External Roughing Pump 1

[Osakasalem]

Dear All,

im preparing for a roughing pumping system design , the pump will be placed outside of the experimental hutch , the piping connection will be almost 7 meters!

i will be using the pfiffer root pump 500 l/s DN 100 to the buffers and then there will be turbo pump, i dont have any formulas for calculations, and i would appreciate if you can state main points in design to consider , choking ratio , conductance calculation.

if the info i ve given is not sufficient i would be glad to supply more

Thank you , have a good day!!

Cheers

 

[LittleInch]

Osakasalem - I'm sorry but your question doesn't make sense and is far too broad a question to ask. Pfieffer Root pump is a vacuum pump so not sure what system it is connected to, 500l/sec = 1800 m3/hr - a large flow rate which seems too large for those types of pumps.

Roughing pumping, Experimental hutch, choking ratio, conductance calculation mean nothing to me - have you been using google translate? There is help on this site for people who do not have a good command of english to get their questions translated. I suspect you need to use that and also be more precise in your description (sketches and drawings help a lot) and what your problem is.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[ScottyUK]

LittleInch,

Quite a few years have passed since I was in the microelectronics industry, but from memory a 'roughing pump' in a vacuum application is the name for a rotary pump used in conjunction with a high vacuum turbo-molecular pump. The high vacuum pump exhausts into the intake plenum of the roughing pump. I'm no expert on high vacuum pump technology, but in essence the high vacuum pumps can't operate as a single stage from high vacuum to atmospheric and they need to exhaust into a vacuum themselves. I'd imagine that Edwards have some information on their website if you want to read a bit more.

 

[LittleInch]

Thanks,

I'd never come accross those terms before, but have only dealt with vacuum systems once or twice so will back out of this one...

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[Compositepro]

This might help.

http://isnap.nd.edu/Lectures/urls/LEYBOLD_FUNDAMENTALS.pdf

 

[ScottyUK]

An excellent reference - thanks.

 

[Osakasalem]

LittleInch - thank you for the note , i totally agree that the question is very broad and not clear enough , and sorry for not illustrating the problem clearly , maybe i had to mention the application its used for. im just new here and its my first thread , so now i can learn from it. im not a native speaker but the problem was in explaining not the English as u understood what i wrote and it only didn't make sense to u, but the terms i used would be very clear to someone working in the same field.

ScottyUK- you are right with the description of roughing pump , rough vacuum is achieved using pumps working in higher pressure ranges till 10^-3 reaching high vacuum range , where you would need high vacuum pressure pump like Turbo pumps.


Compositepro- thank you for the reference , its very useful of course. i also find (Pfiffer -Vacuum technology know how

http://www.triumf.ca/sites/default/files/lecture_vac_Pfeiffer-Vacuum-Technology-KnowHow.pdf

)more detailed , but still not sufficient with equation for connecting pumps externally.


To Clarify , im working in an Accelerator facility , building Xray and laser beams which has to operate in vacuum.
my problem is that i have to evacuate a beam section( 25 meters- divided into 3 pressure ranges ) and place the roughing pump( root pump 500l/s) away by 7 meters through long pipes , then along the beam line , around 10 more turbo pumps will be connected in a position accordingly to reach the different pressure range.

the problem when connecting the roughing pump through this long pipe , the geometry of the pipe (having right angles) and the conductance (the flow resistance ) decrease the efficiency of pumping.

the i was wondering if there would be equations for long piping connection , and the choke ration which is a relation between L and R of the pipes , and any other consideration i should notice while designing the system.

i appreciate the support , and if there is still information missing please help me to supply it fully.thank you