Electric arc-blast nozzle and a circuit breaker including such a nozzle

Abstract

A nozzle with an electric arc-blast having a median part of a first dielectric material and two end parts. The nozzle includes an insert of a second dielectric material, chosen from among: a composite material including a fluorocarbon polymer matrix and inorganic filler A chosen from among a sulfur, a ceramic and an oxide (SiO2, TiO2, Al2CoO4, ZnO, BaTiO3 and P2O5), in a percentage weight ranging between 0.1% and 10%, and/or at least one inorganic filler B (a graphite, a mica, a glass and a fluoride), in a percentage weight ranging between 5% and 50%, and a ceramic material including compound(s) (a carbide, a boride and an oxide).

Claims

1. An electric arc-blast nozzle for a circuit breaker comprising: a neck-forming median part internally defining an axial passage for cutting an electric arc and formed with a first dielectric material obtained from a first composition comprising a fluorocarbon polymer matrix, two end parts extending on either side of the median part which are respectively intended to receive arc contacts that can be axially moved in relation to each other, between a circuit breaker opening position in which the arc contacts are separated from each other and a circuit breaker closing position in which the arc contacts are in contact with each other and in which one of the arc contacts partially closes the axial passage of the median part, an electric arc cut-off gas circulating in the axial passage of the median part to cut the electric arc that is likely to be formed during movement of the arc contacts from the closing position to the opening position of the circuit breaker, and an insert, that defines a downstream area of the axial passage of the median part considering a direction of a flow of the electric arc cut-off gas and is, also, formed with a second dielectric material, different from the first dielectric material and from among: a composite material obtained from a second composition comprising a fluorocarbon polymer matrix and: at least one inorganic filler A comprising at least one of MoS2, Sb2Ss or Sb2S3, a ceramic, BN, and an oxide comprising at least one of Si02, Ti02, AhCoQ4, ZnO, BaTiQ3 and P205, in a percentage weight ranging between 0.1% and 10%, with respect to a total weight of the second composition, and/or at least one inorganic filler B comprising at least one of a graphite, a mica, a glass and a fluoride, in a percentage weight ranging between 5% and 50%, with respect to the total weight of the second composition, and a ceramic material obtained from a third composition comprising at least one compound comprising at least one of a carbide, a boride and an oxide.

2. The nozzle according to claim 1, wherein the inorganic filler A is chosen from BN and Si02.

3. The nozzle according to claim 1, wherein the percentage weight of the inorganic filler(s) A ranges between 0.2% and 5%, with respect to the total weight of the second composition.

4. The nozzle according to claim 1, wherein the percentage weight of the inorganic filler(s) B ranges between 10% and 30%, with respect to the total weight of the second composition.

5. The nozzle according to claim 1, wherein the composite material has a gradient of percentage weights of inorganic filler(s) A and/or B in the fluorocarbon polymer matrix which increases in the direction of the flow of the electric arc cut-off gas.

6. The nozzle according to claim 1, wherein the second composition comprises only one inorganic filler A.

7. The nozzle according to claim 1, wherein the compound of the third composition comprising at least one of SiC, ZrC, HfC, ZrB2, HfB2, SiO2, and ZrO2.

8. The nozzle according to claim 1, wherein the third composition also comprises at least one inorganic filler.

9. The nozzle according to claim 1, wherein the first composition further comprises at least one inorganic filler C in percentage weight, with respect to the total weight of the first composition, of less than or equal to 10%, except where the inorganic filler C comprising inorganic fillers A and/or B, in which case the percentage weight of the inorganic fillers C is less than the percentage weight of the inorganic filler(s) A and/or B of the second composition.

10. The nozzle according to claim 9, wherein the inorganic filler C comprising at least one of MoS2 and AhCo04.

11. The nozzle according to claim 1, wherein the first composition does not comprise the inorganic filler.

12. The nozzle according to claim 1, wherein the fluorocarbon polymer of the first and second compositions is chosen from polytetrafluoroethylene, a copolymer of ethylene and tetrafluoroethylene and, a polyfluoride of vinylidene.

13. The nozzle according to claim 1, wherein a length of the insert present in the median part represents no more than 30%.

