Method for producing a heat exchanger

Patent metadata

Field	Value
Publication number	US-2018305820-A1
Application number	US-201815961810-A
Country	US
Kind code	A1
Filing date	Apr 24, 2018
Priority date	Apr 25, 2017
Publication date	Oct 25, 2018
Grant date	—

Abstract

A method for producing a heat exchanger having at least one cooling line with a lightweight metal base through which a water-based coolant can flow may include passivating a surface of the at least one cooling line, which is in contact with the coolant, before the at least one cooling line is filled with the coolant.

First claim

1 . A method for producing a heat exchanger having at least one cooling line with a lightweight metal base, through which a water-based coolant can flow, comprising passivating a surface of the at least one cooling line which is in contact with the coolant, before the at least one cooling line is filled with the coolant.

2 . The method according to claim 1 , wherein passivating the surface is carried out in such a manner that an electrical input conductivity of the coolant increases by less than 100 μS/cm during operation.

3 . The method according to claim 1 , wherein passivating the surface is carried out by a chemical treatment with a passivation solution constituted on the basis of one of an aqueous sulphuric acid solution or an organic acid solution.

4 . The method according to claim 3 , wherein the passivation solution contains at least one of (i) at least 0.1-1 wt % sebacic acid, (ii) at least 20-50 wt % zirconium carbonate, and (iii) 0.05-0.5 wt % triethanolamine.

5 . The method according to claim 3 , wherein the passivation solution includes at least one corrosion inhibitor, which makes up 0.005-10 wt % of the passivation solution.

6 . The method according to claim 5 , wherein the at least one corrosion inhibitor is selected from the following group of chemical compounds: pyrocatechol-3,5-disulphonic acid disodium salt, diethylenetriamine-penta-acetic acid, 8-hydroxy-(7)-iodo-quinoline-sulphonic acid-(5), 8-hydroxy-quinoline-5-sulphonic acid, mannitol, 5-sulphosalicylic acid, aceto-O-hydroxamide acid, norepinephrine, 2-(3,4-dihydroxyphenyl)-ethylamine, L-3,4-dihydroxyphenyl alanine (L-DOPA), 3-hydroxy-2-methyl- pyran-4-oη), citrates, carboxylates, alkaline salts of stearate and/or formiate and/or glyconate, and inorganic inhibitors such as sodium tetraborate, pyrophosphoric acid, calcium gluconate.

7 . The method according to claim 1 , further comprising prewarming the at least one cooling line before passivating the surface.

8 . The method according to claim 3 , further comprising prewarming the passivation solution and then introducing the passivation solution into the at least one cooling line.

9 . The method according to claim 7 , wherein a temperature of the passivation solution is below a temperature of the at least one cooling line.

10 . The method according to claim 1 , wherein a reaction time during which passivating the surface takes place lasts for 0.5-3 hours.

11 . The method according to claim 1 , further comprising pretreating the surface with a first pretreatment before passivating the surface, the first pretreatment including a pickling treatment with an alkaline solution.

12 . The method according to claim 11 , wherein the alkaline solution has a pH value from 8-9 and is heated to a temperature of 40-60° C.

13 . The method according to claim 11 , further comprising pretreating the surface with a second pretreatment after the first pretreatment, the second pretreatment including a pickling treatment with an acid mixture including at least one of sulphuric acid and phosphoric acid.

14 . The method according to claim 13 , wherein the acid mixture contains at least 1-5 wt % of the at least one of sulphuric acid and phosphoric acid, and is 95-99 wt % demineralised.

15 . The method according to claim 13 , wherein the acid mixture contains 50-1000 ppm free fluorides.

16 . The method according to claim 1 , carrying out multiple rinsing cycles of the surface of the at least one cooling line with demineralised water after at least one of the first pretreatment, the second pretreatment, and passivating the surface.

17 . A heat exchanger comprising at least one cooling line, the heat exchanger being produced by the method of claim 1 .

18 . The method according to claim 2 , wherein the electrical input conductivity of the coolant increases by less than 200 μS/cm.

19 . The method according to claim 3 , wherein the one of an aqueous sulphuric acid solution or an organic acid solution has a pH value 2.6.

20 . The method according to claim 7 , wherein the at least one cooling line is prewarmed to 90° C.-120° C.

Assignees

• Mahle Int Gmbh

Inventors

• Englert Peter
• Gebauer Thomas

Classifications

• F28F2245/02

  hydrophilic · CPC title

• C23C22/46 Primary

  containing oxalates · CPC title

• C23C22/78

  Pretreatment of the material to be coated · CPC title

• F28F13/18

  by applying coatings, e.g. radiation-absorbing, radiation-reflecting; by surface treatment, e.g. polishing · CPC title

• F28F19/00

  Preventing the formation of deposits or corrosion, e.g. by using filters {or scrapers} · CPC title