Detection device for electrically conductive fluids

A device for detecting the presence of electrically conductive fluids, and upon such detection functioning to provide an audio alarm signal, and/or terminate electrical power to equipment that is causing fluid leakage. When used in conjunction with a washing machine, wherein the tube over-flows, or the pump or pump discharge hose leaks to cause water spillage, or where leakage occurs from the machine's cold or hot water supply hoses, the device will operate to deactivate the water pump and water supply solenoid valves, and provide an audio signal. Also, the device may be used to provide an audio alarm signal, and/or provide electrical power to a stand-by emergency pump to withdraw fluids, and prevent flooding. The device features a fluid sensing unit and a control unit operating on 90 to 125 volts AC low current. The fluid sensing unit has adjacently disposed large surface area neutral and hot contacts to allow sufficient current to flow between contacts and through the electrically conductive fluid, to improve circuit breaker response. When fluid accumulates between the neutral and hot contacts, a circuit is completed to instantaneously trip the circuit breaker to control electrical power to the outlet socket, and activate the audio alarm.

BACKGROUND OF THE INVENTION 
This invention relates to a device for detecting the presence of 
electrically conductive fluids, and upon such detection functioning to 
provide an audio alarm signal, and/or terminate electrical power to 
equipment that is causing fluid leakage. More particularly, this invention 
can be used to detect any malfunction in the operation of a washing 
machine. Should the machine tub becomes inadvertently over-filled due to 
failure of the level sensing system or should the pump or pump discharge 
hose leak to cause water spillage, or should leakage occur from the 
machine's cold or hot water supply hoses, the device will operate to 
deactivate the machine's water pump and supply solenoid valves, and 
provide an audio signal. Also, a further use of this invention would be to 
sense basement flooding, and utilize the control unit to activate a 
stand-by emergency pump and audio alarm. The fluid detection device of 
this invention consists of a control unit operatively associated with a 
fluid sensing unit for monitoring fluid leakage. 
Numerous moisture detection devices are available, such as disclosed in 
U.S. Pat. No. 4,380,243. These devices operate on low direct current 
voltage, and are of electronic construction. Since households are provided 
with approximately 110 volts AC power, said voltage must first be stepped 
down and then converted to DC. Components to provide said functions add 
substantially to the cost of such moisture detection devices. The instant 
invention operates on low current 90 to 125 VAC, thus eliminating the need 
for the costly components associated with prior art moisture detection 
devices. 
SUMMARY OF THE INVENTION 
The instant invention features a fluid sensing unit operatively connected 
to a control unit, for monitoring fluid leakage and for providing 
maintained termination of electrical power to a washing machine's water 
pump and water supply solenoid valves. Also, should the cold and/or hot 
water supply hoses and/or pump discharge hose leak, the detection device 
will operate to provide an audio alarm signal. 
The fluid sensing unit is positioned on the floor behind or underneath the 
washing machine. Should water spill upon the floor, it will enter the 
fluid sensing unit to surround the neutral and hot contacts. In so doing, 
an electrical circuit will be completed to provide a signal to the control 
unit to trip the circuit breaker when the current flow exceeds the low 
value of approximately 0.020 to 0.060 amperes. It should be noted that 
adjacent surface areas between the hot and neutral contacts that are 
wetted by electrically conductive fluid such as water, must be of such 
magnitude as to allow sufficient current to flow therebetween, for circuit 
breaker tripping. The greater the magnitude of surface area between the 
hot and neutral contacts wetted by water, and the smaller the gap between 
said contacts, the faster will be the response of the circuit breaker. 
The main advantage of this invention over prior art devices, relate to its 
simplicity in construction. Thereby, being more economical to build, and 
easier to maintain.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
With reference to FIGS. 1, 2, 3, 4, and 5, it can be discerned that the 
invention comprises a fluid sensing unit 1 for sensing the presence of a 
conductive fluid, and a control unit 24 for providing maintained 
termination of electrical power to a washing machine for de-energizing its 
water pump and water supply solenoid valves, and for activating audio 
alarm 29. 
