外文翻译--超高液压下Ｏ形环角密封的实验研究

1 Ultra-high hydraulic angle O-ring seal the experimental study Abstract : Nitrile rubber O-ring EHV end Kok containers sealed imposed on containers so high hydraulic seal experimental series. The results show that angle enclosed structure, as well as O-ring compression rate, diameter, enclosed space, rubber hardness, The sealing surface roughness and seal the form and position tolerances, and other relevant factors reasonable match, strict control, the use of ordinary O-ring can be achieved 138MPa ultrahigh static hydraulic seal. Keywords : EHV static O-ring seal Along with the rapid modern industrial development, UHP increasingly widespread use of the ultrahigh-pressure killing Hill, super-high-speed refrigeration, Expanded food industry, supercritical fluid extraction, low-salt treatment, Expanded room temperature and high pressure compression fermentation and other typical applications. Such equipment is produced by the many advantages of increasing peoples attention. If UHP food production is instantaneous pressure, role uniform, safe operation and low energy consumption to maintain good natural food color, smell and taste and nutritional characteristics of the components, with 21 new food simple, safe, natural, nutrition, health, and environmental protection in consumption demand. Which have significant social and economic benefits, has tremendous market potential and broad prospects for development. However, Chinas current UHP food production industries badly need to improve the level of equipment, can produce economic, Energy-saving, safe and efficient handling equipment constrains EHV food processing technology marketing major bottleneck. Among them, how to create economic EHV containers and ensure that the high pressure seal containers is particularly difficult lie. UHV equipment can operate normally sealed to a large extent depends on the integrity of the structure. High pressure sealing device about the 2 weight of the containers, weighing 10% to 30%. and the cost accounts for 15% 40% of the total cost, design sealed pressure vessel design is an important component. Because many UHV equipment for space operations, the operation requires not only material can be quickly loaded fast again. and the frequent requirement in the open despite repeated achieve reliable sealing, General use of fast open-closed structure since the close of this problem can be resolved. Ordinary rubber O-ring seal structure is simple, convenience, low cost, compact installation, easy to use and has since closed closely role advantages, the industry is widely used. So experiment nitrile rubber (NBR) O-rings (32.5 specifications for the 3.55G. implementation of the standards for GB3452.1-92) Kok sealed experiments. 1 O-ring seal from the Principle 1) state preload O-ring sealed site after its general section by a certain amount of compression, as O-rings have good flexibility, the interface will have a certain degree of contact pressure, thus achieving preload under seal. 2) state When the sealed chamber filled with hydraulic media, the role of media pressure, the O-ring to shift the low-pressure side, and the seal gap closed to live. With the increase of media pressure, the contact pressure has also been increasing, the peak is always greater than the fluid pressure. This will guarantee that the O-ring seal the sealing function, reflects the O-ring seal the ability to automatically sealed. Experience has shown that for ordinary rubber materials, generally 13 105Pa than the standard pressure. 2 the main parameters of Seal O-ring seal effects and compression rate, diameter, enclosed space, rubber hardness, The sealing surface roughness and seal the form and position tolerances, and other factors are closely related. The impact of O-ring seal properties of various factors, as long as the parameters of a design will reduce the unreasonable results sealed, even result in seal failure. Now, therefore discuss the impact of specific factors to determine the value . 1） compression rate After the O-shape link loads the seal spot, its section generally receives a quota the 3 compression, because the O shape link has the good elasticity, docking touches personally meets has the certain contact pressure, thus realizes under the pre- tight condition seal. 2) active status After the sealed chamber sufficiently enters the hydraulic pressure medium, in under the medium pressure function, the O shape link carries over a low pressure side, seals up the seal gap. Along with the medium pressure increase, the contact pressure also along with it increase, its peak value always is bigger than the fluid medium pressure. This has guaranteed the O shape packing ring seal function, also has reflected the O shape packing ring automatic sealing ability. The experience indicated that, regarding the ordinary rubber material, generally as the standard compares the pressure take 13105 P a. 3) seal gap O-ring gap in the high-pressure easily deformed easily be