EP0205819B1 - System for the stainless drying of objects with surfaces wetted by a liquid - Google Patents

Description

The present invention relates to a method and a device for spot-free drying of objects with a smooth surface.

The drying in question here is the last stage of a cleaning process for objects whose surfaces have a high degree of purity at the end of the cleaning process. This high degree of purity is a surface quality such as is required for a coating or sputtering.

• - chlorierten oder insbesondere mit fluorierten Kohlenwasserstoffen oder
• - wäßrigen Lösungen, die aus Wasser und Detergentien bestehen.

In the cleaning processes currently used in the metalworking industry, optics, electronics, etc., cleaning takes place in the cleaning stage

• - chlorinated or in particular with fluorinated hydrocarbons or
• - aqueous solutions consisting of water and detergents.

Deionized water is generally used for rinsing.

Various methods are known for drying an object wetted by a cleaning and rinsing process.

If the object is cleaned using chlorinated or fluorinated hydrocarbons, the drying is also carried out using chlorinated or fluorinated hydrocarbons, the object drying completely after being left in steam from chlorinated or fluorinated hydrocarbon when it is pulled out.

If the object is cleaned using an aqueous solution of water and detergents, dewatering must take place before the actual drying. With this dewatering, the object is dewatered either with isopropanol, dewatering fluid or with solvents containing additives before drying. Drying is carried out using the drying processes known per se with chlorinated or fluorinated hydrocarbons. After pulling out of the steam zone at the end of the process, the item is completely dry.

• - Die Gegenstände müssen vor dem Trocknen durch Behandlung mit Isopropanol oder mit Lösemittelverbindungen (Isopropylalkohol oder Additive) entwässert werden.
• - Die Lösemittel z.B. fluorierte und chlorierte Kohlenwasserstoffe sind als nicht umweltfreundlich zu betrachten, teuer in der Herstellung, und bei der Anwendung ist z.T. ein Schutz des Personals erforderlich.
• - Die vorhandenen Lösemittel, insbesondere aus fluorierten und chlorierten Kohlenwasserstoffen, können nicht bei allen Materialien z.B. Kunststoffen, wie Polycarbonat, problemlos angewendet werden.
• - Die in der Oberflächenschicht vorhandene Lösemittelrückstände können dazu führen, daß bei einer nachfolgenden Beschichtung der Oberflächen Haftungsprobleme mit der aufzubringenden Schicht auftreten, daß die Qualität der aufgebrachten Schicht und deren Lebensdauer geringer sind und daß beim Beschichten unter Hochvakuum die Chloride und Fluoride ausdampfen und das Vakuum verunreinigen.
• - Die Lösemittelrückstände können auch bei der Anwendung der Gegenstände deren Funktion beeinträchtigen, z.B. bei einem Ringlasergyro kann dadurch das eingefüllte gasförmige Medium verunreinigt werden, und somit die Funktion des Gyros beeinträchtigen bzw. verunmöglichen.

Although useful results are achieved with this drying process, they have the following disadvantages:

• - Before drying, the objects must be dewatered by treatment with isopropanol or with solvent compounds (isopropyl alcohol or additives).
• - Solvents such as fluorinated and chlorinated hydrocarbons are not considered to be environmentally friendly, are expensive to manufacture, and some protection of personnel is required during use.
• - The solvents available, especially those made from fluorinated and chlorinated hydrocarbons, cannot be used without problems with all materials, such as plastics such as polycarbonate.
• - The solvent residues present in the surface layer can lead to adhesion problems with the layer to be applied when the surfaces are subsequently coated, that the quality of the applied layer and its service life are lower and that the chlorides and fluorides evaporate and the vacuum when coating under high vacuum contaminate.
• - The solvent residues can also impair their function when the objects are used, for example in the case of a ring laser gyro the gaseous medium filled can be contaminated and thus impair or make the function of the gyro impossible.

In semiconductor technology, other drying processes that are specifically designed for these products and their manufacture are known. In the book "Semiconductor Technology", Volume 1 "Mechanical and chemical crystal processing, layer production", 1981, VEB VERLAG TECHNIK evaporation, displacement and thinning are mentioned for the drying of substrate surfaces, which are mostly used in combination.

The drying based on evaporation, i.e. by means of an infrared oven or with a heated medium, cannot be applied to an object with surfaces that need to be cleaned to a high degree because the remaining dry stains and residual dirt on the surface cannot be excluded, or is the rule. The reasons for this are the contaminated ambient air, the qualitatively inadequate degree of purity of the aqueous treatment medium and the drying medium, and the long treatment time required for the drying process.

If the ambient air is treated, the degree of purity is improved accordingly.

