As an inert gas, nitrogen plays an irreplaceable role in numerous fields, including chemical synthesis, electronics manufacturing and laboratory analysis; the precise measurement of its flow rate directly impacts process stability, energy efficiency and the reliability of experimental data. As the core instrument for nitrogen flow measurement, nitrogen flow meters utilise diverse measurement principles such as differential pressure and thermal methods.By leveraging the low viscosity and inert properties of nitrogen, they achieve precise flow acquisition and quantification.
Nitrogen Flow Meters from Sino-Inst
For nitrogen gas in industrial pipelines, these four meters cover most jobs — from small N2 lines off a generator to large headers in a plant.
- Reads nitrogen mass flow and Nm³/h directly — no temperature or pressure compensation needed
- Inline sizes from DN10, e.g. DN25: 1.8–180 Nm³/h
- Accuracy ±1.5%; pressure ≤1.6 MPa (higher on request)
- 4–20 mA, RS-485 Modbus, pulse, HART; Ex d IIC T4
- Insertion design for nitrogen headers DN65 and larger
- Flow velocity 0.1–120 Nm/s; accuracy ±1–2.5%
- Sensor –40 to 100 °C or –40 to 220 °C; pressure ≤1.6 MPa
- 4–20 mA, pulse, RS-485, HART; integrated or remote converter
- Built-in temperature and pressure compensation for standard volume flow
- Flanged DN15–DN300; gas velocity 4–60 m/s, e.g. DN50: 36–320 m³/h
- Accuracy class 1.0 / 1.5; pressure 1.6, 2.5 or 4.0 MPa
- 4–20 mA, pulse, RS-485 Modbus; explosion-proof or intrinsically safe
- Automatic temperature, pressure and compressibility compensation
- DN15–DN200, e.g. DN50: 10–130 m³/h; accuracy 1.0–1.5%
- Pressure 1.6–6.3 MPa; medium temperature –20 to 80 °C
- 24 VDC or 3.6 V battery; 4–20 mA, pulse, RS-485, HART; Ex ia IIC T6
About Nitrogen
Nitrogen N2 is usually a colorless and odorless gas. Generally speaking, nitrogen is less dense than air. Nitrogen accounts for 78.08% (volume fraction) of the entire atmosphere and is one of the main components of air.
At standard atmospheric pressure, when nitrogen is cooled to -195.8°C, it becomes a colorless liquid. When cooled to -209.8°C, liquid nitrogen becomes a snow-like solid.
Nitrogen (N2) is an inert gas. It is widely used in a variety of industries, from food packaging to industrial processes, and is also used to blanket flammable materials. It is difficult to react with other substances at room temperature, so it is widely used to keep food fresh.
Nitrogen Gas
At atmospheric pressure (101.325 kPa) and room temperature, nitrogen is a gas. It is very stable and only reacts at high temperature, high pressure or with a catalyst, so it is widely used as a shielding gas and inert blanket. Nitrogen gas in a pipeline is clean, dry and non-corrosive, slightly lighter than air and barely soluble in water. Ordinary 304 or 316L stainless steel wetted parts are fine. For flow measurement, the point to watch is that nitrogen is compressible. Its density changes with pressure and temperature, so a vortex, swirl or DP meter needs temperature and pressure compensation to give Nm³/h or kg/h. A thermal mass meter reads mass flow directly and does not need it.
Liquid Nitrogen
Liquid nitrogen is made by compressing and cooling nitrogen gas. At atmospheric pressure it turns liquid at –195.8 °C. It is colourless and odourless, and cold enough to freeze material very quickly, so it is used for cryopreservation and freeze-drying. The liquid weighs about 0.808 kg per litre, and one litre becomes roughly 0.65 Nm³ of gas, close to 700 litres at room temperature. It boils off easily and takes in a lot of heat as it does, so liquid nitrogen is kept in vacuum-insulated tanks, and liquid lines are fitted with pressure relief. It needs cryogenic flow meters; see the liquid nitrogen section further down.
