How Does A High-Speed Disperser Work?

WHAT IS A HIGH-SPEED DISPERSER?

A high-speed disperser is a type of mixer used to rapidly break apart lumps of powder material, uniformly distributing and wetting them in a liquid. It is also used to dissolve soluble solids in a liquid.

HOW DOES A HIGH-SPEED DISPERSER WORK?

A high-speed disperser works on the principle of energy transfer. A disc-type blade is mounted at the bottom end of the mixing shaft and rotated at a relatively high tip speed. Tip speed is the speed at the outer tip or edge of the rotating disc. Tip speeds typical of high-speed dispersers are measured in feet per minute, calculated by multiplying the constant 3.14 times the diameter in feet of the disc times the revolutions per minute of the mixing shaft. The industry term for tip speed is peripheral velocity.

The solids and liquids are drawn into the rotating disc by the suction it creates. This suction usually results in a visible whirlpool from the top of the mixture down to the top of the disc. A similar whirlpool is created below the disc, extending from the bottom of the tank to the underside of the disc. The whirlpools are actually two individual vortices, although common industry practice refers only to the visible upper one as the vortex.

When the solids/liquid mixture enters the vortices and is sucked into the high-speed disc, the energy (horsepower used to drive the disc) is instantaneously transferred from the disc to the mixture. This intensely focused energy transfer creates tremendous, instantaneous velocity changes in the mixture as it progressively contacts the disc. Think of the mixture as a series of individual horizontal layers descending downward from the top and upward from the bottom onto the face of the rotating disc. As each layer contacts the disc, it is instantaneously accelerated from the slow-moving vortex into the high speed of the disc and projected outward away from the disc and toward the wall of the tank. The rapid tearing apart of layer upon layer of the mixture is shear force, commonly referred to as shear.