GB2609006A

GB2609006A - Fire suppression system

Info

Publication number: GB2609006A
Application number: GB2110243.9A
Authority: GB
Inventors: Robert Thompson Neil; Samuels Gary; Mark Storey William
Original assignee: Bms Electrical Services Ltd
Current assignee: Bms Electrical Services Ltd
Priority date: 2021-07-16
Filing date: 2021-07-16
Publication date: 2023-01-25
Also published as: GB202110243D0

Abstract

A fire suppression system 10 for an electrical device 18 comprising a fluid sealable container 12, wherein at least a portion of the walls of the fluid sealable container are degradable walls. A pressure sensor 14 is configured to measure the internal pressure of the fluid sealable container and in response to a control unit 16 determining that the internal pressure of the fluid sealable container has reached a predetermined threshold of 500 kPa or less, the control unit activates a circuit breaker 22 to shut off the electricity supply to the electrical device. Preferably, in response to determining that the internal pressure has reached a second pre-determined threshold, the control unit activates an alarm.

Description

FIRE SUPPRESSION SYSTEM

The present invention relates to a fire suppression system, in particular, a fire suppression system for an electrical device. The invention further relates to a method of suppressing fire for an electrical device and the use of a fire suppression system for protecting an electrical device against fire or heat damage.

INTRODUCTION

Traditional automatic fire control and suppression systems typically include a plurality of individual sprinkler heads, which are usually ceiling mounted about the area to be protected. When actuated, the sprinkler heads release a spray of fire suppressing liquid, such as water, onto the area of the fire. Such systems may provide a degree of protection capability but often fail to prevent large-scale damage resulting from the fire. The use of water-based system may also cause secondary damage equal to or exceeding that caused by direct fire damage. In most cases, this results in an extended period of downtime and concomitant loss of revenue. A further problem with traditional fire suppression systems is that only limited insight is provided into how or where a fire started.

The use of water-based suppression systems for electrical facilities, which are a common cause of internal fires, is particularly undesirable. Automatic fire suppression systems that employ of a gaseous suppressant agent may allow a fire to be extinguished without damaging electronic equipment or machinery. These systems works by delivering a suppressant agent directly to the source of the heat, which extinguishes the fire. However, existing suppression systems of this type often offer only a single discharge solution. In particular, if an electrical source is still present, there is a real danger of re-ignition.

This invention aims to obviate or mitigate the existing disadvantages associated with automatic fire suppression systems noted above. Further objects of the invention will appear from the description which follows.

SUMMARY OF INVENTION

A first aspect of the invention provides a fire suppression system for an electrical device. The fire suppression system comprises a fluid sealable container, wherein at least a portion of the walls of the fluid sealable container are degradable walls. The fire suppression system also comprises a pressure sensor configured to monitor the internal pressure of the fluid sealable container. The fire suppression system further comprises a control unit, wherein the control unit is configured to communicate with the pressure sensor and a circuit breaker supplying the electrical device.

The control unit determines if the internal pressure of the fluid sealable container has reached a predetermined threshold, and in responsive to determining that the internal pressure has reached a pre-determined threshold, the control unit activates the circuit breaker to shut off the electricity supply to the electrical device.

Optionally, the degradable walls may be degradable when subject to abnormal heat; or subject to fire; or subject to both abnormal heat and fire. That is, when the fire suppression system of the present invention is in use, the walls of the fluid sealable container may degrade when the walls of the fluid sealable container are exposed to, or adjacent to, or when part of the walls are on fire. Additionally, or alternatively, the walls of the fluid sealable container may degrade or melt due to the presence of abnormal heat in the general area near to the fluid sealable container. The walls of the fluid sealable container may break due to an actual fire destroying the material of the walls of the fluid sealable container. In the context of the present invention, abnormal heat may include temperatures greater than or equal to 80 °C, or greater than or equal to 90 °C or greater than or equal to 100 °C or greater than or equal to C. In some embodiments the degradable walls, of the fluid sealable container, degrade when subject to temperatures greater than or equal to 80 °C; or greater than or equal to 90 °C; or greater than or equal to 100 °C; or greater than or equal to 110 °C.

In some embodiments, the fluid sealable container comprises a fire suppressant agent within the fluid sealable container.

