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
A system and method for cleaning vacuum interrupter contacts.
APPLICANTS:
Crompton Greaves Limited, CG House, Dr. Annie Besant Road, Worli, Mumbai -400030, Maharashtra, India, an Indian Company
INVENTOR
Chaudhari Sushil Ekanath of Crompton Greaves Ltd, High Voltage Product Technology Centre, CG Global R&D Centre, Kanjurmarg (E), Mumbai - 400 042, Maharashtra, 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 electrical equipment and control systems.
Particularly, this invention relates to the field of vacuum interrupter contacts.
Specifically, this invention relates to a system and method for cleaning vacuum interrupter contacts.
BACKGROUND OF THE INVENTION:
Vacuum interrupters are a type of switchgear equipment which finds its use in power network operators and power switching technology. Vacuum interrupters include a set of contacts (fixed as well as movable) which connect or disconnect in accordance with the working parameters to enable or disable switching, accordingly.
There can be minute defects on the surface of the vacuum contacts. These defects are not visible but are required to be removed. To remove these defects, generally twice the voltage is applied on the surface to make it smooth.
If high voltage is applied under the oil, then there will be problem of oil removal from the surface and spillage. A typical solvent namely tri-chloro ethylene is required to degrease the oil.
To remove the surface defects from the vacuum interrupter's (VI) surface, High Voltage (HV) is applied in between the electrodes under the transformer oil. This

leads to more time to remove the oil from VI's surface, which leads to additional
energy requirement.
Hence, it is important that the contacts be cleaned, in an efficient manner, to ensure a smooth and longer life of the vacuum interrupter.
Objects of the Invention:
An object of the invention is to remove surface defects from vacuum contact's surface.
Another object of the invention is to remove surface defects from vacuum contact's surface under gases.
Still another object of the invention is to provide a system which removes surface defects from vacuum contact's surface which system saves the cost as well as time.
An additional object of the invention is to provide a system which removes surface defects from vacuum contact's surface which system is operated by a control system.
Yet an additional object of the invention is to provide a system which removes surface defects from vacuum contact's surface which system eliminates additional energy requirement.

SUMMARY OF THE INVENTION:
According to this invention, there is provided a system for cleaning vacuum interrupter contacts, said system comprises:
a. a fabricated chamber comprising at least an electrode attached to a high
voltage source and other electrode attached to ground and adapted to receive
at least one vacuum interrupter contact;
b. at least a first gas reservoir adapted to be connected to said fabricated
chamber by means of at least a first pump in order to pump in gas to said
chamber;
c. at least a second gas reservoir adapted to be connected to said fabricated
chamber by means of at least a second pump in order to pump out gas from
said chamber; and
d. at least a first vacuum pump adapted to create a vacuum in said fabricated
chamber.
Typically, said fabricated chamber comprising at least an electrode attached to a high voltage source adapted to receive a plurality of vacuum interrupter contacts.
Typically, said gas reservoir is filled with a gas selected from a group of gases consisting of Nitrogen, SF6, and SF6 + N2 gas mixture.
Typically, said first pump being an inline pump is actuated by means of a first solenoid valve such that said fabricated chamber is tested for leakage by vacuum or positive pressure test to take the gas inside said chamber.
Typically, said second pump being an inline pump is actuated by means of a second solenoid valve to pump out the gas from the chamber to the reservoir after the process.

Typically, said system comprises a gas cylinder adapted to provide gas to said first gas reservoir.
Typically, said vacuum pump is connected to a third solenoid valve to evacuate said fabricated chamber.
Typically, said system comprises a moisture trap at each of said first and second gas reservoirs and in the main chamber.
Typically, said chamber comprises a glass window.
Typically, said chamber comprises a pressure monitoring system and pressure relief device adapted to measure and monitor pressure of input gas in said chamber for safety purpose.
According to this invention, there is also provided a method for cleaning vacuum interrupter contacts, using a system, said method comprises the steps of: i. provisioning leakage testing of a closed fabricated chamber containing with or without at least two electrodes and at least one vacuum interrupter contact by vacuum using a vacuum pump or positive pressure of N2 gas; ii. pumping in the gas to said chamber from a first reservoir using a first pump; iii. maintaining and monitoring required pressure of said gas though a pressure
measuring device; iv. applying high voltage between said electrodes for removing defects from the
surface of said vacuum interrupter contacts; v. pumping out gas from said chamber to a second reservoir using a second
pump; and vi. removing vacuum interrupter contacts from said chamber.

