A sound level reducing apparatus and method for reducing the outdoor sound level produced by a high efficiency gas furnace. The apparatus comprising a muffler having an internal length determined by an identified target pure tone frequency producing an undesirable sound level. The internal length may be optimized to reduce the sound level across a range of operational frequencies.

An air intake coupling has at least one noise suppression hole formed therein. A gas-air mixer elbow is fluidly coupled to the air intake coupling. A burner box assembly is fluidly coupled to the gas-air mixer elbow via a gas-air plenum box. A heat-exchange tube has a first end that is fluidly coupled to the burner box assembly. A fan is fluidly coupled to a second end of the heat-exchange tube via a cold-end header box.

The invention concerns a damper arrangement for reducing combustion-chamber pulsation arising inside a gas turbine, wherein the gas turbine includes at least one compressor, a primary combustor which is connected downstream to the compressor, and the hot gases of the primary combustor are admitted at least to an intermediate turbine or directly or indirectly to a secondary combustor. The hot gases of the secondary combustor are admitted to a further turbine or directly or indirectly to an energy recovery, wherein at least one combustor is arranged in a can-architecture. At least one combustor liner includes air passages, wherein at least one of the air passages is formed as a damper neck. The damper neck being actively connected to a damper volume, and the damper volume is part of a connecting duct extending between a compressor air plenum and the combustor.

A gas burner system has a gas burner with a conduit through which an air-gas mixture is conducted; a variable-speed forced-air device that forces air through the conduit; a control valve that controls a supply of gas for mixture with the air to thereby form the air-gas mixture; and an electrode configured to ignite the air-gas mixture so as to produce a flame. The electrode is further configured to measure a flame ionization current associated with the flame. A controller is configured to actively control the variable-speed forced-air device based on the flame ionization current measured by the electrode so as to automatically avoid a flame harmonic mode of the gas burner. Corresponding methods are provided.

A soundproofing device for a transmission according to the present disclosure is provided to transmit the power of one or more prime movers (for example, internal combustion engine and electric motor). The soundproofing device includes a Helmholtz resonator including: a wall that forms a Helmholtz resonance chamber; and an opening formed in the wall so as to cause the Helmholtz resonance chamber to communicate with the outside of the Helmholtz resonance chamber. The wall includes a transmission case that accommodates the transmission and a housing of a component mounted on the transmission (for example, PCU housing). The Helmholtz resonance chamber is formed between the transmission case and the housing.

An acoustic liner includes a first face sheet, a second face sheet spaced from the first face sheet, and a plurality of sidewalls extending between the first face sheet and the second face sheet. The plurality of sidewalls defines a plurality of cells. Each cell of the plurality of cells defines a cavity between the first face sheet and the second face sheet. A bulk absorber is disposed within at least one cell of the plurality of cells. The bulk absorber further defines the cavity of the at least one cell of the plurality of cells. The first face sheet defines a plurality of apertures extending through a thickness of the first face sheet. Each aperture of the plurality of apertures is aligned with a respective cell of the plurality of cells.

A combustion tube assembly of a water heater includes a combustion tube having an open end, a closed end, and an outflow opening located between the open end and the closed end. A cavity of the combustion tube provides a chamber for a combustion of a water heater fuel that produces an exhaust gas that flows down toward the closed end. The combustion tube assembly further includes a diverter structure positioned inside the combustion tube to divert the exhaust gas such that the exhaust gas flows toward the closed end on a first side of the diverter structure and flows from the first side of the diverter structure to the second side of the diverter structure through a flow opening proximal to the closed end. The outflow opening provides an outlet for the exhaust gas that flows to the second side of the diverter structure to exit the combustion tube.

A combustion tube assembly of a water heater includes a combustion tube having an open end, a closed end, and an outflow opening between the open end and the closed end. A cavity of the combustion tube provides a chamber for a combustion of a water heater fuel, where the outflow opening provides an outlet for an exhaust gas resulting from the combustion of the water heater fuel to exit the combustion tube. The combustion tube assembly further includes a spring positioned in the cavity of the combustion tube at the closed end of the combustion tube.

In one aspect there is provided a gas flare comprising a hollow cylindrical member having a bottom end, a top end, a discharge end at said top end, and defining an interior volume having a mixing region. The gas flare further comprises a gas inlet to receive waste fluids, an air inlet to receive and direct air into the interior volume, and an internal riser having an outlet. The mixing region is located above the air inlet and below the discharge end. The internal riser fluidly and sealably connects to the gas inlet and directs all waste fluids from the gas inlet, out through the outlet, into the mixing region.

In one aspect there is provided a gas flare comprising a hollow cylindrical member having a bottom end, a top end, a discharge end at said top end, and defining an interior volume having a mixing region. The gas flare further comprises a gas inlet to receive waste fluids, an air inlet to receive and direct air into the interior volume, and an internal riser having an outlet. The mixing region is located above the air inlet and below the discharge end. The internal riser fluidly and sealably connects to the gas inlet and directs all waste fluids from the gas inlet, out through the outlet, into the mixing region.