TC · Edition 08.17 29
Function
3.2.2 Test procedure TC 4
The TEST starts with the waiting time t
W
. Once the wait-
ing time has elapsed, the tightness control TC checks
the pressure between the inlet valve V1 and the outlet
valve V2:
Depending on the pressure between the valves p
z
, the
tightness control TC carries out a check using test pro-
cedure A or B:
If pressure p
z
> p
u
/2, program A starts.
If pressure p
z
< p
u
/2, program B starts, see page 30
(Test procedure B).
+
–
V2
OK
V1
OK
t
L
= 2 s
t
M
+
–
t
M
p
z
>
p
u
2
+
–
V2
V2
V2
p
z
>
p
u
2
V1
OK
V1 V2
OK
V1
V1
t
L
= 2 s
p
u
p
u
p
z
V1 V2
PZ
2
Test procedure A Test procedure B
START
Test procedure A
If pressure p
z
is greater than half the inlet pressure p
u
/2,
valve V2 is tight. Valve V2 is opened for the opening
time t
L
= 2 s. V2 closes again.
During the measurement time t
M
, the tightness control
checks the pressure p
z
between the valves.
If pressure p
z
is greater than half the inlet pressure p
u
/2,
valve V1 is leaking.
If pressure p
z
is less than half the inlet pressure p
u
/2,
valve V1 is tight.
The tightness test can only be performed if the pres-
sure downstream of V2 is around atmospheric pressure.
+
–
V2
OK
V1
OK
t
L
= 2 s
t
M
+
–
t
M
p
z
>
p
u
2
+
–
V2
V2
V2
p
z
>
p
u
2
V1
OK
V1 V2
OK
V1
V1
t
L
= 2 s
t
W
p
z
>
p
u
2
TEST
Test procedure A Test procedure B
START