High Pressure Sodium Lamps With New Reserves Electrodes

In the entire Electricity Consumption,electricity consumption on road illumination takes more than 30%proportion,which,along with the domestic agenda of urbanization in China,is continually increasing.HPS is recognized as one the most widely applied and the most lumen-efficient lamps used on road illumination.To carry through the state's policies of energy saving and emission reduction,at least 10%of the electricity consumption used on illumination should be saved according to the eleventh Five-Year Plan.That further increase the lumen efficiency and longevity of currently used HPS,therefore,should remains the very significance for long lasting flourishing of society.In this sense,to investigate and develop a new electrode with better performance must be viewed as the very first step leading to that aim.The performance of the conventional electrode coated with oxides electron powders,the most frequently used one,is weak in several aspects:bad durability to ion bombardment,high work function and bad start-up properties.At the same time,the amount of emitting material is little and cannot be controlled exactly.All of the above has greatly restricted the synthesis capability of HPS.In this sense,aiming to discover a brand new type electrode which embraces a relatively lower work function and more stable emission property remains the most promising direction in the research of HPS.Based on the investigation of rare earth metal-W electrode and the traditional dispenser Ba-W electrode,this research inaugurates a brand new dispenser electrode that is innovative both in structure and combination.This new dispenser electrode primarily includes a columniform sinter and a pure tungsten rod located in the middle of the tinter.The columniform sinter is made of several compounds of W,BCT and Y₂O₃-La₂O₃-CeO₂,adequately according to prescription;suppress those mixture to a column and mount a tungsten rod axially in the column and finally sinter these elements in high temperature for several times.SEM,EDAX,voltage,luminous flux and some other photoelectricity parameters for many kinds of HPS with different prescriptions and technics have been measured.For 250W HPS,result shows that the luminous flux at 2000h is 96.32%of the original, the lumen decay is smaller than National standard(90%at 2000h) even at 5000h, when the lumen maintenance is 92.49%.Lamp voltage increased to 0.73V/1000h, much smaller than the international advanced level(1.5V/1000h) and domestic advanced level(3V/1000h).Therefore,we can estimate that the lifetime of new dispenser electrodes will be more than 3 times longer than that of the original domestic HPS lamp and twice as much as the original international HPS lamp.Due to the good performance on ignitor,the pressure of starting gas Xe in arc tube can increase from 4kPa to 36kPa,so the new HPS lamps have about 20%more lumen output than the national standard.Such results reveal that the new HPS embraces strong potentials both in energy saving and material saving.