There is provided a new static mixer with a low pressure loss and a high agitating/mixing efficiency. The mixer comprises in the midst of a fluid passage a mixing body having a larger diameter than the fluid passage. The mixing body has a mixing body cylinder portion, an inlet hollow portion having an inlet port fitted to the cylinder portion, and a outlet hollow portion having an outlet port. An impingement cylinder having an diameter larger than a diameter of the outlet port is disposed within the mixing body such that its opening is positioned in a confronting relation with the inlet port. A plurality of recesses are provided at at least one of an inner side portion of bottom of the impingement cylinder, an inner surface portion of the hollow inlet port, an inner surface portion of the hollow outlet port, an inner circumferential portion of a cylindrical portion of the impingement cylinder, and an inner circumferential surface portion of the cylindrical portion of the mixing body.

The invention relates to a method and apparatus (1) for continuously mixing two flows (3, 5)., in particular, a first larger flow (3) and a second smaller flow (5). The mixing operation is carried out in a throttle (6) which is placed in the conduit (2) of the first flow. A bent conduit (4) discharges the second flow in the throttle of the conduit. The conduit (4) of the second flow (5) is terminated with a pipe bend (8) and a mouth (9) with a washer (10) such that the two flows (3,5) face towards one another. Additionally, a gap (11) is provided between the washer 10 and the mouth (9) in order to spread the 2.sup.nd flow uniformly around the mouth (9) of the pipe bend (8) and out into the counter-flowing first flow (3).

A blending system for dispersing continuously in a fixed proportion of a dispersed first solids flow into a second bulk solids flow thereby forming a homogeneous solids flow. The system includes an upright vessel having an outlet for the homogeneous solids at its lower extremity. One or more blending stages are disposed within the vessel above the outlet. The blending stage has an inverted Vee element with inclined side surfaces mounted centrally within the vessel and with its apex pointed upwardly. A first inlet for the first solids resides vertically above the apex of the element. A second inlet for the second solids has a discharge opening about the first inlet and displaced laterally from the apex of the element. The dispersed first solids are supplied at a certain flow rate through the first inlet to flow about the apex of the element and downwardly along its side surfaces. The second solids are supplied at a certain flow rate through the second inlet to flow downwardly along the side surfaces of the element whereat the dispersed first solids are uniformly distributed into the second solids to produce a homogeneous solids flow removed through the outlet from the vessel.

An arrangement for mixing fluid streams in a duct, said arrangement comprising: at least one mixing device having front side and back side and positioned within said duct through which a first major stream travels, the at least one mixing device determining a total cross-sectional area which is significantly lower than that of the duct so as to allow for the passage of said first major stream, in which the at least one mixing device is a solid plate provided with one or more protrusions extending outward from the main solid plate body.

A method for the mixing of fluid streams in a duct comprising positioning at least one mixing device having a front side and a back side within said duct through which a first major stream travels, the at least one mixing device determining a total cross-sectional area which is significantly lower than that of the duct so as to allow for the passage of said first major stream, whereby the at least one mixing device is a solid plate provided with one or more protrusions extending outward from the main solid plate body.