How to check the quality of a heat exchanger

Abstract

To provide a method for conforming quality of a heat exchanger that does not require the use of a large amount of hot air.SOLUTION: A method for confirming quality of a heat exchanger comprises: a step ST11 of performing a hydraulic pressure test in which liquid is sealed in a pressurized state into a first flow path and a second flow path of the heat exchanger having the first flow path and the second flow path adjacent to the first flow path; a step ST12 of discharging liquid from the first flow path and the second flow path; and a step ST13 of reducing pressure in the first flow path and the second flow path with a vacuum pump to promote evaporation of the liquid remaining in the first flow path and the second flow path. In the step ST13 of promoting the evaporation of the liquid, heated gas is fed into the first flow path and the second flow path.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for verifying the quality of a heat exchanger. [Background technology]

[0002] It has been known to perform a pressure test on a heat exchanger after it has been assembled, as disclosed in the following Patent Document 1. In Patent Document 1, a pressure test is performed after the assembly of the heat exchanger is completed by applying a pressure of, for example, 45 kg / cm 2 The heat exchanger is pressurized by sealing in an aqueous solution (aqueous solution of ammonium carbonate and ammonium bicarbonate) at a pressure of 1000 kJ / s. The quality of the heat exchanger can be confirmed by conducting a pressure test. After the pressure test, hot air at 230°C is blown in at a flow rate of 14 m / s. 3 Air is also blown into the heat exchanger at a volume of 1 / min to dry the inside of the heat exchanger. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 118643 / 1983 Summary of the Invention [Problem to be solved by the invention]

[0004] In the method disclosed in Patent Document 1, hot air at 230°C is used for hot air drying, and it takes 4 to 5 hours to complete the drying. Therefore, a large amount of hot air is required to complete the quality check, which increases the cost of performing the quality check.

[0005] Therefore, the present invention has been made in consideration of the above-mentioned conventional technology, and its object is to provide a method for checking the quality of a heat exchanger that does not require the use of a large amount of hot air. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the quality confirmation method for a heat exchanger of the present invention is a quality confirmation method for a heat exchanger, which includes the steps of: performing a hydraulic test in which a liquid is sealed under pressure in a first flow path and a second flow path adjacent to the first flow path of a heat exchanger; discharging the liquid from the first flow path and the second flow path; and heating the first flow path and the second flow path and reducing the pressure in the first flow path and the second flow path using a vacuum pump to promote evaporation of the liquid remaining in the first flow path and the second flow path. The process of promoting evaporation of the liquid includes a first process of reducing the pressure in the first flow path and a second process of reducing the pressure in the second flow path before or after the first process is performed, wherein in the first process, heated gas is sent to the second flow path, and in the second process, heated gas is sent to the first flow path.

[0007] In the quality confirmation method of the present invention, a hydraulic test is performed in which a liquid is sealed in a pressurized state in the first and second flow paths. This allows the integrity of the heat exchanger to be confirmed by checking for deformation or damage to the heat exchanger and for the occurrence of liquid leakage. Furthermore, after the liquid used in the hydraulic test is discharged from the heat exchanger, the pressure in the first and second flow paths is reduced to promote evaporation of the liquid remaining in the flow paths. This prevents adverse effects caused by the liquid remaining in the heat exchanger. Furthermore, because the evaporation of the remaining liquid is promoted by reducing the pressure in the flow paths, the energy required to dry the inside of the heat exchanger can be reduced compared to drying the inside of the heat exchanger by blowing hot air into the heat exchanger at atmospheric pressure. This prevents the cost of quality confirmation of heat exchangers from increasing.

[0009] AlsoIn this method, the pressure in the first flow path and the pressure in the second flow path are reduced separately. In the first step, in which the pressure in the first flow path is reduced, the second flow path is heated, and the temperature in the first flow path also increases as the second flow path is heated. In other words, when the second flow path is heated, the heat in the second flow path is transferred to the first flow path, so the pressure in the first flow path is not only reduced but also increased. Therefore, evaporation of the remaining liquid can be promoted while suppressing the degree of pressure reduction in the first flow path. In other words, the liquid in the first flow path can be evaporated without a very high degree of vacuum in the first flow path (i.e., without a very low pressure). Therefore, the pump power required for the evaporation promotion step can be reduced. Similarly, in the second step, evaporation of the liquid remaining in the second flow path can be promoted. In other words, since the liquid is evaporated by heating while reducing the pressure in the first and second flow paths, the temperature of the gas sent into the flow path can be kept low compared to a method in which the liquid is evaporated by heating without reducing the pressure in the flow paths.

