【Daily Question】Hydrogen production and hydrogenation technology version 20190629
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Participation: Prize 1 Wealth； Correct answer: Reward of 3 wealth points ； Note: This post is valid for 48 hours. https://bbs.hcbbs.com/static/image/hrline/2.gif Multiple-choice question: When starting a gear pump, it is necessary to ( ). A. The inlet and outlet valves are open. B. The inlet and outlet valves are closed. C. The inlet valve is open, the outlet valve is closed. D. The outlet valve is open, the inlet valve is closed. Answer: A. Your participation is the greatest support for our work. Giving roses to others leaves a pleasant fragrance in one’s own hands. https://bbs.hcbbs.com/static/image/hrline/1.gif https://bbs.hcbbs.com/static/image/hrline/2.gif Note: The answers will be published automatically after two days.
A gear pump belongs to the category of positive displacement pumps and cannot hold pressure