Okay, here is my quick 20 minute search driven self education.
What I am calling a “Diaphragm pump” actually applies to both designs, as they are both creating airflow by vibrating a diaphragm back and forth.
The louder models I was referring to, are called “Linear” pumps as they have a single diaphragm which is acted upon by a motor (hence the noise) which draws and then compresses the diaphragm. See below:
The quieter models I called out, are similar but are driven “Magnetically” instead of by a spinning motor, hence the far more quiet operation. See below:
Now as seen in the magnetically operated pump, it actually has two diaphragm bellows, which can produce more air flow using the same magnetic operation. This is why the units in my laser have manifolds on both sides of the aluminum housing, and a plenum that brings them together to one output point. See below:
Not a bad explanation for a guy that didn’t know any of this 20 minutes ago (even if I do say so myself).
