Plate heat exchanger

Abstract

The utility model discloses a plate heat exchanger, belongs to the field of air pre-heaters, solves the problem that in the prior art, plates of a plate heat exchanger are prone to damage when heat exchange is conducted in dust-containing flue gas, and adopts the technical scheme that the plate heat exchanger comprises a heat exchange plate, and the heat exchange plate is formed by welding and fixing two thin plates through a plurality of welding parts; the non-welded portions of the thin plates are far away from each other to form a gas flowing cavity, the edges, close to the smoke flowing-in side, of the two thin plates of the heat exchange plate are first ends, the first ends are fixed through welding parts, guiding pieces are installed at the first ends, and the thickness of the guiding pieces is larger than that of the two thin plates. The dust-containing flue gas heat exchanger is mainly used for realizing heat exchange in dust-containing flue gas at low cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of air preheater, in particular to a plate heat exchanger. BACKGROUND

[0002] The plate heat exchanger is a kind of high-efficiency heat exchange equipment, which is mainly composed of a plurality of metal sheets (such as stainless steel plates, titanium plates, etc.) with specific corrugated shape tightly stacked. Its working principle is to make hot fluid and cold fluid flow in adjacent narrow channels separated by metal sheets, and the fluid flow direction can be reversed or forward (the heat exchange efficiency is higher when reversed). Heat will be conducted from hot fluid with high temperature to cold fluid through thin metal sheets, and the corrugated design of metal sheets makes the fluid form turbulent flow, increases the contact area and heat transfer coefficient, and greatly improves the heat exchange efficiency.

[0003] In some working scenarios, high-temperature dust-containing exhaust gas is discharged during processing. When exchanging heat in such dust-containing flue gas, due to the existence of variable diameter, turning section at the inlet of the heat exchanger, and the decrease of flow area when the flue gas enters the heat exchanger, the flue gas entering the heat exchanger has conditions such as vortex and turbulence, which aggravates the wear of the heat exchange plates, especially the parts where the cold medium flows are expanded during processing, so that the wall thickness of the plates at this part is thinned, especially the expansion part and the welding part of the plates become weak due to deformation, and when heat exchange is carried out, the dust particles in the flue gas will directly impact on this part, thereby causing the plate to break and leak the cold medium in the plate. Generally, the method to overcome is to increase the thickness of the plate, which further increases the difficulty of plate processing, thereby increasing the processing cost and material cost of the plate, and due to the increase of the thickness of the plate, the heat exchange efficiency of the flue gas is reduced. SUMMARY

[0004] In order to overcome the defect that the plate heat exchanger in the prior art is easy to break when exchanging heat in dust-containing flue gas, the present application provides a plate heat exchanger which can realize low-cost heat exchange in dust-containing flue gas.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: a plate heat exchanger, comprising a heat exchange plate, the heat exchange plate is fixed by welding a plurality of welding parts on two thin plates, the parts of the thin plates not welded are away from each other to form a gas flow cavity, the edges of the two thin plates of the heat exchange plate close to the flue gas inflow side are first ends, the first ends are fixed by welding parts, and the first ends are provided with a shielding piece for shielding the welding parts on the first ends.

[0006] The application has the following advantages: in the complex working condition of dust-containing flue gas, the flue gas entering the heat exchanger is prone to vortex and turbulence, and the shielding piece can partially shield the flue gas entering the heat exchanger, thereby avoiding the direct impact of dust particles in the flue gas on the parts of the plate sheet that are prone to damage, thereby significantly reducing the wear of the heat exchange plate sheet, so that the service life of the plate heat exchanger in the dust-containing flue gas can be prolonged without increasing the thickness of the plate sheet, and when the heat exchanger is used for a long time, the shielding piece is damaged first, and then the shielding piece is removed and replaced with a new shielding piece or repaired by welding, and then the shielding piece is reloaded on the heat exchange plate, thereby reducing the use cost of the heat exchange plate, and since the shielding piece is installed at the edge of the two thin plates, the welding part of the edge can be protected from being impacted by the dust-containing flue gas, thereby preventing the welding part from cracking, and the service life of the heat exchange plate can be prolonged without affecting the heat dissipation efficiency of the heat exchange plate.

[0007] Further, the shielding piece wraps the welding part on the first end to shield the welding part on the first end close to the flow cavity.

