Used in food processing and process control facilities, double walled, or jacketed funnels are mainly used for temperature control. Double walled funnels are made using two stainless steel funnels, nested together to form a high quality, complete assembly.  Temperature control is monitored by running cool fluids through the jacket to keep the contents cool, or running hot fluids through the assembly to keep the contents hot. The nested funnels act as a double boiler which helps keep viscous products flowing, or to keep the product at at a set temperature.