Abstract: A silencer for a vacuum cleaner is provided and includes at least one hermetic expansion chamber mounted in an exhaust channel of the vacuum cleaner and allowing an exhaust airflow from the vacuum cleaner to pass through. The expansion chamber at its two sides has an inlet and an outlet connected to the exhaust channel. A silencing board is mounted in the expansion chamber, separating the inlet from the outlet. Pores are distributed throughout in the silencing board. The silencer integrates several different silencing structures together, and, when mounted to the exhaust port of the vacuum cleaner, can considerably diminish the noise generated by the vacuum cleaner in operation.

Abstract: By arranging a power device or devices on the outer face of a partition wall such as a linking portion (flange portion) constituting a flow passage between the exhaust port of a centrifugal fan and a motor, the power device or devices can be efficiently cooled without disturbing the air flow in an air channel within a case and without increasing in pressure loss of the air channel. Moreover, the power device or devices are not affected by heat from the motor since they are positioned farther upstream than the motor, in the air flow from the centrifugal fan.

Abstract: In an arrangement comprising a motor/pump unit and a sound-deadening cover, the sound-deadening cover absorbs the airborne noise emitted by the motor/pump unit. On the other hand, the sound-deadening cover acts like the diaphragm of a loudspeaker for the structureborne noise emanating from the motor/pump unit. In order to absorb the structureborne noise as well, the sound-deadening cover is constructed as a sound-deadening hood, and is placed over the motor/pump unit in the operating condition, without touching it. During transportation, the sound-deadening hood and the motor/pump unit are supported on one another. The arrangement is used to absorb sound from units comprising a pump and a motor driving the latter.

Abstract: An upright vacuum cleaner having a muffler system is disclosed. The upright vacuum cleaner includes a carpet engaging nozzle base and an upper housing pivotally connected to the nozzle base. The upright vacuum cleaner further includes a dirt cup removably secured to the upper housing and having an inlet in fluid communication with the nozzle base and an exit. The upright vacuum cleaner yet further includes a motor/fan unit fluidly connected to the dirt cup exit and positioned proximate to a pivot axis between the base and the upper housing. The upright vacuum cleaner still further includes an expansion chamber defined at least partially by the upper housing and a vertical wall of the dirt cup when the dirt cup is in an operational position relative to the housing. The motor fan units draws air from the dirt cup exit and directs air toward the expansion chamber. A method of operating an upright vacuum cleaner is also disclosed.

Abstract: An improved vacuum cleaner has an acoustic dampening mechanism to substantially reduce the noise level generated from a suction unit of the vacuum cleaner while it is sufficiently cooled. Noise that radiates from the motor is continually sucked back into the motor and in effect, the noise is bent by using suction so that the noise is muffled by being pulled back into the motor.

Abstract: Contoured intakes and fan housing assemblies for floor care machines are disclosed. In one embodiment, a contoured intake includes a contoured duct having a passage therethrough. The passage has a cross-sectional area progression that smoothly varies between a first cross-sectional area and a second cross-sectional area. Turbulence within the intake passage may be reduced or inhibited, and noise generated by the airstream within the intake passage may be reduced. In another embodiment, the contoured duct may include a bellmouth substantially surrounding the first open end that may inhibit the separation of the airstream within the intake passage. In a further embodiment, an airflow propulsion device for a floor care machine may include a motor having a drive shaft, a fan operatively coupled to the drive shaft, and a fan housing disposed about the fan and having a transition passage proximate the radially-outward ends of the vanes of the fan.

Abstract: The present invention relates to a central vacuum power unit comprising in combination a canister, a chamber for collecting debris, a first plate, a second plate, a third plate, a duct, a motor-fan assembly, a filter, and a first baffle. The duct extends between the first and second plates and is in fluid flow communication with respective openings defined in the first and second plates. The sidewall of the canister, the first and the second plates and the duct defines an acoustic damping chamber covered with a lining of sound absorbing material.

