Brazing type plate heat exchanger

Abstract

The utility model provides a brazing type plate heat exchanger, which relates to the technical field of heat exchangers, and comprises a heat exchanger main body and plate sheets, a plurality of plate sheets are arranged in the heat exchanger main body, corner holes are arranged at four corners of each plate sheet, a flow guide plate is arranged near the edge of each corner hole, and the flow guide plates are arranged in the heat exchanger main body. Hexagonal micro pits are formed in a brazing area of the sheet bar. Corrugation angles on the plate sheets are gradually reduced from 60 degrees of an inlet to the center, and are matched with spiral corrugations with opposite rotation directions of adjacent plate sheets to form three-dimensional vortexes, enhance turbulence effects, reduce low-speed flow areas and improve heat exchange efficiency, and meanwhile, the semi-ellipsoid flow guide bosses form transverse secondary flows in the central areas of the plate sheets, destroy heat boundary layers and strengthen heat transfer, so that the heat exchange efficiency is improved. The heat exchange coefficient of a low-flow-rate area is improved.

Description

Technical Field

[0001] This utility model relates to the field of heat exchanger technology, and in particular to a brazed plate heat exchanger. Background Technology

[0002] Brazed plate heat exchangers are a new type of high-efficiency heat exchanger made by brazing a series of metal plates with a certain corrugated shape. Thin rectangular channels are formed between the plates, and heat is exchanged through the plates. Compared with conventional shell and tube heat exchangers, under the same flow resistance and pump power consumption, its heat transfer coefficient is much higher, and it has the trend of replacing shell and tube heat exchangers in the applicable range.

[0003] In traditional plate heat exchanger designs, the flow channel design of the corrugated plates is relatively simple, resulting in uneven fluid distribution and the formation of low-velocity flow zones in certain areas, thus reducing overall heat exchange efficiency. This means that the equipment cannot fully utilize its heat exchange capacity during actual operation, affecting system performance and efficiency. Another significant problem with brazed plate heat exchangers is the stress concentration at the brazed interface. During long-term thermal cycling, microcracks are prone to form at the brazed joints, which not only reduces the heat exchanger's sealing performance but also shortens its service life. This localized stress concentration poses a challenge to the reliability and stability of the equipment, especially in industrial environments where frequent switching of operating temperature and pressure is required. Furthermore, the flow distribution in the corner areas is not ideal, and the utilization rate of some flow channels is low, leading to increased pressure drop losses. This inefficient design not only increases energy consumption but also increases the load on the pumping device, further affecting the overall performance and economy of the system. Therefore, we propose a brazed plate heat exchanger. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of existing technologies. In traditional plate heat exchanger designs, the flow channel design of the corrugated plates is relatively simple, resulting in uneven fluid distribution and the formation of low-speed flow zones in certain areas, thus reducing overall heat exchange efficiency. This means that the equipment cannot fully utilize its heat exchange capacity during actual operation, thereby affecting the system's performance and efficiency. Another significant problem with brazed plate heat exchangers is the stress concentration at the brazed interface. During long-term thermal cycling, microcracks are prone to form at the brazed joint, which not only reduces the heat exchanger's sealing performance but also shortens its service life. This localized stress concentration poses a challenge to the reliability and stability of the equipment, especially in industrial environments where frequent switching of operating temperature and pressure is required. Furthermore, the flow distribution in the corner areas is not ideal, and the utilization rate of some flow channels is low, leading to increased pressure drop losses. This inefficient design not only increases energy consumption but also increases the load on the pumping device, further affecting the overall performance and economy of the system.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A brazed plate heat exchanger includes a heat exchanger body and plates. Several plates are installed inside the heat exchanger body. Corner holes are provided at the four corners of each plate. A guide plate is installed near the edge of each corner hole. Hexagonal micro-recesses are provided in the brazing area of ​​each plate.

[0007] Furthermore, the plate is provided with corrugations, and the corrugations have a spirally expanding structure. The inlet angle of the corrugations is 60°, and the inlet angle gradually decreases towards the center of the plate.

[0008] Furthermore, the spiral corrugations of adjacent plates rotate in opposite directions, and a flow guide protrusion is provided at the center of each plate. The flow guide protrusion is a semi-ellipsoid, and the flow guide protrusions of adjacent plates are staggered.

[0009] Furthermore, a spiral guide groove is machined on the inner wall of the corner hole, and the pitch of the spiral guide groove is 5mm.

[0010] Furthermore, the root of the guide plate is installed at a distance of 5-10mm from the edge of the corner hole via laser micro-welding points, and the head of the guide plate is suspended and can swing.

[0011] Furthermore, a semi-circular notch is provided at the root of the guide plate, and the minimum gap between the root of the guide plate and the outer wall of the inlet pipe of the heat exchanger body is greater than 2mm.

[0012] Furthermore, the back of the guide plate is provided with several arc-shaped microribs, the guide plate is initially parallel to the plate, and the opening and closing angle of the guide plate is 0°-30°.

