AU2003259649B2 - Precipitation Controlled Switching Device - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT PRECIPITATION CONTROLLED SWITCHING DEVICE The following statement is a full description of the invention, including the best method of performing it known to me.

2 PRECIPITATION CONTROLLED SWITCHING DEVICE FIELD OF THE INVENTION This invention relates to a switching device that is arranged to be controlled by precipitation. The invention has been developed as a switching device for use in controlling a plant watering system and for controlling the operation of a rainwater diverter, and the invention is hereinafter described in these contexts. However, it will be understood that the invention may have broader application, for example in relation to precipitation controlled switching of industrial equipment.

BACKGROUND OF THE INVENTION Plant watering systems as employed in both open gardens and enclosed or semi-enclosed (temperature and/or humidity level controlled) environments typically provide for on-off switching control of water delivery by timing devices. These conventionally comprise devices which range in complexity from simple electro-mechanical timers through to sophisticated micro-processors, and the devices function to turn watering systems on at predetermined times (during predetermined days) and off after the passage of predetermined time intervals.

However, one feature that is shared by all such devices is that they function solely as time measuring devices and, thus, they do not (or cannot) compensate for changes in ambient precipitation levels. That is, in open garden situations, the timing devices are inherently incapable of accommodating changing weather conditions and they can not effect automatic system turn-off if rain or other precipitation exceeds a predetermined level. As a 3 consequence, the conventional time-based switching control can lead to a high level of water wastage, and a similar problem is encountered in the context of the collection and storage of rainwater run-off from building roofs.

In rainwater collection/storage systems, an initial flow of run-off water from a roof is normally diverted to a so-called diverter tank in order to avoid contaminating stored water with material that is deposited on the roof prior to the occurrence of rainfall. The water diversion is maintained until the diverter tank is filled and, thereafter, when the water is directed into the primary storage tank, the diverted water is drained from the diverter tank as waste.

A problem with this system is that wasteful diversion occurs when there are periods between rainfalls that are short relative to the time that is required for significant build-up of contaminating deposits.

The present invention is directed to a device that is intended to overcome or, at least, reduce both of the above discussed problems.

SUMMARY OF THE INVENTION Broadly defined, the present invention provides a precipitation controlled switching device which comprises a switching element, a support element that is moveable between first and second positions, magnet elements positioned and orientated to exert a mutually repulsive force for biasing the support element toward the first position, and a precipitation receiver carried by the 4 support element. The precipitation receiver is arranged to: a) cause the support element to act against the repulsive force exerted by the magnet elements and move to the second position (to effect activation of the switching element) upon receiving an amount of precipitation that increases the effective mass of the precipitation receiver by a predetermined amount, and b) release the received precipitation, following discontinued receipt of precipitation, to enable the repulsive force exerted by the magnet elements to move the support element to the first position whereby the switching element is deactivated.

The invention may also be defined in terms of a watering system that incorporates the above defined switching device, the system further including at least one water delivery conduit that is connectable to a water supply and at least one control valve that is electrically connected to, and actuatable in response to activation and deactivation of, the switching element in the switching device.

The invention may be defined still further in terms of a rainwater storage/diversion system that incorporates the above defined switching device, such system further including a water receiving conduit, waste and storage water delivery conduits, and a control valve that is operable to: a) effect diversion of water to the waste delivery conduit from the water receiving conduit prior to activation of the switching element in the switching device, and 5 b) direct water to the water storage delivery conduit following activation of the switching element.

OPERATION OF THE INVENTION In operation of the above defined switching device, precipitation that is received by the precipitation receiver will increase the effective mass of the precipitation receiver and thereby increase the force that opposes the repulsive force exerted by the magnet elements. When the opposing force exceeds the repulsive force, the support element will move from the first to the second position, to cause activation of the switching element. Conversely, when the supply of precipitation is discontinued, the (previously) received precipitation will be released from the precipitation receiver and the effective mass of the precipitation receiver will be reduced, to enable re-establishment of the initial condition.

The precipitation that effects operation of the above defined switching device will normally exist in the form of falling rain or water that is dripped or sprayed onto the precipitation receiver when the switching element is deactivated. However, the term "precipitation" is to be understood in the context of the present invention as including any form of atmospheric condensate or liquid of any type that falls or is dripped or sprayed onto the precipitation receiver from a source of the liquid.

PREFERRED FEATURES OF THE INVENTION The precipitation receiver preferably comprises a pad of sponge-like material, typically a porous plastics material, that has a high water absorptive capacity. The 6 precipitation receiver when in this form will exhibit a significant increase in effective mass when absorbing precipitation and, as a consequence, provide for positive activation of the switching element. On the other hand, the precipitation receiver in this form will release previously received precipitation by evaporation when the supply of precipitation ceases, enabling it to return to its original mass.

