Natural gas flow meter types?
Why need natural gas flow measurement in industry?
Natural gas refers to a combustible gas mixture with hydrocarbons as the main component extracted from nature. Natural gas is mainly composed of a mixture of gaseous low-molecular hydrocarbons and non-hydrocarbon gases. It is mainly composed of methane (85%) and a small amount of ethane (9%), propane (3%), nitrogen (2%) and butane (1%). Mainly used as fuel, but also used to produce raw materials for chemicals such as acetaldehyde, acetylene, ammonia, carbon black, ethanol, formaldehyde, hydrocarbon fuels, hydrogenated oil, methanol, nitric acid, synthesis gas and vinyl chloride. Natural gas is compressed into liquid for storage and transportation. We need natural gas flow metering device in coal mining, nitric acid plants, power plants, organic chemical synthesis plants, petroleum refining plants, etc.
Always remember that to get an accurate measurement, having the correct technology is critical. Here are the things you should consider when choosing a flowmeter for natural gas. Industrial Natural gas flow meter can be used in monitoring incoming gas to a gas burner,boiler,ovens, furnaces.,etc
How to choose natural gas flow meters ?
It is essential to understand the application of flowmeter technology before you choose one natural gas flow measurement device. Recently we posted some tips to keep in mind when picking the correct gas flow meter. Understanding is central to making the right decision.
#1 What purpose will it serve? Are you picking meters for submetering, industrial gas processing, custody transfer, or monitoring? Is it a volumetric natural gas flow meter or mass flow meter you need? How much cost you will spend on the natural gas flow meter? Do you need inline natural gas flow meter?Or insertion natural gas flow meter?
#2 What type of gas is it measuring? Is it a mixture of gases or a single gas? What is the flow range, process temperature, accuracy required, and pressure? Will the gas be clean and dry. Or dirty, corrosive, and wet.
#3 Where is the intended installation? What conditions is it going to work under? Extreme temperatures? Will it have enough straight run? What regulations must it meet, if any? Are vibrations or noise a concern?
#4 What do you need it to do? Do you need a local or gas flow totalizer display? What calibrations do you need? Will advance electronics or upgrades be required? Do you need natural gas flow meter totalizer? Will you need it maintained? Do you need digital natural gas flow meter ?
Once you have gathered all this information, you can now make a more educated decision when choosing the correct gas flow sensor.
Refer to page two to recap the four types of natural gas meters that exist
&#; Volumetric flow
&#; Velocity meters
&#; Inferential flowmeters
&#; Mass flow meters for natural gas measurement
Natural gas flow meter types
Following your review of the selection guide, it is likely that you have narrowed the field to a few meters that might suit your purpose. Now you should list the advantages and disadvantages of each to make a more educated decision based on their operating principles.
&#; Thermal Mass Flow Meters: These meters rely on the principle that the rate of heat transfer is proportional to the mass flow rate of gas. They consist of a heated element and one or more temperature sensors. By measuring the temperature difference between the heated element and the gas, the flow rate can be determined. Thermal mass flow meter to measure natural gas has below flow units: SCFM, kg/h,g/s,g/min,NL/h, mmscfd, Sm3/h,Nm3/h, it has insertion type natural gas flow meter and inline type natural gas flow meters. The flow meter price can be very low for large natural gas pipeline.
&#; Coriolis Flow Meters: Coriolis flow meters utilize the Coriolis effect, which is the deflection of moving fluid due to the rotation of the Earth. These meters have a vibrating tube through which the gas flows. The gas motion causes the tube to twist, and the degree of twisting is proportional to the mass flow rate.Coriolis flow meter is the best natural gas flow meter, it can directly measure natural gas mass flow , and has the best accuracy for natural gas flow measurement.it can also measure high pressure natural gas flow rate.
&#; Turbine Flow Meters: These meters utilize a turbine rotor placed in the gas stream. As the gas flows through the meter, it causes the rotor to spin, and the rate of rotation is proportional to the flow rate. This rotational motion is converted into an electrical signal, which is then used to calculate the flow rate.
