Development of dry vacuum pump.

Vacuum Gauge to Vacuum Pump Valve

CFD Simulation of a Dry Scroll Vacuum Pump Including Leakage Flows

One challenge for the numerical simulation of a dry scroll vacuum pump is the discretization of the chamber volume, which changes with time. In addition, the flow characteristics are very complex including the leakage flow caused by radial and axial gaps between the rotors and the housing. For engineers and designers it is imperative to understand the influence of such leakage flows on the effi...

A Case Study of Autoregressive Modelling and Order Selection for a Dry Vacuum Pump

Oil-free dry-vacuum pumps are prevalent in semiconductor plants worldwide today. The popularity of such pumps has grown over the years but little research has been done in the area of condition-monitoring of dry-vacuum pumps. Fault detection of one such pump through the use of AutoRegressive (AR) modelling technique and spectral analysis of vibration and acoustic data has been studied. The test...

effect of oral presentation on development of l2 learners grammar

this experimental study has been conducted to test the effect of oral presentation on the development of l2 learners grammar. but this oral presentation is not merely a deductive instruction of grammatical points, in this presentation two hypotheses of krashen (input and low filter hypotheses), stevicks viewpoints on grammar explanation and correction and widdowsons opinion on limited use of l1...

Prediction of Vacuum Pump Degradation in Semiconductor Processing

This paper addresses the issue of vacuum pump degradation in semiconductor manufacturing. The ability to identify the current level of vacuum pump degradation and predict the Remaining-Useful-Life (RUL) of a dry vacuum pump would allow manufacturers to schedule pump swaps at convenient times, and reduce the instances of unexpected pump failures, which can incur significant costs. In this paper,...