XIX IMEKO World Congress

Vacuum technology is one of the established advanced technologies, of present age, in the field of research and industry. Having numerous applications, in the areas of human activities, one is concerned with a relatively large vacuum chamber where pressure distribution is, usually, not uniform during dynamic gas flow. To minimize the pressure non-uniformities in such chambers, baffles are generally used. In the present work, rectangular-shaped baffles of different sizes are used in a cylindrical-shaped chamber of a flow-control system, developed by Korea Research Institute of Standards and Science (KRISS). The chamber is large enough and has been experimented for pressure distribution at four different points in the pressure range from 0.1 Pa to 133 Pa by using five identical Capacitance Diaphragm Gauges (CDGs). One of these gauges serves as a reference gauge and is fixed at one point while the readings of the other four gauges were recorded by using baffles of various sizes and, at the same time, producing the pressure dynamically in the chamber. It is worth mentioning that before installation, all of these gauges were calibrated on Ultrasonic Interferometer Manometer (UIM). The data, thus obtained, along with relative deviations of the gauges’ readings are plotted for all the three baffles which represent the behavior of gas pressure in this particular chamber.