squeezed into the sealed space in order to cause damage, it is necessary to the O-ring seal gap to be strictly controlled. To prevent O-ring extrusion occurred, and to take into account the difficulty of installing and dismantling, The experimental space for the sealing of 0.1mm. 3 experimental devices and airtight structure 1) hardness Elastic modulus small O-ring, the maximum contact stress small, extrusion capacity, easy to destroy. So when a high pressure, high hardness should use the O-ring. In this experiment the O-ring hardness IRHD (International Rubber Hardness levels), 80 5.5) sealing surface roughness Seal the surface roughness is sealing technique to measure an important indicator. If the sealing surface Department has manufacturing defects or vertical scratch, it is very easy to seal leakage media. Ultrahigh Pressure Vessel Safety Technology Supervision provided EHV containers sealing surface roughness Ra should be less than or equal to 0 . 8 m. The experimental sealing surface roughness Ra from 0.4 m. 2) seals the form and position tolerances secret Sealed cylindrical surface of roundness, cylindricity tolerance by eight precision selection Hole-face vertical axis of tolerance by seven precision selection. 4 experiment 4 (1) O-ring uniform surface coating small grease. Cover and Arbors will use double-headed stud connection, and O-ring installed mandrels, Bolt pallets used to connect to the mandrels to compress O-ring； (2) high-pressure pipe assembly, and the small joints nut nuts, Nut will joints and hydraulic media entrance of the threaded connection； (3) under the pallets, containers and with the end caps on the map by a plate placed. Press access to power, two plate compactor next two pad； (4) access to power, preheat 5 minutes, Pressure relief valve rotation. 10 MPa to the differential pressure, pressure per-Level 5 minutes to observe any leakage； (5) Records Expander pressure on the indicator values and the hydraulic fluid leakage. several experiments show that, as long as a reasonable choice and strictly control the impact of the sealing performance of the main factors figure, Individual use of ordinary O-ring seal structure cone 138MPa can achieve a reliable seal； As laboratory equipment constraints, the experiment is just 138MPa hydraulic seal, O-ring seals that there is a potential to be tapped. This breakthrough of the traditional information that the O-ring seal maximum static pressure of 70MPa and when work pressure than Uniform Canada hubcap need to prevent extrusion of the limited space, it is worth further experiments. O-ring seal structure of cone-shaped O-ring seal and the corresponding surface of the manufacture of certain deviation compensation, This reduces the manufacturing of precision requirements, this seal structure should be promoted； O-rings in the completed several high pressure seal, found his appearance minor extrusion gap phenomenon. This shows that the O-ring is achievable 138MPa about EHV sealed But media pressure is required to consider increased use of O-rings with the triangular pad combination sealed structure or use other sealing pathways to solve, but this paper to explore the impact of sealing performance of the main parameters of methods, there is still a definite reference value. hubcap need to prevent extrusion of the limited space, it is worth further experiments. 5 超高液压下形环角密封的实验研究 摘 要 : 采用丁腈橡胶 O形环实现超高压容器端部角密封 ,对容器施加超高液压做系列密封实验。结果表明 ,采用角密封结构 ,并对 O形环压缩率、截面直径、密封间隙、橡胶硬度、密封面的粗糙度和密封件的形 位公差等相关因素进行合理匹配 ,严格控制 ,使用普通 O形环可以实现 138MPa超高液压的静密封。 关键词 : 超高压 O形环 静密封 随着现代工业的快速发展 ,超高压越来越广泛地运用到超高压杀茵、超高速冷冻、食品膨化工业、超临界流体萃取、低盐化处理、室温高压膨化以及加压发酵等典型应用场合。这类设备所生产的产品具有众多优越性 ,日益 引起人们的普遍关注。如超高压食品的生产具有瞬间加压、作用均匀、操作安全和耗能低能很好地保持食物天然的色、香、味和营养成分的特点 ,符合 21世纪新型食品简便、安全、天然、营养、卫生、环保的消费需求。因而有着显著的社会效益和经济效益 ,具有巨大的潜在市场和广阔的发展前景。 但是 ,现今我国的超高压食品的生产存在亟待提高工业装备水平的问题 ,能否制造出经济、节能、安全、高效的处理设备成为制约超高压食品处理技术市场推广的主要瓶颈。其中 ,如何经济地制造超高压容器并保证容器的超高压密封尤为难点之所在。超高压设备能否正常运行在很 大程度上取决于密封结构的完善性。高压密封装置的重量约占容器总重的 10% 30%,而成本却占总成本的 15% 40%,因此密封设计工作是高压容器设计的重要组成部分。由于许多超高压设备为间隙操作 ,操作时不但要求物料能快装快卸 ,且要求在开启频繁的情况下仍能实现多次可靠密封 ,一般使用快开式自紧密封结构才能解决这一难题。普通 O形橡胶密封环具有结构简单、制造方便、价格便宜、安装紧凑、使用方便和具有自紧密封作用等优点 ,被各行业广泛使用。因此实验采用丁腈橡胶 (NBR)O形环 (规格为 32.53.55G,执行标准为 GB3452.1 92)进行角密封实验研究。 O形环的自紧密封原理 1)预紧状态 O形环装入密封部位后 ,其截面一般受到一定量的压缩 ,由于 O形环有良好的弹性 , 6 对接触面会产生一定的接触压力 ,从而实现预紧状态下的密封。 2)工作状态 当密封腔充入液压介质后 ,在介质压力的作用下 ,O形环移向低压一侧 ,封闭住密封间隙。随着介质压力的增加 ,接触压力亦随之增加 ,其峰值总是大于流体介质压力。这就保证了 O形密封环的密封功能 ,也反映了 O形密封环的自动密封能力。经验表明 ,对于普通橡胶材料 ,一般以 13105Pa为标准比压。 2主要密封参数的确 定 O形环的密封效果与压缩率、截面直径、密封间隙、橡胶硬度、密封面的粗糙度和密封件的形位公差等因素密切相关。在影响 O形环密封性能的诸因素中 ,只要有 1个参数的设计不合理就会降低其密封效果 ,甚至导致密封失效。因此下面就讨论一下各影响因素具体数值的确定。 1)压缩率 形环密封是典型的压缩型密封。 O形环截面直径的压缩率是影响密封效果和使用寿命的重要参数。大多数情况下的泄漏与压缩量不足有关 ,但是过量压缩又会造成装拆困难和产生过大的残余变形 ,而这将严重缩短其使用寿命。因此应合理确定形环的压缩率。压缩率用下式表示 :W=d0/hd0100%式中 d0为 O形环的截面直径 (mm),h为 O形环压缩后的截面尺寸。对于静密封压缩率一般取 10% 22%,本实验取为 15%。 2)截面直径 对于相同的压缩量 ,截面直径大的 O形环的接触宽度大 ,相应的最大接触应力小 ,因此在橡胶 O形环满足结构工艺等其他要求的情况下 ,尽可能选择大截面的橡胶 O形环。本实验容器密封面内孔直径为 39mm,O形环截面直径取 3.55mm。 3)密封间隙 O形环在高压力下很容易变形 ,容易被挤入密封间隙中去 ,造成损坏 ,因此必须对 O形环的密封间隙加以严格控制。为了防止 O形环发生 挤出现象 ,并考虑到装拆的难易程度 ,本实