Abstract: A cylindrical back washing purification apparatus comprises a main body (1), a cylindrical through hole (2) transversely provided in the main body (1), a plunger (4) slidably connected in the axial direction arranged in the through hole (2), a feed channel (6) and a discharge channel (8) connected with the through hole (2) on the main body (1). The outer peripheral portion of the foreside of the plunger (4) is concaved inward to form an annular cavity (10) with the inner wall of the through hole (2), the annular cavity (10) is connected with the feed channel (6), a “L”-type hole (12) which is connected with the discharge channel (8) is provided on the plunger (4) from fore to back in the axial direction, filtering holes (14) for connecting the annular cavity (10) with the “L”-type hole (12) are opened on the concaved peripheral face of the plunger (4) in the radial direction, a detachable filter screen (15) is coupled with the concaved peripheral face of the plunger (4).

Abstract: A resonant converter includes first and second input terminals for applying an input voltage and first and second output terminals for providing an output voltage. A transformer includes a primary winding and a secondary winding, where both the primary winding and the secondary winding have a first and a second terminal. A series resonant circuit includes a capacitive element and the primary winding of the transformer. A switching circuit is connected between the input terminals and the series resonant circuit. A rectifier circuit is connected between the secondary winding and the output terminals. A clamping circuit is connected between one of the first and second terminals of the primary winding and the input terminals.

Abstract: A cylindrical back washing purification apparatus comprises a main body (1), a cylindrical through hole (2) transversely provided in the main body (1), a plunger (4) slidably connected in the axial direction arranged in the through hole (2), a feed channel (6) and a discharge channel (8) connected with the through hole (2) on the main body (1). The outer peripheral portion of the foreside of the plunger (4) is concaved inward to form an annular cavity (10) with the inner wall of the through hole (2), the annular cavity (10) is connected with the feed channel (6), a “L”-type hole (12) which is connected with the discharge channel (8) is provided on the plunger (4) from fore to back in the axial direction, filtering holes (14) for connecting the annular cavity (10) with the “L”-type hole (12) are opened on the concaved peripheral face of the plunger (4) in the radial direction, a detachable filter screen (15) is coupled with the concaved peripheral face of the plunger (4).