引言为了更好地控制挥发性有机化合物（VOCs 控制），RAYS 推出了一系列符合 API 624 和 API 641 标准的低泄漏逸散排放闸阀、球阀、截止阀和蝶阀，同时也可以满足 ISO 15848、TA-LUFT 和 MESC SPEC 77-312 标准。低泄漏逸散排放阀门逸散排放是指由于设备故障、泄漏或其他不可预见事件导致的来自加压设备的气体或蒸汽排放。这些排放大多来自工厂、发电厂、炼油厂和化工厂等工业场所。由于这些设施中潜在泄漏源众多，且检测和修复难度较大，因此逸散排放可能会带来严重的后果，包括：与商品损失相关的经济成本；环境破坏，例如空气污染和温室效应；由于暴露于危险物质和挥发性有机化合物（如苯）而对工人和靠近工业设施的当地社区居民造成长期健康风险；在含有大量受压易燃物质的爆炸性环境中，火灾和爆炸的风险更高。RAYS 专注于两项主要衡量阀门和填料产品排放水平的标准——API 641 和 ISO 15848-1:2015，并描述了 RAYS 阀门如何经过测试和认证以满足这些标准，例如 Trunnion 球阀、双截断与排放球阀、低温球阀和轨道球阀、API 600 闸阀等。API 641“四分之一转阀门的逸散排放型式测试”API 641 标准专门适用于四分之一转阀门。该标准适用于所有阀杆密封材料，规定了严格的最高允许泄漏量为每体积的 100ppm（百万分之一），并使用甲烷作为测试介质，采用 EPI 方法 21 来测量排放。需要注意的是，美国环境保护署（EPA）仅承认 API 641 排放测试。该标准要求进行 610 次机械循环和 4 次热循环，以评估阀门在其预期的五年使用寿命内的排放性能。在 A 组测试标准下，温度在环境温度和 260C（500F）之间交替变化，并在 600 psig 的恒定压力下进行。在循环开始之前，会进行一次静态排放测量，随后在测试过程中进行 14 次静态泄漏测量和 7 次动态泄漏测量。四分之一转阀门是基于阀杆的四分之一转来开启和关闭的，例如 DBB 球阀、DBB 插塞阀、三偏心蝶阀、低温球阀等。ISO 15848-1:2015“工业阀门——逸散排放的测量、测试和认证程序”ISO 15848 标准的第一部分概述了用于测量隔离和控制阀门的阀杆/轴密封和阀体连接处泄漏的测试和认证程序，这些阀门用于含有挥发性空气污染物或危险流体的环境中。根据该标准，阀门必须从 40% 开度循环至 60% 开度，并根据特定的紧密性等级、耐久性等级和温度等级进行测试：紧密性等级：使用氦气或甲烷作为测试流体进行测量，并为每个等级的最高允许泄漏量制定标准；耐久性等级：阀门在成功达到至少最低紧密性等级的允许泄漏量时完成的循环次数；温度等级：适用于不同的温度范围。工业阀门包括各种类型的阀门，例如 API 600 闸阀、BS 1873 截止阀、BS 1868 止回阀和 API 594 止回阀等，还包括四分之一转阀门，如球阀和蝶阀。RAYS 能做什么？通过先进的加工设备和测试仪器，RAYS 严格控制阀杆表面粗糙度，其值为 0.4~0.8μm，填料盒表面粗糙度为 1.6~3.2μm。所选用的石墨填料来自通过 API 622 认证的供应商和产品型号。每个阀门都在 RAYS 工厂的实验室中通过氦质谱仪进行测试。阀门的外部泄漏量小于 100ppm，挂上特殊铭牌后才允许出厂。RAYS 还可以根据不同的逸散排放标准（如 ISO 15848、TA-LUFT、MESC SPEC 77-312 等）设计和定制产品。我们也欢迎第三方检验公司到 RAYS 工厂进行验收。为确保用户的安全可靠使用，RAYS 工厂将向用户提供质量保证证书、材料证书 EN 10204.3.1、逸散排放测试报告以及测试仪器的校准证书。产品描述名称：低泄漏逸散排放阀门类型：API 600 闸阀、API 6D 球阀、API 607 球阀、Trunnion 球阀、电动球阀、三偏心蝶阀、低温球阀、长颈球阀、液氮球阀等。具体类型：双截断与排放球阀、双重隔离与排放球阀、DBB 球阀、轨道式上升式球阀阀门标准：API 6D、API 608、API 607、API 6FA、ASME B16.34、GOST 和 EN/DIN材料：奥氏体不锈钢、锻钢和铸钢应用适用于各种应用场景，特别是在 VOCs 控制方面。低温球阀也适用。如需更多信息或咨询，请随时联系 RAYS FLOW CONTROL。…

Since the modern industrial revolution, the global economy has developed by leaps and bounds. At the same time, mankind has paid a more painful environmental cost. With the increase of greenhouse gas emissions, extreme weather has become more and more common, and it seems to be the inescapable fate of mankind.The main culprit of environmental pollution and the greenhouse effect are industrial greenhouse gases and pollutants emitted into the atmosphere. In order to alleviate the environmental impact of global industrialization, strategies to control volatile gas emissions have been implemented internationally, and international standards or norms have been formed. While some developed countries have taken the lead in environmental control, we have also issued and implemented standards for FE valves, and are increasingly accepted by users. Every two years, “FUGITIVE EMISSIONS SUMMIT CHINA” takes place within the global industry while sharing their: experience, technology, and innovation on the topic of escape leakage control and LDAR practice. It is precisely because of the release of such relevant standards and the organization of activities that the standardization of fugitive emission has been more widely studied and developed.Fugitive emission refers to the emission of any chemical substance or compound in any physical form from an unanticipated or untrue leakage of equipment in an industrial site. The scientific dictionary defines fugitive emissions as Contaminants released into the atmosphere due to leakage, evaporation or wind, as well as several concepts related to them – such as low-evaporation of organic compounds. Typical chemical plant leak sources include valves (packing, bonnet connections), pump seals, compressors, flanges/joints, and safety/pressure relief devices.Valve leakage includes external leakage and internal leakage. The general leakage evaluation standard for valves is the visible leakage of the valve. However, fugitive emission strictly refers to invisible leakage, which needs to be detected by means of instruments, and often refers to leakage in packing area and gasket area. Gasket area is generally static seal and easy to control/diffuse leakage. Packing area is a dynamic seal and the movement of valve stem is easy to cause packing leakage.Generally speaking, the main factors affecting the valve packing leakage are as follows:TemperatureThe packing has a higher expansion value at a higher temperature than the metal member in contact therewith, and the packing is compressed. If the packing can pass the fugitive test