Method of manufacturing heat exchange sections based on aluminum

 

(57) Abstract:

The invention is intended for use in heat exchangers and methods of use thereof. Method of manufacturing heat exchange sections on the basis of aluminum involves the retention of heat exchanger tubes, formed on the basis of aluminum, and ribs formed from zinc-containing material based on aluminum, spandam state with each other by using the composition for soldering, which is applied on the outer surface of the tubes of the heat exchanger, and then the heat pipe heat exchanger and edges to a predetermined temperature, causing the pipe of the heat exchanger and ribs in spanne relation to each other and forming on the outer surface of the tubes of the heat exchanger mixed diffusion layer, and the pipe of the heat exchanger is made of extruded and flat, composition for soldering obtained from a mixture of silicon and fluoride flux type, and mixed diffusion layer consists of silicon contained in the composition for soldering, and zinc contained in the radiator fins. According to the invention the concentration of zinc in the ribs of the heat exchanger is 1-5%. The invention enables the manufacture of pipe of the heat exchanger, which may be soldered to the ribs and cloud-based aluminium, and method of its production. More specifically, this invention relates to heat exchange sections on the basis of aluminum, in which the flat tube heat exchanger, for example, on the basis of aluminum and the edge of the heat exchanger on the basis of aluminum held in soldered with respect to each other by using a solder composition. The invention also relates to the production of such heat exchange sections.

In General, widely used a particular heat exchanger, based on aluminum, which is constructed with a tube heat exchanger, created from aluminium or aluminium alloy (hereafter called "the aluminum"), and an edge of the heat exchanger on the basis of aluminum, brazed with each other. Additionally and in order to obtain improved characteristics of the heat exchange, is used pressed flat tube in tube heat exchanger, which is obtained from the pressed form, on the basis of aluminum.

To the obtained heat exchanger is protected against corrosion (corrosion resistant), outer surface of the flat tube heat exchanger is covered mainly zinc (Zn), followed by diffusion of Zn on the outer surface of such flat tubes during the soldering temperature and palenoi film, selected from such materials as coated with zinc-containing solder, namely composition for soldering. As a similar example document USA-4831701 describes the way in which an edge of the heat exchanger on the basis of aluminum, is coated on the surface of the solder composition obtained from an alloy of Al-Si, and flux coated Zn, superimposed on a flat tube heat exchanger, and the welded edges of the heat exchanger.

This solder film for use in the manufacture of the ribs of the heat exchanger, however, the road compared to a net material for the fins of the heat exchanger, not covered with solder. Moreover, because the coating its surface with solder solder film leads to rapid abrasion of the working roller manufacturing fin heat exchanger that requires frequent polishing the working roller. As an additional problem tends to occur in outbreaks and noise when working shutters or similar devices with the possible wear of the end section of the heat exchanger. Moreover, according to the method of document USA-4831701 the process of coating compound with Zn induces an increase in the number of steps of the method, and thus, the increase in the cost of production and cost of material.

To improve the corrosion resistance of flat truby way of zincate (galvanizing) or spray coating Zn, and then shaped diffusion layer of Zn in the soldering process, so that the flat tube is protected against corrosion with electrode screen.

However, this method has the problem, namely, that application of Zn rather time-consuming and requires a lot of time.

On the other hand, there is a method that uses pure material for the fins of the heat exchanger, not covered by the solder, and in which a powder of the alloy Al-Si obtained from aluminum (A1) and silicon (Si), to cover the edge of the heat exchanger and solder it with the flat tube heat exchanger.

This known method requires to cover the powder alloy Al-Si in large numbers, and thus causes difficulties associated with the cost and Assembly.

According to another known method, a flat tube heat exchanger is made of electrically welded pipes, covered with material for soldering. For example, document JP 59086899 describes a method for the production of heat exchange sections on the basis of aluminum, including the retention of heat exchanger tubes, formed on the basis of aluminum, and ribs formed from zinc-containing material based on aluminum, spandam state with each other by modulating the abuser heat pipe heat exchanger and edges to a predetermined temperature, lead pipe of the heat exchanger and ribs in spanne relation to each other and forming on the outer surface of the tubes of the heat exchanger mixed diffusion layer.

In this way, however, you want to insert inside of this pipe when running multi-channel system, and it causes an additional process step, and, therefore, increase the cost of production and cost of material.

One objective of this invention is to provide a heat exchange sections, which follows from the use of tubes of the heat exchanger that does not require pre-coating Zn, and pure material for the ribs of the heat exchanger, not covered by the composition of the solder, and which shows the corrosion resistance and the ability to solder, comparable with these characteristics of the conventional equivalent. Another objective of this invention is to provide a method of manufacture of such heat exchange sections.

