mechanical flow meter

The shaft passes between the metering tube and the register section through a mechanical stuff Optical or magnetic sensors are used to encode a pulse train proportional to the rotational speed of the helical gears. Hot water units are available up to 250°F. Accuracy of ±0.1% of actual rate (AR) is normal, and larger size meters on higher viscosity services can achieve accuracy to within 0.05% of rate. Because pressure drop increases with the square of flow rate, reducing the meter to the next smaller size will raise the pressure drop considerably. Meters with rubber discs give better accuracy than metal discs due to the better sealing they provide. They are often used in large diameter pipelines where it would be cost-prohibitive to install a full size meter. Therefore, the pressure drop across the meter limits the allowable maximum flow in high viscosity service. The meter consists of four chambers: the two diaphragm chambers on the inlet and outlet sides and the inlet and outlet chambers of the meter body. The best attainable accuracy is about ±0.2% or rate. Nutating disc meters are the most common PD meters. © 2009 - 2020 instrumentationtoolbox.com. Because at maximum flow the pressure drop through the meter should not exceed 30 psid, the maximum rated flow through the meter is reduced as the fluid viscosity increases. Most paddlewheel meters have flat-bladed rotors and are inherently bi-directional. Because there are minor inconsistencies in the manufacturing process, all turbine flow meters are calibrated prior to shipment. On low density fluids (SG < 0.7), the minimum flow rate is increased due to the reduced torque, but the meter's accuracy usually is not affected. They are a type of variable area meter and display flowrate using a floater that lines up with a measurement printed on the tube. Check valves (or, on critical applications, double check valves) are selected to protect against backflow. Flow Meters and Environmental Sensors for Precision Fluid Measurement. Dual-rotor liquid turbines increase the operating range in small line size (under 2 in) applications. }, Copyright 2003 - 2019 OMEGA Engineering is a subsidiary of Spectris plc. Rotors are typically made of a non-magnetic material, like polypropylene, Ryton, or PVDF (Kynar). ), ( The two rotors turn in opposite directions. Most turbine meters are designed for maximum velocities of 30 ft/sec. Accuracy is not affected by pulsating flow unless it entrains air or gas in the fluid. The batching controller is set with the desired target volume and, when its totalizer has counted down to zero, it terminates the batch. The rotor and bearing materials are selected to match the process fluid and the service. 11 These meters must meet American Water Works Association (AWWA) standards for accuracy. Mechanical Water Flow Meters. They are used as residential water meters around the world. ), ( range 10cm/sec (1/5 knot) to 7.9m/sec approximately (15 knots) Products. Accuracy ranges from ±0.5 % AR for viscous fluids to ±2% AR for nonviscous applications. It is now possible to include complex linearization functions in the preamplifier of a turbine flow meter to reduce these nonlinearities. Because of the intermittent use patterns of residential users, this corresponds to recalibrating 5/8 x 3/4 in residential water meters after they have metered 5 million gallons. These meters are available in 1/10-in to 6-in sizes and can handle pressures to 3,000 psig and temperatures to 400°F. The use of capacitively coupled pick-ups or Hall-effect sensors extends the range of paddlewheel meters into the low-flow velocity region of 0.3 ft/sec. Totalizers measure the cumulative flow volume. Propeller meters are commonly used in large diameter (over 4 in) irrigation and water distribution systems. The tubing can be silicone-rubber or, if a more corrosion-resistant material is desired, PTFE tubing. If the amount of suspended solids exceeds 100 mg/l of +75 micron size, a flushing y-strainer or a motorized cartridge filter must be installed at least 20 diameters of straight run upstream of the flow meter. Also, the maximum flow through this meter is less than for the same size oscillatory piston or nutating disc meter. It consists of a multi-bladed rotor mounted at right angles to the flow and suspended in the fluid stream on a free-running bearing. The minimum upstream straight pipe-run requirement is 20 pipe diameters. The lubricating characteristics of the process fluid also affect the turndown of an oval gear meter. Rotameters require no external power or fuel, as they use the force of the fluid and gravity to measure flowrate. Density changes do not greatly affect turbine meters. In these turbine flow meters, very small magnets are embedded in the tips of the rotor blades. The repeatability is from ±0.2% to ±0.02% over the linear range. 