Seals can be polymer materials, asbestos or rubber seal material selection depends on the valve components of the transmission medium, operating temperature, working pressure and flow rate.

密封件可以是高分子材料、石棉或橡胶，密封件材料的选择取决于阀门所输送的介质成分、工作温度、工作压力和流速。

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Main USES asbestos pan-gen liquid ammonia acid and alkali, for if, water, oil medium, valves, pumps and piston and rod for anticorrosion seal.

主要用途石棉盘根用于若酸碱、液氨、水、油品介质、阀门、泵、活塞、杆作防腐密封。

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The governors and head teacher denied any blame for delay in work to seal or remove the asbestos.

BBC: Cwmcarn High School