&#; Vortex Shedding Flow Meters: Vortex flow meters operate based on the principle that when gas flows past an obstacle (such as a bluff body), vortices or swirling patterns are shed alternately on each side of the obstacle. These vortices are detected and counted, and the frequency of vortex shedding is used to determine the flow rate.
&#; Orifice Plate Flow Meters: An orifice plate is a thin plate with a hole (or orifice) in the center. When gas flows through the orifice, it creates a pressure drop, which can be correlated to the flow rate. This pressure drop is measured using pressure sensors located before and after the orifice plate.
Industry Natural gas flow meter technical specifications
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Many natural gas flow sensor available: 3/4 inch, 1/2&#;, 1&#;, 2&#;, 3&#;, 4&#;, NB 100mm, 6 inch, 8 inch, 10&#;, 12&#; and max mm.
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Different process connection, wafer or flange, thread, inline natural gas turbine flow meter, insertion natural gas flow meter.,etc
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Pressure Rating: can be at low pressure rating such as 10 PSI, can be used to detect natural gas leakage, and measure low flow rate of natural gas, also has high pressure rating, such as 150LB, 300LB, 600LB ,900 class high pressure natural gas flow meter
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Output: 4-20mA output, pulse output, relay output for alarm purpose, real time data transmition, RS485 or HART Based natural gas turbine flow meter
Industry natural gas flow meter price
The price of industrial natural gas flow meters is determined by many factors. Customers can choose the right industrial natural gas flow meter according to their field application and budget. Our price for natural gas flow meter starts from $ 500. Send to us
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Natural gas flowmeter size: Generally, the larger the gas sensor size, the higher the price. For example, the price of a 4" natural gas flowmeter cost more than 1" natural gas flowmeter.
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Natural gas flowmeter measurement principle: different measurement principles, different prices. We can provide DP flow meters (differential pressure flow meter ), V cone flow meters for natural gas, orifice flow meters, Coriolis mass flow meters, thermal gas flow meters to measure natural gas, and turbine flow meters to measure natural gas volumetric flow rate. Pity is that SILVER does not sell natural gas flow meter ultrasonic principle or portable natural gas flow meter.
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Compressed natural gas pressure rating: We sell natural gas flowmeters at 232 PSI (normal condition). If customers need natural gas flowmeters with 600LB or 300 Class, ANSI or ASME pressure, the price will be not cheap. You can buy low flow natural gas flow meter from us , for NG gas with typical low flow just to detect leak from piping system.
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Natural gas flowmeter functions: electronic natural gas flow meter, natural gas flow meter totalizer calculation, HART communication, RS 485, lithium battery power supply, EVC (temperature and pressure correction )function.,etc , these functions will affect the price of natural gas flowmeter.
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Natural gas flowmeter brand: The natural gas flowmeter of well-known is not cheap, such as EMERSON, ROSEMOUNT, ENDRESS, FOXTHERMAL, SIERRA. But SILVER has many cheap alternatives for customers, you can buy economical natural gas flow meter from China factory .
Best flow meter for natural gas ?
We all hope to buy the best natural gas flow meters at low prices. The best natural gas lies in the working conditions and applications that the industrial natural gas flowmeter you choose to meet, the budget to be met, the prompt delivery date, and timely after-sales service. Find a good industrial natural gas flow meter manufacture is the best solution.
Gas turbine flow meter
Thermal mass flow meter
Vortex flow meter
The price of industrial natural gas flow meters is determined by many factors. Customers can choose the right industrial natural gas flow meter according to their field application and budget. Our price for natural gas flow meter starts from $ 500. Send to us to obtain your industrial natural gas flow meter price cost.We all hope to buy the best natural gas flow meters at low prices. The best natural gas lies in the working conditions and applications that the industrial natural gas flowmeter you choose to meet, the budget to be met, the prompt delivery date, and timely after-sales service. Find a good industrial natural gas flow meter manufacture is the best solution.
