Page 132 - How It Works - Book Of Amazing Answers To Curious Questions, Volume 05-15

How do aircraft toilets

work? The powerful vacuum system that fl ushes

your waste at 30,000 feet

he incredibly loud and powerful Vacuum toilet tech 2. Flush
suction of aircraft toilets might When the toilet is

Tmake you jump when you press the What happens to your flushed, a valve
underneath opens
‘flush’ button, but it is there for a good waste when you go to and the vacuum in

reason. The conventional toilet you are the loo in the sky? the pipes sucks the
familiar with wouldn’t be practical on a 3. Sanitising liquid waste out.
moving jet as the toilet bowl full of water At the same time, a small
would be likely to spill during turbulence. amount of blue sanitising
liquid is deposited into the
As this water, with the help of gravity, is toilet bowl to clean it.
required to flush out the waste, another

system had to be developed to empty the 4. Waste tank
bowl more effectively. The waste and
Until 1982, electric pumps were used to sanitising liquid are
send a blue sanitising liquid into the toilet sucked into the waste 1. Vacuum
bowl with every flush and push out the tank and remain generator

A pump draws the air
there for the duration
waste. However, this required hundreds of the fl ight. out of the pipes and the
of gallons of the stuff to be carried on waste tank to create a
every flight, taking up lots of weight and vacuum effect.

space. Nowadays, most aircraft use
vacuum toilets, which only use very small
quantities of sanitising liquid for the
purpose of cleaning the bowl. The waste is
removed using powerful suction created 6. Rinse line 5. Drain valve
by a vacuum in the pipes, but don’t worry, Another pipe accessible When on the ground, a
unless you are able to perfectly seal the from the outside of the drain valve on the outside
aircraft allows water to be
of the aircraft is opened
bowl with your backside, you won’t get pumped into the waste and the waste is vacuumed
stuck to the seat! tank to rinse it out. out of the tank.
Directional speakers Headrest
These micro-speakers are The all-important directional How will car audio
perfectly positioned near to speakers are planted just
the occupant’s ears for beneath the cushioned
maximum audio effi ciency. surface here, optimising
sound while not technology evolve?
Amplifier compromising safety.
This increases the
amplitude of electric Listen to music in your own personal
signals for each of the
circuits, with usually
one per personal sound zone
sound zone.
ver had to endure a car journey standard car audio speakers and
with nothing but the tedious headrest speakers to the desired
Eresonance of your parents’ frequency of the occupant, providing
favourite music for company? Thanks cross-talk cancellation (CTC) against
to cutting-edge technology currently other sounds.
Aside from being able to listen to
being piloted in the automotive your own music, this breakthrough in
industry, passengers of the future
© REX/Darek Siusta/Solent News; Harman Woofers passenger’s audio experience music thanks to personal sound benefits to the occupants of any
audio technology presents a host of
could be able to listen to their own

vehicle. For example, with the sound
zones. The technology works by
Electrodynamic
placing more small yet powerful
zones, any navigation prompts to the
Planar Loudspeakers
driver will have little impact on the
micro-speakers in the headrest of a
seat, so the sound is nearer to the
audio experience of others, and
These EDPLs tune the
These amplify the low-
acoustics to ensure the
incoming calls can effectively be
head of each individual passenger
frequency bass for each
‘passed’ through the car to the

– but there’s more. A filter matrix then
is optimised for their location
personal sound zone, removing

a ‘tinny’ acoustic effect.
132 How It Works in the vehicle. modifies the wave field of the intended recipient.