6 replies to this topic

[S.R.Shah]

Hi;

How to calculate to evacuate 1 KL Vessel to 1mm Absolute pressure from Atmospheric vessel with Fixed capacity of Vacuum Source say 5000 lpm at 25 Deg C.

Specific Volume of Air Increases as pressure reduces.(Density= Pressure in Bar X Molecular Wt. in Kg/Kg Mole/Uni .Gas Constant x Temperature in Deg K).By calculating at equal Increments of Pressure ,and summing up total time,One can come to final time.I used this methos but time taken came quite long app. 10 Hrrs.

Please also find excel Spread sheet.Please correct.
Can anybody give any good reference?

Thanks in Advance.

SRShah

Attached Files

•  time taken to evacuate vessel.xlsx   11.44KB   35 downloads

[Bobby Strain]

Look here. http://www.engineeri...time-d_844.html

Bobby

[S.R.Shah]

Bobby;

Thanking you.

Can you correct me in my calculations?

I have included calculations by Formula in my excel sheet.

SRshah

Attached Files

•  time taken to evacuate vessel.xlsx   24.92KB   25 downloads

[breizh]

http://www.vacuum-gu.../technikfaq.htm

An other resource , take account possible leak like gasket , metal porosity .....


should be less than few minutes :t= 1000/5000*ln(1013/1).

Breizh

Edited by breizh, 06 October 2012 - 11:40 PM.

[S.R.Shah]

Thanks Bobby and Breiz.

I realised my mistake in spreadsheet.

Will you please give thumrule for selection of apprpriate vacuum system for volume of tank?

SRShah

[breizh]

You may consider talking to vendors like Edwards Sihi, Bush, or local vendors for vacuum pums. Several technolgies are available like dry vacuum pump or liquid ring pump - even steam ejectors.

Now for calculation you should refer to a worksheet issued by Art Montemayor.

hope this helps

Breizh

[S.R.Shah]

Thanking you Briezh and Art.

SRShah