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EP0543318A1 - Procédé et dispositif pour le nettoyage des parts métalliques - Google Patents

Procédé et dispositif pour le nettoyage des parts métalliques Download PDF

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Publication number
EP0543318A1
EP0543318A1 EP92119588A EP92119588A EP0543318A1 EP 0543318 A1 EP0543318 A1 EP 0543318A1 EP 92119588 A EP92119588 A EP 92119588A EP 92119588 A EP92119588 A EP 92119588A EP 0543318 A1 EP0543318 A1 EP 0543318A1
Authority
EP
European Patent Office
Prior art keywords
workpieces
wash tank
liquid
gas
cleaning
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP92119588A
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German (de)
English (en)
Inventor
Wilhelm Neubauer
Werner Comanns
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Aichelin GmbH Germany
Original Assignee
Aichelin GmbH Germany
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Aichelin GmbH Germany filed Critical Aichelin GmbH Germany
Publication of EP0543318A1 publication Critical patent/EP0543318A1/fr
Withdrawn legal-status Critical Current

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    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
    • B08B3/04—Cleaning involving contact with liquid
    • B08B3/10—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration
    • B08B3/102—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration with means for agitating the liquid

Definitions

  • the invention relates to a method for treating workpieces with a liquid, in particular for cleaning metallic workpieces for a heat treatment following cleaning, and a device for carrying out the method.
  • washing in particular for cleaning and / or rinsing metallic workpieces
  • This includes, for example, vacuum heat treatment, push-through, roller hearth, vertical retort or multi-purpose chamber furnace systems in which bright heat treatments,
  • Various annealing processes and hardening processes as well as diffusion processes such as nitriding, nitro carburizing, carbonitriding and carburizing can be carried out.
  • chlorinated hydrocarbons e.g. tetrachlorethylene (Per) or trichlorethylene (Tri) were used in the past to clean metallic workpieces. These were ideal cleaning agents, especially for removing greases and pigment dirt, the environmental impact of which but were only known and taken into account at a later date.
  • CHC chlorinated hydrocarbons
  • tetrachlorethylene and trichlorethylene especially tetrachlorethylene and trichlorethylene
  • Trichloroethene (tri) is now suspected of causing cancer, so that this cleaning agent has practically been withdrawn from circulation in Europe.
  • the types of contamination that occur on metallic workpieces are varied.
  • these contaminants can consist of cooling lubricants, greases, lapping pastes and pigments, or of hardening oils, dusts and metal chips.
  • substances such as nitrogen and / or carbon penetrate from the outside of the workpiece into the outer layers of the metallic workpiece via diffusion processes.
  • a clean surface is also essential for vacuum heat treatments, bright annealing processes, coatings or the like.
  • Such water-soluble cleaning agents for example highly wash-active, mostly surfactant-containing substances, have a reduced solubility for fats compared to chlorinated hydrocarbons (CHC), so that the cleaning process is supported by a relative movement and very highly concentrated solutions of these agents must be used and the cleaning process by a Relative movement between the workpiece to be cleaned and the cleaning liquid must be supported.
  • CHC chlorinated hydrocarbons
  • the relative movement between the workpiece and the cleaning liquid is achieved in that the workpieces are sprayed by means of swiveling arms, with a high exit velocity of the treatment liquid.
  • the workpieces are sprayed with the treatment liquid and the cleaning effect is a combination of a mechanical detachment of the dirt particles and a chemical action.
  • the emulsification of the fats and oils, caused by high discharge speeds, has a disadvantageous effect on the bath condition.
  • the metallic workpieces were removed from the bath or the spraying device and then dried by means of heated circulating air by evaporation with the aid of the inherent heat of the parts or by blowing off or by means of circulating air heating.
  • the cleaning agents used can only be used in a certain temperature range. If, for example, a cleaning bath has an excessively high temperature (close to 100 ° C), the cleaning agents are chemically changed and their cleaning effect deteriorates considerably. On the other hand, if the cleaning bath is not warm enough (below the cloud point or just above it), the cleaning effect also diminishes because the washing activities are no longer adequately thermally supported. The higher viscosity of the greasing complicates the chemical washing process.
  • this known device with the known method used has the disadvantage that in the important first phase of the cleaning process, namely when the tank is flooded, there is no sufficient cleaning effect, in particular with regard to coarse dirt, that contact of the wet workpieces occurs during the subsequent process steps with the outside atmosphere still lasts for a certain time and that finally the workpieces in certain areas (blind holes, cavities, scooping surfaces) are not sufficiently washed around by agitated bath.
  • a method for cleaning office machines and similar mechanical devices is known from DD-PS 91 177. Then the office machines mentioned should be cleaned in a bathroom, rise in the bubble columns, which are formed by a pulsating gas flow.
  • a cleaning device for hospital equipment is known in which cleaning fluid is moved by spraying and the like by means of compressed air.
