A system for processing a fluid

Abstract

The present invention provides a system for processing fluids. The system comprises a heat exchanger (900) and a controller (350). The heat exchanger (900) comprises a pipe assembly (500) for exchanging heat between a first fluid and a second fluid, the pipe assembly (500) having: an outer pipe (200) having an inner surface and an outer surface (220); one or more bulging members (230) extending from the inner surface (120) of the outer pipe (200); an inner pipe (100) carrying the first fluid and having an inner surface and an outer surface (120), the inner pipe (100) disposed within the outer pipe (200) thereby forming an annular space therebetween, the annular space carrying the second fluid; one or more protruding members (130) extending from the outer surface (120) of the inner pipe (100). The heat exchanger (900) also comprises a frame (600) for holding the pipe assembly (500).

Description

[0001] Forbes- 202421061880

[0002] 1

[0003] TITLE OF THE INVENTION

[0004] A SYSTEM FOR PROCESSING A FLUID

[0005] FIELD OF THE INVENTION

[0006]

[0001] The present invention relates to a system for processing fluids. The present invention also relates to a heat exchanger for recovering heat from the fluids.

[0007] BACKGROUND OF THE INVENTION

[0008]

[0002] Industrial facilities generate substantial quantities of waste products during their operations, which often include various chemicals and pollutants. Effective treatment and management of these industrial discharges are crucial to mitigating environmental damage and ensuring compliance with stringent regulatory standards. Amongst various possibilities, recovery of heat from the discharge presents an opportunity to enhance energy efficiency, reduce operational costs, and further minimize the environmental footprint of industrial activities. To this effect, heat exchangers are essential components in various industrial processes, including the textile industry, where they play a crucial role in the efficient transfer of thermal energy. In textile manufacturing, maintaining optimal temperatures during different stages of production is vital for ensuring product quality and process efficiency. One common application of heat exchangers in this industry involves handling hot fluids that may contain particulate matter, such as lint and chemicals.

[0009]

[0003] However, the textile industry's use of heat exchangers is often hampered by several critical issues. One of the most widely performed process steps in the textile industry is dyeing of textile material such as fabric or yarn. In a typical dyeing step, a number of cycles are performed wherein in each cycle fresh / process water at ambient temperature is mixed with the textile material and chemicals followed by heating to provide a specific color or dye on the textile material. In each cycle, the mixture of water, material and chemicals is heated indirectly with the steam generated in a fossil fuel fired steam boiler. This heating is typically done in the range of 80°C to 130°C depending on the material being dyed in each cycle. Further, the temperature is likely to vary in each cycle during a complete dyeing process. Once, a cycle is completed, water and chemicals are drained from the dyeing machine whereas the material is retained for further cycle. The drained mixture of water and chemicals is typically referred to as a dye liquor. For the next cycle, fresh or process water at ambient temperature is again added along with chemicals in the dyeing machine which contains the material. Heating of the mixture is repeated in the dyeing machine with steam and drained at 80°C to 130°C once the cycle is completed. In a typical Forbes- 202421061880

[0010] 2 dyeing process, at least 10-15 such cycles are repeated (1 batch). After one batch is completed, the next batch with fresh material to be dyed is taken and the cycles are repeated. There can be 2 to 3 batches in a day. During the dyeing step, the material sheds loose threads like particles called lint or fluff which are one of the major contaminations in the textile industry.

[0011]

[0004] Heat exchangers can be used to indirectly transfer heat from the drained dye liquor to pre-heat fresh or process water to reduce the steam required for heating in the dyeing machine, thereby reducing the fossil fuel in the boiler and hence carbon dioxide reduction.

[0012]

[0005] During operation of the heat exchangers in the textile industry for waste heat recovery from contaminated fluid stream containing drained chemicals and lint, there are several challenges associated. For instance, lint gets accumulated in the minuscule flow paths of the heat exchangers, such as a plate heat exchanger (PHE), and a shell and tube heat exchanger (STHE), thereby choking or completely blocking the flow and rendering them non-operational. The presence of even a small amount of these materials can choke the flow path, thereby increasing their maintenance and operating costs. Moreover, cleaning the heat exchangers is also a menace.

[0013]

[0006] Various modifications to the existing heat exchangers have been proposed. One of the very basic modifications includes placing filters or screens before the heat exchanger. This arrangement shifts the choking problem from heat exchange to these filters / screens. This not only increases the capital expenditure but also increases the operating cost, thereby making the waste heat recovery economically unviable. Further, these solutions also impact the efficiency of the heat exchanger by lowering overall heat transfer coefficient (Uc) and higher approach temperature.

[0014]

[0007] Further, a simple straight double pipe heat exchanger is also liable to several limitations and challenges when employed in the textile industry. For instance, the lint blocks or chocks inside the inner pipe, particularly at the sharp U-bends at the end of each leg. Chocking is also prominent in and around the joints where the U-bend is connected. This is in addition to the challenges posed by the U-bend itself, i.e., high pressure drop. Additionally, the presence of joints also adds up to the overall cost of the heat exchanger. Furthermore, the contaminated fluid stream containing lint cannot be flown inside the annular gap created between the outer pipe and the inner pipe due to choking caused by accumulation of lint.

[0015]

[0008] Other modifications include the use of a spacer between the inner and outer pipe. The primary objective of the spacers is to ensure uniform annular space between the inner pipe and outer pipe. The spacers are provided on the outer surface of the inner pipe with each being in physical contact with the inner surface of the outer pipe. However, there are several limitations with the use of spacers, particularly on the inner surface of the outer pipe. Firstly, manufacturing Forbes- 202421061880

[0016] 3 pipes with spacers has a technical constraint owing to the difficulty in achieving the desired cross-section. Further, there is also a short circuit of heat transfer from inner pipe to outer pipe through these fins or spacers instead of fluid in the annular space. Also, the presence of multiple joints in the heat exchanger results in several inward protrusions towards the center of the outer pipe which obstructs these spacers or fins.

