Hydromechanical Horology: Inside the New HYT H1

HYT H1 PVD side

One of the most talked-about timepieces of the 2012 Baselworld watch fair was the HYT H1, an unusual-looking watch that indicates the time by means of two liquids — one green, one clear — that flow through a tiny tube along a peripheral hours scale. WatchTime technical editor Mike Disher explores the technology behind the watch and its movement, and we provide wallpaper images, prices, and an informative video.

Water clocks were the first complicated systems for measuring time. A millennium after they were invented, Confucius said that time flows away like the water in a river. The metaphor comparing flowing water to passing time is deeply ingrained in us. Lucien Vouillamoz recognized this, and in 2002 he proposed bringing the water clock into the 21st century and putting it on your wrist. Many ideas are more easily said than done, and this proved to be one of them.

Over the next several years, the concept evolved into a system in which a small, flexible reservoir, or bellows, would be attached to each end of a thin, clear, circular tube that would fit inside a watch case. The bellows and tube would contain two different liquids — one colored, one clear. Where the liquids met, a line, or meniscus, would be visible. As one bellows compressed, the meniscus would move, like fluid being pushed through a needle by a syringe plunger. Put an hour or minutes scale next to the circular tube, and the moving meniscus could mark the passage of time. That is the basic concept behind the HYT H1.

Click here to watch the HYT H1 video!

With the concept in place, Vouillamoz needed a working prototype and patent protection. He called on longtime friend and serial entrepreneur Patrick Berdoz, who invested in the project and played an important role in its success. Over the next year, the HYT company came into being, as did a working prototype. (The company name can be pronounced either “hit” or as the three letters “H-Y-T.”  Asked what the initials stand for, we were told either “hydro-technology” or “hydro-time.” The watch may be ready, but the finer points of the marketing effort are still being resolved.)

In 2010, Vincent Perriard joined HYT as CEO. Perriard is no stranger to extreme watchmaking. He was president of Concord when the brand developed the C1 Quantum Gravity, a huge, avant-garde watch that gained famed in horological circles for its unusual technological features.

To shepherd the project from prototype to production-ready timepiece, HYT recruited Bruno Moutarlier, the former industrial director for Audemars Piguet. Movement development was handled by Chronode — specialists in the design and construction of complex mechanical timekeepers. Its task was to create a traditional mechanical movement to handle the non-traditional task of pushing liquid through a tube.

Not surprisingly, realizing the project required solving several technical challenges. It also generated some new terminology. During our interview, phrases like “hydro-mechanical horology” and “fluidic-mechanical movement” popped up. It’s a good bet you won’t find these terms in Berner’s Dictionary. (Scroll down to see computer-generated sketches of HYT’s technology.)

HYT H1 computer sketch 1
The motion of the bellows pushes the green liquid through the tube.
HYT H1 computer sketch 2
The liquid follows the hour track along the periphery of the dial.
HYT H1 computer sketch 3
The meniscus of the colored liquid indicates the hour.
HYT H1 computer sketch 4
The tube is positioned just below the crystal for high visibility.


The company had to adopt technology and assembly techniques from the aerospace, chemical and medical industries. For example, the two liquids could not mix or change consistency, nor could they leak or evaporate. Preciflex, a sister company of HYT, worked on the fluid operation with the support of Helbling Technik, from the medical instrument world. The clear and green liquids are in fact oil, water, and some additional chemicals HYT will not disclose. Though the bright green liquid has a fluorescent quality, it does not glow in the dark… yet. HYT is working on that. If green liquid is not your cup of tea, so to speak, don’t worry — other colors will become available down the road.

HYT H1 Black DLC
The HYT H1 in black DLC case

HYT H1 Black DLC front

HYT H1 Black DLC back
The exhibition caseback reveals the movement’s bellows-and-pistons system.

To prevent leaks and evaporation, the system is manufactured to very close tolerances. The glass tube containing the liquid is blown by a machine to a tolerance of 1 micron. The material used to create the bellows was inspired by sensors used by NASA. The inner surface of the bellows is coated with gold to increase strength and flexibility. The liquid-handling system must be assembled in a clean room. Seven patents have been registered for the technology, and one for the design.

Continue to page 2 for more info and photos…

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