In some embodiments the fluid sealable container is fluidly connected to a source of the fire suppressant agent. In particular embodiments, the source of the fire suppressant agent is a cylinder containing fire suppressant agent.

Advantageously, such fire suppression systems may provide dual protection against fire damage. In a first instance, the presence of a fire and/or abnormal heat source will cause the wall of fluid sealable container to degrade and rupture, thereby providing an outlet for the fire suppressant agent. In this way, primary mitigation is provided by the release of the fire suppressant agent at the location of the rupture and therefore at the source of the abnormal heat and/or fire. Secondary mitigation is achieved when the control system shuts off the electrical supply to the electrical device in response to the internal pressure of system reaching a pre-determined threshold caused by the rupture in the wall of the fluid sealable container and concomitant discharge of the fire suppressant fluid. Upon determining that the internal pressure has reached the pre-determined threshold, the control system activates the circuit breaker to shut off the electricity supply to the electrical device. Shutting off the electricity supply to the device in this way minimises the risk of further damage occurring as a result of a re-ignition event after the fire suppressant agent has been discharged.

As would be understood by a person skilled in the art, the pre-determined threshold value, or pre-determined minimum threshold, may be any pressure value indicative of a loss of pressure caused by a rupture in the degradable walls. The terms predetermined threshold and pre-determined minimum threshold may be used interchangeably herein. For example, the predetermined threshold may be 500 kPa.

Having a pre-determined threshold pressure value, before the circuit breaker is activated, may prevent false alarms of shutting off the electricity to an electric device when there is not a fire or abnormal heat.

In some embodiments the pre-determined threshold value is a sudden loss of pressure over time. In some embodiment the predetermined threshold is atmospheric pressure. In some embodiments the predetermined threshold is 150 kilopascals (kPa). In some embodiments the pre-determined threshold value is 102 kilopascals (kPa). Advantageously the control unit may determine if the signal is a false alarm or there is a pressure loss, potentially due to a fire.

In some embodiments the control unit can monitor the internal pressure of the fluid seal container over time and therefore can determine if the pressure loss is sudden or a gradual pressure loss. A sudden pressure loss may be indicative of a fire A gradual pressure loss may be indicative of a leak.

In some embodiments, the pressure sensor comprises more than one pressure sensor. Advantageously the control unit can compare pressure readings, or signals indicative of the internal pressure of the fluid sealed container, to determine if the loss in internal pressure of the fluid sealed container is likely to be due to a fire or not. Where the pressure sensor comprises more than one pressure sensor the pressure sensors may be the same type or different.

Optionally, the pressure sensor may comprise a pressure transducer.

Advantageously, a pressure transducer may allow for the continuous, or substantially continuous, monitoring of the internal pressure of the system.

The pressure sensor, may take readings at regular pre-set timings, for example every 10 minutes, or every 5 minutes, or every 2 minutes, or every one minute, or continuously, for example. These readings may be sent to the control unit.

In some embodiments, the pressure sensor may comprise a pneumatic pressure switch. Advantageously a pneumatic pressure switch is a simple device that may not make any signal to the control unit until a pre-set threshold is reached.

Optionally, the pneumatic pressure switch may be a dual pressure switch. Advantageously, a dual pressure switch provides digital output signals at two switch points, which may be independently tailored according to the operating pressure of the fire suppression system. For example, the dual pressure switch may be configured to produce a first signal output when the internal pressure of the system is less than or equal to a first pre-determined threshold and a second signal output when the internal pressure of the system is less than or equal to a second predetermined threshold. The first pre-determined threshold may be indicative of a loss of pressure due to a rupture in the degradable walls. A second pre-determined threshold may be indicative of a low pressure status. The terminology of "first" and "second" are used to aid understanding in the explanation that there is more than one pre-determined threshold, but not to limit the order, or possible values of the first and second pre-determined thresholds. The first and second pre-determined thresholds may be the same, the first pre-determined threshold may be greater than, or less than, the second pre-determined threshold.

Optionally, at least a portion of the walls of the fluid sealable container are flexible. Advantageously having flexible walls of the fluid sealable container may enable that the fluid contained in the fluid sealable container is stored at above atmospheric pressure. Flexible walls of the fluid sealable container may also allow easy positioning of the fluid sealable container. The wall or walls of the fluid sealable container may comprise a modified thermoplastic.