In the case of drying based on displacement, the substrate surface is blown on. This blowing can take place, for example, with purified nitrogen or purified air. In order to dry silicon wafers, eg solar cells, a drying process is used that combines displacement and evaporation. Here, the silicon wafers are cleaned in a solvent made of water, hydrogen peroxide and ammonium hydroxide solution, which is subjected to sound energy in the megahertz range, then rinsed with deionized water and finally in a spatially separated, separate drying station in a first phase with filtered room air for one minute is blown at a high flow rate exclusively from above in order to blow off most of the wetted water and then in a second phase for two to three minutes with a filtered room air heated to 100 _° C to completely dry the silicon wafers.

The procedure explained above represents a special case in semiconductor production for a number of flat, identical silicon wafers and is therefore not applicable everywhere, which is a disadvantage.

In the case of drying based on dilution, the water film thickness is reduced by centrifugation. The centrifugal effect removes the water from the surfaces of the object to be dried.

This method, also known as dry spin, has the disadvantage that only flat and disc-shaped objects, e.g. Semiconductor substrates can be dried perfectly.

• - es kann jeweils nur ein Substrat getrocknet werden,
• - es können nur plane und scheibenförmige Substrate getrocknet werden,
• - die Trocknung im wesentlichen auf die Zentrifugalwirkung beruht, so daß eine sehr hohe Drehzahl benötigt wird,
• - das Trocknungsgas rechtwinklig zur Substratoberfläche zugeführt wird und folglich nur eine untergeordnete Rolle beim Verdrängen spielt,
• - daß Gegenstände mit anderen Formen z.B. konvexe und konkave und/oder mit Löchern usw. nicht getrocknet werden können.

EP-A 0 137 947 discloses a drying centrifuge in which the substrate to be dried is fed through a number of stages to a drying stage by means of water nozzles, without the substrate coming into contact with the ambient air. After the water has been drained from the drying stage, the turntable with the substrate inside the chamber is raised, a drying gas, e.g. dry, dust-free nitrogen, is applied to the substrate surface, and the turntable is then rotated at approx. 5000 min- ¹ . Here, the water layer on the substrate surface is diluted by the centrifugal effect and the water on the substrate surface is displaced by the drying gas. This drying essentially has the following disadvantages:

• - only one substrate can be dried at a time,
• - only flat and disc-shaped substrates can be dried,
• the drying is essentially based on the centrifugal effect, so that a very high speed is required,
• the drying gas is supplied at right angles to the substrate surface and consequently only plays a subordinate role in the displacement,
• - That objects with other shapes such as convex and concave and / or with holes etc. cannot be dried.

The invention has for its object to provide a method for spot-free drying of objects in which, while avoiding the disadvantages mentioned, the object to be dried is kept in a defined purity by rapid and direct transition from a liquid to a gaseous treatment medium and by displacement the liquid treatment medium is dried by blowing with the gaseous treatment medium.

This object is achieved by the features of claim 1.

A device for spot-free drying of objects is characterized according to the invention by the features of claim 11.

• - zum Trocknen von mit wäßrigen Lösungen gereinigten Gegenständen der vorgängig erforderliche Entwässerungsvorgang entfallen kann,
• - keine Lösemittel verwendet werden, die eine chemische Reaktion mit dem Material des zu trocknenden Gegenstandes eingehen können,
• - ein qualitativ höherer Reinheitsgrad der Oberflächen erzielt werden kann,
• - auch sehr komplizierte geometrische Formen mit Sacklöchern, Durchgängen, Schrägflächen, konvexe und konkave Flächen problemlos getrocknet werden können,
• - das Verfahren umweltfreundlich ist und keine atmosphärische Verschmutzung zur Folge hat,
• - der Kostenaufwand für die Trocknung gegenüber den bekannten Verfahren wesentlich herabgesetzt wird,
• - der Zeitaufwand für die Trocknung gleich/kleiner 2 Minuten ist,
• - auch für Materialien wie Glas, Keramik, Germanium, Metall usw. geeignet ist,
• - der zu trocknende Gegenstand nicht aus dem letzten Spülbad in eine spezielle Trocknungseinheit transportiert werden muß,
• - daß Kunststoffe in Raumtemperatur getrocknet werden können, die empfindlich sind gegen Erwärmung,
• - zerbrechliche oder empfindliche Teile werden nicht beschädigt, und
• - die Temperatur des gasförmigen Behandlungsmediums im Bereich der Umgebungstemperaturen liegt.

The advantages that can be achieved with this invention are essentially that

• the previously required dewatering process can be omitted for drying objects cleaned with aqueous solutions,
• - no solvents are used that can chemically react with the material of the object to be dried,
• - a higher quality of the surface can be achieved,
• - even very complicated geometric shapes with blind holes, passages, sloping surfaces, convex and concave surfaces can be dried without any problems,
• - the process is environmentally friendly and does not result in atmospheric pollution,
• the cost of drying is significantly reduced compared to the known methods,
• - the time required for drying is equal to / less than 2 minutes,
• - is also suitable for materials such as glass, ceramics, germanium, metal etc.,
• the object to be dried does not have to be transported from the last rinsing bath to a special drying unit,
• - that plastics that are sensitive to heating can be dried at room temperature,
• - fragile or delicate parts are not damaged, and
• - The temperature of the gaseous treatment medium is in the range of the ambient temperatures.

