US2157913A

US2157913A - Metallic vapor discharge device

Info

Publication number: US2157913A
Application number: US185913A
Authority: US
Inventors: Nehls Walter
Original assignee: Siemens AG
Current assignee: Siemens Schuckertwerke AG; Siemens AG
Priority date: 1937-01-22
Filing date: 1938-01-20
Publication date: 1939-05-09
Anticipated expiration: 1956-05-09

Description

ay 9, 1939. W NEHLS METALLIC VAPOR DISCHARGE DEVICE Filed Jan. 20, 1958 4 Sheets-Sheet l J', A. JM

ATTORNEY w. NEHLS 2,157,913

METALLIC VAPOR DISCHARGE DEVICE Filed Jan. 20, 1938 4 Sheets-Sheet 2 JJW ATTORNEY ay 9 W39- w. NEHLs METALLIC VAPOR DISCHARGE DEVICE Filed Jan. 20, 1938 4 Sheets-Sheet 3 INVENTOR VVG/Zei /Ve/ZIZS.

ATTORNEY L. 9, H939. W. NEHLS 2,157,913

METALLIC VAPOR DISCHARGE DEVICE Filed Jan. 20, 1938 4 Sheets-Sheet 4 f IZ 2f L? 5 z5 a WITNESSESZ INVENTOR MA waz/fer /Vezl ATTORNEY Patented May 9, 1939 UNITE STT S GFFE Walter Nehls, Berlin-Haselhorst, Germany, assignor to Siemens-Schuckertwerke Aktiengesellschaft, Berlin-Siemensstadt,

Germany, a

corporation of Germany Application January 20, 1938, Serial No. 185,913

` In Germany January 22, 1937 9 Claims.

The present invention relates to metallic vapor discharge apparatus, and more particularly to a mercury vapor discharge apparatus.

Metallic vapor discharge apparatus have already been proposed which have metal vessels in which cooling inserts are arranged in the discharge space. Thus, for instance, cooling inserts have already been proposed which have the form of cylindrical bodies. These cooling inserts are secured to the cover of the metallic discharge vessels and extend to a point in the neighborhood of the cathode surface. Such cooling inserts are fed with water which has a suflicient cooling effect. However, in the case of a water cooling the weight of the converter system is increased on the one hand by the weight of the cooling water and on the other hand by the heavy design of the vessel and of the cooling agent conduit necessary for the reception of this weight, whereas in the case of an air cooling diiculties arise, since the inner space to be cooled is very small and does not present sufficiently large surfaces which might render the air cooling effective.

According to the present invention an effective air cooling is attained in which the above-mentioned drawbacks are removed, if a cooling insert is provided for air cooling, in which the speed of the cooling air at the hottest points that is to say in the neighborhood of the cathode is greatest. To: this end, it is preferable to design the cooling insert in such a manner that its horizontal cross-section decreases towards the cathode.

The novel electric discharge apparatus presents the advantage that the water cooling is entirely dispensed with and that the vacuum is not impaired by the diffusion of hydrogen ions as this is the case when employing water cooling.

With the novel electric discharge apparatus besides the removal of the above-mentioned drawbacks the advantage is obtained that the apparatus may be operated Without a pump without causing in operation` an impairment of the vacuum. However, the pumpless operation and the particular shape of the cooling inserts bring about a considerable saving in cost and weight, which increases the efliciency of converter systems equipped with the novel electric discharge apparatus. It may be, furthermore, added that the shape of the novel cooling inserts is particularly advantageous. 'I'he metallic vapors rising from the cathode do not impinge as is the case with the known inserts upon baffling plates which deflect the metallic vapor towards the zones in which are arranged the anodes, in the (Cl. Z50-27.5)

neighborhood of which condensing metallic vapors may cause backres, short-circuits and the like. The novel electric discharge apparatus is therefore characterized by the fact that it is very reliable in operation and has a long life.

According to the present invention the Ventilator may be directly fitted to the metallic vessel itself or preferably above the same and in such a manner that the current of cooling air separates the ventilator motor from the hot metal walls.

In the accompanying drawings are shown some embodiments of the invention in diagrammatic form.

Figs. l to '7 show vertical sectional views of different types of mercury vapor apparatus with metal vessels.

The apparatus vessel 2 cooled from below by means of a ventilator i consists of iron and has substantially the form of a truncated cone 3 in whose jacket are steeply inserted the anode arms which are provided with cooling ribs 5. On the cover 6 designed in the form of a doublewalled truncated cone is arranged a second ventilator 'l communicating with the interior of the cooling insert 8.

