BCU 460, BCU 465 · Edition 11.19 45
Valve proving system
6.1.5 Measurement time t
M
The sensitivity of the tightness control in the BCU can
be adjusted for each individual system by adapting the
measurement timet
M
. The longer the measurement
timet
M
, the greater the sensitivity of the tightness
control. The measurement time is set using parameter
A056 to a value between 3 and 3600s, see page101
(Measurement time for Vp1).
The required measurement time t
M
is calculated from:
Inlet pressure p
u
[mbar]
Leakage rate Q
L
[l/h]
Test volume V
p1
[l]
Calculation of the test volume, see page46 (Test volume Vp1)
For one test volume V
p1
between 2gas solenoid
valves
Adjustable using parameterA056
t
M
[s] =
(
2 x p
u
x V
p1
)
Q
L
For a large test volume V
p1
with reduced testing
time
Adjustable using parameterA056
t
M
[s] =
(
0.9 x p
u
x V
p1
)
Q
L
Conversion into US units, see page136 (Converting
units)
Leakage rate
The BCU tightness control makes it possible to check
a specific leakage rate Q
L
. Within the European Union,
the maximum leakage rate Q
L
is 0.1% of the maximum
flow rate Q
(N)max.
[m
3
/h].
Leakage rate Q
L
[l/h]
=
Q
(N)max.
[m
3
/h] x 1000 [l/h]
1000 x 1 [m
3
/h]