EP0060289B1 - Reactive anode with consumption indicator and diving capsule for a heat probe - Google Patents

Description

The invention relates to a sacrificial anode with consumption indicator for the cathodic corrosion protection of static or operating pressurized water containers and water heaters and for containers of other, also electrically conductive media and has the purpose of simplifying sacrificial anodes with consumption indicator with regard to manufacture and their interchangeability on a container and - in the event of elimination of a movable display element of the consumption display - to adapt the installation, maintenance and control conditions in the mentioned area of application in a practical manner.

The invention also relates to the structural connection of the sacrificial anode according to the invention to an immersion sleeve for receiving a so-called "heat sensor" in one piece, with the aim of having both control devices equipped with a sacrificial anode and at least one heat sensor using a single screwing process or the like . Like. to be able to insert into one and the same container opening.

In the case of the already known sacrificial anodes with consumption indicator, the latter essentially consists of a pin-like organ which is longitudinally displaceable within a cavity of the anode and / or anode screw connection, which is displaced towards the container wall when the anodic material is used up and when the container medium penetrates into the cavity, and as Consumption signal from the front of the anode screw connection and thus emerges from the container.

Sacrificial anodes of this type have proven themselves in many areas of application for cathodic container corrosion protection and have found their way into practice over a wide area. They are able to actuate remotely installed display means by mechanical or electrical means by means of the pen-like organ. From an economic point of view, such sacrificial anodes with consumption indicators are disadvantageous, particularly in the case of the serial factory equipment of small and medium-sized containers with such sacrificial anodes, since their production price for this container series article, for which a particularly favorable overall price must be sought, in one unfavorable ratio. The display mechanism in the form of the pin-like, longitudinally displaceable member requires, in particular because of the assembly activity required here, a higher manufacturing and thus a higher cost. It also has an expensive effect that, for design-related reasons, the anode rod and the anode screw connection containing the consumption indicator have to be connected with the laborious manual addition of a liquid sealant, which also leads to the application or maintenance disadvantage that when the actual anode rod is used up, the entire anode also has to be connected Consumption indicator must be replaced and not - in a far more economical way - only the anode rod. Finally, especially in the case of small containers, in particular water heaters, it is desirable to avoid parts that protrude from the container contour when the consumption is displayed, the meaning of which, when viewed briefly, in particular by laypersons, is not always recognized as the result of the display.

In order to be able to determine the consumption of sacrificial anodes outside the container without a consumption display integrated in the anode, an arrangement has also become known in which an electrical measurement, e.g. Current measurement, by comparing anode volume values with corresponding electrical values, conclusions can be drawn about the state of consumption of the anode rod. Here, the sacrificial anode must be electrically insulated from the container, screwed into the container and, to maintain the function of the cathodic corrosion protection with the container, via a detachable wire line or the like. be connected. If a measurement is to be made, the wire or the like is. solved and interposed an electrical measuring device. Such a test procedure is cumbersome and time consuming. It can only be carried out by a specialist. In addition, a comparison table or the like is available for each anode size. with opposite anode volume values and electrical values.

Containers of the type mentioned generally have to be equipped with a heat control device, a heat sensor, if they contain heated media. Since such containers are usually also equipped with a sacrificial anode, manual interventions such as drilling, welding and the like are required at two points in the container with considerable expenditure of time and money. to make both devices in the container in their effective position. For example, a tube that is closed at one end, the immersion sleeve, is let in for the heat sensor through a hole in the container and is welded to the hole with its open end face, which is then or the like at its insertion opening by a stopper. heat sensor to be secured and for the sacrificial anode, a further hole is made in the container wall, which in most applications is to be provided with a threaded sleeve by welding. A juxtaposition of two identical work processes at different points in the container for a similar introduction of two control devices into the same container is extremely uneconomical and contradicts the current efforts to rationalize and reduce costs.

The invention has for its object that when using the known sacrificial anodes with consumption indicator for water tanks and water heaters, especially small and Medium containers to eliminate existing disadvantages and also to find a solution to be able to mount both control devices in one and the same container bore while equipping a container with a sacrificial anode and a heat sensor.

