In-line microwave warming apparatus

Microwave apparatus for warming a liquid having a temperature and flowing in a plastic conduit, said apparatus comprising:

• a rectangular waveguide member having a pair of opposite relatively broad walls and a pair of opposite narrower walls defining a microwave heating cavity;
• a disposable cartridge including an elongated plastic bobbin having a longitudinal axis and supporting a substantially parallel, uniform, side-by-side coiled array of said conduit in said cartridge;
• means in said apparatus for removably positioning said cartridge in said waveguide member so that said bobbin axis extends between the broad walls of the waveguide member at said heating cavity;
• means for applying microwave energy to said heating cavity and to said cartridge and the liquid flowing therethrough, said means for applying microwave energy producing a power output;
• non-invasive temperature monitoring means coupled to said cavity for measuring the temperature of the liquid flowing through said cartridge at said heating cavity, and
• control means electrically connected to said monitoring means and to said means for applying microwave energy, said control means being responsive to said measured temperature for controlling the power output of said means for applying microwave energy so as to maintain the temperature of the liquid flowing through said cartridge at a selected value.