The downstream bore of the orifice is chamfered at 40 to provide an effective orifice plate thickness of 0. On the other hand, the venturi meter has a lower energy loss compared with a flow nozzle. Advantages and disadvantages of orifice and venturi meter. A vortex meter primary flow element produces a series of oscillations of pressure. Difference between venturi meter and orifice meter. Bengtson orifice and venturi pipe flow meters for liquid. Pdf experimental investigation of the installation effects. Different types of flow meters are available for different application and depending upon the. Discharge coefficient performance of venturi, standard. To find the coefficient of discharge for orifice meter. Cebu city, 6000 philippines this experiment aims to be calibrate both the venture apparatus and the orifice apparatus. Gaskets are provided to seal both sides of the plate. Flow measurement in pipes and ducts cedengineering. The tables show the air flow in scfh in hundreds and the corresponding pressure drop in inches of water column.
The turndown ratio tr for an orifice meter with maximum flow of 12 kgs and a minimum flow of 3 kgs can be calculated as. Generally, the physical property generated by the primary flow element is more convenient to measure than the flow itself. The venturi meter is a piping component and should be handled with th e same safety precautions. Orifice flange unions consist of two ansirated flanges usually weldneck, but slipon or threaded types are also available. Orifice meter free download as powerpoint presentation. Excel formulas use the ideal gas law to calculate the density of a gas for known gas molecular weight, temperature and pressure. It uses the same principle as a venturi nozzle, namely bernoullis principle which states that there is a. Orifice meter definition of orifice meter by the free. As the name implies, it consists of an orifice plate which is the basic element of the instrument. This meters design provides longer lasting accuracy and lower permanent pressure loss than orifice type meters, reducing maintenance and operating costs. Venturi meter and orifice meter are the commonly used flow meters for measuring massvolumetric flow rate or velocity of the flowing fluid.
Orifice meter definition and meaning collins english. This article contains three example excel templates that can be downloaded. If the meter is to be removed from the line for any reason, depressurize and drain the pipe line. Schematic diagram of orifice plate the orifice flow meter consists of a 20mm bore tube with an orifice of 12mm. The mass and volumetric flow rates did not differ by much, as seen on the. Determine that the meter is installed with the arrow on the nameplate and on the meter body pointing in the direction of the flow. Orifice 1 to determine the coefficient cd of an orifice meter by comparing the measured flow rate. Bsen 3310 lab 2calibration of orifice flow meter and. The reduction of the cross section of the flowing stream in passing through the orifice increases the velocity head at the expense of the pressure head, and the reduction in pressure between the taps is measured by a manometer. Numerical simulations for multihole orifice flow meter.
As the name suggests, a flow meter is a device or an instrument used to measure linear, nonlinear, mass or volumetric flow rate of a liquid or a gas. The lengths of straight pipe required upstream and downstream of a venturi meter for accurate flow measurement are given in iso 51671. Yamamoto department of chemical engineering, college of engineering and architecture, cebu institute of technology university n. It is determined by measuring the rise of liquid in a tube. Department of mechanical engineering calibration of an orifice meter objective. The basic equation for the orifice meter is obtained by writing the bernouli equation for the. Nov 25, 2016 principal of orific meter the principle of the orifice meter is identical with that of the venturi meter. The major difference between venturi and orifice meter is the time taken for water collection in measuring tank size of tank minimum 60 ltrs. Offer very little pressure drop from which 60% to 65% is recovered. Orifice flow meter s are ideal for measuring air and gas flows in combustion systems. A free powerpoint ppt presentation displayed as a flash slide show on id.
For these reasons it is widely used, particularly for large volume liquid and gas flows. Orifice flange unions consist of two ansirated flanges usually. Designs, materials, weights and performance ratings are approimate and subect to change without notice. The inlet diameter equals d 26 mm and the throat diameter d 16 mm. Singh presented the experimental and numerical study on the flow meter with singlehole orifice and multihole orifice, it is observed that the discharge coefficient of multihole orifice is. It is mainly used for robust applications as it is known for its durability and is very economical.
