A high-pressure high-density fin cold stamping forming method of a plate-fin heat exchanger

Abstract

The application discloses a cold stamping forming method of high-pressure high-density fins of a plate-fin heat exchanger. The high-pressure high-density fins have the characteristics of small pitch and large fin thickness. The stamping tool has thin thickness, large forming pressure and friction, and high requirements for mechanical strength, wear resistance and toughness of the tool. The tool is prone to deformation, wear and even breakage during the forming process. The application proposes a cold stamping forming method of high-pressure high-density fins, which changes the traditional double-side 180-degree forming with two small tools with equal thickness into single-side 90-degree forming with a large tool with large thickness and a small tool with small thickness. The forming force is applied by the large tool, and the small tool is used for controlling the fin pitch and bearing small displacement lateral force. The method reduces the requirements for the mechanical properties of the tool material and the forming difficulty of the fins, and is suitable for the forming of the fins of the high-pressure high-density micro-channel plate-fin heat exchanger with large thickness and small pitch.

Description

Technical Field

[0001] This invention belongs to the field of compact heat exchangers and their precision machining technology, specifically relating to a cold stamping method for high-pressure, high-density fins. Background Technology

[0002] Plate-fin heat exchangers, as a type of highly efficient and compact heat exchange equipment, are widely used in numerous industries such as large-scale petrochemicals, coal chemicals, air separation, natural gas liquefaction, and steel metallurgy. Their advantages are mainly reflected in high-efficiency heat transfer, large heat exchange area per unit volume, compact structure, and wide operating temperature range. The fins, as the core component of the plate-fin heat exchanger, are typically manufactured by cold stamping thin aluminum sheets using a modular mold and then brazing. The design and manufacturing of the fins have a decisive influence on the overall performance of the heat exchanger.

[0003] From a heat transfer perspective, the microscale is defined as between 1 micrometer and 1 millimeter, the fine scale as 100 micrometers to 1 millimeter, and anything larger than 1 millimeter is considered macroscale. Research reveals that at the microscale, because the surface area to volume ratio can reach millions, the interaction between the temperature and velocity fields is much stronger, significantly enhancing heat transfer efficiency. This results in a larger heat exchange area per unit volume, thereby greatly improving heat transfer efficiency and reducing costs. When the flow channel size is reduced to the microchannel level of 0.5mm to 1mm, the convective heat transfer coefficient can increase by 50% to 100%. Therefore, microchannel plate-fin heat exchangers with high-pressure, high-density fin designs can achieve higher heat transfer efficiency. For the same heat exchange demand, the overall heat exchanger is smaller, consumes less material, and is more economical.

[0004] Currently, high-pressure, high-density finned microchannel plate-fin heat exchangers are used in ultra-large air separation equipment and coal chemical equipment. While ensuring the same heat exchange capacity, this new type of heat exchanger exhibits lower material consumption, smaller size, lighter weight, lower cost, and higher pressure resistance and economic benefits.

[0005] However, with the development of high-pressure, high-density fins, the fin thickness is constantly increasing, while the pitch is becoming increasingly smaller; the traditional stamping process, such as... Figure 1 As shown, two thin-walled blades of equal thickness are used for 180° forming on both sides. The blades not only bear the forming force but also have pitch control function. The blades are subjected to large forming forces, which places high demands on the mechanical properties of the blades.

[0006] Meanwhile, as the fin spacing decreases and the fin thickness increases, the required cutting tool thickness becomes thinner and thinner. The forming force on the mold and cutting tool continues to increase, and the requirements for the mechanical properties of the material also increase, making the mold and cutting tool prone to deformation, wear and even breakage.

[0007] Existing fin processing technology has reached a bottleneck, becoming the biggest obstacle restricting the development of heat exchangers. In summary, solving the stamping forming process problem for high-pressure, high-density fins is key to the manufacturing of microchannel plate-fin heat exchangers. Summary of the Invention

[0008] This invention addresses the shortcomings of traditional methods by proposing a cold stamping forming method for high-pressure, high-density fins, such as... Figure 2 As shown, this method employs two sets of blades and their stamping drive mechanism. Each set consists of a large blade with a large thickness and a small blade with a small thickness, using 90° forming on one side. The vertical forming force, composed of stamping force and friction, is applied by the large blade with a large thickness, while the small blade is only used to control the fin pitch and withstand a very small lateral displacement force, thus breaking through the fin processing technology limits of high-pressure, high-density microchannel plate-fin heat exchangers with large thickness and small fin pitch.

