JP4531477B2 - Apparatus for brazing composition to flat tube and method thereof - Google Patents

Description

  The present invention relates to a brazing composition coating apparatus and a coating method for a flat tube used as a refrigerant circulation multi-hole tube tube in a heat exchanger or the like.

Conventionally, heat exchangers are manufactured by brazing fins to a multi-hole flat tube made of aluminum alloy.
In this case, a method is adopted in which an aluminum brazing sheet clad with brazing material on both sides is employed as the fin, and a non-corrosive flux for brazing is applied to the flat tube side (Japanese Patent Laid-Open No. 11-77292).
Until now, a method of spraying zinc as a pseudo-anode has been sometimes employed for the purpose of ensuring the corrosion resistance of a multi-hole flat tube made of an aluminum alloy.
Examples of methods for applying the brazing flux to the flat tube side include spraying, dipping, and shower spraying, but examples of adopting the roll transfer coating method to reduce manufacturing costs and reduce environmental impact (Japanese Patent Laid-Open Nos. 10-193094 and 2002-243378).

An aluminum alloy multi-hole flat tube made of extruded material has a plurality of holes through which a coolant flows, has a flat part for brazing fins at the top and bottom, and both sides of the flat part have side surfaces connecting the top and bottom flat parts. Exists.
The flux for brazing the fins was sufficient if it was applied to the upper and lower flat parts of the flat tube, but this time the zinc spraying process was abolished due to the demand for further cost reduction of the heat exchanger, and the zinc powder in the flux It was considered to disperse and apply.
If the zinc spraying process is abolished, corrosion resistance cannot be ensured unless a flux in which zinc powder is dispersed is also applied to the side surface of the flat tube.
However, the conventional roll transfer coating method can surely apply to the flat portion of the flat tube, but cannot apply to the side portion.
Therefore, as shown in FIG. 8, a method of applying the side surface portion 111 of the flat tube 110 by the spray coating method 81 and applying the flat surface portion 112 of the flat tube 110 by the roll transfer coating method 82 using the coating roll 145 was examined. However, it has been difficult to reduce the cost by the spray coating method.

Next, as shown in FIG. 9, first, a flat tube having a side part connecting the flat part on both sides is formed with an upper slope part and a lower slope part, and the rubber hardness of the application roll 145 is lowered to apply the flat part. The method of softening the roll 145 and applying the application roll 145 against the flat tube 110 was studied.
FIG. 10 shows the result of the application test by that method, and the upper slope portion 111 of the flat tube 110 is observed by 50 times magnification with an optical microscope.
As shown by 70, the range of the portion that can be applied on the coating roll side, and as shown by 71 for the uncoated portion, this method can only apply about half of the upper slope portion, and furthermore, the wear of the coating roll is large and the coating is applied. It was also assumed that the roll life would be reduced.
Therefore, further, as shown in FIG. 11, a method of coating with a coating roll 245 in which a groove 80 having the same shape as the upper inclined surface portion 111 of the flat tube 110 was examined.
Although the application area ratio to the upper slope portion of the flat tube could be improved by this method, there was a difference in the coating amount between the slope portion and the flat portion of the flat tube, and stable coating was difficult.
In addition, at the time of high-speed application with a higher flat tube feed rate, the flat tube was removed from the groove of the application roll, and a portion that was not applied at all occurred.
The difference in the coating amount has an effect on the corrosion resistance and brazing properties of the flat tube.If the coating amount is small, the corrosion resistance of the flat tube is reduced. The risk of refrigerant leakage increases. In addition, brazing between the flat tubes and the fins of the heat exchanger is not reliably performed, and the performance of the heat exchanger is deteriorated.
When the coating amount is large, the flux is eluted during brazing of the heat exchanger, and there is a possibility that a defect may occur in brazing between the flat tube and the fin of the heat exchanger.
From the above viewpoint, a more uniform high-speed coating apparatus and coating method were required.

Japanese Patent Laid-Open No. 10-193094 Japanese Patent Laid-Open No. 11-77292 JP 2002-243378 A

  In view of the above technical problem, the present invention provides a brazing composition coating apparatus and coating method that can be uniformly and rapidly applied to a flat tube used as a refrigerant circulation multi-hole tube in a heat exchanger or the like. For the purpose of provision.

