In a steam engine, an intermediate phase is provided for preheating the feedwater before it enters the boiler. The preheating is achieved by means of the reapplication of the otherwise dispensable exhaust steam in a simple feedback operation in which the exhaust steam is introduced directly into the feedwater. By means of electronic controls the operation of the system at the highest possible point of preheat (up to 210.degree. F.) is achieved thus assuring both high efficiency of the machine and cumulative economy in fuel consumption as well. The latter is further augmented by generous application of insulation to prevent wasteful dissipation of thermal energy as well as to effect protection of the system against the elements.
REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of application Ser. No. 596,601 filed July 17, 1975 now abandoned entitled "HIGH EFFICIENCY STEAM ENGINE PEGASUS I".
SUMMARY OF THE INVENTION
In accordance with the present invention a special low pressure feedwater tank is provided surrounding the boiler of the steam engine. Whenever the temperature of the feedwater is below a predetermined minimum, the exhaust steam from the boiler is introduced directly into the bottom of the feedwater tank to preheat the feedwater up to just below boiling. The exhaust steam from the boiler is introduced into the feedwater by means of a pipe coiled around the bottom of the feedwater tank in several turns and provided with apertures through which the exhaust steam is allowed to bubble into the feedwater tank. When the feedwater has been heated to a temperature just below boiling, the exhaust steam is released into the atmosphere bypassing the feedwater tank. The fuel to the burner for the boiler and the position of the burner relative to the boiler is controlled automatically in response to boiler pressure which changes with the fluctuations in the level of workload demand.
The steam engine, thus, is of simple construction that achieves high efficiency and an economy in fuel consumption as well as minimum environmental pollution and operating noise with full safety of operation.
A temperature-difference-actuated pump is disclosed which does not require the use of electrically operated solenoid valves or the like, making the inventive pump especially useful in locations where electricity is not readily available. Either one or two pump chambers is provided, in which is disposed a pumping element such as a flexible bag or piston. One side of each chamber is connected selectively to a boiler or condenser through a mechanically operated switch deriving its working power from the pumping element. The other side of the chamber is utilized to provide the pumping action, either directly or via a noncondensable fluid.
A hot water boiler having a dual combustion chamber arrangement capable of burning either solid or fluid fuels, and arranged for acting directly on a heat transfer system generally in direct contact with firebox walls of the combustion chamber arrangement. Disposed atop the combustion chamber arrangement is a heat conserving flue assembly which absorbs heat from smoke and flue gases exhausted from the combustion chamber arrangement and heats a fluid medium which in turn is circulated to the heat transfer means for eventual release for circulation or storage as desired in a residence or other building structure. The heat transfer system includes a fluid containing cavity divided into two parts by a suitable membrane, with pipes being provided penetrating the membrane for permitting transfer of the fluid medium from one part of the cavity to the other, with the heat transfer fluid medium thus being initially heated in the flue assembly, transferred to a first, or uppermost, part of the cavity of the heat transfer system, and subsequently transferred to the lower part of the heat transfer system and discharged entirely from the boiler structure.
A fuel-fired commercial water heater has upper and lower communicated tank portions which are separated by a plenum forming a vertically intermediate portion of a dual pass condensing type heat exchanger. A lower portion of the heat exchanger is defined by a series of vertical flue tubes extending through the lower tank and intercommunicating the plenum with a combustion chamber disposed beneath the lower tank and having a fuel burner with a discharge portion communicated therewith. An upper portion of the heat exchanger is defined by a vertical flue pipe, disposed in the upper tank, that extends upwardly from the plenum and then coils downwardly around itself and horizontally exits the upper tank. During firing of water heater the burner flows flue gases sequentially through the lower tank flue tubes, the plenum, and the upper tank coiled flue pipe structure.
An energy recovery system for wheeled vehicles is characterized by a compressor/expander which operates as an expander in the run mode to assist the engine in driving the vehcile and as a compressor in the braking mode to store braking energy. A heat exchanger, a boiler drum, and a flash chamber transfer heat from the vehicle exhaust to a working fluid for generating high and low pressure vapor. The boiler drum stores heated and vaporized liquid and supplies high-pressure vapor to the inlet port of the compressor/expander during the run mode. The flash chamber supplies low-pressure steam to the inlet port of the compressor/expander during the braking mode. Storage tanks are provided for storing and passing low-pressure vapor to the input of the compressor/expander during the run mode.
