| 摘要 |
PURPOSE:To prevent vapor lock in a car fuel pump, in which a regenerative pump impeller is incorporated, by installing a small dia. pump at the fore stage of said regenerative pump coaxially, thereby bleeding the vapor, and applying a pre-pressure. CONSTITUTION:A centrifugal pump 50 is installed at the fore stage of a regenerative pump 34 coaxially, and a vapor exhaust passage 48 to put the vapor exhaust hole 46 in communication with a cross hole 60, bored in the external cylinder 12, is formed at a point nearer the center than a discharge port 44, viewed in the radial direction. The centrifugal pump 50 separates the vapor from liquid, and the vapor is concentrated at the center of the centrifugal pump to come into a recess 30, situated over, after passing through the above-mentioned vapor exhaust hole 46, and further is exhausted to outside the pump via vapor exhaust passage 48 and cross hole 60. Accordingly the pre-pressured fuel bled with vapor flows into a regenerative pump to constitute a second stage pump, so that there is no fear of generation of vapor lock phenomenon.
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