TILI Automation

 The Torbar is employed for flow measurement of liquids, gases, or steam in circular, square, or rectangular section ducts for large flow rates. The Torbar is an insertion type multi-port self-averaging primary sensor for flow measurement. Torbar TORBAR is a set of Pitot tubes mounted on a bar across the pipeline with no moving parts. An averaging Pitot tube is a technology, while TORBAR is a manufacturing brand name. There are several brands available in the market with VERABAR, ANNUBAR, etc. Averaging Pitot Tube Principle Purpose Averaging Pitot tube can be employed when the average velocity of the flow profile, rather than the velocity in a specific point in the cross-section is desired. Averaging Pitot Tubes Principle It measures the differential pressure between the static pressure tap and the tap of full pressure of a stream. Thus such magnitude of differential pressure is directly proportional to the square of the flow rate. Working The TORBAR is designed in such a way that ...

  Introduction DPharp transmitters with advanced software functionality eliminate this time consuming task. With maintenance shops getting smaller, finding equipment that allows us to do more with less becomes a priority.Level transmitter configuration can be very time consuming. Calculations required to determine proper range values for traditional transmitters can become complex due to the physical layout of an application. Application Using typical smart or conventional products all of the following must be considered: The specific gravity of the process; Precise location of 0% and 100%; Specific gravity of the capillary fill fluid or sealing liquid (for impulse tubing); Vertical height of capillary or impulse piping; Exact orientation of the transmitter to the vessel; Vertical distance between the flanges. Depending on the application, the vessel may be open (referencing atmosphere), or closed (under some blanket pressure). Elevation is typically used when the vessel is closed....

Magnetic Level Gauge Inside the indicator tube is a lightweight magnetized indicator or series of metallic flags. The indicator is magnetically coupled to the float and moves up and down with the liquid level. The indicator allows the operator to read the level from more than 100 feet away. The only moving parts are the float and the indicator. Theory : Magnetic level gauges work on the principle of communicating vessels, therefore the level in the measuring chamber will be the same as the level in the vessel. The measuring chamber is fitted with a float, which has a magnet inside. The float with magnet will float on the medium and the magnet in the float will turn the flaps of the indicating rail. The float in the measuring tube is standard not pressurized and has no magnetic or mechanical guidance. This construction makes the float less dangerous than a float which is standard pressurized. When necessary Hadro can produce a pressurized float. With the below mentioned process conditio...

 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...

 Diaphragm seals for tanks under Vacuum The transmitter must be mounted level with or below the lowest tap to ensure positive pressure at the transmitter. Dist. Between Taps = H DP = Hside – Lside DP = (L*SGp + h*SGf ) – (H+h)*SGf DP = L*SGp – H*SGf Double Remote Seal Application Calibration Range LRV or 4mA point = Phigh – Plow LRV = Head2 – Head1 LRV = (0.9*30”) – (0.9*100”) LRV = -63”H2O URV or 20mA Point = Phigh – Plow URV = (Head2 + Head3) – Head1 URV = [(0.9*30”) + (1.1*50”)] – (0.9*100”) URV = -8”H2O Cal. Range = -63 to -8 in H2O Max. Allowable ΔS.G = 0.2 Dist. Betw. Taps = 10 ft = 10 x 12” = 120” Calibration Range LRV or 4mA point = 120” * (SGp – SGf) LRV = 120” * (1.1 – 0.95) LRV = 18”H2O URV or 20mA Point = 120” * (SGp – SGf) URV = 120” * (1.3 – 0.95) URV = 42”H2O Cal. Range = 18 to 42 inH2O Interface Calculation with Remote Seals Transmitter Application Example: To determine % of interface of Liquid A with respect to Liquid B. Dist. Betw. Taps = 10 ft = 10 x 12” = 120” C...