What is a Nitrogen Flow Meter?
In the field of industrial flow measurement, a nitrogen flow meter is an instrument specifically designed to measure and control the flow of nitrogen in various applications. It is often used in scenarios where accurate nitrogen delivery is critical, such as chemical blanketing or food packaging.
A nitrogen flow meter is an industrial digital flow meter used to measure the flow rate of nitrogen. Typically, nitrogen (N2) can flow in gaseous, liquid form.
If your plant requires nitrogen, installing a nitrogen flow meter will increase your productivity. Nitrogen flow meters can measure and control instantaneous flow, cumulative flow, and more. You can even use a nitrogen flow meter to detect if there is a nitrogen leak.
Benefits of Using a Flow Meter to Measure Nitrogen
Nitrogen flow meters have significant advantages. By preventing overcurrent or underwriting, security is provided, valuable data is provided, and key nitrogen flows are monitored to ensure smooth operation without interruption.
Save cost
Determine the areas of excessive consumption and implement measures to reduce waste
Process control
Make sure the product quality is consistent and prevent problems caused by air fluctuations.
Leakage detection
Monitoring flow rate helps to identify potential leakage in the nitrogen system, timely repair and prevent gas loss.
Enhance security
Prevent dangerous situations such as overpressure or sudden decline in pressure.
Data analysis
Analyze the nitrogen use mode in detail to determine the trend and optimize the operation of the system.
Inventory management
To better manage nitrogen inventory and prevent unnecessary excess inventory.
Types and Features of Nitrogen Flow Meters
Different types of nitrogen flowmeters use different technologies to measure flow, including vortex flowmeters, rotating vortex flowmeters, differential pressure flow meters, and thermal gas flowmeters.
Sino-Inst offers a variety of traffic meters for nitrogen. If you need any further help or information, please contact us.
Flow meters for nitrogen
Vortex Flow Meter
Vortex flow meter work is based on the principle of Kamen Vortex Street. Can be used for traffic measurement of various industrial gases, liquids and steam.
1. The measurement range is wide and the pressure loss is small.
2. There are diverse structures, including flanges installation, pairing installation, etc.;
3. High measurement accuracy.
4. Support integrated and split temperature pressure compensation;
5. The measurable media range is wide.
Precession Vortex Flowmeter
The Precession vortex flowmeter is a new type of gas flowmeter. The flow meter is a flow, temperature and pressure detection function, which can automatically compensate the temperature, pressure and compression coefficients.
1. Measure natural gas, compressed air and other gases
2. Automatic compensation temperature, pressure and compression factor
3. LCD display, the head can rotate at 360 °
4. 24V, 3.6V battery power supply
5. High reliability, high operating accuracy, wide range of flow
Differential Pressure Flow Meter
Differential flow meter is a measurement technology to measure liquid, steam, or gas flow in the pipeline in the pipeline.
1. Suitable for various fluids, including gas, liquid and steam;
2. Have high accuracy and reliability;
3. Simple design, no activity components, convenient manufacturing and installation.
4. Compared with other flowmeters, cost performance is high;
5. Adapting to high temperature and high -pressure environment, traffic can be measured under bad conditions.
Thermal Mass Flow Meter
Thermal mass flow meter is an instrument that measures gas flow with the principle of heat diffusion. Sino-Inst’s thermal gas quality flow meter has two types: plug-in and direct pipe segmentation type
1. No need for temperature and pressure compensation for gas flow measurement.
2. The range ratio is wide and can be used for gas leak detection.
3. Good shock resistance and long service life.
4. Convenient installation and maintenance.
5. Digital design.
6. Using RS-485 communication or Hart communication can achieve factory automation and integration.
7. Optional AC220V, DC24V or AC220V, DC24V dual power supply.
Flow meters for liquid nitrogen
Cryogenic Turbine Flow Meter
A cryogenic turbine flow meter is an instrument based on the principle of fluid momentum, specifically designed for measuring the flow of cryogenic media such as liquid nitrogen. It is available in two types: insertion-type and in-line-type.
