Questions You Should Know about Piston Type Circulating Real Gas Flow Standard Device

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INTRODUCTION

Flow measurement is an important process with diverse applications like measuring the flow rate of blood in human beings to measuring and controlling the flow rate in an oil well useful for extraction of oil. It forms an important part of several industries like chemical, wastewater treatment, pulp and paper, oil and gas, and several others. The scope of flow measurement extends far beyond that covered in the following sections. This exhaustive system spans several processes, techniques, and technologies. We have attempted to touch the tip of the iceberg that is flow measurement.

The accuracy of flow measurement determines the functioning of the system. A well-functioning system will provide highly accurate results. Several new technologies are being developed in this realm to support flow measurement systems. These systems as well as direct and indirect processes can help organizations achieve brilliant results.

In this handbook, we will be discussing flow measurement concepts, processes, and systems that are useful to the amateur and professional. They encompass theoretical and practical topics peppered with interesting information and trivia about flow measurement. From the Mesopotamians to Doppler to the most recent group findings, this handbook promises to be an interesting as well as informative read.

WHAT IS FLOW MEASUREMENT?

As the name suggests, flow measurement is the process of measuring the flow rate and volume of a liquid or gas. This process can be employed to measure the liquid passing through an application (as seen in water purification systems), or stored in an application (as seen in fuel injectors). Flow measurement is a vital function used to monitor and control the rate of liquid flow in applications. This process is used to measure the flow of versatile substances like heavy oils, abrasive chemicals, and light gases. Hence, this process is utilized in applications across various industries.

Flow measurement is employed in critical applications where the flow rate or level of liquid stored needs to be administered regularly. The safe functioning of applications depends on flow meters. In terms of flow measurement, accuracy is of such importance that it can be the determining factor of a company making a profit or loss.

WHAT ARE FLOW METERS & THEIR MAIN TYPES?

In some applications, the flow needs to be regulated within a specific range. This is achieved by using flow meters. A flow meter is a device used to facilitate flow measurement. Flow meters are broadly classified as:

1. Differential Pressure
   1. Orifice Plate
   2. Venturi Tube
   3. Flow Tube
   4. Flow Nozzle
   5. Pitot Tube
   6. Elbow Tap
   7. Target
   8. Variable-Area (Rotameter)
2. Positive Displacement
   1. Reciprocating Piston
   2. Oval Gear
   3. Nutating Disk
   4. Rotary Vane
3. Velocity
   1. Turbine
   2. Vortex Shedding
   3. Swirl
   4. Electromagnetic
   5. Ultrasonic, Doppler
   6. Ultrasonic, Transit-Time
4. Mass
   1. Coriolis
   2. Thermal
5. Open Channel
   1. Weir
   2. Flume

UNITS OF FLOW MEASUREMENT

Flow meters can be used to measure the flow rate of liquids or gases. The unit is decided depending on the function and parameters of flow measurement. The unit used varies according to the system of measurement being followed, as well as the material being measured. Dissimilar media need to be measured under diverse conditions and using different units.

Units Used to Measure Flow
The following units are used to measure liquid and gas flow:

• Liquids are measured based on density: liters per second or gallons per minute
• Steam is measured based on weight: Tonnes/ hour and kilograms/ minute
• Gases are measured based on energy content: Joules/ hour and British Thermal Unit/ day
• Gases are also measured according to STP (Standard Temperature and Pressure) and NTP (Normal Temperature and Pressure) in units like m3/hour and acm/ hour (actual cubic meters per hour). Depending on whether the gas is measured at NTP or STP, the units will include the details. Two examples of the symbol at STP and NTP, respectively are: Std m3/hour and Nm3/hour

The unit of measurement changes in accordance with the medium of material being measured. For example, the units of measurement of liquids, gases, and steam could vary. This is because the change in their density is dependent on different factors. The density of gases is dependent on pressure and temperature. On the other hand, the volume of liquid is independent of pressure. Hence, the units used to measure the different media change accordingly.

Flow Measurement &#; A Look Back At History

Mapping the history of fluid dynamics and the flow measurement process, this section takes a look at the milestones achieved.

When: B.C.
Who: Mesopotamians
What: The earliest record of flow measurement can be found in Sumerian cities that were located near the rivers Tigris and Euphrates. The Mesopotamians created channels from the rivers into the city to supply water to every household (an ancient plumbing system, so to say). They used simple methods of flow measurement to monitor the flow rate of water from the rivers into these channels.

When: B.C.
Who: Ancient Egyptians
What: The Nilometer
The Nilometer is a structure that was built to measure water flow throughout the year. This system helped the Ancient Egyptians predict floods, draughts, and well-balanced water flow throughout the season. It also helped them anticipate and prepare their food and supplies according to the volume of water expected in the upcoming season.

When:
Who: Swiss Physicist Daniel Bernoulli
What: Bernoulli published Hydrodynamica, supporting his theory of conservation of energy in liquid flows. This thought process pioneered the processes used to determine pressure drop in various processes and equipment.