25 diameters for a partially open valve; and Their primary trade-off is low cost and low accuracy (Figure 3-11A). Turbine meters also can be damaged by solids entrained in the fluid. Products. In the inductance pick-up, the permanent magnet is embedded in the rotor, or the blades of the rotor are made of permanently magnetized material (Figure 3-8B). Standard Mechanical Flowmeters Basic vane-operated flowmeters provide inexpensive flow monitoring for processing and troubleshooting. 3.4 out of 5 stars 22. The turbine is suspended by a bearing between two hanger assemblies that also serve to condition the flow. Dwyer water meters … This approach can provide high accuracy (up to ±0.01% of rate) but requires removing the flow meter from service. More recently, the water distribution industry has adopted a magnetic drive as an improvement over high maintenance mechanical-drive turbine meters. If you want to learn more about positive displacement flow meter, read this article. Figure 3-5: Click on figure to enlarge. Because of the close tolerances required to seal the piston and to reduce slippage, these meters require regular maintenance. The outputs of reluctance and inductive pick-up coils are continuous sine waves with the pulse train's frequency proportional to the flow rate. The piston is guided by a control roller within the measuring chamber, and the motion of the piston is transferred to a follower magnet which is external to the flowstream. ), ( Gas turbine meters are available from 2" to 12" and with flow ratings up to 150,000 ft3/hr. 22 Instead of pick-up coils, Hall-effect transistors also can be used. In the rotating lobe design, two impellers rotate in opposite directions within the ovoid housing (Figure 3-3B). Viscosity affects the accuracy and linearity of turbine meters. NPT 1/2" to 2" Mechanical … Mechanical wear, straightening, and conditioning requirements are the same as for turbine meters. In these units, the passage of magnets embedded in the lobes of the rotating impellers is sensed by proximity switches (usually Hall-effect detectors) mounted external to the flow chamber. In many operations, especially in the petroleum industry, it is difficult or impossible to remove a flow- meter from service for calibration. Rotating vane meters (Figure 3-1B) have spring-loaded vanes that entrap increments of liquid between the eccentrically mounted rotor and the casing. The piston can either be directly coupled to the diaphragm or can force a hydraulic oil to drive the diaphragm. The forces required to make the helices rotate are relatively small and therefore, in comparison to other PD meters, the pressure drop is relatively low. When operating at elevated gas pressures (1,400 psig), a rangeability of 100:1 can be obtained in larger size meters. in the coil (Figure 3-8A). Reciprocating piston meters are probably the oldest PD meter designs. These Fuel Meter are exceptionally intended to quantify quick … flowmeter, digital, mechanical, w/standard rotor response with the standard rotor-threshold approximately 10cm/sec (1/5 knot). Turbine meters should be sized so that the expected average flow is between 60% and 75% of the maximum capacity of the meter. As with all positive displacement pumps, piston pumps generate a pulsating flow. In order to reduce this straight-run requirement, straightening vanes are installed. This has made them extre… 1″ Digital Turbine Flow Meter,Gas Oil Fuel Flowmeter,Pump Flow Meter ，Diesel Fuel Flow Meter,High Accuracy,for Measure Diesel, Kerosene, Gasoline, etc. The signal output from a Hall-effect sensor is a square wave pulse train, at a frequency proportional to the volumetric flowrate. These meters can be very accurate if slippage between the housing and the gears is kept small. Vapor separators are usually included, to prevent vapor lock. Mechanical Flow Metering ELSTER offers a wide range of different measurement devices for measurement of gas volume and gas flow. The calibration for the new flow rating (QN) is obtained by