Optionally, the fluid sealable container may comprise a tube. Advantageously where the fluid sealable container is tube-shaped it may have a large surface area to volume ratio to offer more surface area exposed to potential fire risk hazards and electrical equipment. An elongated tube shape, of a fluid sealable container, may be placed within an electrical device.

Optionally, the fire suppressant agent may comprise a fluid. For example, the fire suppressant agent may be a gas at atmospheric pressure and stored as a pressurised liquid. This enables a larger volume of the fluid to be stored than what would be possible with the fluid sealable container alone. Having the fluid stored at a pressure above atmospheric pressure enables more fluid to be stored than if the fluid was only at atmospheric pressure. Advantageously, when the fire suppressant agent is stored at a pressure above atmospheric pressure, and when the walls of the fluid sealable container are ruptured, or degraded to such an extent that the wall of the fluid sealable container forms a hole, the fire suppressant agent should, due to the pressure being above atmospheric pressure, be rapidly discharged.

Optionally, the fire suppressant agent may be a halocarbon. For example, the fire suppressant agent may be a fluoroketone. Advantageously, such fire suppressant agents do not leave corrosive or abrasive residues following their use and can be safely employed to protect electrical and electronic equipment. Thus, secondary damage to the system or components as a result of the fire suppressant agent is minimised or prevented.

Advantageously the present invention can direct the fire suppressant agent to where it is needed most, therefore being effective at suppressing a fire but also causing less secondary damage elsewhere.

Optionally, the fire suppression system may further comprise a shunt trip device in communication with the control unit and the circuit breaker. Shunt trip devices are reliable devices to remotely trip a circuit breaker when a control voltage is applied.

The control unit, in response to determining that the internal pressure has reached the pre-determined threshold, activates the shunt trip device to shut off the electricity supply to the electrical device. Advantageously, once activated, a shunt trip device instantaneously triggers the circuit breaker ensuring a rapid disconnection of the electricity supply.

Alternatively, an undervoltage release (UVR) may be used to activate the circuit breaker instead of shunt trip device. In contrast to a shunt trip device, an undervoltage release trips the breaker when a control voltage is removed.

Optionally, the circuit breaker may be a moulded case circuit breaker (MCCB) or an air circuit breaker (ACB). Alternatively, the circuit breaker may comprise an in-line contactor.

Optionally, the control unit may further comprise a user-interface. This may enable easy use by a user. The user-interface may comprise a display screen.

Optionally, the fire suppression system may further comprise an alarm in communication with the control unit. In response to determining that the internal pressure has reached the pre-determined threshold, the control unit may activate the alarm. The alarm may comprise, for example, an audible alarm making a sound and/or a visual alarm, such as a light. In particular embodiments the visual alarm comprises a flashing light. In particular embodiments the alarm comprises both an audible alarm and a visual alarm.

Optionally, the control unit may be configured to interface with an external fire alarm system. This may enable the fire suppression system of the present invention to communicate with other fire alarm systems, able to warn a wider audience of a fire or fire risk, or of the shutting off of electricity to an electrical device, or activate further fire suppression equipment. In some embodiments the fire suppression system may interface with a mobile phone.

In some embodiments, the control unit comprises a microprocessor and a programmable logic controller (PLC). Advantageously this may enable the control unit to determine from the information received from the pressure sensor or pressure sensors if a fire is likely or not. Having a control unit that can process information from the pressure sensor or pressure sensors, means that the actual pressure sensors can be relatively cheap instruments where the control unit processes the information to avoid false alarms but accurately determine if the pressure change is due to a fire. The control unit can also process what to do with that information, for example, whether to shut off the electricity or sound an alarm, or in particular cases, such as outside of normal working hours, notify a user by other means, for example, by telephone.

Optionally, the fire suppression system may further comprise a housing configured to at least partially house the control unit. Advantageously, the housing of the fire suppression system may be tamperproof and help protect critical equipment within the control unit.

In some embodiments the fire suppression system further comprises an electrical connection to enable electricity supply for powering the fire suppression system. In some embodiments the fire suppression system comprises a battery configured to power the fire suppression system. Electrical powering of the fire suppression system is a cheap and easy method for powering the fire suppression system.

