WO2018035517A1

WO2018035517A1 - Gas transfer apparatus

Info

Publication number: WO2018035517A1
Application number: PCT/US2017/047768
Authority: WO
Inventors: Garry HENDERSON; Graham VIOLETT
Original assignee: Kellogg Brown & Root Llc
Priority date: 2016-08-19
Filing date: 2017-08-21
Publication date: 2018-02-22

Abstract

Provided is a gas transfer apparatus for the transfer of one or more gases into and/or out of a liquid including a frame, a gas-penneable membrane disposed on the frame so as to define a gaseous chamber therein and a vibratory element connected to the frame and adapted to produce vibrations that promote the transfer of gases across the membrane. A method for transferring one or more gases between a gaseous chamber and a liquid and a system for cultivating aquatic microorganisms through use of the gas transfer apparatus are also provided.

Description

TITLE

GAS TRANSFER APPARATUS FIELD

The present application claims priority to Australian Provisional Patent

Application Serial No. 2016903297 filed August 19, 2016, the contents of which are incorporated herein by reference. This invention relates to a gas transfer apparatus and method of using same. BACKGROUND

Gas transfer into a liquid phase is well-documented to be constrained by the thickness of the boundary layers on both the gas and liquid sides of the interface. Others have conducted work on the use of gas permeable membranes as a method of transferring gas into and/or out of a liquid. This work has generally demonstrated the liquid side boundary layer as being the limiting step in this process. To this end, some have reported that liquid side velocities need to be in the order of 5 metres per second (m/s) or higher in order to achieve a sufficient reduction in the liquid boundary layer for the method of transfer to be successful. Achieving a flow velocity of 5 m/s in the liquid phase for very large volumes of water typically represents a very high energy requirement and hence may negate the benefits of such a flow velocity in large scale applications, such as aquatic microorganism growth systems.

Therefore, an alternative or improved gas transfer apparatus for transferring one or more gases into and/or out of a liquid is required. SUMMARY

The present invention is broadly directed to a gas transfer apparatus. The invention is further directed to a method of transferring a gas into and/or out of a liquid, that includes use of the gas transfer apparatus described herein.

In a first aspect there is provided a gas transfer apparatus for the transfer of one or more gases into and/or out of a liquid comprising:

a frame;

a gas-permeable membrane disposed on the frame so as to define a gaseous chamber therein; and a vibratory element connected to the frame and adapted to produce vibrations that promote the transfer of gases across the membrane.

Suitably, the vibratory element comprises an electromagnetic element and a vibratory portion disposed in spaced relation to each other, the vibratory portion operably attached to the frame and/or the membrane. Preferably, the vibratoiy element comprises a single electromagnetic element attached to a first side of the frame and the vibratory portion is attached to: (i) a second side of the frame; and/or (ii) a portion of the membrane disposed on the second side of the frame. In particular embodiments, the vibratory portion is selected from the group consisting of a magnet, a pole piece, a further electromagnetic element and any combination thereof.

In an alternative embodiment, the vibratory element comprises a piezoelectric element adjacent the frame and/or the membrane.

In one embodiment, the membrane comprises first and second portions, said portions each having upper and lower ends connected to the frame by respective upper and lower flexible supports.

In particular embodiments, the gas transfer apparatus of the present aspect further comprises a diaphragm mounted within the gaseous chamber, the diaphragm capable of being vibrated by the vibratory element so as to facilitate the production of sound waves therefrom..

In one embodiment, the vibratory element comprises one or more electromagnetic elements and a vibratory portion disposed in spaced relation to each other, the vibratory portion mounted in or on the diaphragm. Preferably, the vibratory element comprises a pair of electromagnetic elements and the vibratory portion is disposed substantially therebetween. In particular embodiments, the vibratory portion is selected from the group consisting of a magnet, a pole piece, a further electromagnetic element and any combination thereof.

In an alternative embodiment, the vibratory element comprises one or more piezoelectric elements adjacent the diaphragm.

In one embodiment, the diaphragm comprises a substantially flat sheet of material. Alternatively, the diaphragm may be substantially elliptically-shaped in cross-section.

In one embodiment, upper and lower ends of the diaphragm are connected to the frame by respective upper and lower flexible supports. In certain embodiments, the sound waves are audible sound waves. In other embodiments, the sound waves are ultrasonic sound waves or infrasonic sound waves. Suitably, vibrating the diaphragm produces sound waves of a frequency in the range of about 10 Hz to about 23000 Hz.

Vibration of the membrane and/or the diaphragm suitably promotes transfer of a first gas from the gaseous chamber therethrough into the liquid.

In a second aspect, the invention provides a method for transferring one or more gases between a gaseous chamber and a liquid, the method including the steps of:

(a) providing a gas transfer apparatus disposed within said liquid, said gas transfer apparatus comprising a frame, a gas-permeable membrane disposed on the frame so as to define the gaseous chamber therein, and a vibratory element connected to the frame;

(b) activating the vibratory element, wherein the vibrations produced therefrom promote transfer of a first gas from the gaseous chamber through the membrane into the liquid.

The gas transfer apparatus is suitably that of the first aspect.

