WO2016146759A1

WO2016146759A1 - Cylinder damage response system

Info

Publication number: WO2016146759A1
Application number: PCT/EP2016/055829
Authority: WO
Inventors: Christopher John COWLES; Derrick Ernest Hilton; Christine KANDZIORA; Colin HADEN
Original assignee: Linde Aktiengesellschaft
Priority date: 2015-03-17
Filing date: 2016-03-17
Publication date: 2016-09-22
Also published as: GB201504456D0

Abstract

A safety monitoring system for a cylinder for containing compressible fluid. The system comprises a sensor assembly for measuring and/or detecting a cylinder status, and output sensor data which indicates the cylinder status. A processor is configured to receive the sensor data and perform a hazard analysis comprising determining whether the cylinder status satisfies a hazard condition. In response to the determination being positive, an electronic signal is sent to an electronic assembly for use in effecting a hazard response action.

Description

CYLINDER DAMAGE RESPONSE SYSTEM

FIELD OF THE INVENTION

The present invention relates to a system for effecting a response to damage experienced by, or likely to be experienced by, a cylinder containing a compressible fluid. In particular, the invention relates to a system for safety monitoring of the cylinder, configured to measure a cylinder status to perform a hazard analysis and, based on that analysis, output an electronic signal to an electronic assembly to effect a hazard response action.

BACKGROUND OF THE INVENTION

The use of containers, typically cylinders, for storing and dispensing

pressurised fluid is ubiquitous. Some notable examples include their use to store and dispense gases for medical purposes, for scientific research or for industrial applications. The cylinders may further be used to transport pressurised fluid between locations, either to be transferred to local storage for later use or to be extracted on demand from the cylinder at the point of use.

Although reference is made to a "cylinder", it will be understood that the invention is applicable broadly to all portable pressurised gas containers whether they are strictly in the form of a cylinder or not.

Such cylinders are used to supply gas for a range of applications including welding and cutting hoses and torches, gas packaging machines and laboratory equipment.

It is expected that such cylinders will experience wear and tear throughout their operational life as a result of transport and use. Wear and tear can, for example, result from exposure to changing environmental conditions (such as variations in temperature), or undergoing physical stress such as small shock impacts from being stacked, or loaded and unloaded from a pallet. Cylinders are designed to withstand a certain degree of normal wear and tear and still operate within operational parameters.

However, during its operational life, a cylinder can experience conditions that exceed normal conditions that the cylinder is designed to withstand. One example would be if the cylinder is dropped from a height, or if the cylinder topples, it can experience a shock that might damage the cylinder. A second example is the exposure of part of the cylinder to an extreme temperature, such as being burned by a blowtorch. These 'extremes' in conditions might result in damage to the container that could comprise the ability of that cylinder to maintain the compressible fluid at a target pressure, or, in a worst-case-scenario, result in a compromise in cylinder integrity that could result in injury or death.

When a cylinder is suspected to have been exposed to such extreme conditions, it is withdrawn from service and put through a more thorough inspection or investigation procedure to ascertain the extent of any damage. However, this is costly both in terms and time and money, but also means that the cylinder is out of service for a longer period of time. In addition, the cylinders will spend the majority of the time outside of the distributor's influence and control. It is therefore not always possible to identify when a cylinder has been exposed to extreme conditions, as a visual inspection is not always sufficient such as in the example of the exposure to an intense heat from a blow torch. Giving all cylinders a thorough inspection is not practical in terms of time and money, and it is also not practical to expect end users of the cylinders to provide the distributor with full and accurate usage information.

There is a need, therefore, to mitigate any damage experienced by a cylinder to prevent catastrophic failure of that cylinder during use, for example by making it easier for the cylinder distributor to be made aware of any extreme conditions to which the cylinder has been exposed, such that a thorough inspection may be carried out if deemed necessary.

The present invention seeks to address this problem by providing a system for safety monitoring of a cylinder status which provides various advantages over those of the prior art.

SUMMARY OF THE INVENTION

There is provided a system and method for safety monitoring as set out in the appended claims.

According to a first aspect of the present invention, there is provided a system for safety monitoring of a cylinder for containing compressible fluid, the system comprising a sensor assembly configured to measure and/or detect a cylinder status and output sensor data indicating the cylinder status; and a processing means configured to: receive the sensor data and perform a hazard analysis, the hazard analysis comprising determining whether the cylinder status satisfies a hazard condition; and in response to the determination being positive, outputting an electronic signal to an electronic assembly for use in effecting a hazard response action. This system has advantages over the state of the art in that the cylinder status can be monitored electronically, and results in the output of an electronic signal for use in a variety of apparatus to inform a user or supplier of a hazard, correct a hazard or prevent a hazard.

Advantageously, the hazard condition is based on at least one of: properties of the cylinder, properties of the compressible fluid, properties of a valve assembly attached to the cylinder, and the environment external to the cylinder. Thus the hazard condition is a condition explicitly linked to properties of a cylinder or items associated with the cylinder, as opposed to being generic hazard conditions. This can provide that the safety monitoring can more accurately recognise potential hazards specific to the cylinder in question.

Further advantageously, the hazard condition is a first hazard condition of a plurality of hazard conditions, and the processing means is further configured such that the hazard analysis comprises determining whether the cylinder status satisfies a second hazard condition of the plurality of hazard conditions. A cylinder can be parameterised by a many things, including temperature, pressure, structural integrity and the like, which can lead to many potential hazards occurring should a

combination of these parameters change such that the cylinder becomes unsafe. By including multiple hazard conditions within the hazard analysis, the system can be tailored to provide a response action to a variety of situations.

Advantageously, the electronic assembly comprises a plurality of electronic components and the processing means is further configured to select, based on said hazard analysis, an electronic component from the plurality of electronic components for output of the electronic signal. For example, different electronic components may be more suitable for hazard response actions than others and the system is configured to ensure that the most suitable apparatus is chosen, thereby increasing the effectiveness of a hazard response action. Further advantageously, each electronic component is associated with a respective hazard condition of the plurality of hazard conditions, and the processing means is configured to select an electronic component for output of the electronic signal upon a determination that the cylinder status satisfies the hazard condition associated with that electronic component.

Advantageously, the sensor assembly comprises a plurality of sensors configured to measure and/or detect a respective plurality of cylinder properties, such that the sensor data indicating the cylinder status comprises sensor data indicating each of the plurality of cylinder properties. The more information that can be gathered from a cylinder, the most effective the safety monitoring of that cylinder.

Advantageously, the hazard condition is associated with a first cylinder property of the plurality of cylinder properties, wherein the hazard analysis comprises determining whether the first cylinder property satisfies the associated hazard condition, wherein the hazard condition is a function of at least one other cylinder property of the plurality of cylinder properties. Some cylinder properties may be interrelated, and while a measured value for a first cylinder property may by itself not necessarily indicate a hazard, when a second cylinder property is observed at a certain value, the first cylinder property does indicate a hazard.

Further advantageously, the hazard condition is a first hazard condition of a plurality of hazard conditions, each of the plurality of hazard conditions associated with a respective one of the plurality of cylinder properties, wherein the processing means is further configured such that the hazard analysis comprises determining whether each measured cylinder property satisfies the hazard condition associated with that cylinder property. Thus, within the safety monitoring system, hazard conditions can be specifically associated with certain cylinder properties.

In one embodiment, the sensor assembly comprises a shock sensor configured to measure and/or detect a shock experienced by the cylinder. Thus, any potential damage experienced by the cylinder can be monitored, which can provide a warning to the user, allow for identification of issues before they arise and prevent accumulation of long-term damage.

In another embodiment, the sensor assembly comprises a vibration sensor configured to measure and/or a vibration experienced by the cylinder, comprising a measurement and/or detection of at least one of a vibration frequency and a vibration amplitude.

