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Grounding Ring vs Grounding Electrode, which one to use?

For any magnetic flowmeter system to function properly it must have three connections (including a ground) to the process liquid passed from the magnetic flow tube onto the magnetic flow transmitter. About 80 percent of the time, problems with the flow measurement readings provided by a magnetic flowmeter can be traced directly to improper solution ground connections. 

Figure 1. Flanged-style magmeter flowtube installed in metal process pipe.

Two of the three connections are passed from the magnetic flow tube’s measuring electrodes, which sense the energy created within the magnetic flow tube based on Faraday’s Law, onto the magnetic flow transmitter via the two electrode signal cable leads. This energy is then represented by the magnetic flow transmitter as a measurement of flow rate. The required third connection to the process is often referred to as the solution ground, or simply SG. This SG connection is a critical connection from the process liquid passed over to the body/case of the flow tube and then onto the magnetic flow transmitter via the solution ground lead portion of the electrode signal cable. 

The SG connection is actually the reference point of the measurement, and it is required for a magnetic to consistently achieve a stable zero flow measurement reading, as well as to provide accurate measurements during flow. Without this reference SG connection, there can be no confidence in the flow rate measurement.

Two main causes are responsible for the majority of solution ground connection problems. First, the SG connection from the process to the magnetic flow tube’s body/case is missing. Secondly, the SG connection fails to pass properly from the magnetic flow tube’s body/case onto the magnetic flow transmitter’s SG terminal.

Magmeter Grounding Rings vs. Grounding Electrodes

In order to determine when to use grounding rings or grounding electrodes, the first thing that must be understood is their primary function, and if they are even required. The primary function of grounding rings or grounding electrodes is to provide the required SG connection when unlined metal process pipe is not available. Grounding rings are metal rings that make contact with the process liquid.

These rings are installed between the process pipe and the magnetic flow tube. These metal rings must then be attached to the flow tubes body/case or flange in order to pass on this SG connection—usually by some wiring or bolting method, depending on the style of grounding ring used. Examples with detailed illustrations are shown in this article. In addition to providing the required Solution Ground, a grounding ring on the upstream side of the magnetic flow tube also provides a fair degree of liner protection to the leading edge of the flow tubes liner when used in moderately abrasive applications.

Figure 2. Typical wafer-style magmeter flowtube with supplied SG wires installed in flanged metal process pipe.

Figure 3. Flanged-style magmeter flowtube with SG grounding straps and rings installed in nonmetallic pipe.

Magnetic grounding electrodes are simply one or more additional electrodes, other than the flow tube’s measuring electrodes, that contact the process liquid while also making contact with a metallic portion of the flow tube’s body/case. When using a flow tube with grounding electrodes, no additional wiring is required to pass the SG connection onto the flow tubes body/case—it is done internally. When using flow tubes that already contain grounding electrodes, grounding rings are not normally required. 

Contact the supplier to determine which flow tube models are available with grounding rings and/or grounding electrodes. 

Figure 4. Magmeter liner protection (grounding) rings used for both liner protection and process fluid grounding with PTFE.

For many of the more hazardous process liquid applications, magnetic flowmeter systems are often the preferred technology simply because they are available with numerous liner and exotic electrode material choices, thus providing compatibility with many hazardous chemicals. If grounding rings or grounding electrodes are required, they should be made from the same material as the measuring electrode based on chemical compatibility with the process liquid.

In hazardous process liquid applications, the adjacent process piping is usually nonmetallic or lined. Because grounding rings made from exotic materials are rather expensive, grounding electrodes can offer substantial cost savings over grounding rings and provide easier installation with fewer leak-points.

Figure 5. Magmeter liner protection (grounding) rings with Neoprene, EPDM, Linatex, or Ebonite.

Does the Magmeter Need 1 or 2 Grounding Rings?

For decades, two grounding rings were always the recommendation when required for magnetic flow meters. When using older style legacy magnetic flow transmitters, this is still true. However, with current intelligent microprocessor-based magnetic flow transmitters, two grounding rings are no longer necessary, as the same level of zero stability and accuracy can be provided with just one grounding ring. This not only reduces the overall cost of materials but also makes installation easier. 

When using one grounding ring, it should be placed on the upstream side of the magnetic flow tube. In addition to providing the required solution ground, placing this grounding ring on the upstream side of the flow tube also provides a fair degree of liner protection to the leading edge of the flow tube’s liner when used in moderately abrasive applications.

