What on earth is this? [SOLVED: Victorian drainage interceptor trap plunge shaft]

[edwardian1913]

Can anyone explain what this ceramic inlet/outlet is?

Unknown-thingy

• edwardian1913
• 7 Aug 2015

Unknown-thingy-2

• edwardian1913
• 7 Aug 2015

Top is about 9" in diameter and leads to series of vertical ceramic pipes. It is located about 11 feet from the pavement appears to be connected to the waste water (when I empty the bath you can hear rushing water and faintly see rippling water at the bottom. Haven't measured the depth of pipe but I would say around 12-18 feet. Property is late Victorian.

So can anyone tell me what this is called and what it's used for?

 

[Burnerman]

Its a plunge point for a water trap that's beneath it.......a sort of an interceptor trap design.
Google interceptor traps and you'll see what I mean.
John

 

[JimCrow]

a disconnecting trap.

 

[Burnerman]

Is that the same thing, Jim?
John

 

[edwardian1913]

Thanks for the quick responses

Wikipedia (so it must be true(!)) suggests that interceptor traps, disconnecting traps and Buchan traps are alternative names for the same thing.

https://en.wikipedia.org/wiki/Buchan_trap

Apparently the Victorians thought cholera was an airborne - not waterborne - disease, so these traps were designed to prevent sewer air entering the house via the waste water pipe.

In my specific case I think it's a stand alone interceptor trap "commonly found before the drainage system crosses a boundary line". Apparently we are lucky the plunge shaft is still accessible:

"i have optimistically shown the plunge shaft rising up to surface level though in reality this is seldom the case with gardeners, landscapers and drive layers burying or concealing the access shaft."​

http://www.draindomain.com/interceptor traps.html

Thanks again for solving our front garden mystery!

 

[Agile]

Here is the supplier's drawing.

http://www.knowlesdrainage.co.uk/pr...oryID=12&subcategoryID=20&parentproductID=730

You are very lucky to have one available in case the trap becomes blocked.

The only problem is finding an adequately flexible rod to use for cleaning them. I cannot think of any!

May need pressure jetting.

Although a sudden discharge of bulk water may well be easier and quite effective.