With the development of the times, watches with waterproof performance (Water Resistant) has been widely recognized. For waterproofing performance, there are two common expressions, one is waterproofing depth (m), the other is compressive value (bar or ATM). The relationship between the two is that every 10 meters increase in underwater depth will increase the pressure equivalent to one atmosphere pressure, that is, 1ATM = 10m waterproofing. As for the waterproof performance of watches, the national and international standards have clear provisions: all watches marked waterproof, the minimum tolerance to two atmospheric pressures, that is, 20 meters deep water does not enter the water. Thirty meters waterproof means that the watch can withstand three atmospheric pressures, and so on. This standard is based on the premise that the test is carried out under laboratory conditions: the temperature is maintained at 20-25 degrees Celsius, and the watch and water are in a static state. In this case, a watch is qualified if it can be waterproof.
Practical embodiment of waterproof depth
Waterproofing specifications of general watches can be divided into the following categories: 30-meter waterproofing meter, which can be used in daily combing or rain, that is, water droplets only splash on the surface without any water pressure added to the watch; higher level, the most common indication is 50-meter waterproofing meter, which can be used for general household chores and showers; 100-meter waterproofing meter can be used for swimming and snorkeling, while only 200-meter waterproofing meter can be reached or exceeded. It is called a diving meter and can be used for underwater diving. In life, the arm movement of the wearer in water will greatly increase the water pressure on the watch, so it can not be worn to the theoretical depth indicated by the laboratory test machine.
In the structure of watches, the greatest impact on waterproofing performance is the sealing gasket (0-ring). It is made of rubber, nylon or Teflon. A waterproof seal is formed at the joint of the crystal glass, the bottom cover and the crown and the case. If it is a chronometer, its propeller will also have a gasket. Waterproof case lining to seal the coating to prevent seepage. At the same time, the thickness and material of the case can also determine whether a watch can be safely worn underwater.
It is noteworthy that, according to the rules issued by the Federal Trade Commission, watches sellers should not label their watches as "completely waterproof". Even watches designed for deep-sea diving cannot be claimed to be completely waterproof. Watches are not permanently waterproof and are affected by wear or time. The gasket may be corroded or deformed, the case may be damaged, or the crystal glass may be loosened or broken.
The infinite desire for knowledge and conquest of the mysterious ocean has led many adventurers and even watchmakers to devote themselves to the study of the ocean at all costs. The diving table is the real witness and shocking result of this exploration process. The difference between waterproof meter and diving meter is that waterproof meter is only designed for daily life, while diving meter is a professional precise timer to ensure a certain degree of pressure resistance at a specific diving depth, to ensure that the real record of time. The powerful function of the diving meter, the masculine sportsmanship and the significance of exploring the ocean make many men crazy.
Structurally, diving meters often use threaded crowns to prevent water from penetrating through rotating holes. The tight watch on the crown will form a waterproof seal, just like the seal between the wide-mouth bottle and the screw cap. The gasket is made of helium which can withstand the pressure reducing chamber of divers. Some watches have valves that allow the wearer to release helium that seeps into the watches so that when the watches and divers are adjusted to normal atmospheric pressure, the case does not burst. Usually diving meters should also be equipped, including: rotating outer ring for measuring diving time (designed to prevent reverse rotation); night light pointer and calibration for reading time in dark seabed, etc.
Since Rolex introduced its first oyster watch in 1926, the wide field of diving meters has been opened up. Since then, many watch brands have their own diving watch series, and many watchmakers and brands have begun to manufacture high-performance diving watches for professional diving agencies or the army, including Panerai, which started diving for the Navy. With the progress of science and technology, super diving depth is also a major watches brand research and development project.
On January 23, 1960, the Trieste in a deep-sea submersible dived 10,916 metres below the surface with Rolex's wristwatch in the Mariana Trench. This expedition into unknown waters successfully rewrote the history of human conquest of the sea. Fifty years later, this record has not been broken and the depth of dive is beyond reach. As a result, it has become a landmark event for mankind to explore the deep-sea world, and at the same time, it has greatly strengthened the consciousness of human protection of the ocean. However, it is very difficult for people to get to the depths of more than 1000 meters underwater in life, but this does not hinder people's enthusiasm and concern about the diving meter. The mystery and longing for the ocean, as well as the high degree of integration of technology and machinery, even if not worn, do not affect them to become excellent collections.