According to the invention, this is achieved with respect to the sacrificial anode in that instead of a pin-like, longitudinally displaceable display element, two externally accessible, penetrating the anode screw connection, electrically insulated from one another and reaching into an end cavity of the anode rod, but at least spatially connected to it, are arranged enable the connection of an optically and / or acoustically acting electrical signal device at their externally accessible ends, and which, with their other ends spatially connected to the cavity of the anode rod, act as an electrical switch as soon as the anode rod is used up, thereby containing water in the container Cavity penetrates, wets or surrounds the contact parts and thereby closes electrically.

The effectiveness of the switch bridge formed by container water depends on two criteria governed by the invention, which can be seen in the ratio of the electrical conductivity of water: contact distance: test voltage and in the air column in the cavity, which counteracts the entry of water.

Starting from a constant electrical conductivity of the water, e.g. with a relatively low test voltage, which according to safety regulations has to be in the low-current range, a relatively small contact distance should be selected, whereas a higher test voltage, e.g. in favor of a greater mechanical robustness of the contact ends of the contact parts, a larger contact distance allowed. If a functional relationship between the test voltage and the contact distance cannot be maintained, the electrical conductivity of the water can be determined by using a tableted, suitable agent such as salt, e.g. NaCI, for example between the contact ends and the anode rod, which agent dissolves when water enters it.

The other criterion is based on the fact that the air can be compressed depending on the pressure of the container medium and the compression limit. When using the sacrificial anode for containers that are subject to a higher pressure (mostly containers with operating pressure), the contact ends may therefore have a calculable greater distance from the potential water entry point, whereas when using them for containers with low pressure (mostly containers with static pressure) ) the contact ends are to be brought close to the potential water entry point. On the manufacturing side, the last-mentioned embodiment provides the need to shorten the iron core present in the anode rod within the cavity in the anode rod, so that in the case of containers with higher pressures, sacrificial anodes with the greater distance from the potential water entry point are to be preferred.

The electrical signal device can be connected to the contact ends accessible from the outside of a container either by means of a permanently connected circuit of an optical and / or acoustic signal fed by the secondary side of a mains transformer, or by a connection contacts against the contact ends of the, if required Manual device to be pressed with an optical and / or acoustic signal device and its own battery power source, which corresponds to the mode of operation of an ohmmeter or a continuity tester. Such a manual device is particularly suitable for use by laypeople if a forced removal of contacts to counterpress the device is provided, which excludes contact removal errors, and since the meaning of the signal types mentioned when they take effect cannot be misunderstood. The contact parts of the sacrificial anode can be designed from the outset for one or the other type of consumption display.

The principle according to the invention, while taking into account a detachable, self-sealing attachment of the anode rod to the anode screw connection, enables a very simple, economical and therefore inexpensive production of a sacrificial anode suitable for water tanks and water heaters with consumption display, which is also extremely robust due to the lack of a displaceable display element and therefore also From this point of view, it is particularly well suited for a less individualized mass installation in serial containers ex works.

In its practical and basic design, the sacrificial anode according to the invention with consumption indicator consists of an anode screw connection, preferably injection molded plastic, which is used to fasten the sacrificial anode in a container bore into which - the anode screw connection penetrates in the axial direction and at both ends this outstanding - the one, designed as a contact sleeve contact part is injected, as well as in a screw bush made exclusively of plastic, into which the other contact part designed as a contact pin is injected. The contact sleeve has an external thread at its one end facing the anode rod for the anode rod to be screwed on, and an internal thread at its other end for screwing in the screw bushing carrying the contact pin. In the screwed-in state, the contact pin protruding into the contact sleeve is from the contact sleeve through the plastic screw bushing electrically isolated and separated in its exposed area within the contact sleeve by a cylindrical air gap from the contact sleeve. The contact pin either extends to the end of the contact sleeve (at low tank pressure) or (with uncut iron core of the anode bar and higher tank pressure) so that there is a distance between the contact pin and the anode bar when the anode bar is screwed on. For the connection of a stationary signaling device, the contact pin can carry a thread and a nut for attaching a cable lug on its outwardly projecting short end, whereas another cable lug for connecting the contact sleeve to the screw socket of the contact pin is attached to the contact sleeve.

