液壓油外文翻譯

1、<p><b>　　外文資料</b></p><p>　　Hydraulic Fluids</p><p>　　For long service life, safety reasons, and reliable operation of hydraulic circuits, it is very important to use the correct

2、 fluid for the application. The most common fluid is based on mineral oil, but some systems require fire resistance because of their proximity to a heat source or other fire hazard. （Water is also making its return to so

3、me hydraulic systems because it is inexpensive, fireproof, and does not harm the environment.）</p><p>　　Transmit energy.</p><p>　　The main purpose of the fluid in any system is to transmit energ

4、y. Electric, internal combustion, steam powered, or other prime movers drive a pump that sends oil through lines to valves that control actuators. The fluid in these lines must transmit the prime movers energy to the act

5、uator so it can perform work. The fluid must flow easily to reduce power losses and make the circuit respond quickly.</p><p>　　Lubricate.</p><p>　　In most hydraulic systems, the fluid must have

6、good lubrication qualities. Pumps, motors, and cylinders need ample lubrication to make them efficient and extend their service life.Mineral oils with anti-wear additives work well and are available from most suppliers.

7、Some fluids may need special considerations in component design to overcome their lack of lubricity.</p><p><b>　　Seal.</b></p><p>　　Fluid thickness can be important also because one

8、of its requirements is for sealing. Almost all pumps and many valves have metal to metal sealing fits that have minimal clearance but can leak at elevated pressures. Thin watery fluid can flow through these clearances, r

9、educing efficiency and eroding the mating surfaces. Thicker fluids keep leakage to a minimum and efficiency high.</p><p>　　There are several areas that apply to specifying fluids for a hydraulic circuit. Vis

10、cosity is the measure of the fluids thickness. Hydraulic oils thickness is specified by a SUS or SSU designation, similar to the SAE designation used for automotive fluids. SUS stands for Saybolt Universal Seconds (or as

11、 some put it, Saybolt Seconds Universal). It is a measuring system set up by a man named Saybolt. Simply stated, the system takes a sample of fluid, heats it to 100° F, and them measures how much </p><p&g

12、t;　　Viscosity is most important as it applies to pumps. Most manufacturers specify viscosity limits for their pumps and it is best to stay within the limits they suggest. The prime reason for specifying a maximum viscosi

13、ty is that pressure drop in the pump suction line typically is lowand if the oil is too thick, the pump will be damaged due to cavitation. A pump can move fluid of any viscosity if the inlet is amply supplied. On the oth

14、er end, if fluids are too thin,pump bypass wastes energy and gen</p><p>　　Viscosity index (or VI) is a measure of viscosity change from one temperature to another. It is common knowledge that heating any oil

15、 makes it thinner. A normal industrial hydraulic circuit runs at temperatures between 100° and 130° F. Cold starts could be as low as 40°to 50° F. Using an oil with a low VI number might start well bu

16、t wind up with excessive leakage and wear or cause cavitation damage at startup and run well at temperature. Mostindustrial hydraulic oils run in the 90- to 105-VI ran</p><p>　　Pour point is the lowest tempe

17、rature at which a fluid still flows. It should be at least lower than the lowest temperature to which the system will be exposed so the pump can always have some lubrication. Consider installing a reservoir heater and a

18、circulation loop on circuits that start or operate below 60° F.</p><p>　　Refined mineral oil does not have enough lubricating qualities to meet the needs of modern day hydraulic systems. Several lubrici

19、ty additives to enhance that property are added to mineral oil as a specific manufacturers package. These additives are formulated to work together and should not be mixed with others additives because some components ma

20、y be incompatible.</p><p>　　Refined mineral oil also is very much affected by temperature change. In its raw state it not only has low lubricity but also would thin out noticeably with only a small increase

21、in temperature. Viscosity modifiers enhance the oils ability to remain at a workable viscosity through a broad temperature range.</p><p>　　There are several causes of hydraulic oil oxidation. These include c

