If I had to guess then I would say that most of us
probably haven't given a great deal of thought to the inner workings of compressors have we? I mean
what even is a compressor and why am I taking up any of your valuable time talking about them?
Exactly! Well, this is a very simple example of a compressor and what I'm demonstrating now is
perhaps one of the stupidest things you can do with a.. OW! Thankfully history is littered with
people much smarter than me who understand the far more useful potential that these sorts of devices
hold, not just for pushing air into bicycle tyres, which is of course what this thing's really
designed for, but a multitude of applications ranging from basic pumps to sophisticated
air conditioning systems and all sorts of other devices that have become the indispensable
drivers of our modern society. They all need a power source though of course. We wouldn't get
much done if we relied on hand-powered devices like this to keep our homes cool for example. And
it's a lot of power. The Carbon Trust recently calculated that air compressors of one form or
another account for more than 10 percent of total industrial energy consumption. And a lot of that
energy is wasted in leakages and heat generation, so finding ways to make compressors work
better is definitely a very good idea, not just to save money during the current
global energy crisis, but perhaps more importantly in the long term to reduce the
amount of energy we use in the first place. And now there's a new compressor design
on the market that's not just potentially revolutionary but actually literally
revolutionary. Let me show you what I mean. Hello and welcome to Just Have a Think.
It's easy to think of compressors as being a fairly modern invention but in fact they
date back to at least 1588 when an Italian engineer called Augustino Ramelli came up with
what we now would call a positive displacement compressor which he intended to be used
to pump water up from underground wells. In 1860 Ramelli's design was significantly
improved by two American brothers with the fantastic names of Francis Marion
Roots and Philander Higley Roots. Their device caught the eye of the superintendent
of a local iron foundry who realized that he could use it to blast air into his furnaces much
more efficiently than his existing bellows. The Roots brothers were smart enough to patent
their design and within 10 years they'd built a monster, 48-ton version of their Roots Blower with
enough power to shove a train carrying 22 people through a tunnel. So, you know, eat your heart out
hyperloop! These guys had nailed it 160 years ago! And just to conform to nationalistic stereotyping,
it took a German engineer to optimize the design. His name was Heinrich Krieger and in
1878 he twisted the blades of The Roots Blower to produce a design that he successfully
patented as the Schraubengeblase or screw blower. Then in 1935 a Swedish inventor by the
name of Alf Lysholm took the concept A step further with his twin screw supercharger
which led to the development of the Lysholm Compressor design that's still widely used in
all sorts of industrial applications today. One of the challenges faced by all compressor
designs is leakage. Most designs rely on extremely accurate machining to achieve very fine
tolerances between the compressing elements and the chamber that houses them. It's what's
known in the business as a 'Clearance Gap'. A gap is essential to avoid inefficiencies from
friction and costly maintenance from wear and tear but you want that gap to be as small as possible
so that only a very tiny amount of fluid is lost. We'll come back to that challenge in a moment,
but what about this new compressor design that I mentioned earlier on? Well it's called the
Lontra Blade Compressor and it's manufactured here in the UK by a company that is unsurprisingly
called LONTRA. To understand how it works I caught up with the company's CEO Steve Lindsey via
Zoom recently. Steve explained that the basic principle of the design is essentially just my old
bicycle pump bent round into a circle and he was kind enough to lend me this scaled down model
to help show the inner workings of the device. Inside this sealed metal chamber there are
two elements rotating perpendicular to each other. The vertically rotating element has a
blade attached to it that draws in a parcel of air via a large permanently open inlet at the
bottom of the chamber. As the blade continues to rotate air fills up the entire chamber until the
blade reaches this point. So that's pretty much exactly what happens as I pull open the handle
of my bicycle pump. I've now got a full chamber of air in here. Now, here's where we get some
clever geometry going on. As the blade reaches the top point it's able to pass through this very
precisely engineered slot in the perpendicular rotating disc. But crucially, because the shape
of the blade is such that it slides very snugly through the slot, the air that's been drawn
in behind it is not able to pass through, so it's now captured in the chamber. Because the
unit is in perpetually rotating motion the blade now sweeps back around the lower half of the
circle where it does two things - it draws more air in behind it via the large lower intake port
