Health And Safety Risks Of Compressed Air
There are significant health and safety risks associated with the use (and misuse) of compressed air. The force of the high-pressure compressed air exiting a nozzle can be as damaging as being hit by a solid object.
Compressed air can cause industrial injuries – and even fatalities if air bubbles enter the bloodstream and reach the heart or brain.
Air knives are much safer than compressed air. (They’re also up to 90% cheaper to operate.) Here are five reasons why air knives are the smart choice for safety…
1. Air Knives Don’t Need An Emergency Stop
Blower-driven air knives operate at such low pressure – they’re so safe – that they don’t need an emergency stop button.
That’s one less thing to specify, to have to maintain, to be inspected regularly or to worry about. It makes all the internal ‘politics’ of specifying extra equipment for your production line easier to negotiate (in both senses of the verb).
This simplicity and lower risk ensure it’s easier to comply with the stringent safety requirements outlined in the EU’s Machinery Directive and its equivalent UK legislation.
There’s an old saying in procurement: “Nobody ever got fired for buying Microsoft.” (The original version of this quote, referring to IBM, dates back to the 1970s). Nobody was ever handed a P45 for specifying the safe option.
And that’s precisely what an air knife is – safe, predictable and cost-effective.
An in-depth guide to air knives and air knife technology
2. Air Knives Have No External Moving Parts
Unlike other production line machinery, air knives have no outer moving parts that could trap or injure fingers or hands. The blower’s rotating impeller that creates the air pressure is tucked away safely inside the air knife housing. You’d have to take the machine apart to get to it.
And in some systems, the air blower may not even be in the same room as the plenum (blade) that delivers the airflow. So either way, the impeller is well away from the air knife operator or anyone else in the vicinity.
That’s no reason to be complacent though. At ACI, we take air knife performance and safety very seriously so we’re always looking for new ways to minimise noise and displacement of water or debris (such as breadcrumbs during a food coating process).
Air knife systems such as our premium LNL are fully enclosed to reduce noise levels. There are noise attenuation guards around the EP10A blower, and baffle plates on both the entry and exit points.
Ninety per cent of our air knives are used to remove moisture in applications such as food processing, packaging/labelling, plastics/rubber and metal processing.
So the LNL’s robust stainless steel enclosure stops blown moisture from causing contamination elsewhere. The base is tapered for drainage purposes, and the stainless steel legs are adjustable too.
3. Low-Pressure Air Is Neither Too Hot Nor Too Cold
Air that is pressurised quickly heats up – and conversely, air that is suddenly depressurised then cools rapidly. In thermodynamics, this is called adiabatic cooling. It explains why the airflow discharged from a compressed air nozzle feels very cold…unpleasantly so.
As you have read, air knives operate at low pressure. So the air inside the blower is not heated up as much as the air inside a compressor. (This is another safety advantage in favour of air knives.)
Consequently, the low-pressure airflow from an air knife plenum is not as cold as compressed air. This is significant – not just for safety – but also because very cold air may not be suitable for your application. This is an important consideration for sectors such as food processing and aerospace.
Air discharged from an air knife blade will be around 30-40°C. That’s about the temperature of bath water.
Air temperature (and how it is affected by altitude) is one of the many factors we consider when creating a customised air delivery solution to suit your exact requirements.
4. Air Knives Have No Sharp Edges
An air knife delivers a clean and even blade of air – true laminar airflow with no turbulence. This maximises performance and cost-efficiency: there are no wasteful high spots and no underperforming low spots in the smooth carpet of air.
An air knife blasts away moisture quickly and efficiently with no fuss. But it doesn’t cut like, for example, a CNC machining tool. So in this context, the term ‘knife’ can be a bit of a misnomer.
An air knife has no sharp edges. Not on the plenum (blade) nor on the housing. ACI air knives are also designed with no nooks and crannies to ensure they’re easy to keep clean and sterile for industries such as food processing. (Find out more here about our air delivery solutions for the food industry.)
Air knives are a good, safe and dependable piece of equipment to have on your production line. On the other hand, compressed air systems pose the risk of hoses lashing around under high pressure if they become detached. Furthermore, hoses left lying around can also be trip hazards.
5. Will Air Discharged From An Air Knife Cut Me?
This is a question that we get asked from time to time. Given the ‘knife’ element of the product’s name, it’s understandable.
No – we’re pleased to confirm that you won’t cut your hand if it passes through the airflow discharged from an air knife. The air pressure is reassuringly low and safe.
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