TECHNICAL FIELD

The present disclosure relates generally to liquid processing systems that diffuse, when in operation, a gas into a flow of a liquid, for example liquid processing systems that diffuse carbon dioxide into a flow of a beverage such as a beer, wine or ale. Moreover, the present disclosure also relates to method of (for) carbonating a flow of a liquid using the aforementioned systems. Furthermore, the present disclosure also relates to a pressure control device that operates in the aforementioned systems to provide a temporal pressure control that is capable of preventing pressure transients from adversely affecting operation of the aforementioned systems (for example, where the systems employ long lengths (for example, longer than 50 metres) of piping for delivering fluids for consumption).

BACKGROUND

During brewing of many types of beverages, for example beers, yeast is added to a brewing mixture that results in the beverages being brewed to become carbonated. Such a carbonation results in a well-known "head" or "foam" formed at an upper surface of a given quantity of beverage when dispensed in a glass, "jar" or mug for consumption. The "head" or "foam" is aesthetically a prized characteristic by consumers and is regarded as a quality-distinguishing feature of the given dispensed quantity of beverage. The "head" or "foam" arises because agitation of the given quantity of beverage causes viscous warming of the beverage, and the beverage experiences a pressure reduction when dispensed into the glass, "jar" or mug, resulting in Carbon Dioxide gas coming out of solution.

Often, beverages are provided to customers in glass bottles, wherein the glass bottles are able to withstand a pressure increase arising therein as a result of carbon dioxide coming out of solution from beverage included within the bottles. However, it is more convenient to transport large quantities of beverage from a manufacturing plant (i.e. a brewery) to a beverage dispensing location, for example in a large container (for example, in drums or kegs) to a public house (colloquial : "pub") or a bar, in an un-carbonated state. A disadvantage of transporting large quantities of un-carbonated beverage is that apparatus for carbonating the un-carbonated beverage has to be provided at a location where the beverage is to be dispensed to customers, wherein the customers have an expectation of consuming a carbonate beverage provided with a characteristic "head" or "foam" on an upper surface of the beverage. The present disclosure is concerned with the aforesaid apparatus for providing gas diffusion in flows of liquids, for example for carbonating a flow of a beverage.

Apparatus for on-site carbonating beverages are known. For example, an older US granted patent US 2, 017, 879 (Wiechmann, " Apparatus for carbonating beer or other beverages ") discloses a system including, in combination, a beer barrel, a tube extending thereinto, a source of Carbon Dioxide under pressure, means connected to the source for delivering a small but substantially constant stream of Carbon Dioxide to the beer following withdrawal of the beer beneath its surface through the tube so as to keep the beer carbonated and to build up a pressure on the surface of the beer sufficient for slow withdrawals thereof, and means connected to the source for supplying Carbon Dioxide to the surface of the beer much more rapidly for rapid withdrawal thereof. In a recently published United States patent application US2014/363548 A1 (" Apparatus and Method for Customizing a Beverage's Carbonation Lever, Applicant: Cornelius Inc.), there is disclosed a method for (of) creating a customized carbonated beverage, wherein the method comprises steps of: receiving a user-selected carbonation level; using a computer processing unit (CPU) to open an inlet valve, where the inlet valve is connected between a pressurized Carbon Dioxide supply and a mixing vessel; monitoring the pressure level in the mixing vessel; sending a signal representative of a Carbon Dioxide pressure level in the mixing vessel from a pressure sensor to the CPU; closing the inlet valve when a first predetermined pressure level is achieved; activating a motor to agitate the mixing vessel; opening the inlet valve when a second, lower predetermined pressure level is achieved; and using a timer to measure the time between the first predetermined pressure level and the second predetermined pressure level. When performing on-site carbonation of liquids, for example beverages, reliability of carbonation apparatus employed is very important. Moreover, there is a requirement that the apparatus should be easy to maintain and repair. Furthermore, in compact public houses and bars, there is also a requirement that carbonation apparatus should be spatially compact. Such requirements are not comprehensively addressed by known types of carbonation apparatus, for example as described in the foregoing, that represents a technical problem that the present disclosure seeks to provide a solution.

SUMMARY The present disclosure seeks to provide an improved liquid processing system that that more effectively and reliably diffuses, when in operation, a gas into a flow of a liquid, for example to carbonate a flow of a beverage.

Moreover, the present disclosure seeks to provide an improved pressure control device for use in the aforesaid improved liquid processing system.

Furthermore, the present disclosure also seeks to provide an improved method of (for) operating the aforementioned liquid processing system.

