Hausner ratio

The Hausner ratio is a number that is correlated to the flowability of a powder or granular material. It is named after the engineer Henry H. Hausner (1900–1995).^[1]^[2]

The Hausner ratio is calculated by the formula

H={\frac {\rho _{T}}{\rho _{B}}}

where $\rho _{B}$ is the freely settled bulk density of the powder, and $\rho _{T}$ is the tapped bulk density of the powder. The Hausner ratio is not an absolute property of a material; its value can vary depending on the methodology used to determine it.

The Hausner ratio is used in a wide variety of industries ^[3]^[4]^[5]^[6]^[7] as an indication of the flowability of a powder.^[8] A Hausner ratio greater than 1.25 - 1.4^[9] is considered to be an indication of poor flowability. The Hausner ratio (H) is related to the Carr index (C), another indication of flowability, by the formula $H=100/(100-C)$ . Both the Hausner ratio and the Carr index are sometimes criticized, despite their relationships to flowability being established empirically, as not having a strong theoretical basis. Use of these measures persists, however, because the equipment required to perform the analysis is relatively cheap and the technique is easy to learn.

References

^ Beddow, J. K. 1995. "Professor Dr. Henry H. Hausner, 1900–1995." Particle & Particle Systems Characterization 12: 213. doi:10.1002/ppsc.19950120411.
^ Podczeck, Fridun & Brian E. Jones, eds. 2007. Pharmaceutical Capsules. London: Pharmaceutical Press, p. 111.
^ R.O. Grey and J.K. Beddow (1969) "On the Hausner Ratio and its relationship to some properties of metal powders" Powder Technology, Vol.2, No.6, pp 323-326.
^ Q. Li et al. (2004) "Interparticle van der Waals force in powder flowability and compactibility" International Journal of Pharmaceutics, Vol.280, Iss.1-2, pp 77-93.
^ C. Conesa et al. (2004) "Characterization of Flow Properties of Powder Coatings Used in the Automotive Industry" Kona, Vol.22, pp 94-106.
^ S.L. Rough, D.I. Wilson and D.W. York (2005) "Effect of solids formulation on the manufacture of high shear mixer agglomerates" Adv. Powder Technol., Vol.16, pp 145-169.
^ R.A. Garcia, R.A. Flores and C.E. Mazenko (2007) "Factors contributing to the poor bulk behavior of meat and bone meal and methods for improving these behaviors" Bioresource Technology, Vol.98, No.15, pp 2852-2858.
^ USP <1174> "Excipient General Information Chapter: Powder Flow
^ J. Cain (2002) "An alternative technique for determining ANSI/CEMA standard 550 flowability ratings for granular materials" Powder Hand. Proc, Vol.14, No.3, pp 218-220.

General Bibliography

Mark Gibson (2001). Pharmaceutical Preformulation and Formulation: A Practical Guide from Candidate Drug Selection to Commercial Dosage Form. Boca Raton: CRC Press. ISBN 1-57491-120-1.

This pharmacology-related article is a stub. You can help Wikipedia by expanding it.

[1] Beddow, J. K. 1995. "Professor Dr. Henry H. Hausner, 1900–1995." Particle & Particle Systems Characterization 12: 213. doi:10.1002/ppsc.19950120411.

[2] Podczeck, Fridun & Brian E. Jones, eds. 2007. Pharmaceutical Capsules. London: Pharmaceutical Press, p. 111.

[3] R.O. Grey and J.K. Beddow (1969) "On the Hausner Ratio and its relationship to some properties of metal powders" Powder Technology, Vol.2, No.6, pp 323-326.

[4] Q. Li et al. (2004) "Interparticle van der Waals force in powder flowability and compactibility" International Journal of Pharmaceutics, Vol.280, Iss.1-2, pp 77-93.

[5] C. Conesa et al. (2004) "Characterization of Flow Properties of Powder Coatings Used in the Automotive Industry" Kona, Vol.22, pp 94-106.

[6] S.L. Rough, D.I. Wilson and D.W. York (2005) "Effect of solids formulation on the manufacture of high shear mixer agglomerates" Adv. Powder Technol., Vol.16, pp 145-169.

[7] R.A. Garcia, R.A. Flores and C.E. Mazenko (2007) "Factors contributing to the poor bulk behavior of meat and bone meal and methods for improving these behaviors" Bioresource Technology, Vol.98, No.15, pp 2852-2858.

[8] USP <1174> "Excipient General Information Chapter: Powder Flow

[9] J. Cain (2002) "An alternative technique for determining ANSI/CEMA standard 550 flowability ratings for granular materials" Powder Hand. Proc, Vol.14, No.3, pp 218-220.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]