Dual-purpose, multilayered foam generating & breaking device

Abstract

ABSTRACT Disclosed is a dual-purpose, multi-layered device for foam generation and breakage. The device comprises a first flow path defined on a first flow layer wherein, the ingress into and egress out of the first flow path is facilitated by an inlet and outlet respectively, a second flow path defined on a second flow layer wherein, the second flow path is accessible via an opening. The device further comprises a hydrophilic fluid interface medium sandwiched between the first and second flow paths. Owing to the contact between the first flow path and the interface medium, content within in the first flow path permeates the interface medium

Description

TECHNICAL FIELD

[001] The present disclosure relates to foam generation and foam degradation and more particularly to a novel, dual-purpose, multilayered, foam generating & breaking device.BACKGROUND

[002] Foam generation and degradation, or foam breaking, are critical operations in various industrial and scientific processes. Foam is generated by trapping of the gas within a liquid resulting in the formation of small bubbles within said liquid. This is often facilitated by low surface energy components like surfactants. Foam is required for many commercial applications such as cosmetics, food and pharmaceuticals, fire-fighting, making lightweight foamed concrete, foam fractionation, foam floatation, dust suppression, and hand wash solutions, to name a few. However, on the other hand, foam formation is undesirable in many process operations such as alcohol and beverage production, soy protein recovery, bioprocesses, bio industries, and environmental pollution remediation techniques. In all such cases, the foam is generated as an unwanted product or traps the desired product, and therefore foam breaking is necessary.

[003] Currently, most of the foam generation and foam breaking devices are designed for specific applications and are difficult to integrate into existing designs. Especially, foam generation requires high-pressure air streams thereby making the corresponding facilitating equipment bulky. The common defoaming methods involve chemical and physical processes. Chemical defoaming introduces additional chemicals to the process, increasing operating costs and waste stream chemicals. Physical defoaming strategies using moving components such as impellers and rotating disks can cause shear damage to the product or microbes, and mechanical processes have high operating costs and complicated designs.

[004] To improve foam handling, a portable and scalable device for foam generation and breaking that can be integrated into existing designs is necessary. Additionally, a device that can produce and break foam, provides dual functionality and versatility, making it of significant commercial interest. The device should not require high-pressure air streams or moving components, and the defoaming process should not introduce additional chemicals to the process. A physical defoaming strategy that enhances drainage and collapses the foam structure without damaging the product or microbes can be a suitable solution.

[005] In conclusion, foam is ubiquitous in various industries, and a portable, scalable, and versatile device for foam generation and breaking that does not require high-pressure air streams, moving components, or introduce additional sensitive chemicals to the process can be of significant commercial interest.SUMMARY

[006] An embodiment of the present disclosure teaches a novel, multilayered device that, while addressing all the drawbacks of the prior art, serves a dual purpose as both foam generating & breaking device. The device comprises multiple, planar, rectangular primary layers viz., a pair of first and second flow layers, a center layer and a pair of first and second extremity cover layers. A rectangular gasket layer is fitted between two primary layers so as to prevent leakage and short-circuiting therebetween. The gasket layer is preferably made of nitrile rubber. The primary and gasket layers are stacked together and fastened along the perimeters thereof leading to the assemblage of the device.

[007] A flow layer comprises a centrally disposed, serpentine, laterally thorough flow path integrally defined therewithin. The flow path extends between a start and an end point. Notably, the thickness of the flow layer and that of the corresponding flow path are identical. For ease of reference, the flow paths on the first and second flow layers are referred to as first and second flow paths respectively. Disposed between the first and second flow layers is the center layer comprising a central rectangular opening. A porous, hydrophilic fluid interface medium, which preferably comprises melamine sponge, is snugly fitted within the rectangular opening. For ease of reference, the assemblage between the first and second flow layers and the center layer and the corresponding gasket layers is referred to as the core assembly.

[008] The core assembly is disposed between the pair of cover layers. The first cover layer comprises an inlet and an outlet, which are in fluid communication with the start and end points of the first flow path respectively. Similarly, the second cover layer comprises cover openings, which are in fluid communication with the start and end points of the second flow path respectively.

[009] In order to generate foam from the device, a foaming liquid comprising surfactant-loaded liquid is pumped into the inlet from a reservoir via a first blow pump. As the foaming liquid enters and travels through the first flow path, said foaming liquid permeates and eventually saturates the melamine sponge. As enabled by a second blow pump, air is simultaneously blown through the cover openings. As the air from the second blow pump flows through the melamine sponge (saturated with the foaming liquid), the air gets trapped within the foaming liquid causing the generation of foam, which is eventually emanated from the outlet.

