JP2670512B2 - Heat transfer element plate stack - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a laminate formed by laminating a plurality of heat transfer element plates having an enlarged heat transfer surface of a regenerative heat exchanger.

[Prior Art] Various types in which a heat transfer coefficient per unit volume of a laminated body of heat transfer element plates constituting a fluid passage is made as high as possible and a pressure loss of a fluid passing through a unit volume passage is made as low as possible. Have been proposed.

As a general tendency seen in these proposals, the larger the heat transfer coefficient, the denser the heat transfer element plate in the unit volume and the pressure loss increases. The likelihood of clogging of the dust contained in the dust increases.

Among such technical trends, a typical one having various performances such as heat transfer coefficient, pressure loss, uniform distribution of fluid flow, blocking resistance of flow passage, and ease of manufacturing in a most balanced manner. As the laminated body of the heat transfer element plates, CU type and DU type laminated bodies already exist, and the structure, function, etc. thereof will be described below.

2 (a) is a cross-sectional view of a pair of laminated bodies of CU type heat transfer element plates, and FIG. 2 (b) is a top view thereof.

This laminated body comprises a heat transfer element plate 2 having an enlarged heat transfer surface having waves having a pitch P _{1 which} is not more than twice the height H ₁ of a large wave type 1 (Corrugated groove type), and a small wave type 3 ( Undulated gr
the heat transfer element plates 4 having an expanded heat transfer surface having a wave having a pitch P _{2 which} is not more than 6 times the height H ₂ of the A laminated body (referred to as a CU type) of heat transfer element plates in which a hydraulic diameter of a fluid passage cross-section 16 constituted between 4 is 7 mm or less.

The fluid flow path is configured by stacking a plurality of pairs of stacked bodies.

The direction of the peaks 5 of the large wave type 1 of the heat transfer element plate 2 is the same as the inflow direction 6 of the fluid flowing into the laminated body, and the direction of the peaks 5 of the small wave type 3 of the heat transfer element plate 4 is the inflow direction. 6 and angle A
It runs through a slope (35 ° or less).

The heat transfer mechanism of the CU type laminate is one of the CU type heat transfer element plates.
The following description can be made with reference to FIG. 3, which shows a cross-sectional view of a wave of one pitch of a pair of laminated bodies.

The thin layer fluid 7 that flows in contact with the heat transfer surface of the large wave type 1 is
Heat is efficiently exchanged by heat transfer with the surface. The fluid 8 flowing in contact with the fluid 7 mixes with the fluid 7 to efficiently increase its own heat transfer coefficient that it originally had. The thin-layer fluid 9 flowing in contact with the heat transfer surface of the small wave type 3 efficiently exchanges heat with the surface, and at the same time, the peaks 5 of the small wave type 3 oblique to the flow of the fluid cause the fluid 9 to change to the fluid 9. The fluid 10 is vigorously mixed with the fluid 10 that is in contact with the fluid 10 to form a turbulent flow, and the heat transfer coefficient of the fluid 10 is efficiently increased. Fluid 7, 8, 9 and fluid 10
Mixes with the fluid 11 flowing without contacting the fluid 7 and the fluid 9 to make the fluid 11 a turbulent flow and improve the heat transfer coefficient of the fluid 11.

Comprehensively considering the heat transfer mechanism of each of the aforementioned partial fluids in the flow path cross section formed between the heat transfer element plates 2 and 4, the fluid flowing in the flow path cross section becomes a violent turbulent flow as a whole. And has a high heat transfer coefficient.

However, due to the violent turbulent flow, it is unavoidable to cause a considerable pressure loss.

Furthermore, since the hydraulic diameter of the cross section of the flow channel is 7 mm or less and the cross section of the flow channel is narrow and overflows, the flow channel is easily blocked by the dust contained in the fluid.

FIG. 4 (a) is a sectional view of a pair of laminated bodies of DU type heat transfer element plates, and FIG. 4 (b) is a top view thereof.

