Apparatus for automatically regulating water level in a swimming pool

An automatic control system for use in a swimming pool system including a pool having a pool inlet located at a lower level than a predetermined desired pool water level, a pool outlet, and a recirculation system for circulating pool water from the pool outlet to the pool inlet including a motor-driven pump having timing means for turning the motor on and off periodically, filter means for cleaning the recirculated water, and conduit means including a return conduit connected between said filter means and said pool inlet and a pressure of fresh water, for detecting, during periods when the pump is turned off, when the level of the water in the pool is below said predetermined desired level and for adding fresh water to the pool in response to the detected level for automatically restoring the pool water to said predetermined desired level, said automatic control system comprising:

• a vertically elongated cylindrical vessel having closed upper and lower ends and adapted to be disposed in close proximity with said return conduit at least partially below the water level in said pool;
• means for operatively coupling said vessel to said return conduit at a level below said predetermined desired level for allowing swimming pool water under sub-water level pressure to enter said vessel and rise to a level corresponding to the pool water level when said pump is not operating and for allowing water in the return conduit to enter said vessel and rise to a level above the pool water level for isolating said vessel from said pool whenever said pump is operating;
• normally closed valve means supported within said vessel having an inlet connected to pipe means extending from near the lower end of said vessel and adapted for connection to the source of fresh water under pressure, said valve means including first float means for monitoring the water level in said vessel as a measure of water level in said swimming pool, said valve means adapted to be opened to allow water to start flowing from the source immediately following cessation of operation of said pump by said first float means dropping in response to water being drawn from said vessel by a partial vacuum created by the rush to the pool inlet of water in said return conduit and to remain open so long as said first float means is below a level indicative of said predetermined desired level to allow water to continue to flow from the source into and out of said vessel, into said return conduit and then into said the pool, and to close and terminate flow of water from the source in response to said first float means rising to-a level indicative of said predetermined desired level;
• and
• normally open float-actuated valve means mounted inside the closed upper end of said vessel for venting said vessel to atmosphere whenever said pump is not operating and adapted to be closed, whenever said pump is operating, in response to the float thereof sensing that the level of water within said vessel has risen to a level higher by a predetermined amount than said predetermined desired level for isolating said vessel from said pool.