In one embodiment of the method according to the invention, pure nitrogen, ultra-pure nitrogen, noble gas, pure air or ultra-pure air is used as the gaseous treatment medium. This has the advantage that contamination of the object during the drying process can be completely ruled out.

It is advantageous if the object is blown at a pressure in the range of 1-8 bar.

The bath level can be done by draining the treatment liquid or by moving the container containing the treatment liquid. This can prevent splashes from treatment liquid being generated by the onset of the blowing. It is advantageous if the bathing level is lowered within a period of approx. 0.1-5 seconds.

Because the object is blown in a targeted manner from a direction which can be changed with respect to the object and from a further direction which is fixed with respect to the object, objects of a similar, but not the same, geometric configuration, such as e.g. Eyeglass lenses from prescription production can be dried quickly because the liquid forced to the edge by the blowing in one direction is blown off the edge by the blowing in the other direction.

In one embodiment of the device according to the invention, the blowing device has a first blowing element, which is fixed with respect to the objects to be dried, and a second blowing element, which can be moved back and forth with respect to the objects to be dried, in order to selectively blow the objects to be dried from two directions, being the rays from the first and the second blowing element intersect at a certain angle. With this arrangement, the effect achievable by the blowing from a fixed direction and the blowing over the objects are improved and objects with a very complicated geometric shape are blown in full.

The first and second blowing elements can be arranged so as to be movable or offset in time with respect to the object to be dried, so that the jets from the blowing elements sweep over the objects in order to selectively blow the objects from two directions. This drying from two directions advantageously reduces the drying time.

In one embodiment of the device according to the invention, the blowing member is an elongated hollow body, the outlet opening or outlet openings extending over most of the length of the hollow body. This configuration advantageously allows a plurality of objects arranged side by side to be dried simultaneously.

In another embodiment of the device according to the invention, the bath has a container which is arranged in a tub, the upper part of the container consists of two members which are pivotably arranged on the lower part in order to close the container and the third device is with the lower part of the container connected to move the container up and down, the trough being provided with stops which are each movable in engagement with the organs in order to open the container during the upward movement and to close it during the downward movement.

This configuration allows items to be dried in batches, the treatment liquid being able to be used for a number of drying processes.

In another preferred embodiment of the device according to the invention, the device for moving the objects to be dried has a driving means which is mounted on the holding device, a driven means on which the objects to be dried are arranged and which is movably mounted in the holding device, and a transmission means connecting the driving means and the driven means. This advantageously allows objects of any geometric shape to be dried perfectly in a very short time.

The invention is explained below with reference to the accompanying drawings.

• Fig. 1 ein Ausführungsbeispiel einer Vorrichtung zum fleckenfreien Trocknen von Gegenständen,
• Fig. 2 eine schematische Darstellung der in Fig. 1 gezeigten Anblaseinrichtung, aus der die Zuordnung der Anblasdüsen zu den zu trocknenden Gegenständen ersichtlich ist,
• Fig.. 3 eine schematische Darstellung eines anderen Ausführungsbeispiels einer Anblasvorrichtung, aus der die Zuordnung der Anblasdüsen zu den zu trocknenden Gegenständen ersichtlich ist,
• Fig. 4a und 4b Querschnitte der Düsen,
• Fig. 5 ein weiteres Ausführungsbeispiel der Vorrichtung zum fleckenfreien Trocknen von Gegenständen, und
• Fig. 6 einen Schnitt entlang der Linie VI-VI in Fig. 5,
• Fig. 7 und 8 eine schematische Darstellung eines anderen Ausführungsbeispiels der Vorrichtung zum fleckenfreien Trocknen von Gegenständen in zwei Arbeitzuständen, und
• Fig. 9 einen Schnitt entlang der Linie VIII-VIII in Fig. 7, die einen Teil der Vorrichtung und des Behälters zeigt.

Show it:

• 1 shows an embodiment of a device for spot-free drying of objects,
• 2 shows a schematic representation of the blowing device shown in FIG. 1, from which the assignment of the blowing nozzles to the objects to be dried can be seen,
• 3 shows a schematic illustration of another exemplary embodiment of a blowing device, from which the assignment of the blowing nozzles to the objects to be dried can be seen,
• 4a and 4b cross sections of the nozzles,
• Fig. 5 shows another embodiment of the device for spot-free drying of objects, and
• 6 shows a section along the line VI-VI in FIG. 5,
• 7 and 8 are a schematic representation of another embodiment of the device for spot-free drying of objects in two working states, and
• Fig. 9 is a section along the line VIII-VIII in Fig. 7, showing a part of the device and the container.