and it squeezes the air that it captured during the previous revolution, which is precisely what
happens as I push the handle of my bicycle pump back down again. And just like in a bicycle pump,
that squeezed air is now at a nice high pressure. You'll notice there are some holes drilled into
the wall of the rotating chamber. Those holes are sealed in by the outer wall until they reach
this part of the rotation where they meet a large external opening through which the compressed
air is able to escape. Again the basic principle is not dissimilar to my bicycle pump. In my
case the pump puts air into my bicycle tyres and in the case of the Lontra blade compressor it
provides compressed air for whatever application it's bolted onto. And that's really all there
is to this beautifully simple design. The two perpendicular rotating components are mechanically
linked through a gearing system so that once everything's been correctly calibrated to ensure
the blade arrives at the slot at precisely the right moment it will always arrive at that point,
at that moment, in all subsequent revolutions. There's no back and forth motion like you're
getting a reciprocating piston setup which means there's very little wear and tear to worry about
during the operational lifetime of the compressor. An ideal pump or compressor or piston would have a
very long stroke or distance of travel but with a very small diameter in order to minimize leakage,
which brings us nicely back to that clearance gap I mentioned earlier. The trouble is if you make
the piston and rods very slender and long you tend to get all sorts of wobbliness going on
that can quite quickly lead to poor tolerances and breakage. Because the Lontra compressor is
essentially a bicycle pump wrapped around into a circle it allows you to have that highly desirable
very long stroke but without the wobbliness because all the forces are constantly being
translated around the circle which as I'm sure you know is one of nature's strongest geometric
shapes. Now of course there is existing technology like rotary compressors and screw compressors that
are engineered to partially overcome the leakage problem and they're in use in their millions all
over the planet for myriad different applications. But all of them rely on a clearance gap that
only reaches its tightest point at a very narrow intersection at the very apex of a fin or lobe.
You can see that on either side of the apex the gap drops quickly away and widens significantly.
So that means you have to have extremely tight tolerances at that very small point where
you're actually achieving a seal which makes that part of existing compressors a relatively
expensive component to manufacture. By contrast the geometry of the Lontra blade compressor means
that the radius at the edge of the rotating disc is concentric to the housing that it's rotating
within. That means there's a much wider surface area for the clearance gap to seal against, which
in turn means you get a much better seal with a much less expensive piece of machining. That
might sound like a bit of a pedantic detail but it makes a massive difference to the overall
efficiency of the compressor. Lontra's technology has already achieved energy savings of 21%
at a Severn-Trent water treatment facility where it performs the crucial function of water
aeration. Even greater efficiency improvements of around 34 percent have been achieved in industrial
pneumatic conveying applications, by which I mean blowing commodities through a network of pipes
in a factory. All sorts of products from pasta and beans to confectionery and powders and even
pharmaceutical tablets are all far more easily transported around a production facility inside
enclosed plastic or metal tubes then they would be via a conveyor belt. Imagine trying to convince
all your dried cannelloni to go around a corner without falling off the belt! Nightmare! If you
can chuck it all in a plastic or metal tube and blow it around using compressed air instead then
you've got yourself zero wastage and a much more sterile and hygienic environment to boot. And
of course the Lontra system is not limited just to those applications either. There are countless
different scenarios where the efficiency of their compressor geometry would offer very significant
savings. According to Our World in Data, energy use in industry represents more than 24
percent of global anthropogenic CO2 emissions, and we established earlier that compressed air
accounts for about 10 percent of that energy use. So if efficiency improvements of 34% could
be achieved in all industrial compressed air applications then just that one measure alone
could potentially reduce overall carbon dioxide equivalent emissions by more than 400 million
tons every year. Food for thought isn't it? No doubt you've got your own views on the subject
and you may even be working in the development of technologies like this and therefore have
some useful insights that you could share. If you do then why not jump down to the comments
section below and leave your thoughts there. That's it for this week though. A huge thank
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