Field of the Invention The present invention relates to a sprinkler control system for the prevention of an undesired condition, and, in particular, a system for controlling for spread of bush fires to properties.

Background Art Uncontrolled bush fires can present a serious hazard to both people and property.

Most systems available to control bush fires are manually operated and use either petrol or diesel driven pumps that drive pumps or hoses that run off the water supply. This can present a number of problems-in particular, that they depend upon the presence of a power supply (which may not be present), and require the presence of someone to operate the system. However, it may not always be possible for people to remain in the vicinity of the bushfire because of the severity of the bushfire, or due to Fire Brigade rulings. The pumps may not always operate, and they use up large volumes of water-which may not always be available.

Disclosure of the Invention According to the present invention, there is provided a sprinkler control system comprising: a network of sprinklers connected by a system of piping; pump means for pumping a liquid through the network of sprinklers ; sensing means for detecting the existence of a predetermined condition; and control means coupled to the pump means and the sensing means, and operable, in response to the existence of the predetermined condition, to activate the pump means for predetermined period of time to pump liquid through the network of sprinklers, the control means being further operable, if the control means determines that, after

the predetermined period of time elapses, the predetermined condition is still present, to continue activation of the pump means.

The cycle of re-activation of the pump means may be continued until the predetermined condition is no longer detected.

The control means may comprise a microprocessor and associated circuitry and is held in an first condition until the predetermined condition is determined, the sensing means being operable, in response to the presence of the predetermined condition, to provide an sensor condition such that, in response, the control means switches to a second condition whereby the pump means is activated for the predetermined period of time, under control of timer means provided in the control means.

The predetermined condition may be a temperature above or below a predetermined threshold value.

The sensing means may comprise at least one sensor, and includes mounting means for mounting the at least one sensor a predetermined distance from a surface around which the system is used. The predetermined distance may be at least one metre.

Each sensor may comprise a magnesium strip in a metal casing, whereby, at the threshold value, the magnesium strip abuts the casing thereby providing the open circuit condition.

The predetermined period of time may be manually selected.

The control means may be further operable to activate the pump means for a second predetermined period of time at regular intervals.

The system may further include power means for the control means. This may include a battery and a solar panel for charging the battery.

The control means may be further operable, in response to signals from pump means, sensor means, or power means, to indicate failure of the pump means, sensor means, or power means to activate the pump means to pump the liquid through the network of sprinklers.

The control means may further include alarm means operable to activate in response to detected failure of the pump means, sensor means, or power means.

The sprinkler control system may further include liquid holding means coupled to the pump means, the liquid holding means being arranged to collect the liquid after discharge from the sprinkler network.

According to a second aspect of the present invention, there is provided a method for preventing an undesired condition, the method including the steps of: providing a network of sprinklers connected by a system of piping; detecting the existence of a predetermined condition; pumping a liquid through the network of sprinklers, in response to the existence of the predetermined condition, for predetermined period of time; and determining, after the elapsing of the predetermined period of time, if the predetermined condition still exists and, if the predetermined condition is still present, to continue pumping the liquid through the sprinkler network.

The advantage of the present invention is that the system is fully automated and will operate when certain conditions are detected. The system will also activate where there is a failure of component parts of the system.

Brief Description of the Drawings The invention will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figure 1A is a schematic plan view of a house upon which the system of the present invention is provided; Figure 1 B is a schematic perspective view of the house in Figure 1A showing the arrangement of sprinklers and sensors; Figure 2 is a schematic block diagram illustrating the constituents of the present invention without the sprinkler system; Figure 3 is a schematic block diagram illustrating the solar panel, battery, sensors, pump motors are linked to the control unit; Figures 4a and 4b are a circuit diagram for the control unit and some of the associated components of the sprinkler control system of the present invention, with Figure 4b being a continuation of Figure 4a; Figure 5 is a circuit diagram for a regulator used in the control unit of the present invention; and Figures 6A and 6B are schematic illustrations of the sensor used in the system of the present invention.

Best Mode (s) for Carrying Out the Invention Throughout the specification, unless the context requires otherwise, the word "comprise"or variations such as"comprises"or"comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Referring now to Figures 1A and 1B. A house or other building 100 includes a roof 101 upon which is mounted a network 1 of sprinklers 2a, 2b. The sprinkler network is part of a sprinkler control system 200, which will be further described below. The term"sprinkler"is used to means a device capable of spraying water (or other liquids) in a predetermined direction and over a predetermined area.