The upper part 9 of the cooling insert B has the shape of a cylinder and the lower part l!) thereof that of a cone so that the part having the smallest cross-section lies in the neighborhood of the cathode surface. In the interior of the cooling insert 8 is arranged a guide i i similar to the jacket of the cooling insert, serving to return the cooling air drawn in by the hollow double-walled cone E. The suction inlet .l2 of the double-walled cone 6 is arranged in such a manner that the fresh air is drawn in from the zone of the anode bushings. The fresh air then flows through the hollow space arranged between the outer jacket and the inner insert il to the apex I3 of the conical portion and then through the opening lll or the holes i5 in the interior of the part il to the ventilator l. By the tapering of the cross-section of the lower portion of the cooling insert an increase in velocity of the cooling medium is attained and therefore its effectiveness is increased. In the hollow space i@ may be arranged cooling ribs il' and i8, the number of which is greater in the upper than in the lower portion and the cross-section of which decreases in the downward direction.

In the embodiment shown in Fig. 2 the current of the cooling air flows in the opposite direction. The cooling air is drawn in by the ventilator i9 and impinges upon the lower portion 2li of the cooling insert 2l and returns through the hollow space 22 to the cover through whose hollow walls 23 it reaches the outlet nozzles 24, whence it impinges directly upon the anode bushings 25. Here the current of air issuing from the nozzle 24 unites with the rising current of air indicated by the arrow 26, so that the anode bushings are intense- 1y cooled.

In the embodiment shown in Fig. 3 the current of air is drawn in from the rising current of air as indicated at 27 and is caused by the blower 28 to impinge upon the anode bushings 30 through the nozzles 29. Also in this `case ribs 33 welded to the outer wall of the cooling insert are arranged in the hollow space 3l oi the cooling insert 32.

In the embodiment shown in Fig. 4 fresh air is drawn in as indicated at 34 after the anode bushings have been cooled thereby. The air then issues from the upper part of the vessel as indicated at 35. In the embodiment shown in Fig. 5 are provided special suction conduits 35 which draw in the fresh air from the zone of the anode bushings.

In the embodiment shown in Fig. 6 are provided various cooling inserts instead of a single cooling insert whose lower portion has the shape of a cone, the cooling inserts being arranged in staggered relation to one another in the manner that the cross-section of the cooling inserts in the lower portion is considerably smaller than the cross-section in the upper portion of the vessel.

In the embodiments above-described the cap 37 of the cooling insert may under circulnstances be employed in the form of a starting or exciting electrode. To this end, the cap must be connected to a conductor and suitably insulated.

The cooling insert 8 shown in Fig. '7 has at its conical end opposite to the cathode a deflccting body lili which is inserted in the tip 3i, to which end the cooling air is supplied by the outer part IG and from which the cooling air returns through the central part H. The deflecting body 49 is so designed that the cooling air is set into a vigorous circulation as indicated at 4S and is guided along the surface of the conical deflecting body 40 to the central portion Il. The surface of the conical deflecting body 69 may be increased by the arrangement of ribs or the like. In the tube l! separating the outer air path from the inner return path H perforations or slots I5 may be provided which permit a portion of the current of air supplied to the point of the cooling body to flow directly into the return path. These holes or slots l5 have the advantage that a portion of the air preheated in the central part of the cooling body may be again directly dissipated so that the fresh air flows in a greater quantity to a lower point of the cooling body. The deecting body 40 is preferably so inserted in the point 3l' of the cooling body that it does not come into contact with the mercury vapor. However, the essential point is that it is in intimate heat contact with the point of the cooling insert.

As will be seen from the embodiments shown it is advantageous to place the ventilator directly on the metallic vessel, and preferably at the upper end thereof, in such a manner that the current of cooling air separates the ventilator motor from the hot metallic walls in order to prevent the ventilator motor from being too intensely heated, which would shorten the life of the ventilator. In the embodiment shown the ventilator is arranged at the end of the cooling insert away from the discharge space.

As will be apparent from the embodiment shown the horizontal cross-section of the cooling insert in the neighborhood of the cathode amounts only to a fraction of the horizontal cross-section of the cooling insert in the upper part of the condensation chamber. A cooling insert thus shaped has the advantage that the current of the cooling air in the lower part, i. e., in the neighborhood of the cathode is rendered very effective, since the current of the cooling air has in this case the greatest speed owing to the shape of the lower part of the cooling insert.