Comparing Gas Flow Instrument Technologies
Types of gas flow instruments
There are many ways to measure and control flow. Here we compare common mass and volumetric flow technologies, including Coriolis, laminar differential pressure, thermal, ultrasonic, rotameters, optical, and venturi.
Laminar differential pressure mass flow instruments
Laminar differential pressure-based (laminar DP) mass flow meters and controllers use the pressure drop created within a laminar flow element (LFE) to measure the mass flow rate of a fluid. To do this, an LFE converts turbulent flow into laminar flow by separating it into an array of thin, parallel channels. The pressure drop across the channel is then measured using a differential pressure sensor.
Because the flow within the channel is in a laminar state, the Poiseuille equation can be used to relate the pressure drop to the volumetric flow rate. The volumetric flow rate can then be converted to a highly accurate, standardized mass flow rate using temperature and pressure dependent density correction factors.
Use cases
Laminar DP flow devices require no warm-up time and are highly accurate due to the precise geometries in their construction. However, any clogging or condensation on the materials will change the geometry and therefore affect the system accuracy. These devices should therefore not be used to flow condensing or dirty gases.
Laminar flow measurement also depends on accurate data for how a gas reacts with varying pressure and temperature, which means knowing the exact gas composition is required for accurate measurement.
Best for
Clean, dry gases
Operating temperature and pressure within sensor limits
Avoid for
Condensing or dirty gases
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Unknown gas compositions
High viscosity gases
Coriolis mass flow instruments
Coriolis mass flow meters and controllers use the Coriolis effect to measure the true mass flow rate of a fluid. The fluid travels through a tube (or set of tubes) which is electromagnetically actuated. As fluid passes through, the moving tube experiences very tiny deflections from its initial vibration pattern.
Sensors measure the magnitude of this deflection, which is entirely dependent on the mass of the fluid. This allows for precise, true mass flow measurements by Coriolis instruments.
Use cases
Coriolis devices provide reliable, high accuracy mass flow measurements even for gases with changing densities. This makes them ideal for applications where gas composition is changing or has unknown physical properties. Because they can be constructed from various materials, Coriolis flow instruments can be also used for sanitary applications and with corrosive, dirty, or aggressive gases.
While Coriolis flow devices tend to have a higher cost of purchase, they require very little maintenance and have lower lifetime costs of ownership than many other flow meters. Some Coriolis devices can even measure multi-phase fluids like slurries, although this is typically only available in higher flow models.
The main drawback of a Coriolis is sensitivity to external vibrations.
Best for
Unknown compositions and/or physical properties
Sanitary applications
Corrosive or aggressive gases
Avoid for
Multi-phase fluids
Applications with vibrational noise
Thermal flow instruments
As the name implies, thermal flow meters and controllers use heat to measure the flow rate of a fluid. Thermal technology traditionally work in one of two ways. The first type measures the current required to maintain a fixed temperature across a heated element. As the fluid flows, particles contact the element and dissipate or carry away heat.
As the flow rate increases, more current is required to keep the element at a fixed temperature. This current requirement is proportional to the mass flow rate.
The second thermal method involves measuring the temperature at two points on either side of an element or &#;hot wire&#;. As the fluid flows over the element it carries the heat downstream, increasing the temperature of the downstream temperature sensor and reducing the temperature of the upstream sensor. The change in temperature is related to the fluid&#;s mass flow rate.
Use cases
Thermal flow instruments are calibrated to specific gas properties, and to maintain accuracy are therefore used primarily for pure gases, as well as gases with non-changing, known compositions. The biggest advantage of thermal flow devices is that they can be inserted into large pipes to measure in-line flows of known gases. They can also withstand higher pressures, at the expense of creating a large pressure drop.
Aggressive and coating gases may damage the sensor or necessitate frequent maintenance, especially if contaminated with water.
