Determination of freezing point of glycerin in antifreeze
The freezing point of pure glycerol is 17.9℃. With the increase of water fraction content in glycerol, the freezing point gradually decreases. However, when it drops to -46.5℃, if the glycerol content continues to decrease, the freezing point gradually increases
The freezing point of glycerol aqueous solution with different concentration (weight %) is 10%, -1.6℃; 30%, to 9.5 ℃; 50%, to 23.0 ℃; 66.7%, to 46.5 ℃; 80%, to 20.3 ℃; 90%, to 1.6 ℃.
Instrument for experiment
1, SH128 automatic freezing point tester, using embedded system design, automatic detection of the whole process of the test; Color touch screen; The test results can be stored; You can view historical data; The results can be printed on the instrument and automatically stirred by the machine. The experimental results can be exported through the U disk and stored in the computer for many times.
2, alcohol,
3, the standard is SHT0090-1991 engine coolant freezing point determination method
Experimental steps:
1. After unpacking the instrument, please check the accessories according to the packing list. If there is any damage, please contact our company.
2, the instrument should be carried vertically, tilt Angle along the height of the instrument swing Angle is not more than 30 degrees, placed in the dark place, place to be stable, otherwise there will be vibration after the instrument starts, affecting the service life of the instrument.
3, check the alcohol level in the cold margin tank to ensure that the alcohol level should exceed the refrigeration plate road in the cold margin. When the alcohol is insufficient, be sure to add enough alcohol first, and then carry out the experiment.
4, the instrument power supply is received in the capacity of 220V/10A above the socket, pay attention to must have a good grounding wire.
5. Take out 75 ~ 100ml sample with measuring cylinder and put it into cooling bottle.
6. Place the cooling bottle in the coolant and tighten the cork.