The devices shown in FIGS. 1 and 2 essentially serve to dry flat objects, in particular spectacle lenses, and differ in the design of the blowing device.

As shown in FIG. 1, the device contains a container 1 with an upper part 2 and a lower part 3, which have an essentially circular cross section and different inside diameters. The container 1 is mounted upright on a frame 4. The container 1 is open at the top and closed at the bottom by a shut-off device 5. An overflow opening 6 is provided on the upper section of the lower part 3 in order to keep the liquid level of a treatment liquid filled into the lower part at a constant level. In the lower part 3 of the container 1 there is also a nozzle 7 for filling the treatment liquid, which opens into the lower part 3 at a level below the liquid level.

The treatment liquid is located in a storage container 8, which is connected to the nozzle 7 via a pipeline 9. A shut-off valve 10 is installed in this pipeline 9. To maintain the bath of treatment liquid there is a collecting container 11 which is connected via a pipe 12 to the outlet of the container 1 and via a pipe 13 to an overflow channel 14 on the lower part 3 of the container 1 in order to take up the treatment liquid from the lower part 3 of the container, and which is connected via a pipeline 15, in which a feed pump 16 and a shut-off valve 17 are installed, to the lower container part in order to convey the treatment liquid into the lower container part 3, the pipeline opening into the pipeline 9 before the nozzle 7.

As shown in FIG. 1, the lower container part 1 is formed from the cylindrical section 20 and a conical section 21, which tapers towards the outlet opening 22 of the container 1 and determines the outlet opening 22. The section 21 is designed such that the cross-sectional area of the outlet opening 22 is substantially equal to the cross-sectional area of the section 20. It is pointed out that the lower container part '3 can also consist of a single cylindrical section.

The shut-off device 5 already mentioned is a conventional gate valve 23 which is mounted on the one hand on a flange 24 on the lower part 3 and on the other hand on a flange 25 of the pipeline 12. The gate valve 23 is provided with a drive member 26.

In order to generate an atmosphere above the liquid level, which consists of a gaseous treatment medium, a nozzle 27 is provided. This nozzle 27 is movably arranged on a holding device 28 such that the height of the nozzle can be adjusted with respect to the liquid level. The holding device 28 is fastened to the inside of the upper container part 2 by means of holders 29.

A carriage 30 is mounted on the frame 4 and can be moved in the directions indicated by the arrow A. A frame 31 is mounted on the carriage 30 in a self-supporting manner so that it lies above the opening of the container 1.

A holding device 32 for the objects to be dried is attached or fastened to the frame.

The design of the holding device depends on the geometric shape of the object to be dried and is intended for spectacle lenses in the present case.

As can be seen from FIGS. 1 and 2, the holding device 32 contains two rods 33 which can be attached to the frame 31 at one end and two plates 34 which are fastened to the other ends of the rods 33. The plates 34 are U-shaped. In the area of the ends of the legs, two struts 35 are fastened parallel to one another, which serve as a support for the lenses 36 to be dried and keep the two plates 34 at a distance. The holder of the lenses 36 can be designed in accordance with that described in US Pat. No. 4,432,380.

The device is also provided with a device for blowing on the objects to be dried. An embodiment of such a device is shown in Figures 1 and 2. This device contains two fixed blowing elements 40, 41, which are mounted parallel to each other in the upper container part 2, so that they are always above the liquid level and two movable blowing elements 42, 43, which are at a certain distance above the fixed blowing elements 40, 41 in the upper container part - And are arranged movable. The movable blowing elements 42, 43 are each mounted on two identically designed holding devices, which have a guide 44 mounted on the frame 4, a push rod 45 arranged displaceably in the guide 44, a drive device with two wheels 46, 47 and has a support rod 48 which is attached to the push rod at one end and has a holder 49 at the other end for attaching the movable blowing element 42, 43.

The blowing device further comprises a storage container 50 for the gaseous treatment medium. This storage container 50 is via a line 51 in which a valve 52 is installed, with the nozzle 27, via a line 52 in which a valve 53 is installed, with the fixed blowing elements 40, 41 and via a line 54 into which a Valve 55 is installed, connected to the movable blowing members 42, 43.

Instead of the fixed blowing members 40, 41, a blowing member can also be used which has two outlet openings which are essentially arranged opposite one another. The blower is attached at both ends to a feed rod which is led out of the upper part 2 of the container. These push rods are connected to a drive to move the blowing member in the upper container part 2 into a rest position or working position.

FIG. 3 shows a further exemplary embodiment of the device for blowing on the objects, which is mounted in a housing which corresponds in its basic structure to the housing 1 shown in FIG. 1.

