KR100514696B1 - treatment heat exchanger of brazing - Google Patents

Abstract

The present invention adopts nickel plating type or paste coating type of work without using expensive filler metal, which is an expensive solvent in brazing operation of the conventional plate heat exchanger. I would like to suggest a way to braze.

Description

A brazing method of a heat exchanger and a heat exchanger brazed by the method. {Treatment heat exchanger of brazing}

The present invention relates to a brazing method of a heat exchanger, and more particularly, to a method of brazing a plate-type heat exchanger by a nickel plating method and a paste coating method and a heat exchanger brazed by the above method.

Typically, the heat exchanger has a structure in which a plurality of plates, in particular, a plurality of cooling plates and separation plates are brazed to each other to form a flow path through which a refrigerant flows therebetween. The separating plate is formed in a flat plate shape, and the cooling fins are formed in a wave shape to form a flow path of the refrigerant between the separating plate and to increase heat exchange efficiency.

Meanwhile, the brazing method of the heat exchanger configured as described above is as follows.

First of all, in the configuration of the heat exchanger, the cooling fins and the separating plate are processed by sequentially processing the shaling, notching, drawing, tropping, piercing, and washing, and then the filler metal to bond the cooling fins and the separating plate to each other ( After the filler metal), the filler metal is formed on the upper and lower surfaces of the separator.

That is, after casting the alloying element to melt the ingot (ingot) to make a molded into a certain shape, and then re-dissolve the casting and quenched to produce a thin foil. Thereafter, the foil of the thin plate is subjected to a process of shearing, notching, piercing, and washing to complete the filler metal. Next, the filler metal completed through the aforementioned method is attached to the upper and lower surfaces of the separator plate for the heat exchanger, respectively.

In this case, the filler metal is a nickel (Ni) -chromium (Cr) -based material having a lower melting point than the cooling fin or the separating plate and excellent bonding force between metals. Nickel is a main component and chromium, boron (B), and silicon (Si) 7.0%, 3.0% and 4.1% respectively.

Thereafter, the above-described separation plate and the cooling fins are alternately stacked by about 30 sheets to form an assembly of the cooling fins and the separator. At this time, since the filler metal may slide out between the cooling fins and the separating plate, the bonding position may be separated, and after the cooling fins and the separating plate are stacked in a predetermined amount, the assembly of the cooling fins and the separating plate may be grasped by using the fixing jig. give.

The fixing jig serves to prevent the filler metal from slipping off by fixing the assembly of the cooling fins and the separating plate so that uniform pressure is applied across the entire surface during the fixing. In addition, the fixing jig also performs a function of preventing the form or the shape of each other during the transfer or bonding of the cooling fins and the separation plate.

Thereafter, the assembly of the cooling fins and the separator plate is transferred to a vacuum furnace or hydrogen and brazed. In this case, when the assembly of the cooling fins and the separator plate is heated in the vacuum furnace or the hydrogen furnace, filler metals formed on the upper and lower surfaces of the separator plate are melted and are raised along the wall surface of the cooling fin by capillary action.

Thereafter, the melt of the filler metal and the cooling fins react with each other to dissolve a portion of the surface of the cooling fins, and then the melt of the filler metal is diffused toward the cooling fins so that isothermal coagulation occurs so that the cooling fins and the separator are integrally bonded.

Thereafter, the assembly of the cooling fins and the separator plate formed integrally through the brazing joint is taken out from the vacuum furnace or the hydrogen furnace.

However, in the conventional brazing method as described above, a plurality of processes are required to insert and form the filler metal between the separating plate and the cooling fin after the filler metal is processed separately, as well as the cooling fin and the separating plate and the filler metal. Deviation and deformation occurred due to the gap between and the uniform bonding interface and joint strength could not be obtained.

In addition, since filler metal is formed on the upper and lower front surfaces of the separator plate, expensive filler metal is excessively used to waste materials, and the filler metal is used for unnecessary parts, that is, parts that become heat exchange passages other than the joints. As a result, the heat exchange rate is lowered and the thickness of the separator is uneven to reduce the flow rate of the refrigerant.

In addition, a separate fixing jig is required to hold the assembly of the cooling fins and the separating plate, and a considerable processing technique is necessary to process the fixing jig, which makes the peripheral device complicated and of course the effort and cost required for this. There was an increasing problem.

In addition, even if the holding jig is used to hold the assembly of the cooling fins and the separator, the filler metal dissolves during brazing bonding, causing volume expansion, thereby completely preventing the assembly of the cooling fins and the separator from being warped or deformed. There were no drawbacks.

Here, in order to remove the inconvenience caused by the use of the fixing jig described above, the filler metal may be prepared by mixing the alloying element powder and the organic binder to form a liquid adhesive. Filler metal in the liquid state made in this way is applied to the upper and lower surfaces of the separator plate using a screen printer, respectively, and then the cooling fins and the separator plate in the form of adhering the cooling fins to the separator.

