What Is The Principle Of The Foam Pump in Life?

What Is The Principle Of The Foam Pump in Life?

The hand sanitizer is still liquid in the bottle, but it turns into foam when squeezed out. The structure of this kind of foaming bottle that has become popular in recent years is not complicated, but a foaming structure is added on the basis of the original push-type suction pump.

When we press the pump head on an ordinary hand sanitizer bottle, the piston inside the pump presses down, and at the same time, the downward valve (the small bead under the spring) closes, and the air in it is forced upward.
 

Ordinary push-type suction pump principle

After letting go, the spring returns and the lower valve opens. At this time, the air pressure in the pump becomes lower, and the atmospheric pressure will "squeeze" the liquid into the suction pipe.

The foaming bottle has a larger chamber near the pump head for making and storing foam, which is connected to a small pump for air intake.

The secret to the rapid mixing of air and liquid is also the mesh structure. If you turn on the hand pump head of the sparkling bottle, you will see that there is a screen on the way the liquid must pass.

Unlike regular pump heads, foam pump heads have an inflated air chamber at the throat. When released after the first press, a low pressure is created in the upper part of the pump head, which draws the liquid to the upper part of the pump head, and at the same time air enters the air chamber. On the second press, the air chamber is pressurized, pumping both liquid and air through a screen located on the tube, which blows out bubbles. The smaller the mesh, the smaller the bubbles and the finer the foam.

The detergent in the bottle usually needs to be pre-diluted with water, and the liquid passes through a nylon mesh full of small holes before being pumped into the chamber. This net acts like a bath flower or a sponge, and the porous structure allows the surfactant in the detergent to fully contact with the air in the cavity to form rich foam.

The "mousse" used to shape hairstyles is also a kind of foam. Its foaming principle is different, and it needs the help of a propellant. This reagent is liquid in the high-pressure environment in the bottle. After it exits the nozzle, it immediately vaporizes and expands under normal pressure, turning the liquid material mixed with surfactant into foam.