This laminate has a height of large wave type 1 (Notched groove type).
Have 5 times or less of the wave pitch P ₁ of the H _1, further pitch P ₁ of the wave
In the middle part of the wavelet 12 (Undulated groove type), a heat transfer element plate 13 having an expanded heat transfer surface having a wave having a pitch P _{3 which} is 6 times or less of the height H ₃ of the wavelet 3 and the wavelet 3 (Undulated groove type)
The is formed an enlarged heat transfer surface having a height 6 times or less of the wave pitch P ₂ of the H ₂ and the heat transfer element plates 14 are alternately stacked, between the stacked heat transfer element plates 13 and 14 Cross-section of the fluid flow path 16
Of heat transfer element plates with a hydraulic diameter of 8.5 mm or more (DU
Type).

The fluid flow path is configured by stacking a plurality of pairs of stacked bodies.

The peaks 5 of the large wave type 1 of the heat transfer element plate 13 pass in the same direction as the inflow direction 6 of the fluid flowing into the laminated body.
The ridges 5 of 12 pass through the inflow direction 6 at an angle B (35 ° or less), and the ridges 5 of the wave-shaped 3 of the heat transfer element plate 14
The heat transfer mechanism of the DU type laminated body, which also passes through the inclination of the angle A (35 ° or less), is the same as that of the DU type heat transfer element plate.
The following description can be made with reference to FIG. 5, which shows a cross-sectional view of a wave of one pitch of a pair of laminated bodies.

The thin layer fluid 7 that flows in contact with the heat transfer surface of the large wave type 1 is
Heat is efficiently exchanged by heat transfer with the surface. The fluid 8 flowing in contact with the fluid 7 mixes with the fluid 7 to efficiently increase its own heat transfer coefficient that it originally had. The thin-layer fluid 7'flowing in contact with the heat transfer surface of the wavelet 12 efficiently exchanges heat with the surface, and at the same time, the valley 15 of the wavelet 12 obliquely intersects with the flow of the fluid. 'And violently mix with the fluid 8 flowing in contact with the
Efficiently increase the heat transfer coefficient of self that it had at the beginning of.
Further, the fluids 7, 7'and the fluid 8 are the fluids 7, 7'and the fluid 9
The fluid 11 is mixed with the fluid 11 flowing without contacting the to make the fluid 11 a turbulent flow, and the heat transfer coefficient of the fluid 11 is also improved. The fluid 9 in a thin layer flowing in contact with the heat transfer surface of the wavelet 3 efficiently exchanges heat with the surface, and is converted into the fluid 9 by the peaks 5 of the wavelet 3 oblique to the flow of the fluid. Fluid flowing in contact
Vigorous mixing with the fluid 10 makes the fluid 10 a turbulent flow, increasing the heat transfer coefficient of the fluid 10 that it originally had. Further, the fluid 9 and the fluid 10 are the same as the fluid 7, 7 ′ and the fluid 8,
The fluid 11 is mixed with the fluid 11 which does not come into contact with 7'and the fluid 9 to make the fluid 11 a turbulent flow and also improve the heat transfer coefficient of the fluid 11. However, the heat transfer coefficient of the fluid 11 is larger than that of the CU type in which the hydraulic diameter of the flow passage cross section of this laminated body is larger, so that the fluid 11 in FIG. 3 is vigorously mixed to improve the heat transfer coefficient. Is not improved.

Considering the heat transfer mechanisms of the respective partial fluids in the cross section of the flow path formed between the heat transfer element plates 13 and 14 in total, the fluid flowing in the cross section of the flow path is
It has a lower heat transfer coefficient than the CU type and, as a whole, a lower pressure drop than the CU type, as it is not as turbulently turbulent as in the CU type.

Furthermore, the hydraulic diameter of the channel cross section is 8.5 mm or more, and the cross section of the channel has a cross section wider than the CU type,
The flow path is unlikely to be blocked by the dust contained in the fluid.

In the CU type laminated body of FIG. 2 (a), the heat transfer element plate 2,
Most of the flux flowing through the flow path cross section 16 formed between 4 is
In the large wave type 1 passing through the same direction as the inflow direction 6 of the fluid shown in FIG. 2B, a small portion of the flux passes through the inflow direction 6 of the fluid and forms an angle A. Since it is guided by the mountain 5 of the small wave type 3 and is deflected to the left from the straight direction,
Flux flowing through flow channel cross section 16 and flow channel cross section 1 on both sides of it
The flux flowing through 6 ', 16 "is something which mixes to a certain extent, but the mixing is insufficient.