[0010] The first step may be terminated on the condition that it is confirmed that the pressure in the first flow path has been reduced to a predetermined pressure or less, and the second step may be terminated on the condition that it is confirmed that the pressure in the second flow path has been reduced to a predetermined pressure or less.

[0011] In this embodiment, the predetermined pressure is set to, for example, a pressure at which the flow paths reach a state where almost no liquid remains. When the pressure in the first flow path and the pressure in the second flow path reach this set pressure, the first step and the second step are completed, and a state where almost no liquid remains in the flow paths of the heat exchanger can be achieved.

[0014] The quality confirmation method may further include a step of confirming that the liquid does not remain in the first flow path and the second flow path. In this aspect, it is possible to assure a user of the heat exchanger that no liquid remains in the first flow path and the second flow path.

[0015] The heat exchanger may be a stacked heat exchanger. 。 [Effects of the Invention]

[0016] As described above, according to the present invention, the quality of a heat exchanger can be checked without using a large amount of hot air. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view of a stacked heat exchanger that is the subject of a quality confirmation method. [Figure 2] 3A and 3B are diagrams illustrating a flow path structure of the heat exchanger. [Figure 3] 3A to 3C are diagrams for explaining each step of the quality confirmation method. [Figure 4] FIG. 3 is a diagram showing a heat exchanger when a first step in the quality confirmation method is performed. [Figure 5] FIG. 4 is a view showing a heat exchanger when a second step in the quality confirmation method is performed. [Figure 6] FIG. 10 is a diagram showing a heat exchanger when a first step is performed in a quality confirmation method according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0019] The quality confirmation method according to this embodiment is a quality confirmation method for a heat exchanger 10, which is a stacked heat exchanger as shown in FIGS. 1 and 2. This method is performed after the heat exchanger 10 is manufactured and before the heat exchanger 10 is shipped to a customer. Before specifically describing this method, the configuration of the heat exchanger 10 will be described. Note that the heat exchanger 10 to be quality confirmed is not limited to the heat exchanger 10 shown in FIGS. 1 and 2 as long as it is a stacked heat exchanger. For example, it may be a plate heat exchanger having multiple stacked plates, with the gaps between the plates configured as flow channels. Furthermore, the heat exchanger 10 may be a microchannel heat exchanger configured by stacking multiple plates with multiple grooves formed on their surfaces and bonding the plates together to form flow channels between adjacent plates. The heat exchanger 10 may be made of aluminum, stainless steel, titanium, or the like.

[0020] 1 and 2 is a plate-fin heat exchanger configured to exchange heat between a first fluid and a second fluid. The heat exchanger 10 is equipped with headers 11 and 12 for the first fluid and headers 13 and 14 for the second fluid. The headers 11 and 12 for the first fluid include a first distribution header 11 through which the first fluid passes before flowing into the heat exchanger 10 and a first collection header 12 through which the first fluid passes after flowing out of the heat exchanger 10. The headers 13 and 14 for the second fluid include a second distribution header 13 through which the second fluid passes before flowing into the heat exchanger 10 and a second collection header 14 through which the second fluid passes after flowing out of the heat exchanger 10.

[0021] The heat exchanger 10 includes a large number of partition plates 21, each made of a flat plate, and corrugated fin plates 22 arranged between adjacent partition plates 21. The large number of partition plates 21 are arranged at intervals in one direction (the thickness direction of the partition plates 21; hereinafter, also referred to as the stacking direction), and the fin plates 22 are arranged between each partition plate 21.

[0022] Each fin plate 22 is joined to a pair of partition plates 21 located on both sides thereof. This forms a large number of flow paths 23 between the partition plates 21. Another fin plate 22 is connected to the opposite side of the partition plate 21, so that a large number of flow paths 23 are formed on each side of the partition plate 21. The flow paths 23 located on one side of the partition plate 21 function as a large number of first flow paths 25 through which a first fluid flows, and the flow paths 23 located on the other side of the partition plate 21 function as a large number of second flow paths 26 through which a second fluid flows. In other words, the first flow paths 25 and the second flow paths 26 are adjacent to each other with the partition plate 21 sandwiched between them.

