Chemistry is an experiment based science. In the process of chemical experiment, all the instruments and devices involved in gas preparation, collection and gas reaction should be checked by air tightness. The tightness test shall be carried out prior to the completion of the instrument connection and before the addition of the medicine. Methods the air tightness testing although varied, but the general principle is: blocked a head to take certain measures to generate a certain pressure difference, corresponding phenomenon, then analysis of the phenomenon of conclusion, in order to determine whether the good air tightness device. However, due to the differences of different experimental instruments and devices, the methods and methods used in the test are also different.
1, micro heat method.
The operation process: the tail end of the air duct into the water -- hold on the instrument or device micro - catheter. Whether the end bubble -- after releasing the hand - whether the formation of a distal end of the catheter to observe water column, use hot towel if the container is good air tightness. Check the tightness of the device as shown in figure one or two.
2 direct heating method.
When the device is composed of a sealing system is large, with hands or hot towel is not easy to cause the change of air volume, the use of alcohol lamp heating device directly to the distal end of the catheter is observed, if the bubble, loosen the hand or removed after the heat source - tube end forming a water column, then the air tightness device.
3, liquid difference method.
Operation procedure: close the guide piston, on the system to tracheal hp-l funnel of injected water to the water in the hopper above the water in the container, put it aside for a moment the water that formed a stable liquid position difference, that the good air tightness device. Check the tightness of the device as shown in figure four.
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