As Figure 3 shows, a bearing block 51 is attached to the inside of the upper container part 2. An upper holding device 52 and a lower holding device 53 are pivotably arranged on this bearing block 51, which are pivoted individually or together by a drive device 54. The drive device 54 is fastened to the bearing block 51 or upper housing part 2 by suitable means. The upper holding device 52 contains a one-armed lever 55 which is articulated at one end on the bearing block 51. At the other end of the one-armed lever 55, two holding members 56 are pivotally attached. The holding members 56 are designed in the present case as a one-armed lever and articulated at one end to the one-armed lever 55. A blowing member 57 is attached to the other end of the holding member 56. This blowing element 57 is an elongated hollow body which has a plurality of holes formed in a line or a slot which extends over most of its length. The holes and the slot form the outlet openings for the gaseous treatment medium. The other holding device 53 consists of a one-armed lever 58 which is articulated at one end on the bearing block 51. At the other end of the one-armed lever 58, a blowing member 59 is attached. Compared to the blowing member 57 on the upper holding device 52, the blowing member 59 on the lower holding device 53 is designed as a two-jet nozzle, in which the outlet openings are formed on the opposite sides of the hollow body.

Figures 4a and 4b show two versions of such blowing elements in cross section.

The method for drying spectacle lenses is explained below with reference to FIGS. 1-3.

Treatment liquid is poured from the storage container 8 through the pipeline 9 and the valve 10 into the lower container part 3 until the liquid level determined by the overflow opening 6 is reached. This liquid level is maintained by the system of overflow tank 11 and pump 16 if necessary. After the bath of treatment liquid is provided, the spectacle lenses 36 inserted in two rows and side by side in the holding device are inserted into the device from the device 30, 31 from above Container 1 retracted until the lenses 36 are completely immersed in the treatment liquid bath. A gaseous treatment medium is then introduced from the storage container 50 through the nozzle 27 into the space above the liquid level. The air present in the space above the liquid level is displaced by the gaseous treatment medium flowing out of the nozzle 27 and an atmosphere consisting of gaseous treatment medium is thus generated. This creates the conditions for the spot-free drying of the spectacle lenses 36, because in the container 1 there is now a bath of technically pure treatment liquid and above it an atmosphere of technically pure gaseous treatment medium. As a result, the treatment liquid is drained by opening the gate valve 5. This draining takes place very quickly because the outlet opening 22 of the lower container part 3 has a cross section which is substantially equal to the cross section of the lower container part. During this draining, the space released in the lower part 3 of the container by the sinking liquid level is filled by the gaseous treatment medium. By means of the device 30, 31, the spectacle lenses 36 are raised into a blowing position shown in dashed lines in FIG. 1. This blowing position is shown in FIG. In this position of the spectacle lenses 36, the blowing members 42, 43 are displaced relative to one another, as a result of which the spectacle lenses are blown from above by the downward jet of gaseous treatment medium. As a result of this blowing, which takes place at a specific flow rate, the treatment liquid adhering to the surface of the spectacle lenses 36 is displaced downward and the surface regions freed from treatment liquid are dried at the same time. The treatment liquid displaced downward by the blowing through the blowing members 42, 43 collects in the lower edge region of the spectacle lenses 36. The treatment liquid accumulated in the edge region of the spectacle glasses 36 is displaced by the two blowing members 40, 41 and by short, intermittent blowing at high pressure blown off outside. With this measure, the drying time is significantly reduced. Once the spectacle lenses 36 have dried in the above manner, the blowing members 42, 43 are shifted into the rest position and the holding device with the spectacle lenses 36 is moved out of the container 1.

A new drying cycle can then be carried out.

In the exemplary embodiment shown in FIG. 3, the method runs in the same way, in which case the movable blowing elements 57 are pivoted and not shifted.

Figures 5 and 6 show another embodiment of the inventive device for drying objects with a complicated geometric shape.

The device has a container 60 with a cylindrical upper part 61, a trough-shaped section 62 with a semicircular cross section which is butt welded to the upper part 61 with one leg 62a, and a conical lower part 63 which is welded to the outside of the other leg 62b and tapers towards the outlet. The container 60 is open at the top and closed at the bottom by a shut-off device 64. The inner legs 62b form an overflow edge 65, so that the level of the liquid level of a treatment liquid filled into the lower part 63 is determined. In the lower part 63 of the container 60, a nozzle 66 is provided for filling the treatment liquid, which opens into the lower part 63 at a level below the liquid level.

The treatment liquid is located in a storage container 67, which is connected to the nozzle 66 via a pipe 68. A valve 69 is installed in this pipeline 68. The trough-shaped section 62 serves as a collecting container and has two outlets 70. The outlet of the container 60 is connected to a feed pump 72 via a pipeline 71. The outlets 70 of the section 62 are each connected to the pipeline 71 via a pipeline 73, 74. The feed pump 72 is connected to the pipeline 68 via a pipeline 75 in which a shut-off valve 76 is installed. This creates a system for maintaining the liquid level, wherein the losses of treatment liquid from the storage container 67 can be covered if necessary.