Typically, said method comprises the step of provisioning leakage testing of a closed fabricated chamber containing a plurality of electrodes and a plurality of vacuum interrupters contact by vacuum using a vacuum pump or positive pressure
ofN2gas.
Typically, said method comprises the step of activating a second solenoid valve for outputting gas, to said second reservoir, from said chamber while deactivating a first solenoid valve for restricting input of gas, from said first reservoir, into said chamber.
Typically, said method comprises the step of activating a first solenoid valve for inputting gas, from said first reservoir, into said chamber while deactivating a second solenoid valve for restricting output of gas, into said second reservoir, from said chamber.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The invention will now be described in relation to the accompanying drawings, in which:
Figure 1 illustrates a schematic of the system; and
Figure 2 illustrates a fabricated chamber for keeping vacuum interrupter contacts for cleaning purposes.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
According to this invention, there is provided a system for cleaning vacuum interrupter contacts.
There can be minute defects on the surface of the vacuum interrupter contacts. These defects are not visible but are required to be removed. To remove these defects, generally twice the voltage is applied on the surface to make it smooth.
Figure 1 illustrates a schematic of the system of this invention.
In accordance with an embodiment of this invention, the system (100) comprises a fabricated chamber (200) (Figure 2 of the accompanying drawings). This chamber is attached to a high voltage source. The chamber is mounted with a solenoid valve, and it is attached to a gas reservoir. Typically, the gas reservoir is filled with Nitrogen and or SF6and or mixture of both gases. At least one vacuum interrupter contact (12) is placed in the chamber and vacuum is created by applying vacuum in the chamber using vacuum pump to evacuate the chamber and checking the leakage in the chamber. There may a plurality of vacuum interrupter contacts which may be placed in the chamber. The chamber includes electrodes which provide high voltage between them. Then, the gas and or gas mixture is pumped into the chamber from the reservoir and the high voltage is applied. After the processing, the gas is pumped back to reservoir. The batch is ready for packaging.
In accordance with an embodiment of this invention, the system (100) comprises at least a first gas reservoir (14) adapted to be connected to the fabricated chamber (200) by means of at least a first pump (16). The at least a first pump is adapted to pump in gas to the chamber. The pump is actuated by means of a first solenoid

valve. Typically, the gas is SF6, nitrogen, and / or SF6 + N2 gas mixture. This will leads to clean operation, less energy consumption, and freedom from recycling of solvent issues.
In accordance with another embodiment of this invention, the system comprises at least a second gas reservoir (18) adapted to be connected to the fabricated chamber (200) by means of at least a second pump (20). The at least a second pump is adapted to pump out gas to the gas reservoir or to pump out gas from the chamber. The pump is actuated by means of a second solenoid valve. Typically, the gas is SF6, nitrogen, and / or SF6 + N2 gas mixture. When the second solenoid valve is activated, the first solenoid valve is in deactivated state. When the first solenoid valve is activated, the second solenoid valve is in deactivated state. This ensures that the gas is either filled into the chamber or is pumped out of the chamber without losses.
In accordance with yet another embodiment of this invention, the system comprises at least a first vacuum pump (22) to create a vacuum in the fabricated chamber (200). The vacuum pump is operated by means of a third solenoid valve.
In accordance with still another embodiment of this invention, the system comprises a gas cylinder (24) adapted to provide gas to the first gas reservoir (14).
The system comprises a moisture trap (26) at each of the gas reservoirs (14, 18) and on main chamber (200) to remove the moisture present or ingress in the gas.
The chamber (100), of the system of this invention, comprises a glass window (28) and a pressure monitoring system (30) to measure and monitor pressure of input gas in the chamber (200).

