Chamber pressure

About: Chamber pressure is a research topic. Over the lifetime, 2988 publications have been published within this topic receiving 30725 citations.

Pilot regulator for valves

Abstract: A pilot regulator has a main housing with a sensing chamber and a separate receiving chamber. The sensing chamber connects to the system for sensing. The receiving chamber is adapted to connect its inlet to the system upstream of the pilot and to the load line of the valve to be controlled and to connect its outlet downstream thereof, a cartridge containing a complete valve is removably received in the receiving chamber in position to control flow therethrough between the inlet and outlet. And a mechanism is disclosed for opening and closing the valve in response to sensing chamber pressure changes. The cartridge with its valve are removable as a unit for repair, mode change or replacement without disturbing connections to system.

Luminescence lifetime response of pressure-sensitive paint to a pressure transient

Abstract: Pressure-sensitive paint (PSP) is used to acquire high-fidelity images of steads pressure distributions across surfaces. The PSP luminescence emission response to excitation light depends in a straightforward way on the oxygen concentration (hence air pressure) and the irradiance incident on the PSP lumiphores. Often, however, the phenomenon of interest is unsteady. During a rapid change in pressure. the oxygen concentration within a PSP layer varies with depth. Moreover, the excitation irradiance varies with depth as a result of attenuation, and this affects signal generation when the spatial distribution of oxygen is also changing. Prior studies have been reported on the transient response of PSP using the radiometric technique to detect pressure, we have extended the study by applying a luminescence lifetime technique. Oxygen concentration as a function of time and depth are obtained by solving the mass diffusion equation. with appropriate initial and boundary conditions. We develop a luminescence emission model that takes the spatially varying oxygen concentration and excitation absorption profile into account and relate pressure to the lifetime of the luminescence emission. Oxygen concentration is governed by mass diffusion of oxygen through a PSP layer during a rapid change in pressure, and the absorption of excitation light is governed by Beer's law. The significance of both the mass diffusivity and the optical depth of PSP are assessed. A numerical method was used to solve the mass diffusion equation that allows modeling of the oxygen concentration within the PSP given an arbitrary pressure function. We have used a double-image digital camera to acquire PSP emission lifetime data from several paint thicknesses during a rapid change in pressure. These data were compared to the results predicted by the model.

Sputtering method and apparatus

Abstract: Substrate heating by plasma electron bombardment during the sputtering of a thin film in a deposition chamber is considerably reduced by utilizing, as the sputtering target, an AC-excited array of parallel tubes formed from the film material. An oscillating electric field of large amplitude is established between adjacent ones of the tubes to entrap free electrons of the chamber gas and to thereby prevent the electrons from reaching the substrate. An auxiliary conductive member mounted adjacent and parallel to the array is biased with a DC voltage of selectable polarity for increasing the deposition rate of the sputtered material without altering the chamber pressure.