Found during drainage work in a field near Eshott, Northumbria and donated to the cause by Kevin Monaghan.
These segments are slightly curved across their width and join together along their length by a tongue and groove method.
They form a complete circle.
The manufacturer is unknown.
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Below – Each section measures 13½” – 14″ long x 6½” wide x 2½” thick.
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It appears that different diameter drains can be formed depending on how many segments you fit in a ‘ring’. There seems to be enough play in the tongue and groove fittings to create multiple diameters.
I could not get any less than 8 segments in a ring as the internal edge of the T & G is ‘tight’ and butted up. 9, 10 and 11 seem to form together with no problem. I think 12 is easily achievable too as seen from a photo to follow. Each section has a slight curve running along its length so I think long bends are also easily achievable. 8 = 11½” internal diameter. 9 = 13″, 10 = 14½”, 11 = 16½”, 12 = 18½”.
Below – 8 = 11 1/2″ internal diameter
Below – 9 = 13″ internal diameter
Below -10 = 14½” internal diameter
Below – 11 = 16½” internal diameter
Below – 12 = 18½” internal diameter
Below – A similar segmented drain was photographed by Nick Savage, near Sampford Peverell, Devon.