TILI Automation

 Ultrasonic level instruments measure the distance from the transmitter (located at some high point) to the surface of a process material located farther below using reflected sound waves. The frequency of these waves extend beyond the range of human hearing, which is why they are called ultrasonic. The time-of-flight for a sound pulse indicates this distance, and is interpreted by the transmitter electronics as process level. These transmitters may output a signal corresponding either to the fullness of the vessel (fillage) or the amount of empty space remaining at the top of a vessel (ullage). Ullage is the “natural” mode of measurement for this sort of level instrument, because the sound wave’s time-of-flight is a direct function of how much empty space exists between the liquid surface and the top of the vessel. Total tank height will always be the sum of fillage and ullage, though. If the ultrasonic level transmitter is programmed with the vessel’s total height, it may calcula...

 Capacitance Level Measurement: Capacitive level transducer is an example of indirect measurement of level Capacitance level sensors are used for wide variety of solids, aqueous and organic liquids, and slurries. The technique is frequently referred  as RF as radio frequency signals applied to the capacitance circuit. The sensors can be designed to sense material with dielectric constants as low as 1.1 (coke and fly ash) and as high as 88 (water) or more. Sludges and slurries such as dehydrated cake and sewage slurry (dielectric constant approx. 50) and liquid chemicals such as quicklime (dielectric constant approx. 90) can also be sensed. Dual-probe capacitance level sensors can also be used to sense the interface between two immiscible liquids with substantially different dielectric constants. Since capacitance level sensors are electronic devices, phase modulation and the use of higher frequencies makes the sensor suitable for applications in which dielectric constants are ...

 Level the parameters that exist in virtually every industrial process, there are many ways to measure the level, the simplest is to use the sight glass. By using a sight glass, the height of liquid in a vessel / vessel will be physically visible, so as to make the scale on sight glass, we can immediately determine what percentage of the liquid surface height of a tall vessel / tank / vessel. In the picture, a tank connected by a transparent hose using a scale of 0-100% of the total height of the tank. This level measurement principle utilizing the properties of the liquid will fill all the space that he passed on the associated vessel. Height of liquid in the tank will be the same as the height of a liquid residing on a transparent hose that serves as a sight glass. We can directly determine height (level) of liquid inside the tank by looking at the height of a liquid residing on a transparent hose (sight glass) is. However, this information can only be served directly in the fiel...

 One of the most misunderstood concepts when dealing with transmitters is zero elevation and suppression. Elevation and suppression adjustments are frequently necessary in liquid level measurement when the transmitter cannot be installed on a level with the zero level of the tank. The definition is following, but to understand elevation and suppression, its easiest if you look at it from a mathematical viewpoint, that is described in the second part of this paragraph. Zero Elevation for an elevated zero range, the amount the measure variable zero is above the lower range value. It may be expressed either in units of measured variables or in percent of span. Zero Suppression for a suppressed zero range, the amount the measured variable zero is below the lower range value. It may be expressed either in units of the measured variable, or in percent of span. Also Read: Zero Suppression & Zero Elevation Examples Mathematically you can develop equations that will let you calibrate th...

 ULTRASONIC TECHNOLOGY Ultrasonic is a non-contact level measurement method that uses sound waves to determine the process material being measured. Ultrasonic transmitters operate by sending a sound wave, generated from a piezo electric transducer, to the media being measured. The device measures the length of time it takes for the reflected sound wave to return to the transducer. A successful measurement depends on reflection from the process material in a straight line back to the transducer. However, there are various influences that affect the return signal. Factors such as dust, heavy vapors, tank obstructions, surface turbulence, foam and even surface angles can affect the returning signal. That is why the conditions that determine the characteristics of sound must be considered when using Ultrasonic measurement. Other problematic aspects of Ultrasonic transmitters to consider include: Vacuum Applications Sound must travel through a medium (usually air) The absence of air mol...

 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 el...

 Cat and Mouse type is particularly suited to indicating contained liquid levels when viewed from long distances, e.g. provides indication at 1:1 ratio on a large vertical scale board fixed to a tank side, activated by means an internal float via a wire and pulley system. A tank on a tower installation regularly employs this method. However it requires the provision of a small hole in the tank roof for float wire access and if the gap provided between wire circumference and hole diameter is greater than 0.65 mm the unit is not suitable for wholesome water tanks. A further disadvantage, which requires getting used to, the indicating pointer has a reverse action. When the tank is full the indicator is at its lowest point and when empty its at its highest.