Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2000-03-20
2001-05-15
Lieu, Julie (Department: 2736)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S605000, C340S618000, C340S620000, C340S539230, C340S870030, C340S870030
Reexamination Certificate
active
06232883
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of water alert systems. More particularly, the present invention relates to a water activated power supply for signaling a control device of the detected presence of a body of water, and for triggering a bistate device upon the detection of a body of water.
2. Background
Water alert devices including a power source and a water activated switching circuit for triggering a bistate device, e.g. a horn, or a transmitter, are well known in the prior art. For example, see, U.S. Pat. Nos. 3,810,146; 4,079,364; 4,714,914; 4,777,478; 5,025,247; and 5,710,989. Typically, the power source is a battery, and the water activated switching circuit includes a transistor switch, a voltage divider, and a water activated switch in the form of a pair of electrodes. The horn or transmitter is electrically coupled between a positive terminal of a battery and a collector terminal of the transistor switch; the electrodes and the voltage divider are coupled in series between the positive terminal of the battery and a negative terminal of the battery; a base terminal of the transistor switch is electrically coupled to the voltage divider; and an emitter terminal of the transistor switch is electrically coupled to the negative terminal of the battery. The battery and the base terminal of the transistor switch are electrically uncoupled in the absence of both electrodes being simultaneously immersed in a body of water. Consequently, the transistor switch is in a cutoff mode of operation due to the lack of current to the base terminal of the transistor switch, and the transistor switch does not draw current from the battery. As a result, the horn or transmitter serially connected with the transistor switch is in a deactivated state of operation. The battery and the base terminal of the transistor switch are electrically coupled when the electrodes are simultaneously immersed in a body of water. Consequently, the transistor switch transitions to a saturation mode of operation due to the supply of current to the base terminal of the transistor switch, and current is drawn from the battery by the transistor switch to activate the horn or transmitter.
One problem associated with the utilization of a water activated switching circuit is that the magnitude of current supplied to the base terminal necessary to transition and maintain the transistor switch in a saturation mode of operation during the simultaneous immersion of both electrodes in a body of water can be relatively significant. Consequently, the usable life of the battery can be significantly reduced. Another problem with the utilization of a water activated switching circuit is the magnitude of the current drawn by the load placed on the battery due to the horn or transmitter during the simultaneous immersion of both electrodes in a body of water. This load can also significantly reduce the usable life of the battery. What is therefore needed is a water activated means for drawing a negligible amount of electrical power from a power source. What is also needed is a water activated means for isolating the power source from an external load device electrically coupled to the water activated means, e.g. a horn or a transmitter.
SUMMARY OF THE INVENTION
The present invention overcomes the aforementioned drawbacks associated with prior water activated switches. Various aspects of the present invention are novel, non-obvious, and provide various advantages. While the actual nature of the present invention described in detail herein can only be determined with reference to the claims appended hereto, certain features which are characteristic of the present invention disclosed herein can be described briefly.
In accordance with a first aspect of the present invention, a water activated power supply comprises a power source, transistor, and water activated switch. The power source is operable to provide a first electrical power. The transistor consists of a base terminal, a collector terminal electrically coupled to the power source, and an emitter terminal. The water activated switch is operable to conduct the first portion of the first electrical power to the base terminal of the transistor when a body of water contacts said water activated switch whereby the emitter terminal provides a second electrical power.
In accordance with a second aspect of the invention, a water alert device comprises a water activated power supply and a transmitting unit including an encoder and a transmitters. The encoder is operable to provide a transmission word in response to electrical power from the water activated power supply. The transmitter is operable to provide a transmission signal in response to the transmission word and electrical power from the water activated power supply.
In a third aspect of the present invention, a water alert system comprises a water activated power supply, a transmitting unit, and a receiving unit including a receiver and a decoder. The transmitting unit is operable to provide a transmission signal in response to electrical power from the water activated power supply. The receiver is operable to provide a transmission word in response to the transmission signal. The decoder is operable to provide a detection signal that transitions between a first logic state and a second logic state as a function of the absence and presence of the transmission word.
It is a primary objective of the present invention to provide a water activated power supply including a power source and a buffering circuit that isolates the power source from an external load device electrically coupled to the buffering circuit when a body of water and/or another ionized liquid has been detected by the buffering circuit.
It is a secondary objective of the present invention to provide a water activated power supply including a power source, and a buffering circuit that can draw a negligible amount of electrical power from the power source when a body of water and/or another ionized liquid has been detected by the buffering circuit.
These and other objects and advantages of the present invention will become more apparent from a review of the following description of the preferred embodiments of the present inventions.
REFERENCES:
patent: 3810146 (1974-05-01), Lieb
patent: 4079364 (1978-03-01), Antenore
patent: 4264901 (1981-04-01), Petersen et al.
patent: 4714914 (1987-12-01), Boe
patent: 4777478 (1988-10-01), Hirsch et al.
patent: 5025247 (1991-06-01), Banks
patent: 5311100 (1994-05-01), Brain
patent: 5710989 (1998-01-01), Flood
McQueary Steven Dale
Silva Kevin DeVere
Lieu Julie
Uncle Albert's LLC
Woodard Emhardt Naughton Moriarty & McNett
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