In one embodiment, a second gas is further transferred from the liquid to the gaseous chamber. Accordingly, the method of the present aspect suitably further includes the step of recovering a portion of the second gas from the gaseous chamber.

In one embodiment, the first gas is a sweep gas.

Suitably, the liquid, at least in part, is being used for cultivating an aquatic microorganism therein.

In a third aspect, the invention provides a system for cultivating aquatic microorganisms comprising:

(i) a body of liquid for cultivating said aquatic microorganisms therein; and

(ii) a gas transfer apparatus disposed within the body of liquid, said gas transfer apparatus comprising a frame, a gas-permeable membrane disposed on the frame so as to define a gaseous chamber therein, and a vibratory element connected to the frame;

wherein activation of the vibratory element produces vibrations that promote transfer of one or more gases suitable for use in cultivating the aquatic microorganisms between the gaseous chamber and the body of liquid.

Suitably, the gas transfer apparatus is that of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

In order that the present invention may be readily understood and put into practical effect, reference will now be made to the accompanying illustrations, wherein like reference numerals are used to refer to like elements.

Figure 1 : is a perspective view of an embodiment of an apparatus of the invention. Figure 2: is a cross-sectional view of the apparatus of Figure 1.

Figure 3: is a perspective view of an embodiment of an apparatus of the invention. Figure 4: is a cross-sectional view of the apparatus of Figure 3.

Figure 5: is a perspective view of an embodiment of an apparatus of the invention. Figure 6: is a cross-sectional view of the apparatus of Figure 5.

DETAILED DESCRIPTION

While it is anticipated that the apparatus of the present invention is particularly suited or adapted for use in gas-liquid mass transfer systems for the production of aquatic microorganisms, the apparatus could also be readily utilised in any gas-liquid mass transfer applications where the transfer of one or more gases into and/or out of a liquid by way of a gas permeable membrane is preferred, such as where gaseous transfer by bubble is to be avoided or where removing a dissolved gas by using a sweep gas is required.

The present invention is predicated, at least in part, on sound waves reducing the thickness of the liquid boundary layer, which is typically considered the rate limiting step in gas-liquid mass transfer systems. It is anticipated that the generation of sound waves within a gaseous chamber or lumen of the apparatus provided herein will allow for much lower velocities to be used in the liquid phase external thereto to achieve comparable gas-liquid mass transfer across a gas permeable membrane to that of similar systems which do not utilise sound waves in this manner.

Without being bound by any theory, there are two mechanisms by which the sound waves generated in this manner may be important. The first is that the action of the gas phase within the pores of the membrane. In this regard, the vibration or oscillation of the gas phase is expected to cause an induced oscillation in the neighbouring or adjacent liquid phase because the pores of the gas permeable membrane are effectively nanotubes at the interface. Secondly, the sound waves will typically induce vibration of the membrane itself thereby transferring energy to the liquid adjacent the pores of the membrane, hence reducing the effective thickness of the liquid boundary layer at the gas-liquid interface. In embodiments wherein the membrane itself is directly vibrated by a vibratory element to generate sound waves at the gas-liquid interface (e.g., apparatus 300), it is anticipated that the sound waves will similarly be transferred to the adjacent liquid phase, thereby reducing the effective size of the liquid boundary layer.

Figures 1 through 6 demonstrate a number of embodiments of a gas transfer apparatus that facilitates the transfer of one or more gases into and/or out of a liquid (not shown) in which said apparatus is disposed.

In referring to Figures 1 and 2, the apparatus 100 includes a frame 1 10 having upper and lower base members 111, 111 ' extending along a longitudinal axis thereof. The frame 1 10 also has a first set of four arcuate ribs 112A-D disposed between the upper and lower base members 1 11, 111 ' on a first side 101 thereof and arranged substantially perpendicular thereto. The first set of arcuate ribs 1 12A-D are arranged equidistant along the frame 1 10 and parallel to each other. It will be noted that the arcuate rib 1 12D is not shown in Figure 1.

Each of the first set of arcuate ribs 112A-D are substantially opposite each of a respective second set of arcuate ribs 113A-D positioned on a second side 102 of the frame 1 10. Accordingly, each of the first set of arcuate ribs 1 12A-D has an opposing arcuate rib 113A-D from the second set thereof (e.g., arcuate rib 112A is substantially opposite arcuate rib 1 13A). Both the first set 112A-D and second set 113A-D of arcuate ribs are secured at an upper and lower end thereof to the upper and lower base members 111, 1 11 ' of the frame 110 respectively. Each of the arcuate ribs 1 12A-D, 113A-D has a respective flange portion 116A-D, 117A-D extending or projecting inwardly therefrom.

The frame 1 10 further includes a first set of elongate ribs 114A-C extending along the first side 101 thereof and substantially perpendicular to the first set of arcuate ribs 112A-D. On the second side 102 of the frame 110 is a second set of elongate ribs 1 15A-C arranged to be substantially opposite the first set of elongate ribs 114A-C. As can be seen from Figures 1 and 2, elongate ribs 114A, 115A are adjacent the base member 1 11 on their respective first 101 and second sides 102 of the frame 110 and engaged thereto. Similarly, elongate ribs 114C and 115C are adjacent and secured to the base member 1 11 '. Elongate rib 114B overlies a central portion of each of the first set of arcuate ribs 1 12A-D, whilst elongate rib 1 15B overlies a central portion of each of the second set of arcuate ribs 1 13A-D. To this end, each of the arcuate ribs 112A-D, 113A-D may comprise channel portions at a proximal, middle and distal end thereof of dimensions suitable for receiving therein the respective elongate ribs 1 14A-C, 115A-C.

