【Daily Question】Pump Equipment Technical Exchange Edition 20180404
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This post was last edited by foam_ZPTK on 2018-4-4 at 14:56. Participants: Prize 3 Wealth； Correct answer: Reward of 10 wealth points ； Note: A reward of 10 wealth points will be given for correct answers within 48 hours; this post is valid for 48 hours. Multiple-choice question: Centrifugal pumps should be started by closing the (small) valve, while mixed-flow pumps should be started ( ). A. Open the valve B. Close the valve C. Either option is acceptable. Correct answer: C. According to the domestic formula for specific speed, the specific speed of a mixed-flow pump is 300
Centrifugal pumps should be started by closing the (small) valve, whereas mixed-flow pumps should be started (C). A. Open the valve B. Close the valve C. Either works
The circulating water pump is one of the key auxiliary devices in power plants, and its operational reliability is crucial for the safe operation of the units. Due to its characteristics such as low head and high flow rate, the mixed-flow pump is widely used in China. Circulating water pumps of the mixed-flow type must not be started with the valve closed. When starting, the outlet valve must first be opened to a certain degree before the circulating water pump can be started, in order to prevent damage to the pump ； When shutting down the pump, it is necessary to first close the outlet valve of the circulation water pump to a certain degree before stopping the pump. Due to the large diameter of the outlet pipeline of the power plant circulation water pump, liquid-controlled butterfly valves are commonly used as the outlet valve for such pumps. The schematic diagram of the liquid-controlled butterfly valve at the outlet of a typical circulating water pump is shown in Figure 1
Centrifugal pumps should be started by closing the (small) valve, while mixed-flow pumps should be started (A). A. Open the valve B. Close the valve C. Either works