If the contact parts are designed for the connection of a manual device only as required, the cable lugs are eliminated. To push the one device contact, the end of the contact pin is flat or lenticular and the diameter of the contact sleeve is larger than the diameter of the screw socket, so that the other, approximately sleeve-shaped device contact can be placed over the screw socket until it comes into metallic contact with the contact sleeve. An equally good need-based connection of the manual device is achieved with the same contact means if - as above - a cable lug is screwed between the screw socket and the threaded sleeve for establishing an electrically conductive connection between the metallic unit contact sleeve-anode rod and the container wall, since the sleeve-shaped device contact when Push the manual device against this contact to the contact sleeve.

The anode rod has on its one end face, in a manner known per se, a sack-shaped threaded hole into which the free end of the iron core of the anode rod projects. According to the invention, a circular groove is drawn on the anode end face around the blind bore, which carries an O-ring as a seal between the anode rod and the anode screw connection. Equipped in this way, both the anode rod and the anode screw connection can be easily and simply sealed and reliably sealed against pressurized container medium, connected to one another, and the anode rod can be replaced easily and simply by a new one after its use, without having to unscrew the sacrificial anode from the container as a whole , and, if at the same time this can be connected to the cleaning of the container after loosening a front cover of the container. In addition, the screw connection between the anode rod and the anode screw connection offers the economically prime advantage that after the anode rod has been used up, the anode screw connection and signal or contact transmitter no longer need to be thrown away, as was previously the case. Together with the extremely inexpensive manufacturability of the anode screw connection using the injection molding process, preferably plastic injection molding, while at the same time injecting the contact parts, this results in a sacrificial anode product with consumption display of high cost-effectiveness in manufacture, assembly and maintenance, compared to the previous manufacturing method by machining and manual assembly still against the destruction of material and production values acc. the “throw-away method”.

In order to obtain a metallic connection between the anode rod and the container wall, which is required for the function of the cathodic corrosion protection, and which is produced in conventional anodes by their metallic anode screw connection, the contact sleeve is - as mentioned above - connected to the container via a metallic line, the attachment of the Line on the container can be done by means of a permanent magnet. This device, which is required because of the plastic anode screw connection, can be used for the control method specified in the "state of the art" by interposing an electrical measuring device, since only the line on the contact sleeve needs to be disconnected for this, and once the progress of consumption has been reached of the anodic material and not just the final consumption.

From the practical, basic design of the sacrificial anode according to the invention with consumption indicator, there are several application requirements for the different types of container and anode screw connection, two of which, among others, contain the solution of the further object according to the invention to be able to mount the sacrificial anode with consumption indicator and at least one heat sensor together in one and the same container bore.

According to this, in a first embodiment, the anode screw connection consisting of a molded part, preferably a plastic molded part with an injected contact sleeve, is a screw nut, preferably a hexagon nut, with a threaded attachment, so that a sacrificial anode according to the invention which is equipped in this way can be screwed into a threaded sleeve which is customary on containers. Depending on the design of the connection contacts, the anode consumption can be checked by a fixedly connected signal device or by a manual device. The metallic connection between the anode rod or contact sleeve and the container is established here by a metallic line.

In a second embodiment, such containers are taken into account which are provided with a simple through hole of smaller diameter in the container wall for the attachment of a sacrificial anode. For this purpose, the contact sleeve is - in a similar manner to the anode screw connection - in a disk-shaped Injection molded plastic stopper, in this case with an externally threaded contact connection end from the inside of the container through the through hole of the container and screwed from the outside with a threaded nut along with the usual locking and sealing washers, the screw socket with the contact pin is already screwed to the contact sleeve , if it has a smaller diameter than the contact sleeve, or is screwed onto the contact sleeve by means of its contact sleeve on the container only after the sacrificial anode has been fastened, if it has a larger diameter than the contact sleeve. Depending on the design of the connection contacts, the anode consumption can be controlled by a fixedly connected signal device or by a manual device. Since the contact sleeve and thus the anode rod is already metallically connected to the container by the metallic fastening screw connection, a special line connection required for producing such a metallic connection is omitted in the other embodiments.

In a third embodiment, the sacrificial anode according to the invention with consumption indicator is basically designed like the first embodiment, but with a larger outside diameter of the anode screw connection and with the addition that at least one immersion sleeve for receiving a heat sensor is now also injected into the body of the anode screw connection parallel to the contact sleeve is, which corresponds approximately to the length of the anode screw connection and is formed at its end facing the interior of the container for a subsequent, also tubular extension. This configuration can preferably consist of an external thread at the end of the immersion sleeve and the like or a ring-shaped separating notch. for easier removal of the closed end face of the immersion sleeve, after which the tubular extension is screwed onto the immersion sleeve.

