Abstract: A variable orifice gas modulating valve for use with an atmospheric Bunsen-type burner is disclosed. The variable orifice valve discharges a jet of fuel directly into the burner mixing tube and modulates the gas flow to the burner by changing the cross-sectional area of the gas jet. This is accomplished by a thin moveable sheet interposed between a valve body and a cap, through which pass the upstream and downstream portions of a short gas discharge passageway. The sheet has a hole which is positioned relative to the axis of the gas discharge passageway so as to produce a discharge orifice of variable size. The gas jet has the same velocity at all inputs, and flow rate variation is manifested by variation in the jet cross-sectional flow area.

Abstract: A semi-instantaneous water heater is disclosed. The water heater generates domestic hot water by transferring heat from the circulating fluid of a modulating boiler. It is particularly suited for use in a combination system, which provides both space and water heating. The semi-instantaneous design incorporates a small cylindrical tank containing stored hot water and an immersed heat exchanger. The heat exchanger is a helical coil disposed in the annular space between two metal sheets that have been rolled into cylinders. The coil conveys heated fluid from the boiler. Heat from the coil is transferred to the water, which is admitted to the tank via the helical passageway formed by the two sheets and the inter-coil space of the helix. The heat exchanger effectively transfers heat by forced convection at a high rate when required by a high flowrate of water. Its disposition in the tank also permits good heat transfer by free convection to quiescent water in the tank when this heating mode is required.

Abstract: A gas modulating valve for use with a gas burner is disclosed. Two variations of the valve are disclosed: the direct-discharge variation discharges a gas jet directly into the mixing tube of a gas burner, and the in-line variation meters the gas flow from the supply line to a gas manifold, which in turn terminates in one or more fixed orifices which discharge to the burner mixing tube or tubes. With respect to the moving parts, the two variations are identical. In both variations, the modulation of the gas flow is achieved by a thin moveable slide sandwiched in a planar space between two fixed valve body members, through which pass the upstream and downstream portions of a short gas discharge passageway. The slide has a hole which is positioned relative to the axis of the gas discharge passageway so as to produce a discharge orifice of variable size. The valve is sealed against leakage by face seals effected with o-rings. The valve actuator is a stepper motor which is controlled by an electronic controller.