【Daily Question: Pump Equipment】Weekly Summary 2018.12.2

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This post was last edited by 3983596_FPPZ on 2019-1-19 09:45. Monday (2018.11.26): https://bbs.hcbbs.com/thread-2166493-1-1.html Metal flexible diaphragm couplings are a common type of coupling. Which of the following statements is correct? (B) A. The more holes there are on the diaphragm, the better the coupling’s compensatory ability. B. The more holes there are on the diaphragm, the greater the torque that can be transmitted. C. The longer the intermediate section (extension section), the worse the coupling’s compensatory ability. D. Vibration reduction by a coupling means that it can eliminate vibrations. Tuesday (2018.11.27): https://bbs.hcbbs.com/thread-2168101-1-1.html The specific gravity of the fluid being transported has a direct impact on which of the following parameters? (CE) A. Flow rate B. Head C. Outlet pressure D. NPSHA E. Shaft power. Wednesday (2018.11.28): https://bbs.hcbbs.com/thread-2169949-1-1.html When selecting a pump, which of the following conditions must be met? (ABCDE) A. The pump’s NPSHR must be less than the system’s NPSHA. B. The flow rate must meet the required value. C. The outlet pressure must meet the required value. D. The motor power must not exceed its capacity. E. The material in contact with the fluid must be resistant to corrosion by that fluid. Thursday (2018.11.29): https://bbs.hcbbs.com/thread-2171817-1-1.html Regarding the balance of radial forces in a centrifugal pump’s rotor system, which of the following statements is correct? (BD) A. Centrifugal pumps can balance radial forces through their double-suction impellers. B. Pumps with double volute channels can balance radial forces. C. Multi-stage pumps can balance radial forces by arranging the impellers symmetrically. D. The radial guide vanes in the pump’s internal channels can balance radial forces. Friday (2018.11.30): https://bbs.hcbbs.com/thread-2173478-1-1.html What factors are directly related to the displacement of a reciprocating pump? (Multiple choice): A. Stroke length B. Size of the safety valve C. Operating frequency D. Cylinder diameter E. Number of cylinders F. Discharge pressure. Saturday (2018.12.1): https://bbs.hcbbs.com/thread-2175418-1-1.html The starting methods for the electric motor that drives the pump include (ABC): A. Direct start B. Reduced-voltage start C. Soft start (which can be considered a form of variable-frequency start) D. Quick start. This summary post gathers together the “One Question per Day – Pump Equipment” posts from the past week; you can review them here. No need to reply with scores