14. The nozzle according to claim 1, wherein the insert forms a section of the median part.

15. The nozzle according to claim 1, wherein the insert extends up to a downstream end of the median part.

16. The nozzle according to claim 15, wherein the insert extends beyond the downstream end of the median part in at least one area of an internal peripheral surface of the end part disposed downstream considering the direction of the flow of the electric arc cut-off gas, the internal peripheral surface being in a shape of a truncated cone.

17. The nozzle according to claim 1, wherein the end part disposed upstream and, where required, at least a portion of the end part disposed downstream are formed with the first dielectric material, the upstream and downstream disposition of the end parts considering the direction of the flow of the electric arc cut-off gas.

18. The nozzle according to claim 1, further comprising a sheath disposed on an external surface of each of the two end parts and the neck-forming median part.

19. A high voltage circuit breaker comprising: at least two arc contacts and that can be axially moved in relation to each other, between the circuit breaker opening position in which the arc contacts are separated from each other and the circuit breaker closing position in which the arc contacts are in contact with each other, the electric arc-blast nozzle defined according to claim 1, and the electric arc to cut-off gas circulating in the axial passage of the median part of the nozzle to cut the electric arc that is likely to be formed during the movement of the arc contacts from the circuit breaker closing position to the circuit breaker closing position.

20. A circuit breaker according to claim 19, wherein the electric arc cut-off gas comprising of at least one of carbon dioxide CO2, sulfur hexafluoride SF6 and is a gaseous mix comprising CO2.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a partial schematic longitudinal section of a circuit breaker comprising an electric art blast nozzle according to the prior art.

(2) FIG. 2 shows a partial schematic longitudinal section of a circuit breaker comprising an electric art blast nozzle according to the invention, the nozzle being equipped with an insert according to the first conformation.

(3) FIG. 3 shows a partial schematic longitudinal section of a circuit breaker comprising an electric art blast nozzle according to the invention, the nozzle being equipped with an insert according to the second conformation.

(4) FIG. 4 shows a partial schematic longitudinal section of a circuit breaker comprising an electric art blast nozzle according to the invention, the nozzle being equipped with an insert according to the third conformation.

(5) FIG. 5 shows a partial schematic longitudinal section of a circuit breaker comprising an electric art blast nozzle according to the invention, the nozzle being equipped with an insert according to fourth conformation and a sheath.

(6) FIG. 6 shows a partial schematic longitudinal section of a circuit breaker comprising an electric art blast nozzle according to the invention, the nozzle being equipped with an insert according to the fifth conformation.

(7) FIG. 7 shows a partial schematic longitudinal section of a circuit breaker comprising an electric art blast nozzle according to the invention, the nozzle being equipped with an insert according to the sixth conformation.

(8) It is specified that the common elements in FIGS. 1 to 7 are marked with the same numerical reference.

DETAILED DESCRIPTION

(9) FIG. 1 shows a part of the circuit breaker. This circuit breaker comprises: i. at least two arc contacts 1 and 3 axially mobile in relation to each other, along an axis A, between a circuit breaker opening position in which the arc contacts 1 and 3 are separated from each other and a circuit breaker closing position in which the arc contacts 1 and 3 are in contact with each other, and ii. an electric arc-blast nozzle 5 conforming to prior art.

(10) This nozzle 5 comprises a neck-forming median part 7, an end part 9 disposed upstream and an end part 11 disposed downstream, the upstream and downstream disposition of the end parts 9 and 11 being considered in the direction of the flow of the electric arc cut-off gas. These two end parts 9 and 11 extend on either side of the median part 7. These parts 7, 9 and 11 have a symmetrical revolution around axis A.

(11) The median part 7 internally defines an axial passage 13 of the electric arc cut-off, this axial passage 13 comprising an inlet 13a and an outlet 13b. This median part 7 is called the neck-forming median part 7, due to the internal section of this axial passage 13, which is smaller than the internal section of each of the end parts 9 and 11.

(12) The end parts 9 and 11 respectively receive and surround the arc contacts 1 and 3.

(13) The median part 9 disposed upstream channels the cut-off gas situated upstream and intended to blast the electric arc, whereas the median part 11 disposed downstream evacuates and circulates the blast gas situated downstream, upstream and downstream being defined with reference to the direction of the flow of the electric arc cut-off gas.