1. Designed specifically for cryogenic conditions, it can operate in extreme low-temperature environments ranging from -200°C to ambient temperature;
2. High measurement accuracy and good repeatability, making it suitable for high-precision measurement of cryogenic media;
3. Compact structure with low fluid resistance, ensuring it does not affect the normal operation of cryogenic pipelines;
4. Equipped with cryogenic-resistant sealing components to prevent leakage of cryogenic media;
5. Stable output signals, supporting pulse, 4–20 mA analogue signals or digital communication;
6. Easy to install with minimal maintenance requirements, meeting the special installation demands of cryogenic pipelines.
Vortex Flow Meter
A vortex flow meter is a flow measurement instrument that utilises the Karman vortex street phenomenon generated when a fluid flows past a non-streamlined obstruction to measure the flow rate of gases, liquids and steam. It is available in three types: insertion, pipe-mounted and clamp-on.
1. Suitable for a wide range of fluids, including gases, liquids and steam, offering high versatility;
2. No moving parts, minimal wear, long service life, and stable, reliable operation;
3. Wide turndown ratio and broad measurement range, eliminating the need for frequent parameter adjustments;
4. Low pressure loss, excellent energy-saving performance, and reduced energy consumption in pipeline operations;
5. Simple installation, with the option of horizontal or vertical mounting to suit different pipeline layouts;
6. Supports HART and RS-485 communication, facilitating integration into factory automation systems.
Mass Flow Meters
A mass flow meter is an instrument that directly measures the mass flow rate of a fluid without the need for temperature or pressure compensation. The most commonly used type is the Coriolis mass flow meter, which is primarily available in two types: in-line and insertion.
1. Direct measurement of mass flow rate; measurement accuracy is unaffected by changes in fluid temperature, pressure or density;
2. Suitable for measuring the flow of liquids, gases and multiphase fluids;
3. Capable of simultaneously measuring multiple parameters such as flow rate, density and temperature, offering comprehensive functionality;
4. Fast response time, suitable for operating conditions with significant instantaneous flow fluctuations;
5. Wide measurement range, suitable for everything from minute to high flow rates;
6. Digital signal output with strong anti-interference capabilities, facilitating integration with control systems.
GF Gear Flow Meter
The GF gear flow meter is a positive displacement flow meter that calculates flow rate by measuring the volume of fluid displaced by rotating gears. It is specifically designed for high-precision measurement of high-viscosity fluids and is available in both industrial and food-grade versions.
1. Extremely high measurement accuracy with excellent repeatability, suitable for precision metering applications;
2. Suitable for high-viscosity fluids, whilst also capable of measuring standard liquids;
3. Robust construction, excellent sealing performance and high corrosion resistance, making it suitable for a wide range of harsh operating conditions;
4. No straight pipe run requirements; flexible installation, suitable for confined spaces;
5. Stable operation, low noise, long service life and low maintenance costs;
6. Supports multiple output signals, enabling seamless integration with PLC and DCS systems.
Nitrogen Flow Meter Applications & Case Studies
Where do our nitrogen flow meters actually go? Mostly here:
- Nitrogen generators (PSA or membrane), on the outlet, to see how much N2 the unit really makes. The gas is dry and clean, so a thermal mass meter is the usual pick.
- Sub-metering in a plant, one meter per workshop or production line. Inline thermal for small branches; for headers above DN65 we normally use the insertion type.
- Purging and inerting of reactors before and during a batch. Case 2 below is a typical one.
- Tank blanketing. Flow is small and steady, so what matters is how well the meter reads at the low end, not the top of the range.
- Ships and offshore units. Lines are often large; see Case 1.
