INTRODUCTION
Atmospheric pressure and oxygen content starts reducing gradually with altitude. To assist pilots to fly Military or trainer aircraft like IJT at very high altitude, have Oxygen cylinders to supply oxygen to Pilots. It is major part of Life Support System of any aircraft. Aircraft Oxygen Cylinders are to be charged to desired value prior to next sortie. A fully charged commercial oxygen cylinder can charge only twice, till its pressure settles down equal to aircraft cylinder pressure. The commercial cylinders have to be discard with approximately 80 bar pressure remaining. Alternatively, these commercial cylinders may be utilized further for charging aircraft cylinders with a booster arrangement.
BACKGROUND OF THE INVENTION
There are 3 oxygen cylinders in IJT aircraft. All cylinders are interconnected & operates simultaneously. During flight, system is operated in 2 modes. One is in "Normal Mode", when oxygen is supplied to pilot with appropriate mixing of air. Second is "Emergency Mode", when pure oxygen is supplied to pilot. Each cylinder has volume of 511 Cu-ln and maximum charging pressure of 130 bar. Consumption of oxygen for 1 hr sortie with 2 pilots reduces cylinder pressure from 130 bar to 90 bar. These cylinders needs to be recharged to 130 bar, prior to next sortie. A fully charged commercial oxygen cylinder can charge only twice, till its pressure settles down equal to aircraft cylinder pressure. The commercial cylinders have to discard with approximately 80 bar pressure remaining. Alternatively, these commercial cylinders may be utilized further for charging aircraft cylinders with a booster arrangement.

DETAILED DESCRIPTION OF THE INVENTION
Present disclosure of Oxygen Charging Trolley is about an equipment for in-situ charging of oxygen cylinders of IJT aircraft with the help of its booster. Booster of the Trolley functions either with line air supply available in hangers or it can also function stand alone with the pressure from Nitrogen Cylinder mounted on the Trolley. The compact Trolley saves considerable time & energy.
For understanding of this disclosure & its features, reference is now made to following description taken in conjunction with the accompanied figures: Figure 1: Circuit Diagram of Oxygen Charging Trolley. Figure 2: Oxygen charging trolley.
Present disclosure is about Oxygen charging trolley of IJT, its elements & use. Please take all figures into consideration for understanding.
Oxygen Charging Trolley consists of item 1 to 11. It uses two cylinders one for Oxygen 11 another for Air/Nitrogen 10. Item 10 use is optional we can connect normal compressor air as drive air to be connected through Drive Air On/Off valve 4. Use of item 10 has extra advantage in a place where we do not have compressor supply like tarmac. Out put of drive air cylinder 10 is connected to pressure regulator 1 via SS braided connecting hose 9. Since we are dealing with oxygen that too high pressure utmost care has been taken to select the parts. All items are oxygen vetted & pressure tested. Item 1 is connected to Filter regulator unit 2. Output of item 2 is connected to Drive air pressure gauge 3. Drive line is further connected to item 4. As described earlier it is used to connect compressor air if so required. Drive further goes to booster pump 5. Item 5 has another input as described further.
Item 11 is commercial oxygen cylinder. Output of item11 goes to regulator 1
through SS braided hose 9. Item 1 is further connected to inlet pressure gauge 6. Now
oxygen goes to item 5. Now after boosting the oxygen booster pump 5 supplies it to output
point which is aircraft oxygen cylinder through SS braided hose 9. To control the output
pressure gauge 7 is also provided: Out put is also fitted with safety relief valve 8 which
fails at a pre determined pressure. In our case it is 200 bar. ^

CLAIMS :
We claimed that the -
1. Design and Development of Drawing of "Oxygen Charging Trolley for IJT aircraft" has been done by IJT-LSP, HAL.
2. Fabrication of "Oxygen Charging Trolley for IJT aircraft" has been done by IJT-LSP, HAL.
3. Oxygen Charging Trolley for IJT aircraft has been a success and being used for charging oxygen cylinders of IJT aircraft.