Abstract: A substantially metal-free exhaust subsystem includes an exterior housing formed of polymer; and a pipe formed of a layered fibers formed at least partially of glass, and bound by an inorganic binder. The fibers may be glass or ceramic, and may define micro-pores on the interior of the pipe that aid in absorbing acoustic energy, and thereby attenuating exhaust noise.

Abstract: A pumped-storage power plant may include a working cylinder partially submerged in a working fluid reservoir having an upper fluid compartment above a fluid level of the working fluid reservoir and a lower fluid compartment below the fluid level, a buoyant piston movably guided in the direction of gravity relative to the working cylinder and which seals off the upper fluid compartment such that a gravitationally induced exchange of fluid between the upper and the lower fluid compartment is prevented. The plant may operate in an energy charging mode where working fluid is introduced into the upper fluid compartment so that the buoyant piston is submerged in the lower fluid compartment, and an energy delivery mode where upper fluid is pressed out of the upper fluid compartment and/or a fluid column of the upper fluid built up during the energy charging mode is discharged from the upper fluid compartment.

Abstract: A substantially metal-free exhaust subsystem includes an exterior housing formed of polymer; and a pipe formed of a layered fibers formed at least partially of glass, and bound by an inorganic binder. The fibers may be glass or ceramic, and may define micro-pores on the interior of the pipe that aid in absorbing acoustic energy, and thereby attenuating exhaust noise.

Abstract: An absorption muffler includes a metallic exhaust pipe including a plurality of perforations, a polymeric housing carried by the exhaust pipe and enclosing the plurality of perforations, and including axially opposed ends. Thermal insulation is carried radially between the exhaust pipe and the polymeric housing and axially between the axially opposed ends inclusive thereof. Acoustic insulation is carried between the thermal insulation and the polymeric housing.

Abstract: An absorption muffler includes a metallic exhaust pipe including a plurality of perforations, a polymeric housing carried by the exhaust pipe and enclosing the plurality of perforations, and including axially opposed ends. Thermal insulation is carried radially between the exhaust pipe and the polymeric housing and axially between the axially opposed ends inclusive thereof. Acoustic insulation is carried between the thermal insulation and the polymeric housing.

Abstract: The invention relates to a silencer (1) for noise-laden gas pipes, especially for a suction pipe and/or an exhaust pipe of an internal combustion engine, comprising an outer pipe (2) with an inlet side (3) and an outlet side (4), a plurality of diaphragm rings (9, 9′, 9″, ′″, 9″″) each with an outer surface connected (5) to the inner surface of the outer pipe (2), at least one insert (6) with an outer surface connected (7) to the inner surface of the outer pipe (2) and/or the diaphragm rings (9, 9′, 9″, 9′″, 9″″) and with a plurality of openings (8) which are closed on one side. Said insert (6) forms sub-pipes for the gas flow in the silencer, and the openings (8), which are closed on one side, open into the sub-pipes, the depth thereof being /4 in relation to the wavelength of a frequency to be silenced.

Abstract: To dampen a sound created in an electrical tool or appliance having an air passage through which air is being forced, a sound damper is placed in the air passage. Preferably, a filter is provided upstream of the sound damper to prevent suspended particles, fibers, fumes and the like from entering the sound damper.

Abstract: To dampen a sound created in an electrical tool or appliance having an air passage through which air is being forced, a sound damper is placed in the air passage. Preferably, a filter is provided upstream of the sound damper to prevent suspended particles, fibers, fumes and the like from entering the sound damper.

Abstract: The broadband surface-like absorber of the invention is used, in particular, for absorbing troublesome airborne noise in the acoustic frequency range. The broadband surface-like absorber, which operates on the Helmholtz resonator principle, is distinguished by a checkerwork of irregular construction, the webs of which are aligned with their narrow sides perpendicular to the principal surface of the perforated plate and the side edges of which are connected in a sound-pressure-resistant and fluidtight manner on the sound side to the rear side of the perforated plate and, on the rear side, to an extended-area cavity boundary aligned with the same orientation as the perforated plate to form differently tuned chamber resonators.