Often the quality of many filling stations is very bad. The devastating consequences, particularly for health, do not spare even the diving equipment: tanks and regulators.
The user can only detect the bad smell of the air or put in front of the open tap of the cylinder, a white handkerchief to show any stains due to air pollution
This is not enough! You should see what is in the cylinders and regulators to understand the seriousness of the problem!
The next picture shows the inside of a cylinder on the bottom of which you can see a pool of water mixed with oil. The steel cylinder body is severely oxidized. These cylinders had been delivered to us by a client to send it to the test center.
Diving equipments damages
that in general the corrosion is detected in the inner parts in contact
with the air "breathing" rather than in areas exposed to corrosion of
the external environment! AIR bad quality 'can do much more damage than salt!
The following image shows a series of steps before we were given for maintenance, but the condition of chrome parts have forced us to throw them!
quality should be guaranteed, in Europe, by law in accordance with specifications
(DIN EN12021, Gio DIN EN 3188) but in reality the control is limited to
certifications required to sell a compressor. The
next inspection, which into Italy should be implemented by the departments of
environmental hygiene of the ASL, are virtually non-existent!
We try to analyze the causes that lead, often, the diver to breath .....unbreathable air and its consequences!
The next image shows the corrosion that has developed under the air-water boundary
Intoxication during the dive You'll often hear divers complain of "smell" that emits air cylinder or headaches own to the bad quality. In reality it is an intoxication, which furthermore is amplified by the pressure
Well, in fact: bad! What the divers breathed air that is not only "smell" but oil vapors, oil that if should be also a cooking oil, at any rate would cause a lung disease due to the fact that these oil soaks: the lipoid pneumonia!
Instead it is machine oil, aggressive and not food, so that when you change the oil to the compressor is necessary to wear gloves to avoid skin irritation phenomena which also affects less prone to allergies!
Here's how it appears histological examination lipoid pneumonia: it 's yellow area highlighted by red circle.
oil lubricant, due to the temperature developed during the charging
process, undergoes further transformations that increase the power
aggressively to health of the diver.
It 'obvious that in addition to lipoid pneumonia is a risk of lung cancer!
Radiograph next refers to a person who has contracted the lipoid pneumonia. The picture is similar to those in situations related to cancer
The compressors for filling are made, typically, by three "stages", each stage consists of a cylinder in which slides a piston that compresses the air. This system is lubricated and, therefore, the piston is provided with piston rings which, as a piston of an engine, also have the function of preventing, as far as possible, the oil passage towards the head of the piston.
The compressor stages are "connected in series", in this way, the air passing in sequence the various stages undergoes successive jumps of pressure and temperature.
To keep the temperature within tolerable values by the materials, the air passes from one stage to another along a coil cooled by a fan connected to the compressor shaft.
The cooling condenses the moisture in the air and the oil that is "drawn" through the bands: these two products, mixing, forming an emulsion which is discharged to the outside of the circuit of the compressor by means of special valves.
Most of this emulsion, said "Condensation", is eliminated in the passage between the first and the second stage, the steps between successive stages eliminate part of the residue. The air escaping from the last stage preserves in every way a certain amount of condensate which must be eliminated by a special filter.
The filter consists of a container that houses a cartridge containing two different elements: the molecular sieve and activated carbon. Faulty are separated by felts that have also The task of filtering the "particulate", The air passes in the first part containing the molecular sieve that is used to eliminate the residual moisture, subsequently passes into the part containing the activated charcoal, which has the task of purifying air from hydrocarbon vapors, acid substances and pollutants of organic nature, such as microorganisms. To ensure the proper air purification is necessary to use filter cartridges that are prescribed by the manufacturer, among other things, stored under vacuum.
Filling System Management
- It 'important to respect the specifications of the compressor's builder.
- Do not recharge on its own filter cartridge, if it were absolutely necessary, it is essential that you use the products according to the specifications of the manufacturer of the compressor and make sure that they have been kept under vacuum. Tests performed with a system capable of analyzing the output air from the compressor have shown that the products (molecular sieve and activated carbon) that have not been stored under vacuum are absolutely inefficient.
Good quality compressoers
It 'obviousthat the compressorsofgood quality and wellmaintainedcanensureabetter air quality, whichisespeciallyconnectedto thesealingof thepiston rings.
A compressor whichconsumesoil is nota machineable to providebreathable air,becausethe oildispersed ends upin the filter, making it immediatelyineffective. Acharging stationthathas invested ina compressor"brand"is generally moreattentive toqualityand servicethat wants to offer.
It is a refrigeration system that cools the air in the compressor outlet.
As we have seen the compressed air is cooled by special coils placed in the flow of the fan of the compressor, despite the presence of this system, the outlet air temperature from the compressor is very high. An additional system of refrigeration is able to lower the air temperature up to only +3 ° C, thus most of the residual vapors condense and are ejected before reaching the filter.
The duration of the filter depends on the temperstura outlet gas from the last stage, a filter that has a duration of 33 hours at 20 ° c, 35 ° c lasts only 10 hours if the air is cooled to 3 ° c * the life of the filter increases up to 6 times in normal conditions and up to 10 times in a tropical climate.
Apart from the economic factor, this system provides an additional assurance on the breathability of the air supplied by the compressor
Is very important to know what we are entering into cylinders dedicated to breathing underwater, there are tools that can analyze the air leaving the compressor. For a good monitoring is sufficent to measure the residual moisture which index the proper functioning of the filter. Such a system should be required by law.
Obviously there are tools that can analyze various pollutants such as: hydrocarbons, carbon monoxide, etc..
These instruments, definitely more expensive, are desirable, but in order to measure continuously the residual moisture in all the charging stations would be the achievement of a great achievement, in fact the filters are constructed so that the molecular sieve is exhausted before of active carbon: in this way the increase of humidity in output indicates the exhaustion of the filter.