To solve the above problems created by the production method section of the heat exchanger on the basis of aluminum, including the retention of heat exchanger tubes, formed on the basis of aluminum, and ribs formed from zinc-containing material based on aluminum, spandrel heat exchanger, and then the heat pipe heat exchanger and edges to a predetermined temperature, causing the pipe of the heat exchanger and ribs in spanne relation to each other and forming on the outer surface of the tubes of the heat exchanger mixed diffusion layer, in which, according to the invention, the pipe of the heat exchanger is made of extruded and flat, the composition for soldering obtained from a mixture of silicon and fluoride flux type, and mixed diffusion layer consists of silicon contained in the composition for soldering, and zinc contained in the fins of the heat exchanger.

In this example, mixed diffusion layer consisting of silicon and zinc and located on the surface of the heat exchanger, the maximum concentration of silicon is in the range of 0.5-1.5% of zinc - 0,4-3,0%.

In the present invention, the pipe of the heat exchanger may be of any shape because it is made on the basis of aluminum. Preferably this tube can be pressed flat tube on the basis of aluminum, provided with a multitude of passages for supplying teplonasosy environment. In addition, it is desirable that the concentration of zinc in the above heatsink is in the range of 1-5%.

According to the present invention, as is mennica does not require pre-coating Zn, and advantageously can be used pure zinc-containing material for forming the ribs of the heat exchanger, not coated with the composition for soldering. Most of the ribs of the heat exchanger molten composition of the solder during the soldering, that the zinc contained in the fin of the heat exchanger, diffuses through the outer surface of the tubes of the heat exchanger so as to form therein a mixed diffusion layer derived from silicon and zinc.

Therefore, the zinc diffusion layer can be formed on the outer surface of the tubes of the heat exchanger without zinc, which previously was required for the old pipe. This allows you to easily perform a section of the heat exchanger with excellent corrosion resistance and the ability to solder. Also an advantage that the edge of the heat exchanger requires a coating composition for soldering, and thus guaranteed easy formation, and, in addition, it eliminates edges and burrs in the final production section of the heat exchanger of high quality. Additionally achieves improved performance while saving cost.

Brief description of drawings

Fig.1 illustrates a perspective view of important parts of one form t, and, showing each of the elements: the hackneyed phrases of flat tubes and corrugated fin heat exchanger, which embody this invention.

Fig.3, the cross - sectional view showing the manner in which the composition for soldering is applied to the hackneyed phrases of the flat tube in accordance with the invention.

Fig. 4, the cross - sectional view, partially enlarged, of the manner in which the pipe of the heat exchanger and fin heat exchanger soldered to each other in accordance with the invention.

In these drawings, the position 4 is pressed to the flat pipe (pipe heat exchanger), 5 - grooved edge of the heat exchanger, 6 - section, of the heat exchanger 7 to the composition for soldering and 8 - K diffusion layer Si and Zn.

The present invention is described below with reference to the accompanying drawings, in accordance with several examples.

Fig. 1 is a view in the perspective view showing important parts of one form of heat exchanger assembled in the section of the heat exchanger according to the present invention.

The above heat exchanger is constructed with a pair of drainage tubes 3 arranged in opposing spaced positions and having input 1 coolant or input 2 carrier, mnoey are parallel to each other and connected with the drainage pipes 3, and with the ribs of the heat exchanger, such as corrugated ribs located between the stamped flat tubes 4. In the assembled thus the heat exchanger drainage pipe 3 and the extruded flat tubes 4 are formed stamped form on the basis of aluminum, and corrugated fins 5 are formed by bending flat material based on aluminum in alternating recesses and ridges or wavy configuration. The drainage pipe 3, extruded flat tubes 4 and corrugated fins 5 are entirely soldered to each other using solder composition (material for soldering), so the heat exchanger is made.

In this case, the section of the heat exchanger 6, is made of stamped flat tubes 4 and corrugated fins 5, formed such stamped flat tubes on the basis of aluminum (JIS a, for example), which previously has not been coated with zinc, corrugated fin 5 is formed from a flat material based on aluminum containing Zn, not covered with material for soldering. As a material for soldering is widely used a mixture of powdered silicon (Si) powder and fluoride flux type, or a mixture of Si powder, Zn powder and a powder flux fluoride type. Setelan, because it is not similar to the chloride and immune to corrosion with respect to aluminum. The ratio of Si to flux (% by weight) set Si:flux = 1:2.

