Appendix
Deltatop DP71B, DP72B, DP73B
46
Hauser
9
Appendix
9.1
Measuring principle
P01-DPxxx-15-00-00-xx-002
The front of the Pitot tube is exposed to the static pressure p
stat
plus the dynamic pressure p
dyn
. The
side and the back of the tube is exposed only to the static pressure p
stat
. The resulting
differential
pressure
Δ
p
can be used to calculate the
flow rate Q
.
The relationship between flow rate (Q) and differential pressure (
Δ
p) is given by a square root
function:
P01-DOxxxxx-15-xx-xx-xx-008
Downstream of the Pitot tube the static pressure p
stat
is reduced by the permanent pressure loss
Δω
.
With Pitot tubes this pressure loss
Δω
is much less significant than with other primary elements.
+
+
–
–
D
p
p
+p
dyn
stat
p
stat
p
Δ
Q ~
