AU763877B2 - Improvement to smoke alarms - Google Patents

Description

1 IMPROVEMENT TO SMOKE ALARMS FIELD OF THE INVENTION The present invention relates to an environmental alarm apparatus and system for use in detecting environmental conditions, particularly fires and smoke, and the activation of such smoke alarm units.

BACKGROUND TO THE INVENTION It is common in present day smoke alarm units to incorporate a power supply derived from the standard mains supply, for example 240V an internal backup battery for example a 9V d.c. battery, a smoke detection sensor unit, typically of photoelectric or ionisation design, and a sounder. Such units provide terminals for connection of the mains supply.

Typically in large buildings there may be several different types of detection apparatus, such as smoke detectors and heat detectors, as well as alarm apparatus interconnected to an alarm supervisory board. Such a board will typically monitor the detectors throughout the building and upon locating a positive detect signal, the board will appropriately activate the alarm apparatus. A typical alarm apparatus in an apartment building consists of sounders in the building's corridors connected to the supervisory board. Such an alarm system, however, may only be activated via the centralised control of the alarm supervisory board. Such supervisory panels include expensive apparatus and are S generally expensive to install and maintain. The system is also complex and inflexible as all instructing communications are initiated by the supervisory panel.

An additional problem that confronts the designer of a fire alarm system is S: 25 that it is highly desirable that in large buildings, particularly apartment buildings, the alarms be activated, not only where the fire is initially detected but throughout the entire building so that the occupants in their own occupancy, rooms or units will have the necessary early warning. The early warning provides for additional time to evacuate the building.

30 A prior art smoke detection and alarm system for use in e.g. an apartment building is illustrated in Figure 5. The system includes one or more smoke detectors 60, a fire indicator supervisory panel 61, and separate alarm sounders 62. The smoke detectors 60 may be interconnected, and are adapted to send a 2 signal back to the fire indicator supervisory panel 61. The sounders 60 are in turn adapted to receive a signal from the fire indicator supervisory panel 61. Upon receiving a smoke detect signal from any one or more of the smoke detectors fire indicator supervisory panel 61 is able to activate the sounders 62 throughout the building. However, due to the expense of installation and wiring, and the requirement for the detectors 60 and sounders 62 to be compatible with the fire indicator supervisory panel 61, in a typical installation the detectors 60 and sounders 62 are installed primarily within the building's corridors.

Conventional domestic smoke alarms may be installed within individual apartments to provide additional protection to residents in the case of a fire within their own apartments. However, when smoke is first detected elsewhere in the building, and as a typical prior art warning system in an apartment building, such as that shown in Figure 5, consists of sounders in the building's corridors connected to a supervisory board, the system is not always effective in alerting the building's occupants, particularly if they are sleeping, due to the sounders being external to the occupant's room or unit.

US Patent No. 5,587,705 addressed these problems by providing a smoke alarm that operates with other smoke alarms of the same design by communicating an alarm directly to other smoke alarms, without the need of an intermediary fire supervisory panel. In this patent, communication is initiated by an alarm which senses smoke. That alarm sounds its own sounder and sends a radio signal of a certain frequency to other nearby alarms tuned to that frequency.

The alarms that receive the radio signal emit a pulsed alarm to act as an early warning system for occupants of the building remote from the initiating smoke 25 alarm.

The system described in US Patent No. 5,587,705, while attaining decentralised control still lacks a degree of flexibility, particularly since only alarms within radio receiving distance are able to be simultaneously sounded, and also because the alarms are only able to communicate with other compatible 30 alarms. This last point means that there would be considerable expense to installing such alarms in a building, as all alarms would need to be of the same type to have an effective system. Furthermore, by using interconnected smoke alarms only, the additional benefits of having a centralised fire indicator supervisory panel, such as being able to sound the alarms in response to other events, or being able to operate other external devices such as a sprinkler system or protective fire doors in response to a smoke detect alarm.

It is therefore an object of the present invention to provide an alarm unit that provides enhanced flexibility in its ability to communicate with other devices.

It is a further object of the present invention to alleviate at least one problem of the prior art.