The support element preferably comprises a platform that is pivotably mounted to a carrier and which is moveable angularly between the first and second (pivot) positions.

The support element most preferably comprises a generally rectangular, light-weight plastics material element that carries the precipitation receiver. In this case the precipitation receiver will comprise an absorptive material pad having a shape and size that is similar to that of the platform.

The switching element may comprise a solid state element that is located in an electrical circuit. In such case the switching element may be activated to an on or off condition (as the circumstances require) by a change in circuit conditions induced by, or as a result of, movement of the support element. However, the switching element preferably comprises an electro-mechanical micro-switch that is activated directly or indirectly (as may be required) by movement of the support element with change in effective mass of the precipitation receiver.

In the case of the complete watering system of the present invention, such system provides effectively for climate control of water delivery to garden plants. That is, 7 switching-on of the watering system will be determined by water levels, including prevailing rain levels, sensed by the precipitation receiver, and no turn-on will occur if the rain level exceeds a predetermined level.

The switching device may be located adjacent the control valve or be positioned remotely with respect to the control valve. In the latter case a wired connection may be provided between the switching device and the control valve, or a wireless signal transmission may be employed to actuate the control valve. Also, the switching device may be employed in conjunction with or be integrated with a timer, so as to enable dual function control of the watering system.

In the case of the rainwater storage/diversion system of the present invention, such system provides against wasteful washing of a roof following brief breaks in intermittent rainfall.

The invention in its various aspects will be more fully understood from the following drawing-related description of preferred embodiments of the switching device and systems incorporating the device.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: Figure 1 shows a diagrammatic representation of a watering system incorporating a precipitation controlled switching device, and Figure 2 shows a diagrammatic representation of a rainwater storage/diversion system incorporating the same switching device.

8 DETAILED DESCRIPTION OF THE INVENTION As shown in Figure 1, the switching device 10, in its preferred form, comprises a carrier in the form of a housing 11 to which a support element in the form of a light-weight plastics material platform 12 is pivotably mounted by way of a low friction bearing arrangement 13.

A precipitation receiver in the form of a cellular, porous plastics material sponge 14 is mounted (ie, adhered) to the platform.

The sponge 14 functions in use to absorb precipitation in the form of rainwater and/or delivered water that falls on the switching device 10, and the sponge typically has the dimensions 75mm widexl30mm longxl0mm thick. However, it will be understood that the mass of water absorbed may be varied within wide limits by employing sponge-like materials having different absorptive capacities, surface areas and/or thicknesses.

One of a pair of cylindrical magnet elements 15 and 16 is mounted to the housing 11 and the other is mounted to the underside of the platform 12. The magnet elements are orientated so as to repel one another and, so, to bias the platform to a (first) position away from the housing 11 when less than a predetermined amount of precipitation is absorbed by the sponge 14. However, the magnet elements and 16 are selected so that the repulsive force that they exert will be overcome by the downward force exerted by the platform/sponge combination when the effective mass of the sponge 14 is increased by absorption of a predetermined amount of water. When this occurs, the platform 12 will pivot downwardly to a second position to effect activation of a micro switch 17.

9 The micro switch 17 is located within the housing 11 and has a lever arm that is acted upon by a pin 18 that passes through an aperture within the cover of the housing.

However, other activating mechanisms might be employed, involving, for example, a pair of magnets to avoid the need for the aperture within the cover of the housing.

After water has ceased to fall on the sponge 14 and an ambient water vapour level of less than 100% RH is established, the absorbed water within the sponge will evaporate progressively, to an extent that the upward biasing force exerted by the magnet elements 15 and 16 will exceed the downward force exerted by the platform/sponge combination. At this point the platform will pivot upwardly to the first position and the micro switch 17 will be deactivated.

Although not so shown in the accompanying representation, one of the magnet elements 15 and 16 may be mounted for movement relative to the other, to facilitate adjustment of the repulsive force and, hence, the upward biasing force.

The micro switch 17 is connected electrically in circuit with a power supply 19 and a solenoid actuated flow control valve 20. The valve is provided, when actuated, to connect a source 21 of pressurised water to water delivery conduits 22.

The control valve 20 is actuated to an open condition when the micro switch 17 is deactivated and is actuated to a closed condition when the micro switch is activated. That is, when the sponge 14 is exposed to rain it will become 10 soaked with water and the micro switch will be activated to close the water delivery valve 20. Then, following cessation of the rain, water contained by the sponge will be evaporated, the platform 12 will pivot upwardly and the micro switch 17 will be deactivated to open the water delivery valve 20. Watering of plants will then cause soaking of the sponge 14, either directly or indirectly, to the point where the micro switch 17 will again be activated to close the water delivery valve.

