FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
AND
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2005
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
Interconnecting pump mechanism between a transformer and radiator
APPLICANTS :
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Ivlumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR (S):
Singh Aditya, of Crompton Greaves Ltd, Transformer (T3) Division, Plot No 29, 31 and 32, New Industrial Area No 1 AKVN, Manideep, 462046, Madhya Pradesh, India; an Indian National.
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 transformers, radiators and interconnecting mechanisms thereof.
Particularly, this invention relates to an interconnecting pump mechanism between a transformer and radiator.
Background of the Invention:
A transformer is an electric device which transfers current from one circuit to another with or without affecting its magnitude. It includes electro-mechanical assemblies such as copper windings immersed in oil.
Power transformers rated up to a few KVA can be adequately cooled by natural convective air-cooling, sometimes assisted by fans. Some power transformers are immersed in specialized transformer oil that acts both as a cooling medium, thereby extending the lifetime of the insulation transformer. The transformers get heated due to iron and copper losses occurring in them. It is necessary to dissipate this heat so that the temperature of the winding is kept below the value at which the insulation begins to deteriorate.
Another type of cooling provided for transformers is by means of external associated auxiliary equipment such as heat exchangers, radiators, or the like.

In the case of a radiator, pipes connect the transformer to an adjacently located radiator. These pipes conduct oil from the transformer to the radiator, where they are cooled, and back again to the transformer.
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The radiator may include pipe windings and heat exchange principles to regulate the temperature of oil from its relatively heated state to its relatively optimum working temperature.
For the facilitation of oil from the transformer to the radiator, either a suction pump is used or a delivery pump is used. In the case of use of a suction pump, the transformer oil is suctioned out from the transformer and relayed to the radiator by the pump. From the radiator the oil is naturally delivered to the transformer without use of a pump. Similarly, in the case of a delivery pump, the pump facilitates a delivery force, thus inducing a naturally occurring suction force at another end without the use of another pump.
The pipes may have a series of bends. With each bend, major losses increase due to
plausible occurrence of turbulence in the oil flow. Also, it is noted that since
pressure at either end of a pump is substantially different, the velocity of oil at
respective ends is different, thus resulting in head loss. This further results in
higher chances of cavitation. Cavitation is the formation of gas bubbles of a
flowing liquid in region where the pressure of the liquid falls below its vapour
pressure. Cavitation means that cavities or bubbles are forming in the liquid that is
i being pumped. These cavities form at the low pressure or suction side of the pump,
causing several things to happen all at once, viz.:

a. The cavities or bubbles will collapse when they pass into the higher
regions of pressure, causing noise, vibration, and damage to many of the components.
b. There may be loss in capacity.
c. The pump can no longer build the same head (pressure).
d. The pump's efficiency drops.
Still further, losses called major losses and minor losses are induced in any fluid. In any real moving fluid, energy is dissipated due to friction, as well as turbulence, unless the flow is laminar. Head loss (hloss) is divided into two main categories, "major losses" (hmajor_loss) associated with energy loss per length of pipe, and "minor losses" (hminor_loss) associated with bends, fittings, valves, etc.
The major head loss for a single pipe or duct can be expressed as: hmajor_loss =λ (1 / dh) (v2 / 2 g)

where, hmajor_loss = head major loss (m, ft) λ= friction coefficient 1 = length of duct or pipe (m) dh = hydraulic diameter (m) v = flow velocity (m/s, ft/s). g = acceleration of gravity (Ws2, ft/s2)
The minor head loss can be expressed as: hminor_loss = ζ v2/ 2 g
where, hminor_loss = head minor loss (m, ft) ζ = minor loss coefficient

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Since the velocity - v - in equation in general is related to the pipe or duct where the component is located, the sum of the minor losses in a pipe or duct can be expressed as:
Σ hminor_losses = Σ ζ(v / 2 g)
Prior Art:
US2359174 discloses an electrical induction apparatus. There is no disclosure of reducing minor head loss and cavitation.
US2479373 discloses a Cooling system for electrical apparatus, A cooler is provided which, In the form illustrated, is shown as having an upper header and a lower header connected to the upper and lower parts, respectively, of the transformer casing above and below the barrier. Cooler elements are provided between the headers and through which the c6oling liquid flows downwardly as indicated by the arrows. A pump is provided for causing a forced circulation of the cooling liquid through the circuit including the cooling ducts of the apparatus and the cooling elements of the cooler.
There is no disclosure which discusses elimination of cavitation or head loss. There is a need for an improved mechanism.
Objects of the Invention:
An object of the invention is to provide an interconnection mechanism using pumps between a transformer and a cooling mechanism which eliminates cavitation.