In the preferred embodiment depicted in the drawing, fluid sensing unit 1 
comprises circular body 2, neutral annular contact 3, hot annular contact 
4, connecting wires 5 and 6, right angle male tabs 7 and 8, potting 
compound 9, and thin insulation shield 10. Body 2 is made from a 
dielectric material, such as plastic, having bore 11 at the top end, and 
outer bore 12, intermediate bore 13, and inner bore 14 at the bottom end, 
which are concentric to each other and stepped progressively inward. In 
addition, body 2 has holes 15 and 16 to accommodate the passage of 
connecting wires 5 and 6, and a plurality of radially disposed cut-outs 17 
at the bottom which are defined by upper surface 18 and side surfaces 19. 
Also, neutral annular contact 3 has at its bottom end a plurality of 
radially disposed cut-outs 21 defined by upper surface 22 and side 
surfaces 23. Fluid sensing unit 1 is fabricated by securing the hot 
annular contact 4 within inner bore 14, and the neutral annular contact 3 
within intermediate bore 13. Right angle male tab 7 is located within bore 
11 upon surface 20, and interconnected to neutral annular contact 3 by 
means of copper wire 5, whose ends are soldered to the tail of male tab 7 
and to the outer top surface of neutral annular contact 3. Right angle 
male tab 8 is also located within bore 11 upon surface 20, and 
interconnected to hot annular contact 4 by means of copper wire 6, whose 
ends are soldered to the tail of male tab 8 and to the inner top surface 
of hot annular contact 4. Bore 11 is then filled with potting compound 9 
to permanently encapsulate male tabs 7 and 8 within body 2. Insulation 
shield 10 can be made from a thin sheet of rubber or plastic adhered to 
the bottom surfaces of body 2, neutral contact 3, and hot contact 4. As an 
alternative, insulation shield 10 may be eliminated completely, or the 
bottom ends of the neutral and hot annular contacts 3 and 4 coated with 
wire insulating enamel. 
Control unit 24 includes enclosure 25 of such construction as to mount 
directly to an electrical wall receptacle. Secured to the back face of 
enclosure 25, is plug 26 having protruding prongs for engagement with the 
electrical wall receptacle. Mounted to the bottom face of enclosure 25 is 
commercially available socket 27, for receiving the washing machine power 
supply cord plug. Also, the bottom face of enclosure 25 has a two 
conductor electrical lead 34 protruding therefrom, for connection to male 
tabs 7 and 8 by means of quick disconnect terminals 35 and 36. Fixedly 
mounted to the front face of enclosure 25 is commercially available 
circuit breaker 28, and mounted to the side face is commercially available 
audio alarm 29. It should be noted that audio alarm 29 may be located 
remotely, and also have a switch connected in series with it for 
deactivation, if so desired. 
In operation, with electrical power to plug 26 and with circuit breaker 28 
in the "On" position, electrical power will be available to socket 27 
through the normally open (N.O.) contacts of auxiliary switch contacts 30, 
for washing machine use. Should the washing machine tub overflow, and/or 
water pump, and/or pump discharge hose, and/or water supply hoses leak, 
fluid sensing unit 1 will receive water through the plurality of radial 
cut-outs 17 and 21. Said radial cut-outs 17 and 21 represent means for 
admitting fluid into the fluid sensing unit. The entering water will 
accumulate between neutral contact 3 and hot contact 4 to complete a 
circuit through said water and allow current to flow through coil contacts 
32 and coil 31. It should be noted that said current must be of such 
magnitude as to energize circuit breaker coil 31 for instantaneous 
tripping of circuit breaker reset lever 33 to the "Off" position. In the 
"Off" position, coil contacts 32 will open to de-energize coil 31. Also, 
the normally open (N.O.) contacts of auxiliary switch 30 will become open 
to terminate power to socket 27, and the normally closed (N.C.) contacts 
will close to activate audio alarm 29. Circuit breaker 28 can be manually 
reset to the "On" position by moving reset lever 33 up-ward to the 
un-tripped position, to reset coil contact 32 to the closed position. 
Also, the normally closed (N.C.) contacts of auxiliary switch 30 will 
become open, and the normally open (N.O.) contacts will become closed, 
such as shown in FIG. 5.