Abstract: A vacuum cleaner includes a cyclonic airflow chamber that facilitates the separation of contaminants from a suction airstream. The airflow chamber includes a chamber inlet and a chamber outlet, with the chamber inlet being fluidically connected with at least one of a suction nozzle and an above-the-floor cleaning tool. An exhaust filter housing includes a suction duct and an exhaust plenum, with the suction duct communicating with the chamber outlet. A suction source housing includes an open end communicating with the exhaust plenum and a closed end. A suction source is positioned within the suction source housing to define an annular exhaust flow passageway surrounding the suction source from the housing closed end to the housing open end. The suction source includes a suction inlet communicating with the suction duct and an exhaust outlet communicating with the housing closed end.

Abstract: Disclosed is a vacuum cleaner which can remove sludge, bad smells and toxic gases and discharge the filtered air to the upper portion of the vacuum cleaner to prevent the filtered air from being sucked with non-filtered air into the cleaner again. The vacuum cleaner includes: a dust collector having a suction hole; a cleaner body sealably assembled on the upper portion of the dust collector; a handle hinged on the upper portion of the cleaner body; a filter assembly assembled inside the dust collector and having a disc filter located on the lower surface of the cleaner body, an activated carbon filtering part located under the disc filter and a cone type filtering part located under the activated carbon filtering part; and an air discharging unit assembled on the air discharging part of the cleaner body.

Abstract: A motor-fan assembly for a floor care appliance having an improved working air fan for increased performance and noise reduction, a working air fan housing cover having a plurality of spiral shaped grooves, and a motor cooling air fan housing cover with slot shaped vent openings for increased cooling performance. The working air fan has a larger number of blades as compared to conventional fans wherein the blades are of two different lengths arranged in an alternating pattern circumferentially on an annular shaped disc. The blades are spaced closer together to prevent the passage of debris between adjacent blades and also to reduce flow noise. The passage between the edges of the fan blades and the working air fan cover has been widened and made uniform to aid in the passage of debris over the top of the working air fan.

Abstract: A blower having a fan mounted perpendicularly relative to an airflow discharge port. The fan is disposed within a volute formed in the housing at a rear area of the housing. This places the volute slightly behind the user's leg or hip when the blower is suspended or being held by a user along one side of the user's body. This significantly increases the ergonomics, efficiency and comfort of the blower by allowing the blower to rest more comfortably along the user's side without interference from the volute portion of the housing. This also allows the motor to be located directly underneath the handle of the housing to provide a better balance and feel to the housing when the user is holding onto the blower via the handle.

Abstract: A vacuum cleaner has a case including a dust chamber filtering dust included in air, an appliance chamber sucking the filtered air from the dust chamber and discharging the air through a discharge port, and a cord chamber storing a wound electrical cord. A fan motor assembly is installed inside the appliance chamber of the case for forcedly sucking the air inside the appliance chamber and discharging the air. An exhaust duct is installed between the fan motor assembly and the discharge port in the case and guiding the air discharged from the fan motor assembly to the discharge port, and a flowing passage is disposed between the dust chamber and the cord chamber so that the air is able to flow therein, whereby overheating of case and of the electrical cord can be prevented and the durability and reliability of the cleaner can be enhanced.

Abstract: An impeller and housing assembly with reduced noise and improved airflow includes a volute, a shaft, a housing, a central axis, and an inlet port located along the central axis. An outlet port is located on a second axis spaced from the central axis. An exhaust passage extends from the outlet port. The impeller is mounted on the shaft for rotation. The impeller includes a hub, and at least one blade extending from the hub. The blade has a distal surface spaced from the shaft. The impeller housing has a first plane which is approximately perpendicular to the central axis. The first plane contacts the blade distal surface. A second plane is parallel to and spaced apart from the first plane. The second plane contacts a wall of the outlet port at a location closest to the first plane. A spacing wall is positioned between the volute and the outlet port and spaces each blade from the outlet port, thus reducing noise and increasing airflow.

Abstract: A centrifugal blower capable of reducing noise. The centrifugal blower comprises an impeller having a hub plate and a set of blades disposed on at least one surface of the hub plate so as to surround an axis of rotation; and a casing surrounding the impeller and having a volute portion disposed at an outer peripheral portion thereof. The portion of casing facing the set of blades is formed with a plurality of through holes, whereas a sound absorbing material is attached thereto so as to cover the through holes. The noise caused by a compression wave of air occurring between the blades of impeller and the inner face of casing is efficiently absorbed by a sound absorbing material disposed adjacent the blades.

