Hydrogen: Mastering pressures. Creating the future






13 Jul, 2023



Hydrogen: Mastering pressures. Creating the future

Jul 13, 2023

Looking towards the future for over sixty years

Over the decades, Comex has consistently pushed the boundaries of innovation to provide advanced technological solutions. Whether it’s on the technical side, creating high and low-pressure compatible systems, or on the physiological side, advancing our understanding of the impact of pressure variations on the human body, Comex has consistently created and experimented.

Today, we continue with this vision of the company. Therefore, we are pleased to announce that for several months, our company has been participating in developments in a promising market: hydrogen.

A heritage of expertise and innovation

Our commitment to hydrogen is not a fresh start for us but rather a natural evolution of our expertise. In fact, since its inception, Comex has positioned itself as a leading company in the development of breathing mixtures for divers and deep-sea workers, establishing a world record at -701 meters. These remarkable advancements were the result of the ambitious research program called “HYDRA.” These pioneering experiences took place over 18 years and allowed us to understand the unique properties of hydrogen and cultivate a solid knowledge base on this gas and its handling.

Innovating for the future of hydrogen

Today, hydrogen is emerging as one of the key fuels for our energy future. It offers new perspectives in areas such as transportation, energy storage systems, green electricity production, and much more. Our company is determined to contribute to this energy revolution with its expertise.

With six decades of experience, we are ready to tackle technical challenges and create innovative solutions. Our teams of experts are at the forefront of research and development, working on new technologies, special machinery, containment chambers, and various applications with controlled pressure. Our goal is to ensure the safety, efficiency, and reliability of hydrogen systems.

Partnerships for a sustainable future

The large-scale deployment of hydrogen for energy production can only be achieved by overcoming several technological barriers. Comex is determined to contribute its skills and knowledge to address these challenges, in partnership with other industrial players and research institutes. We work closely with our partners to jointly shape a sustainable and prosperous future.

Comex’s legacy in pressure mastery positions us ideally to tackle the challenges related to hydrogen and open new perspectives for this valuable resource. We take pride in using our expertise to contribute to the construction of a cleaner, more energy-efficient, and environmentally friendly world.

Looking back on the HYDRA adventure

From compressed air to hydrogen

Compressed air diving has its limits. Factors such as breathlessness, oxygen toxicity, and the effects of nitrogen narcosis force divers not to exceed a depth of 50/60 meters. This phenomenon, known as narcosis or “depth intoxication,” led the U.S. Navy to test a synthetic breathing mixture called “HELIOX” in the 1930s. This mixture replaces nitrogen with helium and reduces the amount of oxygen according to the depth, thereby improving performance by eliminating the effects of narcosis, breathlessness, and hyperoxia. New decompression tables were developed for this “cocktail.” However, it was quickly discovered that using HELIOX beyond 200 meters of depth posed new problems. Divers experienced dizziness, tremors, clumsiness in movements, sleep and appetite loss, which was described in 1968 by the Comex team as “High Pressure Nervous Syndrome” (HPNS).

To overcome this issue, Comex embarked on experiments with new breathing mixtures to allow divers to exceed 200 meters and work at even greater depths. This is how hydrogen was introduced into the breathing “cocktails,” creating “HYDROX” (a mixture of hydrogen and oxygen) and “HYDRELIOX” (a mixture of hydrogen, helium, and oxygen)! These mixtures significantly reduce the effects of High-Pressure Nervous Syndrome (HPNS) and greatly enhance the efficiency and working capacity of divers. Thanks to the use of these hydrogen-based breathing mixtures, professional divers have been able to work safely and effectively in the sea at depths of up to 530 meters.

HYDRA (1968-1992) :

The program focuses on the development of deep-sea diving under hydrogen-based breathing mixtures at very great depths (between 70 and 701 meters).

In 1968, during the long-duration experimental operation “PHYSALIE 1,” Henri-Germain Delauze and American researcher Ralph Brauer conducted submerged tests at a depth of 335 meters in the hyperbaric chamber “piscine” of the Hyperbaric Experimental Center. This experiment led neurophysiologists to make a major discovery: High-Pressure Nervous Syndrome (HPNS). The symptoms of this syndrome include tremors, nausea, poor coordination of movements, and abnormal results on the electroencephalogram.

It was then that Henri Germain Delauze launched and led the “HYDRA 1” operation, during which two divers attempted to breathe a hydrogen-based mixture called HYDROX (a mixture of hydrogen and oxygen) at a depth of 255 meters, in open water. However, the test was not successful as the diver’s equipment was insufficient to protect them from the cold. This was followed by “HYDRA 2” which conducted numerous experiments on various biological models, including cell cultures, bacteria, frogs, mice, and more. At this point, Henri Germain Delauze enforced the rule of “Bringing back the living.

It wasn’t until 1982 that the hydrogen research program “HYDRA” was relaunched, taking advantage of advancements in equipment. This was followed by a series of experiments from “HYDRA 3” to HYDRA 12, conducted from 1983 to 1996.

HYDRA 3 : COMEX198370/9116HYDROX

Comex tests numerous breathing mixtures such as:

  • NITROX” (a mixture of nitrogen and oxygen)
  • TRIMIX” (a mixture of helium, nitrogen, and oxygen)
  • HELIOX” (a mixture of helium and oxygen)
  • HYDROX” (a mixture of hydrogen and oxygen)
  • HYDRELIOX” (a mixture of hydrogen, helium, and oxygen)d’oxygène)

Highlights of the HYDRA program

HYDRA 3 : In 1983 Henri-Germain Delauze dives in the sea to a depth of 75 meters while breathing an “HYDROX” mixture, and then performs a second dive to 91 meters using the same breathing mixture. Fifteen other Comex divers will subsequently take turns in short-duration test dives at a depth of 75 meters under “HYDROX” from the surface. This proves that it is possible to live while breathing a hydrogen-based mixture.

HYDRA 5 : In 1985, Henri-Germain Delauze and Dr. Xavier Fructus supervised the experimental dive to a depth of 450 meters, which marked the world’s first instance of divers living, for 36 days, in saturation within a hydrogen-based gas environment.
HYDRA 8 : En 1988 en coopération avec la Marine Nationale, l’opération en mer “HYDRA 8” au cours de laquelle les plongeurs feront, en respirant un mélange hydrogéné “HYDRELIOX”, une démonstration de connexion de deux tronçons de pipeline par plus de 530 mètres de profondeur.

HYDRA 10 :In November 1992, Théo Mavrostomos took part in what would become the Record Dive to -701 meters. This dive in a hyperbaric chamber lasted for 43 days, including 13 days of compression and 23 days of decompression. Alongside two other divers, he entered the chamber and eventually achieved this world record alone, under the watchful eyes of the scientific teams. The diver shattered the depth record previously held by the Americans. It was a triumph for Comex, thanks to their HYDRELIOX mixture.

Thirty years later, this world record remains unmatched!


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