Enhanced varistor-based lighting arresters

• US 6,185,813 B1
• Filed: 05/27/1999
• Issued: 02/13/2001
• Est. Priority Date: 04/12/1996
• Status: Expired due to Fees

• Current Assignee: Soule Materiel Electrique
• Original Assignee: Soule Materiel Electrique
• Inventors: Donnola, Jean-Michel
• Primary Examiner(s): Young, Lee
• Assistant Examiner(s): SMITH, SEAN PRENTISS
• Application Number:
  US09/171,217
• Time in Patent Office: 628 Days
• Field of Search: 338/21, 338/13, 338/14, 338/15, 338/20, 361/117, 361/126-128, 361/130, 361/119, 361/120, 361/331, 361/420, 174/178, 296/13, 296/11, 296/101
• US Class Current: 29/613
• CPC Class Codes: H01C 7/12 Overvoltage protection resistors series resistors structurally associated with spark gaps H01T1/16
• CPC Class Codes: Y10T 29/49087 with envelope or housing

Abstract

The present invention relates to a method of manufacturing a lightning arrester, the method being of the type comprising steps consisting in making a stack of varistors (100), and in forming a cover (300) made of a composite material over the stack of varistors (100), said method being characterized by the fact that the step of forming a cover (300) made of a composite material consists in placing a woven fiber fabric (310) on the outside of the stack of varistors (100) and in contact therewith, in placing a flexible outer cover (400) on the outside of the stack of varistors (100), and in injecting a material (350) suitable for impregnating the fiber fabric (310) into the annular space formed between the stack of varistors (100) and the flexible outer cover (400).

Claims

1. A method of manufacturing a lightning arrester, comprising:

making a stack of varisters;

placing a woven fiber fabric on the outside of the stack of varisters and in contact therewith;

placing a flexible outer layer on the outside of the woven fiber fabric; and

injecting a material suitable for impregnating the fiber fabric through a bore into the annular space formed between the stack of varisters and the flexible outer layer so as to form a cover made of a composite material over the stack of varisters by impregnating the fiber fabric with the injected material.

2. A method according to claim 1, wherein the outer cover is a cover provided with annular fins defining zones of higher rigidity than said cover disposed around the stack of varistors.

3. A method according to claim 1 wherein the impregnation material is injected through contact parts placed at the ends of the stack of varistors.

4. A method according to claim 1 wherein the impregnation material is a synthetic resin.

5. A method according to claim 4, wherein the impregnation material is injected via at least one bore provided in a contact part at a first end of the stack of varistors, the contact part at the second end of the stack of varistors being provided with at least one corresponding bore for removing air contained in said annular space prior to injection.

6. A method according to claim 1 further comprising a prior step consisting in treating the inside surface of the flexible outer cover, thereby providing chemical bridging between the material of the flexible outer cover and the injected material.

7. A method according to claim 1 wherein the impregnation material contains a compound suitable for reinforcing the bond between the injected material and the outer cover.

8. A method according to claim 1 wherein the outer cover is made of an elastomer.

9. A method according to claim 5, wherein the bores formed in the end contact parts for injection purposes open out in respective annular grooves provided in the contact parts.

10. A method according to claim 1 wherein the fiber fabric has fibers parallel to the axis of the stack of varistors, and fibers transverse thereto.

11. A method according to claim 1 wherein the fiber fabric has a mesh size approximately in the range 3.5 mm to 5 mm.

12. A method according to claim 1 wherein the fiber fabric, placed on the outside of the stack of varistors prior to injecting the material into the annular space formed between the stack of varistors and the flexible outer cover is a fabric that is pre-impregnated with resin.

13. A method according to claim 5 further comprising closing off each injection bore, so as to complete the sealing of the lightning arrester once injection of the material is finished.

14. A method according to claim 1 further comprising placing two ties in the form of loops into grooves provided in contact parts disposed at the ends of the stack of varistors, on the outside of the fiber fabric to hold said fabric.

15. A method according to claim 14, wherein the two ties come from a common tape that runs along the stack of varistors over the outside of the fiber fabric.

16. A method according to claim 15, wherein the tape is wound spirally around the fiber fabric between the two ties.

17. A method according to claim 16, wherein tape extends rectilinearly parallel to the axis of the lightning arrester, over the outside of the fiber fabric between the two ties, preferably facing the free edge of the fiber fabric.

18. A method according to claim 1 further comprising placing a film that is impermeable to the injected resin around the stack of varistors prior to the injection step.

19. A method according to claim 4, wherein the impregnation material is an epoxy resin.

20. A method according to claim 4, wherein the impregnation material is a polyester resin.

21. A method according to claim 5, wherein the bore provided in the second part is diametrically opposite from the injection bore.

22. A method according to claim 6, wherein treating consists in applying a mechanical treatment.

23. A method according to claim 6, wherein treating consists in applying a chemical treatment.

24. A method according to claim 6, wherein treating consists in depositing a primer.

25. A method according to claim 8, wherein the outer cover is made of silicone rubber.

26. A method according to claim 13, wherein said injection bore is closed by means of a stopper.

27. A method according to claim 13, wherein said injection bore is closed by means of a sealing compound.

28. A method of manufacturing a lightning arrester, comprising:

making a stack of varistors;

forming a cover made of a composite material over the stack of varistors by placing a woven fiber fabric on the outside of the stack of varistors and in contact therewith; and

placing a flexible outer cover on the outside of the woven fiber fabric, wherein for forming said cover made of a composite material, the method further comprises;

injecting a synthetic resin suitable for impregnating the fiber fabric into the annular space formed between the stack of varistors and the flexible outer cover, via at least one bore provided in a contact part at a first end of the stack of varistors, the contact part at the second end of the stack of varistors being provided with at least one corresponding bore for removing air contained in said annular space prior to injection.

29. A method according to claim 28, wherein the bore provided in the second contact part is diametrically opposite from the injection bore.

30. A method according to claim 28, wherein the bores formed in the end contact parts for injection purposes open out in respective annular grooves provided in the contact parts.

31. A method according to claim 28 further comprising closing off each injection bore, so as to complete the sealing of the lightning arrester once injection of the material is finished.