FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION An improved nozzle
APPLICANT (S)
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR (S)
Desale Rajgopal Shivdas, of Crompton Greaves Ltd, S3, Switchgear Division, A3, MIDC Ambad, Nashik-422010
PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

Field of the Invention:
This invention relates to the field of mechanical devices and material science.
Particularly, this invention relates to the field of nozzles. More particularly, this invention relates to an improved nozzle.
Background of the invention:
Basically, a nozzle is a device designed to control the direction or characteristics of a fluid flow (especially to increase velocity) as it exits (or enters) an enclosed chamber or pipe via an orifice. Nozzles are usually used to control the flow of fluid passing through it. In some hydro-applications, it may be used to create a channeled flow of hydro-fluid. These may result in cleaning applications. While in some other gas-applications, it may be used to create a vortex output. This may aid laser arc cutting tools.
A nozzle is used in an interrupter for blowing / blasting the gas (SF6 or other) during interruption. Hence, design of nozzle is very critical. There are some important functions to be fulfilled by nozzle such as guiding the gas, ablation and withstanding high temperature during operation. Existing nozzle designs have two distinct shapes; one is for guiding the gas without ablation and other is with ablation.
Currently two different types of materials for nozzle designs are being used i.e. (1) PTFE (2) MOS2. Both the designs have unique purposes. PTFE is less helpful for ablation and more helpful for smooth flow of gas. MOS2 is

more helpful for ablation and less helpful for smooth flow of gas. Profile of both the materials is also unique.
While selecting only one material, the advantages that could be obtained from the other material are lost.
There is a need for a better nozzle design which incorporates both the advantages at appropriate portions.
Objects of the Invention:
An object of the invention is to obtain the advantages of a first material, for a nozzle, which aids ablation.
Another object of the invention is to obtain the advantages of a second material, for a nozzle, which aids smoother flow of gas.
Yet another object of the invention is to obtain the advantages of a first material, for a nozzle, which aids ablation and a second material, for a nozzle, which aids smoother flow of gas; simultaneously.
Summary of the Invention:
According to this invention, there is provided an improved nozzle having an input region, a throat region, and an output region, said nozzle comprises: replaceable annular ring with inward teethed projections being projected towards the centre, said inward teethed projections adapted to be angularly displaced and said ring adapted to fit before said throat region of said nozzle in order to impart ablation characteristics to said nozzle, in that, said teeth

projections being made of ablation imparting material, and said nozzle being lined interiorly with smooth flow imparting material.
Preferably, said teethed projections are spaced apart, about said ring, at an angle of 120° with respect to each other, thereby providing three teethed projections around the inner diameter of said annular ring. There can be alternate arrangement of projections e.g. 90 degree apart or 30 degree apart.
Alternatively, said teethed projections are spaced apart, about said ring, at equally defined angles with respect to each other, thereby providing multiple teethed projections around the inner diameter of said annular ring.
Typically, said teethed projections are ablation pads made of MOS2.
Preferably, said teethed projections are ablation pads made of PTFE+MOS2 (MOS2 is 2 % to 4% with respect to PTFE).
Typically, inner lining of said nozzle made of PTFE material.
Typically, said replaceable ring is a threaded ring adapted to thread said ring near said throat region.
Alternatively, said teethed projections are removable teethed projections.
Brief Description of the Accompanying Drawings:
Figure 1 illustrates a schematic of the equipment in which a nozzle is installed;
Figure 2 illustrates an existing nozzle design of the prior art; and

Figure 5a illustrates a flow diagram for gas output for a nozzle of the prior art (100).
The invention will now be described in relation to the accompanying drawings, in which:
Figure 3 illustrates an improved nozzle according to this invention;
Figure 4 illustrates a graphical analysis for pressure plot of ablation characteristics of MOS2 versus PTFE; and
Figure 5b illustrates a flow diagram for gas output for an improved nozzle of Figure 1.
Detailed Description of the Accompanying Drawings:
Figure 1 illustrates a schematic of the equipment in which a nozzle is installed.
Reference numeral 12 refers to a piston. Reference numeral 14 refers to a fixed finger contact. Reference numeral 16 refers to a puffer cylinder. Reference numeral 18 refers to a moving arc contact. Reference numeral 22 refers to a moving main contact. Reference numeral 24 refers to a stationary arc contact. Reference numeral 26 refers to stationary main contact. Reference numeral 100 refers to a nozzle.
Figure 2 illustrates an existing nozzle design of the prior art as referenced by numeral 100. The use of a nozzle is necessitated in equipment where arching is required, wherein highly pressurised gas is required to be output. The

