~ Sea Divers ~
Notes to assist "Divers" in respect of Surface Air Supplies:
Compressed Air Contamination -- Air Intake filter & noxious gases -- Oils for compressors -- Cooling for compressors -- Compressor capacity under load. -- Heat & water condensate -- Bacteria contamination due to moisture -- Activated carbon's -- capacity to cleanse fumes -- capacity to dry out air -- Filtration of - Water - oil - Air -- Air hose sizes -- Pressure differential, air - water --"Mental" capacity to rationalise irrationality under stress. Hypoventilation through fear or trauma causing death. Timbo's Safety Alert.
Compressed air contamination results from either contaminated air entering the compressor intake (dust or hydrocarbons from exhaust and/or other fumes), or from oil contamination during compression pumping. It also occurs after compression through air receivers contaminated by rust, bacterial growth, stale air, & dangerous Carbon Monoxide (CO) forming from overheated oil.
The air intake delivery line needs be of a diameter at least three times that of the outlet air or more, if there is a long intake extension line fitted. The intake filter needs be protected against the weather (water ingress), it needs be checked prior to each dive for free flow and free from water or other restrictions.
A 1-2 micron filter of adequate size is recommended for the air intake filter. Car filter inserts are cheap to purchase, readily available, adequate of size, and of 2 micron. The air intake filter needs be placed as far as possible from the petrol driven motor exhaust to ensure that wind gusts do not allow exhaust gases to be drawn in.
Also, the intake point must be well above any place in the boat in which carbon monoxide or gas from gas cylinders could collect, as noxious gases are heavier than air. ie. place the intake above the level of the sides of the boat as well as above the height of the motor exhaust.
Compressor lubrication - For your information I give extracts from a letter received by me from Brad Dawson of Castrol Australia dated 4.4.96 ... Quote -
Vegetable oils are not suitable for high temperature applications (eg compressors) as they oxidise readily at above 70-80 degree C, a compressor on vegetable oil would quickly become choked with deposits.......The benefits of using a dedicated compressor oil are:
Better resistance to high temperature oxidation and better water separation (demulsibility)........
The main factors influencing oil consumption are viscosity and volatility........Synthetics have by far the lowest volatility (evaporation) level........Synthetics give by far the best performance due to low consumption and up to 5 times the service life .........
The additive levels of compressor oils are very low (compared to engine oil)..... with typical additive contents less than 5%.......... all additives are toxic. The maximum operating temperatures would be as follows:
Vegetable - up to 60-70 degrees, mineral - up to 90 degrees. Synthetics can operate consistently above 100 degree C without any problems..... unquote.
The synthetic oil the best lubricator in rotary compressors, and gives the lowest carry-over of oil into the air delivered. Remember, to only use a "dedicated" compressor oil, this is an oil that is specifically designed for air compressor lubrication. Compression of air can result in high air/oil temperatures.
As compressors are not internal combustion motors, they are free of contaminants resulting from internal combustion, and thus the dedicated oils used are more free of dangerous additives.
Also, some people use non-dedicated compressor oils merely because they have a high flash point, meaning that they can run hotter before "burning" which releases fatal gases. A high flash point oil does not necessarily mean that it is a good lubricator, eg: hydraulic oils.
The use of a non-dedicated compressor oil probably means you may be using an oil having either excess additives, or as in medicinal oils such as Ondina, no antioxidants, and thus one that may also run hotter if it is not a good "lubricator," thus wearing out your air pump quicker, with the further consequence of allowing up to ten times more oil vapour into the airflow through overheated & worn cylinder barrels.
This increases filtration demands and also the danger to divers if the filtration is inadequate or used in excess between changes.
For many years people have been using medicinal oils. These oils have no antioxidants, thus they "break down" due to hot oil interaction with the water in the air, resulting in poor lubrication and the formation of dangerous CO gases during partial vapour burning.
Shell recommend to use only Corena P 100 grade oil in piston compressors.
Operational Cooling of compressors - most small air compressors (under 75 kg weight of around 8 to 50 cu'/min) that are commonly used by "Hooka" divers are not designed for continuous "on line" pressure operation. They are designed for a 60/40 combination.
This means that they are designed to pump-up the receiver and then cut off. This "off" time under no load (freewheeling) allows them to cool, and as air consumption takes place, they switch on/cut-in again automatically as the pressure drops.
As diving operations often use petrol driven motors that are required to run continuously, it is important to only use a compressor/motor unit that has the capacity to deliver double the maximum air supply needed. This will allow the compressor to cycle in "free wheel" mode for a time after it has pumped-up the air receiver tank.