Abstract: A vacuum cleaner includes a housing having a housing passage with a passage inlet, air entering through the passage inlet flowing in a first direction and the housing passage directing air flowing therethrough in a second direction which is more than 90 degrees different from the first direction. The vacuum cleaner also includes a blower adapted to be used separately from the vacuum cleaner, the blower having a blower housing with a blower inlet, a blower outlet, and defining a blower passage between the blower inlet and the blower outlet, an impeller disposed in the blower passage to move air between the blower inlet and the blower outlet and a motor mounted to the blower housing and coupled to the impeller to move the impeller. The blower is detachably secured to the housing with the blower outlet disposed in communication with the passage inlet.

Abstract: The present invention relates to a dust collecting apparatus for eraser or the like, by designing and disposing a set of dust-conducting pipes and components and an eraser outside the housing and putting them to connect with the housing. The interior of the housing consisting of a power supply automatic-safe-breaking device and lots of display lamps, controlling and collecting components are disposed at the related places of the invention for erasing something and collecting the dust in the classroom or the like.

Abstract: A centrifugal blower comprises an impeller; and a casing, having an intake port disposed at a region opposing the air inlet portion of impeller, for accommodating the impeller. The casing is provided with a port cover constituted by rod-shaped members which are arranged in a net structure, in order to cover the intake port of casing. A trailing edge portion of the rod-shaped members is formed with a slanted surface. Due to this slanted surface, the flow of air passing through the port cover so as to flow into the air inlet portion is smoothly deflected away from the axis of rotation of impeller. As a consequence, swirls are restrained from occurring, whereby a sound-insulating effect is exhibited.

Abstract: A turbo-brush for cleaning a surface includes a casing provided with a suction opening, a rotating brush, a turbine which has a rotor provided with vanes and is operationally connected to the brush, a suction nozzle and a suction pipe connected to a suction device; the casing has a housing inside which the turbine is rotatably supported for rotating about an axis of rotation; the suction nozzle is located between said brush and said turbine for sucking an air flow from the suction opening, direct it onto the brush and then towards the turbine; the housing of the turbine has at least one lip projecting to a distance from an outer end of the vanes of the turbine which ranges from 0.001% to about 0.1% of the diameter of said rotor of said turbine.

Abstract: A vacuum cleaner includes a cyclonic airflow chamber that facilitates the separation of contaminants from a suction airstream. The airflow chamber includes a chamber inlet and a chamber outlet, with the chamber inlet being fluidically connected with at least one of a suction nozzle and an above-the-floor cleaning tool. An exhaust filter housing includes a suction duct and an exhaust plenum, with the suction duct communicating with the chamber outlet. A suction source housing includes an open end communicating with the exhaust plenum and a closed end. A suction source is positioned within the suction source housing to define an annular exhaust flow passageway surrounding the suction source from the housing closed end to the housing open end. The suction source includes a suction inlet communicating with the suction duct and an exhaust outlet communicating with the housing closed end.

Abstract: The present invention relates to a central vacuum power unit comprising in combination a canister, a chamber for collecting debris, a first plate, a second plate, a third plate, a duct means, a motor-fan assembly, a filtering means, a first baffle means, means for generating a flow of cooling air for an electric motor, and means for reducing the emission of noise outside the canister. This central vacuum power unit is characterized in that a portion of said piping passes across a further opening is provided in the plate which is provided with the seat of resilient vibration dampening material and is receiving the motor-fan assembly, in that said portion of piping has a vertical axis substantially parallel to the axis of the intake of the vacuum fan, so that any deformation of the seat due to the vacuum existing underneath the motor-fan assembly will allow the piping to slide freely in said further opening without solid contact with said plate.

Abstract: Conventional leaf blowers have a supporting frame to where the different components are attached. In order to reduce the noise from the tool and protect some of the components are they provided with covers. This makes the tool heavy and complicated for the operator to use. The claimed invention is a covering casing (10) that also is the supporting structure for the different components in the tool. The casing reduces the amount of noise spread from the tool and protects the components inside the casing (10).

