JPH01208696A - Heat exchanger - Google Patents

Abstract

PURPOSE:To restrain the proliferation of microbe which utilize the constituents of lubricating oil as one cause of their proliferation, by a method wherein an aluminum alloy material, formed with a film, is worked by a press utilizing lubricating oil mixed with anti-fungas agent and/or microbicide, thereafter, a heat exchanger is assembled. CONSTITUTION:The principal constituent of a lubricating oil is paraffin series hydrocarbon and/or naphthalene series hydrocarbon and anti-fungas agent, having an affinity with said hydrocarbon and dispersed or resolved sufficiently in said hydrocarbon, such as O-phenylphenol, thiapentazole, potassium sorbic acid, ethyl p-hydroxybenzoate or the like example, is mixed with the lubricating oil. An inorganic acid film is formed on the surface of the aluminum alloy member, fins are manufactured untilizing the lubricating oil, in which 2% O- phenyulphenol is contained, and copper tubes are inserted whereby the core of a heat exchanger is manufactured. After degreasing treatment, cooling operation is effected and the proliferation of microbe has not been recognized.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to various types of heat exchangers, such as heat exchangers for home appliance heating and cooling equipment or automobiles.

[Prior art and its problems]

A heat exchanger made of aluminum or an aluminum alloy (hereinafter simply referred to as an aluminum alloy) is manufactured by forming an inorganic, organic, or composite film on the surface of the aluminum alloy material, which has good water wettability and corrosion resistance, and is coated with this precoat. The aluminum alloy material on which the above-mentioned film has been formed through the process is subjected to press work such as a draw press, the fins are tilted by this press work, and then a copper tube or an aluminum tube is inserted into the fins, In addition, the heat exchanger is assembled by carrying out operations such as pipe expansion (first assembly process), and after this first assembly process, the lubricating oil (press oil) used in the press working process is applied to the fin surface. After the heat exchanger has been assembled in this way, the heat exchanger is degreased with trichlorethylene, etc., and brazed after the degreasing process (second assembly process). For example, various tests such as a submersion leak test are performed, and after these tests, the product is left to stand naturally at room temperature or dried at a temperature below 100°C, and water droplets adhering to the surface are removed during tests such as a submersion test. ing. In such heat exchangers, conventional methods were used to improve the water wettability of the fin surface of the heat exchanger core in order to improve the heat exchange efficiency of the heat exchanger, reduce ventilation resistance, and reduce defrosting energy. Many techniques have been proposed for applying hydrophilic substances such as various surfactants and hydrophilic 1T machine resins to the film surface of pre-coated fin materials. I realized that there were still problems whose contents were completely different from the actual problems. That is, the inventor of the present invention found that in the heat exchanger as described above, many microorganisms such as mold and bacteria grow in the drain receptacle of the heat exchanger, and that bad odors are generated due to this. This led to the realization of problems such as the fact that there are cases in which the

[Disclosure of the invention]