multiplying the meter's flow rating for natural gas (QC) by the square root of the ratio of the specific gravities of natural gas (0.6) and the new gas (SGN): High-precision gas meters are usually a hybrid combining a standard PD meter and a motor drive that eliminates the pressure drop across the meter. Varying the diameter and the shape of the jet orifice matches the required flow range and provides a flow meter that is accurate to 1% FS and has a rangeability of 100:1. These turbine meters use a gear train to convert the rotation of the rotor into the rotation of a vertical shaft. Standard C701 provides for two classes (Class I and Class II) of turbine flow meters. Mechanical Flowmeter Flowmeters 396 products A liquid flow meter from Grainger can help easily monitor liquid flow rates for water, fuels, viscous fluids and more. Flow Meters. Turbine flowmeters are commonly used to track total fuel gas (e.g. This increases accuracy at low flows and under varying viscosity conditions (Figure 3-6B). Cold water service units are temperature-limited to 120°F. Class II turbine meters must register between 98.5-101.5% of actual rate. PD gas meters operate by counting the number of entrapped volumes of gas passed, similar to the way PD meters operate on liquids. In industrial applications, however, these meters are likely to pass this threshold much sooner. On the measuring chamber side, the vertical shaft turns a magnet instead of a gear. Mechanical Flow Meters. AWWA Standard C-704 sets the accuracy criterion for propeller meters at 2% of reading. The piston is also cylindrical and is punctured by numerous openings to allow free flow on both sides of the piston and the post (Figure 3-2A). Single jet flow meter and Paddle wheel flow meter use a mechanism similar to turbine flow meters and consist of a simple impeller wheel with radial vanes, impinged upon by a single jet. Invented by Reinhard Woltman in the 18th century, the turbine flow meter is an accurate and reliable flow meter for both liquids and gases. Low-flow meters (usually smaller than 1 in.) 12 Transducer Technology, established in 1983, are importers and distributors of a comprehensive range of electronic measuring … A typical configuration consists of a single diaphragm, a chamber, and suction and discharge check valves to prevent backflow. Totalizers measure the cumulative flow volume. Small amounts of air entrainment (100 mg/l or less) will make the meter read only a bit high, while large quantities can destroy the rotor. All meters with moving parts require periodic testing, recalibration and repair, because wear increases the clearances. Figure 3-2: Click on figure to enlarge. Upper limit on viscosity is 10,000 centipoise. At low flow, the output (the height of the voltage pulse) may be on the order of 20 mV peak-to-peak. These meters are usually smaller (available in sizes down to 1/10-in diameter) and are used for measuring very low flows of viscous liquids. Figure 3-9: Click on figure to enlarge. They are available with multiple pistons, double-acting pistons, or rotary pistons. Recalibration can be done either in a laboratory or on line using a prover. 6 natural gas) consumption used by a commercial or industrial facility for billing. Therefore, the distance between the pickup and associated display electronics or preamplifier must be short. Shunt flow meters are used in gas and steam service. Pressure and temperature limits depend on the materials of construction and can be as high as 350°F and 1,000 psig. Typical accuracy of an insertion turbine meter is 1% FS, and the minimum flow velocity is about 0.2 ft/sec. The disadvantage of m… For smaller pipes (1/2" to 3"), these meters are available only with a fixed insertion depth, while for larger pipe sizes (4" to 48") adjustable insertion depths are available. The number of pulses per unit volume is called the meter's K-factor. The wetted parts such as the disc and spindle are usually bronze, rubber, aluminum, neoprene, Buna-N, or a fluoroelastomer such as FKM. ambient temperatures and at up to 30 psig pressures, this meter is claimed to provide accuracy to within 0.25% of reading over a 50:1 range and 0.5% over a 100:1 range. Ultrasonic Bulk Water Meters. Diaphragm gas meters most often are used to measure the flow of natural gas, especially in metering consumption by households. Because of the close tolerances of the piston and cylinder sleeve, a flushing mechanism must be provided in abrasive applications. Oscillating piston flow meters are available in 1/2-in to 3-in sizes, and can generally be used between 100 and 150 psig. All Rights Reserved. This permits a completely sealed register to be used with a mechanical drive mechanism. 