According to a first aspect, there is provided a liquid processing system that diffuses, when in operation, a gas into a flow of a liquid, wherein the system comprises:

(i) a diffusion chamber through which the flow of the liquid occurs, the diffusion chamber including a gas exchange membrane arrangement in fluidic communication with the flow of the liquid;

(ii) a gas reservoir that is coupled via a gas inlet port of a gas plenum to the gas exchange membrane arrangement to supply gas, in operation, to the flow of the liquid;

(iii) a liquid container that is coupled to the diffusion chamber via a liquid inlet port to supply, in operation, the flow of the liquid, and characterised in that (iv) the liquid processing system includes a pressure control device between the gas reservoir and the gas inlet port, wherein the pressure control device includes first and second gas flow paths therethrough arranged fluidically in parallel, wherein the first gas flow path operates to limit a pressure drop thereacross to a maximum pressure drop and the second gas flow path is a bleed flow path having a resistance to gas flow therethrough; wherein the pressure control device functions to maintain a pressure of gas within the gas plenum lower than a pressure of the flow of the liquid at temporal commencement and cessation of the flow of the liquid through the diffusion chamber, wherein the pressure of the flow of liquid above the pressure of gas within the gas plenum is limited within a maximum differential pressure.

The present invention is of advantage in that the pressure control device provides a practical and cost-effective control of pressure transients that arise in the liquid processing apparatus, wherein the pressure transients would otherwise potentially cause sub-optimal reliability of the liquid processing apparatus.

Optionally, the maximum differential pressure is in a range of 3 Psi (20.684 kPa) to 10 Psi (68.948 kPa); "Psi" is an abbreviation for "pounds per square inch" and "kPa" is an abbreviation of "kiloPasca I" (namely an SI unit).

Optionally, the pressure control device is implemented such that:

- the first gas flow path includes a pressure plate that is maintained by a spring force against an orifice seal, the spring force being generated by a spring arrangement, wherein the maximum pressure drop occurs when a force exerted due to pressure of gas on the pressure plate exceeds the spring force.

Optionally, the second gas flow path is provided as a channel in a sealing "0"-ring of the orifice seal and/or as a gas bleed hole arrangement provided on the pressure plate. The gas bleed hole, for example, has a diameter in a range of 0.25 mm to 5.0 mm, more optionally in a range of 0.5 mm to 2.0 mm; the channel in the "0"-ring is mutatis mutandis similarly sized. Optionally, the gas is Carbon Dioxide (CO2) gas.

Optionally, the gas exchange membrane arrangement comprises a plurality of elongate capillary tubes arranged with their elongate axes disposed along an elongate axis of the diffusion chamber, wherein each of the plurality of elongate capillary tubes comprises a membrane that, when in operation, diffuses the gas flowing through the elongate capillary tube arrangement into the flow of the liquid flowing through the diffusion chamber.

Optionally, the liquid processing system further comprises a pump that, when in operation, pumps or otherwise forces a flow of the liquid from the liquid container into the diffusion chamber. More optionally, the liquid processing system further comprises an outlet port arranged on the diffusion chamber that guides a flow of the liquid comprising the diffused from the diffusion chamber.

Optionally, the liquid processing system further comprises a dispensing valve arranged with the outlet port, wherein the dispensing valve controls, in operation, the flow of the liquid having the diffused gas from the diffusion chamber.

Optionally, the liquid having the diffused gas is a carbonated beverage.

Optionally, the diffusion chamber has a cylindrical structure, wherein the cylindrical structure has an elongate height in a range of 150 millimetres to 400 millimetres and a diameter in a range of 30 millimetres to 120 millimetres. Optionally, the plurality of elongate capillary tubes has a length in a range of 100 millimetres to 300 millimetres, more optionally in a range of 180 millimetres to 220 millimetres, and an external diameter in a range of 0.5 millimetres to 1.5 millimetres. Optionally, the membrane of each of the plurality of elongate capillary tubes has a thickness in a range of 0.1 millimetres to 0.3 millimetres.

Optionally, the pressure control device further comprises a shaft fixedly coupled to the pressure plate along an elongate axis of the spring arrangement. More optionally, the second gas flow path is provided as a hollow cylindrical portion along a length of the shaft. Yet more optionally, the shaft has a tubular structure.

Optionally, the liquid processing system further comprises a pressure relief membrane unit that is fluidically coupled to the diffusion chamber, characterised in that: - the pressure relief membrane unit comprises a first chamber and a second chamber, wherein the first chamber is fluidically sealed from the second chamber by a flexible membrane;

- the first chamber is arranged between the liquid container and the liquid inlet port; - the second chamber is arranged between the pressure control device and the gas inlet port; and

- the flexible membrane is operable to deform to allow pressure of the flow of liquid in the first chamber, above the pressure of the gas within the second chamber, to be maintained within the maximum differential pressure.

Optionally, the flexible membrane has a circular disc structure, wherein the flexible membrane has a thickness in a range of 0.1 millimetre to 1 millimetre and a diameter in a range of 3 centimetres to 10 centimetres. Optionally, the pressure relief membrane unit includes a plurality of ridges disposed on a planar surface of the flexible membrane.

