EP1771681B1 - Transfer container - Google Patents

Description

The present invention relates to a container for transferring a liquid, solid or gaseous substance into a closed system, comprising a housing having at least one vacuum-tightly closed opening, wherein the substance to be transferred is contained in the housing and a method for its production.

The introduction of highly pure reactive or stable materials, such as. B. non-evaporative getter in bulk form, is nowadays without saturation by contact with the ambient atmosphere or a load on the atmosphere of the closed system by loose particles today usually can not cope. Numerous applications therefore require complicated transfer systems, complex processes or special pre-processing of the substances to be introduced. On the one hand, the materials to be introduced often have to be elaborately protected against contamination by contamination or mixing with the ambient atmosphere and, on the other hand, the release of the material in the highest purity in the vacuum range or in an inert atmosphere at a certain time must be ensured by a corresponding opening mechanism.

Most of these requirements are solved by transfer chambers or low-performance material combinations, which in addition to a not inconsiderable cost factor also requires several time-consuming assembly or process steps.

Non-evaporating getters (NEGs) use different starting materials today. Alkali / alkaline earth metals are suitable as powerful getter sources, but are difficult to handle due to their high reactivity ( Scientific Foundations of Vacuum Technique, John Willey & Sons, New York (1962), p. 622 ; della Porta, Vacuum, 1996, 47: 771 ).

Therefore, in the NEG environment mainly Zr, V and Fe mixtures are used, which in addition to a low sorption capacity also have only a low sticking rate (retention time) of the absorbed residual gases (see, for. BP della Porta, Technical Paper TP 202, 1992 ; US 6,506,319 ; US 6,672,819 ; US 6,420,002 ; US 6,514,430 ; US 6,322,720 ; US 6,200,494 ; Ferrario, Vacuum 47 (1996), p. 363 ; US 6,322,720 ).

Existing containers for the transfer of liquid, solid or gaseous substances into closed systems use lacquers or volatile coatings which are opened either by means of temperature or chemical reactions (eg. EP 0 511 177 A ), whereby these applications are due to the outgassing behavior of the substances used only conditionally suitable for the UHV or XHV range.

Mechanical opening mechanisms, which either respond to the changing pressure when pumping out a vacuum chamber or are opened by applying force from the outside, are elaborately constructed and usually change when opening the total pressure in the container and are therefore only conditionally usable ( PCT / EP02 / 01409 ).

In the publication US 2003/0196311 A1 discloses a sealed dewar unit that includes a getter and is evacuated via a flange and then hermetically sealed in this area with a cap that mates with the flange, with an indium gasket between the flange and cap. A structure of the provided in the Dewar unit getter is not addressed. In addition, the Dewar unit is fully completed and remains in this condition as appropriate.

The invention thus has the object to overcome the above-mentioned problems and difficulties of the prior art and to provide a container of the type mentioned, with the help of sensitive materials, in particular high purity and highly reactive materials, such as getter materials, in sealed systems and applications, vacuum chambers , Pressure chambers, etc. in a simple manner in predetermined amounts can be introduced at an arbitrary time without endangering the purity of the system. In addition, this container should be relatively inexpensive and can be produced without time-consuming and labor-intensive production steps.

This object is achieved by a container according to claim 1

Upon heating the container of the invention to a certain temperature, which is a function of the material of the gasket, the metal of the gasket is melted and the transferred substance is transferred to the environment, i. in the closed system, released.

The container according to the invention can thus be used in the entire field of vacuum technology, in which high-purity materials, eg. As metals, introduced and vaporized or different getter materials are released to improve the vacuum. In the field of overpressure applications, which must be completed in closed cycles, the invention also makes it possible to introduce highly pure liquid, solid or gaseous substances, materials and components. In combination z. B. in the field of lamp manufacturing by noble gases and getter materials are released at the same time to ensure the best possible purity of the reaction space and the release of the exact amount of gas required in only one process step.

Depending on the desired release temperature, different metals or alloys can be used for the seal. The temperature-dependent seal is selected from metals of the group consisting of Ga, In, Sn, Pb and their alloys.

According to a preferred embodiment of the invention, the temperature-dependent seal has a melting point in the range of 50 ° C to 350 ° C.

Advantageously, the temperature-dependent seal in the non-pressed state has an average thickness in the range of 2-5 mm.

A further preferred embodiment is characterized in that the housing comprises, following the temperature-dependent seal, a further section which is provided with gas-permeable, but solids-impermeable openings, preferably slots. Suitably, the openings are closed with a fine-meshed network or a gas-permeable membrane.

