Filter-cleaning device and method, and fluid pulse generator particularly useful therein

A compressible fluid pulse generator comprising:

• a pressure tank having a tank inlet for inletting a pressurized fluid, a tank outlet for outletting the pressurized fluid, and a valve member normally in a closed position closing said tank outlet, but actuatable to quickly move to an open position to produce a high-pressure high-flow impulse of compressible fluid at said tank outlet;
• said valve member being in the form of a piston movable within a cylinder in said tank;
• said cylinder having a closed end, and an open end aligned with said tank outlet;
• said piston being normally urged to its closed position to close said tank outlet by the fluid pressure within the cylinder between its closed end and the piston, and being actuatable in a fast-action manner to quickly move to its open position by the release of said pressure between the piston and the closed end of the cylinder;
• said cylinder being formed with a large passageway therethrough adjacent its open end for directing the pressurized fluid within the tank to the tank outlet in the open position of the valve member and thereby for producing the high-pressure high-flow impulse of compressible fluid at the tank outlet;
• the inner diameter of the cylinder being reduced at the open end thereof aligned with said tank outlet to define an inner annular shoulder in the cylinder;
• the outer diameter of the piston being correspondingly reduced at the end thereof facing the tank outlet to define:
• an outer annular shoulder engageable with the inner annular shoulder of the cylinder in the closed position of the piston, a large diameter section on the side of said shoulder facing the closed end of the cylinder, and a smaller diameter section on the side of said shoulder facing the open end of the cylinder;
• said piston including a first sealing ring on said large diameter section, and a second sealing ring on said smaller diameter section, said sealing rings being located such that in the closed position of the piston, they are on opposite sides of said large passageway adjacent the open end of the cylinder.