[0009] The present invention provides a method for cold stamping forming of high-pressure, high-density fins for plate-fin heat exchangers. The stamping equipment used includes two sets of blades, upper and lower, and their stamping drive mechanisms. The blade sets include a large blade and a small blade arranged side by side. The width of the large blade is greater than the width of the small blade. The two sets of stamping drive mechanisms are used to drive the two sets of blades to move up and down and laterally, respectively. The method for cold stamping high-pressure, high-density fins of this plate-fin heat exchanger includes the following steps: Step (1): Place the aluminum alloy plate to be processed between the upper and lower cutter groups that are aligned with each other.

[0010] Step (2): Move the upper knife down and press it against the top surface of the aluminum alloy plate.

[0011] Step (3): Press the large blade upwards.

[0012] Step (4): Lower the large blade downwards to reset.

[0013] Step (5): The upper blade assembly drives the fins to move laterally.

[0014] Step (6): Reset the upper knife upwards.

[0015] Step (7): Move the lower knife upwards to press against the bottom surface of the aluminum alloy plate. Step (8): The upper tool group returns to its horizontal position.

[0016] Step (9): Press the upper blade downwards.

[0017] Step (10): Reset the upper blade upwards.

[0018] Step (11): The lower blade assembly moves the fins laterally.

[0019] Step (12): Lower the knife and reset it downwards.

[0020] Step (13): The lower cutter group returns to its horizontal position.

[0021] Step (14): Repeat steps (2) to (13).

[0022] Preferably, in step (1), the distance between the large and small blades is adjusted to be equal to the thickness of the aluminum alloy plate.

[0023] Preferably, in step (1), the lower surface of the upper blade assembly is flush with the top of the fin, and the lower blade assembly is flush with the bottom of the fin.

[0024] Preferably, in step (5), the lateral movement distance of the upper blade group is equal to the sum of the fin spacing and the thickness of the aluminum alloy plate. In step (11), the lateral movement distance of the lower blade group is equal to the sum of the fin spacing and the thickness of the aluminum alloy plate.

[0025] Preferably, the width of the small blade is less than or equal to the fin spacing of the fins being processed; the width of the large blade is greater than the fin spacing of the fins being processed. The large blade is thicker to withstand the forming force, while the small blade is thinner to reduce the fin spacing.

[0026] Preferably, the stamping drive mechanism includes a transverse drive assembly, a large blade lifting drive assembly, and a small blade lifting drive assembly. Both the large blade lifting drive assembly and the small blade lifting drive assembly are mounted on the transverse drive assembly. The large blade and the small blade in the blade assembly are respectively mounted on the large blade lifting drive assembly and the small blade lifting drive assembly of their respective stamping drive mechanisms.

[0027] Preferably, the transverse drive assembly, the large blade lifting drive assembly, and the small blade lifting drive assembly all adopt a hydraulic drive structure or an electric linear module.

[0028] Preferably, the distance between the large and small knives in the same knife set can be adjusted.

[0029] Preferably, the length of the dagger is greater than the length of the scalpel; the width of the dagger is less than or equal to half the width of the scalpel.

[0030] Preferably, the large and / or small blades are provided with forming blades on their end faces. The forming blades are used for forming processes on the sides of the fins.

[0031] Preferably, the forming process involves creating an opening.

[0032] The beneficial effects of this invention are as follows: 1. This invention improves the traditional fin forming method using two equally thick blades for 180° forming on both sides to a single-sided 90° forming method using a large blade with a large thickness and a small blade with a small thickness. Based on this, the invention manufactures fins from the aluminum alloy plate being processed by stamping with a large blade while the small blades are fixed in place. During this process, the large blade bears most of the forming force. The large blade's thickness solves the stress problem for the large blade without requiring improvements in the mechanical properties of the mold material. The small blade bears less forming force, allowing for a reduction in its size and thus a smaller fin pitch while maintaining the mechanical properties of the mold. With the coordinated action of the upper and lower blade sets, fins with large thickness and small fin pitch can be stamped, solving the problem of how to produce fins for high-pressure, high-density, microchannel plate-fin heat exchangers.

[0033] 2. This invention solves the manufacturing problem of high-pressure, high-density plate-fin heat exchanger fins by adjusting the cutting tools without changing most of the original lathe structure, and has wide applicability. Attached Figure Description

[0034] Figure 1 This is a flowchart of a traditional cold stamping method for fins.

