NZ599385B - Fire Detection System - Google Patents

Abstract

Patent 599385 Disclosed is a fire detection system (FDS) with a master control board (4) configured to receive at least one signal and issue at least one command signal. The FDS includes at least one temperature sensor (3a, 3b, 3c) and at least one smoke detector (6). The FDS is configured such that once the at least one temperature sensor (3a, 3b, 3c) detects a temperature that reaches an activation point, the temperature sensor (3a, 3b, 3c) sends a signal to the master control board (4). The master control board (4), once the signal is received, is then configured to issue a command signal resulting in the activation of at least one smoke detector (6) to detect the presence of smoke. that once the at least one temperature sensor (3a, 3b, 3c) detects a temperature that reaches an activation point, the temperature sensor (3a, 3b, 3c) sends a signal to the master control board (4). The master control board (4), once the signal is received, is then configured to issue a command signal resulting in the activation of at least one smoke detector (6) to detect the presence of smoke.

Description

James & Wells ref: 133365/76 PATENTS FORM NO. 5 Fee No. 4: $250.00 PATENTS ACT 1953 COMPLETE SPECIFICATION Fire detection system We, TLC Enterprises Limited a New Zealand Company of 987 Tuhikaramea Road, RD10, Hamilton 3290, New Zealand; Jarna Joy McLachlan a New d citizen of c/— James & Wells Intellectual Property, Level 12, 85 Alexandra Street, Hamilton 3204, New Zealand; Glen Richard McLachlan a New Zealand citizen of c/- James & Wells Intellectual Property, Level 12, 85 Alexandra Street, on 3204, New Zealand hereby e the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: James & Wells ref: 133365/76 Fire detection system TECHNICAL FIELD The invention relates to a fire detection system, and particularly, but not limited to, use with a kitchen rangehood extractor system.

BACKGROUND ART The majority of fires starting in the kitchen originate at the cooking t (or hob), according to recent tical information ble in New Zealand.

Such fires typically begin from ignition of cooking oils during the g process, rtent placement of tea towels on a hot element, or from ts/ovens accidentally being left on which then can result in food eventually combusting. The ty of these fires are caused when the cooking station has been left unattended.

In order to circumvent such fires with often disastrous consequences, rangehoods with built in fire suppression systems have been developed. These are intended to control the fire at the source well before the fire has had a chance to spread and be identified through distantly located smoke/fire detectors. Often by this stage the fire has grown out of control.

For example, many commercial kitchens have been custom built with self extinguishing rangehoods. They operate using glass fuses which are set to melt at a specific temperature, releasing mechanical rubber belts and springs which then ultimately remove a pin from a fire extinguisher to e the suppressant therein. Such systems have also been retrofitted to residential oods. However, due to the mechanical nature of such systems they can be a also to maintain, replace or repair. very expensive process not only to set up, but In other cases, hanging fire uishers have been developed to be used with rangehoods.

Such devices are small cans with a loop at the top for hanging the can from the rangehood.

The bottom of the can is mechanically ed so that in the event of a fire, the base of the can drops away, releasing suppressant which is stored inside.

A further system described in US 5,335,026 is a fire suppression system whereby increased heat from a fire results in melting of an insulator material which is present around two twisted wires, resulting in a short-circuit condition being ed. This event can result in an alarm being sounded as well as increased voltage across the actuator to the effect that the actuator cuts a tension wire leading to fire suppression fluid being released on to the fire.

However, there are considerable disadvantages to the systems discussed above.

James & Wells ref: /76 y, they all rely y on mechanical devices to initiate a response. Such activation through devices such as rubber belts has a tendency to loose their iveness, especially in the kitchen environment. rly, springs are known to loose their recoil ability when held under tension for long periods.

These disadvantages result in lower trust from the user, potential lower reliability and higher maintenance requirements to ensure safety.

