Introduction
Modern Diving Bells evolved from the first diving bells and observation chambers. Learn all about them in the Diving bell and Observation Chambers section of the Historical Diving section.
Diving bells
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Today, we still
find modern application of the old diving bell. It is a simple
transport-bell, used to transfer divers from the deck of the diving-vessel
to the area where they have to do their work and back again. In fact it
concerns a closed dome with a few glass view ports, standing on an open
construction, based on a working floor. The divers stand under the dome
during the transfer. The air-pressure inside of the dome is equalized in
accordance to the ambient water-pressure, so that the divers stay with the
upper part of their body in a dry surrounding. Once arrived on the
required depth, they bend down and leave the bell through the openings in
the side. When the work is done, they enter the bell again and are
hoisted back to the surface. Dependant to the time and depth of the dive
the decompression can take place by pulling up the bell to the different
depths and keeping this during the needed decompression-steps on certain
levels (wet decompression-system).
To keep the bell in a
vertical position, it is provided with a ballast-weight. To keep the dome
free of water, the bell has an air-supply from the diving-vessel. For
emergency-cases there are built some cylinders with compressed air mounted
outside of the bell, that can be opened by the divers. In general these
transport-bells are equipped with a telephone communication with the
diving-vessel and an electric illumination system. The bell can be fitted
out with oxygen masks that can be used during the last
decompression-stops. |
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2 divers in a LS 370 series wetbell on their way to work. This is a safe vehicle for manned intervention to the limit of the air range or to 100 meters on breathing mixtures. There are several options like guide wire system, heave compensation, automatic umbilical handling etcetera. Courtesy of Southern Oceanics. |
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Diving Chambers
Despite the use of saturation diving techniques, decompression still is a long-winded process. A diver can reach a depth of 65 meters in 3 minutes but it can take him more than 2.5 hours to return to the surface because of his decompression stops. It is very dangerous not to obey the laws of decompression. This was a big problem in the use of divers in commercial jobs. The question was: How can we lift the diver to the surface without shortening his decompression period ? The answer was found in the SDC (Surmersible Diving Chamber).
| Diving-chambers
are in fact pressure-vessels, that are used to transfer one or more divers
from the surface and back. The diver(s) can leave the chamber at the
required depth by opening a hatch in the bottom, after the pressure inside
and outside the chamber is equalized. The divers do their work in the
vicinity of the chamber and are controlled by a man who stays in the
chamber (the "bellman"). When work is done, the divers return to
the chamber and close the hatch again, followed by the pulling up of the
chamber to the diving vessel. The decompression can take place in the
chamber or after the diving-chamber is connected to a large
decompression-chamber. We will go deeper into this diving-system
(sometimes called bounced diving) later. First an article about
decompression-systems will be published. For more information you can also
see the saturation diving
section.
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Refurbished 2 person diving chamber, courtesy of SMP |