This "rest cooling time" requires the use of a "Genii" or similar pressure operated valve that shuts off the pressurised air line to the tanks, and vents the cycling air to atmosphere, thus allowing the pump to have an un-pressurised free airflow through it that cools it. To this unit can also be attached a throttle control that slows the drive unit/motor down to 'idle,' conserving fuel and minimising wear to "driver & driven." And easier on the "deckie's" ears.
As the air receiver pressure drops, the throttle opens and the pressurised supply reactivates to pump up the air tanks again. The larger the air storage, the longer the "unit" rests between pumping up mode and better cooling occurs. As the compressor now runs much cooler, wear is reduced, the compressor runs more efficiently (air delivered) and there is far less chance of oil carry-over in the airflow from heated gases being generated.
Operational compressor air requirement. It is recommended that doubling the total max depth air requirement figure be used in calculating air compressor delivery required for maximum optimum safe supply to diver/s. Taking into account that at each additional 30' depth, the air needed through pressure depth increase is an additional atmosphere for each diver, eg:
One diver air per minute at sea level needs 30 L/min (As 1 cu' min = 28.4L) Therefore compressor capacity needed is:
@ 30' = 60L/min approx
If you feel you need "more" air per minute than this table, use your figures.
compressor needs to run on 60/40 basis, it means it must be
"off" 40% of operating time ( free wheeling with nil
load pressure ) to ensure adequate oil & unit cooling and
maintaining a safe standard of operation.
Thus a compressor needing to supply the above 150L/min during its 60% "on load delivery" capacity cycle, needs to be able to have a 100% capacity supply of approx 250 L/min for a single diver operation at the above max depth of 120'. Doubling the 150L needed, gives a compressor requirement output under load of 300L/min.
working at max depth of 30' using 60L/min each = 120L/min, need
the following: 120L x 2. = compressor air delivery capacity of
200 - 240L/min.
working at max depth of 90' using 120L/min each = 240L/min, need
the following: 240L x 2. = compressor air delivery capacity of
400 - 480L/min.
With the 50%
additional capacity, the compressor is being given an
adequate "off load time" slightly above
manufactures specification of 40%, and thus giving more "leeway" for underwater
safety. You choose your "safety
compressor free running (not under load) @ 1400 rpm that delivers
22/cu/'min from its "swept unloaded volume," may only
deliver 11.5 cu'/min under load at 100psi pressure, being some
320 L/min. that is only half of the "advertised"
free of pressure air swept volume capacity at a given revolution. Showing that we need to ensure our air pump has adequate
capacity under pressure & at depth, when divers may breath faster and require
more/faster air delivery.
can be "speeded-up" to give additional air volume, but
it is surely wisest to stay within the manufacturers
recommendation, and design your unit to meet your need with
quality capacity and power to spare, rather than struggle
with an under capacity unit being stretched beyond its mechanical
and your biological limit.
Filtration of Air - water
and oil. The air filtration has been spoken of ref:
air filter prior to compression. Air has the capacity to carry
free water. Free water condensation takes place when air cools from
expansion when changing to a lower pressure, as well as when warm air is met by
a colder situation, being another air mass or material.
During compression, air temperature is heated considerably higher than the ambient (outside) temperature. The compressed and heated air flow is then constrained by the very pipe along which it is travelling, until it enters an area where it can expand, the expansion causes it to cool rapidly and water condensate forms.
type of filter is an expansion chamber that can permit water
condensation to occur. If there is adequate cooling in the after piping
prior to reaching the filter, then the amount of water condensate is lessened.
need for a compressor to have not only a fan type pulley that
itself keeps the cylinder head and compressed air as cool as
possible, but the compressed air needs to be cooled with the aid
of a water coil over the side of the boat, lowering it to 10
degrees below ambient if possible, prior to filtration.
Wet air or
dry air ? - the air that we breathe is natural, moist and
soothing to throat and lungs, and if dried out too much, we would
suffer respiratory problems. Air being compressed will by this
very cooling after expansion process dry it out to a point drier
that when it entered the compressor. "How dry" is dry
enough to filter it of its impurities, and "why dry" at
causes metal cylinders to rust. Diving tanks and storage air
receivers have for many years been of mild steel, as have air
receivers in compression charging facilities. To minimise the
problem of rust contamination of these cylinders and air tools
etc, "agencies" do their best to supply "dry air,"
not considering the unnatural implications for the "breather."
