Approaches To Gas Flow Measurement: Types and Applications Of Gas Flow Meters

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Approaches To Gas Flow Measurement

Gas flow measurement is an essential technology in many industrial processes. For example, in the production of chemical products, accurate measurement of the flow of gases such as oxygen and nitrogen can ensure that the reactants are added to the reactor in the appropriate proportion to obtain high-quality products.

RFQ

Introduction: Why Gas Flow Measurement is Important

The measurement of air and other gases in manufacturing plants in the chemical process industries (CPI) is essential in many constructive applications. Including safety, process control, product quality, production efficiency, environmental conformity and costs.

When the measurement of air or other gases is imprecise or inconsistent, some potential outcomes include serious accidents, emergency shutdowns, unplanned maintenance, production slowdowns or cost overruns.

There are 6~8 viable flow measurement technologies for gases available today. But only about half of them are suitable for the heavy-duty metering applications found in the most challenging CPI operations.

Each technology has its own strengths and weaknesses, depending on exactly what material needs to be measured, the required accuracy, where it needs to be measured and so on.

The truism “knowledge is power” definitely applies when it comes to choosing a flow meter for gas measurement tasks. The same flow-sensing technology that is chosen for one application in a plant is quite possibly the wrong choice in a different exercise — even one that is in close proximity within a facility.

The cost of deciding the wrong flow meter — in terms of extra maintenance, repairs and spares in large CPI plants is huge.

Parameters to Consider When Choosing a Gas Flow Meter

Selecting the suitable gas flow meter depends on several components, including:

  • Type of Gas
  • Flow information
  • Flow Rate
  • Process Conditions
  • Pressure
  • Temperature
  • Accuracy Requirements
  • Installation and Maintenance

Types of Gas Flow Meters in detail

SI-3301 Gas Vortex Flow Meter
SI-3301 Gas Vortex Flow Meter
SI-3304 Insertion Type Vortex Flow Meter
SI-3304 Insertion Type Vortex Flow Meter
Rotameter Flow Meters-Metal Variable Area Flow Meters
Rotameter Flow Meters-Metal Variable Area Flow Meters
SI-3305 Intelligent Gas Precession Vortex Flowmeter
SI-3305 Intelligent Gas Precession Vortex Flowmeter
SI-3201 GAS Turbine Flow Meter
SI-3201 GAS Turbine Flow Meter
SI-3503 Gas Mass Flow Meter
SI-3503 Gas Mass Flow Meter
SI-3701 Orifice Plate Flow Meter
SI-3701 Orifice Plate Flow Meter
SI-3702 Annubar Flow Meter
SI-3702 Annubar Flow Meter

Gas flow meters come in various designs and technologies, each suited for specific applications. The main types of gas flow meters include:

  • Differential Pressure Flow Meters
  • Thermal Mass Flow Meters
  • Ultrasonic Flow Meters
  • Turbine Flow Meters
  • Vortex Flow Meters

Differential Pressure Flow Meters

Differential pressure flow meters measure the flow of gas by calculating the pressure drop over an obstruction placed in the flow path. Common types include orifice plates, flow nozzles etc.

Thermal Mass Flow Meters

Thermal mass flow meters measure the flow of gas based on the law of heat transfer. These meters are perfect for measuring low flow rates and are often used in applications such as HVAC systems, biogas monitoring, and industrial gas flow measurement.

Ultrasonic Flow Meters

Ultrasonic flow meters use sound waves to measure the velocity of gas flow. There are two main kinds: transit-time and Doppler. Ultrasonic flow meters are non-intrusive and are ideal for applications where the gas flow needs to be measured without disrupting the process.

Turbine Flow Meters

Turbine flow meters measure the gas flow by using a rotor placed in the flow stream. These meters are suitable for clean, non-corrosive gases and are commonly used in natural gas pipelines and HVAC systems.

Vortex Flow Meters

Vortex flow meters measure the flow rate of gas by detecting the vortices shed by a bluff body placed in the flow stream. Vortex meters are versatile and can handle a wide range of gases, making them appropriate for applications in the chemical, petrochemical, and energy industries.

SI-3305 Intelligent Gas Precession Vortex Flowmeter

Inline vs. Insertion Gas Flow Meter

An in-line gas flow meter has a flow line installed in a process line and has a built-in flow conditioner that enhances the profile of the process gas. Here we use a thermal gas flow meter Take for example, the comparison of inline and insertion style flow meters.

AttributesInline gas flow meterInsertion gas flow meter
ConfigurationThe inline or in-line gas flow meter includes a flow body installed more permanently in a process line.   In this configuration, the meter’s probe inserts into the process pipe.
AdvantagesOne of the in-line meter advantages is that it does not need as much of a straight run as the insertion-style meter permitting the end-user to cut down the length of the upstream straight run to three pipe diameters in most cases. One of the important advantages of the insertion-style meter is the ease of installation; additionally, the style has an captivating price.
UsagesThis meter configuration has a built-in flow conditioner that optimizes the flow profile of the process gas.The insertion-style thermal gas flow meter is appropriate for temporary or semi-permanent gas flow measurement.

