| 摘要 |
<p>The appts. pneumatically incorporates >=1 shutter mounted in a clearing-aie duct between the clearing-air gas fan and the filter. The shutter and the duct are arranged so that the shutter can turn about an off-centre axis between a closed and an open position under the action of a controller. In the closed position the resultant of the upstream forces tend to open the shutter. In the open position, the shutter presents a profile in the gas stream. The extent of the opening can be regulated by an adjustable stop. The controllers are pneumatic jacks. The duct has a square or rectangular section. There are pref. two shutters symmetrically placed w.r.t. a median plane of the duct. Each has cross-section with a leading edge and a trailing edge in the open position. The pivoting axis is near the leading edge, at the centre of press in the closed position. The appts. gives a pulsed flow which can be controlled to give the most effective sequence of pulsations. It allows the time of opening of the shutter to be reduced so as to give the effect of a press. wave. It occupies no space and causes very small press. drops in the gas flow. It can be regulated to give different openings giving different intensities of the press. wave for different cleaning duties. It is simple to construct and reliable in action.</p> |
