The present invention relates to pumps, and more particularly to a pump for two fluid media having different temperatures.
In view of the current energy shortage, various efforts are being made to convert into mechanical energy either solar energy or heat which itself is produced as an inevitable concomitant of a fuel-consuming process. One way of doing this would be to provide a cylinder which is filled with a fluid and within which there is a piston which is pushed out of the cylinder under the pressure of the fluid, this fluid being exposed periodically to solar radiation. The piston acts on an eccentric which is mounted on a shaft, and the fluid is then pivoted so as to be exposed to a cold water reservoir whereupon the piston is returned into the cylinder. Such a solar engine is hardly practicable, considering the relatively large amount of energy it takes to run the parts of the engine itself. It is apparent, therefore, that if heat energy derived from the sun is to be converted into mechanical energy, one has to move away from conventional concepts of engine design.
The present invention, therefore, relates to the special problems incident to the development of a pump which can be operated by heat energy, and particularly by heat energy derived from the sun. The problem is thus closely related to the field of solar radiation collectors, inasmuch as such collectors normally operate using a circulating fluid medium, particularly water, in which cold medium is fed to the collector, this cold water being heated up and then moved to a warm water reservoir, as, for example, a swimming pool. In practice, the fluid is normally circulated by means of a pump, and in conventional systems, this pump is powered by externally generated electrical energy. It will readily be appreciated that it would be advantageous if the pump could be driven by energy derived from the heat energy which is obtained from the solar radiation, that is to say, if the pump could be operated without being dependent on energy derived from burning fossil fuels. Conventional solar energy collectors operate with relatively high efficiency, and the overall operation of these systems would not be adversely influenced if part of the heat energy derived from the collector were used to energize the pump which circulates the fluid medium through the system.
In practice, of course, a pump which is actuated without requiring any heat other than that which is brought in by the medium flowing through the pump, can be used for many other purposes. One example of this would be to use the pump for pumping water from a well into an above-ground storage tank.
It is, therefore, a primary object of the present invention to provide a pump which is energized solely by heat, and more particularly, a pump which is energized by two fluid media which are at different temperatures.