(14) The end part 9 may have a cover 10, with this cover 10 surrounding arc contact 1.

(15) In FIG. 1, the arc contacts 1 and 3 are separated from each other and therefore correspond to the opening position of the circuit breaker.

(16) When the arc contacts 1 and 3 are in contact with each other, in the closing position of the circuit breaker, the arc contact 3 closes the axial passage 13 of the median part 7 partially.

(17) There is an electric arc cut-off gas routing channel 15 between the arc contact 1 and the wall of the end part 9, which allows the circulation of this gas in the axial passage 13 of the median part 7, from its inlet 13a to its outlet 13b, to cut an electric arc that is likely to be formed during the movement of arc contacts 1 and 3 from the closing position to the opening position of the circuit breaker.

(18) The end part 11 has a truncated cone shaped part 11a disposed in the extension of the median part 7 situated with respect to the outlet 13b of the axial passage 13, this truncated cone shaped part 11a being followed by a cylindrical part 11b.

(19) The neck-forming median part 7 as well as the cover 10 and the end parts 9 and 11 are made from a first dielectric material, which has good mechanical properties and thermal resistance. Typically, this first dielectric material is obtained from a first composition comprising a fluorocarbon polymer matrix, classically a PTFE matrix.

(20) This first composition may comprise one or more inorganic fillers C. When they are present, the inorganic fillers classically represent a percentage weight that may go up to 10% of the total weight of the first composition, this percentage weight ranging more generally between 0.01% and 5% with respect to the total weight of the first composition.

(21) Like FIG. 1, FIG. 2 represents part of the circuit breaker that comprises at least two arc contacts 1 and 3 that are axially movable with respect to each other, between an opening position and a closing position, as well as an electric arc-blast nozzle 20 that complies with the invention.

(22) Like nozzle 5 from FIG. 1, the nozzle 20 according to the invention represented in FIG. 2 comprises a neck-forming median part 27 and two end parts 9 and 11 extending on either side of the median part 27. This neck-forming median part 27 internally defines an electric arc cut-off axial passage 13 equipped with an inlet 13a and an outlet 13b.

(23) Unlike the nozzle 5 from FIG. 1, nozzle 20 from FIG. 2 comprises an insert 22 defining a downstream area 22a of the axial passage 13 of the median part 27 considering the direction of the flow of the cut-off gas, direction that is established at the inlet 13a towards the outlet 13b of the axial passage 13.

(24) In FIG. 2, the insert 22 is in the form of a ring. However, nothing prohibits from giving this insert a more complex form.

(25) The insert 22 of the nozzle 20 according to the invention is formed with a second dielectric material, separate from the first dielectric material forming the median part 27 (insert 22 not included) and the end parts 9 and 11.

(26) This second dielectric material, which gives the insert 22 excellent resistance to radiation from the electric arc, is chosen from: i. a composite material obtained from a second composition comprising a fluorocarbon polymer matrix and: ii. at least one inorganic filler A chosen from among a sulfur, a ceramic and an oxide chosen from among SiO.sub.2, TiO.sub.2, Al.sub.2CoO.sub.4, ZnO, BaTiO.sub.3 and P.sub.2O.sub.5, in a percentage weight ranging between 0.1% and 10%, with respect to the total weight of the second composition, and/or iii. at least one inorganic filler B chosen from among a graphite, a mica, a glass and a fluoride, in some examples, CaF.sub.2, in a percentage weight ranging between 5% and 50%, with respect to the total weight of the second composition, and iv. a ceramic material obtained from a third composition comprising at least one compound chosen from among a carbide, a boride and an oxide.

(27) Reference should be made to the chapter on the disclosure of the invention for any specification concerning the different variants of the second and third compositions that are likely to be possible for obtaining these composite and ceramic materials constituting the second dielectric material suitable for the insert 22.

(28) As represented in FIG. 2, the length of the insert 22, considered along the A axis, represents less than 30% of the total length of the median part 27.

(29) The nozzle 20 can be manufactured using any classic procedure, for example, by overmolding the median part 27 and end parts 9 and 11 on the insert 22.

(30) FIG. 3 shows a nozzle 30 according to the invention in which the median part 37 comprises an insert 32 appearing in another conformation.

