In the early part of the 1900s 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 ......In the early part of the 1900s 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 1930s. Developed in the past, proven throughout the present and custom engineered for the future.