Liquid Nitrogen Flow Meter | Cryogenic LN₂

A liquid nitrogen flow meter measures LN₂ at about −196 °C, where the liquid sits close to its boiling point and any pressure drop can flash it to two-phase and wreck the reading. Instranova supplies cryogenic gear/PD, turbine and Coriolis meters for LN₂ from 10 L/h dispensing up to 21,600 kg/h custody service, with 4–20 mA, pulse or mass output. Pick by what you bill (volume or mass); specifications and a quote request are below.

Contents

• Why LN₂ flow is hard to measure
• Volume or mass? Pick first
• Technology selection
• Models & specifications
• Applications
• FAQ

Why LN₂ flow is hard to measure

LN₂ is a saturated liquid: it is always near its boiling point, so a small pressure drop across a meter can flash part of it to gas. That two-phase mix distorts a turbine rotor and makes a volume meter read high. Boil-off adds vapor to the line for the same reason. The fixes are mechanical and procedural: keep the liquid subcooled and the line full, size the meter to the real flow, and choose a technology that tolerates what your line actually does.

Cold also attacks the meter itself. Bearings and seals that work at ambient seize or drift at −196 °C, which is why a cryogenic flow meter uses cold-rated bearings, the right clearances and 316L wetted parts.

Volume or mass? Pick first

Decide this before the technology. If you transfer, fill or totalize, a volume meter (gear/PD or turbine) with a totalizer is simple and cheap. If you bill, batch or dose by mass, a Coriolis meter (a liquid nitrogen mass flow meter) reads mass and density directly and stays valid when density shifts, which volume meters cannot do.

Technology selection

Technology	Reads	Best LN₂ use	Watch out for
Gear / positive-displacement	Volume + totalize	Small-bore transfer, dispensing, fill records	Bearings in cold; size to low flow
Cryogenic turbine	Volume (pulse)	Clean subcooled liquid, high turndown	Single phase only; straight run; flashing reads high
Coriolis	Mass (+ density)	Billed or dosed-by-mass service	Cost; needs full pipe; size for low flow
Orifice + DP transmitter	Inferred volume	Rugged fixed lines where inline meters do not fit	Needs density comp.; small DP at high line pressure

Models & specifications

Real configurations we build for LN₂, all rated to −196 °C:

Model class	Type	Typical LN₂ range	Output / fit
GF06	Cryogenic gear / PD	10–500 L/h	4–20 mA, split display, G1/2, 24 VDC
GF15	Cryogenic gear / PD	Small-bore (~1/2″ line)	Pulse / totalize
DN6 turbine	Cryogenic turbine	100–600 L/h (2 bar)	4–20 mA, G3/8
DN50 Coriolis	Coriolis mass	to 21,600 kg/h, ±0.2%	Flow + total + density + temp
Orifice + DP	DP inferred	Fixed large-bore lines (e.g. 150 psig)	4–20 mA, needs density comp.

Two worked examples from recent projects: a US customer dispensing LN₂ took two GF06 gear meters (10–500 L/h, −196 °C, 22 psi, split display, 4–20 mA) for filling with totalized records, and an aerospace test facility in Canada uses a DN50 cryogenic Coriolis reading flow, total, density and temperature on LN₂ to 21,600 kg/h at ±0.2%. Same fluid, different service, different meter.

Applications

Typical uses:

• LN₂ dispensing and cylinder / dewar filling with totalized records
• Transfer from bulk storage to non-pressurized vessels
• Custody transfer and billing by mass (Coriolis)
• Aerospace and research test stands
• Food freezing, biobank and laboratory LN₂ supply
• Vaporised nitrogen / gas-phase metering (vortex or thermal mass)

For tank contents and pressure on the same system, see our cryogenic level sensors and cryogenic pressure transducers. The full selection logic is in the cryogenic measurement guide; the range sits under flow meters and gas & cryogenic.

FAQ

What does a flow meter do?

A flow meter measures how much fluid passes through a pipe, either the flow rate at an instant or the total over time, and sends it as a pulse, 4-20 mA, or digital signal. On a liquid nitrogen line that lets you batch a fill, bill by quantity, and watch for two-phase flow. The challenge with LN2 is the temperature near -196 C, so the meter and its bearings must be built for cryogenic service.

What is the most accurate flow meter?

It depends on what you are metering. For clean liquids a Coriolis meter is usually the most accurate, because it measures mass directly and is not fooled by changes in density or temperature, which matters when a cryogenic liquid sits near its boiling point. A well-built turbine meter is accurate and lower cost for steady single-phase flow. For liquid nitrogen, where some vapour can form, a mass-based Coriolis meter gives the most trustworthy total.

What are the two types of flow meters?

Broadly two: volumetric meters, which measure the volume passing (turbine, positive displacement, vortex), and mass meters, which measure mass directly (Coriolis, thermal). The difference matters for cryogenics: a volumetric meter reads a volume that shifts with temperature and any flashing to gas, while a mass meter reports the actual quantity delivered. That is why mass metering is preferred where the nitrogen is sold or dosed by weight.

About this article

Written and technically reviewed by Wu Peng, a senior process instrumentation engineer with 20+ years in industrial automation and measurement, last reviewed 2026-06-05 (AI-assisted drafting), based on cryogenic flow-metering practice and field experience supplying LN₂ gear, turbine and Coriolis meters from dispensing to custody service. Questions? Reach our application engineers.

Send the line size, flow range, operating pressure, output and whether you need volume or mass. Our application engineers reply with a sized meter and price.