In the present embodiment, sprinklers 2a mounted around the bottom perimeter 102 of the roof 101 are arranged to spray water over 180 degrees, with an overlap of 30 degrees, over the sidewall of the house and any adjacent structure, such as a veranda (not shown). Sprinklers 2b mounted upon the roof 101, for example upon the apex 103, and gable edges 104 are designed to spray water over a full 360 degrees, and the sprays from these sprinklers 2b also overlap. This ensures that the outside structure of the house 100 can be completed covered by water sprayed from these sprinklers 2a, 2b. The sprinklers 2a, 2b can be of any suitable type designed to spray water over a predetermined areas, and it will be readily understood that other arrangements of sprinklers can be used. The sprinklers 2a, 2b are connected in series by means of piping 3, through which water is pumped.

In the present embodiment, the piping is made from a high-density, fire-retardant material suitable for carrying appropriate volumes of water.

Water for this network 1 is provided from a storage tank 4, from which water is pumped using a pump 5. The pump is operated using pump motors 13 under control of a control unit 6, as will be described in further detail below. The control unit 6 is provided with power from a battery 8. A solar panel 7-which in this embodiment is mounted upon the roof 101, but may be located elsewhere-is used to recharge the battery 8 by providing a trickle charge to the battery as is well known to persons skilled in the art. The solar panel 7 can be of any suitable, known type. A regulator 28 is provided to ensure that current flow between the solar panel 7 and the battery 8 is in a single direction-see Figure 4. The circuit diagram of Figure 5 is for the regulator 19.

The pump 5 is connected to the tank 4 by means of piping 11, similar to that used in the sprinkler network 1. In the present embodiment, the pump 5 can be any pump capable of pumping water at between 40 and 70 pounds per square inch. although other suitable pumps for other pressures can be used.

Also provided above the roof 101 are a number of sensors 9 for sensing the temperature of the air above the roof 101. In the present embodiment, the sensors 9 are mounted along the apex 103 of the roof 101 on poles at least one metre above the height of the roof 101. The sensors are located at this distance

to ensure that any effects from radiant heat from the roof is minimised. In order to achieve this, the sensors are provided with mounts 25. These mounts are made from any suitable metal with heat insulation. A number of sensors 9 are provided - in this embodiment, three are used, but other numbers can be used. The sensors 9 are coupled in series to the control unit 6-as will be described in further detail below. The sensors 9 are coupled to the control unit 6, or to an adjacent sensor) by means of suitable terminal lines 23 and-when coupled to the control unit 6-a connector 24. The connector 24 allows the sensors 9 to be detachably connected to the control unit 6 to facilitate removal-if required. Any suitable connector can be used. In Figure 2, only a single sensor 9 is illustrated- for clarity.

The water for the tank 4 is rainwater supplied by means of suitable drainage facilities 10 connected between the roof 101 and the tank 4. This drainage 10 also allows water sprayed through the sprinkler network 1 during use to be collected and reused.

As mentioned above, the pump motor 13 (and thereby the pump 5) is under control of the control unit 6. This is illustrated schematically in Figure 2. In the embodiment described herein, there are four pump motors 13 each with an associated pump 5, each connected to a sprinkler network, each of the sprinkler networks being interconnected. Figures 2,3 and 4 indicate the four pump motors 13, although in the Figures 1 and 2 only a single pump 5 is shown-again for clarity. However, it should be understood that all of them operate in a similar manner. The pump motor 13 operates to drive the pump 5-as is well known to persons skilled in the art. All the sprinkler networks operate in an identical fashion, although the actual arrangement of the network around a property may vary depending upon the building or environment that is to be protected. Each pump motor 13 is provided with relay 19 and fuse 17. The fuse 17 is a resettable trip switch.

The control unit 6 comprises a microprocessor 12, which is also coupled to the sensors 9 and operates the pump motor 13 in response to the state of the sensors 9-as will be described below.

Figure 3 schematically illustrates the main component parts of the sprinkler control system and how they are linked.

Figure 4 is a circuit diagram showing in further detail these component parts and associated circuitry. It will be appreciated by persons skilled in the art that the other suitable circuit arrangements may be available. In addition to the components discussed above, the circuitry includes three thermistors 26a, 26b, 26c, which are used to minimize pulsing and to detect faults in the components or associated circuitry as will be discussed in further detail below. An oscillator 27 provides the clock input for the microprocessor 12. An oscillator 31 is for the alarm 15.

The microprocessor 12 is also coupled to a manually operated selector switch 14, which can be used to switch for manual selection of various operating programs (if required). The selector switch could be provided in the form of a rotary pivot switch, keypad (or a combination of the two) or other suitable type. An ON/OFF switch could also be provided-if required. An audible alarm 15 is provided which is triggered in response to a signal from the microprocessor 12-see Figure 4b.

