Mass Flow Meter and Magnetic Flow Meter are our commonly used flow meters. What Is the Difference Between Mass Flow Meter and Magnetic Flow Meter?There are several options for measuring the flow of liquids. The two most common types of flow meters are mass flow meters and magnetic flow meters. Each has its own set of advantages and disadvantages. In this article, we will explore the differences between mass flow meters and magnetic flow meters, including how they work, what their benefits are, and what their potential disadvantages are.What is a Mass Flow Meter?A mass flow meter, also known as a mass flow sensor, mass flow meter working principle is measures the flow rate of a fluid based on its mass. The flow rate is determined by the difference between the mass of the fluid entering the meter and the mass of the fluid leaving it. This difference is then taken into account.Due to their direct mass flow measurement, high accuracy, and ability to measure fluids with varying properties, coriolis flow meters are commonly used in this industry. Flow meters with magnetic components can also be used to measure corrosion-resistant fluids, but they are restricted to conductive fluids, and petrochemical products are not conductive.The most accurate flow meters are Coriolis mass flow meters. However, these are not appropriate for many applications because they are extremely expensive, usually large, and are complete overkill for most applications.There are several different types of mass flow meters, including Coriolis mass flow meters, thermal mass flow meters. Each type works in a slightly different way, but they all rely on the principle of measuring the mass of the fluid to determine the flow rate.The accuracy of mass flow meters is one of their key advantages. In contrast to other types of flow meters, they are less affected by changes in temperature and pressure, which can cause errors. This makes them suitable for a variety of applications where accuracy is critical, such as the chemical and pharmaceutical industries.What is a Magnetic Flow Meter?A magnetic flow meter, also known as a magmeter, measures the flow rate of a conductive fluid using magnetic fields. The method works by sending a current through a pair of electrodes, creating a magnetic field. A conductive fluid flows through a pipe, disrupting the magnetic field, and this disturbance is used to determine how fast the fluid flows.Magnetic flow meters are commonly used to measure the flow of water and other conductive liquids, such as sewage, slurry, acids and bases. They are also often used in the food and beverage industry, as well as in the pulp and paper industry.Among the key advantages of magnetic flow meters is their non-invasive design. Because they use magnetic fields to measure the flow of the fluid, they do not require moving parts or obstructions in the pipe, making them easy to install and maintain. Additionally, they are relatively resistant to temperature and pressure changes, making them ideal for harsh environments.Differences Between coriolis vs magnetic flow meterWhile both mass flow meters and magnetic flow meters are used to measure the flow of fluids, there are several key differences between the mass flow meter vs magnetic flow meter:Accuracy: Both mass flow meters and magnetic flow meters are known for their accuracy. But mass flow meters are generally considered to be more accurate, especially in applications where the temperature or pressure may vary.Compatibility: Mass flow meters are compatible with a wide range of fluids, including gases, liquids, and slurries. Magnetic flow meters, on the other hand, are only suitable for conductive fluids.Measurement Principle: As mentioned above, mass flow meters measure the mass of the fluid in order to determine the flow rate. While magnetic flow meters use magnetic fields to measure the flow of conductive fluids.Maintenance: A mass flow meter may require more frequent maintenance, such as cleaning and calibration, than a magnetic flow meter. A magnetic flow meter, on the other hand, requires relatively little maintenance, because it has no moving parts and is not affected by wear and tear.Cost: In terms of cost, electromagnetic flow meters are more affordable than mass flow meters. The cost of electromagnetic flow meters is moderate. It is suitable for more users. Mass flow meters have higher measurement accuracy, but they are also more expensive. For customers with specific needs.