In the field of getter applications, it often makes sense that the getter material after melting the seal in the getter housing, i. in the transfer container remains. After the container has been opened by melting the seal, a gas exchange can take place according to the invention through the openings in the section following the seal without loose particles of the getter material emerging from the container.

Preferably, the substance to be transferred is a getter material.

It is also particularly advantageous if the housing of the container is cylindrical or cuboidal. However, other forms are conceivable.

The method for producing a container according to the invention with two openings is characterized in that an opening of the housing with a preformed temperature-dependent, melting at a release temperature seal made of metal is vacuum sealed by the seal pressed on opposite sides simultaneously with compression and lateral expansion of the metal is, the substance to be transferred, optionally under vacuum or inert atmosphere, then introduced into the housing and the other opening is then sealed vacuum-tight.

The second opening is preferably closed by welding, mechanical interference fit or an adhesive.

The material of the housing is chosen according to the application. In the field of vacuum and overpressure applications, stainless steel, ceramic or glass containers are particularly suitable due to the low outgassing and high tightness. The shape of the housing is not limited, as long as appropriate pressing tools guarantee the exact pressing and thus the tightness of the container.

The tightness and the load capacity of the temperature-dependent seal depends on the starting material, the material density in the raw state and the compression during the pressing process and the surface to be sealed or the respective inner diameter of the release outlet. Preferred sealing materials are Ga, In, Sn, Pb or their alloys, such as. B. InSn.

For the test series with a steel tube with an internal diameter of 7.2 mm and a wall thickness of 0.5 mm, between 35 mg and 45 mg in pure or a homogeneous InSn alloy were used. For larger sealing surfaces, even with stable spacers (rings, discs or rectangles made of steel, ceramic, glass) additional stabilization of the seal can be achieved.

The other opening of the container is closed after filling with the substance to be transferred so as to ensure that it can not open when the container is heated. Different materials can be used. Depending on the application, different techniques can be used. In the examples, the end z. B. mechanically compressed to 1.5 mm by means of a screw press and then welded off electrically vacuum-tight.

As mentioned above, in many applications, it is desired that the material remain within the container. Remains z. As the getter after melting the seal in Gettergehäuse, the respective vacuum chamber or application is protected from loose particles. Through a fine-meshed network and in succession through a gas-permeable membrane, this part of the getter chamber is connected to the atmosphere of the vacuum chamber or the closed cavity to be cleaned and can thereby develop the desired sorption performance.

1. 1.) Je nach gewünschter Freigabetemperatur wird eine Dichtung aus entsprechenden Reinmetallen wie Ga, In, Sn, Pb bzw. aus deren Legierungen hergestellt.
2. 2.) Mit einer Pressvorrichtung wird das Transferbehältnis, das zwei Öffnungen aufweist z. B. bei zylindrischem Gehäuse an beiden Enden offen ist an einer Öffnung bzw. einem Ende mit der vorgeformten, temperaturabhängigen Dichtung mechanisch dicht verschlossen.
3. 3.) Dann wird der gewünschte flüssige, feste oder gasförmige Stoff eingebracht. Dies kann, wenn notwendig, in einer Schutzgasatmosphäre oder im Vakuum (Glove Box oder Ähnliches) durchgeführt werden.
4. 4.) Danach wird der Behälter entweder evakuiert oder mit der im Behälter befindlichen Atmosphäre unter Verhinderung einer Kontamination des Inhaltes dicht abgeschweißt, mechanisch (dichte Presspassung) oder chemisch in Form eines Klebers verschlossen.
5. 5.) Durch direktes oder indirektes Erhitzen des Transferbehältnisses auf die wählbare Freigabetemperatur schmilzt die Dichtung und der vorbefüllte Stoff wird freigesetzt. Bei festen Stoffen kann das Freisetzen auch durch einen vorgespannten Federmechanismus oder einen Subkontainer unterstützt werden.
6. 6.) Bei vielen Getteranwendungen ist es wünschenswert und sinnvoll, dass das Gettermaterial nach Aufschmelzen der Dichtung im Gettergehäuse verbleibt und durch eine gasdurchgängige, aber lose Partikel aufhaltende Öffnung mit der Atmosphäre in der Anwendung verbunden ist. Die Öffnung(en) ist (sind) dabei in einem Bereich des Gettergehäuses angeordnet, der vorher nicht durch die Dichtung geschützt war.

