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A hot air start pipe indicates that there is （）.

A、inefficient cooling

B、a leaking air start valve

C、a clogged drain valve

D、a leaking air bottle

时间：2022-01-04 16:09 关键词：船舶动力装置海船船员考试

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underline的意思是:draw a line under to give emphasis or indicate special type
我国海船船员考试发证等规则的制定，是以（）公约为主要依据的。
第二组Under normal operation, some lubrication oil mist may be discharged from the air compressor to the air start system. This oil may be from excess compressor cylinder lubrication, from faulty oil scraper rings, or may even be suspended oil vapor contaminating the engine room atmosphere and drawn in at the compressor suction. Oil discharge is kept to a minimum by draining the after cooler, air receiver and starting system. If small quantities of lubrication oil do get passed into the starting air system, they will deposit as thin moist film over internal pipe surfaces but are not readily combustible. If a cylinder non-return valve leak while the engine is in operation, some hot gas, possibly with unburned fuel and cylinder lubrication oil, may be blown through the valve to the adjacent air manifold. With further heating from the leaky valve, this, together with the already deposited oil film, will carbonize and form. incandescent carbon. If starting air is applied to the system while still hot, the high pressure air coming into contact with the burning carbon may cause an explosion. Such an explosion will cause a flame to pass back through the air start pipe system, evaporating the deposited oil film and igniting it in the presence of air. Very high velocities and shockwaves are generated which may rupture pipes and fittings.Alternatively, if excessive oil has entered the air start system, a mixture of air and oil droplets may be discharged through the open cylinder non-return valve during starting. This spray may ignite due to high temperatures in the cylinder, causing a flame through the still open valve to the air manifold.To prevent an explosion, air start valves must be correctly maintained and lubricated to ensure correct timing and free movement with positive closing. Oil in the system must be kept to a minimum, pipe lines must be drained and cleaned internally when necessary and oil discharge from air compressors must be kept to a minimum by good maintenance.The passage is mainly about
－ What does the sign over there read － “No person ________ smoke or carry a lighted cigarette, cigar or pipe in this area”
《中华人民共和国海船船员船上培训管理办法》中的船上培训是指申请三副、三管轮适任证书的船员通过理论考试后在船舶上进行的（），以及申请船长、轮机长、大副、大管轮适任证书的船员通过理论考试后在船舶上进行的（）。