Topic
Chamber pressure
About: Chamber pressure is a research topic. Over the lifetime, 2988 publications have been published within this topic receiving 30725 citations.
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Patent•
22 Mar 2001
TL;DR: In this paper, a method for speeding workpiece thoughput in a low pressure, high temperature semiconductor processing reactor was described, which includes loading a workpiece into a chamber at atmospheric pressure, bringing the chamber down to an intermediate pressure, and heating the wafer while under the intermediate pressure (115, 230).
Abstract: A method is disclosed for speeding workpiece thoughput in a low pressure, high temperature semiconductor processing reactor. The method includes loading (100, 200) a workpiece into a chamber at atmospheric pressure, bringing the chamber down to an intermediate pressure (110, 210, 225), and heating the wafer while under the intermediate pressure (115, 230). The chamber is then pumped down to the operating pressure (125, 235). The preferred embodiments involve single wafer plasma ashers, where a wafer is loaded (100) onto lift pins at a position above a wafer chuck, the pressure is rapidly pumped down (110) to about 40 Torr by rapidly opening and closing an isolation valve, and the wafer is simultaneously lowered (115) to the heated chuck. Alternatively, the wafer can be pre-processed to remove (220) an implanted photoresist crust at a first temperature and the chamber then backfilled (225) to about 40 Torr for further heating (230) to close to the chuck temperature. At 40 Torr, the heat transfer from the chuck to the wafer is relatively fast, but still slow enough to avoid thermal shock. In the interim, the pump line is further pumped down to operating pressure (about 1 Torr) behind the isolation valve. The chamber pressure is then again reduced (235) by opening the isolation valve, and the wafer is processed (240).
10 citations
TL;DR: In this article, the loading paths of chamber pressure and pre-bulging pressure were designed and optimized by numerical simulations and experiments, and effects of loading paths were obtained and analyzed for thickness, stress and defects.
Abstract: To improve the poor plasticity of 2024 aluminum alloy sheet, which causes wrinkle and fracture in conventional deep drawing of complexshaped components, hydromechanical deep drawing (HDD) with pre-bulging was investigated. The loading paths of chamber pressure and pre-bulging pressure were designed and optimized by numerical simulations and experiments, and effects of loading paths were obtained and analyzed for thickness, stress and defects. A reasonable loading path was determined. Thickness is more uniform when pre-bulging pressure is 2 MPa and chamber pressure is 15 MPa. The suspending area of a blank wrinkles easily between the punch and the die when pre-bulging pressure is smaller than 1.5 MPa; fracture occurs for the suspending area of blank between the punch and the die when pre-bulging pressure is larger than 8 MPa. The results show that a helpful friction can be generated, the stress state can be improved, and fracture and wrinkle can be avoided by a reasonable pre-bulging in the suspending area of the blank for a complex-shaped component. The uniformity of thickness and forming limit can be enhanced.
10 citations
TL;DR: In this paper, the experimental investigation and theoretical analysis on the unstable performances of transpiration cooling with phase change was performed at four mainstream temperatures and four coolant injection ratios in the electric heating wind tunnel at University of Science and Technology of China.
10 citations
02 Aug 2009
TL;DR: In this paper, the effects of the port number and distance between ports on a regression rate were taken into account to investigate combustion characteristics of cylindrical multi-port grain of a hybrid rocket motor.
Abstract: The purpose of this experimental research is to investigate combustion characteristics of cylindrical multi-port grain of a hybrid rocket motor. The physical model of concern includes an oxidizer supply system, a multi-port fuel grain, and a combustor with preand post chamber. Gaseous oxygen and polymer (PE and PMMA) are applied as the oxidizer and the fuel, respectively. In geometric points of view, the effects of the port number and the distance between ports on a regression rate are taken into account. Internal combustion performance was analyzed using smalland large scale motors: one is motor diameter of 50 mm and the other is 96 mm, with oxidizer mass flux ranging from 10 kg/m-sec to 300 kg/msec for both cases. The port number positively shifts the O/F ratio to near its optimum value as well as the oxidizer mass flux to the typical range influenced by pressure effects so that the fuel regression rate becomes fast as the port number increases to a typical number up to 4 ports. Emphasis was placed on merging effects among fuel gain ports having 4 and 5 port to analyze how port geometrical configuration may influence the chamber pressure and thrust drop.
10 citations
Dissertation•
01 Jan 2015
TL;DR: In this article, the authors examined excavation chamber pressure behavior within a 17.5 m diameter earth pressure balance tunnel boring machine (EPBM) used on the Alaskan Way viaduct replacement tunnel project in Seattle, Washington, USA.
Abstract: This thesis examines excavation chamber pressure behavior within a 17.5 m diameter earth pressure balance tunnel boring machine (EPBM) used on the Alaskan Way viaduct replacement tunnel project in Seattle, Washington, USA. The study examines behavior during the first 150 rings of tunneling (10% of the project) through till and till-like deposits, granular soils, and cohesive silts and clays. A portable laboratory was established on the project site to characterize key properties of the muck as it came through the screw conveyor and onto the belt conveyor, namely, vane shear strength, density, slump, consistency and grain size distribution. Testing was performed on representative muck samples from a series of rings. Machine data, including excavation chamber pressures, screw conveyor pressures, soil conditioning inputs, and key operating parameters such as thrust, cutterhead and screw conveyor torque, cutterhead and screw conveyor rotation speeds, etc., were studied in great detail to determine what parameters influenced chamber pressures and how. The results of detailed EPBM data analysis supported with field lab test results from muck testing produced a number of key findings. Excavation chamber pressures measured by 12 pressure sensors varied up to 3 to 3.5 bar from crown to invert. Chamber pressures varied during ring mining and standstill, and the responses from different heights in the chamber were synchronous. Chamber pressure variations during excavation were influenced by changes in volumetric flow rates into the chamber via the cutterhead and out of the chamber via the screw conveyor. Increases/decreases in net volumetric inflow caused increases/decreases in chamber pressure. The magnitudes of pressure changes were linearly correlated to the net volumetric flow rate changes. A quantitative analysis of these data produced estimates of chamber material compressibility that could provide useful information in assessing the effectiveness of soil conditioning. An understanding of the role of cutterhead force on EPBM advance rate was developed. By estimating the change in cutterhead force (thrust force minus chamber pressure force), a relationship to advance rate was observed, i.e., increased cutterhead force increased the advance rate. The same was not true between thrust force and advance rate. The increases/decreases in chamber pressure mentioned above were also related to decreases/increases in cutterhead force through the mechanical concept of compressibility. Increases in chamber pressure resulting from material compression and stiffening means that the chamber soil takes on more of the force at the face (owing to relative stiffness increase). The cutterhead force therefore decreases. The behavior also works in reverse. The vertical gradients of chamber pressure provided significant insight into muck consistency and behavior. Magnitudes of gradients matched reasonably well with muck densities. Changes in gradient both locally and globally provide information about muck density under pressure and whether the…
10 citations