(31) More precisely, the insert 32 constitutes a section of this median part 37, which extends transversally from the internal surface of the axial passage 13 to the external surface of the median part 37.

(32) In this representation of FIG. 3, the insert 32 also extends longitudinally up to the downstream end 37a of the median part 37.

(33) FIG. 4 shows a nozzle 40 according to the invention in which the median part 47 comprises an insert 42 appearing in another conformation.

(34) The insert 42 represented in FIG. 4 extends longitudinally beyond the downstream end 47a of the median part 47 in a portion of the part shaped like a truncated cone 41a of the end part 41. Doing so, the insert 42 is located in at least one internal peripheral surface area of this part shaped like a truncated cone 41a, which makes it possible to optimize the flow of the cut-off gas.

(35) FIG. 5 shows a nozzle 50 according to the invention in which the median part 57 comprises an insert 52 appearing in another conformation.

(36) Like the insert 42 of FIG. 4, the insert 52 of FIG. 5 extends longitudinally beyond the downstream end 57a of the median part 57 up to the part shaped like a truncated cone 51a of the end part 51.

(37) The insert 52 also extends transversally from the internal surface of the axial passage 13 up to the external surface of the median part 57 and the internal surface up to the external surface of the part shaped like a truncated cone 51a.

(38) The nozzle 50 also comprises a sheath 54 disposed on the external surface of each of the two end parts 9 and 51 and the neck-forming median part 57.

(39) FIG. 6 shows a nozzle 60 according to the invention in which the median part 67 comprises an insert 62 appearing in another conformation.

(40) As in the case of insert 52 represented in FIG. 5, the insert 62 of FIG. 6 extends longitudinally beyond the downstream end 67a of the median part 67 and this, throughout the length of the end part 61.

(41) The insert 62 also extends transversally from the internal surface of the axial passage 13 up to the external surface of the median part 67 but also the internal surfaces of the parts shaped like a truncated cone 61a and end 61b up to the external surface of the end part 61.

(42) In other words, according to this fifth conformation of the nozzle 60, the insert 62 comprises the end part 61.

(43) FIG. 7 shows a nozzle 70 according to the invention in which the median part 77 comprises an insert 72 appearing in another conformation.

(44) This insert 72 extends longitudinally beyond the downstream end 77a of the median part 77 and this, throughout the length of the end part 71.

(45) The insert 72 extends transversally from the internal surface of the axial passage 13 up to the external surface of the median part 77 but also the internal surfaces of the parts shaped like a truncated cone 71a and end 71b up to the external surface of the end part 71.

(46) As shown in FIG. 7, the insert 72 is made up of three portions 72a, 72b and 72c. All these three portions 72a, 72b and 72c are formed with a second dielectric material from two compositions comprising a fluorocarbon polymer matrix and at least one inorganic filler chosen from an inorganic filler A and an inorganic filler B, with this second dielectric material having a gradient of percentage weights of inorganic filler(s) in the fluorocarbon polymer matrix, which increases considering the direction of the flow of the electric arc cut-off gas.

(47) In other words, the percentage weights of inorganic filler(s) A and/or B in the second composition of the portion 72a is less than the portion 72b, which itself being less than the portion 72c, these various percentage weights evidently remain within the intervals of the percentage weight defined above based on the nature of the inorganic filler(s) A and/or B in question.

(48) In a particularly more favorable manner, the fluorocarbon polymer(s) as well as the inorganic fillers A and/or B used in the second compositions from which the portions 72a, 72b and 72c of the insert 72 are obtained are identical.

(49) The electric arc-blast nozzles according to the invention, such as nozzles 20, 30, 40, 50, 60 and 70 respectively shown in FIGS. 2 to 7, can be completely transposed in the conventional nozzle structures. In other words, the median parts 27, 37, 47, 57, 67 and 77 and, where applicable, the end parts 41, 51, 61 and 71 can respectively replace the median part 7 and, where applicable, the end part 11 of the nozzle 5 shown in FIG. 1, without any change in the dimensions of the various parts constituting these nozzles.

(50) However, nothing stops the neck-forming median part from being extended in the longitudinal direction by a length that may go up to reaching the length of the insert in said median part. In such circumstances, the path of the arc contacts 1 and 3 may be proportionally increased.