Flow aid

Flow Aids. Flow aids are devices used to assist in discharging materials from a bin or other storage container. The best use of such a device is when gravity alone is insufficient or impractical to provide rehable discharge. However, in many instances, flow aid devices are ovemsed in appHcations in which they are either uimecessary or create new problems. 

Charge the OH functional urethane water dispersion prepared in Example 8 (200 g, 0.1603 eq. OH) to a suitable container. Vigorously stir the dispersion with a mechanical stirrer and slowly add the 18.8% NCO water-dispersible polyisocyanate described above (40.0 g, 0.1791 eq.). This will give an NCO-OH equivalent ratio (index) of 1.12. To this mixture, add Silwet L-77 (a flow aid from OSi Specialties) and thoroughly mix. Use a draw-down bar to make 6-mil (0.006-in.) wet-thickness films on glass plates and 5-mil (0.005-in.) films on Bonderite-treated steel panels (Bonderite is from Henkel). Condition the resultant films at 72°F and 50% RH for 2-3 weeks before evaluating. For the finished... 

This is consistent with the flow-aided diffusion condition postulated for this region interpreted as an increase in the effective initiator concentration as (NRg)g increases. The increased initiator concentration causes the reduction in molecular weight (22). Values of (NRg)e greater than 4000 show an increasing weight as (NRe)e increases. This cannot be explained by the decrease in effective soap concentration because this would cause a further... 

Tardos, G. I., Garcia, J., Ahart, R., and Ratuiste, F., How and Why Some Flow Aids Promote Bulk Powder Flow, AIChE Symp. Senes, 296(89) 18-34 (1993)... 

Brink, A. E., Turner, S. R. and Keep, G. T Poly(alkylene ether)s as plasticizers and flow aids in poly(l,4-cyclohexanedimethylene terephthalate) resins, US Patent 5 965 648, 1999. 

Movement of the resin to the shaping apparatus through application of heat and/or pressure and other flow aiding processes... 

Figure S-4 Velocity profiles in a tube in plug-flow aid in laminar flow reactors.

Flow aids can generally be divided into three categories mechanical, eg, those that rely on vibration or agitation of the material, such as vibrating dischargers, external vibrators, rotating arms, vibrating panels, etc introduction of air, eg, air cannons, air slides, or air nozzles and chemical, eg, fumed silica. Some flow aids rely on a combination of these types. 

Steady Mechanical Displacement Flow Aided by Drag, 159... 

STEADY MECHANICAL DISPLACEMENT FLOW AIDED BY DRAG 159... 

Due to their disperse character and small particle size, silicas are used as flow aids, i.e. they are used to improve the flow behaviour of other materials. The adsorption of the fine silica particles on other type powdered compounds reduces interparticle interactions. Particle adhesion, electrostatic adhesion, Van Der Waals forces and liquid bridge formation is reduced or avoided.33 This allows free-flowing behaviour of strongly interacting or irregularly shaped powdered materials. 

Formulation design is based on the physical, chemical, and biopharmaceutical properties of a drug substance. A formulation for direct compression is composed of active pharmaceutical ingredients and other inactive ingredients such as fillers, binders, dis-integrants, flow aids, and lubricants. Simplicity is the basis of good formulation design. Minimally, a direct compression tablet formulation must meet requirements for manufacturability, uniformity of dose, physical and chemical stability, appropriate dmg release profiles, and bioavailability. In addition, the formulation must meet many quality standards and special requirements to ensure the efficacy and safety of the product. 

Mold design is a decisive factor for the molding success such as dimensioning and location of the sprue gates, dimensioning of shear edges, flow aids, cooling and ejector techniques, etc. 

Troxel, T.G. Flow aids—what to use and when to use them. Powder/Bulk Solids Adv. Dry Process 2000, 12-16. 

Spray-dried lactose is widely used as a binder, filler-binder, and flow aid in direct compression tableting. 

Erratic flow is the result of obstructions alternating between an arch and a rathole. A rathole may collapse due to an external force, such as vibrations created by surrounding equipment, or a flow-aid device such as an external vibrator. While some material is likely to discharge, falling material often impacts over the outlet and forms an arch. An arch may break due to a similar external force, and material flow may resume until the flow channel is emptied and a rathole is formed again. 

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