WO2006138303A2

WO2006138303A2 - Exhaust fan controller

Info

Publication number: WO2006138303A2
Application number: PCT/US2006/022974
Authority: WO
Inventors: Clifford Roux; Dale Mark Anderson; Glenn C. Skelton
Original assignee: Black Box Innovations, Inc.
Priority date: 2005-06-14
Filing date: 2006-06-13
Publication date: 2006-12-28
Also published as: US20080011863A1; CA2612390A1; WO2006138303A3; EP1907763A2; JP2008546975A; US20060286922A1

Abstract

An exhaust fan controller to turn on an exhaust fan and dry out a confined space in the event that a factory predetermined moisture level has been exceeded, thereby limiting any destruction or health risks caused by negligence on the part of users or infrequent maintenance. The controller is manufactured in such a way that all electronic components, sensor, and pc board mounting fit into any ordinary switch box in a building electrical system and wire directly into the already installed wiring for the manual switch that it will replace.

Description

EXHAUST FAN CONTROLLER

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention pertains to a controller and, more particularly, to a controller for a fan, such as an exhaust fan, that detects the presence of water and activates the fan, preferably for a set period of time.

Description of the Related Art

The invention provides a solution to fungal and bacterial destruction of materials used in construction of, or being stored in moist environments. The current state of the art is both inadequate and not functional to provide protection that can be relied upon to properly maintain dry conditions where considerable economic loss may be entailed by both user and maintenance personnel not switching on the exhaust fan manually at all, or for such short times as to be ineffective as a means of preventing the accumulation of both fungal and bacterial outbreaks that are health threatening and destructive of the structures or stored objects themselves. This situation has long been and still is a large and growing economic and health problem which this invention addresses in a cost effective and practical way.

BRIEF SUMMARY OF THE INVENTION The disclosed embodiments of the invention are directed to a controller for a fan that is adapted to be used in environments in which moisture in the form of condensation is undesirable. In accordance with one aspect of the invention, a controller for a fan is provided, the controller includes a sensor adapted to detect the presence of condensed water, and a circuit coupled to the sensor and adapted to control operation of the fan in response to the sensing of condensed water by the sensor. In accordance with another aspect of the invention, a controller for an exhaust fan is provided that includes a sensor having electronic leads adapted to be bridged by condensed moisture to conduct current, and a circuit coupled to the sensor and adapted to control operation of the fan in response to the flow of current in the sensor.

In accordance with another aspect of the present invention, the controller is fully automated in that it automatically activates the fan when condensed water is detected on the sensor and maintains activation of the fan for a set period of time. Alternatively, the controller can be adapted to permit manual deactivation of the fan or to permit both manual deactivation and automatic deactivation of the fan.

In accordance with another aspect of the present invention, the sensor and the circuit are hardwired together and the circuit is coupled to the fan via either a hardwire or a wireless connection. In accordance with another aspect of the invention, the sensor is formed from exposed electrically-conductive leads that are designed to conduct current when the leads are bridged by condensed moisture.

In accordance with another aspect of the present invention, the circuit is adapted to compare the amount of current conducted by the sensor with a reference current and to activate the fan when the conducted current by the sensor is at an appropriate level.

In accordance with another aspect of the present invention, the controller utilizes an optical coupler to isolate high voltage or high current circuit components from low voltage components, such as sensing and switching components.

The invention is an electronic circuit sensing moisture in any enclosed space (especially a bathroom with shower/tub) and by the use of appropriate signal conditioning, amplification, timing and on-site power switching causing the already installed exhaust fan to be switched on for a time appropriate to dry the affected space and then be automatically switched off. (In the case of the average residential bathroom this is about 20 min.) The practical application of the invention requires the use of miniature electronic components to fit into the space provided for and replacing an ordinary and standard manual switch used to switch on a room or other chosen space, exhaust fan. This invention requires no additional wiring to the building's electrical system and is a direct replacement for the manual exhaust fan switch installed as standard practice in all toilet and/or shower facilities.