  • a cleaning device for small machine parts in which the machine parts are introduced into a basket-like vessel, the bottom of which is formed by a grid. Below the grille is a tube ring, the top of which is provided with outlet openings for air bubbles.
  • the invention is therefore based on the object of developing a method and a device of the type mentioned in such a way that the above disadvantages are avoided and that the cleaning effect of metallic workpieces is improved overall.
  • the pressure-free gush pouring onto the workpieces with a very high flow rate also penetrates into inaccessible areas of the workpieces, forms vortices there and also takes dirt particles from there. This cannot be achieved with conventional devices in which thin liquid jets are directed onto the workpiece under high pressure, because there, on the one hand, only punctiform areas of the workpiece surface can be applied and, on the other hand, as already mentioned, inside areas are inaccessible.
  • the procedure according to the invention has the advantage that the workpieces are rinsed for a long time before the cleaning bath is let in, during a time in which injecting air would have no effect at all. because no immersion bath has been let in yet.
  • the subsequent process sequence has the advantage that the workpieces are kept constantly under liquid, even when the treatment bath is drained, with the result that no undesirable chemical reactions can form on the workpiece surface.
  • Another important advantage of the method according to the invention is that the treatment bath is continuously cleaned in parallel, during all the steps in which the treatment liquid is used, so that a completely self-sufficient system is created to which no further treatment liquids have to be added.
  • the method according to the invention is not restricted to certain sequences of washing or rinsing steps.
  • the method according to the invention can be used, for example, for washing with subsequent rinsing or for pre-washing, intermediate washing and post-washing with or without intermediate or subsequent rinsing steps.
  • the method according to the invention can also be used in conjunction with heat treatment processes, which is preferred, but it can equally well be used advantageously in other manufacturing processes.
  • a completely demineralized water is used as the rinsing liquid and this is mixed with a detergent after step i) and used as a cleaning liquid for a further subsequent process implementation.
  • This measure has the advantage that even a "used" rinsing bath can subsequently be used as a cleaning bath, with demineralized water being particularly suitable as a starting substance for a cleaning liquid.
  • a fine-pearled gas stream in particular with pearl sizes in the millimeter range, is used.
  • This measure has the advantage that a large number of gas pearls hit it per surface unit of a workpiece, so that on the one hand an intensive liquid movement is caused with a high dissolving effect and on the other hand a high mechanical cleaning effect is achieved both by the flowing liquid and by the impacting gas pearls.
  • the gas is introduced into the liquid in a pulsating manner with intermittently increased pressure.
  • This measure has the advantage that an increased mechanical cleaning effect is achieved by the intermittent injection of the gas.
  • the intermittent pressing also ensures, for example, that gas bubbles adhering to the surface of the metallic workpiece are neither torn off mechanically or by pressure fluctuations, so that cleaning liquid can occur in their place or other highly accelerated gas beads can hit the metal surface.
  • the gas is air.
  • This measure has the advantage that an economical gas that is available at all times can be used.
  • the gas is a protective gas which does not undergo any chemical reactions with the surface of the workpieces and / or does not support such chemical reactions.
  • This measure has the advantage that if metals or metal alloys are used which are sensitive to oxygen, for example, or in which oxygen in connection with water can cause microscopic corrosion, such as, for example, with some low-quality iron alloys, these materials can be cleaned without the cleaning process changes take place on the surface.
  • the liquid is water.
  • This measure has the advantage that an economical and environmentally friendly liquid is used as a solvent for the cleaning agent, which is completely harmless for the handling personnel.
  • a different rinsing liquid with or without additives or water with washing-active substances.
  • the cleaning agent is water, to which a gentle, fat-dissolving cleaning agent is added, which does not undergo chemical reactions with the surface of the workpieces and / or does not support such chemical reactions.
  • This measure has the advantage that no residues of the cleaning agent remain on the surface after washing processes.
  • the cleaning agent is neutral to slightly alkaline.
  • This measure has the advantage on the one hand that metals or metal alloys in these pH ranges of aqueous media are not attacked and that such media are environmentally neutral and harmless to the people who handle them.
  • the gas introduced has the temperature of the liquid.
  • This measure has the advantage that there is less solubility of the gas in the liquid in connection with the increased temperature control compared to normal temperature, so that even gases which tend to dissolve in a liquid under pressure do not do so under these circumstances but through the liquid as gas bubbles.
  • the workpieces are poured into a drum through which liquid can flow, the drum being immersed in the liquid and the gas beads flowing through the drum.
  • This measure has the advantage that a particularly intensive mixing and swirling of workpieces, liquid and gas flow is achieved by the additional movement of the bulk material in the drum. This makes it possible, for example, to clean even very small parts such as screws or the like with incised threads.
  • a particular advantage of the device according to the invention, as well as of the method according to the invention, is its flexibility by stringing together partially known and partially new plant components or process steps. This results in a particular degree of expandability and adaptability of the device or the method.