When:
Who: Swiss Mathematician and Physicist Leonhard Euhler
What: Euhler applied Newton&#;s Second Law of Motion to fluid dynamics. He developed partial differential equations for motion of fluids.

When:
Who: English Scientist Michael Faraday
What: Faraday invented the theory of the dynamo. He has also been attributed to developing the theory responsible for the invention of the magnetic flowmeter.

When:
Who: Austrian Physicist Christian Doppler
What: Doppler discovered and established a relationship between distance and frequency of sound. Almost a century later, his discovery enabled the invention of the Doppler flow meter.

When:
Who: French Civil Engineer Gaspard Coriolis
What: Coriolis is responsible for discovering the drifting of wind and ocean currents caused by the earth&#;s rotation. This drift varies depending on the location. For instance, the drift is dissimilar at the two poles. The direction of the drift is also dependent on the hemisphere. This has helped further the field of flow measurement greatly.

When:
Who: Irish Mathematician, Physicist, Politician, and Theologian George Gabriel Stokes
What: Based on Claude Navier&#;s calculations and equations published for incompressible fluids, Stokes derived equations that helped describe the motion of liquids. These equations are known as Navier&#;Stokes equations. Stokes also developed theories that led him to invent the Stoke&#;s Law. This law helps calculate drag force in a viscous fluid.

When:
Who: British Engineer Osborne Reynolds
What: He discovered the &#;Reynolds&#;s Number&#;, which is a dimensionless ratio. This number helps us calculate the viscosity of a liquid. This is extremely helpful in flow measurement calculation.

When:
Who: Hungarian-American Aeronautical Engineer Theodore von Karman
What: Karman discovered that the vertices formed in water were always constant irrespective of the velocity of water. His discovery facilitated the discovery of the Vortex flow meter. Based on this principle, the first swirlmeter was made available to the public in .

When:
Who: Hungarian-American Applied Mathematician & Physician John Von Neumann
What: Neumann is regarded as the founding father of computational fluid dynamics. His efforts have helped shape major inventions in the field of fluid dynamics in recent times. His theories on artificial viscosity have also enhanced people&#;s understanding of shock waves.

TRIVIA: What Are Re-discoveries?
Sometimes, when discoveries are made, they are not utilized at that time. There could be several reasons why this happens. Sometimes, people are not able to comprehend the knowledge. At other times, the technology to support the theory has not been developed. Hence, the theory takes a backseat in the minds of people and it can be forgotten over time. When these theories are resurrected, they are known as re-discoveries. For example, when the sub-field of vortex dynamics within the field of fluid dynamics gained momentum, many discoveries and re-discoveries were made.

Why Measure Flow?

It is obvious that wherever needed, flow meters are critical to the functioning of the application. In fact, in some applications, precise measurement of liquid and gases is needed to maintain safety. However, one too many times, flow meters are installed when they are not needed. At other times, the requirements of the application are not assessed correctly. This causes several problems in terms of functionality, not to mention misdirection of company funds.

Flow meters can be used in conjunction with several types of liquids. Various configurations of these devices are available, which allow them to be used with liquids with varying chemical and physical properties. In terms of configurations, the flow meters can be designed with various functionalities, materials, and capacities. The specifications can be customized according to the needs of the application and industry.

For example, specialized flow meters are available for use in wastewater treatment plants. The material used for the construction of the flow meter will vary depending on the pH levels of the water. In addition, the flow meter will have to be designed to accommodate the inflow of the water. In order to ensure maximum accuracy, the capacity of the flow meter should match that of the wastewater flowing through the system.

Factors to Consider When Selecting a Flow Meter

A market survey has claimed that over 75% of industrial flow meters are not performing up to the expected mark. This is mainly caused due to improper product selection. In the initial stages of product selection, buyers can benefit from understanding the basic requirements of their applications. To do this, the right questions need to be asked.

Some tips to help you define your requirements:
Most Important Flow Meter Functions are:

1. Repeatability
2. Accuracy
3. Range
4. Linearity

QUESTIONS YOU SHOULD BE ASKING
Do I Need?

1. Local or Remote Operation
2. Local or Remote Output

Is The Liquid Being Measured:

1. Viscous?
2. Clean?
3. Slurry?
4. Electronically Conductive?

Also..

1. What is the density of the liquid?
2. What is the expected flow rate?
3. What will be the operating temperature?
4. How much pressure is the device expected to handle?
5. What is your budget?

