| 摘要 |
A selected range arc settable spray nozzle with pre-set table precipitation rate in which the arc of coverage adjustment is coupled to an upstream flow throttling valve. As the arc of coverage is adjusted, the opening of the upstream flow throttling valve is proportionally adjusted to maintain the precipitation rate substantially constant independent of arc of coverage adjustments. Upstream flow throttling achieved by use of pre-selected number of larger slots for desired flow whose opening area is varied as the arc is being set. The precipitation rate is set by adjusting the throttling valve to provide the desired flow rate for the maximum arc of coverage setting. A pressure compensating valve may also be provided.
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