22、ontamination, air, and heat. The interaction of these outside influences cause sludge and acids to form. Oxidation inhibitors slow or stop the fluids degradation and allow it to perform as intended.</p><p>　

23、　Wear inhibitors are additives that bond with metal parts inside a hydraulic system and leave a thin film that reduces metal-to-metal contact. When these additives are working, they extend part life by reducing wear.<

24、/p><p>　　In most hydraulic systems, fast and turbulent fluid flow can lead to foaming. Anti-foaming agents make the fluid less likely to form bubbles and allow those that do form to dissipate more rapidly.<

25、/p><p>　　Moisture in the air can condense in a hydraulic reservoir and mix with the fluid. Rust inhibitors negate the effect of this unwanted water and protect the surfaces of the systems metal components. All

26、of these additives are necessary to extend system life and improve reliability.</p><p>　　Overheating the fluid can counteract the additives and decrease system efficiency.Overheating also thins the oil and r

27、educes efficiency because of internal bypassing. Clearances in pump and valve spools let fluid pass as pressure increases, causing more heating until thefluid breaks down. External leaks through fittings and seals also i

28、ncrease as fluid temperatures rise. Another problem caused by overheating is a breakdown of some seal materials. Most rubber compounds are cured by controlled hea</p><p>　　Cold oil is not a problem as far as

29、 the oil is concerned but cooling does increase viscosity.When viscosity gets too high, it can cause a pump to cavitate and damage itself internally.Thermostatically controlled reservoir heaters easily eliminate this pro

30、blem in most cases.</p><p>　　Fire-resistant fluids</p><p>　　Certain applications must operate near a heat source with elevated temperatures or even open flames or electrical heating units. Mine

31、ral oil is very flammable. It not only catches fire easily but will continue to burn even after removing the heat source. This fire hazard situation can be eliminated by several different choices of fluids. These fluids

32、are not fireproof, only fireresistant,which means they will burn if heated past a certain temperature but they will not continue to burn after rem</p><p>　　Generally, the fire-resistant fluids do not have th

33、e same specifications as mineral oil-based fluids. Pumps often must be down rated because the fluids lubricity or specific gravity is different and would shorten the pumps service life drastically at elevated pressures o

34、r high rotary speeds. Some fire-resistant fluids are not compatible with standard seal materials so seals must be changed. Always check with the pump manufacturer and fluid supplier before using or changing to a fire-res

35、istant fl</p><p><b>　　Water</b></p><p>　　Originally, hydraulic circuits used water to transmit energy (hence the word hydraulics). The main problem with water-filled circuits was eit

36、her low-pressure operation or very expensive pumps and valves to operate with this low viscosity fluid above 500 to 600 psi. When huge oil deposits were discovered, mineral oil replaced water because of its additional be

37、nefits. Water made a brief comeback during an oil shortage crisis but quickly succumbed when oil flowed freely again.</p><p>　　In the late 90s, water again made inroads into oil-hydraulic systems. Several co

38、mpanies have developed reliable pumps and valves for water that operate at 1500 to 2000 psi. There are still limitations (such as freezing) to using water, but in certain applications it has many benefits.One big advanta

39、ge is that there are fewer environmental problems during operation or in disposing of the fluid. Price also is a factor because water costs so little and is readily available almost anywhere.</p><p>　　Some s

40、uppliers are making equipment that operates on seawater to eliminate possible contamination of the earths potable water sources. These systems operate at elevated pressures without performance loss.</p><p>　

41、　High water-content fluids</p><p>　　Some types of manufacturing still use water as a base and add some soluble oil for lubrication.This type of fluid is known as high water-content fluid (or HWCF). The commo

42、n mixture is 95% water and 5% soluble oil. This mixture takes care of most of the lubricity problems but does not address low viscosity concerns. Therefore, systems using HWCF still need expensive pumps and valves to mak

43、e them efficient and extend their life.</p><p>　　Rolling mills and other applications with molten metals are one area where HWCF is prevalent. Often the soluble oil is the same compound used for coolant in t

