# US 4,396,970 A · Overvoltage surge arrester with predetermined creepage path > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,396,970 A - Document ID: US4396970A - Status: Granted - Kind: A - Application number: 06/224,467 - Filed: 1981-01-12 - Granted: 1983-08-02 - Earliest claimed: 1981-01-12 - Assignees: TII Industries, Inc. - Inventors: Frank G. Scudner, Jr. - Web page: https://patentgrep.com/patent/US4396970A ## CPC - H01T 1/20: Means for starting arc or facilitating ignition of spark gap - H01T 4/12: hermetically sealed - H01T: SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES (overvoltage protection circuits H02H) ## Abstract An overvoltage surge arrester which has a reduced turn on time and is suitable for use at low voltage levels to protect electronic equipment, such as telephone repeaters and the like; this protective device includes a core of semiconductor material provided with a predetermined surface creepage path thereacross and electrically conductive terminals (electrodes) disposed on each end thereof. The conductive terminals or electrodes may extend towards each other to provide a secondary, backup discharge gap. The surge arrester may be used as an integral part of a gas filled device with the conductive electrodes connected between a line electrode and ground electrode thereof. ## Claims ### Claim 1 A low voltage surge arrester, comprising: (a) at lease one core member of semiconductor material having two contact surfaces, said core member being provided with a predetermined surface creepage path thereacross; and (b) a pair of electrodes, one of said pair of electrodes being in electrically conductive contact with a respective one of said contact surfaces of the core member, said electrodes extending towards each other forming a predetermined discharge gap therebetween; and (c) spring means disposed between at least one electrode and said semiconductor material to insure electrical contact between said electrodes and said semiconductor material. ### Claim 2 (depends on 1) The arrester according to claim 1 further including an insulating spacer disposed between said semiconductor material and one of said electrodes. ### Claim 3 (depends on 1) The arrester according to claim 1 further including an insulating housing enclosing said semiconductor material and said discharge gap in intimate contact with said electrodes. ### Claim 4 (depends on 3) The arrester according to claim 3 further including a gas disposed within said housing, said housing being hermetically sealed to said electrodes. ### Claim 5 An low voltage surge arrester comprising: (a) a solid cylindrically-shaped core of semiconductor material having a predetermined surface creepage path; and (b) first and second cup-shaped electrodes disposed on both ends of said core, said electrodes being in electrical conducting contact with said semiconductor core material, extending over the ends thereof and separated by a predetermined distance to form a gap therebetween. ### Claim 6 A low voltage surge arrester, comprising: (a) an electrically conductive base member; (b) a semiconductor core member centrally disposed on and in intimate conductive contact with said base member; and (c) a plurality of conductive electrodes in electrical contact with said core member and disposed proximate the outer edge of said core member providing a predetermined surface creepage path from each said electrode and across the surface of said core member to said base member. ### Claim 7 (depends on 6) A low voltage surge arrester accordng to claim 6 further including a cover portion hermetically sealed to said base portion and each said electrode, said cover portion providing an insulating medium around each said electrode to prevent conductivity therebetween. ### Claim 8 (depends on 7) A surge arrester according to claim 7 further including gas disposed within said volume encompassed by said cover and base portions. ### Claim 9 (depends on 6) A surge arrester according to claim 6 further including a plurality of core members disposed between each said respective electrode and said base portion. ### Claim 10 (depends on 9) A surge arrester according to claim 9 wherein said core members are cylindrically shaped. ### Claim 11 (depends on 9) A surge arrester according to claim 9 wherein said core member is spherically-shaped. ### Claim 12 (depends on 9) A surge arrester according to claim 9 wherein said core member is generally rectangularly shaped. ### Claim 13 An overvoltage surge arrester, comprising: (a) a pair of metallic terminals extending towards each other and providing a gap therebetween; (b) a common terminal spaced away from said pair of metallic terminals and concentric therewith; and (c) a pair of semiconductor washers having an insulator disposed therebetween and positioned within said gap, the circumference of said washers in electrical conductive contact with said common terminal providing a predetermined surface creepage path between said common terminal and said end terminals. ### Claim 14 An overvoltage surge arrester comprising: (a) a pair of metallic terminals extending towards each other and providing a gap therebetween; (b) a common terminal spaced away from said pair of metallic terminals and concentric therewith; and (c) a pair of semiconductor washers, each in electrically conductive contact with said common terminal and concentric with said end terminals, said semiconductor washers having a centrally disposed aperture each circumscribing one of said pair of terminals. ### Claim 15 (depends on 14) A surge arrester according to claim 14 wherein one of said semiconductor washers is in conductive contact with each said pair of terminals. ### Claim 16 (depends on 13, 14) An overvoltage surge arrestor according to claims 13 or 14 wherein said common terminal and said pair of terminals are hermetically sealed to an insulating concentric cylinder. ### Claim 17 (depends on 13, 14) A surge arrester according to claims 13 or 14 further including a gas within the volume of said common concentric terminal. ### Claim 18 A low voltage surge arrester, comprising: (a) at least one core member of semiconductor material having two contact surfaces, said core member being provided with a predetermined surface creepage path thereacross; (b) a pair of electrodes, one of said pair of electrodes being an electrically conductive contact with a respective one of said contact surfaces of the core member, said electrodes extending towards each other forming a predetermined discharge gap therebetween; and (c) insulating spacing means disposed between said semiconductor material and one of said electrodes. ### Claim 19 A low voltage surge arrester, comprising: (a) at least one core member of semiconductor material having two contact surfaces, said core member being provided with a predetermined surface creepage path thereacross; (b) a pair of electrodes, one of said pair of electrodes being an electrically conductive contact with a respective one of said contact surfaces of the core member, said electrodes extending towards each other forming a predetermined discharge gap therebetween; and (c) insulated housing means enclosing said semiconductor material and said discharge gap in intimate contact with said electrodes.