In a second aspect, an embodiment of the present disclosure provides a pressure control device, characterised in that the pressure control device includes first and second gas flow paths therethrough arranged fluidically in parallel, wherein the first gas flow path operates to limit a pressure drop thereacross to a maximum pressure drop and the second gas flow path is a bleed flow path having a resistance to gas flow therethrough. Optionally, the maximum differential pressure is in a range of 3 Psi (20.684 kPa) to 10 Psi (68.948 kPa).

Optionally, the pressure control device is implemented such that:

- the first gas flow path includes a pressure plate that is maintained by a spring force against an orifice seal, the spring force being generated by a spring arrangement, wherein the maximum pressure drop occurs when a force exerted due to gas pressure on the pressure plate exceeds the spring force.

Optionally, the second gas flow path is provided as a channel in a sealing "0"-ring of the orifice seal and/or as a gas bleed hole arrangement provided on the pressure plate.

Optionally, the pressure control device further comprises a shaft fixedly coupled to the pressure plate along an elongate axis of the spring arrangement. More optionally, the second gas flow path is provided as a hollow cylindrical portion along a length of the shaft. Yet more optionally, the shaft has a tubular structure.

In a third aspect, an embodiment of the present disclosure provides a method of (for) operating a liquid processing system that diffuses, when in operation, a gas into a flow of a liquid, wherein the liquid processing system comprises: a diffusion chamber through which the flow of the liquid occurs, the diffusion chamber including a gas exchange membrane arrangement in fluidic communication with the flow of the liquid; a gas reservoir that is coupled via a gas inlet port of a gas plenum to the gas exchange membrane arrangement to supply gas, in operation, to the flow of liquid; and a liquid container that is coupled to the diffusion chamber via a liquid inlet port to supply, in operation, the flow of the liquid, characterised in that the method includes:

(i) including a pressure control device between the gas reservoir and the gas inlet port, wherein the pressure control device includes first and second gas flow paths therethrough arranged fluidically in parallel, wherein the first gas flow path operates to limit a pressure drop thereacross to a maximum pressure drop and the second gas flow path is a bleed flow path having a resistance to gas flow therethrough; and

(ii) operating the pressure control device to maintain a pressure of gas within the plenum lower than a pressure of the flow of the flow of the liquid at temporal commencement and cessation of the flow of the liquid through the diffusion chamber, wherein the pressure of the flow of liquid above the pressure of gas within the plenum is limited within a maximum differential pressure.

Optionally, the maximum differential pressure is in a range of 3 Psi (20.684 kPa) to 10 Psi (68.948 kPa).

Optionally, the gas is Carbon Dioxide (CO2) gas.

Optionally, the liquid having the diffused gas is a carbonated beverage. Additional aspects, advantages, features and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative embodiments construed in conjunction with the appended claims that follow. It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.

DESCRIPTION OF THE DRAWINGS The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.

Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein: FIG. 1 is a schematic diagram of a liquid processing system, in accordance with an embodiment of the present disclosure;

FIGs. 2, 3 and 4 are schematic illustrations of the pressure control device that is employed in the liquid processing system of FIG. 1, in accordance with an embodiment of the present disclosure; FIG. 5 is a schematic illustration of a liquid processing system, in accordance with an embodiment of the present disclosure; and FIG. 6 is an illustration of steps of a method of (for) operating a liquid processing system, in accordance with an embodiment of the present disclosure.

In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.

DESCRIPTION OF EMBODIMENTS

In overview, embodiments of the present disclosure are concerned with liquid processing systems that diffuse, when in operation, a gas into a flow of a liquid. Moreover, embodiments of the present disclosure are concerned with pressure control devices for use in aforesaid liquid processing systems. Furthermore, embodiments of the present disclosure are concerned with methods of (US English: " methods for") operating the aforementioned liquid processing systems.

Referring to FIG. 1, there is shown a schematic diagram of a liquid processing system 100, in accordance with an embodiment of the present disclosure. The liquid processing system 100 comprises a diffusion chamber 102 through which a flow of a liquid occurs in operation, wherein a gas is diffused into the flow. The flow of liquid with the gas diffused therein is provided at an output from the diffusion chamber 102. The term " diffusion ", as used throughout the present disclosure, refers to a net flow of matter from a region of high concentration of the matter to a region of low concentration of the matter, for example to allow the concentration of matter to achieve equilibrium between the regions. Furthermore, such a diffusion results in a change associated with the flow, such as a volumetric change, a concentration change, a temperature change, a pressure change and so forth.

