Addtime： 2020-07-08 Browse times： 2519
Although the failures of vacuum pumps are various, most of the failures can be eliminated. Sometimes, for some production applications, a new pump still feels that its ultimate vacuum is not high enough, and maintenance workers can try to improve it as much as possible to improve some of the previous maintenance methods, steps, and analysis of key parts. A solution can be found.
Some pumps are not very low in terms of their ultimate vacuum index, but they are expected to be improved in production. How should we proceed? For a new 2X-30 rotary vane oil seal machine below Vacuum pump repair experience can be used for reference. When the pump was first tested, no major problems were found. It is used for evacuation alone in production, hoping to stably reach more than 75 divisions of thermocouple vacuum gauge (equivalent to 5*10-4 Torr measured by McGee gauge), but in fact it is not much lower than desired.
When repaired, the gap size of the main parts was measured after disassembly: rotor tangent point gap 0.04mm, high vacuum chamber double-sided gap 0.07mm, low vacuum chamber double-sided gap 0.08mm, rotor is 0.02mm shorter than the rotor. These data are normal.
The repair of this pump can be considered to reduce its gap tolerance. First, try to change its eccentric value: replace the intermediate shaft sleeve with an eccentric sleeve to reduce the upper tangent point clearance to 0.02mm; grind the pump cavity of the high vacuum chamber to 0.03mm, and grind the pump cavity of the low vacuum chamber to 0.04mm. After cleaning, put it upside down on the platform for assembly (without positioning pins). While assembling, move the pump wheel by hand, and tighten the fastening screws on the principle of even diagonals. According to experience, if the rotor is perfectly round in appearance, when turning the pump wheel, no matter what point it is, there should be no feeling of blocking and effort; but if the assembly is not correct or the appearance of the rotor is oval, when turning the pump wheel, it will The feeling that the half-round wheel is heavy and the half-round wheel is light occurs. The assembly gap of the pump is reduced very little. When the assembly is a little careless, the installation is not correct. In this way, due to friction and heat, it is easy to get stuck or damaged during operation. Therefore, we must assemble carefully and carefully. After the installation is finished, the vacuum degree is measured by a thermocouple vacuum gauge up to 82 grids, which is equivalent to 8*10-3 Torr from the curve and 2*10-4 Torr by the McGee gauge. After running for a period of time, the degree of vacuum has increased slightly. This example illustrates:
①The assembly of the rotor and the rotor is very important, and the gap between the upper tangent point of the rotor and the pump cavity, the gap between the rotor and the end cover, that is, the double-sided gap of the high and low vacuum chamber and the rotor tangent point gap are repairs and The key in manufacturing. Even so, if the pump is not properly assembled, the material of the pump is too poor, and there is a risk of jamming or damage. Therefore, it should be decided by experiment in practice, and should not be treated uniformly.
②Generally for pumps with poor vacuum degree, proper adjustment of assembly gap and oil circuit can get better results.
③Gap measurement should be careful and accurate. Except that the measuring tool should be calibrated to meet the specified accuracy, the workpiece should be cleaned and dried, and the measurement should be repeated several times. Take good notes. Then combine all aspects of the pump to determine the grinding size.
When testing the pump performance, the thermocouple vacuum gauge should be calibrated.
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