[0008] According to the foregoing technical scheme, since the first end close to the flow cavity is deformed from a thin plate, the windward curvature at the junction of the first end close to the flow cavity and the flow cavity is also the largest, and therefore the damage caused by the impact of dust particles is the largest, so that the welding part on the first end is wrapped by the shielding piece, the shielding piece shields the welding part, the direct impact of dust particles is prevented, and the service life of the welding part is prolonged.

[0009] Further, the maximum thickness of the shielding piece is greater than or equal to the maximum thickness of the heat exchange plate.

[0010] The shielding piece with a wide enough width can better regulate the flow path of the flue gas, and since the width covers a wide range, the flue gas can reduce the change in the flow cross section of the flue gas entering the heat exchanger, thereby ensuring the uniformity of the flue gas flow and reducing the wear of the heat exchange plate sheet by the dust-containing flue gas.

[0011] Further, the shielding piece is provided with a clamping groove adapted to the thickness of the welding part on the first end.

[0012] According to the foregoing technical scheme, the clamping groove adapted to the thickness of the edge of the heat exchange plate is used as the mounting part, so that the shielding piece is more convenient to install on the heat exchange plate, and at the same time, the clamping groove is closely fitted with the edge of the heat exchange plate, thereby providing stable and reliable connection, effectively preventing the shielding piece from being displaced or falling off due to vibration or flue gas impact during operation, and ensuring that the shielding piece is always in the correct working position and continuously plays a guiding role for the flue gas and a protective role for the plate sheet.

[0013] Further, the cross-sectional shape of the shielding piece is inverted U-shaped, so that the opening of the clamping groove is open downward, and the arc-shaped section of the shielding piece faces the direction of the flue gas flow.

[0014] With the foregoing technical solution, the cross-sectional shape of the shielding piece is inverted U-shaped, so that it can wrap the key parts of the edge of the heat exchange plate from multiple directions. Moreover, the opening of the inverted U-shaped shielding piece serves as a clamping groove, which is simple in structure and easy to operate, and can be easily clamped on the edge of the heat exchange plate to achieve quick and convenient installation. When the flue gas enters the heat exchanger, it can be gradually guided by the arc-shaped section, reducing the turbulence and vortex caused by sharp turning, so that the flue gas is uniformly dispersed and flows over the heat exchange plate at a more reasonable speed. This not only helps to reduce the direct impact of dust particles on the plate, but also improves the heat exchange efficiency, making the heat transfer between the cold and hot fluids more sufficient and uniform.

[0015] Further, the shielding piece is provided with a guide portion, which is inclined to the direction of the flue gas flow, so that the flue gas is guided by the guide portion to be away from the heat exchange plate.

[0016] With the foregoing technical solution, the design of the guide portion inclined to the direction of the flue gas flow can change the flow path of the flue gas, actively guiding the flue gas away from the heat exchange plate, thereby more effectively avoiding direct contact between dust particles and the heat exchange plate, especially its fragile parts, reducing the risk of wear and damage.

[0017] Further, the cross-sectional shape of the shielding piece is h-shaped composed of a short arm and a long arm, the opening of the shielding piece is open downward, the opening of the shielding piece is adapted to the thickness of the welding portion on the first end, and the connection between the short arm and the long arm of the shielding piece is a guide portion.

[0018] With the foregoing technical solution, the opening of the h-shaped shielding piece serves as a mounting portion, which can be clamped on the edge of the heat exchange plate like a clip, making the installation process simple and convenient, and effectively reducing the installation difficulty and cost. Moreover, the long arm of the shielding piece can guide the flue gas in advance to prevent the flue gas from flowing horizontally. When the flue gas reaches the connection between the long arm and the short arm, the guide portion guides the flue gas to flow along the shielding piece, reducing the direct impact of the particles in the flue gas on the expanded part of the plate.

[0019] Further, the side of the shielding piece that contacts the dust impact is coated with a wear-resistant coating.

[0020] With the foregoing technical solution, the wear-resistant coating itself has the characteristics of high hardness and high wear resistance, which can effectively resist the scratching and impact of dust particles, greatly reducing the wear of the shielding piece caused by long-term action of the flue gas, and further better maintaining the original shape and function of the guide portion, ensuring its accurate guiding effect on the direction of the flue gas flow.

[0021] Further, the shielding piece is clamped on the edge of the heat exchange plate by a screw.