  • the gas injection device has a wall facing the liquid and provided with openings, through which the gas can be pressed into the liquid.
  • This measure which is known per se, has the advantage that the gas stream for agitating the bath is generated over a large surface and thus covers the entire interior of the wash tank.
  • the wall also extends laterally in the wash tank and the gas can be injected through the lateral openings under such a pressure that the gas flow reaches at least the center of the cross-sectional area of the wash tank in the lateral direction.
  • This measure has the advantage that, for example, if a round cylindrical container is used, the gas beads flow into the liquid not only from below but also from the side, in such a way that, viewed in the horizontal direction, they extend at least to the central longitudinal axis.
  • the lift then results in an increasing cam track. This means that even upper, possibly recessed surfaces can be cleaned excellently.
  • the gas injection device is designed as a double-walled body which can be accommodated in the container and whose side facing the liquid is provided with the openings.
  • This measure has the advantage that a simple and robust device is created, which can optionally also be retrofitted into existing wash tanks, so that, for example, containers that are still working with mechanical transport or agitators can currently be retrofitted.
  • the body is subdivided into segments and the segment sections can be supplied with the gas independently of one another.
  • This measure has the advantage that, depending on the type and length of the workpieces to be cleaned, differently designed gas streams can be generated.
  • the gas injection device is designed as a porous ceramic.
  • This measure has the advantage that no complicated hollow body has to be produced and that the gas bubbles distribute themselves by themselves.
  • a device 10 shown in FIG. 1 has a wash tank 12, a first tank 14 for a first treatment liquid, a second tank 16 for a second treatment liquid, a vacuum station 18, a filter device 20 and a device 22 for injecting a gas into the wash tank 12 on.
  • the wash tank 12 is circular in cross-section and closed at its top with a lid 26. Inside the Wash tanks 12 is a holding device 28 which is provided for receiving a batch of workpieces 30. The holding device 28 can be inserted into and removed from the wash tank 12 from above in the vertical direction with the lid 26 open.
  • the workpieces 30 are preferably metallic workpieces, i.e. Conventional machine parts, which are preferably to be subjected to a heat treatment, for example nitro carburizing, at a later point in time.
  • the workpieces 30 therefore have design-related cavities, bores and the like, which can be open upwards, downwards or to the side.
  • a drum 32 is held in the holding device 28, which is provided with a horizontal shaft 34.
  • the shaft 34 extends laterally through the wall of the wash tank 12 and is driven by a drive 36 outside the wash tank 12.
  • the drum 32 is used for receiving bulk material, not shown here.
  • the drum 32 is designed such that it is provided with openings on its circumference so that liquid and gas bubbles can pass through it while the bulk material contained in the drum 32 is retained.
  • the wash tank 12 is provided with an overflow 38 at its upper edge.
  • the overflow 38 is shown on the wash tank 12 as an overflow running around the outside.
  • a preferred embodiment of the invention is characterized in that the overflow runs on the inside of the wash tank 12. In this way, process sequences are moved into the interior of the wash tank 12, which is advantageous with regard to vacuum applications.
  • the overflow 38 is connected on the one hand via a line 40 to the second tank 16, which in the exemplary embodiment shown contains a cleaning liquid 42. Furthermore, the overflow is connected via a line 48 to the first tank 14, which contains a rinsing liquid 47 in the exemplary embodiment shown.
  • the lines 40 and 48 are provided with valves in order to be able to establish or block the connection between the overflow 38 and the tanks 14 and 16, as will be explained in detail below.
  • the second tank 16 containing the cleaning liquid 42 is connected via a line 41 to the suction side of a pump 43.
  • the pump 43 is connected on the output side via a line 44 to a pipe socket 46 which is arranged in the bottom of the wash tank 12.
  • Corresponding valves are also provided between tank 16 and pump 43 or pump 43 and pipe socket 46, as will be explained below.
  • the pump 43 is also connected on its suction side via a line 45 to the first tank 14 containing the rinsing liquid 47.
  • the tanks 14 and 16 are each provided with a heater 49 in the area of their bottom.
  • the tank 16 is provided with a laterally arranged pre-separator 50 which is connected to the actual interior of the tank 16 via an overflow.
  • the pre-separator 50 is also connected to the tank 16 via a line (not shown) and a pump, so that liquid can be pumped into the tank 16 by the pre-separator 50.
  • the tanks 14 and 16 are provided with an overflow weir, so that floating dirt of the liquids 42 and 47 get into the pre-separator 50.
  • a skimmer again runs in the pre-separator 50 in order to collect the dirt and then to be able to remove it.
  • the pre-separator 50 is also connected to the filter device 20, which in turn has a filter 55 and an oil separator 54.
  • the filter device 20 is not absolutely necessary, it can also be connected.
