US2757136A - Method for the electrolytic polishing of metal articles - Google Patents

Description

169-45. XR 2.757. 136 SR I X fail? 31, J HEYES METHOD FOR THE ELECTROLYTIC POLISHING 0F METAL ARTICLES Filed March :51. 1953 I HIS AGENTS 2,757,135 Patented July 31, 1956 IVIETHOD FOR THE ELECTROLYTIC POLISHING OF METAL ARTICLES Josef Heyes, Dusscldorf-Obcrkassel, Germany Application March 31, 1953, Serial No. 345,939

3 Claims. (Cl. 204-1405) The invention relates to a device for the electrolytical polishing of metal articles.

The use of an electrolyte based on acetic-acid-perchloric-acid presupposes that an explosive decomposition of the mixture must be prevented by all means. A solution of one part of perchloric acid in three parts of acetic acid is not explosive whereas this is the case with a solution containing three parts of perchloric acid and one part of acetic acid.

It has been found that an explosive separation of an electrolyte of the named composition may not take place under ordinary operative conditions; it becomes only possible, if in the case of a highly heated or burning electrolyte a particularly intensive evaporation is caused which leads to steadily increasing accumulation of perchloric acid in the mixture. lf a certain concentration of perchloric acid is exceeded the residual mixture will be decomposed in an explosive manner.

It ie fhP (\hipnt nf the inventing tr IIIQIII"? a eufn nea of electrolytes consisting of acetic acid and perchloric acid. whereby any danger of-"explosion is eliminated.

Whereas an automatic interruption of the current supply at a time where the critical temperature of the electrolyte is reached, for instance, in the case of fire, will be inefiective in view of the outer thermic effects, which act upon the electrolyte, it was found that already a small admixture of water to the electrolyte eliminates in the operative rooms the inflammation of the vapors which are produced by the heat. In conformity with the above, water is added to the electrolyte consisting of acetic acid and perchloric acid as soon as a certain room temperature is exceeded. This object may be realized by connecting a tube reaching into the electrolyte to a water supply while interposing into the device a so-called melting valve or safety fuse. With the known melting valves or safety fuses the closure member consists of a low melting material. lf the melting temperature is exceeded water flows into the electrolyte and the danger of ignition is eliminated.

ln conformity with another characteristic element of the invention water may be sprayed onto the bath surface from a tube with spray openings and located above the surface of the electrolyte.

Also in this case the tube may be connected with the water supply of a heat sensitive valve or the spray openings may be closed by a low melting material. The spray tube located above the bath and the tube leading into the same may be connected to a common safety fuse.

lt has been found particularly effective to apply means which permit a quick removal of the electrolyte. With this purpose in view the container for the electrolyte or its outlet means may be provided with an easily breale able, for instance. glass closure having a striking pin with an interposed fusion strip suspended above the same.

The striking pin may be suspended to the one end of a rope conducted on rollers, whereas the other end of the rope is connected to a weighted lever. which closes a valve provided in the water supply, whe reby safety fuses are provided in the rope between the water valve and the striking pin.

It has been found advisable to additionally use a control relay which is adjusted to about 40 C. and to adjust the water supply valves to a room temperature of 60 to C.

The wall faces of the vessel containing the electrolyte are water cooled.

The installation is supported on a grate or the like in such a manner that the cooling water and eventually also the sluiced out electrolyte may be easily flown off.

The invention is by way of example illustrated in the accompanying drawings.

In the drawings Figs. 1 and 2 show longitudinal sections of the device for the electrolytical polishing of articles constructed in accordance with the invention of the outlet from the vessel containing the electrolyte, and i Fig. 3 shows a cross section of the outlet from the vessel containing the electrolyte.

The electrolyte 2 is contained in vessel 1; a thermometer 3 is provided for. measuring the temperature of the electrolyte. If a certain temperature of the electrolyte is exceeded the relay R interrupts the current supply to the electrodes (not shown).

A tube 4 which is connected with a water supply reaches into the electrolyte; a valve 5 is inserted into the water conduit.

The valve 5 is a so-called melt-valve, of which the closure element consists of a low melting metal such as Wood metal.