SUMMARY OF THE INVENTION The present invention provides an environmental condition detection alarm unit including: a sensor; a sounder; mains power terminal connections; a detect input/output terminal adapted to interconnect with one or more other alarm units; and a fourth terminal adapted to be in communicable relation with one or more external devices; wherein the sounder is adapted to be activated upon receiving an activation signal via any one of the sensor, the detect I/O terminal or the fourth terminal.

The environmental conditions that such a unit may detect include smoke, heat, movement or even a particular harmful gas.

Thus, in various system configurations incorporating the alarm units, the units are able to receive initiating signals from an external source as well as other 25 alarms. Examples of external sources which are able to initiate a signal to the smoke alarm units are a compatible sprinkler system or even an alarm supervisory board. In the example of the alarms being in communicable relation with the alarm supervisory board it is possible to gradually introduce these alarms into a building's detector system and still remain compatible with other alarms, as 30 the board could act as an intermediary.

further advantage is that the fourth terminal may be used as an output to operate external devices, such as an additional external strobe or siren.

o BRIEF DESCRIPTION OF THE FIGURES Figure 1 depicts a block diagram of a smoke alarm unit according to an embodiment of the present invention.

Figure 2 depicts the interconnection of three smoke alarm units the same as the one shown in Figure 1.

Figure 3 depicts a first arrangement of three smoke alarm units the same or similar to the one shown in Figure 1, and an alarm supervisory board.

Figure 4 depicts a second arrangement of the three smoke alarm units and an alarm supervisory board.

Figure 5 depicts an arrangement of prior art smoke alarms, and an alarm supervisory board.

DETAILED DESCRIPTION Referring now to Figure 1 there is depicted a schematic diagram of a smoke alarm unit according to a preferred embodiment of the present invention.

Mains power enters power converter 5 at active terminal 1 and neutral terminal 3. The power converter converts the mains power to approximately on power rail 15 which is used to power the alarm unit. Green LED 17 is connected to power converter 5 and lights when said converter is operating normally to visually indicate that the AC mains power is connected and the smoke alarm unit is operational. The unit includes a disposable backup battery 7 which is connected to battery monitor module 13 and to the anode of diode 11. The cathode of diode 11 is connected to the output of power converter 5. By virtue of the connection of backup battery 7 via diode 11 to power rail 15 the battery provides a power backup in the event that mains power or power converter 25 fails.

Battery monitor module 13 is further connected to yellow LED 19 which is lit by battery monitor module 13 if the voltage of battery 7 falls below a threshold level. Consequently an alarm unit with a failed backup battery may be readily identified by visually identifying the alarm unit with a lit or flashing yellow LED.

30 This feature may be used particularly with ionisation-type smoke alarms and .i photoelectric type smoke alarms with replaceable or rechargeable batteries. The visual indication may be used as the sole indication of the battery levels, or in conjunction with an audible "chirp" indication.

The alarm unit further includes a digital logic chip 21 which monitors the detector module 23. This detector is most preferably a smoke or fire detector, but it is equally possible that the detector may be used to detect other conditions, such as a particular gas or even movement. In the embodiment of the detector being a smoke or fire detector, the detector module 23 generates a signal in the event of smoke or heat being detected. The operation of detector module 23 when detecting smoke may be emulated by depressing test button 29 thereby commanding test generator 30 to send an emulated smoke detect signal to logic chip 21.

The logic chip 21 is also adapted to receive an activation signal from the detect I/O terminal 27 and to be able to send a signal, also via the detect I/O terminal 27.

A fourth terminal 4 is provided in order to enable the alarm unit to communicate with a range of external devices. The fourth terminal 4 provides an additional local signal source that enables the alarm unit to communicate with one or more external devices. In the preferred embodiment, the fourth terminal 4 is connected to a fixed internal reference signal of the alarm unit, being a terminal of the backup battery 7. Communication with one or more external devices may then be achieved via indirect connection of the fourth terminal 4 with the logic chip 21, in conjunction with the detect I/O terminal 27.

The operation of the smoke alarm unit of Figure 1 will now be described.

