EP0084519A2 - Vessel containing an unstable solution of a metal salt or complex, and process for sealing such a vessel - Google Patents
Vessel containing an unstable solution of a metal salt or complex, and process for sealing such a vessel Download PDFInfo
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- EP0084519A2 EP0084519A2 EP83810011A EP83810011A EP0084519A2 EP 0084519 A2 EP0084519 A2 EP 0084519A2 EP 83810011 A EP83810011 A EP 83810011A EP 83810011 A EP83810011 A EP 83810011A EP 0084519 A2 EP0084519 A2 EP 0084519A2
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- Prior art keywords
- container
- seal
- sealing
- solution
- electrically conductive
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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
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
- C23F13/005—Anodic protection
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
- C25C7/06—Operating or servicing
Definitions
- the invention relates to an effective seal of a pressurized container, in the interior of which a shaft can be moved or rotated back and forth and which contains an unstable solution of a metal salt or complex.
- metal salt or complex solutions are unstable because, under certain conditions, the salt or complex decomposes and the metal precipitates out of the solution.
- Silver and copper salt or complex solutions in particular are particularly unstable.
- Pressurized containers inside which a reciprocating or rotatable shaft is provided, which can be used to mix or stir the contents of the container, require e.g. sealing means surrounding the shaft, which prevent the contents of the container from escaping where the shaft enters the container.
- sealing means surrounding the shaft, which prevent the contents of the container from escaping where the shaft enters the container.
- Various methods have been developed to achieve such a seal, such as the use of stuffing boxes and in particular lip seals and mechanical surface seals.
- all of these sealing methods require close contact between two surfaces, one of which rotates or reciprocates with respect to the other.
- a lip seal these are the surfaces of the lip seal itself and that of the shaft.
- a mechanical surface seal these are the surfaces of the two components of the seal, one of which is fixed and the other rotates with the shaft.
- Such sealing systems basically require the presence of a thin liquid film of the trapped liquid between the two surfaces, which film is an effective sealing medium. If such sealing systems are used in containers which contain unstable solutions of metal salts or complexes, it has been found that a decomposition of the liquid film takes place between the sealing surfaces, which leads to the precipitation of metal on the sealing surfaces and thus to excessive losses due to the escape of solution leads to the container.
- GB-PS 1 224 047 describes an anodic passivation process in which nickel is to be prevented by means of an alkaline solution and a porous partition from being deposited in undesired areas of a "nickel bath". This method may be effective for a nickel plating bath, but cannot be applied to a silver recovery cell in which an acidic solution is electrolyzed.
- the present invention now realizes a technical teaching in order to suppress fluid losses and to achieve an effective sealing of containers of the type mentioned at the outset.
- this is a mechanical surface seal, the immovable part of which consists of electrically conductive material.
- this is a lip seal made of an electrically conductive material.
- the method according to the invention is particularly applicable to a pressurized container which is used for the electrolytic recovery of metal and which contains a rotating electrode. It is also applicable to a pressurized container which consists of the pressure chamber of a pump.
- the method according to the invention is particularly advantageous in the case of unstable solutions of a silver salt or complex, since such solutions tend to be extremely unstable.
- the electrolytic recovery device comprises a cylindrical container V made of PVC.
- container V a rotatably mounted cathode C made of stainless steel is provided.
- the cathode C sits on a drive shaft S, which is mounted in a bearing B in the housing wall of the container V.
- a drive roller P is firmly seated on the shaft S and is connected to drive means (not shown) located outside the device.
- the cathode C is electrically connected via the shaft S.
- the drive means set the cathode C in the container V in rotation.
- the shaft S is sealed in the container V by means of a mechanical sealing system X, which consists of a rotating surface sealing element X 1 , which is fastened on the shaft S by means of a rubber bellows Be.
- the surface sealing element X 1 is in sealing contact with the counter surface sealing element X 20 which is attached to the upper housing part of the container V by means of an O-ring O.
- a graphite anode A is concentrically attached to the inner wall of the container V with the latter.
- a solution inlet Q leads from a solution reservoir (not shown) via a pump into the interior of the container V, and an outlet pipe R leads out of the container V.
- An electrical connecting line W connects the mating surface seal X 2 to the anode A.
- an aqueous solution containing metal ions is pumped through the inlet Q into the interior of the container V during neutral operation, while the cathode C and the anode A are formed via the electrical connection terminals U 1 and U 2 an electrical cell are connected to a current source U.
- the cathode C is rotated and the metal from the aqueous solution is deposited on the cathode.
- the aqueous solution is continuously pumped slowly into the container V through the inlet Q and leaves it again through the outlet R, so that the solution in the container V is constantly under pressure.