In the DU type laminate shown in FIG. 4 (a), the heat transfer element plate 1
Most of the flux flowing in the flow path cross section 16 formed between 3 and 14 is guided by the large wave type 1 passing in the same direction as the inflow direction 6 of the fluid shown in FIG. 4 (b). The valley 15 of the small wave type 12 and the peak 5 of the small wave type 3 in which the small part of the flux passes straight at an angle B with the inflow direction 6 of the fluid.
Is deflected to the left from the direction of straight travel, so that the flux flowing in the channel cross section 16 and the channel cross sections 16 ′, 16 ″ on both sides thereof
The flux that flows through is something that mixes to some extent; the mixing is inadequate.

[Problems to be Solved by the Invention] In a laminate of heat transfer element plates employed in a regenerative heat exchanger, a heat transfer coefficient and a pressure loss per unit volume,
The demands for uniform distribution of fluid flow, blockage resistance of stacks, manufacturability, etc. are becoming more and more stringent year by year, and they are satisfied with the performance of stacks of conventional heat transfer element plates. I can't let it happen.

Increasing the heat transfer coefficient of the laminate generally complicates the shape of the expanded heat transfer surface and increases the pressure loss, and also increases the blockage of the flow path due to dust in the fluid. This results in reduced manufacturability.

Further, the uneven flow due to the uneven flow of the fluid flowing through the flow path of the laminated body causes a local low temperature portion in the laminated body to cause acid condensation due to the acid dew point, thereby generating dust and acid contained in the exhaust gas. It is not possible to sufficiently mix with the base SOx to reduce the floating SOx due to the adsorption of SOx by dust, resulting in corrosion of the heat transfer element plate.

The object of the present invention is to have a higher heat transfer coefficient and a uniform distribution of fluid flow than the conventional stack of heat transfer element plates, but the pressure loss is relatively low, and further the expansion is achieved. It is an object of the present invention to provide a laminate of heat transfer element plates with improved productivity due to the simplification of the structure of the heat transfer surface.

[Means and Actions for Solving the Problems] The laminated body of the heat transfer element plates is a wave having a pitch of 7.5 times or less the height of the corrugation, and is located substantially at the center of the height of the corrugation. And an expanded heat transfer surface that is a wave that has a flat plate portion that is located in the middle of the wave pitch and is substantially parallel to the line that connects the wave-shaped peaks and has a width wider than the width of the wave shape. A flow path cross section of a fluid, which is configured by alternately stacking heat element plates and another heat transfer element plate having a mirror-symmetrical shape with the heat transfer element plates, and is formed between the heat transfer element plates after being stacked. Is a laminated body of heat transfer element plates having a hydraulic diameter of 7.5 mm or more.

In order to promote uniform mixing of the fluid flowing in the flow path between the heat transfer element plates, the direction of the wave-shaped peaks of the transfer element plates forms an inclination of 15 ° to 35 ° with the direction of the fluid flowing into the stack. I am passing through.

Since the corrugated web imparts sufficient rigidity to the heat transfer element plates against the pressing force applied during the production and stacking of the heat transfer element plates, the corrugated web is perpendicular to the flat plate portion located in the middle of the wave pitch. It is inclined at an angle C (35 ° or less) with respect to the plane.

Example An example of the present invention will be described below with reference to the drawings.

FIG. 1 (a) is a cross-sectional view of a pair of laminates of FNC type heat transfer element plates, and FIG. 1 (b) is a top view thereof.

The height of this laminated body is large wave type 1 (Notched groove type)
A cross-section having a wave pitch P ₁ of 7.5 times or less H _1,
Furthermore, the upper surface of the flat plate part 17 (flat plate) and the crests of the large wave type 1 5,5
, The lower surface of the flat plate portion 17 and the valley of the large wave type 1
By making the distance from the line connecting 15 and 15 equal, the area of the flow passage cross section 16 formed between the heat transfer element plates 18 and 19 is defined by the line connecting the valleys 15 and 15 of the large wave type 1. In order to divide it into two equal parts, they are arranged parallel to the line connecting the valleys 15 and 15 in the center of the height H ₁ of the large wave type 1 and in the middle of the wave pitch P ₁ , and the flow path cross section 16 In order to hold down the hydraulic diameter of the small wave to a small value, the cross section has a flat plate portion 17 having a width F wider than the width W of the large wave 1 (the width is narrower than W in the figure). The heat transfer element plates 18 forming the heat transfer surface and the heat transfer element plates 19 having a mirror-symmetrical shape formed by reversing the heat transfer element plates 18 are alternately stacked, and the stacked heat transfer elements are stacked. The hydraulic diameter of the cross section 16 of the flow path of the fluid formed between the thermal element plates 18 and 19 is
A stack of heat transfer element plates with a size of 7.5 mm or more (referred to as FNC type)
It is. The fluid flow path is configured by stacking a plurality of pairs of stacked bodies.