[0023] The multiple first flow paths 25 (first flow path groups) are arranged to line up in the width direction of the partition plate 21 (diagonal direction in FIG. 1 and left-right direction in FIG. 2), and each first flow path 25 extends in the longitudinal direction of the partition plate 21 (vertical direction in FIG. 1 and depth direction in FIG. 2). The multiple second flow paths 26 (second flow path groups) are also arranged to line up in the width direction of the partition plate 21 (diagonal direction in FIG. 1 and left-right direction in FIG. 2), and each second flow path 26 extends in the longitudinal direction of the partition plate 21 (vertical direction in FIG. 1 and depth direction in FIG. 2). The first layers 29 having the multiple first flow paths 25 (first flow path groups) and the second layers 30 having the multiple second flow paths 26 (second flow path groups) are alternately stacked in the stacking direction (diagonal direction in FIG. 1 and up-down direction in FIG. 2). Therefore, the multiple first flow paths 25 and second flow paths 26 are also lined up in the stacking direction.

[0024] The first flow paths 25 are each connected to the inner space of the first distribution header 11 and the inner space of the first collecting header 12. Therefore, the first fluid introduced into the first distribution header 11 flows into each first flow path 25, and the first fluid that has flowed through each first flow path 25 is merged into the first collecting header 12. In addition, the second flow paths 26 are each connected to the inner space of the second distribution header 13 and the inner space of the second collecting header 14. Therefore, the second fluid introduced into the second distribution header 13 flows into each second flow path 26, and the second fluid that has flowed through each second flow path 26 is merged into the second collecting header 14.

[0025] Each first layer 29 and each second layer 30 has side bars 33 on both widthwise sides of the partition plate 21. The side bars 33 close both widthwise ends of the fin plate 22 between a pair of partition plates 21. By providing the side bars 33, even when pressure in the first flow path 25 and the second flow path 26 acts on the fin plate 22, the fin plate 22 can withstand the pressure.

[0026] An outer plate 34 is provided at each end in the stacking direction of the heat exchanger 10. The outer plate 34 is made of a flat plate material that is thicker than the partition plate 21, and by providing the outer plate 34, even when the pressure in the first flow path 25 and the second flow path 26 acts on the partition plate 21, the partition plate 21 can withstand the pressure.

[0027] 1 is a heat exchanger 10 provided with only the first flow path 25 and the second flow path 26, but is not limited to this. For example, the heat exchanger 10 may be configured to be provided with a third flow path (not shown) in addition to the first flow path 25 and the second flow path 26, and to perform heat exchange among the first fluid, the second fluid, and the third fluid. In this case, for example, a configuration may be adopted in which a large number of second flow paths 26 for passing the second fluid are adjacent to a large number of first flow paths 25 for passing the first fluid, and a large number of third flow paths for passing the third fluid are adjacent to the large number of second flow paths 26.

[0028] Next, with reference to FIG. 3 , a quality confirmation method for the heat exchanger 10, which is performed after the heat exchanger 10 is assembled, will be described. In this quality confirmation method for the heat exchanger 10, a hydraulic pressure test is first performed (hydraulic pressure test step ST11). The hydraulic pressure test is a test in which the first flow path 25 and the second flow path 26 are filled with liquid and the insides of the flow paths 25, 26 are maintained in a pressurized state. To this end, one opening of the first distribution header 11 and the first collection header 12, which communicate with the first flow path 25, is closed with a plug member (not shown), and the other opening is connected to a pipe (not shown). A liquid (e.g., water) is introduced into the first flow path 25 through this pipe. At this time, the liquid is sealed in the first flow path 25 so that the first flow path 25 is filled with a pressure higher than the pressure determined by the required specifications of the heat exchanger 10. This pressure is at least higher than atmospheric pressure.

[0029] Then, the first flow path 25 is left in this state for a predetermined time. At this time, the second flow path 26 may be open to the atmosphere, or may be closed. After the predetermined time has elapsed, the plug member is removed and the liquid in the first flow path 25 is discharged (discharge step ST12).

[0030] Next, a hydraulic pressure test is performed on the second flow path 26 by filling it with liquid in the same manner as the hydraulic pressure test on the first flow path 25 (hydraulic pressure test step ST11). After a predetermined time has elapsed, the liquid in the second flow path 26 is drained (draining step ST12). Note that the hydraulic pressure test may be performed on either the first flow path 25 or the second flow path 26 first.

