GB 3776.5-1983 Flash point determination method for pesticide emulsifiers (closed cup method) GB3776.5-1983 standard download decompression password: www.bzxz.net

"Scope of application
National Standard of the People's Republic of China
Method of flash point determination (closed-cup test) for pesticide emulsifiers This method is applicable to the determination of flash point of pesticide emulsifiers. 2 Instruments
2.1 Closed-cup flash point tester (see figure): SYP1002-1 closed-cup flash point tester. Issued by the National Bureau of Standards on June 15, 1983
UDC 66.063.61
GB3776.5-83
(confirmed in 1989)
implemented from 1984-06~01
GB3776.5-83
Closed-cup flash point tester
SYP1002-1 closed-cup flash point tester
1 igniter, 2-slide plate, 3-oil cup cover, 4-oil cup, 5 stirrer; 6-electric furnace, 7-motor, 8-transmission flexible shaft: 9-gas conduit, 10-ignition tube, 11-oil cup handle; 12-thermometer: 13-hand spring, 14—Small panel, 15—Oil cup holder, 16—Heater switch; 17 Agitator switch; 18—Fuse
2.2 Protective screen: Made of galvanized iron sheet. Height 550~650mm, width to suit, the inner wall of the screen is painted black. 3 Preparation
3.1 The flash point tester should be placed in a windproof and dimly lit place to facilitate observation of flash fire. If the above requirements are not met, the flash point tester can be surrounded by a protective screen.
GB3776.5--83
3.2 Wash the oil cup with anhydrous ethanol or ether, and then blow it with hot air. or let it dry naturally. 3.3 Read the atmospheric pressure P during the experiment.
4 Determination procedure
4.1 Pour the pesticide emulsifier sample into a clean and dry oil cup and fill it to the ring mark (about 70 ml). Place the oil cup in a bath jacket, cover it with a clean and dry cup lid, and insert a thermometer. 4.2 Light the gas and adjust the flame to a nearly spherical shape with a diameter of about 3 to 4 mm. 4.3 Turn on the heating and stirring device to heat and stir the sample, and control the sample temperature to rise by 1°C per minute. 4.4 When the sample temperature reaches 25°C, ignite once every 1°C increase. Test. Stop stirring during the ignition test. If no flash is seen after opening the cover for 1 second, continue stirring the sample and repeat the ignition test according to the requirements of this article. 4.5 When a blue flame first appears above the sample liquid surface, read the temperature immediately, which is the flash point. After the initial flash, continue the ignition test according to Article 4.4. The determination is considered valid only when the flash continues. 4.6 After the initial flash, if no flash is seen after ignition, the sample should be replaced for a second test. 4.7 In the second test, if the flash situation is still the same as described in Article 4.6, the test is considered to have produced a result. Take the average of the first flash temperature of the two tests as the flash point determination result. Note: ① The pesticide emulsifier sample is in a semi-solid state or has a stratified precipitation phenomenon. It should be placed in a bottle with a cover and slightly heated. After it melts into a homogeneous flow state, it should be immediately poured into an oil cup, covered with a lid, cooled to room temperature, and then placed in a bath jacket. ② During continuous testing, the air bath jacket should be cooled to room temperature before the oil cup is placed. 5 Correction of the effect of atmospheric pressure on flash point
5.1 When the atmospheric pressure is higher than 775 or lower than 745 mmHg, the flash point obtained in the test shall be corrected according to formula (1) (calculated to 1°C): to = t+ At..
Where: t. - flash point at 760 mmHg, °C, flash point at P mmHg, °C;
At—correction number, °C.
5.2 Correction number t is calculated according to formula (2):
t=0.00012 (273+t) (760-P)
Where: P—atmospheric pressure.
6 Precisionbzxz.net
6.1 The difference between two parallel determination results and their arithmetic mean shall not exceed 1°C. 6.2 Take the arithmetic mean of the parallel determination results as the flash point of the sample. Additional Notes:
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China and is technically managed by the Shenyang Chemical Research Institute of the Ministry of Chemical Industry. This standard was drafted by Nanjing Zhongshan Chemical Plant. The main drafters of this standard are Zhang Junzhi and Tao Deming. 618
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