Method and apparatus for cleaning filter means

Claim 1

In dust control apparatus having dust transporting means and including means operatively connected to differential pressure generating means for establishing air flow therethrough; filter means interposed to filter said air flow, the improvement comprising: (a) housing means having opposed filter support means mountably retaining said filter means in a tensioned relationship therebetween, a first port formed in said housing means and defining an air inlet thereto, and a plenum chamber within said housing means in communication with the clean air side of said filter means and a second port formed in said housing means defining a clean air outlet from said plenum chamber, said differential pressure generating means establishing air flow from said inlet, across said filter means and through said plenumchamber to said outlet; (b) said filter means comprising at least one filter element with said at least one filter element being a generally flexible structure having a longitudinal axis and with a surface thereof being disposed within said plenum chamber; (c) shaker frame means, and means coupling said shaker frame to one end of said at least one filter element in a direction generally along the longitudinal axis of said at least one element; (d) stroking means operatively coupled to said shaker frame means for imparting reciprocatory stroking motion to said shaker frame with a component of said stroking motion being generally along the longitudinal axis of said at least one filter element, the stroke length of said stroking means being sufficient to move said shaker frame means toward said filter support means a distance to impart alternate tension and relaxation in said at least one filter element, said stroking means providing stroking motion to said at least one filter element at a frequency selected such that standing wave motion is generated in said at least one filter element with said standing wave being an integral number of one-half wave lengths along the length thereof and with motion in said at least one filter element being at least partially along an axis normal to said longitudinal axis.

Claim 18

A method of removing filter cake from the surface of a flexible filter element wherein said flexible filter element is retained between a pair of opposed relatively movable mounts, and wherein said filter element has an elongated axis extending between said relatively movable mounts, said method comprising: (a) establishing a tension force across said filter element along said elongated axis thereof; (b) stroking at least one of said relatively movable mounts at a predetermined amplitude and at a predetermined frequency; (c) said predetermined amplitude being sufficient to impart intermittent periods of relaxation in said filter element, and relieve said tension force; and (d) said predetermined frequency being selected to provide a frequency such that standing wave motion is generated in said filter element with said standing wave being an integral number of one-half wave lingths along the length thereof and with motion in said filter element being at least partially along an axis normal to said elongated axis in the alternate periods of relaxation and tension induced along the longitudinal axis of said filter element.

Claim 19

A method of removing filter cake from the surface of a flexible filter element wherein said flexible filter element is retained between a pair of opposed relatively movable mounts, and wherein said filter element has an elongated axis extending between said relatively movable mounts, said method comprising: (a) establishing a tension force across said filter element along said elongated axis thereof; (b) stroking at least one of said relatively movable mounts at a predetermined amplitude and at a predetermined frequency; (c) said predetermined amplitude being sufficient to impart intermittent periods of relaxation in said filter element, and relieve said tension force; and (d) said predetermined frequency being selected to provide a frequency such that standing wave motion is generated in said filter element with said standing wave being an integral number of one-half wave lingths along the length thereof and with motion in said filter element being at least partially along an axis normal to said elongated axis in the alternate periods of relaxation and tension induced along the longitudinal axis of said filter element.