[0031] Next, an evaporation promotion step ST13 is performed to evaporate the liquid remaining in the first flow path 25 and the second flow path 26. The evaporation promotion step ST13 is a step of promoting evaporation of the liquid remaining in the flow paths 25, 26 by reducing the pressure in the flow paths 25, 26 and heating the flow paths 25, 26. The evaporation promotion step ST13 includes a first step ST13a in which the pressure in the first flow path 25 is reduced but the pressure in the second flow path 26 is not reduced, and a second step ST13b in which the pressure in the second flow path 26 is reduced but the pressure in the first flow path 25 is not reduced. Note that, although the second step ST13b is performed after the first step ST13a here, the second step ST13b may also be performed before the first step ST13a.

[0032] 4, in the first step ST13a, a suction pipe 40 equipped with a vacuum pump 37 and a vacuum gauge 38 is connected to one of the first distribution header 11 and the first collecting header 12, and a vacuum gauge 41 is connected to the other, so that the first flow path 25 can be depressurized. In addition, a heating pipe 43 for feeding heated gas (hot air) is connected to one of the second distribution header 13 and the second collecting header 14, and the other is left open.

[0033] Then, in the first step ST13a, the vacuum pump 37 is operated to reduce the pressure inside the first flow path 25, and heated gas is sent to the second flow path 26 through the heating pipe 43. In addition, in the first step ST13a, the heat exchanger 10 itself is also heated. That is, the heat exchanger 10 is covered with a cover 45 made of a heat insulating material, and heated gas (hot air) is sent into the inner space of this cover 45. The gas (hot air) sent may have a temperature of 100°C or higher, or may have a temperature of 100°C or lower.

[0034] In the first step ST13a, the degree of vacuum in the first flow path 25 is checked using the vacuum gauges 38 and 41, and the vacuum pump 37 is operated until the degree of vacuum reaches a predetermined value. That is, the first step ST13a is terminated on the condition that it is confirmed that the pressure in the first flow path 25 has been reduced to or below the predetermined pressure. As long as liquid remains in the first flow path 25 and this liquid continues to evaporate, the pressure in the first flow path 25 will not drop below the predetermined pressure. Therefore, by continuing to operate the vacuum pump 37 until the pressure in the first flow path 25 drops below the predetermined pressure, the state in which liquid remains in the first flow path 25 can be eliminated. At this time, the second flow path 26 is heated, and the heat exchanger 10 itself is also heated, so the temperature in the first flow path 25 also rises. Therefore, not only is the pressure in the first flow path 25 reduced, but the evaporation of the liquid in the first flow path 25 is promoted by heating the first flow path 25. Since the pressure inside first flow path 25 is reduced, the temperature of the gas flowing out from first flow path 25 may be equal to or lower than the boiling point of the liquid used under atmospheric pressure. For example, when the liquid is water, the temperature of the gas flowing out from first flow path 25 may be 100°C or lower.

[0035] 5, the suction pipe 40 is reconnected from one of the first distribution header 11 and the first collecting header 12 to one of the second distribution header 13 and the second collecting header 14, and the vacuum gauge 41 connected to the other of the first distribution header 11 and the first collecting header 12 is removed and attached to the other of the second distribution header 13 and the second collecting header 14. The heating pipe 43 attached to one of the second distribution header 13 and the second collecting header 14 is removed and connected to one of the first distribution header 11 and the first collecting header 12. The cover 45 is left covering the heat exchanger 10.

[0036] Then, in the second step ST13b, the vacuum pump 37 is operated to reduce the pressure inside the second flow path 26, and heated gas is sent to the first flow path 25 through the heating pipe 43. In addition, in the second step ST13b, the heat exchanger 10 itself is also heated. As a result, the pressure inside the second flow path 26 is not only reduced but also heated, which promotes evaporation of the liquid inside the second flow path 26.

[0037] Then, the degree of vacuum in the second flow path 26 is confirmed by the vacuum gauges 38 and 41, and the second step ST13b is terminated on the condition that it is confirmed that the pressure in the second flow path 26 has been reduced to a predetermined pressure or less.

[0038] Next, it is confirmed that no liquid remains in the first flow path 25 and the second flow path 26 (confirmation step ST14). Specifically, a gas with a known dew point that is lower than the required dew point is sealed into each of the first flow path 25 and the second flow path 26, and the gas is left in this state for a predetermined period of time. Examples of gases with known dew points include nitrogen gas, helium gas, argon gas, and dry air. Note that other gases may also be used, but in this case, the dew point should be measured using a dew point meter before sealing the gas in the heat exchanger 10.

[0039] After a predetermined time has elapsed, the sealed gas is discharged from the first flow path 25, and the dew point of the discharged gas is measured with a dew point meter. The dew point of the gas sealed in the second flow path 26 is also measured in the same manner.