The direction of the peaks 5 of the large wave type 1 of the heat transfer element plates 18 or 19 is such that the flow path cross section 1 of the fluid formed between the stacked heat transfer element plates 18 and 19 is
In order to promote uniform mixing of the respective fluids flowing through 6 and the flow passage cross sections 16 ', 16 "adjacent to the cross section 16 with each other, the inflow direction 6 of the fluid flowing into the stack and the angle D ( 15
゜ ~ 35 ゜) with a slope.

The web 20 of the large wave type 1 has a vertical surface 21 with respect to the flat plate portion 17 in order to impart strong rigidity to the heat transfer element plate 18 or 19 against a pressing force applied during manufacturing and stacking of the heat transfer element plate 18 or 19. It has an inclination of an angle C (35 ° or less).

The heat transfer mechanism of the FNC type laminated body can be explained as follows using FIG. 6 which shows a sectional view of a wave of one pitch of a pair of laminated bodies of the FNC type heat transfer element plates. it can.

The thin fluid 7 flowing in contact with the heat transfer surfaces of the heat transfer element plates 18 and 19 efficiently exchanges heat with the surfaces by heat transfer. The fluid 8 flowing in contact with the fluid 7 mixes with the fluid 7 to efficiently improve its own heat transfer coefficient that it originally had.

The fluid 11 flowing without contacting the fluid 7 mixes with the fluid 7 and the fluid 8 to form a turbulent flow. The heat transfer coefficient of the fluid 11 is
Since the hydraulic diameter of the flow passage cross section of this laminated body is larger than that of the CU type, the fluid 11 in FIG. 3 is vigorously mixed and its heat transfer coefficient is not improved to the extent that it is improved. Although the hydraulic diameter of the cross section of the flow path is smaller than that of the DU type, the fluid 11 in FIG. 5 is mixed to the same extent as or slightly less than that of the fluid 11, that is, using FIG. The fluid 11 in FIG. 5 is mixed by the factors of the heat transfer mechanism described in FIG.

FIG. 7 shows a perspective view of a pair of laminates of FNC type heat transfer element plates.

Among the fluids that flow in the inflow direction 6 with respect to the stack, most of the fluid that has passed through the upper half flow path 22 has an inclination of 15 ° to 35 ° with the inflow direction 6 of the fluid. The arrow is guided by the large wave type 1 of the upper heat transfer element plate 23 obliquely crossing to the right.
24, while most of the fluid that has passed through the lower half flow path 25 intersects the inflow direction 6 of the fluid to the left with an inclination of 15 ° to 35 °. Large wave type 1 of heat element plate 26
It is guided by and flows in the direction of arrow 27.

The cross-sectional areas of the flow path 22 and the flow path 25 are equal, and both flat plate portions 17, 17 are parallel to each other, and the corresponding portions are equidistant from the dotted line 28 indicating the center of the cross section. twenty four
It can be considered that the flow rate and the flow velocity of the fluid flowing as described above and the fluid flowing as indicated by the arrow 27 are substantially equal over the entire cross section of the flow path.

The fluid indicated by the arrow 24, which is a branch of the fluid in the inflow direction 6, and the fluid indicated by the arrow 27 ″, which is a branch of the fluid in the inflow direction 6 ″, have a vertical positional relationship and intersect obliquely. Similarly, the fluid of the arrow 27 and the fluid of the arrow 24 ', which are shunts of the fluid in the inflow direction 6 and the fluid in the inflow direction 6', intersect in the same manner.

Therefore, the flow in the upper half of the flow path 22 and the flow in the lower half of the flow path 25 are always subjected to a shearing force at the contact surface between the two flows, and the two fluids are mixed with each other at the time of shearing to cause a turbulent flow. Flows.