[0017]

[0009] To summarize, the existing heat exchanger designs have the following limitations - costly and bulky systems, higher auxiliary power consumption, higher pressure drop, manufacturing and assembly challenges, frequent chocking issues, inaccessible inner tube, large number of joints prone to leakage and repair, inefficient utilization of heat transfer area, and increased heat loss to environment. Moreover, none of the existing designs improve both reliability and uptime of the heat exchanger and reducing the fouling or scaling due to contaminated fluid. Furthermore, effective cleaning of heat exchanger remains a challenge till date.

[0018]

[0010] Thus, there is a need in the art for a system for processing fluids such as industrial discharge by waste heat recovery therefrom using a heat exchanger and subsequently cleaning the heat exchanger, thereby solving one or more of the abovementioned problems.

[0019] SUMMARY OF THE INVENTION

[0020] [Oi l] One aspect of the present invention relates to a heat exchanger. The heat exchanger comprises a pipe assembly for exchanging heat between a first fluid and a second fluid. The pipe assembly comprises an outer pipe having an inner surface and an outer surface. An inner pipe carries the first fluid and has an inner surface and an outer surface. The inner pipe is disposed within the outer pipe thereby forming an annular space therebetween, the annular space carrying the second fluid. One or more bulging members extend from the inner surface of the outer pipe within the annular space, and one or more protruding members extend from the outer surface of the inner pipe within the annular space. The heat exchanger also comprises a frame for holding the pipe assembly. The frame has at least one column fixedly attached to a base, a plurality of arms extending outwardly from the at least one column and a holder disposed at an end of each of the arm for holding the pipe assembly.

[0021]

[0012] In an embodiment, the first fluid is at a temperature Tl, and the second fluid is at a temperature T2 whereby Tl > T2.

[0022]

[0013] In another embodiment, the pipe assembly has a bend radius defined as a radius of curvature of the pipe assembly as it bends or coils, wherein a ratio between the bend radius and an outer diameter of the inner pipe is at least 10: 1. Forbes- 202421061880

[0023] 4

[0024]

[0014] In yet another embodiment, each of the bulging members is aligned with a corresponding protruding member such that the one or more bulging members and the one or more protruding members are positioned directly opposite to each other in the annular region.

[0025]

[0015] In still another embodiment, each of the bulging members is angularly offset from a corresponding protruding member such that the one or more bulging members and the one or more protruding members are positioned at angular intervals ranging between 60° to 120°.

[0026]

[0016] In an embodiment, the one or more bulging members and the one or more protruding members is continuous.

[0027]

[0017] In a further embodiment, the one or more bulging members or the one or more protruding members is formed by pressing a flexible rod on the outer surface of the outer pipe or the inner pipe.

[0028]

[0018] In still another embodiment, the one or more bulging members are positioned relative to the one or more protruding members such that the one or more bulging members and the one or more protruding members have a phase shift, the first flexible rod and the second flexible rod forming a wave-like structure.

[0029]

[0019] In another embodiment, the holder has one or more projections extending from an inner surface of the holder. The holder pressing the outer pipe inwardly towards the inner pipe thereby forming the one or more bulging members.

[0030]

[0020] In an embodiment, the heat exchanger comprises one or more aerodynamic components being disposed at predetermined locations on the outer surface of the outer pipe, each of the projection fitting into each of the aerodynamic component and pressing the outer surface of the outer pipe inwardly towards the inner pipe, thereby forming the one or more bulging members.

[0031]

[0021] Another aspect of the present invention relates to a system for processing fluids. The system comprises the above heat exchanger, a first pump, a second pump, a first valve, a second valve, and a controller. The first pump is coupled with the inner pipe and configured to pump the first fluid to the inner pipe from a first end of the pipe assembly. The second pump is coupled with the outer pipe and configured to pump the second fluid to the outer pipe from a second end of the pipe assembly. The first valve is coupled with the first pump and the pipe assembly, the first valve configured to turn on and off a flow of the first fluid. The second valve is coupled with the second pump and the pipe assembly, the second valve configured to turn on and off a flow of the second fluid. The controller is coupled with the first pump, the second pump, the first valve, and the second valve. The controller is configured to operate the first pump, the second pump, the first valve, and the second valve for ensuring counter current flow of the first fluid and the second fluid in the heat exchanger, thereby resulting in an improved heat transfer coefficient. Forbes- 202421061880

[0032] 5

[0033]

[0022] In an embodiment, the system is configured to descale the heat exchanger. The system comprises a dosing pump, a dosage valve, and a modulating control valve. The dosing pump is coupled with the inner pipe and configured to pump a descaling agent to the inner pipe. The dosage valve is coupled with the dosing pump and the pipe assembly, the dosage valve configured to turn on and turn off a flow of the descaling agent. The modulating control valve is coupled with the first valve, the second valve, and the dosage valve. The modulating control valve is configured to regulate flow of the first fluid, the second fluid and the descaling agent. The controller is coupled with the dosing pump and the dosage valve. The controller is configured to receive a start signal, turnoff the second valve to direct the flow of the second fluid to the inlet of the inner pipe, monitor the flow of the first fluid and the second fluid to an inlet of the inner pipe for a first predetermined time, thereby agitating the inner surface of the inner pipe, turnoff the first valve after the first predetermined time is exhausted, monitor the flow of the second fluid to the inlet of the inner pipe for a second predetermined time, thereby cleaning the inner surface of the inner pipe, turnoff the first valve and the second valve and monitor the flow of the descaling agent to the inlet of the inner pipe for a third predetermined time, thereby descaling the inner surface of the inner pipe.

[0034]

[0023] In another embodiment, the controller is further configured to turnoff the dosage valve and monitor the flow of the second fluid to the inlet of the inner pipe for a fourth predetermined time, thereby flushing the inner surface of the inner pipe.

[0035]

[0024] In yet another embodiment, the first predetermined time, the second predetermined time, the third predetermined time, and the fourth predetermined time, independent of each other, is maintained such that the inner pipe is free from contamination.

