Figure 1: Schematic of the three possible orientations inside the reciprocating cage showing the placement of experimental can with its longer axis: a horizontally along the reciprocation axis (HA), b horizontally perpendicular to reciprocation axis (HP), and c vertical (V)
Article from Food and Bioprocess Technology 8:1405-1418
Anubhav Pratap Singh, Hosahalli S Ramaswamy
Abstract
The objective of this work was to study the effect of container orientation on heat transfer during reciprocation agitation thermal processing of cans filled with liquid particulate mixtures. A vertical steam retort, retrofitted with a mechanism to provide horizontal reciprocation of containers, was used in this study. Cans of size 307 × 409, filled with 30 % (v/v) Nylon particles in a Newtonian fluid (100 % glycerin), were placed inside the reciprocating cage with longer axis in one of the three possible orientations viz. horizontal along axis of reciprocation (HA), horizontal perpendicular to axis of reciprocation (HP), or vertical (V). Reciprocation frequency (1–4 Hz) and amplitude (5–25 cm), and container headspace (2–12 mm) were varied according to a full factorial experimental design, and heat transfer coefficients and process times associated with each orientation were calculated. Additional experiments were also carried out in still mode to study the effect of container orientation in static processing mode. Results showed that for the static mode, HA and HP provided more rapid heating than V. For agitation processing, HA provided more rapid heat transfer followed by HP and then V, respectively. Reciprocation frequency and amplitude affected the heat transfer significantly (p < 0.05) in all orientations, while headspace was significant only for HA. An agitation intensity (AI) parameter was defined based on reciprocation frequency and amplitude. An AI value of 3.0 g was found sufficient for HA cans, while HP and V cans required a higher AI of 6.0 g for optimum heat transfer. This study could be used in designing of reciprocation thermal processes with optimal heat transfer delivery.