VEGA VEGADIF 34 … 51 - Manual (Page 53)

VEGADIF 34 … 51 53
20094-EN-030731
∆
p
h = ––––––
e • g
Installation connections
The hydrostatic pressure corresponds to the
level of the product, measured from the centre
of the flange isolating diaphragm, multiplied by
the specific gravity of the product (because
the overlaid pressure acts on the plus side as
well as on the minus side of the transmitter, it is
compensated in differential pressure genera-
tion).
∆
p =
ρ
• g • h
∆
p: Hydrostatic pressure [N/m 2 ]
ρ
: Density of the fill fluid [kg/m 3 ]
g: Acceleration due to gravity [m/sec 2 ]
h: Level [m]
Note:
- If the transmitter is installed below the min.
level, the resulting height difference for the
adjustment of zero and span must be taken
into account (the liquid column in the capil-
lary line influences the measurement result).
- Unlike single pressure transmitters, differ-
ential pressure transmitters are selected
only according to the expected pressure
difference. As long as the overlaid pressure
does not exceed the permissible nominal
pressure, it does not have to be taken into
account. The selected measuring range can
thus be perfectly adapted to the expected
pressure difference.
∆
p
h = ––––––
ρ • g
This mounting arrangement is only permissible
if no vacuum can occur (even temporarily).
This mounting arrangement is recommended if
a vacuum can occur. It prevents the pressure
column in the capillary tube from being dis-
rupted.