Patent ID: 7364653

Claim:
A filtration system comprising: a plurality of filters, each filter having an unfiltered fluid inlet, an unfiltered fluid outlet, a filtered fluid outlet, and a filtration medium and defining a filter flowpath between the unfiltered fluid inlet and the unfiltered fluid outlet for tangential filtration by the filtration medium of fluid passing through the filter flowpath, wherein the plurality of filters includes a first group of at least one but not all of the plurality of filters and a second group including the filters not in the first group; a first manifold connected to the unfiltered fluid inlet of each of the plurality of filters; a second manifold connected to the unfiltered fluid outlet of each of the plurality of filters; a first continuous flowpath comprising: the filter flowpaths of the plurality of filters, the first and second manifolds, a first pump, and a fluid circuit coupled between the first pump and the first manifold and further coupled between the second manifold and the first pump, wherein the first pump is arranged with the fluid circuit to circulate fluid around the first continuous flowpath in parallel through the filter flowpaths of the plurality of filters, a portion of the fluid passing from the unfiltered fluid inlet along one side of the filter medium to the unfiltered fluid outlet of each of the filters and a portion of the fluid passing from the unfiltered fluid inlet through the filter medium of each filter and leaving each filter via the filtered fluid outlet; a second continuous flowpath comprising: the filter flowpath of each filter in the first group, a second pump, and a fluid circuit coupled between the second pump and the unfiltered fluid inlet of each filter of the first filter group and further coupled between the unfiltered fluid outlet of each filter of the first filter group and the second pump, wherein the second pump is arranged with the fluid circuit to circulate fluid around the second continuous flowpath through each filter flowpath of the first filter group, a portion of the fluid passing from the unfiltered fluid inlet along one side of the filter medium to the unfiltered fluid outlet of each filter of the first filter group, and a portion of the fluid passing from the unfiltered fluid inlet through the filter medium of each filter of the first filter group and leaving each filter via the filtered fluid outlet, wherein the second continuous flowpath has a lower volume than the first continuous flow path; and a valve arrangement coupled to the first and second continuous flowpaths and selectively operable in a first state to circulate fluid around the first continuous flowpath and in a second state to circulate fluid around the second continuous flowpath and including a bypass to pass fluid from the first and second manifolds and the second filter group into the second continuous flow path in response to fluid flow around the second continuous flow path.