Dynamic Behaviour Of The Chemical Seals - Vega VEGADIF 65 Operating Instructions Manual

Step response time
Chemical seal CSB • for VEGADIF 65
80
60
40
20
0
–20
–40
0 1
Fig. 6: Permissible ambient temperature range depending on the capillary
length for chemical seals of group E
•
Group F
– DRD DN 50 (65 mm), PN 25, 316L
80
60
40
20
0
–20
–40
0 1
Fig. 7: Permissible ambient temperature range depending on the capillary
length for chemical seals of group F
3.3

Dynamic behaviour of the chemical seals

The viscosity of the filling oil, the capillary length as well as the inner
diameter influence the frictional resistance. The higher the frictional
resistance, the longer the step response time. The step response time
is also influenced by the control volume of the measuring cell. The
smaller the control volume of the measuring cell, the shorter the step
response time.
The following diagram shows the typical step response times (T90) of
the different filling oils depending on the measuring cell and capil-
lary inner diameter. The values are specified in seconds per meter
capillary length and must be multiplied by the actual length of the
capillaries. The step response time of the transmitter must also be
taken into account.
3 Planning instructions for isolating systems
Group E
permitted
operating range
2 3 4 5
Gruppe F
erlaubter
Einsatzbereich
2 3 4 5
6 7 8 9
Capillary length [m]
6 7 8 9
Kapillarlänge [m]
10
10
11