KROHNE BM 100A Handbook User Manual
Page 61
Handbook BM 100 A
61
Simultaneous interface & level measurement of two products
Interface can be measured when the top liquid has a lower dielectric constant than the second one.
The residual pulse left over from the reflection from the top liquid surface is used for measuring
interface distance. This residual pulse continues along the probe until it is reflected by the liquid /
liquid interface. The speed of the electromagnetic pulse through the top liquid is determined by the
top liquid’s dielectric constant. This relationship is expressed by this formula :
c
1
= c
0
, where
ε
r1
is the dielectric constant of the top liquid
√
ε
r1
and c
1
is the pulse’s speed in the top liquid
The distance to the interface may be determined if the distance to the top product surface and
ε
r1
is
known, as the layer thickness is proportional to time and
ε
r1
(see diagram above). The layer must be
a minimum of 100mm / 4” thick for an accurate measurement to be taken.
8 Certificates
and
Approvals
ATEX*
KEMA 01 ATEX 1078X
EEx de [ia] IIC / IIB (T6-T3) : (ATEX II 1 / 2 G)*
or
EEx d [ia] IIC/IIB (T6-T3) Zone 0 (ATEX II 1 / 2 D
T75 – 150°C)*
Factory Mutual*
Project ID 3009217
Intrinsically safe apparatus for use in Class I, II,
III, Div. 1, Groups A – G & connections to Class
I, Zone 0 AEx ia IIC;
for Nonincendive Class I, Div.2, Groups A – D ;
suitable for class II, III, Div.2, Groups F & G; with
Type 4X, 6 indoor / outdoor protection.
Germanischer Lloyd Certificate*
No. 17 461 - 01 HH
Gauge tested in accordance with the relevant
requirements of the GL Type Approval System.
Gosstandard Pattern Approval Certificate
No. 17045-98 (Russia)*
Gauge tested in accordance with the approval
requirements of the Gosstandard System.
Symbols used for the identification of approved equipment
Conformity
to E.U.
directives
and norms
Ex-
approved*
FM-
approved*
GL-
approved*
*The above symbols, with the exception of the “CE” symbol, will not appear on gauge nameplates or
supplied paperwork if the approvals are not specified in the order by the customer.