[0035] Figure 2 The flowchart shows the fin cold stamping forming method provided by the present invention. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0037] like Figure 2 As shown, a method for cold stamping high-pressure, high-density fins of a plate-fin heat exchanger is described. The stamping equipment used includes two sets of cutters and two stamping drive mechanisms (not shown in the figure). Each set of cutters includes a large cutter and a small cutter arranged side-by-side. The width of the large cutter is greater than the width of the small cutter. The width of the small cutter is less than or equal to the fin spacing of the fins being processed; the width of the large cutter is greater than the fin spacing of the fins being processed.

[0038] Two stamping drive mechanisms are used to drive two sets of cutters for lifting and traversing movements, respectively. The stamping drive mechanism includes a traversing drive assembly, a large cutter lifting drive assembly, and a small cutter lifting drive assembly. All three assemblies employ hydraulic drive structures or electric linear modules. The large and small cutter lifting drive assemblies are mounted on the traversing drive assembly. The large and small cutters in each cutter set are respectively mounted on the corresponding large and small cutter lifting drive assemblies of the stamping drive mechanism. This allows the stamping drive mechanism to drive the corresponding large and small cutters for synchronous traversing and independent lifting movements.

[0039] The two blade sets are referred to as the upper blade set and the lower blade set. The large blade and small blade in the upper blade set are called the upper large blade and upper small blade, respectively. The large blade and small blade in the lower blade set are called the lower large blade and lower small blade, respectively. The distance between the large and small blades is adjustable to accommodate aluminum alloy sheet materials of different thicknesses.

[0040] Define the horizontal plane formed by the already processed wing height as the top, and the aluminum alloy sheet to be processed as the bottom.

[0041] The method for cold stamping high-pressure, high-density fins of this plate-fin heat exchanger includes the following steps: Step (1): Place the aluminum alloy plate to be processed.

[0042] The aluminum alloy sheet to be processed is placed between the upper and lower blade groups; the conveying direction of the aluminum alloy sheet is from the large blade to the small blade in the blade group (i.e., as shown in the image). Figure 2 (From left to right). At this point, the upper and lower cutter groups are aligned, and their length direction is perpendicular to the aluminum alloy sheet being processed. The horizontal distance between the right side of the upper and lower small cutters and the previously formed fin is 0. The lower surface of the upper cutter group is flush with the top of the fin, and the lower cutter group is flush with the bottom of the fin. The spacing between the large and small cutters in the upper and lower cutter groups is adjusted to the thickness h1 of the aluminum alloy sheet being processed.

[0043] Step (2): Move the upper knife down.

[0044] The upper cutter moves downwards to the bottom, pressing against the top surface of the aluminum alloy plate being processed, serving as a support. In this step, the displacement of the upper cutter is equal to the depth of the groove in the fin.

[0045] Step (3): Press the material with a large blade.

[0046] The lower blade presses upwards until the aluminum alloy sheet being processed is lifted to contact the upper blade, causing the aluminum alloy sheet to fold into its first 90° bend. In this step, the displacement of the lower blade is equal to the depth of the groove in the fin.

[0047] Step (4): Lower the large knife to reset.

[0048] The large blade moves downwards back to its initial position.

[0049] Step (5): The upper blade assembly moves the fins.

[0050] The stamping drive mechanism corresponding to the upper blade assembly drives the upper blade assembly to move laterally, causing the fins to shift a preset distance in the conveying direction. The preset distance is equal to the sum of the fin spacing and the thickness of the aluminum alloy plate.

[0051] Step (6): Reset the small knife.

[0052] Move the upper knife upwards to its initial position.

[0053] Step (7): Move the lower knife.

[0054] The lower blade moves upward to the top, pressing against the bottom surface of the aluminum alloy plate being processed. Step (8): The upper knife assembly returns to its original position.

[0055] The stamping drive mechanism corresponding to the upper cutter group drives the upper cutter group to move laterally, so that the upper cutter group and the lower cutter group are realigned.

[0056] Step (9): Press the large blade.

[0057] The upper blade presses downwards until the aluminum alloy sheet being processed is pressed down into contact with the lower blade, causing the aluminum alloy sheet to fold into a second 90° bend. In this step, the displacement of the upper blade is equal to the depth of the groove in the fin.

[0058] Step (10): Reset the large knife.

[0059] Move the large sword upwards back to its initial position.

[0060] Step (11): The lower blade assembly moves the fins.

[0061] The stamping drive mechanism corresponding to the lower cutter group drives the lower cutter group to move laterally, causing the fins to shift a preset distance in the conveying direction. The preset distance is equal to the sum of the fin spacing and the thickness of the aluminum alloy plate.