Abstract: A vacuum cleaner includes a cyclonic airflow chamber that facilitates the separation of contaminants from a suction airstream. The airflow chamber includes a chamber inlet and a chamber outlet, with the chamber inlet being fluidically connected with at least one of a suction nozzle and an above-the-floor cleaning tool. An exhaust filter housing includes a suction duct and an exhaust plenum, with the suction duct communicating with the chamber outlet. A suction source housing includes an open end communicating with the exhaust plenum and a closed end. A suction source is positioned within the suction source housing to define an annular exhaust flow passageway surrounding the suction source from the housing closed end to the housing open end. The suction source includes a suction inlet communicating with the suction duct and an exhaust outlet communicating with the housing closed end.

Abstract: The vacuum includes a body having a main air passageway, and first and second air passageways diverging from the main passageway. The first air passageway defines a blower port. A closable door having an open and a closed position directs air flow from the main air passageway to either the first or second diverging air passageways to switch between vacuum and blowing modes. In one embodiment the wet/dry vacuum assembly is arranged such that each of the component parts may be placed in an assembly fixture and attached to a unit without reorienting the assembly.

Abstract: A portable power working machine has an L-shaped frame, a centrifugal blower fixed on a frame in a state that an intake port is opposed to a upright portion of the frame, and a cover having an upper portion spanned between an upper portion of the upright portion of the frame and the centrifugal blower and side portions extending from respective ends of the upper portion to a horizontal portion of the frame and spanned between a side portion of the upright portion and the centrifugal blower. A plurality of through-holes are formed in the upper portion of the cover, the through-holes communicating an interior space defined by the frame, the centrifugal blower and the cover with an exterior space on an outside of the interior space and having a size to block foreign matter in size greater than a predetermined value from passing through.

Abstract: A vacuum cleaner includes a tank assembly having an open end, a cap assembly removably connected to and generally closing off the open end, an inlet assembly disposed on one of the tank and cap assemblies, an exit opening disposed on one of the tank and cap assemblies, a vacuum source connected to one of the tank and cap assemblies for drawing process air through the inlet assembly, a filter assembly disposed between the inlet assembly and the exit opening, the filter assembly comprising a filter, and a filter bag assembly covering at least part of the filter, wherein the filter bag assembly comprises a filter bag and a drain tube connected to the filter bag. Preferably, the drain tube is integrally built into the filter bag.

Abstract: In an electric blower, exhaust air discharged radially from a centrifugal fan is redirected to a motor drive section by a diffuser and a fan cover. The air passes from a ventilation opening on a motor frame and through a bracket to cool the motor drive section. A portion of the air from the centrifugal fan is bled off through exhaust openings without passing over the motor, whereby this portion remains cooler and cleaner than the air that passes over the motor. Air flows up a wand and then passes over the motor to cool the motor. This air passes through filters before being discharged. The portion of air that is bled off passes along a parallel path in the wand to agitate dirt, and to maintain the wand relatively cool. In one embodiment, some of the bled-off portion is discharged directly without passing along the wand.

Abstract: The present invention provides a dust collect device for an eraser. It is related to a box, which has an inside box to separate the inside of the box into an inner space and an outer space. An inhaler component is set in the inside box, and it connects the inner space with the outer space. A dust bag, which is ventilated, is placed in the inner space, and it connects a dust guide pipework with the eraser to form a connective structure, so that users can operate the inhaler component at any time to absorb the dust into the dust bag. Thus, the dust is collected instead of floating and spreading in the air, so the environment can stay clean.

Abstract: A portable leaf blower having a fan unit (10) with a fan (11) and a combustion engine (12) for driving the fan. The fan unit (10) is arranged in a shell (16,17) provided with a lower inlet opening (23) through which air, during operation, flows to the fan (11). The shell is further provided with an upper opening (24). When the engine (12) has been cut off, air for cooling the engine (12) flows through the shell (16,17) by means of self convection from the lower inlet opening (23) to the upper opening (24).

