| 摘要 |
PROBLEM TO BE SOLVED: To prevent polymerization and solidification of fluid reliably by providing, in a partition portion separating a pump portion and gas seal chamber, a communication hole for communicating a pump chamber in the pump portion and the gas seal chamber. SOLUTION: A communication hole 42 is pierced in a partition portion separating a gas seal chamber 12 and pump casing 14. Fluid is filled in a pump chamber 22 and flows into the gas seal chamber 12 when supply pressure thereof is at a prescribed level or higher. From then on, a pump operation starts and the fluid is discharged from a pump impeller 15, partially flowing through the back of the impeller 15, and flows into the gas seal chamber 12 via the communication hole 42. The fluid in the gas seal chamber 12 flows, by the amount flown therein, in an auxiliary pump chamber 36 from a communication hole 32 through an axially penetrating portion 26. Further, the fluid flows in, via a communication hole 38, to the back of the pump impeller 15, joins to fluid flowing directly from an outlet of the pump impeller 15 along its back, and circulates in the inlet side of the pump impeller 15 from a communication hole 44.
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