| Scraper for a device for breaking bath crust in an electrolytic cell intended for aluminium production -> Monitor Keywords |
|
|
  Scraper for a device for breaking bath crust in an electrolytic cell intended for aluminium productionUSPTO Application #: 20070246347Title: Scraper for a device for breaking bath crust in an electrolytic cell intended for aluminium production Abstract: The invention relates to a scraper (40) for a crust breaking member (33) such as a crust breaker, useable to form an opening in an alumina and solidified bath crust in a fused bath electrolytic cell by a back and forth motion of the said member along a translation axis T. The scraper (40) according to the invention comprises a plurality of fingers (42) arranged around a reference axis S intended to coincide with the said translation axis T during use, so as to leave a space (44) between the fingers and the crust breaking member, and each finger (42) comprises at least one scraping member (43) projecting towards the crust breaking member (33). The scraper according to the invention is used to prevent the formation of an envelope on the surface of the crust-breaking member that can block the member in the scraper. (end of abstract) Agent: Banner & Witcoff, Ltd. - Chicago, IL, US Inventor: Bernard Bourges USPTO Applicaton #: 20070246347 - Class: 204194000 (USPTO) Related Patent Categories: Chemistry: Electrical And Wave Energy, Apparatus, Electrolytic The Patent Description & Claims data below is from USPTO Patent Application 20070246347. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001] The invention relates to electrolytic cell equipment intended for the production of aluminium by fused bath electrolysis according to the Hall-Heroult process. In particular, it relates to devices for breaking solid bath crusts in the said electrolytic cells. STATE OF THE ART [0002] Operation of an aluminium production cell by fused bath electrolysis of alumina dissolved in a bath based on cryolite causes a permanent change to the bath composition. Firstly, the alumina is consumed by electrolysis reactions, and secondly the bath quantity and composition are progressively modified by secondary mechanisms such as absorption of cryolite constituents by the walls of the cell or the decomposition of fluoride constituents by anode effects. Consequently, it is important to add alumina and bath compounds such as cryolite (Na.sub.3AIF.sub.6) or aluminium fluoride (AIF.sub.3) regularly to stabilise cell operation parameters. [0003] The alumina and bath compounds are usually added into the bath in the form of a powder. Electrolytic cells are usually equipped with one or several powder distributors associated with a device for breaking the alumina and solidified electrolyte crust that covers the bath surface during normal operation, so that the powder material can be added into the electrolyte bath. The crust breaking device usually comprises a jack and a crust breaking member called a "crust breaker", "plunger" or "crust breaker chisel" fixed to the end of the jack rod. The crust breaker, usually placed vertically, is lowered by activation of the jack and breaks the alumina and solidified bath crust. The crust breaking devices usually also comprise a scraper to eliminate solidified bath depositions that tend to form on crust breakers. [0004] French patents FR 2 455 093, FR 2 487 386 (corresponding to American patent U.S. Pat. No. 4,431,491) and FR 2 527 647 (corresponding to American patent U.S. Pat. No. 4,437,964) in the name of Aluminium Pechiney describe alumina point feeding devices to an electrolytic cell designed for production of aluminium. These devices, known as "crust breakers--feeders" when they are combined, include alumina supply means and a crust breaking device for breaking the alumina and solidified bath crust. The crust breaking device is provided with a scraper that encircles the crust breaker tightly. [0005] However, the solidified bath sometimes forms an envelope on the surface of the crust-breaking member that can block the member in the scraper. The Applicant attempted to find means of avoiding this disadvantage. DESCRIPTION OF THE INVENTION [0006] An object of the invention is a scraper for a crust breaking member (such as a crust breaker, a plunger or a crust breaker chisel) useable to form an opening in an alumina and solidified bath crust in a fused bath electrolytic cell by a back and forth motion of the crust breaking member along a translation axis T. [0007] The scraper according to the invention comprises at least three fingers arranged around a reference axis S that will coincide with the said translation axis T during use so as to form a space called a "clearance" between the fingers and the crust breaking member, and each finger comprises at least one scraping member projecting towards the crust breaking member. [0008] The Applicant had the idea of separating the scraper into a set of scraping members separated from each other, reducing the contact area with the scraper and arranging the scraping members on a plurality of fingers at an angle spacing from each other. This approach prevents the crust breaking member from getting blocked by limiting the force necessary to bring it free if there is an accumulation of bath crust between the scraping members and the crust breaking member. The applicant also had the idea of moving the fingers well away from the crust breaking member of the crust breaking device, so as to encourage the accumulation of bath crust debris above the scraping members, rather than their insertion between the jacket and the crust breaking member. The accumulated debris can then easily be evacuated through the space formed by the separation between the scraper fingers. [0009] The invention is particularly suitable for the electrolytic cells to be used for aluminium production. [0010] Another object of the invention is a crust breaking device intended for an aluminium production cell using fused bath electrolysis and comprising a scraper according to the invention. [0011] Another object of the invention is a crust breaker - feeder for use in an aluminium production cell using fused bath electrolysis and comprising a scraper according to the invention. [0012] Another object of the invention is a crust breaking and measurement device intended for use in an aluminium production cell using fused bath electrolysis and comprising a scraper according to the invention. [0013] Another object of the invention is the use of the scraper according to the invention in an electrolytic cell intended for the production of aluminium by fused bath electrolysis. [0014] The invention is described in detail below with reference to the appended figures. [0015] FIG. 1 is a simplified diagram showing a partial inner view of a typical electrolytic cell intended for the production of aluminium by fused bath electrolysis, seen in a vertical section. [0016] FIG. 2 shows a perspective view of a preferred embodiment of the scraper according to the invention. [0017] FIG. 3 shows a side view of the scraper in FIG. 2. [0018] FIGS. 4 and 5 show sectional views of the scraper in FIG. 2, along the sectional planes indicated in FIG. 3. [0019] FIG. 6 shows a perspective view of the scraper in FIG. 2 fixed to the end of a crust breaking device. [0020] As shown in FIG. 1, an electrolytic cell (1) for aluminium production by fused bath electrolysis, in other words by molten salt electrolysis, comprises a pot (2), one or several anodes (3) (typically prebaked anodes made of a carbonaceous material), and feeding means for powder materials (20, 30), usually fixed to a superstructure (4) arranged above the pot. [0021] The electrolytic pot (2) comprises inner lining means (not shown) and a cathode assembly (5) that form a crucible inside the pot (2) that can contain the electrolytic bath and a liquid aluminium pad (6) when the cell is in operation. The anodes (3) are normally partially immersed in the liquid electrolytic bath (7) and the cells are operated so as to form an alumina and solidified bath crust (10) above the electrolytic bath. Continue reading... Full patent description for Scraper for a device for breaking bath crust in an electrolytic cell intended for aluminium production Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Scraper for a device for breaking bath crust in an electrolytic cell intended for aluminium production patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Scraper for a device for breaking bath crust in an electrolytic cell intended for aluminium production or other areas of interest. ### Previous Patent Application: Electroformed sputtering target Next Patent Application: Stabilizer with cathodic protection Industry Class: Chemistry: electrical and wave energy ### FreshPatents.com Support Thank you for viewing the Scraper for a device for breaking bath crust in an electrolytic cell intended for aluminium production patent info. IP-related news and info Results in 1.82253 seconds Other interesting Feshpatents.com categories: Electronics: Semiconductor , Audio , Illumination , Connectors , Crypto , |
||