- Industrial gas supply, where nitrogen from a bulk tank or vaporizer is metered to the user (Case 4).
- Food packaging, laser cutting and electronics plants, for flushing, assist gas and reflow ovens.
If you need a small flow indicator for nitrogen purging during HVAC brazing, that is a different product and not covered here.
Case Studies – Nitrogen Gas
Case 1: DN125 thermal mass flow meter for a marine and offshore supplier, Indonesia
Delivered; customer has reordered.
Nitrogen gas, DN125 flanged, 44–4,400 Nm³/h, 1.6 MPa, –40 to 100 °C. 4–20 mA output with dual power supply (AC220V / DC24V).
One thing we learned on this order: the PO said “1,800 m³/h” and did not say whether that was normal or actual volume. With nitrogen the difference is big, so we now ask every customer to state Nm³/h (0 °C, 1 atm) or m³/h at line conditions before we set the range.
Case 2: Nitrogen to batch reactors at a chemical plant, Pakistan
Solution quoted.
Each reactor takes 2–15 Nm³/h of nitrogen at 4–6 bar and 15–35 °C. The small reactors have ½” lines and the large ones 1″. We offered flanged thermal mass flow meters in DN15 and DN25, both ranged 2–15 Nm³/h, so the operators read every reactor on the same scale.
Case 3: Low-flow nitrogen for a public tender, India
Solution quoted.
Nitrogen at 25 °C, 0.75 kg/cm² working (1 kg/cm² max), normal flow 2–4 m³/h in a DN15 (½”) line, with a communication output. The buyer’s concern was that a meter ranged up to 60 m³/h would not be accurate down at 2–4 m³/h, which was a fair point. We changed the offer to a DN15 thermal mass flow meter ranged 1–10 Nm³/h. They also asked about argon, so we gave the converted range for argon as well: 1–8.8 Nm³/h.
Case 4: Ambient nitrogen line for an industrial gas company
Solution quoted.
DN50 line, nitrogen at ambient temperature, 5–6 bar working and 9 bar max. At the enquiry stage the customer could only estimate the flow. We quoted a DN50 thermal mass flow meter ranged 7–700 Nm³/h, which leaves room either side of their estimate.
Case Studies – Liquid Nitrogen
Vortex Flow Meter
DN15
Measured medium: Liquid nitrogen
Flow range: 560–4550 L/h
Pressure: 90 PSIG
Pressure rating: 1.6 MPa
Temperature: –174 °C
Signal output: 4–20 mA, LCD display
304 stainless steel flange connection
Accuracy: 1.5%
Cryogenic Vortex Flow Meter
For liquid nitrogen
DN10
Flow range: 0.2–1.2 m³/h
Pressure rating: 1.6 MPa
Temperature: –196 °C
24 VDC
Local digital display + 4–20 mA
Accuracy: 0.5%
More liquid nitrogen projects and meter options are in our guide to liquid nitrogen flow meters.
How to Choose the Best Nitrogen Flow Meter?
When picking the best nitrogen flow meter, there are a few things to think about: the conditions it’ll be used in (like flow range, temperature, and pressure), how accurate you need it to be, how much it’ll cost and how easy it is to maintain, if it’s suitable for the environment, if the materials it’ll be dealing with are compatible, and if it meets safety standards.
Whether you require a mass flow meter or a volumetric flow meter depends on your specific requirements for measuring nitrogen flow. If you need to obtain the actual mass flow rate of nitrogen directly and avoid the effects of temperature and pressure fluctuations, a mass flow meter should be your first choice. If you only require a reference for volumetric flow and do not have high accuracy requirements, a volumetric flow meter will suffice.
Operating conditions:
Determine the actual nitrogen flow range for the process (including minimum and maximum flow rates), operating temperature (ambient/low/high), and operating pressure (atmospheric/high). As nitrogen is highly compressible, fluctuations in temperature and pressure directly affect its density and flow rate. Ensure that the selected flow meter’s measurement range and temperature/pressure tolerance fully match the operating conditions; where necessary, incorporate temperature and pressure compensation functions.