The momentum of the fluid flowing on the upper side and the momentum of the fluid flowing on the lower side are equal because the flow rate and the flow velocity of the respective fluids are substantially equal. Therefore, when the mixed state of the two fluids is a necessary and sufficient mixed state without excess and deficiency, it is possible to cause a phenomenon that the heat transfer coefficient has a maximum value with respect to the generated pressure loss. What causes this necessary and sufficient mixed state is not only that the momentums of the upper and lower fluids are equal, but also that they are laminated adjacent to the conditions of the cross-sectional form of the heat transfer element plate laminate of the present invention. Needless to say, it is premised that the heat transfer element plate has an oblique angle range of 15 ° to 35 °.

Focusing on separating the fluid flowing through the flow passage 22 and the flow passage 25 into substantially equal parts is that when the respective momentums of the upper half fluid and the lower half fluid are unequal, the momentum The fluid on the side with less momentum becomes a turbulent flow with excessive vortex flow by the fluid on the side with high momentum, increasing the pressure loss more than the effect of improving the heat transfer coefficient, while the fluid on the side with high momentum has momentum The turbulent flow with insufficient vortex flow due to the fluid on the side of the lower side increases the pressure loss unnecessarily even though the heat transfer coefficient cannot be improved. This is to avoid the occurrence of the phenomenon that the heat transfer coefficient is not improved in spite of the increased pressure loss and the heat transfer coefficient cannot reach the maximum value.

The following is a comparison of the heat transfer characteristics per unit volume of each of the CU type, DU type and FNC type laminates having the same flow path length.

CU type DU type FNC type Heat transfer coefficient ratio 110 100 106 Pressure loss ratio 138 100 98 Weight ratio 132 100 105 FNC type has a high heat transfer rate for pressure loss,ゝ It indicates that it has a heavy weight.

The heat transfer mechanism of the conventional CU type and DU type laminates, and each of the aforementioned in the flow path cross section 16 configured between the heat transfer element plates 18 and 19 of the FNC type laminate of the embodiment of the present invention. Comparing the heat transfer mechanism of each partial fluid and considering comprehensively,
As a whole, the degree of fluid vortex in the FNC type is lower than that in the CU type, but it is the same as that in the DU type, but the flow is larger than that in the DU type. Since it is a vortex flow that is evenly distributed in the FNC type, the heat transfer coefficient of the FNC type shows an intermediate value between the CU type and the DU type, and the pressure loss is lower than the CU type and shows the same or lower value as the DU type. ing.

FIG. 8 shows that a basket 30 is filled with a laminated body 29 of heat transfer element plates, air is supplied to the flow path of the laminated body 29 in the direction of the inflow direction 6, and the air pressure is pitted at the outlet of the flow path. Tube 31 to arrow 32
An apparatus for measuring while moving in the direction of is shown.

The pressure distribution of air when the CU type is filled as shown in FIG. 9 is as shown in FIG. 9, when the DU type is filled, as shown in FIG. 10, and when the FNC type is filled, FIG. It is like.

For CU and DU type pressure distribution, basket 30
It is shown that the pressure decreases as it approaches the right end wall of the, and it shows that the mutual mixing of the fluid is not uniformly performed between the flow paths arranged in the left-right direction of the laminate 29. . On the other hand, in the pressure distribution of the FNC type, such a decrease in the pressure is not observed but is constant, which indicates that the fluids are evenly mixed with each other.

In FIG. 1 (a), FNC type heat transfer element plates 18 and 1
9 shows that the flat plate portion 17 existing in the middle portion of the wave pitch P ₁ does not have the small wave type 12 existing in the DU type heat transfer element plate 13 of FIG. Tend to be smaller. In order to improve this tendency, the rigidity is strengthened by setting the inclination within 35 ° or less from the vertical surface 21 of the flat plate portion 17 of the web 20 of the large corrugation 1 of the FNC type heat transfer element plates 18 and 19. I am measuring. By this strengthening means, the pressing force applied when the FNC type heat transfer element plates 18 and 19 are cut into a desired size by a cutting machine, and the heat transfer element plates 18 that act when the heat transfer element plates 18 and 19 are stacked. As described in detail above, the stack of FNC-type heat transfer element plates adopts the theory of contact heat transfer mechanism while transferring many shapes of heat transfer. The experiment was repeated on the laminated body of heat element plates, and the heat transfer coefficient was high despite the low pressure loss that could not be obtained by the conventional laminated body of heat transfer element plates, and the fluid mixability was good and the pressure was high. It was possible to find the best shape of the heat transfer element plate, which has a uniform distribution and a simple shape of the expanded heat transfer surface, but has high rigidity.

