News

Exhaust and filling of mercury lamps

After the discharge tube is made, the air and impurities should be evacuated, and a certain amount of argon gas (1 mol = 1.33.3 Newtons/square meter) and a certain amount of mercury should be filled. Some production methods are to bake the discharge tube at a high temperature of several hundred degrees Celsius and heat the electrode to complete the exhaust process. Another simple and effective method is to transfer the discharge tube directly from the seal to the exhaust table. At this time, the temperature of the discharge tube has risen to a higher level than other processes. At this time, the inert gas is repeatedly filled and discharged for flushing, and then the filling and sealing process is carried out. The gas used is generally 99.95% argon. Argon is the most ideal inert gas to be filled. Nitrogen and xenon have very weak excitation ability in mercury discharge, which will affect the discharge efficiency. If neon and helium are used, the starting voltage requirement is higher and the light output is lower. It is very important to control the filling pressure. Lower pressure helps start; higher pressure can improve lumen maintenance.

The amount of mercury to be filled varies with the rated power and structure of the lamp. The standard amount is: about 15 mg for an 80-watt lamp and about 60 mg for a 400-watt lamp. The amount of mercury to be filled must be accurately calculated first, and all mercury must be evaporated during discharge. As long as the coldest point of the discharge tube is above a certain temperature, the density of the vapor can be basically stable, so the performance of the lamp is rarely affected by the tube wall temperature and load. The operation of the automatic mercury filling machine is mainly to perform quantitative distribution through a capillary tube of a pre-calculated length or a container of a certain capacity.

PREVIOUS：Working principle of mercury lamp NEXT：Ultra-high pressure mercury lamp