Brazing composition to flat tube coating method in the present invention in cross section, flat portion 12a vertically, 12b and, on both sides of the upper slope portion 11a of the flat portion of the upper and lower, 11c and the lower inclined surface 11b , 11d for a flat tube having a shape connected to
A first side roll coater to be applied to the upper side slope part 11a and the lower side slope part 11d opposite to the first side roll coater to be applied to the upper side slope part 11c and the lower slope part 11b; The first and second side roll coaters each have a coating roll 45 and a squeezing roll 48 that are in direct contact with each other in an oblique direction, and the coating roll 45 is provided on the flat tube side, and the coating roll 45 and the squeezing roll 48 are provided. Are applied to the upper and lower slope portions, and are applied to the upper and lower plane portions 12a and 12b, respectively, by roll coaters 50a and 50b. The roll coaters 50a and 50b have application supply rolls 51a and 51b and transfer application rolls 52a and 52b,
The composition for filtration supplied to the applied product supply rolls 51a and 51b is applied to the upper and lower flat portions by the transfer application rolls 52a and 52b, and applied to the flat tube at a speed of 100 m / min or more. To do .

Here, since the slope portions on both sides of the flat tube are respectively composed of an upper slope portion and a lower slope portion, a pair of side roll transfer coating applied to a pair of opposed upper slope portions and lower slope portions. When two pairs of means are provided symmetrically, it can be applied continuously.
Further, from the viewpoint of stable supply of the coated material and uniform transferability, the side roll transfer coating means is composed of a squeeze roll for supplying the brazing composition and a coating roll for coating on the inclined portion of the flat tube. It is preferable that

As such a method for applying a brazing composition for a flat tube, a flat tube wound in a coil shape on a reel is stretched between a rewinding reel and a take-up reel, and the stretched flat tube is claimed. A brazing composition is applied using the flat tube brazing composition coating apparatus according to any one of 1 to 3, and is continuously dried and wound.
The brazing composition of the present invention is effective in the case of containing a brazing flux and zinc powder.

In the present invention, a flat tube having a flat portion on the upper and lower sides and a slope portion connecting the upper and lower flat portions on both sides is adopted, in addition to the roll transfer coating means for applying to the flat portion of the flat tube, By providing side roll transfer application means to apply to the slope part, there is little difference in the amount of application between the slope part and the flat part, no coating omission, stable application quality can be secured, and the corrosion resistance of the flat tube is improved. Further, it is possible to reduce the cost of manufacturing the flat tube.
In addition, it is not necessary to provide a groove on the coating roll, and the coated material can be stably supplied between the coating roll and the squeezing roll, and a flat tube wound in a coil shape around the reel is stretched between the rewinding reel and the take-up reel. It is possible to apply the brazing composition, continuously dry it and wind it up, enabling high-speed application and high productivity.

FIG. 1 shows a cross-sectional view of the flat tube 10 as an example.
The cross-section of the flat tube 10 is formed by upper and lower flat surface portions 12a and 12b, upper inclined surface portions 11a and 11c connecting the upper and lower flat surface portions 11a and 11b, and lower inclined surface portions 11b and 11d, and holes 13a, 13b, 13b,. It is a multi-hole tube tube having a plurality of.
Here, the upper slope portion 11a and the lower slope portion 11d facing each other are substantially parallel.
Similarly, the lower slope portion 11b and the upper slope portion 11c facing each other are substantially parallel.
In addition, the slope angle of the slope part is adopted according to the product and is not particularly limited. The joint part between the flat part and the slope part, and the joint part between the upper slope part and the lower slope part have a gentle round shape. It may be.
The flat tube 10 is made of an extruded material using an aluminum alloy or the like.
The upper and lower flat portions are brazed with an aluminum brazing sheet, but from the viewpoint of ensuring corrosion resistance, it is required to apply a flux in which zinc is dispersed all around the flat tube.

FIG. 2 shows 20 production lines of brazing composition-coated flat tubes.
The flat tube 10 wound in a coil shape is supplied from the rewind reel 21, and the flat tube 10 is wound on the take-up reel 25 side.
The flat tube that has been rewound is first subjected to plane adjustment by the rolling leveler 22.
Next, the constant speed feeding device 23 feeds at a high speed in consideration of the tension with the take-up reel side. Next, a pair of upper and lower side roll coaters 40a and 40b, which are side roll transfer means for applying the inclined portion of the flat tube, are provided in two rows, and a pair of upper and lower sides which are roll transfer means for applying the upper and lower flat portions of the flat tube 10. The brazing composition is continuously applied to the flat tube 10 with the roll coaters 50a and 50b.
Next, the brazing composition applied to the flat tube is dried in the drying furnace 24.
The brazing composition used here is preferably a mixed coating solution in which a brazing flux and a mixed powder of zinc (Zn) are stirred with a binder and a solvent.
The drying furnace 24 mentioned here is preferably provided with a far infrared device and a hot air device.
The atmosphere temperature in the drying furnace is preferably 200 ° C. to 400 ° C., in which case the drying time is about 6 seconds to 10 seconds.
Even when the coating line speed was 100 m / min or more, uniform coating was possible.

FIG. 3 schematically shows the flow of a brazing composition application process to a flat tube, and FIG. 4 shows a pair of upper and lower side roll coaters 40a and 40b.
Here, the side roll coater will be described with reference to FIG. 3. A pair of side roll coaters (40a, 40b) for simultaneously transferring and applying the lower slope portion 11b and the upper slope portion 11c, the upper slope portion 11a, and the lower slope portion 11d. Two sets of side roll coaters (40a, 40b) that simultaneously roll transfer coat are arranged symmetrically.
Since the top and bottom arrangements of the two (two pairs) rolls are only symmetrical, the same reference numerals are used for convenience.
In FIG. 3, for easy understanding, the coated material is expressed by reference numeral 31 larger (thicker) than actual.
In the example shown in FIG. 3, the lower slope portion 11b and the upper slope portion surface 11c are applied by the first side roll coater.
Next, the upper slope portion 11a and the lower slope portion 11d are applied by a second side roll coater.
Finally, the upper flat surface portion 12a and the lower flat surface portion 12b of the flat tube flat surface portion are applied by the roll coaters 50a and 50b.

As shown in FIG. 4, the side roll coater includes an upper side roll coater 40a, a lower side roll coater 40b, and a brazing composition collection tray 40c installed on a side roll coater base 40d.
The upper side roll coater 40a is retractable by a unit 41a provided on the side roll coater base 40d, and does not apply the pushing portion of the flat tube 10.
The upper side roll coater 40a rotates the upper application roll 45a connected to the upper application roll shaft 44a via the upper application roll gear 43a by using the motor 42a with a speed reducer as a drive source.
Then, the upper squeeze roll 48a connected to the upper squeeze roll shaft 47a via the upper squeeze roll gear 46a is also rotated.
The upper application roll 45a and the upper squeeze roll 48a are in direct contact with each other obliquely, and the upper application roll 45a is provided on the flat tube side.
The brazing composition is uniformly distributed and supplied to the upper coating roll 45a by pushing the coating material supplied between the upper coating roll 45a and the upper drawing roll 48a.
Since the lower side roll coater 40b is only arranged symmetrically with the upper side roll coater 40a, the description is omitted by substituting the subscript symbol a for b.
Hereinafter, the upper and lower application rolls are denoted by reference numeral 45, the upper and lower drawing rolls are denoted by reference numeral 48, and the like, and the suffixes a and b are omitted.
The brazing composition is supplied from a brazing composition tank 61 by a diaphragm pump 62.
The supplied brazing composition is uniformly distributed and supplied to the application roll 45 by the pressing of the application roll 45 and the squeeze roll 48 and reliably applied to the flat tube. The brazing composition squeezed during distribution supply is collected in the brazing composition collection tray 40 c and returned to the brazing composition tank 61 via the collection pump 63.
The material of the application roll 45 is preferably EP rubber, and the rubber hardness is preferably 40 to 80 degrees. This is because if the coating roll 45 is too soft, the wear resistance decreases and the life of the coating roll 45 decreases.
From such a viewpoint, butyl rubber and urethane may be used.
Even if the rotation speed of the coating roll 45 was 100 m / min or more and 150 m / min, uniform application to the inclined surface of the flat tube was possible.
The material of the squeeze roll 48 is preferably a steel roll subjected to chrome plating.
The rotation speed of the squeeze roll 48 is preferably 1/5 to 1/10 of the rotation speed of the coating roll 45. This is because at this speed, the brazing composition can be uniformly distributed and supplied, and coating unevenness can be reduced.
The pushing amount of the application roll 45 and the squeeze roll 48 is preferably 0 mm to 1 mm. This is because with this indentation amount, the brazing composition can be uniformly distributed and supplied, and the application amount can be reduced while reducing application unevenness.

