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石棉水泥管接头的种类很多,但总的来说,可分为套管式接头与法兰、套筒式接头二大类。现将此二类中的主要者简要介绍于后。(一)套管式接头(1)简易接头(双凸缘套管接头)。由一个石棉水泥套管和一对断面为圆形的橡胶圈所组成(图L_a)。套管二端各有一个凸缘,其中一个内径较大,称为工作凸缘,另一个内径较小。利用专门的安装工具,使橡胶圈由工作凸缘套入套管内壁压缩橡胶圈而起密封作用,其试验水压一般可达20气压,这种接头的优点是结构简单,施工方便。缺点是:对管端与套管的加工要求严格,误差不能过大,否则,安装时易使套管胀破,或使橡胶圈不能充分压突而降低接头的严密性。管端要求干燥,否则安装时橡胶圈位置不易正确。由于套管内
There are many types of asbestos cement fittings, but in general, they can be divided into two categories: sleeve joints and flanges and sleeve joints. The main ones in these two categories are briefly introduced later. (1) Jacketed joints (1) Simple joints (double flanged joints). It consists of an asbestos cement casing and a pair of round rubber rings (figure L_a). Each of the two ends of the sleeve has a flange, one of which has a larger inner diameter called a working flange and the other has a smaller inner diameter. Using a special installation tool, the rubber ring is sealed by the working flange sleeved into the inner wall of the sleeve to compress the rubber ring. The test water pressure is generally up to 20 bar. The advantage of this joint is that the structure is simple and the construction is convenient. Disadvantages are: strict requirements on the processing of the pipe end and the casing, the error can not be too large, otherwise, the casing is easy to burst when installed, or the rubber ring can not fully crush and reduce the tightness of the joint. The pipe end is required to be dry, otherwise the position of the rubber ring during installation is not easy to be correct. As the inside of the casing