Choosing a proper flow meter for technical gases is essential to gain correct measurement data and information. It prevents making decisions on inaccurate data and it can save you a lot of money. VPInstruments offers flow meters for multiple inert industrial and technical gases, like nitrogen, CO2, oxygen, argon, helium, and special gas mixtures, which are used in packaging and welding applications. Make sure you answer the questions below to find the right gas flow meter for your application and situation.
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Process conditions, location, and purpose of your measurement all tie into the same base principle: it impacts the selection of the measurement principle. There are several technologies that you can use to measure mass flow of gases. Two technologies which are commonly used are thermal mass flow and differential pressure. Thermal mass flow meters possess a wide turndown ratio with which you can measure almost 100% of your consumption. Because of their large measurement range, you will detect even the smallest leakages of inert gases. So why not always choose a thermal mass flow meter? If the gas is polluted or wet, a thermal meter is not the best option. In that case it is better to choose a meter with a differential pressure flow sensor. A thermal mass flow meter measures dry air from 0.5 to 150 m/sec (0 to 500 sfps). A differential pressure meter 20 to 200 m/sec (65 to 650 sfps) and is therefore not suitable to measure leakages. The ratio between the high and low flow is called “turndown ratio”. So, for thermal mass flow meters this is typically 1:300, whilst for differential pressure flow meters the turndown ratio is 1:10.
There are two commonly used types of flow meters for measuring flow of inert gases: in-line and insertion type. Compared to the in-line meter, an insertion type flow meter has the benefit that it can be used for various pipe sizes, and it can be inserted under pressure when using a ball valve. Even an insertion point can be created under pressure by using a hot tap drill and hot tap saddle. However, there is a limit to the minimum pipe size for using an insertion type flow meter. Below 2” the field accuracy will be less due to the blockage effect: the sensor blocks a part of the pipe area, affecting the air velocity around the sensor. This effect increases significantly below 2 inch. In-line flow meters are more cost effective compared to insertion type flow meters, this applies for sizes up to 2”. In-line flow meters have a very high field accuracy, especially when using in- and outlet tubes of the supplier. There is one downside to the in-line meter. Unless the flow meter is installed in a special bypass, the process needs to be stopped (locally) when installing an in-line flow meter. This is also true when you want to recalibrate your flow meter.
For high accuracy, we strongly recommend selecting your flow meter that is calibrated with the specific technical gas. When low accuracy is required, a gas conversion factor can be used as this is more cost effective compared to a specific gas calibration. Be aware though that its accuracy can differ at different pressures and temperatures. In particular for helium, we strongly advise calibrating with real helium gas, at the system design pressure, as the conversion factor varies a lot over the pressure and temperature range. VPInstruments can calibrate your flow meter for CO2, nitrogen, helium, Corgon, argon and other industrial gases.
Local conditions can impact the reliability and the lifetime of the flow meter. For instance, vibration can cause your insertion flow meter to move slowly out of position (when not properly mounted). Direct sunlight can heat up the electronics too much where it will shut down. Long exposure to excessive temperatures may even cause permanent damage. Answer the following questions to describe these conditions and check the specifications of your flow meter consequently:
To get accurate measuring results, you also need to know the available straight pipe run and the preferred meter position. Straight run represents the pipe length without elbows, valves, and bends. The straight run requirements are based on laws of dynamic physics, and they are generally accepted as the standard. Depending on the pipe and upstream/downstream objects in the pipe, you will need an upstream of 20*D 1 till 40*D 1 upstream length and a 5*D 1 till 10*D 1 downstream length ( 1 =inner diameter). Read more about the piping tables. Please read this article to determine the required straight run for your flow meter.
There are roughly three ways to display the flow meter data: a local display right on the flow meter, displaying the data on a central building management system (BMS), and/or using a datalogger. All options come with their own requirements and their commercial impact. Especially when connecting your flow meter to a BMS or energy management system, proper investigation of the best turnkey solution can potentially save you a lot of money, time, and hassle.
Many flow meters are using an 4.20 mA output to readout their parameters. A proven and reliable solution, but often there is just one measurement parameter available on this output. VPInstruments’ offers 4-in-1 flow meters, measuring mass flow, pressure, temperature, and total flow simultaneously. In that case, a protocol like Modbus RTU is provided to read out all parameters at once. Using Modbus does require an expert to prevent costly mistakes during installation.
With industry 4.0, Ethernet is an upcoming standard. Ethernet has the benefit that it can potentially save you a lot of money on cables, when you can use the existing network infrastructure of the plant. Pricing of cables and their installation is often overseen, where it can be more expensive than the price of the flow meter all together.
The final thing you want to ensure is the paperwork. Do you need any certificates, documents, or tests? Also think of cleaning requirements. For example: for some oxygen applications, a special degreasing service is required for the flow meter. Always check what applies to your specific situation.
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How to choose the right flow meter? Flow meter types and their principles.
How to choose the right flow meter? To determine the perfect flowmeter, consider key criteria such as the fluid being measured, the flow range, the accuracy required and the process parameters. Our detailed guide will help you choose the most suitable flow meter to optimise your industrial processes and ensure accurate fluid measurement.
To determine the perfect flowmeter, consider essential criteria such as the fluid being measured, the flow range, the accuracy required and the process parameters.
Our detailed guide will help you choose the right flowmeter to optimize your industrial processes and ensure accurate fluid measurement.
In this article, we'll guide you through the process of choosing the right flowmeter for your specific needs.
Whether you are looking for a flowmeter to measure the flow of liquids, gases or steam, we will provide you with all the information you need to make an informed decision.