- a liquid-tight seal must be provided around the shaft S. If this is not the case, liquid creeps along the shaft and exits at the top of the container. This causes corrosion of the bearing B in contact with the solution, and also contamination, since the solution is forced out of the upper end of the container around the shaft in an uncontrollable manner. It is therefore necessary that the sealing elements X1 and X 2 together form a so-called "liquid seal".
- the rotating sealing surface element X 1 consisted of ceramic material and the fixed sealing surface element X 2 consisted of graphite.
- the cell was not connected to a power source, but water was let through the container V at a pressure of 1.01 bar and the cathode C at a speed of 1000 rpm. set in rotation. After 48 hours of continuous operation, no fluid loss from the container was found.
- the cell was also not connected to the power source, but a saline solution (100 g NaCl per liter) was continuously pumped through the container at a pressure of 1.01 bar and the cathode again at 1000 rpm. set in rotation. Again, after 48 hours of continuous operation, there was no loss of liquid in the container, because sodium chloride forms a stable salt solution.
- a saline solution 100 g NaCl per liter
- the cell was again not connected to the power source, but the fixing solution was pumped through the container under a pressure of 1.01 bar and the cathode at 1000 rpm. rotates. After three hours of operation, it was observed that liquid emerged from the container at the point of entry of shaft S into it. The operation was interrupted and the sealing elements X 1 and X 2 examined. It was found that metallic silver had deposited on both elements, causing a gap between the sealing surfaces and thus breaking the liquid seal.
- the same fixing solution was pumped through the same container under the same conditions and the cell was connected to the power source, but here the line W was connected to the anode A and to the electrically conductive sealing element X 2 .
- the experiment was then stopped and the container opened. Again, a deposit of silver in powder form was found on the cathode, but no deposit of silver metal or any other deposit on the surfaces of the two sealing elements X 1 and X 2 . In this case, the potential between the sealing element X 2 and the shaft was 1.5 V.
- Stainless steel is suitable as a further electrically conductive material for the fixed sealing element X 2 .
- the rotatable sealing element X 1 can also consist of graphite or stainless steel.
- Other suitable manufacturing materials are tungsten carbide and polytetrafluoroethylene. The preferred combination is graphite-graphite.
- the container represents an electrolytic cell, which is due to the potential difference between the sealing element X 2 and the Electrode generated current causes some silver metal to deposit on the cathode.
- the method used according to the invention for the protection of seals in other pressurized containers in which a shaft rotates or moves back and forth, so the dimensions of the counter-electrode and, if necessary electrical shielding of the electrically conductive sealing also the current flow can be limited to a minimum by the cell thus formed. This also keeps the amount of metal deposited on the counter electrode and any side effects on the solution in the container equally low.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Mechanical Engineering (AREA)
- Secondary Cells (AREA)
- Sealing Devices (AREA)
- Electrolytic Production Of Metals (AREA)
- Sealing Using Fluids, Sealing Without Contact, And Removal Of Oil (AREA)
Abstract
Die bewegte Welle (5) ist mittels einer Lippendichtung (X) durch eine Wand des Behältnisses (V) hindurchgeführt. Zur Vermeidung von unerwünschten Ablagerungen und damit zur Verminderung der Dichtwirkung ist die Lippendichtung aus elektrisch leitendem Material ausgebildet und an die Anode einer elektrischen Spannungsquelle (U) angeschlossen. Die Katode der Spannungsquelle (U) ist mit einer im Behältnis (V) angeordneten Gegenelektrode (C) verbunden.The moving shaft (5) is guided through a wall of the container (V) by means of a lip seal (X). To avoid unwanted deposits and thus to reduce the sealing effect, the lip seal is made of electrically conductive material and connected to the anode of an electrical voltage source (U). The cathode of the voltage source (U) is connected to a counter electrode (C) arranged in the container (V).
Description
Die Erfindung betrifft eine wirksame Abdichtung eines unter Druck stehenden Behältnisses, in dessen Innerem eine Welle hin und-her gehend bewegbar oder drehbar vorhanden ist und das eine instabile Lösung eines Metallsalzes oder -komplexes enthält.The invention relates to an effective seal of a pressurized container, in the interior of which a shaft can be moved or rotated back and forth and which contains an unstable solution of a metal salt or complex.
Viele Metallsalz- oder -komplexlösungen sind instabil, da sich unter gewissen Bedingungen das Salz oder der Komplex zersetzt und das Metall aus der Lösung ausfällt. Vor allem Silber- und Kupfersalz- oder -komplexlösungen sind besonders instabil.Many metal salt or complex solutions are unstable because, under certain conditions, the salt or complex decomposes and the metal precipitates out of the solution. Silver and copper salt or complex solutions in particular are particularly unstable.
