Particle filter with ultrasound device

A filtration method without using a reflector, comprising:

• (I) conveying fluids containing particles having a particle size of from 400 μm to ≤500 μm into and through a flow pipe and/or a wall-free flow area through a flow channel with a volume flow of 10−2 mL/sec to 105 mL/sec;
• (II) generating a standing acoustic ultrasonic field having an energy input into the flow channel of 0.25 W to 1 KW by means of ultrasonic waves of the frequency of 20 KHz to 800 MHz in the flowing fluids, whereby
• in the case of the wall-free flow area, the standing acoustic ultrasonic field is generated by at least two pairs of mutually associated and mutually opposing exciters of ultrasonic waves, wherein the imaginary connecting lines between the respective pairs intersect at an angle of 90°,
• in the case of the flow pipe, the standing acoustic ultrasonic field is generated by at least two pairs of mutually associated and mutually opposing exciters of ultrasonic waves, which pairs are arranged on the outside and/or on the inside and/or in the respective closed wall itself so that the imaginary connecting lines between the respective pairs intersect at an angle of 90°,
• (III) monitoring, modulating, and stabilizing the standing acoustic ultrasonic field by means of a feedback loop;
• (IV) (a) conveying the fluids with a volume flow of 10−2 mL/sec to 105 mL/sec in a conveying direction into and through the flow pipe and/or into and through the wall free flow area and through a fluid connection of the flow pipe and/or of the wall-free flow area to a filter having a smallest filterable particle size of 50 nm to 1000 nm and being permeated by the fluids, while (b) metering particles having a particle size of from 400 nm
• to ≤500 μm into the flow channel;
• whereby the flowing fluids with particles of particle sizes of 400 pm to ≤50 nm having a specific particle number (N/Vt)≤20%;
• and/or with particles of particle sizes of ≥200 nm to ≤400 nm having a specific particle number (N/Vt) ≤20%;
• and/or with particles of particle sizes of ≥50 nm to ≤200 nm having a specific particle number (NNt) ≥80%;
• and/or with the particles having a particle size of from 400 pm to ≤500 μm having a specific particle number (N/Vt) ≥80% are formed by aggregation and agglomeration of the particles having a particle size of 400 pm to ≤500 μm;
• (V) separating the particles having a particle size of 400 nm to ≤500 μm from the flowing fluids by the filter, after which the filtrated fluids emerging from the filter have a total specific particle number (N/Vt) below the respective detection limit and/or up to 0.1%,
• (VI) (a) channeling the particles having a particle size of 400 nm to <500 μm out of the flow channel into a branch of the flow pipe or of the wall-free flow area, while (b) exposing the particles to shock waves or standing longitudinal waves;
• and
• (VII) filtering the particles by means of a further filter, wherein N is particle number, V is volume in cubic meters, t is time in hours, and wherein the percentages given above are each based on the respective specific starter numbers (N/Vt) of the respective particles being 100%.