Thermal switch short circuiting device for arrester systems

Claim 2

A unitary thermal switch comprising electrically conductive means; a pair of conductors, one of said conductors being in electrical contact with said conductive means, the other conductor being spaced from said one conductor and insulated from said conductive means; conductive plunger means in electrical contact with said one conductor and biased toward a contacting position with said other conductor; thermally fusible insulator means interposed between said plunger and other conductor, which fuses to permit said plunger means to contact said other conductor when subjected to heating to short the switch; and means defining an air gap between said conductors to protect the switch in the event of voltage overloads.

Claim 3

The switch of claim 1, wherein said air gap means includes a pair of conductive layers, an insulating layer interposed between said conducting layers and defining an aperture therein to form said air gap.

Claim 4

The switch of claim 1, wherein said air gap means is internal of said thermal switch.

Claim 5

The switch of claim 3, wherein said air gap means is external to said thermal switch.

Claim 6

The switch of claim 1, wherein said air gap is between said other conductor and said conductive means.

Claim 7

The switch of claim 1, wherein said air gap is between said other conductor and said plunger.

Claim 8

The switch of claim 1, wherein said thermally fusible insulator means is a plastic.

Claim 9

The switch of claim 1, wherein said thermally fusible insulator means is heat-shrinkable plastic.

Claim 10

The switch of claim 1, wherein said thermally fusible insulator means is a fluoropolymer.

Claim 11

The switch of claim 1, wherein said integral insulator-fusible means is disc shaped.

Claim 12

The switch of claim 10, wherein said air gap is between said other conductor and said conductive means.

Claim 13

The switch of claim 1, wherein said other conductor includes a protrusion at its free end, said protrusion abutting said integral insulator-fusible means to pass therethrough when said fusible means yields.

Claim 14

The switch of claim 1, wherein said integral insulator-fusible means is ring shaped.

Claim 15

The switch of claim 13, wherein said air gap is between said other conductor and said plunger; the thickness of said ring defining air gap distance.

Claim 16

The switch of claim 1, wherein said air gap means includes means for controlling the location of arcing therein.

Claim 17

The switch of claim 15, wherein said arc control means includes a protrusion extending from at least one of the arcing surfaces in the air gap means.

Claim 18

The switch of claim 16, wherein a pair of protrusions are provided.

Claim 19

The switch of claim 1, wherein said air gap means includes a pair of surfaces having a layer selected from the group consisting of copper oxide and graphite, said layer being located at least in the area of the arcing surfaces of the air gap.

Claim 20

The switch of claim 1, wherein said conductive means is a tubular housing.

Claim 21

A surge arrester system comprising: (i) a gas filled surge arrester having at least two electrodes defining and ionization gap therebetween; (ii) thermal switch means positioned on said arrester in thermally responsive relationship with said ionization gap and electrically coupled to said electrodes, said thermal switch being thermally responsive to short circuit said electrodes in the event of sustained overload of said arrester, said thermal switch means being a unitary enclosed assembly comprising electrically conductive means; a pair of conductors, one of said conductors being in electrical contact with said conductive means, the other conductor being spaced from said one conductor and insulated from said conductive means; conductive plunger means in electrical contact with said one conductor and biased toward a contacting position with said other conductor; thermally fusible insulator means interposed between said plunger and other conductor, which fuses to permit said plunger to contact said other conductor when subjected to heating to short the switch; and (iii) air gap means electrically connected across said electrodes to provide back-up protection to said surge arrester.

Claim 22

A surge arrester system comprising: (i) a gas filled surge arrester having at least two electrodes defining and ionization gap therebetween; (ii) thermal switch means positioned on said arrester in thermally responsive relationship with said ionization gap and electrically coupled to said electrodes, said thermal switch being thermally responsive to short circuit said electrodes in the event of sustained overload of said arrester, said thermal switch means being a unitary enclosed assembly comprising electrically conductive means; a pair of conductors, one of said conductors being in electrical contact with said conductive means, the other conductor being spaced from said one conductor and insulated from said conductive means; conductive plunger means in electrical contact with said one conductor and biased toward a contacting position with said other conductor; thermally fusible insulator means interposed between said plunger and other conductor, which fuses to permit said plunger to contact said other conductor when subjected to heating to short the switch; and (iii) air gap means electrically connected across said electrodes to provide back-up protection to said surge arrester.

Claim 23

A system of claim 1, wherein said air gap means and thermal switch are integral.

Claim 24

A system of claim 21, wherein said air gap means is within said thermal switch.

Claim 25

A system of claim 21, wherein said air gap means is external to said thermal switch.