However, this also has many problems, that is, poor bonding because the organic binder contained in the liquid filler metal melts and generates bubbles when brazing the assembly of the cooling fin and the separator plate in a vacuum furnace or a hydrogen furnace. There was a problem brought about.

On the other hand, Korean Patent Publication No. 274039 discloses a filler metal electrolessly coated to a predetermined thickness only at a portion of the upper and lower surfaces of a conventional heat exchanger separating plate that is joined to a cooling fin, and then alternates the cooling fin and the separating plate. The method of joining between the plates for heat exchangers has been registered, which is formed by laminating by means of brazing bonding and integrally forming them.

This pre-registered invention prevents the filler metal from overflowing to the non-bonded surface during brazing bonding to secure the uniformity and bonding strength of the bonding interface and to prevent the separation and deformation caused by the gap between the cooling fins and the separating plate and the filler metal. It is obvious that it can be useful in its own way.

However, since the registration invention coats the filler metal only on the upper and lower surfaces of the separator plate in contact with the cooling fins, it requires considerable technical skills and requires a lot of time and effort to coat the contact surface. Not only is it shorter than in the related art, but also expensive filler metal is used to increase the price of the product as in the prior art.

In particular, the registration of the invention, if the filler metal is incorrectly coated on the upper and lower surfaces of the separator, the separator and the cooling fins are not bonded to each other during the brazing operation, the defective product will occur frequently.

Therefore, an object of the present invention for solving the above problems is to add a plate-type heat exchanger to the nickel plating method and the paste coating method to remove the leakage caused by the limit by increasing the amount of the paste by applying the limit portion of the nickel plating method. And a brazing method of a heat exchanger which does not require the use of an expensive filler metal by brazing, and a heat exchanger brazed by the above method.

Another object of the present invention is to provide a brazing method of a heat exchanger which does not generate bubbles during a brazing operation and a heat exchanger brazed by the above method.

Another object of the present invention is to provide a method for implementing a low cost brazing operation.

The present invention for achieving the object as described above, in the heat exchanger consisting of a cooling fin and a separation plate, the process of nickel plating on the upper and lower surfaces of the separation plate, by alternately stacking the separation plate and the cooling fin After the assembly is formed, it is heated to a brazing joint in three steps, and the natural brazing of the brazed assembly, followed by quenching with gas again.

In addition, the present invention is characterized in that it further comprises the step of applying a paste binder on the corners of the separator after plating nickel on the upper and lower surfaces of the separator.

The present invention for achieving the object as described above, in the heat exchanger consisting of a cooling fin and a separation plate, the process of applying a paste binder, the main component of nickel on the upper and lower surfaces of the separation plate, and the separation plate and cooling Forming an assembly by alternately stacking the pins and then heating the brazing joints in three steps, and the natural cooling of the brazed assembly and then quenching it again with gas.

The heating step for the brazing bonding is the first step of heating for 5 to 60 minutes at 200 ~ 800 ℃, the second step of heating for 5 to 60 minutes at 500 ~ 1100 ℃, 10 ~ 90 at 800 ~ 1400 ℃ And a third step of heating for minutes.

Hereinafter, a preferred embodiment according to the present invention will be described in detail.

On the other hand, the brazing method according to an embodiment of the present invention described below will propose a brazing method that is limited to the plate-type heat exchanger, but it is obvious that the bar proposed in the present invention can be equally applied to all heat exchangers.

First, the brazing method of the heat exchanger according to the present invention does not use a foil-type filler metal, which is an expensive solvent in brazing a conventional plate heat exchanger, and is a nickel plating type or paste coating type operation. By adopting the method, it is possible to improve the workability and efficiency and to perform the brazing operation at a low price.

Meanwhile, in the present invention, the brazing bonding method of the heat exchanger will be described by two methods, preferably nickel plating on the upper and lower surfaces of the separator plate, followed by heat melting through three steps, followed by natural cooling and quenching again. Method (hereinafter referred to as "nickel plating method"), and a paste binder containing nickel as a main component on the upper and lower surfaces of the separator plate, followed by heating and melting in three steps, followed by natural cooling and quenching (hereinafter referred to as "nickel plating method"). &Quot; paste coating method "

In the present invention, the brazing by applying a separate paste binder on each corner after plating nickel on the upper and lower surfaces of the separation plate in order to eliminate the risk of the heat exchanger during the brazing operation, that is, leakage occurs. It also suggests how.

At this time, the above-mentioned brazing bonding is heated and melted in three stages, preferably heat-melted in steps up to 200 ~ 1400 ℃ and naturally cooled to 700 ~ 900 ℃ is the reason that the air bubbles during brazing operation to suppress the bonding This is to prevent defects and especially to prevent deformation of the separator and cooling fins. Here, in the heating conditions, the heating time is somewhat different depending on the thickness of the heat exchanger (the number of stacked plates), the heating temperature is always constant regardless of the thickness of the heat exchanger. In addition, the natural cooling temperature is ideally 800 ℃. However, the above-described heating conditions (heating temperature and time and cooling temperature) may vary to some extent depending on the structure and performance of the heat exchanger, which will be within the technical scope of the present invention.

