| 摘要 |
For prefilling a pump chamber of a cyclically operable dosing or atomising pump of a container filled with filling material and closed by the pump, it has already been proposed to open an outlet valve by means of a pump pressure stroke and to bring into effect, through the open outlet valve, a subatmospheric pressure which conveys filling material into the pump chamber, before, via a subsequent suction stroke, the pump chamber is more extensively filled. In particular in the case of gel-like filling material, this is expedient in order that, for discharging a dosed filling material quantity, a series of pump strokes does not first have to be carried out, but the pump delivers already during the first pump pressure stroke. In the method proposed, the subatmospheric pressure is controlled temporally in such a manner that it is already reduced before the outlet valve of the pump is closed. The result of this is either an incomplete prefilling of the pump chamber or too strong a filling, that is to say an overflowing of the filling material via the outlet valve. According to the invention, these disadvantages are eliminated by the action of the subatmospheric pressure in the pump chamber being ended only by the closing of the outlet valve and the subatmospheric pressure being maintained beyond the closing of the outlet valve at least over a part of the suction stroke of the pump.
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