[0010] In order to extract foaming liquid from foam, foam is pumped into the inlet by means of a blow pump. The foam moves over the melamine sponge along the length of the first flow path whereby, the melamine sponge, by virtue of it being hydrophilic, absorbs the foaming liquid. At this juncture, the air trapped within the foam is released and moves along the rest of the flow path and eventually moves out of the device via the outlet. Simultaneously, with the continued absorption of the foaming liquid, the melamine sponge becomes increasingly saturated with the foaming liquid. At this point, as enabled by a suction pump, the foaming liquid is drawn out from the melamine sponge making space for further absorption of the foaming liquid from the foam. The foaming liquid without any air comes out from the cover openings.

[0011] Other features and advantages will become apparent from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings.BRIEF DESCRIPTION OF FIGURES

[0012] FIG. 1 is, according to an embodiment of the present disclosure, an isometric view of the device.

[0013] FIG. 2 is, according to an embodiment of the present disclosure, a side view of the device.

[0014] FIG. 3 is, according to an embodiment of the present disclosure, an exploded view of the device.

[0015] FIG. 4 is, according to an embodiment of the present disclosure, a plan view of a flow layer.

[0016] FIG. 5 & 6 are, according to an embodiment of the present disclosure, plan views of assembled and disassembled center layer respectively.

[0017] FIG. 7 is, according to an embodiment of the present disclosure, a plan view of a first gasket layer.

[0018] FIG. 8A & 8B are, according to an embodiment of the present disclosure, a plan view of assembled and dissembled cover layer respectively.

[0019] FIG. 9 is, according to an embodiment of the present disclosure, a schematic diagram of the foam generation process.

[0020] FIG. 10 is, according to an embodiment of the present disclosure, microscopic representation of how foam is generated.

[0021] FIG. 11 is, according to an embodiment of the present disclosure, a schematic diagram of the foam breaking process.

[0022] FIG. 12 is, according to an embodiment of the present disclosure, microscopic representation of how foam is broken down into foaming liquid.

[0023] FIG. 13A & 13B are graphical representations of the volume of foam generated vs. the time for the surfactant concentration of 0.16 moles / liter and 0.24 moles / liter respectively.

[0024] FIG. 14 is a graphical representation of the channel length required to break foam vs. the foam flow rate corresponding to the surfactant concentration of 0.08 moles / liter and 0.16 moles / liter.DETAILED DESCRIPTION

[0025] Embodiments of the present disclosure are explained in detail below with reference to the various figures. In the following description, numerous specific details are set forth to provide an understanding of the embodiments and examples. However, those of ordinary skill in the art will recognize several equivalent variations of the various features provided in the description. Furthermore, the embodiments and examples may be used together in various combinations.

[0026] The present disclosure teaches a novel, multilayered device that, while addressing the drawbacks of the prior art, serves a dual purpose as both foam generating & breaking device (hereinafter referred to as the "device"). The device does not include any moving parts or any complicated design, which translates into easier manufacturing. Further, the device does not require the usage of chemicals thus entirely preventing the corresponding drawbacks associated therewith. The device is capable of being integrated in line with an existing system resulting in cheaper operating costs.

[0027] Referring to FIGs. 1 through 3, although the device 10 is multilayered, for exemplary purposes, the number of layers is limited to nine comprising five primary layers 11 and four gasket layers 13. The primary layers 11 comprise a pair of first and second flow layers 12, a center layer 14 and a pair of first and second extremity cover layers 16. Each primary layer 11 comprises a planar rectangular member, the outer dimensions of each of which are identical to one another. Alternatively, the primary layer 11 could be of any shape, viz., circular, oval, hexagonal, etc., as long as the functionality thereof is not affected. The primary layer 11 could be made of any material such as, metal, plastic, acrylic, etc. In one embodiment, the primary layer 11 is made of a transparent or translucent material for monitoring purposes.

[0028] Referring to FIGs. 1, 2 and 3, a gasket layer 13 is fitted between two primary layers 11 so as to prevent leakage and short-circuiting therebetween. A gasket layer 13 is also of rectangular shape, the thickness of which is significantly lesser than that of a primary layer 11. The gasket layer 13 is preferably made of compressible nitrile rubber, which is chemically inert to the fluids involved in the foam generation and breaking processes. However, the gasket layer 13 may be made of any sealing material as long as the functionality thereof and that of the device is not compromised in any way. The outer shape of the gasket layer 13 is preferably the same as that of the primary layer 11, which is rectangular. If any other shape of the primary layer is used, the gasket layer shape is to be modified accordingly. The primary 11 and gasket layers 13 are stacked together and fastened at the corners or along the perimeters thereof leading to the assemblage of the device. The fasteners comprise nuts and bolts. Alternatively, the assemblage can be accomplished by means of any other suitable fasteners known in the art. The four gasket layers 13 comprise a pair of first and second serpentine gasket layers 24 and a pair of first and second rectangular gasket layers 26.