The invention makes the decision to turn on the exhaust fan and dry out the confined space in the event that a factory predetermined moisture level has been exceeded, thereby limiting any destruction or health risks caused by negligence on the part of users or infrequent maintenance. Periodic maintenance schedules are often extended so far as to be ineffective in moisture control. In one embodiment, the controller of the present invention takes the option to turn off the exhaust fan out of a user's control but not the option to turn it on. The invention is manufactured in such a way that all electronic components, sensor and pc board mounting fit into any ordinary switch box in a building electrical system and wire directly into the already installed wiring for the manual switch which it will replace.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS The foregoing features and advantages of the present invention will be more readily appreciated as the same become better understood from the following detail description when taken in conjunction with the accompanying drawings, wherein:

Figures 1 A - 1 C are a schematic of an exhaust fan controller formed in accordance with the present invention;

Figures 2A and 2B are illustrations of alternative applications for the exhaust fan controller formed in accordance with the present invention; and

Figures 3A and 3B are an illustration of an alternative embodiment of an exhaust fan and accompanying controller formed in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION

Referring to the Vent Fan Controller Schematic shown in Figure 1 , the components with reference labels SENS 1 , R7, R1 , R2 & R3, Q1 , and U2 comprise the moisture sensing and post sensing conditioning circuit. The moisture sensor itself has in this case been chosen for its cost effect manufacture and low component requirements to reliably trigger the rest of the exhaust fan controller circuitry. In one embodiment, it has been made as a half inch by half inch PC board with gold leads arranged as two interleaved four pronged forks spaced at about 1/20 an inch between the tines. (Refer to Figure 1 , SENS1 symbol details on the schematic). This is not the only sensor configuration that we have found suitable to reliably detect moisture vapor, as we have shown by experiment the more expensive sensor found in generic smoke detectors can be readily used with the appropriate changes to the sensing circuit component values, which will result in the invention working in an identical fashion but not as inexpensive to produce.

The NPN transistor(QI) receives the "moisture present" signal from the sensor and shapes it appropriately to be used to drive the LM311 Comparator (U2), which, when the appropriate level is reached as determined by comparison to a reference current, will trigger the LS7213 Timer (U5) to drive the output triac (U4) for the appropriate time chosen, which is established by the values of R9 and C5. Nominal time is 20 min. Other values chosen for particular applications are adjustable from 1 second to hours. A signal from the Timer IC (L)5) pin 12 thru resister R11 to D2 will light the LED whenever the exhaust fan is on. The LED is optional but recommended. IC U1 is a triac driver optical coupler used to isolate the 110V AC being switched on and off by the triac to the exhaust fan motor. This optoisolation decouples the triac 110V AC switching current from the low voltage supplied IC and transistors of the circuits.

The low voltage power supply shown is standard engineering practice. In Figure 1 the miniature transformer (T1), full wave bridge rectifier (D1), electrolytic capacitor (C1), and the IC 5 volt regulator (U3) supply the necessary regulated 5vdc to the entire circuit. Capacitors C2, C3, C4, and C6 are bypass capacitors necessary to short unwanted voltage transients to ground.

We have also found by experiment that the power supply can benefit from slight changes, substituting a 9V DC regulator to supply the entire circuit, with the exception of the LSI timer, which requires a 5V DC regulator. This makes a much more sensitive circuit, both in the lower level of moisture vapor it will detect and the speed of its response.

Figure 1 also shows the single 5V DC regulator option for the entire controller. While this makes it less sensitive to the amount of moisture vapor present, taking several minutes to switch on the exhaust fan motor, in most applications this delay is insignificant. In others the dual supply (9V DC and 5V DC) regulators are preferred as being more sensitive and timely.

The light switch circuit shown at the bottom right of Figure 1 is another option for sites that may operate both the exhaust fan and the lights from the same manual switch. The miniature low voltage switches shown on the Schematic (SW1 and SW2) make the manual switching functions of turning on the fan motor at will, or turning the room lights on and off possible from a electrical box that formerly held only one manual electrical switch. Again, the optocoupler (U6) isolates the AC being switched at the triac (U7) from the low voltage portions of the circuits. The detailed parts list is shown below:

Vent Fan Controller Rev 04

Sensor Board Rev 01

The invention provides an economical and practical means to detect and exhaust moisture vapor from indoor spaces. In checking patents published on the USPTO website, none were found to address or to be aimed at detecting and exhausting moisture automatically from indoor spaces, as this invention provides. There is on the market a manually adjustable humidity sensor, requiring and/or allowing the user to determine if or when the exhaust fan motor will be switched on. The present invention is wholly dissimilar in several ways. First, the present invention is not based on sensing humidity, but the more direct moisture or condensation sensing. Second, the invention in one embodiment is truly automatic and does not allow users the option of turning the fan motor off, but only to turn it on. The third major difference is the adaptability of the various means the circuits offer to different room and electrical installations to accomplish condensation sensing and fan control.

