| 摘要 |
PCT No. PCT/EP97/03011 Sec. 371 Date Dec. 7, 1998 Sec. 102(e) Date Dec. 7, 1998 PCT Filed Jun. 10, 1997 PCT Pub. No. WO97/47182 PCT Pub. Date Dec. 18, 1997A duct made of flexible material, comprising a plurality of spaced dispensers and regulator valves. Each dispenser is provided with two ports, one for ground dispensing and the other one for over-the-crop dispensing; the ports are controlled by respective differential membrane valves. The ports are supplied by separate system sections, one at low pressure and the other one at high pressure, which comprise respective pipes which are supplied by corresponding motorized pump units at low and high pressure respectively; the pipes are joined in a single duct with side-by-side passages provided with a cross-section shaped substantially like a figure-of-eight.
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