at normal temperature, it can pass the fugitive test at high temperature (the loss rate of the filler itself is small), so the packing can easily pass through at the first normal temperature and the first high temperature. If the temperature is lowered from the first high temperature of 400 C to the second room temperature test, the shrinkage of the packing is larger than that of the metal part, but the cavity of the packing is unchanged compared with the first room temperature condition. Theoretically, the volume of the graphite packing is also unchanged. However, after high temperature, the packing has a certain loss of burning, so the inside of the packing will become loose. Then the resilience of the packing will decrease, and the stress inside the packing will be lowered after the high temperature drops to normal temperature. The torque of the pressure plate bolt is reduced, which is easy to cause leakage. However, by applying the packing to the torque value at the first room temperature, the original leak rate can be satisfied.Valve position toleranceThe shape and position tolerances of the parts that have an influence on the packing fugitive test are: the straightness of the valve stem, the machining position tolerance of the valve cover and the stem nut, and the assembly error. The accumulation of error eventually causes the valve stem to deflect at an angle to the packing. The side pressure of the packing rod in the reciprocating motion is constantly changing, and it is easy to cause leakage in a place where the side pressure is small. Also, after a certain number of reciprocating movements of the valve stem, the continuous extrusion of the packing causes the effective clearance of the inner hole of the packing to become larger, resulting in easier leakage.Stem, packing gland surface finishThe smoother the stem and packing gland, the easier the packing will seal. The tiny unevenness of the graphite-filled metal surface is much easier. From the economic analysis that satisfies the seal and valve manufacturing, the surface finish of the stem is generally Ra0.4-0.6 μm, and the surface finish of the packing gland is generally set to Ra1.6-3.2 μm.Gland, stem clearance, packing gland, and gland clearanceValve design and manufacturing should ensure that the gap between the gland and the valve stem is greater than the gap between the packing gland and the gland. This is to ensure that the valve stem will not bite with the gland during the movement. Although the gap between the gland and the valve stem is smaller, the packing is easier to seal, but the gap between the gland and the valve stem should not be too small. Due to the manufacturing error of the valve, too small of a gap is likely to cause a bite on the valve stem. Due to the presence of the packing end ring, maintaining a proper clearance between the gland and the stem does not cause the packing to leak beyond the standard.The environmental impact of the valve during use is an important indicator to evaluate the performance of the valve. Among them, the fugitive emission index of the valve is an important parameter to evaluate the environmental protection of the valve. The FE requirement of the valve has become the basic requirement for valve design and manufacture.In 2015, the API600 standard, widely used in the valve industry, first added the API 624 to the standard text for the valve’s FE test. With the Chinese National Standard (GB), the valve standard for hydro-treating units has also clearly required FE testing in accordance with ISO15848.ISO15848, VDI2440, API624, MESC SPE77/312, etc. are FE standards that are widely used in the valve field. These standards are based on helium or methane gas as a leak detection medium and are detected by proton spectroscopy. The sensitivity is usually 10-12 Pa*m3*s-1.Fugitive Emission is not a new topic. Although society’s concerns about air quality and environmental issues continue to heat up, the petrochemical industry’s application of FE control, leak detection, and repair technology have only just begun in recent years. Undoubtedly, the requirements for FE testing and evaluation have promoted the continuous improvement of industrial development. As far as the valve industry is concerned, the precision of machining and the quality of seals continue to improve. Thus, FE valves will gradually become the mainstream of the high-end valve market.…