Certainly water carrying oil vapour needs be separated as does the oil as much as possible prior to final filtering. If it was not, then the absorption capacity of the final filter pads & activated charcoal would not last long.
charcoal/carbon is manufactured from Wood, coal, peat, or
coconut husk. It is "activated" by heating it in
nitrogen, this opens up the pores, resulting in a highly
filtrative medium. The hardest and best, and the best resistant
to breaking down into dust is the coconut fibre. There are different
grades and sizes.
grade of not less than .5 mm up to 3mm mixed to give a good solid
mass is recommended. Maximum gas vapour absorption as used in gas
masks by armed forces is the Pica brand TE 90 (.5mm-1.7mm gran)
and TE 50 (1-3mm). This is available in bulk from Carbon products of
charcoal can be, and is used in industry to "trap" and
filter out oils, waxes and other "heavy" substances. It
can and does filter toxins even when saturated by water, i.e.: the
cleansing filters used in fish tanks. So a little moisture in the air or
carbon will not effect the carbon to the extent that it cannot filter.
It is but a
matter of "how much" carbon is used, and very
importantly "how slowly" does the air flow through the
carbon filter, too fast, and the filtration can be nil,
too slow or slowly, and you are 101 + % safe. How good is your filter ??
Manufacturers may state "7 cu'/min flow" etc, but what if you are using more air
? how much is the filtering process diminished, 10% or 90% ?.
are cautious about how many cu' air can be filtered before
changes are needed. Why use an expensive filter cartridge having
relatively small amounts of carbon, and lots of expensive plastic
holder, when you can charge your own everlasting filter contents
& pads for $ 5 that contains 4 times more carbon.! A narrow
bodied filter maintains a fast air flow through it, less time for
air/carbon contact. A wide bodied filter can "hold" the
passing air contact 10 times longer, assuring a good cleanse. Carbon monoxide & dioxide is not filtered by activated
carbon has the capacity to "draw out" large amounts of
moisture from the passing air, causing the air to become
excessively dry. This can be avoided by soaking the carbon
granules in clean rainwater over night, and drip drying them out
for an hour on a piece of newspaper before loading. If they are too moist,
the passing air flow will "dry them," if they are too dry, they will absorb
passing moisture until "saturated." Washing and loading with slightly moist
carbon eliminates carbon dust from the system, and ensures a "natural" moistness
filter mounted apart from the vibrating machinery is best, as it
eliminates carbon particle "break down" and powdering. The "Timbo's" Div-Air purification system has a fourth
dynamic centrifugal filter between carbon filter and diver to
catch any carbon particles that may pass the carbon filter due to
faulty loading by the diver.
Do not be
concerned with "cloudy" water vapour appearing in your
face mask, the air flowing down the air hose is cooling, and as
it passes through the small constriction of the regulator, it not
only speeds up slightly, but during expansion into the
mouthpiece, it suffers a pressure drop and condenses. No more
dangerous to you than the water vapour in the shower.
"wet" conditions in the system may allow bacteria to
breed. But a filter that is used or unused for a long time is also able to
be contaminated, as are air receivers that are made out of mild steel, that soon
become full of rust and dirty water, that will daily contaminate any air flow
way is to be able to frequently charge your own filter contents. This way,
when not in use, you can also leave it clean and empty.
Any system having all its air filters placed before it goes into the air storage receiver is not adequately protecting the diver.
activated carbon & filter pads filtration should take place
when the air exits the storage chamber. This will ensure that any
contamination from rust etc is also cleansed in the final filtering.
thing between the final filtration and diver should be the air
delivery hose. If your system has a very large storage chamber
that is left unused for any length of time, then it should be
disconnected from the final filter and purged with fresh air
before reconnecting and use.
filtration systems rely on the use of replaceable cartridges and
foam covers to filter oil and particles prior to carbon filtering. Any system that "catches" oil and requires the
'following" passing air to flow through that contaminated
medium is in itself a contaminator if it is not replaced
diving units are of stainless steel. The filtration
system combines "dynamic" filtration of water & oil
in stainless steel cylinders. This method does not use cartridges
or foam screens, but centrifugal and increased air speed impact
methods of extraction that are very efficient. Due to this, the
following on-going airflow does not need to pass through
previously collected wastes that "fell away."
activated carbon filter has been designed to be easily removable
and "upended," so as to load from the bottom, having a
perforated mesh screen welded on the top end. Spring loaded
underneath. Thus, no matter how much pressure of air is given,
the felt pad and its contents cannot be dislodged. The airflow
will only add to the compacting of the filter contents.
