| 摘要 |
PURPOSE:To obtain higher efficiency in pump delivery and its thermal insulation by introducing a fluid in a pump casing having the leading side of a vane, into the concave part of a rotor via a connecting passage. CONSTITUTION:A fluid in a pump casing 8 having the leading side of a vane 2 is made to flow into the concave part 4 of a female rotor 3 via a connecting passage 14, an open-close groove 15 formed at the side of a male rotor 1 and another connecting passage 16, from the neighborhood where compression stroke starts with the contraction of the casing volume. Consequently, as the pump casing 8 is depressurized and a relief groove can be eliminated, it has become possible to make larger the pump delivery capacity and improve the pump delivery efficiency. Also, a fluid in the said concave part 4 is pressurized by the inflow of a liquid from the pump casing 8, and the thermal insulation efficiency of the pump is improved.
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