Sealing system for a rotary expander

A sealing system for a rotary expander is described. In this machine, the work chamber is bound by four identical rotors and two side plates. The rotors turn at the same speed and in the same direction. Each rotor requires two apex seals and two side seals. Configurations for the apex and side seals were arrived at on the basis of the particular requirements of the engine, not encountered in other types of rotary engines. The apex seals come in contact with one another at certain points and a smooth passage past each other is required. The side seals run along the edge of the rotors rather than some distance in. Apex and side seals of novel design were built and subjected to preliminary testing in the engine operating with compressed air. No significant problems were encountered. The performance of the sealing system appears to be satisfactory in the case of seals made out of lead bronze. Carbon filled PTFE seals are to be tested in the next phase of the development program.