Alderdice Differential Heads are used between a tee piece and the top of a windmill.
A Differential Head allows water to be pumped higher than the windmill and prevents water discharge from the top of the windmill column
Alderdice Differential Heads are made in two sizes, 1 3/8" (35mm) internal diameter and 1 3/4" (44mm) internal diameter, the barrels are made from 3.3mm thick brass tubing.
The 1 3/8" I.D. Differential Head has a 1 1/4" B.S. Pipe thread cut on both ends of the barrel. The plunger has three leather cup buckets, the rod is 5/8" W. caps are available screwed 1 1/4" B.S.P. or 1 1/2" B.S.P.
The 1 3/4" I.D. Differential Head has a three leather cup bucket plunger, with 5/8" W. rod. It is fitted with one cap (single end) or two caps (double end), screwed 1 1/4" B.S.P. or 1 1/2" B.S.P. or 2" B.S.P.
Strokes: 8" (200mm) & 12" (300mm) - Longer to order.