| 摘要 |
PURPOSE:To prevent the seizure of an impeller and to make it possible to operate in the condition of high performance by pouring cooling water into inside of the impeller through the center of a rotating shaft and keeping the clearance between this impeller and a casing constant by means of the flow control of this cooling water. CONSTITUTION:When a roots-form blower is operated while pouring water, by opening a manual operation valve, through a cooling water feed pipe 5, a branch pipe 4, passage 3a inside each rotating shaft 3, an inlet passage 2a to each impeller, inside 2 of each impeller, a discharge passage 2b of each impeller, passage 3a inside each rotating shaft 3, a branch pipe 4, a cooling water discharge pipe and a flow control valve 10, the temperature of the impeller 2 accords with the temperature of a cooling water flowing inside the cooling water discharge pipe 6. When this temperature comes to be an elevation limit water temperature 80 deg.C, a temperature sensor 12 operates and a water adjusting valve 8 opens to increase the flow rate, so the impeller 2 is cooled and a cooling water temperature is also lowered. And the cooling water again becomes the flow rate limited to pass through the flow control valve 10 by the operation of the temperature sensor 12, therefore the clearance between the impeller 2 and a casing is made possible to keep constant.
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