The present inventor discovered an extremely interesting phenomenon while pursuing research aimed at further improving the microbial resistance of heat exchangers. In other words, although the surface film of the fins incorporated in the heat exchanger should have been formed uniformly, the microbial resistance varies depending on the position of the heat exchanger core. They discovered that there are areas where this occurs more often and areas where it occurs less. More specifically, they discovered that the brazing in the heat exchanger core has particularly excellent microbial resistance (low generation of microorganisms) in the vicinity. At the initial stage of the discovery of this phenomenon, it was thought that the above-mentioned variations were due to variations in the surface treatment of the aluminum alloy, but as the research progressed, it was thought that the above-mentioned variations were due to variations in the surface treatment. It turned out that it wasn't a thing. Additionally, the part of the heat exchanger core near the brazing area has particularly good microbial resistance because it adheres to the film due to the heat (temperature) during the brazing process during the assembly process of the heat exchanger. It was thought that this was due to the sterilization of microorganisms, but this idea gradually turned out to be wrong. That is, as a first step, the heat exchanger is formed into fins by draw-pressing or drawless-pressing an aluminum alloy material on which an organic film and/or an inorganic film is formed. In addition, in this press working process, paraffinic hydrocarbon (Cnl12n+2) or naprane hydrocarbon (Cnl12n+2)
n II 2n ) as the main component, for example 50:5
0, 30.70 or 70:30, and has an average molecular weight of about 100 to 500 and an average carbon number of about 10 to 30;
A lubricating oil (basically, it inevitably contains 11,000 pp or less of water) having a viscosity (40° C.) of about 2 to 20 cst is used. Then, a copper tube, for example, is inserted into the fins obtained by the above-mentioned press processing and expanded to produce a predetermined heat exchanger core. After this, the lubricating oil used in the pressing process is removed from the fin surface with a degreasing agent such as perchlorethylene, trichlorethylene, trichloroethane, etc. After the lubricating oil is removed, the copper U-bend (joint pipe) is brazed. has been done. However, as a result of the inventor's research, it has been discovered that although most of the lubricating oil is removed by the degreasing process using the degreasing agent, the lubricating oil is not completely removed. There was some lubricating oil left behind. In other words, although it was believed that the previous degreasing treatments were sufficient and that virtually no lubricating oil remained after degreasing, it is believed that the removal of lubricating oil by conventional degreasing treatments is complete. It was confirmed that this could not be said. When a copper U-bend is being soldered, the surface of the fin near the U-bend will of course be heated to some extent, and this heat will cause the lubricating oil to run off in the area near the U-bend. Furthermore, it was found that the lubricating oil remained incompletely removed in the portion far from the U-bend because it was less likely to be heated. In other words, there is no doubt that the difference in microbial resistance depending on the position of the heat exchanger core is due to the effect of heating.This is not due to the sterilization effect, but rather due to the various interfaces provided to the precoat film. An emulsion consists of three substances: a hydrophilic substance such as an activator and a hydrophilic organic resin, a lubricating oil remaining on the surface of the fin and/or in the gap between the fin and the tube after degreasing with an organic solvent, and water condensed on the surface of the fin. It was found that when the lubricating oil flows down to the drain receptacle, the lubricating oil that flows down plays a large role in the growth of microorganisms in areas where there is a large amount of oil present in the emulsion, and as a result, there is a large number of microorganisms. be. The present invention was made as a result of elucidation of such a unique phenomenon that no one has noticed until now, and it is extremely difficult to completely remove the lubricating oil used in press working. Considering that it is extremely difficult to completely remove lubricating oil remaining in the gaps between the fins and tubes, it is recommended that lubricating oil and antibacterial and/or bactericidal agents coexist in the heat exchanger, especially for aluminum alloys. Antibacterial agents and/or lubricants remain in the lubricating oil used when pressing materials into fins, especially in the gaps between the fins and tubes of heat exchangers and/or on the surfaces of the fins. A heat exchanger is provided in which a disinfectant is present. It is preferable that at least one of the antibacterial agent and/or bactericidal agent used suppresses the growth of microorganisms whose growth factor is the lubricating oil component. Furthermore, antibacterial agents and/or bactericidal agents have a high affinity with lubricating oil, and it is desirable that the antibacterial agent and/or bactericidal agent be sufficiently dispersed or dissolved in the lubricating oil. If the agent and/or bactericide are not sufficiently dispersed or dissolved in the lubricant, they may wear out the press die during press processing or cause the lubricant to deteriorate. When applying the lubricant to pre-coated aluminum alloy material, if the bactericide etc. is precipitated in particles, the lubricant will not be applied to the surface of the aluminum alloy material in those areas, and the purpose of the lubricant application will not be achieved. Moreover, the condensed water that has become an emulsion and the lubricating oil that contains the antibacterial agent or bactericide become difficult to flow down to the drain tray, and the antibacterial agent or bactericide cannot fully perform its purpose. It almost disappears. Such antibacterial and bactericidal agents include benzoic acid,
9. Aromatic carboxylic acids and their salts such as sodium chloride, cinnamic acid, sorbic acid, potassium sorbate, dehydroacetic acid, sodium dehydroacetate, 10. Fats such as pionic acid, sodium propionate, calcium propionate, etc. Carboxylic acids and their salts, isobutyl paraoxybenzoate, paraoxy branch, isopropyl fragrant, ethyl paraoxybenzoate, propyl paraoxybenzoate, butyl paraoxybenzoate and other esters, cresol, thymol, eugenol, or-1 phenylphenol, Phenols such as phenylphenol and dihydroxyphenyl, acid amides such as N-fluoro-dichloromethyl-thio-cyclohexene-carboximide, N-trichloromethyl-mercaptophthalimide, N-fluorodichloromethyl-mercaptophthalimide, ortho Nitrobenzenesulfamide, N,N'-dimethyl N'
-phenyl-(N'-fluorodichloromethyl-thio-)
-Sulfamides such as sulfamide, 2-(methoxy-
carbonyl-amino)-benzimidazo-1,2-(
Molecular salts of methoxy-carbonyl-amino-)benzimidazole and dodecylbenzenesulfonic acid, imidazoles such as thiabendazole, etc. can be used, and aromatic carboxylic acids or salts thereof have an average molecular weight of about 100 to
250, with an average carbon number of about 5 to 12, and
Average molecular weight for aliphatic carboxylic acids or salts thereof: approximately 90
-250, with an average carbon number of about 8-15; as esters, those with an average molecular weight of about 150-250 and with an average carbon number of about 8-15 are preferred; and as phenols, those with an average molecular weight of about 90 ~300, average carbon number approximately 6
The average molecular weight of acid amides is preferably about 120 to 500, the average carbon number is about 8 to 20, and the average nitrogen number is about 1 to 5. As sulfamides, those with an average molecular weight of about 150 are preferable. ~500, average carbon number approximately 5~
20, the average nitrogen number is preferably about 1 to 6, the average sulfur number is about 1 to 3, and the imidazoles have an average molecular weight of about 1.
00-400, average carbon number approximately 3-30, average nitrogen number approximately 2
~4 is preferable, and this amount is not uniquely determined depending on the composition, viscosity, etc. of the lubricating oil, or
It is added to the lubricating oil at a concentration of usually 0.01 to 5%, more preferably about 0.3 to 2%. In addition, as lubricating oils, those based on paraffin (CnHl''z) and napuran (Cnl12n) type hydrocarbons are used, and the average number of carbon atoms is about 10 to 30.
The average molecular weight is about 100-500, and its viscosity (40℃)
is preferably about 2 to 20 cst, and the amount of lubricant applied to the surface of the aluminum alloy material is about 5 to soo
. It is desirable that it be about mg/n2. Incidentally, an anti-wear additive or the like may be added to the lubricating oil. In addition, the film formed on the surface of the aluminum alloy material in the pre-coating process includes, for example, an anodized film, a boehmite-based film, a film treated with boehmite or a film treated with silicate after anodization, a film treated with silica sol, and a film treated with silicate after chromate treatment. Acid-treated film, silicate-coated film, film with silica sol aqueous solution, or JP-A-58-10
There are inorganic coatings such as those produced in a bath containing an oxidizing agent as disclosed in Publication No. 6397, hydrophilic organic resin coatings, or composite coatings of these. 1 to 30 B/m''. Also, a small amount, for example, about 2 B/da'' or less, of an inorganic phosphate, a surfactant, or a hydrophilic organic substance may be interposed in the above-mentioned film. .