  • the filter 55 serves to separate solids from the liquid coming from the pre-separator 50.
  • the purpose of the oil separator 54 is to separate oily phases from this liquid, the separated oil phase being able to be removed via an oil extraction 57 and brought to a disposal point. Liquid leaving filter 55 can be returned to tank 16.
  • the vacuum station 18 has a vacuum pump 70 which is connected to the interior of the wash tank 12 via a line 71.
  • the line 71 preferably opens into the wash tank 12 just below the overflow 38.
  • the vacuum pump 70 On the pressure side of the vacuum pump 70, it is connected to a cold trap 72 and a collector 73. There is also a valve in line 71, as will be explained later.
  • the wash tank 12 can be closed in a vacuum-tight manner in the region of the cover 26 or the overflow 28.
  • the device 22 for injecting a gas into the wash tank 12 has a pressure container 60 in which a gas under pressure is stored.
  • the pressure vessel 60 can in turn be connected to a compressor (not shown in FIG. 1) be connected. It is also possible to use a blower at this point.
  • the gas processed in device 22 is preferably air, but a non-reactive protective gas can also be used. It is also possible to design the device 22 such that the gas is warmed up before it is fed to the wash tank 12.
  • the pressure vessel 60 is connected by means of a line 61, in which corresponding pressure control or pressure reducing valves are arranged, to a connecting piece 62 extending through the wall of the wash tank 12. From there, the line 61 leads to a plate-shaped hollow body 63, which is arranged in the region of the bottom of the interior of the wash tank 12.
  • the plate-shaped hollow body 63 the plate plane of which extends approximately horizontally, preferably fills the inner cross section of the wash tank 12 as completely as possible in the region of the floor. In any case, it is desirable that the dimensions of the hollow body 63, in vertical view, are approximately the same size as the dimensions of the holding device 28.
  • the plate-shaped hollow body 63 can be constructed from stainless steel sheets, the stainless steel sheet forming the upper plate surface being provided with openings 65.
  • the openings 65 consist of bores which have a diameter of approximately 1 mm and are arranged at a distance of preferably 25 mm from one another.
  • a porous ceramic can also be used, which encloses an air distributor pipe and through whose pores the air flows.
  • the device 10 shown in FIG. 1 also has an electronic control device 75, via the inputs 76 thereof Process parameters can be entered, while the outputs 77 control the units of the device 10, in particular the numerous valves and pumps.
  • the cover 26 of the wash tank 12 is opened (not shown) in order to move the holder 28 with the workpieces 30 into the wash tank 12 from above by means of a crane or the like.
  • the wash tank 12 is closed again by closing the lid 26.
  • the closure does not yet have to be vacuum-tight, but it should at least protect against splashing water.
  • the heater 49 in the second tank 16 is initially set with the cleaning liquid 42 in preparation for carrying out the method, and in parallel the heater 49 in the first tank 14 is also set with the rinsing liquid 47, provided that a rinsing process is desired.
  • the cleaning liquid 42 and optionally the rinsing liquid 47 are heated to a temperature between 50 ° C. and 90 ° C., preferably in the range between 80 ° C. and 90 ° C. This is a temperature at which detergents and detergents (if any are added) are at their optimal Work area because the agents mentioned chemically change at even higher temperatures and the cleaning or rinsing effect decreases at lower temperatures.
  • the control unit 75 opens the necessary valves.
  • a valve 41a is opened in line 41, which connects second tank 16 to the suction side of pump 43.
  • a valve 51a in the line 51 is opened, which connects the pressure side of the pump 43 to the surge shower 52.
  • a valve 67a in line 67 is opened, which connects line pipe 65, which acts as a drain, of wash tank 12 to second tank 16 via line 66.
  • a circuit of cleaning liquid 42 is established, which leads from the second tank 16 via the valve 41a, the line 41, the pump 43, the line 51, the valve 51a to the surge shower 52.
  • the delivery rate of the pump 43 and the flow cross-sections of the valves 41a and 51a are so dimensioned via the electronic control unit 75 that an unpressurized surge 80 of cleaning liquid 42 emerges from the surge shower 52, the flow rate of which is in the range between 100 m3 / h and 300 m3 / h per m2 surface of the workpieces 30 is set.
  • the surge 80 thus flushes the workpieces 30 without pressure and reaches the second tank 16 again via the pipe socket 65 which acts as a drain, the lines 66 and 67 and the opened valve 67a.
  • the workpieces 30 are pre-cleaned by the non-pressurized surge 80 because the surge 80 entrains and removes adhering dirt, in particular pigment dirt, but also greases.
  • the cleaning liquid 42 preferably consists of an aqueous solution of a non-foaming neutral cleaner with temporary corrosion protection.
  • a neutral cleaner has a relatively weak oil emulsifying effect, but is absolutely environmentally friendly and does not attack the goods to be cleaned, nor do people who handle this liquid are affected in any way.
