Accurate Measurement of Tank Levels
Quitec enterprise introduces new technology for highly accurate measurement of the tank contents made by the German producer FAFNIR to the market.
The tank monitoring system VISI-X made by the German company FAFNIR is an important component of the technology for fuel refilling stations. The accurate measurement of volume of the product, of its temperature and continuous recalculation of the volume to the standard temperature 15 °C are the fundamentals for the quality stock management. Due to its integrated water recognition it allows for quality assurance. In combination with the outflow calculation from dispensers it can detect eventual leakage of small quantities. Via the cashier system it offers a quantity control of the output as well as a loss control and with the help of telemetry it is a highly valuable and versatile tool for the management of the stock of fuels and oils.
Each VISY-X system consists of 1 to 16 sensors VISY-Stick and the conversion unit VISY-Command. The magnetostrictive level sensors VISY-Stick provides highly accurate measurement of the product level, the water level and product temperature. The conversion unit VISY-Command contains the power supply for the VISY-Stick-Sensors and serves as the interface for the communication with the outside world. There are many possibilities for connecting cashier systems, computers, displays, modem and alarm systems.
Measurement Sensor
The sensor VISY-Stick works according to the magnetorestrictive measuring principle. A wire made from magnetorestrictive material is integrated into the sensor tube. Pulses are transmitted through the wire using the electronics of the sensor whereas the magnetic field is circular. The magnets located in the floats magnetize the wire at the float position. Due to the superposition of the two magnetic fields a torsional pulse is created and it propagates to the sensor head. Thus created time interval is detected and converted to the tank level through the electronics.
VISY-Stick is composed of the stainless steel transducer housing, stainless steel sensor tube, screw-in unit with adjustable height, product float and water float. The Stick is produced with the protection type IP68, the measuring accuracy of the filling level is better than ± 1 mm in the whole range, the measuring accuracy for the temperature is better than ± 1°C. The water recognition is continuous from 30 mm. Operating temperature range is -25 to +80 °C. The sensor is approved by the TGv 99 ATEX 1391.
Control Unit
The VISY-Command unit supplies the VISY-Stick sensors by the electricity and it processes the data from sensors. The Control Unit receives the measured values from sensors, stores them temporarily and transmits them to the superior system, ie. to the central computer. The communication with the cash system of the fuel refilling station or with a computer are available via various interfaces - i.e. RS232-C (V24). Control Unit can use all known protocols for the communication. All parameters are set to the conversion VISY-Command by computer that is equipped with user friendly programme VISY Setup. Besides the computer connection it is also possible to create a link to the host computer (i.e. to the computer of the refilling station) or to the field bus.
The VISY-Command unit is composed of the mains to supply the VISY-Stick sensor, intrinsinic safety barriers, control unit and interface for connection to the computer of the fuel refilling station. Optionally EPSI or ISFS-LON interface can be supplied. VISI-Command enables the connection of up to 16 VISY-Stick sensors. Protection type IP 55, dimensions 300 x 300 x 175 mm, operational temperature range 0 - +40 °C. Installation outside of ex-zone, certification TGV 98 ATEX 1380, explosion protection [EEx ia] IIC, alternating voltage 230 V AC +10 %, approx. 2 VA.
Display of the attendance
VISY-View displays the complete data of tanks. The information on the tank content are always up to date and available at any time. The displayed data comprise the level of the product, tank content, product temperature, temperature compensated volume, ullage, tank and product names, the water level, two alarms for water and four for product, history of supplies and alarm history for all tanks.
Visualising System
VISY-Quick software is operating the VISY-X system and it is especially suitable to use it if no attendants display is available. As well as VISI-View, the VISY-Quick displays the complete data on tanks, including the history of supplies, alarms and ullage of products. Replacing the attendance display by the VISI-View programme allows to get interesting reduction in the price of the entire system. It is possible to manage and operate the system of tank content measurement at ease - directly by the cash system due to the ready integration of the VISI-X with the cash system through known communication protocols.