TechnipFMC Sening MultiLevel, Инструкция по эксплуатации

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Issue/Rev. 1.4 (9/18) ║ MNF18001EN / DOK-479-E • Page 27
MultiLevel Instruction Manual Description of the Level Gauging System
For reasons related to the system, gauging systems in purely direct delivery
tanks always exhibit residual quantities in the compartment that can no longer
be measured by the level sensors.
ATTENTION:
If the delivery is stopped during the residual volume delivery (e.g. because
the delivery tank is full), it cannot be determined how much liquid from the
residual volume has already run into the delivery tank. The residual volume
is only added to the delivery when the wet leg sensor becomes dry.
Moreover, the angles of inclination of the compartment must be accounted for.
5.4. Condition for the calibration capability
5.4.1. Germany
The following fundamental requirements must be satisfied:
These requirements must already be considered during the development and
construction of the measuring tank!
• Vehicles equipped with a level measuring system require a PTB approval in Germany.
The requirements for such a vehicle are illustrated in PTB-A 4.5, among others.
• The level measuring system employed requires its own PTB approval. The requirements
are likewise illustrated in PTB-A 4.5.
• The measuring compartments and the installation position of the level sensors must be
designed such that the overall system fulfills the accuracy requirements of PTB-A 4.5.
Due to the inclination correction in particular, certain geometry requirements arise that
must be adhered to.
If necessary, TechnipFMC will be pleased to assist you in the planning phase.
• It is essential to comply with the accuracy requirement when installing the level sensors.
The level sensors must be aligned precisely in accordance with the drawing. Deviations
can lead to inaccuracies in the inclination correction. (See also drawing no. "61.251579")
• The installation must be performed such that manipulation of measurements is not
possible. Sealing points must be illustrated in the approval and in the measuring system
document.
5.4.2. Outside Germany
• So far, there are no known valid national standards or regulations outside Germany that
contain requirements for a gauging system in tank trucks.
• The working paper OIML R80-1 is currently being prepared; this is intended to be an
international recommendation for vehicles with a level measuring system. Following its
completion, it must be implemented nationally in the individual countries in order for the
installation of a gauging system in a tank truck to be formally allowed.
5.5. Operating principle of height measurement
• A magnetostrictive sensor is used for the height measurement, whose measurement
principle is based on a transit-time method. To this end a wire made of magnetostrictive
material is stretched inside the sensor pipe. A magnet installed in the float generates a
constant magnetic field at its position. Current pulses flowing through the wire briefly
generate a second magnetic field around the wire.
• At the place where these magnetic fields overlap, tension is generated that runs as a
mechanical wave along the wire and is converted into an electrical signal in the sensor
head by a piezo-ceramic transducer.