| 摘要 |
<p>The material (fertiliser, insecticide etc.) to be sprayed is sent to the spray nozzles by a pump driven from the tractors engine, whose speed does not bear a constant proportion to the tractors ground speed. The regulator corrects the disproportion. It accepts the pump output and delivers the right quantity to its exit (4), returning the rest to the reservoir via a pressure equalizing valve (31, 3). The regulator uses a slipping clutch (5) driven (7, 8) from one of the tractors road wheels; this clutch turns a disc (10) as far as allowed by a spring (11) which is wrapped round the disc in a high-friction channel (12): this arrangement makes the angular displacement proportional to the ground speed. The turning disc moves an S-shaped blind (15, wrapped round 17 and 14) across the slit (between 14a and b) which is the outlet from the regulator to the exit pipe (4).</p> |