Advantageously a battery powered fire suppression system may be portable and able to be used away from conventional electrical power source.

A second aspect of the invention provides a method of suppressing fire, for example, in an electrical device, said method comprising the steps of: a) providing a fire suppression system of any embodiment as herein described; b) measuring, by the pressure sensor, the internal pressure of the system; c) generating, by the pressure sensor, a signal as a function of the internal pressure of the system; d) receiving, at the control unit, the signal generated by the pressure sensor system; e) determining, by the control unit, that the internal pressure has reached a pre-determined threshold; and f) activating, by the control unit in response to determining that the internal pressure has reached the pre-determined threshold, a circuit breaker to shut off the electricity supply to the electrical device.

The method of suppressing fire for an electrical device in some embodiments may further comprise the steps of: -determining, by the control unit, that the internal pressure has reached a second pre-determined threshold; and -activating an alarm, in response to the control unit determining from the second signal that the internal pressure of the fluid sealed container has reached a second pre-determined threshold.

In some embodiments, the method of suppressing fire further comprises the step of: placing the fluid sealable container adjacent to an electrical device.

In some embodiments, the method of suppressing fire further comprises the step of: placing the fluid sealable container at least partially around an electrical device.

In some embodiments, the method of suppressing fire further comprises the step of: placing the fluid sealable container at least partially within an electrical device.

A third aspect of the invention provides the use of a fire suppression system according to the first aspect for protecting an electrical device against fire or heat damage. The use of the fire suppression system may be a protective measure to safe guard against a fire should a fire or abnormal heat conditions happen. In this way, the use of the fire suppression system is merely stored in, or near to, an electrical device, or other potential fire hazards. Ideally the use of the fire suppression system would be stored close enough to the electrical device, or potential fire hazard, that should the walls of the fluid sealed container degrade the escaping fire suppressant agent will be close enough to suppress the fire.

In a typical use of the invention the fluid sealable container may be pumped with an inert gas, for example, Nitrogen, at a pressure above atmospheric pressure to detect any leaks in the fluid sealable container. Optionally the inert gas, for example, Nitrogen may be pumped into the fluid sealable container at a higher pressure than a pressure when in normal use set for fire detection, when detecting for leaks. Either way, in embodiments where an inert gas is used in this way, the inert gas, for example, Nitrogen, may be stored in the fluid sealable container at a pressure above atmospheric pressure when the fire suppression system is set. Various option of how the system is then used are possible.

It may be that the if there is a rupture or degradation of the walls of the fluid sealed container that this is detected as described herein and the control unit shuts off the electricity to the device and initiates whatever other notification(s) the control unit is programmed to do.

Additionally, in embodiments where the fluid sealable container is fluidly connected to a cylinder comprising a fire suppressing agent, a simple pressure valve may be set between the otherwise open contents of the cylinder and the fluid sealable container such that the pressure of the inert gas, for example, Nitrogen, keeps the pressure valve shut, until there is a reduction in pressure inside the fluid sealable container, then the pressure valve will open. Thus, in this embodiment if there is a rupture, or degradation of the walls of the fluid sealable container the gas inside the fluid sealable container will exit and then automatically the contents of the connected cylinder will be released and also exit the fluid sealable container at the point where the wall of the fluid sealable container were ruptured or degraded.

As the fire suppressant agent may be corrosive over time, having an inert gas inside the fluid sealable container when set for fire detection has the advantage that there is no internal corrosion or internal degrading of the walls of the fluid sealable container from the inert gas when the invention may be set for a long time to detect fire.

By the term "circuit breaker" as used herein this term is used to refer to a device that may be positioned and set to usually allow, in a normal usage, the flow of electricity to an electric device but can be activated or triggered to stop the flow of electricity.

By the term "degradable" as used herein, this term includes erosion, melting, rupture and any form of breaking that the fluid seal of the wall, for example, is broken and fluid may pass through the wall.

By the term "external fire alarm system" as used herein, this term includes a mobile phone or a building's fire alarm system, or a fire-station or fire monitoring computer or control room.

By the term "fluid sealable container" as used herein, this term refers to a container that is sealable to substantially prevent fluid escaping from within the container.