44、he metal-rolling process. This eliminates concerns about cross-contamination of fluids and the problems it can cause.</p><p>　　Water-in-oil emulsions</p><p>　　Some systems use around 40% water f

45、or fire resistance and 60% oil for lubrication and viscosity considerations. Again, these are not common fluids because they require special oil and continuous maintenance to keep them mixed well and their ratio within l

46、imits. Most manufacturers do not want the problems associated with water-in-oil emulsions so their use isvery limited.</p><p><b>　　外文資料翻譯</b></p><p><b>　　液壓油</b></p>

47、;<p>　　考慮到使用壽命長(zhǎng)短，安全性的原因，以及液壓回路可靠運(yùn)行性，液壓系統(tǒng)中使用正確的液壓油這是非常重要的。最常見(jiàn)的液壓油是基質(zhì)礦物油，但有些系統(tǒng)因?yàn)榭拷鼰嵩椿蚱渌馂?zāi)隱患要求防火性能較高。（水也可以循環(huán)應(yīng)用于液壓系統(tǒng)，因?yàn)樗阋?，防火，不污染環(huán)境。）</p><p><b>　　傳輸能量</b></p><p>　　液壓油在液壓系統(tǒng)中的主要作用是

48、傳輸能量。電力、內(nèi)燃機(jī)、蒸汽動(dòng)力或其他原動(dòng)機(jī)驅(qū)動(dòng)泵，通過(guò)液壓油傳遞到控制閥門，控制執(zhí)行元件傳送能量。在這些回路傳輸能量時(shí)液壓油必然為執(zhí)行機(jī)構(gòu)的主要推動(dòng)者，因此可以執(zhí)行工作。流動(dòng)的流體必須要盡量降低功率損失，使回路迅速作出反應(yīng)。</p><p>　　潤(rùn)滑 在大多數(shù)液壓系統(tǒng)中，潤(rùn)滑液是必須得到質(zhì)量保證的。泵、馬達(dá)、液壓缸等都需要充足的潤(rùn)滑液，來(lái)提高效率和延長(zhǎng)其使用壽命。具有抗磨損添加劑的礦物油工作良好，而且銷

49、路很好。一些液壓油可能需要特殊考慮組件設(shè)計(jì)，以克服他們的潤(rùn)滑不足。</p><p>　　密封 液壓油密度也同樣十分重要，因?yàn)樗囊粋€(gè)重要性能要求是密封。幾乎所有的泵和液壓閥都是由許多金屬件組裝而成，金屬密封配合間隙很小，但有可能泄漏升高液壓系統(tǒng)的壓力損失。薄水狀液壓油可能流過(guò)這些間隙，降低效率，損壞了配合的表面。較稠的液體可將泄漏不斷的降到最低限度，提高效率。有幾種液壓油適用于指定的液壓回路流體的領(lǐng)域。粘

50、度是用于測(cè)量流體的粘稠度的，液壓油的密度是由SSU指定的，類似于SAE指定為汽車使用流體。 SUS代表（或如一些說(shuō)法，賽波特秒通用）的賽波特通用秒，這是一個(gè)由一名為賽波特的人建立的測(cè)量系統(tǒng)。簡(jiǎn)單地說(shuō)，該系統(tǒng)采用的液體樣品是加熱到100時(shí)，測(cè)量在特定時(shí)間內(nèi)有多少液體通過(guò)節(jié)流孔。</p><p>　　在液壓泵的運(yùn)用中液壓油粘度是最為重要的，大多數(shù)制造商指定的液壓油粘度極限，他們建議最好限定在這個(gè)范圍內(nèi)。指定最大粘度的

