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温度对润滑剂的影响

作者: 发布时间:2018-07-16 浏览次数:334
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温度对润滑剂的影响

为什么油像鸡蛋

温度对润滑剂的状态、性能和状态有许多奇怪的影响。想想下面关于鸡蛋的一个聪明的类比:

在冰箱里放一个鸡蛋,它保持不变。

把它放在热水里,你会得到一个煮熟的鸡蛋。

在室温下放一个,你会得到一个臭鸡蛋。

把鸡蛋放在母鸡下面,你就能得到一只活小鸡。

就像生活中的许多事情一样,当涉及到润滑温度时,需要控制和节制。换句话说,如果你拥有的太少或太多,你就会遇到问题。找到温度的zui佳点,润滑油的性能和使用寿命可以延长很多倍。当然,这一切说起来很容易,但实际上却很难做到。

 

寒冷是怎么给润滑脂压力的

寒冷的冬天的早晨,我喜欢穿我的开襟羊毛衫,我总是把它放在书桌旁边的抽屉里。我需要的只是一种额外的温暖,以避开似乎穿透我办公室墙壁的极地环境。

低温也会影响我们的润滑剂。与食物或我们的鸡蛋不同,润滑剂似乎受益于低温,润滑剂可以通过化学方式降解,分离成不同的阶段,表现出不同的物理状态。让我给你举几个例子说明冷润滑剂的后果:

1,混合基础油可以开始分离成相。

2,石蜡基的基础油可以变成蜡状并形成凝胶。

3,某些添加剂会变得不溶性,导致沉淀、絮凝和沉积物的形成(如容器中的浴缸环)。

4,溶解的水可以转化为乳化水(更有害),而游离水的沉淀就会受到阻碍。

5,许多依赖热诱导化学反应的添加剂不能发挥作用(例如某些ep和aw添加剂)。

6,油会变得太粘而不能循环,油脂会变得太硬而无法供给。

7,当加厚的冷油打开安全阀时,污染物通过过滤器。

8,发动机不能转动,其他机器的运动部件可能会被锁住。

9,油环、吊环、桨叶齿轮和其他起油装置往往不能工作。

 

油和酒都不像水银那样上升

即使在润滑脂刊物上,热油也受到了更多的关注。毕竟,油不像某些上等葡萄酒,随着时间的推移会变得更好。事实上,即使是zui好的润滑脂在暴露在过多的热量下也会产生压力。例如,大多数葡萄酒的酒龄在77°f增加的速度是55°f时的两倍快,这当然是为什么鉴赏家和收藏家喜欢用酒窖温度存储他们的流动资产。

1903年,斯万特·阿伦尼乌斯(svante arrhenius)在计算出温度和大多数化学反应速率之间的关系时,获得了诺贝尔奖。通常被称为阿伦尼乌斯率规则,它指出润滑剂的温度一旦超过了基础活化温度, 温度每增加10°c(18°f),降解(氧化)的速度将翻倍。

事实上,热量过多会带来一系列问题。让我们开始另一个关于高温后果的列表:

1,加速添加剂和基础油的分解。,

2,有些添加剂会挥发并逸入大气。

3,vi改进剂的剪切速度更快。

4,微生物污染物喜欢更温暖的温度(而不是滚烫)。

5,热使油膜坍缩,导致加速磨损和变形。

6,热油缩短了过滤器和密封的寿命,加速了腐蚀。

7,油和油脂都更容易泄漏。

8,润滑脂在高温下更快分离(油和增稠剂分离)。

9,高温的表面可以形成碳质胶和树脂。

 

油的温度

下表说明了热润滑图表的使用。现在大多数计算机上都有这样的软件。它们可以被打印出来并层压在受动态温度变化影响的机器上。

 

1531709436.gif

 

当然,温度在机器状态监测中起着重要的作用,这也是为什么现在大多数pdm工具箱里都有热枪。就像我们需要测量体温一样来判断我们是否在发烧,大多数润滑、摩擦和磨损的问题都会有温度曲线或特征。所以在这个意义上,温度变化是好的。

从整体上看,整个温度问题绝对不是一件小事,所以要把温度计放在手边。

 

为关键设备开发热润滑图

为关键设备制定热润滑图。为要监视的机器上的特定位置(例如,供应线)定义温度点a到f。

正常工作范围(3区)由温度点c和d组成。c以下的温度变化由加热器和报警器控制。d以上的温度变化由冷却器和警报控制。

在区域2和/或4的持续操作减少了机器和/或润滑剂的使用寿命。例如,在2区运行可能会阻碍润滑油流向轴承,增加能量消耗,增加发泡倾向。4区操作可加速油氧化,降低膜强度,增加与颗粒相关的磨损。

在第1和/或5区操作会威胁机器的可靠性。温度点a和f是突然死亡的极端值。1区为典型的局部润滑油饥饿状态,5区为火灾危险、热氧化油降解、添加剂消耗、挥发和高摩擦磨损状态。

使用高vi润滑剂有助于通过c降低a点的温度。使用高vi和高 级合成润滑剂有助于通过f提高d点的温度。

 





 

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.

1531706228.png

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.

1531709436.gif

 

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.

 

洛阳申雨钼业坐落于中国钼都栾川,依托优质资源和先进的生产工艺,我司致力于为客户提供质量稳定可靠的二硫化钼粉末及其下游产品,并致力于成长为润滑工程凯发官网入口的解决方案提供商。

 


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