為什么油像雞蛋

溫度對(duì)潤(rùn)滑劑的狀態(tài)、性能和狀態(tài)有許多奇怪的影響。想想下面關(guān)于雞蛋的一個(gè)聰明的類比:

在冰箱里放一個(gè)雞蛋，它保持不變。

把它放在熱水里，你會(huì)得到一個(gè)煮熟的雞蛋。

在室溫下放一個(gè)，你會(huì)得到一個(gè)臭雞蛋。

把雞蛋放在母雞下面，你就能得到一只活小雞。

就像生活中的許多事情一樣，當(dāng)涉及到潤(rùn)滑溫度時(shí)，需要控制和節(jié)制。換句話說，如果你擁有的太少或太多，你就會(huì)遇到問題。找到溫度的zui佳點(diǎn)，潤(rùn)滑油的性能和使用壽命可以延長(zhǎng)很多倍。當(dāng)然，這一切說起來很容易，但實(shí)際上卻很難做到。

寒冷是怎么給潤(rùn)滑脂壓力的

寒冷的冬天的早晨，我喜歡穿我的開襟羊毛衫，我總是把它放在書桌旁邊的抽屜里。我需要的只是一種額外的溫暖，以避開似乎穿透我辦公室墻壁的極地環(huán)境。

低溫也會(huì)影響我們的潤(rùn)滑劑。與食物或我們的雞蛋不同，潤(rùn)滑劑似乎受益于低溫，潤(rùn)滑劑可以通過化學(xué)方式降解，分離成不同的階段，表現(xiàn)出不同的物理狀態(tài)。讓我給你舉幾個(gè)例子說明冷潤(rùn)滑劑的后果:

1，混合基礎(chǔ)油可以開始分離成相。

2，石蠟基的基礎(chǔ)油可以變成蠟狀并形成凝膠。

3，某些添加劑會(huì)變得不溶性，導(dǎo)致沉淀、絮凝和沉積物的形成(如容器中的浴缸環(huán))。

4，溶解的水可以轉(zhuǎn)化為乳化水(更有害)，而游離水的沉淀就會(huì)受到阻礙。

5，許多依賴熱誘導(dǎo)化學(xué)反應(yīng)的添加劑不能發(fā)揮作用(例如某些EP和AW添加劑)。

6，油會(huì)變得太粘而不能循環(huán)，油脂會(huì)變得太硬而無法供給。

7，當(dāng)加厚的冷油打開安全閥時(shí)，污染物通過過濾器。

8，發(fā)動(dòng)機(jī)不能轉(zhuǎn)動(dòng)，其他機(jī)器的運(yùn)動(dòng)部件可能會(huì)被鎖住。

9，油環(huán)、吊環(huán)、槳葉齒輪和其他起油裝置往往不能工作。

油和酒都不像水銀那樣上升

即使在潤(rùn)滑脂刊物上，熱油也受到了更多的關(guān)注。畢竟，油不像某些上等葡萄酒，隨著時(shí)間的推移會(huì)變得更好。事實(shí)上，即使是zui好的潤(rùn)滑脂在暴露在過多的熱量下也會(huì)產(chǎn)生壓力。例如,大多數(shù)葡萄酒的酒齡在77°F增加的速度是55°F時(shí)的兩倍快,這當(dāng)然是為什么鑒賞家和收藏家喜歡用酒窖溫度存儲(chǔ)他們的流動(dòng)資產(chǎn)。

1903年，斯萬特·阿倫尼烏斯(Svante Arrhenius)在計(jì)算出溫度和大多數(shù)化學(xué)反應(yīng)速率之間的關(guān)系時(shí)，獲得了諾貝爾獎(jiǎng)。通常被稱為阿倫尼烏斯率規(guī)則,它指出潤(rùn)滑劑的溫度一旦超過了基礎(chǔ)活化溫度, 溫度每增加10°C(18°F)，降解（氧化）的速度將翻倍。

事實(shí)上，熱量過多會(huì)帶來一系列問題。讓我們開始另一個(gè)關(guān)于高溫后果的列表:

