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 超高液壓下形環(huán)角密封的實(shí)驗(yàn)研究 摘 要 : 采用丁腈橡膠 O形環(huán)實(shí)現(xiàn)超高壓容器端部角密封 ,對容器施加超高液壓做系列密封實(shí)驗(yàn)。結(jié)果表明 ,采用角密封結(jié)構(gòu) ,并對 O形環(huán)壓縮率、截面直徑、密封間隙、橡膠硬度、密封面的粗糙度和密封件的形 位公差等相關(guān)因素進(jìn)行合理匹配 ,嚴(yán)格控制 ,使用普通 O形環(huán)可以實(shí)現(xiàn) 138MPa超高液壓的靜密封。 關(guān)鍵詞 : 超高壓 O形環(huán) 靜密封 隨著現(xiàn)代工業(yè)的快速發(fā)展 ,超高壓越來越廣泛地運(yùn)用到超高壓殺茵、超高速冷凍、食品膨化工業(yè)、超臨界流體萃取、低鹽化處理、室溫高壓膨化以及加壓發(fā)酵等典型應(yīng)用場合。這類設(shè)備所生產(chǎn)的產(chǎn)品具有眾多優(yōu)越性 ,日益 引起人們的普遍關(guān)注。如超高壓食品的生產(chǎn)具有瞬間加壓、作用均勻、操作安全和耗能低能很好地保持食物天然的色、香、味和營養(yǎng)成分的特點(diǎn) ,符合 21世紀(jì)新型食品簡便、安全、天然、營養(yǎng)、衛(wèi)生、環(huán)保的消費(fèi)需求。因而有著顯著的社會(huì)效益和經(jīng)濟(jì)效益 ,具有巨大的潛在市場和廣闊的發(fā)展前景。 但是 ,現(xiàn)今我國的超高壓食品的生產(chǎn)存在亟待提高工業(yè)裝備水平的問題 ,能否制造出經(jīng)濟(jì)、節(jié)能、安全、高效的處理設(shè)備成為制約超高壓食品處理技術(shù)市場推廣的主要瓶頸。其中 ,如何經(jīng)濟(jì)地制造超高壓容器并保證容器的超高壓密封尤為難點(diǎn)之所在。超高壓設(shè)備能否正常運(yùn)行在很 大程度上取決于密封結(jié)構(gòu)的完善性。高壓密封裝置的重量約占容器總重的 10% 30%,而成本卻占總成本的 15% 40%,因此密封設(shè)計(jì)工作是高壓容器設(shè)計(jì)的重要組成部分。由于許多超高壓設(shè)備為間隙操作 ,操作時(shí)不但要求物料能快裝快卸 ,且要求在開啟頻繁的情況下仍能實(shí)現(xiàn)多次可靠密封 ,一般使用快開式自緊密封結(jié)構(gòu)才能解決這一難題。普通 O形橡膠密封環(huán)具有結(jié)構(gòu)簡單、制造方便、價(jià)格便宜、安裝緊湊、使用方便和具有自緊密封作用等優(yōu)點(diǎn) ,被各行業(yè)廣泛使用。因此實(shí)驗(yàn)采用丁腈橡膠 (NBR)O形環(huán) (規(guī)格為 32.53.55G,執(zhí)行標(biāo)準(zhǔn)為 GB3452.1 92)進(jìn)行角密封實(shí)驗(yàn)研究。 O形環(huán)的自緊密封原理 1)預(yù)緊狀態(tài) O形環(huán)裝入密封部位后 ,其截面一般受到一定量的壓縮 ,由于 O形環(huán)有良好的彈性 , 6 對接觸面會(huì)產(chǎn)生一定的接觸壓力 ,從而實(shí)現(xiàn)預(yù)緊狀態(tài)下的密封。 2)工作狀態(tài) 當(dāng)密封腔充入液壓介質(zhì)后 ,在介質(zhì)壓力的作用下 ,O形環(huán)移向低壓一側(cè) ,封閉住密封間隙。隨著介質(zhì)壓力的增加 ,接觸壓力亦隨之增加 ,其峰值總是大于流體介質(zhì)壓力。這就保證了 O形密封環(huán)的密封功能 ,也反映了 O形密封環(huán)的自動(dòng)密封能力。經(jīng)驗(yàn)表明 ,對于普通橡膠材料 ,一般以 13105Pa為標(biāo)準(zhǔn)比壓。 2主要密封參數(shù)的確 定 O形環(huán)的密封效果與壓縮率、截面直徑、密封間隙、橡膠硬度、密封面的粗糙度和密封件的形位公差等因素密切相關(guān)。在影響 O形環(huán)密封性能的諸因素中 ,只要有 1個(gè)參數(shù)的設(shè)計(jì)不合理就會(huì)降低其密封效果 ,甚至導(dǎo)致密封失效。因此下面就討論一下各影響因素具體數(shù)值的確定。 1)壓縮率 形環(huán)密封是典型的壓縮型密封。 O形環(huán)截面直徑的壓縮率是影響密封效果和使用壽命的重要參數(shù)。大多數(shù)情況下的泄漏與壓縮量不足有關(guān) ,但是過量壓縮又會(huì)造成裝拆困難和產(chǎn)生過大的殘余變形 ,而這將嚴(yán)重縮短其使用壽命。因此應(yīng)合理確定形環(huán)的壓縮率。壓縮率用下式表示 :W=d0/hd0100%式中 d0為 O形環(huán)的截面直徑 (mm),h為 O形環(huán)壓縮后的截面尺寸。對于靜密封壓縮率一般取 10% 22%,本實(shí)驗(yàn)取為 15%。 2)截面直徑 對于相同的壓縮量 ,截面直徑大的 O形環(huán)的接觸寬度大 ,相應(yīng)的最大接觸應(yīng)力小 ,因此在橡膠 O形環(huán)滿足結(jié)構(gòu)工藝等其他要求的情況下 ,盡可能選擇大截面的橡膠 O形環(huán)。本實(shí)驗(yàn)容器密封面內(nèi)孔直徑為 39mm,O形環(huán)截面直徑取 3.55mm。 3)密封間隙 O形環(huán)在高壓力下很容易變形 ,容易被擠入密封間隙中去 ,造成損壞 ,因此必須對 O形環(huán)的密封間隙加以嚴(yán)格控制。為了防止 O形環(huán)發(fā)生 擠出現(xiàn)象 ,并考慮到裝拆的難易程度 ,本實(shí)