By the term "interface" and "interfacing" as used herein, these terms includes any interaction between two systems, for example, two electrical system that the two electrical system can exchange signals or information. Also includes interactions between a system and a user, for example.

By the term "pressure sensor" as used herein this refers to a device that can read, monitor or detect a pressure, typically of a fluid. The term as used herein includes devices that also comprise a means to display or communicate pressure readings; or communicate or send a signal to indicate the detected pressure, whether this is a pre-set threshold value of a pressure or otherwise.

By the term "pressure switch" as used herein, this term is used to describe a device that when a pre-determined pressure threshold is detected the device can switch something either off or on, and, optionally, send a signal indicative that the pre-determined threshold has been detected.

By the term "shutting off electricity" as used herein, this term also includes preventing the supply of electricity and can be used to, among other things; 1) stop electricity being supplied, but also 2) where currently there is no electricity currently being supplied this term includes where further supply of electricity will be stopped or shut off, or prevented. At least until further steps or actions.

By the term "suppressed" as used herein, this term does not need to be complete in suppression that the fire will be extinguished but includes any degree or amount of suppressing, or reducing, or hindering, or preventing expansion of a fire.

By the term "suppressing fire" as used herein also includes potentially suppressing a fire, for example, in that the device is placed near a potential fire hazard that should a fire start, in the future, the fire will be suppressed, thus the term includes both present time and future.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings illustrate presently exemplary embodiments of the disclosure, and together with the general description given above and the detailed description of the embodiments given below, serve to explain, by way of example, the principles of the disclosure Figure 1 shows a schematic diagram illustrating a fire suppression system according to the invention; Figure 2 shows a control unit of a fire suppression system according to the invention; and Figure 3 shows a user interface of a fire suppression system according to the invention.

DETAILED DESCRIPTION

The present invention provides a fire suppression system comprising a primary mitigation factor that delivers a fire suppressant agent to the source of the fire. and a second mitigation factor that prevents further damage by shutting off the electricity supply to a device being protected. Thus, fire suppression systems of the invention may be particularly suited to protect an electrical device, for example, a switchboard, a distribution board, an electronic panel, or mechanical equipment.

Figure 1 illustrates, in schematic form, an example of a fire suppression system 10 according to the invention. System 10 includes a fluid sealable container 12, a pressure sensor 14, and a control unit 16.

At least a portion of the walls of the fluid sealable container 12 are degradable walls.

For example, in the illustrated embodiment, the fluid sealable container 12 comprises a network of fire detection tubing. The fire detection tubing comprises degradable walls, which degrade when subject to abnormal heat, such as at temperatures above 110 C. Fire degradable wall containers are known in the art, one such example is sold under the brand FIRETRACEO. The actual material of the walls can be altered to degrade at different temperatures, thus a degradable wall can be chosen to degrade at a particular desired temperature.

The network of fire detection tubing may be installed such that all the electrical connections on an electrical device 18 are within the protection of the tubing above and below the point at which an arc or abnormal temperature event may occur. For the purposes of clarity, only a single electrical device 18 is shown in the illustrated embodiment but it should be understood that the following description is applicable to a plurality of electrical devices.

The fire detection tubing is fluidly connected to a source of a fire suppressant agent.

The fire suppressant agent may be stored under pressure, for example at a pressure above atmospheric pressure, in a vessel, such as a cylinder 20. For example, the fire suppressant agent may be stored at a pressure of 700 kPa (7 Bar). The cylinder, for example, may be fitted adjacent to the electrical device 18 that it is protecting, as shown in Figure 1. Examples of suitable fire suppressant agents include synthetic compounds, such as a halocarbon. In one embodiment, the fire suppressant agent is dodecafluoro-2-methylpentan-3-one, which is sold under the tradename Novec® 1230. Novec® 1230 has relatively low toxicity and leaves no residue so is safe for equipment, including sensitive electronics and machinery. Other suitable fire suppressant agents are known in the art.