Upon sensing a smoke detect signal from smoke detect module 23, logic chip 21 sets bi-directional detect I/O terminal 27 to a particular logic level (eg a high level represented by a potential of +9V) to indicate the smoke detect signal and 25 accordingly the presence of a fire. Red LED 25 is then latched high so that it will not deactivate even after the smoke detector module 23 no longer generates a smoke detect signal. The latch may be either part of alarm LED control module 24 or alternatively be incorporated into logic chip 21. Logic chip 21 also activates buzzer 31.

30 The buzzer continues to sound until the signal from smoke detector module 23 indicates that smoke is no longer detected, at which point logic chip 21 de-activates buzzer 31, and deactivates the signal on detect I/O terminal 27. The red alarm LED 25 remains lit for a period after the buzzer is deactivated.

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6 Typically, the period for which LED 25 remains lit is approximately five minutes.

Maintenance of the alarm LED 25 in the lit state during this period may be achieved using circuitry incorporated into the alarm LED control module 24 or alternatively this function may be implemented within logic chip 21.

The detect I/O terminal is adapted to be connected to corresponding detect I/O terminals of other compatible alarm units. Therefore, by setting the detect I/O terminal of the figure 1 alarm device high when smoke is detected, any connected alarm units are notified of the detection of a fire, which results in their own alarms being initiated so as to act as an early warning alarm to occupants in other parts of the building. Conversely, the smoke alarm of figure 1 is able to receive a signal from another remote alarm unit and sound its alarm as an early warning device.

These features will be discussed in more detail shortly, particularly in relation to figure 2.

If the logic chip receives an activation signal from the detect I/O terminal 27, it activates the buzzer 31. In this situation, it is also possible that the "early warning" buzzer is different to that of the "initiating alarm" buzzer, so that occupants of the building may aurally determine whether their alarm is the initiating alarm or whether the alarm is an early warning alarm.

Figure 2 further illustrates the operation of multiple alarm units according to the present invention when interconnected in a manner known from the prior art via the detect I/O terminal 27. The alarm units A, B, C, are the same as the alarm o. unit depicted in Figure 1, so the same reference numerals will be used in this description. The detect I/O terminals of all three alarm units are connected together by cable 33. The I/O detect terminals 27A, 27B and 27C are adapted to 25 operate in a "wired-OR" configuration, so that any alarm unit may set the alarm condition to be signalled via cable 33. In the event that a fire occurs nearest to an alarm unit, for example unit A, the smoke detector module in that unit will sense the associated smoke and generate a detect signal. The logic chip 21A of unit A will signal the detect condition to the other units A and C by setting detect I/O 30 terminal 27A high. It will also latch red alarm LED 25A and activate buzzer 31A.

Upon the detect I/O port 27A of logic chip 21A being set high the bi-directional logic ports 21 B, 21C of the logic chips in alarm units B and C respectively will also go high by virtue of their connection to cable 33. Upon the logic chips in units B and C detecting the alarm state at their bi-directional detect I/O terminals 27B, 27C, they will activate their buzzers 31 B, 31 C respectively.

Subsequently, at such time when smoke detector module 23A in alarm unit A is no longer in a smoke detect state, logic chip 21A will return I/O terminal 27A to low, so that the connected bi-directional detect I/O terminals 27B and 270 will also fall low. The logic chips in all units also deactivate their respective buzzers.

However, the alarm LED 25A in unit A will remain lit, for example for approximately five minutes, thereby indicating to an observer that it is the unit from which the first alarm signal originated. In this way the originating alarm is conveniently identified even after the alarm units have ceased sounding and without the need for complex wiring.

In an alternative embodiment, when smoke is detected at unit A and the logic chips in units B and C detect the alarm state at I/O terminals 27B, 270 thereby activating their buzzers, their alarm LED's 25B, 250 may also be activated, but not latched. Therefore, when the signal at the I/O terminals falls low, deactivating the buzzers, the alarm LED's 25B and 250 will also be deactivated leaving only the alarm LED 25A of unit A lit for a pre-determined time in order to indicate the unit which originated the alarm signal.

In Figures 3 and 4 the smoke alarm units are illustrated as integrated in a building's warning system. This is achieved through the provision of a fourth terminal" (indicated on each unit in Figure 3 by the references 4D, 4E and 4F) and connecting these terminals either directly or indirectly to an external device.