[Example 1] JIS 1200-H28 aluminum alloy material was immersed in a sodium hypochlorite aqueous solution at a temperature of about 85°C,
Next, it is immersed in a water glass solution to form an inorganic oxide film with good water wettability on the surface. Then, on the surface of the oxide film-formed aluminum alloy material,
Apply an aqueous solution of sodium tripolyphosphate and polyoxyethylene nonyl phenyl ether to adhere an inorganic phosphoric acid compound and a nonionic surfactant. Then, the aluminum alloy material on which the inorganic film with the inorganic phosphoric acid compound and nonionic surfactant was formed was coated with a lubricating oil (Finstock Oil A manufactured by Showa Shell Sekiyu Co., Ltd.) with a kinematic viscosity of 40°C. ) 7 to 8 cst) in which an antibacterial agent, ol-1 to phenylphenol, was dispersed to a concentration of 2%, and a drawless press process, mainly ironing, was performed to obtain fins. Next, a copper tube is inserted into the fin and expanded to produce a heat exchanger core. Then, in order to remove the lubricating oil deposited during the drawless press processing from the thus assembled heat exchanger core, a degreasing treatment using trichlorethylene is performed under normal conditions. After this degreasing treatment, the copper U-bend is brazed. The core of the heat exchanger assembled as described above was installed in the evaporator (indoor unit) of the projector, and continuous cooling operation was performed for 4 hours, and the condensed water was collected to examine the growth of microorganisms. As a result, although it was observed that the lubricating oil remaining in the gap between the fin and the tube was flowing down, almost no growth of microorganisms due to this flowing down lubricating oil was observed.

Example 2 A heat exchanger was obtained by carrying out the same procedure as in Example 1 except that ethyl paraoxybenzoate was used as the antibacterial agent. The core of the heat exchanger assembled as described above was installed in the evaporator (indoor unit) of the projector, and continuous cooling operation was performed for 4 hours, and the condensed water was collected to examine the growth of microorganisms. As a result, although it was observed that the lubricating oil remaining in the gap between the fin and the tube was flowing down, almost no growth of microorganisms due to this flowing down lubricating oil was observed.

Example 3 A heat exchanger was obtained in the same manner as in Example 1 except that potassium sorbate was used as the antibacterial agent. The core of the heat exchanger assembled as described above was installed in the evaporator (indoor unit) of the projector, and continuous cooling operation was performed for 4 hours, and the condensed water was collected to examine the growth of microorganisms. As a result, although it was observed that the lubricating oil remaining in the gap between the fin and the tube was flowing down, almost no growth of microorganisms due to this flowing down lubricating oil was observed.

Example 4 A heat exchanger was obtained by carrying out the same procedure as in Example 1 except that dehydroacetic acid was used as the antibacterial agent. The core of the heat exchanger assembled as described above was installed in the evaporator (indoor unit) of the projector, and continuous cooling operation was performed for 4 hours, and the condensed water was collected to examine the growth of microorganisms. As a result, although it was observed that the lubricating oil remaining in the gap between the fin and the tube was flowing down, almost no growth of microorganisms due to this flowing down lubricating oil was observed.