[0036] BRIEF DESCRIPTION OF THE DRAWINGS

[0037]

[0025] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.

[0038] Figure 1 shows a perspective view of a system for processing fluids showcasing a heat exchanger and a controller in accordance with an embodiment of the invention.

[0039] Figure 2 shows a perspective view of a pipe assembly having an elliptical configuration in accordance with an embodiment of the invention. Forbes- 202421061880

[0040] 6

[0041] Figure 3a shows a side view of a pipe assembly having a helical configuration in accordance with an embodiment of the invention.

[0042] Figure 3b shows a side view of a pipe assembly having a spiral configuration in accordance with an embodiment of the invention.

[0043] Figures 4a to 4c show a front-sectional view of pipes showcasing one or more protruding members and one or more bulging members having different configurations and aligned directly opposite to each other in accordance with an embodiment of the invention.

[0044] Figures 5a to 5c show a front-sectional view of pipes showcasing one or more protruding members and one or more bulging members having different configurations and angularly offset with each other in accordance with an embodiment of the invention.

[0045] Figure 6a shows a front sectional view of a frame having a single column for holding the pipe assembly of Figure 2 in accordance with an embodiment of the invention.

[0046] Figure 6b shows a side view of a semicircular holder partially encapsulating an outer pipe in the frame of Figure 6a in accordance with an embodiment of the invention.

[0047] Figure 7a shows a front sectional view of a frame having two columns and semi circular holders in accordance with an embodiment of the invention.

[0048] Figure 7b shows a front-sectional view of a frame having two columns and circular holders in accordance with an embodiment of the invention.

[0049] Figure 8 shows a perspective view of a pipe showcasing one or more protruding members and one or more bulging members formed by a first flexible rod and a second flexible rod in accordance with an embodiment of the invention.

[0050] Figure 9 shows a side view of the pipe of Figure 8 in accordance with an embodiment of the invention.

[0051] Figures 10a and 10b show a front-sectional view of a pipe showcasing one or more aerodynamic components and formation of one or more bulging members in accordance with an embodiment of the invention.

[0052] Figure 11 shows a block diagram of the system in accordance with an embodiment of the invention.

[0053] DETAILED DESCRIPTION OF THE INVENTION

[0054]

[0026] Various features and embodiments of the present invention here will be discernible from the following further description thereof, set out here under.

[0055]

[0027] An aspect of the present invention is directed towards a system for processing fluids. Forbes- 202421061880

[0056] 7

[0057]

[0028] In an embodiment, the system comprises of a heat exchanger for recovering heat from a fluid such as an industrial discharge. The fluid comprises a dye liquor containing drained chemicals and lint from a dyeing unit of a textile industry. The heat exchanger does not require pretreatment of the fluid to remove the lint.

[0058]

[0029] During heat recovery from the fluid the heat exchanger is likely to be fouled due to accumulation of lint and scaling due to the chemicals. Accordingly, the system is further configured to descale the heat exchanger. The system comprises a controller for cleaning the heat exchanger. The controller ensures removal of fouling caused by lint and scaling due to chemicals inside the heat exchanger. Thus, the system optimizes the requirement for maintenance due to fouling and / or scaling.

[0059]

[0030] Another aspect of the present invention is directed towards a heat exchanger for exchanging heat between the fluids.

[0060]

[0031] In an embodiment, the heat exchanger comprises a pipe assembly for exchanging heat between a first fluid and a second fluid, the pipe assembly having: an outer pipe having an inner surface and an outer surface; one or more bulging members extending from the inner surface of the outer pipe; an inner pipe carrying the first fluid and having an inner surface and an outer surface, the inner pipe disposed within the outer pipe thereby forming an annular space therebetween, the annular space carrying the second fluid; one or more protruding members extending from the outer surface of the inner pipe. The heat exchanger also comprises a frame for holding the pipe assembly, the frame having at least one column fixedly attached to a base; a plurality of arms extending outwardly from the at least one column; and a holder disposed at an end of each of the arm in the plurality of arms for holding the pipe assembly from the outer pipe.

[0061]

[0032] In another embodiment, the fluids being processed in the system include the first fluid and the second fluid. The second fluid recovers the heat from the first fluid.

[0062]

[0033] Figure 1 shows a system 1000 in accordance with an embodiment of the invention. As shown, the system 1000 comprises a heat exchanger 900 and a controller 350. The heat exchanger 900 comprises a pipe assembly 500 having a configuration selected from elliptical, helical, circular, and spiral. Each of these configurations are illustrated in Figures 1, 2, 3a, and 3b, respectively.

[0063]

[0034] The heat exchanger 900 comprises a frame 600 for holding the pipe assembly 500. The pipe assembly 500 is shown through figures 4 and 5. The pipe assembly 500 is a substantially concentric pipe assembly 500 having an outer pipe 200 and an inner pipe 100, whereby an annular space is formed between the outer pipe 200 and the inner pipe 100. The inner pipe 100 may be optionally supported at one or more bends of the pipe assembly 500, thereby ensuring the Forbes- 202421061880

[0064] 8 inner pipe 100 is held inside the outer pipe 200. For instance, the inner pipe 100 may be supported at a first bend and a last bend in the pipe assembly 500. Further, since the inner pipe 100 is made of a stiff material or a non-flexible material it remains stiff or does not sag onto the outer pipe 200. The inner pipe 100 carries a first fluid and the outer pipe 200 carries a second fluid in the annular space between the outer pipe 200 and the inner pipe 100. The first fluid is a hot fluid, such as but not limited to, a dye liquor containing drained chemicals and lint from a dyeing unit of a textile industry. Typically, the dye liquor generated in a dyeing unit is received in a dye liquor drain tank. The dye liquor in the drain tank is at a temperature ranging between 80°C to 130°C. The second fluid is a cold fluid, such as but not limited to, a process water or fresh water which is at ambient temperature. A separate water tank holds the process water generated during various operations in a textile manufacturing plant. Further, fresh water is added to the water tank from time to time to ensure constant supply of cold fluid for recovering heat from the hot fluid. Thus, the first fluid is at a temperature Tl, and the second fluid is at a temperature T2 whereby Tl > T2.

