Vacuum System Pressure Drop Calculations

[hondashadow1100vt]

Hi,

I need to size some lines for a vacuum system for a critical service. The pressure range is from 0 to 24 inches of Mercury vacuum (in Hg V). I have looked through a number of different resources to identify the right equations to use for pressure drop in vacuum lines and performed some calculations using different methods. I am finding a lot of seemingly conflicting information that produces differing results. I am wondering what the industry best practice is for calculating pressure losses in a vacuum system. Ideally I am looking for a referral to a handbook, paper, etc. that prescribes how to do it.

I will be very grateful for any insight/feedback that can be offered in this regard.

Thank you!

 

[hacksaw]

An excellent starting point is Bernoulli's book "Mechanica" later put in algebraic form in 1759 by Leonhard Euler

 

[danschwind]

hondashadow1100vt,

I was able to find a book called "Handbook of Vacuum Science and Technology" on google that appears to be quite decent in describing vacuum systems. I recommend you to take a look on it.

But please bear in mind that if this is truly a critical service, you should seek the guidance of a more experienced engineer on this subject.

 

[hondashadow1100vt]

Thanks Danschwind. I will take a look!

 

[quark]

Have you checked Ludwig? Pressure drop in vacuum system, unlike pressurised flow, more relates to the time duration in which you need to get to a final pressure from initial pressure. You can use any low pressure gas equations.