Optionally, the diffusion chamber 102 is susceptible to being implemented in various shapes, for example in a form of a cylindrical container, a polygonal container, an elongate container having a length: width aspect ratio that is greater than 1.5: 1, more optionally having a length:width aspect ratio greater than 2: 1. Moreover, the diffusion chamber 102 is susceptible to being implemented in a wide range of sizes, depending upon requirements of the liquid processing system 100. For example, when the diffusion chamber 102 is implemented as a cylindrical container, the diffusion chamber 102 has an elongate height in a range of 150 to 400 millimetres and a diameter in a range of 30 to 120 millimetres; such a range of height and diameter enables the liquid processing system 100 to have a spatial compact form factor, thereby improving its portability and reducing its installation space requirement.

The diffusion chamber 102 is optionally fabricated from a material such as stainless steel (e.g. food grade stainless steel), mild steel, and the like; alternatively, the diffusion chamber 102 is fabricated from a polymeric material, for example PEEK®, or a ceramic material. (Polyether ether ketone (PEEK) polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts). Furthermore, the diffusion chamber 102 comprises a gas exchange membrane arrangement 104 for diffusing a gas into a flow of liquid; such an arrangement is, for example, disposed axially along a lower region of the diffusion chamber 102. Furthermore, the gas exchange membrane arrangement 104 is in fluidic communication with the flow of the liquid, such that the flow of the liquid occurs along an outer surface of the gas exchange membrane arrangement 104. Moreover, an upper region of the diffusion chamber 102 can comprise a gas plenum 106 through which the gas flows into the gas exchange membrane arrangement 104.

The liquid processing system 100 comprises a gas reservoir 108, namely any type of storage container for storing the gas therein; for example, the gas reservoir 108 is implemented as a gas cylinder equipped with an associated high-pressure regulator valve, mounted at an end region of the gas cylinder, that is coupled via a gas inlet port 110 of the gas plenum 106 to supply gas in operation to the gas exchange membrane arrangement 104. Furthermore, the diffusion chamber 102 has one or more inlet and outlet ports, such as, an inlet port for receiving a flow of a gas, and an inlet port for receiving a flow of a liquid into the diffusion chamber 102, respectively. An outlet port of the diffusion chamber 102 provides a path for a flow of the liquid comprising the diffused gas therein from the diffusion chamber 102. Such inlet and outlet ports can be implemented as orifices (or openings) on the cylindrical wall of the diffusion chamber 102. Furthermore, the inlet and outlet ports can be connected to various parts of the liquid processing system 100 using pipes, to allow flows of gas or liquid therebetween.

The compressed gas stored under high pressure within the gas reservoir 108 flows (via a pressure-dropping regulator of the gas reservoir 108) therefrom into the gas plenum 106 via the gas inlet port 110; the gas reservoir 108 is fluidically coupled to the gas inlet port 110 using a pipe that is connected between the gas reservoir 108 and the gas inlet port 110. It will be appreciated that size dimensions (such as its diameter and length) determine a pressure drop that occurs between the gas reservoir 108 and the gas plenum 106 when gas flows in operation through the pipe; the pressure-drop can therefore be temporally varying when the liquid processing system 100 is in operation.

The liquid processing system 100 comprises a liquid container 114 that is coupled to the diffusion chamber 102 via a liquid inlet port 116 to supply, in operation, the flow of the liquid, for example an un-carbonated beverage such as a still beer or ale. The liquid container 114 is optionally fabricated using at least one of: plastic, wood, aluminium, steel or a recyclable material, a biodegradable material and so forth. Generally, for increased safety during transport of liquids, the liquids are maintained in the non-pressurized (or un-carbonated) state within the liquid container 114, as aforementioned. Furthermore, the liquid container 114 is coupled to the diffusion chamber 102 via the liquid inlet port 116. The liquid inlet port 116 allows the liquid contained within the liquid container 114 to enter the diffusion chamber 102. Moreover, the liquid container 114 can be coupled to the diffusion chamber 102 using pipes, including but not limited to, plastic pipes, metallic pipes and the like. It will be appreciated that size dimensions (such as length and diameter) of the pipe determines a pressure drop that occurs between the liquid container 114 and the diffusion chamber 102 when a flows of liquid occurs in operation from the liquid container 114 to the diffusion chamber 102.

According to one embodiment, a pump 118 is used to provide a flow of the liquid from the liquid container 114 into the diffusion chamber 102. The pump 118 employs one or more components, such as piston- cylinder, vanes, screws, gerotors and so forth; optionally, the pump 118 operates by causing an excess gas pressure in a region above liquid in the liquid container 114, wherein the liquid is extracted from an outlet in a lower region of the liquid container 114.