As the air
leaves this charcoal filter, it passes through a centrifugal
safety filter. In the event that the diver or operator loaded the
felt pad incorrectly, allowing activated charcoal granules to
flow past, they would all be trapped and separated out of the air
flow in this safety filter.
filters can monthly or as often as desired, be washed out and
maintained in a totally clean state at no cost to the user. The only
on-going cost is the activated carbon & filter pads in the final filter.
The stainless steel "Timbo's" carbon filter has a "body width" of 2.5" and is 4" long. Containing some 200 gm of activated carbon. This filter is removable and the contents changed in a couple of minutes. Thus it is easy to maintain good quality purified air at all times.
any bacterial contamination of divers lungs through the system,
both the filters and air receivers can be 'flooded" with a water solution
containing .05% Chlorhexidine (3 mil to 4 litres water approx), and left
standing full for half an hour before draining and flushing again.
ensures the destruction of a wide range of bacteria, thus
ensuring that the entire airflow direct to diver is kept pure. Done a regularly monthly or as desired basis. The "mouthpiece"
may be rinsed daily after use.
it is not just the filters that filter the passing air. Any
surface including hoses, filter and cylinder walls "pick up"
contamination over time as air flows past. Thus a good occasional
submerge in detergent, and/or total hose renewal is recommended
filter systems --Many filter systems today are designed
mainly for "on ground" operation, meaning that they
supply air to one or more operators working at one atmosphere,
breathing more shallowly than a diver, and also the filtration
system is on "stable ground."
operation is "unstable ground," in that there is
constant movement from both the vessel, as well as vibration from
the "Hooka" drive motor if the filters are attached to
the frame. Further to this, Many "modern" filters have
an "automatic" self draining unit at the lower end of
the filter housing. These types of drains need a clean product to
continue to function properly, or they can block up during use.
before, many air receiver containers are of mild steel, some mild
steel unit "frames" are even used as the primary air
receiver. It has also been stated that water separation should
take place before the air enters the air receiver.
If this does not occur,
then not only does a lot of water collect in the "frame" or receiver (up to 1
Litre per 5 hour operation), but it is "wallowing around" in rusty muck, and as
the boat "rocks," a sudden mass volume of water can be forced in one "swoop"
into the filtration system, totally engulfing it.
This can also easily occur if you have "plug in" connectors on your diving hose. If your hose is connected before starting up and pressurising the whole system, then as air is rising in pressure, the whole system slowly fills up, and air flows slowly through your carbon filter as it enters your diving hose to equalise all the pressure.
If your hose is not connected, and you have "plug in" connectors, there is a totally different unseen scenario. 100 metres of 10 mm hose can hold 7.8 L of air at 1 Atmos. If your system has been pressurised to 120 psi (8 Atmos), then when a hose is "plugged-in," 7.8 x 8 Bar = 60 litres of air will in an instant "swoosh" through the filtration system.
"connect" your hose, this incredible "surge"
of pressurised air will accelerate instantly through your filter
system, most carbon filters cannot properly cleanse this instant
volume of air, and it may allow contamination through to the
diver or cause partial or total flooding of filters in an "unclean"
system. Both occurrences are very undesirable.
your hose is connected before pressurising the system. If
you wish to "purge" the unit first, then do so without
the hose connected, and drop the pressure in the entire system
before reconnecting. Fast "bleeding" or depressurising
the system should be done at the air receiver and not from the
exit side of the carbon filter.
It is not
commonly realised how quickly we just "assume" that an
automatic operation is functioning properly. i.e.. An automatic
filter drain is working to its full capacity. I believe that the
use of a manual drain cock is better. This ensures that we
daily learn to check it as we manually drain it.
filter housing needs be large enough to accommodate the water
collected. It is also possible to have the manual valve open a
crack, so "direct air " under pressure keeps water
draining continually. How often do you look into your filters,?
most filter "bodies" are sealed and thus internal water
contamination is unseen.
delivery hoses -- When a hose has no airflow passing along it,
the whole hose volume is 'static" with a balanced pressure,
ie; 120 psi. As soon as one end is "opened' as occurs when
breathing in, there is a pressure drop at this point, and the
whole air mass in the pipe flows along its length to "take
up" the drop in pressure. The rate of flow and its volume in feet per
second depend on the pressure as well as the diameter of the pipe.
the hose diameter, and the longer its length, the more "pressure
loss" and "air delivery delay" to diver results
due to friction. This pressure loss causes a "slow down" of the air flow
as it commences to move from a standstill when you breath in.
the effect of restricting the volume of passing air to the
diver at the "moment" of inhaling. An adequate volume
means that you are "comfortable," any lack in volume
results in a negative "suck" on the divers part,
leading to distress.