Accuracy requirements:
In many applications, high-precision measurement is critical, particularly in scenarios such as trade settlement and blending control, where even minor measurement deviations can have significant economic implications or cause process fluctuations. The accuracy grade has to be decided based on what’s actually needed, so we don’t end up spending more than we need to on high accuracy, while making sure that if it’s not accurate enough, it doesn’t mess up the production or metering.
Cost and Maintenance Requirements:
There are big differences in the costs of buying and maintaining different types, brands, ranges and accuracy grades of nitrogen flow meters. You’ve got to think about the initial costs and the long-term running costs. Priority should be given to flow meters with simple structures, easy maintenance and convenient calibration to minimise downtime and associated costs during maintenance, thereby extending the instrument’s service life.
Environmental Considerations:
Verify that the instrument can withstand the anticipated operating temperature and pressure of the nitrogen, whilst being suitable for the on-site installation environment (e.g. pipeline vibration, dust, humidity, etc.). For example, if you’re dealing with pipeline vibration, go for a flow meter that can handle it and won’t be affected by interference. For low-temperature situations, pick materials and sensors that can handle the cold, and make sure the piping is well insulated.
Material compatibility:
Just make sure that the materials used for the flow meter components that come into contact with the medium are compatible with nitrogen. Also, think about any trace contaminants in the nitrogen, like oil mist, dust or moisture, to stop corrosion or contamination of the materials, which could mean that the instrument fails or the measurements aren’t accurate. For pure nitrogen, standard metallic materials can be used; for nitrogen containing impurities, choose a design that is resistant to contamination and has a non-restrictive flow path.
Safety and Compliance:
If you’re using high-pressure nitrogen or working in special environments like explosion-proof, flammable or explosive areas, it’s crucial that your instruments meet the relevant national safety standards and industry certifications. This makes sure the instrument can handle pressure and is explosion-proof, meeting all the necessary standards. This helps to prevent safety issues that might come from equipment failure and makes sure the production site stays safe.t
Exploring the world of nitrogen flow meters can seem complex, but with the right tools and knowledge, you can harness the power of nitrogen flow meters to drive your efforts to success.
Sino-Inst has many years of experience supplying flow meters. Based on standard flow meters, we customize flow meters with special parameters for many customers. For example, high temperature, high pressure, large diameter pipe insertion installation. Or, a small-diameter thread or clamp connection.
Please contact our engineers to customize your exclusive nitrogen flow meter!
FAQ
Not with our clamp-on meters. They are made for liquids, and the signal does not get through a gas-filled pipe well enough to measure. For nitrogen gas we use inline thermal mass or vortex meters. One customer wanted a non-contact meter on a 60–70 bar nitrogen test line in 1/4″ to 3/8″ tube; in the end a small DN15 inline mass flow meter was the practical answer.
A thermal mass meter is set up for the gas it will measure. We calibrate it on air and apply the nitrogen gas factor before shipping, and the calibration certificate comes with the meter, so no calibration is needed on site. If the same line also carries argon, oxygen or another gas, tell us, because each gas needs its own setting.
Inline. Our inline thermal meters are rated ±1.5%, insertion meters ±1–2.5%. On small and medium lines we use the inline type; we would not put an insertion meter in a DN25 line. Insertion makes sense on large headers, DN65 and up, where an inline body gets heavy and expensive.
Often not, so pick the range around the flow you actually run. In one tender the normal flow was 2–4 m³/h and the meter on offer went up to 60 m³/h; we changed it to 1–10 Nm³/h so the normal flow sat well inside the range. Also check whether the accuracy is stated as % of full scale or % of reading. On a 50 SLPM meter, 1% of full scale is ±0.5 SLPM, which is 2% of a 25 SLPM reading.
