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 exhaust machine control system
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worii, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTORS
Bagul Nilesh Ramkrishna, Vellore Pachiappa Baburajan, both of Crompton Greaves Ltd, Village Kural, Padra Jambusar Road, Vadodara. Gujarat, both, Indian Nationals.
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 an exhaust machine control system. Particularly, the present invention relates to an exhaust machine control system used in the production of electric lamps, particularly, fluorescent lamps.
BACKGROUND OF THE INVENTION
Production of electric lamps such as fluorescent lamps undergoes various processes such as washing, phosphor coating, mount making, sealing, exhausting, basing, aging and inspection. One of the processes to produce the fluorescent lamps includes the process of exhausting. The exhaust machine includes a drive means which is constituted by a motor and a gear mechanism. The drive means rotates the machine at a constant speed in an anticlockwise direction. On the machine, there are in total 40 heads. The machine rotates in a double index mode. Each of these heads holds a lamp which has been conveyed from the sealing machine by the conveyor. While the lamp is held by the head, an air-tight state is secured between the lamp and the head. Under this condition, air is exhausted from the lamp by a vacuum pump connected to the head, and then mercury and inert gas are introduced into the lamp. After the lamps have undergone the exhausting process, only the good ones with their exhaust tubes sealed are shifted to the conveyor means and are carried to the capping machine.
The exhaust machine is also provided with limit switches on a shaft which rotates with the machine. Different metal cams are mounted on the shaft. When the cam is disposed near the limit switch position, the limit switch lever gets pressed and is turned

on, and then produces an output signal. The output signal of the limit switch is transferred to a controller. The limit switch supplies a signal to the controller when each head passes by it. Further, a vacuum gauge is provided to detect the vacuum in each bulb member held by the respective head. The vacuum detector automatically detects the vacuum in each bulb member as the bulb member passes by position. If the vacuum in the bulb member is found to fall outside a predetermined range of allowance, the vacuum detector delivers an output signal. This output signal is supplied to the controller.
The operation also provides a reject mechanism. When the head, which is holding a bulb member, which is found to be an abnormal vacuum condition, passes the position, the reject mechanism i.e. leak detector cylinder operates and it closes the particular head, which forcibly removes the above mentioned abnormal bulb member from the head. The leak detector cylinder operating timing is given by the cam sensor.
In the exhausting machine, a total of two leak detector systems are used which includes a totalof four cylinders, as the machine is double index.
In the existing systems which were used for exhaust machine operation, mechanical operated limit switches were deployed. The aforesaid limit switches got operated only when the physical contact of metal cam with limit switch lever occurred and therefore there was a malfunction in the system, due to which stoppage of machine was occurring. Further, the downtime of the machine for 1 year was about 325 min. Troubleshooting of the problem was also consuming a lot more time.

OBJECTIVES OF THE INVENTION
An objective of the invention is to obviate the aforesaid drawbacks by providing an exhaust machine control system to simplify the troubleshooting of the machine failure.
DETAILED DESCRIPTION OF THE INVENTION
In order to achieve the aforesaid and other objectives, according to the invention, an exhaust machine control system used in an apparatus for manufacturing electric lamps is disclosed, which comprises of a cam. plurality of inductive proximity sensors connected to the cam, and a relay control system connected between the proximity sensors and the field devices like solenoid coil, mercury coil, etc.
These and other aspects, features and advantages of the invention will be better understood with reference to the following detailed description, accompanying drawings and appended claims, in which,
Fig 1 illustrates a cross section of the exhaust machine control system according to the present invention.
According to the invention, an exhaust machine control system used in an apparatus for manufacturing electric lamps is disclosed, which comprises of a cam (C), plurality of inductive proximity sensors (S1, S2, S3, S4, S5, S6) connected to the cam (C), and a relay control system (RC) connected between the proximity sensors and the

field devices like solenoid coil, mercury coil, etc (The field devices are not shown in the figure 1). When these electric lamps are tested for operation, said inductive proximity sensors operate and activate the relay control system, if vacuum in said electric lamps exceed a predetermined value.
The relay control system operates on a 24V dc supply, which acts as an isolator between the sensors and the above stated field devices. The inductive proximity sensors include an indicator, like a red light to indicate that the said sensor is working. These inductive proximity sensors (S1 to S6) are connected to the system using nuts and bolts N1 to N6 respectively.
A preferred embodiment has been explained hereinafter in which the proximity sensor S1 is used for the leak detector cylinder LD1 being connected to wire no 7. The LD1 operates if vacuum is more than the manometer set point. Therefore, if the proximity sensor S1 operates, it operates the 24 V dc relay and, if at that time, the vacuum in line is more than the predetermined set point, and then the LD1 cylinder operates to close the lamp head of the exhaust machine. On timing of leak detector (LD2) is added for the second leak detector operation and if at that time vacuum controller gives leak signal, the cylinder gets operated. The proximity sensor S2 is used for the operation of LDl vacuum solenoid valve, which is connected to wire no 8. The proximity sensor S3 is used for the operation of arching of the lamps, which is connected to wire no 9. Proximity sensor S4 is used for the mercury dozing coil operation for filling of mercury in lamp, which is connected to wire no 9. Proximity sensor S5 is used for safety timing, which means that if

this sensor is on and in the meanwhile, if any lamp head opener cylinder (out of the two cylinders) does not get back to its rest position, then the machine gets halted to avoid any accident. Proximity sensor S6 is used for the extra mercury dozing coil. Extra mercury dozing operates when the sensor gets actuated by the metal cam.
After the present invention was installed, there was zero downtime due to the use of the proximity sensor control mechanism, thereby implying that there was no failure of the system.
Advantages:
1. Exhaust machine downtime has been reduced from 325 min to zero min.
2. Inductive proximity sensors are sensed by the metal cam, which then operates the 24 V dc relay, which gives isolation to sensors from the field devices like solenoid coil, mercury coil so avoids failure of sensors.
3. Further, indication lamp used for each individual input/ output simplifies the troubleshooting of machine failure.
Although the invention has been described with reference to a specific embodiment, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiment, as well as alternate embodiments of the invention, will become apparent to persons skilled in the art upon reference to the

description of the invention. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the invention as defined.

We claim:
1. An exhaust machine control system used in an apparatus for manufacturing electric lamps comprising of
a. a cam;
b. plurality of inductive proximity sensors connected to said cam; and
c. relay control system connected between said proximity sensors and known
field devices.
such that, when said electric lamps are tested for operation, said inductive proximity sensors operate and activate said relay control system, if vacuum in said electric lamps exceed a predetermined value.
2. An exhaust machine control system as claimed in Claim 1, wherein said relay control system operates on a 24V dc supply.
3. An exhaust machine control system as claimed in Claim 1, wherein said inductive proximity sensors include a light indicator.
4. An exhaust machine control system as claimed in Claim 1, wherein said relay provides an isolation to said sensors from said field devices.

5. An exhaust machine control system as claimed in any of the Claims 1 to 4, wherein said electric lamp includes a fluorescent lamp.