Referring to Figures 1 and 2, the gas transfer apparatus 100 includes a curvilinear first membrane 120 overlying the arcuate ribs 1 12A-D and the elongate ribs 1 14A-D on the first side 101 thereof. Additionally, the apparatus 100 comprises a curvilinear second membrane 120' on a second side 102 thereof opposite the first membrane 120 and overlying the arcuate ribs 113A-D and the elongate ribs 1 15A-D. Preferably, the first and second membranes 120, 120' are gas permeable and at least substantially liquid impermeable. With respect to being gas permeable, it would be appreciated that this may include embodiments in which the first and second membranes 120, 120' are selectively permeable to one or more particular gases and impermeable to other gases. The membranes 120, 120' are suitably composed of any material known in the art such as hydrophobic polypropylene membranes or polytetrafluoroethylene (PTFE) membranes of such dimensions and properties so as to afford the qualities of being permeable to gaseous components or components in the vapour phase but not to liquids under operative conditions.

By this arrangement, the first and second membranes 120, 120' define a gaseous chamber 105 therebetween and within the frame 110 which extends the length of the apparatus 100. It will be appreciated that in Figure 1, the second membrane 120' is not shown in its entirety so as to allow for visualisation of the internal structures of the apparatus 100. In particular embodiments, the first and/or second membranes 120, 120' are adapted to be permeable to a first gas and/or a second gas.

The apparatus 100 further includes a first vibratory element 140 and a second vibratory element 150. As can be observed in Figure 1, the vibratory elements 140, 150 each comprise a pair of electromagnetic coils 141A-B, 151A-B, extending between and therearound the flange portions 116A-D, 117A-D of two adjacent arcuate ribs of the first set 1 12A-D or second set 1 13A-D. By virtue of this arrangement, each member of the pair of electromagnetic coils 141 A-B, 151A-B is positioned on opposing sides of the apparatus 100 in relatively close proximity to the other member of said pair. Although not shown in Figures 1 or 2, it would be apparent that the electromagnetic coils 141A^*-B, 151A-B are operably or electrically connected to a power source (not shown) by a respective connector 145A-B, 155A-B. In the embodiment shown, the connectors 145A-B, 155A-B exit the apparatus 100 through an end thereof with appropriate seals as required for the operating environment so as to engage an external power source (not shown). Alternatively, the apparatus 100 may comprise an internal power source. Additionally, it would be understood by the skilled artisan that the present invention could be practiced with a vibratory element of some other type or form, such as a piezoelectric element or transducer. Furthermore, the skilled person would appreciate that the electromagnetic coils 141A- B, 151A-B are not to be limited to any particular form or arrangement and as such need not necessarily comprise coils wound around a flange. Furthermore, the electromagnetic coils 141 A-B, 151 A-B may be of any size and number. In this regard, the electromagnetic coils 141 A-B, 151A-B may comprise a single large electromagnetic coil and/or multiple smaller electromagnetic coils suitably arranged together.

In reference to the embodiment provided in Figures 1 and 2, the apparatus 100 further includes an acoustic diaphragm 130 comprising a thin membrane or sheet of a semi-flexible or rigid material preferably suitable for vibration thereof at audible, infrasonic and/or ultrasonic frequencies. Nonlimiting examples of such materials include paper, paper composites and laminates, polypropylene (PP), polycarbonate (PC), Mylar (PET), silk, glassfibre, carbon fibre, titanium, aluminium, aluminium- magnesium alloy, nickel, and beryllium. The diaphragm 130 is disposed centrally within the frame 110 and extends axially along a longitudinal axis of the apparatus 100 by virtue of being suspended and supported at a proximal and a distal edge thereof to upper and lower flexible supports 1 19, 119' respectively, which are further secured to the base members 11 1, 1 11 ' respectively. In Figure 1, it will be noted that the diaphragm 130 is not shown in its entirety so as to allow for visualisation of the internal structures of the apparatus 100.

Each of the vibratory elements 140, 150 of the apparatus 100 further include a magnet qr a ferrous metal pole piece 142, 152 respectively. In particular embodiments, the magnets 142, 152 are permanent magnets as are known in the art. In alternative embodiments, it would be appreciated that the magnets or pole pieces 142, 152 may be replaced by some other magnetisable material or a further electromagnetic element. Each of the magnets or pole pieces 142, 152 is secured or attached centrally on or within the acoustic diaphragm 130 and disposed between their respective pair of electromagnetic coils 141A-B, 151A-B in a spaced relation thereto. To this end, the magnet or pole piece 142 is disposed centrally between the electromagnetic coils 141A-B and the magnet or pole piece 152 is disposed centrally between the electromagnetic coils 151A-B. It would be appreciated that the electromagnetic coils 141A-B, 151A-B and magnets or pole pieces 142, 152 (i.e., the vibratory elements 140, 150) do not have to be positioned or arranged centrally within the frame 1 10 in order to practice the present invention.