How Magmeter Flowtube Installation Affects the Solution Ground

Proper flow tube installation is critical for correct SG in magnetic flow meters. In the case of metal process piping, a properly installed flow tube means that no additional solution grounding rings or electrodes are required. For nonmetallic pipe or liner configurations, a solution ground method is required, and careful attention must be paid to grounding ring or electrode connections and placement. The following provides some tips for proper SG connections to the magnetic flow transmitter.

SG Connection with Metal Process Pipe
Flanged-style flow tubes: The most common method of passing the SG connection from the process itself onto the magnetic flow tube’s body/case is through flanged, unlined, metal process pipe bolted to a flanged magnetic flow tube (Figure 1). 

When the metal flanges on each side of the magnetic flow tube are bolted to the magnetic flow tube’s metal flanges, the SG connection is made. It passes onto the magnetic flow tube’s body/case, and eventually to the magnetic flow transmitter. In this metal-to-metal installation scenario, neither grounding rings nor grounding electrodes are required.

Wafer-style flow tubes: Wafer style flow tubes have no flanges of their own. Therefore, when a wafer-style magnetic flow tube is mounted between flanged, unlined, metal process piping, the proper method of passing the SG onto the flow tube is by attaching supplied SG wires that ship with the flow tube. Be sure to connect these wires to the metal process pipe flanges on each side of the wafer flow tube (Figure 2).

In this installation scenario, grounding rings are not required. Note that grounding electrodes are not available on wafer-style magnetic flow tubes; the supplied wires are to be used.

SG Connections with Nonmetallic/ Plastic/PVC/Lined Process Pipe
Flanged-style flow tubes: When flanged-style flow tubes are mounted between nonmetallic, plastic, PVC or lined process piping, the SG must be passed to the flow tubes body/case through some path other than the process piping flange bolts. In such installation scenarios, either grounding rings or grounding electrodes are required (Figure 3). 

Figure 6. Magmeter wafer-style flowtube installed in non-metallic pipe (bolts not shown).

For grounding-ring applications, if traditional orifice plate-style, or Type C, grounding rings are used, the grounding rings must be attached to the flow tube’s body/case using grounding straps. These straps are attached to the flow tube’s flanges, or to grounding wires attached to a lug located on its remote junction box or top-mounted transmitter interface plate. Type E grounding rings utilize customer-supplied bolts, rather than grounding wires or grounding straps. 

For process pipe that is lined with a nonmetallic material, the ring configuration is slightly different. Figure 4 shows the application of Type E and Type C grounding rings inlined process pipe configurations.

Wafer-style flow tubes: When wafer-style flow tubes are mounted between nonmetallic, plastic, PVC or lined process piping, grounding rings are required. The SG must be passed on to the flow tube’s body/case by connecting the attached, supplied SG connection wires to the grounding rings (Figure 6.) 

As with flanged flow tubes, if traditional orifice plate-style, or Type C, grounding rings are used, the grounding rings must be attached to the wafer-style flow tube’s body/case using grounding straps or wires. The grounding wires are attached to a lug located on its remote junction box or top-mounted transmitter interface plate. Type E grounding rings utilize customer-supplied bolts rather than grounding wires or grounding straps.

It is important to remember the purpose of the solution ground connection is to serve as a reference point of the flow measurement. This lets the magnetic flowmeter read a stable zero flow and achieve accurate measurement in flow conditions. The placement and type of SG and connection devices are critical in meeting this goal. The method used varies with the range of flowmeter body types, process pipe construction, and liner materials. When all of these factors are considered, and the proper SG configuration is employed, results will meet performance and consistency expectations. Without a properly installed solution grounding method, confidence in the flow rate measurement will be diminished. 

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Low emission glass manufacturing (Low-E) with Improved repeatability & plug-and-play functionality

Low-E glass incorporates multiple layers of metal or other compounds as a surface coating that provides high transmittance for visible lights and high reflectance for mid-IR and far-IR lights.

The coating benefits are excellent heat insulation and favorable light transmission compared to standard and traditional-coated glass used in the building industry.


In Low-E glass manufacturing, vacuum magnetron sputtering is a common coating technique used across the globe. In this process, gas flow (inert gas Ar or reactive gas O2 and N2) in the vacuum environment must be controlled with a top-quality mass flow controller (MFC) to maintain a stable vacuum level.

