Some years ago I came into the possession of a Roberts Duplex Water Motor. Information on these is a bit sketchy. This is what I've either found or have been told. They were not manufactured for very long, about 1890 -1912. The earliest patent I found on Google patents is dated 1902 and it was an improvement to existing designs. The resemblance to a duplex boiler feed pump is unmistakable
These machines were powered by municipal water which at the time was of poor quality. So they were used to pump well or rain water to buildings. This water was used for laundry and cooking. Gradually water quality improved and so these machines were no longer needed.
This machine is in very good condition with its original paint. I believe it dates before about 1910. This is based upon the fasteners used on the cylinder heads and what would be called the steam chests if this were so powered. They are #14 -20 threads with a major diameter of 0.236". Later around 1910, the Unified Thread system was introduced and this fastener became the 1/4" - 20 NC thread. The hex head screws seen in the photo have since been replaced by cheesehead screws that I made from brass stock.
The leather wrapped bronze pistons had disintegrated on both the pump and power sides and various fasteners were missing. The piston rods (brass) were worn.
I decided to make new bronze pistons with stainless steel piston rods as a temporary measure to see whether the cylinders on both sides were still providing a good seal. I have powered the machine so far on compressed air and it works smoothly. You can view a video of it here:
I would welcome any additional information about these machines. Were similar machines found outside the USA?
Cheers,
Phil
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