher the flow rate becomes. But as this increases so does the power required to operate the impeller in the restricted system compared to the impeller with a smaller cross-section of sub chambers. Impellers with bigger diameters create better pressure but they are less efficient in systems with low restriction. [0011] Pool pumps can be used for different functions such as filtration, vacuuming, backwashing, operating waterfall etc. Each function requires a different performance. For example backwashing requires low flow and high pressure however filtering requires high flow and low pressure.

3 [0012] Most pool systems are equipped with filters, leaf canisters, skimmer boxes etc. in order to keep the water in the pool clean. Over time these components become more restrictive due to collected leafs, hairs, debris etc., therefore restriction of the pool system is not constant. It varies over time and the performance demand varies accordingly. [0013] Pool pumps are commonly single speed pumps. It is also common for one pump to run an entire pool system, from filtration to vacuuming. In view of this fact most pumps are designed to handle the high pressure demand. They usually have thinner impellers with a bigger diameter which is better for creating higher pressure. This impeller design results in a less efficient operation of the pump under low pressure, especially when the pump is used for the filtering. This issue has been partly addressed recently with the development of Multi-speed pumps and variable speed pumps. These pumps can be run at different speeds within a set range. These pumps are limited though in the fact that the impeller can not be optimal for all functions.

4 SUMMARY OF THE INVENTION [0014] It is an object of embodiments of the present invention to provide a more efficient impeller by enabling it to provide better water flow or create more pressure. [0015] The invention involves a different approach to the design of an impeller. Instead of having the outside diameter of vanes and cross-section of sub chambers being fixed, it utilizes the varying external pressure and centrifugal force to control at least one of these elements. [0016] In essence, the present invention stems from the realization that since performance demands vary, the dimensions of an impeller also need to vary in order to improve performance at all times during all functions. BRIEF DESCRIPTION OF THE DRAWINGS [0017] The invention now will be further described, by way of example only, with reference to the accompanying drawings. In this respect, further disclosure, objects, advantages and aspects of preferred and other embodiments of the present application may be better understood by those skilled in the relevant art by reference to the following description of embodiments taken in conjunction with the accompanying drawings, which are given by way of illustration only, and thus are not limitative of the disclosure herein, and in which: [0018] Figurel is a schematic perspective view of impeller; [0019] Figure2 is a schematic side-view of impeller according to the present invention.

5 DETAILED DESCRIPTION OF THE EMBODIMENTS [0020] An impeller in accordance with this invention comprises two circular plates, 1 and 2 with an open inlet. There are vanes 3 between plates. At least one part or one area of impeller is able to move or able to deform or able to deform and move in order to change cross-section of sub chambers CS or to change the working outside diameter of vanes OD or to change both CS and OD. [0021] To insure the ability to deform or move at least one part of the impeller or at least have one area of any part of the impeller made from a deformable material or incorporate at least one additional deformable element [0015] In a first aspect of embodiments described herein there is provided a method of design of impeller having at least the working outside diameter of vanes OD or cross-section of sub chambers CS controlled by external pressure or centrifugal force or by external pressure and centrifugal force together. [0022] In the second aspect of embodiments described herein there is provided a design of impeller having cross-section of sub chambers CS constantly varying as a direct result of changing pressure acting on the impeller. If the pressure in the outlet increases the cross-section of sub chambers decreases and vice versa. [0023] In the third aspect of embodiments described herein there is provided a design of impeller having the working outside diameter of vanes OD constantly varying as a direct result of varying speed of the driving motor. If the speed of the motor increases the outside diameter of vanes increases and vice versa. [0024] In the fourth aspect of embodiments described herein, a design of impeller having cross-section of sub chambers CS and the working outside diameter of vanes OD that is constantly varying as a direct result of changing pressure acting on the impeller and as a direct result of varying speed of the driving motor. If the pressure in the outlet increases or the speed of the motor increases the cross- 6 section of sub chambers CS decreases or the working outside diameter of vanes OD increases and vice versa.

Claims (4)

1. Impeller for centrifugal pump comprising: at least one circular plate with an open inlet to accept incoming fluid; at least one circular plate with a bore to accept a drive-shaft; vanes between plates to push the fluid radially, subdividing the impeller chamber formed between plates into sub chambers vanes, wherein at least one part of impeller and/or at least one area of impeller is arranged to move and/or able to deform in order to change cross-section of sub chambers and/or to change the working outside diameter of vanes.

2. Impeller as claimed in claim 1 wherein the working outside diameter of vanes controlled by external pressure or centrifugal force or by external pressure and centrifugal force together.

3. Impeller as claimed in claim 1 wherein the cross-section of sub chambers controlled by external pressure or centrifugal force or by external pressure and centrifugal force together.

4. A method of designing of impeller comprising the steps of: arranging at least one part of impeller and/or at least one area of impeller to be able to move and/or able to deform in order to change cross-section of sub chambers and/or to change the working outside diameter of vanes; enabling the external pressure and/or the centrifugal force to control working outside diameter of vanes and/or the cross-section of sub chambers. Aaron Marshall, Erik Karaim 9.05.2013 (Name of Applicants) (Date)