Unter Druck stehende Behältnisse, in deren Innerem eine hin und her bewegbare oder drehbare Welle vorgesehen ist, die zum Mischen oder Rühren des Behältnisinhalts dienen kann, erfordern z.B. die Welle umgebende Dichtungsmittel, die verhindern, daß der Behältnisinhalt dort, wo die Welle in das Behältnis eintritt, entweichen kann. Zur Erzielung einer solchen Abdichtung wurden verschiedene Verfahren entwickelt, wie die Verwendung von Stopfbuchsen und insbesondere von Lippendichtungen und mechanischen Flächendichtungen. Jedoch erfordern alle diese Abdichtungsmethoden eine enge Berührung von zwei Flächen, von denen die eine sich gegenüber der anderen dreht oder hin und her bewegt. Im Falle einer Lippendichtung sind dies die Oberflächen der Lippendichtung selbst und diejenige der Welle. Im Falle einer mechanischen Flächendichtung sind dies die Oberflächen der beiden Komponenten der Dichtung, von denen die eine fest steht und die andere sich mit der Welle dreht.Pressurized containers, inside which a reciprocating or rotatable shaft is provided, which can be used to mix or stir the contents of the container, require e.g. sealing means surrounding the shaft, which prevent the contents of the container from escaping where the shaft enters the container. Various methods have been developed to achieve such a seal, such as the use of stuffing boxes and in particular lip seals and mechanical surface seals. However, all of these sealing methods require close contact between two surfaces, one of which rotates or reciprocates with respect to the other. In the case of a lip seal, these are the surfaces of the lip seal itself and that of the shaft. In the case of a mechanical surface seal, these are the surfaces of the two components of the seal, one of which is fixed and the other rotates with the shaft.
Solche Dichtungssysteme erfordern grundsätzlich das Vorhandensein eines dünnen Flüssigkeitsfilms der eingeschlossenen Flüssigkeit zwischen den beiden Oberflächen, wobei dieser Film ein wirkungsvolles Dichtungsmedium darstellt. Werden solche Dichtungssysteme bei Behältnissen verwendet, welche instabile Lösungen von Metallsalzen oder -komplexen enthalten, so wurde festgestellt, daß zwischen den dichtenden Flächen eine Zersetzung des Flüssigkeitsfilms stattfindet, die zum Niederschlag von Metall auf den Dichtungsflächen und damit zu starken Verlusten durch Entweichen von Lösung aus dem Behältnis führt.Such sealing systems basically require the presence of a thin liquid film of the trapped liquid between the two surfaces, which film is an effective sealing medium. If such sealing systems are used in containers which contain unstable solutions of metal salts or complexes, it has been found that a decomposition of the liquid film takes place between the sealing surfaces, which leads to the precipitation of metal on the sealing surfaces and thus to excessive losses due to the escape of solution leads to the container.
Das Auftreten der beschriebenen Undichtigkeit fällt besonders schwer ins Gewicht, wenn wässerige Lösungen von Silbersalzen oder Silberkomplexsalzen verwendet werden.The occurrence of the described leak is particularly difficult if aqueous solutions of silver salts or silver complex salts are used.
In der US-PS 3 910 833 wird ein elektrolytisches Silberwiedergewinnungsgerät beschrieben, das eine komplizierte und kostspielige Flüssigkeitsdichtungseinrichtung aufweist. In der US-PS 3 985 634 ist ebenfalls ein elektrolytisches Wiedergewinnungsbehältnis beschrieben, welches eine aus dünnen kreisförmigen Scheiben aus modifiziertem Tetrafluor- äthylen bestehende Dichtung enthält. Diese Scheiben bilden eine sehr wirksame Dichtung, die aber gleichwohl bei Niederschlag von Silber auf der Dichtung störanfällig ist.In U.S. Patent No. 3,910,833, an electrolytic silver recovery device is described which has a complicated and expensive liquid sealing device. US Pat. No. 3,985,634 also describes an electrolytic recovery container which contains a seal consisting of thin circular disks made from modified tetrafluoroethylene. These discs form a very effective seal, which is nevertheless prone to failure if silver is deposited on the seal.