However, an extension can also be achieved by means of a plug connection. Depending on the design of the connection contacts, one or the other type of control mentioned in the first and second embodiment is also considered here, as is the metallic line connection between the contact sleeve or anode rod and the container wall according to. the first embodiment.

In a fourth embodiment, which essentially corresponds to the third embodiment with at least one injected and extendable immersion sleeve (and also to the first embodiment if an immersion sleeve is not injected), instead of an anode screw connection, a plastic end face cover of a container is the carrier of at least one injected one Immersion sleeve and / or the contact sleeve of the sacrificial anode, so that the immersion sleeve and sacrificial anode or only the sacrificial anode are installed in the container without a special mounting on the container if the end face cover is placed on the container and screwed to it. Depending on the design of the connection contacts, one or the other type of control mentioned in the first and second embodiment is also considered here, as is the metallic line connection between the contact sleeve or anode rod and the metallic part of the container. the first embodiment.

According to the fourth embodiment, the introduction of a container bore and the welding of a threaded sleeve into it for the assembly of the sacrificial anode and a further container bore together with welding work for the arrangement of the immersion sleeve and according to. the third embodiment saves the last-mentioned container processing.

• Fig. 1 die Opferanode mit Verbrauchsanzeige in ihrer praktikablen grundsätzlichen Ausbildung sowie gem. ihrer ersten Ausführungsform, in einem Mittellängsschnitt sowie mit Anschlüssen für eine ortsfeste 24-Volt-Signaleinrichtung und einem Anschluss für die metallische Leitungsverbindung mit dem Behälter,
• Fig. 2 eine Draufsicht auf die an der Behälteraussenseite sichtbare Stirnseite der Opferanode gem. Fig. 1,
• Fig. 3 die Opferanode hinsichtlich Kontakthülse und -stift wie Fig. 1, jedoch in einer dritten Ausführungsform mit zusätzlich mindestens einer eingespritzten Tauchhülse sowie mit Anschlüssen für ein manuelles Kontrollgerät und einem Anschluss für die metallische Leitungsverbindung mit dem Behälter, z.B. über einen Permanentmagneten,
• Fig. 4 eine Draufsicht auf die an der Behälteraussenseite sichtbare Stirnseite der Opferanode mit zwei in die Behälterverschraubung eingespritzten Tauchhülsen gem. Fig. 3,
• Fig. 5 die Opferanode hinsichtlich Kontakthülse und -stift wie Fig. 1, jedoch in ihrer zweiten Ausführungsform mit einem scheibenförmigen Anschlagteil aus Kunststoff anstelle einer Anodenverschraubung, zur Befestigung mittels einer Schraubmutter in einer einfachen Behälterbohrung und bei hiermit gleichzeitig erfolgender metallischer Verbindung von Kontakthülse bzw. Anodenstab und Behälterwand, sowie mit Anschluss einer 24-Volt-Signaleinrichtung,
• Fig.6 das mit einer Gewindebohrung, einer Schutzkappe und einem Dichtungsring (0-Ring) versehene, teils im Mittellängsschnitt dargestellte Ende des gem. Fig. 1 auf die Kontakthülse aufschraubbaren Anodenstabes, in einer Einzeldarstellung,
• Fig. 7 eine Draufsicht auf die an der Behälteraussenseite sichtbare Stirnseite der Opferanode gem. Fig. 5,
• Fig. 8 die Opferanode hinsichtlich Kontakthülse und -stift wie Fig. 1 und hinsichtlich Tauchhülse wie Fig. 3, jedoch in ihrer vierten Ausführungsform als Behälter-Stirnseitendeckel aus Kunststoff und eingespritzter Kontakthülse und mindestens einer eingespritzten Tauchhülse, bei ausschnittsweiser Darstellung des Stirnseitendekkels sowie mit Anschluss für eine ortsfeste 24-Volt-Signaleinrichtung und einem Anschluss für die metallische Leitungsverbindung mit dem Behälter- und
• Fig. 9 eine Draufsicht in ausschnittsweiser Darstellung auf die nach der Verschraubung des Behälter-Stirnseitendeckels mit dem Behälter sichtbare Deckelseite gem. Fig. 8.