Rotating the coating roll 45 in the same direction as the travel direction of the flat tube 10 is referred to as forward rotation coating. Contrary to this, applying in the reverse direction with respect to the traveling direction of the flat tube is called reverse rotation application.
Generally, when it is desired to increase the coating amount or to reduce the unevenness in the appearance, the reverse rotation coating is performed. However, in the reverse rotation coating, the coating roll 45 is more worn compared to the forward rotation coating.
In the present invention, the application range of the slope portion is narrow, and there is little coating unevenness in appearance even in forward rotation application.
The roll coaters 50a and 50b for applying the flat surface portion 12a and the flat surface portion 12b supply the application liquid with the applied material supply rolls 51a and 51b, and apply them to the flat tube from both the upper and lower surfaces with the transfer application rolls 52a and 52b.

FIG. 5 shows the evaluation results of the sloped part coating amount of the flat tube, the sloped part coating area ratio, and the sloped part appearance coating unevenness by changing the coating roll pressing amount at a predetermined line speed.
FIG. 6 shows the results of coating evaluation in which the pushing amount of the coating roll 45 and the squeezing roll 48 is changed at a line speed of 100 m / min.
In FIG. 7, the example of a coating evaluation result with a coating area ratio of 98% enlarged 50 times with an optical microscope is shown.
As can be seen from these results, there is no coating omission in the appearance at each coating speed, and a slope area application area ratio of 95% or more can be secured.
Then, the variation of the slope portion coating amount could be suppressed within ± 2g / m ^2.

An example of a cross section of a flat tube is shown. A brazing composition-coated flat tube production line 20 is shown. The coating process schematic diagram to the flat tube 10 is shown. The schematic diagram of a side roll coater is shown. The application test result of a flat tube is shown. The test results of the roll push-in amount and the coating amount (attachment amount) are shown. The example of an application surface observation result expanded 50 times with the optical microscope is shown. An example of a method in which the inclined portion of the flat tube 110 is applied by a spray coating method and the flat portion of the flat tube is applied by a roll transfer coating method will be described. An example of a method in which the rubber hardness of the coating roll 145 is lowered and pressed is shown. The coating result obtained by magnifying and observing the surface of the coating roll 145 with the rubber hardness reduced 50 times with an optical microscope is shown. An example of an application roll 245 in which a groove having the same shape as the inclined surface portion 111 of the flat tube 110 is formed is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Flat tube 11a, 11c Upper slope part 11b, 11d Lower slope part 12a Upper plane part 12b Lower plane part 20 Brazing composition application | coating flat pipe production line 21 Rewinding reel 22 Rolling leveler 23 Constant speed feeding apparatus 24 Drying Furnace 25 Take-up reel 31 Coating surface 40a Upper side roll coater 40b Lower side roll coater 40c Brazing composition recovery tray 40d Side roll coater base 41a Upper unit 41b Lower unit 42a Upper motor with reduction gear 42b Lower reduction motor with motor 43a Upper coating roll gear 43b Lower coating roll gear 44a Upper coating roll shaft 44b Lower coating roll shaft 45a Upper coating roll 45b Lower coating roll 46a Upper squeezing roll gear 46b Lower squeezing roll gear 47a Upper squeezing roll shaft 47b Bottom aperture Shaft 48a Upper squeeze roll 48b Lower squeeze roll 50a Upper roll coater 50b Lower roll coater 61 Brazing composition tank 62 Diaphragm pump 63 Recovery pump 70 Application part 71 Unapplication part 80 Roll groove 81 Spray application method 82 Roll transfer application Law

Claims (1)

Cross section, flat section in the vertical (12a, 12b) and the upper inclined surface portions on both sides of the flat portion of the upper and lower (11a, 11c) and the lower inclined surface (11b, 11d) in flattened pipe having the connected shape and for,
The second machine to be applied to the upper slope part (11a) and the lower slope part (11d) facing the first side roll coater to be applied to the upper slope part (11c) and the lower slope part (11b) facing each other. Side roll coater
The first and second side roll coaters each have an application roll (45) and a squeeze roll (48) that are in direct contact with each other in an oblique direction, and the application roll (45) is provided on the flat tube side. The brazing composition supplied between the roll (45) and the squeeze roll (48) is distributed and supplied to the coating roll (45), and is applied to the upper slope and the lower slope.
Roll coaters (50a, 50b) to be applied to the upper and lower plane portions (12a, 12b), respectively;
The roll coater (50a, 50b) has a coated product supply roll (51a, 51b) and a transfer coating roll (52a, 52b),
The composition for filtering supplied to the applied product supply rolls (51a, 51b) is applied to the upper and lower flat portions by the transfer application rolls (52a, 52b), and applied to the flat tube at a speed of 100 m / min or more. A method for applying a composition for brazing a flat tube .