A high-pressure narrow-channel heat exchanger

Abstract

This utility model relates to the field of high-efficiency heat exchanger manufacturing technology, specifically a high-pressure narrow-channel heat exchanger, including a base plate with several channels evenly distributed on the base plate, with stiffeners between adjacent channels and bosses at the top of the stiffeners; and a cover plate, which is placed on top of the base plate, with a groove at the bottom of the cover plate that mates with the bosses, and the bosses and grooves coupling to form a "T"-shaped double-shear brazing seam structure, with a brazing filler layer in the "T"-shaped double-shear brazing seam structure, the thickness of which is the height of the bosses; the top of the base plate and the bottom of the cover plate are fixedly connected; this utility model high-pressure narrow-channel heat exchanger increases the weld seam bearing area, forming a double-shear stress surface, significantly improving the heat exchanger's load-bearing capacity and fatigue life, meeting the requirements of high pressure and long service life; the precise matching of the brazing filler layer thickness and the boss height avoids overflow clogging of the channels.

Description

Technical Field

[0001] This utility model relates to the field of high-efficiency heat exchanger manufacturing technology, specifically a high-pressure narrow-channel heat exchanger. Background Technology

[0002] Narrow-channel heat exchangers achieve efficient heat exchange by machining microchannels in thin plates, offering advantages such as compact structure and high heat transfer coefficient. Existing technologies typically employ a planar lap brazing process, directly brazing the cover plate to the top surface of the channel wall. However, this structure has the following problems:

[0003] First, the bearing capacity of the brazed joint is insufficient: the planar lap brazed joint only forms a single shear surface. Under high pressure conditions (such as 3-7MPa), the shear strength is difficult to meet the requirements, and delamination or leakage is likely to occur.

[0004] Secondly, the filling of the brazing filler metal is difficult to control. During the vacuum brazing process, the melted brazing filler metal is prone to overflow due to gravity or capillary action, which can block the channels.

[0005] Therefore, it is necessary to design a high-pressure narrow-channel heat exchanger to improve the above problems. Summary of the Invention

[0006] To address the problems of existing technologies, this utility model provides a high-pressure narrow-channel heat exchanger, including a base plate on which several channels are evenly distributed. Ribs are provided between adjacent channels, and a boss is provided at the top of the ribs.

[0007] The cover plate is provided on the top of the base plate. The bottom of the cover plate is provided with a groove that mates with the boss. The boss and the groove are coupled to form a "T"-shaped double-shear brazing seam structure. A brazing filler layer is provided in the "T"-shaped double-shear brazing seam structure. The thickness of the brazing filler layer is the height of the boss.

[0008] Furthermore, the top of the base plate and the bottom of the cover plate are fixed together by vacuum brazing.

[0009] Furthermore, the solder layer is a NiCrSiB-based solder foil.

[0010] Furthermore, the thickness of the stiffening plate is 1.5-2mm.

[0011] Furthermore, the height of the boss is 0.3-0.6mm and the width is 1.0-1.5mm.

[0012] Furthermore, both the cover plate and the bottom plate are stainless steel rectangular plates, and the thickness of the bottom plate is 2-4mm.

[0013] Furthermore, the channel has a rectangular cross-section, a width of 7-10 mm, and a depth of 2-5 mm.

[0014] A heat exchange device comprising the aforementioned high-pressure narrow-channel heat exchanger;

[0015] The beneficial effects of this utility model are:

[0016] This application describes a high-pressure narrow-channel heat exchanger. A boss is installed on the top of the stiffener between adjacent channels on the base plate. The boss on the base plate couples with the groove on the cover plate to form a T-shaped double-shear brazed seam structure. The brazing filler layer is located within this T-shaped structure, increasing the weld bearing area and creating a double-shear stress surface. Compared to traditional planar lap joint structures, the shear area is increased by approximately 175%, significantly improving the heat exchanger's load-bearing capacity and fatigue life, meeting the requirements for high pressure and long service life. Precise matching of the brazing filler layer thickness with the boss height prevents overflow and channel blockage. Stable control of the vacuum brazing process prevents melt collapse and channel blockage. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the base plate structure of the heat exchanger of this utility model;

[0018] Figure 2 This is a schematic diagram of the cover plate structure of the heat exchanger of this utility model;

[0019] Figure 3 This is a sectional view AA of the heat exchanger base plate of this utility model;

[0020] Figure 4 A partial schematic diagram of part B on the base plate of this utility model.

[0021] Figure label:

[0022] In the diagram: 1-base plate, 2-channel, 3-boob, 4-cover plate. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figure 1-4 This utility model provides a high-pressure narrow-channel heat exchanger, comprising:

[0025] The base plate 1 has several channels 2 evenly distributed on it, and stiffeners are provided between adjacent channels. A boss 3 is provided at the top of the stiffener.