After the tubing has been installed, the system 10 is initially charged with Nitrogen gas to a pre-determined internal pressure to check for leaks. In one example, the fire detection tubing may be charged with Nitrogen to an internal pressure of approximately 1200 kPa (12 Bar). In addition to allowing for a leak-test of the system, the presence of Nitrogen gas in the fire detection tubing provides the additional advantage of reducing or preventing long-term exposure of the fire detection tubing to the fire suppressant agent. Once the system has been tested and found to be gas fight, a cylinder valve (not shown) located behind the pressure sensor on the cylinder 20 is manually opened to ready the system for use.

In use, the pressurised tubing wall will degrade and rupture in the event of an abnormal heat source, such as a fire event or arc. This rupture in the tubing wall provides an outlet for the Nitrogen gas and the fire suppressant agent will discharge from the cylinder 20. As a result, the fire suppressant agent is released at the location of the rupture and onto the source of the abnormal temperature and/or fire condition. In this way, the fire suppressant agent rapidly fills the hazard area and extinguishes the source of heat. All electronics are kept dry and there are no toxic agents or chemicals involved. Thus, after release there is no residue and collateral damage to associated devices is avoided.

A rupture of the fire detection tubing and concomitant release of the fire suppressant agent, will also result in a rapid decrease in the internal pressure of the system. The pressure sensor, which may be coupled to the head of the cylinder 20 as shown in Figure 1, is used to measure the internal pressure of the fire suppression system 10.

For example, the pressure sensor 14 may be configured to measure the internal pressure of the cylinder 20 when the internal volume of the cylinder 20 is in fluid communication with the internal volume of the fluid sealable container 12.

The pressure sensor 14 also comprises a signal system for sending a signal as a function of the internal pressure to the control unit 16. For example, in the illustrated embodiment, the pressure sensor 14 is a pressure transducer. A pressure transducer, also called a pressure transmitter, is a sensor that converts pressure into an analogue electrical signal. The analogue signal generated by the pressure transducer is proportional to the detected internal pressure of the system.

In one example, the pressure transducer generates a current output in the range 4 to 20 mA, which corresponds to 0 to 100% of the operating range of transducer. Thus, for a pressure transducer having an operating range up to 1200 kPa, the output signal range 4 to 20 mA equates to 0 to 1200 kPa. The pressure transducer is interfaced with the control unit 16, which is equipped with a microprocessor and a programmable logic controller (PLC). The PLC receives the analogue signal from the pressure transducer via an analogue input module and coverts it to a digital output through an analogue-to-digital converter (ND converter). Specifically, the current value is read by the analogue module on the PLC and converted it to a digital output in the range 0 to 27648. The PLC can then use the digital output to monitor the internal pressure of the system. In this way, the interfacing of the pressure transducer with the control unit 16 allows for the continuous monitoring of the internal pressure of the system in a close to real-time manner. The PLC is further configured to compare the internal pressure of the system with a pre-determined threshold, wherein the pre-determined threshold is a pressure value indicative of a rupture in the fire detection tubing. In particular, the PLC may be configured to determine that a threshold pressure has been reached using variable set-points in number format based on the digital output described above. For example, a set-point of 6912 equates to a signal of 8mA, which corresponds to a pressure value equivalent to 25% of the operating range of the pressure transducer and a set-point of 13824 equates to a signal of 12mA, which corresponds to a pressure value equivalent to 50% of the operating range of the pressure transducer. Thus, a plurality of pre-determined threshold values may be set and adjusted by a user by configuring the set-point values using the control unit 16. The detection of a particular threshold value can then be processed within the PLC logic to carry out actions relative to the system requirements, as described in more detail below.

In one example, the pre-determined internal pressure may be equal to or less than 500 kPa (5 Bar). In operation, the rupture of the fire detection tubing and concomitant release of the fire suppressant agent causes a decrease in the internal pressure of the system. This decrease in internal pressure is detected by the pressure transducer and communicated to the control unit 16 via the analogue output signal as detailed above. The PLC is configured to activate a digital output when the pre-determined internal pressure is reached that is capable of shunting a circuit breaker 22, which is supplying the electrical device, thereby causing it to shut down. For example, upon detecting that the pre-determined internal pressure has been reached, the PLC may transmit a digital signal to a activate a shunt trip 24, which in turn activates the circuit breaker 22 ensuring a rapid disconnection from the mains supply and isolation of the source of ignition. Automatically isolating the power in this way minimises the risk of any potential secondary rise in heat source, which may occur once the fire suppressant agent is fully consumed after discharge. This ensures that any damage and potential future damage is kept to a minimum. In an alternative embodiment, the shunt trip 24 may be replaced with an under-voltage release (UVR) device. The PLC of the control unit 16 may be configured to simultaneously activate an audible and/or visual alarm 26 when it is determined that a loss of pressure has occurred.

