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THE HONGKONG GOVERNMENT GAZETTE, MARCH 16, 1906.
The water-bath or beating vessel is so constructed that, when the oil-cup is placed in position in it, an air-space or air-chamber intervenes between the two; consequently, in applying the test under ordinary circum- stances, the heat is transmitted gradually to the oil from the hot water through the air-space. The water-bath is fitted with a socket for receiving a long bulb thermometer, to indicate the temperture of the water. It is also provided with a funnel, an over-flow-pipe, and two handles.
The water-bath rests upon a tripod stand, which is fitted with a copper cylinder or jacket, so that the bathi is surrounded by an enclosed air-space, which retains and regulates the heat. One of the legs of the stand serves as a support for a spirit lamp, which is attached to it by a small swing bracket.
The clockwork arrangement, by which during the operation of testing the slide is withdrawn, and the test- flame dipped into the cup and raised again as the slide is replaced, is provided with a ratchet key for setting it in action for each test, and with a trigger for starting it each time that the test-flame is applied.
DIRECTIONS FOR PREPARING THE SAMPLE FOR TESTING.
PREPARING THE SAMPLE FOR TESTING.-About ten fluid ounces of the oil, sufficient for three tests, arc transferred from the bottle into which the sample has been drawn to a pint flask or bottle, which is to be immersed in water artificially cooled until a thermometer, introduced into the oil, indicates a temperature not exceeding 50° Fahrenheit.
DIRECTIONS FOR PREPARING AND USING THE TEST APPARATUS,
1. PREPARING THE WATER-BATH.-The water-bath is filled by pouring water into the funnel until it begins to flow out at the overflow-pipe. The temperature of the water at the commencement of each test, as indicated by the long bulb thermometer, is to be 130° Fahrenheit and this is attained in the first instance by mixing hot and cold water, either in the bath or in a vessel from which the bath is filled, until the thermometer which is provided for testing the temperature of the water gives the proper indication; or the water is heated by means of the spirit-lamp (which is attached to the stand of the apparatus) until the required temperature is
indicated.
2. PREPARING THE TEST-LAMP.-The fest-lamp is fitted with a piece of cylindrical wick of such thick- ness that it fills the wick-holder, but may readily be moved to and fro for the purpose of adjusting the size of the flame. In the body of the lamp, upon the wick, which is coiled within it, is placed a small tuft of cotton wool moistened with petroleum, any oil not absorbed by the wool being removed. When the lamp has been lighted, the wick is adjusted by means of a pair of forceps, or a più, until the flame is of the size of the bead fixed on the cover of the oil-cup; should a particular test ocenpy so long a time that the flame begins to get smaller, through the supply of oil in the lamp becoming exhausted, three or four drops of petroleum are allowed to fall upon the tuft of wool in the lamp from the dropping bottle cr pipette provided for that purpose. can be safely done without interrupting the test.
This
3. FILLING THE On-Cur.—Before the oil-cup is filled, the lid is to be made ready for being placed upon the cup, ie, the round bulb thermometer is to be inserted into the socket (so that the projecting rim of the collar with which it is fitted touches the edge of the socket), and the test-lamp is to be placed in position. The oil-cup, having been previously cooled by placing it bottom downwards in water at a temperature not exceeding 50° Fahrenheit, is now to be rapidly wiped dry, placed on a level surface in a good light, and the oil to be tested is poured in, without splashing, until its surface is level with the point of the gauge which is fitted in the cup. The lid is then put on the cup at once, and pressed down so that its edge rests on the rim of the eup.
4. ÅPPLICATION OF THE TEST.--The water-bath, with its thermometer in position, is placed in some locality where it is not exposed to currents of air, and where the light is sufficiently subdued to admit of the size of the entire test-flame being compared with that of the bead on the cover. The cup is carefully lifted, without shaking it, and placed in the bath, the test-lamp is lighted, and the clockwork wound up by turning the key. The thermometer in the oil-cup is now watched, and when the temperature has reached 56° Fahren- heit the clockwork is set in motion by pressing the trigger,
If no flash takes place the glockwork is at once re-wound, and the trigger pressed at 57° Fahrenheit, and so on, at every degree rise of temperature, until the flash occurs, or until a temperature of 95° Fahrenheit has been reached.
If the flash takes place at any temperature below 77° Fahrenheit the temperature at. which it occurs is to be recorded. The fresh portions of the sample are then to be successively tested in a similar manner and the results recorded. If no greater difference than 2 Fahrenheit exists between any two of the three recorded results, each result is to be corrected for atmospheric pressure, as hereafter described, and the average of the three corrected results is the flashing point of the sample. In the event of there being a greater difference than 2° Fahrenheit between any two of the results, the series of tests is to be rejected and a fresh series of three similarly obtained, and so on until a sufficiently concordant series is furnished, when the results are to be cor- rected and the average taken in the manner already described.
No flash which takes place within eight degrees of the temperature at which the testing is commenced shall be accepted as the true flashing point of the sample tested. In the event of a flash occurring at or below 64° when the test is applied in the manner above described, the next testing shall be commenced ten degrees lower than the temperature at which the flash had been previously obtained (that is to say, at 54° or thereunder) and this procedure shall be continued until the results of three consecutive tests do not show a greater difference
than 2.
If a temperature of 76° Fahrenheit has been reached without a flush occurring, the application of the test- flame is to be continued at every degree rise of temperature until a temperature of 95° Fahrenheit has been reached. If no flash has occurred up to this point, the tests shall not be continued, and the testing officer shall eertify that the petroleum has a flashing point of over 95o. But if the petroleum is petroleum tar or petroleum fuel, and is declared to have its flashing point at or above 150°, the test shall be continned as follows:-The oil-cup is to be removed from the water-bath, and the temperature of the water in the water-bath is to be reduced to 95° Fahrenheit by pouring cold water into the funnel (the hot water escaping by the overflow-pipe). The air-chamber is then to be filled to a depth of 11⁄2 inches with water at a temperature of about 95° Fahrenheit, the oil-cup is to be replaced in the water-bath, and the spirit-lamp, attached to the water-bath, is to be lighted and placed underneath. The test-flame is then to be again applied, from 96° Fahrenheit, at every degree rise of temperature as indicated by the thermometer in the oil-cup until a flash takes place, or until a temperature of 150° Fahrenheit has been reached. If during this operation the test-flame appears to diminish in size, the lamp is to be replenished in the manner prescribed (at 2) without interrupting the test.