The incubator is a piece of equipment that uses various means of heat transfer and environmental control, to obtain conditions under which specialized laboratory procedures can be carried out. In general, they have a system of electrical resistances that are controlled by devices such as thermostats or microprocessor controls. As for heat transfer systems, incubators basically use conduction and natural or forced convection. In incubators that work by thermal conduction, the set of electrical resistances directly transfers the heat to the walls of the chamber, where the samples are incubated. The resistors constitute a high temperature region, while the chamber is a lower temperature region. The transfer of thermal energy always occurs from the region of higher temperature to the region of lower temperature.
In incubators that work by thermal convection, the heat generated by the resistance system is transferred to a fluid –air– that circulates in the incubation chamber, transferring the heat to the samples; the efficiency of this process depends on the flow patterns of the process. In general, the air enters the incubator at the bottom and is heated in a compartment, from which it flows into the incubation chamber, following uniform flow patterns, to finally go outside through a duct located at the top. from the incubator.