[0029] Referring to FIGs. 1 through 4, each of the first and second flow layers 12 comprises a centrally disposed, serpentine flow path 18 integrally defined therewithin. The flow path 18 extends between a start and an end point. Alternatively, the flow path 18 could be of any other suitable shape such as, interdigitated, pin type, spiral, zig-zag, straight, wavy, etc. In one embodiment, there to be multiple parallel flow paths 18. The flow path 18 is laterally thorough extending between the opposing sides (or surfaces) of the corresponding flow layer 12. This translates into the thickness of the flow layer 12 and that of the corresponding flow path 18 being identical. For ease of reference, the flow paths 18 on the first and second flow layers 12 are referred to as first and second flow paths 18 respectively.

[0030] Referring to FIGs. 1 through 3, 5 and 6, disposed between the first and second flow layers 12 is the center layer 14 comprising a central rectangular opening 20. In other embodiments, the central opening 20 can be of any suitable shape. A hydrophilic fluid interface medium is snugly fitted within the rectangular opening 20. The interface medium comprises a rectangular melamine sponge 22, which when fitted within the rectangular opening 20, the surfaces of the center layer 14 are flush with those of said melamine sponge 22. Alternatively, any suitable porous, hydrophilic structure can be employed in lieu of the melamine sponge 22.

[0031] Referring to FIGs. 1 through 3 and 7, the first serpentine gasket layer 24 is sandwiched between the first cover layer 16 and the first flow layer 12 and the second serpentine gasket layer 24 is sandwiched between the second flow layer 12 and the second cover layer 16. Each serpentine gasket layer 24 comprises a centrally-disposed serpentine opening 28, the shape of which corresponds with that of the first flow path 18 as the serpentine gasket layer 24 and the flow layer 12 are appropriately aligned.

[0032] Referring to FIG. 3, the first rectangular gasket layer 26 is disposed between the first flow layer 12 and the center layer 14, while the second rectangular gasket layer 26 is sandwiched between the center layer 14 and the second flow layer 12. Each rectangular gasket layer 26 comprises a centrally-disposed rectangular opening 20, that dimensions of which align with those of the rectangular opening 20 on the center layer 14. For ease of reference, the assemblage between the first and second flow layers 12 and the center layer 14 and the rectangular gasket layers 13 therebetween is referred to as the core assembly.

[0033] Referring to FIGs. 1 through 3, the core assembly is disposed between the pair of cover layers 16 and the serpentine gasket layers 24 as explained in the earlier body of text. The first cover layer 16 comprises an inlet 32 and an outlet 34, which are in fluid communication with the start and end points of the first flow path 18 respectively. Similarly, the second cover layer 16 comprises cover openings 36, which are in fluid communication with the start and end points of the second flow path 18 respectively. In one embodiment, there could be any number of cover openings 36 on the second cover layer 16, which could have a fluid communication with the second flow path 18 at any point thereof.

[0034] Referring to FIGs. 9 & 10, in order to generate foam from the device 10, content comprising foaming liquid 38, which in turn comprises surfactant-loaded liquid is pumped into the inlet 32 (FIG. 8A) from a reservoir via a first blow pump 40. As the foaming liquid 38 enters and travels through the first flow path 18 (FIG. 4), due to the hydrophilicity of the melamine sponge 22, said foaming liquid 38 permeates and eventually saturates the melamine sponge 22. As enabled by a second blow pump 40, air 46 is simultaneously blown through the cover openings 36 (FIG. 8B) via Swagelok-type connections 42. The flow rate of the first blow pump is to be maintained such that the hydrophilic melamine sponge 22 remains saturated with the entering of the foaming liquid 38. The air 46 from the second blow pump 40, as it moves through the foaming liquid saturated melamine sponge 22, gets trapped within the foaming liquid 38 and emerges in the form of foam 44 in the first flow field. With the combined pressure exerted by the first and the second blow pumps 40, the generated foam 44 is pushed through the first flow path. The generated foam 44 is emanated from the outlet 34 (FIG. 8A). Notably, the first and second blow pumps 40 comprise peristaltic pumps. However, other types of blow pumps may be employed as long as the desired outcome is achieved. In one embodiment, multiple first flow layers 12 and the corresponding number of gasket layers 13 may be employed to increase the intake of foaming liquid 38. The multiple first flow layers 12 are stacked in parallel such that, the flow paths 18 thereof are aligned. Proportionately, the number of center layers 14 and the number of corresponding gasket layers 13 may also be increased to accommodate the foaming liquid 38 intake at the inlet 32 (FIG. 8A). In one embodiment, the flow path length along with the overall dimensions of all primary layers 12 and the gasket layers 13 may be increased to accommodate a higher volume of the foaming liquid 38. In another embodiment, the width of each of the flow path 18 can be increased to accommodate a higher volume of the foaming liquid 38. In yet another embodiment, both the length and the width of the flow paths 18 may be increased to accommodate even higher volume of the foaming liquid 38. However, in all these embodiments, the individual primary layers 11 and the gasket layers 13 should aptly match as discussed in the earlier body of text.

