| 摘要 |
PURPOSE:To enable to control the pneumatic pressure of the air supply source at a constant pressure, by detecting the movement of a pointer of a pressure gauge monitoring the variation of air pressure, converting it into an electric signal, and controlling the number of revolutions of motor for the pneumatic pump. CONSTITUTION:When air supply pumps 1, 2 are operated, the pneumatic pressure of a pneumatic vessel 3 increases, a pointer 40 of a pressure gauge 4 passes through the point P, the light from a photocoupler 5 is interrupted and the output voltage from a phototransistor 53 is decreased, thereby lowering the driving voltage of the motor 1 and reducing the air supply amount of the air supply pumps 1, 2. When the air supply amount of the air supply pumps 1, 2 is decreased, the pointer 40 is decreased from the point P and operation is made inversely from the above- mentioned operation and the output voltage of the phototransistor 53 is increased, allowing to increase the air supply amount of the air supply pumps 1, 2 and to control the pneumatic pressure of the pneumatic vessel 3 to a constant value. |