[Effect of the Invention] The laminate of the heat transfer element plates of the present invention has a pressure loss in the laminate of the heat transfer element plates of various shapes, provided that the flow length of the heat exchange fluid of the heat exchanger is constant. Shows the highest heat transfer coefficient, while the heat transfer stack has a constant heat transfer coefficient, the lowest pressure loss.

Since the fluidity of the laminate of the heat transfer element plates is even and the flow path of the heat exchanger does not flow unevenly, a local low temperature may be generated at the low temperature end of the laminate of the heat exchanger. No, it does not cause water corrosion and does not cause acid condensation even when exhaust gas containing SOx flows, and when the exhaust gas contains a large amount of dust in addition to SOx, SOx and dust Are evenly mixed to promote the adsorption of SOx on dust and suppress the generation of acid due to floating SOx. Therefore, it is possible to reduce the corrosion of the laminated body, and when NH ₃ is introduced into the exhaust gas denitration device, a trace amount of NH ₃ that leaks from the device into the exhaust gas downstream of the device and floats. Generation of acidic ammonium sulfate, which is deposited on the heat transfer surface by combination with SOx, can be suppressed, and blockage of the flow path of the laminate can be prevented.

Enlargement of heat transfer element plateSince the shape of the heat transfer surface is simplified, the workability of the heat transfer element plate is simplified, while the rigidity of the heat transfer element plate due to the simplified shape Can be prevented by specifying the inclination angle of the large wave type web, the manufacturing cost of the laminate of the heat transfer element plates can be reduced, and the weight of the heat exchanger can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view and a top view of the FNC type laminated body.
The figure is a cross-sectional view and top view of a CU type laminated body.
FIG. 4 is a sectional view of a 1-pitch laminated body, FIG. 4 is a sectional view and a top view of a DU-shaped laminated body, and FIG. 5 is a 1-pitch sectional view of a DU-shaped laminated body. FIG. 6 is a sectional view of the FNC type laminated body for one pitch, FIG. 7 is a perspective view of the FNC type laminated body, and FIG. 8 is a pressure distribution measuring device of the flow passage of the laminated body. Yes, FIG. 9 shows the pressure distribution of the CU type laminated body, FIG. 10 shows the pressure distribution of the DU type laminated body, and FIG. 11 shows
It is a pressure distribution of a FNC type laminated body. 1 ... Large wave type, 2 ... Heat transfer element plate, 3 ... Small wave type, 4 ...
... heat transfer element plate, 5 ... mountain, 6, 6'6 "... inflow direction, 7,
7 ′, 8,9,10,11 …… Fluid, 12 …… Small wave type, 13,14 …… Heat transfer element plate, 15 …… Valley, 16,16 ′, 16 ″ …… Flow section, 17… …
Flat plate part, 18, 19 ... Heat transfer element plate, 20 ... Web, 21 ...
Vertical surface, 22 ... Channel, 23 ... Heat transfer element plate, 24, 24 ', 24 "
...... Arrows, 25 ...... Flow paths, 26 ...... Heat transfer element plates, 27,27'2
7 ″ …… Arrow, 28 …… Dotted line, 29 …… Stack, 30 …… Basket, 31 …… Pitot tube, 32 …… Arrow.

Claims (1)

(57) [Claims] 1. A line having a wave with a pitch not more than 7.5 times the height of the corrugation, located at the center of the height of the corrugation, and in the middle of the pitch of the corrugation, connecting the peaks of the corrugations. Has a flat plate portion that is parallel to and is wider than the width of the corrugation, and has a corrugated peak in a direction that makes an inclination of 15 ° to 35 ° with the direction of the fluid flowing into the laminated body, A heat transfer element plate having a wave-shaped web having a vertical surface with respect to the flat plate portion and an inclination of 35 ° or less, and a heat transfer element plate having a mirror-symmetrical shape with the heat transfer element plate are alternately laminated and laminated. A laminate of heat transfer element plates, characterized in that the hydraulic diameter of the flow path cross section formed between the heat transfer element plates is 7.5 mm or more.