The present invention relates to an automatic water supply device for animal drinking and for sprinkling in gardening or horticulture, and more particularly, to an improved automatic water supply device which utilizes siphon action and which supplies water at long-timed intervals in response to lowering of water level in the water tray down to a predetermined level.
In most of the prior art automatic water supply devices or systems for animal drinking, a water supply control means such as a valve, ball tap or the like are usually arranged within or adjacent to a water feeding tray or vessel so that said valve, etc., is actuated when it is touched and moved by the mouth or nose of an animal wishing to drink water.
Therefore, malfunction of this kind of device frequently occurs due to unnecessary engagement of the animal's mouth or nose with such a water supply control means by mere mischief, etc., thereby causing overflow of water on the floor of animal's enclosure without being effectively consumed by the animals, and further making the floor wet and dirty.
Further, with respect to the conventional water supply devices, the water control device such as a valve, etc., is soon damaged by corrosion, and the water tray becomes undesirably large in order to receive the control device therein.
In view of the abovementioned drawbacks, I have proposed an automatic water supply device utilizes a siphon means, in Japanese Patent Application No. 37062/77 filed on Mar. 31, 1977 (Japanese Laying Open Publication No. 122570/78) and in the corresponding U.S. Pat. application Ser. No. 891,172 filed on Mar. 29, 1978, now U.S. Pat. No. 4,202,294, issued May 13, 1980.
The inventor's abovementioned prior invention has solved most of the drawbacks of the conventional devices. However, it has been found that some matters should still be improved with respect to its siphon action.
In the device of the inventor's prior invention, if the size and the arrangement of the inversely J-shaped siphon tube are not proper, water droplets remain in the passage of the siphon tube after the end of the siphoning operation in a manner such that some of the water droplets block an intermediate portion of the passage of the siphon tube, while additional droplets are suspended in the inlet tube portion extending from the top portion of the inversely J-shape siphon tube toward its open inlet end. If this happens, when water is poured into the flow control container for the next siphoning supply of water, the water level in the inlet tube portion of the siphon tube may rise in advance of the water level outside of the siphon tube, and due to this discrepancy between the water levels inside and outside of the siphon tube, the siphoning operation may be inadvertently triggered at an early stage before the container has been filled with a predetermined amount of water.
This sucking up of water is likely to be accompanied by a small amount of dregs of animal food. The water and dregs are raised, gradually by repetition, through the water feed pipe (the long leg of the siphon) until they finally enter into the flow control container, thereby producing dirty water in the flow control container. Although this contamination is sometimes negligible, it is still desirable that it should be definitely avoided.