Mass Gas Flow Meters

Mass gas flow meters are specifically designed to measure the mass flow rate of gases, rather than just the volumetric flow. This is particularly important in applications where the density of the gas may vary due to changes in temperature and pressure. There are two main types of mass gas flow meters: thermal and Coriolis.

Thermal Mass Flow Meters

As mentioned earlier, thermal mass flow meters measure the gas flow based on heat transfer principles. These meters are highly sensitive to low flow rates and provide accurate measurements even in fluctuating process conditions.

Thermal mass flow meters are commonly used in applications such as:

  • Biogas Monitoring: To measure the flow of biogas produced in anaerobic digestion processes.
  • HVAC Systems: For monitoring airflow in heating, ventilation, and air conditioning systems.
  • Industrial Gas Flow Measurement: In various industries to measure gases such as nitrogen, oxygen, and carbon dioxide.
SI-3305 Intelligent Gas Precession Vortex Flowmeter

Coriolis Mass Flow Meters

Coriolis mass flow meters offer high accuracy and can measure both mass flow and gas density. They are ideal for applications requiring precise measurement and control, including:

  • Chemical Processing: To measure the flow of reactants and products in chemical reactions.
  • Natural Gas Measurement: For custody transfer and distribution of natural gas.
  • Food and Beverage Industry: To monitor the flow of gases used in carbonation and packaging processes.

Gas Flow Measurement Solutions

Sino-Inst can provide customized gas flow measurement solutions for different gases and different application conditions.

Natural gas is a colorless and odorless hydrocarbon and an important energy source. In the production, transportation, storage, distribution, trade, and factory applications of natural gas, natural gas flow measurement is required.

With many years of experience in gas flow measurement services, Sino-Inst supplies commonly used natural gas flow meters. Including gas turbine flowmeters, thermal mass flowmeters, vortex flowmeters, etc. Accurate natural gas flow measurement improves operating costs in areas such as custody transfer, manufacturing, power generation and heating!

Read more about: Natural Gas Flow Meter Types and Guidelines;

And Techniques, Importance, and Challenges of Natural Gas Flow Measurement.

Ammonia is a commonly used gas, widely used in refrigeration, fertilizer, and other fields. During ammonia transportation and storage, its flow rate needs real-time monitoring and control. However, ammonia has a certain degree of toxicity and corrosiveness; therefore, the following factors need to be considered when selecting an ammonia flow meter:

  1. Flow Range: A suitable flow meter must be selected based on the actual flow range. A flow meter that is too large or too small will affect the measurement accuracy.
  2. Accuracy Requirements: Different application scenarios have different accuracy requirements for flow meters. Generally, high-precision applications such as refrigeration systems require flow meters with higher accuracy.
  3. Measurement Medium: Due to the corrosive nature of ammonia, a flow meter made of corrosion-resistant materials must be selected.
  4. Environmental Requirements: The environments in which ammonia is transported and stored are generally harsh, and the flow meter needs to be able to withstand high temperatures and high pressures.

Commonly used ammonia flow meters include vortex flow meters, turbine flow meters, thermal mass flow meters, and differential pressure flow meters.

Nitrogen flow meters are industrial digital flow meters used to measure the volumetric or mass flow of nitrogen. Nitrogen (N2) typically flows in either gaseous or liquid form. Here, we discuss the flow measurement and control of industrial gaseous and liquid nitrogen.

Installing a nitrogen flow meter and controller will improve your plant’s production efficiency. Nitrogen flow meters can measure and control instantaneous flow, totalized flow, and more. You can even use nitrogen flow meters to detect nitrogen leaks.

Read more about:

Compressed Air Flow Meter is a digital flow meter work for the air compressor. Thermal mass, vortex, portable ultrasonic, and DP flowmeters are commom gas flow sensors. Air consumption is an important info for industrial inline gas flow pipe.

Compressed air is the most expensive form of energy in manufacturing plants. And compressed air accounts for up to 20% of the overall energy costs. So, it is important to measure compressed air flows precisely in all conditions. This can improve the energy efficiency of compressed air systems while reducing costs. Sino-Inst offers compressed air flow meters with and without a local display. And 4-20mA and 0-10V outputs, and for hazardous area applications are available.

Read more about: Guide On Industrial Air Flow Measurement Devices

A CO2 flow meter is a device designed to measure the flow rate of carbon dioxide gas in a pipeline or process. CO2 flow meters are widely used in industries such as welding, medical gas delivery, greenhouse gas monitoring, and beverage production. Accurate CO2 flow measurement is crucial for process control, ensuring gas quality, and monitoring emissions.

Read more about: Types of CO2 Flow Meters

Hydrogen flow meters are widely used in hydrogen energy fields, such as hydrogen production, hydrogen storage and hydrogen fuel cells. Typically used to monitor volumetric flow, mass flow and usage of hydrogen to ensure proper system operation and optimize performance.

Since the value of hydrogen is very high, custody transfer metering is also a very important feature of hydrogen flow measurement.

Read more about: Featured Hydrogen Flow Meters

In its gaseous form, Propane has numerous applications. Propane is usually used for residential heating, cooking, and powering small appliances.