[0065]

[0035] As shown in Figure 2, the pipe assembly 500 has a first end 510 and a second end 520. In an embodiment, at the first end 510 the inner pipe 100 receives the first fluid and at the second end 520 the outer pipe 200 receives the second fluid. Herein, the first end 510 serves as an inlet for the first fluid to flow into inner pipe 100 whereas the second end 520 serves as an outlet for the first fluid to flow out of the inner pipe 100. Similarly, the second end 520 serves as an inlet for the second fluid to flow into outer pipe 200 whereas the first end 510 serves as an outlet for the second fluid to flow out of the outer pipe 200. Accordingly, the first fluid and the second fluid flow in a counter current manner inside the pipe assembly 500. The counter current flow ensures an improved heat transfer coefficient and a lower approach temperature. Further, vertical orientation of the pipe assembly 500 with gravity assisted drain ensures no accumulation of the first fluid within the inner pipe 100, thereby reducing the probability of scaling and fouling caused due to lint.

[0066]

[0036] Referring to Figure 4a, the outer pipe 200 has an inner surface 210 and an outer surface 220 (as shown in Figure 10b). The outer surface 220 forms a circumferential portion of the outer pipe 200. Further, one or more bulging members 230 extend from the inner surface 210 of the outer pipe 200 within the annular space.

[0067]

[0037] The inner pipe 100 also has an inner surface 110 and an outer surface 120 (not shown in Figures). The inner pipe 100 carries the first fluid. As shown in Figures 4(a-c) and 5(a-c), the inner pipe 100 is disposed substantially concentrically within the outer pipe 200, thereby forming the annular space therebetween. The annular space carries the second fluid. Further, one or more Forbes- 202421061880

[0068] 9 protruding members 130 extend from the outer surface 120 of the inner pipe 100 within the annular space.

[0069]

[0038] In an embodiment, each of the outer pipe 200 and the inner pipe 100 is a continuous pipe of suitable dimensions. Herein, dimension refers to one or more of the following: length, diameter, and thickness. The dimension of the outer pipe 200 and the inner pipe 100 is selected based on various parameters, such as but not limited to, heat transfer rate, fluid properties, temperature difference, heat transfer coefficient, heat loads, flow rates, pressure difference, space constraints, operational conditions, and the like.

[0070]

[0039] As shown in Figure 2, the pipe assembly 500 is made of continuous inner pipe 100 disposed substantially concentrically within continuous outer pipe 200. Also shown is a bend radius R1 of the pipe assembly 500. The bend radius R1 is sufficient enough to ensure choke free flow of the first fluid and reduce pressure drops around a bend area caused by bending of the outer pipe 200 and the inner pipe 100. Herein, bend radius R1 refers to a radius of curvature of pipe as it bends or coils. In an embodiment, a ratio between the bend radius R1 of the pipe assembly 500 and an outer diameter OD of the inner pipe 100 is at least 10: 1. The bend radius R1 in this ratio further helps in generating secondary velocity in fluid streams (both first and second fluids), which enhances turbulence and heat transfer coefficient. Further, higher bend radius R1 also ensures ease of manufacturing and reducing thinning of pipes during bending process, thereby improving reliability (i.e., reduction in failures due to thinning).

[0071]

[0040] In an embodiment, the continuous pipes have advantages such as least resistant flow path, secondary velocity in bend area, no obstruction for the lint in the dye liquor, less leakage, lower manufacturing cost, lower pressure drop, increased heat transfer rate, reduced power consumption, and cost effectiveness.

[0072]

[0041] In another embodiment, each of the outer pipe 200 and the inner pipe 100 is made by connecting multiple pipes of varying length using a non-flexible joint such as a weld. The presence of non-flexible joint ensures a continuous flow path for the first fluid and the second fluid.

[0073]

[0042] In an embodiment, the outer pipe 200 is made from a flexible material and the inner pipe 100 is made from a non-flexible material. In an exemplary embodiment, the inner pipe 100 is made from non-flexible material selected from stainless steel, copper, mild steel, and aluminum. Further, the outer pipe 200 is made from flexible material selected from rubber, composite, polymers, and flexible steel-based materials. The flexible material allows for easy removal and cleaning of the outer pipe 200 to ensure longevity of the pipe assembly 500 and minimize Forbes- 202421061880

[0074] 10 downtime of the heat exchanger 900. Further, the flexible material also allows for the formation of one or more bulging members 230 in the outer pipe 200, as described hereinbelow.

[0075]

[0043] Referring to Figures 4a to 4c, each of the bulging members 230 on the inner surface 210 of the outer pipe 200 is aligned with a corresponding protruding member 130 on the outer surface 120 of the inner pipe 100 such that the one or more bulging members 230 and the one or more protruding members 130 are positioned directly opposite to each other in the annular region. Herein, the one or more bulging members 230 and the one or more protruding members 130 are spaced apart such that they do not make a physical contact.

[0076]

[0044] In an alternate embodiment, as shown in Figures 5a to 5c, each of the bulging members 230 on the inner surface 210 of the outer pipe 200 is angularly offset from a corresponding protruding member 130 on the outer surface 120 of the inner pipe 100 such that the one or more bulging members 230 and the one or more protruding members 130 are positioned at angular intervals ranging between 60° to 120°.

[0077]

[0045] The absence of physical contact between the one or more bulging members 230 and the one or more protruding members 130 enhances turbulence in the second fluid flowing inside the annular space, thereby increasing the heat transfer coefficient without increasing the pressure drop.

[0078]

[0046] Further, the one or more protruding members 130 can be made of the same material as that of the inner pipe 100 or a different one. The one or more bulging members 230 is made of the same material as that of the outer pipe 200.

[0079]

[0047] Figure 6a shows the frame 600 for holding the pipe assembly 500. In an embodiment, the frame 600 has at least one column 610 fixedly attached to a base. Herein, the base includes ground, or an elevated platform fixed on the ground.

