Vacuum assisted flow initiation in arching powders

Date

2016-04-07

Advisors

Journal Title

Journal ISSN

ISSN

0032-5910

Volume Title

Publisher

Elsevier

Type

Article

Peer reviewed

Yes

Abstract

The discharge of powders from hoppers usually takes place in open atmosphere. However, in powder pressing industries (e.g. manufacturing of pharmaceutical tablets, detergents, ceramics, powder metallurgy etc.) there are handling operations where powders are filled into closed cavities such as dies. During this process the air pressure is increased as powder is delivered into the die. At the same time typical tablet production equipment creates a suction effect. A critical orifice measurement apparatus was developed to study powder flow initiation from an arching state into an enclosure where the air pressure is reduced. It was shown that a very small reduction of pressure changed the critical orifice diameter significantly. Dimensional analysis was carried out to relate powder properties (particle size and density) and processing parameters (geometry of the system and differential pressure necessary to break the arch). A relationship was developed to calculate the pressure difference necessary to initiate powder flow. The relationship has two empirical parameters which are calibrated by performing simple experiments using the testing rig developed.

Description

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.

Keywords

Powder flow, Critical Orifice Diameter, Arching, Flow initiation, Model

Citation

Baserinia, R., Sinka, I.C. and Rajniak, P. (2016) Vacuum assisted flow initiation in arching powders. Powder Technology, 301, pp. 493-502

Rights

Research Institute

Institute of Engineering Sciences (IES)