In der GB-PS 1 224 047 wird ein anodisches Passivierungsverfahren beschrieben, in welchem Nickel mittels einer alkalischen Lösung und einer porösen Trennwand daran gehindert werden soll, sich in unerwünschten Bereichen eines "Vernickehngsbades" abzusetzen. Dieses Verfahren mag bei einem Vernickelungsbad wirksam sein, kann aber nicht bei einer Silberwiedergewinnungszelle angewandt werden, in welcher eine saure Lösung elektrolysiert wird.GB-PS 1 224 047 describes an anodic passivation process in which nickel is to be prevented by means of an alkaline solution and a porous partition from being deposited in undesired areas of a "nickel bath". This method may be effective for a nickel plating bath, but cannot be applied to a silver recovery cell in which an acidic solution is electrolyzed.
Die vorliegende Erfindung verwirklicht nun eine technische Lehre, um Flüssigkeitsverluste zu unterdrücken und um eine wirksame Dichtung von Behältnissen der eingangs erwähnten Art zu erreichen.The present invention now realizes a technical teaching in order to suppress fluid losses and to achieve an effective sealing of containers of the type mentioned at the outset.
Dies wird gemäß der vorliegenden Erfindung durch ein Verfahren der im Patentanspruch 1 und ein Behältnis der im Patentanspruch 2 beschriebenen Art, deren erfinderische Merkmale in den kennzeichnenden Teilen dieser Patentansprüche aufgeführt sind, erreicht.According to the present invention, this is achieved by a method of the type described in patent claim 1 and a container of the type described in patent claim 2, the inventive features of which are listed in the characterizing parts of these patent claims.
Gemäß einer Ausführungsform der Dichtung nach der Erfindung ist diese eine mechanische Flächendichtung, deren unbeweglicher Teil aus elektrisch leitendem Material besteht.According to one embodiment of the seal according to the invention, this is a mechanical surface seal, the immovable part of which consists of electrically conductive material.
Gemäß einer weiteren Ausführungsform der Dichtung nach der Erfindung ist diese eine aus elektrisch leitendem Material hergestellte Lippendichtung.According to a further embodiment of the seal according to the invention, this is a lip seal made of an electrically conductive material.
Das Verfahren nach der Erfindung ist besonders bei einem unter Druck stehenden Behältnis anwendbar, welches zur elektrolytischen Wiedergewinnung von Metall dient und eine rotierende Elektrode enthält. Weiter ist es anwendbar bei einem unter Druck stehenden Behältnis, welches aus der Druckkammer einer Pumpe besteht. Besonders vorteilhaft ist das Verfahren nach der Erfindung bei instabilen Lösungen eines Silbersalzes oder -komplexes anzuwenden, denn solche Lösungen haben die Neigung,äußerst instabil zu sein.The method according to the invention is particularly applicable to a pressurized container which is used for the electrolytic recovery of metal and which contains a rotating electrode. It is also applicable to a pressurized container which consists of the pressure chamber of a pump. The method according to the invention is particularly advantageous in the case of unstable solutions of a silver salt or complex, since such solutions tend to be extremely unstable.
Um das Verfahren nach der Erfindung zu verdeutlichen, wird auf die beiliegende Zeichnung Bezug genommen, deren einzige Figur eine Seitenansicht im Längsschnitt durch ein elektrolytisches Metallwiedergewinnungsbehältnis mit rotierender Kathode darstellt. Die wässerige, Metallionen enthaltende Lösung wird im Behältnis unter Druck umgewälzt.In order to clarify the method according to the invention, reference is made to the accompanying drawing, the sole figure of which shows a side view in longitudinal section through an electrolytic metal recovery container with a rotating cathode. The aqueous, containing metal ions Solution is circulated under pressure in the container.
Das elektrolytische Wiedergewinnungsgerät umfaßt einen aus PVC bestehenden zylindrischen Behälter V. Im Behälter V ist eine drehbar gelagerte Kathode C aus nichtrostendem Stahl vorgesehen. Die Kathode C sitzt auf einer Antriebswelle S, die in einem Lager B in der Gehäusewandung des Behälters V gelagert ist. Auf der Welle S sitzt eine Antriebsrolle P fest auf, die mit außerhalb des Geräts gelegenen (nicht gezeigten) Antriebsmitteln verbunden ist. Der elektrische Anschluß der Kathode C erfolgt über die Welle S. Die Antriebsmittel setzen die Kathode C im Behälter V in Drehung. Die Welle S ist im Behälter V mittels eines mechanischen DichtungssystemsX abgedichtet, welches aus einem rotierenden Oberflächendichtungselement X1 besteht, das auf der Welle S mittels eines Gummibalges Be befestigt ist. Das Oberflächendichtungselement X1 steht in dichtender Berührung mit dem Gegenflächendichtungselement X20 das am oberen Gehäuseteil des Behälters V mittels eines O-Ringes O befestigt ist.The electrolytic recovery device comprises a cylindrical container V made of PVC. In container V, a rotatably mounted cathode C made of stainless steel is provided. The cathode C sits on a drive shaft S, which is mounted in a bearing B in the housing wall of the container V. A drive roller P is firmly seated on the shaft S and is connected to drive means (not shown) located outside the device. The cathode C is electrically connected via the shaft S. The drive means set the cathode C in the container V in rotation. The shaft S is sealed in the container V by means of a mechanical sealing system X, which consists of a rotating surface sealing element X 1 , which is fastened on the shaft S by means of a rubber bellows Be. The surface sealing element X 1 is in sealing contact with the counter surface sealing element X 20 which is attached to the upper housing part of the container V by means of an O-ring O.
