Bushing for electrical leads

• US 4,309,568 A
• Filed: 12/29/1977
• Issued: 01/05/1982
• Est. Priority Date: 01/21/1977
• Status: Expired due to Term

• Current Assignee: Asea Aktiebolag (ABB Limited)
• Original Assignee: Asea Aktiebolag (ABB Limited)
• Inventors: Isaksson, Sven-Erik
• Primary Examiner(s): Askin, Laramie E.
• Application Number:
  US05/865,683
• Time in Patent Office: 1,468 Days
• Field of Search: 174/151, 174/18, 174/23 R, 174/65 SS, 174/77 R, 174/152 R, 277/4, 277/102, 277/105-108, 277/110-112, 277/114, 277/123, 277/125
• US Class Current: 174/151
• CPC Class Codes: H01B 17/306 by embedding in material other than glass or ceramics

Abstract

An electrical bushing is provided to facilitate the passage of electrical conductor leads from thermocouples or the like through a pressure barrier. The bushing includes a casing and a deformable, resilient, elastic plug which is disposed in a central conductor receiving bore of the casing in surrounding relationship to the conductors. Thus, when the plug is compressed in a direction axially of the casing, the plug tends to expand laterally radially and into sealing contact with the internal surfaces of the bore and with the electrical conductors.

Claims

1. An electrical bushing to facilitate the passage of elongated conductor elements through a pressure barrier comprising:

an elongated bushing casing adapted for longitudinal insertion in an opening extending through a pressure barrier and having shoulder means thereon adapted for abutment against corresponding shoulder means in said opening to thereby establish and fix the positioning of the casing in the opening relative to the barrier, said casing having a centrally disposed bore extending longitudinally therethrough from one end thereof that is intended for placement at the high pressure side of said barrier and terminating in said casing at a point between the ends of the latter thereby presenting a bottom for the bore which normally faces toward said high pressure side of the barrier when the casing is inserted in the opening, said casing also having a plurality of individual bore holes extending longitudinally through the casing from the other end thereof that is intended for placement on the low pressure side of the barrier, through said bottom and into communication with said bore, said bore holes each being of sufficient diameter to accommodate an insulated conductor element therein;

an insulator plate disposed in said bore on said bottom and presenting an upper surface facing in the same direction as said bottom, said plate having a plurality of individual bore holes extending therethrough in a direction longitudinally of the casing from said bottom and through said surface, there being a corresponding bore hole in said plate for each of the bore holes of the casing, said corresponding bore holes of the plate and of the casing being disposed in longtiduinal alignment, said bore holes of the plate each having a first length adjacent said surface which is smaller in diameter than the remaining length thereof, each said remaining length having a diameter which is substantially the same as the diameter of the corresponding bore hole of the casing for accommodating an insulated conductor element therein, said first lengths each having a diameter suitable for accommodating an uninsulated conductor element therein; and

a deformable, resilient, elastic plug disposed in said bore on said surface of the plate, said plug being of a shape and size to sealingly contact the inner peripheral surface of said bore adjacent said surface of the plate and being adapted for having uninsulated conductor elements inserted therethrough in a manner such that the material of the plug will be in contact with the uninsulated conductor elements, whereby when said plug is forced toward said plate, the plug tends to expand laterally and into sealing contact with respect to said peripheral surface and the uninsulated conductor elements when extending through the plug.

2. A bushing as set forth in claim 1 wherein is included means for forcing said plug toward said plate.

3. An electrical bushing for facilitating the passage of multiple elongated conductor elements through a hole in a pressure barrier, the hole including a cylindrical zone with a large diameter, a cylindrical zone with a small diameter, and a conical intermediate zone therebetween, said large diameter zone communicating with the high pressure side of said barrier and the small diameter zone communicating with the low pressure side of said barrier, said electrical bushing comprising:

an elongated casing element capable of fitting within said hole in said pressure barrier, said casing including a first cylindrical portion with a large diameter, a second cylindrical portion with a small diameter, and a conical intermediate portion therebetween, said casing being adapted to fit within said hole so as to establish and fix the positioning of the casing relative to said barrier, said casing including a centrally disposed bore extending longitudinally therethrough from a first end thereof on said first cylindrical portion thereof to a bottom portion located in said casing between the ends of the latter, said bottom thus facing toward said first end of said casing, said casing also having a plurality of individual bore holes extending longitudinally through the casing from the second end thereof on said second cylindrical portion through said bottom and into communication with said centrally disposed bore, said bore holes each being of sufficient diameter to acccommodate an insulated conductor element therein;

an insulator plate disposed in said centrally disposed bore on said bottom and presenting an upper surface facing in the same direction as said bottom, said plate having a plurality of individual bore holes extending therethrough in a direction longitudinally of the casing from said bottom and through said surface, there being a corresponding bore hole in said plate for each of the bore holes of the casing, said corresponding bore holes of the plate and of the casing being disposed in longitudinal alignment, said bore holes of the plate each having a first length adjacent said surface which is smaller in diameter than the remaining length thereof, each said remaining length having a diameter which is substantially the same as the diameter of the corresponding bore hole of the casing for accommodating an insulated conductor element therein, said first lengths each having a diameter suitable for accommmodating an uninsulated conductor element therein; and

a deformable, resilient, elastic plug disposed in said centrally disposed bore on said surface of the plate, said plug being of a shape and size to sealingly contact the inner peripheral surface of said bore adjacent said surface of the plate and being adapted for having uninsulated conductor elements inserted therethrough in a manner such that the material of the plug will be in contact with the uninsulated conductor elements, whereby when said plug is forced toward said plate, the plug tends to expand laterally and into sealing contact with respect to said peripheral surface and the uninsulated conductor elements when extending through the plug.