Abstract: An automatic liquid delivery apparatus which employs no moving parts and requires no external source of energy except gravity to operate, dispenses liquid from a constantly available source, which is open to the atmosphere, to a receiver or zone requiring liquid in response to a detector which is located in the zone and initiates discharge of the liquid. The apparatus includes a valve device which retains liquid against discharge from a container or supply by air pressure confined in a space in a passage. The valve device delivers liquid through the passage when air in the space is released by a control device. The control device is a detecting mechanism or other automatic operating element. The detecting mechanism can sense the moisture level in soil, in liquid, in roots growing in moist air, in plant tissues or any other location where moisture differentials can be detected.

Abstract: An automatic liquid delivery apparatus dispenses liquid from a liquid container or other liquid supply to a receiver or zone requiring liquid in response to a detector which is located in the zone and initiates discharge of the liquid. The liquid is retained against discharge from the container or supply by air pressure in a liquid passage and is discharged upon release of the air through the detector, when liquid is needed in the receiver or zone.The automatic liquid delivery apparatus in a liquid feeding system may be used to supply liquid to growing plants; a detector for each plant or group of plants initiates the dispensing of liquid by a delivery apparatus, each detector sensing the moisture requirements of a particular plant.