1，加速添加劑和基礎(chǔ)油的分解。,

2，有些添加劑會(huì)揮發(fā)并逸入大氣。

3，VI改進(jìn)劑的剪切速度更快。

4，微生物污染物喜歡更溫暖的溫度(而不是滾燙)。

5，熱使油膜坍縮，導(dǎo)致加速磨損和變形。

6，熱油縮短了過濾器和密封的壽命，加速了腐蝕。

7，油和油脂都更容易泄漏。

8，潤(rùn)滑脂在高溫下更快分離(油和增稠劑分離)。

9，高溫的表面可以形成碳質(zhì)膠和樹脂。

油的溫度

下表說明了熱潤(rùn)滑圖表的使用。現(xiàn)在大多數(shù)計(jì)算機(jī)上都有這樣的軟件。它們可以被打印出來并層壓在受動(dòng)態(tài)溫度變化影響的機(jī)器上。

當(dāng)然，溫度在機(jī)器狀態(tài)監(jiān)測(cè)中起著重要的作用，這也是為什么現(xiàn)在大多數(shù)PdM工具箱里都有熱槍。就像我們需要測(cè)量體溫一樣來判斷我們是否在發(fā)燒，大多數(shù)潤(rùn)滑、摩擦和磨損的問題都會(huì)有溫度曲線或特征。所以在這個(gè)意義上，溫度變化是好的。

從整體上看，整個(gè)溫度問題絕對(duì)不是一件小事，所以要把溫度計(jì)放在手邊。

為關(guān)鍵設(shè)備開發(fā)熱潤(rùn)滑圖

為關(guān)鍵設(shè)備制定熱潤(rùn)滑圖。為要監(jiān)視的機(jī)器上的特定位置(例如，供應(yīng)線)定義溫度點(diǎn)A到F。

正常工作范圍(3區(qū))由溫度點(diǎn)C和d組成。C以下的溫度變化由加熱器和報(bào)警器控制。D以上的溫度變化由冷卻器和警報(bào)控制。

在區(qū)域2和/或4的持續(xù)操作減少了機(jī)器和/或潤(rùn)滑劑的使用壽命。例如，在2區(qū)運(yùn)行可能會(huì)阻礙潤(rùn)滑油流向軸承，增加能量消耗，增加發(fā)泡傾向。4區(qū)操作可加速油氧化，降低膜強(qiáng)度，增加與顆粒相關(guān)的磨損。

在第1和/或5區(qū)操作會(huì)威脅機(jī)器的可靠性。溫度點(diǎn)A和F是突然死亡的極端值。1區(qū)為典型的局部潤(rùn)滑油饑餓狀態(tài)，5區(qū)為火災(zāi)危險(xiǎn)、熱氧化油降解、添加劑消耗、揮發(fā)和高摩擦磨損狀態(tài)。

使用高VI潤(rùn)滑劑有助于通過c降低A點(diǎn)的溫度。使用高VI和高 級(jí)合成潤(rùn)滑劑有助于通過F提高D點(diǎn)的溫度。

The Effects of Temperature on Lubricants

Why Oil is Like an Egg

Jim Fitch, Noria Corporation

Tags: industrial lubricants

Temperature has many strange effects on lubricant states, performance and condition. Consider the following clever analogy about an egg:

Put an egg in the refrigerator and it remains unchanged.

Place it in very hot water and you get a hard-boiled egg.

Leave one out at room temperature and you get a rotten egg.

Put an egg under a mother hen and you get a live chick.

Like many things in life, when it comes to lubricant temperature, there's a need for control and moderation. In other words, you can expect problems if you have too little or too much. Find the temperature sweet spot and the performance and service life of your lubricant can be extended manyfold. Of course it's all so easy to say, but in practice can be oh so difficult to do.

How Cold Stresses Lubricants

On a cold winter morning like today, I like to wear my cardigan, which I always keep in a drawer next to my desk. It's just the added warmth I need to stave off the polar conditions that seem to penetrate my office walls.