In another embodiment, the sensor assembly comprises a sensor configured to measure and/or detect an orientation of an axis of the cylinder relative to a reference axis. A cylinder can be put at risk if oriented at an angle that puts it at risk of falling over. Advantageously, the hazard condition is satisfied if the orientation of the axis of the cylinder is measured and/or detected to be outside a predetermined value range of angles relative to the reference axis. One example is that the predetermined value range of angles comprises all angles below a threshold angle relative to the predetermined reference axis. When a cylinder topples, this can not only damage the cylinder but be a health and safety hazard, and the safety monitoring in this system facilitates a hazard response action that can provide a warning to the user of the cylinder to prevent such an occurrence.

In another embodiment, the sensor assembly comprises at least one temperature sensor configured to measure and/or detect a temperature of the cylinder. Extremes in temperature can be very dangerous, as heat can affect the metallurgical structure of the cylinder, thereby compromising cylinder safety. This may be particularly dangerous when the cylinder is used to store flammable products. The sensor data that includes a cylinder temperature can be used in a hazard analysis to warn a user of an over temperature condition, or can be used to effect an action to reduce a hazard risk (e.g. shutting a cylinder valve to prevent further release of flammable fluid into an environment with an increasing

temperature). Advantageously, the sensor assembly comprises a plurality of temperature sensors located at different physical locations with respect to the cylinder configured to measure and/or detect a plurality of cylinder temperatures. Thus, the sensor assembly can be configured to measure temperatures at different points on its body - for example, one may be fixed internal to the cylinder, one external, or several along its body.

Advantageously, the sensor assembly further comprises a pressure sensor configured to measure and/or detect a pressure of the compressible fluid of the cylinder. While the pressure of the compressible fluid is not a physical attribute of the cylinder, it can be considered part of a cylinder status as it may impact the operation of a cylinder, and can supplement hazard analysis in respect of other cylinder properties. For example, a cylinder full of compressible gas is more at risk of an explosion in a high temperature than a cylinder that is empty.

Advantageously, the step of determining whether the cylinder status satisfies a hazard condition comprises determining whether a measured value of the cylinder status is a value outside a predetermined value range associated with the cylinder status. Specifically, this embodiment implements a hazard analysis by specifying a range of values that are deemed safe, and determining whether a measured value of a cylinder property lies within that range or not. This is a reliable way to explicitly specify what is and is not sufficient for a hazard condition to be satisfied.

In one embodiment, the electronic assembly comprises at least one of the following electronic components: an alarm configured to receive the electronic signal and, as the hazard response action, provide an audible warning in response; a display configured to receive the electronic signal and, as the hazard response action, provide a visual warning in response; a communication device configured to receive the electronic signal and, as the hazard response action, to report the indication of the cylinder status and the result of the hazard analysis; and a shut-off valve for the cylinder, wherein the electronic signal and, as the hazard response action, is provided to the shut-off valve to close the shut-off valve to prevent release of compressible fluid from the cylinder. Each electronic component can perform a particular type of hazard response action, and allows for a flexible solution to a hazard occurring.

In one embodiment, the system further comprises a data storage means, configured to receive the electronic signal and store the sensor data and the result of the hazard analysis. This allows for historic data to be stored, allowing for customisation of hazard conditions and also for subsequent analysis by the cylinder distributor to assess cylinder status and usage statistics.

Advantageously, the system further comprises a cylinder and the system is integrated into the cylinder. Integrating the system and the cylinder as a single unit means that operation of the system can be simplified, being specific to the cylinder to which it is attached.

In one embodiment, the sensor assembly is configured to perform a failsafe analysis, the failsafe analysis comprising determining whether the cylinder status satisfies a failsafe condition, wherein the sensor assembly is configured to output a failsafe electronic signal to the electronic assembly in response to the failsafe determination being positive. In this embodiment, a safety net is provided for use with the cylinder. For example, should the processing means not be operating correctly, the sensor assembly provides an emergency reaction to prevent extremely dangerous situations. Also advantageously, this failsafe can be implemented instead of providing information to a processing means, when a simple reaction is all that is necessary. This would safe processing power on the processing means that could otherwise be used for other tasks.

Other preferred features of the present invention are set out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings in which:

Figure 1 is a schematic drawing of a system for safety monitoring in accordance with the present invention.

Figure 2 illustrates an exemplary hazard analysis process.

Figure 3 is an illustration of different cylinder statuses complying with a range criterion of a hazard condition.

Figure 4 illustrates an exemplary process of a safety monitoring system employing multiple hazard conditions.

Figure 5 illustrates a shock hazard analysis process.

Figure 6 illustrates an orientation of a cylinder which is measured and/or detected as part of an orientation hazard analysis process.

Figure 7 illustrates an orientation hazard analysis process.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Embodiments of the present invention are now provided with reference to the accompanying figures.

Figure 1 illustrates a system 1 for safety monitoring of a cylinder 2 for containing compressible fluid 4. The system 1 comprises a sensor assembly 6 configured to measure and/or detect a cylinder status and output sensor data 10 indicating the cylinder status. As will be explained in more detail below, the sensor assembly 6 may comprise sensors 7 suitable to measure and/or detect a cylinder status by measuring and/or detecting the following cylinder properties: pressure of the compressible fluid 4, temperature, a cylinder tilt angle, a shock experienced by the cylinder 2 and vibration experienced by the cylinder 2. However, these are understood to be exemplary only, and it would be understood that the sensor assembly 6 may include any sensor suitable for measuring and/or detecting a property of the cylinder 2 that indicates or describes a cylinder status. The sensor assembly 6 may be configured to provide constant measurement/detection of the cylinder status, be configured to periodically measure/detect the cylinder status and/or be configured to measure/detect a cylinder status upon response to a stimulus (such as turning on of the valve 3).

The system further comprises a processing means 14, which is understood to be any suitable means for processing and generating information electronically, such as a processor in a computer. The processing means 14 is configured to receive the sensor data 10 and perform a hazard analysis 1 6. The sensor data 10 is provided in a format that can be processed by the processing means 14 to yield the cylinder status, and any data relevant to that cylinder status. For example, the sensor assembly 6 can produce sensor data 10 that includes an indicator of a particular cylinder status (such as 'positive' or 'negative' indicator) that can then be interpreted by the processing means 14. Alternatively, or additionally, the sensor assembly 6 can produce sensor data 10 that indicates a measured value 12 of the cylinder status, such as a particular temperature measured by a temperature sensor.

Advantageously, the sensor assembly 6 and/or the processing means 14 may be integrated into a valve 3 that is attached to the cylinder 2, forming an electronic valve assembly. This can reduce complexity of set up for the user, as by simply attaching the electronic valve assembly to the cylinder, a system 1 for safety monitoring can be provided without the need to separately configure and attach each sensor to the cylinder 2. However, providing the sensor assembly 6 in addition to the valve 3 (or in addition to an electronic valve assembly with some sensors integrated) may have its own advantages. Specifically, in such a system, sensors may be provided at different points on the cylinder 2, thereby collecting a more complete dataset for subsequent hazard analysis.

The hazard analysis 1 6 comprises determining whether the cylinder status satisfies a hazard condition 13. For example, the processing means 14 can run an algorithm or computer code to analyse the sensor data 10 received to determine whether the cylinder status complies with certain criteria (such as a determination of whether a shock experienced by the cylinder 2 is of an intensity above a value likely to cause damage). In the embodiments of the invention described herein, when a hazard condition 1 6 is satisfied, it is an indication of at least one of the following: the cylinder 2 has experienced a hazardous situation, the cylinder 2 is currently a hazard risk, and/or the cylinder 2 will be in a hazardous situation in the future. A 'hazardous situation' is taken to include the experiencing of damage to or abuse of the cylinder 2. The processing means 14 is further configured to, in response to the

determination being positive, output an electronic signal 20 to an electronic assembly 22 for use in effecting a hazard response action. Hazard response actions are understood to mean an action taken in response to the recognition that hazard conditions have occurred, are occurring, or are likely to occur in future. Hazard response actions can be dependent on the nature of the hazard as identified by the hazard analysis (e.g. indicating a pre-emptive warning on a device, or shutting of the valve). Different embodiments related to hazard response actions will be explained in more detail below.