A further disadvantage of such systems is that due to faulty parts or inaccurate readings, false alarms or release of suppressant may eventuate when not ed, not required or not necessary. This is generally enient as it requires replacement and maintenance of parts, well as as well as potentially damage to the stove top, cooking appliances such as pots, as spoiling the food potentially being prepared at the time of the incident. rmore, it can be ult to detect fires within a rangehood because steam can trigger most fire detectors in a domestic kitchen environment.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not tute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

Throughout this specification, the word "comprise", or variations f such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, r or step, or of any other element, integer or step, group of elements integers or steps, but not the exclusion or group of elements, integers or steps.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

James & Wells ref: 133365/76 DISCLOSURE OF THE INVENTION According to one aspect of the present invention there is provided a fire detection system; characterised in that the system includes at least one temperature sensor; and at least one smoke detector detects a wherein the system is configured such that once the at least one temperature sensor smoke ature that reaches an activation point, the system activates the at least one detector to detect the presence of smoke. which According to another aspect of the present invention there is provided a rangehood includes a fire detection system as substantially discussed herein.

According to r aspect of the present invention there is provided a fire detection apparatus; characterised in that the system includes at least one temperature sensor; and at least one smoke detector wherein the apparatus is ured such that if the at least one temperature sensor detects a smoke temperature that s an activation point, the apparatus activates the at least one detector to detect the presence of smoke. fire According to r aspect of the present invention there is provided a method of using a the steps ion system as discussed herein with a rangehood, wherein the method includes a) detecting a temperature of the environment near the rangehood with at least one temperature sensor and b) activating at least one smoke detector to detect the presence of smoke if the at least one least one temperature sensor s an activation point, the apparatus activates the at smoke or. which ing to another aspect of the present invention there is provided a kitset of parts includes: a) a fire detection apparatus or system as described herein b) a rangehood; James & Wells ref: 133365/76 c) and optionally a fire suppression system.

ADVANTAGES OF THE PRESENT INVENTm - Avoids the need to constantly measure for smoke in an area that often will present smoke but potentially without the risk for fire.

- If a temperature threshold is d that indicates a potential for fire, the smoke detector is then only activated to confirm presence of fire or potential for fire. Therefore, alarm activation and/or deterrent effect may only be ted if and when a serious threat of fire is present.

- Lower requirement for smoke detector activation means higher quality smoke ors 1o (e.g. laser detectors) are practical to use. Otherwise, continual use of such detectors would be costly and/or may soon break down.

- An signal output (or ion”) indicating a) no fire, b) fire, or 0) potential for fire from the smoke or may be significantly more accurate (illustrating a synergistic effect) than just one type of sensor. This is because the “decision” on a fire being present has passed criteria for both temperature and smoke indicative of a fair.

- Downstream s (as discussed hout the specification) therefore present a plethora of advantages over known systems.

- For example, one can avoid: 0 false alarms more often, o faulty smoke detectors due to overuse, o unnecessary deployment of fire ssant, leading to wasted suppressant, ruined food and damage to stove, requirement to replace spent canisters or new systems following false /unnecessary ment. 0 Failure of identifying a true fire.

Further advantages of the present invention will become apparent with the ensuing description and discussion of the preferred embodiments.

PREFERRED EMBODIMENTS Fire detection system Throughout the present invention the phrase fire detection system (herein termed FDS) should be ered any device, apparatus (either singular or multiple) that provides a system to allow the detection of a fire or potential for fire (e.g. through detection of increased heat and smoke).

James & Wells ref: 133365/76 Preferably, the FDS is in communication with a ood located in the vicinity of a cooking element. For example, the inventor sees the significant commercial application wherein the invention forms part of a typical rangehood located directly above a stovetop, where kitchen fires most often arise. Therefore, ation directly at the source of the fire gives an ed chance of stopping the fire early, avoiding damage and saving lives.

Throughout the remainder of the specification, reference to the FDS is made particularly in relation to use in or with a rangehood. However, this should not be considered limiting, as the present invention is envisaged to have other applications beyond rangehoods, such as in heavy machinery engine bays, yachts/large vessels that may not have a rangehood but the fire detection system may be placed in an enclosure above the g area, vans, etc.

Rangehood Preferably, the ood includes a master control board.

The master l board may include a circuit able to identify a temperature activation point suggestive of a fire or potential for fire.

