Physical Chemistry. But which expression is correct, and what exactly does it mean? The correct phrase is moot point. Nearby words flash method , flash mob , flash photography , flash photolysis , flash picture , flash point , flash set , flash smelting , flash spectrum , flash unit , flash welding. Origin of flash point First recorded in — Examples from the Web for flash point They reached the flash-point of action at almost an identical moment. The Life of Florence Nightingale vol.
The boiling off of the water can give a false positive on fuel for instance. Water can also snuff out the flame in cases where a gas pilot flame is used. One solution to dealing with water is to add particles of calcium sulfates or calcium carbonate prior to performing the flash. Centrifuging is yet another solution.
It has also been reported that coal dust and glycol antifreeze can synthesize volatile oil components resulting in an up-tick in flash point. Flash points also vary somewhat within viscosity grades as influenced by the crude oil type and refining process. As previously mentioned, synthetic lubricants typically exhibit higher flash points than their mineral-oil counterparts. Therefore, it is sometimes possible to detect a wrong or mixed oil with the use of flash point testing. However, from a practical standpoint, other routine tests such as infrared spectroscopy, TAN, viscosity and color are more effective in alerting users to wrong or mixed lubricants.
In these instances, the flash point test better serves in a confirming role. A lubricant subjected to high operating temperatures over a long period of time might lose a considerable portion of its light ends from evaporation. Additionally, it is possible that the routine use of vacuum dehydrators at high inlet temperatures can cause evaporation of certain additives and low-boiling point base oil fractions. In order to insure accurate flash point results it is important that a representative sample be presented to the instrument.
For various reasons, this is easier said than done. It is worth noting that the precautions here are equally true for any test FTIR , gas chromatography, etc. Many fuels, for instance, will evaporate from the oil over time if the sample is not properly sealed. And, light fuel fractions can literally diffuse through the walls of certain sample containers such as those made of polyethylene and polypropylene.
In such cases, PET plastic and glass bottles are preferred.
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There may also be loss of light fuel fractions when vacuum sampling pumps are used to pull hot engine oils from crankcases. The vacuum generated not only draws the oil but can sharply reduce the boiling point of the fuel, leading to its evaporation. For this and other important reasons, the preferred sampling location for crankcase oils is on the pressure line between the pump and the filter using an acceptable live-zone sampling procedure.
Caution needs to be taken by the laboratory as well.
Samples should not be left uncapped, subjected to vacuum, or heated prior to flash point testing or any test for fuel dilution. There are many detailed procedures and guidelines included in the ASTM flash point standards that should be observed to insure quality and test accuracy.
In order to insure accuracy and quality it is best to follow standardized flash point procedures and instrument configurations. However, only three are commonly used for lubricants and hydraulic fluids. And, because of the differences in these procedures, a flash point temperature must be always quoted specific to the procedure employed.
A brief description of the three flash point procedures follows see also Figure 6 :. This test procedure utilizes an open metal container that is filled with the sample oil. The oil is then heated at a prescribed rate and periodically a small pilot flame ignitor is passed over its surface.
This continues until a flash appears. The oil temperature is then recorded as its flash point. In the used oil analysis lab however, the procedure can require more oil than typically available and an exceedingly long test time. And, for fuel dilution the lower limit of sensitivity may be inadequate because, being open, it does not retain the vapors long enough to get a flash.
With this test, the sample is confined in a closed container into which the pilot flame is periodically introduced. Additionally, the lubricant is agitated during the heating period and the lowest temperature at which a flash appears is recorded. As with the COC method, a considerable amount of fluid and time is needed to perform the test.
However, fully automated instruments are available from various suppliers. In measuring fuel dilution, one advantage the Pensky-Marten has over the COC method is improved sensitivity to lower concentrations of fuel dilution Figure 7. This small-scale flash point tester goes by various names e.
The finite flash point can also be obtained Method B but more fluid and time are needed. It is also worth noting that both the repeatability and reproducibility of this procedure is distinctly better than the previous two tests Figure 8. The flash point has endured the test of time.
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In many applications of used oil analysis the flash point test remains the method of choice in detecting certain contaminants and non-conforming lubricant conditions. In other cases the flash point serves as a dependable diagnostic tool or confirming test when a suspect condition has already been flagged.
Using Flash Point to Detect and Quantify Fuel Dilution
And, like most everything in the world of oil analysis , success in using the flash point depends on the careful adherence to such things as sample handling and test protocol. Shublein, R. Toggle navigation Toggle search. Magazine Subscribe Today! Current Issue Archive Advertise. What is an Oil's Flash Point?
Flash Point | Definition of Flash Point by Merriam-Webster
Using Flash Point to Detect and Quantify Fuel Dilution Originally, the flash point was developed for the purpose of determining the fire hazard of fuels and oils being stored or transported. Other Applications For Flash Point Testing in Used Oil Analysis It is not common for labs to employ flash point testing in applications outside of used engine oil analysis. Below is a list of applications for flash point testing other than fuel dilution : Base Oil Cracking Occasionally, very high, localized temperatures can lead to cleavage and gas evolution within the oil, lowering the flash point.
Contamination Because the flash point is sensitive to low-boiling point constituents within the oil a change in flash point up or down might indicate the presence of an uninvited guest, i. Subtractions From the Oil A lubricant subjected to high operating temperatures over a long period of time might lose a considerable portion of its light ends from evaporation. Sampling and Sample Handling In order to insure accurate flash point results it is important that a representative sample be presented to the instrument. Standarized Flash Point Tests for Lubricants In order to insure accuracy and quality it is best to follow standardized flash point procedures and instrument configurations.
A brief description of the three flash point procedures follows see also Figure 6 : Cleveland Open Cup COC This test procedure utilizes an open metal container that is filled with the sample oil. Pensky-Marten Closed Cup With this test, the sample is confined in a closed container into which the pilot flame is periodically introduced.
Small Scale Closed Tester This small-scale flash point tester goes by various names e. Conclusions The flash point has endured the test of time. Lippincott Company, Caines, A. Snook, Willett A. Texaco Publication Moller, U. Jim Fitch. Jim Fitch, a founder and CEO of Noria Corporation , has a wealth of experience in lubrication, oil analysis, and machinery failure investigations.
He has advise Read More.
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