In one example embodiment, the gas exchange membrane arrangement 104 comprises a plurality of elongate capillary tubes 112 arranged with their elongate axes disposed along (namely, parallel to within an angular deviation of less than 15°) an elongate axis of the diffusion chamber 102. The elongate capillary tubes 112 are hollow and are used to transport liquids or gases therethrough by capillary action. In one embodiment, each of the plurality of elongate capillary tubes 112 has a length in a range of 100 millimetres to 300 millimetres, more optionally in a range of 180 millimetres to 220 millimetres, and an external diameter in a range of 0.5 millimetres to 1.5 millimetres. For example, each of the plurality of elongate capillary tubes 112 has a length of 200 millimetres and an external diameter of 1 millimetre. The plurality of elongate capillary tubes 112 is in fluidic (namely, gaseous) communication with the gas plenum 106; the gas within the gas plenum 106 flows, in operation, into an upper region of each of the plurality of elongate capillary tubes 112. Subsequently, the gas flows downward through each of the plurality of elongate capillary tubes 112. Furthermore, walls of each of the elongate capillary tubes 112 allow gases flowing through the elongate capillary tubes 112 to diffuse through the walls. According to an embodiment, each of the plurality of elongate capillary tubes 112 functions as a diffusion membrane (not shown) the operated to diffuse the gas flowing through the elongate capillary tube into the flow of the liquid flowing through the diffusion chamber 102. Optionally, the membrane of each of the plurality of elongate capillary tubes 112 has a thickness in a range of 0.1 millimetres to 0.3 millimetres. Optionally, the elongate capillary tubes 112 can be fabricated from polyamide or polyimide material (for example, aramid polyamide) that has been stretched to form micropores therein (for example, as provided in a commercial 3M® product).

In operation, the diffusion chamber 102 is filled with a liquid. When carbonated liquid is not being dispensed from the system 100, the liquid within the diffusion chamber 102 is stagnant; conversely, when carbonated liquid is being dispensed from the system 100, a flow of liquid occurs through the chamber 102. When the flow of liquid occurs through the diffusion chamber 102, the liquid at a mid-point of the diffusion chamber is circa 50% carbonated relative to 100% carbonation at the outlet port 122, whereas the liquid input at the liquid inlet port 116 is 0% carbonated. It will be appreciated that when the flow ceases through the diffusion chamber 102, namely at an end of a dispensing activity, the remaining stagnant liquid in the diffusion chamber 102 all eventually becomes 100% carbonated that causes the liquid to expand, causing a pressure increase to be experienced by the elongate capillary tubes 112; such a pressure increase is referred to a being a " pressure transient". In the system 100, it is important to ensure that this pressure increase after an end of a given dispensing activity does not cause transient pressure stresses, namely damage or " blocking " of the elongate capillary tubes 112.

At a commencement of a liquid dispensing activity from the liquid processing system 100, the liquid flows from the liquid container 114 into the diffusion chamber 102 via the liquid inlet port 116; the liquid flow rises upwards within the diffusion chamber 102, along the outside of the plurality of elongate capillary tubes 112. Simultaneously, the gas flows from the gas reservoir 108 into the gas plenum 106. The gas having a higher concentration within the plurality of elongate capillary tubes 112 begins to diffuse into the liquid within the diffusion chamber 102 having a lower concentration of the gas therein; such diffusion occurs, even if the pressure of the liquid within the diffusion chamber 102 is higher than that in the gas plenum 106. In such a situation, the plurality of elongate capillary tubes 112 acts as an exchange membrane for diffusion of the gas into the liquid flowing through the diffusion chamber 102.

In an embodiment, the plurality of elongate capillary tubes 112 can be implemented as a bundle of capillary tubes, for example within a cylindrical container 120. In such an implementation, each of the plurality of elongate capillary tubes 112 will be fluidically sealed at a lower end thereof, for example by using a mass of sealing resin, by thermally fusing the capillaries to seal them, and likewise.

It will be appreciated that the liquid processing system 100 is optionally used for carbonating a beverage. Optionally, an outlet port 122 is arranged on the diffusion chamber 102 to allow flow of the carbonated beverage to be dispensed into containers 124 such as cups, glasses, mugs, vessels, "jars" and so forth, for storing and/or consuming the same. In an embodiment, a dispensing valve 126 is arranged with the outlet port 122, wherein the dispensing valve 126 controls, in operation, the flow of the carbonated beverage. For example, the dispensing valve 126 (i.e. "font") can be implemented as a tap that can be manually opened to release the liquid having the diffused gas thereof, for example at a serving bar of a public house or similar. In another example, the dispensing valve 126 can be implemented as a beer font. It will be appreciated that such a beer font can have one or more outlets for dispensing, in operation, the liquid having the diffused gas from the diffusion chamber 102.

