| 摘要 |
A pump for viscous substances comprises a pump chamber (5) with an inlet (10), intended for connection to a source of the substance to be pumped, and an outlet (12), equipped with a valve, for pumping out the substance sucked into the pump chamber during an intake phase. The pumping action is achieved by varying the volume of the pump chamber. A unit (8) is arranged to control the variation of the volume of the pump chamber, such that the delivery phase is considerably shorter than the intake phase. The inlet is further devised such that it presents a greater resistance to flow than the outlet when the outlet valve (14) is open, so the backflow of substance through the inlet during the delivery phase only corresponds to a minor portion of the stroke volume of the pump. <IMAGE> |
