问题 问答题 简答题

烧碱、动力的制冷机组是螺杆压缩机,那么螺杆压缩机工作原理是什么?

答案

参考答案:

工作原理:螺杆式压缩机属容积式压缩机,是通过工作容积的逐渐减少来达到气体压缩的目的。

螺杆式压缩机的工作容积是由一对相互平行放置且相互啮合的转子的齿槽与包容这一对转子的机壳所组成。在机器运转时二转子的齿互相插入对方齿槽,且随着转子的旋转插入对方齿槽的齿向排气端移动,使被对方齿所封闭的容积逐步缩小,压力逐渐提高,直至达到所要求的压力时,此齿槽方与排气口相通,实现了排气。

单项选择题

Lying in the sun on a rock, the cougar(美洲狮) saw Jeb and his son, Tom, before they saw it. Jeb put his bag down quickly and pulled his jacket open with both hands, making himself look big to the cougar. It worked. The cougar hesitated, ready to attack Jeb, but ready to forget the whole thing, too.

Jeb took off his jacket, grasped Tom and held him across his body, making a cross. Now the cougar’ s enemy looked even bigger, and it rose up, ready to move away, but unfortunately Tom got scared and struggled free of Jeb.

"Tom, No !" shouted his father.

But Tom broke and ran and that’ s the last thing you do with a cougar. The second Tom broke free, Jeb threw himself on the cougar, just as it jumped from the rock. They hit each other in mid-air and both fell. The cougar was on Jeb in a flash, forgetting about Tom, which was what Jeb wanted. Cougars are not as big as most people think and a determined man stands a chance, even with just his fists. As the cougar’s claws got into his left shoulder, Jeb swung his fist at its eyes and hit hard. The animal howled(吼叫)and put its head back. Jeb followed up with his other fist. Then out of the comer of his eye, Jeb saw Tom. The boy was running back to help his father.

"Knife, Tom," shouted Jeb.

The boy ran to his father’ s bag, while Jeb started shouting as well as hitting, to keep the cou-gar’s attention away from Tom. Tom got the knife and ran over to Jeb. The cougar was moving its head in and out, trying to find a way through the wall. Jeb was making out of his arms. Tom swung with the knife, into the cougar’ s back. It howled horribly and ran off into the mountains.

What do we know about cougars().

A. They are afraid of noises.

B. They hesitate before they hit.

C. They are bigger than we think.

D. They like to attack running people.

单项选择题