Controllable vacuum source

摘要

The present invention relates to a vacuum source for providing vacuum to at least a first vacuum drain through conduits, comprising at least a first and a second vacuum pump. The vacuum source comprises a control system adapted to detect the consumed airflow, and to control the operation of each of the first and second vacuum pump based on the detected airflow.

主权项

1. A method for providing vacuum from a vacuum source to at least a first vacuum drain through conduits of a vacuum pump system, said method comprising:
detecting a consumed airflow within defined airflow ranges that comprise first, second, and third airflow ranges with different respective lower end values and higher upper end values, the first airflow range being less than the second airflow range, and the second airflow range is less than the third airflow range, wherein the consumed airflow is measured with an airflow gauge; with a control system, providing vacuum to at least the first vacuum drain through the conduits of the vacuum pump system by the control system automatically controlling a rotation speed of each of at least a first vacuum pump and a second vacuum pump, said first and second vacuum pumps respectively each i) having an optimal rotation speed, ii) having a maximum rotation speed, and iii) being rotation speed controllable to plural non-zero speeds, wherein the optimal rotation speed is less than the maximum rotation speed, the lower end value of the second airflow range being less than a maximum airflow capacity of the first vacuum pump; while detecting said consumed airflow in the first airflow range, the control system controlling a vacuum level of the provided vacuum by keeping said second vacuum pump turned off and controlling the rotation speed of said first vacuum pump to vary at plural non-zero speeds below the maximum airflow capacity of the first vacuum pump; and when detecting the consumed airflow to have increased from the first airflow range to be at the lower end value of the second airflow range, the control system providing the vacuum by starting the second vacuum pump so that the second vacuum pump is started before the maximum airflow capacity of the first vacuum pump is reached, and with said control system keeping both the first and second vacuum pumps running, said control system controlling the rotation speed of said first vacuum pump at a first fixed rotation speed less than the maximum rotation speed, and second vacuum pump to vary at non-zero speeds within the second airflow range to thereby maintain the vacuum level in the system.