On the other hand, the present inventors have purchased and used a paste binder (trade name: Nickel Binder) developed by "S-D Heater EXCZER" when brazing a heat exchanger by the paste coating method mentioned above.

Hereinafter, the present invention will be described in detail based on the preferred embodiment of the present invention, but the present invention is not limited to the embodiments.

Example 1

First, as described above, the cooling fins and the separating plate, which are components of the heat exchanger, are processed by sequentially processing shaling, notching, drawing, tropping, piercing, and washing, and then nickel on the upper and lower surfaces of the separating plate. After plating, the plated separators and the cooling fins were alternately stacked to form a heat exchanger assembly. In this case, the stacked water may vary depending on the type of heat exchanger.

Thereafter, the heat exchanger assembly was placed in a heating chamber, and then fixed with a jig, followed by heating and melting in three steps. That is, the assembly was heated at 700 ° C. for 50 minutes and then heated at 1000 ° C. for 50 minutes, and then heated again at 1300 ° C. for 70 minutes to completely melt the nickel plated on the separator.

Thereafter, the heat exchanger assembly which passed through the above-described process was naturally cooled to 900 ° C., and then quenched again to 70 ° C. with nitrogen gas, and then the product (heat exchanger) was taken out.

Example 2

First, the cooling fins and the separating plate, which are the components of the plate-type heat exchanger, are processed by sequentially performing shaling, notching, drawing, tropping, piercing, and washing, and then nickel is applied to the upper and lower surfaces of the separating plate. After applying the paste binder as a main component, the separator and the cooling fins were alternately stacked to form a heat exchanger assembly.

Thereafter, the heat exchanger assembly was placed in a heating chamber, fixed with a jig, and then heated at 700 ° C. for 40 minutes, and then heated at 1000 ° C. for 40 minutes, and then again heated at 1000 ° C. for 60 minutes. The paste binder applied to the separator was completely melted.

Thereafter, the heat exchanger assembly which passed through the above process was naturally cooled to 800 ° C., and then quenched again to 50 ° C. with nitrogen gas, and then the product (heat exchanger) was taken out.

Example 3

In the above process, the cooling fins and the separation plate, which are components of the heat exchanger, are respectively processed, and then nickel plating is applied to the upper and lower surfaces of the separation plate. Next, a paste binder was applied to each corner portion of the nickel plated separator, preferably a leak generating portion, and the separators and the cooling fins were alternately stacked to form a heat exchanger assembly.

Thereafter, the heat exchanger assembly was placed in a heating chamber, and then fixed with a jig, followed by heating and melting in three steps. That is, the assembly was heated at 600 ° C. for 40 minutes, then heated at 1000 ° C. for 50 minutes, and then heated again at 1200 ° C. for 80 minutes to completely melt the nickel plated on the separator.

Thereafter, the heat exchanger assembly which passed through the above-described process was naturally cooled to 900 ° C., and then quenched again to 70 ° C. with nitrogen gas, and then the product (heat exchanger) was taken out.

As described above, the present invention does not require the use of expensive filler metal when brazing the heat exchanger, so that the plate heat exchanger can be operated in a high vacuum brazing furnace at a low price and is superior to the pre-registered invention in terms of workability and efficiency. It can be seen.

And the present invention has the advantage of reducing the production cost of the heat exchanger by brazing by adopting a low-cost electroplating method without using the expensive electroless plating method implemented in the pre-registered invention.

In addition, the present invention can prevent deformation of the heat exchanger without generating bubbles during the brazing operation, and in particular, the phenomenon that the separation plate and the cooling fins are not bonded during the brazing operation does not occur, so that a defective product is not produced and a high quality heat exchanger can be produced. That has a synergistic effect.

Claims (6)

In the brazing method of a heat exchanger consisting of a cooling fin and a separation plate, Nickel plating on upper and lower surfaces of the separator; Forming an assembly by alternately stacking the separator and the cooling fins, and then heating and brazing the same in three steps; And naturally cooling the brazed assembly and then quenching it again with gas. The method of claim 1, further comprising applying a paste binder to the corner portion of the separator after the nickel plating.  In the brazing method of a heat exchanger consisting of a cooling fin and a separation plate, Applying a paste binder containing nickel as a main component on the upper and lower surfaces of the separator; Forming an assembly by alternately stacking the separator and the cooling fins, and then heating and brazing the same in three steps; And naturally cooling the brazed assembly and then quenching it again with gas. delete delete A heat exchanger brazed by the method of any one of claims 1 to 3.