Functional reliability and freedom from fogging

Ar-Dehumidifying Technology solves a basic problem of mechanical watches: the ageing of oils due to moisture in the air contained inside, or diffusing into, the watch. The movement is mounted in a nearly anhydrous atmosphere thanks to the three Ar-Dehumidifying Technology elements: drying capsule, EDR seals and protective gas filling. Ageing processes and fogging of the crystal from sudden cold are prevented, and reliable functioning and accuracy are ensured.

Inspection glass of the drying capsule of the U2 series at 6 o’clock.

Why does a waterproof watch need dehumidifying technology anyway?

The beauty and fascination of owning a SINN watch are enhanced by the knowledge of the fine mechanical precision of this object of daily use. Nonetheless, no matter how accurately the individual components are made, friction and wear must be minimised so that they function durably. Thus high-quality synthetic oils are used to ensure optimal lubrication of the movement bearings. This remains an unavoidable process in all mechanical watches. Humidity, however, accelerates the ageing of the oils.

How does moisture get into the watch?

Water is always present in the atmosphere in gaseous form, which is why it can penetrate the seal systems of a watch case. Temperature changes then cause micro-condensation, permitting water to collect in liquid form on exposed parts of the movement. The consequence: the efficiency of the lubrication deteriorates. Electrochemical corrosion, wear and friction increase, reducing the amplitude of the balance. The watch runs with decreasing accuracy and must finally be reconditioned. Our engineers looked for solutions to this problem and found them in the form of Ar-Dehumidifying Technology.

Mounted in a nearly anhydrous environment

These painstaking and technically elaborate measures are intended to keep the movement in a protective environment which is almost completely dry (anhydrous). A positive consequence of this is that it slows the ageing process of the oil, thereby extending the functional life of the movement. Also, fogging of the crystal due to sudden temperature shocks (such as immersion in cold water) can be prevented, ensuring that the watch remains clearly legible at all times.

Three-year warranty

Ar-Dehumidifying Technology is a truly pioneering achievement for mechanical wristwatches by our engineers – and a decisive advancement for all aficionados of mechanical watches. A three-year warranty is offered on all watches featuring Ar-Dehumidifying Technology.

Three technical elements

The Ar-Dehumidifying Technology works with three technical elements: drying capsule, EDR seals and protective gas filling. The drying capsules consist of five components which are pieced together in our Frankfurt workshop and then individually tested one by one.

1. The primary element: the drying capsule

The drying capsule is the most important part of the Ar-Dehumidifying Technology. The capsule is filled with copper sulphate; this absorbs moisture from the air inside the case and binds it permanently. Copper sulphate turns increasingly blue as its water content rises; the shade serves as an indicator of the drying capsule’s level of saturation (see diagram). The capsule features a small viewing window of sapphire crystal glass for this purpose.

The titanium drying capsule. As with crowns and push-pieces, we use EDR seals here, too.

2. EDR seals (extremely diffusion reducing)

To minimise the exchange of gas between atmospheric air and that inside the case, and thus the penetration of atmospheric moisture, we only use Extreme Diffusion-Reducing (EDR) seals in watches featuring Ar-Dehumidifying Technology. These seals reduce the infiltration of moisture in the case to as little as 25% of the value permitted by conventional case seals made of nitrile rubber (NBR).

All seals are made of sealing materials that are extremely diffusion reducing (EDR).

3. Superior protective gas filling

The Ar-Dehumidifying Technology is completed by a superior protective gas filling. This creates an ideal climate for the Ar-Dehumidifying Technology to function in. Only moisture diffusing from the air now has to be bound in the drying capsule. This avoids the humidity which is otherwise locked in during conventional assembly.