SPRINKLER BULB

Abstract

A sprinkler bulb 100 for a fire suppression system and a method of activating the sprinkler bulb 100. The sprinkler bulb includes a sealed frangible housing 110; a circuit device 120 within the housing 110, wherein the circuit device 120 comprises an ultraviolet light source 125; and a photosensitive fluid 130 within the housing that in use undergoes a chemical reaction when exposed to ultraviolet light from the light source 125.

Claims

1. A sprinkler bulb for a fire suppression system, comprising: a sealed frangible housing (110); a circuit device (120) within the housing (110), wherein the circuit device (120) comprises an ultraviolet light source (125); and a photosensitive fluid (130) within the housing that in use undergoes a chemical reaction when exposed to ultraviolet light from the light source (125).

2. A sprinkler bulb as claimed in claim 1, wherein the circuit device (120) comprises a wireless module (160) for receiving power.

3. A sprinkler device as claimed in claim 1, wherein the circuit device (120) comprises a heating element operable to heat the photosensitive fluid (130).

4. A sprinkler bulb as claimed in claim 1, wherein the photosensitive fluid (130) is 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone.

5. A sprinkler bulb as claimed in claim 1, wherein the housing (110) is opaque to ultraviolet radiation.

6. A sprinkler bulb as claimed in claim 1, wherein the sprinkler bulb is arranged to break by using less than 1 Watts of power.

7. A sprinkler bulb as claimed in claim 1, wherein the sprinkler bulb is operable to break at a temperature of less than 57 Celsius.

8. A sprinkler bulb as claimed in claim 1, wherein the sealed frangible housing (110), the ultraviolet light source (125), and/or the photosensitive fluid (130) are configured such that the housing (110) will break when pressure within the housing (110) reaches a predetermined threshold.

9. A fire suppression system comprising a sprinkler device (200) and a sprinkler bulb (100) as claimed in claim 1.

10. A fire suppression system as claimed in claim 9, wherein the sprinkler device (200) is arranged to wirelessly provide power to the circuit device (120).

11. A method of activating a fire suppression system comprising a sprinkler bulb (100) comprising a sealed frangible housing (110) containing a photosensitive fluid (130), the method comprising: illuminating the photosensitive fluid (130) with ultraviolet light to cause it to undergo a chemical reaction and thereby break the housing (110).

12. A method as claimed in claim 11, comprising using less than 1 Watt of power to activate the sprinkler bulb (100).

13. A method as claimed in claim 11, comprising activating the sprinkler bulb (100) at a temperature of less than 57 Celsius.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Certain embodiments of the invention are described below by way of example only and with reference to the figures in which:

[0043] FIG. 1 shows a sprinkler bulb comprising a housing and a circuit device inside the housing, wherein the circuit device comprises an ultraviolet light source; and

[0044] FIG. 2 shows a schematic of the circuit device of FIG. 1.

DETAILED DESCRIPTION

[0045] FIG. 1 shows a sprinkler bulb 100 comprising a sealed frangible housing 110 and a circuit device 120 disposed within the housing 110. The circuit device 120 is therefore sealed inside the housing 110. The housing 110 also contains a photosensitive fluid 130 (in a liquid phase) and a gas bubble 140.

[0046] In use, the bulb 100 is located in a sprinkler device 200 (partially shown in FIG. 1) of a fire suppression system (not shown), and is positioned to hold a seal 210, plug or the like in place to prevent fire suppression fluid from leaving the sprinkler device 200. The seal 210 of the sprinkler device 200 is shown in FIG. 1. The sprinkler bulb 100 is arranged so that it prevents deployment of fire suppressant fluid from the sprinkler device 200 unless it breaks. In the event of a fire near the sprinkler device, the liquid 130 in the housing 110 will be heated and therefore pressure within the housing 110 will increase. Once the liquid 130 reaches a predetermined temperature (e.g. indicative of being near a fire), the resulting pressure from the heated liquid 130 will break the frangible housing 110 and the seal 210 of the sprinkler device 200 will no longer be held in place. Fire suppression fluid will then be discharged from the sprinkler device 200. The housing 110, liquid 130, and gas bubble 140 can be configured so that the housing 110 will break under predetermined conditions e.g. when the liquid 130 reaches a predetermined temperature, and hence when the housing 110 is exposed to a predetermined pressure thereby. The housing 110 may be formed of any suitable material such as glass, plastic, crystal, ceramic, quartzoid, or the like. Quartzoid may be preferred for its prevalence in the field.

