What kinds of snorkels are there?
The simplest breathing tube is composed of a bite and a plastic elbow. When water is poured from the nozzle, it is necessary to use the method of fierce blowing to blow the water from the lowest bite to the uppermost nozzle.
On the basis of the wet breathing tube, a single drain valve is installed at the lowest end of the elbow. In this way, when the breathing tube enters the water, it only needs to blow gently, and the water will be discharged from the lower drain valve without spraying from the top nozzle. However, if the membrane of the drain valve does not return normally, water will flow into the pipe during suction.
On the basis of the semi dry breathing tube, a waterproof valve is installed at the upper pipe orifice, and the valve switch is controlled by a float. When the water surface is about to pass through the pipe orifice, the float rises and closes the valve. After the water level drops, the float falls and the valve opens, so that there is almost no water in the breathing tube.
It seems that the function of the full dry breathing tube is more perfect, but the waterproof valve often cannot be opened normally after the water level drops, resulting in the user's inability to breathe. In addition, the full dry breathing tube with many functions is heavier and hung on the side of the face mirror, which hinders underwater activities. Therefore, the breathing tubes equipped by most professional hydropulmonary face mirror manufacturers are semi dry breathing tubes. After mastering the drainage skills of breathing tube, scuba divers prefer to choose semi dry breathing tube, while free divers prefer more portable and lightweight full wet breathing tube because they are more skilled in controlling breathing.