[0022] With the foregoing technical scheme, when the shielding piece needs to be checked, repaired or replaced, the screw clamping structure makes the disassembly work easy and easy, and the clamping is carried out at the welding part, which reduces the influence on the heat exchange plate and also reduces the processing difficulty, improves the production efficiency.

[0023] Further, the shielding piece is fixed on the edge of the heat exchange plate by welding.

[0024] With the foregoing technical scheme, welding as a reliable connection method can form a stable and durable connection between the mounting part and the edge of the heat exchange plate, and the clamping is carried out at the welding part, which reduces the influence on the heat exchange plate and also reduces the processing difficulty, improves the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0025] The present application will be further described below in conjunction with the drawings:

[0026] Figure 1 It is a schematic diagram of a plate heat exchanger according to the present application;

[0027] Figure 2 It is a schematic diagram of a shielding piece in embodiment 2;

[0028] Figure 3 It is a schematic diagram of a shielding piece in embodiment 3;

[0029] Figure 4 It is a schematic diagram of a heat exchange plate with a guide part in embodiment 1.

[0030] BRIEF DESCRIPTION OF DRAWINGS: 1, heat exchange plate; 11, welding part; 12, gas flow cavity; 13, thin plate; 14, first end; 2, shielding piece; 22, guide part; 23, clamping groove; 3, wear-resistant coating; 4, short arm; 5, long arm. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments.

[0032] The terms "first", "second", etc. (if any) in the description and claims of the present application are used to distinguish similar objects, and are not used to describe a particular order or sequence, even if "second" is used before a certain technical feature to distinguish it. It should be understood that in the present application, "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. It should be understood that in the present application, "multiple" means two or more. "And / or" is only a description of the relationship between the associated objects, which means that there can be three relationships, for example, X and / or Y can represent three cases: X alone, X and Y together, and Y alone. The character " / " generally represents an "or" relationship between the associated objects. "Including X, Y and Z", "including X, Y, Z" means that X, Y and Z are all included, "including X, Y or Z" means that one of X, Y and Z is included, and "including X, Y and / or Z" means that any one or any two or all of X, Y and Z is included.

[0033] The technical solutions of the present application will be described in detail below with specific examples. The following specific examples can be combined or replaced according to actual conditions, and the same or similar concepts or processes may not be described in some examples.

[0034] Example 1:

[0035] As shown in Figure 1 The present application provides a plate heat exchanger, which comprises a heat exchange plate 1, the heat exchange plate 1 is fixed by welding a plurality of welding parts 11 between two thin plates 13, the non-welding parts of the thin plates 13 are away from each other to form a gas flow cavity 12, the edges of the two thin plates 13 of the heat exchange plate 1 close to the flue gas inflow side are first ends 14, the first ends 14 are fixed by welding parts 11, and the first ends 14 are provided with shielding pieces for shielding the welding parts on the first ends.

[0036] The application has the following advantages: in the complex working condition of dust-containing flue gas, the flue gas entering the heat exchanger is prone to vortex and turbulence, and the shielding piece 2 can partially shield the flue gas entering the heat exchanger, thereby avoiding the direct impact of dust particles in the flue gas on the parts of the plate sheet that are prone to damage, thereby significantly reducing the wear of the heat exchange plate 1, so that the service life of the plate heat exchanger in the dust-containing flue gas can be prolonged without increasing the thickness of the plate sheet, and when the heat exchanger is used for a long time, the shielding piece 2 is the first to be damaged, at which time the shielding piece 2 only needs to be removed and replaced with a new shielding piece 2 or repaired by welding, and then the heat exchange plate 1 can be reassembled, thereby reducing the use cost of the heat exchange plate 1, and since the shielding piece 2 is installed at the edge of the two thin plates 13, the edge welding part 11 can be protected from being impacted by the dust-containing flue gas, thereby preventing the welding part 11 from cracking, and the service life of the heat exchange plate 1 can be prolonged without affecting the heat dissipation efficiency of the heat exchange plate 1.

[0037] Specifically, the inlet of the flue gas is above the heat exchange plate 1, and the outlet of the flue gas is below the heat exchange plate 1, so the shielding piece 2 is installed on the upper welding part 11, and the gas flow cavity 12 of the heat exchange plate 1 is in an elliptical or circular shape, and the most vulnerable part of the heat exchange plate 1 is the expansion starting point of the gas flow cavity 12, that is, the intersection between the top of the elliptical or circular shape and the welding part 11, which has the largest wind area and the nearly vertical wind angle, so the thin plate at this position needs to be protected from the impact of dust particles.

