问题 单项选择题

城市垃圾卫生填埋厂的HDPE渗沥液收集管(带孔,又称花管)道连接采用()方式。

A.法兰连接

B.热熔焊接

C.承插口连接

D.胶圈连接

答案

参考答案:B

解析:考点为城市垃圾卫生填埋厂施工内容。城市垃圾卫生填埋厂的渗沥液收集管(带孔,又称花管)道,通常采用硬质聚乙烯(HDPE)管材,管道连接采用热熔焊接方式。管道热熔焊接连接一般分为以下五个阶段:切削管端头:用卡具把管材准确卡到焊机上,擦净管端,对正,用铣刀铣削管端直至出现连续屑片为止。对正检查:取出铣刀后再合拢焊机,要求管端面间隙不超过1mm,两管的管边错位不超过壁厚δ的10%。接通电源:使加热板达到210±10℃,用净棉布擦净加热板表面,装入焊机。加温融化:将两管端合拢,使焊机在一定压力下给管端加温,当出现0.4~3mm高的融环时,即停止加温,进行无压保温,持续时间为壁厚艿(mm)的10倍(s)。加压对接:达到保温时间以后,即打开焊机,小心取出加热板,并在10s之内重新合拢焊机,逐渐加压,使融环高度达到(0.3~0.4)δ,单边厚度达到(0.35~0.45)δ。保压冷却:一般保压冷却时间为20~30min。需要专业焊接机和有资质焊工进行操作。

名词解释
阅读理解

The world would be a very different place if someone hadn’t invented the lift. There would be few, if any, high-rise buildings because people would refuse to climb many stairs. By the time workers reached their offices on the top floors of a tower building, it would be time to go home – if they were not too tired for the long walk down!

The first lift that we know about was used by the Greek scientist, Archimedes, in about 230 BC. It was a simple place that could be pulled up and down with a rope. A lift like this was used much later in the 12th century by priests who lived on top of a mountain at Metereo in Greece. Because they were afraid of killers, the priests had not built any stairs up the mountain. The only way up was by lift, which priests worked from the top of the mountain.

A few hundred years later, a Frenchman, Villayer, invented a ‘flying chair’ which used a rope and a place. A number of rich people had these ‘flying chairs’ built in their homes, including Queen Anne of England in Windsor Castle and Louis XVI of France at Versailles. Unluckily, Louis’ daughter was badly hurt when using one of the chairs, and Villayer ran away, afraid that he would be punished.

The main problem for lift engineers was that either humans or animals were needed to pull the ropes. This problem was not worked out until the discovery of steam power. But even steam powered lifts were not always safe because they also used ropes which sometimes broke. If the rope broke - which it sometimes did - the lift fell to the ground and people in it were killed or hurt. This problem worked out in 1854 when an American, Elisha Otis, invented something which stopped the lift from falling if the rope broke. At first Otis lifts were used only in factories, then in 1857 he built one in a large New York store. Now lifts use electric power and are completely safe. They also travel very quickly. Some lifts travel faster than 60 kilometers an hour.

小题1:The writer thinks that lifts are important today because __________.

A.people like playing on them

B.they are the best way of using steam power

C.we need them for tall buildings

D.workers are lazy小题2:The 12th century priests had a simple lift instead of stairs because ___________.

A.they thought the stairs were broken

B.they liked having stairs and a lift

C.the lived at the bottom of a mountain

D.they were afraid of killers小题3:Villayer thought he would be punished because ____________.

A.poor people could not afford his ‘flying chair

B.someone was hurt in one of his ‘flying chairs’

C.his ‘flying chair’ did not work at all

D.he ran away with Louis XVI’s daughter小题4:Steam power meant that ________  .

A.they did not need a living thing to pull the ropes

B.Elisha Otis could invent a lift that would not fall

C.the rope always broke

D.they could use lifts in factories