In order to fabricate the above-mentioned section of the heat exchanger 6, the first step of the method consists in cooking, as seen in Fig.2, extruded flat tubes 4 on the basis of aluminum and the definition of many passages for the flow of coolant, and corrugated fins 5, bent in a wavy structure and containing Zn. To do this, corrugated fins 5 are obtained by bending zinc-containing flat material based on aluminum (for example, JIS A3NO3) in the wave-shaped working rollers. In this case, the working rollers are less prone to wear than in the case of soldering film covering material for soldering. Another advantage is the fact that there was no scuffing, no Burr, even when the shutters or similar devices are produced and installed on the edges. This contributes to the quality of the ribs of the heat exchanger.

Composition for soldering 7 after this is applied to the surface of the stamped flat tubes 4, as shown in Fig.S, through the use of a binder material, such as, for example, thermoplastic acrylic cm, what, for example, by spraying the mixed liquid of the suspension of the binder and composition for soldering or by dipping the pressed flat tubes 4 in a mixed liquid suspension of a binder, and a composition for soldering, and then pulling the pipe vertically from a liquid suspension, so as to remove excess slurry.

Next, the extruded flat tubes 4, loaded thus a composition for soldering, and Zn-containing corrugated fins 5 are combined among themselves and are attached to each other using a tool (not shown) or attached to each other by joining the drainage pipes 3. By further heating up to a predetermined temperature above 590oWith, for example, in a heating furnace or the like, the composition of the solder is melted to lead monotonous flat tube 4 and the corrugated fins 5 in the whole spanne relation to each other. During the operation of the soldering portion of the corrugated fins 5 is melted by exposure of the composition for soldering, and this leads to the fact that Zn contained in the corrugated fins 5, diffuses through the outer surface of the extruded flat tubes 4, finally connecting with Si contained in the composition of the solder during the formation of the diffusion slivajutsja in the whole United state with each other using the rim 9 of the alloy Al-Si-Zn, located between them. Using diffusion layer 8 of Si and Zn formed on the outer surface of the extruded flat tubes 4, the section of the heat exchanger 6 becomes resistant to corrosion.

Below provides an explanation of those experiments that were performed to assess the ability to solder and corrosion resistance of the section of the heat exchanger according to the present invention compared with the corresponding characteristics of the section of the heat exchanger of aluminum based on the previous technique.

raw materials

* extruded flat tubes

(1) material: JIS A1050

JIS A1050 + floor arc spraying of Zn (consumption Zn 8 g/m2)

alloy NE (modified alloy A1050) (composition: 0,05% Si, 0.18% of Fe, 0.4% si, 0.02% of Zn and 0.04% Zr)

(2) shape: outer size (width x thickness) = 19,2 x1,93 mm (one-sided wall thickness: 0.4 mm)

* radiators

(1) material: the raw material (JIS A3NO3 + content of Zn 0-4,0%)

the solder film (A + 1,0% Zn/3NO3 + 1,5% Zn/A4343 + 1,0% Zn)

(2) the form: (width x thickness) = 21,1 x 0.1 mm

* the lineups for soldering

(1) Si powder + powder flux fluoride type + binder

the total number of bonding prophetic is zhota: 40 m3/hour) heating rate: 30oC/min

With regard to comparative samples 1 and 2 and examples 1 to 4, in which the above pressed flat tube 4 was firmly fused with the raw material of the ribs (with a content of Zn 0-4,0%) by using the above composition for soldering, as well as regarding the comparative soldering methods 1 and 2 (current soldering), details of which are shown in the table.1, the connection part between the pressed-flat tube 4 and the ribs were cut and tested. The results ability to solder shown in the table.2.

Further evaluation of corrosion resistance to the final product, the soldering was done using the CASS test (JIS D). The results are shown in table.2.

Moreover, pressed flat tube 4 was tested in a cross-section through the x-ray microanalyzer (RMA), to check the status of diffusion of Zn and Si. The results are shown in table.2.

The above experimental results show that all soldered condition obtained in examples 1-4, a relatively successful for States section of the heat exchanger that uses solder film in the current application, and that the percentage of seal in primeros current soldering 1 and 2, create end-to-end path when the duration time of the test up to 1500 hours, while the products of examples 1-4 are free from such holes even after the expiration of such time checking.

Moreover, the study of the state of diffusion of Zn and Si (surface concentration and diffusion depth), the state of diffusion of Zn in examples 1-4 is equal to 0.6-2.2% and 72-80 μm, and the state of diffusion of Si is 0.8-1.0% and 67-78 microns.

