Positive displacement, helical gear pumps are well suited for pumping oil because （）

A、A.stuffing boxes eliminate the leakage problems usually associated with other gear pumps

B、B.it is not necessary to closely maintain design clearances with this pump

C、C.they are essentially self-priming and produce a high suction lift

D、D.these pumps are designed with extreme tooth angled

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更多“Positive displacement, helical gear pumps are well suited for pumping oil because （）”相关的问题

第1题

[] Any action taken to avoid collision shall，if the circumstances of the case admit，（）.

A、A.be positive B、B.be positive and made in ample time C、C.be positive，made in ample time and with due regard to the observance of good seamanship D、D.be positive，made in ample time，with due regard to the observance of good seamanship and avoiding complying with local regulations

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第2题

[单选题] Centrifugal pumps are popular because they are very simple in construction,and produce smooth, constant, （） discharge.

A、non-pulsating B、pulsating C、positive D、non-positive

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第3题

[单选题] The original equilibrium position is stable when（）.

A、metacentric height is positive B、metacentric radius is positive C、KG exceeds maximum allowable limits D、free surfaces are excessive

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第4题

[单选题] The original equilibrium position is stable when（）.

A、metacentric height is positive B、metacentric radius is positive C、KG exceeds maximum allowable limits D、free surfaces are excessive