Case study · Extreme environment simulation systems

Isolating an instrument from extreme environments: A custom flow meter for 6,000 m deep-sea sampling

For a major oceanographic research institute, IRIAN Mecatronics designed and built a custom flow meter to operate at a depth of 6,000 meters. The equipment shields a standard non-intrusive sensor from external pressure (625 bar) and corrosion, ensuring the scientific validity of seawater samples.

Client: Major oceanographic research institute
Field: Oceanographic research
Technique: Non-intrusive volumetric flow measurement

01 — The research question

How do you measure flow accurately when the instrument cannot survive the environment?

Some environments are so extreme—very high pressure, corrosion, radiation, explosive atmospheres—that no standard sensor can operate in them reliably. The solution is not to search for a perfect sensor that does not exist, but to isolate a proven measurement instrument from the specific stress it cannot handle, without altering the measurement itself.

This was the challenge for this project: to measure the volume of water pumped by a sampling tool at a depth of 6,000 meters. No off-the-shelf flow meter could withstand the 625 bar external pressure and corrosive seawater, let alone guarantee a non-contact measurement to avoid contaminating the scientific sample. The task required designing a custom system capable of creating acceptable conditions for the sensor in the heart of an extreme environment.

Achieve an accurate flow measurement with a sensor that can withstand neither the external pressure nor the corrosive environment, without disturbing the measured fluid.

02 — Our approach

The approach: Isolate rather than harden

The design is based on a core principle: placing the flow sensor, chosen for its accuracy and non-intrusive nature, inside a containment vessel that completely protects it from the deep-sea environment. Every component was selected to ensure the system's integrity and the reliability of the measurement.

Protecting the sensor from pressure and corrosion

The flow sensor and its electronics were not designed for 625 bar of external pressure. Rather than searching for a non-existent hardened sensor, we housed it in a sealed enclosure maintained at atmospheric pressure. This approach allows the use of a standard, proven instrument, fully protected from crushing forces and seawater.
Ensuring a non-contact, contamination-free measurement

To preserve the scientific integrity of the sample, all intrusive measurement methods (such as turbines or electrodes) were ruled out. We selected a non-intrusive technology, where the sensor measures through the pipe wall, which guarantees zero contamination, no internal corrosion, and no pressure drop that could affect the sampling process.
Transmitting signals from extreme depths

The electrical power and measurement signal had to pass through the enclosure wall without compromising its seal. We integrated specific bulkhead connectors, qualified for very high-pressure subsea environments, to ensure a reliable connection and protect the electronics from any water ingress.

03 — Beyond this project

Does your project face a similar constraint?

Nuclear

The constraint is measuring a parameter in a radioactive or corrosive fluid. The principle of a vessel isolating a standard sensor from the process fluid remains identical, adapting materials and certifications for radiation resistance and decontamination.

Chemical / Pharmaceutical (ATEX zones)

The challenge is using a high-performance analyzer that is not certified for an explosive atmosphere. The containment principle is transferable using an ATEX-certified enclosure, chemically compatible materials, and suitable connectors.

Deep geothermal / oil & gas

The need is to protect sensitive instrumentation from downhole conditions (HPHT, H2S). The HP containment vessel is still the solution, but it must be designed for extreme temperatures and with specific materials (Inconel, Hastelloy), a core expertise in our equipment for geosciences.

04 — Specifications

The values for this project. Every system is custom-built, so they adapt to your requirements.

Show specifications · 6,000 m · 625 bar (9,065 psi) · 630 bar (9,137 psi)

Technical specifications — Isolating an instrument from extreme environments: A custom flow meter for 6,000 m deep-sea sampling
Maximum operating depth	6,000 m
Operating external pressure	625 bar (9,065 psi)
Design external pressure	630 bar (9,137 psi)
Measurement principle	Non-intrusive
Output signal	4-20mA
Power supply	24V/DC

IRIAN Mecatronics designs and builds custom high-pressure, high-temperature equipment for research laboratories, technical centres and industry.

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05 — FAQ

Frequently asked questions

Can this enclosed flow meter principle be used for cryogenic or very high-temperature fluids?

Yes, the principle of isolating the sensor is adaptable. For cryogenic or very hot fluids, the design of the enclosure and process piping would include thermal insulation to keep the sensor within its nominal operating range. Materials would be selected for their resistance to extreme temperatures and thermal shock, in line with our expertise in extreme environment simulation.

Is this protection system applicable to other types of sensors besides flow meters?

Absolutely. This approach is designed for any standard measurement instrument (viscometer, gas analyzer, pressure sensor, pH meter, etc.) that must operate in an environment for which it is not rated. We design the enclosure on a custom basis around the chosen instrument, integrating all necessary fluid, electrical, and optical feedthroughs.

How is regulatory compliance (PED, ATEX) managed for such a custom enclosure?

The enclosure is designed and manufactured as a pressure vessel in its own right. Depending on the pressure, fluid, and volume, it is subject to the Pressure Equipment Directive (PED 2014/68/EU) and may require certification by a notified body. For hazardous areas, the design follows ATEX directives, as with our test benches for flammable gases.

What are the size and weight limitations for this type of protected flow meter?

There is no standard limit; the footprint depends on the size of the sensor to be protected and the integration constraints of your facility. Our engineering team (mechanical, instrumentation) works from your specifications to optimize the geometry and weight, selecting appropriate materials such as steels, titanium, or aluminum alloys.

Need to integrate a measurement instrument in an environment that exceeds its specifications?

Describe your pressure, temperature, corrosion, or regulatory constraints. Our engineering team will analyze your project's feasibility and propose a custom solution.

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