 The radiometric level measurements work non-contacting and non-intrusive. As the components are mounted on the outer wall, they do not come into contact with the measured material and are therefore not exposed to wear and tear. Gamma radiation, emitted from a shielded source is attenuated as it passes through the vessel. This attenuation is measured by a highly sensitive detector, mounted at the opposite side of the vessel. As type of radiation and measuring geometry are constant the attenuation will only be affected by a change in level. The continuous measurement of level uses a radiation field over the whole measuring range. If the level rises within the range of the radiation field, the attenuation becomes stronger and consequently the detector measures less radiation. In this manner, the level can be reliably monitored – irrespective of pressure, temperature, viscosity, color and all chemical properties. There are different possibilities how a radiation field is formed. Eithe...

 A radar signal is emitted via an antenna, reflected on the product surface and received after a time t. The radar principle used is FMCW (Frequency Modulated Continuous Wave). The FMCW-radar transmits a high frequency signal whose frequency increases linearly during the measurement phase (called the frequency sweep). The signal is emitted, reflected from the measuring surface and received with a time delay, t. Delay time, t=2d/c, where d is the distance to the product surface and c is the speed of light in the gas above the product. For further signal processing the difference Δf is calculated from the actual transmit frequency and the receive frequency. The difference is directly proportional to the distance. A large frequency difference corresponds to a large distance and vice versa. The frequency difference Δf is transformed via a Fourier transformation (FFT) into a frequency spectrum and then the distance is calculated from the spectrum. The level results from the difference b...

 Alternative to Pressure Transmitters Leg Compensation An alternative to using a compensating leg to subtract gas pressure inside an enclosed vessel is to simply use a second pressure transmitter and electronically subtract the two pressures in a computing device: This approach enjoys the distinct advantage of avoiding a potentially wet compensating leg, but suffers the disadvantages of extra cost and greater error due to the potential calibration drift of two transmitters rather than just one. Such a system is also impractical in applications where the gas pressure is substantial compared to the hydrostatic (elevation head) pressure. If we add a third pressure transmitter to this system, located a known distance (x) above the bottom transmitter, we have all the pieces necessary for what is called a tank expert system. These systems are used on large storage tanks operating at or near atmospheric pressure, and have the ability to measure infer liquid height, liquid density, total l...

 An Orifice Meter is basically a type of flow meter used to measure the rate of flow of Liquid or Gas, especially Steam, using the Differential Pressure Measurement principle. It is mainly used for robust applications as it is known for its durability and is very economical. As the name implies, it consists of an Orifice Plate which is the basic element of the instrument. When this Orifice Plate is placed in a line, a differential pressure is developed across the Orifice Plate. This pressure drop is linear and is in direct proportion to the flow-rate of the liquid or gas. Since there is a drop in pressure, just like Turbine Flow meter, hence it is used where a drop in pressure or head loss is permissible. An orifice meter is a conduit and a restriction to create a pressure drop. A nozzle, venturi or thin sharp edged orifice can be used as the flow restriction. In order to use any of these devices for measurement it is necessary to empirically calibrate them. That is, pass a known v...

 Even though a Coriolis flowmeter inherently measures mass flow rate, the continuous measurement of fluid density allows the meter to calculate volumetric flow rate if this is the preferred means of expressing fluid flow. The relationship between mass flow (W), volumetric flow (Q), and mass density (ρ) is quite simple: All the flowmeter’s computer must do to output a volumetric flow measurement is take the mass flow measurement value and divide that by the fluid’s measured density. A simple exercise in dimensional analysis (performed with metric units of measurement) validates this concept for both forms of the equation shown above: Coriolis mass flowmeters are very accurate and dependable. They are also completely immune to swirl and other fluid disturbances, which means they may be located nearly anywhere in a piping system with no need at all for straight-run pipe lengths upstream or downstream of the meter. Their natural ability to measure true mass flow, along with their chara...

 DP Flow Transmitter Re-Range : This tool is used to calculate the DP Flow transmitter revised flow with the following inputs: Existing DP, Existing Flow & Revised DP. This tool is primarily used for orifice based flow meters. Also useful for flow transmitters which works on Differential Pressure applications. Generally we calibrate our transmitter as per the datasheet of orifice. But sometimes the measured DP of transmitter will be out of range or more than maximum scale of DP then we have to re-range the DP flow transmitter. For these applications we use the below mentioned formula to calculate the maximum flow of transmitter. DP Flow Transmitter Re-Ranging This calculation tool is used to calculate the revised flow range of a DP Flow transmitter. The formula for calculating the DP Flow Transmitter Re-Range value. Where, Existing DP    = DP value as per orifice datasheet Existing Flow  =  Flow value as per orifice datasheet Revised DP    =  ...