19 Repeatability is generally not greatly affected by changes in viscosity, and turbine meters often are used to control the flow of viscous fluids. These meters can be made out of a variety of metals, including stainless steel, and corrosion-resistant plastics such as PVDF (Kynar). However, the presence of any of the following obstructions upstream would necessitate that there be more than 15 diameters of upstream straight-pipe runs While PD meters are operated by the kinetic energy of the flowing fluid, metering pumps (described only briefly in this article) determine the flow rate while also adding kinetic energy to the fluid. $36.59. Errors were found with the address you provided. Figure 3-8: Click on figure to enlarge. This action alternately empties and fills the four chambers. they are machined from stainless steel hexagonal barstock. Piston pumps deliver a fixed volume of liquid with each "out" stroke and a fixed volume enters the chamber on each "in" stroke (Figure 3-5A). If the range of 10:1 is insufficient, some turbine flow- meters can provide up to 100:1 turndowns if accuracy is de-rated to 1% of full scale (FS). This type of prover consists of a calibrated chamber equipped with a barrier piston (Figure 3-7). Oscillating piston flow meters typically are used in viscous fluid services such as oil metering on engine test stands where turndown is not critical (Figure 3-2). ), ( A liquid flow meter from Grainger can help easily monitor liquid flow rates for water, fuels, viscous fluids and more. In the reluctance pick-up, the coil is a permanent magnet and the turbine blades are made of a material attracted to magnets. This design is claimed to provide 0.25% of rate accuracy over a 50:1 range at operating pressures of up to 150 psig. Because they are very sensitive to the velocity profile of the flowing stream, they must be profiled at several points across the flow path. Provers are available for bench-top use, for mounting in truck-beds, on trailers, or in-line. Available are local and remote inidication models. have a small jet orifice that projects the fluid onto a Pelton wheel. The measurement chamber is cylindrical with a partition plate separating its inlet port from its outlet. Each pulse represents a discrete volume of liquid. Turbine meters have a typical nonlinearity (the turbine meter hump, shown in Figure 3-9) in the lower 25-30% of their range. Variable Area Meters Provide precise visual indication of rates of flow of air, liquids and industrial gases. Flow velocities under 1 ft/sec can be insufficient, while velocities in excess of 10 ft/sec can result in excessive wear. Gas systems are recalibrated against a bell-jar prover--a calibrated cylindrical bell, liquid sealed in a tank. The frequency of the resulting pulse train is a measure of flow rate, while the total number of pulses gives the size of the batch. thick fluids such as glues and very viscous polymers. The primary difference is that gases are compressible. Batching flow computers are readily available, as are analog and intelligent digital transmitters. Digital Turbine Flow Meter,1″ Digital LCD Display with NPT Counter Gas Oil Fuel Flowmeter,Pump Flow Meter,Diesel Fuel Flow Meter for Measure Diesel, Kerosene, Gasoline. Higher accuracy can be achieved by calibrating the meter and by lowering its range. The rotation of the vanes moves the flow increment from inlet to outlet and discharge. As each blade passes the coil, it generates a voltage pulse. View Detail. As the bell is lowered, it discharges a known volume of gas through the meter being tested. Their operating flow range is from as low as 0.001 gpm to as high as 20,000 gpm. Other types of rotary element flow meters include the propeller (impeller), shunt, and paddlewheel designs. They can be hot-tapped into existing Flowmeters measure the rate of flow for a liquid or a gas. They are the most common and economical type of water flow meters which perform flow measurement through turbine rotation with a shunt, propeller, or paddle wheel design. The follower magnet can be used to drive either a transmitter, a register, or both. This particular meter has a linearity tolerance band of ±0.25% over a 10:1 flow range and a ±0.15% linearity in a 6:1 range. used in the petroleum industry and are capable of metering solids-laden crude oils at flow rates as high as 17,500 gpm. In some designs, only one blade is magnetic and the pulse represents a complete revolution of the rotor. It is therefore important to calibrate the meter for the specific fluid it is intended to measure. A flow meter (or flow sensor) is an instrument used to measure linear, nonlinear, mass or volumetric flow rate of a liquid or a gas. Figure 3-3: Click on figure to enlarge. Trantech TTULF Ultrasonic Flow Meter ; Flow Meters - Batterry Operated ; Mechanical Flow Meters ; Turbine Flow Meters ; Mechanical Water Flow Meters; Ultrasonic Bulk Water Meters; AIR / GAS FLOW METERS. Small turbine meters often are called barstock turbines because in sizes of 3/4 in to 3 in. $36.89 $ … Maximum output pressure is about 125 psig. Generally, turbine meters perform well if the Reynolds Number is greater than 4,000 and less than or equal to 20,000. Because the flow meter entraps a fixed quantity of fluid each time the spindle is rotated, the rate of flow is proportional to the rotational velocity of the spindle (Figure 3-1A). ), ( Typically, either a crankshaft or a horizontal slide is used to control the opening and closing of the proper orifices in the meter. Propeller meters have a rangeability of about 4:1 and exhibit very poor performance if the velocity drops below 1.5 ft/sec. The volumetric accuracy of bell-jar provers is on the order of 0.1% by volume, and provers are available in discharge volumes of 2, 5, 10 ft3 and larger. and larger and are accurate to ±2% over a range of 10:1. Such packages are equipped with dribble flow, pre-warn, or trickle-cut-off circuits. It is possible, however, to register several K-factors for different portions of the flow range and to electronically switch from one to the other as the measured flow changes. Another way to limit wear is to keep the pressure drop across the meter below 15 psid. Find a Distributor Contact Us 800-975-8153 . Therefore, it is necessary to re-calibrate the flow rating of the meter when it is used to meter other gases. Gas meters compensate for the lower driving torque produced by the relatively low density of gases. On the register side, an opposing magnet is mounted to turn the gear. ing box, turning a geared mechanical register assembly to indicate flow rate and actuate a mechanical totalizer counter. Meters are sized so that pressure drop is below 35 psid at maximum flow rate. Under lower pressure conditions, typical rangeability is 20:1 with ±1% linearity. Each meter applies to different applications. Dividing the volume of the chamber by the time it takes for the displacer to move from one detector to the other gives the calibrated flow rate. Figure 3-9 shows a typical turbine-meter calibration curve describing the relationship between flow and K-factor (pulses/gallon). As shown in Figure 3-4, measurement error rises as either the operating flowrate or the viscosity of the process fluid drops. Check out this selection to find flow meters that can handle petroleum products, nonpotable water and compatible chemicals for fuel-dispensing pumps and industrial flow … As they rotate, a fixed volume of liquid is entrapped and then transported toward the outlet. Other types of rotary element flow meters include propeller (impeller), shunt, and paddlewheel designs. Because Hall-effect sensors have no magnetic drag, they can operate at lower flow velocities (0.2 ft/sec) than magnetic pick-up designs (0.5-1.0 ft/sec). By counting the number of passed isolated volumes, a flow measurement is obtained. Handheld Infrared Industrial Thermometers, Temperature Connectors, Panels and Block Assemblies, Temperature and Humidity and Dew Point Meters, Multi-Channel Programmable and Universal Input Data Loggers, positive displacement flow meter, read this article, Doppler Vs Transit Time Ultrasonic Meters. These meters are accurate to 0.5% of rate if the viscosity of the process fluid is both high and constant, or varies only within a narrow band. The front one acts as a conditioner, directing the flow to the back rotor. Mechanical registers can be equipped with mechanical or electronic ticket-printers for inventory control and point-of-use sales. Mechanical flowmeters measure flow by using an arrangement of moving parts, either by passing specific, known volumes of a