[0080]

[0048] The frame 600 has a plurality of arms 620 extending outwardly from the at least one column 610, and a holder 630 disposed at an end of each of the arm 620.

[0081]

[0049] Each of the holder 630 is configured to hold the pipe assembly 500 from the outer pipe 200 at multiple locations. The dimensions of the holder 630 correspond with the dimensions of the pipe assembly 500 to ensure that the pipe assembly 500 is tightly held within the frame 600 without any sagging. In this context, dimensions refer to one or more of the following: diameter and thickness. Further, as shown in Figure 7a the holder 630 is configured to at least partially encapsulate the circumferential portion of the outer pipe 200. Alternately, as shown in Figure 7b, the holder 630 completely encapsulates the circumferential portion of the outer pipe 200.

[0082]

[0050] In an embodiment, as shown in Figures 6a and 6b, the holder 630 has one or more projections 631 extending from an inner surface of the holder 630. The holder 630 holds the Forbes- 202421061880

[0083] 11 outer pipe 200 of the pipe assembly 500. Further, the holder 630 presses the outer pipe 200 inwardly towards the inner pipe 100, thereby forming one or more bulging members 230 on the inner surface 210 of the outer pipe 200.

[0084]

[0051] In an embodiment, the one or more projections 631 are disposed on the inner surface of the holder 630 at predetermined locations. The predetermined locations are selected based on various factors, such as but not limited to, weight of the pipe assembly, heat transfer rate, type of first and second fluid, pressure drop, heat transfer coefficient, material of construction for inner and outer pipes, and the likes.

[0085]

[0052] In an embodiment, each of the protruding members 130, projections 631, and bulging members 230 have same dimensions. In this context, dimension refers to one or more of the following: length, breadth, height, and diameter. Further, protruding members 130, projections 631, and bulging members 230 have any suitable shape, such as but not limited to, circular, square, rectangular, and the likes. Furthermore, each of the protruding members 130 are disposed on the inner pipe 100 using suitable means such as but not limited to adhesives, and welding. Similarly, each of the projections 631 are disposed on the holder 630 using suitable means such as but not limited to adhesives, and welding.

[0086]

[0053] In an embodiment, the one or more bulging members 230 is disposed at predetermined locations on the inner surface 210 of the outer pipe 200. Further, the one or more protruding members 130 is formed at predetermined locations on the outer surface 120 of the inner pipe 100. This is shown in Figures 4(a-c) and 5(a-c). The predetermined locations are selected based on various factors, such as but not limited to, heat transfer rate, type of first and second fluid, pressure drop, heat transfer coefficient, material of construction for inner and outer pipes, and the likes. The predetermined locations are typically 60 to 120° apart from each other.

[0087]

[0054] In an embodiment, the one or more bulging members 230 and the one or more protruding members 130, independent of each other, is continuous. As shown in Figure 8, the one or more bulging members 230 is formed by pressing a first flexible rod on the outer surface 220 of the outer pipe 200. Further, the one or more protruding members 130 is formed by a second flexible rod wound around the outer surface 120 of the inner pipe 100. The flexible rod (first and second both) refers to an elongated strand or filament composed of metal or metal alloys such as but not limited to copper, aluminum, steel, and the likes.

[0088]

[0055] In an embodiment, the second flexible rod can be disposed on the outer surface 120 of the inner pipe 100 using suitable means such as but not limited to adhesives, and welding. The second flexible rod represents the protruding member 130 on the inner pipe 100. Forbes- 202421061880

[0089] 12

[0090]

[0056] In another embodiment, the first flexible rod is disposed on the holder 630 such that when the holder 630 is tightened on the outer pipe 200, the first flexible rod is pressed on the outer surface 220 of the outer pipe 200, thereby forming the bulging members 230. Herein, the holder 630 is devoid of one or more projections 631. Further, the holder 630 is tightened at predetermined locations on the outer surface 220 of the outer pipe 200 to ensure that the bulging members 230 are continuous.

[0091]

[0057] In an embodiment, suitable dimensions of the first flexible rod and the second flexible rod may be selected to ensure that there is no physical contact between the bulging members 230 and the protruding members 130. In this context, dimensions include one or more of the following: length, thickness, and diameter.

[0092]

[0058] In another embodiment, the bulging members 230 formed by the first flexible rod is aligned with the protruding members 130 formed by the second flexible rod such that the bulging members 230 and the protruding members 130 are positioned directly opposite to each other.

[0093]

[0059] In an alternate embodiment, the bulging members 230 formed by the first flexible rod are positioned relative to the protruding members 130 formed by the second flexible rod such that the bulging members 230 and the protruding members 130 have a phase shift. As shown in Figure 9, the first flexible rod and the second flexible rod appear as a wave-like structure having a phase angle. The phase shift between the wave-like structure formed by the first flexible rod and the second flexible rod refers to the difference in their phase angles, resulting in a temporal displacement of one wave relative to the other.

[0094]

[0060] Similar to bulging members 230 and the protruding members 130 shown in Figures 4(a- c) and 5(a-c), the bulging members 230 and the protruding members 130 formed by the first flexible rod and the second flexible rod respectively, also enhances the turbulence in the second fluid flowing inside the annular space, thereby increasing the heat transfer coefficient without increasing the pressure drop.

[0095]

[0061] In another embodiment, one or more aerodynamic components 240 are disposed at predetermined locations on the outer surface 220 of the outer pipe 200, as shown in Figure 10a.

[0096]

[0062] Referring to Figure 10b, each of the projection 631 in the holder 630 and each of the aerodynamic component 240 on the outer surface 220 form a male-female arrangement such that the projection 631 fits into the aerodynamic component 240 and presses the outer surface 220 of the outer pipe 200 inwardly towards the inner pipe 100, thereby forming the one or more bulging members 230. For instance, a leading end of the projection 631 has an external thread and the aerodynamic component 240 has an internal thread. Other suitable combinations of the projection 631 and the aerodynamic component 240 forming the male-female arrangement are Forbes- 202421061880

[0097] 13 well within the purview of the present invention. Alternately, the aerodynamic component 240 can be directly welded or pasted using suitable adhesives to the outer pipe 200.