[0038] Further, the shielding piece 2 wraps the welding part 11 on the first end 14 to shield the welding part 11 of the first end 14 close to the gas flow cavity 12.

[0039] According to the foregoing technical solution, since the first end 14 close to the gas flow cavity 12 is deformed by the thin plate 13, the windward curvature of the intersection between the welding part 11 of the first end 14 close to the gas flow cavity 12 and the gas flow cavity 12 is also the largest, so the damage caused by the impact of dust particles is the largest, and therefore the welding part 11 of the first end 14 is shielded by the shielding piece 2 to prevent direct impact of dust particles and prolong the service life of the welding part 11.

[0040] Further, the maximum thickness of the shielding piece 2 is greater than or equal to the maximum thickness of the heat exchange plate 1.

[0041] According to the foregoing technical solution, the wide enough shielding piece 2 can better regulate the flow path of the flue gas, and since the width covers a wide range, it can reduce the change in the flow cross section of the flue gas entering the heat exchanger, thereby ensuring the uniformity of the flue gas flow and reducing the wear of the heat exchange plate 1 caused by the dust-containing flue gas.

[0042] Further, the shielding piece 2 is provided with a clamping groove 23 matching the thickness of the first end 14.

[0043] By using the clamping groove 23 matching the thickness of the edge of the heat exchange plate 1 as the mounting part, the installation of the shielding piece 2 on the heat exchange plate 1 is more convenient. At the same time, the clamping groove 23 closely fits the edge of the heat exchange plate 1, which can provide stable and reliable connection, effectively prevent the shielding piece 2 from displacement or falling off due to vibration or flue gas impact during operation, and ensure that it is always in the correct working position, continuously playing a guiding role for flue gas and a protective role for the plate.

[0044] Further, the cross-sectional shape of the shielding piece 2 is inverted U-shaped, so that the opening of the clamping groove 23 is downwardly open, and the arc-shaped section of the shielding piece 2 faces the flue gas inflow direction.

[0045] By using the above technical solution, the cross-sectional shape of the shielding piece 2 is inverted U-shaped, so that it can wrap the key parts of the edge of the heat exchange plate 1 from multiple directions. And the opening of the inverted U-shaped is the clamping groove 23 of the shielding piece 2, which has simple structure and is easy to operate, and can be easily clamped on the edge of the heat exchange plate 1, realizing quick and convenient installation. When the flue gas enters the heat exchanger, it can be gradually guided by the arc-shaped section, reducing the turbulence and vortex caused by sharp turning, so that the flue gas is uniformly dispersed and flows over the heat exchange plate 1 at a more reasonable speed. This not only helps to reduce the direct impact of dust particles on the plate, but also improves the heat exchange efficiency, making the heat transfer between cold and hot fluids more sufficient and uniform.

[0046] Further, as shown in Figure 4 The shielding piece 2 is provided with a guide part 22, which is inclined to the flue gas flow direction, so that the flue gas is guided by the guide part 22 to be away from the heat exchange plate 1.

[0047] By using the above technical solution, the design of the guide part 22 inclined to the flue gas flow direction can change the flow path of the flue gas, actively guiding the flue gas to the direction away from the heat exchange plate 1, thereby more effectively avoiding the direct contact of dust particles with the heat exchange plate 1, especially its fragile parts, reducing the risk of wear and damage.

[0048] Further, the side of the shielding piece 2 contacting the dust impact is coated with a wear-resistant coating 3.

[0049] By using the above technical solution, the wear-resistant coating 3 itself has the characteristics of high hardness and high wear resistance, which can effectively resist the scratching and impact of dust particles, greatly reducing the wear of the shielding piece 2 due to long-term action of flue gas, and further better maintaining the original shape and function of the guide part 22, ensuring its accurate guiding effect on the flue gas flow direction.

[0050] Furthermore, the shielding member 2 is fixed to the edge of the heat exchange plate 1 by welding.

[0051] By adopting the above-mentioned technical solution, welding is used as a reliable connection method to form a stable and lasting connection between the mounting portion and the edge of the heat exchange plate 1, and the connection is performed at the welding portion 11, which reduces the impact on the heat exchange plate 1, reduces the processing difficulty, and improves production efficiency.

[0052] It can be understood that in another embodiment, the shielding member 2 is clamped to the edge of the heat exchange plate 1 by screws.