An example of an indirect connection to an external device is via an alarm supervisory board. This configuration is illustrated in both Figures 3 and 4.

25 Referring now to Figure 3 there is depicted an arrangement of three smoke alarm units D, E, F of the type the same or similar to that shown in Figure 1, and an alarm supervisory board 41 interfaced to each of the alarm units by means of three normally open open when de-energised) relays 45, 46, 47. According to the present invention alarm units D, E, F, may be conveniently activated by the 30 alarm supervisory board 41. This capability is achieved by provision of the externally accessible +9V "fourth" terminals 4D, 4E, 4F in each alarm unit.

~In the event of supervisory board 41 being notified of a hazard by an l."external device, by means of one or more of its connections 49 for example, it i may decide to activate alarm units D, E, F. Activation of the alarm units is achieved by passing a current through relays 45, 46 and 47. This current energises the relay coils in relays 44, 46 and 47 and so closes switches 50, 51 and 52 thereby connecting detect I/O terminals 27A, 27B and 27C to their respective "fourth" terminals 4D, 4E and 4F. Consequently, each of alarm units D, E, F will enter an alarm state. It should be noted that none of the alarm units will latch their alarm LEDs 25D, 25E, 25F, as in a preferred embodiment, latching only occurs in an originating alarm unit and in the present case the alarm signal does not originate in any of the alarm units.

It is to be noted that in the Figure 3 embodiment, all of the alarm units D, E, F are in parallel with the alarm supervisory board 41 and the alarm units are not interconnected (ie the I/O detect terminals of each alarm unit are not directly connected to each other). This therefore means that the alarm units work independently as smoke alarms and will only activate if an activation signal is sent by the alarm supervisory panel.

Although not shown in Figure 3, it is to be noted that while each alarm unit D, E and F is not able to activate the other alarms as an early warning system, they are each capable of sending a signal to the alarm supervisory panel 41 if the relay units 45, 46, and 47 respectively are adapted to receive and forward signals from the alarm I/O terminals of the alarm units, notifying the panel of the existence of a fire, which is in turn able to activate external devices, such as sprinkler systems or additional external strobes or sirens.

Referring now to Figure 4 there is depicted a further arrangement of a supervisory board 41 and three alarm units G, H, J. the same or similar to the unit S 25 of Figure 1. By this arrangement one relay 55 is used to interface only one alarm unit, being alarm unit G. A common wire 33 interconnects detect I/O terminals 27G, 27H and 27J. In the event of supervisory board 41 determining that a smoke alarm condition exists it energises the coil of relay 55 thereby closing switch 57 and connecting detect I/O terminal 27G to the fourth terminal 4G. As a result logic S 30 chip 21G recognises an alarm state and activates buzzer 31G and, optionally, alarm LED 25G. As detect I/O terminal 27G is wired to detect I/O terminals 27H and 27J by cable 33, alarm units H and J similarly enter an alarm state. While l..

each alarm unit may illuminate their alarm LEDs, none of the alarm units latch their alarm LEDs because the alarm command originates at supervisory board 41 rather than in any of alarm units G, H, J.

It is to be noted that a difference between this Figure 4 embodiment and that of Figure 3, is that the alarm units are interconnected in this embodiment.

Therefore in this example, if alarm unit G detects smoke, it activates the other interconnected alarms H and J.

Therefore, considering all of these examples and embodiments it is apparent that the combination of the I/O detect terminal and the fourth terminal provides each smoke alarm with enhanced flexibility in arranging suitable configurations.

In particular, when smoke alarm units according to the present invention are installed within eg individual apartments within an apartment building, it is not only possible to interconnect groups of smoke alarm units so that the can sound their alarms together in response to any one or more units' detecting smoke, but it is also possible to connect one or more units to a fire indicator supervisory panel.

