Endress+Hauser Levelflex FMP51 Modbus - Page 28

Levelflex FMP51 Modbus
28 Endress+Hauser
Notes on the mechanical load of the probe
Tensile load limit of rope probes
Sensor Feature 060 Probe Tensile load limit [kN]
FMP51 LA, LB
MB, MD
Rope 4mm (1/6") 316 5
Bending strength of rod probes
Sensor Feature 060 Probe Bending strength [Nm]
FMP51 AA, AB Rod 8mm (1/3") 316L 10
AC, AD Rod 12mm (1/2") 316L 30
AL, AM Rod 12mm (1/2") AlloyC 30
BA, BB, BC, BD Rod 16mm (0.63") 316L divisible 30
Bending load (torque) through fluid flow
The formula for calculating the bending torque M impacting on the probe:
M = c
w
⋅ ρ/2 ⋅ v
2
⋅ d ⋅ L ⋅ (L
N
- 0.5 ⋅ L)
with:
c
w
: Friction factor
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
L [m]: Level
LN [m]: Probe length
Calculation example
v
L
N
L
d
A0014175
Friction factor c
w
0,9 (on the assumption of a turbulent current - high
Reynolds number)
Density ρ [kg/m
3
] 1000 (e.g. water)
Probe diameter d [m] 0,008
L = L
N
(worst case)