Claim 26

A system of claim 1, wherein said surge arrester has two line electrodes and a ground electrode, and a thermal switch and air gap means is provided across each line electrode and ground electrode.

Claim 27

A system of claim 1, wherein said air gap is about 3 mils.

Claim 28

A system of claim 1, wherein said air gap has a strike voltage in the range of 550-850 volts D.C.

Claim 29

The system of claim 1, wherein said air gap is between said other conductor and said conductive means.

Claim 30

The system of claim 1, wherein said air gap is between said other conductor and said plunger.

Claim 31

The system of claim 1, wherein said thermally fusible means is a plastic.

Claim 32

The system of claim 1, wherein said fusible means is heat-shrinkable plastic.

Claim 33

The system of claim 1, wherein said fusible means is a fluoropolymer.

Claim 34

The system of claim 1, wherein said integral insulator-fusible means is disc shaped.

Claim 35

The system of claim 32, wherein said air gap is between said other conductor and said conductive means.

Claim 36

The system of claim 1, wherein said integral insulator-fusible means is ring shaped.

Claim 37

The system of claim 1, wherein said thermal switch means is in direct contact with said surge arrester.

Claim 38

The system of claim 1, wherein a pair of air gaps and a pair of thermal switch means are provided, said air gaps and said switch means being contained within a single enclosure.

Claim 39

The system of claim 1, wherein said conductive means is a tubular housing.

Claim 40

A fail-safe arrester system comprising: (i) a gas filled surge arrester having at least two electrodes defining an ionization gap therebetween; (ii) thermal switch means positioned on said arrester in thermally responsive relationship with said ionization gap and electrically coupled to said electrodes, said thermal switch being thermally responsive to short circuit said electrodes in the event of sustained overload of said arrester, said thermal switch means being a unitary assembly comprising electrically conductive means; a pair of conductors, one of said conductors being in electrical contact with said conductive means, the other conductor being spaced from said one conductor and insulated from said conductive means; conductive plunger means in electrical contact with said one conductor and biased toward a contacting position with said other conductor; thermally fusible insulator means interposed between said plunger and other conductor, which fuses to permit said plunger to contact said other conductor when subjected to heating to short the switch; and means defining an air gap between said conductors to protect the switch in the event of voltage overloads; and (iii) module means for retaining said arrester, switch means and air gap means, said module means also including terminal means for connecting said electrodes to the circuit to be protected, said terminal means also being adapted to serve as the junction interconnecting said circuit and the network supplying same, whereby in the absence of said module means said interconnection cannot be made.

Claim 41

A fail-safe arrester system comprising: (i) a gas filled surge arrester having at least two electrodes defining an ionization gap therebetween; (ii) thermal switch means positioned on said arrester in thermally responsive relationship with said ionization gap and electrically coupled to said electrodes, said thermal switch being thermally responsive to short circuit said electrodes in the event of sustained overload of said arrester, said thermal switch means being a unitary assembly comprising electrically conductive means; a pair of conductors, one of said conductors being in electrical contact with said conductive means, the other conductor being spaced from said one conductor and insulated from said conductive means; conductive plunger means in electrical contact with said one conductor and biased toward a contacting position with said other conductor; thermally fusible insulator means interposed between said plunger and other conductor, which fuses to permit said plunger to contact said other conductor when subjected to heating to short the switch; and means defining an air gap between said conductors to protect the switch in the event of voltage overloads; and (iii) module means for retaining said arrester, switch means and air gap means, said module means also including terminal means for connecting said electrodes to the circuit to be protected, said terminal means also being adapted to serve as the junction interconnecting said circuit and the network supplying same, whereby in the absence of said module means said interconnection cannot be made.

Claim 42

A surge arrester system comprising: (i) a gas filled surge arrester having at least two electrodes defining an ionization gap therebetween; (ii) thermal switch means in thermally responsive relationship with said ionization gap and electrically coupled to said electrodes, said thermal switch being thermally responsive to short circuit said electrodes in the event of sustained overload of said arrester; said thermal switch means comprising electrically conductive means; a pair of conductors, one of said conductors being in electrical contact with said conductive means, the other conductor being spaced from said one conductor and insulated from said conductive means; conductive plunger means in electrical contact with said one conductor and biased toward a contacting position with said other conductor; integral insulator thermally fusible means interposed between said plunger and other conductor and operative to permit said plunger to contact said other conductor when subjected to heating to short the switch, said other conductor including a protrusion at its free end, said protrusion abutting said integral insulator-fusible means to pass therethrough when said fusible means yields, and means defining an air gap between said conductors to protect the switch in the event of voltage overloads.

