Saturation Diver with Diving Bell and Thanatos
本文同时提供以下语言的翻译:中文
Introduction
Saturation Diver is a little-known high-risk occupation.More than 100 meters underwater, in the pure black water, the operation continues with only a few supply pipes and a faint overhead light.
Surrounded by darkness and the unknown,
Feel a sudden rush of water and see nothing.With psychological stress, unstable conditions and equipment that can go wrong by negligence, a single misstep can kill these divers in deep water.
What is saturation diving?
In water, for every additional 10 meters of depth, the water exerts an additional atmospheric pressure on the object.
For example, a balloon filled with air will be smaller 10 meters underwater than it is at sea level,
As the depth increases, the balloon becomes smaller ( and denser).On the contrary, when the balloon rises, the pressure decreases, and the balloon grows in size, returning to its original size when it leaves the water.
It is important to note that in scuba diving, the diver is always breathing.This causes the inert gas to dissolve more in the blood, and if it rises rapidly, the volume of bubbles in the blood increases, causing irreversible damage to the body.
That’s why it’s mandatory for scuba divers to make a safety stop when diving more than 30 meters.
In 1957, George Bond at the Naval Submarine Medical Research Laboratory demonstrated that humans could actually withstand prolonged exposure to high pressure through saturation diving.
Specifically through the chamber pressure, so that the dissolved inert gas in the body fluids in the body tissue of divers to achieve saturation.
All dives can stay underwater for dozens of days, after which the decompression time depends on depth, residence time, and breathing gas, but usually takes about half a month.
Meaning
Saturation diving allows divers to stay underwater for long periods of time, which saves money and makes divers more efficient.
Divers can be on standby in the diving bell’s living quarters in case of emergency.
Generally, saturated diving is mainly needed in the fields of submarine cable, oilfield pipeline underwater installation, rescue operations.
Diving Bell system
Saturation diving uses a closed bell platform that enters the water through a hatch at the bottom.
But the hatch is sealed as it rises to maintain internal pressure.At the surface, it locks into hyperbaric oxygen chambers, where divers saturate or decompress.
The bell is connected to the cabin through the bottom or side hatch, and a conduit in the middle is pressurized, allowing the diver to move to the cabin under pressure.
In saturated diving, the bell is the vehicle to and from work, and the cabin system is the living area.
The top of a diving bell is connected to a tube and a steel cable. The tube is used to provide helium-oxygen mixture, heating, and electricity.
Steel cables enable the ship to pull the diving bell up from the sea floor.
If the dive is relatively short (jump diving), decompression can be done in the bell chamber in exactly the same way as in the chamber.
Potential Danger
* sequelae *
Despite saturation diving, long-term deep-sea operations can still be harmful.The British Journal of Industrial Medicine documented that 40 commercial saturated divers with an average age of 34.9 years (24-49 years) were examined one to seven years after their last deep dive (190-500 m water).
Four of them lost their diving licenses because of neurological problems.Divers reported significantly more neurological symptoms.Difficulty concentrating and paresthesia in the hands and feet are common.
On neurological examination, they had more neurological abnormalities, consistent with dysfunction of the lumbar spinal cord or spinal root.They also had a greater percentage of abnormal electroencephalograms than the control group.
Neurological symptoms and findings were highly associated with deep diving (including deep) exposure, but more significantly associated with air and saturated diving and prevalence of decompression sickness.
Visual evoked potential, brainstem auditory evoked potential and magnetic resonance imaging showed no obvious abnormalities.
Four divers (10%) experienced brain dysfunction during or after diving;Two had seizures, one had temporary cerebral ischemia, and one had temporary systemic amnesia.
As a result, deep-sea diving may have long-term effects on the divers’ nervous system.
Accidents
After-effects aside, the smallest detail that goes wrong during a dive can kill the crew: not just the divers, yes, but the crew on board.
5 November 1983 Beford Dolphin accident, North Sea Oil field;The four divers returned from the operation, left the diving bell and entered the living room of the compression chamber to decompress.
Despite all the experience of the crew, Crammond, who performed the extravehicular separation, made a fatal mistake (presumably) :
After disarming the diving bell without confirming that the door was fully sealed, Crammond was shot to death by the pressure difference between the decompression chamber and the outside,
His assistant was seriously wounded.The four divers in the decompression chamber were even more miserable: nine atmospheres of pressure suddenly dropped to one atmosphere, pulling air out of their lungs and causing them to collapse.
The gas in the blood burst, causing the tissue to block the blood vessels, and he died instantly.
Wildrake diving accident, 8 August 1979, North Sea Oil Fields;Because of the rupture of the cable, and the misjudgment of the commander, all the cables connecting the diving bell broke.Due to the harsh conditions, it took 19 hours for the bell to be brought to shore. The two divers inside,
Richard Walker and Victor, died of multiple organ failure caused by extreme lack of oxygen and cold.
It took eight years for the oil company to admit its wrongdoing.
Several saturation diving accidents so far have been the result of human errors of judgment, and in the Case of the Biford dolphin, the Norwegian government did not mandate the use of a relatively sophisticated insurance lockout system.It is worth pondering that people attach importance to money and despise life.
But as technology matures, hopefully there will be no more accidents like this.
Citation
- Todnem, K., et al. “Neurological Long Term Consequences of Deep Diving.” British Journal of Industrial Medicine, vol. 48, no. 4, BMJ, 1991, pp. 258–66.
- “Byford Dolphin (09092)”. DNV GL Vessel Register. Det Norske Veritas. Retrieved 14 July 2010.
- Smart, Michael (2011). Into the Lion’s Mouth: The Story of the Wildrake Diving Accident. Medford, Oregon: Lion’s Mouth Publishing. ISBN 978-0-615-52838-0. LCCN 2011915008.
Saturation Diver with Diving Bell and Thanatos
