US 814951 A
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PATENTED MAR. 13V, 1906. R. A. FESSENDEN. y
APPLICATION FILED nBc.14,-19o4.
2 SHEETS-SHEETl No. 814,951. PATENTBD MAR. 13, 1906. R. A. FESSENDBN'. CAPACITY.
APPLICATION FILED 920.14, 1904.
' z snmsnsma LIL , and the dielectric.
UNTTED sTATns PATENT OFFICE.
REGINALD A. FESSENDENOF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO THE NATIONAL ELEC'IIVRtlI.) SIGNALING'COMPANY, OF PITTSBURG, PENNSYLVANIA, A CORPORATION OF NEW JERSEY.
To all whom, it may concern- Be it known that I, ItEeiNALD A. Brassart-y nnN, a citizen of the United States, and a resident of FVaShingtOn, District of Columbia, have invented certain new and useful Impiroveinents in Capacities, of which the following` is a specification.
The invention herein described relates to improvements in condensers, especially condensers for use with alternating currents of high frequencies, and still more especially to condcnsers for use in wireless telegra h The invention is hereinafter more gill y described and claimed.
part ol this s ecification, Fi .es 1, 4, and 6 show views o condensers lem od 'ng my improvement. Figs. 25, and 7 s w sections of the same, and Fig. 3 shows an arrangement of circuits for use in connection with my invention.
in the accompanyingdrayxigs, forming a Ileretofore there has been great difficulty have found that t 1e use of glass condensers as ordinarily constructed is objectionable on account ol the presence of very heavy los/ses and objectionable heating.
In applying comparatlvel7 large metallic sheets to the surface of a die ectric it is practically impossible to prevent the formation of minute pockets between. the metallic sheets These pockets contain l'luids which cannot be removed and the prescin .c of which give rise to large losses.
I have' discovered that one of the chief dificulties is due to the irregular or non-conti nous contact between the metalliccoatins ol the condenser and the dielectric material het woon the coatings and have given amathematinal explanation of this effect 'in al paper specication of Letters` Application led December 14, 1.904.
,Non insulation' and conduction.
Oil condensers have been,
Glass has:4 been very genera-ll used for this work; but I' Patented march 13, 1906.
sei-a1 rol/,naaste a. A' (American jnsti'tute Electricm Engineers, 1898.)
As the result of numerous experiments I have foundvthatthis difficulty can be over come byr making the metallic coatings in such manner that they are uonintegralfie., are formed of a. large; number of small areas' arran ed in such relationto leach other that whi e currents can freely pass from one area to the next there will be openings of spaces between adjacent areas permitting the removal or escape of' fluids from'v between the metallic sheets 'and the dielectric. By reason of the small extent of the areas the'formation of continuous 'contact between the areas and the surface of. the dielectric can be leasil andsurely attained. #As the areas are yevaporation or extraction of the solvents gases whichwould otherwise remain between the. metallic coating andthe dielectric.) As
preferably of the same character as the dielectric lyingbetween the coatings.
In Fig. 1, 1 is a plate which :may be of mica, and 2re resents small areas of tin-foil ap lied so as to e in continuous contact.. Acondhctf ing-plate from one area to another is formed by causing adjacent areas to overlap to a certain electric opemngs or 'spaces should be left for the escape or removal of iiuids, &c. p Fig. 2 is a sectional View of the same, showing the mica plate 1, the tin-foil coating 2, and a of'the tin-foil coatings, so as to prevent ldischarges from the edges of the coatings.
*In the construction shown in Figs. 4 and 5 a large sheet of metal, as tin-foil, is divided up into small connected areas 4, forming holes or openin s 5 through the sheet, sai'd holes or openings eing su'fiiciently numerous and so dlstributed as to afford am le o portuni'ty for the escape of or removall) of fluids, &c., from between the metallic coating and the surfaceof the dielectric.