Flow Meter Features that Increase Efficiency
Look for the following features within your application to ensure maximum efficiency:

• Construction should ensure:
  • Insusceptibility to vibration
  • Durability
  • Stable output
  • Resistance to corrosion and abrasion
  • Safe operation
  • Small carbon footprint
  • Ease of installation
• Should feature drainability for:
  • Low maintenance intervals and costs
  • Maximizing uptime
  • Improved accuracy
• The following feature adds value to the application:
  • Automatic corrosion resistance features, which help in detection of defect or failure in components (like pipes)

Every product has its own advantages and disadvantages. It is important to match your application&#;s requirements with those of the flow meter. When the features and needs of both are in harmony, the results are outstanding. Manufacturers and suppliers, alike are eager to assist buyers in their quest to finding the perfect flow meter that delivers on all counts of performance and efficiency.

Flow Meter Management: Calibration

Flow meter calibration along with other installation and maintenance procedures is needed to ensure safe operation of plants. Flow meters analyze a very important function. Hence, before purchasing a flow meter, the buyer should consider whether the device can be installed, used, and maintained in the best possible manner.

Why Calibrate?
Flow meters are used in critical applications and functions. Hence, they need to be calibrated to ensure accurate measurements. With constant use, components wear out and flow meters can fall out of calibration. This is true for the most ruggedly constructed devices. The accuracy of the measurement reduces over time. Regular calibration will ensure that all components function efficiently, providing brilliant results.

Common Problems that Demand Regular Calibration
Why should one calibrate? Here are some problems that could occur with a flow meter. These problems disrupt the functioning of machines. However, they can be solved by employing calibration methods. Some of the problems you should watch out for:

1. Deposits : Dirt, salt, minerals, and foreign materials can be deposited on the interior surfaces of the machine. This disrupts the functioning of the instrument. Even if the machine seems to be functioning well on the outside, internal deposits can cause major problems to the functionality of the flow meter.
2. Contamination : Several problems can occur if the material within the flow meter is contaminated. For instance, the intricate parts within the flow meter could be blocked causing the entire operation to shut down. Careful testing of the material flowing within the device should be carried out. In some cases, the problem could lie with the device itself. Hence, regular maintenance should be conducted to identify possible areas and reasons for contamination.
3. Abrasion : When harsh chemicals are used, the surface of the equipment could wear out. You must keep your flow meter safe from chemical attacks.
4. Natural Wear & Tear : Every product has a life span. Beyond a certain time or magnitude of usage, natural wear and tear will cause aging. Certain components within the flow meter will have to be changed after a certain period. This information will be provided by the manufacturer. Changing the components at the right time will ensure a longer life cycle of the flow meter.
5. Unsuitable Treatment : If the machine is not used in accordance with the manufacturer&#;s directives, some parts or the machine as a whole will stop functioning. On a smaller scale, the performance of the machine will be altered. One way or another, the machine should not be abused.
6. Improper Installation : Some problems associated with the flow meter can be traced to the installation procedures. This will also lead to inconsistencies between the functioning and calibration of the flow meter.
7. External Influences : The environment of the application and the natural environment both will have some effect on the functioning of the flow meter. The functioning of the flow meter could be affected by electromagnetic radiation, vibrations, temperature and pressure changes, etc.
8. Difference in Fluid Properties : A flow meter will function optimally when used with the liquid or gas with which it was calibrated. If there is a major inconsistency in the liquid used, the flow meter will fail to provide accurate results.

Best Practices of Flow Meter Calibration at a Micro Level
(Conducted at the Execution Level)
When calibrating flow meters, the following practices will allow you to get the most out of the process:

1. Accuracy of Standard : It is a good practice to make sure that your standard is extremely accurate. The norm is to keep the accuracy of the standard four times higher than the Unit Under Test (UUT). Depending on the application, this thumb rule could vary.
2. Traceability of Standard : As with all best calibration practices for most equipment, the standard used to calibrate your equipment should be traceable to a known standard. Traceability is important to verify your measurements. It also helps define the accuracy of your calibration process.
3. Real Time Calibration : Since the calibration process is conducted in real time, the flow rate of the flow meter should not vary. The flow between the standard and test equipment should be constant throughout the calibration process.
4. Physical Conditions :The physical conditions during the functioning of the standard and test flow meter should not vary. A slight change in the temperature or pressure conditions can cause a major disruption in the calibration process leading to errors. You must also ensure that there are no leaks, change in volume, or change of medium/ material.
5. Real Time Conditions: The tests should be carried out in conditions that will be present during the functioning of the flow meter. This will help you accurately match the application&#;s requirements.
6. Multiple Testing :Multiple tests should be conducted to verify your initial findings. If there is a major difference in the findings, you will need to validate the accuracy of your standard and other processes and equipment being used.

Industrial Dynamics Tip :
During the calibration process, the common error zone lies in the medium being measured. This zone comes in play when there is some difference between the liquid&#;s viscosity, density, or heat content at both the stages of testing.
For example, if the density of the liquid is slightly higher during the operation of the standard as compared to the density of the liquid during the operation of the test flow meter, your results will be inaccurate.