Each pair of electromagnetic coils 141A-B, 151A-B is operable to generate a fluctuating reversing magnetic field that interacts with a static magnetic field produced by their respective magnet or pole piece 142, 152 disposed therebetween on the acoustic diaphragm 130. The magnetic field may be generated by the electromagnetic coils 141A-B, 151 A-B continuously in opposite phase to create a push-pull alternating force on the magnet 142, 152, or alternatively when used with a ferrous metal pole piece 142, 152, the field may be generated alternatively for each electromagnetic coil 141 A-B, 151 A-B, alternating with each change in polarity for each half-wave to respectively attract the pole piece 142, 152 to alternate sides as each electromagnetic coil 141 A-B, 151 A-B alternately generates an electromagnetic field. Accordingly, by means of the electromagnetic coils 141 A-B, 151 A-B when energized, the magnets or pole pieces 142, 152 are moved back and forth at a desired frequency so as to facilitate vibration of the acoustic diaphragm 130. As a result of this vibration of the acoustic diaphragm 130, sound waves are produced therefrom.

The vibratory elements 140, 150 may be manually or automatically controlled or modulated by a control device (not shown). In this regard, the control device is suitably able to not only activate the vibratory elements 140, 150 to drive vibration of the acoustic diaphragm 130, but also adjust the frequency of vibration of the acoustic diaphragm 130, and therefore modify the frequency of sound waves produced therefrom as is required for gas transfer between the gaseous chamber 105 and an adjacent liquid.

The vibratory output or sound waves produced by the vibratory elements 140,

150 may be of an audible frequency, infrasonic frequency or an ultrasonic frequency. An audible frequency is generally characterized as a periodic vibration whose frequency is audible to the average human (e.g., between approximately 20 and 20,000 Hz). It would be appreciated that the term "ultrasonic" applied to sound refers to anything above the frequencies of audible sound, and typically includes frequencies over 20,000 Hz. Frequencies below 20 Hz are generally considered inaudible and are often referred to as sub-bass, infra-bass or infrasonic. For the production of sound waves of ultrasonic frequency, the vibratory elements 140, 150 preferably include a piezoelectric element or transducer.

The sound waves produced by the apparatus 100 described herein may be of about 10 to about 23,000 Hz, or any range therein, such as, but not limited to, about 200 to about 20,000 Hz, or about 500 to about 10,000 Hz. In particular embodiments of the present invention, the sound waves described herein are about 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000, 7500, 8000, 8500, 9000, 9500, 10000, 11000, 12000, 13000, 14000, 15000, 16000, 17000, 18000, 19000, 20000, 21000, 22000, 23000 Hz, or any range therein..

When in use, a first gas for transfer from the apparatus 100 to an adjacent liquid in which the apparatus 100 is submerged or disposed is introduced into the gaseous chamber 105 via a gas inlet (not shown) at a proximal end (not shown) thereof. While passing through the length of the gaseous chamber 105 of the apparatus 100, a portion of the first gas is subjected to transfer through the first and second membranes 120, 120'. This transfer or passage of the first gas through the pores of the first and second membranes 120, 120' into the adjacent liquid is promoted or enhanced by those sound waves produced by the action of the vibratory elements 140, 150 on the diaphragm 130, which are then incident on said membranes 120, 120' to elicit vibration thereof.

In addition to transfer of the first gas, there may also be an exchange of further gaseous components through the first and second membranes 120, 120', such that, for example, a second gas may be transferred from the liquid through the membranes 120, 120' and received into the gaseous chamber 105. Once received into the apparatus 100, the second gas may then be transported the length of the gaseous chamber 105 to be finally discharged therefrom at a gas outlet (not shown). It would be appreciated that the second gas and other such gases removed from the adjacent liquid may be useful and/or valuable, such as for the growth of aquatic microorganisms. Accordingly, the second gas may be captured and recovered for other downstream uses as required. Figures 3 and 4 illustrate a further embodiment of a gas transfer apparatus 200, which is similar to that of gas transfer apparatus 100. In this regard, the gas transfer apparatus 200 includes a frame 210 having upper and lower base members 211, 211 ' defining a longitudinal axis thereof and a first and second set of arcuate ribs 212A-D, 213A-D mounted therebetween on respective first and second sides 201, 202 of the frame 210 and arranged similarly to that of gas transfer apparatus 100 (i.e., spaced equidistant along the frame 210 and substantially parallel to each other, whilst being substantially perpendicular to the base members 21 1, 21 ). As such, each of the first set of arcuate ribs 212A-D has an opposing arcuate rib 213A-D from the second set thereof in spaced relation to each other. Further, each of the arcuate ribs 212A-D, 213A-D has a respective flange portion 216A-D, 217A-D extending or projecting inwardly therefrom.

The frame 210 further includes a first and second set of elongate ribs 214A-C, 215A-C extending axially along the longitudinal axis of the gas transfer apparatus 200 on the respective first and second sides 201, 202 thereof. As can be observed from Figures 3 and 4, the elongate ribs 214A-C, 215A-C are similarly arranged to that of the aforementioned gas transfer apparatus 100. In this regard, elongate ribs 214A, 214C, 215A, 215C are mounted adjacent their respective base member 211, 21 Γ on the first and second sides 201, 202 respectively of the frame 210. Further, elongate ribs 214B, 215B overlie a central portion of their respective arcuate ribs 212A-D, 213A-D and suitably reside in channel portions therein.

