REFRACTOMETER KIT

with the thermometer with indicated readings that fall within the limits 20°-230°F. First, you must understand the term FLASH POINT. Flash point is the LOWEST temperature at which the fuel gives off a VAPOR that can ignite. In preparation for use, the flash-point tester (fig. 3- 9) is to be placed on a level, steady surface. If the room where the tests are to be conducted is drafty, it is good practice (but not required) to surround the tester on three sides with a shield about 18 inches wide and 24 inches high. Do not make the shield out of wood or wood products. To make the flash-point test, carry out the following steps: 1. As previously mentioned, do not test gasoline products in this machine. Thoroughly clean and dry all parts of the cup and its accessories before starting any test. Figure 3-9.—Flash-point tester and metal shield. 2. Fill the cup with the fuel to be tested up to the level indicated by the filling mark. Fuel containing free water is not to be tested since the results you would get would not be accurate. 3. Place the lid on the cup and set the cup in the stove. Take special care because the lid has locating devices so it fits only one way. 4. Insert the thermometer. It is known that JP-5 fuel has a flash point of 140°F, so use the appropriate thermometer that has the range of 20°-230°F. 5. Light the test flame and adjust it by the valve screw on the burner block, so the flame has a 5/32-inch diameter—the same size as the bad provided for comparison. 6. Plug in the unit to a 115-volt power supply. Adjust the supply of heat by adjusting the dial on the powerstat until the temperature reading increases by not more than 11°F per minute nor less than 9°F per minute. 7. Connect the stirrer to the stirrer motor. 8. Apply the test flame when the temperature of the sample is 30° to 50°F below the expected flash point of the fuel, and thereafter in multiples of 2°F. For example, if the expected flash point is 140° (JP-5), the test flame should be applied starting at 90°F, then 92°, 94°, and so forth. You apply the test flame by operating the knurled hand knob that controls the shutter and test the flame burner. The flame is lowered in one-half second, left in the lowered position for 1 second, and quickly raised to its high position. NOTE Discontinue stirring during the application of the test flame. 9. The flash point is the temperature read on the thermometer at the time of the flash. NOTE The true flash must not be confused with the bluish halo that sometimes surrounds the test flame for the applications preceding the one that causes the actual flash. REFRACTOMETER KIT The refractometer kit (fig. 3-10) is used to deter- mine the amount of fuel system icing inhibitor (FSII in jet fuels. Although it is small and made of plastic, 3-22