In the detail show in Figure 2A the vent fan controller is configured to be installed as a direct replacement of an ordinary fan motor control switch. The configuration in Figure 2B takes advantage of the flexibility allowed in new installations, as this allows the exhaust fan and the controller to be mounted on the ceiling of the subject room and permanently wired there before the room walls are installed.

Figure 3A depicts a configuration that would mount on the ceiling of larger rooms, possibly in multiples, and using only the sensor, signal conditioning circuit, and a miniature radio frequency transmitter, would become the monitor of moisture events from the more ideal location on the ceiling. Upon triggering, this unit would send a radio frequency "moisture present" signal to a wall mounted receiver, timer, and triac controller, which would turn on the vent fan motor or motors in the case of multiple installations. The wall- mounted unit can also include its own sensor.

Each of these different adaptations of the basic invention are necessary in certain indoor situations, but it should be noted that all of them could utilize either the small gold tined fork sensor of Figure 1 or the sensor found in any generic smoke detector interchangeably if each sensor is given its suitable signal conditioning circuit.

Claims

1. A controller for a fan, comprising: a sensor adapted to detect the presence of condensed water; and a circuit coupled to the sensor and adapted to control operation of the fan in response to the sensing of condensed water by the sensor.

2. The controller of claim 1 wherein the circuit is adapted to activate the fan for a fixed period of time.

3. The controller of claim 1 wherein the sensor comprises exposed leads that conduct current when the leads are coupled together by condensed water.

4. The controller of claim 3 wherein the circuit is configured to compare current conducted by the sensor in the presence of condensed water to a reference current and to activate the fan when the current from the sensor reaches a level of the reference current.

5. A fan for exhausting air, the fan comprising: a motor for rotating the fan; and a controller for the motor, the controller comprising: a sensor adapted to detect the presence of condensed water; and a circuit coupled to the sensor and adapted to control operation of the motor in response to the sensing of condensed water by the sensor.

6. The fan of claim 5 wherein the circuit is adapted to activate the fan for a fixed period of time.

7. The controller of claim 5 wherein the sensor comprises exposed leads that conduct current when coupled together by condensed water.

8. The controller of claim 7 wherein the circuit is configured to compare current conducted by the sensor to a reference current and to activate the fan when the current from the sensor reaches a level of the reference current.

9. A fan controller, comprising: a sensor configured to detect moisture condensed from water vapor; and a circuit coupled to the sensor and configured to operate the fan when the sensor detects the moisture.

10. The fan controller of claim 9 wherein the circuit coupled to the sensor is configured to operate the fan for a fixed duration of time when the sensor detects the moisture condensed from water vapor.

11. The fan controller of claim 9 wherein the circuit coupled to the sensor is configured to alert a user when the sensor detects moisture condensed from water vapor.

12. A method for reducing humidity in an enclosed area, the method comprising: detecting water condensed from water vapor; and activating a fan for a fixed duration of time in response to detecting water condensed from water vapor.

13. The method for reducing humidity of claim 12 further comprising checking repeatedly for the presence of water condensed from water vapor after the fixed duration of time and activating the fan for the fixed duration of time in response to detecting water condensed from water vapor.

14. The method of reducing humidity of claim 12 further comprising illuminating a light source in response to detecting water condensed from water vapor.

15. A method for reducing humidity in an enclosed area, the method comprising: detecting condensation using a sensor; processing an output signal from the sensor; and activating a fan for a fixed duration of time in response to the output signal from the sensor.

16. The method of reducing humidity of claim 15 further comprising operating the fan manually.

17. A device for eliminating water vapor from an enclosed area, the device comprising: a condensed water detector; a first circuit having an automatic switch to activate a fan assembly when condensation is detected by the detector; and a second circuit coupled to the first circuit, the second circuit having a manual switch for controlling the fan assembly.

18. The device of claim 17 wherein the first circuit coupled to the sensor is configured to illuminate a light when condensation is detected by the detector.

19. A fan assembly, the assembly comprising: means for sensing condensed water vapor; and means for activating a fan when the sensing means detects the condensed water vapor.

20. The fan assembly of claim 19 wherein the means for activating the fan is configured to alert a user to the sensing of condensed water vapor.