The cooler brings down the temperature of a hot-filled container to a tolerable level for labeling and additional handling. This is done with the use of cold utility or temperature-treated water showering down over slow-moving containers in mass flow by way of an open-top conveyor chain. The cooler employs both conductive and evaporative heat transfer to effectively reduce container temperature as required. Temperature holding zones can be utilized to affect the container as required by the process.
Warmers are used to elevate the temperature of cold-filled cans, minimizing surface condensation before cardboard packaging, as holding zones in coolers to allow the completion of a cooking process, and to temper cold glass before a hot product filling process in order to minimize container shock. Steam is the common medium in this application, although customized products utilizing alternative heating sources such as water or electrical radiators can be used in some applications.