Industrially, propane can be separated from oilfield gas and cracking gas. It can be used as a raw material for the production of ethylene and propylene or as a solvent in the oil refining industry. However, to assure safe, efficient, and accurate usage, monitoring propane flow is critical. That’s where propane gas flow meters come into play.

Read more about: Choosing the Right Propane Gas Flow Meter

FAQ

The accuracy of gas flow meters is usually expressed as a percentage. Common accuracy classes include 1.0 and 0.5. Choosing the right flow meter requires considering the specific application scenario and measurement requirements.

The accuracy of a flow meter refers to the error between its measured result and the actual flow rate, usually expressed as a basic error. For example, a 1.0 class flow meter has an allowable error of ±1%.

The gas flow meters supplied by Sino-Inst have an accuracy of approximately ±1% to ±2.5%. The specific accuracy needs to be confirmed based on the flow meter type and measurement parameters.

After measuring gas flow, a gas flowmeter can display the data in real time on a digital display screen. Information such as instantaneous flow, cumulative flow, and flow velocity can be read directly, or the flow signal can be output to a monitoring room via 4-20mA, RS485, etc., for reading by a PLC or other system.

Flow meters used for natural gas flow measurement include: gas turbine flow meters, vortex flow meters, thermal mass flow meters, vortex flow meters, and orifice plate flow meters. We highly recommend gas turbine flow meters because they offer advantages such as high measurement accuracy, fast response, and good stability.

However, it’s important to note that turbine flow meters have certain requirements for the cleanliness of the gas being measured and are not suitable for low flow rates or conditions with large fluctuations.

First, you can check the flow rate on the flow meter’s digital display. If the flow meter reading is not displayed or far exceeds the normal range, the flow meter may be malfunctioning.

Second, you can use a multimeter to test:

  1. Electrode check: Use the multimeter’s resistance setting to measure the continuity of each electrode. Connect one probe to the electrode end and the other probe to the corresponding terminal in the junction box. If there is continuous continuity, there is no problem.
  2. Test the excitation coil with a multimeter: Use the multimeter’s resistance setting to measure the coil’s resistance. This value should not be infinitely large or close to continuity; a normal value should be between tens and hundreds of ohms (the resistance value may vary depending on the flow meter model).

In flow meters, 10D and 5D refer to the required straight pipe sections upstream and downstream of the flow meter. D is the pipe diameter (DN). For example, 10D upstream and 5D downstream means that a 10DN straight pipe section must be maintained upstream of the flow meter, and a 5DN straight pipe section must be maintained downstream. This ensures the stability of the fluid measured by the flow meter.

Different types of gas flow meters operate on different principles. For example, there’s the Annubar flow meter, which measures based on differential pressure, or the thermal mass flow meter, which measures based on thermal diffusion.

Further Reading:

The lifespan of a flow meter depends on its type and operating conditions. For example, under normal use, a flow meter can last 5-8 years. However, in corrosive environments or when measuring high-temperature media, the flow meter will experience significant wear and tear, thus shortening its lifespan.

Gas flow rate is a fluid parameter characterized by the volume of gas flowing through a detector or pipe cross-section per unit time. Common units are milliliters per minute (mL/min) or meters per second (m/s).

Q1, Q2, Q3, and Q4 are generally parameters in a water meter.

Q1: Minimum Flow Rate

Q2: Transition Flow Rate

Q3: Constant Flow Rate (Operating Flow Rate)

Q4: Overload Flow Rate

Most water meters have a minimum flow rate (Q1). Below this flow rate, accurate readings cannot be provided. It’s also important to ensure that the maximum flow rate through the meter never exceeds Q3. Meters that continuously operate within the overload flow rate range (Q4) have shorter lifespans and lower accuracy.

Choosing the right flow meter requires considering various factors. Based on Sino-Inst’s years of experience in flow measurement, we recommend considering the following factors:

  1. Measured medium: including viscosity, temperature, and corrosiveness.
  2. Pipe diameter and upstream/downstream straight pipe sections.
  3. Pipe pressure.
  4. Flow range: considering the maximum, commonly used, and minimum flow ranges.
  5. Signal output: requiring a mechanical local display or pulse, analog, or digital signal output?
  6. Material compatibility with the measured medium and industry standards.
  7. Whether the accuracy meets measurement requirements.
  8. Purchase cost, installation, and maintenance costs.
  9. Flow meter warranty period.

More Flow Measurement Solutions

Summery: Making an informed decision

Gas flow measurement is a key element of many industrial processes, ensuring operational skillfulness, safety, and cost management.

Sino-Inst is a Professional flow meter manufacturer and supplier from China. Sino-Inst offers over 50 flow meter products. Including differential pressure, thermal mass, Coriolis, ultrasonic, turbine, vortex, and rotameters. It’s primary to choose the right type for your circumstantial application.

One of the outstanding gas flow meter from Sino-Inst is SI-3201 GAS Turbine Flow Meter; it is the flange type turbine flow meter. It is a perfect choice for natural gas flow rate measurement.

If you need to purchase gas flow meters, or have related technical questions, please feel free to contact our sales engineers!

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