Optionally, the hazard condition may be provided from another component connected to the processing means 14, such as a data storage device 15, or alternatively from a user input 17. This allows the cylinder distributor to provide predefined hazard conditions and associated criteria, or to customise the criteria prior to distribution of the cylinder 2 (e.g. if the cylinder 2 has suffered some shock damage but is still serviceable, then the threshold for a shock experienced by a cylinder 2 to satisfy a hazard condition may be lowered). This allows for flexibility in providing the safety monitoring, by means of adjusting what the hazard analysis 1 6 will determine to satisfy a hazard condition. Additionally, the processing means 14 may be configured to adjust the hazard condition based on additional information provided in the data storage device 15 or user input 17. For example, a cylinder 2 can have a stored plurality of hazard conditions and associated criteria for a cylinder 2, where each of the plurality of hazard conditions is associated with a type of compressible fluid 4. A user or manufacturer will provide the type of compressible fluid (e.g. Nitrogen), allowing the processing means 14 to select or adjust the hazard condition and associated criteria based on this information for use in a hazard analysis 1 6.

Advantageously, the hazard condition is based on at least one of: properties of the cylinder 2, properties of the compressible fluid 4, properties of a valve assembly attached to the cylinder 2, and the environment external to the cylinder. Different cylinder models may have different operating parameters and therefore different safety thresholds. For example, cylinders may be made from different alloys, meaning that they can be heated to different temperatures before a hazard is likely to occur. Another example is cylinders with wider bases can be tilted to a larger angle before toppling and consequently a different criterion related to cylinder angle displacement must be complied with in order to satisfy the hazard condition and a hazard response action effected. Furthermore, sometimes the type of compressible fluid 4 inside the cylinder 2 may affect the ranges in which cylinder properties can operate; for example a gaseous material such as Entonox (being a mixture of nitrous oxide and oxygen) is required to be stored between specific temperature limits to avoid damage to this material, and to ensure that this material performs to the required level. Additionally, the environment external to the cylinder 2 can be indicative of a hazard. For example, the temperature of the cylinder 2 itself may be within an acceptable range at a specific moment in time, but the external

environment of the cylinder may be at a hazardously high temperature, which would eventually result in the cylinder heating up to a hazardous temperature. Thus, basing the hazard condition on the environment external to the cylinder can be advantageous in a more effective safety monitoring of the cylinder.

As stated above, the hazard analysis 1 6 comprises determining whether the cylinder status satisfies a hazard condition. Figure 2 illustrates the methodology employed in conducting the hazard analysis 1 6. At step 100, an indication of a cylinder status is provided (which may be extracted, computed or derived from sensor data 10). At block 102 it is determined whether the cylinder status satisfies a hazard condition. There may be multiple ways in which the processing means 14 can determine that the hazard condition is satisfied. In the illustrated embodiments, the hazard condition comprises one or more criteria (illustrated as criterion A and criterion B in Figure 2), and the processing means 14 being configured to determine whether the hazard condition is satisfied comprises the processing means 14 being configured to determine whether each of the criteria are complied with. This is illustrated in Figure 2, where the hazard condition process block 102 includes blocks 104, with each block being a determination whether the cylinder status complies with a criterion of the hazard condition. As illustrated in Figure 2, when both criterion A and criterion B are complied with, the hazard condition 13 is satisfied. When either criterion A or criterion B are not satisfied, the hazard condition is not satisfied. This exemplary only, and it is understood that it may only be necessary for some of the criteria to be satisfied, and that the number or type of criteria that must be satisfied will depend on the specific hazard condition. For example, one criterion to be satisfied would be whether a measured value of the cylinder status lies within a predetermined value range associated with a particular cylinder property indicated by the cylinder status (described in more detail below). This would include examples such as whether a measured temperature exceeds a threshold, or whether a measured pressure drops below a threshold. Another exemplary criterion is the criterion of whether a valve 3 of the cylinder 2 is currently closed. The hazard condition may be considered satisfied by the meeting of a single criterion, or if a combination of criteria are satisfied - for example, if the pressure drops below a certain value and the valve is closed, potentially indicating a leak. Each criterion may be independently assessed as part of the determination of whether the cylinder status satisfies the hazard condition.

In response to a positive determination at block 102 (i.e. that the hazard condition is satisfied), a hazard response action is effected/provided, as illustrated at block 106. In the present invention, this is by means of an electronic signal 20 being output to an electronic assembly 22 for use in a hazard response action. In response to a negative determination at block 102 (i.e. that the hazard condition is not satisfied), no action is taken, as illustrated at block 108.

Figure 3 illustrates an example of a hazard analysis conducted by the processing means 14, wherein determining whether the cylinder status satisfies a hazard condition comprises determining whether a measured value 12 of the cylinder status is a value outside a predetermined value range 18 associated with the cylinder status. Thus, in this example, the hazard condition comprises a range criterion, being a criterion that a value for the cylinder status must be outside a specified range of values. If this range criterion is complied with, then the hazard condition is satisfied. For the purposes of illustration, within Figure 3 the cylinder status is a temperature of the cylinder 2, but it is nevertheless understood other cylinder properties may equally apply to describe the cylinder status. In Figure 3, a range 30 of values for the cylinder status is provided, where the measured value 12 for the cylinder status is a value on this range 30. Within Figure 3, the predetermined value range 18 is the range of values between a lower bounding bar 32a and an upper bounding bar 32b on the range 30. In a process in accordance with this exemplary embodiment, the processing means 14 receives the sensor data 10, where that sensor data 10 indicates a first measured value 34a within the range 20. As illustrated in Figure 3, the first measured value 34a falls within the predetermined value range 18 between the lower bounding bar 32a and the upper bounding bar 32b. Thus, the determination of whether the measured value 34a falls outside the predetermined value range 18 would be negative. This means that the range criterion would not be complied with, resulting in the hazard condition not being satisfied and an electronic signal 20 not being outputted by the processing means 14. A contrary example is also illustrated in Figure 3, where the sensor data 10 indicates a second measured value 34b. This second measured value 34b lies outside the predetermined value range 18, meaning that the

determination of whether the measured value 34b falls outside the predetermined value range would be positive. Thus, the range criterion would be complied with, resulting in the hazard condition being satisfied and an electronic signal 20 being output by the processing means 14. Providing a range criterion as part of the hazard condition is advantageous for hazards that might potentially occur at two extremes of a value range, such as a cylinder temperature, where extreme heat and extreme cold can be equally damaging to the cylinder 2.

It is to be understood that range criteria may be defined differently, by means of the predetermined value range 18 being defined in a different manner. In particular, the hazard condition may comprise a threshold criterion, being a more specific form of range criterion. For a threshold criterion, instead of being a range of values between two specific points, the predetermined value range 18 may be all values below a threshold value. This threshold criterion example is additionally illustrated in Figure 3, by the alternative predetermined value range 18b, which is defined as all values of the cylinder status below a threshold value, in this case lower bounding bar 32a. In this example, the hazard analysis would yield a positive determination for the first measured value 34a, but a negative determination for the second measured value 34b. This type of predetermined range may be more appropriate for cylinder properties like shock experienced by the cylinder 2 - all values below a threshold are considered 'safe', and all above the threshold are considered 'dangerous'.

