Toto Drake Bowl Discharge Outlet

[georg]

The bowl is the C744E 01. The outlet I am referring to is the one at the bottom of the bowl, over which the wax ring fits. This outlet is only visible when the bowl is turned upside down, before installation.

There is a very pronounced ridge at the outlet. The outlet itself is 2 1/8 in dia but the trapway a 1/2 in upstream is about 2 1/2 in dia. Seems to me that this ridge could snag a long thin object, like a lipstick pencil, of the right length. Does anyone know the purpose of this ridge?

 

[WJcandee]

Are you planning to flush a lipstick pencil?

This design has been around for a long time, now, and as a proud Toto Drake owner I can tell you the thing flushes like a dream. Whatever you think might happen does in fact not happen in ordinary usage.

That said, foreign objects do get caught at the outflow of many toilets. Terry has a great photo of a GI Joe that he found in the outlet of another brand toilet when he pulled it because the owner said it had stopped flushing properly.

 

[Sponsor]

 

[georg]

Are you planning to flush a lipstick pencil?

This design has been around for a long time, now, and as a proud Toto Drake owner I can tell you the thing flushes like a dream. Whatever you think might happen does in fact not happen in ordinary usage.

That said, foreign objects do get caught at the outflow of many toilets. Terry has a great photo of a GI Joe that he found in the outlet of another brand toilet when he pulled it because the owner said it had stopped flushing properly.

 

[georg]

This is the discharge of the lowly Toto Carusoe. Notice the smooth throat, unlikely to snag any errant objects.

Objects like pill bottles end up in the toilet, sometimes by accident. Someone flushes the toilet and then retrieves a bottle from one of those storage units that straddle a toilet, drops the bottle by accident and it gets flushed into the toilet. Restaurants have to deal with unhappy customers deliberately trying to clog toilets by throwing in foreign objects. A smooth throat makes it more likely that the objects pass through and not get caught.

 

[WJcandee]

The Carusoe is the one Toto I wouldn't buy. It's as close to a builder-grade toilet as they make. The design of the Drake is far superior, the flush is far superior, etc., etc. The Drake (and subsequent Totos) have a double-siphon setup. It was the ingenious, patented thing that put Toto in the lead for low-flow flush quality for probably 10 years, and allowed a much-smaller amount of water to actually evacuate the bowl, something that most other brands' original 1.6's didn't do well. Perhaps the double-siphon chamber is the reason that there isn't just a smooth passage from weir to outlet.

 

[georg]

Never heard of the double siphon, so I googled Toto Double Siphon and only came up with Double Cyclone.

 

[WJcandee]

Toto doesn't talk about it much, actually. It's also called a dual siphon. In any event, some engineer explained it on this forum a couple of years ago.
wjcandee


I am a civil engineer (water, sewer, flooding, paving). At my office the landlord recently installed a Toto toilet, and I am effusive about it! I don't know which model it is, but it is amazing, and in inspecting it, I can see it has a double siphon below the bowl. The only thing I can't understand is why there aren't more double siphon toilets around, unless Toto has a patent on the double-siphon concept.

Let me explain briefly why the Toto is so simply amazing. Most toilets have a single siphon below the bowl that gets started when you dump water into the bowl (by flushing it the normal way or with a bucket) and then stops when the siphon gets broken either 1) by running out of water in the bowl and letting some air in the top (making that end-of-flush gurgle) or (and this is the catch) 2) by slowing down to the point that water dribbles away and lets air enter from the sewer and break the siphon. But Toto toilets have a second siphon near the floor that doesn't let the first siphon break until the flush is done and water runs out in the bowl. This forms what Toto calls a Power Gravity Flush. You get the vacuum effect of the entire height from the bowl down to the floor pulling the water and solids out of the bowl. Very ingenious. I've sketched it below.

Tom Haws, P.E.
HUBBARD ENGINEERING
Civil Engineers and Land Surveyors

 

[georg]

Thanks for the explanation, that makes sense. I did notice the hump in the bottom horizontal run of the trapway. It does cause one minor annoyance when removing a Toto. I usually use my wet vac to suck all the water out of the bowl before lifting it off so that no water spills on to the floor. But that hump traps a little water in the trapway and spills on to the floor when the toilet is lifted off.

My motive for my original post was to see if I somehow ended up with an inferior Toto, whether an unauthorised clone or a genuine Toto but of lesser quality due to a poorer design. It had all the stamps and markings of a Toto. I just fail to understand why it does not have a smooth throat. I did buy this Drake online C744E-01

If anyone has a spare Toto Drake C744E bowl lying around, would you please check the throat to see if it is smooth?