| 摘要 |
<p>An apparatus is described for mixing a foam additive with water in a predetermined proportion for use in a foam-water fire fighting system (l6). The apparatus takes water from the fire main (ll) along a pipe (65) and uses this water pressure to work a piston-type motor and pump (70,l8) to develop an additive pressure slightly exceeding the water pressure in the fire main (l6). A weighted valve member (45) rises in response to increased flow from the main and correspondingly increases the flow area of an annular port (4l) through which the additive flows from the pump (l8) into the water line (ll,30,l4,l5).</p> |