With the magnetron target acting as the cathode, a high voltage provided by an AC or DC power supply will ionize process gas to generate plasma. Electrons move at high speed under the joint force of the electricfield and magnetic field, colliding with gas molecules and creating more positive ions and electrons.

After gaining a certain energy, positive ions in the electric field will hit the cathode target material. The sputtered target material deposits on the glass substrate to form thin films. Uniform and consistent film layers are required.



Inflow gas should be maintained at a very stable level in the coating process to avoid uneven coating and significant spots and negatively impacting the general energy of particles in the coating, which is not favorable for reactive deposition. A complicated gas distribution system requires numerous of process gas branches. Installation and commissioning of single channel gas circuits are tedious with heavy work load. In addition, this system typically reduces efficiency, and generates multiple leakage points. Human operation errors (wrong connection of gas mixing and connection circuits) also can negatively impact operations.


MEMS technique of the MFCs provides for a 350ms rapid response. Plug-and-play functionality and no warm-up periods improve user productivity.

Vögtlin Mass Flow Controllers have a unique way of compensating for changes in ambient and gas temperature, which strongly improves the repeatability. The MEMS technology insures a long-term stability without any drift as long as the gas supply is clean and dry.

Only one bolt is required to fix an MFC, allowing faster and more accurate removal/assembly.

An Integrated valve bank design and accurate internal mixing and distribution pipe design help avoid operational risks and improve end user comfort. Other benefits include saving of consumables for gas source pipes, reduced leakages points and field installation time as well as an easy and accurate realization of complicated gas mixing and distribution process.

Units can be calibrated for multiple gases and parameters, which leads to significant reductions in spare part inventories and cost savings.

Key Features

  • High repeatability & reliability
  • Short response time
  • Safe and fast control
  • Compact unit with high-quality components


  • Analog
  • Modbus RTU
  • Profibus DP-V0/DP-V1
  • Profinet
  • EtherCAT

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Measurement and Control of Low Gas Flow Rates

Mass Flow Meter and Controller Overview


There are several fundamental measurement techniques for flow meters, such as:

]Other than the ones mentioned above, there are some less known unique types of flow meter technologies that often offer solutions for individual applications. There is not one “Best Flow Meter”, everything depends on the application and what the user expects from the unit.

In this article, we look at measuring instruments for relatively low gas flows, from a few cc/min to 500 or 1000 ln/min for example. In this application area is the gas mass flow meter with the thermal bypass concept the most common instrument. There are gas mass flow meters (MFM) and mass flow controllers (MFC). The latter is a flow meter equipped with a control valve, and the user can provide a setpoint that determines a generated gas flow. MFCs is the reference to these instruments.

Measurement Concept

Red-y Smart Schematic

In the thermal bypass concept, most of the measured gas flow through a bypass. In the bypass is an element that generates a minimal pressure drop. As a result, a small quantity of the gas runs through the sensor, which runs parallel to the bypass. This sensor measures the gas flow, which is representative of the total amount of gas monitored. Each instrument is built for specific gas and a particular range of measurement.

Mass flow meters (MFM) and mass flow controllers (MFC), the names speak for themselves: these instruments measure and regulate the gas mass flow, for instance in kg/hr. The measured value can also be expressed in units of normalized volumes, such as ln/min (normal liter per minute) or SCFH (Standard Cubic Foot per Hour). In SCFH (Standard Cubic Foor per Hour)here the “S” refers to 20°C and 1 atmosphere, while NCCM (Normal Cubic centimeters per minute) with reference conditions as 0°C and 1 atmosphere. After all, there is a fixed relationship of a gas in mass units versus normalized volumes (density).

There is a distinction between the MFCs based on a capillary sensor and instruments with a MEMS (Micro-Electro-Mechanical System) sensor. Both sensor techniques have advantages and limitations. The word “cons” is here deliberately avoided because there are no bad measuring instruments. The application should drive preference example like Porsche 911 is a fantastic car, but you shouldn’t use it in the sand of the Sahara.

What is Capillary Flow Sensor?

The capillary sensor consists of a thin steel tube (0.2 to 1 mm o.d.) around which wrap with two thin platinum wires. The platinum wires act as electrical resistance and are part of a Wheatstone bridge. The resistance value of the platinum wire depends on the temperature. There is a current going through these wires, which heats them up. At zero flow is the resistance is the same, but when the flow goes through the sensor, there will be a difference in temperature that will be detected by the electronics.

