问题 问答题 简答题

蒸汽管网水击的现象、原因及处理方法?

答案

参考答案:

现象:①现场能听见很响的水击声;②管道振动大;③蒸汽管道水击严重将造成管道移位法兰撕裂,管道焊缝断裂等严重后果。

原因:①投用蒸汽时没暖管,或暖管不充分;

②管网引蒸汽和系统蒸汽并网时没有充分暖管;

③管道疏水未投用,或疏水器坏;

④锅炉水或蒸汽凝液倒入蒸汽管网。

处理方法:①现场确认水击管线及位置;

②投用蒸汽引蒸汽和蒸汽并网前应辙底暖管;

③投用管道各疏水器。

完形填空

根据下面短文内容,在短文的空格处填上一个恰当的词,使短文完整、通顺。

Do you often like to use disposable (一次性的) chopsticks when   小题1: in restaurants? It’s time to drop this habit.

China produces 80 billion pairs of disposable chopsticks every year. “This is enough to cover Tian’anmen Square 363 times,” said Bai Guangxin, chairman of Jilin Forest Industry Group.

“The production of such chopsticks is a heavy burden (负担) on national forests,” Bai added. People need to cut     小题2: over 20 million 20-year-old trees to make way for this production.

Many people choose to use disposable chopsticks     小题3:  they think that they are cleaner. However, many disposable chopsticks are not as     小题4:  as people think. Some may even be toxic (有毒的), China Daily reported.

Several days ago, actor Huang Bo posted a message on his micro blog. He wrote that when he tried to wash the disposable chopsticks in a restaurant, he was     小题5: to find that the chopsticks turned the water yellow and gave off a bad smell.

Some scientists said the color and     小题6:  of the chopsticks may show that they have something harmful such as sulphur (硫磺) and other chemicals (化学品). That’s bad    小题7:    people’s health.

As Bai Guangxin suggested, it’s better that people carry their own chopsticks around. It doesn’t just help save the environment; it also   小题8:  our own health.

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