JPH064228Y2 - Plate heat exchanger - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention relates to a plate heat exchanger used as an economizer for oil-fired boilers, a heater for cogeneration oil-fired engine exhaust gas heat recovery, and the like. .

(Conventional example) Conventionally, a plate formed by arranging a plurality of heat exchanger plate cores each having a flow passage formed therein at predetermined intervals, and installing these in a flow passage through which a heat medium such as exhaust gas flows. In the heat exchanger of the type, a horizontally projecting supply / discharge pipe is connected to the upper and lower end portions of the side edges of each plate core by welding, and each of the supply / discharge pipes forms the heat medium flow path. It is attached to the frame and penetrates through the machine frame to be piped to the outside. Therefore, each plate core is integrally attached to the machine frame through the supply / discharge pipes at the upper and lower ends thereof.

(Problems to be solved by the invention) When the plate cores are firmly attached to the flow passages for circulating the high heat medium by the machine frame as described above, the plate cores through which the heat exchange fluid flows and the high heat medium are directly connected to each other. This will cause a phenomenon in which the amount of thermal expansion and contraction differs between the machine frame and the machine frame.

Then, the stress due to the difference in the amount of thermal expansion and contraction is applied to the supply / discharge pipe, particularly the connecting portion between the supply / discharge pipe and the plate core, which causes a crack in the connecting portion to cause water leakage. .

Furthermore, when connecting the supply and discharge pipes to each plate core, the outer diameter of the supply and discharge pipe is larger than the thickness of each plate core,
When the plate cores are arranged side by side, the supply and discharge pipes adjacent to each other protrude from the plate cores, and therefore the gap between the adjacent plate cores cannot be reduced, which increases the flow velocity of the heat medium between the plate cores. I couldn't.

In view of the above conventional problems, the present invention reduces the stress applied to the connection between the plate core and the supply / discharge pipe as much as possible, and the protrusion amount of the supply / discharge pipe connected to each plate core is greater than that of the plate core. It is an object of the present invention to provide a plate heat exchanger capable of reducing the gap between the plate cores without being hindered by this, even if it is large.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention is a plate in which a plurality of heat exchange plate cores 3 in which a flow path 8 is formed are arranged in parallel at predetermined intervals. In the heat exchanger 2
The elbow-shaped supply / discharge pipes 4, 5 communicating with the inlet and outlet of the flow path 8 are connected to the upper and lower edges of the plate cores 3, respectively, and the elbow-shaped supply / discharge pipes 4, 5 on the upper and lower edges are mutually connected. A configuration is adopted in which the radii of curvature are different and the connection positions thereof are displaced from each other in the horizontal direction.

(Embodiment) An embodiment of the present invention will be described below with reference to the attached exemplary drawings.

In FIG. 1 and FIG. 2, 1 is a vertical exhaust gas flow path that flows downward in the exhaust gas, and 2 is a heat exchanger of the present invention installed in the exhaust gas flow path 1. The heat exchanger 2
Is a plurality of heat exchange plate cores 3 arranged side by side at predetermined intervals in the lateral direction, and an elbow-shaped supply / discharge pipe such as an L-shape or a four-half arc shape connected to the upper and lower edges of the plate core 3. 4, 5 and a panel plate 6 which is a machine frame to which the plate cores 3 are integrally attached via the supply / discharge pipes 4, 5.

As shown in FIGS. 3 and 4, each of the heat exchange plate cores 3 has two rectangular plates 3a and 3b which are stacked on each other.
In between, a flow path 8 having a flat shape along both surfaces of the plate and having a cross-sectional shape in which both end shoulders 7 are gently inclined is provided between both plates 3
A and 3b are divided into seam welds 9 that are welded to each other in a continuous line to form a zigzag shape, and both side plates 3a and 3b of the flow path 8 are provided at positions at appropriate intervals in the length direction of the flow path 8. Are indented inward in a circular shape, and both plates 3a, 3b are connected to each other by spot welding 11 at the bottom of the recessed portions 10a, 10b. Further, the upper and lower edges of the plate core 3 are connected to the inlet and outlet of the flow path 8. The communicating arc-shaped connecting portions 12 and 13 are formed, and one end of each of the supply and discharge pipes 4 and 5 is fitted into each of the connecting portions 12 and 13 and is fixed by welding 21.

Further, as shown in FIG. 1, the above-mentioned vertically facing connecting portions 12 and 13 have their mounting positions horizontally different from each other, and one of their upper and lower edges is away from the side edge of the plate core 3. While the other side is attached near the side edge of the plate core, the other connecting portion 12 away from the side edge of the plate core 3 has a large radius of curvature R. 4 is connected to the other connecting portion 13, and a supply / discharge pipe 5 having a small radius of curvature r is connected to the other connecting portion 13.

