| 摘要 |
The invention relates to a control device for alternate action on a hollow body with excess pressure, with atmospheric pressure and with reduced pressure of a medium. The sinusoidal functional path achievable with this control device is equivalent to a breathing effect. According to the invention, the control device consists of a unit which comprises a fan, one or more pressure control elements, one or more suction control elements and a switching pulse distributor. These assemblies are arranged, as regards their control function, such that the excess pressure which can be produced by means of the fan (pressure side) and also the reduced pressure which can be simultaneously produced (suction side) can alternately act on a hollow body, the respective control functions being changed over by a switch pulse distributor. The control function proceeds as follows: the fan, when the direction of rotation of the rotor remains the same, simultaneously produces a pressure on its pressure side and a reduced pressure on its suction side. These pressures are controlled by means of the abovementioned pressure and suction control elements and the switching pulse distributor such that there results an alternating action on the hollow body by pressure, atmospheric pressure and reduced pressure. Since this function has a sinusoidal path, the action on the hollow body with atmospheric pressure occurs automatically, in fact at the point of inflection of the sine curve in the region of the abscissa. Possibilities of application of the above-described system arise, e.g., in the production of flotation motions in mineral dressing machines, in the ventilation of flexible hollow bodies which are to expand and contract rhythmically, etc. <IMAGE>
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