51、主要原因是，在泵的吸入管路壓降通常很低，如果液壓油太濃，泵會(huì)由于氣蝕而被損壞。</p><p>　　如果進(jìn)入油箱的氣體被充足提供，一個(gè)泵則可以帶動(dòng)任何粘度的流體。另一方面，如果液體密度太小，液壓泵則會(huì)泄漏能量從而產(chǎn)生多余的熱量?；芈分械乃衅渌M件可以在任何粘度流體運(yùn)作，因?yàn)樗麄冎挥糜诠┙o傳動(dòng)。然而，密度較大的流體會(huì)由于難帶動(dòng)而相對(duì)浪費(fèi)能源；密度較小的流體浪費(fèi)能源，是因?yàn)樗麄儞p失太多。</p>&l

52、t;p>　　粘度指數(shù)（或VI）是用于測(cè)量在不同溫度下黏度的變化的參數(shù)。任何油液加熱后密度都會(huì)變小這是常識(shí)。一個(gè)正常的工業(yè)液壓線路的運(yùn)行溫度在100至130華氏度和冷啟動(dòng)則是40至50華氏度。使用低粘度指數(shù)的液壓油運(yùn)行會(huì)很好，但是，在啟動(dòng)和運(yùn)行高速中，過(guò)多的氣體的進(jìn)入會(huì)造成氣蝕和磨損或損傷。大多數(shù)工業(yè)液壓油在90—105 VI的范圍內(nèi)運(yùn)行，并且對(duì)于大多數(shù)應(yīng)用系統(tǒng)是比較令人滿意的。</p><p>　　傾點(diǎn)是液

53、體仍可以流動(dòng)的最低的溫度。只有在比最低溫度還要低的溫度下該系統(tǒng)將暴露，因此泵就需要一些潤(rùn)滑。考慮安裝一個(gè)冷卻回路和一個(gè)加熱器回路，就可以在低于60華氏度的情況下仍可以啟動(dòng)該系統(tǒng)。 精制礦物油并不具備足夠的潤(rùn)滑油的質(zhì)量，以滿足現(xiàn)代液壓系統(tǒng)的需要。但幾種潤(rùn)滑添加劑，為了提高液壓油的品質(zhì)被添加到礦物油中，這作為具體的生產(chǎn)廠家的一攬子計(jì)劃，這些添加劑配比在一起工作，不應(yīng)與其他添加劑混合，因?yàn)槟承┙M成成分可能是不相容的。</p>

54、;<p>　　精制礦物油也經(jīng)常受溫度變化的影響。在其原始狀態(tài)下，它不僅具有較低的潤(rùn)滑性，而且隨著稍微的溫度加熱也可將密度變小。粘度調(diào)節(jié)劑提高液體的性能并保持在一個(gè)可行的粘度范圍內(nèi)。 液壓油的氧化有以下幾個(gè)原因。這些原因包括雜質(zhì)污染，空氣侵入和熱量。這些外來(lái)因素的影響是污泥和酸相互作用形成。氧化抑制劑可以阻止液體的氧化，并允許它取得預(yù)期效果。抑制劑是一種添加劑，與液壓系統(tǒng)內(nèi)的金屬部件緊密連接在一起，并留一個(gè)潤(rùn)滑薄膜，

55、減少金屬與金屬的接觸磨損。當(dāng)這些添加劑工作時(shí)，他們將減少磨損延長(zhǎng)零件壽命。</p><p>　　在大多數(shù)液壓系統(tǒng)中，液壓油的快速流動(dòng)和湍流會(huì)導(dǎo)致氣泡。防泡沫劑使流體不太可能形成泡沫，并允許那些確實(shí)形式消散更為迅速。 空氣中的水分會(huì)凝結(jié)在液壓油箱和液壓油混合。防銹劑阻止這些多余水的侵蝕作用和保護(hù)系統(tǒng)的表面金屬部件。這些添加劑都可延長(zhǎng)系統(tǒng)壽命，提高可靠性。液壓油過(guò)熱可能破損這些添加劑，降低系統(tǒng)的工作效率。溫度