For avoidance of doubt, the above described hazard analysis process is exemplary, and other criteria can be applied alternatively, or in addition to, the comparison of a measured value to a predetermined range. In some embodiments, the hazard condition has only one criterion associated with it (such as a range criterion), and it is sufficient that a cylinder status comply with that sole criterion for the hazard condition to be satisfied.

The embodiments described above are with respect to determination whether a single hazard condition has been satisfied. Advantageously, the processing means 14 is configured to perform a hazard analysis 1 6 of a cylinder status with respect to multiple hazard conditions. Specifically, in this advantageous

embodiment, the hazard condition is a first hazard condition of a plurality of hazard conditions, and the processing means 14 is further configured such that the hazard analysis 1 6 comprises determining whether the cylinder status satisfies a second hazard condition of the plurality of hazard conditions. By providing different hazard conditions within the hazard analysis, the system can be configured identify different hazards and thus to provide different hazard response actions in respect of the cylinder status measured and/or detected by the sensor assembly 6. For example, if one hazard condition is satisfied by a cylinder status, this can be indicative of a different hazard to the hazard indicated by another hazard condition being satisfied by the cylinder status. For example, a high cylinder temperature could satisfy a hazard condition associated with risk of reduced structural integrity of the cylinder 2, or it could also satisfy a hazard condition associated with elevated cylinder pressure. Alternatively, satisfying different hazard conditions may be indicative of a different severity of the same hazard (e.g. increasing risk of reduced structural integrity). Each hazard condition may comprise a respective number of criteria associated with that hazard condition, and thus different hazard conditions may be defined by the respective criteria associated with the hazard conditions. Furthermore, each of the plurality of hazard conditions may be interrelated. Optionally, each hazard condition may comprise a criterion that one or more of the hazard conditions is or is not satisfied. For example, the first hazard condition may include the criterion that the second hazard condition is not satisfied. This would mean that a hazard response action initiated in respect of the first hazard condition being satisfied would cease as soon as the second hazard condition is satisfied. For instance, a display may be providing a warning that a low-risk hazard is occurring, but as soon as a high risk hazard condition is satisfied, the system will cease displaying the low-risk warning in favour of the high risk warning.

Advantageously, when a processing means 14 is configured to carry out a hazard analysis using a plurality of hazard conditions, the system 1 is configured to effect different hazard response actions based on that hazard analysis 1 6. In one exemplary embodiment, the electronic assembly 22 comprises a plurality of electronic components and the processing means 14 is further configured to select, based on said hazard analysis 1 6, an electronic component from the plurality of electronic components for output of the electronic signal 20. For example, the plurality of electronic components may include an alarm 23, a display 24 and a wireless communication device 25, as illustrated in Figure 1 . While not explicitly illustrated as such in Figure 1 , the valve 3 may also be considered an electronic component in the plurality of electronic components of the electronic assembly 22. Each electronic component may be configured to perform a different hazard response action, such as the alarm 23 for producing an audible warning, and the display 24 for producing a visual warning. The result of the hazard analysis 1 6 may indicate that different severities of hazard are identified, warranting an action from different electronic components.

One manner in which the above may be achieved is in the advantageous embodiment where each electronic component is associated with a respective hazard condition of the plurality of hazard conditions, and the processing means 14 is configured to select an electronic component for output of the electronic signal 20 upon a determination that the cylinder status satisfies the hazard condition associated with that electronic component. For example, there may be a first hazard condition associated with the display 24, a second hazard condition associated with the alarm 23 and a third hazard condition associated with the valve 3. Thus, if the processing means 14 determines that the first hazard condition is satisfied, the display 24 is selected and the electronic signal 20 is provided to the display 24 to display warning. If the processing means 14 determines that the second hazard condition is satisfied, then the alarm 23 is selected and the electronic signal 20 is provided to the alarm 23 to provide an audible warning. If the processing means 14 determines that the third hazard condition is satisfied, then the valve 3 is selected and the electronic signal 20 is provided to the valve 3 to shut off the valve. The system may be configured that if two or more hazard conditions are satisfied, then all the electronic components associated with those hazard conditions are selected. Alternatively, in the embodiment where the hazard condition includes a criterion that one or more other hazard conditions are satisfied, a reduced number of electronic devices may be selected when two or more hazard conditions are satisfied, thus reducing power consumed by electronic components.

Alternatively or additionally, more than one hazard condition may be

associated with an electronic component. Thus, a determination of each of the one or more hazard criteria being satisfied will result in the selection of the same electronic component, but a different electronic signal 20 will be generated and provided to that component to produce a variation on the hazard response action effected by that electronic component. For example, a first hazard condition and a second hazard condition are both associated with the display 24, and the first hazard condition is satisfied when the temperature reaches a first value, and the second hazard condition is satisfied when the temperature reaches a second value. Thus, in this example, when the first hazard condition is satisfied a first warning is generated by the display 24 (e.g. "WARNING: Unsafe temperature detected", and if the second hazard condition is satisfied, a second warning is instead generated by the display 24 (e.g. "WARNING: TEMPERATURE AT DANGEROUS LEVEL - EVACUATE ROOM").

Further alternatively or additionally, one hazard condition may be associated with two electronic components, resulting in the selection of each associated electronic component when the hazard condition is satisfied. For example, the outputting of an electronic signal 20 to both an alarm and a display for both an audible warning and a visual warning.

The above described embodiments are provided with respect of the status of the cylinder 2 being described by a single cylinder property (e.g. temperature) being measured by the sensor assembly 6, and a hazard analysis being performed based on that property. However, it is to be understood that multiple properties of a cylinder 2 can be measured and used to perform a hazard analysis 1 6. Many of these properties can be interrelated, and simultaneous measurement and analysis of a plurality of properties can provide a more effective hazard analysis 1 6. For example, it is well-known pressure and temperature of a gas are co-dependent; if a cylinder 2 is determined to be at a very high pressure, then this will affect whether a temperature is deemed to be unsafe, such as from the risk of the cylinder 2 exploding from increased gas pressure. Additionally, simultaneous measurement of cylinder properties can provide information to the cylinder distributor for purposes of analysis. For example, if a cylinder angle is measured together with a cylinder shock, if it has been determined that an intense shock has been measured co- incidentally with a sharp change in angle, this would indicate that the cylinder 2 has fallen over, but if an intense shock has been measured without a change in angle then this indicates that the cylinder 2 has been dropped on its end - this would make subsequent inspection and analysis easier for maintenance of the cylinders.

Such advantageous embodiments are described below, wherein the sensor assembly 6 comprises a plurality of sensors 7 configured to measure and/or detect a respective plurality of cylinder properties, such that the sensor data 10 indicating the cylinder status comprises sensor data 10 indicating each of the plurality of cylinder properties. Thus, a cylinder 'status' can not only be described by a single type of sensor measurement, (as described above with respect to Figure 3), but also by a plurality of sensor measurements describing the overall state of the cylinder 2.

Advantageously, the sensor assembly 6 comprises at least one temperature sensor configured to measure and/or detect a temperature of the cylinder 2. Further advantageously, the sensor assembly 6 further comprises a pressure sensor configured to measure and/or detect a pressure of the compressible fluid 4 of the cylinder 2. Other sensors within the plurality of sensors 7 may include a shock sensor, a vibration sensor, a cylinder angle detection sensor and a sensor to whether the valve 3 is open, shut or in an intermediate state.

The safety monitoring of a system using information yielded from a plurality of sensors is illustrated in Figure 4. The sensor assembly 6 is configured to provide sensor data 10 that indicates a cylinder status 8 that comprises an indication of each of the plurality of cylinder properties (for example, a cylinder temperature 8a, a pressure 8b of the compressible fluid 4 and a cylinder orientation 8c). This sensor data 10 is provided to the processing means 14 to perform a hazard analysis 1 6 using the plurality of cylinder properties. Each hazard condition identifies a specific hazard for the cylinder 2, and these may not be specifically associated with each cylinder property. Rather, any number of cylinder properties can be used to determine whether this hazard condition is complied with. An example is illustrated in Figure 4, where a general determination 50 is made whether a cylinder status satisfies a hazard condition, where the cylinder status includes an indication of all the cylinder properties. The hazard condition may comprise one or more criteria for use in determining whether the hazard condition is satisfied, as described above, where the hazard condition includes at least one criteria associated with each cylinder property (e.g. for the hazard condition to be satisfied, the cylinder temperature 8a must comply with a temperature range criterion, the pressure 8b must comply with a pressure range criterion and the orientation angle 8c must comply with an orientation range criterion).

The processing means 14 may perform a hazard analysis 1 6 using multiple cylinder properties in other ways. In an advantageous embodiment, the hazard condition is associated with a first cylinder property of the plurality of cylinder properties, and the other cylinder properties are used as parameters in the hazard analysis 1 6. Specifically, in this embodiment, the hazard analysis comprises a determining whether the first cylinder property satisfies the associated hazard condition, wherein the hazard condition is a function of at least one other cylinder property of the plurality of cylinder properties. This means that whether the first cylinder property satisfies the hazard condition will be dependent on at least one other cylinder property. This is also illustrated in Figure 4, where the determination 52 is made whether the cylinder temperature 8a satisfies the hazard condition, where the cylinder pressure 8b is also provided for use in the determining step such that the hazard condition is based on the pressure of the compressible fluid 4. This may be implemented, by the hazard condition comprising a criterion (such a range criterion) that will change based on the at least one other cylinder property, meaning that whether a certain cylinder property complies with this criterion will depend on other cylinder properties. An example is illustrated in Figure 4, where the hazard condition being used by the processing means 14 for the cylinder temperature 8a comprises a range criterion such that the hazard condition is satisfied upon a determination 54 that the range criterion is complied with (e.g. when the temperature exceeds a threshold value, where the threshold value may be a value above which the cylinder 2 is at risk of exploding from compromised structural integrity).

However, if the cylinder 2 is being used to contain a compressible fluid 4 at a high pressure (e.g. it has just been filled), a lower temperature may still put the cylinder 2 at the same risk, and the hazard condition would not be sufficient to warn of a hazard. In this embodiment, the range criterion is dependent on the pressure 8b, such that the threshold temperature will be a function of the pressure 8b of the compressible fluid 4 measured by the sensor assembly 6. This is illustrated in Figure 4 by the pressure 8b being provided to the determination step 54. In this embodiment, the dependence of the hazard condition on the at least one other cylinder property can be specified. For example, a range criterion can have multiple ranges programmed, where the range used for the hazard analysis will depend on the at least one other cylinder properties (e.g. if the cylinder pressure is between 1 kPa and 2kPa, then the range criterion uses a first predetermined temperature value range, but if the pressure is between 2kPa and 3kPa, then the range criterion uses a second predetermined temperature value range). This flexibility allows for customised hazard conditions that can be tailored for specific cylinder assemblies. However, such bespoke specification can be time consuming and may require additional memory. An advantageous alternative would be to specify a functional relationship that can be calculated in situ by the processing means 14 (e.g. the temperature threshold of a threshold criterion is dependent on a measured pressure via the ideal gas equation).

Advantageously, the hazard condition is a first hazard condition of a plurality of hazard conditions, each of the plurality of hazard conditions associated with a respective one of the plurality of cylinder properties. Thus, a hazard analysis 1 6 described above with respect to one cylinder property can be performed, in parallel, for each cylinder property. Specifically, the processing means 14 is further configured such that the hazard analysis comprises determining whether each measured cylinder property satisfies the hazard condition associated with that cylinder property. This is illustrated in Figure 4, where the safety monitoring system makes a first determination 52 whether the temperature 8a satisfies a first hazard condition (with optional dependence of criteria on other cylinder properties as described above), a second determination 54 whether a pressure 8b satisfies a second hazard condition, and a third determination 56 whether an orientation angle satisfies a third hazard condition. In an exemplary process, a value for temperature is measured and it is determined whether this value lies outside a predetermined range of temperature values, while simultaneously a value for pressure is measured and it is determined if that pressure value lies outside a predetermined range of pressures, and an electronic signal 20 is generated in response to either or both of the determinations being positive. The hazard analysis 1 6 may be performed such that a determination of whether each cylinder property satisfies a respective hazard condition is made separately and independently. This implementation may be used when two cylinder properties may not have a co-dependence (e.g. cylinder angle and temperature). Alternatively, this embodiment may be additionally configured as described above, such that a hazard condition is dependent on whether one or more other hazard conditions are satisfied. Thus within this hazard analysis, each cylinder property can be provided to determine whether it satisfies a hazard condition in combination with being used as a parameter for a separate determination of whether another cylinder property satisfies another hazard condition. The functional relationship between hazard conditions can be provided in a bespoke manner by a user or manufacturer, in a manner similar to how each criterion of the hazard condition can be programmed or modified based on user requirements (as described above).

As described above, in response to a positive determination that the cylinder status satisfies a hazard condition, the processing means 14 is configured to output an electronic signal 20 to an electronic assembly 22 for use in effecting a hazard response action.

Advantageously, the electronic assembly 22 comprises at least one of several electronic components, and optionally the system 1 may include the electronic assembly 20. Such an electronic component may be an alarm configured to receive the electronic signal 20 and, as the hazard response action, provide an audible warning in response. Different types of audible warnings can be provided, including, but not limited to, a pre-recorded voice instruction, a periodic beep or a siren. The type and formatting of the audible alarm can be calculated by the processing means 14 based on information stored in the data storage device 15 or input at a user input device 17. The type and formatting of the audible alarm can also depend on which hazard condition has been satisfied by the cylinder status.

Another electronic component of the electronic assembly 20 can be a display 24 configured to receive the electronic signal 20 and, as the hazard response action, provide a visual warning in response. Different types of visual warning can be provided, which can be based at least in part on the display being used. For example, text, symbols or the turning on of a light are examples of visual warnings. The type and formatting of the visual warning can be calculated by the processing means 14 based on information stored in a data storage device or input at a user device. The type and formatting of the visual warning can also depend on which hazard condition has been satisfied by the cylinder status.

Another electronic component of the electronic assembly 20 can be a communication device 25 configured to receive the electronic signal 20 and, as the hazard response action, to report the indication of the cylinder status and the result of the hazard analysis 1 6. The communication device may be, for example, a wireless transponder, an RFID tag or a Bluetooth device. The purpose of this component is to allow for reporting of the status of a cylinder 2, and may be used both by the cylinder user (e.g. on a laptop) or another party, such as the cylinder distributor for use in long-term monitoring of the cylinder 2. For example, in response to significant damage experience by the cylinder 2, the cylinder distributor may be able to dispatch an employee to pick up the cylinder 2.

Another electronic component of the electronic assembly 20 can be a shut-off valve 3 for the cylinder 2 configured to receive the electronic signal 20 and, as the hazard response action, close the shut-off valve 3 to prevent release of compressible fluid 4 from the cylinder 2. Such a hazard response action is particularly useful when continued release of compressible fluid 4 from the cylinder 2 poses a health and safety risk. For example, if the cylinder 2 is providing combustible gas to a blowtorch for welding, a spike in temperature being detected on a region of the cylinder body could indicate that the blowtorch is accidentally directed to the cylinder 2. Thus, the processing means 14 will provide an electronic signal 20 to the shut-off valve to prevent the release of gas, thereby cutting off the blowtorch and pre-empting a rupture of the cylinder 2. However, turning off the valve 3 when it is not desired can cause unnecessary interruption of a task requiring the use of the compressible fluid (e.g. scientific experiments, welding). This could be only a minor frustration or annoyance, but it has the potential to comprise or scuttle the task being performed. Thus, it is advantageous to shut off the valve 3 as a hazard response action only once another hazard response action has already been performed, such as a warning that the valve will soon be shut off. In this advantageous embodiment, the electronic signal 20 is provided to the valve 3 to shut off the valve in response to a hazard condition being satisfied, where that hazard condition comprises a warning criterion, where the warning criterion is complied with if at least one other hazard condition has been satisfied.

The type and nature of the hazard response action effected by each electronic component will depend on the contents of the electronic signal 20 provided to the electronic assembly 22. The contents of the electronic signal 20 can be generated by the processing means 14 depending on which hazard condition is satisfied, and also which criteria of the hazard condition is satisfied. Thus, different electronic signals may be provided to the same electronic component to provide different hazard response actions implemented by that electronic component.

Advantageously, the system 1 further comprises a data storage means 19, configured to receive the electronic signal 20 and store the sensor data 10 and the result of the hazard analysis 1 6. This stored data can be retrieved at a later date to provide a historic record of hazard analyses. The stored data may also be used to modify a hazard condition used by the processing means 14. This can provide some degree of feedback on the safety monitoring of the cylinder 2.

The above described systems are adapted to be used on a cylinder 2, providing flexibility for multiple configurations. However, in and advantageous embodiment, the system 1 further comprises the cylinder 2 and is integrated into the cylinder 2.

The system 1 is set up to provide an automated and robust safety monitoring, through the processing of data by the processing means 14. However, it is possible that certain extreme conditions exist that do not require a hazard analysis 1 6 and indicate, prima facie, a safety risk. It is desirable to provide a failsafe in addition to the hazard analysis to ensure that a suitable response is taken irrespective of any hazard conditions that may be configured. In this advantageous embodiment, the sensor assembly 6 is configured to perform a failsafe analysis, the failsafe analysis comprising determining whether the cylinder status satisfies a failsafe condition, wherein the sensor assembly 6 is configured to output a failsafe electronic signal to the electronic assembly 22 in response to the failsafe determination being positive. For example, some shock sensors are not configured to measure a shock, but are configured to output a signal when a shock above a threshold has been received (for example, a magnetic ball in holder will be displaced by a large enough force). The displacement of the ball from the holder is an example of a failsafe condition being satisfied, and does not require data processing by the processing means 14. In this sense, a 'dead man's switch' can be applied where if the ball is displaced from the holder, a break in a circuit is detected resulting in a shut-off of the valve.

An exemplary embodiment of safety monitoring is illustrated in Figure 5 and described below. In this embodiment, the system is configured to perform a shock hazard analysis, and the sensor assembly 6 comprises a shock sensor configured to measure and/or detect a shock experienced by the cylinder 2. A shock is a sudden acceleration caused by an impact, such as that experienced by the cylinder 2 when the cylinder 2 falls over, is dropped or hit. High intensity shocks can cause significant damage to a cylinder 2 by rupturing or otherwise breaking the cylinder 2, or compromising the integrity of the cylinder 2 to a point where a breakage will occur imminently, putting the user at risk. Lower intensity shocks may not have the same risk associated, but repeated exposure to such low intensity shocks can degrade the cylinder 2 over time. In either case, it is preferable to provide a hazard response action to the user of the cylinder 2 and/or the cylinder distributor for the purposes of identifying a present safety hazard as well as improving long-term cylinder

maintenance. Different types of shock sensors can be used to measure and/or detect a shock such as an accelerometer, or a magnetic ball lodged in a holder, displaceable by a shock.

The hazard shock analysis can be performed by determining whether an indication of a cylinder status satisfies one or more shock hazard conditions. The one or more hazard shock conditions includes a primary shock hazard condition 202, where the cylinder status satisfies the primary shock hazard condition 202 if the cylinder 2 has experienced a shock at all (i.e. if the sensor data 10 indicates that a shock has been detected). If the cylinder status does not satisfy the primary shock hazard condition 202, then no action is taken, as illustrated at block 203. The one or more shock hazard conditions includes a second shock hazard condition 204, the second shock hazard condition 204 comprising a threshold criterion, where the cylinder status complies with the shock threshold criterion if the experienced shock is above a threshold value. If the shock threshold criterion is not complied with, then no action is taken, again illustrated at block 203. If the shock threshold criterion is complied with, then the second shock hazard condition 204 is satisfied, resulting in a hazard response action. The hazard response actions illustrated in Figure 5 include locking the cylinder valve at block 206, displaying a warning at block 208, or communicating a signal to the cylinder distributor at block 210 (which will then enable the distributor to dispatch a truck to pick up the package). The system 1 can be configured to implement any or all of these hazard response actions in response to the second shock hazard condition 204 being satisfied.

Another cylinder property that can be used within a hazard analysis can be a vibration experienced by the cylinder 2. This vibration may be a vibration that propagates through the cylinder following an impact or shock, or may be due to the cylinder being in physical contact with another vibrating entity (e.g. an operational power supply, vacuum pump or the like). A vibration experienced by a cylinder can be a hazard - for example, a vibration can dislodge electrical components, or loosen screwthread connections of cylinder or valve components. Thus, in an

advantageous embodiment, the system is configured to perform a vibration hazard analysis. In this embodiment, the sensor assembly 6 comprises a vibration sensor configured to measure and/or detect a vibration experienced by the cylinder 2, comprising a measurement and/or detection of at least one of a vibration frequency and a vibration amplitude. The vibration experienced by the cylinder 2 can be used in a vibration hazard analysis to determine if the vibration experienced by the cylinder 2 satisfies a vibration hazard condition. Advantageously, the sensor assembly 6 comprises a plurality of vibration sensors at different physical locations on the cylinder 2. This provides more complete information regarding vibrations at different points across the cylinder 2. Alternatively, there may be a single vibration sensor provided at one location on the cylinder (e.g. on the valve 3, or on the base of the cylinder 2), and the processing means 14 uses the single measurement to

predict/calculate the vibration occurring at other points on the cylinder 2, such as through an algorithm or other computer code (e.g. using a predefined model of the propagation of vibration through the cylinder 2 and/or valve 3).

For the vibration hazard analysis, the same methodology can be applied as described above with respect to Figure 5. In particular, there may exist more than one vibration hazard condition, including a first, primary vibration hazard condition, which is satisfied if the cylinder 2 experiences a vibration at all, and a second vibration hazard condition, which may be specified by a threshold criteria which is complied with if the vibration amplitude is above a threshold value. Furthermore, the same response actions can be taken upon determination that the vibration satisfies the vibration hazard condition as are illustrated in Figure 5.

When considering vibration hazards, the frequency of vibration can be crucial, such as in the circumstance where a low-amplitude vibration at one frequency can be more dangerous than a higher amplitude vibration at a different frequency. For example, the vibration may be occurring at the resonant frequency of the cylinder or a component attached to the cylinder.

In one example, vibration at the resonant frequency of the valve can lead to its connection to the cylinder loosening and thus indicate an imminent safety concern.

In another example, vibration at the resonant of an electronic component within the valve may loosen the component, which may not be a safety concern in the short term, but would indicate maintenance should be provided.

If left unchecked, this vibration can amplify to a level that could be considered hazardous. Thus, in one advantageous embodiment, the vibration hazard analysis comprises determining whether the vibration cylinder property satisfies a vibration hazard condition that comprises a frequency criterion, where the frequency criterion must be complied with for the vibration hazard condition to be satisfied. The frequency criterion is complied with if the frequency of the vibration matches a predetermined frequency or is a harmonic (an integer multiple) of that frequency. The frequency criterion may also be satisfied if the frequency falls within a range centred on the predetermined frequency (or a harmonic thereof).

The vibration hazard analysis may comprise a plurality of vibration hazard conditions to provide an effective response to detection of a hazardous frequency (e.g. a resonant frequency). For example, each of the plurality of vibration hazard conditions comprises a frequency criterion as described above together with an amplitude range criterion (where a vibration amplitude complies with the amplitude range criterion if that amplitude falls outside a predetermined range, or above/below a threshold). Each vibration hazard condition has the same frequency criterion, but different amplitude criterions. Thus, as the amplitude of vibration increases, different hazard conditions are satisfied and thus different hazard response actions can be provided by the electronic assembly. Namely, if a resonant frequency is detected but the amplitude is low, a warning message is provided for the user to take action. If the amplitude grows, then another hazard condition is then satisfied and an alarm starts to sound indicating, for example, that cylinder components are in danger of becoming detached or unscrewed from the vibration.

Cylinders are in general designed to be used in an upright position. Due to their size and weight, should the cylinder 2 fall an injury to a user of the cylinder 2 can result. Furthermore, a cylinder 2 can be damaged by the fall, as a result from the shock experienced by hitting the ground. One embodiment of safety monitoring is a system arranged to provide a warning should a cylinder 2 be placed in a state that puts it at risk of falling over. In this embodiment the sensor assembly 6 comprises an axis sensor configured to measure and/or detect an orientation of an axis 318 of the cylinder 2 relative to a reference axis 320, as illustrated in Figure 6. The axis 318 is an axis running the length of the cylinder 2, and the reference axis 320 is a null vertical axis, being the same as the axis 318 of the cylinder 2 when the cylinder 2 is placed on a flat surface. The orientation of the axis 318 relative to the reference axis 320 is described by the angle 322, and the axis sensor is configured to measure the orientation of the axis 318 by measuring said angle 322. Also illustrated in Figure 6 is a hazardous angle 324, being the angle at which the cylinder 2 is on the verge of toppling - i.e. the angle of a cylinder orientation such that the force from the weight of the cylinder 2 acts through a point on the edge of the cylinder base. This is a hazardous angle because when the orientation angle 322 exceeds this angle, the cylinder 2 will fall over. Thus, it is preferable to provide a warning to the user when the orientation angle approaches this hazardous angle, allowing the user to correct the orientation of the cylinder 2.

An exemplary embodiment of safety monitoring of the orientation of the cylinder 2 is described in Figure 7, where the system performs an orientation hazard analysis. The orientation hazard analysis comprises an orientation hazard condition 302, which is satisfied if the orientation of the axis 318 of the cylinder 2 is measured or detected to be outside a predetermined value range of angles relative to the reference axis 320. For example, the predetermined value range of angles comprises all angles below a threshold angle relative to the reference axis. In this example, the angle 322 complies with the range criterion when the angle 322 exceeds a particular value, such as a value within a few degrees of the hazardous angle 324. The exact value can be varied, and based on physical parameters such as the cylinder dimensions or qualitative parameters (e.g. limiting the warning to a limited range to avoid being warned too frequently). Whether the orientation hazard condition 302 specifies a range of values above a threshold or below a threshold will depend on how the angles are defined. It is understood that the system can be configured accordingly to utilise a preferential axis reference frame.

When the orientation hazard condition 302 is not satisfied, no action is taken and the orientation sensor continues to operate and the process returns to block 302. Thus the cylinder angle is being continually monitored by the system 1 to determine whether the orientation hazard condition 302 is satisfied.

When the hazard condition is satisfied a hazard response action results to alert the user. For example, a warning can be displayed, as illustrated by block 306, and/or an alarm can be sounded, as illustrated at block 304. Further hazard response actions as described above can be implemented in response to the orientation hazard condition 302 being satisfied. The warning and alarm will continue to sound until a user undertakes an action, such as at block 308. This may be to adjust the angle of the cylinder 2 in view of making a correction. The process then passes back to block 302, and if the action taken by the user is sufficient to rectify the angle, then the orientation hazard condition 302 is no longer satisfied and the alarm and warning will not continue to sound. Alternatively, the user may simply cancel the alarm through an input to the user input 17. Unless an appropriate action is taken, the hazard condition will continue to be satisfied and the alarm and warning displayed. The above described orientation hazard condition 302 is described in reference to a range criterion of the hazard condition, but it is understood other criteria can be included that must be complied with in order for the orientation hazard condition 302 to be satisfied. Embodiments have been described above where the sensor assembly 6 comprises at least one temperature sensor configured to measure and/or detect a temperature of the cylinder 2. A hazard analysis 1 6 is then conducted to determine whether the temperature satisfies a hazard condition, which may comprise criteria such as a range criterion. In a further advantageous embodiment, the sensor assembly 6 comprises a plurality of temperature sensors located at different physical locations with respect to the cylinder 2, and configured to measure and/or detect a plurality of cylinder temperatures. By providing multiple temperature sensors, multiple sensor readings can be provided, thereby providing redundancy on a hazard analysis. For example, a hazard analysis 1 6 may comprise a hazard condition that is only satisfied if all temperatures exceed a threshold (e.g. the hazard condition comprises a plurality of range criteria for respective temperature measurements, and every criterion must be complied with for the hazard condition to be satisfied).

Alternatively or additionally, the plurality of temperature sensors may be used to collect sensor data 10 indicating a temperature gradient across the cylinder 2, that can then be used as a cylinder property for a suitable hazard analysis 1 6.

Although preferred embodiments of the invention have been described, it is to be understood that these are by way of example only and that various modifications may be contemplated.

Claims

1 . A system for safety monitoring of a cylinder for containing compressible fluid, the system comprising a sensor assembly configured to measure and/or detect a cylinder status and output sensor data indicating the cylinder status; and a

processing means configured to:

receive the sensor data and perform a hazard analysis, the hazard analysis comprising determining whether the cylinder status satisfies a hazard condition; and in response to the determination being positive, outputting an electronic signal to an electronic assembly for use in effecting a hazard response action.

2. The system of claim 1 , wherein the hazard condition is based on at least one of: properties of the cylinder, properties of the compressible fluid, properties of a valve assembly attached to the cylinder, and the environment external to the cylinder.

3. The system of claim 1 or claim 2, wherein the hazard condition is a first hazard condition of a plurality of hazard conditions, and the processing means is further configured such that the hazard analysis comprises determining whether the cylinder status satisfies a second hazard condition of the plurality of hazard conditions.

4. The system of claim 3, wherein the electronic assembly comprises a plurality of electronic components and the processing means is further configured to select, based on said hazard analysis, an electronic component from the plurality of electronic components for output of the electronic signal.

5. The system of claim 4, wherein each electronic component is associated with a respective hazard condition of the plurality of hazard conditions, and the

processing means is configured to select an electronic component for output of the electronic signal upon a determination that the cylinder status satisfies the hazard condition associated with that electronic component.

6. The system of any preceding claim, wherein the sensor assembly comprises a plurality of sensors configured to measure and/or detect a respective plurality of cylinder properties, such that the sensor data indicating the cylinder status comprises sensor data indicating each of the plurality of cylinder properties.

7. The system of claim 6, wherein the hazard condition is associated with a first cylinder property of the plurality of cylinder properties, wherein the hazard analysis comprises determining whether the first cylinder property satisfies the associated hazard condition, wherein the hazard condition is a function of at least one other cylinder property of the plurality of cylinder properties.

8. The system of claim 6 or claim 7, wherein the hazard condition is a first hazard condition of a plurality of hazard conditions, each of the plurality of hazard conditions associated with a respective one of the plurality of cylinder properties, wherein the processing means is further configured such that the hazard analysis comprises determining whether each measured cylinder property satisfies the hazard condition associated with that cylinder property.

9. The system of any preceding claim, wherein the sensor assembly comprises a shock sensor configured to measure and/or detect a shock experienced by the cylinder.

10. The system of any preceding claim, wherein the sensor assembly comprises a vibration sensor configured to measure and/or detect a vibration experienced by the cylinder, comprising a measurement and/or detection of at least one of a vibration frequency and a vibration amplitude.

1 1 . The system of any preceding claim, wherein the sensor assembly comprises a orientation sensor configured to measure and/or detect an orientation of an axis of the cylinder relative to a reference axis.

12. The system of claim 1 1 , wherein the hazard condition is satisfied if the orientation of the axis of the cylinder is measured and/or detected to be outside a predetermined value range of angles relative to the reference axis.

13. The system of claim 12, wherein the predetermined value range of angles comprises all angles below a threshold angle relative to the predetermined reference axis.

14. The system of any preceding claim, wherein the sensor assembly comprises at least one temperature sensor configured to measure and/or detect a temperature of the cylinder.

15. The system of claim 14, wherein the sensor assembly comprises a plurality of temperature sensors located at different physical locations with respect to the cylinder configured to measure and/or detect a plurality of cylinder temperatures.

16. The system of any preceding claim, the sensor assembly further comprising a pressure sensor configured to measure and/or detect a pressure of the compressible fluid of the cylinder.

17. The system of any preceding claim, wherein determining whether the cylinder status satisfies a hazard condition comprises determining whether a measured value of the cylinder status is a value outside a predetermined value range associated with the cylinder status.

18. The system of any preceding claim, wherein the electronic assembly comprises at least one of the following electronic components:

an alarm configured to receive the electronic signal and, as the hazard response action, provide an audible warning in response;

a display configured to receive the electronic signal and, as the hazard response action, provide a visual warning in response; a communication device configured to receive the electronic signal and, as the hazard response action, to report the indication of the cylinder status and the result of the hazard analysis; and

a shut-off valve for the cylinder configured to receive the elctronic signal and, as the hazard response action, is provided to the shut-off valve to close the shut-off valve to prevent release of compressible fluid from the cylinder.

19. The system of any preceding claim, further comprising a data storage means, configured to receive the electronic signal and store the sensor data and the result of the hazard analysis.

20. The system of any preceding claim, further comprising a cylinder and the system is integrated into the cylinder.

21 . The system of any preceding claim, wherein the sensor assembly is

configured to perform a failsafe analysis, the failsafe analysis comprising determining whether the cylinder status satisfies a failsafe condition, wherein the sensor assembly is configured to output a failsafe electronic signal to the electronic assembly in response to the failsafe determination being positive.

22. A system substantially as herein described with reference to Figures 1 - 7 of the accompanying drawings.

23. A method for safety monitoring of a cylinder for containing compressible fluid, the method comprising:

at a sensor assembly, measuring and/or detecting a cylinder status and outputting sensor data indicating the cylinder status;

at a processing means, receiving the sensor data and performing a hazard analysis, the hazard analysis comprising determining whether the cylinder status satisfies a hazard condition; and

in response to the determination being positive, outputting an electronic signal to an electronic assembly for use in effecting a hazard response action.

24. The method of claim 23, wherein the hazard condition is based on at least one of: properties of the cylinder, properties of the compressible fluid, properties of a valve assembly attached to the cylinder, and the environment external to the cylinder.

25. The method of claim 23 or claim 24, wherein the hazard condition is a first hazard condition of a plurality of hazard conditions, wherein the hazard analysis comprises determining whether the cylinder status satisfies a second hazard condition of the plurality of hazard conditions.

26. The method of claim 25, wherein the electronic assembly comprises a plurality of electronic components and the method further comprises selecting, based on said hazard analysis, an electronic component from the plurality of electronic components for output of the electronic signal.

27. The method of claim 26, wherein each electronic component is associated with a respective hazard condition of the plurality of hazard conditions, and the method further comprises selecting an electronic component for output of the electronic signal upon a determination that the cylinder status satisfies the hazard condition associated with that electronic component.

28. The method of any of claims 23 - 27, the sensor assembly comprising a plurality of sensors configured to measure and/or detect a respective plurality of cylinder properties, the method further comprising the sensor assembly measuring and/or detecting the plurality of cylinder properties such that the sensor data indicating the cylinder status comprises sensor data indicating each of the plurality of cylinder properties.

29. The method of claim 28, wherein the hazard condition is associated with a first cylinder property of the plurality of cylinder properties, wherein the hazard analysis comprises determining whether the first cylinder property satisfies the associated hazard condition, wherein the hazard condition is a function of at least one other cylinder property of the plurality of cylinder properties.

30. The method of claim 28 or claim 29, wherein the hazard condition is a first hazard condition of a plurality of hazard conditions, each of the plurality of hazard conditions associated with a respective one of the plurality of cylinder properties, such that the hazard analysis comprises determining whether each measured cylinder property satisfies the hazard condition associated with that cylinder property.

31 . The method of any of claims 23 - 30, further comprising, at a shock sensor of the sensor assembly, measuring and/or detecting a shock experienced by the cylinder.

32. The method of any of claims 23 - 31 , further comprising, at a vibration sensor of the sensor assembly, measuring and/or detecting a vibration experienced by the cylinder, comprising measuring and/or detecting at least one of a vibration frequency and a vibration amplitude.

33. The method of any of claims 23 - 32, further comprising, at an orientation sensor of the sensor assembly, measuring and/or detecting an orientation of an axis of the cylinder relative to a reference axis.

34. The method of claim 33, wherein the hazard condition is satisfied if the orientation of the axis of the cylinder is measured and/or detected to be outside a predetermined value range of angles relative to the reference axis.

35. The method of claim 34, wherein the predetermined value range of angles comprises all angles below a threshold angle relative to the predetermined reference axis.

36. The method of any of claims 23 - 35, further comprising, at a temperature sensor of the sensor assembly, measuring and/or detecting a temperature of the cylinder.

37. The method of claim 36, further comprising, at a plurality of temperature sensors of the sensor assembly, measuring and/or detecting a plurality of cylinder temperatures, the plurality of temperature sensors located at different physical locations with respect to the cylinder.

38. The method of any of claims 23 - 34, further comprising at a pressure sensor of the sensor assembly, measuring and/or detecting a pressure of the compressible fluid of the cylinder.

39. The method of any of claims 23 - 38, wherein determining whether the cylinder status satisfies a hazard condition comprises determining whether a measured value of the cylinder status is a value outside a predetermined value range associated with the cylinder status.

40. The method of any of claims 23 - 39, wherein the method further comprises at least one of the following:

at an alarm configured to receive the electronic signal, providing an audible warning as the hazard response action;

at a display configured to receive the electronic signal providing a visual warning as the hazard response action;

at a communication device configured to receive the electronic signal reporting the indication of the cylinder status and the result of the hazard analysis as the hazard response action; and

at a shut-off valve for the cylinder configured to receive the electronic signal, closing the shut-off valve as the hazard response action, the closure of the valve resulting in preventing the release of compressible fluid from the cylinder.

41 . The method of any of claims 23 - 40, further comprising, receiving the electronic signal at a data storage means to store the sensor data and the result of the hazard analysis.

42. The method of any of claims 23 - 41 , further comprising, at the sensor assembly, performing a failsafe analysis, the failsafe analysis comprising determining whether the cylinder status satisfies a failsafe condition, wherein the sensor assembly is configured to output a failsafe electronic signal to the electronic assembly in response to the failsafe determination being positive.

43. A method as substantially as herein described with reference to Figures 1 - 7 of the accompanying drawings.