US2129008A - Condenser - Google Patents

Description

J. A. KATERA Sept. 6, 1938.

GONDENS ER Filed May 20. 1936 /m/ENTOR J.A. KATE/1 Tom/EV Patented Sept. 6, 1938 vf'ul'JmTED'STATES Pa'rrzlsl'r OFFICE Application May 20, 1936, Sel-lll No. y80,779

l Claim.

This invention relates toI electrical condensers and more particularly to condensers having dielectrics with conducting surfaces intimately associated thereon.

In such condensers, particularly in the case of high frequency-high potential condensers, it is desirable to avoid excessive electrical resistance in the conducting elements and to make adequate provision for heat dispersion. Also in the event that the dielectric member is made of fragile material, it is important that the dielectric member be supported so as to minimize the effect of vibration and shock.

An object, therefore, of the present invention is a condenser with a dielectric and intimately associated conducting surface thereon having improved means for conducting heat therefrom.

Another object of the invention is an improved structure whereby the dielectric member is supported in a container by members which act to lessen the possibility of damage to the unit by vibration or violent shock.

A further object of the invention is an improved method of current distribution to the intimately associated conducting surfaces on the dielectric whereby high current densities in the thin conducting surfaces are prevented.

A still further object of the invention is a high voltage-high frequency condenser which can be operated at relatively high atmospheric temperatures without deterioration of the condenser.

In accordance with the present invention, these and other objects are attained by mounting a condenser unit comprising a dielectric member having conducting coatings thereon on supporting members which contact the thin conducting surfaces over a substantial portion of their area and which resiliently support the unit and serve to conduct heat away from the unit, as well as electrical conductors therefor.

These and other objects of the invention will be made clearly understood from the accompanying drawing and detailed description, in which Fig. 1 is a view of a condenser unit mounted in F its casing; and

Fig. 2 is a View of a condenser unit associated with its terminal members before it is installed in the casing.

The condenser unit shown in Fig. 1 comprises a dielectric tube 5 having a conducting coating 6 on its inside surface and a second conducting coating 'I on its outside surface. While quartz is preferred as the dielectric material for the tube, the use of other ceramic materials, such as glass and porcelain, are contemplated by the inven- (Cl. F15-41) tion. The unit is mounted in a metal container 8 having a metal base 9 and a cylindrical insulating cover I on the opposite end thereof. This cover may be of Isolantite" or any other suitable insulating material. 'I'his insulating cover I0 5 may be soldered to the metal can at I I. A terminal Il, which is connected to the inner conducting coating 6 by means of the metal cylinder 4, extends through the insulating cover I0 and is soldered thereto at I4. The terminal I con- 10 necting the outside coating is integral with the base 9. A thin metal cylinder 4 is fitted inside the dielectric tube 5 in such a manner that it is in contact with the inner conducting coating 6 for substantially its whole area and is soldered thereto at 35. A second thin metal cylinder I6 is tted over the outside conducting coating I and is also in contact therewith and is soldered thereto at 36. I'hese cylinders, which are in contact with the respective terminals, serve to distribute current to the metal coated surfaces of the dielectric tube in such a manner as to avoid high current density in these surfaces and, therefore, prevent high energy loss and heating of the condenser. The ends I1 and I8 of the respective 25 metal cylinders extend beyond the dielectric tube and engage the extensions I9 and 20 of the terminal members I 3 and I5. Since in the preferred form these cylinders are of thin metal, they also serve to hold the dielectric tube, which is preferably very thin, resiliently in the casing. 'I'his prevents vibrations and shocks from cracking the tube. 'Ihe cylinders also serve to conduct heat from the metal coated dielectric to exposed parts of the condenser where it is dissipated.

'I'he construction of the condenser unit will be more clearly understood by referring to Fig. 2, which is a cross-sectional view of the unit without the enclosing casing. In this drawing, the dielectric tube is shown at 5 coated with a con- 40 ducting surface 6 on its inside and a conducting surface I on its outside. 'I'he thin metal cylinder 4 is fitted inside the tube in contact with the conducting surface 6 and is soldered thereto at 35. The second thin metal cylinder I6 is tted over 45 the exterior conducting coating 1 for a portion of its surface and is soldered thereto at 36. 'I'he inner metal cylinder 4 extends out of the dielectric tube as shown at I8 and the extension I9 of the terminal I3 is fitted tightly therein.' 50 Similarly the outer metal cylinder I6 extends beyond the lower end of the dielectric tube 5 as shown at I1 and the extension 20 of the integral container base 9 and terminal I 5 is fitted therein.

The base 9 contains a circular groove 2| there- 55 in l'ig. i, the circular metal thereto. As stated above. the upper end of the metal conis closed by the insulating cylinder Il.

soldered at il to the insuthe terminal Il is further held in washers I! and the nut Il. Ad ditional washers 2| cooperating with nut 2l may be to fasten electrical connections to terminal. The space Il between the cascondenser insulating compound, wax, paralin, petrolatum or chlorinated diphenyl, for example, by a vacuum process. However, in somecasesitmaybe deairabletoleave thisspace vacant. in which case the outside of the ooncentric unit may be coated with a protective coating of an insulating varnish. or the like. Buch an insulating coating will reduce corona discharge by preventing moisture from being adsorbed on the dielectric member. If the space Il is filled with insulating compound it is introdwed within the casing through an aperture made by removing screw Il from the base I. The air in the interior of the tubular unit is evacuated through the holes il and 32 in the extension II of the inner metal cylinder I. The insulating compound is. therefore, free to now into the interior of the unit through these holes. The holes I3 and Il are made in the outer metal cylinder so that there will not be an air pressure pocket within the unit when the container is evacuated. If the unit is not to be vacuum impregnated but only varnished, the holes Il, 82, 3l and Il may be omitted.

The dielectric tube may be coated with the thin eonductingcoatingsbyany suitablerxooel knowninthe art. suchassprayingehemicalprecipitation baking, etc. While various metals. or alloys'` might be used for this coating. diver been found to be very satisfactory. ity of theunitatthestageshown be adjusted by removing portions oi the outer silvercoatingasshownat ilpriortolnstalling the unit in the casing. A

Although a hollow tubular dielectric member is preferred,itis.ofcourae,obviousthatother formsofdielectriesmaybeMforexample, solid dielectrics with conducting coatings on oppositesidesthereofwhicharesupportedbyrcallient mounting members.

A particular advantage of the condenser hsving only insulating varnish over the concentric condenser unit is that there are no materials in the condenser which will deteriorate at high temperatura of the order of 100 C. It is thus possible, for example, to construct a high voltage-high frequency condenser operating at a voltage of about 2000 volts and a frequency of about 6 megacycles for operation at high atmospheric temperatures.4

what is claimed is:

In an electrical condenser mounted in a casing, a condenser unit comprising a metal coated dielectric tube. a pair oftermlnals therefor, a thin metal cylinder inside said tube and in contact therewith and another thin metal cylinder outside said tube and ln contact therewith. and means including said thin metal cylinders for re siliently mounting said unit in the casing and for making contact between the metal coatings and said terminal members.

The infl'gJmay JOSIPHAKATIR.

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