orifice of the nozzle should output gas (according to this equipment) which has high pressure. The channel that delivers the gas from an input (of the equipment of Figure 1) to the orifice output (32) is made in a manner that there is a pressure rise from the input to the output. This is generally done by constricting the flow of gas, from a relatively broader input portion to a relatively narrower output portion, by means of a throat portion (34). As the gas flows from the broad portion into the narrow portion, naturally, pressure increases. The material used in the internal channel of such nozzles is either PTFE or MOS2. PTFE is less helpful for ablation and more helpful for smooth flow of gas. MOS2 is more helpful for ablation and less helpful for smooth flow of gas. Profile of both the materials is unique. However, if the material gets eaten away, there is a drop in pressure and performance decreases, thereby. The curve (36) which blends to form the junction or transition from the relatively broader portion of the nozzle interior to the relatively narrower portion of the nozzle interior is of critical importance to impart the required or designed pressure rise. The deterioration of the nozzle interior at this crucial juncture due to high incidence of gases cannot be arrested. It can be remedied only by replacing the nozzle, entirely. The disadvantages of the nozzle design of the prior art is that there is only one material that can be used at a time; either PTFE or MOS2, thereby providing only one function of smoother flow or higher ablation of the gas. The pressure rise is consequently poor and there may be clogging at the throat area.
According to this invention, there is provided an improved nozzle,

Figure 3 illustrates a nozzle according to this invention.
In accordance with an embodiment of this invention, there is provided a
replaceable annular ring (40) with inward teethed projections (42) being
projected towards the centre. The inward teethed projections adapted to be
angularly displaced before the throat region of said nozzle in order to impart
ablation characteristics to the nozzle. The teethed projections may be spaced
apart at an angle of 120° with respect to each other, thereby providing three
teethed projections around the inner diameter of the annular ring. Typically,
these teethed projections are ablation pads made of MOS2 or MOS2 and
PTFE with 2% to 4% of PTFE in it. The inner lining of the nozzle is,
otherwise, made up on PTFE material which is a non-ablation material and
provides a smoother laminar flow profile for the gas.
This annular ring is replaceable or detachable. As ablation occurs, the pads deplete in height, and this depletion may be sensed by fall in pressure of the output gas. Now, only the ring with pads needs to be replaced. Alternatively, the pads may be replaceable themselves, thereby retaining the ring. As newer pads are now fixed, the ablation characteristics of the nozzle, can be restored without requiring the need to completely change and / or dispose the nozzle. The threaded joint (35) can be seen where the external threads (37) of the annular ring mate.
This additional piece has a shape which can be molded using a plastic mould. This shape (combined profile of smooth flow and raised pad for ablation) is easy to achieve in mould. These two pieces can be joined

together by threaded joint and with adhesive material. After curing, it becomes single piece.
The invention will now be explained in relation to an exemplary embodiment.
Figure 4 illustrates a graphical analysis for pressure plot of ablation characteristics of MOS2 (represented by blue plot) versus PTFE (represented by red plot).
Figure 5a illustrates a flow diagram for gas output for a nozzle of the prior art (100).
Figure 5b illustrates a flow diagram for gas output for a nozzle of this invention (200).
It was observed that improvement in pressure was generated in puffer due to modification in nozzle for ablation. Pressure built at current zero is important. There was 44% improvement in pressure at current zero instance. This analysis was done in MC3 software which is specially developed software for breaker- interrupter design study in terms of pressure, velocity, temperature, etc.
While this detailed description has disclosed certain specific embodiments of the present invention for illustrative purposes, various modifications will be apparent to those skilled in the art which do not constitute departures from the spirit and scope of the invention as defined in the following claims, and 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.

We claim,
1. An improved nozzle having an input region, a throat region, and an
output region, said nozzle comprising:
replaceable annular ring with inward teethed projections being projected towards the centre, said inward teethed projections adapted to be angularly displaced and said ring adapted to fit before said throat region of said nozzle in order to impart ablation characteristics to said nozzle, in that, said teeth projections being made of ablation imparting material, and said nozzle being lined interiorly with smooth flow imparting material.
2. A nozzle as claimed in claim 1 wherein, said teethed projections are spaced apart, about said ring, at an angle of 120 with respect to each other, thereby providing three teethed projections around the inner diameter of said annular ring.
3. A nozzle as claimed in claim 1 wherein, said teethed projections are spaced apart, about said ring, at an angle of 30° with respect to each other, thereby providing twelve teethed projections around the inner diameter of said annular ring.
4. A nozzle as claimed in claim 1 wherein, said teethed projections are spaced apart, about said ring, at an angle of 90 with respect to each other, thereby providing four teethed projections around the inner diameter of said annular ring.

5. A nozzle as claimed in claim 1 wherein, said teethed projections are spaced apart, about said ring, at equally defined angles with respect to each other, thereby providing multiple teethed projections around the inner diameter of said annular ring.
6. A nozzle as claimed in claim 1 wherein, said teethed projections are ablation pads made of MOS2.
7. A nozzle as claimed in claim 1 wherein, said teethed projections are ablation pads made of MOS2 and PTFE with 2% to 4% of MOS2 in it.
8. A nozzle as claimed in claim 1 wherein, inner lining of said nozzle made of MOS2 material.
9. A nozzle as claimed in claim 1 wherein, said replaceable ring is a threaded ring adapted to thread said ring near said throat region.
10.A nozzle as claimed in claim 1 wherein, said teethed projections are removable teethed projections which enhance overall life of nozzle there by replacing damaged nozzle inner ring due to ablation over period of time.