US2535517A - Sealed housing for an electrical condenser and method of sealing the condenser in the housing - Google Patents

Description

Dec. 26, 1950 D. H. J. RHODES 2,535,517

SEALED HOUSING FOR AN ELECTRICAL CONDENSER AND METHOD OF SEALING THE CONDENSER IN THE HOUSING Filed May 29, 1946 N I 12 I I I i a: i /I4 i I 1 i i i .3 I {L :l5

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Patented Dec. 26, 1950 SEALED HQUSING FOR AN ELEUIBIQAL @QNEENSER AND METHOD SEALING THE CONDENSER IN THE HGIUSING Dennis Henry James Rhodes, London, England,

assignor to J, (lessor Limited, London, England, a British company Application May 29, 1946, Serial No. 672,983 In Great Britain June 2, 1945 2 Claims. 1

This invention relates to electrical condensers 0f the tubular kind in which the condenser unit itself consists of windings of paper strips and metallic foils and in which said unit is contained in a tubular casing of insulating material.

Gne of the objects of the invention is to provide an improved manner of sealing the ends of such tubular condensers against ingress of moisture, and to strengthen mechanically the connection of the lead out wires which extend from the ends.

The following description relates to the accompanying drawing, which shows an embodiment of the invention by means of axial sections, Figure 1 being an expanded view and Figure 2 a final assembly view.

The condenser unit II is of the known rolled type, having interleaved metal foils and insulating paper strips wound into a cylindrical form. One foil or set of foils constituting one electrode of the condenser projects from one end as indicated at 12; and another foil or set of foils constituting the other electrode projects from the other end as indicated at l3. The unit H is housed within a tubular casing 14, which is of insulating material and may consist of a roll of paper which has been coated or impregnated with resin or other irreversible setting substance which is capable of setting hard under heat or otherwise. An example of a suitable substance is a well known thermosetting synthetic resin of the phenolic condensation product type. The setting of this material occurs on polymerisation which is efiected by heat.

Leads to the respective electrodes of the condenser are provided by wires, which are each shaped into a fiat spiral portion 15 and an axially extending portion 16, These leads are adapted to have their fiat spiral portions forced into a firm contact with the foil ends 12 and I3, the axial portions l6 then extending outwardly from the ends of the casing 14. Fitting over the axial portion N of each lead wire is a rigid disc 17, which may also be impregnated with th same material as casing I A, and which has a central hole fitted with a metal eyelet l8. 0n assembly of the parts heat is applied to the rim of the casing I l and at the same time an axial pressure is developed thereagainst by a suitable tool whereby the rim is turned inwardly to form a bead 19 (Figure 2). With the setting or hardening of the material which is carried by the easing I 4, the head I 9 is found to afford a very strong mechanical hold against a tensile force exerted between the two lead extensions 16. At the same time a complete sealing is efiected round the periphery of the disc 11, so that any ingress of moisture to the condenser unit H by a passage between the disc 17 and the casing i4 is prevented. This sealing is aided by having the impregnant or coating on the casing ll of the same material as that of the disc ll, this material being such that an intimate bonding occurs on the application of heat and pressure during setting.

The assembly is completed by a filling 29 of solder in the hole of the eyelet I8 and round the root of the lead wire IS.

The assembled condenser may be dipped in wax or other sealing and insulating material.

I claim:

1. The method of encasing a roll-condenser within a cylindrical casing which consists in impregnating at least the end portions of said casing with a material which is heat-settable to a rigid form, inserting the condenser in said casing, closing the. ends of said casing with rigid disk elements also impregnated with heat-settable material, forming inwardly turned beads on the ends of said casing and in contact with said disks, and applying heat to said beads and said disks to rigidify said beads and to seal them to said disks.

2. A sealed condenser comprising a cylindrical condenser unit mounted within a tubular element formed of insulating material impregnated with a heat-setting material which is rendered rigid under heat, said tubular element being longer than said condenser unit, a pair of rigid disks positioned within said tubular element and bearing against opposite ends of said condenser unit, said disks embodying the same heat-settable material as said tubular element, the ends of said tubular element being in-turned to form bead elements having contact with th outer faces of said disks, and said bead elements being rigidly bonded to said disks by the heat-setting material incorporated in said bead elements and disks.

DENNIS HENRY JAMES RHODES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Num er Name Date 1,633,576 Franks June 28, 1927 2,053,334 Hetenyi Sept. 8, 1936 2,057,790 Potter Oct. 20, 1936 FOREIGN PATENTS Number Country Date 345,180 Great Britain Mar. 19, 1931 398,473 Great Britain Jan. 3, 1932 556,997 Great Britain Oct. 29, 1943

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