Laminar Flow Element (LFE) equip in MFC with a capillary sensor in the bypass. This LFE creates laminar flow behavior, just like inside the sensor. The LFE means that the relationship between the flow through the sensor versus the flow through the bypass is almost linear over the measured range. Due to this linearity, it is possible to calibrate this MFCs with a cheap, pure gas like air and use a known factor to make the meter suitable for another exotic, explosive, poisonous or inflammable gas. If this so-called K-factor is applied, there will be additional uncertainties.  In user manuals of renowned manufacturers are further indicative inaccuracies reported to more than 2%. Parameters such as viscosity, pressure, and temperature affect the accuracy of the K-factor. It is essential to take note of this traditional calibration method, which creates uncertainties which are not often mentioned in the documentation.

This type of MFM/MFC must be calibrated with the actual gas as used in the application. The advantage is that the instrument thereby is more accurate. For some exotic gases, a correlation is possible, although the repeatability stays very low, the accuracy will suffer.

Figure 3: Generic overview capillary mass flow meter

Another ability of the capillary sensor is the possibility by some manufacturers to make all wetted part from one material, for instance, stainless steel or Monel so that the units are resistant to extreme corrosive gases.

What is MEMS Flow Sensor

The MEMS-based MFM/MFC has no LFE but a regular by-pass. The function is to ensure a defined percentage of the total gas flows through the sensor. The bore of the sensor is much larger so that for example the pressure drop is relatively low and the sensor less sensitive to pollution than a capillary. A MEMS sensor is also a lot more sensitive and due to that a turndown of 1000:1 is obtainable (versus 50:1 for capillary sensors).

The biggest advantage of the MEMS sensor is, however, that there is no (measurable) drift. Drift is a slow shift of the zero and the measured value at a given flow hence affects the accuracy.

MEMS Sensor Measurement Principle
Figure 4: Sensor of MEMS mass flow meter

The Pros and Cons

Capillary sensors exhibit effects of mechanical and thermal stress on the Platinum wires and aging of insulation materials. The capillary sensors must receive a “burn-in” in heated cabinets to speed up the aging process. Aged Capillary sensors exhibit less drift than, but it is still there. The effect is sometimes hidden by the manufacturer with low-flow cut-off options. The test signal is forced to zero under a specific value so hide the small drifts.

The MEMS sensors consist of two or three temperature sensors and a heater, vapor deposited as a microscopic molecular layer on a thin membrane. Conceptually the MEMS is sensor low-energetic and due to the membrane thermally and stress isolated, this ensures that MEMS sensors are free of any mechanical and thermal stress. An additional plus point: the sensor is part of an electronic circuit all mounted on the MEMS. The measured signal is immediately digitized on the MEMS sensor itself. No bad connections, no EMC distorting the signal. These are the main reasons why MEMS sensors are without drift and maintain a long-term accuracy, reproducibility, and reliability.

Other advantages are that the sensor is very fast: 50 msec response time. When you power the unit up is ready for use within one second, while capillary concepts take 15 minutes). The instrument does not need the zero adjustments on a regular basis (for capillary MFCs a standard routine). MEMS-based MFCs offer the significantly better reliability of the measured and regulated flow.

Finally, should not mention that the MEMS do need to be appropriately temperature-compensated. The more advanced manufacturers always calibrate their MEMS unit under two different temperatures. During operation, they measure the gas temperature and compensate the MFM/MFC readings, this also contributes to the accuracy and repeatability of the gas measurement/control.


Both concepts have their strong and weaker aspects. The capillary sensor in combination with the LFE leads to a reasonable linear relationship between the flow through the sensor and bypass. Due to this, it is possible to use so-called K-factors, a multiplier factor between two gases. For corrosive gases, the capillary sensor can calibrate with a safe gas like air and apply this K-Factor. In this way, the units can measure reasonable correct with corrosive gas.

However the K-factors calibrations are not always accurate, some MFCs better than others, best is always to calibrate with the real gas, although most capillary manufacturers do not do this. Other plus points are the availability of high-pressure versions and the choice of material for corrosive applications.

For the MEMS-based MFCs, we have better specifications when it comes to accuracy, response time and turndown. MEMS sensor not possible to use of K-factors, hence the MFC need calibration with the real gas of the application. The restriction is that these MFCs not suitable for each gas. Some MEMS manufacturers go a long way to temperature compensate their units; this results in a better accuracy over a more extensive temperature range.