[0026] Cover plate 4 is provided on the top of the base plate 1. The bottom of the cover plate 4 is provided with a groove that mates with the boss 3. The boss 3 and the groove are coupled to form a "T"-shaped double shear brazing seam structure. A brazing filler layer is provided in the "T"-shaped double shear brazing seam structure. The thickness of the brazing filler layer is the height of the boss 3. The height of the boss 3 directly limits the thickness of the brazing seam, preventing brazing filler overflow and ensuring unobstructed passage.

[0027] Furthermore, the top of the base plate 1 and the bottom of the cover plate 4 are fixed by vacuum brazing;

[0028] It should be noted that the high-pressure narrow-channel heat exchanger includes a base plate 1, made of 2-4mm thick 304 or 316L stainless steel plate. Multiple rectangular channels 2 are milled on the base plate 1, with a channel wall thickness of 1.5-2mm. The width of the channel 2 is 7-10mm, and the depth of the channel 2 is 2-5mm. A boss 3 is machined on the top of the stiffener between adjacent channels 2, with a height of 0.3-0.6mm and a width of 1.0-1.5mm. A cover plate 4, made of the same stainless steel plate as the base plate 1, covers the base plate 1. A brazing layer is set between the top surface of the boss 3 and the bottom surface of the cover plate 4. The brazing layer is a NiCrSiB series brazing foil with a thickness of 40-60μm. After vacuum brazing, the brazing layer is located in the groove coupling of the boss 3 and the cover plate 4 to form a "T"-shaped double-shear brazing seam structure. The thickness of the brazing seam is equal to the height of the boss 3, and the shear strength of the brazed joint is ≥320MPa.

[0029] Brazing process parameters: Vacuum degree ≤ 1×10 -3 Pa; heating rate is 8-12℃ / min; brazing temperature is 1080±10℃; holding time is 10-15min; hot press surface pressure is 10-15kPa; cooling method is furnace cooling to below 200℃ before unloading.

[0030] Furthermore, the solder layer is a NiCrSiB-based solder foil with a thickness of 40-60 μm;

[0031] Furthermore, the thickness of the stiffening plate is 1.5-2mm;

[0032] Furthermore, the height of the boss 3 is 0.3-0.6mm, and the width is 1.0-1.5mm;

[0033] Furthermore, both the cover plate 4 and the bottom plate 1 are stainless steel rectangular plates, and the thickness of the bottom plate 1 is 2-4 mm;

[0034] Furthermore, the cross-section of the channel 2 is rectangular, the width of the channel 2 is 7-10mm, and the depth of the channel 2 is 2-5mm;

[0035] Furthermore, a tungsten inert gas protective layer is provided on the contact surfaces of the four edges of the base plate 1 and the cover plate 4 to seal the edges of the base plate 1 and the cover plate 4.

[0036] It should be noted that the tungsten inert gas protective layer is formed by TIG continuous welding. The four sides of the base plate 1 and the cover plate 4 are sealed by TIG continuous welding. TIG (Tungsten Inert Gas Continuous Welding)

[0037] A heat exchange device comprising the aforementioned high-pressure narrow-channel heat exchanger;

[0038] Example 1, Heat Exchanger Parameters

[0039] The dimensions of both the base plate 1 and the cover plate 4 are: 1500mm × 350mm × 3mm (304L stainless steel);

[0040] Channel 2 quantity: 30 channels; Channel size: 9mm × 3mm;

[0041] The height of boss 3 is 0.35mm, and the width of boss 3 is 1.2mm.

[0042] The solder layer is a 50μm thick NiCrSiB solder foil;

[0043] Performance testing: The brazed joint shear strength is 368-377 MPa; no leakage was observed during the 7 MPa hydrostatic test; the flatness is 0.35 mm / m.

[0044] Example 2, heat exchanger parameters: The dimensions of both the base plate 1 and the cover plate 4 are 1500mm×500mm×3mm (316L stainless steel);

[0045] Channel 2 quantity: 40 channels;

[0046] Channel 2 dimensions: 8mm × 2.5mm;

[0047] The height of boss 3 is 0.5 mm; the width of boss 3 is 1.5 mm; the solder layer is a 60 μm thick NiCrSiB solder foil.

[0048] Applicable operating conditions for heat exchanger: steam side pressure 7MPa;

[0049] Number of cycles: 10 pressure cycles 4 Leakage rate: <1×10 -9 Pa·m 3 / s;

[0050] It is worth noting that the formation of the double shear force depends on: 1. the coupling of the boss and the groove to form a T-shaped double shear brazing seam structure; 2. the precise matching of the thickness of the brazing filler layer and the height of the boss; 3. the stable control of the vacuum brazing process. The combination of these three factors significantly improves the shear area and load-bearing capacity, meeting the requirements of high pressure (7MPa) and long service life (10 MPa). 4 (Sub-cycle) demand.