[0013] Furthermore, the hexagonal micro-pits are honeycomb-shaped, and a brazing filler groove is pre-placed inside the hexagonal micro-pits, with a depth of 0.1 mm. The edges of the hexagonal micro-pits are transitioned by a slope.

[0014] Compared with the prior art, the beneficial effects of this utility model are:

[0015] 1. The corrugation angle on the plate gradually decreases from 60° at the inlet to the center. Combined with the spiral corrugations of adjacent plates with opposite rotation directions, a three-dimensional vortex is formed, which enhances the turbulence effect, reduces the low-speed flow zone, and improves the heat transfer efficiency. At the same time, the semi-ellipsoidal flow guide protrusion forms a transverse secondary flow in the central region of the plate, which breaks the thermal boundary layer, enhances heat transfer, and improves the heat transfer coefficient in the low-velocity region.

[0016] 2. The brazing area of ​​the plate has a hexagonal recess with a pre-set brazing filler groove with a depth of 0.1mm, which increases the brazing contact area by 25%, forms a mechanical interlocking structure, improves shear strength by 30%, and significantly reduces the risk of microcracks caused by thermal cycling. At the same time, the edge of the hexagonal recess adopts a 45° slope design to alleviate stress concentration and extend the fatigue life of the brazed joint.

[0017] 3. The flexible guide vane automatically adjusts the diversion ratio according to the flow rate, increasing the flow channel utilization rate from 80% to 98%. In addition, the guide vane avoids gaps to ensure no interference with the pipe connection, while reducing corner pressure loss by 15%. The micro-ribs on the back of the guide vane provide elastic restoring force to adapt to changing operating conditions and reduce pumping energy consumption by 10%. Attached Figure Description

[0018] Figure 1 This invention provides an overall structural design for a brazed plate heat exchanger.

[0019] Figure 2 A schematic diagram of the plate structure of a brazed plate heat exchanger provided by this utility model;

[0020] Figure 3 A schematic diagram of the arc-shaped micro-rib structure on the back of the guide plate of a brazed plate heat exchanger provided by this utility model;

[0021] Figure 4 A schematic diagram of a hexagonal micro-recessed structure for a brazed plate heat exchanger provided by this utility model.

[0022] Legend: 1. Heat exchanger body; 2. Plate; 201. Corner hole; 202. Flow guide plate; 203. Hexagonal micro-recess; 204. Corrugation; 205. Flow guide boss; 206. Spiral flow guide groove; 207. Arc-shaped micro-rib. Detailed Implementation

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

[0024] To facilitate understanding of this utility model, a more comprehensive description of this utility model will be provided below with reference to relevant embodiments, and several embodiments of this utility model will be given. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of this utility model more thorough and complete.

[0025] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. Example 1

[0027] like Figure 1-4 As shown, this utility model provides a technical solution: a brazed plate heat exchanger, including a heat exchanger body 1 and plates 2. Several plates 2 are installed inside the heat exchanger body 1. Corner holes 201 are opened at the four corners of the plates 2. A guide plate 202 is installed near the edge of each corner hole 201. The guide plate 202 dynamically adjusts the flow distribution ratio, increasing the flow channel utilization rate from 80% to 98%. Hexagonal micro-recesses 203 are opened in the brazing area of ​​the plates 2. The brazing area of ​​the plates 2 refers to the surface area where two adjacent plates 2 are directly bonded and fused together by brazing material after assembly. In this utility model, the brazing area of ​​the hexagonal micro-recesses 203 is the annular area around the corner holes 201. The hexagonal micro-recesses 203 increase the brazing contact area and improve the shear strength. Example 2

[0028] like Figure 1-4 As shown, the plate 2 is provided with corrugations 204, and the corrugations 204 are spirally expanding structures. These corrugations 204 reference the spiral flow principle of a spiral baffle heat exchanger, but are miniaturized and applied to the plate corrugations. The inlet angle of the corrugations 204 is 60°, and the angle at the inlet gradually decreases towards the center of the plate 2. The spiral corrugations 204 of adjacent plates 2 rotate in opposite directions. A flow guide boss 205 is provided at the center of the plate 2. The flow guide boss 205 is a semi-ellipsoid, and the flow guide boss 205 guides the flow... The linear profile reduces flow resistance. The guide bosses 205 of adjacent plates 2 are staggered and formed by brazing to create staggered obstructions. When the fluid passes through the guide bosses 205, a transverse secondary flow is generated, which promotes the mixing of hot and cold fluids. The top of the guide bosses 205 is brazed with the opposite plate 2 to form a micro support point, which enhances the compressive strength of the plate 2. The inner wall of the corner hole 201 is machined with a spiral guide groove 206. The pitch of the spiral guide groove 206 is 5mm. The spiral guide groove 206 pre-swirls the fluid to improve the uniformity of distribution.