Best Practices of Flow Meter Calibration at a Macro Level
(Conducted at a Company Level)
The following practices should be employed by a company on a macro level. It is the responsibility of the managerial function of an organization to put these processes in place:

1. Scheduled Calibration : A regular calibration schedule should be in place. All flow meters should be calibrated in accordance with the time of operation or life cycle of product.
2. Accessible Calibration Data : When a flow meter is calibrated, all data should be carefully recorded. This information should be readily accessible to the person in charge. Hence, at one glance, the technician will know when and what changes were made to the device. This will allow them to get an insight into the maintenance procedures implemented on the product.
3. Certified Laboratory : If using a calibration lab, ensure that they possess the right experience and certifications. You must also not shift from one lab to another as the calibration methods or standards may defer making it difficult for you to draw a comparison between the two.
4. Reducing Down Time : Down time is a natural occurrence of the calibration process. You can reduce or even diminish this down time by purchasing spare flow meters. Rotating the flow meters will also ensure better functioning and allow tracking comparisons in the functioning of two flow meters.

Although the calibration of most flow meters will fall out at some time due to wear and tear of components, the calibration could also be off due to improper installation or damaged components. Hence, regular calibration will ensure that the flow meter functions smoothly providing precise results.

Industries Benefitting From Flow Meters

Flow meters are used across several industries. Following are some examples of industries and applications, which use flow meters to accurately monitor and measure different liquids:

1. Industry: Chemical
   Application: Monitoring Flow of Chemicals
2. Industry: Oil & Gas
   Application: Measuring the Rate of Flow of Crude Oil
3. Industry: Pulp & Paper
   Application: Measuring Pulp Stock
4. Industry: Petrochemical
   Application: Measuring Fuel Flow in Commercial Applications
5. Industry: Food & Beverage
   Application: Wine Filling
6. Industry: Refining
   Application: Pump Monitoring
7. Industry: Pharmaceutical
   Application: Production and Packaging of Liquids
8. Industry: Waste & Wastewater
   Application: Measuring Wastewater Flowing into Water Filtration Systems
9. Industry: Power & Energy
   Application: Deionised Flow Measurement
10. Industry: Agriculture
    Application: Monitoring Water Used for Irrigation

CONCLUSION

Several specifications of the application and flow meter have to be considered when finding the right fit. Several external factors including environmental conditions, budget, etc. also need to be taken into consideration during product selection. Factors such as the media to be measured, viscosity of media, operating conditions (like temperature and pressure), performance expectation, installation conditions, and material of the flow meter need to be paid attention to when selecting a flow meter. The right product will help improve efficiency of the entire process. You can even consult your manufacturer on the best kind of product that will integrate seamlessly with the rest of your system.

The maintenance of the product throughout its service life cycle should be taken into consideration when outlining the budget for the product. This will reduce the surprise factor and help you in planning your finances accordingly. Regular calibrations, among other maintenance procedures are needed to ensure proper functioning of your flow meter. Calibration, as most flow meter owners understand is an important process that helps mitigate any issues associated with performance. Maintaining the accuracy of a flow meter has to be the top most priority of any organization.

Discussion of several such important topics is the need of the hour, as every organization is looking for solutions to flow measurement issues. Understanding the basics will allow you to select, purchase, and handle the instrument better. Flow measurement knowledge is also useful in increasing the efficiency of your products.

Flow measurement is important for environmental sustainability, increased efficiency, safety, and process optimization.

So far, there are as many as 60 Flow Meter Types available for industrial use. The reason why there are so many varieties is that so far we have not found a flow meter that is suitable for any fluid, any range, any flow state and any use conditions.

Each of these 60 kinds of flow meters has its specific applicability and limitations. According to the measurement principles, there are mechanical principles, thermal principles, acoustic principles, electrical principles, optical principles, atomic physics principles, etc. According to the most popular and extensive classification method at present, it is divided into: volumetric flowmeter, differential pressure flowmeter, float flowmeter, turbine flowmeter, electromagnetic flowmeter, vortex flowmeter, ultrasonic flowmeter, mass flowmeter wait.

Here we have selected the 11 most commonly used flow meters to introduce and analyze their advantages and disadvantages.

We have introduced the definition of flow measurement and flow meter in the blog &#;Flow Measurement 101&#;. If you are a newbie, you can refer to it.

Next, let&#;s take a look at 11 Flow Meter Types and Their Advantages and Disadvantages.

Electromagnetic Flowmeter

working principle

The electromagnetic flowmeter is an instrument for measuring conductive liquids based on Faraday&#;s law of electromagnetic induction. Electromagnetic flowmeters have a series of excellent characteristics that can solve problems that are difficult to apply with other flowmeters, such as the measurement of dirty flows, mud, and corrosive flows.

advantages and disadvantages

Advantage:

• The measurement channel is a smooth straight tube and will not be blocked. Suitable for measuring liquid-solid two-phase fluids containing solid particles, such as pulp, mud, sewage, etc.;
• There is no pressure loss caused by flow detection, and the energy saving effect is good;
• The measured volumetric flow rate is virtually unaffected by changes in fluid density, viscosity, temperature, pressure and conductivity;
• Large flow range and wide caliber range;
• Corrosive fluids can be used.

