Abstract: The steam or hot-water boiler provides a water heating apparatus that utilizes electromagnetic energy to produce steam or hot water. The invention consists of a boiler chamber, a source of electromagnetic energy, a resonant cavity, a fluid level control means, a temperature control means and a pressure control means. Water from the feedwater and/or condensate return line is heated in the resonant cavity as it circulates through the boiler chamber. The resonant cavity ensures that heat transfer occurs near or at the water surface in order to produce steam efficiently. Steam is then collected at the main header that leads it to conventional work stations.

Abstract: The microwave water heater provides a new and improved instantaneous hot water heating apparatus that utilizes electromagnetic energy to produce hot water. The invention consists of a source of electromagnetic energy, a resonant cavity, a fluid flow sensor means and a temperature sensor means. A flow sensor means controls the electromagnetic energy source as cold water is supplied from a conventional water supply system into the electrically isolated resonant cavity. Water is heated in the cavity as it moves through the cavity to the hot water outlet fixture. A thermostat may be provided in series with the flow sensor means to limit the output water temperature.