t3 shows vstill another form in which a plate metallic coating consists of areas formed by ilattening a sheet of wirefgauze, as
smal the openings or s aces between, adjafl cent areas 'are numerous, permlttmg th-free a further improvement I have found it advantageous to cover-,the edges of the coatin s by an additional layer of insulating materia whichA may be used in the cement or of air or extent. In applying these areas to the diprotecting layer of mica 3 covering the'edges A hi' passing; it lictwccn rolls, and causingr it to present :in almost pcriectliV continuous sur t'acc, with` however, sinall intcrsticcs to pciinit olI t liccrapornt ion` removal, or renewal by a cucunin-pump oll ohjcctionzihlc fluids or gases which might otherwise exist between the coatings and the dielectric.
its illustratingl 'the improved results ohtiiiiicd ln' this no\f'clnitr1.thod of construction tiro contlciisersy were taken. hoth having similar plates nl' iniczi, but the metallic coatings ol' one formed ot"t\\'osiiif1lc pieces of' tinl'oil, while the metallic coatings ol the other nere lornicd of :i nunihcr ol' small arcas zii'- ranucd :is descrilied. )oth condcnscis were 'tested with thc same alternating@current voltage, and whereas tht` one whose coatings were lornicd ol large pieces oli tin-foil hecairie rcry hot and hrolic down in a l'cw niinutcs :it twelve thousand tirc hundred volts, the onc'whosc coatings irc-rc lornicd ol a iiuinhcr of snnill :irons ol' tin-l'oil in continuous contact n'ith thc diclcciri :it the end olI one honi' liz-o not onli not hrolicn down, hut was so co/l that n piccc ol' parallin placed upon azi not sol'tcncd.
l do not liinit` mysclf to ainv particnlin liind oi dielectric or to an)Y particular hind olI rnct'tillic coatings, as l'hzivc lonnd this niothod :iniilicahlc to man): types olI condcnscrs. lnstend of mica, hard ruhhcr or even in soine cascsglass ina)v hc' used7 and the coatings may l .i applied directly, as in the caseol' gold-letti", or muy he applied with suitalile cement-as, lor example. a solution of sliellat' .tir may he Yulctinizcd in position.
The solvent and gases inniv he removed hy haliincr under heat with or without pressure or h): a vacuum with or without pressure. ln all casos, however, the conducting-cout ings should hc so arranged as to malte good continuous contact with thc dielectric and to avoid thc retention or entrance o'l` objection'- ahlc fluid` oi gases hetn'ccii the metallic coatings :ind thc dielectric.
cnihodyinler the invention herein described. H is n sending-conductorgrounded at 9. l() is a condenser oll the forni herein described. l1 is it spark-gap. 12 is a source of alternating meest current; 113, a signal-key; 14.-, a translioriner. (hi depression ol` the hey 13 the condeneer i() is charged and discharged across the gap, thcrch)Y emittingr the waves which are reccivcd upon the receivingg-conductor 1.5, which is operatively connected to the receiver ii oi the type descrihed in Unit/ed States VPatent i\`o 706,735, said 'recenterbeing;I arranged in a closed tuned circuit which is preferably tuned to the saine frequency as the receiving-conductor 15, sending-conductor i, and the local Sending-circuit, containing` the condenser t() sind snarhrganli. lo is an indicating instrument, and i7 is a local battery.
i claim herein :is my intention--H l. condenser' having in combination a dielectric angl metallic coatings coin nosed of a nuinher of small areas electrically conincted.
s dielectric and metallic coatings in continuous contact with the dielectric exceptat such'portions as the areas contact with each other,
2S. A condenser haring in combination a" dielectric and metallic coatings com iosec'i oi a nuniher of small areas electrically,T corinectcd sind in continuous Contact with the dielectric.
4f. A condenser having in conihination a solid dielectric and metallic coatings in continuoue contact with the dielectric and having their edges protected by solid insulatingr material.
A condenser having in combination a dielectric and non-integral metallic coatings in elt'fctricz'il contact,
A condenser having in coinhination ti dielectric and nim-integral metallic coatings in electrical contact with one another and in continuous Contact except atl Such portions 1 as the 'arcas contact with each other with the dielectric.
Signed at iVashington, District oi (Johnnbia, this 14th day ol' December, A. D. 1904. l* ig. I shows sendingr and receiving stations RE NAL-D A. FESSEIIDRN.
Tiionis P. Bnowx.
Jessie E. BENT.
A condenser having in combination a