It is used to measure the velocity of flow at the required point in a pipe. Furthermore, we will use the data extracted from our experiment to determine the discharge coefficients of those devices. Following table summarizes difference between venturi meter and orifice meter. Different types of flow meters are available for different application and depending upon the requirement, a careful selection of flow meter is made. Note that at the throat where the velocity is the greatest, the pressure is least. In general a orifice plates has turndown ratio between 3. Determination of coefficient of discharge for flow meters. Venturi flow meters, commonly just referred to as venturi meters, are used to measure the flow rate of fluids in a wide range of applications. The expansibility factor is applied to the flow equation in the same way as the discharge coefficient. Venturi and orifice laboratory 3 venturi meter and. Select the orifice by either pressure drop or by flow. Orifice meter fluid dynamics dynamics mechanics free. Pharaohs and that the romans used orifices to meter water. Venturi meter presents a costlier method to measure the rate flow of fluid through the pipe.
A venturi tube is a device which consists of a convergent inlet connected to a cylindrical throat which is in turn connected to a conical expanding section called the divergent exit. Several graphs demonstrating the varying relationships and. Moreover, their acquisition and operation costs are smaller than the ones verified for other flow meters venturi, flowmeter. Orifice coefficients are smaller and more variable than those for the venturi and the quantitative treatment of the orifice meter is modified accordingly. Flow measurement with orifice,venturi and rotameter engi. Pdf flow through a venturi meter orifice rotameter emmanuel. However, the same principle can be exploited with only minimal pressure loss with the use of a venturi meter. The pressure along the meter is obtained using the 11 pressure taps at the locations shown on the diagram. Flow measurement orifice meter 1 flow measurement orifice meter by. The volumetric flowrate, q, of a given fluid through an orifice nozzle flow meter is proportional to the square root of the pressure drop across the meter.
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. The standard orifice plate does not follow the general trend in the discharge coefficient curve that the other flow meters do. To find the coefficient of discharge for venturi meter. Orifice meter and pitot tube mechanical engineering. These are shorter than those required for an orifice plate by a factor which can be as large as 9. A simple live diagnostics plot is shown in the control room. A dp diagnostics venturi flow meter under a customers fat.
However this meter is relatively complex to construct and hence expensive. Energy losses are less in a venturi meter whereas energy losses. If the velocity at any point decreases, the pressure at that point increases due to the conservation of the kinetic energy into pressure energy. If a pump forces the liquid through a tube connected to a system consisting of a venturi to increase the liquid speed the diameter decreases, a short piece of tube with a small hole in it, and last a venturi that decreases speed so the pipe gets wider again, the gas will be sucked in through the small hole because of changes in pressure. This is a typical turndown ratio for a orifice plate. What is the difference between venturimeter and orificemeter. One of the disadvantages of orifice meters is the large irreversible pressure loss across the orifice, which results in substantial pumping costs in case of large diameter pipes. These results show shifts in orifice meter discharge coefficients that are.
How does the pressure change as air flows through a venturi meter. It is a cheaper device as compared to venturimeter. Tr 12 kgs 3 kgs 4 normally expressed as turndown ratio of 4. The orifice flange union ofu was the only orifice plate holder available until the invention of the orifice fitting or meter. Pdf numerical methodology for orifice meter calibration. The simplest and most common device for measuring flow rate in a pipe is an orifice meter. Flow measurement with orifice,venturi and rotameter engi tube. This implies that the curves accurately represent the data points. Excel templates can be downloaded to make venturi meter and orifice flow meter calculations in u. Orifice meter orifice meter is a device used to measure volumetric flow rate. While plumbing applications tend to be the most popular, venturi meters can be used in applications that involve water, propane, oil. Nov, 2017 flow measuring devices venturi meter, orifice meter. Meters should have at least 10 pipe diameters of smooth, clean, straight pipe upstream and downstream for accurate readings.
Fm 308 flow measurement by venturi and orifice meter. Use excel formulas for orifice, venturi meter and ideal. A schematic of the venturi meter is shown on the diagram at the end of the procedure. The principle of the method of measurement is based on the installation of a venturi tube into a pipeline in which a fluid is running full. Pdf orifice meters are mechanical devices used to measure gases and. It uses bernoullis principle as used by venturimeter. It may be installed in pipeline with a minimum of trouble and expense. Flow through venturi meter background and theory introduction flow meters are used in the industry to measure the volumetric flow rate of fluids of the modern venturi meter in 1886 by clemons herschel. Information is also given on using squareedged orifice plate.
