摘要 |
<p>The supply of a pressure fluid to one or more outlets (17,18) additional to a permanent outlet (16) is controlled by the provision for the or each additional outlet of a pressure fluid circuit including sources (4,5) of higher and lower reference pressure fluids and three comparator valves (10;100, 20;200, 30;300) using the reference pressure fluids and the pressure fluid to connect the pressure fluid to the additional outlet when the pressure fluid pressure exceeds the higher reference pressure and to disconnect the pressure fluid from the additional outlet when the pressure fluid pressure falls below the lower reference pressure.</p> |