The fire indicator supervisory panel is then able to activate the smoke alarms within a plurality of individual apartments in response to an alarm raised on any one or more of its inputs, thus providing a more effective early warning system to residents throughout the building. Furthermore, since the activation of the alarms is facilitated using the fourth terminal, the system may be readily adapted to be compatible with a wide range of fire indicator supervisory panels and other external devices.

o As smoke alarm units according to the present invention do not need to be compatible with existing fire supervisory panels or other external devices, it is S 25 possible to upgrade an existing system without the need to replace or upgrade any existing components of the system. This is particularly beneficial where a building with an existing system requires upgrading with additional smoke alarms in order to continue to satisfy fire and safety regulations The invention is not limited to any particular form but rather it will be 30 apparent that the details of the embodiments described above may be varied to meet different requirements. For example, the fourth terminal of the alarm unit need not be hard-wired via a relay to an external device. The only requirement is a a that the fourth terminal is capable of being in communicable relation with one or more external devices.

Further, alternative arrangements of alarm units are possible, including other configurations incorporating alarm supervisory boards or directly connected to one or more external devices.

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Claims (11)

1. An environmental condition detection alarm unit including: a sensor; a sounder; mains power terminal connections; a detect input/output terminal adapted to interconnect with one or more other alarm units; and a fourth terminal adapted to be in communicable relation with one or more external devices; such that the sounder is adapted to be activated upon receiving an activation signal via any one of the sensor, the detect I/O terminal or the fourth terminal.

2. The environmental condition detection alarm unit of claim 1 wherein the environmental condition to be detected by the alarm unit is smoke.

3. The environmental condition detection alarm unit of claim 1 or 2 wherein the fourth terminal is in communicable relation with the one or more external devices via an alarm supervisory panel.

4. The environmental condition detection alarm unit of any one of claims 1 to 3 wherein the fourth terminal is adapted to send a signal to the one or more external devices when a positive detection is made by the alarm unit, as well as receive activation signals from at least one of the one or more external devices. The environmental condition detection alarm unit of claim 3 wherein the fourth terminal is adapted to send a signal to the one or more external devices when a positive detection is made by the alarm unit, as well as receive activation signals from the alarm supervisory panel.

6. The environmental condition detection alarm unit of claim 1 or 2 wherein communication with the one or more external devices is effected by electrical connection of the fourth terminal to a first contact of a switch and electrical 12 connection of a second contact of the switch to the detect input/output terminal and where electrical operation of the switch is effected by the one or more external devices.

7. The environmental condition detection alarm unit of claim 3 wherein communication from the alarm supervisory panel to the alarm unit is effected by electrical connection of the fourth terminal to a first contact of a switch and electrical connection of a second contact of the switch to the detect input/output terminal such that electrical operation of the switch is effected by the alarm supervisory panel.

8. The environmental condition detection alarm unit of claim 6 or 7 wherein the switch is a relay.

9. An alarm system including one or more environmental condition detection alarm units as claimed in any one of claims 1 to 8. The alarm system of claim 9 wherein the one or more environmental condition detection alarm units are interconnected via their respective detect I/O terminals.

11. A method of providing an early warning alarm within an alarm system including one or more environmental condition detection alarm units according to Sclaim 5 including the steps of: receiving an alarm condition signal at the alarm supervisory panel; communicating the alarm condition from the alarm supervisory panel to the one or more environmental condition alarms via the fourth terminals of the one or more environmental condition alarms.

12. A method of providing an early warning alarm within an alarm system S, including one or more environmental condition detection alarm units according to claim 7 including the steps of: *receiving an alarm condition signal at the alarm supervisory panel; ",,--"receiving an alarm condition signal at the alarm supervisory panel; S 13 communicating the alarm condition from the alarm supervisory panel to the one or more environmental condition alarms by operating the switch.

13. A method of providing an early warning alarm within an alarm system including one or more environmental condition detection alarm units according to claim 8 including the steps of: receiving an alarm condition signal at the alarm supervisory panel; communicating the alarm condition from the alarm supervisory panel to the one or more environmental condition alarms by energising the coil of the relay. DATED this 14 th day of May 2003 PSA PRODUCTS PTY LTD AND FYRNETICS (HONG KONG) LTD WATERMARK PATENT TRADE MARK ATTORNEYS 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA P16060AUPC NWM/MAS/RES a