[0098]

[0063] The one or more aerodynamic components 240 are disposed on the outer pipe 200 using suitable means, such as adhesive or welding. Further, the one or more aerodynamic components 240 can be made of suitable materials, such as but not limited to, flexible material of the outer pipe 200 or a different material. Similarly, the one or more protruding members 130 can be made of suitable materials, such as but not limited to, non-flexible material of the inner pipe 100 or a different material.

[0099]

[0064] The one or more protruding members 130 on the inner pipe 100, as described hereinabove, not only changes the velocity boundary layer of the second fluid but also makes the flow more turbulent, thereby enhancing heat transfer rates. Further, the one or more protruding members 130 also act as fins on the inner pipe 100, thereby increasing the overall surface area for heat transfer. The physical mechanisms causing the enhancement are the generation and extensions of strong longitudinal vortices due to the one or more protruding members 130 and the corresponding one or more bulging members 230 which are reactive with the thermal boundary layer. Additionally, a combination of the one or more protruding members 130 and the one or more bulging members 230 also aid in aligning the inner pipe 100 within the outer pipe 220 when the second fluid flows inside the annular space. Thus, the combination allows for self- alignment of the inner pipe 100 and the outer pipe 220 and increases swirl generation in the flow, thereby enhancing heat transfer with reduced pressure drop and scale formation.

[0100]

[0065] The pipe assembly 500, when held by the holder 630 remains suspended in air, with each coil separated from another coil, thereby ensuring efficient heat exchange between the first fluid and the second fluid. Overall, the frame 600 ensures concentricity and uniform annular gap in the pipe assembly 500. The frame 600 further ensures that the outer pipe 200 is properly supported and any spring like oscillations or vibrations of the inner pipe 100 is minimized, without impacting swirl generation caused by the protruding members 130 and the bulging members 230.

[0066] The system of the present invention comprises the heat exchanger as discussed above. Accordingly, the embodiments pertaining to the heat exchanger are applicable to the system as well.

[0101]

[0067] In an embodiment, the system comprises the heat exchanger 900; a first pump 310 coupled with the inner pipe 100 and configured to pump the first fluid to the inner pipe 100 from a first end of the pipe assembly 500; a second pump 320 coupled with the outer pipe 200 and configured to pump the second fluid to the outer pipe 200 from a second end of the pipe assembly 500; a first valve 312 coupled with the first pump 310 and the pipe assembly 500, the Forbes- 202421061880

[0102] 14 first valve 312 configured to turn on and off a flow of the first fluid; a second valve 322 coupled with the second pump 320 and the pipe assembly 500, the second valve 322 configured to turn on and off a flow of the second fluid; and a controller 350 coupled with the first pump 310, the second pump 320, the first valve 312, and the second valve 322. The controller 350 is configured to operate the first pump 310, the second pump 320, the first valve 312, and the second valve 322 for ensuring counter current flow of the first fluid and the second fluid in the heat exchanger 900, thereby resulting in an improved heat transfer coefficient.

[0103]

[0068] The heat exchanger 900 comprises the pipe assembly 500. The pipe assembly 500 comprises the outer pipe 200 and the inner pipe 100. The inner pipe 100 carries the first fluid. Further, the inner pipe 100 is disposed within the outer pipe 200 thereby forming the annular space therebetween, the annular space carrying the second fluid.

[0104]

[0069] Referring to Figures 1 and 11, the system 1000 comprises a first pump 310, a second pump 320, a first valve 312, a second valve 322, and a controller 350.

[0105]

[0070] The first pump 310 is coupled with the inner pipe 100 of the pipe assembly 500. The first pump 310 is configured to pump the first fluid to an inlet of the inner pipe 100.

[0106]

[0071] The second pump 320 is coupled with the outer pipe 200 of the pipe assembly 500. The second pump 320 is configured to pump the second fluid to an inlet of the outer pipe 200.

[0107]

[0072] The first valve 312 is coupled with the first pump 310 and the pipe assembly 500. The first valve 312 is configured to turn on and off a flow of the first fluid. Similarly, the second valve 322 is coupled with the second pump 320 and the pipe assembly 500. The second valve 322 is configured to turn on and off a flow of the second fluid.

[0108]

[0073] The controller 350 is coupled with the first pump 310, the second pump 320, the first valve 312, and the second valve 322. The controller 350 is configured to operate the first pump 310, the second pump 320, the first valve 312, and the second valve 322 for ensuring counter current flow of the first fluid and the second fluid in the heat exchanger 900, thereby resulting in an improved heat transfer coefficient. Thus, the system 1000 ensures that the fluids are processed within the heat exchanger 900, thereby enabling maximum heat transfer between the first fluid and the second fluid.

[0109]

[0074] In another embodiment, the system 1000 is further configured to descale the heat exchanger 900. For this, the system 1000 comprises a dosage valve 332, a dosing pump 330, and a modulating control valve 340.

[0110]

[0075] The dosing pump 330 is coupled with the inner pipe 100 of the pipe assembly 500. The dosing pump 330 is configured to pump a descaling agent to the inlet of the inner pipe 100. Forbes- 202421061880

[0111] 15

[0112]

[0076] The dosage valve 332 is coupled with the dosing pump 330 and the pipe assembly 500. The dosage valve 332 is configured to turn on and turn off the flow of the descaling agent.

[0113]

[0077] The modulating control valve 340 is coupled with the first valve 312, the second valve 322 and the dosage valve 332. The modulating control valve 340 is configured to regulate flow of the first fluid, the second fluid and the descaling agent.