A crucial advantage of the MEMS-based MFCs is the zero drift in the sensor. That results in a better long-term accuracy, repeatability, and reliability.

4 Mass Flow Controller Modular type
Figure 5: Four Mass flow controllers in a customer
specific solution

Typical Applications for Mass Flow Controllers

  • PVD-and other processes in the semiconductor industry
  • The dosage of air, O2, N2, and CO2 in bioreactors
  • Air injection in ice-cream, for a creamy product and best taste
  • Air/O2 dosage used in the fermentation process of beer
  • Gas blending for aerating of food in food packaging applications (MAP: Modified Atmosphere Packaging)
  • Laboratory applications, for instance, analytics and catalyst-research
  • Leakage measurements and permeability research
  • Gas control of glass burners (O2 and fuel) Quality and costs reduction
  • Components testing with the flow/pressure method
  • Metal treatment processes
  • Flow control in analyzers
  • Flushing/blanketing gas
  • Gas consumption measurements of multiple departments in one building/industrial complex
  • Gas dosing in liquid metal purification
  • And many more you can think about …
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How to perform Gas Sampling using Digital Mass Flow Meter?

Gas Sampling using Digital Mass Flow Meter

How to perform Gas Sampling using Digital Mass Flow Meter

The Vögtlin red-y compact 2 meter is used as the heart of a reliable automatic in the analytical world, low-cost gas sample taking the device. Emission or environment measurements often demand periodic sampling of a fixed amount of gas and collect these in a container or sample bag.

For example every hour a 100 scc sample. The red-y compact 2 meter with its optional smart alarm module has the complete solution without the need of any PLC to control the process.

Vogtlin Gas Flow Sampling with Mass Flow Meters
Figure 1

Figure 1 shows a very simplified diaphragm and the system runs on 24 Vdc. Totalizer, the high and low alarm can individually programmable for different alarm functions via the Red-y compact two-alarm module that has three alarm points. The capability to reset the alarms and totalizer and the timer function also utilized with an I/O input on the alarm module.

Program the Alarm 1 as a totalizer alarm with the sample requires a volume to collect in each sample. This example is 100 SCC (Standard cubic centimeter).

Duration of the alarm between 100msec and 2.78 hours programmed in that alarm function, this time sets the time between the samples. Once the process starts, the solenoid will open and a pre-set amount of gas will flow into the sample bag or container. One the defined amount is reached, the Alarm 1 will open and close the solenoid, and the gas flow will stop. Because of the programmed Alarm, 1 duration setting the alarm will stay active for the pre-programmed time, in our example 1 hour.

Once this  hour is over, Alarm 1 is programmed to reset itself automatically, and the counter goes back to zero. The solenoid is activated again, the gas will flow, and the totalizer repeat until the pre-programmed value is reached, the process starts all over again. The process will continue, and every hour one sample of 100 SCC will flow into the sample container.

Diagnostics set in Alarm 3. The alarm will sound if:

  • The sample bag/container gets full
  • Water enters the sample line
  • The flow during sampling is too low (blockage of sample line)
  • The flow is too high (Too high pressure in the process)

In this case, push the reset button to deactivate the alarm and continue the process. There are many other variations possible. Every system is a bit different, you can find additions like purging, filtering, pressure reduction, gas drying, etc. out in the field.
Many of the users of these systems obtain a battery powered high accuracy red-y compact 2 meters to verify if the flow meter in the field is working correctly or if it needs calibration or cleaning. The red-y compact 2 has a significant internal diameter flow channel, has a low-pressure drop, is temperature compensated and measures the mass flow, independent of changes in pressure and temperature.


It is impossible to describe all process in which these type of flow meters are used, but if you see a VA meter for gas and you want to improve a process, talk to the experienced Vögtlin engineers and they will be pleased to help you to find a solution.


Customer around the globe makes use of the advantages in the analytical field, in research and development, in light industrial applications, in semiconductor segments and other forms. Very often we hear from the users “The beauty of the Vögtlin Thermal Mass flow instruments is once you install, set then forget them, as they work so reliable and independently.”
Vögtlin’s worldwide network of distribution and sales partners will help you select most correct equipment that matches specific needs and best for your application.