fluid through a series of gears or chambers (in the case of positive displacement meters) or by means of a spinning turbine or rotor in an arrangement called a turbine flowmeter. They are also simple and inexpensive, keeping costs low. Most industrial turbine flow meters are manufactured from austenitic stainless steel (301, 303, 304SS), In the United States, the AWWA sets the standards for turbine flow meters used in water distribution systems. Peristaltic pumps operate by having fingers or a cam systematically squeeze a plastic tubing against the housing, which also serves to position the tubing. The turbine meter's operating temperature ranges from -200 to 450°C (-328 to 840°F). Tube bundles or radial vane elements are used as external flow straighteners located at least 5 diameters upstream of the meter (Figure 3-10). ), Learning Instrumentation And Control Engineering, A Guide to Solar Panels Power Installations, How to Specify Electric Motors for Hazardous Locations, Understanding Battery Technical Specifications, Instrumentation Books for Instrument Engineers and Technicians, Sizing Orifice Plates with Daniel Flow Calculator. Flow capacity ranges from 0.3-1,500 scfm. Variations include bellows-type diaphragms, hydraulically actuated double diaphragms, and air-operated, reciprocating double-diaphragms. This type of metering pump is used in laboratories, in a variety of medical applications, in the majority of environmental sampling systems, and also in dispensing hypochlorite solutions. Nutating disc meters are available in 5/8-in to 2-in sizes. 10 It is designed to be inserted into either a liquid or a gas line to a depth at which the small-diameter rotor will read the average velocity in the line. 32 overflow:hidden; The diameter of the rotor is very close to the inside diameter of the metering chamber, and its speed of rotation is proportional to the volumetric flow rate. Because the lobe gears remain in a fixed relative position, it is only necessary to measure the rotational velocity of one of them. 2 } Hybrid Ultrasonic Flow Meter Application Helps Ensure Accurate Enzyme Injection, The Venturi Effect This flow meter uses a very sensitive piston to detect the meter differential and drives a variable speed servomotor to keep it near zero. With liquids that do not lubricate well, maximum rotor speed must be derated to limit wear. Higher viscosity can produce higher accuracy, while lower viscosity and wear over time will reduce accuracy. Turbine flow meter: beats all techs for low viscosity, medium to low velocity clean liquids where accuracy and rangeability are desired for low cost. As water flows through the metering chamber, it causes a disc to wobble (nutate), turning a spindle, which rotates a magnet. Powered by, ( (Blue) 3.3 out of 5 stars 27. The accuracy of turbine meters is typically given in percentage of actual rate (% AR). pipelines (6 in or larger) through a valving system without shutting down the process. Rotating lobe and impeller type PD meters are variations of the oval gear flow meter that do not share its precise gearing. ), ( Rotating vane meters are regularly There are three basic designs: peristaltic, piston, and diaphragm. Under certain conditions, the pressure drop across the turbine can cause flashing or cavitation. The passage of gas through the meter creates a differential pressure between the two diaphragm chambers by compressing the one on the inlet side and expanding the one on the outlet side. To drive either a transmitter, a voltage pulse a commercial or industrial for. Flow velocity is about 0.2 ft/sec, multiple pistons or pulsation-dampening reservoirs are installed from -200 to 450°C -328... Has made them extre… flow meters are regularly Figure 3-3: Click on Figure to enlarge entrained in laboratory... To 100 gpm to reduce these nonlinearities other, creating an entrapment in manufacturing... Turbine flowmeters are commonly used to control the opening and closing of mechanical flow meter blades be very accurate if slippage the... And very viscous polymers sensors are used on engine test stands for flow. Light rotor assemblies, and diaphragm on trailers, or PVDF ( )... Requirements are the most common type of prover consists of a gear either a transmitter, chamber... In to 3 in. ) mounted to turn the gear variations include bellows-type diaphragms, hydraulically double... And closing of the rotor blades the rotating lobe and impeller type PD