As shown in FIGS. 1 and 2, the panel plate 6
On the outside of the, the communication chamber 15 that encloses the open ends of the fluid supply / discharge pipes 4 and 5 that are arranged in a staggered pattern in the lateral direction on the upper end side, and the fluid supply / discharge devices that are arranged in a staggered pattern in the lateral direction on the lower end side A communication chamber 16 including the open ends of the pipes 4 and 5 is provided, and connection pipes 17 and 18 are provided in the communication chambers 15 and 16, respectively. Reference numerals 17a and 18a are openings provided in the inner ends of the connecting pipes 17 and 18 in a lateral direction.

In the heat exchanger 2 configured as described above, each plate core 3 is fitted into the exhaust gas flow passage 1 through the opening 19 provided in one side wall of the exhaust gas flow passage 1 so as to be parallel to the exhaust gas flow direction. The opening 19 is closed by the panel plate 6. Reference numeral 20 is a support member projecting from the other side wall of the exhaust gas passage 1 to support the free end of each plate core 3.

In the above heat exchanger 2, the communication chamber below the connecting pipe 18
When water is supplied to 16, the water flows into the zigzag-shaped flow path 8 from the fluid supply / discharge pipes 4 and 5 of the plate cores 3 opening in the communication chamber 16, and the water flows upward in the zigzag-shaped flow path 8. After flowing, it flows out from the upper fluid supply / discharge pipes 4 and 5 into the communication chamber 15 and is discharged via the connection pipe 17,
In this process, while the high-temperature exhaust gas flowing in the exhaust gas passage 1 from top to bottom flows through the gap α between the plate cores 3, the water in the passage 8 passes through the plates 3a and 3b. Heat exchange is performed with the exhaust gas in the gap α, and the water in the flow path 8 is heated and discharged.

Here, the high temperature exhaust gas comes into contact with the panel plate 6 that integrates the plate cores 3 to reach a high temperature, whereas the plate cores 3 do not reach such a high temperature because water flows in the flow path 8. Therefore, the amount of heat expansion and contraction of both differs due to the difference in the amount of heat received by both, the material, the thickness, etc. For this reason, the supply and discharge pipes attached between the two, especially the connection part (welded part) with the plate core 3
There is a risk that stress will concentrate on 21 and cracks will occur,
In this respect, in the present invention, the supply / discharge pipes 4, 5 are L-shaped or 4
Since it is formed in an elbow shape such as a semi-circular shape, even if the panel plate 6 has a larger thermal expansion amount than the panel core 3 as shown by the chain double-dashed line, as shown in FIG. Following this, the supply / discharge pipes 4 and 5 are elastically deformed as shown by the chain double-dashed line, and the local load on the connecting portion 21 is reduced, and the occurrence of cracks can be prevented as much as possible.

Furthermore, the elbow-shaped supply / discharge pipes 4 and 5 attached to the upper and lower edges of the plate core 3 are formed to have different radii of curvature, and the attachment positions thereof are provided so as to be displaced from each other in the horizontal direction. Plate core 3,3
2 and 3 are arranged side by side, the plate cores 3 are alternately inverted and arranged so that the supply and discharge pipes 4 and 5 having different mounting positions are adjacent to each other as shown in FIGS. 2 and 3. The supply and discharge pipes 4 and 5 are positioned so as not to collide with each other but to be in conflict with each other, thereby making the gap α between the plate cores 3 and 3 as small as possible.
It is possible to improve the heat exchange efficiency by increasing the flow velocity of the heat medium such as exhaust gas flowing through the pipe, and to manufacture only one type of plate core 3 with the same supply / discharge pipe 4 and 5 mounting positions for mass production. It is advantageous.

(Effect of the Invention) According to the present invention, even if a high heat medium is circulated between the plate cores, the concentrated stress due to the thermal expansion to the connection part between each plate core and the supply / discharge pipe is reduced, and the cracks at the connection part are reduced. It can be used stably for a long period of time by preventing the occurrence of.

Moreover, according to the present invention, even if the outer diameter of the supply / discharge pipe connected to each plate core is larger than the thickness of each plate core, the heat medium distribution gap between each plate core is made as small as possible. The flow velocity of the heat medium can be increased and the heat exchange efficiency can be increased.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a heat exchanger of the present invention in use, FIG. 2 is a front view of a cutaway portion of the same portion, and FIG.
II is a view, FIG. 4 is a view of IV-IV of FIG. 1, and FIG. 5 is an explanatory view showing the principle of thermal stress absorption. 1 ... Exhaust gas flow path, 2 ... Heat exchanger, 3 ... Plate core,
4, 5 ... Supply and discharge pipes, 8 ... Flow paths.

Claims (1)

[Scope of utility model registration request] 1. A plate heat exchanger comprising a plurality of heat exchanging plate cores in which flow passages are formed side by side at predetermined intervals, wherein the flow passages are provided at upper and lower edges of each plate core. An elbow-shaped supply / discharge pipe communicating with the inlet / outlet of the elbow is connected, and the elbow-shaped supply / discharge pipes at the upper and lower edges are formed to have different radii of curvature, and the connecting positions are displaced from each other in the horizontal direction. Plate type heat exchanger provided.