For instance, the circuit may be able to take readings to calibrate each rangehood (e.g. during installation or during a service) to identify normal baseline temperature and therefore calculate a “moving" activation point (for instance a set temperature above the base line). Therefore, the invention may be easily ble to ent rangehood models (which may vary on aspects such as fan strength or dimensions), as well as fluctuations in climate temperatures etc.

Also, fan speed may lead to automatic adjustment of the activation points. Potentially, if the fan stops working (or is faulty), this could also change the airflow - this, and other variants of temperature, may be accounted for through ment (manual or automatic) of the activation point.

Preferably, the master control board is configured to t for fan speed in the rangehood when setting and/or ing the activation point.

The rangehood may include any one or combination of functions below: - Fan speed up/ fan speed down controls, - Multiple speed fan settings — Lighting - User display panel James & Wells ref: 133365/76 - Fire suppressant canisters or suppressant delivery system tially as part of the FDS). Such canisters may be replaceable. Substantially any fire suppressant may be used and should not be considered outside the scope of the invention Preferably, the FDS is configured to integrate into an existing hardwired or wireless fire alarm system.

This may be advantageous to bring the attention of the fire/potential fire to the appropriate person/people faster and more effectively. For instance, the FDS may be integrated with an external communication system, such as the Fire Department or friend’s / relative’s house. This may be particularly beneficial for the elderly.

The fire detection system may also n a wired or wireless control system allowing the isolation of either the gas or electrical supply to the cooking device.

Motion sensor Preferably the FDS includes a motion sensor.

The motion sensor has us applications and works synergistically with the ature and smoke detectors to provide significant ages.

For example, the motion sensor may be activated upon use of the stovetop, such as turning on a heating element. In one embodiment, if no movement is observed from the motion sensor within a given period of time, an alarm may be activated to remind the user that cooking is in if negligence continues. Such negligence is progress, and there is a danger of a fire developing a leading cause of n fires.

The motion sensor may even be configured to issue a command signal to the master control board to vate the g element if no movement is seen within a given period of time.

The motion sensor has further applications. For example, if no movement is observed within a given period of time after cooking has begun, the FDS may be configured to activate the smoke detector without an activation point being reached. This ment could represent a significant age to help detect and register a fire/potential fire sooner than if just a temperature sensor is being used to reach the activation point.

Temperature sensor Preferably, the FDS includes a plurality of ature sensors.

Most preferably there are three temperature sensors spaced apart in the underside of a rangehood. In an alternative embodiment, the temperature sensors are incorporated into the splashback.

James & Wells ref: 133365/76 The inventors envisage the temperature sensor may be a positive temperature coefficient (PTC) thermistor or negative temperature coefficient (NTC) thermistor.

The PTC/NTC may be preferable due to their low cost, high bility and reasonable accuracy.

For example, the temperature sensors may be configured to detect temperatures as follows: a) primary sensor to detect temperature above 40°C; b) secondary sensor to detect temperature above 65°C; and c) ry sensor to detect temperature above 100°C.

In such an embodiment, the primary sensor may be sufficient to detect that the stovetop is in Of course, variations on use, and thus activate the movement detector (as discussed . this embodiment are possible and should not be considered outside the scope of the invention.

The atures exemplified above are merely for examples, and could be adjusted to substantially any temperature, as discussed below.

Such variations may be due to differences in setup. For example, one rangehood may be located opposite a large window with full sun all day long and another may be in a cool part of the house. This may result in temperature readings to vary on every install.

This This primary sensor may also be useful to automatically activate the fan of the rangehood. summer. may be advantageous for g the kitchen temperature during The ary sensor may be configured to send a signal to the master l board to activate the smoke detector if its temperature set point is reached. filters of For example, the inventors have observed that the ork inside and near the main the rangehood may warm to approximately 65-75°C when a fire is present. However, this change in temperature is dependent on the fan speed, and ially many other variables.

The tertiary sensor may be used to determine significant risk of fire and, potentially in combination with verification from the smoke detector once activated, send a signal to the master control board resulting in a command signal to lead to dispersion of a suppressant on a fire (discussed in more detail below).

