By David Baines, International Sales & Marketing Director, Molecular Products Limited
SubscribeMolecular Products Ltd specialises in manufacturing chemical absorbents, chemical based devices and catalysts, all of which are used for emergency air purification.
Committed to the future of leading edge technology, Molecular Products is recognised as a global leader of life support equipment. It specifically provides systems for the removal of carbon dioxide and the provision of pure oxygen in sealed environments which include submarines or shelters used for protection in the event of chemical or terrorist threats and external hazards.
Molecular Products has been supplying emergency air purification products to the Royal Navy for more than 15 years. The company also supplies other armed forces and navies across the world including those in Australia, Canada and the USA.
Recognising that many of its products are used in critical applications, often protecting life or the environment, Molecular Products' paramount global focus is on best quality, consistent and highly reliable products.
The company's most recently developed product is the Portable Atmosphere Control Unit (PACU) which has been designed to maintain a safe and breathable environment specifically for up to four people in a confined space (approx 40m³) for up to 24 hours. The unit was conceived from the joint development of another product with the Royal Navy.
Within a sealed environment, it is essential to control CO2 levels by removing the CO2 at a rate at least as high as the production rate. Fresh oxygen must be added when the level begins to significantly reduce.
The PACU is based on advanced submarine technology, through which its purifying elements absorb the produced carbon dioxide and replace oxygen consumed by human respiration. The modular nature of the unit's design allows it to be housed within a variety of different configurations.
The technology used within the unit is developed and proven in large submarines for both routine and emergency disabled submarine use. Its unique characteristics make it ideal for smaller manned submersible vehicles. The PACU's combination of chemical oxygen generation and chemical carbon dioxide absorber technology provides a safe and fully automatic atmosphere control system.
When used within a manned submersible, the unit allows the crew to concentrate on the mission without the time consuming job of monitoring and controlling life support systems and operations. It also makes efficient use of the limited space within the submersible whilst removing hazards associated with stored pressure systems.
The PACU provides an alternative solution to oxygen supply, as when oxygen is usually supplied in pressurised bottles, it creates major issues which must be addressed. Storage efficiency can be poor due to the weight and size of pressurised oxygen bottles, they also add to maintenance costs as they regularly have to be taken out of commission for regulatory visual and pressure testing.
Classification rules within the majority of small commercial submersible craft prevent stored volume within the pressure hull; therefore bottles have to be externally hull mounted which also creates the problem of corrosion and through hull fittings. The technology and efficiency of the PACU can avoid virtually all of these issues.
The PACU monitors and automatically responds to environmental changes, such as if oxygen levels fall below a predetermined level (usually 18% O2), the unit will electrically fire up an oxygen generator to restore the levels. As the unit is electrically initiated, low voltage is used for safety.
Within a confined, sealed environment, such as a submersible, it is the CO2 levels which cause an immediate threat as they build up to unacceptable levels long before the O2 levels fall to a level which has a significant impact on humans. The immediate challenge is therefore to control the CO2 levels to maintain a comfortable environment.
In addition, the PACU ensures that excess oxygen levels are not added as although not usually harmful to humans, high levels of oxygen (above approx 30%) have a significant effect on the auto ignition point of some materials which may be present within the confined space.
The PACU contains oxygen candles which are combined with a Carbon Dioxide Self Powered Absorber (CASPA). Since the candles do not use compressed or liquid gas, they make ideal emergency stores. The CASPA uses alkali carbon dioxide absorbent media, combined in a filter housing with integral fan and battery. Whilst hydrogen can be produced by the battery, Molecular Products can provide a chemical catalyst system which effectively catalyses the oxidation of the hydrogen to react with oxygen and produce water.
The components have been carefully matched so that unparalleled absorption efficiencies can be achieved from CASPA. In addition, the PACU uses Self Contained Oxygen Generators (SCOGs). These units produce pure oxygen from solid state chemicals and can provide seven days worth of emergency oxygen. When both components are combined with intelligent electronics that sense the environment, the PACU becomes a simple, portable, easy to use unit that lends itself to maintaining a breathable environment in a host of military and civil defence applications.
The intelligent electronics within the unit enable it to fully function on demand with little or no operator intervention, requiring just the turn of a key to start the unit. This is both cost and time effective as it removes the requirement for users to be trained in monitoring the unit and changing and regulating flow. Its intelligence will also warn and advise action if any part of the system is not functioning or is not present within the unit.
The PACU is automatically controlled and maintained with or without mains power, therefore will remain functional even when external power is unavailable. The unit has full 24 hour back up power and a guaranteed shelf life of 10 years with full electronic real-time status monitoring guaranteed even when the unit is in standby mode. Throughout its life, the unit also provides a full incident logging.
The PACU is also ideally designed for use within command and control centres for rapid deployment in the event of a terrorist attack. Emergency services requiring their control centres to be situated centrally and close to the scene of any unknown gas or chemical attack would benefit from using the unit, especially in advance of the substance being identified. The PACU could supply emergency workers with a safe and breathable environment, for potentially 24 hours on battery power in its basic configuration, allowing them to focus on the situation at hand.
The unit could continue to be used after this period; however generator power and consumables would be required. In light of global terrorist threats and the UK government's commitment to ensuring that emergency services are fully prepared for potential attacks, the development of the PACU presents a portable, reliable and virtually self functioning solution to atmosphere control in an emergency situation.
By integrating a carbon dioxide absorber and oxygen generator into one unique package, Molecular Products has created a compact, portable unit that can clean the air in a shelter without the need for traditional filter and ventilation systems. It can be utilised alongside traditional NBC filtering systems, and hence has applications from battlefield shelters through command and control centres to military vehicles, including warships and aircraft.
As well as carbon dioxide absorption and oxygen production in the UK, Molecular Products also make high performance military grades of activated carbon at their USA facility in Colorado. A number of products are in development, including one that is active against anthrax spores. These can be used in Personal Protective Equipment or Collective Protection Filters.