Hello friends, meet again with the writing of dhevils mechanic which is definitely not far away discussing the world of mechanic oil and gas industry. Where it is often reviewed related to the equipment used in oil and gas companies, related to the troubeshot that the devils mechanic used to do or sometimes interesting ideas in solving problems in the field, so that work becomes safe, smooth and happy of course.
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And now let's talk about the transmitter level with the Buoyancy model that uses a float on the dispenser. The turn up movement from the float is forwarded to a series of tools in the transmitter level that is changed into an electric unit from this electric unit and then converted to a digital number unit on the HMI
This level transmitter is often used in separators or gas scrubbers where it is used to measure the liquid level in the vessel which is then sent to the DCS for reading and the action of the liquid control valve.
The buoyancy force of the displacer is transferred via transmission lever and torque tube to operating rod of the sensor, where it acts on free end of sensor element.Four thin film metal strain gauge elements are sputtered onto sensor element, which change their resistance in the ratio of the tensile or pressure tension. These four thin film metal strain gauge elements are connected as a Wheatstone full bridge supplied from amplifier.
The voltage at the diagonal bridge section which is proportional to the effective weight is fed to the electronic amplifier as an input signal. This voltage is converted via the electronic amplifier into the 4 to 20 mA or digital two-wire output signal. The amplifier is supplied by the signal current circuit in two wire mode.
CALIBRATION:
CALCULATING WEIGHT FORCES: For LRV & URV of Displacer Level Transmitter
Displacer length = measuring range
Displacer length > measuring range (without elevation)
Displacer length > measuring range (with elevation)
Measuring span
The transmitter is designed for a buoyancy force measuring span of minimum force to maximum force in N.
Weight force
The maximum weight of the displacer FG max for level measurements. For density or interface measurements, the displacer must be dimensioned so that after deducting FA of the lighter process media, the remaining force F0 does not exceed FG max.
Determining displacer diameters
For optimum use of the transmitter, the displacer should be dimensioned so that the greatest possible buoyancy force is generated over the measuring range. On the other hand, the maximum possible diameter of the displacer must be taken into consideration. In the above graph the displacer diameter can easily be estimated dependent on the measuring span and the buoyancy force.
Measuring principle
Any body immersed into a liquid is subject to buoyancy force which depends on the liquid density. This is exploited to determine liquid level, density and interface level by suspending a displacer with constant cylindric shape into a liquid. Changes in buoyancy forces are proportional to liquid level changes and are converted to a measuring signal. The displacer is fully immersed for density and interface level detection.
That's a few stories related to this displacer model transmitter level that was taken and summarized from various sources and field experience, hopefully it can increase our insight related to the world of instrumentation in oil and gas. If you have any questions or experience related to the care of the transmitter level of this model, please write in the comment section so that sharing this experience can be useful for friends who need it. and can be a charity field for all of you.