The area of a "hole in the pipe," its circle area, is as follows: 3.14 x radius squared.
8 mm air delivery hose - 3.14 x 4 x 4 = 50 mm.
the hose internal diameter, the 'easier" the air will flow. If you are finding any difficulty with breathing, then
immediately rise up to shallower water. The fault may be one of
many causes. But it is for sure the direct result of a lack of
necessary volume of air to you personally at the depth of your dive operation.
may be a compressor that has not got the capacity to deliver the
additional air volume needed as you go deeper. It may be that the
filter system is blocked. Or it may be that your air line cannot
accommodate the extra volume of air flow needed. If you are "sharing" the
same feeder line, you need an adequate volume of air.
system incorporates an IA Receiver,( Instant Air Receiver). This
is only a small half litre cylinder (2.5" x 8")
strapped around the waist on a belt. The air pipe enters on one
end, and the regulator pipe exits the other. As the "inner" air pressure
is equal to the compressor 120 psi, the actual air volume in the IA receiver is
.5 x 8 bar = 4 Litres @ 120 psi.
present system is in any way lacking flow volume at depth or with
two divers breathing in at the same moment, this IA unit ensures
that at all times there is a lung full of air ready to be drawn
in with no delivery delay.
This is due
to the dynamics of air, in that in your present system, as you
are in the mode of exhaling air, the air flow in the pipe
becomes "stationary," or in a "slow" supply
flow if it is still "filling up" the pipe after your
last gasp for air.! Your compressor may have the necessary air
"Volume" production, but delivery delay through small
hoses could effect its "down pipe" flow rate.
and thinner the hose, the slower the air flows. The Pressure loss may be 5 psi or more, and a 100 metre length of
8 mm hose will have an air flow restriction many times more than
a 16 mm dia. hose of equal length.
With an IA receiver, the air volume needed for your next breath is still able to be flowing in and made ready in "bulk" during the time you are holding a breath of air or exhaling air. The time when in most systems the "down pipe" airflow is at a standstill.
applies to a two diver process. It means that you both have a fully
available unrestricted inhale that is not dependent on slow moving air needing
to travel down 10 feet of hose before reaching your chest cavity.
IF you find a situation
that due to "total" lack of compressor delivery capacity, or blocked filtration,
then obviously, even an IA receiver is not going to assist you.
The IA receiver is a unit that compensates for air flow loss down an air delivery pipe. It ensures that there is NO delay demand or volume restriction supply in times of great air volume need. Divers need to ensure they understand the capacity of the unit they use and its limitations as well as their own. The greatest danger to any diver is their own MIND.
IF your thoughts let you down - ahead you will frown, or maybe even drown!
differential -- How does this effect you ? Other than the well
documented known effects of changes that take place in the human
body due to depth, time immersed, and gases inhaled, that you
should be familiar with, there is another basic need. The need to
be able to "draw in" an unrestricted volume of air at
whatever depth you are operating.
effects this.? We have discussed compressor output capacity under
load (increasing in volume requirement) the deeper you go,
and flow pressure/volume loss due to friction in the air
delivery hose. The other factor, is relative to the
pressure differential between the air pressure being delivered
to your demand valve, and the pressure on you from the water
that surrounds you.
We stand on
earth with a pressure of one "Atmosphere," or one
"Bar." of 14.7 psi. It is a "balanced"
pressure to us (within & without) when the muscles in our
chest are "relaxed." Any muscular action that "raises"
the chest cavity permits a "partial" vacuum (lowering
of pressure) due to the immediate pressure differential created, thus the
outside air flows in.
pressure drop that our muscles can create on inhaling are about
minus 1-2 psi. The muscular force that we can generate on the
exhale by muscular compression of our chest is much greater, 7
psi and more. If we only need a 2 psi "pressure differential"
to breath in, why do we need such high in line pressures,
100 psi or more.? Because, these pressures are not only to
accommodate the 2 psi pressure differential needed to breathe,
but are needed to compensate for the increase of the outside water
pressure that increases the deeper we go.
pressure within our lungs increases as we dive deeper, and at all
times is "equal" to the outside water pressure. The
muscular activity that moves our biological diaphragm opens the
"mechanical" demand valve by lowering the
pressure in our mouth, at this moment, the "in line"
pressure with its "positive pressure differential"
flows in. At all times the "in line" air pressure must
equal or exceed the pressure of the water at divers depth, or we
would not be able to breathe in.
of water depth increases the "outside" pressure upon
your body by .5 lb. Thus at an operational depth of 100,' the
water pressure around you is 50 psi. The air pressure in your lungs would
also have risen to 50 psi to compensate.
