Title:
MANUFACTURE OF VACUUM VALVE
Document Type and Number:
Japanese Patent JP3683921
Kind Code:
B2
Abstract:
PURPOSE: To secure productivity and to enhance a withstand voltage characteristic of a vacuum valve without deteriorating an insulation recovery characteristic after current interruption by melting and setting part of the surface portion of each of the pair of contacts in a vacuum, and deoxidizing the surface layer portions of the contacts.
CONSTITUTION: The contacts 21a, 21b of a vacuum valve 10 are shaped by cutting and placed in a vacuum having degrees vacuum of 1×10-3Pa or less, and then a discharge is caused at an amount of charge of O.01 to 0.5coulomb/ cm2 per surface area to melt their surface layers. This discharge is effected on a moving cathode spot, and although temperature reaches about 4°C, the life of the discharge is several μ seconds and so only the surface layer portions of the contacts are melted while the insides and the junction of the contacts are not heated. Therefore, a withstand voltage characteristic can be enhanced without deteriorating an insulation recovery characteristic after current interruption by which only gas adsorbed to the surfaces of the contacts can be removed.
Inventors:
Mitsutaka Homma
Hiromichi Somei
Hiromichi Somei
Application Number:
JP25864994A
Publication Date:
August 17, 2005
Filing Date:
October 25, 1994
Export Citation:
Assignee:
Toshiba Corporation
International Classes:
C21D3/02; H01H11/04; H01H33/66; H01H1/02; (IPC1-7): H01H11/04; C21D3/02; H01H33/66
Domestic Patent References:
| JP60136118A | ||||
| JP63141226A | ||||
| JP2030021A | ||||
| JP4190526A | ||||
| JP38233A | ||||
| JP4312723A | ||||
| JP831276A | ||||
| JP4043521A | ||||
| JP54056178A | ||||
| JP48088476A | ||||
| JP8022734A |
Attorney, Agent or Firm:
Hiroshi Horiguchi
Hideaki Togawa
Hideaki Togawa