[0062] Step (12): Lower the knife and reset it.

[0063] The smaller knife moves downwards to its initial position.

[0064] Step (13): The entire cutting assembly returns to its original position.

[0065] The stamping drive mechanism corresponding to the lower cutter group drives the lower cutter group to move laterally, so that the upper cutter group and the lower cutter group are realigned.

[0066] Step (14): Repeat steps (2) to (13) to continuously process the aluminum alloy plate into fins until the length of the fin reaches the preset value. Then cut off the connection between the fin and the aluminum alloy plate to complete the production of one fin.

[0067] In some embodiments, the end faces of the large and / or small blades are provided with forming blades. The forming blades are used to perform opening or other forming processes on the side surfaces of the fins.

[0068] In some embodiments, the forming blade can perform active telescopic movements to avoid damaging the fins during the stamping process.

[0069] The above description, in conjunction with specific examples, provides further explanation of the invention and should not be construed as limiting the specific implementation of the invention to these descriptions. For those skilled in the art, simple deductions or substitutions can be made without departing from the inventive concept, and all such modifications and substitutions should be considered within the scope of protection of this invention.

Claims

1. A method for cold stamping high-pressure, high-density fins of a plate-fin heat exchanger, characterized in that: The stamping equipment used includes two sets of upper and lower blades and their stamping drive mechanisms; the blade sets include a large blade and a small blade arranged side by side; the width of the large blade is greater than the width of the small blade; the two sets of stamping drive mechanisms are used to drive the two sets of blades to lift and move laterally respectively; the width of the small blade is less than or equal to the fin spacing of the fins being processed; the width of the large blade is greater than the fin spacing of the fins being processed. The stamping drive mechanism includes a transverse drive assembly, a large blade lifting drive assembly, and a small blade lifting drive assembly; both the large blade lifting drive assembly and the small blade lifting drive assembly are mounted on the transverse drive assembly. The large and small blades in the blade assembly are respectively mounted on the large blade lifting drive assembly and the small blade lifting drive assembly of the corresponding stamping drive mechanism; The method for cold stamping high-pressure, high-density fins of this plate-fin heat exchanger includes the following steps: Step (1): Place the aluminum alloy plate to be processed between the upper and lower blade groups that are aligned with each other; in step (1), the distance between the large blade and the small blade is adjusted to be equal to the thickness of the aluminum alloy plate; in step (1), the lower surface of the upper blade group is flush with the top of the fin, and the lower blade group is flush with the bottom of the fin; the conveying direction of the aluminum alloy plate to be processed is from the large blade to the small blade in the blade group. Step (2): Move the upper knife down to press against the top surface of the aluminum alloy plate; Step (3): Press the large blade upwards; Step (4): Lower the large blade and reset it; Step (5): The upper blade assembly moves the fins laterally; in step (5), the lateral movement distance of the upper blade assembly is equal to the sum of the fin spacing and the thickness of the aluminum alloy plate; Step (6): Reset the upper knife upwards; Step (7): Move the lower knife upwards to press against the bottom surface of the aluminum alloy plate. Step (8): The upper tool assembly returns to its horizontal position; Step (9): Press the upper blade downwards; Step (10): Reset the upper blade upwards; Step (11): The lower blade assembly moves the fins laterally; in step (11), the lateral movement distance of the lower blade assembly is equal to the sum of the fin spacing and the thickness of the aluminum alloy plate; Step (12): Lower the knife and reset it downwards; Step (13): The lower cutter group returns to its horizontal position; Step (14): Repeat steps (2) to (13).

2. The method for cold stamping high-pressure, high-density fins of a plate-fin heat exchanger according to claim 1, characterized in that: The transverse drive assembly, the large blade lifting drive assembly, and the small blade lifting drive assembly all adopt a hydraulic drive structure or an electric linear module.

3. The method for cold stamping high-pressure, high-density fins of a plate-fin heat exchanger according to claim 1, characterized in that: Within the same set of knives, the distance between the large and small knives can be adjusted.

4. The method for cold stamping high-pressure, high-density fins of a plate-fin heat exchanger according to claim 1, characterized in that: The length of the dagger is greater than that of the scalpel; the width of the dagger is less than or equal to half the width of the scalpel.

5. The method for cold stamping high-pressure, high-density fins of a plate-fin heat exchanger according to claim 1, characterized in that: The end face of the large and / or small blades is provided with forming blades; the forming blades are used for forming the fins.

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