Disadvantages:

• Liquids with very low conductivity, such as petroleum and oil products, cannot be measured;
• Cannot measure gas, steam and liquids containing large bubbles;
• Cannot be used at higher temperatures.

Applications

Electromagnetic flowmeters have a wide range of applications.

Large-diameter instruments are mostly used in water supply and drainage projects.

Small and medium diameters are often used in high-demand or difficult-to-measure situations, such as blast furnace tuyere cooling water control in the steel industry, measurement of pulp liquid and black liquor in the papermaking industry, strong corrosive liquids in the chemical industry, and slurry in the nonferrous metallurgical industry.

Small diameter and micro diameter are often used in the pharmaceutical industry, food industry, biochemistry and other places with hygienic requirements.

Electromagnetic flowmeter can also be used for Partially Filled Pipe flow measurement.

Learn more about Magnetic Flowmeter Technology and choose Magnetic Flow Meters for your applications.

Turbine flowmeter

working principle

Turbine flowmeter is the main type of velocity flowmeter. It uses a multi-blade rotor (turbine) to sense the average flow velocity of the fluid and derive the flow rate or total amount.

Generally, it consists of two parts: sensor and display, and can also be made into an integral type.

advantages and disadvantages

Advantages:

• High precision, among all flow meters, it is the most accurate flow meter;
• Good repeatability;
• Zero point drift, good anti-interference ability;
• wide range;
• Compact structure.

Disadvantages:

• Unable to maintain calibration characteristics for a long time;
• Fluid physical properties have a great influence on flow characteristics.

Applications

Turbine flowmeters are widely used in the following measurement objects: petroleum, organic liquids, inorganic liquids, liquefied gases, natural gas and cryogenic fluids. In Europe and the United States, turbine flowmeters are second only to orifice flowmeters in terms of natural measurement meter.

If you want to learn more, please visit our website tnma.

Learn more about Turbine Flowmeter Technology and choose Turbine Flow Meters for your applications.

Vortex flowmeter

working principle

The vortex flowmeter is an instrument in which a non-streamlined vortex generator is placed in the fluid. The fluid alternately separates and releases two series of regularly staggered vortexes on both sides of the generator.
Vortex flowmeters can be divided according to frequency detection methods: stress type, strain type, capacitive type, thermal type, vibration type, photoelectric type and ultrasonic type, etc.

advantages and disadvantages

Advantages:

• Simple and solid structure;
• Applicable to many types of fluids;
• Higher accuracy;
• Wide range;
• The pressure loss is small.

Disadvantages:

• Not suitable for low Reynolds number measurements;
• A longer straight pipe section is required;
• Lower instrument coefficient (compared to turbine flowmeter);
• The instrument still lacks application experience in pulsating flow and multi-phase flow.

applications

Vortex flowmeter is suitable for measuring various liquid media, such as water, petroleum, chemicals, solutions, etc.
At the same time, it is also suitable for measuring various gas media, such as air, natural gas, nitrogen, etc.
In addition, vortex flowmeters can also be used to measure steam flow.

Vortex flowmeters can measure over a wide temperature and pressure range. Generally, vortex flow meters can adapt to the temperature range from -200°C to +400°C and the pressure range from vacuum to high pressure.

Learn more about Vortex Flowmeter Technology and choose Vortex Flow Meters for your applications.

Ultrasonic flow meter

working principle

Ultrasonic flowmeter is an instrument that measures flow by detecting the effect of fluid flow on ultrasonic beams (or ultrasonic pulses). According to the principle of signal detection, ultrasonic flowmeters can be divided into propagation velocity difference methods (direct time difference method, time difference method, phase difference method and frequency difference method), beam offset method, Doppler method, cross-correlation method, and spatial filtering method. and noise method, etc.

Ultrasonic flowmeters are the same as electromagnetic flowmeters. Because there are no obstructions in the flow channel of the instrument, they are both unobstructed flowmeters. They are a type of flowmeter suitable for solving difficult problems of flow measurement, especially in large-diameter flow measurement. The advantages.

advantages and disadvantages

Advantages:

• Non-contact measurement is possible;
• Measurement without flow obstruction and no pressure loss;
• It can measure non-conductive liquids and is a supplement to the electromagnetic flowmeter for non-obstruction measurement.

Disadvantages:

• The travel time method can only be used for clean liquids and gases; while the Doppler method can only be used to measure liquids containing a certain amount of suspended particles and bubbles;
• The measurement accuracy of Doppler method is not high.

Application

The transit time method is applied to clean, single-phase liquids and gases. Typical applications include tap water, diesel, etc.
In terms of gas applications, we have good experience in the field of high-pressure natural gas;
The Doppler method is suitable for two-phase fluids with a low heterogeneous content. For example: raw sewage, factory effluents, dirty process fluids; generally not suitable for very clean liquids.