In reference to Figures 3 and 4, the gas transfer apparatus 200 includes curvilinear first and second membranes 220, 220' overlying their respective arcuate ribs 212A-D, 213A-D and elongate ribs 214A-D, 215A-d on respective first and second sides 201, 202 of the frame 210. Preferably, the first and second membranes 220, 220' are gas permeable and at least substantially liquid impermeable and suitably comprise any material known in the art, such as those described herein. Similarly for the gas transfer apparatus 100, the first and second membranes 220, 220' define a gaseous chamber 205 therebetween and within the frame 210, which extends the length of the gas transfer apparatus 200. It will be noted from Figure 3 that the second membrane 220' is not shown in its entirety. Suitably, the first and/or second membranes 220, 220' are adapted to be permeable to one or more gases, such as a first gas and/or a second gas as hereinbefore described. The apparatus 200 further includes a first vibratory element 240 and a second vibratory element 250 spaced equidistant therealong. As can be observed in Figure 3, the vibratoiy elements 240, 250 each comprise a pair of electromagnetic coils 241A- B, 251 A-B, extending between and therearound the flange portions 216A-D, 217A-D of two adjacent arcuate ribs of the first set 212A-D or second set 213A-D. As a result of this arrangement, each member of the pair of electromagnetic coils 241 A-B, 251A- B is positioned on opposing sides of the apparatus 200 in a relatively close spaced relationship to the other member of said pair. The electromagnetic coils 241 A-B, 251 A-B are operably or electrically connected to a power source (not shown) by a respective connector 245A-B, 255A-B. In the embodiment shown, the connectors 245A-B, 255A-B exit the apparatus 200 through the membranes 220, 220' so as to engage an external power source (not shown). Alternatively, the apparatus 200 may comprise an internal power source. Additionally, it would be apparent that the present invention could be practiced with a vibratory element of some other type or form, such as a piezoelectric element or transducer.

In reference to the embodiment provided in Figures 3 and 4, the apparatus 200 further includes an acoustic diaphragm 230 which is elliptically-shaped in cross- section. To this end, the cross-sectional shape of the diaphragm 230 has been contoured to match the cross-sectional shape of the apparatus 200 formed by the membranes 220, 220' so as to optimise radiation or distribution of the sound waves produced therefrom outwards. It would be appreciated that the diaphragm 230 may comprise an alternative cross-sectional shape that similarly optimises the radiation or distribution of the sound waves produced therefrom. The diaphragm 230 comprises a semi-flexible or rigid material, such as those previously described herein, preferably suitable or configured for vibration thereof at audible, infrasonic and/or ultrasonic frequencies. The diaphragm 230 is disposed centrally within the gaseous chamber 205 of the frame 210 and extends axially therealong. To this end, the diaphragm 230 is suspended and supported at a proximal and a distal edge thereof to upper and lower flexible supports 219, 219' respectively, which are further secured to the base members 21 1, 211' respectively. It will be noted that in Figure 3 the diaphragm 230 is not shown in its entirety.

Each of the vibratory elements 240, 250 of the apparatus 200 further include a pair of permanent magnets or pole pieces 242, 242', 252, 252' respectively (magnets/pole pieces 252, 252' are not shown in Figure 3), mounted within the acoustic diaphragm 230 and disposed between their respective pair of electromagnetic coils 241A-B, 251 A-B. To this end, the magnets or pole pieces 242, 242' are disposed centrally in a spaced relation between the electromagnetic coils 241A-B and the magnets or pole pieces 252, 252' are disposed centrally in a spaced relation between the electromagnetic coils 251 A-B. It would be appreciated that the vibratory elements 240, 250 do not have to be positioned or arranged centrally within the frame 210 in order to practice the present invention.

The vibratory elements 240, 250 operate similarly to those of the gas transfer apparatus 100. To this end, each pair of electromagnetic coils 241A-B, 251A-B is operable to generate a magnetic field that fluctuates back, and forth and interacts with the magnetic field of either of the permanent magnets or the pole pieces 242, 242', 252, 252' disposed therebetween on the acoustic diaphragm 230. Accordingly, by means of the electromagnetic coils 241 A-B, 251 A-B when energized, the magnets or pole pieces 242, 242', 252, 252' are moved back and forth at a desired frequency so as to facilitate vibration of the acoustic diaphragm 230. Additionally, the vibratory elements 240, 250 may be manually or automatically controlled or modulated as previously described herein. Suitably, the sound waves produced by vibration of the diaphragm 230 are of an audible, infrasonic frequency or an ultrasonic frequency as hereinbefore described.

