strainer

siivilä, suodatin A device through which a liquid is passed for purification, filtering or separation from solid matter; anything (including a screen or a cloth) used to strain a liquid; any device functioning as a sieve or filter - in special, a perforated screen or openwork (usually at the end of a suction pipe of a pump), used to prevent solid bodies from mixing in a liquid stream or flowline.
One who strains.
2008, Kirby I. Bland, ‎Michael G. Sarr, ‎Markus W. Büchler, General Surgery: Principles and International Practice (page 843)

An important factor with respect to recurrence of rectal prolapse is the fact that many of these patients are chronic strainers.