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Series 642
Gasflow calculation for LEARN:
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.
C
C
C
2. Out of these calculated conductance values choose the lowest.
C
= min(C
R
3. Calculate gasflow for learn. Choose the applicable formula depending on units you are familiar with.
q
=
L
q
=
L
q
= 71 p
L
603685EA
INSTALLATION
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.
C
1000 q
WP
=
q
WP
WP
p
p
WP
WP
C
q
WP
=
q
WP
WP
p
p
WP
WP
C
q
WP
=
q
WP
WP
78.7 p
p
WP
WP
C
C
C
)
WP1,
WP2, . . . ,
WPn
C
To make sure that the valve is capable to control the most extreme working point verify
≥ C
that C
of the valve (refer to «Technical data»).
R
min
q
p
p
C
SFS
min
C
1100
«Technical data»)
q
p
p
C
SFS
min
C
1.1
«Technical data»)
q
p
C
C
SFS
min
«Technical data»)
Edition 2013-08-22
required conductance of working point [l/s]
WP
gasflow of working point [Pa m3/s]
pressure of working point [Pa]
required conductance of working point [l/s]
WP
gasflow of working point [mbar l/s]
pressure of working point [mbar]
required conductance of working point [l/s]
WP
gasflow of working point [sccm]
pressure of working point [Torr]
required lower conductance [l/s]
R
required conductance of working points [l/s]
WPx
gasflow for learn [Pa m
L
sensor full scale pressure [Pa]
SFS
min. controllable conductance of valve [l/s], (refer to
min
gasflow for learn [mbar l/s]
L
sensor full scale pressure [mbar]
SFS
min. controllable conductance of valve [l/s], (refer to
min
gasflow for learn [sccm]
L
sensor full scale pressure [Torr]
SFS
min. controllable conductance of valve [l/s], (refer to
min
3
/s]
35/73
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