  • the weakly alkaline temporary corrosion protection remains as a thin protective layer on the workpieces and can be completely evaporated at temperatures above 300 ° C without leaving any residue.
  • the method step explained above with reference to FIG. 2 is carried out for a period of preferably between one minute and 10 minutes.
  • control unit 75 switches to a next method step, which is illustrated in FIG. 3.
  • an immersion bath 83 is formed in the wash tank 12, the level 85 of which rises continuously, as indicated by an arrow 86.
  • the wash tank 12 thus fills continuously with a warm cleaning immersion bath 83 and this process step continues until a fill level indicator (not shown) detects that the liquid level 85 has reached the overflow 38. As soon as this is the case, the present method step is ended.
  • FIG. 4 shows the next process step in which the bath 83 is circulated and agitated.
  • connection between the second tank 16 and the surge shower 52 is initially maintained but, for example by reducing the delivery capacity of the pump 43, is reduced by, for example, 30% to 80%, so that the surge shower 52 only has a very great effect much smaller gush 80 'emerges.
  • the control unit 75 now opens a valve 40a in the line 40 between the overflow 38 and the second tank 16, so that the cleaning liquid 42 flowing over the overflow 38 can flow into the second tank 16.
  • valve 51a in the line 51 to the surge shower 52 can alternatively be closed and a connecting valve 51b can be opened, which connects the pressure side of the pump 53 to the bottom of the wash tank 12.
  • control unit 75 actuates the device 22 for injecting gas by opening a valve 61a in the line 61 between the pressure vessel 60 and the plate-shaped hollow body 63.
  • the gas or the air which emerge from the plate-shaped hollow body 63 are there under a pressure which is slightly above the ambient pressure prevailing there in the area of the openings 65.
  • the compressed air emerges from the plate-shaped hollow body 63 through the numerous openings 65 as small gas pearls, which then flow rapidly upwards to the overflow 38 due to the pressing pressure and their buoyancy.
  • the air bubbles flowing out of the openings 65 do not run through the numerous impingement points of the holding device 28 or the workpieces 30 contained therein in a straight line direction, but in a serpentine, partially swirled path.
  • the air bubbles also pass through the drum 32, so that the bulk material received there is also flowed around in a pearly manner when the drum 32 rotates.
  • the valve 61a can either be kept open continuously by the control device 75, the intensity of the agitation being able to be influenced by the air flow. Alternatively, however, it is also possible to alternately open and close the valve 61a in a predetermined manner, so that pulsating pressure surges are used. To this For example, the compressed air can be briefly pressed into the wash tank 10 at 5-10 bar at intervals of approximately 10-15 seconds.
  • non-foaming neutral cleaner ensures that no excessive foam is formed even when it is blown intensively into the wash tank 12.
  • the cleaning liquid 42 is at the working temperature, the workpieces 30 are degreased by means of the detergent substances in the detergent, for example anionic surfactants, i.e. cleaned of adhering lubricating oils and the like.
  • the amount of the circulated liquid which is supplied by the pump 43 in this process step can also be adjusted depending on the degree of contamination of the workpieces 30.
  • the delivery rate of the pump 43 can also be changed over the course of this method step, for example, by working first with a higher throughput and then with a lower throughput.
  • the method step explained above with reference to FIG. 4 is preferably carried out for a period between 3 minutes and 15 minutes.
  • control unit 75 switches to the next method step, which is explained with reference to FIG. 5.
  • control unit 75 switches the pump 43 back to a delivery rate that corresponds wholly or almost to the delivery rate of the method step explained with reference to FIG. 3.
  • a surge 80 now emerges from the surge shower 52, the flow rate of which is between 100 m3 / h and 300 m3 / h.
  • the valve 67a in the line 67 is opened again, so that the bath 83 runs out of the wash tank 12, as indicated by the arrow 86 'pointing downward on the liquid level 85 in FIG. 5.
  • the continuous pressure-free rinsing of the workpieces 30 in the process step illustrated in FIG. 5 has the following meaning: If, by draining the bath 83, the liquid level 85 drops, it can happen that dirt particles that float during emptying settle on the workpieces 30 when the liquid level 85 passes through these workpieces. However, this is prevented by the fact that abundant fresh, ie cleaned, cleaning liquid 42 is constantly supplied from above, namely from the surge shower 52, because the workpieces 30 are then continuously rinsed even when the bath 83 is drained.
  • the control unit 75 switches over to the next method step, which is shown in FIG. 6.
  • the cover 26 of the wash tank 12 must be closed in a pressure-tight manner.
  • the control unit 75 now opens a valve 71a in the line 71 between the interior of the wash tank 12 and the vacuum pump 70. At the same time, the vacuum pump 70 is switched on.
  • the workpieces 30 at this time have the temperature of the bath 83, i.e. are at a temperature of, for example, 80 ° C and 90 ° C.
