Endress+Hauser Fieldbus Levelflex M FMP43 Operating Instructions Manual page 19

Levelflex M FMP43 with FOUNDATION Fieldbus
Endress+Hauser
3.3.3 Special instructions
When installing in tanks with agitator, observe the lateral loading capacity of rod probes:
• 10 Nm with 1.4435 / SS316L
• 16 Nm with Hasteloy C22 (on request).
The formula for calculating the bending torque M impacting on the probe:
r
2
M = c · · v · d · L · (L − 0.5 ·L)
2
W
with
c : Friction factor
w
ρ [kg/m
3
]: Density of the medium
v [m/s]: Velocity of the medium perpendicular to the probe rod
d [m]: Diameter of the probe rod (8 mm)
L [m]: Level
L [m]: Probe length
N
Calculation example
Friction factor [c
w]
3
Density [ρ] in kg/m
Probe diameter [d] in m
L = L (worst case)
N
Bending torque [M] on rod probes
20.0
18.0
16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
0.4 0.8 1.2
N
0.9 (on the assumption of a turbulent
current (high Reynolds number ))
1000 (e.g. water)
0.008
1.6 2 2.4 2.8 3.2
Probe length [ ] in meters
L
N
v
d
L00-FMP43xxx-16-00-00-xx-003
v=0.5m/s
v=0.7m/s
3.6 4
v=1.0m/s
L00-FMP43xxx-16-00-00-de-004
Installation
L
N
L
19