| 摘要 |
<p>The invention relates to a security pneumatic control apparatus comprising an OR cell, an AND cell, a capacitor, connected to the OR cell by means of a debit regulator, and a priority cell connected to the capacitor and to the AND cell. The AND cell comprises a valve member, for engaging two seats, and a diaphragm, for moving the valve member onto one of the two seats. The cross-sections of the diaphragm and of the last mentioned seat of the AND cell are S'3 and S'2 respectively. The priority cell comprises a valve member, for engaging two seats, and a diaphragm, for moving the valve member onto one of the two seats. The cross-sections of the diaphragm and of the last mentioned seat of the prioritary cell are S3 and S1 respectively. In the invention, S'3/S'2<S3/S1. When the supply pressures at the OR cell and AND cell are not equal, the security remains guaranteed for the control of dangerous machines.</p> |