When in use, a first gas for transfer from the apparatus 200 to an adjacent liquid in which the apparatus 200 is submerged or disposed is introduced into the gaseous chamber 205 via a gas inlet (not shown) at a proximal end (not shown) thereof. While passing through the length of the gaseous chamber 205 of the apparatus 200, a portion of the first gas is subjected to transfer through the first and second membranes 220, 220'. This transfer or passage of the first gas through the pores of the first and second membranes 220, 220' into the adjacent liquid is promoted or enhanced by those sound waves produced by the action of the vibratory elements 240, 250 on the diaphragm 230. In addition to transfer of the first gas, there may also be an exchange of gaseous components through the first and second membranes 220, 220', such that, for example, a second gas may be transferred from the liquid through the membranes 220, 220' and received into the gaseous chamber 205. Once received into the apparatus 200, the second gas may then be transported the length of the gaseous chamber 205 to be finally discharged therefrom at a gas outlet (not shown). Suitably, the second gas is captured and recovered for other downstream uses as required.

Figures 5 and 6 illustrate a further embodiment of a gas transfer apparatus 300. The gas transfer apparatus 300 includes a frame 310 having upper and lower base members 31 1, 311 ' defining a longitudinal axis thereof and a first and second set of arcuate ribs 312A-D, 313A-D disposed therebetween on respective first and second sides 301, 302 of the frame 310. The arcuate ribs 312A-D, 313A-D are suspended and secured at a proximal and a distal edge thereof to upper and lower flexible supports 319A-B, 319'A-B respectively, which are further secured to the base members 311, 31 1 ' respectively. The arcuate ribs 312A-D, 313A-D are arranged so as to be spaced equidistant along the frame 310 and substantially parallel to each other, whilst being substantially perpendicular to the base members 311, 31 Γ. Each of the first set of arcuate ribs 312A-D has an opposing arcuate rib 313A-D from the second set thereof in spaced relation to each other. Each of the arcuate ribs 312A-D, 313A-D has a respective flange portion 316A-D, 317A-D extending or projecting inwardly therefrom.

The frame 310 further includes a first and second set of elongate ribs 314A-C, 315A-C extending axially along the longitudinal axis of the gas transfer apparatus 300 on the respective first and second sides 301, 302 thereof. The elongate ribs 314A, 314C, 315A, 315C are mounted adjacent their respective flexible support 319A, 319Ά, 319B, 319'B on the first and second sides 301, 302 respectively of the frame 310. Further, elongate ribs 314B, 315B overlie a central portion of their respective arcuate ribs 312A-D, 313A-D and may reside in suitably dimensioned channel portions therein.

In reference to Figures 5 and 6, the gas transfer apparatus 300 includes curvilinear first and second membranes 320, 320' overlying their respective arcuate ribs 312A-D, 313A-D and elongate ribs 314A-D, 315A-D on respective first and second sides 301, 302 of the frame 310. Preferably, the first and second membranes 320, 320' are gas permeable and at least substantially liquid impermeable and comprise any suitable material known in the art, such as those described herein. The first and second membranes 320, 320' together with the frame 310 define a gaseous chamber 305 therebetween, which extends the length of the gas transfer apparatus 300. It will be noted from Figure 5 that the second membrane 320' is not shown in its entirely. Suitably, the first and/or second membranes 320, 320' are adapted to be permeable to one or more gases, such as a first gas and/or a second gas as hereinbefore described.

The apparatus 300 further includes a first vibratory element 340 and a second vibratory element 350 spaced equidistant therealong. As can be observed in Figure 3, the vibratory elements 340, 350 each comprise a single electromagnetic coil 341, 351 extending between and therearound the flange portions 316A-B, 316C-D respectively on the first side 301 of the frame 310. The electromagnetic coils 341 , 351 are operably or electrically connected to a power source (not shown) by a respective connector 345, 355. In the embodiment shown, the connectors 345, 355 exit the apparatus 300 through the membrane 320 so as to engage an external power source (not shown). Alternatively, the apparatus 300 may comprise an internal power source. Additionally, it would be apparent that the present invention could be practiced with a vibratory element of some other type or form, such as a piezoelectric element or transducer.

Each of the vibratory elements 340, 350 further include a permanent magnet or a magnetized pole piece 342, 352 respectively (magnet 342 is not shown in Figure 3), mounted within flange portions 317A-B, 317C-D so as to be positioned immediately opposite and in spaced relation to their respective electromagnetic coils 341, 351. It would be appreciated that the vibratory elements 340, 350 do not have to be positioned or arranged centrally within the frame 310 in order to practice the present invention. Further, the electromagnetic coils 341, 351 may be positioned the second side of the frame 302, such as in an alternating fashion. Additionally, one or more of the magnets or pole pieces 342, 352 may be positioned or mounted elsewhere in the frame. The magnets or pole pieces 342, 352 may also or alternatively be mounted adjacent the first and/or second membranes 320, 320'.

Further, it would be appreciated by the skilled artisan that the vibratory elements 340, 350 need not be disposed within the gaseous chamber 305. In alternative embodiments, one or both of the vibratory elements 340, 350, or at least certain components thereof (e.g., one or both of the magnets or pole pieces 342, 352) are external to the gaseous chamber 305. By way of example, one or more piezoelectric elements may be mounted on an external surface of one or both of the membranes 320, 320'.