Claim 43

A surge arrester system comprising: (i) a gas filled surge arrester having at least two electrodes defining an ionization gap therebetween; (ii) thermal switch means in thermally responsive relationship with said ionization gap and electrically coupled to said electrodes, said thermal switch being thermally responsive to short circuit said electrodes in the event of sustained overload of said arrester; said thermal switch means comprising electrically conductive means; a pair of conductors, one of said conductors being in electrical contact with said conductive means, the other conductor being spaced from said one conductor and insulated from said conductive means; conductive plunger means in electrical contact with said one conductor and biased toward a contacting position with said other conductor; integral insulator thermally fusible means interposed between said plunger and other conductor and operative to permit said plunger to contact said other conductor when subjected to heating to short the switch, said other conductor including a protrusion at its free end, said protrusion abutting said integral insulator-fusible means to pass therethrough when said fusible means yields, and means defining an air gap between said conductors to protect the switch in the event of voltage overloads.

Claim 44

A system of claim 39, wherein said air gap means and thermal switch are integral.

Claim 45

A system of claim 40, wherein said air gap means is within said thermal switch.

Claim 46

A system of claim 39, wherein said surge arrester has two line electrodes and a ground electrode, and a thermal switch and air gap means is provided across each line electrode and ground electrode.

Claim 47

A system of claim 39, wherein said air gap is about 3 mils.

Claim 48

A system of claim 39, wherein said air gap has a strike voltage in the range of 550-850 volts D.C.

Claim 49

The system of claim 39, wherein said air gap is between said other conductor and said conductive means.

Claim 50

The system of claim 39, wherein said integral insulator-fusible means is a plastic.

Claim 51

The system of claim 39, wherein said integral insulator-fusible means is heat-shrinkable plastic.

Claim 52

The system of claim 39, wherein said integral insulator-fusible means is a fluoropolymer.

Claim 53

The system of claim 39, wherein said integral insulator-fusible means is disc shaped.

Claim 54

The system of claim 49, wherein said air gap is between said other conductor and said conductive means.

Claim 55

The system of claim 39, wherein said thermal switch means is in direct contact with said surge arrester.

Claim 56

The system of claim 39, wherein said conductive means is a tubular housing.

Claim 57

A unitary thermal switch comprising: electrically conductive means; a pair of conductors, one of said conductors being in electrical contact with said conductive means, the other conductor being spaced from said one conductor and insulated from said conductive means; conductive plunger means in electrical contact with said one conductor and biased toward a contacting position with said other conductor; integral insulator-fusible means interposed between said plunger and other conductor and operative to permit said plunger means to contact said other conductor when subjected to heating to short the switch; means defining an air gap between said conductors to protect the switch in the event of voltage overloads; and said other conductor including a protrusion at its free end, said protrusion abutting said integral insulator-fusible means to pass therethrough when said fusible means yields.

Claim 58

A unitary thermal switch comprising: electrically conductive means; a pair of conductors, one of said conductors being in electrical contact with said conductive means, the other conductor being spaced from said one conductor and insulated from said conductive means; conductive plunger means in electrical contact with said one conductor and biased toward a contacting position with said other conductor; integral insulator-fusible means interposed between said plunger and other conductor and operative to permit said plunger means to contact said other conductor when subjected to heating to short the switch; means defining an air gap between said conductors to protect the switch in the event of voltage overloads; and said other conductor including a protrusion at its free end, said protrusion abutting said integral insulator-fusible means to pass therethrough when said fusible means yields.

Claim 59

The switch of claim 53, wherein said air gap means is internal of said thermal switch.

Claim 60

The switch of claim 53, wherein said conductive means is a tubular housing.

Claim 61

The switch of claim 53, wherein said air gap is between said other conductor and said conductive means.

Claim 62

The switch of claim 53, wherein said integral insulator-fusible means is a plastic.

Claim 63

The switch of claim 53, wherein said integral insulator-fusible means is heat-shrinkable plastic.

Claim 64

The switch of claim 53, wherein said integral insulator-fusible means is a fluoropolymer.

Claim 65

The switch of claim 53, wherein said integral insulator-fusible means is disc shaped.

Claim 66

The switch of claim 53, wherein said air gap is between said other conductor and said conductive means.

Claim 67

The switch of claim 53, wherein said air gap means includes a pair of surfaces having a layer selected from the group consisting of copper oxide and graphite, said layer being located at least in the area of the arcing surfaces of the air gap.

Claim 68

A switch of claim 53, wherein said conductive plunger means is a compression spring.