Below is a list of Heat Exchangers manufacturers from Duquesne, Pennsylvania. Heat exchangers are heat transferring devices used to move heat from one gaseous or liquid substance to another for the purpose of either heating or cooling a substance for another process. Constructed with thermally conductive plates or tubes, heat exchangers are used to transfer heat from water to water, air to air, water to air or steam to other liquids – such as lubrication oil.