Provided herein is a system for reducing the overall noise output of equipment used in the hydraulic fracturing of oil and gas wells, by providing a noise-reducing enclosure and/or radiator which substantially reduce the level of noise that reaches the environment during normal operation.

A consumer appliance is provided herein. The consumer appliance may include a cabinet, an exterior panel, an electromechanical driver, an electromechanical receiver, and a controller. The cabinet may define an internal chamber. The exterior panel may be mounted to the cabinet. The electromechanical driver may be fixed to the exterior panel to generate a soundwave therefrom. The electromechanical receiver may be mounted within the cabinet. The controller may be configured to initiate a noise canceling operation. The noise canceling operation may include receiving a noise input signal at the electromechanical receiver and initiating an anti-noise wave at the electromechanical driver through the exterior panel based on the received noise input signal.

A system including a rig site with at least one pollution control system located on the rig site. The pollution control system is configured to modify an output of light, noise, or vibrations from the rig site to an environment surrounding the rig site. Additionally, the pollution control system may include at least one active noise cancellation device, at least one active vibration cancellation device, and/or at least one active light control system to modify the light, noise, or vibrations.

A method for operating a centrifugal separator associated with a prime mover and/or a working machine. The centrifugal separator comprises at least one rotatably mounted rotor that can be rotated at a variable speed via a drive controlled by a control unit. The method is characterized in that the speed of the rotor is controlled according to the sound emissions of the prime mover and/or according to the sound emissions of the working machine.

The invention relates to a laboratory mill comprising at least one counter-vibration device (27) which has at least one control unit (29a) for providing a counter-vibration signal (29b) and at least one controllable vibration generation unit (29) for converting the counter-vibration signal (29b) into counter-vibrations (30), wherein the vibration-generation unit (29) counteracts a device- and/or housing part (31) of the laboratory mill (1) and the counter-vibrations (30) lead to an active reduction in the vibrations of the device- and/or housing part (31) and/or an at least partial suppression of noise-inducing vibrations of the device- and/or housing part (31), by means of destructive interference.

An acoustic panel comprises a face sheet comprising a plurality of openings; a back sheet opposite to the face sheet; and an intermediate layer comprising a plurality of cells each comprising a cavity and a plurality of walls extending between the face sheet and the back sheet and surrounding the cavity. The plurality of walls can comprise at least one and possibly a plurality of slots for drainage. A method for making the acoustic panel is also described.

A rotor blade with a leading edge and a trailing edge is provided, wherein the rotor blade is for being exposed to a fluid flowing substantially from the leading edge to the trailing edge, the rotor blade includes at least three sensors designed for detecting flow characteristics of the fluid and providing respective sensor signals, wherein the sensors are arranged with a non-uniform spacing, and the rotor blade further includes at least one actuator for producing an anti-noise signal based on a sensor signal, the sensors and the actuator are arranged at the surface of the rotor blade, and the actuator is arranged and prepared such that flow-induced edge noise of the rotor blade, which is generated by the fluid, is at least partly cancelled out by the anti-noise signal. A method for creating such rotor blade and a related wind turbine is also provided.

A food waste disposer system (300) has active noise control of food waste disposer noise that is generated by the food waste disposer (302) when a motor of the food waste disposer (302) is running. The food waste disposer (302) has a food conveying section that conveys food waste to a grinding section. The grinding section has a rotatable shredder plate that is rotated by a motor of a motor section. Active noise sound waves (310) are radiated into an area (313) where the food waste disposer noise is to be controlled at an amplitude and frequency to at least cancel or mask the food waste disposer noise.

There are provided a control signal generation unit 120 that generates a control signal on the basis of a cosine wave signal and a sine wave signal whose frequencies are a control frequency identified according to a vibration noise source, and a correction value update unit that updates a correction value to a value for decreasing signal power of an error signal on the basis of a relationship between increase and decrease of the signal power of the error signal obtained from remaining vibration noise that remains after interference sound that is generated on the basis of the control signal and propagates through a secondary route interferes with vibration noise generated from the vibration noise source and increase and decrease of the correction value used for correction of the control frequency.

A method to suppress noise emanating from an electrical power generator including the steps of: receiving sound emanating from the electrical power generator, wherein the sound is received in a duct for cooling air having passed through the generator; analyzing the received sound and, based on the analysis, generating a sound signal which represents a destructive sound to the received sound, and broadcasting a destructive sound into the duct, wherein the destructive sound corresponds to the sound signal.