Honeywell BCU 465 - Page 43

BCU 460, BCU 465 · Edition 11.19 43
t
L
= A059
t
M
= A056
p
Z
>
p
u
2
+
–
OK
V1
V1
V1
OK
V2
V1
V2
p
Z
>
p
u
2
+
–
t
L
= A059
t
M
= A056
V2
V2
t
L
= A059
t
M
= A056
+
–
V2
OK
p
Z
>
p
u
2
V1
OK
V1
V2
V2
V2
p
Z
>
p
u
2
+
–
t
L
= A059
t
M
= A056
V1
V1
p
Z
>
p
u
2
+
–
PZ
V1 V2
p
z
p
u
/2
Program A Program B
START
Valve proving system
Program B
Valve V2 opens for the set opening timet
L
. V2 closes
again. During the measurement time t
M
, the tightness
control checks the pressurep
Z
between the valves.
If pressurep
Z
>p
u
/2, valveV1 is leaking.
If pressurep
Z
<p
u
/2, valveV1 is tight. ValveV1 is
opened for the set opening timet
L
. V1 closes again.
During the measurement time t
M
, the tightness control
checks the pressurep
Z
between the valves.
If pressurep
Z
<p
u
/2, valveV2 is leaking.
If pressurep
Z
>p
u
/2, valveV2 is tight.
The tightness test can only be performed if pressurep
d
downstream of V2 is around atmospheric pressure and
the volume downstream of V2 is at least 5× higher than
the volume between the valves.