FORM-2 THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL
(See section 10 and rule 13)


AN IMPELLER MOUNTED 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 mounted on the pump shaft.
More particularly this invention relates to the wear rings fitted on either side of an impeller mounted 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 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.
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In a roto-dynamic pump the impeller is located on the pump shaft and rotates at high speed. In split case pumps two rings are fitted on either side of the impeller to protect the pump casing from wear caused by fluid flow. The rings are generally referred to as case-wear rings.
In a horizontal split case type pump these case-wear rings are initially fitted on impeller. A reamed hole is provided on the lower half casing centre to hold the casing ring. A dowel pin provided on the case-wear ring locates the assembly accurately in the pump casing.
During assembly of the pump, the sub assembly consisting of the pump shaft, bearings and the impeller along with the case-wear ring is lowered into the lower half of the pump casing. When this sub assembly rests on the lower pump casing half it has to be carefully maneuvered to locate the pin provided on the case-wear ring, in the reamed hole provided on the inner surface of the lower pump casing. This requires high amount of skill to prevent possible damage to the locating pin as both the pin and the reamed hole are not visible to a person carrying out the assembly. Fitting of the upper pump casing will also have to be carried out without having any visibility of the dowel pin and the hole provided on the upper half of the case ring and pump casing respectively.
In view of the above difficulty there is a need to develop case-wear ring which is easily fitted in the pump casing.
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OBJECTS OF THIS INVENTION:
One of the objects of this invention is to provide a case-wear ring for a split case pump that can be assembled quickly.
Another object of this invention is to provide for a split case pump that can be assembled and dismantled even by unskilled personnel.
Yet another object of this invention is to provide case-wear ring for a split case pump that can be dismantled and reassembled without the use of expensive tools and instruments.
Yet another object of this invention is to provide case-wear ring for a split case pump that can be easily manufactured.
Still another object of this invention is to provide case-wear ring 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 a conventional impeller and case- wear ring assembly for a split case pump; and
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Figure 2 is the perspective view of a conventional split case pump with the upper half casing removed.
Figure 3 is a perspective view of the impeller and case- wear ring assembly of this invention.
DETAILED DESCRIPTION OF THE DRAWINGS:
Referring to Figure 1, conventional impellers 14 and case- wear rings 12 on either side of the impellers 14, for a split case pump of the prior art are shown. Impellers 14 and case-wear ring 12 are located on the pump shaft 16. Dowel pins 18 are located in the operative top and bottom portion of the case-wear rings 12.
Referring to Figure 2 a split case pump as per this invention is indicated generally by the reference numeral 100. The split case pump 100 is provided with impellers 20 and case-wear rings 22. The dowel pins (refer figure 3) are provided on the operative horizontal axis of the pump casing. This arrangement facilitates easy and quick assembly of the impellers, case-wear rings along with the pump shaft in the lower half of the pump casing. Similarly locating of the top half (not specifically shown) of the split case pump is done with full visibility of both the dowel pins and complementary dowel pin holes.
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.
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These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the 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.

ith
Dated this 24th day of June 2008.

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

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