With the aid of the cooling insert shown in Fig. '7 a particularly effective cooling is attained directly above the cathode. In this case an intense cooling is advantageous, since heat is thereby subtracted to a great extent from the vapor rising from the cathode so that the cooling surfaces in the upper part of the vessel are not so greatly stressed. As a result of the novel arrangement according to the invention special provisions need not be made for cooling the cathode, since the greatest portion of heat occurring in the cathode fall or in the portion of the positive column lying in the immediate neighborhood of the cathode is rapidly dissipated with the aid of the novel cooling insert. The other quantities of heat are carried oi by the particular construction of the converter vessel, especially by the dat bottom and by the metallic arms arranged at the lower end. If a considerable reduction of the dimensions of the vessel is rendered possible by the particular shape of the vessel, the dimensions are reduced to a further extent by the novel cooling insert, since also the small quantities of heat occurring in the neighborhood of the cathode arc rapidly carried off by the cooling air.

What is claimed is:

1. A metal vapor arc-discharge device comprising a metallic vessel, a liquid metal cathode in the bottom of said vessel, an air cooler insert arranged in said vessel, said insert extending into proximity with said cathode, an air duct extending into said cooling insert, said duct extending in spaced relation to said cooling insert to produce a double passage. means for causing air flow through said double passage, said duct and said insert being closely spaced adjacent the end nearest the cathode to provide a restriction passage for increasing the air velocity nearest the cathode.

2. A metal vapor arc-discharge device comprising a metallic vessel, a liquid metal cathode in the bottom of said vessel, an air cooler insert arranged in said vessel, said insert extending into proximity with said cathode, an air duct extending into said cooling insert, said duct extending in spaced relation to said cooling insert to produce a double passage, means for causing air fiow through said double passage, said duct and said insert being reduced in cross section at the end adjacent the cathode for increasing the air Velocity of said end.

3. A discharge apparatus as set forth in claim 2, characterized in that the cooling insert is designed in the form of a thin cone tapering towards its lower end.

4. A vapor-electric device comprising a frustoconical container providing a condensing chamber, a vaporizable cathode in said chamber, a cooling insert extending into said container, said insert having a substantially cylindrical upper portion and a substantially conical lower portion tapering toward the lower end, an air guide extending into said cooling insert in spaced relation thereto and conforming in shape to the cooling insert and means for circulating air through said cooling insert and said guide.

5. A vapor-electric device comprising a frustoconical container providing a condensing chamber, a vaporizable cathode in said chamber, a cooling insert extending into said container, said insert having a substantially cylindrical upper portion and a substantially conical lower portion tapering toward the lower end, an air guide extending into said cooling insert in spaced relation thereto and conforming in shape to the cooling insert and means for circulating air through said cooling insert and said guide, anode arms secured to said container, anode bushings at the outer ends of Said anode `arms and means for directing the air stream from said cooling insert around said anode bushings.

6. A vapor electric device comprising a frustoconical container providing a condensing chamber, a liquid metal cathode in said container, a frusto-conical top on said container, a cooling insert depending from said top and extending into proin'mity with said cathode, that portion of the cooling insert nearest the cathode being of substantially conical shape, an air guide extending into said cooling insert, said guide conforming in shape with but spaced from the insert to provide air passages therethrough, said passages being restricted in cross section adjacent the lower end of the insert, and means for propelling air through said passages.

'7. A vapor electric device comprising a frustoconical container providing a condensing chamber, a liquid metal cathode in said container, a frusto-conical top on said container, a cooling insert depending from said top and extending into proximity with said cathode, that portion of the cooling insertnearest the cathode being of substantially conical shape, an air guide extending into said cooling insert, said guide conforming in shape with but spaced from the insert to provide air passages therethrough, said passages being restricted in cross section adjacent the lower end of the insert, means for propelling air through said passages, and means for increasing the heat dissipating area of the tip of said cooling insert.

8. A vapor electric device comprising a frustoconical container providing a condensing chamber, a liquid metal cathode in said container, a frusto-conical top on said container, a cooling insert depending fromsaid top and extending into proximity with said cathode, that portion of the cooling insert nearest the cathode being of substantially conical shape, an air guide extending into said cooling insert, said guide conforming in shape with but spaced from the insert to provide air passages therethrough, said passages being restricted in cross section adjacent the lower end of the insert, means for propelling air through said passages, and cooling ribs connected to said cooling insert in the air passage.

9. A metallic vapor discharge device comprising a frusto-conical container, a vaporizable cathode in said container, a plurality of anode arms connected to said container and making an acute angle therewith, a double walled frusto-conical top on said container having passages therein for the passage f cooling air, anode insulators at the upper ends of said anode arms, said insulators being adjacent the outer terminal of the air passages in said top, a cooling insert dependent from said top and extending into the vicinity of said cathode at least that portion of the cooling insert adjacent the cathode being substantially conical, an air guide in said insert providing air passages in said cooling insert, said passages being restricted at the end adjacent the cathode.

WALTER NEI-ILS.