An der Innenwand des Behälters V ist mit diesem konzentrisch eine Graphitanode A befestigt.A graphite anode A is concentrically attached to the inner wall of the container V with the latter.
Ein Lösungseinlaß Q führt von einem Lösungsvorratsbehälter (nicht gezeigt) über eine Pumpe in das Innere des Behälters V, und ein Auslaßrohr R führt aus dem Behälter V heraus.A solution inlet Q leads from a solution reservoir (not shown) via a pump into the interior of the container V, and an outlet pipe R leads out of the container V.
Eine elektrische Verbindungsleitung W verbindet die Gegenflächendichtung X2 mit der Anode A.An electrical connecting line W connects the mating surface seal X 2 to the anode A.
Weiter unten wird das Material, aus welchem die Dichtungen X1 und X2 bestehen, noch näher beschrieben.The material from which the seals X 1 and X 2 are made is described in more detail below.
Ohne zunächst auf die elektrische Verbindungsleitung W einzugehen, wird bei neutralem Betrieb eine wässerige, Metallionen enthaltende Lösung durch den Einlaß Q in das Innere des Behälters V gepumpt, während die Kathode C und die Anode A über die elektrischen Anschlußklemmen Ul und U2 unter Bildung einer elektrischen Zelle an eine Stromquelle U angeschlossen sind. Die Kathode C wird in Drehung versetzt und das Metall aus der wässerigen Lösung auf der Kathode abgelagert. Die wässerige Lösung wird kontinuierlich langsam in den Behälter V durch den Einlaß Q hineingepumpt und verläßt ihn wieder durch den Auslaß R, so daß die Lösung im Behälter V ständig unter Druck steht.Without first going into the electrical connection line W, an aqueous solution containing metal ions is pumped through the inlet Q into the interior of the container V during neutral operation, while the cathode C and the anode A are formed via the electrical connection terminals U 1 and U 2 an electrical cell are connected to a current source U. The cathode C is rotated and the metal from the aqueous solution is deposited on the cathode. The aqueous solution is continuously pumped slowly into the container V through the inlet Q and leaves it again through the outlet R, so that the solution in the container V is constantly under pressure.
Um die Welle S herum muß eine flüssigkeitsdichte Abdichtung vorgesehen sein. Ist dies nicht der Fall, so kriecht Flüssigkeit längs der Welle und tritt am oberen Ende des Behälters aus. Dies verursacht eine Korrosion des mit der Lösung in Kontakt kommenden Lagers B, und außerdem eine Verschmutzung, da die Lösung aus dem oberen Ende des Behälters um den Schaft herum in unkontrollierbarer Weise herausgedrückt wird. Es ist daher erforderlich, daß die Dichtungselemente X1und X2 zusammen eine sogenannte "Flüssigkeitsdichtung" bilden.A liquid-tight seal must be provided around the shaft S. If this is not the case, liquid creeps along the shaft and exits at the top of the container. This causes corrosion of the bearing B in contact with the solution, and also contamination, since the solution is forced out of the upper end of the container around the shaft in an uncontrollable manner. It is therefore necessary that the sealing elements X1 and X 2 together form a so-called "liquid seal".
Hierbei bildet, während das auf der rotierenden Welle festsitzende Dichtungselement X1 in enger Berührung mit dem Dichtungselement X2 rotiert, ein dünner Flüssigkeitsfilm eine Flüssigkeitsdichtung zwischen den beiden Elementen, welche eine direkte Berührung zwischen den beiden Dichtungselementen verhindert und als Schmiermittel zwischen ihnen wirkt.Here, while the sealing element X 1 stuck on the rotating shaft rotates in close contact with the sealing element X 2 , a thin film of liquid forms a liquid seal between the two elements, which prevents direct contact between the two sealing elements and acts as a lubricant between them.
