| 摘要 |
<p>Valve 11 includes a slide sliding in a first chamber 26 with the possibility of reaching two stable end positions opposite each other. In the first position the slide 21 allows intercommunication between a conduit 6 for supply of the product from a supply source and conduit 12 communicating with the upper part of chamber 10 of a double acting piston 9, as well as the intercommunication of the other part of chamber 10 with a conduit 15 connected to a delivery apparatus; in the second position the slide allows the reversal of such connections. To avoid the infiltration and mixing of the fluid under pressure used for the control of valve 11 in the conduits in which the product circulates, said slide 21 is equipped with a projection 35 which extends beyond one of the ends of the chamber 26 and is connected to a small pneumatically controlled piston 36, sliding in a second chamber 37, separate from the first.</p> |