Next, pressure transients arising in operating in the liquid processing system 100 will be described; these pressure transients represent a technical problem that potentially adversely affect an operation of the liquid processing system 100. A pressure control device 130, included between the gas reservoir 108 and the gas inlet port 110, is a control valve that controls the pressure of the gas flowing into the gas plenum 106 via the gas inlet port 110, such that the pressure of the gas is beneficially maintained within a desired pressure range. It will be appreciated that, during operation of the liquid processing system 100, such as, during commencement or cessation of operation of the liquid processing system 100, pressure transients may arise within the liquid processing system 100. Such pressure transients may be associated with a sudden increase in pressure of the gas at the gas inlet port 110 or a sudden decrease in pressure of the liquid inlet port 116. For example, during cessation of operation of the liquid processing system 100, residual gas accumulated within the gas plenum 106 potentially diffuses substantially completely (such as, within 99 to 100%) into the liquid within the diffusion chamber 102. Such a substantially complete diffusion of the gas into the liquid causes volumetric expansion of the liquid, thereby, applying pressure on the plurality of elongate capillary tubes 112 (and potentially causing stress thereon). In yet another example, during commencement of operation of the liquid processing system 100, operation of the pump 118 is not potentially adjusted properly. In such an example, a pressure of the liquid flowing from the liquid container 114 into the diffusion chamber 102 will be more than a pressure of the gas flowing from the gas reservoir 108 into the diffusion chamber 102. Such a difference between the pressure of the liquid and the pressure of the gas, potentially, in an extreme example leads to rupturing of the plurality of elongate capillary tubes 112 thereby, rendering the liquid processing system 100 inoperable; for example, the plurality of elongate capillary tubes 112 are able to withstand a pressure difference of 10 Psi thereacross without rupturing. Furthermore, such pressure transients potentially cause temporary damage to the various components of the liquid processing system 100; in such an example, pressure transients associated with flow of the gas having pressure of more than 10 Psi pressure into the plurality of elongate capillary tubes 112 potentially cause " blocking " thereof, thereby, temporarily rendering the liquid processing system 100 inoperable; " blocking " is a temporary phenomenon that results in gas pockets forming in walls of the elongate capillary tubes 112 that prevent intended gas diffusion into liquid within the diffusion chamber 102, wherein such " blocking " is experienced by users as temporary potentially unreliability of the liquid processing system 100. In such an example embodiment, the pressure control device 130 maintains pressure transients to less than 10 Psi between the gas plenum 106 and the diffusion chamber 102, thereby, enabling proper reliable operation of the liquid processing system 100. Control of such pressure transients has not hitherto been properly appreciated. The pressure control device 130 includes first and second gas paths that are arranged fluidically in parallel, wherein: (i) one of the paths provides a resistance to a gas flow therethrough, causing a pressure drop across the pressure control device 130 to occur in response to the gas flow; and

(ii) another of the paths allows a gas flow therethrough when the pressure drop developed across the pressure control device 130 exceeds a maximum threshold pressure.

It will be appreciated that the pressure control device 130 is susceptible to being implemented in various ways using hardware.

Referring next to FIG. 2, there is shown a schematic illustration of the pressure control device 130, denoted in FIG. 2 by 300, in accordance with an embodiment of the present disclosure. As shown, a second gas flow path C-D (i.e. a "bleed path") is provided as a gas bleed hole arrangement 302 provided on a pressure plate 138, wherein a through- hole is included through the pressure plate 138, such that the through- hole is arranged eccentrically on the pressure plate 138. In operation, when the force applied on the pressure plate 138 due to pressure of the flow of gas is more than a spring force provided by a helical spring arrangement 142, the pressure plate 138 is pushed away from the sealing plate 134, thereby providing a gap is formed between the pressure plate 138 and the sealing plate 134 and that provides a first flow path A-B. The first flow A-B path provides for limiting a maximum pressure that can be developed across the pressure control device 130. The gas bleed hole arrangement 302 is optionally additionally, or alternatively, provided on an "0"-ring 148 against which the pressure plate 138 seals; it will be that the gas bleed hole arrangement 302, when in operation bleeding gas therethrough, has a response time constant in the system 100 in an order to tens of seconds, more operationally greater than 1 minute. Referring next to FIG. 3, there is shown a schematic illustration of a pressure control device 130, denoted by 400, in accordance with an embodiment of the present disclosure. As shown, the pressure control device 400 comprises a shaft 402 fixedly coupled to the pressure plate 138 along an elongate axis of a spring arrangement 142. Furthermore, a second gas flow path C-D is provided via a hollow cylindrical portion 404 along a length of the shaft 402. A gas flowing through the pressure control device 400 flows into the hollow cylindrical portion 404, via a hole 406 of the base 144, causing a pressure drop to occur across the pressure control device 400. When a gap is formed between the pressure plate 138 and the sealing plate 134 due to the force exerted by the gas on the pressure plate 138 being more than the spring force, the gas flows via a first gas flow path A-B via the gap. Formation of the gap limits a maximum pressure that can be developed across the pressure control device 400.