[0053] By adopting the above-mentioned technical solution, when the shielding member 2 needs to be inspected, repaired or replaced, the screw-clamping structure makes the disassembly work easy and convenient, and the clamping is performed at the welding portion 11, which reduces the impact on the heat exchange plate 1, reduces the processing difficulty, and improves production efficiency.

[0054] Example 2:

[0055] like Figure 2 As shown, the difference from Example 1 is that the cross-sectional shape of the shielding member 2 is an H-shape consisting of a short arm 4 and a long arm 5, the opening of the shielding member is open downward, the opening of the shielding member is adapted to the thickness of the welding portion on the first end, and the connection between the short arm 4 and the long arm 5 of the shielding member 2 is a guide portion 22.

[0056] The aforementioned technical solution uses the H-shaped opening as the mounting portion, allowing it to clip onto the edge of the heat exchange plate 1 like a clip. This makes installation simple and convenient, effectively reducing installation difficulty and cost. The long arm 5 of the shield 2 can pre-direct the flue gas to prevent lateral flow. When the flue gas reaches the junction of the long arm 5 and the short arm 4, the guide portion 22 guides the flue gas along the shield 2, reducing the direct impact of particles in the flue gas on the expanded portion of the plate.

[0057] Example 3: Figure 3 As shown, the difference from Example 1 is that the mounting portion does not use a slot to attach to the heat exchange plate, but is instead welded directly to the welded portion on the edge of the heat exchange plate. The entire shielding member 2 is constructed by welding two steel pipes and two steel plates together, forming a layout with two steel pipes and two steel plates positioned opposite each other. The steel pipes are then welded to the welded portion on the edge of the heat exchange plate at an angle, with the steel plates oriented in the direction of the flue gas flow and the steel pipes oriented in the direction of the flue gas flow.

[0058] In the above three embodiments, Figure 1 In the embodiment, the thickness of the shielding member is H2, the thickness of the welding portion on the first end is H1, and the thickness of the widest part of the heat exchange plate is H3, and their relationship is H3>H2>H1, or H2>H3>H1.

[0059] In addition to the preferred embodiments described above, other embodiments of the application will become apparent to those skilled in the art from the following detailed description, which shows and describes the preferred embodiments. It is to be understood that the foregoing detailed description and specific examples are presented as examples of the application and are not intended to be limiting.

Claims

1. A plate heat exchanger comprising heat exchange plates, which are fixed by welding of two thin plates through a number of welds, the non-welded parts of the thin plates being distanced from each other to form gas flow cavities, the two thin plates of the heat exchange plate having a first end near the edge of the flow-in side of the flue gas, the first end being fixed by a weld, characterized in that The first end is provided with a shielding piece for shielding the welding part on the first end.

2. A plate heat exchanger according to claim 1, characterised in that The shielding piece wraps the welding part on the first end so that the welding part near the first end of the gas flow cavity is shielded by the shielding piece.

3. A plate heat exchanger according to claim 1, characterised in that The maximum thickness of the shielding piece is greater than or equal to the maximum thickness of the heat exchange plate.

4. A plate heat exchanger according to claim 1, characterised in that The shielding piece is provided with a clamping groove matching the thickness of the welding part on the first end.

5. A plate heat exchanger according to claim 4, characterised in that The cross-sectional shape of the shielding piece is inverted U-shaped, so that the opening of the clamping groove is open downward, and the arc-shaped section of the shielding piece faces the direction of the flue gas inflow.

6. A plate heat exchanger according to claim 1, characterised in that The shielding piece is provided with a guide part which is inclined to the direction of the flue gas flow so that the flue gas is guided by the guide part to be away from the heat exchange plate.

7. A plate heat exchanger according to claim 6, characterised in that The cross-sectional shape of the shielding piece is h-shaped which is composed of a short arm and a long arm, the opening of the shielding piece is open downward, the opening of the shielding piece matches the thickness of the welding part on the first end, and the connection between the short arm and the long arm of the shielding piece is the guide part.

8. A plate heat exchanger according to claim 1, characterised in that The side of the shielding piece which contacts the impact of the soot is coated with a wear-resistant coating.

9. A plate heat exchanger according to claim 1, characterised in that The shielding piece is clamped on the edge of the heat exchange plate by screws.

10. A plate heat exchanger according to claim 1, characterised in that The shielding piece is fixed on the edge of the heat exchange plate by welding.

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