Ist jedoch eine instabile Lösung eines Metallsalzes oder -komplexes im Behälter vorhanden, so wurde festgestellt, daß diese Lösung dazu neigt,sich an der Stelle der Flüssigkeitsdichtung zu zersetzen, so daß Metall auf den Oberflächen der beiden Dichtungselemente X1 und X2 abgelagert. wird.However, if an unstable solution of a metal salt or complex is present in the container, it has been found that this solution tends to decompose at the location of the liquid seal so that metal is deposited on the surfaces of the two sealing elements X 1 and X 2 . becomes.
Dies verursacht eine Vergrößerung des Abstandes zwischen den Dichtungsflächen der beiden Elemente und gestattet den Zutritt von mehr Lösung an die Dichtungsstelle, was zur Folge hat, daß nun mehr Metall auf den Dichtungsflächen der beiden Elemente abgelagert wird, bis sie schließlich so weit auseinanderklaffen, daß keine Flüssigkeitsdichtung mehr bewirkt wird und die Flüssigkeit an der Welle entlang fließen kann.This causes an increase in the distance between the sealing surfaces of the two elements and allows more solution to enter the sealing location, with the result that more metal is now deposited on the sealing surfaces of the two elements until they finally diverge so far that none Liquid seal is more effected and the liquid can flow along the shaft.
Bei einem Vergleichsversuch bestand das rotierende Dichtungsflächenelement X1 aus keramischem Material und das feststehende Dichtungsflächenelement X2 aus Graphit.In a comparison test, the rotating sealing surface element X 1 consisted of ceramic material and the fixed sealing surface element X 2 consisted of graphite.
Bei einem Vorversuch wurde die Zelle nicht mit einer Stromquelle verbunden, jedoch Wasser durch den Behälter V mit einem Druck von 1.01 bar durchgelassen und die Kathode C mit einer Drehzahl von 1000 U./min. in Drehung versetzt. Nach 48 Stunden kontinuierlichem Betrieb wurden keine Flüssigkeitsverluste aus dem Behälter festgestellt.In a preliminary test, the cell was not connected to a power source, but water was let through the container V at a pressure of 1.01 bar and the cathode C at a speed of 1000 rpm. set in rotation. After 48 hours of continuous operation, no fluid loss from the container was found.
Bei einem zweiten Versuch wurde die Zelle ebenfalls nicht mit der Stromquelle verbunden, jedoch wurde eine Kochsalzlösung (lOOg NaCl je Liter) kontinuierlich unter einem Druck von 1.01 bar durch den Behälter gepumpt und die Kathode wiederum mit 1000 U./min. in Drehung versetzt. Wiederum wurde beim Behälter nach 48 Stunden kontinuierlichem Betrieb kein Flüssigkeitsverlust festgestellt, denn Natriumchlorid bildet eine stabile Salzlösung.In a second experiment, the cell was also not connected to the power source, but a saline solution (100 g NaCl per liter) was continuously pumped through the container at a pressure of 1.01 bar and the cathode again at 1000 rpm. set in rotation. Again, after 48 hours of continuous operation, there was no loss of liquid in the container, because sodium chloride forms a stable salt solution.
In einem dritten Versuch wurde eine Lösung eingesetzt, deren Zusammensetzung ungefähr derjenigen einer photographischen Fixierlösung entsprach und die je Liter:
- 0,5 mol Ammoniumthiosulfit
- O,1 mol Natriumsulfit
- 0,2 mol Essigsäure und
- 0,03 mol Silberbromid
- 0.5 mol ammonium thiosulfite
- 0.1 mol of sodium sulfite
- 0.2 mol of acetic acid and
- 0.03 mol of silver bromide
Die Zelle wurde wiederum nicht an die Stromquelle angeschlossen, jedoch die Fixierlösung unter 1.01 bar Druck durch den Behälter gepumpt und die Kathode mit 1000 U./min. rotiert. Nach drei Stunden Betrieb wurde beobachtet, daß Flüssigkeit aus dem Behälter an der Eintrittsstelle der Welle S in diesen austrat. Der Betrieb wurde unterbrochen und die Dichtungselemente X1 und X2 untersucht. Es wurde gefunden, daß auf beiden Elementen Ablagerung von metallischem Silber stattgefunden hatte, welche einen Spalt zwischen den Dichtungsflächen verursachte und damit die Flüssigkeitsdichtung aufgehoben hatte.The cell was again not connected to the power source, but the fixing solution was pumped through the container under a pressure of 1.01 bar and the cathode at 1000 rpm. rotates. After three hours of operation, it was observed that liquid emerged from the container at the point of entry of shaft S into it. The operation was interrupted and the sealing elements X 1 and X 2 examined. It was found that metallic silver had deposited on both elements, causing a gap between the sealing surfaces and thus breaking the liquid seal.