Learn more about Ultrasonic Flow Meter Technology and choose Ultrasonic Flow Meters for your applications.

In addition to being used in flow measurement, ultrasonic technology has also been applied to liquid level measurement, providing an excellent liquid level measurement solution!

Coriolis mass flow meter

working principle

Coriolis mass flow meter This flow meter is a novel instrument that directly and precisely measures fluid mass flow. The main structure uses two side-by-side U-shaped tubes, and the bent parts of the two tubes vibrate slightly toward each other, and the straight tubes on both sides will vibrate accordingly. That is, they will move closer or open at the same time, that is, the vibrations of the two tubes are synchronous and symmetrical.

If the fluid is introduced into the tube and flows forward along the tube while the tube is vibrating synchronously, the tube will force the fluid to vibrate up and down with it.

advantages and disadvantages

Advantages

• Coriolis mass flow meters directly measure mass flow and have high measurement accuracy.
• A wide range of measurable fluids. Various liquids including high viscosity liquids, slurries containing solids, liquids containing trace amounts of gas, and medium and high pressure gases with sufficient density.
• The vibration amplitude of the measuring tube is small and can be regarded as an inactive part. There are no obstructions and movable parts in the measuring pipeline.
• It is not sensitive to the upstream flow velocity distribution, so there is no requirement for upstream and downstream straight pipe sections.
• The measured value is insensitive to fluid viscosity, and changes in fluid density have little impact on the measured value.
• Can perform multi-parameter measurements. Just like measuring density, temperature, and derived from this measure the concentration of solute contained in a solution.

Disadvantages

• The zero point of the Coriolis mass flowmeter is unstable and causes zero point drift, which affects the further improvement of its accuracy. As a result, many models of instruments have to divide the total error into two parts: basic error and zero-point instability measurement.
• Coriolis mass flow meters cannot be used to measure low-density media and low-pressure gases. The gas content in the liquid above a certain limit (varies by model) can significantly affect the measured values.
• Coriolis mass flow meters are sensitive to external vibration interference. In order to prevent the influence of pipeline vibration, most models of Coriolis mass flow meters have relatively high requirements for installation and fixation of flow sensors.
• It cannot be used for larger pipe diameters, currently limited to less than 200mm.
• Wear, corrosion or sedimentation of the inner wall of the measuring tube will affect the measurement accuracy. This is especially true for Coriolis mass flow meters with thin-walled tube measuring tubes.
• Most models of Coriolis mass flow meters are heavy and bulky.
• expensive. The ordinary price is 5,000 to 10,000 US dollars for a set, which is about 2 to 8 times that of electromagnetic flowmeters of the same caliber.

Applications

Coriolis mass flow meters are the best choice for applications like:

• Food & Beverage
• Pulp and paper
• Petrochemical
• Oil & Gas
• Power
• High Viscosity
• Paint
• Mining
• Process Control
• Water and wastewater
• And numerous other industries

Learn more about Coriolis Mass Flow Meter Technology and choose Mass Flow Meters for your applications.

Thermal mass flow meter

working principle

Thermal flow meter sensors contain two sensing elements, a speed sensor and a temperature sensor. They automatically compensate and correct for gas temperature changes.

The electric heating part of the instrument heats the speed sensor to a certain value higher than the working temperature, so that a constant temperature difference is formed between the speed sensor and the sensor that measures the working temperature. When the temperature difference is kept constant, the energy consumed by electric heating, which can also be said to be the heat dissipation value, is proportional to the mass flow rate of the gas flowing through it.

advantages and disadvantages

Advantages

• High reliability
• Good repeatability
• High measurement accuracy
• Small pressure loss
• No moving parts
• Range ratio wide
• quick response
• No temperature and pressure compensation required

Disadvantages

• Due to changes in cp value and thermal conductivity, the measured value will change greatly and cause errors;
• If the gas being measured is scaled on the tube wall, it will affect the measured value, and it has the disadvantage of being easily blocked;
• Thermal mass flow meters for pulsating flows and liquids will be limited in their use for viscous liquids.
• The gas is required to be dry and pollution-free: Gas with high humidity affects the heat exchange on the sensor surface, which in turn affects the output results. Particulate matter also has an impact on sensor output.
• Not suitable for high viscosity gases: For high viscosity gases, the performance of the thermal gas mass flow meter may be affected. Because the heat transfer characteristics of the gas will change.

Applications

Thermal gas mass flow meter is a new instrument used to measure and control gas mass flow.

