Abstract: This disclosure pertains to a filter apparatus utilizing a helically wound spring element adapted with a cap closing one end thereof. The other end of the spring is fed with the liquid or gas which is to be filtered. The spring may be permanently magnetized, or when electrically energized, be an electromagnet which magnetically constrains particles possessing magnetic properties within the chamber formed by the capped spring. The core of the spring may contain permanent magnets therein. The spring may be adjustably tensioned by an axially aligned screw which selectively compresses or elongates the spring thereby altering the opening size between the turns of the spring. The adjustment screw may be fabricated from a magnetic material causing the magnetic field to be concentrated thereabout, increasing the effectiveness of retaining magnetically sensitive particles within the confines of the spring.