The vortex flow meter accuracy has always been one of the topics we are more concerned about. The measurement accuracy determines whether the flowmeter can obtain the mass flow of the medium more accurately during work. First of all, let's classify the vortex flowmeter according to the following principles; the vortex flowmeter can be divided into flange type and clamping type according to the connection mode of the sensor, and can be divided into heat-sensitive type, stress type, capacitive type, and ultrasonic type according to the detection method , Vibration type, photoelectric type and fiber optic type, etc. According to the purpose, it can be divided into ordinary type, explosion-proof type, high temperature type, corrosion resistance, low temperature type, plug-in type, etc. According to the composition of sensors and converters, it is divided into two types: integrated type and split type, and according to the measurement principle, it is divided into volume flowmeter and mass flowmeter.Speaking of which, the accuracy and vortex flowmeters maintenance efficiency is basically ±0.5%R~±2%R for measuring liquids, ±1%R~±2%R for gases, and the repeatability is generally 0.2%~0.5%. Since the instrument coefficient of the vortex flowmeter is relatively low and the frequency resolution is low, the instrument diameter should not be too large, usually below DN300.Main factors affect the vortex flow meter maintenance efficiency and accuracy1. Vibration of pipeline and flowmeterAs pipeline vibration acceleration increases, so too does the error of the instrument coefficient of the vortex flowmeter. The overall shock resistance to this is relatively low. But as the flow rate rises, despite any changes in vibration frequency, this error tends to decrease. The instrument coefficient of the vortex flowmeter will also be reduced if there is an increase in pipeline vibration frequency. Poor reinforcement of the pipe and flowmeter or placing them close to a motor can result in vibrational interference with a vortex flowmeter's measurements, leading to values that are too high or even causing miscalculations of flow.2. Changes in pressureThe heating network pipeline includes multiple valves and pressure-reducing valves, which all have the ability to alter the line's pressure. The vortex flowmeter is not an accurate indicator of mass flow, because its measurement largely depends on two factors: the flow rate of the pipeline and the density of steam. This density is determined by pressure; thus, when a valve is opened, it can lead to an alteration in pressure that subsequently changes the steam’s density and produces a potentially inaccurate reading. Consequently, such occurrences can cause measurement inaccuracies.3. Dryness changeIn order to measure saturated steam with a vortex flowmeter, the saturated steam must have a dryness of not less than 85%, but the actual situation on site is that the saturated steam's dryness is less than 100% in the boiler, and the saturated steam's dryness will be less than 85% of the time, resulting in a drop in measurement vortex flow meter accuracy.4. The outlet side of the flowmeter leads to the atmosphereSince the vortex flowmeter has an open outlet to the atmosphere, excessive front and rear errors will cause the flow rate to exceed its upper limit, so the change in flow rate cannot be accurately reflected. Zero point drift and unreasonable pressure induction pipe arrangement are mainly responsible for this situation.5. The installation of straight pipe sections before and after the flowmeter does not meet the requirementsIf certain requirements are not met during the installation of the vortex flowmeter, the correct formation of the Karman vortex street principle will be affected, resulting in an inaccurate measurement of saturated steam.As can be seen here, the accuracy of the vortex flowmeter determines the accuracy of the measurement medium. Consequently, you should read the instrument manual thoroughly after purchasing the vortex flowmeter before installing it to prevent unnecessary unknown factors from affecting the measurement accuracy after installation.Beijing Sincerity, a professional vortex flow meter supplier & manufactuer, has developed over years to manufacture the Coriolis Mass Flow Meters industries. Through continuous research, development and transformation, we have become the leader of the Coriolis Mass Flow Meters industries in China.Beijing Sincerity has powerful technology knowledge over the flow meter industries. The Coriolis Mass Flow Meter are suitable for different kinds of industries--- high requirements testing experiments of universities, research institutes; and also the petroleum, medicine, metallurgy, electricities industries.
Some of the advantages of turbine flow meters include:Useable for a wide range of applications.Suitable for gases and liquids.There is a possibility of achieving an accuracy of 0.25% with turbine flow meters, which are highly accurate and precise.Economical to purchase so it is one of the preferred flow meters in world trade settlement.Easy to set up and operate, compact structure, and lightweight.Useable for a wide range of applications, medium, and large diameters are generally up to 20:1 or more, and small diameters are 10:1, and the starting flow rate is also low.Less pressure loss. They produce an only moderate head loss.(1) High accuracyHighly accurate and precise, insertion turbine flow meter are ±0.5% accurate normally. However, it is possible to achieve an accuracy of ±0.25%.For liquids, it is generally ±0.25%~±0.5%, for gas turbine flow meter, it is generally ±1.5%, and the special special type is ±0.5%~1%. Turbine flowmeters are the relative high accurate flow meters comparing to other types flow meters.(2) Good repeatabilityShort-term repeatability is up to 0.05% to 0.2%. It can be used for custody transfer if users frequent calibrate the flow meters.(3) Wide measuring rangeFor large size turbine sensor, the turn down ratio can be 40:1~10:1, and for small size sensor tube, it can be 6:1 or 5:1.(4) Output pulse frequency signalThere is no zero drift, and the signal resolution is very high due to the very high frequency signal (3x4Hz) obtained from the turbine sensor.(5) Suitable for high pressure measurementThe meter body is easy to make a high-pressure type meter.(6) There are many types of structures, which can adapt to the needs of various measurement purpose, such as can be made into thread or flange type , or even made into tri-clamp type for hygienic purpose.No zero drift, strong anti-interference ability.When they are calibrated at fairly frequent intervals, turbine meters over about 50mm, and especially very large sizes, have excellent short-term repeatability.In the best meters of this type, the output is directly digital and practically linear over a wide range of flow rate-about 5 or 6:1 in the smaller sizes, increasing to about 10:1 in large turbine meters.They are compact, being only the same diameter as the pipe in which they are installed.The compactness of the smaller sizes of turbine flow meters, combined with their freedom from any components necessitating a hole in the pipe wall, enables them to be designed for operation at very high pressures.If they should seize up, they do not block the flow.Some disadvantages include:Requirement of clean, dry liquid/gas samplesErrors caused by high viscosity in samplesFrequent calibration checks neededGas flowmeters are easily affected by density and are closely related to temperature and pressure, so temperature and pressure corrections are required.Regularly add oil to ensure adequate lubrication of the bearing to ensure measurement accuracy and prolong the service life.They are rather more expensive than many types of flowmeters, particularly in larger diameters.Since the turbine meter's original calibration is bound to change with wear or fouling surfaces over time, it is necessary to periodically recalibrate if high accuracy is to be maintained. Liquids with poor lubricating quality are more likely to cause bearing problems, and their effect can be severe if they contain a high proportion of suspended solids or are highly corrosive.The calibration of a turbine meter is affected by variations in viscosity of the liquid being measured. That effect is more pronounced in smaller meters, which need a calibration device such as a pipe prover to ensure accuracy when only slight changes in temperature are likely to alter the viscosity. This approach is commonplace in the petroleum industry. Turbine meters are also susceptible to flow disturbances and particularly swirls, with smaller sizes offering reduced performance due to increased friction from bearings.Above are turbine flow meter advantages and disadvantages, want to konw more about turbine flow meter, contact Sincerity Group.
