Backwashing is due to the fact that the tail gas is easily dissolved in the treatment liquid, and the internal air pressure instantly decreases, while the external air pressure acts on the surface of the tail gas treatment liquid and enters the reaction device along the air duct.
The inverted funnel and its variants are as follows:
The one on the left is called inverted funnel. When the tail gas is dissolved in the treatment liquid, the air pressure in the funnel instantly decreases and the atmospheric pressure acts on the surface of the treatment liquid. At this time, the treatment liquid climbs up along the funnel.
When climbing to a certain height, the liquid in the funnel is separated from the liquid level of the beaker, and the liquid in the funnel falls back into the beaker under the action of gravity. So as not to enter the reaction device along the air duct.
The one on the right is called belly-hugging, and it uses a spherical drying tube. Its principle and function are the same as those of the funnel, so I won't repeat them. In fact, this design will suck a part into the "protruding belly" of the spherical dryer, so it is called the belly-hugging type. When the funnel cannot be found in the laboratory, it can be used as a substitute for the inverted funnel.
After all, funnels are easier to clean than spherical drying tubes.
Two common safety bottles are as follows:
The characteristic of liquid storage safety bottle is that the air inlet pipe must be short, and the length of the air outlet pipe does not matter.
Its design intention is to let the inhaled liquid enter the liquid storage bottle on the left, and the short inlet is above the liquid level. So that the sucked liquid does not enter the device.
The disadvantage of this design is that if a large amount of liquid is sucked back and fills the whole liquid storage bottle, the tail gas treatment liquid will enter the experimental device. However, there is generally not so much tail gas; The operator can also stop reacting when he sees that the bottle is almost full.
Balanced pressure type or short tube air inlet is characterized by having an air duct directly communicating with the outside, which is inserted below the liquid level of tail gas treatment liquid.
With this structure, when the tail gas is instantly dissolved, the air pressure in the bottle will not be reduced, and the air will be introduced through the air duct communicated with the outside. When using this device, you will see that the nozzle of the pipe keeps blowing bubbles, that is, the outside air enters the bottle to balance the air pressure.
These are the two kinds of anti-suction devices in high school. There may be structural changes, such as:
Air pressure balance type, he does not use this branched conical bottle, but uses a liquid storage bottle and a three-hole rubber plug instead.
The liquid storage type air outlet pipe is of long growth type.
These changes have no influence, and the principle and function are still the same.