Caroline -chdurie2 wrote:roberto and others:
the shell sample has six holes, just as the regular one does, and each hole in the shell sample is twice the size of the ones in the regular shell. By my calculations, that means the shell sample reduces the amount of air going out by 50%.
Now you are saying that the sample(beta) shell has holes "twice" the size of the original .... that is opposite of what you posted previously stating that sample(beta) shell has holes size of 1/16 and original(sold product)has 1/8 ... [1/16 is one-half smaller than 1/8].
So uhhhh ... which is it? I guess I could measure mine and deduce the answer but I am away from home right now.
Also, the reduction in air is not linear (ie. half size holes does NOT mean air reduction by half). Area is calculated as PI times radius squared. So the difference is: if you halve the hole diameter, you reduce the area to 25% of original or if you double the hole diameter, you increase area by 4 times ... make sense?
Actually it is a little more complex than that because the machine's pressure setting also has a non-linear relationship to the exhaust air flow such that: as pressure is increased, the exhaust flow also increases exponentially when holding the exhaust hole area constant ... so you have to consider both area of holes and the pressure [Probably way more info than most want to know ... unless you are a geek like me ].
Thanks again for clearing things up,
- roberto