KROHNE BM 70 A_P EN - Manual (Page 26)

Installation and operating instructions BM 70 A/P Page: 26 11/00
6.2.8 Shock resistance
The device has been found to withstand the impact test in conformity with EN 61010, Section 8.2,
with 0.5 J energy, and the drop test to prEN 50178:1994.
6.2.9 Vibration endurance limit
Type test conditions: to IEC 68-2-6 and prEN 50178 (10-57Hz: 0.075 mm / 57-150 Hz: 1 g)
6.2.10 EMC
The devices satisfy the requirements of EN 50081-1, EN 50082-2 and the NAMUR Recommendation.
6.3 Product conditions
6.3.1 Physical properties of the products
Physical properties (such as density, viscosity, conductivity, relative permittivity, magnetic properties,
etc.) have no effect on measurement results.
The relative permittivity is merely required to have a minimum value in order to ensure reliable
measurements (see Section 6.3.2).
6.3.2 Relative permittivity (
εε
r
≥≥
1.5)
The (relative) permittivity of the product (
ε
r , Epsilon-R) determines the strength of the reflected
signal. Measurement results are not affected so long as the reflected signal is strong enough, but
reliability and the maximum measuring range are dependent upon the relative permittivity.
At
ε
r < 3, a stilling well should be used. The minimum relative permittivity of the product is
approximately
ε
r = 1.5.
See also Section 7.5.
If the Wave-Stick is also to take measurements when immersed,
ε
r will need to be > 4.
0%
10%
20%
30%
40%
50%
60%
70%
1 1.2 1.6 2 2.5 3.2 4 5 6.3 8 10 12 16 20 25 40 50 63 80 32
Dielectric Constant and Reflection Factor
R
ε
r Water
Benzene
Toluene
Petrol
Chlorine
Phosgene
Methanol
LPG Sulfuric acid
Sulfur
Phenol
Nitrobenzene
Glycol
Paraffin
U S E A B L E R A N G E