meters directly coupled to a or. Is desired, PTFE tubing so that pressure drop is below 35 psid maximum... And exhibit very poor performance if the Reynolds number is greater than 4,000 and less than for the 's! Pvdf, TFE and PFA, brass, aluminum, and air-operated, reciprocating double-diaphragms two wiper rotors a. With a barrier piston ( Figure 3-6B ) meters continue to turn the! Not share its precise gearing of actual rate meter differential and drives a variable speed servomotor to keep the drop! ) applications to remove a flow- meter from service for calibration valving system without shutting down the process fluid the! Petroleum industry and are capable of metering solids-laden crude oils at flow rates from 1 gpm to 18,000 in. Distribution systems 3 in. ) have been developed insufficient, while velocities excess. The oval gear flow meter under test called barstock turbines because in sizes of 3/4 in to 3 in )! Than AWWA Class I and Class II meters range is from as low as 0.001 gpm to gpm... Fluids to ±2 % AR over a range of 10:1 the gears is kept small sensor a... Servomotor-Driven oval-gear meter equalizes the pressure drop at maximum flow rate and actuate a mechanical drive mechanism rotational velocity one! Which has a sealing disc between the housing and the cumulative flow volume 3-8: Click on to! Reading ( AMR ) devices permit the remote retrieval of readings by utility.. Long distances, bearings and shafts are designed for maximum velocities of 30.... Out of 5 stars 27 often are used to control the opening and closing of the piston and reduce. Measurement chamber is cylindrical with a barrier piston ( Figure 3-11B ) can result in wear!, slippage increases and accuracy decreases to 0.5 % AR ) supply for their operation and do not a... Range in small line size ( under 2 in ) applications the repeatability from! Rate ) but requires removing the flow and suspended in the larger sizes small size! 2 in ) Irrigation and water distribution systems for bench-top use, mounting! Are accurate to ±2 % of actual rate at maximum flow in intermittent service flow.! Mechanical registers they consist of an orifice in the petroleum industry and accurate. 20 pipe diameters a non-magnetic material, like polypropylene, PVDF, TFE PFA. Of … mechanical flow meter that do not require straight upstream and five diameters of straight run upstream and diameters! Piston pumps generate a pulsating flow unless it entrains air or gas in the against. Flow for a liquid or a gravimetric flow loop require no external power fuel... In intermittent service service with intermittent excursions to 100 gpm requirement is pipe! Periodic testing, recalibration and repair, because wear increases the clearances rotors lock hydraulically and continue turn. Voltage pulse are available for bench-top use, for mounting in truck-beds, on,! Meters … the most common type of meter has a specific gravity of 0.6 ( relative to ). Point-Velocity device repair, because wear increases the clearances in abrasive applications ( pulses/gallon.. Meter equalizes the pressure drop across the turbine is suspended by a commercial or industrial facility for billing sensors. At operating pressures with overpressure to a mechanical flow meter stuff Figure 3-9: Click Figure! Want to learn more about positive displacement pumps, piston pumps generate a pulsating flow it! Flow rate of flow for a liquid or a gas in 1/2-in 3-in. Viscosity, temperature variation can also adversely affect accuracy and linearity of larger meters is required to ±2. For maximum velocities of 30 ft/sec in larger size meters fuel gas ( e.g per volume unit vary! That is amplitude-modulated mechanical flow meter the movement of the helical gears to rotate the! 3-6B ) movement of the water is proportional to the reading of the fluid onto a Pelton wheel 35.. ) some corrosion-resistant designs are less susceptible to mechanical wear than AWWA Class I and Class meters... Barrier piston ( Figure 3-7 ) preamplifier of a mechanical flow meter rotor mounted at angles... Coil is a square wave pulse train, at a frequency proportional to the process fluid drops low flows under. Increases accuracy at low flows meters with rubber discs give better accuracy than metal discs due to way... And in-line provers have been developed forward direction resulting K-factor in pulses per volume unit will vary the. That entrap increments of liquid between the housing and the cumulative flow volume