Furthermore, the temperature sensors may be configured to measure certain components of rangehood structure opposed to the air ling through the rangehood. take As discussed above, the inventors ge the temperature sensors may be configured to into account such variables such as ound temperature, size/configuration of the James & Wells ref: 133365/76 rangehood, sensor position and the airflow cooling effect provided from the fan in the rangehood.

In another embodiment. readings from multiple temperature sensors may improve accuracy of the readings by providing an average. An average can ent a more accurate reflection on whether a fire is present or imminent. The average temperature reading may be used to initiate an activation of the smoke or instead of a single temperature sensor.

Activation point The inventors envisage that once the tion point of the temperature sensor(s) has been reached, the FDS may be configured to send a signal to the master control board, which then results in a command signal to activate the smoke detector.

As discussed above, the activation point may be ent on numerous variables. The activation point may be fixed, adjustable, or be constantly changing dependent on key inputs from the surrounding environment (e.g. room temperature) or FDS (e.g. fan speed).

The tion point may be an e of multiple temperature sensors. Alternatively, it may be a temperature of just one specific temperature sensor, for instance the secondary temperature sensor.

Smoke or Preferably, smoke detector is a high quality smoke detector. For example, a smoke detector employing a laser may be well suited to the present invention. Of course, other smoke or types such as traditional ionization or photoelectric styles may be used. The present invention should not be limited to the type of smoke detector used.

One advantage of the present ion is that e the smoke detector is not required to be continuously activated, a higher quality detector may be used to increase sensitivity and accuracy without significant concern about overuse etc.

Once the smoke detector has been activated, different ments of the present invention are envisioned by the inventors.

Preferably, if the smoke detector detects smoke the FDS may include any one or combination of the ing functions (in any order): a) warn audibly h an alarm; or b) send a command signal from the master control board to the motion sensor to detect the fire); or presence of movement (potentially equating to the user addressing James & Wells ref: 133365/76 0) send a command signal from the master control board to result in the rangehood fan (if operating) to stop — to prevent excess oxygen flow to the potential fire; or d) send a command signal from the master control board to result in dispensing of suppressant. e) Send a command signal from the master control board to result in turning off the cooking element/oven.

For b), an infrared beam may be used to detect movement. Alternatively, standard conventional detectors such as PIR sensor may be used.

For d), the dispensing of suppressant may be halted as a result of detected movement and/or a keypress button is pressed. This may indicate the user has returned to control the fire. smoke and/or high temperature is still detected after a given time period after the users with fire suppression release. This may response, the system may be ured to continue cover the option where the user was unable to control the fire.

Of course, such embodiments are merely examples of software options. Alternative embodiments should not be considered outside the scope of the invention.

For a lower cost cial model, the inventors ge that options a) and b) may be configured as part of the FDS in the ood. A more high specification commercial model may e all of options a) - e).

The embodiments ed above may help contribute to the significant advantages of the present invention, some of which e: - greater safety and greater accuracy due to synergic interaction of different detector/sensor types; - lower chance of unnecessary damage to rangehood, stovetop, and/or food as a result of releasing suppressant when not required; - avoiding ssary usage (and therefore replacement) of suppressant. — providing a user friendly, preferably automated, fire detection system to avoid kitchen fires, and if ary (once specific criteria are met) the release of suppressant and/or additional measures to control/stop the fire.

- Options for user manual override if preferred.

James & Wells ref: 133365/76 BRIEF DESCRIPTION OF THE DRAWINGS Further aspects of the present invention will become apparent from the ensuing description which is given by way of example only and with reference to the accompanying drawings in which: Figure 1 shows a schematic representation of the F08 integrated into a rangehood; BEST MODES FOR CARRYING OUT THE INVENTION As rated in the schematic representation in Figure 1, the fire detection system (FDS) is to be integrated into the underside of a rangehood (not shown). Typically the rangehood (2) will be placed above a cooking element such as on a conventional oven (not . 1O The rangehood (2) includes a main control board (4) with a circuit board (not shown). The main control board (4) is configured to receive signals from ent elements of the FDS, and then issue command signals to result in the appropriate action being taken, as sed further below.