• Gas mass flow measurement in industrial pipelines
• Measurement of flue gas flow rate from chimney
• Calciner flue gas flow measurement
• Air flow measurement in gas process
• Compressed air flow measurement
• Gas flow measurement during half-channel body chip manufacturing process
• Gas flow measurement in sewage treatment
• Gas flow measurement in heating ventilation and air conditioning systems
• Flux recovery system gas flow measurement
• Combustion gas flow measurement in combustion boilers
• Gas flow measurement of natural gas, flare gas, hydrogen and other gases
• Carbon dioxide gas flow measurement during beer production
• Gas mass flow measurement in the production process of cement, cigarette and glass factories

Learn more about Thermal Mass Flow Meter Technology and choose Thermal Mass Flow Meters for your applications.

Volumetric flow meter

working principle

Positive displacement flowmeter, also known as fixed displacement flowmeter, or PD flowmeter for short, is the most accurate type of flow meter.

It uses mechanical measuring elements to continuously divide the fluid into a single known volume part. The total volume of the fluid is measured based on the number of times the measuring chamber is filled and discharged with the fluid in this volume part.

Volumetric flowmeters are classified according to their measuring components and can be divided into oval gear flowmeters, scraper flowmeters, double rotor flowmeters, rotating piston flowmeters, reciprocating piston flowmeters, circular gear flowmeters, and liquid-sealed rotary drum flowmeters. , wet gas meter and membrane gas meter, etc.

advantages and disadvantages

Advantages:

• High measurement accuracy;
• Installation pipeline conditions have no impact on measurement accuracy;
• Can be used for measurement of high viscosity liquids;
• wide range;
• The direct-reading instrument can directly obtain the accumulation and total quantity without external energy, which is clear and easy to operate.

Disadvantages:

• The results are complex and bulky;
• The type, caliber, and working status of the medium to be measured have great limitations;
• Not suitable for high and low temperature situations;
• Most instruments are only suitable for clean single-phase fluids;
• Produces noise and vibration.

Applications

Volumetric flowmeters, differential pressure flowmeters and float flowmeters are among the three most commonly used flowmeters and are often used for total volume measurement of expensive media (oil, natural gas, etc.).

Learn more about Volumetric Flow Meters: Comprehensive Guide and Product List.

Differential pressure flow meter

working principle

A differential pressure flowmeter is an instrument that calculates flow based on the differential pressure generated by the flow detection component installed in the pipeline, the known fluid conditions, and the geometric dimensions of the detection component and the pipeline.

The differential pressure flow meter consists of a primary device (detection component) and a secondary device (differential pressure conversion and flow display instrument). Differential pressure flowmeters are usually classified in the form of test pieces, such as orifice flowmeters, Venturi flowmeters, velocity-averaging tube flowmeters, etc.

The secondary devices are various mechanical, electronic, electromechanical integrated differential pressure gauges, differential pressure transmitters and flow display instruments.

The detection parts of differential pressure flow meters can be divided into several categories according to their working principles: throttling device, hydraulic resistance type, centrifugal type, dynamic head type, dynamic head gain type and jet type.

advantages and disadvantages

Advantages:

• The most widely used orifice flow meter has a solid structure, stable and reliable performance, and long service life;
• It has such a wide range of applications that no other type of flow meter can compare with it so far;
• The detection parts, transmitters, and display instruments are produced by different manufacturers to facilitate production with economies of scale.

Disadvantages:

• Measurement accuracy is generally low;
• The range is narrow, generally only 3:1~4:1;
• The requirements for on-site installation conditions are high;
• Large pressure loss (referring to orifice plate, nozzle, etc.).

Applications

• Differential pressure flow meters have a particularly wide range of applications. Various objects have applications in flow measurement of closed pipes.
• For example, in terms of fluids: single phase, mixed phase, clean, dirty, viscous flow, etc.;
• Working status: normal pressure, high pressure, vacuum, normal temperature, high temperature, low temperature, etc.;
• In terms of pipe diameter: from several mm to several meters;
• Flow conditions: subsonic, sonic, pulsating flow, etc.

Learn more about Differential Pressure Flow Meter Technology and choose Differential Pressure Flow Meters for your applications.

Float flowmeter

working principle

The float flowmeter, also known as the rotor flowmeter, is a type of variable area flowmeter. In a vertical tapered tube that expands from bottom to top, the gravity of the float with a circular cross-section is borne by the liquid power, so that the float Can rise and fall freely within the conical tube.

The float flowmeter plays a decisive role in small and micro flow.

advantages and disadvantages

Advantages:

• The glass cone tube float flowmeter has a simple structure and is easy to use.
• Suitable for small pipe diameters and low flow rates;
• Pressure loss is low.
• Good stability: Since the measuring element of the float flowmeter is not in direct contact with the fluid, it will not be affected by changes in the physical properties of the fluid and has good stability.

Disadvantages are low pressure resistance and a greater risk of the glass tube being fragile.

Metal rotor flowmeter

working principle

The float of the metal tube rotor flowmeter is in the measuring tube. As the flow rate changes, the float moves upward. At a certain position, the buoyancy force on the float and the gravity of the float reach a balance.

At this time, the flow annular area between the float and the orifice plate (or tapered tube) remains constant. The annulus area is proportional to the rising height of the float. That is, the rising position of the float in the measuring tube represents the flow rate. The changing position of the float is transmitted to the external indicator by the internal magnet, allowing the indicator to correctly indicate the flow value at this time. .

This prevents the indicator housing from being in direct contact with the measuring tube. Therefore, even if a limit switch or transmitter is installed, the instrument can be used under high temperature and high pressure working conditions.

advantages and disadvantages

Advantages:

• Sturdy, simple, reliable, with low maintenance and long life.
• Modular, intelligent, indicator design.
• The requirements for the downstream straight pipe section are not high.
• It has a wide flow range of 10:1.
• Short stroke, small structure design.
• Realize soft output through HART to display instantaneous and cumulative flow. Switch signal output, on-site setting and adjustment of media parameters, on-site performance compensation.
• Multi-level correction of medium viscosity, density, temperature and pressure.
• There are many types such as local type, remote transmission type, jacket type, explosion-proof, corrosion-resistant type, sanitary type, etc.
• Stainless steel, Hastelloy, titanium, and PTFE material measurement systems are available.
• Low pressure loss design.
• Vertical, horizontal and various installation methods are more suitable for different use occasions.
• All-metal structure, suitable for high temperature, high pressure and highly corrosive media.
• Can be used in flammable and explosive hazardous locations.

Disadvantages:

• The application of float flowmeter is limited to small and medium pipe diameters. It cannot be used for large pipe diameters, and the maximum diameter is generally DN150mm.
• When the fluid used is different from the factory calibration fluid, the flow indication must be corrected. Float flowmeters for liquids are usually calibrated with water, and gases with air. If the density and viscosity of the actual fluid used are different, the flow rate will deviate from the original graduation value, and conversion corrections must be made.

Applications

Metal tube float flowmeter is a variable area flow measurement instrument commonly used in industrial automation process control.

Can be used to measure the flow of liquids, gases and steam. It is especially suitable for medium flow measurement with low flow rate and small flow rate. Commonly used are water and air measurements.

open channel flow meter

working principle

The working principle of the open channel flowmeter is to use open channel technology to measure the fluid level and then calculate the flow rate through the microprocessor inside the instrument.
Due to non-contact measurement, open channel flow meters can be used in harsher environments.

Under the control of a microcomputer, the open channel flowmeter transmits and receives the open channel, and calculates the distance between the open channel flowmeter and the measured liquid surface based on the transmission time, thereby obtaining the liquid level height. Since there is a certain proportional relationship between the liquid level and the flow rate, the liquid flow rate Q can be finally obtained according to the calculation formula.

advantages and disadvantages

Advantages:

• The measurement range is large, and the flow measurement is not affected by the return water on the tributary surface.
• During measurement, it is not affected by sediment, bubbles and large changes in water level floating in the water. The flow sensor produces resistance to the flow of water. It has a simple structure, small size and is easy to install.
• Standard channels can be installed directly without modification, and the installation and construction costs are low.
• The instrument has complete display and output functions. It can display measurement data such as water level, flow velocity, flow rate, cumulative flow rate, etc. It also has an RS-485 communication interface.
• It has alarm functions for water level, mud level and flow rate exceeding limits.
• It has a data saving function that can save setting parameters and flow values in the event of a long-term power outage.

Disadvantages:

• In actual use, changes in water quality will affect the measurement results, especially when the water contains suspended matter or sediment with larger particles, which will cause the flow meter to become clogged or the readings will be inaccurate;
• In open watercourses, channels or drainage systems this requires extensive excavation work.
• Not suitable for high viscosity fluids.
• Parshall troughs and weir troughs, etc. need to be installed;
• A certain amount of installation space is required;
• A mounting bracket is required.

Applications

Ultrasonic open channel flowmeter is suitable for measuring the flow of rectangular, trapezoidal and U-shaped open channels in reservoirs, rivers, water conservancy projects, urban water supply, sewage treatment, farmland irrigation, water administration and water resources.

Ultrasonic open channel flow meters need to be measured together with weirs and troughs. Commonly used weirs and troughs include Parshall troughs, rectangular troughs, triangular weirs, etc. The appropriate matching method can be selected according to different site environments.

Understanding the various types of flow meters is only half the battle in choosing the right one for you. You can learn more details in our flow meter selection guide to choose the best flow meter for your measurement!

More Flow Measurement Solutions

We at Sino-Inst produce and supply common industrial flow meters, including: electromagnetic flow meters, turbine flow meters, vortex flow meters, ultrasonic flow meters, Coriolis mass flow meters, oval gear flow meters, non-full tube electromagnetic flow meters, etc. More than 50 species.

Our flow meters are widely used in production and processes in various industries. Including customization for high temperature, extremely low temperature, high viscosity, corrosion and other special media measurements. If you need to purchase a flow meter or have any questions, please feel free to contact us.

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