Clean‐Up and Pressure Effects in Low Pressure Mercury Vapor Discharges: A Reversible Electrical Clean‐Up of Mercury

1938 ◽  
Vol 9 (12) ◽  
pp. 765-777 ◽  
Author(s):  
Carl Kenty
Keyword(s):  
Mercury Vapor ◽  
Low Pressure ◽  
Pressure Effects

254 nm Radiant Efficiency of High Output Low Pressure Mercury Discharge Lamps with Neon-Argon Buffer Gas

2013 ◽  
Vol 325-326 ◽  
pp. 409-412
Author(s):  
Hao Jun Zhang ◽  
Qiu Yi Han ◽  
Shan Duan Zhang
Keyword(s):  
Mercury Vapor ◽  
Low Pressure ◽  
Input Power ◽  
Cold Spot ◽  
Outer Diameter ◽  
Buffer Gas ◽  
Uv Irradiance ◽  
Radiant Efficiency ◽  
Uv Lamps ◽  
High Output

High output low pressure mercury (LPM) discharge UV lamps have been briefly introduced. In order to measure the 254 nm radiant efficiency simply and preciously, Keitz formula was used and its advantage was illustrated. The LPM lamps had outer diameter of 19 mm (T6). The buffer gases are neon (65%) and argon (35%) with total pressure 1-10 Torr (133-1333 Pa). The lamps were operated with cold spot temperatures from 20°C to 80°C and discharge current from 0.8 A to 2.0 A. The electric field, input power, 254 nm UV irradiance and irradiance of other Hg lines from 265 to 579 nm in positive column were measured. The radiant power of each wavelength can be calibrated according to the 254 nm output and the Keitz formula. It was shown that the radiant efficiency of 254 nm can reach a maximum of above 40% at cold spot temperature 45-47 °C and current 1.6 A for filling pressure less than 3 Torr. The optimal mercury vapor pressure was 1.2 to 1.4 Pa. The output percentage of other Hg lines was below 5%. With the decrease of buffer gas pressure, the 254 nm radiant efficiency increased obviously.

STUDY OF METHODS FOR MEASURING THE OPTICAL CHARACTERISTICS OF LOW-PRESSURE MERCURY LAMPS

2021 ◽  
Author(s):  
I.I. Zheleznov
Keyword(s):  
Mercury Vapor ◽  
Low Pressure ◽  
Inert Gases ◽  
Automated System ◽  
Main Task ◽  
Radiation Sources ◽  
Current Densities ◽  
Photometric Measurements ◽  
Object Of Study

Obtaining experimental data on the electrical and photometric parameters of low-pressure tubular amalgam lamps with a discharge in a mixture of mercury vapor and inert gases at high current densities of 0.5-1.2 A/cm2 with frequencies of tens of kilohertz is one of the key problems of modern metrology. Since a full-fledged study of the properties of experimental samples of mercury lamps is impossible without a reliable method of photometric measurements, and for ozone lamps such a technique, taking into account the features of the object of study, has not yet been proposed, its development and testing is the main task of this work. Based on the analysis of existing techniques, a technique for measuring the fluxes of the 185 and 254 nm lines of a low-pressure mercury lamp is proposed, taking into account the change in the nature of the spatial distribution of radiation during operation, without directly measuring the RIC. The method proposed by the author for measuring the fluxes of ozonizing and bactericidal radiation can be used as the basis for the development of an automated system for measuring parameters and monitoring the quality of gas-discharge UV radiation sources.

Pressure Effects on the Lifetime of Gas High Density Polyethylene Pipes

2021 ◽  
Author(s):  
Yang Wang ◽  
Hui-qing Lan ◽  
Tao Meng ◽  
Bing Wang ◽  
Du du Guo ◽  
...  
Keyword(s):  
Natural Gas ◽  
Induction Time ◽  
High Density Polyethylene ◽  
Reaction Rate ◽  
Low Pressure ◽  
Gas Pressure ◽  
High Density ◽  
Pressure Effects ◽  
Polyethylene Pipes ◽  
Hdpe Pipes

Abstract The purpose of this study was to propose low gas pressure effects on lifetime of natural gas high density polyethylene (HDPE) pipes by thermal-oxidative aging (TOA). The new method to assess the lifetime of HDPE natural gas pipes is based on gas pressure testing. An approach to monitor oxidative induction time (OIT) has been used to predict lifetime. Natural gas HDPE pipes were used to evaluate the effects of low gas pres-sures on oxidative induction time. In order to emphasize the pressure effects, relatively low temperatures at 45, 55, 65 and 75 °C were utilized for the exposure. The low-pressure conditions were created using air at levels of 0, 0.1, 0.2, 0.3 and 0.4 MPa. The property of high density polyethylene pipes was effectively moni-tored using the low pressure oxidative induction time (OIT) test. The results show that the aging reaction rate of high density polyethylene pipes increased exponentially with temperature and gas pressure according to the Arrhenius equation. Analytical models were developed to predict the aging reaction rate and lifetime of natural gas HDPE pipes.

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