What are the flow properties of powder?
What are the flow properties of powder?
Four commonly reported methods for testing powder flow are (1) angle of repose, (2) compressibility index or Hausner ratio, (3) flow rate through an orifice, and (4) shear cell. In addition, numerous variations of each of these basic methods are available.
What is the importance of determining the flow properties of powders and granules?
The knowledge of their flow properties is of critical significance in operations such as blending, tablet compression, capsule filling, transportation, and in scale-up operations.
How flow properties of powders are measured?
Some of the most commonly applied methods to measure the flow of powders include: density indices, such as the Carr index and Hausner ratio, powder avalanching, the angle of repose (AOR), flow through an orifice, powder rheometry and shear cell testing.
What are the factors that affect the flow properties of powder?
Moisture content, temperature, particle size, and time of storage at rest can have a tremendous impact on your material’s flow properties. How your material flows is a function of its cohesive properties.
Which improves flow property of granules?
Flat and elongated particles give high porosity and low flow property. In contrast, high density and low porosity provide good flow property. Powder flow properties can be improved by processing the granules in spherical shape.
What is flow rate of a powder?
The flow rate of a powder is a property that indicates the friction among the constituent particles [31, 35] ; hence, particle size and morphology are determinant factors The angle of repose is a relative measurement of the friction and cohesion among particles, so the particle size of the material will influence its …
Which one improve the flow properties of granules?
Smooth surface of particle increases the flow properties, however the rough surface is the reason of poor flowability due to friction. Flat and elongated particles give high porosity and low flow property.
Which parameters are used to measure flow properties of powder?
Powders flow properties are measured using a number of parameters such as, angle of repose, compressibility index (Carr’s index) and Hausner ratio.
How do you increase powder flow?
Granulators. Granulation is a common technique to help to improve product flow and achieve mass flow. Powder granulation can reduce inconsistency in particle size, reduce “fines” (very small particles), control dust, and reduce the tendency of powders to segregate.
What is added to powder to improve ability of flow?
Glidants are usually added prior to compression to improve the powder flow properties of the materials by reducing friction between particles.
Which test can predict the flow properties of powders?
Avalanche test. Unlike other tests, this method does not put the powder under stress, so it is best used for powders that are free flowing. During manufacturing, this free-flowing condition occurs during blending, conveying, tableting, capsulating, and packaging.
What makes powder free flowing?
Powders that do not pour easily are difficult to use or process. Adding SIPERNAT® specialty silica or AEROSIL® fumed silica from Evonik makes powders especially pourable, free flowing and therefore easy to dose. This is known as the free flow effect.
Does granulation improve powder flow?
Granulation is a common technique to help to improve product flow and achieve mass flow. Powder granulation can reduce inconsistency in particle size, reduce “fines” (very small particles), control dust, and reduce the tendency of powders to segregate.
How can I make my powder flow better?
The most traditional approach to increase a powder’s flowability is to increase the size of the particles that make up a powders bulk, allowing the forces encouraging movement (such as gravity or pressurised air) to outweigh the forces of cohesion, thereby, allowing the powder particles to flow.
How do you calculate flow property?
PROCEDURE
- Determination of bulk density and tap density. 10gm of powder sample was weight accurately.
- Determination of carr’s index and housner’s ratio:- Carr’s Index= {(Tapped Density –Bulk Dencity) /Tapped Density } ×100.
- Determination of angle of repose:-
- Determination of flow rate.
What is used to improve flow properties?
The effects on flow and impedance of magnesium stearate (MgSt), colloidal silica (SiO2), and talc were examined. These three additives are widely known to improve flow properties of many for- mulations and are commonly used in a majority of oral dose formulations.
How does density affect powder flow?
It is for this reason that powders containing large particles, or consisting of material that has high density, tend to flow better when loosely packed—each particle’s individual mass and, therefore, the gravitational force acting on it, is high.
Which one improve the flow property of granules?
How can we improve powder flow?
How can I improve my powder flow?
What are the flow properties of powders?
Few such flow properties and techniques are powder spreadability, dynamic and static angle of repose, packing, flowability, and electrostatic charge. Flow properties of powders are basically mechanical properties. The behaviors of bulk powders are very much similar to the non-Newtonian fluids due to its plastic flow and dilatancy.
How to improve the flow properties of granules?
Flat and elongated particles give high porosity and low flow property. In contrast, high density and low porosity provide good flow property. Powder flow properties can be improved by processing the granules in spherical shape.
What are the objectives of granulation in powder engineering?
The main objective of granulation is to improve the undesirable powder characteristics of raw materials (poor powder flow, fluffiness, segregation, etc.); therefore, the specific needs first must be identified. Granulation properties after the process are likely different, depending on the target of the process.
What are the common powder flow problems in powder industry?
A number of problems can develop as powder flows through equipment such as bins, chutes, and press hoppers. If the powder is cohesive, an arch or rathole may form, resulting in “no flow” or erratic flow. In addition, flooding or uncontrolled discharge may occur if a rathole spontaneously collapses.
