Abstract: The inner-surfaces of heat exchanger tubing is cleansed with a sulfamic acid aqueous mixture and then subjected to a purplish-colored aqueous solution of potassium permangenate adapted to seep through to and become visually discernible at the heat exchanger tubing outer-surface to thusly visually indicate breach-faulted heat exchanger tubing. Any thusly inspected non-breach heat exchanger is purged with an oxalic acid aqueous solution and retained as acceptable for future re-use. The breach detecting method is generally applicable to all heat exchangers of the heat-conductive metallic tubing type, and, inter alia, specificaly applicable to dairy plate heat exchangers having metallic tubings.

Abstract: For vial samples of milk collected along a route of dairy farms, a sample vials tray is provided of foldable mode that can be readily accommodated within the limited-volume ice chest of the route agent's truck. At the agent's milk processing plant, the same tray, and with the sample vials undisturbed therein, can be employed in the non-folded and latched condition required for automated laboratory analysis of milk samples contained in the tray-housed vials. A multi-prongs type holder holds each vial in a secure condition during the vehicular journey from dairy farm to milk processing plant. The foldable tray utilizes a special hinge that is relegated to a non-obtrusive location that does not interfere with the tray's usage in concert with automated laboratory analytical equipment.