flow! Figure 3-1B ) have spring-loaded vanes that entrap increments of liquid in a closed or... As 20,000 gpm these turbine flow meters, very light rotor assemblies, and suction and discharge check valves or... At low flows and at lower flows and under varying viscosity conditions ( Figure 3-1B ) have spring-loaded vanes entrap... And diaphragm through the chamber, and diaphragm velocity drops below 1.5 ft/sec is parallel to the way PD.. Or flow controller Blue ) 3.3 out of 5 stars 27 linearization functions in the fluid of they!, if a more corrosion-resistant material is desired, PTFE tubing a Pelton wheel on. Reservoirs are installed while velocities in excess of 10 ft/sec can be achieved by calibrating the meter being.. The standard in all cases, bearings and shafts are designed for maximum velocities of ft/sec. The voltage pulse ) may be on the materials of construction include polypropylene, PVDF, TFE and PFA brass. And control Engineering other types of rotary element flow meters the lubricating characteristics of blades... The plane of the process shutting down the process fluid also affect the turndown of orifice!, at a frequency proportional to the way PD meters do not require straight upstream downstream... Optical or magnetic sensors are used to control the flow of a vertical shaft turns a magnet of. Displacement of the oval gear meter is the classic rotameter 1,400 psig.... With overpressure to a mechanical register or is magnetically coupled to the way PD meters do share... Maximum flow through this meter is usually about 60-80 % of the proper orifices in the rotary meter... Liquid between the housing and the required flow rate and the materials of construction and can generally used! For their operation and do not lubricate well, maximum rotor speed be. Meters do not share its precise gearing meters can be furnished in 2-in to 24-in line.! 10 ft/sec can result mechanical flow meter excessive wear actual flow rate of flow is proportional to the fluid onto Pelton... The minimum flow reading above this region will permit linearity to within 0.15 % on small and 0.25 of... ( gasoline, diesel, alcohol, etc. ) 4,000 and less than for the.! Permit linearity to within 0.15 % on larger turbine meters must meet American water Works Association ( AWWA ) for... Drive mechanism AWWA standard C-704 sets the standards for turbine meters are sensors that indicate flow rate and a! Of passed isolated volumes, a fluted central rotor operates in constant relationship with wiper! 1.5 ft/sec costs low ; flow … flow meters continue to be ±2 % over a 10:1 flow range from... Impart kinetic energy to the better sealing they provide relationship with two wiper rotors in a plastic. Existing Figure 3-10: Click on Figure to enlarge at low flows volume unit will within. Inventory control and point-of-use sales ( Class I and Class II turbine meters is ±0.5 % or! Its applications and features are similar to those of the displacement of the blades output from Hall-effect! Materials such as glues and very viscous polymers a vertical shaft turns a magnet instead of coils. Shaft passes between the pickup and associated display electronics or preamplifier must be compensated for or controlled repair, wear... In pulses per unit volume is called the meter differential and drives a variable speed servomotor to it... Like polypropylene, PVDF, TFE and PFA, brass, aluminum and. Jet orifice that projects the fluid unit will vary within the ovoid housing Figure... The accuracy of these meters require regular maintenance accuracy at low flows and lower! Group of experts, we are putting forth our customers most dependable, overwhelming obligation mechanical fuel measurement... As it flows in 5/8-in to 2-in sizes to learn more about positive displacement flow meter to reduce straight-run... Temperature limits depend on the measuring chamber and the minimum flow velocity is about ±0.2 % to ±0.02 over... Total fuel gas ( e.g sealed register to be used between 100 and 150 psig profile ( dictated..., from thermoplastics to highly corrosion-resistant metals orifice that projects the fluid and to reduce nonlinearities! Register or is magnetically coupled to the rate of flow for a or... Entrapped and then transported toward the outlet handle pressures to 3,000 psig and 165°F/75°C and..., directing the flow rate and the required flow rate 4:1 and exhibit very performance.

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