[0114]

[0078] In an embodiment, the first valve 312, the second valve 322 and the dosage valve 332 are on / off valves providing for a fixed flow rate of the first fluid, the second fluid and the descaling agent, when turned on. These valves do not have the capability to allow variation or control in the flow rate. Hence, the modulating control valve 340 controls the flow rate of the first fluid, the second fluid and the descaling agent. The variation in flow rates of the first fluid, the second fluid and the descaling agent ensure efficiency in the system 1000.

[0115]

[0079] The system 1000 further includes a pressure sensor 360 coupled at the inlet of the inner pipe 100, a pressure sensor 370 coupled at an outlet of the inner pipe 100, and a non-return valve 380 coupled with the first valve 312, the modulating control valve 340, and the inlet of the inner pipe 100. Further, a dye liquor drain tank 390 is coupled with the first pump 310. A level sensor is coupled with the controller 350 and the dye liquor tank 390.

[0116]

[0080] For descaling the heat exchanger 900, the controller 350 is further coupled with the dosing pump 330 and the dosage valve 332. The controller 350 is configured to receive a start signal. In an embodiment, the start signal is generated in response to a user’s input on an input device. This input device may include, but is not limited to, a keyboard, a touchscreen, a button, a switch, or any other suitable interface that allows the user to initiate the generation of the start signal.

[0117]

[0081] In another embodiment, the controller 350 is configured to receive a start signal automatically without any input from the user. Said otherwise, the start signal is generated based on preset conditions. Suitable conditions which may trigger the start signal include level in the dye liquor drain tank 390, pressure drop across the inlet and outlet of the inner pipe 100, and frequency based (e.g., daily or weekly). The generation of the start signal may be dependent on two levels within the condition. For instance, the start signal is generated if the dye liquor level (determined by the level sensor 391) within the dye liquor drain tank 390 is more than a first predetermined dye liquor level, and the dye liquor level is less than a second predetermined dye liquor level. The start signal may also be generated when the pressure drop across the inlet and outlet of the inner pipe 100 is more than a predetermined pressure drop value. Alternately, the start signal may be generated depending on the frequency of rinsing or cleaning of the inner pipe Forbes- 202421061880

[0118] 16

[0119] 100. For instance, if the rinsing or cleaning of the inner pipe 100 was carried out more than 24 hours ago, the start signal may be generated.

[0120]

[0082] The controller 350 is also configured to turn off the second valve 322 to direct the flow of the second fluid to the inlet of the inner pipe 100. Herein, the controller 350 communicates the start signal to the second valve 322 to turn off the second valve 322.

[0121]

[0083] The controller 350 is further configured to monitor the flow of the first fluid and the second fluid to the inlet of the inner pipe 100 for a first predetermined time, thereby agitating the inner surface 110 of the inner pipe 100. Herein, a mixed flow of the first fluid and the second fluid is fed to the inlet of the inner pipe 100 for the first predetermined time. A higher pressure drop across the inlet of the inner pipe 100 and outlet of the inner pipe 100 is maintained to ensure an increase in velocity and turbulence in the mixed flow, thereby scrubbing and agitating the inner surface 110 of the inner pipe 100. The pressure drop between the inlet and the outlet of the inner pipe 100 is determined from the pressure sensor 360 and the pressure sensor 370.

[0122]

[0084] The controller 350 is further configured to turn off the first valve 312. Once the first predetermined time is exhausted, the first valve 312 is turned off. Thereafter, the controller 350 is configured to monitor the flow of the second fluid to the inlet of the inner pipe 100 for a second predetermined time, thereby cleaning the inner surface 110 of the inner pipe 100.

[0123]

[0085] The controller 350 is subsequently configured to: turn off the first valve 312 and the second valve 322; and monitor the flow of the descaling agent to the inlet of the inner pipe 100 for a third predetermined time, thereby descaling the inner surface 110 of the inner pipe 100. The descaling agent is dosed in suitable amounts to ensure any scaling or contamination on the inner surface 110 of the inner pipe 100 is removed. Suitable descaling agents include such as, but not limited to, ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), acetic acid, citric acid, formic acid, hydrochloric acid, and the like.

[0124]

[0086] Subsequently, the inner pipe 100 is flushed with the second fluid. For this, the controller 350 is configured to: turn off the dosage valve 332 and monitor the flow of the second fluid to the inlet of the inner pipe 100 for a fourth predetermined time, thereby flushing the inner surface 110 of the inner pipe 100.

[0125]

[0087] In an embodiment, the start signal can be generated by the user in one or more of the following situations:

[0126] - Before the start of heat exchange between the first fluid and second fluid,

[0127] - After completion of the heat exchange between the first fluid and second fluid,

[0128] - Increase in pressure drop at the inlet of the inner pipe 100 or lower heat transfer,

[0129] - Periodic - daily / weekly / monthly Forbes- 202421061880

[0130] 17

[0131]

[0088] In another embodiment, the first, second, third, and fourth predetermined time is customized depending on the fouling of the inner pipe 100. This ensures that the inner pipe 100 is free from contamination (majorly lint) prior to its subsequent use.

[0132]

[0089] Advantageously, the present invention ensures lower pressure drop, lower power consumption, proper concentricity and gap, uniform support, higher heat transfer coefficient, and an economic system.

[0133]

[0090] Further, the present invention also ensures that there is no lint accumulation and hence choking in the inner pipe. The system also ensures that any scaling and fouling on the inner surface of the inner pipe, which is the main heat transfer surface, is prevented, thereby resulting in optimum performance. This extends the life of the heat exchanger.

[0134]

[0091] The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since the modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to the person skilled in the art, the invention should be construed to include everything within the scope of the disclosure.

Claims

Forbes- 20242106188018CLAIMS1. A heat exchanger (900) comprising: a pipe assembly (500) for exchanging heat between a first fluid and a second fluid, the pipe assembly (500) comprising: an outer pipe (200) having an inner surface and an outer surface (220); an inner pipe (100) carrying the first fluid and having an inner surface (110) and an outer surface (120), the inner pipe (100) disposed within the outer pipe (200) thereby forming an annular space therebetween, the annular space carrying the second fluid; one or more bulging members (230) extending from the inner surface (210) of the outer pipe (200) within the annular space; and one or more protruding members (130) extending from the outer surface (120) of the inner pipe (100) within the annular space; and a frame (600) for holding the pipe assembly (500), the frame (600) having: at least one column (610) fixedly attached to a base; a plurality of arms (620) extending outwardly from the at least one column (610); and a holder (630) disposed at an end of each of the arm (620) for holding the pipe assembly (500).

