| 摘要 |
<p>A fluid metering device mixes a predetermined quantity of a first fluid with a larger quantity of second fluid supplied to the device at a higher pressure on each cycle. The pressure of the second fluid provides the force necessary to motivate a first pumping means which on movement to an 'outlet' position within a housing displaces the mixed fluids on an outlet side of the first pumping means to their destination. Movement of the first pumping means actuates a second pumping means which pumps a predetermined quantity of the first fluid into the housing on each cycle. On the maximum pumping stroke of the first pumping means being reached at the 'outlet' position, a passage is opened in the first pumping means which is then restored to an 'inlet' position, the second fluid in the housing passing through the passage during such restoration and thus being available for despatch on the next pumping stroke. When the first pumping means reaches the 'inlet' position the passage closes and a further pumping cycle commences.</p> |
