摘要 |
<p>1. Control device for a pressure-medium controlled valve (2) arranged in a supply line (1), the control pressure medium connection for actuating the valve being connected by way of a control line (4, 19) to a control pressure source (18) of a control circuit that is separate from the supply line, especially of a control circuit having a pressure that is lower than the pressure in the supply line (1), characterised by the following features : a) in the control line there is arranged a shut-off valve (14, 16, 24) which is open during normal operation and which has a pressure-medium inlet (17) and a pressure-medium outlet (5) for the control pressure ; b) the pressure-medium inlet (17) is connected to the pressure-medium outlet (5) by way of the shut-off valve (14, 16, 24) and a throttle (10), c) parallel to the throttle (10) is arranged a differential pressure measuring device (12, 9, 7, 27) which controls the actuation of the shut-off valve (14, 16, 24) ; d) the differential pressure measuring device (12, 9, 7, 27) is so constructed that the shut-off valve (14, 16, 24) is closed when the pressure supplied to the differential pressure measuring device (12, 9, 7, 27) from the pressure medium outlet (5) is greater than the pressure supplied to the differential pressure measuring device (12, 9, 7, 27) from the other side of the throttle (10).</p> |