In use, the sensors 9 detect the change in the air temperature that results from a nearby bushfire. Each sensor 9 comprises a magnesium strip 16 mounted within a metal casing 20. This is illustrated schematically in Figures 6A and 6B. The casing 20 and magnesium strip 16 are coupled to terminal lines 23 into the microprocessor 12, or coupled to another sensor 9-see Figure 3. As the ambient temperature around the casing increases then the magnesium strip 16 expands and buckles-see Figure 6B. At a predetermined temperature, the magnesium strip 16 will contact the casing 20 thereby completing the sensor circuit 30-see Figure 3.

Under default conditions when there is no completed sensor circuit 30 i. e. when the magnesium strip 16 does not contact the casing 20, then the control unit 6 is in an"ON WAITING"condition. In this condition, the control unit 6 (and its associated circuitry) is in a primed condition awaiting completion of the sensor circuitry 30, or an open circuit condition as a result of component failure (as will be

discussed in further detail below) to cause the pump/pump motor to activate and the sprinklers 2a, 2b to operate.

When the sensor circuit 30 is completed once the ambient temperature reaches the predetermined value, then the microprocessor 12 detects this, and is operable to time out a predetermined period of time-typically around 10 minutes- although this can be manually selected by a user. The sensor 9 can be designed to provide complete the sensor circuit 30 at different temperatures-typically between 40 and 60 degrees Celsius.

The effect of the detection of an completed sensor circuit 30 is to provide an"ON" condition, whereby signals are sent to, the pump motors 13 so that the pump motors 13 will operate thereby pumping water from the tank 4, through the sprinkler network 1 to the sprinklers 2a, 2b, and wetting down the building. After the predetermined period has timed out, then the microprocessor 12 is operable to determine if the sensor circuit 30 is still complete, i. e. that the ambient temperature is still above the predetermined threshold value. If this is so, then the "ON"condition is maintained the pump motors 13 will continue to operate and the microprocessor will continue to time out the predetermined period of time. This cycle will continue until such time as the ambient temperature is such that the magnesium strip 16 no longer contacts the casing 20 and the control unit 6 is once more placed in the"ON WAITING"condition.

The magnesium strip sensor 9 is already known to persons skilled in the art, and, as such, need not be described in any further detail herein. However, unlike known applications where such sensors are used to switch circuits to an"OFF" condition, for example, to prevent components overheating, in the present application, the sensor is used to switch the control unit 6 to an"ON"condition.

An LCD display 18 is also provided coupled to the microprocessor 12. This display 18 can be used to display information and/or error messages under control of the microprocessor 12-in a manner known to persons skilled in the art.

An LED 22 is used to provide illumination for the LCD display 18.

The microprocessor 12 is also operable to turn on the pump motors 13 at regular intervals for a predetermined period of time. For example, the pump motors 13 could be set to operate once a week for two to five minutes at a time-this shows that the sprinkler control system is working, and cleans and flushes the system.

The microprocessor 12 is also operable to detect loss of power from the battery 8, or damage to the sensors 9. Any break in the associated circuitry would provide an open circuit condition that would cause the microprocessor 12 to switch the control unit 6 to the"ON"condition. The third 26c of the three thermistors is used to detect any drop in potential due to faults in the component parts in the system, which causes the microprocessor 12 to switch the control unit 6 to the"ON" condition. When the control unit 6 is switched to an"ON"condition under operation of the microprocessor 12, the pump motors 13 are switched on and the sprinkler system 200 activated so that water is pumped through the piping and through the sprinklers 2a, 2b. In this way, the system 200 defaults to an"ON" condition when an error in operation is detected. In addition to the pump motors 13 being switched on, a signal is sent by the microprocessor 12 to the audible alarm 15, to provide an audible signal that the system is faulty. An error message can also be displayed on the LCD display 18-again under control of the microprocessor 12.

The microprocessor 12 could be provided with a wireless transceiver to allow it to be operated remotely, for example using wireless technologies such as pagers or cellular radio telephones.

In addition to temperature sensors, other sensors such as smoke detectors could be used.

Although the system of the present invention has been described with reference to a fire control system, it would be clear to a person skilled in the art, that this could be used for other suitable measures, such as frost prevention in vineyards and market gardens. In such example, the sensors would be used to detect temperatures below a certain threshold.

Any suitable water source can be used instead of, or in addition to, the water tank - for example dams or rivers.