Bei einem vierten Versuch wurde die gleiche Fixierlösung unter den gleichen Bedingungen durch den gleichen Behälter gepumpt, jedoch in diesem Falle die Zelle an eine Stromquelle angeschlossen, wobei jedoch die Leitung W nicht mit dem Dichtungselement X2 verbunden war. Der Behälter arbeitete dann als eine Elektrolytzelle mit einer Stromdichte von 0,2 A·cm-2. Jedoch wurde nach zwei Stunden der Austritt von Flüssigkeit aus dem Behälter um die Welle S herum beobachtet. Der Versuch wurde dann unterbrochen und der Behälter geöffnet. Es wurde gefunden, daß sich metallisches Silber auf der Kathode C in Pulverform abgesetzt hatte. Auch wurden Ablagerungen von Silbermetall auf den Dichtungsflächen der beiden Elemente Xl und X2 .festgestellt.In a fourth experiment, the same fixing solution was pumped through the same container under the same conditions, but in this case the cell was connected to a power source, but the line W was not connected to the sealing element X 2 . The container then worked as an electrolyte cell with a current density of 0.2 A · cm -2 . However, after two hours the exit observed from liquid from the container around the shaft S. The experiment was then stopped and the container opened. It was found that metallic silver had deposited on the cathode C in powder form. Deposits of silver metal were also found on the sealing surfaces of the two elements X 1 and X 2 .
Beim fünften Versuch wurde die gleiche Fixierlösung unter den gleichen Bedingungen durch den gleichen Behälter gepumpt und die Zelle an die Stromquelle angeschlossen, aber hierbei die Leitung W mit der Anode A und mit dem elektrisch leitenden Dichtungselement X2 verbunden. In diesem Falle konnte sogar nach 48 Stunden ununterbrochenem Betrieb kein Flüssigkeitsverlust aus dem Behälter beobachtet werden. Der Versuch wurde dann unterbrochen und der Behälter geöffnet. Wiederum wurde auf der Kathode eine Ablagerung von Silber in Pulverform festgestellt, jedoch kein Niederschlag von Silbermetall oder irgendeiner anderen Ablagerung auf den Flächen der beiden Dichtungselemente X1 und X2. In diesem Falle betrug das Potential zwischen dem Dichtungselement X2 und der Welle 1,5 V.In the fifth experiment, the same fixing solution was pumped through the same container under the same conditions and the cell was connected to the power source, but here the line W was connected to the anode A and to the electrically conductive sealing element X 2 . In this case, no liquid loss from the container was observed even after 48 hours of uninterrupted operation. The experiment was then stopped and the container opened. Again, a deposit of silver in powder form was found on the cathode, but no deposit of silver metal or any other deposit on the surfaces of the two sealing elements X 1 and X 2 . In this case, the potential between the sealing element X 2 and the shaft was 1.5 V.
Als weiteres elektrisch leitendes Material für das feststehende Dichtungselement X2 ist nichtrostender Stahl geeignet. Das drehbare Dichtungselement X1 kann ebenfalls aus Graphit oder nichtrostendem Stahl bestehen. Andere geeignete Herstellungsmaterialien sind Wolframkarbid und Polytetrafluoräthylen. Die bevorzugte Kombination ist Graphit-Graphit.Stainless steel is suitable as a further electrically conductive material for the fixed sealing element X 2 . The rotatable sealing element X 1 can also consist of graphite or stainless steel. Other suitable manufacturing materials are tungsten carbide and polytetrafluoroethylene. The preferred combination is graphite-graphite.
In dem zuletzt beschriebenen Versuch stellt der Behälter eine elektrolytische Zelle dar, und der durch die Potentialdifferenz zwischen dem Dichtungselement X2 und der Kathode erzeugte Strom verursacht,daß sich etwas Silbermetall auf der Kathode ablagert. Wird jedoch das Verfahren nach der Erfindung zum Schutze von Dichtungen in anderen unter Druck stehenden Behältnissen verwendet, in welchen eine Welle sich dreht oder sich hin und her bewegt, so können die Abmessungen der Gegenelektrode und erforderlichenfalls durch elektrische Abschirmung der elektrisch leitenden Dichtung auch der Stromfluß durch die so gebildete Zelle auf ein Mindestmaß beschränkt werden. Hierdurch wird auch die Menge des auf der Gegenelektrode abgesetzten Metalls sowie etwaige Nebenwirkungen auf die Lösung im Behälter gleichermaßen niedrig gehalten.In the experiment described last, the container represents an electrolytic cell, which is due to the potential difference between the sealing element X 2 and the Electrode generated current causes some silver metal to deposit on the cathode. However, if the method used according to the invention for the protection of seals in other pressurized containers, in which a shaft rotates or moves back and forth, so the dimensions of the counter-electrode and, if necessary electrical shielding of the electrically conductive sealing also the current flow can be limited to a minimum by the cell thus formed. This also keeps the amount of metal deposited on the counter electrode and any side effects on the solution in the container equally low.
