摘要:
A silencer attenuating a noise from a noise source to be ventilated of this invention comprises a machine compartment with a one-dimensional duct configuration whose sectional dimension is sufficiently small in comparison with the wavelength of the noise to be attenuated, a compressor and/or other machinery disposed within the machine compartment, an opening for dissipation of heat as disposed in a wall of the machine compartment and opening in a direction generally perpendicular to the direction of advance of sound within the machine compartment, a vibration pickup for detecting the vibration of the machinery corresponding to the output noise of the machinery, and a control circuit for processing output signals from the vibration pickup to drive a sound generator such as a speaker. The sound generator outputs a controlling signal dependent on the machine noise to cancel the noise about to emerge from the machine compartment.
摘要:
A silencer for refrigerators includes a microphone for detecting noise produced by a compressor disposed in a machine compartment and converting the noise to an electrical signal, a signal converter converting the electrical signal generated by the microphone to a corresponding sound wave signal suitable for deadening the noise from the compressor by the effect of the sound wave interference, a speaker driven in response to the sound wave signal generated by the signal converter such that the sound is directed to the interior of the machine compartment of the refrigerator, a storage for previously storing data of noise patterns of the compressor in the abnormal condition of an evaporator as reference patterns, and a control comparing the electrical signal generated by the microphone with the data of the reference noise patterns stored in the storage, thereby determining as to whether or not the evaporator is abnormal.
摘要:
In a low noise refrigerator, a rotary compressor constituting a noise source is arranged within a machine chamber provided with an opening in one location, which chamber has a one-dimensional duct construction having a cross-sectional dimension which is small relative to trhe wavelength of the noise which is to be reduced. A vibration pick-up being located in the vicinity of the rotary compressor. The vibration pick-up detects compressor vibrations which correlate to the compressor noise, in the tangential direction of the compressor. There is provided a control circuit that processes the output signal of the vibration pick-up. In the machine chamber, a sound generator is driven by the output signal of the control circuit to generate a control sound, so that the compressor noise which tries to issue from the opening is canceled by the control sound.
摘要:
A refrigerator with a noise attenuating function includes a cabinet having storage and machine compartments, a compressor disposed in the machine compartment, a noise detector disposed in the machine compartment for detecting noise produced from driving of the compressor and converting the noise to an electrical signal, an operational unit for converting the electrical signal to an acoustic signal for an active noise control, a cancellation sound producer producing a sound of opposite phase with the noise based on the acoustic signal so that the noise is attenuated, a noise attenuation monitoring sound receiver for monitoring the noise attenuating effect of the cancellation sound producer, an adaptive control circuit changing an operational factor of the operational unit by a predetermined amount when the monitoring result of the noise attenuation monitoring sound receiver is out of a predetermined tolerance, the adaptive control circuit being adapted to continuously perform the operation of changing the operational factor until the monitoring result comes into the tolerance, and a connecting member for integrally connecting the cancellation sound producer and the noise attenuation monitoring sound receiver.
摘要:
A silencer for refrigerators includes a microphone receiving sound from a motor-compressor mounted in a machine compartment to thereby generate an electrical signal in accordance with the received sound, a signal converter converting the electrical signal generated by the noise receiver to an electrical signal for producing sound deadening the sound from the motor-compressor by the effect of sound wave interference, and a speaker for producing the sound based on the signal converted by the signal converter so that the sound interferes with the sound from the motor-compressor. The machine compartment is closed with a ventilating opening left opened. One of dimensions of the machine compartment in the three-dimensional directions is set at a value larger than those of the others so that a standing wave of the sound from the motor-compressor in the machine compartment is composed only in a primary mode in a low frequency range below 700 Hz. The ventilating opening is formed into a generally rectangular shape extending in the direction perpendicular to the direction that the standing wave travels.
摘要:
In a low noise refrigerator, a compressor constituting a noise source is arranged within a machine chamber provided with an opening in one location, which chamber has a one-dimensional duct construction in which its cross-sectional dimension is small relative to the wavelength of the noise which is to be reduced. A vibration pick-up is located in the vicinity of the compressor. The vibration pick-up detects compressor vibrations which correlate to the compressor noise of the compressor. There is provided a control circuit that processes the output signal of the vibration pick-up. In the machine chamber, a sound generator is driven by the output signal of the control circuit to generate a control sound, so that the compressor noise which tries to issue from the opening is canceled by the control sound.
摘要:
A silencer for deadening noise produced with drive of a motor-compressor disposed in a machine compartment of a refrigerator includes a data storage for previously storing sound wave data for every starting condition of the compressor, the sound wave data corresponding to sound waves produced by the compressor during a starting period thereof, the sound wave data being sound wave signals suitable for reducing sound from the compressor by the effect of sound wave interference, a control for determining the starting condition at the starting of the compressor, the control further reading out, from the data storage, the sound wave data corresponding to the determined starting condition, during the starting of the compressor, and a sound producer driven in response to the sound wave data read out from the data storage in the form of an electrical signal, thereby producing sound waves, the sound producer being disposed so that sound is directed to the interior of the machine compartment.
摘要:
Disclosed is a tape for polishing the surface of a substrate of a magnetic recording medium, and a thin-fineness filament obtained by dissolving a dissolving component of a dissolution-decomposition type composite yarn consisting of a nylon component and the dissolving component is used as piles of a flocked cloth, warps of a fabric, and webs of a nonwoven fabric.The polishing tape of the present invention can noticeably improve the surface roughness of the polished substrate.
摘要:
A sheath-core composite conductive fiber having a sheath component made of a fiber-forming polymer containing conductive carbon black, is characterized in that, with respect to an inscribed circle of a core component and an inscribed circle of a sheath component in a cross section of the fiber, a radius (R) of the inscribed circle of the sheath component and a distance (r) between the centers of two inscribed circles satisfy a specific relationship, and a sheath-core composite conductive fiber having: a core component made of a polyester containing ethylene terephthalate as a main component, and a sheath component made of a mixture of a copolyester wherein ethylene terephthalate accounts for 10 to 90 mol % of constituent units thereof and carbon black. The conductive fiber can be used alone or in combination with other fibers in various applications, e.g., special working clothes such as dust-free clothes and interiors such as carpets.
摘要:
A method of constructing a top slab to provide a containment roof over a nuclear-power generating building, in particular, a method for utilizing overhead spaces bounded by a wall of the containment building and a shielding wall of the pressure vessel building, wherein the sequential steps involve; erecting a plurality of paired support columns on tops of the wall and of the shielding wall; building upper structural components across said paired support columns; installing a slab liner equipped with slab anchors beneath said lower structural components by suitable joining means; constucting a reinforcing network above said lower structural components; encasing said lower structural components and said reinforcing network; and pouring concrete over the slab liner to a suitable depth.