Patent ID: 7396462

Claim:
A filtering device comprising: a fluid-collecting tube defining a fluid channel therein and formed with a plurality of apertures that are in fluid communication with said fluid channel; a plurality of positioning trays sleeved around said fluid-collecting tube and stacked one above the other; and a plurality of membranes alternating with said positioning trays and disposed around said fluid-collecting tube, each of said membranes being sandwiched between an adjacent pair of said positioning trays; wherein each of said positioning trays includes an annular plate that is sleeved around said fluid-collecting tube and that is formed with a plurality of annularly displaced arcuate holes around said fluid-collecting tube, each of said arcuate holes having opposite first and second ends, said annular plate of each of said positioning trays being provided with a plurality of first engaging members, each of which is disposed adjacent to said first end of a respective one of said arcuate holes, and a plurality of second engaging members, each of which is disposed adjacent to said second end of a respective one of said arcuate holes; wherein said annular plates of each adjacent pair of said positioning trays are coupled to each other and are rotatable relative to each other between a first relative position and a second relative position offset from the first relative position; and wherein said first engaging member of one of said annular plates of each adjacent pair of said positioning trays is disengaged from said second engaging member of the other of said annular plates of each adjacent pair of said positioning trays when said annular plates of each adjacent pair of said positioning trays are disposed at the first relative position, and said first engaging member of said one of said annular plates of each adjacent pair of said positioning trays engages releasably said second engaging member of the other of said annular plates of each adjacent pair of said positioning trays when said annular plates of each adjacent pair of said positioning trays are disposed at the second relative position.