56、過(guò)高也會(huì)因內(nèi)部損失太多而導(dǎo)致粘度減小，從而影響效率。 隨著壓力的加大，液壓油會(huì)流過(guò)泵中的間隙和閥芯；隨著壓力的繼續(xù)加大，該液壓油就會(huì)停止運(yùn)動(dòng)。隨著液壓油溫度的上升，通過(guò)外部配件和密封件泄漏也會(huì)增加。因過(guò)熱而造成的另一個(gè)問(wèn)題是一些密封材料破裂。在特定的時(shí)間內(nèi)，大多數(shù)橡膠化合物能被指定的熱量治愈。液壓系統(tǒng)的持續(xù)加熱會(huì)保持系統(tǒng)的正常運(yùn)轉(zhuǎn)，直到失去彈性的密封件和密封件的能力。如果液壓油在任何連續(xù)的時(shí)間內(nèi)均不會(huì)超過(guò)130華氏度這是最好的。

57、安裝冷卻器是處理過(guò)熱現(xiàn)象的最常用的方法，但設(shè)計(jì)出散熱的冷卻回路則是更好的辦法。</p><p>　　冷卻液壓油是一個(gè)是備受關(guān)注的問(wèn)題，因?yàn)槔鋮s會(huì)增加粘度，當(dāng)粘度過(guò)高，會(huì)導(dǎo)致泵被抽空和損害自身內(nèi)部。恒溫?zé)崴髟诖蠖鄶?shù)情況下容易控制從而消除這一問(wèn)題。</p><p>　　耐高溫液體 某些液壓系統(tǒng)必須在靠近高溫甚至明火或電加熱裝置的熱源的情況下才能運(yùn)行。礦物油是非常易燃的，它不僅容易著火

58、，而且即使去除熱源也會(huì)繼續(xù)燃燒，這引起火災(zāi)的危險(xiǎn)情況可以被幾種不同的液體所消除。這些液體不防火，只是耐高溫，這意味著他們?cè)诔^(guò)特定溫度的條件下燃燒，但是一旦移除了熱源，他們就不會(huì)繼續(xù)燃燒。</p><p>　　一般來(lái)說(shuō)，耐火液體沒(méi)有與礦物油基液相同的規(guī)格。由于流體或比重的不同泵通常會(huì)降低功率，并且在高壓或高旋轉(zhuǎn)速度情況下運(yùn)轉(zhuǎn)將縮短泵的使用壽命。一些耐火液體密封材料不符合標(biāo)準(zhǔn)的兼容性，故密封件必須更改。在使用或更換

59、耐高溫液體前要經(jīng)?？疾毂玫闹圃焐毯凸?yīng)商。</p><p><b>　　水</b></p><p>　　本來(lái)，液壓回路用水來(lái)傳輸能量（這里稱為水力學(xué)）。充水回路的主要問(wèn)題是只能低壓操作或高于500至600 psi的低粘度液體下，或用非常昂貴的泵和液壓閥操作。當(dāng)巨大的石油儲(chǔ)量被發(fā)現(xiàn)后，具有顯著優(yōu)點(diǎn)的礦物油取代了水。在石油短缺危機(jī)期間水又短暫復(fù)出，但是當(dāng)油價(jià)再次恢復(fù)之后，

60、水又很快就又被取代。 在90年代后期，在制造油壓系統(tǒng)迅速發(fā)展的同時(shí)水壓系統(tǒng)也取得了較高的進(jìn)展。有幾家公司已經(jīng)開(kāi)發(fā)出可靠的泵和水，在1500到2000 psi的操作閥門。水的使用還是受限制（如凍結(jié)），但在某些應(yīng)用中也受益匪淺。其中一大優(yōu)勢(shì)是，在操作過(guò)程中或在流體處理中存在著很多的環(huán)境問(wèn)題。價(jià)格也是一個(gè)因素，因?yàn)樗某杀镜?，而且是現(xiàn)成的，幾乎任何地方都可以找到。一些供應(yīng)商正在生產(chǎn)適用于海水運(yùn)行的設(shè)備，以消除對(duì)地球飲用水源的污染。這些