| 摘要 |
<p>A valve which allows a small quantity of a tracer fluid to be injected into a stream of carrier fluid and comprising a valve body (1) and an electrically controlled (5) shutter (3) interacting with a closure seat (8) to control the entry flow rate of the tracer fluid. The shutter (3) is situated in the middle of a mixing chamber (12) and the carrier fluid continually passes through this chamber perpendicularly to the direction of movement of the said shutter, thus sweeping the whole periphery of its seat (8). Such a valve can be used, for example, in the simulation of air polluted by a specific contamination. The degree of contamination can be modified even during the tests by means of the electrical control. <IMAGE></p> |