Referring to FIG. 4, there is shown a sectional view of a pressure control device 130, denoted by 1000, in accordance with an embodiment of the present disclosure. The pressure control device 1000 comprises a casing 1002, wherein first and second gas flow paths that are fluidically in parallel for receiving a flow of a gas are provided within the casing 1002. Furthermore, the pressure control device 1000 comprises a pressure plate 1004 that is maintained by a spring force against an orifice seal 1006, the spring force being generated by a spring arrangement 1008. As shown, the spring arrangement 1008 is mounted on a base 1010 that moves, such as reciprocatively, in operation within the casing 1002. The pressure control device 1000 further comprises a shaft 1012 that is fixedly coupled to the pressure plate 1004 along an elongate axis of the spring arrangement 1008. The second flow path is a bleed flow path provided by at least one of: an elongate hole provided along the shaft 1012 (as in FIG. 4), a bleed hole included in the pressure plate 1004 (as in FIG. 2), a notch (as in FIG. 2) provided in a "0"-ring or seal against which the pressure plate 1004 seals.

Referring next to FIG. 5, there is shown a schematic illustration of a liquid processing system 100, denoted by 1100, in accordance with an embodiment of the present disclosure. As shown, the liquid processing system 1100 further comprises a pressure relief membrane unit 1102 that is fluidically coupled to the diffusion chamber 102. The pressure relief membrane unit 1102 comprises a first chamber 1104 and a second chamber 1106, wherein the first chamber 1104 is fluidically sealed from the second chamber 1106 by a flexible membrane 1108. As shown, the first chamber 1104 is arranged between the liquid container 114 and the liquid inlet port 116. The liquid flows from the liquid container 114 into the first chamber 1104 and subsequently, from the first chamber 1104 into the diffusion chamber 102 via the liquid inlet port 116. Furthermore, the second chamber 1106 is arranged between the gas reservoir 108 and the gas inlet port 110. The gas flows from the gas reservoir 108 into the second chamber 1106 and subsequently, from the second chamber 1106 into the gas plenum 106 via the gas inlet port 110. The pressure relief membrane unit 1102 comprises the flexible membrane 1108, such that the flexible membrane 1108 is implemented as a partially flexible wall between the first chamber 1104 and the second chamber 1106. Optionally, the flexible membrane 1108 has a circular disc structure, wherein the flexible membrane 1108 has a thickness in a range of 0.1 millimetres to 1 millimetre and a diameter in a range of 3 centimetres to 10 centimetres.

During operation of the liquid processing system 1100, the flow of the fluid from the pump 118 is potentially associated with pressure transients. Furthermore, during operation of the liquid processing system 1100, diffusion of an excessive quantity of gas within the liquid causes undesirable expansion of the liquid, thereby, applying pressure on the plurality of elongate capillary tubes 112, causing stress thereon and consequently, potentially causing damage to the liquid processing system 1100. The pressure of the liquid is required to be maintained within the maximum differential pressure, before flow thereof into the diffusion chamber 102 to prevent damage to the diffusion chamber 102, the gas exchange membrane arrangement 104 and so forth. Thus, the liquid is allowed to flow from the pump 118 into the first chamber 1104 and the gas is allowed to flow from the gas reservoir 108 into the second chamber 1106. Furthermore, the flexible membrane 1108 deforms, when in operation, such as towards the first chamber 1104, to allow pressure of the flow of liquid in the first chamber 1104, above the pressure of the gas within the second chamber 1106, to be maintained within the maximum differential pressure. In such an implementation, the gas flows into the second chamber 1106 and occupies a volume therein Furthermore, due to the gas occupying the volume within the second chamber 1106, a force is exerted on the flexible membrane 1108 due to pressure of the gas. Consequently, in operation, the flexible membrane 1108 deforms by a limited amount towards the first chamber 1104, thereby allowing a limited quantity of liquid (such as, a quantity less than quantity of gas within the second chamber 1106) to flow into and occupy a volume within the first chamber 1104. Furthermore, allowing the limited quantity of liquid to flow into (and subsequently, out of) the first chamber 1104 enables there to be achieved a reduction in the pressure of the liquid flowing out of the pressure relief membrane unit 1102 and into the diffusion chamber 102. Consequently, the reduction in the pressure of the liquid flowing into the diffusion chamber 102 enables the pressure of the liquid to be to be maintained within the maximum differential pressure associated with the liquid processing system 1100.

Optionally, the flexible membrane 1108 includes a plurality of ridges 1110 disposed on a planar surface of the flexible membrane 1108. Such a plurality of ridges 1110 on the planar surface (such as, on both planar surfaces) of the flexible membrane 1108 assists the bending action of the flexible membrane 1108.