In addition to tube 4 a sluicing or spraying tube 6 is qr-nujdp l sl-want this Bl\lvffll\ll vt\ ris? m n n s 1 provided with a heat-dependent valve 8. In addition to valve 8 the openings 7 of the spraying tube by the closed means which melt of a certain temperature is exceeded. The tube 4 and the spraying tube 6 may be connected to one common valve.

In the modification of the invention shown in Fig. 2 the water supply tube 4 and the spraying tube 6 are operatively connected by means of a common conduit 9 with the closure valve 11 located in the water supply 10. Valve 11 is kept closed by a loaded lever 12. This lever is connected to a rope 13, which runs over rollers 14 and causes at the other end a striking pin 15. Safety fuses 16, 17 are applied to the rope.

The striking pin 15 acts upon the discharge socket 18 of the container 1 containing the electrolyte. This dis charge socket is provided with a closure 19 consisting of an easily breakable material, for instance glass. As soon as the two safety fuses 16. 17 start to melt under the influence of an increased room-temperature not only the valve 11 is opened but the striking pin 15 drops and crushes the closure means 19 of the discharge socket 18. The electrolyte which is sprayed with water and diluted may now quickly run-off from the vessel 1.

The closure 19 may be exchangeably connected with the socket 18 by means of cap unit 20, see Fig. 3.

Since certain changes may be made in the above devices and different embodiments of t. invention could be made without departing from the scope thereof. it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What I claim is:

1. In a method for the electrolytical polishing of metal articles by means of an inflammable liquid electrolyte having a low ignition point, said articles being placed in a tank containing said electrolyte. the steps of preventing the inflammation of the heated electrolyte by introducing water through a tube into the bt ttom portion of the same, automatically controlling the supply of said water upon the establishment of a certain predetermined temperature in the electrolyte and simultaneously removing the diluted electrolyte from said tank.

2. In a method for the electrolytical polishing of metal articles by means of an easily inflammable liquid electrolyte having a low ignition point, said articles being placed in a tank containing said electrolyte, the steps of preventing the inflammation of the heated electrolyte by introducing water through a tube into the bottom portion of the same, automatically controlling the supply of said water upon the establishment of a certain predetermined minimum temperature in the electrolyte and simultaneously removing the water-diluted electrolyte from said tank by flowingvthe same over the upper rim of said tank.

3. In a method for the electrolytical polishing of metal articles by means of an easily inflammable liquid CliClfO lyte having a low ignition point said articles being placed in a tank containing said electrolyte, the steps of preventing the intlammation of the heated electrolyte by introducing water through a tube into the bottom portion 4 of the same, automatically controlling the supply 0 said water upon the establishment of a certain predetermined minimum temperature in the electrolyte and simultaneously removing the water-diluted electrolyte from the bottom portion of said tank by the automatically controlled opening of a tank exit.

References Cited in the file of this patent UNITED STATES PATENTS 671,240 Shuman Apr. 2, 1901 1,260,818 Schultz Mar. 26, 1918 2,532,907 Hangosky Dec. 5, 1950 FOREIGN PATENTS 205,181 Great Britain Oct. 11, 1923 980,505 France Dec. 27, 1950 OTHER REFERENCES MetalFinishing, November" 1949, pages 62-68, article by Jacquet. The safe use of perchloric acetic electropolishing baths.

Claims (1)

1. IN A METHOD FOR THE ELECTROLYTICAL POLISHING OF METAL ARTICLES BY MEANS OF AN INFLAMMABLE LIQUID ELECTROLYTE HAVING A LOW IGNITION POINT, SAID ARTICLES BEING PLACED IN A TANK CONTAINING SAID ELECTROLYTE, THE STEPS OF PREVENTING THE INILAMMATION OF THE HEATED ELECTROLYTE BY INTRODUCING WATER THROUGH A TUBE INTO THE BOTTOM PROTION OF THE SAME, AUTOMATICALLY CONTROLLING THE SUPPLY OF SAID WATER UPON THE ESTABLISHMENT OF A CERTAIN PREDETERMINED TEMPERATURE IN THE ELECTROLYTE AND SIMULTANEOUSLY REMOVING THE DILUTED ELECTROLYTE FROM SAID TANK.

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