Set up your spreadsheet with the following columns to automate the calculation: XLS Cell (Example) Chamber Volume Initial Pressure cap P sub 1 cap P cap S cap I cap A Target Pressure cap P sub 2 cap P cap S cap I cap A Pump Rated Speed cap C cap F cap M Pump-Down Time min or sec = (B1/B4) * LN(B2/B3) 2. Account for Effective Pumping Speed ( cap S sub e f f end-sub Effective Pumping Speed (EPS) - Kurt J. Lesker Company
[ \frac1S_eff = \frac1S_pump + \frac1C_pipe ]
If you’d like, I can generate a with example data and formulas you can directly import into Excel. Just let me know.
| | Calculation Step | Formula Used | |----------|---------------------|------------------| | 1 | Total air leakage (seal length method) | =IF(B11="非常好", 0.03, IF(B11="好", 0.1, 0.2)) * B9 | | 2 | System leakage (volumetric method) | =VLOOKUP(B12, LeakageTable, 2, TRUE) | | 3 | System leakage (selected) | =MAX(B13, B14) | | 4 | Gas load from process | =G1+G2+G3+G4 | | 5 | Pumping speed for gas load | =S = V/t * LN(P1/P2) | | 6 | Correction for seal liquid | =IF(B21<15, 1, 0.98 - (B21-15)*0.002) | | 7 | Effective pumping speed | =1/(1/B30 + 1/C_tube + 1/C_valves) | vacuum pump capacity calculation xls
In your cell, paste the following consolidated Excel formula: =((B3 / (B4 * 60)) * LN(B5 / B6)) * B7
The key to optimal selection lies in accurate —determining the volumetric flow rate (typically in m³/h, CFM, or L/s) needed to evacuate a chamber from atmospheric pressure to a target vacuum level within a desired time.
If you are evacuating a vessel from atmospheric pressure, use this formula to determine the required speed (
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Calculated speed (S) in m³/h or CFM.
The corrected capacity is: $S_corrected = S_required / (k_1 \times k_2)$
To accurately size a vacuum pump using an Excel spreadsheet, you must define several key variables. A. System Volume (V)