[0040] If the dew point is equal to or lower than a predetermined value (required dew point), this means that no moisture remains in the first flow path 25 and the second flow path 26, and the quality check is terminated. However, if the dew point exceeds the predetermined value, the evaporation promotion step ST13 is performed again.

[0041] As described above, the quality confirmation method of this embodiment performs a hydraulic test in which a pressurized liquid is sealed in the first flow path 25 and the second flow path 26, making it possible to confirm whether or not the liquid is leaking from the heat exchanger 10. Furthermore, after the liquid used in the hydraulic test is discharged from the heat exchanger 10, the pressure in the flow paths 25 and 26 is reduced to promote evaporation of the liquid remaining in the flow paths 25 and 26. This prevents adverse effects caused by the liquid remaining in the heat exchanger 10. Furthermore, because the evaporation of the remaining liquid is promoted by reducing the pressure in the flow paths 25 and 26, the energy required to dry the interior of the heat exchanger 10 can be reduced compared to when hot air is blown into the heat exchanger 10 at atmospheric pressure to dry the interior of the heat exchanger 10. This prevents the cost of performing a quality confirmation of the heat exchanger 10 from increasing.

[0042] Furthermore, in the quality confirmation method, the pressure reduction of the first flow path 25 and the pressure reduction of the second flow path 26 are performed separately. In the first step ST13a in which the pressure reduction of the first flow path 25 is performed, the second flow path 26 is heated, and the temperature of the first flow path 25 also increases as the second flow path 26 is heated. In other words, when the second flow path 26 is heated, the heat of the second flow path 26 is transferred to the first flow path 25, so the pressure in the first flow path 25 is not only reduced but also increased. Therefore, evaporation of the remaining liquid can be promoted while suppressing the degree of pressure reduction in the first flow path 25. In other words, the liquid can be evaporated without a very high degree of vacuum in the first flow path 25 (i.e., without a very low pressure). Therefore, the pump power required for the evaporation promotion step ST13 can be reduced. In the second step ST13b, evaporation of the liquid remaining in the second flow path 26 can be promoted in a similar manner. That is, since the liquid is evaporated by heating while reducing the pressure inside the flow paths 25, 26, the temperature of the gas sent into the flow paths 25, 26 can be kept lower than in a method in which the liquid is evaporated by heating without reducing the pressure inside the flow paths 25, 26. Therefore, even if the heat exchanger 10 is made of, for example, aluminum, deterioration of the material can be prevented.

[0043] Moreover, the predetermined pressure set as a condition for ending the first step ST13a and the second step ST13b is set to, for example, a pressure at which a state in which almost no liquid remains in the flow paths 25, 26 is reached. When the pressure in the flow paths 25, 26 reaches this set pressure, the first step ST13a and the second step ST13b are ended, and therefore a state in which almost no liquid remains in the flow paths 25, 26 of the heat exchanger 10 can be achieved.

[0044] Furthermore, since the confirmation step ST14 is also performed, it is possible to assure the user of the heat exchanger 10 that no liquid remains in the first flow path 25 and the second flow path 26.

[0045] In this embodiment, in the evaporation promotion step ST13, hot air is sent into the first flow path 25 and the second flow path 26 to heat the flow paths 25, 26, but heating the first flow path 25 and the second flow path 26 may be omitted. In this case, the pressure in the first flow path 25 and the second flow path 26 may be reduced simultaneously without dividing the step into the first step ST13a and the second step ST13b.

[0046] Furthermore, in this embodiment, in the evaporation promotion step ST13, heated gas is sent into the first flow path 25 and the second flow path 26 and the heat exchanger 10 itself is heated, but it is also possible not to heat the heat exchanger 10 itself in the evaporation promotion step ST13.

[0047] It is also possible to omit the confirmation step ST14. In this case, in the first step ST13a and the second step ST13b, it may be confirmed that no liquid remains by checking that the degree of vacuum has dropped below a predetermined value.

[0048] Furthermore, instead of the confirmation step ST14, a step of continuously circulating gas having a dew point lower than the required dew point through the first flow path 25 and the second flow path 26 for a predetermined time or more may be performed. In other words, a state in which the dew point is sufficiently lowered may be ensured without actively measuring the dew point.