  • the vacuum pump 70 now generates a vacuum in the interior of the wash tank 12. At about 800 mbar, the evaporation of the residual liquid starts on the workpieces 30 and the water vapor is, as indicated in FIG. 6 with arrows 90, via the line 71 sucked off.
  • the vacuum pump 70 now reduces the pressure in the wash tank 12 to 200-300 mbar, which corresponds to the steam pressure at a water temperature of 60 ° C - 80 ° C.
  • the liquid still on the workpieces 30 consequently evaporates, the evaporation process taking place more quickly on flat surfaces than in the region of bores, cabbages or so-called scooping surfaces, ie depressions of the workpieces 30 opening upwards.
  • the drying process is maintained for a period of between 3 minutes and 10 minutes. As soon as the last liquid has evaporated from the workpieces 30, the pressure in the interior of the wash tank 12 drops suddenly, for example to 70-80 mbar, because there is no longer any liquid to evaporate.
  • the drying process is ended by the control unit 75 by means of a suitable time control or, if appropriate, by a pressure sensor (not shown) which registers and reports this pressure drop.
  • a treatment step with a further treatment liquid can now follow or even before the drying process, for example rinsing the workpieces 30 with the rinsing liquid 47 contained in the first tank 14 same, so that in this respect reference can be made to the description of FIGS. 2-5.
  • the liquid in question for example the cleaning liquid 42
  • the filter device 20 During the entire duration of the method, in particular during the method steps in which the bath 83 is circulated, the liquid in question, for example the cleaning liquid 42, is continuously cleaned, as at the beginning of FIG. 1 has been explained in connection with the filter device 20.
  • the device 10 operates completely independently, i.e. no need to add or remove treatment fluids during operation.
  • demineralized water is used as the basis for the treatment liquids.
  • the fully demineralized water can initially be used as a rinsing liquid 47, because this prevents salt stains from forming on the workpieces after the rinsing during the drying process (FIG. 6), which interfere with the subsequent heat treatment, in particular with nitro carburizing.
  • the rinsing liquid 47 can be prepared by adding suitable cleaning agents even when it can no longer be used as a rinsing liquid and can be used as a cleaning liquid 42 for subsequent washing processes. In this way too, extreme use can be made of the liquids used without having to refill new liquids.
  • the line is expediently 71 'between the vacuum pump 70 and the wash tank 12 connected to the cover 26.
  • the vacuum pump 70 is switched on via the control device 75 and at the same time the valve 71a 'in the line 71' is opened.
  • the vacuum pump 70 Since the bath 83 is filled up to the overflow 38 in this process state, the vacuum pump 70 generates a strong negative pressure in the remaining small air space 91 in the area of the surge shower 52.
  • the negative pressure is now set so that the bath 83 begins to boil despite the temperature of 100 ° C. being below the boiling point of water at atmospheric pressure.
  • the vacuum must be set so that it corresponds to the saturation vapor pressure of water at the respective lower temperature and the hydrostatic pressure in the wash tank 12 is also taken into account, i.e. the height of the liquid column inside the tank.
  • the bath 83 begins to boil, even though its temperature is below 100 ° C.
  • the boiling of the bath 83 has the result that steam bubbles form at every point in the bath 83, that is to say not only on the surfaces of the workpieces 30, but rather also in cavities, bores, blind bores, scoops and the like.
  • the vapor bubbles thus also arise at those locations on the workpieces that cannot be reached by air bubbles that were generated by the device 22 for injecting gas.
  • the rising steam bubbles take along dirt particles via adhesive forces, with the result that blind bores, scooping surfaces and the like can also be cleaned by taking dirt particles with them.
  • the intensity of the boiling can be varied by adjusting the negative pressure accordingly via the vacuum pump 70.
  • the dirt carried up by the steam bubbles during the vacuum cooking collects on the surface of the bath and can be removed from the wash tank 12 in the manner already described via the overflow 38 after the cooking phase has ended.
  • the cooking of the bath 83 can be provided both during cleaning and during rinsing, because the chemical cleaning process is supported during cleaning, while the difficult to access spaces can be rinsed out in the manner mentioned during rinsing. It is understood that it is also possible to circulate and / or agitate the bath 83 when cooking under reduced pressure.
  • the suction side of the pump 43 is connected to the pipe socket 65 via a line 95, a valve 95a being arranged in the line 95.
  • the corresponding treatment liquid can now be sucked off the pipe socket 65 despite the negative pressure prevailing in the wash tank 12 and added again via the surge shower 52. It is understood that in this case as well, suitable measures can be used to continuously clean the respective treatment liquid (not shown).