The outlet opening of the container 60 is determined by the lower part 63 tapering towards the outlet. The lower part 63 is designed such that the cross-sectional area of the outlet opening is substantially equal to the cross-sectional area of the section with the smallest inside diameter of the lower part 63.

The shut-off device 64 already mentioned is a conventional gate valve 74 which is mounted on the one hand on a flange 78 on the lower part 63 and on the other hand on a flange 79 of the pipeline 71. The gate valve 74 is provided with a drive member 80.

The device also has a frame 81 on which a carriage 82 is mounted, which can be moved in the direction indicated by the arrow A. A frame 83 is mounted on the carriage 82 in a self-supporting manner so that it lies over the opening of the container 60. A holding device 84 for the object to be dried is detachably attached to the frame.

As already mentioned, the design of the holding device depends on the geometric shape of the object to be dried and is intended for a ring laser gyro in the present case.

As FIGS. 5 and 6 show, the holding device 84 contains a first strut 85, which is detachably fastened to the frame 83 at one end and has a bushing 86 at the other end, and a second strut 87, which is likewise attached to the frame 83 at one end is releasably attached and has a fork-shaped section 88 at the other end. To keep the two struts 85, 87 at a distance and to support each other, a rod 89 can be provided. In the fork-shaped section 88 and the sleeve 86, a shaft 90 is rotatably mounted, on which, for example, a ring laser gyro 91 is arranged in a certain position in a stable position. A bevel gear 92 is arranged on the shaft 90 and lies within the fork opening. This gear 92 is driven by a shaft 93. The shaft 93 is driven by another bevel gear 94a, which is drive-connected to a drive device 94, which is fastened to the strut 87. This drive device 94 can be an electric motor, for example.

As FIG. 6 shows, the device also contains a device for blowing the object with a gaseous treatment medium. This device comprises six nozzles 95, which are arranged in two rows of three nozzles opposite each other in the container upper part 61 in such a way that the outlet openings of two nozzles 95 lie on the same line. The nozzles 95 are adjustably mounted on holding devices 96 in order to be able to adjust their position with respect to the liquid level. The holding devices 96 are fastened to the inside of the upper container part 61 by means of brackets 97. In each case two opposing nozzles 95 are connected in parallel via a pipeline 98 to a storage container 99 for the gaseous treatment medium. A valve 100 is installed in each of these pipelines 98.

Instead of the individual nozzles 95 in each row, the blow-off elements shown in FIGS. to target adjacent objects.

The method for drying a ring laser gyro is described below with reference to FIGS. 5 and 6.

Treatment liquid is filled from the storage container 67 through the pipeline 68 and the valve 69 into the lower container part 63 until the liquid level determined by the overflow edge 65 is reached. This level of liquid is maintained by the gutter 62 and pump 72 system if necessary. After the bath of treatment liquid is prepared, the ring laser gyro 91 arranged in the holding device is inserted into the container 60 from above by the device 82, 83 until the ring laser gyro 91 is completely immersed in the bath of treatment liquid. In contrast to the method for drying spectacle lenses, a gaseous treatment medium is then introduced from the storage container through the lowermost nozzles 95 into the space above the liquid level. As with the method for drying spectacle lenses, this creates an atmosphere consisting of the gaseous treatment medium in order to create the preconditions for spotless drying of the ring laser gyro. The treatment liquid is then drained by opening the gate valve 77. This draining takes place very quickly because the outlet opening of the lower container part has a cross section which is essentially equal to the cross section of the lower container part 63. This draining of the treatment liquid can be accelerated by the treatment liquid being sucked off by means of the feed pump 72. The space released by draining the treatment liquid above the liquid level is filled by the gaseous treatment medium which flows in through the lowermost nozzles 95. The device 82, 83 raises the holding device and thus the ring laser gyro 92 into a blowing position shown in dashed lines in FIG. 6.

In this position, the ring laser gyro is blown on both sides by two nozzles 95 with gaseous treatment medium at a high flow rate. During the blowing, the ring laser gyro 91 is rotated by the device 92, 93.95 in order to blow off or blow off the liquid adhering to the surfaces and located in blind holes and to dry the ring laser gyro.

With this method, however, it is also possible to continuously move the ring laser gyro 91 upward and simultaneously rotate it to dry the object.

Another exemplary embodiment of the device for spot-free drying of objects is shown in FIGS.

The device contains a container 101 which is arranged so that it can be moved up and down within a tub 100. The tub 101 is mounted in a frame, not shown, so that it is accessible from above.

The container 101 consists essentially of a lower part 102 with a curved bottom and two flat side walls and two lid segments 103, 104 with a curved ceiling and two flat side walls, which are pivotably mounted at 105 on the side walls of the lower part 102.

A holding and connecting block 106 is fastened to a side wall of the lower part 102 (FIG. 9). The outlet opening 197 of the container 101 is led out via this connection block 106. In addition to the outlet opening, an inlet opening 108 and an opening 109 are also provided for the overflow.

