Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F1/00—Tubular elements; Assemblies of tubular elements
  • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
  • F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
  • F28F1/24—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely
  • F28F1/32—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely the means having portions engaging further tubular elements
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
  • C11D7/22—Organic compounds
  • C11D7/34—Organic compounds containing sulfur
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
  • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
  • C23G1/04—Cleaning or pickling metallic material with solutions or molten salts with acid solutions using inhibitors
  • C23G1/06—Cleaning or pickling metallic material with solutions or molten salts with acid solutions using inhibitors organic inhibitors
  • C23G1/065—Cleaning or pickling metallic material with solutions or molten salts with acid solutions using inhibitors organic inhibitors sulfur-containing compounds
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F22—STEAM GENERATION
  • F22D—PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS
  • F22D1/00—Feed-water heaters, i.e. economisers or like preheaters
  • F22D1/02—Feed-water heaters, i.e. economisers or like preheaters with water tubes arranged in the boiler furnace, fire tubes or flue ways
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
  • F24H1/10—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium
  • F24H1/12—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium in which the water is kept separate from the heating medium

Definitions

• This invention relates to the art of pickling metals and more especially to means for improving the results obtained with acid pickling baths and for preventing the attack of metals by solutions of acid reaction.
• metals and metal alloys are attacked by organic and inorganic acids in the presence of water and especially by aqueous solutions of acids.
• aqueous solutions of acids or acid salts in order to remove scale and impurities on the surface of the treate me a s, not only the scale and impurities are removed; a certain amount of the metal also dissolves under the formation of metal-salts in the bath, involving a loss of active acid.
• One object of the invention is to prevent or minimize the dissolution of metal during pickling and the loss of active acid.
• Another object of the invention is to prevent the attack of metals by acidic solutions in chemical and physical processes wherein such acidic solutions are used in metallic receptacles.
• Another object is to prevent or minimize the contamination of the air with acid particles originating from the bath and carried into the atmosphere by the hydrogen generated during the pickling treatment, the presence of acid particles in the atmosphere being noxious for the workmen.
• Still another object in view is to prevent or minimize the occurrence of gas enclosures in the treated metallic object, such enclosures of gas occurring frequently after pickling processes and being probably due t5 the solution of hydrogen gas developed "by the process in the metallic surface.
• a further object of the invention is to prevent or minimize the brittleness of the treated metal which is usually caused by pickling treatment, caused by the hydrogen in statu nascendi developed in the treatment.
• compositions may be used for the purposes aforesaid, as will be described hereinafter.
• a non-oxidizing acid solution is used with an addition of an inhibitor of the group constituted by the alkyl-thiocyanates and the aralkylthiocyanates.
• aceticand oxalic acid may be successfully used.
• a non-oxidizing mineral acid such as lphuric and hydrochloric acid
• aqueous solutions of acid salts such as sggiium bis ulfa te may be profitably used.
• Inhibitors which appeared to be useful according to this invention are e. g. methylthiocyanate, benzylthi dithiocyano-ethane (NCS-C Hz-SCN), and other alkylor aralkylthiocyanates.
• the protecting action of the thiocyanate contained in the pickling baths can be improved by the addition of capillary active agents, such as wetting agents, and/or foaming agents and/or a er 1 1 o e composion.
• capillary active agents such as wetting agents, and/or foaming agents and/or a er 1 1 o e composion.
• ponine has been found to be a useful addition.
• an inhibitor other than a thiocyanate for instance thiocarbanilide, appears to improve the inhibiting action of the thiocyanate and also the inhibiting action of the additional inhibitor.
• the thiocyanates have been found to also improve the properties of protective coatings serving to prevent corrosion of metals.
• the dimensions of the iron pieces were about 4.0 to 2.5 to 0.1 cm., their weight averaged 5-6 grams.
• the pieces were immersed in the solutions and under the conditions mentioned in the examples.
• Example 1 Example IX cid-. no! n01. Acid 1101?? 110i. Addition. 0.100gr.herylthiocy- .040 gr. benzylthioanate. cyanate. Tem erature 30C 39C 0.010 gr. benzyisul- Beac on time.. Addm 1L nde. Decrease oiweight 0.050 gr. Quimbin (a 1mpedingaction.. not made by V. Servo oi Delden, Holland) Emm le 11] Temperature 40C 40C.
• Example X Temperature 39C 39C. geaction timelgfii ilzgfllin 90min.
• Example V Acid E804... E801. Addition.-. 0.100gr. dithiocyanoethane. Temperature 78 C 78Q. Reaction time 90min..-. 90min. oiweight 77.5%--.” 0.650%. Impeding action .2%.
• Example VII Acid mam--- msot' 0.0125 gri benzylthiocyana e. Adam 0.050gr.dithiocyanoethane. Temperature 78C 78 Q. Reactiontime 90min 90mm. Decreeseoiweight 77.6% -- 0.240%. Impeding action 09.7%.
• the pickling bath of claim 1 in which the acid belongs to the group constituted by sulphuric and hydrochloric acids.
• the pickling bath of claim 1. in which the acid belongs to the group constituted by acetic, citric and oxalic acids.
• an aqueous solution containing a substance of the group constituted by non-oxidizing acids and acid salts, a substance of the group constituted by the aliqrlthiocyanates and the aralkylthiocyanates, with an addition of thiocarbanilide As a pickling bath, an aqueous solution containing a substance of the group constituted by non-oxidizing acids and acid salts, a substance of the group constituted by the aliqrlthiocyanates and the aralkylthiocyanates, with an addition of thiocarbanilide.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Combustion & Propulsion (AREA)
• Wood Science & Technology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geometry (AREA)
• General Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)

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Cited By (9)

• 0
  • NL NL83516D patent/NL83516C/xx active
  • NL NL47784D patent/NL47784C/xx active
• 1938
  • 1938-07-23 US US221009A patent/US2203649A/en not_active Expired - Lifetime
  • 1938-07-27 FR FR841279D patent/FR841279A/fr not_active Expired

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