[0047] The circuit device 120 is disposed within the housing 110. It is necessary for proper operation of the sprinkler bulb 100 that the housing 110 is sealed to prevent any and all leaks (e.g. to prevent ingress of any fluid into the housing 110, and/or prevent egress of any fluid out of the housing 110) otherwise the housing 110 may not break in the event of an emergency, as described above. The circuit device 120 is therefore sealed within the housing 110 and cannot simply be provided with external connections e.g. for power and/or communication. The sprinkler bulb 100 does not include any wires or solid electrical connections connected to the circuit device 120. As such, the housing 110 does not have any wires (e.g. a heating filament or an electrical connection) embedded therein.

[0048] The circuit device 120 is therefore provided with a wireless unit 160, for example an LC circuit, as shown in FIG. 2. The LC circuit comprises an inductor 164 and a capacitor 162, and is used to generate and/or receive signals at a predetermined frequency (e.g. the resonant frequency of the LC circuit) and/or amplitude. The circuit device 120 may therefore receive signals over a certain bandwidth from outside the housing 110 of the bulb 100. The circuit device 120 also comprises a power storage device 190, so it may receive and store power for its operation via the wireless unit 160 as needed, despite being sealed within the bulb housing 110. The circuit device 120 may also send and receive communication signals via the wireless unit 160, thereby being configured to communicate with other components of the sprinkler device 200 or of a fire suppression system outside the housing 110.

[0049] The circuit device 120 comprises a control unit 180 configured to control operation of the circuit device 120 and components thereof. The control unit 180 may control operation of the circuit device 120 autonomously, and/or may control operation of the circuit device 120 under the control of a remote system controller outside the housing 110 arranged to control e.g. a plurality of sprinkler devices and sprinkler bulbs. The control unit 180 may communicate with elements external to the bulb 100 via the wireless unit 160, and/or may be controlled by the remote system controller.

[0050] The circuit device 120 comprises a printed circuit board (PCB) and a plurality of electronic components. It comprises capacitors 300, one capacitor 162 forming part of the wireless unit 160, and one configured as a pressure sensor 150. The circuit device also comprises a temperature sensor 172 for sensing the temperature of the fluid 130 in the housing 110.

[0051] The circuit device 120 also comprises an ultraviolet (UV) light source 125, such as a UV bulb, a UV LED or the like. The UV light source 125 may be activated to emit UV radiation. Since the circuit device 120 is in, and surrounded by and exposed to, the photosensitive fluid 130, the fluid 130 will be exposed to UV radiation from the UV light source 125 when it is activated. The UV light source 125 is therefore arranged to illuminate the photosensitive fluid 130 when activated.

[0052] The photosensitive fluid 130 has a chemical structure that makes it sensitive to ultraviolet radiation. In use, ultraviolet radiation from the UV light source 125 causes the fluid 130 to undergo a chemical reaction, which subsequently causes pressure in the housing 110 to increase. The fluid 130 and the housing 110 may be selected and configured so that the pressure in the housing 110 will exceed a predetermined threshold needed to cause the housing 110 to break when the UV light source 125 is activated. The sprinkler bulb 100 may therefore be activated (i.e. the housing 110 broken for release of fire suppression fluid by the sprinkler device 200) by activating the UV light source 125. Thus, the sprinkler device 200 may be activated and fire suppression fluid may be dispensed.

[0053] Although any suitable light-activated substance may be used, the photosensitive fluid 130 is preferably 3M™ Novec™ 1230 Fire Protection Fluid, which is 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone. That is, the photosensitive fluid is CF3CF2C(═O)CF(CF3)2, or C2F5C(O)CF(CF3)2. The fluid 130 undergoes photolysis and substantial decay when exposed to UV radiation. It has a suitable UV cross-section with a maximum wavelength of absorbance at 306 nanometres (nm), and shows significant absorbance at wavelengths above 300 nm. The UV light source 125 is therefore configured to emit UV radiation above 300 nm, and is configured to emit radiation in the range of 300 nm to 320 nm, or 300 nm to 310 nm.

[0054] The photosensitive fluid 130 is also itself a fire suppression fluid, as well as being electrically non-conductive and safe for immersion of electronics (sometimes called ‘dry water’). The circuit device 120 can therefore be immersed in the fluid 130 without affecting its operability.

[0055] In use, the sprinkler bulb 100 may be commanded (e.g. by a remote system controller of a fire suppression system) to activate. The wireless unit 160 may receive an activation signal and the control unit 180 may activate the ultraviolet light source 125 in response to the activation signal. The ultraviolet light source 125 may then illuminate the photosensitive fluid 130 and cause it to undergo the chemical reaction, thereby increasing pressure within the housing 110 until the housing 110 breaks. Fire suppression fluid may be released from the sprinkler device 200 as a consequence of the housing 110 breaking. The fire suppression system may simultaneously command a plurality of sprinkler bulbs 100 to activate. The sprinkler bulbs 100 may be activated at temperatures lower than those required to activate them by heating.