Paper: RG Roto Jet Design A New Concept In High Pressure Pumps

The pitot pump first appeared in U.S. patent history at the turn of the century. The first forms were of the open ring rotor type which had many performance limitations. During the 1920"s, the basic closed rotor form was described in patents, such as shown in Fig. 1. This closed form was extensively studied in Germany in the years 1939 - 1945 (Ref. 1) for use in aircraft and rockets, and in Britain during the late 1940"s. Development on this pitot pump study was stopped when it was found the design did not lend itself to being extended to flows over 5 GPM. It was also determined by this group that the pump was prone to air-locking 2 and airbleeding methods were patented. 3, In 1959, a pitot pump study was completed and reported by the U.S. Office of Naval Research 4 in which a number of pitot pumps were built and tested. They also suggested additional research be carried out, although no research has been reported at this time. In this study, test efficiencies were reported of 25 - 30%, and head coefficient of 1.10. In 1962, development work was started in the United States that led to the enclosed rotor spin-up passages and other concepts that form the basis of the Roto-Jet form of pitot pump. These closed rotor passages and grooved spin-up slots result in efficiency increases of 5 to 10 points and are described by Patent Nos. 3,384,024 and 3,795,459. The special diffuser construction in the pitot tube increases the efficiency by 15 points. Another unique feature that has been developed is the ability to operate with very high inlet pressures, as the rotor can be completely pressure-balanced.