Claims (7)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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GB8201366 | 1982-01-19 | ||
GB8201366 | 1982-01-19 |
Publications (3)
Publication Number | Publication Date |
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EP0084519A2 true EP0084519A2 (en) | 1983-07-27 |
EP0084519A3 EP0084519A3 (en) | 1983-08-03 |
EP0084519B1 EP0084519B1 (en) | 1985-12-18 |
Family
ID=10527698
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP83810011A Expired EP0084519B1 (en) | 1982-01-19 | 1983-01-13 | Vessel containing an unstable solution of a metal salt or complex, and process for sealing such a vessel |
Country Status (4)
Country | Link |
---|---|
US (1) | US4545873A (en) |
EP (1) | EP0084519B1 (en) |
JP (1) | JPS58128138A (en) |
DE (1) | DE3361502D1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2639961A1 (en) * | 1988-11-28 | 1990-06-08 | Lobry Andre | Device for protecting surfaces in contact with liquid against scaling or corrosion |
FR2657089A1 (en) * | 1990-01-16 | 1991-07-19 | Lobry Andre | Protection against scaling and corrosion of surfaces in contact with liquids |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4889608A (en) * | 1987-02-10 | 1989-12-26 | Pine Instrument Company | Electrode system |
US7481922B2 (en) * | 2004-01-05 | 2009-01-27 | Edward Horton Madden | Fluid treatment apparatus |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1224047A (en) * | 1968-12-10 | 1971-03-03 | Tsniitmash | Method of inhibiting the formation of a coating on chemical equipment |
US3910833A (en) * | 1974-09-26 | 1975-10-07 | David R Knighton | Apparatus for recovering silver from photographic film processing liquids |
US3985634A (en) * | 1975-01-27 | 1976-10-12 | Larson Kay R | Electrolytic silver recovery apparatus |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3240685A (en) * | 1962-02-23 | 1966-03-15 | Ibm | Method and device for selective anodization |
NL297569A (en) * | 1962-09-06 | |||
US3169504A (en) * | 1963-12-16 | 1965-02-16 | Wankesha Bearings Corp | Cathodic system |
US3429799A (en) * | 1966-05-31 | 1969-02-25 | Monsanto Co | Fluid-tight electrical connections for electrolytic cells |
US3486999A (en) * | 1967-11-02 | 1969-12-30 | Leonard F Craft | Apparatus for preventing scale formation in water systems |
FR2327326A1 (en) * | 1975-10-08 | 1977-05-06 | Solvay | PROCESS FOR THE HANDLING OF AQUEOUS SOLUTIONS OF ALKALINE METAL HYDROXIDES CONCENTRATED IN ALKALINE METAL HALOGENIDES |
US4113600A (en) * | 1977-04-21 | 1978-09-12 | A. O. Smith Corporation | Flue pipe anode ring for water heater |
-
1983
- 1983-01-10 US US06/456,895 patent/US4545873A/en not_active Expired - Fee Related
- 1983-01-13 DE DE8383810011T patent/DE3361502D1/en not_active Expired
- 1983-01-13 EP EP83810011A patent/EP0084519B1/en not_active Expired
- 1983-01-18 JP JP58005388A patent/JPS58128138A/en active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1224047A (en) * | 1968-12-10 | 1971-03-03 | Tsniitmash | Method of inhibiting the formation of a coating on chemical equipment |
US3910833A (en) * | 1974-09-26 | 1975-10-07 | David R Knighton | Apparatus for recovering silver from photographic film processing liquids |
US3985634A (en) * | 1975-01-27 | 1976-10-12 | Larson Kay R | Electrolytic silver recovery apparatus |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2639961A1 (en) * | 1988-11-28 | 1990-06-08 | Lobry Andre | Device for protecting surfaces in contact with liquid against scaling or corrosion |
FR2657089A1 (en) * | 1990-01-16 | 1991-07-19 | Lobry Andre | Protection against scaling and corrosion of surfaces in contact with liquids |
Also Published As
Publication number | Publication date |
---|---|
DE3361502D1 (en) | 1986-01-30 |
US4545873A (en) | 1985-10-08 |
JPS58128138A (en) | 1983-07-30 |
EP0084519B1 (en) | 1985-12-18 |
EP0084519A3 (en) | 1983-08-03 |
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