The rangehood (2) includes, as part of the FDS, three PCT/NTC thermistor temperature sensors (3 A-C) which are spaced apart. A primary sensor (3 -A) is ured to detect temperatures above 40°C, a secondary sensor (3 -B) is configured to detect atures above 65°C, and a third sensor (3 -C) is configured to detect temperatures above 100°C.

When a temperature sensor (3) detects a temperature at or above the “activation point” it sends a signal to the main control board (4).

A signal ation point being reached) from primary sensor (3-A) results in the main control board (4) sending a command signal to a motion sensor (5) to activate. This indicates the cooking element is in use.

The motion sensor (5) will then scan for movement. If no movement is fied within two minutes, an audible alarm will issue to remind the user that the cooking element is in use to avoid fires from beginning. This will continue until movement is again seen.

In one embodiment, if the motion sensor (5) identifies no movement within a five minute period, it will automatically bypass the activation point of from the secondary sensor (3-B) to result in the smoke or (6) activating to detect the presence of smoke.

A signal (activation point of 180°C being reached) from the secondary sensor (3-B) results in the main l board (4) sending a command signal to result in the smoke detector (6) to activate to detect the presence of smoke.

If smoke is detected by the smoke detector (6), an alarm will sound to alert the user (and/or third party) that there is a fire or potential for fire.

James & Wells ref: 133365/76 A signal (activation point of 200°C being reached) from the tertiary sensor (3-0) will result in the main l board (4) sending a command signal to result in release of suppressant from a canister (not shown) on to the fire.

Signals from either the smoke detector or temperature (s) may also result in any one of the following actions olled through the main control board): a) Re-activate motion sensor (5) to detect presence of the user addressing the fire; or b) Stopping the rangehood fan (if operating) to prevent excess oxygen flow to the potential fire; or c) Dispensing of suppressant (which could be halted due to manual override by user or as a result of movement detected by motion sensor (5); or d) Turning off the cooking elementjoven.

The activation points of the temperature sensors (3 A-C) are able to be calibrated at any time to allow them to account for alterations in variables such as differences in rangehood models, base line temperature, fan speed, filter efficiency etc. These are software functions which someone skilled in the art would understand how to ent. Furthermore, the activation points are configured to be automatically adjusted due to variations over the short term period, such as when a user adjusts the fan speed.

The FDS of the present invention may be retrofitted into a ood (2) or built in during manufacturing.

Aspects of the present invention have been described by way of e only and it should be appreciated that modifications and ons may be made thereto without departing from the scope f as defined in the appended claims.

James & Wells ref: 133365/76

Claims (8)

WHAT WE CLAIM IS:

1. A fire detection system (FDS) wherein the FDS includes a master control board ured to e at least one signal and issue at least one command signal, and wherein the FDS also includes at least one temperature sensor; and at least one smoke detector; characterised in that the FDS is configured such that once the at least one temperature sensor detects a temperature that reaches an activation point, the temperature sensor sends a signal to the master control board; and wherein the master control board, once said signal is received, is then configured to issue a d signal resulting in the activation of at least one smoke detector to detect the presence of smoke.

2. The FDS as claimed in claim 1 wherein the FDS is incorporated into a rangehood.

3. The FDS as claimed in claim 2 wherein the FDS includes at least one supply of fire suppressant.

4. The FDS as claimed in claim 3 wherein the master control board is configured to be calibrated either manually, automatically at set time points, or uously or as a result of changing environmental conditions.

5. The FDS as d in any one of the above claims wherein the FDS includes a motion sensor.

6. The FDS as claimed in claim 5 wherein the motion sensor is activated as a result of use of a cooking element in the vicinity of the FDS.

7. The FDS as claimed in any one of the above claims n the FDS includes a plurality of temperature sensors.

8. The FDS as claimed in any one of the above claims wherein the FDS es three temperature sensors, each configured to have different activation points. James & Wells ref: