EP3271640A1

EP3271640A1 - Electronic valve with a generator to generate electricity from compressible fluid flow

Info

Publication number: EP3271640A1
Application number: EP16710226.8A
Authority: EP
Inventors: Colin HADEN; Andy RHODES; Jon Spratley
Original assignee: Linde GmbH
Current assignee: Linde GmbH
Priority date: 2015-03-17
Filing date: 2016-03-17
Publication date: 2018-01-24
Also published as: WO2016146761A1; GB201504449D0

Abstract

An electronic valve assembly for a cylinder containing a compressible fluid. The valve assembly comprises a generator configured to receive a flow of compressible fluid from the cylinder through the electronic valve assembly to generate electricity. The generated electricity powers the electronic valve assembly or increases the charge stored on a store of charge such as a battery.

Description

ELECTRONIC VALVE WITH A GENERATOR TO GENERATE ELECTRICITY

FROM COMPRESSIBLE FLUID FLOW

FIELD OF THE INVENTION

The present invention relates to an electrical generator for an electronic valve for a cylinder containing a compressible fluid. The generator is configured to generate electricity from a flow of the compressible fluid through the electronic valve. The flow of fluid causes a mechanical motion that is converted into electricity. For example, the flow could drive a turbine, or the flow could result in a difference in pressure used to drive a moveable element.

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.

Such cylinders often implement electronic devices or components for the purposes of display or operation. For example, the pressure can be monitored by a pressure gauge utilising an electronic display or electronic sensing elements, or electronic actuators may be incorporated in the valve mechanism. Other examples can be electronic communication devices (e.g. wireless devices) or location sensors (e.g. GPS). Thus, a power source must be provided to the cylinders to allow such electronic components to operate. Given that cylinders are normally portable and employed at locations remote from a power sources, the conventional means to supply power is to provide a battery connected to the cylinder. However, the use of batteries in this manner has disadvantages; conventional batteries are limited in their capacity, meaning that larger batteries are often required for higher power densities. Further, conventional batteries have a limited lifespan and are typically very expensive. These problems are compounded by the nature of their use, where cylinders are often deployed at remote locations for extended periods of time, meaning the power that can be supplied by the battery will not be sufficient to provide a full range of operation over the time period required.

A solution to this problem would be to simply provide a connection to a local power source, such as an attachment to the mains. However, sometimes the location at which the cylinder may be used would not include a local power source. Furthermore, there are instances where use of a local power source would not be desirable, such as when combustible material is stored in the cylinder - if safety provisions are not adequate, a short-circuit and subsequent power surge could be dangerous.

There is thus a need to provide an alternative to simply replacing the batteries of such a device, and the inventors have developed a means to generate electrical power on the cylinder assembly so as to provide a power source without relying on connection to a local power source, which can be unavailable or dangerous, or relying on power stored in a battery, which can be expensive, impractical and/or unsuitable for purpose.

The present invention seeks to provide such a means for generation of electrical power, which provides various advantages over the prior art.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provided an electronic valve assembly, which may be formed as a unitary device in a single housing or a collection of separately housed components attached to one another, for a cylinder containing a compressible fluid, the valve comprising a generator configured to receive at least a portion of a flow of compressible fluid from the cylinder through the electronic valve to generate electricity from the flow of the compressible fluid, the generated electricity being provided to power the electronic valve or charge a store of charge such as a capacitor and/or a battery of the valve. Without reliance on a connection to an external power supply, which may be dangerous, or on power from a capacitor and/or a battery, which has its limitations, the present invention provides greater flexibility and redundancy when operating cylinders and cylinder valves with electronic components.

Advantageously, the generator comprises a turbine, the turbine comprising: an impellor provided in a flow channel of the compressible fluid and configured such that the flow of the compressible fluid through the flow channel causes a rotation of the impellor; and a magnet connected to the impellor such that rotation of the impellor will induce an electrical current in a coil surrounding the magnet. The use of a turbine generator allows for power generation during steady state flow operation of the valve.

Further advantageously, the magnet is provided in the flow channel. This means that a mechanical motion of the compressible fluid can be converted into a mechanical motion of the magnet, and thus generation of power, within the flow channel, obviating a need to pass components through the wall of the flow channel. This consequently results in reduced risk of leakage of fluid. Further

advantageously, the impellor and the magnet are attached to a shaft axially aligned with the flow channel. This configuration provides an optimal arrangement of components. An alternative shaft and impellor arrangement may complicate construction and operation.

In an alternative embodiment to providing the magnet in the flow channel, the magnet may be connected to the impellor by a shaft running through a wall of the flow channel. In this embodiment, the magnet and other generator components can be accessible to the user without having to disassemble the flow channel, making maintenance and installation easier.

In an additional advantageous embodiment of the present invention, the generator comprises a moveable element with a first surface and a second surface opposite the first surface, wherein: the first surface is in fluid communication with a flow channel of the compressible fluid such that the first surface is at a fluid pressure; and the second surface is provided at a reference pressure; such that a difference in pressure between the fluid pressure and the reference pressure results in a pressure force applied to the moveable element; and wherein the generator is configured to provide a balancing force to the moveable element, the balancing force so as to oppose the pressure force, such that a change in the fluid pressure results in a movement of the moveable element, wherein said movement is converted by the generator into electrical current. The generation of electrical energy from a difference in pressure is an alternative means to provide mechanical motion from the flow of a compressible fluid, and is particularly useful during periods where flow is discontinuous - i.e. the flow starts and stops again. In such circumstances, a continuous flow generator will have reduced efficiency.

Advantageously, the generator is configured to provide the balancing force by means of a balancing element connected to the moveable element. The balancing element may be a spring or similar. A physical component is readily adjustable allowing for customisable balancing forces to be applied to the generator.

Alternatively, or additionally, the generator is configured to provide the balancing force by the first surface and second surface being arranged vertically opposite such that the balancing force is a gravitational force. Gravitational force is a well-known quantity, and through the provision of suitable weighting a customisable balancing force may be provided.

In a further advantageous embodiment of the present invention, the second surface is in fluid communication with the environment external to the valve, such that the reference pressure is the ambient pressure of the external environment. This embodiment provides a relatively simple construction, allowing for a well- defined pressure value (e.g. atmospheric pressure) to serve as a reference value. Any compressed fluid will be at a higher pressure than this, meaning a flow of such fluid will result in the required pressure force. Alternatively, the flow channel comprises a first portion and a second portion such that the fluid connection of the first surface to the flow channel is a connection to a first portion of the flow channel and the fluid pressure is a first fluid pressure; the second surface is in fluid

connection with second portion of flow channel such that the reference pressure is a second fluid pressure, wherein the flow channel is configured such that the second fluid pressure is different to the first fluid pressure. By providing the two pressure values from the flow channel, one obviates the requirement for fluid communication of generator components with an external environment, reducing the risk of leakage of the compressible fluid to that environment.

In a further advantageous embodiment, the second portion of the flow channel has a different cross sectional area to the first portion of the flow channel, such that a flow of compressible fluid from the first portion to the second portion results in the difference between the first fluid pressure and the second fluid pressure. This embodiment utilises the well-known principle of the Venturi effect, a robust physical law where a difference in pressure results from the claimed features. This

configuration is therefore a reliable means to effect a difference in pressure in the flow channel.

Advantageously, the moveable element is a diaphragm or a piston. Each has different benefits; for example, diaphragms can be sealed to another component and do not require the relative movement of abutting surfaces, which can result in leakage. However, pistons are stronger and more robust.

In another advantageous embodiment, the generator is configured such that a movement of the moveable element adjusts a dimension of a flow channel interface, being an interface between the first portion of the flow channel and the second portion of the flow channel, such that a movement of the moveable element controls the flow between the first portion of the flow channel and the second portion of the flow channel. In this embodiment, the generator also acts as a regulator, and a pressure difference between the first and second surfaces is maintained by a restriction of the flow through the flow channel interface.

Advantageously, the generator comprises the flow channel interface such that a flow of compressible fluid through the flow channel includes a flow of the

compressible fluid through the generator. Providing the generator as part of the flow channel simplifies construction. For example, the generator can simply be attached (fixedly or otherwise) to the outlet of the valve.

Further advantageously, the moveable element comprises a secondary channel and the generator is configured such that a flow of the compressible fluid through the flow channel includes a flow of the compressible fluid through the moveable element. Providing the flow through the moveable element means that the other parts of the generator do not need to be adjusted to permit flow - for example, the magnets can be solid magnets, which increases magnetic field strength.

Optionally, the moveable element is a shuttle, which is an element configured to translate backwards and forwards within a channel.

Advantageously, the balancing element is adjustable to provide an adjustable balancing force. By adjusting the balancing force, the generator can be customisable whether it is to regulate the flow, or to provide an optimum balance to a pressure force for a given pressure of compressible fluid.

Optionally, the valve is a shut-off valve. Providing the generator to a shut-off valve means that the generator is, for all intents and purposes of the end user, integrated to the cylinder. This is because the shut-off valve is a primary valve regulating all fluid flow from the cylinder, which is not typically removed by the end user. Alternatively, the valve is a valve assembly comprising an electronic shut-off valve and a secondary valve attached to the shut-off valve. This provides

adaptability advantages, such as interchange of parts to allow the use of a generator with different components and different cylinders.

In a further advantageous embodiment, the secondary valve comprises the generator and the generated electricity is provided from the secondary valve to the electronic shut-off valve to power the electronic shut-off valve. Providing the generator on a different component than the shut-off valve to power the shut-off valve allows for redundancy and adaptability, for example to supplement a power source or generator on the shut-off valve.

Optionally, the generator provides power to the electronic valve by means of a cable connection. Alternatively, or additionally, the generator provides power to the electronic valve by means of inductive or capacitative coupling. Different ways to supply the power may be suitable in different circumstances. For example, physical cables may not be suitable in hazardous environments when they can get snagged. Physical cables can be, however, more reliable in providing a robust physical connection for the flow of power.

Advantageously, the electronic valve further comprises a battery configured to be charged by the generated electricity. The generator may be configured, for example, to operate to continually top up the battery rather than directly power the valve. This may be suitable for instances where the generator alone does not provide enough energy to power the electronic components employed on the valve.

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 side view of a cylinder assembly comprising an electronic valve in accordance with the present invention.

Figure 2A is a side view of a turbine generator for use with the electronic valve of the present invention.

Figure 2B shows an end view of a pipe and coil assembly used in the turbine generator of Figure 2A.

Figure 2C is a side view of an additional configuration of the turbine generator illustrated in Figure 2A.

Figure 2D is a side view of an alternative turbine generator for use with the electronic valve of the present invention.

Figure 3 is a side view of an external pressure reference generator for use with the electronic valve of the present invention.

Figure 4 is a side view of a Venturi delta P generator for use with the electronic valve of the present invention.

Figure 5A is an illustration of a shuttle generator for a compressible cylinder valve in accordance with another embodiment of the present invention. The shuttle generator is shown in a first configuration where there is no fluid flow through the generator.

Figure 5B is an illustration of the shuttle generator of Figure 5A in a second configuration, where there is a fluid flow through the shuttle generator.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

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

Figure 1 illustrates an electronic valve assembly for a cylinder 1 containing a compressible fluid 10. The valve assembly comprises an electronic valve 3 and a generator 5 configured to receive at least a portion of a flow 12 of compressible fluid 10 from the cylinder through the electronic valve. The electronic valve may be an assembly formed as a unitary device having a single housing that encloses both the valve 3 and the generator 5, or may be an assembly in which the valve 3 and the generator 5 are housed separately. In the description that follows, the generator 5 is described as a part of the valve 3, and thus the assembly is a unitary device, however this is not essential. The generator 5 is configured to generate electricity from the flow 12 of the compressible fluid 10. The generator is configured such that the generated electricity is provided to power the electronic valve 5 or charge a capacitor or, as shown, a battery 13 of the valve 5, through means of a suitable connection between the generator 12 and the valve 5 and/or battery 13.

Additionally, the generator may be configured to provide electrical power to other components. For example, the electronic valve 5 itself may be fitted with an electronic component 7a (for example, an electronic display). Additionally, the cylinder 1 may be fitted with another electronic component 7b (e.g. an electronic display for the cylinder). The generator may be configured, such as by means of a detachable electrical connection 8, to provide power to one or both of these examples, as well as other electrical components.

In the illustrated example of Figure 1 , the electrical generator may be connected to an electrical actuator 9 of the valve 5 via actuator electrical connection 1 1 to provide power for operation of the electrical actuator 9. In the illustrated embodiment of Figure 1 , the actuator 9 is a shut-off actuator, configured to move a piston 14a relative to a seat 14b between an open configuration (as illustrated in Figure 1 ) that permits the flow 12 of compressible fluid 10 through the valve 5, to a closed configuration where the piston 14a abuts the seat thus preventing the flow 12 of compressible fluid 10 through the valve.

In the illustrated embodiment of Figure 1 , the generator 5 is provided at a location where it is arranged to receive the flow 12 of the compressible fluid 10 downstream of the electrical actuator 9. It is to be understood that the generator 5 may be disposed at alternative locations with respect to the valve 5, so long as the generator 5 is arranged to receive at least a portion of the flow 12 of the

compressible fluid 10. For example, the generator 5 may be located upstream of the electrical actuator 9, proximate to the top of the cylinder 1 - as illustrated by the dashed line 5a in Figure 1 .

The functionality of the generator 5 is such that electricity is generated from the flow 12 of the compressible fluid 10 and can be achieved in multiple ways.

Exemplary embodiments of how the generator 5 achieves this are described below. Figures 2A - 2D illustrate exemplary embodiments of the invention. Figures 2A, 2C and 2D illustrate a generator 5 for the generation of electricity from a flow 12 of compressible fluid 10, where the generator 5 is a turbine generator 5. Specifically, the generator 5 comprises a turbine 20. The turbine comprises an impellor 22 provided in a flow channel 24 of the compressible fluid 10, where the flow channel may be a channel through a pipe 21 . The impellor 22 is configured such that the flow 12 of the compressible fluid 10 through the flow channel 24 causes a rotation of the impellor 22. The impellor 22 is shown schematically, and it is understood that multiple different impellor types can be employed as impellor 22 of the illustrated embodiments such that the flow 12 of the compressible fluid 10 causes the impellor 22 to rotate. Examples of suitable impellors are open impellors, semi-open impellors, closed impellors and shrouded impellors. The generator 5 further comprises a magnet 26 connected to the impellor 22 such that rotation of the impellor 22 will induce an electrical current in a coil 28 surrounding the magnet 26. The illustrated embodiments operate under the principle of electromagnetic induction well known in the art, where a variation in magnetic field across a coil of a

conducting material will induce an electrical current in that coil. Specifically, the rotation of the impellor 22 causes a mechanical movement of the magnet 26, resulting in a varying magnetic field applied to the coil 28. In the illustrated embodiments, the magnet 26 is connection to the impellor by means of a shaft 30, and rotation of the impellor 22 causes the shaft 30 to rotate around its longitudinal axis. The magnet 26 therefore also rotates around the longitudinal axis of the shaft 30. Nevertheless, it is to understood that the magnet may be coupled to the impellor 22 by other means such that a rotation of the impellor causes mechanical motion of the magnet 26 such that a varying magnetic field is produced across the coil 28 as a result of the flow 12 of the compressible fluid 10 through the flow channel 24. The turbine 20 is configured such that it will work and generate electricity when the flow 12 is directed in either direction through the flow channel 24. As such, in the illustrated embodiments of Figures 2A, 2C and 2D, flow 12 is shown as being possible in either direction.

The strength of magnet 26 used and the number of windings of the coil 28 can be varied to optimise the electric current being produced. Advantageously, and as illustrated in Figures 2A, 2C and 2D, the generator 5 may comprise multiple magnets 26, where rotation of the impellor 22 causes a mechanical motion of the magnets 26, and in the illustrated embodiment, a rotation of all magnets 26 around the

longitudinal axis of the shaft 30. Employing multiple magnets has the advantage of a increased magnetic field strength an extended magnetic field, allowing for a larger coil to be used and more electricity to be generated. Where 'magnet' is used within this specification, it is to be understood that this may also mean multiple magnets. Additionally, there may be provided a ferromagnetic sleeve 27 around the coil 28.

In the illustrated embodiment of Figure 2A, the magnet 26 is provided in the flow channel 24. In this embodiment, the rotation of the impellor 22 causes

movement of the magnet 26 within the flow channel 24. The coil is provided in a manner such that this movement of the magnet 26 induces an electrical current in the coil 28. In the illustrated embodiment, the coil 28 has windings 25 provided with respect to the flow channel 24 such that the winding direction of the coil 28 is parallel with the length of the flow channel 24. This may be achieved by a plurality of windings circumferentially arranged around the pipe 21 , where the windings 25 are constructed such that a length of wire runs down the length of the pipe 21 before running back up the length of the pipe 21 at a different point on the circumference of the pipe 21 . This arrangement is illustrated in Figure 2B, which shows a cross- section of an end view of an assembly of the pipe 21 , coil 28 and ferromagnetic sleeve 27. . However, it is to be understood that any suitable arrangement of windings can be provided such that electrical current is generated by movement of the magnet 26 resulting from a rotation of the impellor 22. Optionally, the impellor 22 and the magnet 26 are attached to a shaft 30 axially aligned with the flow channel 24. In this embodiment, the impellor 22 is a radial flow impellor, where a rotation of the impellor 22 is caused by the flow 12 being along the axis of the shaft 30. Thus, the flow 12 causes a rotation of the shaft 30 and consequently a rotation of the magnet 26 around the axis parallel with the direction of flow 12 within the flow channel 24. The shaft 30 is attached by internal bearings 32 to the pipe 21 that defines the flow channel 24. The internal bearings 32 allow for the rotation of the shaft 30 around its axis while still maintaining an attachment to the pipe 21 . Further advantageously, the impellor 22, shaft 30, internal bearings 32 and/or the magnet 26 can be formed as a single unit. Notably, the illustrated embodiment of Figure 2A does not require the shaft 30 to pass through a wall of the flow channel 24 and pipe 21 , but instead provides the components of the turbine 20 within the flow channel 24. This is advantageous, as passing any components through the wall of a flow channel 24 will introduce structural weaknesses and the possibility of leakage of the compressible fluid 10, avoided by the embodiment of Figure 2A.

Figure 2C illustrates a configuration of the above described turbine generator 5 of Figure 2A. In this alternative configuration, the generator 5 (as described above in reference to Figure 2A) is provided in a bypass channel 29, which branches off from the flow channel 24, where the flow channel 24 is a primary flow channel in this embodiment. A flow of compressible fluid flows from the primary flow channel into the bypass channel through a bypass channel entrance, via the bypass channel 29 and back to the primary flow channel through a bypass channel exit. Provided within the primary flow channel is a flow restriction 31 , which is arranged in the primary flow channel between the bypass channel entrance and the bypass channel exit, so as to regulate the flow through the primary flow channel and the flow through the bypass channel (and hence through the generator 5).

In the illustrated embodiment of Figure 2D, the magnet 26 is provided external to the flow channel 24, and the rotation of the impellor 22 causes movement of the magnet 26 at a location external to the flow channel 24. For example, the generator 5 is constructed such that the magnet 26 is arranged in a chamber 34 attachable to the flow channel 24, and movement of the impellor causes movement of the magnet 26 in the chamber 34. The coil is provided in a manner such that this movement of the magnet 26 induces an electrical current in the coil 28. In the illustrated embodiment of Figure 2D, the coil 28 has windings provided with respect to the chamber 34 such that the winding direction is along the length of the chamber 34. A plurality of windings may be provided with respect to the chamber 34 in the same manner that a plurality of windings is provided with respect to the flow channel in the embodiment of Figures 2A - 2C. Optionally, the magnet 26 is connected to the impellor 22 by a shaft 30 running through a wall of the flow channel 24. In this embodiment, the impellor 22 is an axial flow impellor, where a rotation of the impellor 22 is caused by the flow 12 being in a direction perpendicular to the longitudinal axis of the shaft 30. Consequently, the flow 12 causes rotation of the shaft 30 and consequently a rotation of the magnet 26 around an axis perpendicular with the direction of flow 12 within the flow channel 24. The shaft 30 is attached by wall bearings 36 to the pipe 21 that defines the flow channel 24. The wall bearings 36 allow for a rotation of the shaft 30 while still maintaining attachment to the pipe 21 , and serve as a seal to the aperture in the wall through which the shaft 30 runs to prevent leakage of the flow of fluid through the aperture. Further advantageously, the impellor 22, shaft 30, wall bearings 36 and/or the magnet 26 can be formed as a single unit.

Notably, the illustrated embodiment of Figure 2D provides generator components in an environment external to the pipe 21 and flow channel 24 (such as the magnet 26 and shaft 30. This is advantageous, as in the event of a fault or problem with said generator components, a user or technician can readily access these components to inspect, maintain or replace them without having to disconnect the valve 3, generator 5 and the constituent internal components.

While power will be generated by the above described turbine generators when any flow is present in the flow channel 24, maximum power is generated when a continuous flow of compressible fluid is provided. If, for example, a valve is repeatedly turned off and on, the energy harvested from the embodiments of Figures 2A - 2D may not be optimum.

Below will be described embodiments of the present invention where the generator is configured to harvest energy from discontinuous flow, such as in circumstances when the valve 3 is turned off and on again repeatedly. Figures 3, 4, 5A and 5B illustrate exemplary embodiments of discontinuous flow generators of the present invention. In these embodiments, the generator 5 is configured to generate electrical current from a mechanical motion that results from a difference in pressure that is present within the flow channel 24. In these illustrated embodiments, the electronic valve 3 comprises a generator 5 for the generation of electricity from a flow 12 of compressible fluid 10, wherein the generator 5 comprises a moveable element 50 with a first surface 51 and a second surface 52 opposite the first surface 51 . The first surface 51 is in fluid communication with a flow channel 24 of the compressible fluid 10 such that the first surface is at a fluid pressure P1 . The fluid pressure is a pressure within the flow channel 24, and when the compressible fluid 10 is flowing through the flow channel 24 the fluid pressure is the pressure of that compressible fluid. Similarly, when the compressible fluid 10 is not flowing through the flow channel (e.g. the valve is shut), the fluid pressure P1 is an ambient pressure within the flow channel 24. The second surface 52 is provided at a reference pressure P2. Different ways in which this reference pressure may be achieved are described below in respect to the illustrated embodiments of Figures 3, 4, 5A and 5B. The generator 5 is configured such that a difference in pressure (i.e. P1 - P2) between the fluid pressure P1 and the reference pressure P2 results in a pressure force F1 applied to the moveable element 50. Additionally, the generator 5 is configured to provide a balancing force F2 to the moveable element 50. The balancing force F2 is provided so as to oppose the pressure force F1 , and such that a change in the fluid pressure P1 results in a movement of the moveable element 50. Specifically, the change in fluid pressure P1 results in a change in the difference in pressure between the flow channel 24 and the reference pressure P2, which will in turn affect the pressure force F1 on the moveable element. An increase in fluid pressure P1 will increase the pressure force F1 , and a reduction in fluid pressure P1 will reduce the pressure force F1 . Consequently, the net difference in the forces acting on the moveable element 50 (i.e. F1 - F2) will result in a movement of the moveable element. The generator 5 is configured such that said movement is converted by the generator 5 into electrical current. This may be achieved through electromagnetic induction as described above in reference to Figures 2A and 2B. Specifically, in the exemplary embodiments, described below in more detail, the generator 5 comprises a coil 28 and a magnet 26 attached to the moveable element 50 such that a movement of the moveable element 50 causes a varying magnetic field across the coil 28, inducing electrical current.

Advantageously, the generator 5 is configured to provide the balancing force F2 by means of a balancing element 54 connected to the moveable element. In the illustrated embodiments of Figures 3, 4, 5A and 5B, this balancing element is a spring attaching the moveable element 50 to the generator 5, which will provide a resistive force against any motion that either compresses or expands the spring from a natural state. Nevertheless, alternative components can be employed as balancing elements, such as any form of urging means, that provide a bias or balancing force that serves to oppose a mechanical motion of the moveable element 50 and/or motion of the moveable element 50 away from a particular position. Alternatively or additionally, the generator 5 is configured to provide the balancing force by the first surface 51 and second surface 52 being arranged vertically opposite such that the balancing force F2 is a gravitational force.

Optionally, weights (not shown) may be applied to the moveable element 50 to increase the gravitational force acting downwards and against the pressure force F1 .

Figures 3, 4, 5A and 5B illustrate generator 5 configurations that provide alternative ways to provide the reference pressure P2. These configurations provide advantages and benefits in implementing the operating principle described above, but it would be understood by the skilled person that its implementation is not limited to the embodiments described below.

Figure 3 illustrates a generator 5, denoted herein as an external pressure reference generator, the generator 5 comprising a moveable element 50 where the first surface 51 is in fluid communication with the flow channel 24 and the second surface 52 is in fluid communication with the environment external to the valve 3, such that the reference pressure P2 is the ambient pressure of the external environment. The environment external to the valve 3 may, for example, be the environment external to the cylinder such as a laboratory. In this case, the ambient pressure is atmospheric pressure (101 .325 kPa). In the embodiment of Figure 3, the moveable element 50 is arranged to translate within a chamber 56, and is connected to a wall of the chamber 56 by the balancing element 54. The magnet 26 is connected to the moveable element 50 and the coil 28 is wrapped around the outside of the chamber 56 such that a movement of the moveable element 50 results in the movement of the magnet 26 within the coil 28, generating electricity. The second surface 52 is provided at the reference pressure P2 by means of an aperture 58 provided in the chamber 56, allowing fluid communication between the second surface 52 and the external environment at the reference pressure P2.

In this embodiment, the moveable element 50 is preferably attached to walls of the chamber 56 in a manner to prevent leakage of compressible fluid 10 from the flow channel, but still allows movement of the moveable element 50. For example, the moveable element 50 may be a plate or piston connected to the chamber by bearings 56. Alternatively, the moveable element 50 may be a membrane fixed to the walls of the chamber and the moveable element 50 moves by a deformation of the membrane surface. Figures 4, 5A and 5B illustrate further exemplary embodiments of the present invention, where the second pressure P2 is not referenced from an external source, but rather from the flow channel. Specifically, a generator 5 comprises a moveable element 50 where the first surface 51 of the moveable element 50 is in fluid communication with the flow channel 24, but the second surface 52 is also in fluid communication with the flow channel 24. In these embodiments, the flow channel 24 comprises a first portion 62 and a second portion 64. The fluid connection of the first surface 51 to the flow channel 24 is a connection to a first portion 62 of the flow channel 24 and the fluid pressure P1 is a first fluid pressure. Additionally, the second surface 52 is in fluid connection with second portion 64 of flow channel 24 such that the reference pressure P2 is a second fluid pressure. The flow channel 24 is configured such that the second fluid pressure is different to the first fluid pressure; examples of this will be described below with reference to Figures 4, 5A and 5B. As described above with reference to Figure 3, the difference in pressure (P2 - P1 ) at the opposite surfaces of the moveable element 50 results in a pressure force F1 being applied to the moveable element 50. The moveable element 50 is subject to a balancing force F2 to oppose the pressure force F1 . This balancing force may be provided by a balancing element 54. Thus, a change in either or both of the first fluid pressure and second fluid pressure will result in a change in the pressure force and consequently will result in a movement of the moveable element 50. The generator further comprises a magnet 26 attached to the moveable element 50 such that the movement of the moveable element 50 causes a variation in magnetic field at a coil 28, thus inducing an electrical current.

Figure 4 illustrates an exemplary embodiment of the above principle. The moveable element 50 is disposed within an element channel 70, wherein the element channel 70 is connected to the first portion 62 of the flow channel 24 by means of a first branch 66, and the element channel is connected to the second portion of the flow channel 24 by means of as second branch 68. Thus, the first branch 66 defines a channel through which the first surface 51 is in fluid

communication with the first portion 62 of the flow channel 24, and the second branch 68 defines a channel through which the second surface 52 is in fluid communication with the second portion 64. The moveable element is configured such that a movement of the moveable element 50 is a translation along the element channel 70. The coil 28 is provided such that it is wound around the element channel 70, and a translation of the moveable element 50 within the element channel results in the magnet 26 translating along the longitudinal axis of the coil 28.

Preferably, the moveable element 50 forms a seal with the sidewall of the element channel 70 and the seal is configured such that there is no flow between the first branch 66 and second branch 68 through the element channel 70, even when the moveable element 50 undergoes a translation within the channel 70. Thus, the pressure at the first surface 51 will track the first fluid pressure in the first portion 62 and the second surface 52 will track the second fluid pressure in the second portion 64.

The manner by which the first fluid pressure is different to the second fluid pressure is founded in the 'Venturi effect', and is the physical principle underlying the embodiment of Figure 4, thus the generator 5 of Figure 4 is denoted as a Venturi delta P generator 5c. The Venturi effect is a physical phenomenon where when a fluid flowing in a vessel moves from a relatively wider cross-section to a relatively narrower cross-section, the fluid pressure in the relatively narrower cross-section will be less than in the relatively wider cross-section. The same principle works in reverse - when fluid flows from a relatively narrower cross-section to a relatively wider cross-section, the pressure in the relatively wider cross-section will be greater than in the relatively narrower cross-section.

This principle is applied in the illustrated embodiment, where the flow 12 of the compressible fluid 10 passes successively through several portions of the flow channel 24, namely an entry portion 61 , the first portion 62 and the second portion 64, where each portion has a different cross-sectional area such that the flow will be at different pressures in each portion as a result of the Venturi effect. Notably, the second portion 64 of the flow channel 24 has a different cross sectional area to the first portion 62 of the flow channel 24. Thus, a flow 12 of compressible fluid 10 from the first portion 62 to the second portion 64 results in the difference in pressure (P2 - P1 ), between the first fluid pressure and the second fluid pressure, resulting in the movement of the moveable element 50, as described above. Figure 4 illustrates the first portion 62 having a narrower cross-section than the second portion 64, but it is to be understood that the opposite could equally apply; namely the first portion 62 having a greater cross-sectional area than the second portion 64. This would result in the pressure force F1 being applied to the moveable element 50 in the opposite direction. The balancing element 54 may still be configured to oppose the reversed pressure force F1 - notably a spring will resist a force applied to both compress the spring and stretch the spring.

It is to be understood that the result of a difference in pressure between the first portion 62 and the second portion 64 is a result of the cross-sectional areas being of different values. However, the specific value of the first fluid pressure and the specific value of the second fluid pressure will depend on the actual cross sectional area of the first portion 62 and the actual cross-sectional area of the second portion 64. Furthermore, the value will depend on the velocity of the compressible fluid initially being provided to the first portion 62 of the flow channel 24. For example, in the illustrated embodiment, the compressible fluid 10 flows into the first portion 62 from the entry portion 61 , and the fluid which itself has a specific cross-sectional area. The entry portion 61 of Figure 4 is shown with a larger cross sectional area than the first portion 62, with the flow 12 of compressible fluid 10 being at an entry pressure P0. The entry pressure is determined, at least in part, by the pressure of the compressible fluid in the cylinder 1 to which the valve is attached, the cross-sectional area of entry portion 61 , and the extent to which any valve actuator upstream of the entry portion is open, partially open or closed. Thus, through appropriate modification and adjustment of the dimensions of the first portion 62, second portion 64 and entry portion 61 , a manufacturer could appropriately tune the precise values for a pressure force to be exerted on the moveable element 50 to optimisation of translation of the moveable element 50 in element channel 70 for the generation of power. While, in the illustrated embodiment, first portion 62 and second portion 64 must have different cross-sectional areas, it could nevertheless be understood that the entry portion 61 and the first portion 62 may be contiguous with the same cross-sectional area, thus being provided at the same pressure.

Different alternatives may be implemented as the moveable element 50. For example, the moveable element 50 may be a shuttle, as illustrated in Figure 4, but could also be implemented as, for example, a diaphragm, with a principle of operation with respect to the coil 28 as detailed above with respect to Figure 3, or a piston. It is understood that other alternatives for the moveable element 50 could be envisioned by a skilled person, where that moveable element 50 can be moved as a result of a force imparted from a difference in pressure at opposing surfaces of the moveable element 50.

Figures 5A and 5B illustrate another exemplary embodiment of the present invention, where a generator 5 is a shuttle generator 5d comprising a moveable element 50. In the illustrated embodiments, the moveable element is a shuttle 50d, but it is understood that other suitable moveable elements may be employed. The first surface 51 of the shuttle 50d is in fluid communication with a first portion of the flow channel 24 so as to be at a first fluid pressure, and the second surface 52 is in fluid communication with a second portion 64 of the flow channel 24 so as to be at a second fluid pressure. In a manner similar to the embodiments described above in respect of Figures 3 and 4, in the embodiment of Figures 5A and 5B the first and second fluid pressures are different, imparting a pressure force F1 on the shuttle 50d to result in a movement of the shuttle 50d. The shuttle 50d is attached to a magnet 26, such that a movement of the shuttle 50d moves the magnet 26 to create a varying magnetic field across a coil 28 to induce electric current. However, in the embodiment of Figures 5A and 5B, the movement of the shuttle 50d regulates the flow 12 of compressible fluid 10 between the first portion 62 of the flow channel 24 and the second portion 64 of the flow channel 24. Consequently, the shuttle generator 5 serves both as a generator of electricity but also a regulator of the flow 12 of compressible fluid 10 through the flow channel. This is especially

advantageous as the physical space on the top of a compressible fluid cylinder 1 is limited, and a user will be restricted in the number of components and attachments that he can attach to the valve 3. A component with two functions such as the shuttle generator 5d would save space and provide cost and efficiency savings.

In the illustrated embodiment of the shuttle generator 5d of Figure 5A and Figure 5B, the generator 5 is configured such that a movement of the moveable element 40 adjusts a dimension of a flow channel interface 85. The flow channel interface 85 is the part of the flow channel connecting the first portion 62 to the second portion 64 of the flow channel, such that a flow 12 of compressible fluid 10 through the flow channel 24 will travel via the flow channel interface 85. Thus the flow channel interface can be considered an interface between the first portion 62 of the flow channel 24 and the second portion 64 of the flow channel 24. By adjusting a dimension of the flow channel interface 85, the volume of compressible fluid 10 passing from the first portion 62 to the second portion 64 will change. Consequently, a movement of the shuttle 50d controls the flow 12 between the first portion 62 of the flow channel 24 and the second portion 64 of the flow channel 24. This will in turn affect the values for the first fluid pressure and the second fluid pressure and therefore the resultant pressure force F1 on the shuttle 50d, as described above with respect to other embodiments.

The shuttle generator 5d further comprises a balancing element 54 (e.g. an urging means such as a spring) arranged to provide a balancing force F2 to the shuttle 50d to resist the pressure force F1 . When there is a resultant force acting upon the moveable element (i.e. the difference between the pressure force F1 and the balancing force F2 is not zero), a movement of the shuttle 50d will occur and thus result in the generation of electricity in the coil 28. Figures 5A and 5B illustrate two configurations of the shuttle generator 5d in use. Specifically, Figure 5A illustrates a position of the shuttle 50d where there is no flow through the flow channel interface 85, and Figure 5B illustrates a position of the moveable element where there is a flow through the flow channel interface 85. The shuttle generator 5d moves from the first configuration to the second configuration when the pressure force F1 is greater than the balancing force being provided by the balancing element 54, and will move back toward the first configuration from the second configuration when the pressure force is less than the balancing force F2. For example, this may occur when the first fluid pressure in the first portion 62 drops. Change from the first configuration to the second configuration results in the generation of electricity in the shuttle generator 5.

The balancing element 54 may be configured such that the force F2 can be varied. For example, the balancing element 54 is adjustable to provide an adjustable balancing force, such as by means of an adjustment handle attached to the generator (not shown) to adjust the balancing element. Thus, a specific flow 12 of compressible fluid 50 may be regulated by the shuttle generator 5d. Due to the restriction of flow from the first portion 62 to the second portion 64, the second fluid pressure will always be lower than the first fluid pressure. The difference in pressure will be greatest when a flow 12 is first provided to the shuttle generator 5 (as illustrated in Figure 5A), when the second fluid pressure is the pressure of any residual or ambient fluid present in the second portion of the flow channel. The difference will, however, decrease as compressible fluid 10 flows into the second portion 64 as a result of the movement of the shuttle 50d. This reduction in the pressure force will again result in a movement of the shuttle 50d, but in the opposite direction thus reducing the flow and increasing the pressure force. The movement of the shuttle 50d within the generator will therefore be of a damped oscillatory form, settling on an equilibrium value when the pressure force F1 and the balancing force F2 are equal.

Advantageously, and as shown in Figures 5A and 5B, the generator 5 comprises the flow channel interface 85. The flow 12 of the compressible fluid 10, being the flow from the cylinder 1 to the intended end user, flows via both the first portion 62 and the second portion 64 of the flow channel 24 and thus a flow 12 of compressible fluid 10 through the flow channel 24 includes a flow 12 of the compressible fluid 10 through the generator 5d. For example, the shuttle generator 5d comprises a shuttle chamber 79 housing the shuttle 50d, and the movement of the shuttle 50d within the shuttle chamber 79 is a translation of the shuttle 50d along the chamber. The flow 12 of the compressible fluid flows from a pipe 21 into the shuttle chamber 79 via an inlet 81 . In this embodiment, the first portion 62 of the flow channel 24 is the portion of the flow channel 24 in the pipe, and the second portion of the flow channel 24 includes the portion of the flow channel passing through the generator. The interface between the first portion 62 and the second portion 64 comprises the inlet 81 . The shuttle chamber 79 comprises an outlet 80 for the passage of the flow 12 of compressible fluid 10. Advantageously, the generator is configured that all of the flowing compressible fluid 10 in the pipe flows through the inlet 81 and the outlet 80, such that all of the flow 12 of the compressible fluid 10 from the cylinder 1 flows via the shuttle generator 5d.

Advantageously, the movement of the shuttle 50d controls the flow 12 of compressible fluid 10 at the interface 85 by adjusting a distance between the first surface 51 of the moveable element and the inlet 81 of the shuttle chamber 79. The shuttle 50d is moveable from a configuration where the first surface 51 completely covers the inlet 81 , thus preventing the flow 12 of compressible fluid 10, to a number of configurations where there is a separation distance between the first surface 51 and the inlet 81 , where the size of that distance determines the size of an opening through which compressible fluid 10 may flow from the first portion 62 to the second portion 64 of the flow channel. The illustrated embodiment shows a flat first surface, but this is exemplary only. It is to be understood that the first surface 51 may be provided with another shape, with the inlet 81 configured in a corresponding shape to receive the first surface.

The volume of the flow 12 is regulated by the opening provided at the interface, as described above, but the shuttle generator 5 requires a means by which the compressible fluid 10 must flow between the inlet 81 and the outlet 80 of the shuttle chamber 79. Advantageously, the shuttle generator 5d is configured such that the flow 12 of compressible fluid 10 also flows through the shuttle 50d. In this advantageous embodiment, the shuttle 50d comprises a secondary channel 83 and the generator is configured such that a flow of the compressible fluid 10 through the flow channel 24 includes a flow 12a of the compressible fluid 10 through the shuttle 50d. By providing flow through the shuttle 50d, solid magnets 26 may be provided proximate to the edge of the shuttle chamber 79 and thus the coil 28, which is advantageously wrapped around the chamber 79 such that it is at the closest distance to the moving magnet 26.

The above described discontinuous flow embodiments of Figures 3, 4, 5A and 5B operate through the provision and cessation of flow causing a motion of the moveable element 50. If flow is in a steady state, then there will be no motion of the moveable element 50 as the pressure difference will be constant and the pressure force F1 and balancing force F2 will balance, leaving the system in a state of equilibrium. However, and as stated above, these embodiments are especially useful when the flow is turned off and on again, such as when a cylinder is used to supply gas for welding. Upon a cessation of flow 12, the moveable element 50 will move to rebalance the forces that it is subject to, resting in a new equilibrium position. Resumption of flow will again move the moveable element 50 to a new position, and every movement of the moveable element will generate electricity through inductance in the coil.

The above described embodiments of both the continuous flow generators of Figures 2A - 2D and the discontinuous flow generators of Figures 3, 4, 5A and 5B are configured to be provided within a valve 3 for a cylinder 1 , as described above, for advantageous reasons such as compactness of the valve assembly and also to ensure proximity of a power source to the valve 3 to ensure provision of electrical power to the valve 3. The generator 5 is suitable for use with a number of valves. For example, the valve 3 is a shut-off valve. A shut-off valve is understood to be the primary valve that is attached to a cylinder 1 to regulate all flow entering and leaving the cylinder 1 . These valves are not removed by the end user, which means that in this advantageous embodiment, the cylinder 1 will always be provided with an integrated power source. In contrast, if the generator 5 is provided in a removable component of a valve assembly, then the user may be required to detach the valve comprising the generator for another purpose (e.g. to fit a more bespoke valve assembly component in its place). The user would therefore need to sacrifice power generation in making this adaption.

However, in an alternative advantageous embodiment, where the valve 3 is a valve assembly comprising an electronic shut-off valve and a secondary valve attached to the shut-off valve. Providing the generator as part of a valve assembly rather than exclusively in a shutoff valve can have its own advantages. For example, parts of the valve assembly, including the generator, may be detached and provided on a cylinder that does not have a generator 5 already, facilitating harvesting of energy that would otherwise be wasted. Additionally, parts of an assembly can be replaced if they break, simplifying maintenance for the user. In a further

advantageous embodiment, the secondary valve comprises the generator 5 and the generated electricity is provided from the secondary valve to the electronic shut-off valve to power the electronic shut-off valve. This example demonstrates a high level of adaptability, meaning that the generator 5 is not limited to providing power exclusively to the component to which it is attached. This means, for example, that for a valve assembly with multiple components where some components do not have a generator, power can still be provided to the assembly. Additionally, if there are multiple generators, then a better performing generator that generates more electricity can supplement a relatively lower performing generator. For example, if one component is provided with a continuous flow generator, another may be provided with a non-continuous flow generator, meaning that for different use regimes, power generation can be achieved and redundancy is provided. It would be understood that where the valve is a valve assembly with multiple components, the different components may be connected to each other to share power between any two components. For example in all embodiments, the generator 5 is configured to provide power to the valve 3 by means of a cable connection. Alternatively, or additionally, the generator 5 is configured to provide power to the valve 3 by means of inductive or capacitative coupling.

As described above, the generator 5 is configured to provide electrical power both to power a valve but also to charge a battery. Advantageously, the electronic valve may comprise a battery configured to be charged by the generated electricity. It is to be envisioned that the generation of power from the flow 12 of compressible fluid 10 may not be enough for operation of all electronic components on the valve. Thus, the generator 5 may serve as a means to recharge the battery, thus prolonging its period of operation. Furthermore, the battery allows for provision of power to the cylinder even when there is no flow of compressible fluid.

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 . An electronic valve assembly for a cylinder containing a compressible fluid, the valve assembly comprising a generator configured to receive a flow of compressible fluid from the cylinder through the electronic valve assembly to generate electricity, the generated electricity being provided to power the electronic valve assembly or increase the charge stored on a store of charge of the valve assembly.

2. The electronic valve assembly of claim 1 , wherein the generator comprises a flow channel for carrying the flow of compressible fluid and a turbine, the turbine comprising:

an impellor provided in the flow channel and configured such that the flow of the compressible fluid through the flow channel causes a rotation of the impellor; and a magnet connected to the impellor such that rotation of the impellor will induce an electrical current in a coil surrounding the magnet.

3. The electronic valve assembly of claim 2, wherein the magnet is provided in the flow channel.

4. The electronic valve assembly of claim 3, wherein the impellor and the magnet are attached to a shaft axially aligned with the flow channel.

5. The electronic valve assembly of claim 2, wherein the magnet is connected to the impellor by a shaft running through a wall of the flow channel.

6. The electronic valve assembly of claim 1 , wherein the generator comprises a flow channel for carrying the flow of compressible fluid and a moveable element with a first surface and a second surface opposite the first surface,

wherein:

the first surface is in fluid communication with a first portion of the flow channel such that the first surface is at the same pressure as the first portion of the flow channel; andthe second surface is exposed to a pressure defining a reference pressure;

the moveable element is biased towards a first position by a balancing force, whereby a flow of fluid through the flow channel results in a force on the moveable element opposing the balancing force, thereby resulting in a movement of the moveable element, wherein said movement is converted by the generator into electrical current.

7. The electronic valve assembly of claim 6, wherein the generator comprises an urging means connected to the moveable element that is configured to provide the balancing force.

8. The electronic valve assembly of claim 7, wherein the urging means is adjustable to provide an adjustable balancing force.

9. The electronic valve assembly of claim 6, wherein the generator is configured such that the first surface and second surface are arranged vertically opposite when the electronic valve is installed on a cylinder having a vertically aligned longitudinal axis such that the balancing force is a gravitational force.

10. The electronic valve assembly of claim 6, wherein the second surface is in fluid communication with the environment external to the valve, such that the reference pressure is the ambient pressure of the external environment.

1 1 . The electronic valve assembly of claim 6, wherein the second surface is in fluid communication with a second portion of the flow channel such that the reference pressure is a second fluid pressure, wherein the flow channel is shaped such that the second fluid pressure is different to the first fluid pressure.

12. The electronic valve assembly of claim 1 1 , wherein the second portion of the flow channel has a different cross sectional area to the first portion of the flow channel, such that a flow of compressible fluid from the first portion to the second portion results in the difference between the first fluid pressure and the second fluid pressure.

13. The electronic valve assembly of any one of claims 6 to 12, wherein the moveable element forms a fluid impermeable barrier between the flow channel and a variable volume chamber.

14. The electronic valve assembly of any of claims 6 to 13, wherein the moveable element is a diaphragm or a piston.

15. The electronic valve assembly of claim 1 1 , wherein the generator is configured such that a movement of the moveable element adjusts a dimension of a flow channel interface, being an interface between the first portion of the flow channel and the second portion of the flow channel, such that a movement of the moveable element controls the flow between the first portion of the flow channel and the second portion of the flow channel.

16. The electronic valve assembly of claim 15, wherein the generator comprises the flow channel interface such that a flow of compressible fluid through the flow channel includes a flow of the compressible fluid through the generator.

17. The electronic valve assembly of claims 15 or 16, wherein the moveable element comprises a secondary channel and the generator is configured such that a flow of the compressible fluid through the flow channel includes a flow of the compressible fluid through the moveable element.

18. The electronic valve assembly of any preceding claim, wherein the valve is a shut-off valve.

19. The electronic valve assembly of any of claims 1 - 18, comprising an electronic shut-off valve and a secondary valve attached to the shut-off valve.

20. The electronic valve assembly of claim 19, wherein the secondary valve comprises the generator and the generated electricity is provided from the secondary valve to the electronic shut-off valve to power the electronic shut-off valve.

21 . The electronic valve assembly of any preceding claim, wherein the generator provides power to the electronic valve by means of a cable connection.

22. The electronic valve assembly of any preceding claim, wherein the generator provides power to the electronic valve by means of inductive or capacitative coupling.

23. The electronic valve assembly of any preceding claim, further comprising a battery or a capacitor configured to be charged by the electricity generated by the generator.

24. The electronic valve assembly of any preceding claim, further comprising a unitary housing that encloses the valve and the generator.

25. The electronic valve assembly of any preceding claim, wherein the generator forms a pressure regulator of the valve assembly for regulating the pressure of the flow of compressible fluid from the cylinder.

26. An electronic valve assembly substantially as herein described with reference to Figures 1 , 2A, 2B, 2C, 2D, 3, 4, 5A and 5B of the accompanying drawings.