High-pressure sodium lamp

E.J.E. Cottaar (Inventor), P.J. Vrugt (Inventor)

    Research output: PatentPatent publication


    A high pressure sodium lamp of the invention is provided with a discharge vessel (20) which is enclosed with intervening space (1) by an outer bulb (10), which space contains a gas-fill with at least 70 mol. % nitrogen gas. Electrodes (30a, 30b) are positioned in the discharge vessel (20) and are each connected to a current supply conductor (40a, 40b) which issues from the discharge vessel (20) at a respective end (21a, 21b) thereof. The discharge vessel (20) has between the electrodes (30a, 30b) a central portion (22) with length L and volume V. The discharge vessel (20) contains an amalgam containing a weight mHg of mercury and a weight mNa of sodium, whereby the following relations are fulfilled: and in which mHg and mNa are expressed in mg, and L and V are expressed in cm and cm, respectively.; This allows for a stable operation despite temperature fluctuations in the environment, while breakdown in the outer bulb (10) and damage caused by corrosion of current supply connectors (40a, 40b) is prevented.
    Original languageEnglish
    Patent numberEP19930200664, US 55
    Publication statusPublished - 1996


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