Referring next to FIG. 6, there are shown steps of a method 1200 of (for) operating the liquid processing system 100, in accordance with an embodiment of the present disclosure. The method concerns employing the liquid processing system 100 to diffuse a gas into a flow of a liquid, wherein the liquid processing system 100 includes a diffusion chamber comprising a gas exchange membrane arrangement in fluidic communication with the flow of the liquid; a gas reservoir that is coupled via a gas inlet port of a gas plenum to the gas exchange membrane arrangement to supply gas in operation, to the flow of liquid; and a liquid container that is coupled to the diffusion chamber via a liquid inlet port to supply in operation, the flow of the liquid. At a step 1202, the method includes arranging for a pressure control device 130 to be included between the gas reservoir and the gas inlet port, wherein the pressure control device 130 includes first and second gas flow paths therethrough (arranged fluidically in parallel), wherein the first gas flow path operates to limit a pressure drop thereacross to a maximum pressure drop and the second gas flow path is a bleed flow path having a resistance to gas flow therethrough. At a step 1204, the method includes operating the pressure control device 130 to limit a pressure of gas within the plenum lower than a pressure of the flow of the liquid at least at temporal commencement and cessation of the flow of the liquid through the diffusion chamber, wherein the pressure of the flow of liquid above the pressure of gas within the plenum is limited to within a maximum differential pressure.

The steps 1202 to 1204 are only illustrative and other alternatives can also be provided where one or more steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein. In an example, the maximum differential pressure is in a range of 3 Psi to 10 Psi. In another example, the gas is Carbon Dioxide (CO2) gas. In yet another example, the liquid having the diffused gas is a carbonated beverage.

The liquid processing system 100 comprises the diffusion chamber, the gas reservoir that can be detachably coupled to the diffusion chamber via pipes, the liquid container that can be detachably coupled to the diffusion chamber via pipes and the pressure regulator arranged between the gas reservoir and the diffusion chamber. Such detachable components of the liquid processing system enable improved portability of the liquid processing system as compared to conventional arrangements for carbonating drinks, and also makes maintenance more convenient to implement. Moreover, the components connectable by pipes allows the liquid processing system to be arranged as per the convenience of the user, thereby, enabling the liquid processing system to be configured to have a compact and customisable form factor; for example, embodiments of the present disclosure can be used with pipes having a length greater than 50 metres, optionally more than 100 metres, and yet more optionally more than 150 metres. Moreover, use of the limited number of components to form the liquid processing system enables simple configuration and easy repair thereof. The liquid processing system comprises the pressure control device that functions to maintain the pressure of gas within the gas plenum lower than the pressure of the flow of the liquid at temporal commencement and cessation of the flow of the liquid through the diffusion chamber. Such a maintenance of the pressure of gas lower than the pressure of the flow of the liquid reduces the pressure transients created within the liquid processing system during commencement or cessation of the operation thereof. Moreover, the pressure control device functions to maintain the pressure of the flow of liquid above the pressure of gas within the maximum differential pressure for the liquid processing system. Such a maintenance of the pressure of the flow of liquid within the maximum differential pressure prevents damage, whether temporary or permanent, to the liquid processing system by maintaining the operating characteristics thereof within designed limits.

Next, steps of a method (of) for a given installer to employ when installing the liquid processing system 100 will be described:

Step SI : Choose a level (namely degree) of carbonation desired, and select a membrane head pressure required to achieve this level of carbonisation. Set up the gas supply to be 1 circle seal valve's pressure drop above this value of head pressure. Supply gas to the diffusion chamber 102.

Step S2: Start a supply pump to establish a flow of water through the diffusion chamber 102. Adjust the flow of water to a desired flow rate by either adjusting a length of a smooth bore flow restrictor pipe at a font (such as a beer font, mentioned hereinbefore, wherein "font" is a term of art referring to a tap), or a flow rate control device at the font.

Step S3: Adjust the gas pump supply pressure to set the flowing delivered pressure to the diffusion chamber 102 to be 20 kPa above the desired membrane head pressure. At this stage, software executing on a computing device coupled to the diffusion chamber 102 will measure differences in pressure and indicate via a user control panel whether or not the correct pressure has been achieved.

Step S4: Stop the flow. There will now be measured a static pressure and there is indicated to the installer that the static pressure is below the gas supply pressure (which is 1 circle seal valve pressure drop above the desired head pressure). If the difference between flowing and static pressures is too great, the installer will need to adjust the pipe runs to reduce the head loss and repeat the step S3. Modifications to embodiments of the invention described in the foregoing are possible without departing from the scope of the invention as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "consisting of", "have", "is" used to describe and claim the present invention are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. Numerals included within parentheses in the accompanying claims are intended to assist understanding of the claims and should not be construed in any way to limit subject matter claimed by these claims.