[0029] The root of the guide plate 202 is installed 5-10mm from the edge of the corner hole 201 via laser micro-welding. The head of the guide plate 202 is suspended and can swing. A semi-circular notch is opened at the root of the guide plate 202. The guide plate 202 is made of ultra-thin nickel-titanium alloy sheet with a thickness of 0.2mm, which has both elasticity and corrosion resistance. The minimum gap between the root of the guide plate 202 and the outer wall of the nozzle of the heat exchanger body 1 is greater than 2mm. Several [unclear text - possibly related to a specific feature or feature] are provided on the back of the guide plate 202. The arc-shaped microrib 207 ensures that the flow diversion effect is maintained even at low flow rates. The guide plate 202 is initially parallel to the plate 2. The opening and closing angle of the guide plate 202 is 0°-30°. When there is no fluid, the guide plate 202 is parallel to the plate 2 and does not protrude from the corner hole 201. When there is fluid, the fluid pressure pushes the guide plate 202 to unfold, with a maximum angle of 30°, forming a flow guiding slope. The unfolding angle of the guide plate is large at high pressure and relies on elastic reset at low pressure.

[0030] The hexagonal micro-pit 203 is honeycomb-shaped and has a pre-set brazing filler groove with a depth of 0.1 mm. The brazing filler groove forms a mechanical anchor point during brazing. The edge of the hexagonal micro-pit 203 is sloped to reduce stress concentration.

[0031] The working process of this utility model is as follows: When using a brazed plate heat exchanger, the fluid first enters the corner hole 201 through the connecting pipe. The hot and cold fluids flow into the corner hole 201 from the connecting pipes on both sides of the heat exchanger. The spiral guide groove 206 on the inner wall of the corner hole 201 causes the fluid to rotate, which initially improves the uniformity of distribution.

[0032] Dynamic adjustment of the guide vane 202 at the edge of the corner hole 201:

[0033] 1) When there is no fluid or the flow rate is low: the guide plate 202 remains parallel to the plate 2 and does not obstruct the flow;

[0034] 2) At medium to high flow rates: the fluid pressure pushes the guide plate 202 to unfold, forming a guide slope, which evenly distributes the flow to each channel, increasing the channel utilization rate from 80% to 98%;

[0035] The spiral corrugations 204 of adjacent plates 2 inside the heat exchanger body 1 rotate in opposite directions, forcing the fluid to generate cross rotation. The inlet angle of the corrugations 204 is 60°, gradually narrowing towards the center to match the fluid expansion and reduce dead zones. At the same time, the semi-ellipsoidal bosses are staggered and formed into micro support points after brazing. When the fluid passes through, a transverse secondary flow is generated, which promotes the mixing of hot and cold fluids and increases the heat transfer coefficient by 15-20%.

[0036] The fluid flows towards the outlet along the spiral corrugations 204. The gradually expanding flow channel reduces the outlet velocity and reduces backflow losses. When the flow rate decreases, the guide plate 202 is elastically reset by the arc-shaped micro-ribs 207 on the back side to avoid low-pressure stagnation.

[0037] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A brazed plate heat exchanger, comprising a heat exchanger body (1) and plates (2), wherein a plurality of plates (2) are installed within the heat exchanger body (1), characterized in that: Corner holes (201) are provided at the four corners of the plate (2), and a guide plate (202) is installed near the edge of each corner hole (201). Hexagonal micro-pits (203) are provided in the brazing area of ​​the plate (2).

2. The brazed plate heat exchanger according to claim 1, characterized in that: The plate (2) is provided with corrugations (204), and the corrugations (204) are spirally expanding structures. The inlet angle of the corrugations (204) is 60°, and the inlet angle gradually shrinks towards the center of the plate (2).

3. The brazed plate heat exchanger according to claim 1, characterized in that: The spiral corrugations (204) of adjacent plates (2) rotate in opposite directions. A flow guide boss (205) is provided at the center of the plate (2). The flow guide boss (205) is a semi-ellipsoid. The flow guide bosses (205) of adjacent plates (2) are staggered.

4. A brazed plate heat exchanger according to claim 1, characterized in that: A spiral guide groove (206) is machined on the inner wall of the corner hole (201), and the pitch of the spiral guide groove (206) is 5mm.

5. A brazed plate heat exchanger according to claim 1, characterized in that: The root of the guide plate (202) is installed at a distance of 5-10 mm from the edge of the corner hole (201) by laser micro-welding points, and the head of the guide plate (202) is suspended and can swing.

6. A brazed plate heat exchanger according to claim 1, characterized in that: The root of the guide plate (202) has a semi-circular notch, and the minimum gap between the root of the guide plate (202) and the outer wall of the nozzle of the heat exchanger body (1) is greater than 2mm.

7. A brazed plate heat exchanger according to claim 1, characterized in that: The back of the guide plate (202) is provided with several arc-shaped micro ribs (207). The guide plate (202) is initially parallel to the plate (2). The opening and closing angle of the guide plate (202) is 0°-30°.

8. A brazed plate heat exchanger according to claim 1, characterized in that: The hexagonal micro-pit (203) is honeycomb-shaped, and a brazing filler groove is pre-set in the hexagonal micro-pit (203), with a depth of 0.1 mm. The edge of the hexagonal micro-pit (203) is transitioned by a slope.

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