An object of the invention is to provide an interconnection mechanism using pumps between a transformer and a cooling mechanism which eliminates minor head loss.
Summary of the Invention:
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According to this invention, there is provided an interconnecting pump mechanism between a transformer and radiator, said mechanism comprises:
- a first pump, with a first head rating based on pre-defined parameters and computations, adapted to work as a suction pump located between said transformer and said radiator; and
- a second pump, with a second head rating based on pre-defined parameters and computations, adapted to work as a delivery pump located between said transformer and said radiator.
Typically, said first pump with said first head rating is equal to said second pump with said second rating.
Typically, said first pump with said first head rating and said second pump with said second rating provide cumulative force for continuous oil flow.
Typically, said transformer is an oil cooled transformer.
Preferably, said transformer is a forced oil cooled transformer.
Typically, said first pump is placed serially in line with said second pump.

Typically, said first pump is placed serially in line with said second pump on opposite sides of said radiator.
Brief Description of the Accompanying Drawings:
The invention will now be described in relation to the accompanying drawings, in which:
Figure 1 illustrates a normal interconnection mechanism between a transformer and a radiator using a suction pump; and
Figure 2 illustrates a normal interconnection mechanism between a transformer and a radiator using a delivery pump.
Figure 3 illustrates a schematic of the interconnection mechanism between a transformer and a radiator using pumps.
Detailed Description of the Accompanying Drawings:
Figure 1 illustrates a normal interconnection mechanism between a transformer (T)
and a radiator (R) using a suction pump (SP); and
P1 refers to pressure on input side for suction pump.
P2 refers to pressure on output side for suction pump.
Here,P2>Pl.
Reference numeral P refers to pipes transferring oil between Transformer and
Radiator.

Figure 2 illustrates a normal interconnection mechanism between a transformer (T)
and a radiator (R) using a delivery pump (PDP).
P3 refers to pressure on input side for delivery pump.
P4 refers to pressure on output side for delivery pump.
Here,P4>P3.
In these arrangements and mechanisms, typically the differential pressure on either side of the pump is substantially high leading to cavitation and losses.
According to this invention, there is provided an interconnecting pump mechanism (100) between a transformer and radiator.
Figure 3 illustrates a schematic of the interconnection mechanism between a transformer (T) and a radiator (R) using pumps.
Typically, said transformer and said radiator are adjacently located.
In accordance with another embodiment of this invention, there is provided a first pump (P3) adapted to work as a suction pump located between said transformer and said radiator.
In accordance with yet another embodiment of this invention, there is provided a second pump (P4) adapted to work as a delivery pump located between said transformer and said radiator.

A pump is typically rated in terms of height of water it is expected to output. For the purposes of this specification, it is called rated head of the pump.
Typically, said suction pump is a top pump. Typically, said delivery pump is a bottom pump. In case of Top and Bottom Pumps, the net positive suction head for each pump is reduced leading to smaller difference in fluid pressure at entry and exit and hence reducing Cavitation.
Since both the Major and Minor losses are dependant on the square of the velocity hence reducing the fluid velocity at the delivery end of the pump drastically reduces the head losses when two pumps of half the discharge each are mounted at the top and bottom as shown in the figure 3 of the accompanying drawings.
Since pumps of lower head ratings are used, power consumption is also reduced.
For selecting a pump head rating, the following input parameters are considered:
1) pump discharge (litres/min)
2) pipe diameter (mm)
3) pipe length (m)
4) No. of 90° bends
Further oil properties in terms of the following is considered:
1) density (kg/mΛ3)
2) kinematic viscosity (cst)
Output in terms of the following is obtained using above inputs and properties:

1) fluid velocity
2) reynolds no.
3) friction factor
4) major head loss (pipe length)
5) resistance coeff (bends)
6) minor head loss (bends)
7) total loss( major + minor) (in mts)
The rating of the pumps achieved due to this calculation is less than half the rating of the previous pump. This contributes to the technical advancement of this invention.
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 interconnecting pump mechanism between a transformer and radiator, said
mechanism comprising:
- a first pump, with a first head rating based on pre-defined parameters and
computations, adapted to work as a suction pump located between said transformer and said radiator; and
- a second pump, with a second head rating based on pre-defined parameters and
computations, adapted to work as a delivery pump located between said transformer and said radiator.
2. A mechanism as claimed in claim 1 wherein, said first pump with said first head rating is equal to said second pump with said second rating.
3. A mechanism as claimed in claim 1 wherein, said first pump with said first head rating and said second pump with said second rating provide cumulative force for continuous oil flow.
4. A mechanism as claimed in claim 1 wherein, said transformer is an oil cooled transformer.
5. A mechanism as claimed in claim 1 wherein, said transformer is a forced oil cooled transformer.
6. A mechanism as claimed in claim 1 wherein, said first pump is placed serially in line with said second pump.

7. A mechanism as claimed in claim 1 wherein, said first pump is placed serially in line with said second pump on opposite sides of said radiator.