Cold temperature can stress our lubricants as well. Unlike food, or our egg, which seems to benefit from cold temperatures, lubricants can chemically degrade, separate into phases and exhibit altered physical states. Let me give you a few examples of the consequences of cold lubricants:

l  Blended base oils can begin to separate into phases.

l  Paraffinic basestocks can become waxy and form gels.

l  Certain additives can become insoluble, resulting in settling, flocculation and formation of deposits (such as bathtub rings in tanks).

l  Dissolved water can transition to emulsified water (more harmful) and the settling of free water becomes impeded.

l  Many additives that depend on heat-induced chemical reactions fail to perform (certain EP and AW additives, for instance).

l  Oil can become too viscous to circulate and grease too stiff to feed.

l  Contaminants by-pass filters as thickened cold oil opens relief valves.

l  Engines won't crank and moving parts in other machines may become locked up.

l  Oil rings, slingers, paddle gears and other oil-lifting devices will often fail to work.

Neither Oil nor Wine Like the Mercury to Rise

Hot oil has gotten the most press, even in this publication. After all, oil is not like some fine wines that get better over time. In fact, even the very best Boudreaux will stress-out when exposed to too much heat. For instance, most wines will age roughly twice as fast at 77°F compared to 55°F, which of course is why connoisseurs and collectors prefer cellar temperature to store their liquid assets.

In 1903, Svante Arrhenius won a Nobel Prize when he figured out the relationship between temperature and most chemical reaction rates. Often called the Arrhenius Rate Rule, it relates to the fact that lubricants, once they've exceeded their base activation temperature, will degrade (oxidize) twice as fast for every 10°C (18°F) increase in temperature.

In fact, there are a range of problems associated with too much heat. Let's start another list on the consequences of high temperature:

l  Accelerates additive and base oil decomposition (Arrhenius).

l  Some additives will volatilize and escape into the atmosphere.

l  VI improvers shear down more rapidly.

l  Microbial contaminants prefer warmer temperatures (but not scalding).

l  Heat collapses oil films, causing accelerated abrasion and scuffing conditions.

l  Hot oil shortens the life of filters and seals and accelerates corrosion.

l  Both oil and grease are more prone to leakage.

l  Grease separates fasters (oil from thickener) at elevated temperatures.

l  High surface temperatures can form carbonaceous gum and resins.

Taking Your Oil's Temperature

The table below illustrates the use of thermal lubrication charts. These can be easily designed with software found on most computers today. They can be printed and laminated for posting on those machines exposed to dynamic temperature changes.

Of course, temperature plays a vital role in machine condition monitoring which is why heat guns are found in most PdM tool boxes these days. Just like we need to take our temperature to know if we are running a fever, most problems with lubrication, friction and wear will have a temperature profile or signature. So in that sense, temperature change is good.

When viewed together, the entire subject of temperature is definitely no trivial matter… so keep that thermometer handy.

Develop Thermal Lubrication Charts (TLC) for Critical Machines

l  Develop thermal lubrication charts (TLC) for critical equipment. Define temperature points A through F for a specific location on the machine to be monitored (for example, supply line).

l  Normal working range (Zone 3) is banded by temperature points C and D. Temperature excursions below C are controlled by a heater and alarms. Temperature excursions above D are controlled by a cooler plus alarms.

l  Sustained operation in Zones 2 and/or 4 reduces the service life of the machine and/or lubricant. For instance, operating in Zone 2 may retard lubricant flow to bearings, increase energy consumption and increase foaming tendency. Operation in Zone 4 may accelerate oil oxidation, reduce film strength and increase wear associated with particles.

l  Operating in Zones 1 and/or 5 threaten machine reliability. Temperature points A and F are sudden-death extremes. Zone 1 is typically a partial lubricant starvation condition while Zone 5 is associated with fire hazard, thermal-oxidative oil degradation, additive depletion, volatilization and high-friction/wear conditions.

l  The use of high VI lubricants helps lower temperature points A through C. The use of high VI and premium formulated synthetic lubricants helps increase temperature points D through F.

洛陽申雨鉬業(yè)坐落于中國(guó)鉬都欒川，依托優(yōu)質(zhì)資源和先進(jìn)的生產(chǎn)工藝，我司致力于為客戶提供質(zhì)量穩(wěn)定可靠的二硫化鉬粉末及其下游產(chǎn)品，并致力于成長(zhǎng)為潤(rùn)滑工程解決方案提供商。