Mixer paddle-agitator

Pascal 1. A SI unit of measurement of pressure equal to the pressure resulting from a force of 1 Newton acting uniformly over an area of 1 square meter. It is used to denote the pressure of mechanical behavior of materials under pressure. 2, See computer Pascal, paste A material compound and adhesive composition of semisolid consistency, usually dispersed in water. See mixer, double-arm mixer, paddle agitator extruder paste. 

Several manufacturers are selling dissolvers or mixers, generally stainless steel tanks, sometimes with heating systems and a mixing paddle agitator. These systems... 

Propeller Mixer n A device comprising a rotating shaft with a propeller at its end, used for mixing relatively low-viscosity dispersions and holding contents of tanks in suspension. The propellers, of which there may be two or three on a single shaft, resemble boat propellers, having two to four broad, curved lobes. See also Paddle Agitator. 

The momentum is transferred by normal stresses, in which the transfer is parallel to the direction of flow. This category includes the paddle, propeller, and turbo mixer agitators. 

Propeller/paddle mixers are used to blend or agitate liquid mixtures in tanks, pipelines, or vessels. Figure 38.1 illustrates a typical top-entering propeller/paddle mixer. This unit consists of an electric motor, a mounting bracket, an extended shaft, and one or more impeller(s) or pro-peller(s). Materials of construction range from bronze to stainless steel, which are selected based on the particular requirements of the application. 

The propeller/paddle mixer is also available in a sideentering configuration, which is shown in Figure 38.2. This configuration is typically used to agitate liquids... 

Add wood furnish (384 g, moisture content 6.02%) to the bowl of a rotary blade paddle mixer (such as a Kitchen-Aid KSM90) and agitate at the lowest speed setting. Add Mondur 541 (7.39 g, 1.9% w/w, a polymeric diphenylmethane diisocyanate of 31.5% NCO, Bayer) dropwise over a 5-min period using a disposable syringe. Continue blending for an additional 10 min and then transfer the blend to an 8 x 8 x 2 -in. metal form at the bottom of which is a metal plate which fits inside. The resin-coated furnish is evenly spread inside the form and another metal plate is placed on top. All parts of the form and plates are presprayed with mold release. The completed form assembly is placed into a hydraulic press (such as a model PW-22 manufactured by Pasadena Hydraulics) with platens heated at 350°F. The furnish is then pressed between the two form plates to a thickness of j in. Press controls are used to ensure consistency of board thickness. The assembly is heated for 4 min. before demolding the cured wood panel. 

Solid—solid blending can be accomplished by a number of techniques. Some of the most common include mechanical agitation which includes devices such as ribbon blenders, impellers, paddle mixers, orbiting screws, etc a rotary fixed container which includes twin-shell (Vee) and double-cone blenders and fluidization, in which air is used to blend some fine powders. 

Numerous equipment types can be used for agglomeration, including horizontal ribbon and vertical mixers, rotary drums, zig-zag mixers, and pan agglomerators. Horizontal ribbon mixers as shown in Fig. 36.41 are used primarily for dry mix formulating, where only limited agglomeration occurs. They are comprised of a U-shaped trough and a ribbon or paddle-type agitator. Liquids are sprayed onto the surface of the dry material and slowly dispersed into the mix. Mixer operations can be either batch or continuous. 

Figure 6.1 is an example of a rotational mixer. This type of setup is used to determine the optimum doses of chemicals. Varying amounts of chemicals are put into each of the six containers. The paddles inside each of the containers are then rotated at a predetermined speed by means of the motor sitting on top of the unit. This rotation agitates the water and mixes the chemicals with it. The paddles used in this setup are, in general, called impellers. A variety of impellers are used in practice. 

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