  • a condenser 92 is arranged in the line 71 'because the vacuum pump 70 sucks off the vapor of the respective treatment liquid in the manner described and this vapor should not get into the vacuum pump 70. For this reason, an appropriate supply of air will ensure that the vacuum pump 70 always draws in a mixture of air and steam, the steam in the condenser 92 then precipitating out and being supplied to the respective tanks for the treatment liquids. This has the advantage that the treatment liquids do not thicken, i.e. Salt up by keeping the water loss as low as possible.
  • the amount of steam for the vacuum pump 70 is reduced by the amount of condensed steam, so that the vacuum pump 70 can be economically small.
  • the vacuum pump 70 can only pump out saturated air
  • the air required by the vacuum pump 70 is preferably supplied via the hollow body 63. You can measure the air required by the vacuum pump 70 so that it just corresponds to the amount of flotation air.
  • Vacuum cooking can now be integrated in a variety of ways into the process steps explained above with reference to FIGS. 2-6:
  • vacuum cooking can be used permanently in the immersion process, with the result that cooking is carried out under vacuum during the entire cleaning or rinsing time.
  • vacuum cooking in the immersion process can also be used for floating, i.e. each for part of the cleaning or rinsing time.
  • the vacuum cooking method can also be used in a pulsating manner by appropriate setting by means of the control device 75, be it during the entire cleaning or rinsing time or during individual time segments.
  • a pulsating vacuum boiling can be achieved in this case by strongly evacuating the wash tank 12 until the boiling effect sets in or almost sets in, in order to then bring to a boil by the sudden addition of fresh air, i.e. to cause a pressure release.
  • the fresh air can be supplied via the hollow body 63 or also via the surge shower 52.
  • the step of vacuum cooking can last from 1 min to 20 min.
  • FIG. 8 shows a variant of a device 100, only one wash tank 104 being shown here, which largely corresponds to the wash tank 12 of the device 10 according to FIGS. 1-7. Therefore, essentially only the deviating elements will be described below and in Fig. 8 the same reference numerals have been used for corresponding components.
  • the wash tank 104 is also designed as a container which is approximately circular in cross section and is provided on its bottom with a pipe socket 105, which is intended here to represent the pipe socket 46 and 65 of the wash tank 12 according to FIGS. 1-7.
  • the wash tank 100 also has a drum 106 which can be rotated about a horizontal axis 108 via a drive 107. Hexagonal workpieces 110, 110 ' « are contained in the drum 106.
  • the wash tank 104 is provided with an overflow 111, which is connected both to the second tank 16, which contains the cleaning liquid 42, and to the first tank 14, which contains the rinsing liquid 47.
  • the wash tank 104 is connected to the vacuum station 18 via a side connection.
  • a connection piece 114 can also be present in the cover 112.
  • the surge shower 113 is arranged on the inside of the cover 112 and, in the manner already explained several times, serves to flush the workpieces 110 accommodated in the interior of the wash tank 104 with a surge without pressure.
  • the wash tank 104 is filled with the cleaning liquid 42 up to the overflow 111.
  • the wash tank 104 there is a holder 118 which carries various other workpieces 120.
  • a device 122 for injecting gas (in the exemplary embodiment shown in FIG. 8, the gas is nitrogen) consists of a hollow body 126 which has a bottom part 130 and a side part 131.
  • the side part 131 extends on one side of the holder 118 and surrounds it at least over a large part of its circumference.
  • the hollow body 126 is again provided on the side facing the holder 118, as previously described, with numerous openings, which are designed as nozzles 128 in the embodiment shown in FIG. 8.
  • the nitrogen coming from the pressure vessel 60 emerges from the nozzles 128 in the form of fine beads or bubbles 127.
  • the bubbles 127 flow completely around the workpieces 120, as is indicated, for example, by an arrow 136.
  • Providing the side part 131 also produces a laterally directed bubble flow, as is indicated, for example, by the arrow 139. This creates an upwardly curved line because the bubbles emerging from the side nozzles 128 soon tend to rise due to the buoyancy.
  • the pressure that emerges from the side nozzles 128 gas bubbles 127 is adjusted during a cleaning process so that they reach at least approximately the longitudinal central axis of the wash tank 104, ie seen in the section of FIG. 8, as indicated by the arrow 138, at least via the half width in the lateral direction.
  • the side part 131 which at least partially surrounds the holder 118, ensures that rapid cleaning is possible even with workpieces 120 of complex shape.
  • the hollow body 126 can be subdivided into a top section 134, a middle section 135 and a bottom section via separating slides 132 and 133, so that, depending on the type of goods received in the wash tank 104, gas 141 only in the area of the bottom or also one or more one above the other arranged side areas is pressed.
  • the rising gas beads 127 also generate a secondary flow, as indicated by an arrow 137.
  • the liquid received in the wash tank 104 then flows in a circulating circuit.
  • FIGS. 9 and 10 show yet another exemplary embodiment of devices according to the invention, as can be used to carry out the method according to the invention.
  • a device for cleaning, in particular, metallic workpieces which comprises a wash tank 151.
