In the early part of the 1900's the "shuttle block" rotary piston pump was invented. Tri-Rotor, Inc. has been manufacturing "Tri-Rotor" pumps and parts to exacting standards ever since. Improvements have been designed to be completely interchangeable with original pumps, allowing us the ability to replace or retro-fit even the oldest pumps from "in-stock" parts or with minor modifications. Pump records, by serial number, are on file as far back as the 1930's.