If your air
delivery line and air receivers contained a pressure a little
above that 50 psi, eg 53 psi, then on breathing in, air would
flow into your lungs. However, a slow flow-in, due to a
low pressure differential of only 3 psi would put you
under stress, as this "initial" 3 psi additional
positive pressure would in fact drop, due to line friction flow
losses as you tried to breathe in "deeply"
through a "straw."!.(thin pipe).
"pressure differential" do we need to breath easy. ? If the air delivery hose was a foot wide,! then as on dry
ground, zero psi pressure differential would suffice.!
divers use hose pipes having 8 - 16 mm internal dia, a far
greater pressure differential is needed to overcome the time
taken for the air to "accelerate" and "move"
when the inhale action is commenced.
compressors deliver up to 120 psi. this is a 70 psi positive
pressure differential greater than the water pressure of 50 psi at 100'
at a depth of 120' you are quite "safe" if your air
receiver pressure is "operating" between 80 - 120 psi, as
long as your "demands" for air are met. Assuming that your compressor is of adequate air volume
capacity, your air demands will be met if you use a
hose of adequate diameter for its length.
Remember, that the deeper you dive, the larger the air flow volume your hose will be carrying, and whether there are more than one diver on a single hose, as this too may effect hose choice ...
The rational facts of the matter are:
The longer the air line is, the greater the air flow volume loss, due to friction.
The greater the depth of water, the volume of air use increases, maybe x 5 or more.
line added to a deep water situation x 2 divers and
you need a BIG hose pipe.
Why do we use "thin" hose for our air,? Cost, ? handling difficulties in and out of water. ? Why walk on thin ice ?
Why not combine two hose sizes if operating long lines, or deep water, or two divers ?
metres of 16 mm, reducing down to 8 or 10 mm for additional
length or doubles.
in flow volume/rate suffers a lot more pressure flow drag loss
as it travels down an air pipe. This "delay" in the capacity for the air
to "flow" can in itself create a "temporary" negative pressure differential at
the "moment" you inhale.
causes further breathing demands, and as your breathing
effort increases, that "temporary" negative pressure
becomes more severe and/or permanent. !!!... It occurs if
the air line is too small in diameter to accommodate users demands.
the pressure differential between the outside water pressure and
compressor air "in line," the less chance for
negative pressure drop to occur on inhaling. The IA receiver
"compensates" for "any" temporary partial
pressure drop on "inhale" due to either low partial
pressure in line, or slow air flow in pipe due to sudden great
air demands by one or more "on line."
The IA receiver is not a "substitute" for an "unseaworthy" air supply unit, it is an added safety factor to assist divers in times of physical duress and mental "stress."
purchase the correct size air supply unit for your
operational needs. Ensure that another's unit offered for your
temporary use IS of a capacity to suit YOUR needs.
Be aware that hoses can easily be sucked into turning propellers. If you are concerned that a hose may be cut by the boat propeller if the boat is being manoeuvred during diving, prop guards can be custom built.
If you are concerned, fit
a non-return valve in the hose line 10 metres from the boat, thus if the hose is
cut, all the air does not rush out, and no instant pressure drop to the diver.
Bigger diameter hoses hold
more air reserves. 16 mm holds x 4
more vol than 8 mm. 8 mm x 50 mtr holds 2.5 L. 10 mm x 50 mtr
holds 3.9 L. 16 mm x 50 mtr holds 10 Litres, x 8 Bar = 80 L
reserve, = 20 breaths at 90' depth. "Talk" is cheap, try
a 10 mm hose if on an 8 mm.
have an enormous "sponge volume." We can operate on as
little as 15% of their total capacity before we become aware of a
"clogging" problem (unless you are a runner). They can
"absorb" a lot of unseen contaminants over the years
from many sources before we notice it, but when we do notice the
effects of it, the process is usually irreversible.
