EVERYTHING ABOUT LUBRICANTS EXPLAINED !!

Lubricant is substance that reduces friction and wear at the interface of two materials. Or we can say that a lubricant is a substance introduced to reduce frictional force and heat generation between the surfaces in mutual contact, when the surfaces move. The lubricant at interface reduces the adhesive friction by lower the shear strength of interface. 

Based on the shear strength of lubricant or molecular state, lubricants are classified in four categories.

• Gaseous lubricants
• Liquid lubricants
• Semi-solid lubricants
• Solid lubricants

  Gaseous lubricants:-

Gas(i.e, Air, Nitrogen, and Helium) lubrication is used for ultra thin film thickness(separation) between tribo-pairs. Gas lubricated bearings have numerous advantanges over liquid and solid lubricated bearings for a wide range of applications.   A gas bearing is virtually frictionless, silent, and vibrationfree.   Gas bearings can be used for extremely large surface velocities.   A gas bearing can eliminate the risk of contaminating a process with lubricant.  A gas / air bearing can be hydrodynamic or hydrostatic.  In hydrodynamic bearings the gas is introduced into the bearing surfaces by the action of the bearing.  In hydrostatic bearing the gas is introduced under pressure from an external source.Air bearings are also widely used to allow frictionless movement of large heavy items over flat surfaces using air pads. Liquid lubricants:- There are two systems for oil classification. The SAE (Society of Automotive Engineers) viscosity grade and the API (American Petroleum Institute) classification that designates the type of engines for which the oil was designed. The SAE viscosity grade is known as the “W” number when classifying winter oils. In general, the lower the first number, the better the oil performance in extremely cold conditions. Conversely, the higher the second number the better the oil protection at higher temperatures. The API designation is typically “S” designation for gasoline engines and a “C” designation for diesel engines. Most of today’s oils carry an SH,CF or SJ,CF designation signifying that they are suitable for use in all gasoline or diesel automotive applications. Semi-solid lubricants(Grease):- In layman’s language Grease is: A black or yellow sticky mass used in the bearings for lubrication purpose. Lubricating greases consist of lubricating oils, often of quite low viscosity, which have been thickened by means of finely dispersed solids called thickeners. It consist of base oils(75 to 95%), additives(0 to 5%) and minute thickener fibers(5 to 20%). Solid lubricants:- A solid lubricant is basically any solid material which can be placed between two bearing surfaces and which will shear more easily under a given load than the bearing materials themselves. The coefficient of friction in dry lubrication is related to the shearing force and the bearing load.One way to apply solid lubricant is powder coating. We can use powder form of solid lubricant and rub against the tribo surfaces.Examples are Graphite and molybdenum disulfide (MoS2),Graphite etc. A good lubricating oil generally possess the following characteristics: Suitable Viscosity: The viscosity of oil should not change with rise in temperature. Oilness: It ensures the adherence to the bearings and spread over the surface. This property makes oil smooth and very important in boundary lubrication. Strength: The lubricant must have high strength to avoid metal contact and seizure under heavy loads. Chemical Stability: The lubricant should not react with surfaces and any deposit in the cylinder. Pour Point: It should be low to allow the flow of lubricant at low temperature to the oil pump. Flash Point and Fire Point: The lubricating oil should not burn inside the cylinder, otherwise it will leave heavy deposit and poisonous exhaust. Therefore, the flash point and fire point of the lubricating oil must be high. Neutralization: The oil should not have a tendency to form deposits by reacting with air, water, fuel or the products of combustion. Cleaning: The oil should act as cleaning agent inside the engine and should carry any deposits with it. It should also have non-foaming characteristics, low cost and be non-toxic.

KNOW WHY UPSIDE DOWN SUSPENSION IS USED IN HIGH END MOTORBIKES !!

A lot of bikes today are getting upside down suspension setups on the front while the others are getting the regular telescopic suspension.For example,KTM is using them as a default.

Here are top reasons,what makes them so special :

1.)In case of regular telescopic suspension system,hollow tube or damping unit is laden on to the wheel. This ends up with the entire weight of the shock system on to the wheel which kind of makes the movement of the wheel and the handle a lot stiffer.Thus,with upside down suspension handling is improved.

2.)Now the reason why only the performance bikes are provided with upside down forks is for this reason. The bikes generally travel at very high speeds, and that means the steering of the bike needs to be as agile as possible.So,less weight on the wheels help in better steering.

3.)More rigid- In a conventional fork the narrower stanchion is fixed to the frame, but in a upside down suspension fork the larger diameter slider is fixed this makes the forks more rigid and improves feel.

So all in all, if you plan to run your bike(at higher speeds) on the highways most of the times which are in somewhat good shape, then yes you can opt for upside down forks, but for someone who has the running within city limits and broken roads, then please put in conventional telescopic suspension on as it will provide better protection to the bike.

CHECK OUT WHY AIR CONDITIONER IS MEASURED IN "TONS" !!

Why is air conditioner capacity measured in tons? You may have wondered this, especially since you know your 1.5-ton capacity air conditioner doesn’t actually weigh 1.5 tons. Here’s what that 1.5 ton designation really means and why air conditioner capacity is measured this way.

We know that the air conditioner’s number of tons doesn’t refer to its weight. In fact, this number refers to the amount of heat the air conditioner can remove from a house within one hour. For example, a 4-ton air conditioner is able to remove 48,000 British thermal units (or BTUs) from the house per hour. One BTU is roughly equivalent to the heat that would be produced if you lit one match and burnt it all the way. One ton of A/C capacity is equivalent to 12,000 BTU per hour.

Now we know what a ton means, but we still haven’t answered the question of why the ton is the unit of measure for air conditioner capacity. Before the invention of the air conditioner, people who could afford it used large blocks of ice to cool their homes in the summer and refrigerate food. The ice was harvested during the winter from frozen lakes and rivers.

But how did the use of ice to cool buildings lead to the term “ton”? Basically, it takes 143 BTUs to melt a one-pound block of ice at 32 degrees. Accordingly, if you have a one-ton (2000 pound) block of ice, it takes 286,000 BTUs to melt it completely. If that block of ice melts evenly over the course of the day, it absorbs heat at the rate of 11,917 BTU/hour. Rounded up, we get 12,000 BTU/hour, or one ton of AC capacity.

Today most people know that a ton is used to measure A/C capacity, but not everyone know that the term originally referred to blocks of ice!