Diving equipment

10/ژانويه/13

gasabeh.com [email protected] 1

BOVE AND DAVIS’ DIVING MEDICINE-CHAPTER 3

Copyright 2004, Elsevier Inc. All rights reserved.

10/ژانويه/13


-MASKS

-FIN

-SNORKELS

-BREATHING APPARATUS

-PERSONAL FLOTATION DEVICES

-HYDRODYNAMIC DRAG

-THERMAL PROTECTION

-DIVE COMPUTERS

10/ژانويه/13


-Air pocket over the eye

-Visual distortion

-VF restriction

-Pressure

- Volume changes with attendant discomfort

- irritation from chemical or bacteriologic sources.

10/ژانويه/13


-Visual distortion is the result of variations

in the distance from the mask lens to the eye.

-Air has an index of refraction of 1.0, whereas the index of refraction of water is 1.333

-Objects to be closer and

larger 10/ژانويه/13


MASKS

10/ژانويه/13


10/ژانويه/13


-Hypoallergenic silicone skirts and straps

are more comfortable, cause less irritation

of the skin and eyes, and are significantly longer-lasting than natural rubber products.

-Black algae and other organisms can grow easily.

10/ژانويه/13


-Lenses with the appropriate corrections can be placed in masks quite easily and

offer an alternative to contact lenses and

eyeglasses

10/ژانويه/13


Fluid Dynamics of Swimming

10/ژانويه/13


-Provide a greater resistive

surface to improve propulsion.

-The split-fin technology has achieved great popularity, and tests have shown them to be more efficient with less

noticeable leg strain.

10/ژانويه/13 -


The longer, narrower fins

tended to be slightly more efficient than the

shorter, wider fins and that fins with vents,

regardless of their direction, were not

superior to those without vents.

- The split-blade over the

solid-blade fins

10/ژانويه/13


A wider, slower kick

is more efficient than the rapid, shallow kick

often used by novice divers.

-Flutter kick

-Sculling-type kick

- Different functional muscle groups(to prevent fatigue)

10/ژانويه/13


-Snorkel tubes, used for easier breathing

while swimming on the surface, have evolved

from simple tubes that are open at both ends

to devices that offer purge valves, swivel

mouthpieces, advanced materials, and mouth-

pieces of improved design 10/ژانويه/13


-Long snorkels increase physiologic dead space and can lead to CO2 retention and hypercarbia. Excessively long snorkels should be avoided.

10/ژانويه/13


The snorkel mouthpiece should be able to

rotate on the snorkel tube so that the lip flange of the mouthpiece can be placed parallel to the teeth and gums. Blisters of the oral mucosa and T.M joint problems can result from poor alignment.

10/ژانويه/13


-The scuba, or self-contained

underwater breathing apparatus, used by

recreational, scientific, commercial, and

military divers.

-Permits divers to move independently under water

10/ژانويه/13


-Constructed

of steel or aluminum, but stainless steel and

titanium are also used.

-Inspected annually by a trained inspector

-Hydrostatic test procedure that is required every 5 y

-Volume:50-120 ft*3

-Do not breathe the cylinder pressure < 200 psi except in an emergency 13/10/ژانويه


-Inhalation and exhalation resistance of less than 3 inches (7.5 cm) of water

-First stage of the regulator, where its pressure is reduced to an intermediate

pressure of 130 to 150 psi.

-Sconed stage of the regulator, where its pressure is reduced to the pressure of the surrounding environment

and the diver’s lungs Advantage:dec pre-res work

Disadvantage:ignor dec pre of tunk 13/10/ژانويه


-Closed-circuit breathing apparatus consists of a mouthpiece and hoses

connected to a breathing bag, a carbon dioxide–absorbent canister, and a high-pressure breathing gas supply.

-Sensor-controlled rebreather

devices are typically set to hold the oxygen partial pressure between 0.5 -0.7 atm.

Advantage:dec weight-not bubble-

Disadvantage:hi expens-traini-low fsw-

o2 toxi 13/10/ژانويه


- The buoyancy compensator is used as a tool whose primary function is to

maintain the diver in a near-neutral state at any depth while maintaining a desired position, usually face down. -To accomplish this,

the device should concentrate much of the flotation near the center of mass of the body.

is not a life jacket 10/ژانويه/13


PERSONAL FLOTATION DEVICES

Life jacket

load-bearing jacket

buoyancy control device:

-an automatic inflation

-risk of confusion

10/ژانويه/13


-One liter of air displaces 1.03 kg of seawater (2.3 lb);

thus, a buoyancy bladder exerts 2.3 lb of lifting force for every liter of water displaced.

-Smaller buoyancy compensators have a capa-

city of approximately 10 L, whereas larger devices often have a capacity of 20 L or

more.

10/ژانويه/13


Fluid Dynamics of Swimming

10/ژانويه/13


10/ژانويه/13


- Drag develops in three basic ways during

diving: by frontal resistance, by skin friction,and by turbulent or eddy resistance. Drag is the sum of these three types of resistance.

10/ژانويه/13


HYDRODYNAMIC DRAG

10/ژانويه/13


- When a diver

enters water with a heat conduction capacity

25 times that of air, heat is conducted from

the body and adaptive changes occur to

protect the body from a fall in core temperature.

10/ژانويه/13


- The most common protective garment is

the wet suit , which uses a layer of air-impregnated neoprene rubber as the

insulating boundary to trap water next to the

diver’s skin as an insulating layer. A well fitted wet suit holds the water in place so

that heat is not exchanged by water displacement.

10/ژانويه/13


- Dry suits have become more popular in

recent years because of improvements in fit

and mobility. Comfortable insulating undergarments, effective valve mechanisms, and

better seals have also been added.

ROM-boyancy control 13/10/ژانويه


-These dive computers

monitor pressure and time; they then provide

information that can guide the diver through a

proper decompression.

-Computers are not risk-

Free.-Because there are no

“safe” tables or “safe” dive computers,every diver must accept some risk when

diving for sport or occupation. 13/10/ژانويه


-Dive computers cannot

guarantee that their use will preventdecompression sickness. Properly used, these devices should reduce the risk under normal circumstances.

10/ژانويه/13


Thanks for your

attention

10/ژانويه/13


Sports

Diving equipment