[0049] (Other embodiments) The disclosed embodiments are illustrative in all respects and should not be considered limiting. The present invention is not limited to the above-described embodiments, and various modifications and improvements are possible without departing from the spirit and scope of the present invention. For example, in the quality confirmation method of the above-described embodiment, the heat exchanger 10 itself is heated and heated gas is sent to the first flow path 25 and the second flow path 26 in the evaporation promotion step ST13. However, this is not limiting. That is, in the evaporation promotion step ST13, the heat exchanger 10 itself may be heated without sending heated gas to the first flow path 25 and the second flow path 26. For example, as shown in FIG. 6 , in the evaporation promotion step ST13, the heat exchanger 10 is covered with a cover 45, and heated gas (hot air) is sent into the inner space covered by this cover 45 to heat the heat exchanger 10. Furthermore, to depressurize the first flow path 25, a suction pipe 40 equipped with a vacuum pump 37 and a vacuum gauge 38 is connected to one of the first distribution header 11 and the first collection header 12, and a vacuum gauge 41 is connected to the other. Then, the vacuum pump 37 is operated to reduce the pressure inside the first flow path 25 (first step ST13a). In the first step ST13a, the degree of vacuum inside the first flow path 25 is checked using the vacuum gauges 38 and 41, and when the degree of vacuum reaches a predetermined value, the first step ST13a is completed.

[0050] Next, in order to reduce the pressure in the second flow path 26, a suction pipe 40 equipped with a vacuum pump 37 and a vacuum gauge 38 is connected to one of the second distribution header 13 and the second collection header 14, and a vacuum gauge 41 is connected to the other. Then, the vacuum pump 37 is operated to reduce the pressure in the second flow path 26 (second step ST13b). In the second step ST13b, the degree of vacuum in the first flow path 25 is confirmed using the vacuum gauges 38 and 41, and when the degree of vacuum reaches a predetermined value, the second step ST13b is completed.

[0051] In this method, the degree of pressure reduction when the first flow path 25 and the second flow path 26 are reduced by the vacuum pump 37 can be reduced. In other words, by heating the heat exchanger 10 itself, the liquid can be evaporated without a very high degree of vacuum in the first flow path 25 and the second flow path 26 (i.e., without a very low pressure). Therefore, the pump power required for the evaporation promotion step ST13 can be reduced. Although a heat source is required to heat the heat exchanger 10, this heat source is not used to directly heat and evaporate the liquid remaining in the flow paths 25 and 26, but rather to heat the depressurized flow paths 25 and 26. Therefore, compared to a method in which the liquid is directly heated and evaporated, the temperature of the heat exchanger 10 can be kept low, thereby preventing an increase in costs.

[0052] In the case of Figure 6, the suction pipe 40 may be connected not only to the first flow path 25 but also to the second flow path 26, and the first step ST13a of depressurizing the first flow path 25 and the second step ST13b of depressurizing the second flow path 26 may be performed simultaneously. [Explanation of symbols]

[0053] 10: Heat exchanger 23: Flow path 25: First flow path 26: Second flow path 37: Vacuum pump ST11: Hydraulic pressure test process ST12: Discharge process ST13: Evaporation promotion process ST13a: 1st process ST13b: 2nd process ST14: Confirmation process

Claims

1. A method for verifying the quality of a heat exchanger, comprising: a step of conducting a hydraulic test of a heat exchanger having a first flow path and a second flow path adjacent to the first flow path by sealing a liquid in a pressurized state in the first flow path and the second flow path; Discharging the liquid from the first flow path and the second flow path; and heating the first flow path and the second flow path and reducing the pressure in the first flow path and the second flow path by a vacuum pump to promote evaporation of the liquid remaining in the first flow path and the second flow path, the step of promoting evaporation of the liquid includes a first step of reducing the pressure in the first flow path and a second step of reducing the pressure in the second flow path before or after the first step is performed, In the first step, a heated gas is sent to the second flow path; The quality check method for a heat exchanger, wherein in the second step, heated gas is sent to the first flow path.

2. the first step is terminated on the condition that it is confirmed that the pressure in the first flow path has been reduced to a predetermined pressure or less; 2. The method for checking the quality of a heat exchanger according to claim 1, wherein the second step is terminated on the condition that it is confirmed that the pressure in the second flow path has been reduced to a predetermined pressure or less.

3. The method for checking the quality of a heat exchanger according to claim 1 or 2, further comprising the step of confirming that no liquid remains in the first flow path and the second flow path.

4. 3. The method for checking the quality of a heat exchanger according to claim 1, wherein the heat exchanger is a laminated heat exchanger.

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