论文部分内容阅读
许多阀杆作滑动的工业调节阀时都采用石墨制品装填在阀杆与填料函之间而形成密封。在介质为高温水和蒸汽时,更是这样。最近,对几种成形石墨环进行试验,结果表明,采取通常的方法使用这些石墨环是非常不合适的。例如:一根标准的直径为0.5吋的往复运动阀杆,当采用普通的积层石墨环填料时,在600°F、400psi的蒸汽条件下,开关800次后泄漏速度已超过允许范围。而采用新近研究出的组合填料,使用同一阀门,在同样工况,开关45000次之后,泄漏速度仍在允许值以内。也就是说填料的使用寿命增加了五十倍。
Many valve stem for the sliding industrial control valve are used graphite products filled in the packing between the stem and packing to form a seal. This is especially true when the medium is hot water and steam. Recently several types of shaped graphite rings have been tested and the results show that it is not appropriate to use these graphite rings in the usual way. For example, a standard 0.5-in. Diameter reciprocating valve stem, with normal laminated graphite ring packing, has exceeded the permissible range after switching 800 times at 400 ° F steam at 600 ° F. The use of newly developed combination of packing, the same valve, in the same conditions, switching 45,000 times, the leakage rate is still within allowable value. This means that the life of the packing has increased by 50 times.