An indicator lamp (not shown) may be incorporated in the electric circuit to provide indication when the watering system is off but power is available from the power supply.

In the rainwater storage/diversion system as shown in Figure 2, a rainwater receiving conduit 24 is arranged to receive runoff rainwater from a building roof (not shown) and to direct the water initially to a waste water (diverting) conduit 25 and, thereafter, to a storage water delivery conduit 26. The waste water delivery conduit directs water to a diverter tank 27 (or, alternatively, to a disposal drain) and the storage water delivery conduit 26 directs water to a storage tank 28 for eventual use.

A solenoid actuated ball valve arrangement 29 is provided for controlling (ie, determining) the direction of water flow from the receiving conduit 24.

The (previously described) micro switch 17 within the switching device 10 is connected in circuit with the power supply 19 (eg, a mains voltage supply) by way of a low voltage transformer 30. Actuation of the micro switch 17 11 results in a low voltage signal being applied to a solid state switch 31 and consequential activation of that switch. The solid state switch 31 when activated provides for a high voltage connection between the power supply 19 and the solenoid actuated ball valve 29.

In operation of the rainwater storage/diversion system; as a starting condition the sponge 14 will be dry and the switching device 10 will not be activated. Also, during an initial period of rainfall the sponge 14 will not be wetted sufficiently to activate the micro switch 17 and rainwater that washes deposits from the building roof during the initial period will be directed to the diverter tank 27.

With continuing rainfall, the sponge 14 will be wetted sufficiently to increase its effective mass to an extent required to cause actuation of the micro switch 17 and consequential actuation of the ball valve 29 to close access to the waste water conduit 25. Continuing runoff of rainwater from the roof will then be directed to the storage tank 28 by way of conduit 26. Following cessation of rainfall, water contained by the sponge 14 will evaporate to re-establish the starting condition but, should the cessation be relatively brief, the evaporation will not be complete, the starting condition will not be re-established and resumption of rainfall will not cause unwarranted re-washing of the building roof.

Variations and modifications may be made in the switching device and the systems as above described without departing from the scope of the invention as defined in the appended claims.

Claims (12)

1. A precipitation controlled switching device which comprises a switching element, a support element that is moveable between first and second positions, magnet elements positioned and orientated to exert a mutually repulsive force for biasing the support element toward the first position, and a precipitation receiver carried by the support element; the precipitation receiver being arranged, in use, to function to: a) cause the support element to act against the repulsive force exerted by the magnet elements and move to the second position, to effect activation of the switching element, upon receiving an amount of precipitation that increases the effective mass of the precipitation receiver by a predetermined amount, and b) release the received precipitation, following discontinued receipt of precipitation, to enable the repulsive force exerted by the magnet elements to move the support element to the first position whereby the switching element is deactivated.

2. The switching device as claimed in claim 1 wherein the precipitation receiver comprises a pad of sponge-like material that has a water absorptive capacity.

3. The switching device as claimed in claim 2 wherein the precipitation receiver comprises a porous plastics material of a type that exhibits a significant increase in effective mass when absorbing precipitation and which releases previously received precipitation by evaporation when the supply of precipitation ceases. 13

4. The switching device as claimed in any one of the preceding claims wherein the support element comprises a platform that is pivotably mounted to a carrier and which is moveable angularly between the first and second (pivot) positions.

The switching device as claimed in claim 4 wherein the support element comprises a generally rectangular, light- weight plastics material element that carries the precipitation receiver.

6. The switching device as claimed in any one of the preceding claims wherein the switching element comprises an electro-mechanical micro-switch that is activated by movement of the support element with change in effective mass of the precipitation receiver.

7. The switching device as claimed in any one of the preceding claims wherein the magnet elements are adjustably moveable relative to one another whereby the repulsive force may be varied.

8. The switching device substantially as shown in the accompanying drawings and substantially as hereinbefore described with reference thereto.

9. The switching device as claimed in any one of the preceding claims incorporated in a watering system which includes at least one water delivery conduit that is connectable to a water supply and at least one control valve that is electrically connected to, and actuatable in 14 response to activation and deactivation of, the switching element in the switching device.

The watering system substantially as shown in Figure 1 of the accompanying drawings and substantially as hereinbefore described with reference thereto.

11. The switching device as claimed in any one of claims 1 to 8 incorporated in a rainwater storage/diversion system that includes a water receiving conduit, waste and storage water delivery conduits, and a control valve that is operable to: a) effect diversion of water to the waste delivery conduit from the water receiving conduit prior to activation of the switching element in the switching device, and b) direct water to the water storage delivery conduit following activation of the switching element

12. The rainwater storage/diversion system substantially as shown in Figure 2 of the accompanying drawings and substantially as hereinbefore described with reference thereto. Barrie R.D. Gillings Sydney, 03 November 2003