Chhorlyheang chres purpose the purpose of this lab is to understand behavior the flow through a venturi meter and an orifice plate by examining the effect of discharge. Move meter with slings or strapping appropriate for the weight and geometry of the meter. The water flow rate can be adjusted using the valves on the hydraulics bench. The diagnostic system multiplies the meters capability. Flow nozzles and venturi tubes are primary rate devices which will handle about. Made by faculty at the university of colorado boulder department of. The venturi flow meter can be built to meet the highest pressure and temperature specifications often limited in other flow meter technologies. Water from the hydraulic bench enters the equipment through a venturi meter.
Fm 308 flow measurement by venturi and orifice meter objectives. Moreover, the orifice plate shall be kept clean at all times and free from accumulation of. The original orifice plate holding device was the orifice flange union figure 1. The mass and volumetric flow rates did not differ by much, as seen on the graphs. For example, an orifice plate produces a pressure drop that is a function of the square of the volume rate of flow through the orifice. It works on the same principle as that of venturimeter. Experimental investigation of the installation effects on the venturi flow meter performance. Advantages and disadvantages of orifice and venturi meter are listed below.
The venturi flow meters can be stored indefinitely indoors in a clean noncorrosive environment. Pdf experimental investigation of the installation. Sep 19, 2011 the turndown ratio tr for an orifice meter with maximum flow of 12 kgs and a minimum flow of 3 kgs can be calculated as. Energy losses through venturi, orifice, and rotameter. Theory a venturi meter is a device used to measure the flow speed of a fluid in a pipe. Various forms of construction of a venturi meter are employed, depending on size, but all are. Storage requirements cast iron, ductile iron, and fabricated pressure vessel venturi flow meters indoor storage. This white paper provides an overview of orifice meter technology. In simplest form, the pitot tube consists of a glass tube, bent at right. It consists of flat circular plate which has a circular hole, in concentric with the pipe.
Orifice meter the venturi meter described earlier is a reliable flowmeasuring device. Made by faculty at the university of colorado boulder department of chemical. Venturi meter a cross section of the brass venturi meter tested is shown in figure 3. Calibration of venturi and orifice meters hirizza junko m. Energy losses through venturi, orifice, and rotameter flowmeters. Each has built in excel formulas to calculate unknowns like the pipe flow. The two most important factors that influence the reading of an orifice meter are the size of the orifice and the diameter of the pipe which it is fitted into. This also work on the same principle as that of venturimeter. The orifice is small plates and easy to installremove.
Bsen 3310 lab 2calibration of orifice flow meter and venturi. Venturi flow meter installation and operation manual. Orifice meter definition and meaning collins english dictionary. Pressure field through the venturi meter a downstream pressure tap allows 3 dps to be read. Fm 308 flow measurement by venturi and orifice meter chemical. Jul 23, 2016 the orifice meter is a device cheaper than venturimeter used for measuring the discharge of the liquid flowing through a pipe. The inlet section is a standard asme longradius nozzle with a throat diameter dv of 0. At the throat, the area is reduce from a to a and the velocity is increased from v to v.
I have read about pressure recovery for both meters and found that there is always a permanent pressurehead loss dependent on the area ratio for orifice while for venturi, fluid slows down in a cone with smaller angle where kinetic energy is converted back to. Thus, qk h where is the meter calibration constant and. Formulation and validation in multiphase flow conditions. Orifice meter presents a cheaper method to measure the rate of flow through the pipe. Dp diagnostics supplies a unique, powerful, industrially proven, patent pending diagnostics system. A venturi can also be used to mix a liquid with a gas. The major difference between venturi and orifice meter is the time taken for water collection in measuring tank size of tank minimum 60 ltrs is more in venturimeter when compared with orificemeter. Most modern browsers have builtin pdf readers if you have problems opening this file in your browser, check your browsers or computer systems settings. I have this misconception about pressure drop of venturi meter and orifice meter. Difference between venturi meter and orifice meter venturi. Ansery orifice meter it may be installed in pipeline with a minimum of trouble and expense orifice meter orifice meter.
Venturi meter vs orifice meter student cheresources. The pitot tube is a small open tube bent at right angle. Flow measurement using venturimeter, orifice meter, variable area flow meter like rotameter 2. To determine the coefficient of discharge of the orifice meter 1.
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