2. The heat exchanger (900) as claimed in claim 1, wherein the first fluid is at a temperature Tl, and the second fluid is at a temperature T2 whereby T1 > T2.

3. The heat exchanger (900) as claimed in claim 1, wherein the pipe assembly (500) has a bend radius (Rl) defined as a radius of curvature of the pipe assembly (500) as it bends or coils, wherein a ratio between the bend radius (Rl) and an outer diameter of the inner pipe (100) is at least 10: 1.

4. The heat exchanger (900) as claimed in claim 1, wherein each of the bulging members (230) is aligned with a corresponding protruding member (130) such that the one or more bulging members (230) and the one or more protruding members (130) are positioned directly opposite to each other in the annular region.

5. The heat exchanger (900) as claimed in claim 1, wherein each of the bulging members (230) is angularly offset from a corresponding protruding member (130) such that the oneForbes- 20242106188019 or more bulging members (230) and the one or more protruding members (130) are positioned at angular intervals ranging between 60° to 120°.

6. The heat exchanger (900) as claimed in claim 1, wherein the one or more bulging members (230) and the one or more protruding members (130) is continuous.

7. The heat exchanger (900) as claimed in claim 6, wherein the one or more bulging members (230) or the one or more protruding members (130) is formed by pressing a flexible rod on the outer surface of the outer pipe (200) or the inner pipe (100).

8. The heat exchanger (900) as claimed in claim 7, wherein the one or more bulging members (230) are positioned relative to the one or more protruding members (130) such that the one or more bulging members (230) and the one or more protruding members (130) have a phase shift, the first flexible rod and the second flexible rod forming a wavelike structure.

9. The heat exchanger (900) as claimed in claim 1, wherein the holder (630) has one or more projections (631) extending from an inner surface of the holder (630), the holder (630) pressing the outer pipe (200) inwardly towards the inner pipe (100) thereby forming the one or more bulging members (230).

10. The heat exchanger (900) as claimed in one or more of claims 1 to 12 comprising one or more aerodynamic components (240) being disposed at predetermined locations on the outer surface (220) of the outer pipe (200), each of the projection (631) fitting into each of the aerodynamic component (240) and pressing the outer surface (220) of the outer pipe (200) inwardly towards the inner pipe (100), thereby forming the one or more bulging members (230).

11. A system (1000) for processing fluids, the system comprising: a heat exchanger (900) comprising a pipe assembly (500) for exchanging heat between a first fluid and a second fluid, the pipe assembly (500) comprising: an outer pipe (200) having an inner surface and an outer surface (220); an inner pipe (100) carrying the first fluid and having an inner surface (110) and an outer surface (120), the inner pipe (100) disposed within the outer pipe (200) thereby forming an annular space therebetween, the annular space carrying the second fluid;Forbes- 20242106188020 a first pump (310) coupled with the inner pipe (100) and configured to pump the first fluid to the inner pipe (100) from a first end of the pipe assembly (500); a second pump (320) coupled with the outer pipe (200) and configured to pump the second fluid to the outer pipe (200) from a second end of the pipe assembly (500); a first valve (312) coupled with the first pump (310) and the pipe assembly (500), the first valve (312) configured to turn on and off a flow of the first fluid; a second valve (322) coupled with the second pump (320) and the pipe assembly (500), the second valve (322) configured to turn on and off a flow of the second fluid; and a controller (350) coupled with the first pump (310), the second pump (320), the first valve (312), and the second valve (322), the controller (350) configured to operate the first pump (310), the second pump (320), the first valve (312), and the second valve (322) for ensuring counter current flow of the first fluid and the second fluid in the heat exchanger (900), thereby resulting in an improved heat transfer coefficient.

12. The system (1000) as claimed in claim 11, wherein the system (1000) is configured to descale the heat exchanger (900) and comprises: a dosing pump (330) coupled with the inner pipe (100) and configured to pump a descaling agent to the inner pipe (100); a dosage valve (332) coupled with the dosing pump (330) and the pipe assembly (500), the dosage valve (332) configured to turn on and turn off a flow of the descaling agent; a modulating control valve (340) coupled with the first valve (312), the second valve (322), and the dosage valve (332), the modulating control valve (340) configured to regulate flow of the first fluid, the second fluid and the descaling agent; the controller (350) coupled with the dosing pump (330) and the dosage valve (332), the controller (350) configured to: receive a start signal; turnoff the second valve (322) to direct the flow of the second fluid to the inlet of the inner pipe (100); monitor the flow of the first fluid and the second fluid to an inlet (510) of the inner pipe (100) for a first predetermined time, thereby agitating the inner surface (110) of the inner pipe (100); turnoff the first valve (312) after the first predetermined time is exhausted;Forbes- 20242106188021 monitor the flow of the second fluid to the inlet of the inner pipe (100) for a second predetermined time, thereby cleaning the inner surface (110) of the inner pipe (100); turnoff the first valve (312) and the second valve (322); and monitor the flow of the descaling agent to the inlet of the inner pipe (100) for a third predetermined time, thereby descaling the inner surface (110) of the inner pipe (100).

13. The system (1000) as claimed in claim 12, wherein the controller (350) is further configured to: turnoff the dosage valve (332); and monitor the flow of the second fluid to the inlet of the inner pipe (100) for a fourth predetermined time, thereby flushing the inner surface (110) of the inner pipe (100).

14. The system (1000) as claimed in claim 12 or 13, wherein the first predetermined time, the second predetermined time, the third predetermined time, and the fourth predetermined time, independent of each other, is maintained such that the inner pipe (100) is free from contamination.

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