The working principle of the foam pump head is similar to the emulsion pump head. The air in the straw is emptied through the spring to form a vacuum. This process is the first 3-5 times before we start to press the pump pair. Three conditions are indispensable for the liquid to spray foam. One is that the liquid itself must have a foaming agent, the other is the above-mentioned atmospheric pressure, and the third is the mesh contained in the foam pump head (located below the foam pump head pressure, Pull it out to see) The foam pump's spray volume depends on the pump core volume, which involves volume and pressure calculations. The usual spray volume on the market is 0.4cc\0.8cc\1.2cc\1.5cc, and the control of the spray volume depends on the air pressure, pump core volume, and stroke.