The sensor is used for continuous noninvasive, digital, automatic measurement of LPG level and other liquids such as water, chemicals.
Sigma ULB measures the level mainly in aboveground stationary cylindrical metal tanks from 10 cm up to 4 meters depending of the liquid density.
The sensor has measurement error from 5% up to 1 mm depending on the model. Can be installed in the 0 explosive zone.
The sensor is a device that consists of one or two ultrasonic emitters / meters connected to a signal converter.
The converter is connected to intrinsically safe unit. The barrier is not included in the installation set and supplied as a separate, independent product.
Sigma ULB has RS 232, RS 485 output and can be easily connected to GPS tracker, PC board, notebook or digital indicator.
The sensor range consists of the following versions:
• ULB-10 - 1 ultrasonic meters with inbuilt temperature sensor + converter. Measuring error – 5%
• ULB-20 - 2 ultrasonic meters, one with inbuilt temperature sensor + converter and intrinsically safe unit. Measuring error – 2%
• ULB-30 - 2 ultrasonic meters + separate temperature sensors depending on tank size, + converter and intrinsically safe unit. Measuring error – 1mm.
Ultrasonic meters and converter have II2GExibIIВT4Gb explosive marking.
Intrinsically safe unit has II(1)G[ExiaGb]IIB explosive marking.
Installation should be done according to the manual with the qualified specialists.
|Bottom installation of the ultrasonic meter|
Bottom installation of ultrasonic meter with inbuilt temperature sensor + side installation of the second ultrasonic
Bottom installation of ultrasonic meter + side installation of the second ultrasonic meter. A number of temperature sensors depending on the tank size.
General installation scheme
Sigma ULB emit ultrasonic waves into the tank and receive the reflected signal, which is transmitted to the converter.
The lower ultrasonic meter measures the distance to the separation of liquid.
The side ultrasonic meter is used to measure the properties of the liquid (speed of sound). It corrects the readings of the lower meter in order to increase the accuracy of measurements.
In the ULB-30 model, a number of side mounted temperature sensors are connected to the ultrasonic meter. They measure the temperature of the liquid, which is also intended to increase the accuracy of measurements.
The converter calculates the level according to the results of processing information from the meters. It transmits data through the external galvanic isolation in the intrinsically safe unit. The unit, in its turn, is connected to external device for further processing via the RS-485 or RS-232 interface.
|ULB sensor characteristics||Value|
|Measurement error :|
Temperature range, °С
|– 40 … + 75|
|IP protection rate||IP67|
|Explosion-proof marking||II 2G Ex ib IIВ T4 Gb|
|Intrinsically safe unit characteristics||Value|
|Voltage, V||+9 …+36|
|Temperature range, °С||– 40…+ 75|
|IP protection rate||IP67|
|Current consumption, max mA||250|
|Explosion-proof marking||II (1) G [Ex ia Ga] IIB|