From previous experiments it was found that the section of the heat exchanger obtained from the ribs on the basis of aluminum, having a content of Zn 1,2-4,0%, and pressed flat tubes on the basis of aluminum, which omitted the pre-application of Zn, which were soldered to each other by use of the composition for soldering, composed of a mixture of Si powder and a flux fluoride type, capable of giving ability to solder and corrosion resistance similar to or higher than those of the characteristic sections of the heat exchanger, currently used in the art. Although it is not specifically stated in the aforementioned experimental results, the lower the content of Zn in the material of the heat sink than 1.0%, leads to a concentration of surface diffusion of Zn lower than 0.4%, thus leading to the ial group of fins of the heat exchanger becomes highly susceptible to corrosion, that leads to the final heat exchanger has a shortened service life, and also to the fact that the resulting edge has reduced the strength of the material at high temperatures and because of this tends to bend when soldering. Therefore, when Zn is present in the material of the ribs of the heat exchanger in the ratio of 1.0 to 5.0%, the ability to solder and corrosion resistance reach such values that are equivalent to these characteristics now applicable sections of the heat exchangers or higher.

Although it is not shown in the above experimental results, it was also found that the experimental results that the greater the number of added Zn, the layer of diffusion of Zn can be formed at a higher concentration, and thus, we can expect more corrositivity, and that, since the diffusion layer Si responsive to forming the fossa causing the corrosion potential on the side of the extruded flat tubes, can be achieved a higher corrositivity than in the pressed-flat trumpet, free from the layer of diffusion of Si.

As described and shown here previously, the present invention allows the use of a mixture of silicon is the second zinc, and uncovered material of the ribs of the heat exchanger containing Zn, but not covered with the solder composition may be used in the formation of the ribs. Part of the rib, thus melts under the influence of the solder composition, the zinc contained in the ribs, diffuses to the outer surface of the tubes of the heat exchanger, and thus functions as forming a diffusion layer consisting of a mixture of silicon and zinc, on this outer surface.

Accordingly, the diffusion layer of zinc can be formed on the outer surface of the tubes of the heat exchanger without zinc, previously required in relation to the previous pipe. This, in turn, allows you to easily create a section of the heat exchanger with high corrosion resistance and high ability to solder. Another advantage is that the fins of the heat exchanger does not require solder coating composition, thus ensuring easy machinability, and, moreover, the elimination of burrs and Burr, with the possibility of making heat exchange sections of high quality. As an additional benefit, possible high performance while saving costs.

1. The production method is section of the heat exchanger is formed from zinc-containing material based on aluminum, in spandam state with each other by using the composition for soldering, which is applied on the outer surface of the tubes of the heat exchanger, and then the heat pipe heat exchanger and edges to a predetermined temperature, causing the pipe of the heat exchanger and ribs in spanne relation to each other and forming on the outer surface of the tubes of the heat exchanger mixed diffusion layer, characterized in that the tube of the heat exchanger is made of extruded and flat, the composition for soldering obtained from a mixture of silicon and fluoride flux type, and mixed diffusion layer consists of silicon contained in the composition for soldering, and zinc contained in the fins of the heat exchanger.

2. Method of manufacturing heat exchange sections based on aluminium under item 1, characterized in that the concentration of zinc in the ribs of the heat exchanger is 1-5%.

 

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FIELD: soldering.

SUBSTANCE: invention can be used at soldering of parts manufactured of aluminum and its alloys. Coating is formed by application and heating of hexafluosilicate of alkaline metal. Use is made of pure hexafluosilicate of alkaline metal or mixture of hexafluosilicated of alkaline metal with fluoroaluminate in amount of maximum 5 mass % in terms of used hexafluosilicate of alkaline metal. Coating is applied to article by dry or wet flux application method nonobligatorily with binder or film former. Corrosion-resistant layer of potassium fluoroaluminate formed simultaneously provides effective protection of alloy from subsequent oxidation.

EFFECT: improved quality of soldered joints.

12 cl, 3 ex

FIELD: electric engineering.

SUBSTANCE: carrier body has foil sheets, at least partially profiled, placed in case or enrolled, and then placed in pipe-like cover. Heating of end of honeycomb element is performed at least on separate portions having shape of patches, by means of surface inductor with appropriately placed inductive coils. During heating inductor and/or honeycomb element are set in relative motion, first of all in rotation relatively to each other. It is possible to form connections by baking or soldering with flexible variation of area occupied on end by them. Surface inductor allows effective variation of placement and/or dimensions of connection points formed with it and/or connection areas of patch-like form.

EFFECT: higher efficiency.

2 cl, 3 dwg

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