As shown in FIG. 1, the outlet opening, inlet opening and overflow opening can be connected to a storage container and collecting container in order to supply the container 101 with treatment liquid.

As can also be seen from FIG. 9, the container 101 is connected to a device 110 via the connection block 106 in order to move the container 101 up and down within the tub 100. Such devices are known. In the present exemplary embodiment, the container 101 is moved up and down by a carriage 112 which can be displaced by means of a drive worm 111 and which is guided on two guides 113. The carriage 111 and the connection block 106 are connected to one another by a fastening bracket 114. Since the device 110 is arranged outside the tub 100, the corresponding side wall of the tub 100 has a recess 115.

The tub 100 encloses one for the through management of the process required treatment room, which is essentially filled by the gaseous treatment medium. The tub 100 is provided with a fan 116 which is arranged in a compartment 117 which is shielded from the treatment room. The fan 116 is connected to the treatment room via an inlet opening 118 and to the room surrounding the device via an outlet opening 119. In order to generate a uniform flow within the treatment room, a baffle 120 is provided on the side of the tub opposite compartment 117. The compartment 117 and the guide plate 120 are designed and arranged in such a way that there is essentially the same distance between them and the container.

The device also has a holding device 121 for the objects 122 to be dried. Since the design of the holding device 121 depends on the design of the object to be dried, an exemplary embodiment for holding eyeglass lenses 122 is shown schematically in FIGS. 7 and 8. Thereafter, this holding device 121 consists of two plates 123 which are connected opposite one another by struts 124, the struts 124 simultaneously serving as support members for the spectacle lenses 122. Rods 125 are welded to the plates 123 at one end. At the other end, the rods 125 are designed such that they can be suspended in a device (not shown) for moving the holding device 121 up and down. The device can be similar to the embodiment shown in FIG.

In order to create an atmosphere within the tub 100 and above the bath level, which consists of a gaseous treatment medium, two nozzles 130 are provided. These nozzles 130 are arranged in the area of the tub floor.

The device also includes a blowing device 132, which is divided into two functional units. As can be seen from FIG. 8, one functional unit contains two blowing elements 133, 134 and the other functional unit contains a number of nozzles 135 and 136 arranged one behind the other in each row with an adjustable nozzle head 137, 138, so that the direction of the emerging jet with respect to the object to be dried is adjustable. These functional units also differ in their function in that the blowing members 133, 134 can be moved back and forth as well as up and down and the nozzles 135, 136 can only be moved up and down. In order to move the blowing elements and nozzles 133 to 136, the blowing device contains means, not shown, which e.g. can be configured as follows: A support is arranged on a spindle arranged next to the tub 100. The blowing elements 133, 134 are mounted on a right and left hand winch spindle, which is mounted on the support and is driven by a motor. The nozzles 135, 136 are mounted on a spindle with a right-hand thread, which is also mounted on the support and is driven by another motor.

The blowing device 132, similar to that shown in FIG. 1, comprises a storage container for the gaseous treatment medium, which is connected to the blowing members 132, 134 and to the nozzles 135, 136 as well as to the nozzles 130 arranged inside the tub 100.

The method for drying spectacle lenses in the device shown in FIGS. 7-9 is described below.

The container 101 is filled with treatment liquid up to the line 140, which represents the bath level. This filling is monitored, e.g. with a level control loop. The filling can take place when the container 101 occupies the upper position in the tub 100. After the bath is provided, the spectacle lenses 122 inserted in the holding device 121 in two rows and side by side are inserted into the container 101 from above until the spectacle lenses 122 are completely immersed in the treatment liquid. In order to displace the air present above the bath level 140, a gaseous treatment medium can be introduced into the space above the bath level 140 either through the two nozzles 130 inside the tub 100 or through the blowing device 132. The preconditions for spotless drying of the spectacle lenses 122 are thus fulfilled. As a result and after a predetermined immersion time, the container 101 is lowered by the device 110. With the lowering of the container 101, the container is closed at the same time and moved into a lower position within the trough 100 (FIG. 8). This process takes place very quickly, within about 1 second. The space above the closed container 101 is filled by the gaseous treatment medium. The actual drying is then carried out by the blowing device 132. For this purpose, the blowing members 133, 134 and the nozzles 135, 136 are moved into a blowing position which corresponds to that shown in FIG. 2. The blowing of the spectacle lenses 122 takes place analogously to that described in connection with FIG. 2.

The fan 116 runs during the actual drying, but can already be put into operation if the atmosphere is to be generated from the treatment medium above the bath level 140 by the blowing device 132 in order to produce a uniform laminar suction flow within the space determined by the tub 100.