In another example, the PLC of the control unit 16 may be configured to compare the internal pressure of the system to more than one pre-determined threshold. For example, when the control unit 16 determines that the internal pressure of the system is less than or equal to a first pre-determined threshold, the control unit 16 may activate a low pressure alarm. When the control unit 16 determines that the internal pressure of the system is less than or equal to a second pre-determined threshold, which is lower than the first pre-determined threshold and indicative of a loss of pressure due to a rupture in the degradable walls, the control unit 16 may activate the circuit breaker 22 which is supplying the electrical device in the manner described above. For example, the first pre-determined threshold may be less than or equal to approximately 700 kPa (7 Bar) and the second pre-determined threshold may be less than or equal to approximately 500 kPa (5 Bar).

In an alternative example, an pneumatic dual pressure switch may be used. The dual pressure switch may be programmed to output a first pressure signal when the first pre-determined pressure is reached and output a second signal when the second pre-determined pressure is reached. Upon receiving the first output signal, the control unit 16 activates a low pressure alarm and upon receiving the second output signal the control unit 16 activates the circuit breaker 22 to shut off the electricity supply, as described above.

The control unit 16 may further comprise a user-interface 28, as shown in Figures 2 and 3, including a display panel 30 and touchscreen functionality. As shown in Figure 3, the user-interface 28 may allow a user to perform system overrides, system resets, or routine keystrokes, such as the press of a mute button or the acknowledgement of pop-up warnings. Advantageously, the first pre-determined threshold or, where appropriate, the first and second pre-determined threshold may be set and adjusted using the control unit, for example, via the user-interface 28.

Additionally, the display panel 30 may also display visual representations of system parameters and setting, as well as providing a real-time health status of the entire system. The control unit 16 may further store and display events such as low-pressure warnings, service warning and agent release events. In this way, the control unit 16 and may provide a user with a visual indication, via the display panel 30, of the internal pressure of the system and a discharge log. The internal pressure of the system may be displayed as an absolute value or as a percentage of the maximum operating pressure. Such information may also be viewed retrospectively via the display panel in the event of an agent release to determine what actions were taken before and after an agent release. The control unit 16 may also be password protected via the user-interface to prevent unauthorised personnel switching the power back on until all repairs / checks have been carried out! tested.

Where multiple systems 10 are fitted in a premises, the control unit 16 can be configured to communicate with each system 10 to provide a single control point covering a complete site installation. Therefore, the control unit 16 may monitor each individual systems and provide a real time discharge notification/alarm warning via the user-interface. The system 10 may also be in communication with an external fire alarm system via the PLC and user-interface. As well as shunting the supplying circuit breaker, the PLC will also send an electrical signal to the external fire alarm system in the event of a fire even to activate the external fire alarm system.

The control unit 16 may also be configured to communicate with a remote terminal, such as a smart phone 32 or similar. In some embodiments, the remote terminal may use additional software, e.g., an app or other application, which replicates the main display panel. For example, the PLC may transmit a digital output signal to a local SMS relay 34 to allows an operator to remotely monitor the systems and/or perform functions, such as system re-starts, as shown in Figure 1.

In some embodiments, a Fail-Safe PLC may be used such that, in the event of a system error, loss of electrical supply or component failure, the PLC can be pre-programmed to bring the system 10 to a safe state upon shutdown, meaning that the electrical device is not left unprotected. Additionally, the control unit 16 may include an auxiliary power source, such as a 24vdc battery, to ensure that all circuits remain energised in the event of a mains supply failure.

Fire suppression systems according to the invention are well suited to the fire protection cross a broad range of user applications. Systems according to the invention are especially effective and efficient in an internal space housing electrical equipment such as a switchboard, a distribution board, or an electronic panel.

It will be appreciated by persons skilled in the art that the above embodiment has been described by way of example only and not in any!imitative sense, and that various alterations and modifications are possible without departing from the scope of the invention as defined by the appended claims.

