| 摘要 |
PURPOSE: A vacuum pressure control device is provided to reduce the dropping rate of pressure and to reduce undershoot. CONSTITUTION: A vacuum pressure control device(8) comprises a vacuum proportional on/off valve, a pressure sensor(17), and a controller(56). The vacuum proportional on/off valve comprises a valve body and an air cylinder. The pressure sensor measures the vacuum pressure in a vacuum container. The controller controls the pressure of the vacuum container. When the measured pressure in the vacuum container is dropped over a constant pressure dropping rate, the internal pressure of the air cylinder is exhausted.
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