Claims (22)

1. Method for drying stainlessly of objects having flat surfaces and purified in a treatment liquid having predetermined degree of purity, said objects are immersed in substantially the same alignment in the treatment liquid, to achieve a homogeneous wetting of the surfaces of the objects, whereby the following steps are performed for drying:

a) a protective atmosphere with a gaseous treatment medium having predetermined degree of purity is established above the treatment liquid,

b) the treatment liquid is separated from the object after wetting, whereby a quick movement of separation results by lowering of the liquid, respectively of the bath, such that the released space around the objects is filled with gaseous treatment medium without time loss in order to avoid a contact with other gaseous mediums,

c) together with or immediately after the separation of treatment liquid and objects gaseous treatment medium is directed substantially coplanar to the surface of body of the objects and downwards to each object in order to blow off adherent liquid.

2. Method of claim 1, wherein said gaseous treatment medium is selected from the group pure nitrogen, purest nitrogen, inert gas, pure air or purest air.

3. Method of claim 1, wherein said treatment liquid is lowered by a container outlet of large cross section.

4. Method of claim 1, wherein said bath level is lowered by shifting the container containing the treatment liquid.

5. Method of claim 1, wherein said bath level is lowered within a period of about 0.1 to 5 seconds.

6. Method of claim 1, wherein said treatment liquid is drawn off.

7. Method of claim 1, wherein said objects are specifically blown upon from two directions simultaneously or sequentially.

8. Method of claim 1, wherein said objects are blown upon directly from two directions which enclose a predetermined angle.

9. Method of claim 7 or 8, wherein said objects are specifically blown upon from a direction which is changeable regarding said objects and from a further direction fixed regarding said objects.

10. Method of claim 1, wherein said blowing upon said objects is performed by pressure in the range of 1 - 8 bar.

11. Apparatus to perform the method of claim 1, which apparatus includes a holding device (32; 84, 121) for objects substantially in same alignment, a bath (1; 60; 101) having treatment liquid, a dip device (30, 31; 81-83) connected with said holding device (32; 84, 121) to convey and to move up and down continuously or gradually said holding device and to dip said objects (36; 91; 122) into said bath, a separating device (5; 64; 110) to separate said treatment liquid from said objects by lowering of the treatment liquid or of the bath, means (27-29; 40-49; 95-99; 131-135) which are connected with an external source (50; 99) of gaseous treatment medium in order to establish a protective atmosphere consisting of said gaseous treatment medium above said bath level, to maintain said protective atmosphere and to fill the liberated space around said objects with gaseous treatment medium after separation of treatment liquid and objects without time delay and a blowing device in order to simultaneously with and immediately after separation between treatment fluid and objects direct gaseous treatment medium substantially coplanar to body surface of the objects and downwardly onto each object in order to blow off adherent liquid.

12. Apparatus of claim 11, wherein said blowing device includes a first blowing means (40, 41; 59; 95) which is stationary with regard to objects to be dried and a second blowing means (42, 43; 57) which is movable to and fro with regard to said objects to be dried in order to blow upon specifically said objects to be dried from two directions, whereby said jets from said first and second blowing means define a predetermined angle.

13. Apparatus of claim 11, wherein said blowing device includes a first blowing means (59; 133, 134) and a second blowing means (57; 133, 134) which are simultaneously and timely displaced movable such that said jets from said blowing means run over said objects to blow upon said objects at set two directions.

14. Apparatus according to one of claims 12 and 13, wherein said blowing means is an elongated hollow body, whereby said outlet openings extend along a line over the longest part of the length of the hollow body.

15. Apparatus of claim 14, wherein said hollow body is a tube having a plurality of holes, which holes are disposed in distributed manner over the length of the tube and which holes are said outlet openings.

16. Apparatus of claim 14, wherein said hollow body is a channel having an outlet region, defining a gap in order to form and to guide the outlet jet such that a focussed jet is generated.

17. Apparatus according to one of the claims 12 or 13, wherein said blowing means is a nozzle (95).

18. Apparatus of claim 11, wherein said holding means (84) includes a device (90, 92, 93, 94, 94a) for moving said objects to be dried.

19. Apparatus of claim 18, wherein said device for moving said objects to be dried includes a drive means (94) mounted at the holding device (84); a driven means (9), onto which the objects (91) to be dried are placed, and which is movably mounted in said holding device (84), and which device includes a transfer means (92, 93, 94a) connecting said drive means with said driven means.

20. Apparatus of claim 11, wherein said bath includes a container (101) disposed in a vat (100), the upper part of said container (101) consists of two members (103, 104) pivotably mounted on the lower part (102) in order to shut said container, and a third device (110) is joined with said lower part (102) of the container (101) in order to move said container up and down, whereby said vat (100) is provided with strokes, each stroke being able to be brought in engagement with said members in order to open said container during the upward movement and to close said container during the downward movement.

21. Apparatus of claim 20, wherein a fan (116) is disposed within said vat in order to generate a guided suction within said vat (100), which suction supports said blowing off.

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