| 摘要 |
PURPOSE:To control precisely and automatically the content of gas to be controlled so as to be set up to a required value and to simplify the operation by determining the opening time of a solenoid valve automatically to supply gas in accordance with a deviation between the content of gas to be controlled and the set point at the time of detection. CONSTITUTION:A compression pump 2 is arranged close to a closed room 1 to pressurize air at the inside of the room 1 and the pressurized air is exhausted to the outside of the room 1 by a pressure-reducing valve 4. Oxygen from an oxygen bomb 7 is supplied to the room 1 through a solenoid valve 8 and a pipe 9. A partial pressure sensor 11 to detect oxygen density as an electric signal and a partial pressure sensor 12 to detect air pressure as an electric signal are fitted to the inside of the room 1 and outputs from the sensors 11, 12 are inputted to an control part 13. The control part 13 provided with a CPU, an RAM, an ROM, etc. sets up the control time intervals of the valves 4, 8 and the pump 2 while considering the detection delay of the sensors 11, 12 and oxygen diffusion time into the room 1, and determines the opening time of the valve 8 automatically in accordance with a deviation between oxygen content and the set point at the time of detection to automatically control the gas content to a required value. |
