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<< Click to Display Table of Contents >> Gasflow calculation for Learn |
  
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<< Click to Display Table of Contents >> Gasflow calculation for Learn |
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Do not apply a different gasflow for learn than determined below. Otherwise pressure control performance may be insufficient. Required pressure / flow regime must be known to calculate the most suitable learn gas flow for a specific application. |
1.At first it is necessary to find out about the required control range respectively its conductance values. Each working point (pressure / flow) must be calculated with one following formulas. Choose the applicable formula depending on units you are familiar with.
Set the viscous correction factor k to 1 for molecular flow - p(wp) < 1 Torr, or to 2.5 for viscous flow - p(wp) > 1 Torr.
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CWP required conductance of working point [l/s] qWP gasflow of working point [Pa m3/s] pWP pressure of working point [Pa] k viscous correction factor |
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CWP required conductance of working point [l/s] qWP gasflow of working point [mbar l/s] pWP pressure of working point [mbar] k viscous correction factor |
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CWP required conductance of working point [l/s] qWP gasflow of working point [sccm] pWP pressure of working point [Torr] k viscous correction factor |
2.Out of these calculated conductance values choose the lowest.
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CR required lower conductance [l/s] CWPx required conductance of working points [l/s] |
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To make sure that the valve is capable to control the most extreme working point verify that CR ≥ Cmin of the valve (refer to «Technical data»). |
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3.Calculate gasflow for learn. Choose the applicable formula depending on units you are familiar with.
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qL gasflow for learn [Pa m3/s] pSFS sensor full scale pressure [Pa] Cmin min. controllable conductance of valve [l/s], (refer to «Technical data»)
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qL gasflow for learn [mbar l/s] pSFS sensor full scale pressure [mbar] Cmin min. controllable conductance of valve [l/s], (refer to «Technical data»)
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qL gasflow for learn [sccm] pSFS sensor full scale pressure [Torr] Cmin min. controllable conductance of valve [l/s], (refer to «Technical data»)
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