ABSTRACT.
The flash point of a volatile liquid is the lowest temperature at which it can vaporize to form an ignitable mixture in air. Measuring a liquid’s flashpoint requires an ignition source. This is not to be confused with the autoignition temperature, which requires no ignition source. At the flash point, the vapour may cease to burn when the source of ignition is removed. A slightly higher temperature, the fire point, is defined as the temperature at which the vapour continues to burn after being ignited. Neither of these parameters is related to the temperatures of the ignition source or of the burning liquid, which are much higher. The flash point is often used as one descriptive characteristic of liquid fuel, but it is also used to describe liquids that are not used intentionally as fuels. Flash point refers to both flammable liquids as well as combustible liquids. There are various international standards for defining each, but most agree that liquids with a flash point less than 60°C are flammable, and those above this temperature are combustible.
INTRODUCTION.
The flash point and fire point refer to the flammability characteristics of the fluid being tested. The flash point is defined as the lowest temperature at which the vapor formed above a pool of the liquid ignites in air at a pressure of 1 atmosphere. Every flammable liquid has a vapour pressure, which is a function of that liquid’s temperature. As the temperature increases, the vapour pressure increases. As the vapour pressure increases, the concentration of evaporated flammable liquid in the air increases. Hence, temperature determines the concentration of evaporated flammable liquid in the air.
Each flammable liquid requires a different concentration of its vapour in air to sustain combustion. The flash point of a flammable liquid is the lowest temperature at which there can be enough flammable vapour to ignite, when an ignition source is applied.
WORKING PRINCIPLE.
. The physical setup of the apparatus, the rate of heating, and the source of ignition are precisely defined. If the sample is in a cup exposed to the ambient air, this is referred to as the Cleveland Open Cup (COC) method. If the sample is kept closed to the ambient air until the source of ignition is applied, then this is referred to as the closed-cup method.
The fire point is the lowest temperature at which, on further heating beyond the flash point, the sample will support combustion for 5 seconds.
The flash point is an empirical measurement rather than a fundamental physical parameter. The measured value will vary with equipment and test protocol variations, including temperature ramp rate (in automated testers), time allowed for the sample to equilibrate, sample volume and whether the sample is stirred.
APPLICATION.
1. Flash & fire point pre-set, auto temperature rise.
2. Automatic remote control ignition and sweeping.
3. Temperature displaying and being stored in digital.
4. Auto ignition, Good sweeping radius.
5. less Time for test flame across the cup.
ADVANTAGES.
1. Oil refineries.
2. laboratories.
3. it can be used as a experimental set up .
DISADVANTAGES.
1. it requires external power supply.
2. initial cost is higher.
3. cannot be used for low flash point fluids like phosphors.