Principle and function of the invention:

1. 1.) Depending on the desired release temperature, a seal is made from corresponding pure metals such as Ga, In, Sn, Pb or from their alloys.
2. 2.) With a pressing device, the transfer container having two openings z. B. in a cylindrical housing open at both ends is mechanically sealed at an opening or an end with the preformed, temperature-dependent seal.
3. 3.) Then the desired liquid, solid or gaseous substance is introduced. This may be carried out in a protective gas atmosphere or in a vacuum (glove box or the like) if necessary.
4. 4.) Thereafter, the container is either evacuated or tightly sealed with the atmosphere in the container while preventing contamination of the contents, mechanically (tight interference fit) or chemically sealed in the form of an adhesive.
5. 5.) By directly or indirectly heating the transfer container to the selectable release temperature, the seal melts and the pre-filled substance is released. For solids, release may also be assisted by a preloaded spring mechanism or a subcontainer.
6. 6.) In many getter applications, it is desirable and meaningful that the getter material remains in the getter housing after melting the seal and is connected by a gas-permeable, but loose particle-containing opening with the atmosphere in the application. The opening (s) is (are) located in a region of the getter housing that was not previously protected by the seal.

• das Einbringen exakter Mengen von festen, flüssigen oder gasförmigen Stoffen in Vakuum- Normal- und Überdruckumgebung;
• die Freisetzung der zu transferierenden Stoffe durch thermische Öffnung der Dichtung zu einem exakten, frei wählbaren Zeitpunkt;
• eine Steuerung des Freisetzungszeitpunktes durch Erwärmung des Behältnisses, der Kammer, des Bautelles oder der Anwendung,
• eine exakte Steuerung des thermischen Freisetzungsmechanismus mit wählbaren Temperaturen im Bereich von 50°C bis 350°C;
• einen Prozessablauf ohne spezielle Öffnung der Vakuumkammer, der Druckkammer, der Anwendung oder des Bauteiles;
• das Einbringen und den Einsatz von Gettermaterialien in Vakuum bzw. Inertumgebung, die beim Einbringen chemisch aktiv sein können, in loser Form sein können bzw. bei ihrem Einsatz lose Partikel erzeugen können.

The invention thus has the following advantages:

• the introduction of exact quantities of solid, liquid or gaseous substances in a vacuum normal and overpressure environment;
• the release of the substances to be transferred by thermal opening of the seal at a precise, freely selectable time;
• a control of the release time by heating the container, the chamber, the construction table or the application,
• precise control of the thermal release mechanism with selectable temperatures in the range of 50 ° C to 350 ° C;
• a process sequence without special opening of the vacuum chamber, the pressure chamber, the application or the component;
• the introduction and use of getter materials in vacuum or inert environment, which may be chemically active during introduction, may be in loose form or may produce loose particles when used.

The invention will be explained in more detail by means of examples and the drawing, wherein Fig. 1 the process of generating the temperature-dependent seal of the container according to the invention, Fig. 2 the process of filling and closing the other opening of the container according to the invention, Fig. 3 the application of the container according to the invention in a closed chamber and Fig. 4 an embodiment of the container according to the invention for the transfer of getter materials illustrated.

According to Fig. 1 a) is a cylindrically preformed temperature-dependent seal 4 made of metal, for. B. from Ga, In, Sn, Pb or alloys thereof, arranged at an opening 2 of a cylindrical housing 1. Thereafter, the seal 4 by a pressing device 8, which simultaneously exerts pressure on the two opposite base surfaces of the sealing cylinder, pressed (Fig. 1 b)). By compression and lateral expansion of the seal 4, a vacuum-tight closure of the opening 2 of the housing 1 is achieved. The one-sided sealed container with the pressed seal 4 is shown in Fig. 1 c).

According to Fig. 2 a), the housing 1 is then filled with the substance to be transferred 5 (shown in the solid state). The two further illustrations each show a type of closure of the other (second) opening 3 of the housing 1. In Fig. 2 b), the opening 3 is sealed vacuum-tight with a suitable material by means of press fitting. Fig. 2 c) shows a sealed container, which was pressed at its still open end and then electrically welded.

In Fig. 3 a), a cylindrical chamber 9 (vacuum or pressure chamber) is shown, on whose inner wall the inventive (filled and sealed) transfer container is arranged. By heating the container (represented by arrows) melts the temperature-dependent gasket 4 made of metal and thus releases the opening 2 of the housing 1, whereby the transferred substance 5 is released from the housing 1 (Fig. 3 b)).