Claims

CLAIMS1. A fire suppression system for an electrical device comprising a fluid sealable container, wherein at least a portion of the walls of the fluid sealable container are degradable walls; a pressure sensor configured to measure the internal pressure of the fluid sealable container; and, a control unit, wherein the control unit is configured to communicate with the pressure sensor and a circuit breaker supplying the electrical device, and wherein the control unit determines if the internal pressure of the fluid sealable container has reached a predetermined threshold, and in response to determining that the internal pressure has reached a pre-determined threshold, the control unit activates the circuit breaker to shut off the electricity supply to the electrical device.
2. The fire suppression system according to claim 1, wherein the pressure sensor comprises a pressure transducer.
3. The fire suppression system according to any one of claims 1 or 2, wherein the pressure sensor comprises a pneumatic dual-pressure switch.
4. The fire suppression system according to any of claims 1 to 3, wherein the degradable walls are degradable when subject to abnormal heat; or subject to fire; or subject to both abnormal heat and fire.
5. The fire suppression system according to any preceding claim, wherein at least a portion of the walls of the fluid sealable container are flexible.
6. The fire suppression system according to any preceding claim, wherein the fluid sealable container comprises a tube.
7. The fire suppression system according to any preceding claim, wherein the fluid sealable container comprises a fire suppressant agent within the fluid sealable container.
8. The fire suppression system according to any preceding claim, wherein the fluid sealable container is fluidly connected to a source of the fire suppressant agent.
9. The fire suppression system according to claim 7 or 8, wherein the fire suppressant agent comprises a fluid.
10. The fire suppression system according to claims 7 to 9, wherein the fire suppressant agent is a halocarbon, optionally, a fluoroketone.
11. The fire suppression system according to any preceding claim, wherein the predetermined threshold is less than or equal to 500 kPa.
12. The fire suppression system according to any preceding claim, further comprising a shunt trip device in communication with the control unit and the circuit breaker, wherein the control unit, in response to determining that the internal pressure has reached the pre-determined threshold, activates the shunt trip to shut off the electricity supply to the electrical device.
13. The fire suppression system according to any preceding claim, further comprising an undervoltage release in communication with the control unit and the circuit breaker, wherein the control unit, in response to determining that the internal pressure has reached the pre-determined threshold, activates the undervoltage release to shut off the electricity supply to the electrical device.
14. The fire suppression system according to any preceding claim, wherein the circuit breaker is a moulded case circuit breaker (MCCB) or an air circuit breaker (ACB).
15. The fire suppression system according to any one of claim 1 to 13, wherein the circuit breaker comprises in-line contactor.
16. The fire suppression system according to any previous claim, wherein the control unit further comprises a user-interface.
17. The fire suppression system according to any previous claim, wherein the system is configured to interface with an external fire alarm system.
18. The fire suppression system according to any previous claim, wherein the fire suppression system further comprises a housing configured to, at least partially house the control unit.
19. The fire suppression system according to any previous claim wherein the control unit, in response to determining that the internal pressure has reached a second pre-determined threshold, activates an alarm.
20. A method of suppressing fire for an electrical device, said method comprising the steps of: a) providing a fire suppression system of any of claims 1 to 19; b) measuring, by the pressure sensor, the internal pressure of the fluid sealable container; and c) generating, the pressure sensor, a signal as a function of the internal pressure of the fluid sealable container; d) receiving, at a control unit, the signal from the pressure sensor; e) determining, by the control unit, that the internal pressure has reached a pre-determined threshold; and e) activating, in response to the control unit determining that the internal pressure has reached the pre-determined threshold, a circuit breaker to shut off the electricity supply to the electrical device.
21. A method of suppressing fire for an electrical device as claimed in claim 20, further comprising the step of: -determining, by the control unit, that the internal pressure has reached a second pre-determined threshold -activating an alarm, in response to the control unit determining that the internal pressure of the fluid sealed container has reached the second predetermined threshold.
22. A method of suppressing fire for an electrical device as claimed in claims 20 or 21, wherein the pressure sensor comprises a pneumatic dual pressure switch or a pressure transducer.
23. The use of a fire suppression system according to any of claims 1 to 19 for protecting an electrical device against fire or heat damage.