Best for
Gases of known compositions
High pressure
Insertion into pipes
Avoid for
Unknown gas compositions
Aggressive gases
Ultrasonic flow meters
Ultrasonic flow meters use sound waves to measure the flow rate of a fluid. Doppler flow meters transmit ultrasonic sound waves into the fluid. These waves are reflected off particles and bubbles in the fluid. The frequency change between the transmitted wave and the received wave can be used to measure the velocity of the fluid flow. Time of Flight flow meters use the frequency change between transmitted and received sound waves to calculate the velocity of a flow.
Ultrasonic flow meters can be an excellent option if you need to measure flow, but can&#;t install an invasive, new fixture to your flow path; some meters&#; transducers can be strapped or clamped directly to the exterior of a pipe!
The two methods used by ultrasonic flow meters are Doppler and transit time. Both types of meters emit an ultrasonic beam into the fluid medium. Doppler meters measure the change in frequency of the beam caused by the Doppler effect, and use the known speed of sound of the fluid to determine flow. Transit time flow meters emit two beams which reflect back into receiving transducers in the meter. The transmit times of the two beams can be used to find both the average fluid velocity and the speed of sound of the fluid.
Use cases
Ultrasonic flow meters are accurate, repeatable, and function well at extreme pressures and temperatures. Their unique advantage is that they can simply be clamped onto a pipe and offer non-invasive flow measurements. The meter therefore has no wetted parts and can be used when the pipes cannot be interfered with &#; although this does lower measurement accuracy.
Furthermore since ultrasonic flow meters do not actually contact the flows, they can be used for sanitary, corrosive, or aggressive gases. And unlike most of the other meters discussed here, these meters can accurately flow gases with bubbles and eddies.
The primary limitation of these meters is that they can only flow gases that conduct ultrasonic waves. They are also particularly sensitive to process vibrations and they lose accuracy as the pipe diameter changes, such as when buildup accumulates on pipe walls.
Best for
Mixed phase fluids
Non-invasive flow measurement
Avoid for
Gases that do not conduct ultrasonic waves
Applications with vibrational noise
Rotameters
Rotameters, also known as variable area flow meters, use a tube and float to measure volumetric flow rate.
As the fluid flows through the tube, the float rises. Equilibrium will be reached when pressure and the buoyancy of the float counterbalance gravity. The float&#;s height in the tube is then used to reference a flow rate on a calibrated measurement reference.
Use cases
Rotameters are the lowest-cost gas flow meters on the market, and can be used with a wide variety of gases, including those that may not be clean enough to flow through laminar DP flow meters.
Rotameters come with three primary drawbacks. As they are dependent on gravity, rotameters must be installed vertically and cannot handle upward flows; gas that is visibly dirty, opaque, or coats the glass of the meter can make it difficult to measure the flow visually; and rotameters can only be calibrated to read volumetric flow rate or a mass flow rate at a specific pressure, limiting the pressure range of a device.
Best for
Low-cost
Near atmospheric pressure
Avoid for
Applications with varying pressure
Gases that are dirty, opaque, or coat glass
Optical flow meters
Optical flow meters are used for fluids containing small solid particles that would likely clog devices relying on capillary bypasses or other restrictions to flow. They are also used to measure gas with liquid droplets, or liquid with bubbles.
Optical flow meters work by shining a laser perpendicular to the flow stream, so it collides with a particle. The light scattered by the particle is picked up by a photodetector, which generates an electric pulse signal. A second laser positioned further downstream of the first laser repeats this process with a second photodetector, and the velocity of the flowing gas is calculated as the distance the particle travelled over time.
Venturi flow meters
Venturi devices have the advantage of being very low cost, but at the expense of flexibility. The Venturi effect is a reduction in pressure caused by a constriction in a fluid&#;s flow path.
Pressure sensors measure the pressure before and inside the length of constriction, and the meter calculates fluid velocity using Bernoulli&#;s Equation. Bernoulli&#;s principle states that the speed of a fluid is inversely proportional to its pressure. This means decreasing the pressure of the gas with a known constriction and measuring the differential pressure yields a volumetric flow rate.
Contact an applications engineer about flow control solutions
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