What is gas flow meter ?
Gas flow meter
is a kind of gas flow measurement devices
that measure the flow of a gas. The gas
flow sensors are installed in the pipeline to display and record the amount of
gas passing through the pipelines. Gas flow meters can measure gas, air,
nitrogen, acetylene, phosgene, hydrogen, natural gas, nitrogen, LPG gas,
hydrogen peroxide, flue gas, methane, butane, chlorine, gas, biogas, CO2
, compressed air, argon Gas, toluene, benzene, xylene, hydrogen
sulfide, sulfur dioxide (SO2
), ammonia,propane gas flow meter
and so on.
No gas flow meter can fit any gas flow measurement
Well, if there would be a perfect flowmeter it will require no or little calibration, little maintenance, high turndown, reliable and high accuracy. The little costs and the purchase price will also be inexpensive.
Some suppliers argue that they have the perfect flowmeter but the fact is that chances of having one are minimal. This is because every typical flow meter has its disadvantages and advantages because of the principle of operation and the technology used.
The disadvantages that arise are because of material used in the construction, installation, and application. For instance, gas turbine flow meters would not operate effectively without the moving parts. On the other hand, Coriolis meters lack moving parts but technology requires them to be large which will make it expensive.
Additionally, magnetic flowmeters require conductive fluids when making measurements hence they can’t measure hydrocarbon liquids.
This article is set to explore the advantages and disadvantages of the latest flowmeters used to measure gas flow rate because liquids are easily measured compared to gas.
There are many gas flow meter types,the following are the common gas flow meters that Silver Automation Instruments often recommend to customers.
Thermal Mass flow meter for
Coriolis and Thermal Flow Meters measure mass flow through how thermal flow meters take measurements is quite different. They use heat conducting properties rather than fluid momentum which is used by Coriolis. Some thermal dispersion flow meter
can measure liquid flow although most of them measure gas flow.
Hotwire anemometers which contain heated thin wire were used in turbulence research and velocity profile. They are fragile and small hence they are susceptible to dirt and breakages that is why it is not recommended for industrial use.
Various technologies have been used for thermal Flowmeters. This is why some measures temperature difference between ambient flow stream and heated sensors. Others measure the speed of heat added to flow stream disperses. Therefore, Thermal Flow Meters require more than one temperature sensors so that it can measure the fluid temperature at integral points.
Just like the other Flowmeters, it has its advantages and disadvantages. Well, it is good for those who are under a tight budget because of the low purchase cost. Additionally, they can measure the flow of low-pressure gases that is what makes it more unique.
However, it offers low medium accuracy though there are improvements on this to make it more accurate.
-Well suited for emission monitoring applications
-Favorable for stack flow measurements
-It can measure the flow of low-pressure gas
-Insertion model can handle large pipes
-It can’t be used to measure steam flow
-It offers low to medium accuracy
-It is entirely used for gases just some few liquid applications
-The gas composition should be known
The thermal Mass flow meter is designed based on the principle of thermal diffusion. The flow sensor uses the constant temperature difference method to accurately measure the gas.It has the advantages of small size, high intelligence, convenient installation and accurate measurement. Thermal mass flow transmitter does not require external temperature and pressure compensation, and the measurement is convenient and accurate, the mass flow rate of the gas or a standard volume flow can be obtained. The wide range ratio of the thermal dispersion flowmeter measures gases with flow rates as high as 120 Nm/s down to 0.1 Nm/s and can be used for gas leak detection. The immersible mass flow meters has good seismic performance and long service life. The gas flow sensor has no moving parts and pressure sensing parts and is immune to the influence of vibration on the measurement accuracy. Factory automation and integration can be achieved by using RS-485 communication or HART communication. Digital thermal mass flow meter can be used for compressed air flow meters, propane gas flow meter,biogas flow meters, LPG flow meters, nitrogen flow meters, oxygen flow meters.
Gas turbine flowmeter
Gas turbine flowmeter
model is suitable for measuring various gases in various gas and industrial fields, such as natural gas, city gas, LPG, propane, butane, air, nitrogen, etc. The gas flow sensor has high accuracy and good repeatability, and is especially suitable for custody transfer. The gas turbine flowmeter is a kind of speed flowmeter with low pressure loss, high accuracy, low starting flow, large turndown ratio, good seismic and pulsation resistance. The gas flow instruments solled by Silver Automation Instruments is a digital gas flowmeter with electronic display of instant flow and total flow. It can output pulse or 4-20 mA, and can have RS485 communication to meet various industrial control needs of customers.
Coriolis Flowmeter for gas measurement
This is a fast-growing flowmeter which has
replaced differential pressure meters. Most people find it worth it despite its
They are used in measuring gas flow
although they work well with liquids than gases. The good thing is that it can
measure mass flow directly without using the formula for computation.
Advantages and disadvantages of Coriolis
meters for gas flow
-Approved for custody transfer
-Can handle sanitary application
Available in large line sizes up to 14
The following are its disadvantages:-
-Pressure drop for bent -tube meters.
-High initial cost
-Gas flow measurements can be difficult due
to the low density of gas
-It is expensive and unwieldy in line sizes
above four inches
Vortex shedding flow meter was introduced in the 1970s to the
industrial markets. Well, they can the principle of vortices when placed in a
downstream. They utilize the effect that was studied by Von Karman. A bluff
body which is broad and has flat front obstruction is inserted in the flow
stream. Therefore alternating vortices are generated due to the impact of the
bluff body in the fluid.
The frequency of vortices is directly
proportional to the velocity of flow. Vortex frequency is determined by
ultrasonic, thermal, pressure and several types of sensors. Therefore when you
multiply the velocity of flow and the area of the pipe you will get the
Vortex Flowmeters are advantageous because
of their versatility. They can tolerate high temperatures in steam flow and
measure the flow of steam, liquid, and gas.
These vortex meters have less pressure drop
than the DP Flowmeters. They also measure fluids with greater accuracy.
-Have no moving parts
-Use API standards
-Relatively high accuracy
-Has limited use for custody transfer
-The bluff body can cause a pressure drop
It is mainly used for flow measurement of industrial pipeline medium fluids, such as gases, liquids, vapors and other media. It is characterized by small pressure loss, large measuring range and high precision. It is almost unaffected by parameters such as fluid density, pressure, temperature and viscosity when measuring the volume flow rate. No moving mechanical parts, so the reliability is high and the maintenance is small. The flow instruments use a piezoelectric stress sensor with high reliability and can work in the operating temperature range of -20 ° C ~ +250 ° C. There are analog standard signals and digital pulse signal outputs, which are easy to use with digital systems such as computers. It is a relatively advanced and ideal flow meter.
Rotameter (Variable Area Flow meter)
The metal tube rotameter is a variable area flow meter based on float position measurement. It adopts all-metal structure, has the characteristics of small volume, small pressure loss, large range ratio (10~20:1), convenient installation and maintenance, etc. It is widely used in complex and harsh environments of various industries, for small flow, low flow rate. Silver Automation Instruments also sell digital rotameters with digital display to show instant flow and total flow, it can be made into rotameter with flow transmitters which can have alarm outputs, 4-20mA outputs, RS485 communication and so on.
Silver Automation Instruments supply gas flow meters with good quality and competitive price from China gas flow meters manufactures, welcome to contact us to send your gas flow measurement applications to us , we will always support you with best price and best service.