成 人 网 站94免费观看-国产视频在线一区二区-欧美一级三级-www91在线观看-男女无遮挡猛进猛出免费观看视频-久久夜靖品2区-狠狠综合久久久久综合网址-亚洲精品乱码久久-国产成人精品亚洲一区-西西44rtwww国产精品-中文无码高潮到痉挛在线视频-久久久久久久久久久免费av-国产青青草视频-亚洲精品自产拍在线观看-久久免费成人

From May 10 to November 11, the Chinese Academy of Sciences held a meeting of experts in the development of the Institute of Instrument Research, and more than 20 instrument development experts attended the meeting. The conference mainly ...

How to connect the entire valve and pipeline or equipment, this problem can not be ignored, because the valve running, running, drip, leakage phenomenon, the vast majority occurred here.

The principle of maintenance during the operation of the valve is as follows: 1 Keep the outside of the valve and the active part clean and protect the integrity of the valve paint. The surface of the valve, trapezoidal threads on the stem ...

Taboo 1: the main materials, equipment and products used in construction, and lack of technical quality identification documents or product qualification certificates conforming to the current standards issued by the state or department...

At present, the butterfly valve, as a component used to realize on-off and flow control of pipeline system, has been widely used in many fields such as petroleum, chemical industry, metallurgy, hydropower and so on. In the ...

At the same time with dynamic balance and electric adjustment of two functions, and two functions simultaneously. The dynamic balancing electric regulating valve is installed on the return pipe of the combination air conditioner ...