When installing the Series 4700, it is recommended that galvanized steel back up rings be used behind the valve flanges.
在安装系列4700夹管阀时，建议在阀门法兰后面采用镀锌钢支撑环加固。
Ball and valve seat rings are metal materials, sealing pressure than the large, rely on the media itself can not seal the pressure has reached the requirements to be imposed by external forces.
球体和阀座密封圈都采用金属材料制造，密封比压很大，依靠介质本身的压力已达不到密封的要求，必须施加外力。
To maintain the spool in the head and valve seat rings for tight closure is important.
保持阀芯头与阀座环对中，对于严密关闭是重要的。
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