| 摘要 |
<p>1,176,895. Roof ventilators. BIG DUTCHMAN (NEDERLAND) N.V. 24 April, 1968 [26 April, 1967], No. 19254/68. Heading F4V. A ventilator for an animal house comprises inner and outer tubes 2, 3 for discharging and supplying air respectively, four transverse ducts 5, an extension 14 housing a fan and extending to the lower part of the house and four valves 9 movable to permit fresh air to be drawn in to replace exhausted air or movable to cause recirculation of the air in the house. The portion of the valves extending into the inner tube 2 may be triangular so that the four valves together substantially close the tubes. A cable 12 connects the valves to a step-by-step motor 10 coupled to a winch 11. Coil springs or counterweights ensure that the cables remain taut. The motor is energized by current pulses provided by a temperature regulator. The valves could be manually operated. Extensions 16 may be fitted to the ducts 5 and may carry adjustable baffles 18. Baffles 18 could be positioned in ducts 5.</p> |
