VAT 615 Series Installation, Operating, & Maintenance Instructions page 36

Gas flow calculation for LEARN:
Do not apply a different gas flow for learn than determined below. Otherwise pressure control
performance may be insufficient.
Note: Required pressure / flow regime must be known to calculate the most suitable learn gas flow for a specific
application.
2. 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.
1000 q
C =
WP
p
WP
q
WP
C =
WP
p
WP
q
WP
C =
WP
78.7 p
3. Out of these calculated conductance values choose the lowest.
C = min(C C
R WP1, WP2, . . . ,
Note: To make sure that the valve is capable to control the most extreme working point verify that
≥ C
C of the valve (refer to «Technical data»).
R min
4. Calculate gas flow for learn with Pmax <1mbar. Choose the applicable formula depending on units you are familiar
with. (molecular)
p C
max
q =
L
2000
p C
max
q =
L
2
q = 39.4 p
L max
VAT Vakuumventile AG, CH-9469 Haag, Switzerland
Tel +41 81 771 61 61 Fax +41 81 771 48 30 CH@vatvalve.com www.vatvalve.com
Installation, Operating & Maintenance Instructions
Series 615 DN 40 (I.D. 1½"), DeviceNet
C required conductance of working point [l/s]
WP
WP
q gas flow of working point [Pa m
WP
p pressure of working point [Pa]
WP
C required conductance of working point [l/s]
WP
q gas flow of working point [mbar l/s]
WP
p pressure of working point [mbar]
WP
C required conductance of working point [l/s]
WP
q gas flow of working point [sccm]
WP
p pressure of working point [Torr]
WP
WP
C required lower conductance [l/s]
C )
R
WPn
C required conductance of working points [l/s]
WPx
q gas flow for learn [Pa m
L
R
p max. pressure to control [Pa]
max
C required lower conductance [l/s]
R
q gas flow for learn [mbar l/s]
L
R
p max. pressure to control [mbar]
max
C required lower conductance [l/s]
R
q gas flow for learn [sccm]
L
C
p max. pressure to control [Torr]
R
max
C required lower conductance [l/s]
R
3
/s]
3
/s]
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