Example 5 A heat exchanger was obtained by carrying out the same procedure as in Example 1 except that thiabendazole was used as the antibacterial agent. The core of the heat exchanger assembled as described above was installed in the evaporator (indoor unit) of the projector, and continuous cooling operation was performed for 4 hours, and the condensed water was collected to examine the growth of microorganisms. As a result, although it was observed that the lubricating oil remaining in the gap between the fin and the tube was flowing down, almost no growth of microorganisms due to this flowing down lubricating oil was observed.

[Example 6] In Example 1, an aluminum alloy material on which an inorganic film with an inorganic phosphoric acid compound and a nonionic surfactant was formed was used, and the antibacterial agent used in Example 1 was used during drawless press processing. A heat exchanger is obtained by applying dispersed lubricating oil to the surface of an aluminum alloy material, and otherwise performing the same procedure. The core of the heat exchanger assembled as described above was installed in the evaporator (indoor unit) of the projector, and continuous cooling operation was performed for 4 hours, and the condensed water was collected to examine the growth of microorganisms. As a result, although it was observed that the lubricating oil remaining in the gap between the fin and the tube was flowing down, almost no growth of microorganisms due to this flowing down lubricating oil was observed.

[Comparative Example 1] A heat exchanger was obtained by carrying out the same procedure as in Example 1 without using any antibacterial agent. The core of the heat exchanger assembled as described above was installed in a convex evaporator (indoor fi>), and continuous cooling operation was performed for 4 hours, and the condensed water was collected to examine the growth of microorganisms. As a result, many microorganisms were found, which appeared to be caused by the lubricating oil that had flowed down.

[Comparative Example 2] In the same manner as in Example 1, using an aluminum alloy material provided with a hydrophilic polyimide resin coating instead of the inorganic oxide coating, and without using any antibacterial agent, the heat exchanger 1:). Place the heat exchanger core assembled as described above into an actual evaporator indoors. 1), continuous cooling operation was performed for 4 hours, and the condensed water was collected to examine the growth of microorganisms. As a result, a large number of microorganisms were observed, which appeared to be caused by the lubricating oil that had flowed down. [Comparative Example 3] In Example 1, instead of the inorganic oxide film, an aluminum alloy material was used, which was provided with a coating obtained by applying a polyimide resin paint in which the antibacterial agent of Example 1 was dispersed, and A heat exchanger is obtained in the same manner using a lubricating oil in which no antibacterial agent is dispersed.

Claims (1)

[Scope of Claims] 1. A heat exchanger characterized in that a lubricating oil and an antibacterial agent and/or a bactericidal agent coexist in the heat exchanger. 2. The heat exchanger according to claim 1, in which the antibacterial agent and/or bactericidal agent is present together with the lubricating oil present in the gap between the fins and tubes of the heat exchanger and/or on the fin surface. . 3. In the heat exchanger according to claim 1, the aluminum or aluminum alloy material on which the organic film and/or inorganic film is formed is pressed using a lubricating oil mixed with an antibacterial agent and/or a bactericidal agent. A product made by assembling the products obtained by the press processing. 4. The heat exchanger according to claims 1 to 3, which is based on a lubricating oil or a paraffinic/and/or naprane hydrocarbon. 5. The heat exchanger according to claims 1 to 3, in which at least one of the antibacterial agent and/or the bactericidal agent suppresses the growth of microorganisms whose growth factor is a lubricating oil component. 6. In the heat exchanger according to claims 1 to 3, the antibacterial agent and/or bactericidal agent has a high affinity with the lubricating oil, and the antibacterial agent and/or bactericidal agent is sufficiently contained in the lubricating oil. Something that disperses or dissolves. 7. In the heat exchanger according to claim 5 or 6, the antibacterial agent and the bactericidal agent have an average molecular weight of about 100 to 2.
50, aromatic carboxylic acids and salts thereof having an average carbon number of about 5 to 12, average molecular weight of about 90 to 250, average carbon number of about 5 to 1
2 aliphatic carboxylic acid and its salt, average molecular weight approximately 150
-250, esters with an average carbon number of about 8-15, average molecular weight of about 90-300, phenols with an average carbon number of about 6-20, average molecular weight of about 120-500, average carbon number of about 8-
20. Acid amides with an average nitrogen number of about 1 to 5, average molecular weight of about 150 to 500, average carbon number of about 5 to 20, average nitrogen number of about 1 to 6, and sulfamides with an average sulfur number of about 1 to 3, average molecular weight At least one imidazole selected from imidazoles having about 100 to 400 carbon atoms, an average carbon number of about 3 to 30, and an average nitrogen number of about 2 to 4.