Lets find out how a soap dispenser works…
Here is a large picture of the tear down that I am placing here for you to go back for reference. From left to right we have a nozzle a piston and upper valve assembly a spring a check valve vall and the piston chamber and feed tube.
So first a force is applied down on the top of the soap dispenser this is marked with a yellow arrow
This force causes the spring to compress and turn the kinetic energy into stored spring potential energy
At the same time the upper section of the pump piston marked with a purple trapezoid gets forced to open due to friction on the sides of the pump. This allows soap to flow through the center and through a hole that is within this assembly and through the center and up through the top spout.
Here is a clip of the the assembly opening and closing for your reference…
The purple plunger compresses the fluid which causes the fluid to want to go to an area of lower pressure and therefore goes through the top of the soap dispenser and into the atmosphere.
There is a check valve that is basically a ball at the bottom of the chamber that the pressure in the fluid when the plunger is being compressed causes it to remain closed.
So now when we stop applying force to the pump the potential energy stored by the spring is released and turned into kinetic energy.
This causes the purple plunger to be closed and no fluid can go through the top assembly
The soap chamber is now in a state of low pressure which causes the higher pressure soap in the reservoir to push its way past the ball check valve and fill the piston chamber
Disclaimer
These videos are intended for educational purposes only (students trying to pass a class) If you design or build something based off of these videos you do so at your own risk. I am not a professional engineer and this should not be considered engineering advice. Consult an engineer if you feel you may put someone at risk.
