Solar actuated siphon drain

A solar actuated siphon for transferring liquid from an upper level to a lower level, said siphon having an inlet for immersion in said liquid at said upper level and an outlet at said lower level, an enclosed container having a chamber in communication with said siphon, first valve means between said siphon and said chamber, said first valve means being responsive to open when gaseous fluid pressure in said chamber is less than the fluid pressure in said siphon and to close when the fluid pressure in said chamber is greater than the fluid pressure in said siphon, second valve means between said chamber and the space at atmospheric pressure outside said container, said second valve means being responsive to open when the gaseous fluid pressure in said chamber is greater than atmospheric pressure by a predetermined amount and to close at lower fluid pressures, a third valve means at said outlet being responsive to open when the fluid pressure in said siphon exceeds atmospheric pressure by a predetermined amount and to close at lower fluid pressure, means associated with said chamber for absorbing radiant solar energy to heat and thereby increase the pressure of gaseous fluid within said chamber, said second valve means being responsive to the increased pressure of said gaseous fluid to permit ejection of a portion of said gaseous fluid from said chamber, and said first valve means being responsive to a reduction in pressure of the remaining portion of gaseous fluid within said chamber on cooling causing said first valve means to open and communicate the resulting subatmospheric pressure in said chamber to said siphon, said third valve means maintaining a closed outlet and said subatmospheric pressure being communicated to said siphon and said inlet causing said liquid from said upper level to flow into said siphon and towards said outlet, said third valve means opening upon filling of said siphon with said liquid whereby said liquid is transferred from said upper level to said lower level.