Mass flow measurement is the basis of many key elements throughout industry, including most recipe formulations, material balance determinations, and billing and custody transfer operations. With these being the most critical flow measurements in a processing plant, the reliability and accuracy of mass flow detection is very important. A (Brief) History of Mass Flow Measurement In the past, mass flow was often calculated from the outputs of a volumetric flow meter and a densitometer. Density changes were either directly measured or were calculated using the outputs of process temperature and pressure transmitters. Ultimately, because the relationship between process pressure or temperature and density are not always precisely known, these were not very accurate measurements. One of the early designs of self-contained mass flow meters operated using angular momentum – it had a motor-driven impeller that imparted angular momentum (rotary motion) by accelerating the fluid to a constant angular velocity. The higher the density, the more angular momentum was required to obtain this angular velocity. Downstream of the driven impeller, a spring-held stationary turbine was exposed to this angular momentum. The resulting torque (spring torsion) was an indication of mass flow. However, with complex mechanical designs and high maintenance costs, these types of meters have been largely replaced by more robust and less maintenance-demanding designs. One such design is the Coriolis mass flow meter, which is widely considered the most accurate type of mass flow meter and is widely used in industrial applications for accurate measurement. Coriolis flow meters feature instrumentation that function on the working principle of mass flow meter effect – a notable (and strange) phenomenon whereby a mass moving in a rotating system experiences a force acting perpendicular to the direction of motion and to the axis of rotation. The first industrial Coriolis patents date back to the 1950s and the first Coriolis mass flow meters were built in the 1970s. The coriolis flow meter working principle It was G.G. Coriolis, a French engineer, who first noted that all bodies moving on the surface of the Earth tend to drift sideways because of the eastward rotation of the planet. In the Northern Hemisphere, the deflection is to the right of the motion; in the Southern Hemisphere, the deflection is to the left. This drift plays a principal role in both the tidal activity of the oceans and the weather of the planet. Because a point on the equator traces out a larger circle per day than a point nearer the poles, a body traveling towards either pole will bear eastward because it retains its higher (eastward) rotational speed as it passes over the more slowly rotating surface of the Earth. This drift is defined as the Coriolis force. When a fluid is flowing in a pipe and it is subjected to Coriolis acceleration through the mechanical introduction of apparent rotation into the pipe, the amount of deflecting force generated by the Coriolis inertial effect will be a function of the mass flow rate of the fluid. If a pipe is rotated around a point while liquid is flowing through it (toward or away from the center of rotation), that fluid will generate an inertial force (acting on the pipe) that will be at right angles to the direction of the flow. With reference to Figure 1, a particle (dm) travels at a velocity (V) inside a tube (T). The tube is rotating about a fixed point (P), and the particle is at a distance of one radius (R) from the fixed point. The particle moves with angular velocity (w) under two components of acceleration, a centripetal acceleration directed toward P and a Coriolis acceleration acting at right angle to ar: ar (centripetal) = w2r at (Coriolis) = 2wv In order to impart the Coriolis meter acceleration (at) to the fluid particle, a force of at (dm) has to be generated by the tube. The fluid particle reacts to this force with an equal and opposite Coriolis force: Fc = at(dm) = 2wv(dm) Then, if the process fluid has density (D) and is flowing at constant speed inside a rotating tube of cross-sectional area A, a segment of the tube of length X will experience a Coriolis force of magnitude: Fc = 2wvDAx Because the mass flowrate is dm = DvA, the Coriolis force Fc = 2w(dm)x and, finally: Mass Flow = Fc / (2wx) This is how measurement of the Coriolis force exerted by the flowing fluid on the rotating tube can provide an indication of mass flowrate. While rotating a tube is not necessarily practical standard operating procedure when building a commercial flow meter, oscillating or vibrating the tube – which is practical – can achieve the same effect.