The Bishop Steam-to-Vacuum Engine received U. S. Patent Nos. 6,951,107 in 2005 and 7,194,861 in 2007. The latter patent covers an engine with three, four, or more cylinders/pistons
The STV Engine is available for exclusive or non-exclusive license to qualified partners interested in developing it for manufacture and distribution.
Serious companies please contact Lloyd Bishop for more information.