 Variable area flow meters operate at a constant delta pressure (Δp) and the area changes with the flowrate. The area will increase as the flowrate through the meter increases to preserve a constant Delta Pressure (Δp). Variable Area Flow Meters The most common design of variable area meter is the cone-and-float type, which is also known as a rotameter. The basic design of a variable area meter is a tapered tube (usually glass) containing a self-centring float that is pushed up by the flow and pulled down by gravity. At higher flow rates the float rises to increase the area between the tube and the float and maintain a constant Δp. The flowrate is determined from how far the float has risen up the tube: there are graduations on the side of the tube.Variable area meters are widely used for metering gas but different types are available for a variety of different fluids. A buoyancy correction term is required for liquids and dense fluids. Variable area flowmeters are very simple yet ...

A vortex flow meter works based on the principle of ‘Karman vortex street’ demonstrated in the below figure. This principle essentially means that when an obstruction is placed in path of a flow, it can produce a series a vortices alternating from each side of the obstruction.The frequency of alternating of these vortices is proportional to the flow rate being obstructed. Principle of Vortex Flowmeter  The vortex type flow meter uses a small rod called ‘shredder bar’ or ‘bluff bar’ to shred vortices and these vortices produced is directly proportional to flow rate. These vortices can be measured using a pressure sensor and it calculates proportional flow rate. In some applications different type of sensor may use in place of pressure sensor.

 Electromagnetic Flow Meters, simply known as mag flow meter is a volumetric flow meter which is ideally used for waste water applications and other applications that experience low pressure drop and with appropriate liquid conductivity required. The device doesn’t have any moving parts and cannot work with hydrocarbons and distilled water. Mag flow meters are also easy to maintain. Electromagnetic Flow Meters Principle of Magnetic Flow Meter Based on Faraday’s Law Magnetic flow meters works based on Faraday’s Law of Electromagnetic Induction. According to this principle, when a conductive medium passes through a magnetic field B, a voltage E is generated which is proportional to the velocity v of the medium, the density of the magnetic field and the length of the conductor. In a magnetic flow meter, a current is applied to wire coils mounted within or outside the meter body to generate a magnetic field. The liquid flowing through the pipe acts as the conductor and this induces a v...

 A magnetic flow meter (mag meter, electromagnetic flowmeter) is a transducer that measures fluid flow by the voltage induced across the liquid by its flow through a magnetic field. A magnetic field is applied to the metering tube, which results in a potential difference proportional to the flow velocity perpendicular to the flux lines. The physical principle at work is electromagnetic induction. The magnetic flow meter requires a conducting fluid, for example, water that contains ions, and an electrical insulating pipe surface, for example, a rubber-lined steel tube. Magnetic Flow Meter Animation The Two Blue dots in the animation indicates electrodes. The Copper coils (red blocks – magnets) on top & bottom of the instrument are electro-magnets used to generate a magnetic field. When there is no fluid flow then the induced voltage between electrodes is Zero. When a fluid flows through the magnetic field, the two electrodes pick up the voltage and it is proportional to fluid fl...

 Coriolis Meter is a Direct type Flow Measurement instrument and Measures the Mass Flow. When there is no flow through the tubes then the tubes vibrate at a resonant frequency. When there is a flow through the tubes then depends on the flow & its mass the tubes vibration will change. The change in vibration is measured and it is proportional to Mass Flow. Coriolis Meter A mass flow meter, also known as an inertial flow meter is a device that measures mass flow rate of a fluid traveling through a tube. The mass flow rate is the mass of the fluid traveling past a fixed point per unit time. The mass flow meter does not measure the volume per unit time (e.g., cubic meters per second) passing through the device; it measures the mass per unit time (e.g., kilograms per second) flowing through the device. Volumetric flow rate is the mass flow rate divided by the fluid density. If the density is constant, then the relationship is simple. If the fluid has varying density, then the relati...