Functionally, each electromagnetic coil 341, 351 is operable to generate a magnetic field that fluctuates back and forth against a static magnetic field produced by their respective opposing magnet or pole piece 342, 352 mounted on the frame 310. Accordingly, by means of the electromagnetic coils 341, 351 when energized, the magnets or pole pieces 342, 352 are moved back and forth at a desired frequency so as to elicit vibration of the frame 310, which in turn induces vibration of the membranes 320, 320' disposed thereon. Accordingly, both the frame 310 and the membranes 320, 320' may produce sound waves as a result of this vibration thereof, which are suitably of an audible frequency or an ultrasonic frequency as hereinbefore described. Additionally, the vibratory elements 340, 350 may be manually or automatically controlled or modulated as previously described herein.

When in use, a first gas for transfer from the apparatus 300 to an adjacent liquid in which the apparatus 300 is submerged or disposed is introduced into the gaseous chamber 305 via a gas inlet (not shown) at a proximal end (not shown) thereof. While passing through the length of the gaseous chamber 305 of the apparatus 300, a portion of the first gas is subjected to transfer through the first and second membranes 320, 320'. This transfer or passage of the first gas through the pores of the first and second membranes 320, 320' into the adjacent liquid is promoted or enhanced by those sound waves produced by the action of the vibratory elements 340, 350 on the membranes 320, 320' to elicit vibration thereof. Accordingly, the vibratory elements 340, 350 of the apparatus 300 may be considered to directly vibrate the membranes 320, 320' or indirectly vibrate the membranes 320, 320' by way of the frame 310.

In addition to transfer of the first gas, there may also be an exchange of further gaseous components through the first and second membranes 320, 320', such that, for example, a second gas may be transferred from the liquid through the membranes 320, 320' and received into the gaseous chamber 305. Once received into the apparatus 300, the second gas may then be transported the length of the gaseous chamber 305 to be finally discharged therefrom at a gas outlet (not shown). Suitably, the second gas is captured and recovered for other downstream uses as required.

It would be appreciated that for the embodiments provided herein the gas transfer apparatus may be of any length, shape or diameter so as to be suitable for use in a particular body of liquid as required by a user. By way of example, the cross- sectional shape of the gas transfer apparatus described herein may be circular, square or rectangular rather than elliptical. As such, the membranes (e.g., membranes 120, 120', 220, 220', 320, 320') defining the gaseous chamber (e.g., gaseous chambers 105, 205, 305) may be substantially flat or planar rather than curvilinear as previously described herein. Additionally, the above described apparatus may also include any desired number of vibratory elements in any particular arrangement so as to effectively promote the transfer and/or exchange of one or more gases therein.

In aquatic microorganism growth systems, one or more gases, and particularly those used in respect of the growth of said microorganism, are typically valuable and it is preferable to capture and recover such gases rather than lose quantities of these gases to the atmosphere, such as occurs with bubble systems. Accordingly, in particular embodiments, the apparatus 100, 200, 300 described herein is for use in the transfer of a first gas into and/or a second gas out of a liquid that is being used, at least in part, for the growth of microorganisms. In this regard, the first gas for transfer into the liquid may function as a sweep gas to remove the second gas dissolved in said liquid, the second gas suitable being a by-product of microbial growth therein.

To this end, the sweep gas may be the same gas as the second gas, or more preferably the sweep gas may be different. For example, the sweep gas may be air to remove dissolved C0₂. Or the sweep gas may be compressed C0₂ (for example) to remove dissolved C0₂. The sweep gas may be introduced into the apparatus of the present invention at high velocities to facilitate removal of the second gas upon transfer into the apparatus of the invention and thereby preventing or inhibiting the second gas re-dissolving into the adjacent liquid.

By way of example, in embodiments wherein a liquid is being used to cultivate or culture a photosynthetic microorganism (e.g., microalgae and cyanobacteria), the first gas is or comprises carbon dioxide (C0₂) which is transferred out of the gaseous chamber of the apparatus into said liquid to then act as a sweep gas to remove a portion of the oxygen (0₂) dissolved therein, which is then transferred, at least in part, into the gaseous chamber. The 0₂ captured within the gaseous chamber may then be recovered and subsequently used to grow a heterotrophic microorganism.

In an alternative embodiment wherein a liquid is being used to cultivate or culture a heterotrophic microorganism (e.g., yeasts, moulds and bacteria), the first gas is or comprises atmospheric air or 0₂, which is transferred out of the gaseous chamber of the apparatus into said liquid to then act as a sweep gas to remove a portion of the C0₂ dissolved therein, which is then transferred, at least in part, into the gaseous chamber. The C0₂ captured within the gaseous chamber may then be recovered and subsequently used to grow a photosynthetic microorganism. As used herein, the term "cultivated," and variants thereof, refer to the intentional fostering of growth (i.e., increases in cell size, cellular contents, and/or cellular activity) and/or propagation (i.e., increases in cell numbers via mitosis) of one or more cells by the application of intended culture conditions. The one or more cells may be those of an aquatic microorganism, including heterotrophic and photosynthetic microorganisms.

In this specification, adjectives such as first and second, and the like may be used solely to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order. Words such as "comprises" or "includes" are intended to define a non-exclusive inclusion, such that a method or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed, including elements that are inherent to such a method or apparatus.

