问题 问答题 简答题

简述移动式空气压缩机的工作原理。

答案

参考答案:

空气压缩机通皮带轮由原动机拖动,并以一定速度转动,机内曲轴连杆活塞机构将曲轴的转动转变为活塞沿缸简内壁的往复(上下)运动。经空滤器的常压空气由进气阀进入缸体,并被压缩为一定压力后,通过排气阀进入储风简。如此周而复始地循环,储风简内有源源不断的压力空气供给使用。

问答题 简答题
阅读理解

A simple piece of clothesline hangs between some environmentally friendly Americans and their neighbors.

On one side stand those who see clothes dryers (干衣机) as a waste of energy and a major polluter of the environment.As a result, they are turning to clotheslines as part of the “what-I-can-do environmentalism.”

On the other side are people who are against drying clothes outside, arguing that clotheslines are unpleasant to look at.They have persuaded Homeowners Associations (HOAs) access the U.S.to ban outdoor clotheslines, because clothesline drying also tends to lower home value in the neighborhood.

This has led to a Right-to-Dry Movement that is calling for laws to be passed to protect people’s right to use clotheslines.So far, only three states have laws to protect clothesline.Right-to-Dry supporters argue that there should be more.

Matt Reck, 37, is the kind of eco-conscious(有生态意识的)person who feeds his trees with bathwater and reuses water drops from his air conditioners to water plants.His family also uses a clothesline.But on July 9, 2007, the HOA in Wake Forest, North Carolina, told him that a dissatisfied neighbor had telephoned them about his clothesline.The Recks paid no attention to the warning and still dried their clothes on a line in the yard.“Many people say they are environmentally friendly but they don’t take matters into their own hands,” says Reck.The local HOA has decided not to take any action, unless more neighbors come to them.

North Carolina lawmakers are saying that banning clotheslines is not the right thing to do.But HOAs and housing businesses believe that clothesline drying reminds people of poor neighborhoods.They worry that if buyers think their future neighbors can’t even afford dryers, housing prices will fall.

Environmentalists say such worries are not necessary, and in view of global warming, that idea needs to change.As they say, “The clothesline is beautiful.Hanging clothes outside should be encouraged.We all have to do at least something to slow down the process of global warming.”

小题1:One of the reasons why supporters of clothes dryers are trying to ban clothesline drying is that ______.

A.clothes dryers are more efficient

B.clothesline drying reduces home value

C.clothes dryers are energy-saving

D.clothesline drying is not allowed in most U.S.states小题2:Who are in favor of clothesline drying?

A.Housing businesses.

B.Environmentalists.

C.Homeowners Associations.

D.Reck’s dissatisfied neighbors.小题3:What is mainly discussed in the text?

A.Clothesline drying: a way to save energy and money.

B.Clothesline drying: a lost art rediscovered.

C.Opposite opinions on clothesline drying.

D.Different varieties of clotheslines.