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6 Features you should know in Vogtlin Red-y Compact Mass Flow Meter

Vogtlin Red-y Compact Mass Flow Meter

Technology brings change in our daily life with the Internet, Cloud, Mobile phone, etc. Process Instrumentation always a feel of old technology without more changes, Vögtlin Instruments brings the Red-y Compact Mass Flow Meter a new design. The improvement helps to provide better “User Experience” even in flow measurement.

The Vögtlin Instruments Red-y Compact honored the “BEST IN FLOW: INNOVATION AWARDS 2016“.

AA Battery Powered Mass Flow Meter/Controller

Battery powered Mass Flow Meter is not a new thing in the industry, but AA Battery makes life much convenient. Most of the Battery Powered Mass Flow Meter will equip with custom-made the battery, which could cost a lot during replacement. The new Vogtlin Red-y Compact powered with 1 AA battery only with battery life as long as six months. The AA Battery even powered the Mass Flow Regulator for flow control.

Touch Screen enabled Mass Flow Meter

Touch Screen Mass Flow Meter

Touch Screen on a Mass Flow Meter is still rare in the market, hence one of the most significant advantages of the touch screen is the direct interaction between user and device. New Vogtlin Red-y Compact are standard with Touch Screen, and parameters setting aren’t hassling anymore.

USB Enabled Mass Flow Meter

Micro-USB power supply Mass Flow Meter
Mass Flow Regulator with USB Powered

Vogtlin Red-y Compact Series is the First USB Powered Mass Flow Meter. Besides the common AA Battery Powered, and 24VDC Powered, the inbuilt Micro USB port allows the user to power the Mass Flow Meter using any USB power source. Portable Mass Flow Meter makes possible with the Micro-USB port with the long hour of flow monitoring, while the port can be used from time to time firmware updates.

Auto Screen Rotating Mass Flow Meter/Controller

Mass Flow Meter hardly replaces Variable Area Flow Meter, which comes from 2 reasons. Pricing & Installation.

Pricing: Mass Flow Meter are generally high cost than Variable Area Flow Meter due to the electronic part and higher accuracy. In demanding industry accuracy is almost equivalent to price. Therefore Mass Flow Meter delivered something that VA Flow Meter not, the accuracy & Stability.

Installation: Mass Flow Meter often display in one direction only (Horizontal or Vertical). However the new upgraded Vogtlin Red-y Compact now capable of rotating the display with 270°. Hence it solves the problem of installation in the VA Flowmeter. The readout of the flow reading now as clear as never before.

Multi Gasses Mass Flow Meter/Controller

Multi Gases Mass Flow Meter

The Vogtlin Red-y Compact can store up to 3 different curves for different gases or gas mixtures in its memory. Gas selection possible from the display if the ordered unit with multiple gases option. The maximum flow rate is shown at the back of every gas name. To purchase Three flow meters for Three different gases, the Red-y Compact save cost with One device for Three gases.

REAL Gas Calibration Mass Flow Meter/Controller

Last but not least in Vogtlin Instruments accuracy is the priority, therefore all Red-y Series Mass Flow Meter out from factory with REAL Gas calibration. The Mass Flow Meter calibrated with REAL gas to ensures high accuracy and reproducibility.

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Variable Area Flow Meter or Mass Flow Meter for Gas Flow Measurements

Variable Area vs Mass Flow

Comparison between Variable Area Flow Meter and Mass Flow Meter often compare of Volumetric Flow and Mass Flow Measurements.

Advantages of Mass Flow Over Volumetric Flow Measurements

  • Mass Flow meter is having widest Turndown Ratio, Fast Response Time, High Accuracy and also High Repeatability
  • Mass Flow Rate independence to pressure and temperature changes
  • Pressure and Temperature Compensation does not require direct Mass Flow Measurements hence improve the cost-effectiveness of gas flow measurement

VA-Flow Meter v.s. Mass Flow Meter

Industrial flow measurements applications often require a higher accuracy together with pressure and temperature compensation which not possible to achieved with conventional Variable Area Flow Meters.

Hence Variable Area Flow Meters are extremely sensitive to pressure and temperature changes. 1 Bar pressure changes in process can generate an error of 50% in gas flow measurements. Therefore the flow compensation of Mass Flow Meters creates repeatability.

Common Variable Area Flow Meter in flow measurement possible only with Vertical Installation, however, smart Digital Mass Flow Meters provide installations flexibility both horizontally and vertically. In the past the Variable Area Flow Meters having great advantages of no power supply required, however with innovation, now Mass Flow Meter with AA Battery Powered available without compromise of measurement accuracy.