IGNITION PLUG FOR COMBUSTION CHAMBERS OF POWER AND PROPULSION PLANTS Russian patent published in 2013 - IPC H01T13/00 

FIELD: electricity.

SUBSTANCE: ignition plug includes a tubular metal housing, a screen metal tube fixed inside the metal housing, a ceramic insulator tightly sealed in the tubular metal housing, a contact head that is connected by soldering to a conical cap tightly sealed to a foot of the ceramic insulator on the side of the screen ceramic tube and to the rod of a central electrode, which is arranged in inner cavity of ceramic insulator, a cylindrical cap, the bottom of which faces the rod of the central electrode and tightly sealed to ceramic insulator on its inner surface on the side of the working edge of the ignition plug, a central electrode arranged in inner cavity of cylindrical cap, which is connected to it by welding, a side electrode contact connected to the metal housing of the plug on the side of its working edge, a central electrode contact arranged immediately on central electrode so that an annular spark gap is formed between contacts of central and side electrodes on end surface of ceramic insulator. With that, the central electrode rod is connected to the cylindrical cap bottom by riveting and soldering; besides, ratio of outer diameter of cylindrical cap to thickness of its bottom is between 25 and 44; thickness of the bottom and wall of the cap does not exceed 0.2 mm; material of cylindrical cap and rod of the central electrode contains nickel (28.5-29.5)%, cobalt (17-18)% and iron (51.14-54.5)%, and ceramic insulator contains Al₂O₃ (90-94)%, SiO₂ (4-4.4)%, and CaO (1-1.6)%.

EFFECT: improving operating reliability of ignition plugs, providing exclusion of disturbance of an electric chain on a central electrode of the plug at action of increased vibration loads.

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