The problem of providing a stirrer capable of more effectively shearing a fluid to be treated is addressed, by using the action of an intermittent jet stream. A stirrer is provided with a rotor having a blade and a screen, which are relatively rotated such that the fluid to be treated is discharged from the inside of the screen to the outside as an intermittent jet stream through a slit in the screen, the stirrer satisfying condition 1 and condition 2. (Condition 1) the relationship among the width b in the rotating direction of a tip part of the blade, the width s in the circumferential direction of the slit, and the width t in the circumferential direction of the screen member is b2s+t. (Condition 2) the relationship between the width b in the rotating direction of the tip part of the blade and the maximum inner diameter c of the screen is b0.1c.

A static mixer for liquids or gases includes a housing having a continuous inner surface defining a fluid flow path for liquids or gases, an inlet to the fluid flow path, and an outlet from the fluid flow path, and an insert extending longitudinally through the fluid flow path between the inlet and the outlet. The insert is elastically expansive to exert outwardly directed pressure against the continuous inner surface of the housing. In one embodiment, the insert is hollow and has deflectors dispersed therethroughout and each projecting inwardly into the fluid flow path. In another embodiment, the insert includes a helical deflector extending inwardly into the fluid flow path from the continuous inner surface, and helically about a longitudinal axis of the housing.

In a method and to a device for treating a compound, such as a chemical and/or organic and/or microorganism compound, which is carried by a liquid, the liquid is driven axially through an axial inlet (21) into a central inlet portion of a radial cavitation chamber (18) having a peripheral outlet (30), such that the liquid is diverted into the central inlet portion and flows into the radial chamber in various radial directions towards the peripheral outlet; and the liquid flow conditions between the inlet and the peripheral outlet of the radial chamber are capable of generating cavitation bubbles or pockets (31) and subsequently causing the collapse or implosion of the bubbles or pockets in order to treat the compound at least partially.

A high-shear mixing chamber is provided having a single wide slot microchannel that enables a higher throughput, less plugging, and a longer life (e.g., less wear) than typical multi-slotted mixing chambers. The provided mixing chamber may include an inlet and an outlet in fluid communication with a single wide slot microchannel (e.g., via an inlet and outlet plenum). In some aspects, the wide slot microchannel may have a stepped interior such that the wide slot microchannel has portions with different depths. The wide slot microchannel has a first surface opposite a second surface and one or more steps may be formed with the first surface alone, the second surface alone, or with both the first surface and the second surface. The steps may extend a full length of the microchannel between the inlet and outlet chambers.