  • a holder 152 for workpieces is in turn provided in the wash tank 151.
  • the arrangement is such that the holder 152 can be removed from the wash tank 151 in the horizontal direction via a loading door 153.
  • the loading door 153 is preferably displaceable in the vertical direction, as indicated by an arrow.
  • the liquids and gases can be supplied and discharged via lines 154, 155 and 156 in the manner already explained in detail, with no differences arising in the course of the method.
  • surge shower 157 which also delivers a pressure-free water surge in the device 150, even if the area of action is greater in the horizontal construction shown in FIGS. 9 and 10 than in the vertical arrangement in FIGS. 1-8.
  • the wash tank 151 is arranged on a frame 160 which at the same time holds the tanks 161, 162 for the treatment liquids.
  • the tanks 161, 162 are again provided for the cleaning liquid and the rinsing liquid.
  • an additional heater can be provided in the wash tank 12 in order to be able to work with cooler parts or to be able to dry even with large amounts of water remaining by the additional heater applying the required additional heat of vaporization.
  • Ultrasonic generators can also be provided in the wash tank 12 in a manner known per se, in order to cause cavitation in the treatment liquid by extreme physical forces. In this way it is possible to be able to remove inorganic substances which are difficult to adhere to the workpieces, as well as impurities which have worked into the surface of the workpieces.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Cleaning By Liquid Or Steam (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
  • Coating Apparatus (AREA)
EP92119588A 1991-11-22 1992-11-17 Procédé et dispositif pour le nettoyage des parts métalliques Withdrawn EP0543318A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4138432 1991-11-22
DE4138432A DE4138432C1 (fr) 1991-11-22 1991-11-22

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EP0543318A1 true EP0543318A1 (fr) 1993-05-26

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Country Status (9)

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US (1) US5268035A (fr)
EP (1) EP0543318A1 (fr)
JP (2) JPH0661968U (fr)
KR (1) KR930010231A (fr)
CN (1) CN1072738A (fr)
BR (1) BR9204611A (fr)
CZ (1) CZ344492A3 (fr)
DE (1) DE4138432C1 (fr)
HU (1) HUT62828A (fr)

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EP4467253A1 (fr) * 2023-05-24 2024-11-27 Elma Schmidbauer GmbH Dispositif de nettoyage avec une meilleure élimination des particules salees

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CN1894442B (zh) 2003-10-22 2012-01-04 内克斯系统公司 用于对工件进行流体处理的方法和设备
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DE102007016246B4 (de) * 2007-04-04 2019-02-21 Ecoclean Gmbh Verfahren zur Bereitstellung eines Reinigungsmediums und Verfahren und Reinigungsvorrichtung zur Reinigung eines Werkstücks
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KR101181584B1 (ko) * 2010-09-28 2012-09-10 순천향대학교 산학협력단 침적 슬러지의 물리화학적 세정방법
KR101589720B1 (ko) * 2014-05-21 2016-01-28 재단법인 한국화학융합시험연구원 강재류를 강 알칼리 전해수를 이용하여 세정하는 장치
JP2017140605A (ja) * 2016-02-12 2017-08-17 光洋機械産業株式会社 洗浄方法及びこの洗浄方法に用いられる洗浄装置
JP7124278B2 (ja) * 2017-09-08 2022-08-24 大同特殊鋼株式会社 金属切削屑の洗浄方法および洗浄装置
KR101988019B1 (ko) * 2018-03-28 2019-06-12 (주)에스에이테크 기계부품 세척 시스템 및 방법
JP7125600B2 (ja) * 2018-07-20 2022-08-25 株式会社不二越 洗浄システム
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CN110280440A (zh) * 2019-07-23 2019-09-27 通海云石工贸有限公司 钢结构扣接件生产涂料装置
CN112808680B (zh) * 2019-11-15 2022-11-01 清华大学 一种基于流化床的穿衣颗粒不合格品回收系统
CN113289968B (zh) * 2021-04-07 2022-04-12 岭东核电有限公司 乏燃料组件的处理设备及方法

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CN107971181A (zh) * 2017-11-16 2018-05-01 张英丽 增压式浸渍系统及其浸渍方法
EP4467253A1 (fr) * 2023-05-24 2024-11-27 Elma Schmidbauer GmbH Dispositif de nettoyage avec une meilleure élimination des particules salees

Also Published As

Publication number Publication date
JPH0661968U (ja) 1994-09-02
US5268035A (en) 1993-12-07
BR9204611A (pt) 1993-05-25
KR930010231A (ko) 1993-06-22
HU9203642D0 (en) 1993-03-01
DE4138432C1 (fr) 1993-02-18
HUT62828A (en) 1993-06-28
CZ344492A3 (en) 1993-09-15
JPH0623332A (ja) 1994-02-01
CN1072738A (zh) 1993-06-02

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