"expressed" out of a compressor in three ways, as
"liquid," as "fine aerosol spray," and as
"vapour," The first two are easily extracted by the
"coalescing" of the water & oil that join together. Some vapour is also thus extracted as above if the system is
the easier it is for the oil to vaporise, and for the dangerous vapour to travel
through to the diver. So the more efficient the "after-cooler"
is, as in: "air coil cooled by compressor fan & water
coil," the cooler the air is, and the vapours coalesce more
easily with the water condensate, and are "collected"
by filter 1. And more easily the remaining vapour is filtered out
by the rest of the system.
compressor that is new or in good condition and one running
"cool," may use only about 1 ml oil per 100 hours
"used," thus oil passing into the system is minimal. A
worn unit may "deliver-up" 10 ml or more in this
time, and if it is running hot, that becomes a lot of dangerous oil vapour, and Carbon Monoxide
may be produced. Do you know how much oil is consumed by your
What the dynamic impact filter does, is to separate out
as much subsequent vapour as possible before the air flows to the
final filter. This "eases" the amount of effort
required by the final activated carbon & felt system, thus
ensuring at all times that the diver is receiving clean air. Even
if a diver is at times lax about changing the activated carbon
filter. It is a "safety first" system.
Clean adequate air is a daily must,
and a quality filter is of great personal value.
assume that another's unit has clean filters in it. It is your responsibility to open and check any unit
before diving, even your own if it was last checked the day
before. You are personally responsible for your daily actions. Never blame others for any reason.
check the positioning of the compressor air intake. It needs be firmly secured and situated in a safe place. IT is
the beginning of your "life line." Make sure
that all aboard the vessel understand its primary
function and "why" it must be well away from carbon monoxide fumes.
Any sign of loss of focus (disorientation,
or objects within your vision spinning slowly) when diving, could
mean contaminated air, surface immediately and as you so do try
to not inhale any more
contaminated air on the way up.
Even if you do not yet suffer any respiratory problem, disinfect the air and filter system monthly or so by flooding it with the prescribed or other good disinfectant. The air hoses may also be left flooded for an hour within the solution to ensure they too are kept bacteria free.
regulator mouthpiece should be daily "dipped" in the
solution and left hanging to dry. There is an enormous amount of
bacteria in saliva. Always flush out well any part of the system
that will remain "wet" after disinfecting. Any
disinfectant can irritate mucous membranes.
Purified safe air is the sum total requirement for the survival of your fleshly biological "spacesuit" on this material planet. Other than "air," it does yes need food and water. Its one thing to be a diver once a month for pleasure, but another to be a commercial operator. Good air hygiene !!
Acute emotional trauma
Be aware, that acute emotional trauma can arise from the emotion of fear. This may lead to a condition called hypo-ventilation that may result in unconsciousness and death. This may happen to divers that find themselves in a situation that 'arouses' a powerful emotion of fear. The paragraphs below are an extract from the 'suicide document' on the web site given, and the full text of pages 21-23 of that document need to be examined and understood by divers.
(See 'note' end of page 23 of the suicide doc - < http://www.the-testament-of-truth.co.uk/truth/web/suicide.htm >).
As said, the greatest danger to divers is ones "Mind." Within our physical body, is a spiritual one. IT dictates the actions of the fleshly body through emotions (feelings positive or negative) that are the "pipe line," the telepathic mental link (spiritual air delivery line) of thoughts, either (positive or negative).
If you find
yourself in a difficult situation, an emotion of fear may erupt,
IT has the capacity to allow confused thoughts to flash in. These
lead to not only panic, but to totally irrational deeds. Any intrusion of negative confusing thoughts needs be instantly
the mind, whether above or below water is most easily
accomplished by focusing on a given object. The best known, is to
visualise the Bright Morning Star. It is a consciously
visible sign of Light that can help to calm the rising
negative emotion and halt the irrational thought flow.
Try and see
clearly how man's progress has "evolved" through trial
and error over time. All progress stems from the "thoughts"
of man, many mistakes occur. If you as most of us, have suffered
the consequences of having heeded wrong advice, or denied good
advice given in any area, or used obsolete or faulty equipment,
remember, the fault is only your own. There is never a
time to "point the bone" so to speak. Go your way humbly and
Try and use only stainless steel air containers and compressor unit frame if it is to be used as an air container. This assists ensuring clean air. It is "irrational" to only observe the "outward" appearance of equipment. Your breath of life depends on what is "hidden" inside. Be it your soul or invisible air. Without exception, I have found that most people just "assume" their air delivery system will be OK. They also "hope" that the filters are adequate.
Do NOT rely
solely on what others say or offer - seek the truthful
reality for yourself, thus only is your destiny truly in your
own hand. Check ANY filter system offered for your use before
you dive, be it a friends unit or other commercial facility.
companies advertise "Diving compressor." You may "think"
it is a better machine than another. What determines a "diving
compressor"??. nothing actually. Most are basically just
piston driven air pumps, all with cylinders that require
lubricating with oil. All can contaminate the air. True, there are
some diaphragm types that are oil-free air delivery. You would
needs 'source' these yourself.
because one may have a different intake fitting for an air hose
etc, does not mean it is better than another. For "corrosive"
situations, I recommend an aluminium unit, less corrosion, also
compressors need a fan on the flywheel to cool cylinder fins.