In the drawings sheet I and II, the invention is shown for example. They show

• Fig. 1, the sacrificial anode with consumption display in its practical basic training and gem. its first embodiment, in a central longitudinal section and with connections for a stationary 24 volt signal device and a connection for the metallic line connection with the container,
• Fig. 2 is a plan view of the visible on the outside of the container front of the sacrificial anode acc. Fig. 1,
• 3 shows the sacrificial anode with regard to the contact sleeve and pin as in FIG. 1, but in a third embodiment with at least one injected immersion sleeve and with connections for a manual control device and a connection for the metallic line connection to the container, for example via a permanent magnet,
• Fig. 4 is a plan view of the face of the sacrificial anode visible on the outside of the container with two immersion sleeves injected into the container screw connection according to FIG. Fig. 3
• 5 shows the sacrificial anode with regard to the contact sleeve and pin as in FIG. 1, but in its second embodiment with a disk-shaped stop part made of plastic instead of an anode screw connection, for fastening by means of a screw nut in a simple container bore and with the metal connection of the contact sleeve or Anode rod and container wall, as well as with connection of a 24 volt signal device,
• 6 the end provided with a threaded bore, a protective cap and a sealing ring (0-ring), partially shown in the central longitudinal section of the 1 anode rod screwable onto the contact sleeve, in a single representation,
• Fig. 7 is a plan view of the visible on the outside of the container front of the sacrificial anode acc. Fig. 5,
• 8 shows the sacrificial anode with regard to the contact sleeve and pin as in FIG. 1 and with regard to the immersion sleeve 3, but in its fourth embodiment as a container end cover made of plastic and an injected contact sleeve and at least one injected immersion sleeve, with a partial representation of the end cover and with a connection for a fixed 24-volt signal device and a connection for the metallic line connection with the Container and
• Fig. 9 is a plan view in a fragmentary representation of the visible after the screwing of the container front cover to the cover side according to. Fig. 8.

The four types according to Fig. 1 to 5 and Fig. To 9 can either with a fixed signal device, such as consisting of the fixed cable lug connections 7 and 8, the display means 9 and a e.g. 24 volt power source (e.g. the secondary side of a mains transformer), according to Fig. 1, 5 and 7 may be equipped or only with contact connections 4a and 6 or 8a in Fig. For pushing a manual control device. 1, 3 and 8, the container 3 and the contact sleeve 6 must be connected to the anode rod 10 by a metallic line 8a, the connection to a container 3 being able to consist of a permanent magnet.

The design of the contact parts in all embodiments consists of a contact sleeve 6 injected into the anode screw connection 1, 1a or into the disk-shaped stop part 2 or into the front cover 17 of a container, and from a contact pin 4 which is axially penetrated by a screw bushing 5. is held and arranged by screwing the screw bushing 5 into a threaded bore of the contact sleeve 6 while maintaining a cylindrical air gap to the inner wall of the contact sleeve 6 within the contact sleeve 6. The injection-molded parts 1, 1, 2 and 17 mentioned are preferably made of plastic and the screw bushing 5 is basically made of plastic or another insulating material because of its required electrical insulating effect between contact pin 4 and contact sleeve 6.

For the detachable connection of the anode rod 10 to the anode screw connection 1, 1a and the other supports 2 and 17 of the contact sleeve 6, the contact sleeve 6 is provided with an external screw thread at its end facing the interior of the container, and the end face of the anode rod 10 facing the contact sleeve 6 is provided with a corresponding threaded blind hole and with a self-sealing so-called O-ring 12 lying in an annular groove around the threaded pocket bore. This end of the anode rod 10 is also equipped in a known manner with a protective cap 11 which prevents the premature use of the anodic material in this area. The length of the threaded sleeve 6 depends on the length of the injection-molded part 1, 1a, 2 or 17 carrying it. The length of the signal pin 4, however, depends on the pressure size of the container medium in question and should run to the end of the contact sleeve 6 at a relatively low pressure , since the air column located in the common interior of the contact sleeve 6 and the blind bore of the anode rod 10 is compressed in this case correspondingly slightly less than at higher pressure by the ingress of the anode rod 10 through its blind bore when the anode rod 10 is consumed, but the penetrating water only through simultaneous air compression can reach the two contact parts 4 and 6, an electrically conductive connection being established by the water bridge. In the course of the contact pin 4 to the end of the contact sleeve 6 - as stated above - it is necessary to shorten the iron core 10a of the anode rod 10 so that a distance visible in FIG. 1 is maintained between the contact pin 4 and the iron core 10a.

