问题 问答题 案例分析题

某施工单位承担的一项机电安装工程进入单机试运行阶段。项目部计划对一台解体出厂、现场组装的大型裂解石油气压缩机进行试运行,该压缩机转速为5850r/min。试运行前进行检查,确认试运行范围内的工程,压缩机出口管道系统设计压力为11.2MPa,组对焊接工作已经结束,除少量固定焊口外,无损检测也基本结束,其他相关工程已全部完成,并按质量验收标准检查合格。由于工作量大,出口管道在10日内也不能完成所有工作。由于这台压缩机的试运行影响后续动设备的试运行。项目部认为,机组本体试运行条件具备,仅出口管道系统还存在一些尾项,对压缩机试运行影响不大,决定立即进行该压缩机的试运行。

压缩机按照规范的规定进行空气负荷试运转,在排气压力达到3/4额定压力运转40分钟后,出口管道中有一道焊口泄漏,多道法兰接口严重泄漏,试运行中止。试运行班组作业人员在管道安装班组的配合下,将出口管道从压缩机法兰处卸开,对管道泄漏部位进行补焊或处理。处理完成后,将出口管重新与压缩机连接并继续进行试运,运转时将排气压力直接升到3/4额定压力,运转了1小时20分钟后,试运行班长认为在此压力下总计运行时问达到了规定的2小时,决定将压力升至额定压力运行。达到额定压力后,压缩机发生较大振动,运动部件有异常响声。试运行结束后复查压缩机位移值超标,不符合压缩机单机试运行的要求。

分析压缩机发生较大振动,运动部件有异常响声和试运行结束后压缩机位移值超标与试运行中止后的处理过程和管线复位的操作有何关系。

答案

参考答案:出口管道卸开后重新与压缩机连接时,应监视和测定机器的位移,当测出超过规范允许的偏差时,应松开管道法兰再次找正压缩机并调整管道后重新连接,再行检查,直至合格为止。出1t管复位与压缩机重新连接时没有监测机器的位移值,在连接后可能给压缩机产生了附加外力,致使其在非正常的附加负荷下运转,这是运行时振动较大的重要原因。同时,没有逐级升压也对运转不正常有影响。

阅读理解

Some scientists say that animals in the ocean are increasingly threatened by noise pollution caused by human beings. The noise that affects sea creatures comes from a number of human activities. It is caused mainly by industrial underwater explosions, ocean drilling, and ship engines. Such noises are added to natural sounds. These sounds include the breaking of ice fields, underwater earthquakes, and sounds made by animals themselves.

Decibels(分贝) measured in water are different from those measured on land. A noise of 120 decibels on land causes pain to human ears. In water, a decible level of 195 would have the same effect.

Some scientists have suggested setting a noise limit of 120 decibles in oceans. They have observed that noises above that level can frighten and confuse whales.

A team of American and Canadian scientists discovered that loud noises could seriously injure some animals. The research team found that powerful underwater explosions were causing whales in the area to lose their hearing, which seriously affected the whales’ ability to exchange information and find their way. Some of the whales even died. The explosions had caused their ears to bleed and become infected(感染的).

Many researches whose work depends on ocean sounds disagree with a limit of 120 decibels. They say such a limit would mean an end to important industrial and scientific research.

Scientists do not know how many and what kinds of noises are harmful to ocean animals. However, many scientists suspect that noise is a greater danger than they previously believed. They want to prevent noises from harming creatures in the ocean.

小题1:The second paragraph mainly tells us that the noises on land and in water       .

A.are both from human activities.

B.both do harm to sea animals

C.are measured differently

D.have the same effect on humans小题2:As to(依据) the effects of noises on whales, which of the following statements is TRUE according to the passage?

A.They are deaf to noises.

B.Noises at a certain level may hurt them.

C.They are easily confused by noises.

D.Noises will limit their ability to reproduce.小题3:Many researchers think that the noise limit of 120 decibels would        .

A.protect whales from noises

B.benefit them a lot in their research work

C.do good to their health

D.increase industrial output小题4:What will scientists most probably do in the future?

A.Count the number of sea animals.

B.Stop their research on the ocean.

C.Study the effect of different noises.

D.Protect sea creatures from harmful noises.

多项选择题