Solar powered liquid metering device

Claim 1

A solar powered liquid metering device comprising: a unitary container including: a solar chamber sealed from atmospheric pressure, said solar chamber containing a quantity of a liquid to be pumped in a lower portion thereof and an expansible gas filling the remaining volume thereof, said solar chamber having at least one wall adapted to be exposed to direct solar radiation, and an overflow chamber open to atmospheric pressure and also containing a quantity of said liquid, said solar chamber and said overflow chamber being separated by a wall having an opening at a lower end thereof to allow fluid communication between said liquid within said solar chamber and said liquid within said overflow chamber; and an overflow outlet opening within said overflow chamber for draining excess liquid from said overflow chamber that is above a predetermined level, filler means coupling a supply of said liquid to said overflow chamber and operative to permit liquid to flow from said supply into said overflow chamber when said liquid level within said overflow chamber is below said predetermined level, and valve means permitting a preselection of the amount of liquid metered out during an operating cycle by allowing the amount of gas within said solar chamber to be varied prior to the commencement of said operating cycle by opening said valve means and introducing or removing gas from said solar chamber, said valve means being normally closed during said operating cycle.