Yes, measuring the pressure of the vacuum. And yes, maybe not many people have experience or direct knowledge, could be.
The dimensions are as follows, for two cases (in mm):
* Penning is typically DN40
* Pipe from penning to valve is DN40 or DN16, ~75 mm long
* Valve is DN40 or DN16
*...
No ideas at all? I was thinking it might be due to free path length being a lot more then the length and diameter of the pipe in front of the Penning.
If the inlet to this pipe is made smaller, molecules might get trapped inside the pipe?
We use, among others, Penning pressure gauges for determining pressures (aprox. 1E-7 to 1 mbar (about the same in Torr... for the Americans here ;-) ).
The Penning is placed just outside the recipient, behind a valve to make sure its never in pressures of 1mbar or more.
When using a smaller...
Some applications need high precision, some don't ;-)
For the friction problem, any thoughts are welcome... a little brainstorm so to say.
Some more info / practical results:
* we are not using high precision equipment atm, just simple rolling cylinders (D = 4mm)
* under normal...
First of all, Hi ;-)
So I am familiar with friction and how to make estimates for it, but how about friction in vacuum?
Some thoughts of mine:
* lack of moisture, so no film
* increased adhesion (maybe due to the above)
An extra complexity by adding heat (up to 400 degrees C)
* what...