According to this invention, there is provided a method for surface treating of vacuum interrupter contacts, using the system (100).
The chamber is mounted with a pressure relief device (29) for safety purpose. The first gas reservoir (14) and second reservoir (18) are interconnected to exchange the gas.
The method comprises the following steps:
1. First leakage of the chamber (100) is done by vacuum or positive pressure of N2 gas by means of vacuum pump (22).
2. Vacuum interrupter contacts are kept in High Voltage seasoning chamber (200) and the chamber is closed. The desiccants are absorbing the moisture present in gas.
3. The gas or gas mixture is pumped in the chamber (200) through the first
reservoir (14) using pumping system. The required pressure of the gas is
maintained and monitored though the pressure measuring device (30). After
certain pressure of the gas, the solenoid valve on the first pump (16) is shut and
the vacuum interrupter contacts are under the pressure of gas or gas mixture.
4. The high voltage is applied between the electrodes for removing the defects from the surface of the vacuum interrupter contacts.
5. After this operation, the gas is pumped by means of a second pump (20) to second reservoir (18) through the pumping system and this time the solenoid valve of first pump (16) is shut along with the interconnecting line of gas.
6. After ensuring that the entire gas is locked in the second reservoir (18), the surface finished vacuum interrupter contacts are taken out from the chamber (200).

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. A system for cleaning vacuum interrupter contacts, said system comprising:
a. a fabricated chamber comprising at least an electrode attached to a high
voltage source and other electrode attached to ground and adapted to
receive at least one vacuum interrupter contact;
b. at least a first gas reservoir adapted to be connected to said fabricated
chamber by means of at least a first pump in order to pump in the gas to
said chamber;
c. at least a second gas reservoir adapted to be connected to said fabricated
chamber by means of at least a second pump in order to pump out the gas
from said chamber; and
d. at least a first vacuum pump adapted to create a vacuum in said fabricated
chamber.
2. A system as claimed in claim 1 wherein, said fabricated chamber comprising at least an electrode attached to a high voltage source adapted to receive a plurality of vacuum interrupter contacts.
3. A system as claimed in claim 1 wherein, said gas reservoir is filled with a gas selected from a group of gases consisting of Nitrogen, SF$, and SFg + N2 gas mixture.
4. A system as claimed in claim 1 wherein, said first pump being an inline pump is actuated by means of a first solenoid valve such that said fabricated chamber is tested for leakage by vacuum or positive pressure test to take the gas inside said chamber.

5. A system as claimed in claim 1 wherein, said second pump being an inline pump is actuated by means of a second solenoid valve to pump out the gas from the chamber to the reservoir after the process.
6. A system as claimed in claim 1 wherein, the said system comprises a gas cylinder adapted to provide gas to said first gas reservoir.
7. A system as claimed in claim 1 wherein, said vacuum pump is connected to a third solenoid valve to evacuate the said fabricated chamber.
8. A system as claimed in claim 1 wherein, the said system comprises a moisture trap at each of said first, second gas reservoirs and on the chamber.
9. A system as claimed in claim 1 wherein, said chamber comprises a glass window.
10. A system as claimed in claim 1 wherein, said chamber comprises a pressure monitoring system and pressure relief device adapted to measure and monitor pressure of input gas in said chamber for safety purpose.
11. A method for surface treating of vacuum interrupter contacts, using a system, said method comprising the steps of:
i. provisioning leakage testing of a closed fabricated chamber containing with or without at least two electrodes and at least one vacuum interrupter contact by vacuum using a vacuum pump or positive pressure of N2 gas; ii. pumping in the gas to said chamber from a first reservoir using a first inline pump;

iii. maintaining and monitoring required pressure of said gas though a pressure
measuring device; iv. applying high voltage between said electrodes for removing defects from the
surface of said vacuum interrupter contacts; v. pumping out gas from said chamber to a second reservoir using a second
pump; and vi. removing vacuum interrupter contacts from said chamber.
12. A method as claimed in claim 1 wherein, said method comprises the step of provisioning leakage testing of a closed fabricated chamber containing a plurality of electrodes and a plurality of vacuum interrupters contact by vacuum using a vacuum pump or positive pressure of N2 gas.
13. A method as claimed in claim 1 wherein, said method comprises the step of activating a second solenoid valve for outputting gas, to said second reservoir, from said chamber while deactivating a first solenoid valve for restricting input of gas, from said first reservoir, into said chamber.
14. A method as claimed in claim 1 wherein, said method comprises the step of activating a first solenoid valve for inputting gas, from said first reservoir, into said chamber while deactivating a second solenoid valve for restricting output of gas, into said second reservoir, from said chamber.