[0035] Referring to FIGs. 11 and 12, in order to extract foaming liquid 38 by breaking foam 44, initially, the melamine sponge 22 is prewetted with water (or even the foaming liquid 38 itself) to enhance the foaming liquid absorbing capacity of the melamine sponge 22. Thereafter, content comprising foam 44 (pertaining to a foamy foaming liquid) within a reservoir is pumped into the inlet 32 (FIG. 8A) by means of a blow pump 40. As the foam 44 moves through the first flow path 18 over the wet melamine sponge layer 22, the foaming liquid 38 pertaining to the foam 44 is drained and absorbed into the melamine sponge 22 due to its hydrophilicity. At this juncture, the air trapped within the foam 44 is released and air 46 moves along the residual length of the flow path 18 and emerges out of the outlet 34. The absorbed foaming liquid 38 in the melamine sponge 22 is sucked out into the second flow path 38, as enabled by a suction pump 48, and emerges from the cover openings 36 (FIG. 8B) via Swagelok-type connections 42. The removal of the absorbed foaming liquid 38 from the melamine sponge 22 renders it unsaturated, which in turn makes space for the continued absorption of the foaming liquid 38 from the incoming foam 44. The consistent suction pressure leads to the foaming liquid 38 being collected from the suction pump 48 and thereafter be received into a reservoir. The resultant air 46 from the breakage of the foam 44 is released via the outlet 34 (FIG. 8A). In one embodiment, multiple first flow layers 12 and the corresponding number of gasket layers 13 may be employed so as to increase the intake of the foaming liquid 38. The multiple first flow layers 12 are stacked in parallel such that, the flow paths 18 thereof are aligned. Proportionately, the number of center layers 14 (with the melamine sponges 22) and the corresponding number of gasket layers 13 may also be increased so as to accommodate the potential increase of the foaming liquid volume permeating the melamine sponge 22. In one embodiment, the flow path length along with the overall dimensions of all primary layers 11 and the gasket layers 13 may be increased to accommodate a higher volume of the foaming liquid 38. In another embodiment, the width of each of the flow path 18 can be increased to accommodate a higher volume of the foaming liquid 38. In yet another embodiment, both the width and the length may be increased in order to accommodate even higher volume of the foaming liquid 38. However, in all the cases, the primary layers 11 and the gasket layers 13 should match as discussed in the earlier body of text.

[0036] To demonstrate and quantify the foam generation process, a foaming liquid comprising a surfactant sodium dodecyl sulfate was prepared in DI water. The experiments were conducted for two different concentrations of the surfactant, specifically, 0.24 M (moles / liter) and 0.16 M (moles / liter) solution. The solution was pumped into the device's inlet, where the foaming liquid's flow rate was kept at 1 ml / min. Two different flow rates of the air were studied, 78 ml / min and 100 ml / min. The foam generated from the device was collected, and the volume of the foam was measured as a function of time. FIGs. 13A & 13B show the volume of the foam generated as a function of time for the foaming liquid with a surfactant concentration of 0.16 M (moles / liter) and 0.24 M (moles / liter), respectively.

[0037] A linear curve fitting was done, and the R2 value was close to 1 for all the cases, highlighting consistent foam generation. The slope of the curve was used to evaluate the foam generation rate. The foam generation rate and the corresponding process parameters are described in Table 1. The results show that a higher air flow rate and a lower surfactant concentration led to a higher foam generation rate.Table 1: foam generation datasheet

