| 摘要 |
<p>A fluid filtering system including two filter units so arranged in parallel that flow of fluid from a source to a point of usage can take place by way of only one unit at a time. Means is provided which can sense the degree of contamination of whichever one of the units is in service so that when the degree of contamination is such that the said one unit is no longer in a suitable condition for further filtering service, that means causes the by-passing of that unit and the bringing of the other unit into service. The system further includes back-flushing means which is automatically operable upon a filter unit when so by-passed for cleaning that unit. Timing means is also provided for automatically controlling the period of time during which back-flushing operation is permitted to continue.</p> |