A flow meter is a measuring device used to determine the quantity of fluid flowing through a pipe. It is essential in many industrial processes, as it allows the flow of fluids to be monitored and controlled.
Now that we've defined the concept of a flowmeter, let's move on to the next question
The choice of flow meter depends on a number of factors, such as the type of fluid, the temperature and pressure conditions of the process, and the characteristics of the application.
Determine the type of flow meter required
Take into account specific parameters
Consider the Installation Requirements
Check out reputable brands
By following these tips, you'll be able to choose the flow meter that best suits your specific needs.
Now that we've covered the basics of choosing a flow meter, let's move on to a more detailed explanation.
Volume flow meters measure the flow rate in terms of the volume of fluid flowing through a pipe for a given period of time.
The differential pressure flow meter and primary element are suitable for measuring the flow of clean liquids and gases, or steam. It uses the differential pressure created by the fluid passing through an orifice such as an orifice plate or diaphragm.
Differential pressure is measured using pressure transmitters differential and converted into a flow rate.
The venturi tube flow meter is used to measure the flow of clean, charged and highly charged liquids, clean gases and charged gases.
It consists of a tapered section of pipe where the fluid velocity increases, enabling the flow rate to be measured as a function of the differential pressure between two measuring points.
The cone flow meter is designed to measure the flow of clean, loaded or highly loaded liquids. It consists of a widening pipe and a cone placed in the middle of the pipe.
The pressure difference between the inlet and outlet of the cone is measured to determine the flow rate.
The pitot tube flow meter is used to measure the flow of clean or slightly contaminated gases and liquids. It consists of a measuring tube placed parallel to the flow in the pipe. The pressure difference between the inlet and outlet of the tube is measured to determine the flow rate.
The main advantage of this type of device is that it does not obstruct the flow in the pipe, allowing higher velocity and greater efficiency to be maintained.
This type of flow meter is suitable for measuring the flow of clean, charged and viscous liquids, as well as clean gases. It uses a float whose position varies according to the flow rate, enabling the volume flowed to be measured.
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Gear flow meters are suitable for measuring the flow of clean, charged and viscous liquids, as well as clean gases. They use a pair of rotating gears to measure the volume of flowing fluid.
This type of electromagnetic flow meter is suitable for measuring the flow rate of clean, charged, viscous and conductive liquids.
The electromagnetic flow meter uses a magnetic field to induce an electromotive force proportional to the fluid's flow velocity, enabling the volume flow rate to be measured.
The vortex flow meter is suitable for measuring the flow of clean, charged liquids and clean gases. It uses vortices generated by the fluid flow to measure flow.
This type of non-intrusive flow meter is used to measure the flow of clean liquids.
It works on non-conductive fluids. It uses ultrasonic waves to measure the transit time of the fluid, enabling the flow rate to be calculated.
The latest generation of ultrasonic flowmeters can also measure saturated steam denit. These flowmeters are also available in a portable version. They enable uninterrupted flow measurement.
Mass flow meters measure the flow rate in terms of the mass of fluid flowing through a pipe over a given period of time. The most commonly used types of mass flow meters are:
The Coriolis flow meter is suitable for measuring the flow of clean, charged, highly charged, multiphase liquids, clean gases and charged gases. It measures flow by detecting the deflection resulting from Coriolis forces as a fluid flows through a vibrating tube.
Thermal mass flow meters are suitable for measuring the flow of clean liquids, clean gases and charged gases. They measure flow by detecting the heat transfer caused by the flow of the fluid.
In-line ultrasonic flow meters are used to measure gases such as air or nitrogen. They feature pressure and temperature correction to display the mass flow rate.
Now that you have an overview of the different types of flow meter and their principles, let's explore in more detail the parameters to consider when choosing a flow meter.
When choosing a flow meter, it is essential to consider a number of parameters to ensure that it is suitable for your specific application. Here are the main parameters to consider:
Type of fluid
Temperature and pressure conditions
Pressure losses
Need flow information
Installation features
By taking these parameters into account, you will be able to choose the flow meter that best meets your specific needs.
Here's everything you need to know to make the right choice of flow meter. Don't hesitate to consult reputable brands and seek professional advice if necessary. The right flow meter will ensure accurate and reliable flow measurement in your application.
There are several well-known brands in the flow meter field. Popular brands include Fuji Electric, Endress+Hauser, Yokogawa, Emerson, Siemens, Krohne, and ABB.
There is no single answer to this question, as the choice of flow meter depends on the specific application. However, electromagnetic, ultrasonic and coriolis flow meters are widely used in many industries because of their versatility and accuracy.
The flow rate in a pipe can be measured using an appropriate flow meter. The flow meter is installed in the pipe and measures the flow rate of the fluid passing through it using different measurement technologies.
The ideal conditions for measuring flow depend on the type of flow meter used. However, in general, stable temperature and pressure conditions, regular pipework without excessive disturbance and a clean fluid are conducive to accurate flow measurement.
Flow measurement is essential in industrial processes because it enables the flow of fluids to be controlled and monitored. This ensures that processes run efficiently and enables problems or undesirable variations in flow to be detected quickly.
Mass flow meters measure flow in terms of the mass of fluid flowing through them, making them independent of variations in fluid density. This makes them particularly suitable for applications where fluid density can vary.
We hope this article has provided you with the information you need to understand the different types of flow meter and their principles, thus to choose the right flow meter for your application.
The flow meter is an essential tool for measuring and controlling fluid flow rates in various industrial applications. Thanks to its advanced features, it ensures accurate measurement and optimal management of your processes.
Our experts will advise you on choosing the right flow meter for your needs.
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