Research On Application Software Development In Vacuum System Design

Although there are many types of vacuum application equipments, a vacuum system to pumping the gas in vacuum chamber is necessary. During designing, designers have to calculate the parameters such as pressure, vacuum pump speed, pipeline geometry size and pump-down time repeatedly to establish the vacuum system meeting the requirement. To the artificial calculation there will be errors and time wasting. Therefore, how to come up with an accurate, effective vacuum system quickly becomes a specialized study. Vacuum system design software will be the necessary development of the vacuum system design.At present, the designers calculate the formula to finish the vacuum system design. But many formulas are semi-empirical formula and some parameter valve in these formulas is difficult to determine. This paper will discuss how to determine the average pressure value of the pipe in viscous flow, and the relative error is analyzed when the average pressure value is approximate to the inlet pressure of pipeline. Through the analysis, we can see that if the vacuum pumping speed is constant and smaller or pipeline is shorter, the relative error is smaller; greater speed and longer pipeline will lead to greater relative error. In addition, Monte Carlo method has been used to simulate the transmission probability of round straight pipe and right-angle elbow pipe in molecular flow. By the simulated results, we can seen that the simulated results of round straight pipe and the approximate solution of Clausing equation are in good agreement, and the simulated results of right-angle elbow pipe and the simulated results of Davis’equivalent method are in good agreement, the relative error is smaller. As a result, these two calculated methods can be used to calculate the transmission probability of round straight and right-angle elbow pipe.According to the vacuum system theoretical knowledge and design process, this paper use Visual Basic6.0and Access Database to structure the application software. This application software is made up of start module, vacuum chamber parameter settings module, vacuum pump parameter setting module, pump-down calculation module, save engineering module and other aided module. This paper introduces the arithmetic and technical processing of main module. And some examples had been calculated by the software program to obtain the pump-down time curve, compared with the pump-down time curve of experimental measurement. A good agreement between the calculation and experiment, and the relative error is small, curvilinear trend are nearly the same. It means that the accuracy of the code by comparison between the calculation and experiment. Moreover, use application software can be convenient to change the parameters setting of the vacuum system, until the design results achieve satisfaction. Finally, users can output the calculated parameters and the calculation results curved to the Word document, so that users can convenient to edit, preservation, printing, etc. Using the software to design vacuum system, can improve the design efficiency greatly and shorten the design cycle.