Sodium Vapour Lamp

出典: くみこみックス

Sodium Vapour Lamp consists of a discharge tube produced from a heat resistant glass, chicken runs for sale containing a little amount of metallic sodium, neon gas and two electrodes, Neon gas is added to commence the discharge and to create adequate heat to vaporize advertiser the sodium. Since of law pressure inside the tube, a sufficiently lengthy tube required to acquire far more light. To decrease the general dimension of the lamp, this tube is generally bent into U-shape.

The light created by this lamp is yellowish which is created at its optimum pressure of about .004mm of mercury. This pressure is obtained at a temperature of about 280 C and so it becomes essential to preserve this temperature. For this goal the U-tube is enclosed in a double walled flask to prevent shed of heat. The double walled flask is interchangeable and can be fitted on to yet another U-tube. Whilst replacing the inner U-tube one particular have to be very careful due to the fact if it is broken and sodium comes in make contact with with moisture, it may possibly result in fire.

All electric discharge lamps need a higher voltage at the time of starting and low voltage in the course of operation. Typically, sodium portable chicken run vapour lamps are operated by a high leakage reactance transformer. At starting a high voltage of about 450 volts is applied across the lamp which is sufficient to start off the discharge. When the lamp is completely operative following 10 - 15 minutes, the voltage across it falls to about 150 volts. Because of the high reactance of circuit, the power issue is low and hence a p.f improvement capacitor is connected.

The efficiency of a low pressure sodium vapour lamp is extremely high (about 40 - 50 lumens/watt) and it produces a light of particular wavelength having yellow color. Sodium lamps are mainly employed for street, high way and airfield lighting exactly where color distinction is not so needed.