[0038] In order to quantitatively demonstrate the foam-breaking process, the foam was generated using a foaming liquid with sodium dodecyl sulfate as the surfactant dissolved in DI water. The foam was made with two different surfactant concentrations, specifically, 0.08 M (moles / liter) and 0.16 M (moles / liter) solution. Before the experiments, the melamine sponge was prewetted with the foaming solution to enhance the liquid absorbing capacity of the melamine sponge and also to evaluate the steady-state behavior. The foam from a reservoir was pumped into the inlet, where the foam flow rate was varied, and the length of the channel required to break down the foam completely was evaluated. The flow channel length required to break the foam as a function of foam flow rate is presented in FIG. 14. As can be observed, the length of the flow channel required to break the foam increases with an increase in the inlet flow rate of the foam. The increase in the flow channel length leads to an increase in this area of the melamine sponge which comes in contact with the foam. This occurs as the surface area necessary for absorbing the foaming liquid and releasing the trapped air increases when more amount of foam is pumped into the system. A near-linear correlation can be obtained from the plot with R2 values close to 0.98. The slope of the plot and the foam-breaking data sheet is provided in Table 2. From Table 2, it can be observed that the slope of the linear correlation is similar in both cases. The slope indicates the increase in the channel length required for breaking the foam for a unit increase in the foam flow rate, expressed with the units cm / (ml.min-1) and referred to as the required channel rate. The similar slope of the two plots indicates that the increase in the surfactant concentration does not significantly affect the required channel rate. The results also indicate that the device can be used to break the foam over a wide range of foam flow rates. Table 2: foam breaking datasheet

[0039] In conclusion, the data shows the foam generation and breaking feasibility using the same device. As can be observed, the channel length plays an important role in determining the foam handling capacity of the device. Specifically, for the foam-breaking process, the absorption of the foaming liquid occurs at the surface of the melamine sponge, and hence, increasing the surface area with which the foam comes in contact enhances the drainage behavior and foam-breaking capacity. The above can be achieved by increasing the flow channel length, increasing the flow channel width, or any other equally appropriate approach. While the above study uses a serpentine flow field, different flow field designs can be utilized to realize the fluid and the melamine sponge contact. In the foam generation process, the inlet air flow rate is crucial in determining the foam generation rate.

[0040] Embodiments and examples are described above, and those skilled in the art will be able to make various modifications to the described embodiments and examples without departing from the scope of the embodiments and examples.

[0041] Although the processes illustrated and described herein include series of steps, it will be appreciated that the different embodiments of the present disclosure are not limited by the illustrated ordering of steps. Some steps may occur in different orders, some concurrently with other steps apart from that shown and described herein. In addition, not all illustrated steps may be required to implement a methodology in accordance with the present disclosure. Moreover, it will be appreciated that the processes may be implemented in association with the apparatus and systems illustrated and described herein as well as in association with other systems not illustrated.

Claims

1. A dual-purpose, multi-layered foam generating & breaking device comprising a plurality of primary layers, the device comprising: (a) a first flow path defined on a first flow layer, the ingress into and egress out of the first flow path facilitated by an inlet and outlet respectively; (b) a second flow path defined on a second flow layer, the second flow path accessible via at least one cover opening; and (c) a hydrophilic fluid interface medium sandwiched between the first and second flow paths; wherein, owing to the contact between the first flow path and the interface medium, content within in the first flow path permeates the interface medium; each of the first and second flow layers being a primary layer.

2. The device of claim 1, wherein each flow path is serpentine.

3. The device of claim 1, wherein each flow path is laterally thorough extending between the opposing surfaces of the corresponding flow layer thereof.

4. The device of claim 1 further comprising a pair of extremity cover layers, each of which disposed next to a flow layer, wherein the inlet, the outlet and the at least one cover opening are disposed on said cover layers; a cover layer being a primary layer.

5. The device of claim 1, wherein the interface medium comprises melamine sponge, which is disposed within a center layer such that surfaces of the melamine sponge are flush with those of the center layer; the center layer being a primary layer.

6. The device of claim 1, wherein a gasket layer is sandwiched between two primary layers to prevent fluid leakage, short-circuiting, or a combination thereof between said two primary layers.

7. The device of claim 1 in the event of being a foam generator, the content in the first flow path comprises a foaming liquid comprising liquid mixed with surfactant.

8. The device of claim 7, wherein air is pumped into the at least one cover opening so that, owing to the foaming liquid being permeated within the interface medium combined with the air pressure effect on the interface medium, foam is generated and is collected at the outlet.

9. The device of claim 1 in the event of the same functioning as a foam breaking device, the content in the first flow path comprises foam that is pumped into the inlet via a blow pump; said foam pertaining to a foamy foaming liquid.

10. The device of claim 9, wherein a suction pump is connected to the at least one cover opening and is deployed whereby, the foam is broken down and the resultant foaming liquid is absorbed by the interface medium and is eventually released via the at least one cover opening; the interface medium being prewetted.