SCUBA stands for “Self Contained Underwater Breathing Apparatus” and it is the paramount element of marine exploration.  

The major aspect that confines our time and experience underwater is the air that we carry in our SCUBA tanks.  Air, Ah!! It’s simple when we hear it as a term in itself. But when it comes to using air in SCUBA, we must understand its forms first.  

Right from our early schooling we have learnt that the air we breathe is a composition of nitrogen and oxygen majorly, as well as water, carbon dioxide, ozone, and many other compounds in small traces. But little did we know that the same atmospheric air is compressed, to utilize as a fourth form of energy in many industrial applications. The pressure range in which air is compressed depends on the use case. While for SCUBA, normal atmospheric air is compressed and filtered, so the divers can take more of it with on their underwater trip.  

Compressed air is the typical gas used for recreational diving, while Nitrox, Trimix and Heliox gas mixes are used for technical diving in deep waters. Divers use a pressure regulator (in their mouth-piece) to bring back the air from high pressure to atmospheric pressure (when at the surface) or the local underwater pressure, depending on the depth.  

While underwater, compressed air is utilized at varied levels which is a factor of the depth it is breathed at. For us to visualize – If you are a diver descending into the ocean, for each foot you will experience an increase in pressure by 0.44 psi roughly for sea water and this is a tad bit less for freshwater SCUBA as both the air pressure at the water’s surface, and the water pressure, will act.  

The scuba diver uses a mouthpiece with a pressure regulator to retrieve the air from high pressure to atmospheric pressure, or to the required pressure based on the depth. 

SCUBA tank filling air compressors are similar to the ones used to deliver air for firefighters and for oxygen tanks in hospitals but the vital difference is the pressure and compressed air quality output from the compressor. 

1. Pressure

For SCUBA, when compressed air is being used, based on the way air is carried, a low pressure or a high pressure compressor is chosen.  

a. Low-Pressure Compressors 

For surface supplied diving, low-pressure compressors are used. These compressors are lighter in weight compared to the conventional compressors so as to carry in flotation rings that float on the surface of water and they supply underwater divers with air via a hose. Typically pressure range for surface- supplied diving compressors range from 15 psi to 130 psi maximum.  

b. High-Pressure Compressors 

Divers carry compressed air in Aluminium or Steel tanks for breathing underwater, in this scenario air is compressed in ranges between 3,200 and 5,000 psi.  

The compressor’s Free Air delivery/ output flow is a factor of the tank size and number of tanks that needs to be filled. 

Compressed air quality 

For SCUBA it is mandatory that the compressed air is of breathing quality. A compressed air system can contain contaminants that affect the quality of breathing air from sources like compressor oil, system leaks, inadequate filtration and environmental variables. Hence filtration plays a crucial role. 

Mostly the filtration and moisture separation system is separated from the compressor system, hence downstream filters, moisture separator and dryers are preferred, to ensure the compressed air complies with breathing air standards. Apart from regular filtration, the compressed air is passed through a sequence of activated carbon filters that gets rid of hydrocarbons and carbon monoxide (CO).  

We must keep in mind it is important to choose the right compressor that inherently does not pass over excess moisture, oil, dust particles and other contaminants as excess moisture can cause overloading of the drier, and moisture separator. If left unnoticed, it may lead to deprivation of compressor filtration, fault in regulators, corrosion and oxidation of scuba tanks. While excess oil could increase excess CO, CO2 and hydrocarbon levels in compressed air. 

In order for humans to have a safe and fun underwater experience, making sure you have the right tank and air supply is essential for a successful dive. At ELGi, all our compressors are built with best in class features unique to our brand for keeping moisture and oil carryover as much within the limits as possible. We study the application in-depth before suggesting the compressed air system with the suitable air quality and right size.   

Schedule a call with an air expert here: https://www.elgi.com/in/contact-us/  

Author – Gopikrishna 

However, not many are aware that compressed air is a major power source in the healthcare sector and saves many lives. It is a key component that enables the functioning of modern medical equipment. Be it artificial respirators or surgical instruments, air compressors power a number of systems in hospitals and dental clinics.

Let us look into some of these in more detail:

Operation theatre

Medical-grade compressed air, free from contaminants such as oil, dust particulates, bioburden and water vapour, is administered to patients for anaesthesia and inhaled medications during surgeries. It keeps them with breathing and makes them feel comfortable during invasive procedures. Air compressors also help run several handheld medical tools and pneumatic devices in the OT.

Treatment of severe respiratory conditions in the ICU

Life support systems in Intensive Care Units (ICUs) are powered by air compressors. Medical grade air compressors deliver clean and dry air while running ventilators. They also power the incubators that provide a safe space to new-born babies as their vital organs develop. The controlled flow of air helps reduce unsafe levels of oxygen exposure and enables easy breathing for patients.

Dentistry

Air compressors are also at the core of dental treatments and surgeries. They help operate drills, scalers and other handhelds used by dentists in tooth extraction, root canal process, teeth cleaning and other invasive procedures.

Besides providing the cleanest of air for equipment, dental air compressors must also function without making much noise – this is necessary to enable dentists to focus on their work and the patients to stay relaxed. Small air compressors with filter silencers can significantly reduce the noise a unit makes.

Hospital maintenance

Compressed air is the best resource to clean dusty surfaces in any facility, making it useful for hospitals that must be kept very clean. Air compressors also power a number of other tools used in the repair and maintenance of medical equipment such as nail-guns, impact hammers and others.

Hospital maintenance teams also use air compressors to inflate mattresses and the tyres of wheelchairs, stretchers and service carts.

Air compressors that supply medical-grade air

Medical air compressors are specially designed to distribute air that does not have any traces of fine particles, oil, odour or moisture. Such air is used only for patient care and calibration of devices for respiratory applications.

Oil-free air compressors are the best models to supply medical-grade air Since they use materials like Teflon for lubrication, there is no trace of harmful oil in the air output of these compressed air systems.

It is also critical to eliminate water from healthcare compressed air systems because moisture is corrosive and can cause significant harm to the units. Besides damaging distribution pipelines and air receivers, it may lead to mould growth on equipment used in medical treatments. Water can also freeze in control lines during cold weather, resulting in faulty operation of associated applications.

Regardless of airborne moisture or vapour from system condensation, water in any form is harmful to systems run by medical air compressors and can lead to multiple breakdowns and repair bills.

More alarmingly, any bacterial contaminant or pathogens mixed with moisture, put patients’ lives in danger, defeating the very purpose of using compressed air in medical facilities.

Smooth functioning of air compressors

The key component requiring maintenance to avoid water in medical air compressors is the air dryer. While buying accessories, ensure that you choose the right size of dryers and fit them carefully, considering the amount of moisture that they can hold.

Service or replace the dryers when required because, in time, they tend to lose their ability to stop vapour from passing through the air compressor.

As part of your routine air compressor maintenance, check the condensate drains to prevent them from carrying moisture downstream into the linked medical systems. Get the clogged drains cleaned thoroughly and if there are any other signs of damage, contact a professional to make necessary repairs or replacements.

ELGi offers air compressors and accessories for the healthcare industry for select applications and to support your facility maintenance tasks. To know more about these models or to sign up for an annual maintenance package, contact our team at 1800-425-3544 (India tollfree) or write to us at communications@elgi.com .