TILI Automation

 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...

 Impeller Flow Sensor probes are equipped with light weight helical impellers mounted on double sapphire bearings. The impellers contain magnets which actuate Hall-effect switches within the probe to detect impeller rotation. The impeller rotation is proportional to flow rate. Impeller Flow Sensor

 A  flow transmitter  is  ranged  0  to  350  GPM,   4-20  mA  output,   direct-responding. Calculate  the current signal value at a flow rate  of 204 GPM. We are solving this problem using standard 4-20mA conversion Formula. Click here for formula One  way  we could  solve for the amount  of signal  current  is to convert  the flow value  of 204 . GPM  into a ratio of the flowmeter’s full-flow value,  then apply  the same  formula  we used  in the previous example relating percentage to milliamps.  Converting the flow rate into a “per unit” ratio is a matter of simple division, since the flow measurement range is zero-based: Therefore,  the transmitter should output a PV signal of 13.3 mA at a flow rate of 204 GPM. Flow Transmitter Calculations An alternative approach is to set  up  a linear  equation specifically...

 A rotameter is a device that measures the flow rate of liquid or gas in a closed tube. Rotameter It belongs to a class of meters called variable area meters, which measure flow rate by allowing the cross-sectional area the fluid travels through, to vary, causing a measurable effect. A rotameter consists of a tapered tube, typically made of glass with a ‘float’, made either of anodized aluminum or a ceramic, actually a shaped weight, inside that is pushed up by the drag force of the flow and pulled down by gravity. The drag force for a given fluid and float cross section is a function of flow speed squared only. A higher volumetric flow rate through a given area increases flow speed and drag force, so the float will be pushed upwards. However, as the inside of the rotameter is cone shaped (widens), the area around the float through which the medium flows increases, the flow speed and drag force decrease until there is mechanical equilibrium with the float’s weight. Floats are made ...

 A vortex flow meter comprising: a flow sensor operable to sense pressure variations due to vortex shedding of a fluid in a passage and to convert the pressure variations to a flow sensor signal, in the form of an electrical signal; and a signal processor operable to receive the flow sensor signal and to generate an output signal corresponding to the pressure variations due to vortex-shedding of the fluid in the passage. Vortex Flow meter Animation When the medium flows through the Bluff body at a certain speed,an alternately arranged vortex belt is generated behind the sides of the Bluff body, called the “von Kármán vortex“. Since both sides of the vortex generator alternately generate the vortex,the pressure pulsation is generated on both sides of the generator,which makes the detector produce alternating stress. The piezoelectric element encapsulated in the detection probe body generates an alternating charge signal with the same frequency as the vortex, under the action of alte...

 This article discusses the differences between the orifice and the restriction orifice of the physical form, functionality and applications in the oil and gas facilities Preliminary Do you want to measure the flow of a fluid or if you want to reduce the pressure of a fluid drastically and permanently? Both of these can be done by objects whose names both contain the word Orifice, the first and the second Orifice Restriction Orifice. Generally, the orifice has the shape as a plate that has a hole in the middle. Examples of the orifice as shown below: Approximately what are the differences between the Orifice for flow meter and Restriction Orifice? Let us examine the figure below is an example of the image for the flow meter and Restriction Orifice Orifice. The shape of the orifice flow meter and orifice above restriction is a common form and in general there is a difference in the profile of the hole of the second orifice. Orifice flow meter generally have a profile for the first p...

 Turbine Flow Meters Troubleshooting 1. What is a turbine flow meter? How and when is it used? A turbine flow meter is a liquid/gas velocity measurement device. The turbine flow meter contains a free spinning turbine rotor that turns at a speed that is proportional to the flow velocity. 2. Can liquid meters measure gas and vice versa? No – gas in a liquid meter will cause the meter to read high and can cause catastrophic failures. Liquid going through a gas meter will cause erroneous indications of the gas flow rate and can cause meter damage. 3. How do you size gas turbines? With gas turbines, flowing pressure and temperature are taken into account, as well as the flow rate. 4. What is the maximum working pressure? The maximum working pressure of meters is determined by the end connections. 5. What size meter will I need for a certain size pipe? Meter size depends on the flow rate being metered, not pipe size. Most oilfield applications oversize the pipe so the meter flow rate siz...

 An orifice meter is a conduit and a restriction to create a pressure drop. An hour glass is a form of orifice. 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 volume through the meter and note the reading in order to provide a standard for measuring other quantities. Due to the ease of duplicating and the simple construction, the thin sharp edged orifice has been adopted as a standard and extensive calibration work has been done so that it is widely accepted as a standard means of measuring fluids. Provided the standard mechanics of construction are followed no further calibration is required. An orifice in a pipeline is shown in figure with a manometer for measuring the drop in pressure (differential) as the fluid passes through the orifice. The minimum cross sectional area of the jet is known as the “vena-contracta.” Orifice...

 Why Orifice Plate is having a 3:1 Turndown Ratio in Practice? It is a general practice in the differential type flow meter, using flow orifice plate as a flow element, to limit the using in a 3:1 to 4:1 turndown ratio. Where this general practice comes from? Orifice Plate Turndown ratio The limitation of the DP type flow meter using orifice isn’t comes from the beta ratio limitation of the flow orifice plate nor any other flow orifice plate dimension. The limitation is comes from the error reading caused by the un-linear relationship between the differential pressure across flow orifice plate and the calculated flow rate. In simplify concept we can calculate the orifice flow rate by: Qm = C x (Differential Pressure)^0.5 Where, Qm : Flow rate C : Meter Constant Differential Pressure : differential pressure across flow orifice plate From the above equation we know that the flow rate is proportional to the square root of the differential pressure. This un-linear relation produces a s...