"deliver" oil fumes, and may cause "partial
combustion," this releases carbon monoxide which may become of fatal
volume, IF you have a headache after surfacing, your unit IS releasing CO,
attend to it immediately.
mild steel parts on engines or boat fittings with "Techtryl,"
this inhibits rust for many years. A slow running "big"
capacity pump geared to low air volume output runs cooler, lasts
Man has for
ages time been "Hell-bent" on manipulating others
by control through regulation, This manipulation stems from some
"believing" that their "forceful" actions are justified, because "they" know
better than you, and: "It is only for your own good." Causing much suffering,
ill feeling and financial loss, that planetarily now leads to confrontation..
what life is all about, the freedom to choose. If
you decide to choose the foolish or dangerous course and end up
"on the rocks," that is your God given choice to so do. Personal responsibility.
truly the time for Education and not Regulation. Education, so that
you can be in a better position to make the correct
choice. So lets gather up our individual expertise and share it
around the planet for the benefit of all. Lets put "all the
food" on the plate, this way we will see what has
become "stale" and "contaminated."
What are your needs? What do you want changed ?
TIMBO'S 'Safety ALERT' Notice
For many years there has been a continuation of "bad habits" throughout the diving fraternity, as well as some diving compressor unit manufacturers by wrongly recommending the use of either vegetable oils or medicinal oils for use in air compression pumps.
This practice continues on today, in spite of many persons suffering either headaches, bronchial problems and/or death from Carbon Monoxide (CO) poisoning. Part of this "continuance" is because "new" operators ask "old" operators, and habits are hard to change.
Here is some information to you personally, be you an aqualung diver who "assumes" the air dive shop knows what it is doing, and for the dive shop operator, the "Hooka" user, or oil supplier.
Friction causes heat.
Heat also causes the partial "burn"
of oil vapour that results in Carbon Monoxide forming, thus
contaminating the air.
All refined medicinal oils such as Shell "Ondina 68" and BP "WM 1- 6" that have been "assumed" to be not harmful to humans are as "toxic" as any oil if they overheat. Not only this, but all oils release vapour at certain temperatures. Prolonged inhalation causes pulmonary oedema and consequent lipoid pneumonia. All oil mist interferes with the breathing process.
The refined medicinal oils listed above as well as many unlisted are refined to the point that they contain no antioxidants. Thus, oxidisation occurs easily with the resultant change in composition of the oil structure, heavy black deposits may form in the oil, and lubricating qualities drop, excess heat forms and partial vapour burn occurs, with the resulting insidious CO contamination of the air supply.
Any CO poisoning remains unnoticed when at an increased pressure depth. However it has a 300% more affinity to the haemoglobin than oxygen, and it rapidly displaces the oxygen from the haemoglobin. In the event that there is even as little as 5% CO contamination of the haemoglobin, there is an impairment to mental faculties, and on surfacing, the diver will get a headache.
that this percentage rises to 40%, it will still remain unnoticed
at depth, but on surfacing, the diver would suffer a collapse and instant
death. Any form of visual impairment or nausea/headache
on surfacing must be attributed to air contamination and
the mechanical problem rectified immediately.
Dioxide is also produced by partial combustion, it has a
distinctive odour, it causes emphysema, bronchitis and is an eye,
nose and respiratory passage irritant.
compressors MUST only use the correct "dedicated"
lubrication that contains the necessary additives and
antioxidants, and needs to be fan cooled or water cooled,
and run on a 60/40 basis to ensure that cylinder head
temperatures remain low, and thus there is NO partial
combustion taking place.
absolutely no effect on CO already formed in the cylinders, they are merely to
assist in reducing the volume of water condensate drawn out of the air stream.
NOTE: CO (Carbon monoxide) is not
removed by carbon filtration.
IF you are
using a piston compressor, use Shell Corena P 100, or BP RCR 100. If using a
rotary compressor, use BP RCS 100 or Shell Mandrela 68. OR the appropriate
oil from another oil company.
From tests run with a 5.5 hp motor with a 22
cu'/min swept vol compressor using the correct dedicated
compressor oil, the engine ran at 2740 rpm. Changing to
the non dedicated oil "Ondina 68," the revs dropped to 2650, a drop of 90 rpm,
clearly showing a loss of rpm due to poor lubrication.
How is your chest and head ???
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