It will be appreciated that the indefinite articles "a" and "an" are not to be read as singular indefinite articles or as otherwise excluding more than one or more than a single subject to which the indefinite article refers. For example, "a" magnet includes one magnet, one or more magnets and a plurality of magnets.

Throughout the specification the aim has been to describe the preferred embodiments of the invention without limiting the invention to any one embodiment or specific collection of features. It will therefore be appreciated by those of skill in the art that, in light of the instant disclosure, various modifications and changes can be made in the particular embodiments exemplified without departing from the scope of the present invention.

All computer programs, algorithms, patent and scientific literature referred to herein is incorporated herein by reference.

Claims

1. A gas transfer apparatus for the transfer of one or more gases into and/or out of a liquid comprising:

a frame;

a gas-penneable membrane disposed on the frame so as to define a gaseous chamber therein; and

a vibratory element connected to the frame and adapted to produce vibrations that promote the transfer of gases across the membrane.

2. The gas transfer apparatus of Claim 1, wherein the vibratory element comprises an electromagnetic element and a vibratory portion disposed in spaced relation to each other, the vibratory portion operably attached to the frame and/or the membrane.

3. The gas transfer apparatus of Claim 2, wherein the vibratory element comprises a single electromagnetic element attached to a first side of the frame and the vibratoiy portion is attached to: (i) a second side of the frame; and/or (ii) a portion of the membrane disposed on the second side of the frame.

4. The gas transfer apparatus of Claim 2, wherein the vibratory portion is selected from the group consisting of a magnet, a pole piece, a further electromagnetic element or any combination thereof.

5. The gas transfer apparatus of Claim 3, wherein the vibratory portion is selected from the group consisting of a magnet, a pole piece, a further electromagnetic element or any combination thereof.

6. The gas transfer apparatus of Claim 1, wherein the vibratory element comprises a piezoelectric element adjacent the frame and/or the membrane.

7. The gas transfer apparatus of Claim 1, wherein the membrane comprises first and second portions, said portions each having upper and lower ends connected to the frame by respective upper and lower flexible supports.

8. The gas transfer apparatus of Claim 2, wherein the membrane comprises first and second portions, said portions each having upper and lower ends connected to the frame by respective upper and lower flexible supports.

9. The gas transfer apparatus of Claim 1, further comprising a diaphragm mounted within the gaseous chamber, the diaphragm capable of being vibrated by the vibratory element so as to facilitate the production of sound waves therefrom.

10. The gas transfer apparatus of Claim 9, wherein the vibratory element comprises one or more electromagnetic elements and a vibratory portion disposed in spaced relation to each other, the vibratory portion mounted in or on the diaphragm.

1 1. The gas transfer apparatus of Claim 10, wherein the vibratory element comprises a pair of electromagnetic elements and the vibratory portion is disposed substantially therebetween.

12. The gas transfer apparatus of Claim 10, wherein the vibratory portion is selected from the group consisting of a magnet, a pole piece, a further electromagnetic element or any combination thereof.

13. The gas transfer apparatus of Claim 11, wherein the vibratory portion is selected from the group consisting of a magnet, a pole piece, a further electromagnetic element or any combination thereof.

14. The gas transfer apparatus of Claim 1, wherein the vibratory element comprises a piezoelectric element adjacent the diaphragm.

15. The gas transfer apparatus of Claim 9, wherein the diaphragm comprises a substantially flat sheet of material.

16. The gas transfer apparatus of Claim 9, wherein the diaphragm comprises a substantially flat sheet of material.

17. The gas transfer apparatus of Claim 9, wherein the diaphragm comprises a substantially flat sheet of material.

18. The gas transfer apparatus of Claim 9, wherein the diaphragm comprises a substantially flat sheet of material.

19. The gas transfer apparatus of Claim 9, wherein the diaphragm is substantially elliptically-shaped in cross-section

20. The gas transfer apparatus of Claim 9, wherein upper and lower ends of the diaphragm are connected to the frame by respective upper and lower flexible supports.

21. The gas transfer apparatus of 9, wherein the sound waves are audible sound waves.

22. The gas transfer apparatus of Claim 9, wherein the sound waves are ultrasonic or infrasonic sound waves.

23. The gas transfer apparatus of Claim 9, wherein vibrating the diaphragm produces sound waves of a frequency in the range of about 10 Hz to about 23,000 Hz.

24. The gas transfer apparatus of Claim 9, wherein the vibrations produced by the vibratory element promote transfer of a first gas from the gaseous chamber therethrough into the liquid.

25. A method for transferring one or more gases between a gaseous chamber and a liquid, the method including the steps of:

26. The method of Claim 25, wherein the gas transfer apparatus is that of Claim 1.

27. The method of Claim 25, wherein a second gas is further transferred from the liquid to the gaseous chamber.

28. The method of Claim 25, further including the step of recovering a portion of the second gas from the gaseous chamber.

29. The method of Claim 25, wherein the first gas is a sweep gas.

30. The method of Claim 25, wherein the liquid, at least in part, is being used for cultivating an aquatic microorganism therein.

31. A system for cultivating aquatic microorganisms comprising:

(i) a body of liquid for cultivating said aquatic microorganisms therein; and

32. The system of Claim 31 , wherein the gas transfer apparatus is that of Claim 1.