FORM-2 THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL
Specification
(See section 10 and rule 13)
AN IMPELLER FITTED ON THE PUMP SHAFT


KIRLOSKAR BROTHERS LIMITED
an Indian Company
of Udyog Bhavan, Tilak Road, Pune 411 002,
Maharashtra, India

THE FOLLOWING SPEC IFICATION DESCRIBES THE INVENTION.


FIELD OF THE INVENTION; This invention relates to a pump.
Particularly, this invention relates to an impeller fitted on the pump shaft.
INTRODUCTION:
A pump is a device used to move liquids from any source location to another location for storage or consumption. Pumps work by using mechanical forces to push the fluid material, by physically lifting, by the force of compression or by centrifugal force.
Pumps fall into two major groups called roto-dynamic pumps and positive displacement pumps. Roto-dynamic pumps are based on bladed impellers which rotate within the fluid to impart a tangential acceleration to the fluid and a consequent increase in the energy of the fluid. The purpose of the pump is to convert this energy into pressure energy of the fluid to be used in the associated piping system,
A positive! displacement pump causes a liquid or gas to move by trapping a fixed amount of fluid or gas and then forcing (displacing) that trapped volume into the discharge pipe.
In a roto-dynamic pump the impeller is located on the pump shaft and rotates at high speed. The location of the impeller on the shaft is very critical as any error in locating the impeller will lead to dynamic imbalance and incorrect clearance between the pump casing and the impeller. A factory fitted
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impeller is accurately located on the shaft and delivers the rated volumetric and pressure capacity of the pump. In a split case pump the impeller is located between bearings and a sleeve is used to locate the impeller. The sleeve also protects the pump shaft. The sleeve is required to be replaced due to wear as it is located in the gland region of the pump. When the sleeve is

dismantled

for replacement the impeller location gets disturbed.

On reassembly, accurately locating the impeller on the shaft is a time consuming and skilled work. Any error in the location of the impeller causes several problems like vibration leading to bearing damage and drop in hydraulic performance of the pump.
It is also difficult to verify the impeller location accurately at site conditions as required tools and measuring instruments are not easily available and if available are not properly calibrated to ensure the required accuracies. This results in a trial and error type of pump reassembly causing delay in commissioning of the pump.

OBJECTS

OF THIS INVENTION:

One of the

objects of this invention is to provide an impeller assembly for a

split case pump that can be dismantled and reassembled quickly.
Another object of this invention is to provide an impeller assembly for a split case pump that can be dismantled and reassembled even by unskilled personnel.
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Yet another object of this invention is to provide an impeller assembly for a split case pump that can be dismantled and reassembled without affecting the rated hydraulic performance of the pump.
Yet another object of this invention is to provide an impeller assembly for a split case pump that can be dismantled and reassembled without the use of expensive and calibrated tools and measuring instruments.
Yet another object of this invention is to provide an impeller assembly for a
split case pump that can be easily manufactured.
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Yet another object of this invention is to provide an impeller assembly for a split case pump that is inexpensive to manufacture.
BRIEF DESCRIPTION OF THE DRAWINGS:
The invention will now be described with respect to the accompanying drawings in which:
Figure 1 is a perspective view of conventional impeller assembly for a split case pump; and
Figure 2 is the perspective view of impeller assembly as per this invention for a split case pump.
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DETAILED DESCRIPTION OF THE DRAWINGS:
Referring to Figure 1 a conventional impeller assembly for a split case pump of the prior art is shown. Impeller 12 is located on the pump shaft 16 by a removable sleeve 14. The sleeve 14 is located in the gland region of the pump and is in rubbing contact with the gland material to achieve leak tight connection between the shaft 16 and the casing of the pump (not specifically shown). The sleeve 14 gets worn out in use and has to be replaced. As the sleeve 14 is dismantled the impeller 12 becomes dislocated with reference to the shaft 16. On reassembly, it becomes very difficult to locate the impeller 12 accurately on the shaft 16.
Figure 2 is the impeller assembly as per this invention wherein a locator 20 holds the impeller 18 firmly on the pump shaft 26 and a sleeve unit 22 is fitted abutting the locator 20. During dismantling and replacement of the sleeve 22 the impeller 18 remains rigidly attached to the shaft 26, thereby its original and accurate factory fitted location is maintained. This leads to quick replacement of the worn out part reducing down time, avoids the need for skilled fitters and the hydraulic performance of the pump remains unaffected.
While considerable emphasis has been placed herein on the various components of the preferred embodiment, it will be appreciated that many alterations can be made and that many modifications can be made in the preferred embodiment without departing from the principles of the invention. These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the
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art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

,th
Dated this 24thday of June 2008.

Mohan Dewan of R. K. Dewan & Co Applicants' Patent Attorneys

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