How Does It Work?
Spray bottle is made of plastic which could make artificial fog, put it in a scientific way, under the atmosphere, the high-pressure system sprays the liquid out of bottle in extremely small water particles form, so that you can see those water particles suspend, float in the air like fog, yet spray bottle isn't meant to make artificial fog to let people enjoy. In most case, plastic spray bottles served many places, like the ordinary family, barbershop, and other public places, they're used widely around our life.
As I said above, the principle of spray bottle's work depends on pressure differences, and how to create pressure differences is the job of spray-bottle head, it consists of only a few parts, the plastic pipe links the bottom of the reservoir and nozzle, the trigger would activate the piston to draw liquid from bottom to top through plastic pipe.
All of the components inside
You can see clearly all the elements in the infographic below, of which the trigger, small spring and the piston compose the pump, to operate the pump, you pull the trigger back, pushing the piston into the cylinder, the function of spring is to pushing and pulling back the trigger, so as to constitute the entire pump cycle.
On the other hand, don't neglect the effect of valves, we can call this device one-way valve, which means this setting only allows the bottle spray liquids out, to stop turning back.