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原文：
Valve spring preload FT passes through the stem above the valve flap, and the system pressure within the medium in the disc below, the role of the FT underBall Valves the valve sealing surface and the nozzle valve sealing surface tightly integrated to serve sealing effect. When the system of media balance the force Fx and the FT, the valve began to take off, that is, beginning the safety valve seat. Off the pressure is equal to, where f that the internal parts of the mechanical valve friction. When the safety valve discharge buck off until the boiler pressure vessel of the media reduced to the role of the force on the valve flap is less than springPlug Valves force, the safety valve to close the back seat, the result is to ensure that the provisions of the pressure of the boiler equipment range. 1.2Crosby flexible valve flap of the structural characteristics of spring-loaded safety valve As Crosby has a flexible spring type safety valve valve valve valve valve sealing surface in the processing of a circular dorsal groove, which makes the sealingSafety valves surface of the valve flap has some flexibility, so this type of disc called "flexible valve flap . " From the structural comparison, flexible valve flap flap valve for the advantages of ordinary plane is: ① reduce the role of stem strength points, sealing performance improvement. Ordinary plane flap valve stem force will not only higher than the sealing surface, and non-directly on the disc. For the flexible valve flap valve, the valve stem points down to force the sealing surface below, but also directly on the valve flap. This structural improvement of ability of the valve a substantial increase in anti-shock, that is, a substantial increase seal stability. In other words, thereGlobe Valves is the same degree of shock in the valve where the flexible valve flap valve less prone to leakage. This performance has been tested in actual operation the safety valve. ② "flexible valve flap" structure not only improves the operation sealing performance, but also improve the value of maintaining the operating pressure seal. For the design of ordinary flat disc, when running on the pressure rise to the valve set pressure (set pressure of 95%), the valve will be a "pre-discharge." For the spring-loaded safety valve, the "pre-discharge" is normal existence, and "pre-discharge," the existence of a certain extent, help the spring-loaded safety valve off. So Crosby will design the pressure relief valve spring and the maximum operating pressure difference as more than 5%. "Flexible valve flap" structure into the system pressure valve annular valve sealing surface of the dorsal groove, and the role of flap valve sealing surface with a relatively circular ramp, due to the sealing surface has a certain flexibility, as the media pressure within the system increased disc sealing surface pressure is the system generated by pushing down small deformation, andForged Steel Valves close integration with the sealing surface of the nozzle, thus pre-vent valve point delay. In ensuring accurate set pressure valve under the premise of "flexible valve flap" structure allows the valve to set pressure at the operating pressure of more than 96% is still no leak. Through our spring-loaded safety valve setting Crosby verify the results of statistics showed that the flexible valve flap valve of the pre-discharge point of the set pressure can reach 98.5% or 99%, and accurate take-off, back seat altogether, no leakage.
原文来自： http://www.shreveporttimes.com/article/20091205/NEWS01/91205007/1060

“Gas line valve release investigated”是由上海天阀实业有限公司提供的阀门新闻，中文译文仅供参考，以下提供站内导航搜索：

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以下是参考译文：

译文：普通平面阀瓣的阀杆力作用点
安全阀弹簧的预紧力FT通过阀杆传递给阀瓣上方，而蝶阀系统内介质的压力作用在阀瓣下方，在FT的作用下阀瓣的密封面与喷嘴密封面紧紧结合，从而起到密封作用。当系统的介质的作用力Fx与FT平衡时，阀门开始起跳，即安全阀开始起座。起跳压力等于，其中f表示阀门内部零件的机械摩擦力。当安全阀起跳排放降压，直至锅炉容器内的介质的压力降低到作用于阀瓣上的力小于弹簧的作用力时，安全阀才能回座关闭，其结果是保证锅炉设备在规定的压力范围内工作。 1．2Crosby柔性阀瓣的弹簧式安全阀的结构特点由于Crosby具有柔性阀瓣的弹簧式安全阀是在阀瓣密封面背侧加工了一道呼吸阀环形的凹槽，这就使阀瓣的密封面具有一定的弹性，所以这类阀瓣叫做“柔性阀瓣”。从结构上比较，柔性阀瓣对于普通平面阀瓣的优点在于： ①降低了阀杆力的作用点，密封性能提高。普通平面阀瓣的阀杆力作用点疏水阀不但高于密封面，而且非直接作用在阀瓣上。对于柔性阀瓣的阀门，阀杆力作用点降低到密封面以下，而且直接作用在阀瓣上。这种结构上的改进使阀门的抗震动能力大幅提高，也就是密封稳定性大幅提高。换句话说，在阀门存在相同程度震动的情况下，柔性阀瓣阀门更不容易发生泄漏。这种性能已在安全阀实际运行中得到验证。 ②“柔性阀瓣”结构不但提高了运行密封性能，而且提高了保持密封性的运行压力值。对于设计普通平面阀瓣，当运行于压力升高到阀门设定压力(即整定压力的 95％)时阀门会出现“预泄”。对于弹簧式安全阀来说，“预泄”的存在是正常现象，而“预泄”的存在在一定程度上可以帮助弹簧式安全阀起跳。因此克罗斯比公司将弹簧式隔膜阀安全阀的设计压力与最大运行压力的差值定为5%以上。“柔性阀瓣”结构将系统压力导入阀瓣密封面背侧的环形的凹槽并作用在与阀瓣密封面相对的环形斜面上，由于密封面具有一定的弹性，随着系统内介质压力的升高，阀瓣密封面被系统的压力向下推压产生微小变形，并与喷嘴密封面紧密结合，从而使阀门预泄点推迟。在保证阀门旋塞阀整定压力准确的前提下、“柔性阀瓣”结构可以使阀门在柱塞阀运行压力达到设定压力96％以上仍然无泄漏。通过我们对Crosby弹簧式安全阀整定校验的结果统计表明，柔性阀瓣的安全阀的预泄点可以达到了针型阀整定压力的98.5％甚至99％，而且起跳准确、回座干脆、无泄漏现象。

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