In a further use, this distance is used to insert a suitably tableted salt, e.g. NaCl, if the water entering after consumption of the anode rod 10 is to be increased in its electrical conductivity, which takes place after the salt has been dissolved in the water. Since the cylindrical air gap between the contact sleeve 6 and the contact pin 4 is in a certain ratio to the conductance of normal water at a certain test voltage, the water bridge as an electrical cable bridge would not be sufficient if the air gap was adjusted if the voltage was reduced or a different one at the place of use predetermined voltage is found.

In this case, the conductivity of the water can be increased as described above. If the two components mentioned are dimensioned correctly, an admixture of this type is not necessary. However, it can also be provided in principle by inserting the tableted salt before screwing on the anode rod 10, if one wishes to be certain of multiple security for each case.

The embodiment acc. FIGS. 4 and 4 are additionally equipped with at least one immersion sleeve 13 for receiving a heat sensor, for which purpose the anode screw connection 1a has a correspondingly larger diameter than the basically identical design according to FIG. Fig. 1, which, like the training acc. Fig. 3, can be screwed into a threaded sleeve of a container 3, as shown in Fig. 1, for example. For the sake of clarity, the immersion sleeve 13 is shown in a length corresponding approximately to the anode screw connection 1a, also because this should be the length that is favorable for production for the injection process. In practical training, there is a screw thread at the closed end of the immersion sleeve 13 and preferably an annular groove or the like running around. as a preparation to be able to separate the bottom of the immersion sleeve more easily if necessary - for example sawing off - or to be able to remove the immersion sleeve 13 is open from the outset at this end. For extension, extension tubes of different lengths can be provided, one end of which is closed and the other end of which has an internal thread, as a result of which the extension tube and immersion sleeve 13 can be easily connected to one another.

The embodiment acc. 8 and 9, also a combination of sacrificial anode and immersion sleeve 13, corresponds essentially to the embodiment according to. FIGS. 4 and 4. In contrast, the two control devices are, however, injected into a front cover 17 of a container when it is manufactured in a plastic injection molding process and together form a structural unit. Contact devices 4, 5 and 6 of the anode rod 10 and immersion sleeve 13 are in this case mounted in a base-like cover reinforcement 17b of the end cover 17. After screwing an anode rod 10 onto the contact sleeve 6, screwing corresponding extension tubes onto the immersion sleeve 13 and inserting the heat sensor and screwing the front cover 17 by means of screw holes 17a on a container, both control devices are simultaneously introduced into the container without separate construction measures.

The embodiment acc. Fig. 5, which is attached to a container 3 only at a push-through hole of the container and by screwing using a screw nut 15 together with the usual sealing and locking washers, requires as an injection molded part, into which the contact sleeve 6 is injected, only an annular stop part 2 and an additional screw thread for the screw nut 15 on the outwardly white end of the contact sleeve 6. As shown, this embodiment is suitable for a fixed signal device.

In another training for carrying out the control by a manual device or the like with their slip contacts. against the pin contact 4, preferably in its flat or lens form 4a, and must be pressed against the sleeve contact 6, the screw bushing 5 - in contrast to the drawing - has a smaller diameter than the contact sleeve 6 so that contact with the contact sleeve 6 is possible at which slipping on the approximately sleeve-shaped contact of the device, the other contact arranged inside the approximately sleeve-shaped contact touches the contact pin 4 or its contact surface 4a.

