| 
Naar aanleiding van wat berichten in 'Dwellers Only' ben ik even op zoek gegaan naar de methodes van testen op waterdichtheid, ...met onderstaand als resultaat:
There are several different ways to test the seals of a watch, each has its limitations and advantages.
Vacuum testing
This is where you evacuate the test chamber and measure the deflection of the crystal, no, or little, deflection means the pressure as equalized on both sides of the crystal indicating a seal is bad.
Advantage
No water, therefore, no water can get inside the movement, even if the seals are gone.
Disadvantage
Vacuum testings is limited to something less that 1 atm. These also require very precise measuring equipment, as deflection is in the hundredths of a millimeter.
Dry pressure testing
This is the same as the vacuum test but uses a positive air pressure in the test chamber and measure the negative deflection of the crystal, again no deflection is bad.
Advantage
No water, therefore, no water can get inside the movement, even if the seals are gone.
Disadvantage
Require precise measuring equipment.
Water dunk
This is where the watch is suspended above some water, the pressure is increased, then the watch is dunked into the water and the pressure released. If there was a bad seal, the air inside the case would have equalized when out of the water and then when in the water and the pressure released, the air will escape and show up as bubbles coming from the case.
Advantage
Even though there is water, the pressure on the inside is greater that the water pressure, so no water will get in the case. Also, the origin of the bubbles will show where the seal has failed. Further inspection of the area of the bubbles will tell if it was something as simple as a pinched gasket or a pit in the case sealing surface.
Disadvantage
Water, if not done correctly, water can get in the case. Sometimes, if you are not careful, bubbles can form on the surface of the case due to surface tension and give false readings. These testers are usually limited to less than 5 atm.
High pressure water testers
These are just small pressure containers filled with water, the watch is placed inside and the water pressure increased to (possibly) several hundred atms by a simple fluid pump. The watch is removed from the tester and warmed to about 100 to 110 degrees, a drop of cool water is placed on the crystal and if water condenses on the inside of the case, the seals have failed and water has entered the case.
Advantage
Capable of testing to absurdly high pressures (125 atm or more). Very simple to make and operate (unfortunately, the price of the testers is not less than the other two.)
Disadvantage
If it leaks, water will get in the case. Should only be used in conjunction with one of the other types as a final check of the WR of the watch, or used as a case integrity test without a movement inside first.
(bron: Cachebestand van Google, bron geeft helaas een 'broken link'!)
...best interessant! 
| |
_____
Ex-Rolexverslaafde - Xs4all is ermee gestopt, waarmee mijn foto's ook allemaal foetsie zijn. Tja. | |
|