[0051] The high-pressure narrow-channel heat exchanger described in this application features a boss on the top of the stiffener between adjacent channels on the base plate. The boss on the base plate is coupled with the groove on the cover plate to form a T-shaped double-shear brazing structure. The brazing filler layer is located in the T-shaped double-shear brazing structure, so that the brazing filler joint surface between the side wall of the boss and the side wall of the groove on the cover plate forms a vertical shear surface, and the brazing filler joint surface between the top surface of the boss and the bottom surface of the groove on the cover plate forms a horizontal shear surface. This increases the weld bearing area and forms a double shear stress surface. When the heat exchanger is subjected to internal pressure, the shear force acts on two vertical surfaces simultaneously, significantly dispersing the load.

[0052] Furthermore, the thickness of the solder layer (40-60μm) and the height of the boss (0.3-0.6mm) are precisely matched to ensure that the solder fills only within the T-shaped double-shear brazing seam structure, preventing overflow and blockage of the channel;

[0053] Furthermore, the stable control of vacuum brazing is achieved. NiCrSiB-based brazing foil uniformly fills the gap between the boss and the groove at high temperature, forming a continuous double-shear brazing seam. The boss width (1.0-1.5mm) directly determines the transverse dimension of the shear surface. Compared to traditional single-plane overlap, the T-shaped double-shear brazing seam structure increases the shear area by approximately 175%. The double shear surfaces share the load, avoiding single-point stress concentration, resulting in a brazed joint shear strength ≥320MPa. The hot press block and boss provide coordinated support during brazing. During brazing, the hot press block applies 10-15kPa surface pressure, working together with the boss to support the cover plate, suppressing deformation during the brazing process and effectively inhibiting cover plate warping, ensuring the geometric accuracy of the double shear surfaces. The finished heat exchanger has a flatness ≤0.4mm / m and can withstand 7MPa pressure cycles for 10... 4 No leakage was observed.

[0054] Tested using the example (7MPa water pressure, 10...) 4 (Second cycle) Proof: 1. The double shear surface design makes the leakage rate less than 1×10⁻⁶. -9 Pa·m 3 / s, far exceeding traditional structures; 2. Stability of vacuum brazing: The thickness of the brazing seam is precisely controlled by the height of the boss (e.g., 0.35mm or 0.5mm), avoiding overflow and clogging of the channel, ensuring structural integrity under long-term circulation; significantly improving the load-bearing capacity and fatigue life of the heat exchanger, meeting the requirements of high pressure (7MPa) and long service life (10 4 (Sub-cycle) demand.

[0055] The high-pressure narrow-channel heat exchanger described in this application features a boss on the top of the stiffener between adjacent channels on the base plate. This boss, coupled with the groove on the cover plate, forms a T-shaped double-shear brazed joint structure. The brazing filler metal layer is located within this structure, increasing the weld bearing area and creating a double-shear stress surface. Compared to traditional planar lap joint structures, this increases the shear area by approximately 175%, and the brazed joint shear strength is ≥320MPa. This significantly improves the heat exchanger's load-bearing capacity and fatigue life, meeting the requirements for high pressure and long service life. Precise matching of the brazing filler metal layer thickness with the boss height prevents overflow and channel blockage. Stable control of the vacuum brazing process also prevents melt collapse and channel blockage.

[0056] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A high-pressure narrow-channel heat exchanger, characterized in that, Includes a base plate, on which several channels are evenly distributed, with stiffening plates between adjacent channels, and a boss at the top of each stiffening plate; A cover plate is provided on the top of the base plate. The bottom of the cover plate is provided with a groove that mates with the boss. The boss and the groove are coupled to form a "T"-shaped double-shear brazing seam structure. A brazing filler layer is provided in the "T"-shaped double-shear brazing seam structure. The thickness of the brazing filler layer is the height of the boss.

2. The high-pressure narrow-channel heat exchanger according to claim 1, characterized in that, The top of the base plate and the bottom of the cover plate are fixed by vacuum brazing.

3. A high-pressure narrow-channel heat exchanger according to claim 1, characterized in that, The solder layer is a NiCrSiB-based solder foil.

4. A high-pressure narrow-channel heat exchanger according to claim 1, characterized in that, The thickness of the stiffener is 1.5-2mm.

5. A high-pressure narrow-channel heat exchanger according to claim 1, characterized in that, The boss has a height of 0.3-0.6mm and a width of 1.0-1.5mm.

6. A high-pressure narrow-channel heat exchanger according to claim 1, characterized in that, Both the cover plate and the base plate are stainless steel rectangular plates, and the thickness of the base plate is 2-4mm.

7. A high-pressure narrow-channel heat exchanger according to claim 1, characterized in that, The channel has a rectangular cross-section, a width of 7-10 mm, and a depth of 2-5 mm.

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