Fig. 4 shows an example of a transfer container according to the invention a Getterspeicher in the form of a tube 10. Between the two vacuum-tightly welded tube ends 11 and 12, the temperature-dependent seal 4 is arranged, the seat by a slight constriction of the tube 10 can be seen. Between the seal 4 and the pipe end 11 is the material depot 13, in which a particulate getter material is housed. Below the seal 4, ie between the seal 4 and the pipe end 12, the tube 10 has a plurality of slot-shaped openings 7, which are closed by a fine-meshed network. This tube section 6 serves as an active depot after the melting of the seal and the release of the getter.

Example 1:

To produce the transfer container according to the invention, a tubular Gettergehäuse stainless steel was used with a length of 100 mm, a wall thickness of 0.5 mm and an inner diameter of 7.2 mm.

Slots were placed below the planned position of the gasket and closed with a gas-permeable but particulate-retentive mesh. The sealant used was a fit of pure indium (50 mg).

The indium fitting was positioned at the desired location (30 mm from a pipe end) and then evenly compacted from both sides by simultaneous pressing with tools. Due to the resulting material expansion of the indium at the sealing edge, there was a tight connection with the container inner wall and thus to a vacuum-tight seal.

The sealed tube was filled in a glove box with a getter mixture. The open end of the tube was sealed by means of a hose clamp, discharged from the glove box and evacuated on a vacuum pump in the range of 10 ^-5 m bar. Then, the hose clamp was closed again to secure the vacuum, and the pipe end was pressed with a screw press 3 cm after the hose clamp and then electrically welded.

Subsequently, the thus sealed Gettergehäuse was fixed to the inner wall of a vacuum chamber. After establishing the initial vacuum, the getter storage was heated from the outside by means of industrial heating via the heat transfer of the vacuum chamber wall to 168 ° C over a period of 2 minutes.

The pressed indium seal then melted, d. H. The getter material slid into the lower part of the housing and was now able to fulfill its task of sorption of residual gases. Due to the gas-permeable network used, no disturbing loose getter particles could enter the atmosphere of the vacuum chamber.

Example 2:

Same construction as in Example 1. As the sealing material, however, an InSn alloy whose mass was 80 mg was used.

After establishing the initial vacuum, the getter storage was externally heated to 137 ° C via heat transfer from the vacuum chamber wall over a period of 2 minutes. The pressed InSn seal then melted, causing the getter storage to open and release the getter material.

Claims (9)

1. A container for transferring a liquid, solid or gaseous substance (5) into a closed system, comprising a housing (1) with at least one opening (2, 3) which is closed in a vacuum-type manner, wherein the substance (5) to be transferred is contained in the housing (1), characterised in that the at least one closed opening (2, 3) is closed with a temperature-dependent seal (4) melting at a release temperature and made from a metal selected from the group comprising Ga, In, Sn, Pb and their alloys, so that the substance (5) can be released by melting of the seal (4).
2. The container according to claim 1, characterised in that the temperature-dependent seal (4) has a melting point in the range from 50°C to 350°C.
3. The container according to claim 1 or 2, characterised in that the temperature-dependent seal (4) in the non-compressed state has an average thickness in the range from 2-5 mm.
4. The container according to any one of claims 1 to 3, characterised in that the housing (1), following the temperature-dependent seal (4), comprises a further section (6) which is provided with gas-permeable, but solid-impermeable openings (7), preferably slits.
5. The container according to claim 4, characterised in that the openings (7) are closed with a fine-mesh net or a gas-permeable membrane.
6. The container according to any one of claims 1 to 5, characterised in that the substance (5) to be transferred is a getter material.
7. The container according to any one of claims 1 to 6, characterised in that the housing (1) is formed cylindrical or rectangular-shaped.
8. A method for producing a container according to any one of claims 1 to 7 with two openings, characterised in that one opening (2) of the housing (1) is closed in a vacuum-tight manner with a preformed temperature-dependent seal (4) made of metal and melting at a release temperature, wherein the seal (4) is pressed simultaneously on opposite sides thereby becoming compressed with a lateral expansion of the metal, the substance (5) to be transferred, optionally under a vacuum or an inert atmosphere, is then introduced into the housing (1) and the other opening (3) is then closed in a vacuum-tight manner.
9. The method according to claim 8, characterised in that the second opening (3) is closed by welding, mechanical press-fit or an adhesive.

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