The present invention relates to a water detection and alert system for detecting the presence of water and leaks from appliances in homes or apartments by employing an extended sensing device that may be conveniently disposed in the form of strips in areas of a home or apartment where water would be expected to accumulate in the event of a leak from an appliance or from cracks or faults in walls which could be expected to seep water. More particularly, the invention pertains to a water detection device employing a resistive sensing system for detecting water in low, shallow pools which as a result of the slowness of the water leak in conjunction to the absorbency of the substrate has the potential of creating serious property damage. The invention employs a sensor system capable of customized disposition and electronic detection and alarm circuit that is compatible with existing fire alarm circuits and a cabinet housing which is mountable at a source removed from the extended sensor.
The prior art includes a variety of patents pertaining to water leak detection devices which are designed to detect water and automatically shut-off an appliance or provide an alarm in the event water is detected in the vicinity of a water using appliance. A significant amount of this prior art utilizes sensing devices of various types and configurations which are not extended or in other words, are confined to a particular area or locality where water will be assumed to collect in the event of a leak. Representative of this prior art are patents such as Hatfield, U.S. Pat. No. 4,020,478, Jui-Cheng Hsu, U.S. Pat. No. 3,562,731, Uhlig, U.S. Pat. No. 3,200,388, and Brown, U.S. Pat. No. 3,770,002.
Referring now to FIGS. 3, 4 and 5, the extended sensor and various modes for the installation and the utilization of the sensing system is illustrated. The extended sensor which consists of a thin strip of flexible mylar 30 preferably having an adhesive backing and preferably two silver ink strips 32 and 34 which are utilized to detect water by monitoring the resistance of the extended sensor. The extended sensor as illustrated in FIG. 4 could be manufactured and purchased from a manufacturer such as Chromerics Inc. by their construction of an extended sensor by the fabrication of mylar and silver ink elements as is similarly used in their micro motion keyboards. Such strips have heretofore been used for keyboards in computer systems but have been found to operate as superior water detection sensing devices when combined with the resistive circuitry. Alternatively, the extended circuitry may be constructed utilizing thin film mylar which then may be coated with silver ink available from such manufacturers as E. I. Dupont, Denemours & Company and other ink supply companies.
In such prior art water detection devices, the efficiency of the detection device is severly limited by the fact that if the water does not reach the water sensor, the alarm will not be sounded even though a slow leak may cause substantial damage since the rate at which the water enters a room may be compensated by the absorption of the water into rugs, cracks between the boards in the wooded floor, and as a result, cause substantial damage to the foundation of a house or to the ceiling and floors below in the case of an apartment.
|Search by Category|