Claims (10)

1. Sacrificial anode with consumption indicating instrument for water tanks and for electric water heaters, characterized by the fact that the fastener of the sacrificial anode shows at the one vessel wall two contact pieces as a kind of electrical conductors, being isolated from each other and penetrating the fastener in an axial direction - this arrangement is made in a way that the ends of the conductors which point to the inside of the vessel, are sealed against the liquid media within the vessel as also against penetration of the liquid media, a result which will be obtained by means of the anode rod which is attached to this front side of the fastener as also characterized by the fact that at their other ends which are accessible at the opposite front side of the fastener and which are to be found with this part of the fastener on the outside of the vessel, a signaling device is connected electrically and which operates in the way of visual and/or acoustic means of communication and that the both contact pieces which penetrate the fastener of the sacrificial anode, activate the signaling device in case of short circuit due to liquid media of the vessel which did penetrate after the sealing was neutralized.

2. Sacrificial anode as claimed in claim 1, wherein a fastener which is shaped like an anode screwing (1) and a contact bush (6) forming the one contact piece and penetrating the anode screwing (1) in an axial direction, supported by a screw socket (5) which consists of insulating material and by means of the screw socket (5) will be screwed into an internal thread of the contact bush (6) which forms by means of the contact pin (4) the other contact piece in a way that within the contact bush (6) preserving a cylindrical air separation to the inside wall of the contact bush (6) and together with the contact bush (6), it extends to the inside of the vessel (3) just as far as it preserves an air separation to an anode rod (10) which has to be screwed on here, respectively to its metal core (10a) and by the fact that on a screw thread of the contact bush (6) respectively at its end which points to the inside of the vessel, an anode rod (10) is screwed on to the front side and which is provided with a thread pocket bore, as well as by the fact that at the front side of the anode and around the thread pocket bore, a groove with an inserted O-ring (12) is provided as a sealing in a way that hereby a sealing of the contact pin (4) and of the contact bush (6) will exist against the liquid media of the vessel and by the fact that the other ends of the contact pin (4) and of the contact bush (6) which are accessible from the outside of a vessel (3) are equipped with connecting devises (7, 8) for a stationary signaling device (9) or with connecting devices (4a, 8a) for a manual signaling device.

3. Sacrificial anode as claimed in claim 1 and 2, wherein the contactor (4, 5, 6) which is composed of the contact bush (6) and the contact pin (4) with the screw socket (5), is supported by means of a disk-like arresting device (2) penetrating this one and that the contact bush (6) owns an outside screw thread with a screwed nut (15) at is end which is accessible from the outside of a vessel (3).

4. Sacrificial anode as claimed in claim 1 and 2, whereat within the anode screwing (1a) in parallel to the contact bush (6), at least one immersion shell (13) the end of which being closed, is arranged for the incorporation of a thermostat in a way that the open end of the immersion shell (13) is to be found on the front side of the anode screwing which is accessible from the outside of a vessel (3).

5. Sacrificial anode as claimed in claim 4, characterized by an immersion shell (13) being open at both ends, as well as by an extension tube which is attached to the end of the immersion shell (13) which points to the inside of a vessel, the extension tube being closed at its opposite end, the arrangement being made in a way that the immersion shell (13) and the extension tube proceed on the same vanishing line.

6. Sacrificial anode as claimed in claims 4 and 5, whereat the arrangement of the contactor (4, 5, 6) and of at least one immersion shell (13) has been made at a front side cover (17) of a vessel (3) within a socket-like cover reinforcement (17b) by ceasing an anode screwing (1a) in a way that at a front side cover (17) which is screwed with a vessel (3), the contactor (4, 5, 6) together with the anode rod (10) which has to be screwed on to the contact bush (6), as well as the immersion shell (13), extend into the vessel (3) and in a way that the front side cover (17) with the contactor (4, 5, 6) and the immersion shell (13) form a part in one piece only.

7. Sacrificial anode as claimed in claims 2, 4, 6, wherein the anode screwing (2, 2a) and the front side cover (17) consist of synthetics.

8. Sacrificial anode as claimed in claims 2, 4, 6, wherein the anode screwing (2, 2a) and the front side cover (17) consist of metal.

9. Sacrificial anode as claimed in claims 2, 4, 6, characterized by a metallic junction of paths (8a) between contact bush (6) and vessel (3), as also by a connection of the junction of paths (8a) to the vessel (3) by means of a permanent magnet (16).

10. Sacrificial anode as claimed in claims 2, 3, 4, 6, whereat pelleted of salt, an inserted part within a limited space will be formed in a fitting way at the opposite front sides of the contact pin (4) and the metal core (10a) of the anode rod (10).

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