摘要 |
<p>A water control apparatus is disclosed which is automatically turned on and off responsive to the moisture content of a moisture sensing element which is placed in the locale where it is desired to control the flow of water, such as in the ground or above a pool or as a humidifer. The device does not require any electical power supply, and uses a venturi device and a ceramic moisture sensing element that is porous to air when dry and impervious to air when wet to control a pressure sensitive valve.</p> |