The STV engine utilizes the vacuum made when steam is cooled and expanded to condense to water droplets. Water in the Steam Boiler is heated to 230 degrees F. to make steam. Steam from the boiler fills a twin steam cylinder/piston on an intake-of-steam stroke. 1,700 units of steam condense down to 1 unit of water with the remaining space units in vacuum.
When steam has entered a cylinder, steam-to-vacuum occurs almost instantaneously. Steam rushes from the cylinder to expand and be cooled to condense to become vacuum. Vacuum now is present in the cylinder. When vacuum is in a cylinder, air pressure pushes a piston to fill the vacuum with a force of 14.7 psi. Air pressure can now push the piston end-to-end to fill the empty space in the cylinder with a power stroke force of about 400 lbs. Cylinder/pistons are connected so that a motion of one piston creates a similiar action on the twin piston.
Power strokes alternate at an average rate of 120/min. Connected piston rods are bolted to a power arm (P. A.) which is fastened to a power shaft (P. S.) which is attached to a crankshaft and a flywheel, or a power wheel, which transfers power to do work.
The rate of power strokes is determined by the speed of the condensation of steam to form the vacuum in the steam cylinders. Steam condenses instantaneously when it is cooled in the heat exchangers and exposed to low level vacuum. The condensers/heat exchangers are in two positions, vertical (H. E.V.) and horizontal (H. E. H.). The low level vacuum, 21" HG. in the Vacuum Tank, draws the steam out of the Steam Cylinders which leaves a vacuum there. The extra space, provided by the Extention Pipes (E. P.), allows the steam to expand and cool which assists in the condensation process.
The Auxiliary Vacuum Tank can function as the Vacuum Tank if it loses vacuum or overheats. The Vacuum Pump instills the initial vacuum in the tanks and the connecting pipes.
The Condensate Collector Tank receives condensate from the Vacuum Tank or the Center Drain Pipe. Condensate is pumped up to the Steam Boiler for reuse while still warm.