| 摘要 |
A pair of pumps (PA, PB) are provided, each of which comprises a bellows arrangement having an inlet and an outlet, and a reciprocating drive device for a compression and expansion movement of the bellows arrangements, and a pair of on-off (open-shut) electromagnetic valves, one of each being disposed in the inlet side and the outlet side of the bellows arrangements, so that during the compression movement of the bellows arrangements the on-off electromagnetic valve in the inlet side is closed, whereas the on-off electromagnetic valve in the outlet side is opened, and during the expansion movement of the bellows arrangements the on-off electromagnetic valve in the inlet side is opened and the on-off electromagnetic valve in the outlet side is closed. The twin-pump arrangement carries out the dispensing movements alternately. The dispensing-side outlets of the pumps at their ends are in flow connection, via a directional valve, with a spray gun (coating gun) (G). If the spray gun is not actuated during a certain period, the directional valve (3) is actuated, so that the fluid flow discharged by the pumps can be recirculated. <IMAGE>
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