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readytotaxi
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The Vacuum Toilet,who And When Pls.

Wed Sep 29, 2010 3:36 pm

When was this toilet type first used on commercial aircraft and which aircraft had it first?
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Drfix2fly
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RE: The Vacuum Toilet,who And When Pls.

Wed Sep 29, 2010 7:40 pm

just guesing but the 767-200 is the oldest aircraft I have seen it on
 
Tod
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RE: The Vacuum Toilet,who And When Pls.

Thu Sep 30, 2010 8:41 pm

Quoting Drfix2fly (Reply 1):
just guesing but the 767-200 is the oldest aircraft I have seen it on

Correct

First flight 1981
 
babybus
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RE: The Vacuum Toilet,who And When Pls.

Sun Oct 03, 2010 1:28 pm

Does anyone know why you need a strong vacuum toilet flush system and not just a water and gravity system on an aircraft?
and with that..cabin crew, seats for landing please.
 
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glen
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RE: The Vacuum Toilet,who And When Pls.

Sun Oct 03, 2010 1:42 pm

Quoting babybus (Reply 3):
Does anyone know why you need a strong vacuum toilet flush system and not just a water and gravity system on an aircraft?

To save the weight of the additional water you would have to transport for a water flush system.
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HAWK21M
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RE: The Vacuum Toilet,who And When Pls.

Sun Oct 03, 2010 2:55 pm

Quoting GLEN (Reply 4):

To save the weight of the additional water you would have to transport for a water flush system.

A reduction in corrosion issues due leakage.
regds
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zanl188
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RE: The Vacuum Toilet,who And When Pls.

Sun Oct 03, 2010 3:20 pm

Quoting babybus (Reply 3):
Does anyone know why you need a strong vacuum toilet flush system and not just a water and gravity system on an aircraft?

Flexibility in lav placement.
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Mender
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RE: The Vacuum Toilet,who And When Pls.

Sun Oct 03, 2010 5:05 pm

As ZANL said plus, it removes the odour everytime you flush.
 
MD-90
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RE: The Vacuum Toilet,who And When Pls.

Sun Oct 03, 2010 6:06 pm

Quoting babybus (Reply 3):
Does anyone know why you need a strong vacuum toilet flush system and not just a water and gravity system on an aircraft?

Not only do you gain flexibility in the cabin but it also reduces the number of holding tanks which saves weight and is faster to service on the ground.
 
Mender
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RE: The Vacuum Toilet,who And When Pls.

Sun Oct 03, 2010 8:44 pm

Quoting babybus (Reply 3):
Does anyone know why you need a strong vacuum toilet flush system and not just a water and gravity system on an aircraft?

How would you get a gravity system to work if you are climbing or descending?

You need a good vacuum to draw solid matter the full length of the aircraft. (If the vacuum was weaker not all the waste would make its way to the tanks and over time would block the pipes)

Once the aircraft is at altitude they use cabin differential pressure . On the ground they use a vacuum pump.
 
FlyASAGuy2005
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RE: The Vacuum Toilet,who And When Pls.

Tue Oct 05, 2010 5:49 pm

From what I was told, it was ultimately due to weight. My instructor but himself through flight school working cabin service and lavs and he would always say "on the older planes you had to deal with the first class shit and coach shit. Belive me, there is no difference in smell"
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HAWK21M
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RE: The Vacuum Toilet,who And When Pls.

Thu Oct 07, 2010 11:44 am

Is the term Gravity System or Recirculating system?
regds
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AA737-823
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RE: The Vacuum Toilet,who And When Pls.

Thu Oct 21, 2010 9:52 am

Quoting HAWK21M (Reply 11):
Is the term Gravity System or Recirculating system?
regds

"Gravity system" is not an appropriate term.
Recirc might be, but I do know there were two design philosophies in the blue-water systems, the one we're used to, and the design employed by Lockheed on the L-1011. I forget all the details, but as I recall, blue juice was stored in one or two locations, and ducted to each lavatory on demand. Compared to the traditional setup, where you've got a tank of blue goo under each toilet seat.

Vacuum lavs are a tremendous improvement for a variety of reasons, not the least of which is RELIABILITY. Especially at altitude, the system is basically infallible, unless you get a toilet base valve that won't close, and then you're in trouble.
But other than that, you're counting on the outside air pressure doing all the work for you- and that's pretty reliable!

Not to mention, blue water pump impellers? Do you REALLY have any desire to work on those? Trust me- not pleasant.
 
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readytotaxi
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RE: The Vacuum Toilet,who And When Pls.

Fri Oct 22, 2010 4:54 pm

Quoting AA737-823 (Reply 12):

Okay, the toilet base valve won't close, what problems flow from that?
I guess the Lav is out of bounds, will it just keep sucking for the rest of the flight?
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Dalmd88
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RE: The Vacuum Toilet,who And When Pls.

Fri Oct 22, 2010 8:54 pm

Actually the biggest problem in my book is the valve will not open or a plugged tube. They both have the same school of brown trout. I would much rather change a valve that is stuck open.
 
Mender
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RE: The Vacuum Toilet,who And When Pls.

Sun Oct 24, 2010 5:11 pm

Quoting readytotaxi (Reply 13):
Okay, the toilet base valve won't close, what problems flow from that?
I guess the Lav is out of bounds, will it just keep sucking for the rest of the flight?

If the base valve is stuck open then you will not be able to generate a decent vacuum on that line. There are generally two main vacuum lines on the 767 so potentially half the toilets will be affected. Luckily I've managed to avoid working on the toilets on the 737NG but this might effect all of them!
 
VC-10
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RE: The Vacuum Toilet,who And When Pls.

Mon Oct 25, 2010 4:17 am

Quoting Mender (Reply 15):
If the base valve is stuck open then you will not be able to generate a decent vacuum on that line.

A more immediate problem is the noise in the cabin for the pax sitting around the affected lav. We ACARS the crew if that happens to wrap an orange in a blanket and place that in the bowl. The open valve is then plugged.

Other probs with Vac Lavs are blockages in the main line to the tanks. On our 747's there are some sharp bends in the pipes where thay go round the cargo door lift actuators. If pax have managed to put a nappy, a hand towl down the loo or the CC have put wine bottle corks and other stuff down there guess where all the stuff gets caught up. Then some lucky individual has to break down the pipes to find and extract the blockage

On the A340 system the main problem are the liquid level sensors in the tank. If they get contaminated by not being rinsed properly during toilet servicing they sense tank full, even though the tank may be empty, and shut down all the toilets that supply that tank. This problem can be overridden by pulling a few CB's, but it means if the toilet tank does subsequently become full the tank will overflow and you are left with skid marks on tail of ther aicraft where the vacuum outlets are
 
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readytotaxi
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RE: The Vacuum Toilet,who And When Pls.

Mon Oct 25, 2010 5:52 pm

Quoting vc-10 (Reply 16):

WOW, thanks for all the info, it really is a whole different world down there.
Just one flush and you think its all gone.  
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Tod
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RE: The Vacuum Toilet,who And When Pls.

Wed Oct 27, 2010 2:35 pm

Quoting vc-10 (Reply 16):
On our 747's there are some sharp bends in the pipes where thay go round the cargo door lift actuators.

Forward cargo door?
Retrofit lav/waste tube installation?
That area can be a pain, but it can be designed to function OK.
Not former SAA 744 are they?

Tod

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