Abstract: The present invention provides for noise reduction during operation of a portable blower by reducing the noise or acoustic energy escaping from the housing outlet and blower tube. The noise reduction is achieved by placing sound absorbing material in the blower tube. The sound absorbing material may include flared upstream and downstream ends to reduce turbulence. The sound absorbing material may be held within the blower tube by an insert frame such that substantial portions of the sound absorbing material are exposed to air passing through the blower tube. Also disclosed is a sound absorbing insert that can be placed within an existing blower tube to retrofit portable blowers with noise reduction technology.

Abstract: An enclosure is constructed as a back pack so that it may be worn. Air is conducted into an air intake chamber, then to an air intake plenum by air impeller. An electric motor is coupled with an air impeller, with motor cooling accomplished by the positioning of the electric motor adjacent to a motor cooling intake aperture. A sound absorbing layer lines the enclosure. Air exits through an air exhaust orifice for application in blowing leaves etc. A rotational transmission, terminating with a coupling is adapted for receiving an accessory for operation of the accessory so that a wide range of garden, carpentry and farming accessories may be utilized with the power take-off.

Abstract: A portable power working machine has an L-shaped frame, a centrifugal blower fixed on a frame in a state that an intake port is opposed to a upright portion of the frame, and a cover having an upper portion spanned between an upper portion of the upright portion of the frame and the centrifugal blower and side portions extending from respective ends of the upper portion to a horizontal portion of the frame and spanned between a side portion of the upright portion and the centrifugal blower. A plurality of through-holes are formed in the upper portion of the cover, the through-holes communicating an interior space defined by the frame, the centrifugal blower and the cover with an exterior space on an outside of the interior space and having a size to block foreign matter in size greater than a predetermined value from passing through.

Abstract: A portable leaf blower having a fan unit (10) with a fan (11) and a combustion engine (12) for driving the fan. The fan unit (10) is arranged in a shell (16,17) provided with a lower inlet opening (23) through which air, during operation, flows to the fan (11). The shell is further provided with an upper opening (24). When the engine (12) has been cut off, air for cooling the engine (12) flows through the shell (16,17) by means of self convection from the lower inlet opening (23) to the upper opening (24).

Abstract: A particular multi-functional cleaning machine, in accordance with the principles of the invention, includes a water-tank and a liquid delivery line extending from the water tank to a high-pressure spray gun. The liquid delivery line has an inner end, a pump, and an outer end, with the inner end connected to the water tank, and the outer end connected to the high-pressure spray gun. The machine also has a cleaning-liquid draw line which is connected to the liquid delivery line using a cleaning-liquid injector. Because the machine has a separate cleaning-liquid draw line, an operator is able to choose from among any of a number of different cleaning liquids stowed in containers on the machine, and to draw a particular liquid through the draw line, into the liquid delivery line, where it may be combined with water from the water tank and subsequently sprayed onto a surface to be cleaned.

Abstract: A wet cleaning apparatus having at least one outlet is provided. The apparatus has an intake fitting, for a suction air stream, which opens out into a liquid container. An upper housing part is disposed on the liquid container and has disposed therein a motor about which at least part of which flows a coolant air flow. At least one turbulence chamber is provided in which the suction air stream and the coolant air flow meet one another at an angle.

Abstract: A vacuum cleaner module including a vacuum blower head and a support assembly for positioning in an opening defined between a movable window and a corresponding window sill of a building. The support assembly mounts the blower head outside the building adjacent to the movable window and the window sill when the support assembly is positioned in the opening. Some embodiments of the vacuum cleaner further include a cyclone separator and silencer which communicates with the fan outlet of the vacuum blower head for reducing emission of dust and noise from the vacuum blower head. Other embodiments of the vacuum cleaner module further include a muffler for attenuating suction noise generated by the vacuum blower head.

Abstract: The present invention provides for noise reduction during operation of a portable blower by reducing the noise or acoustic energy escaping from the housing outlet and blower tube. The noise reduction is achieved by placing sound absorbing material in the blower tube. The sound absorbing material may include flared upstream and downstream ends to reduce turbulence. The sound absorbing material may be held within the blower tube by an insert frame such that substantial portions of the sound absorbing material are exposed to air passing through the blower tube. Also disclosed is a sound absorbing insert that can be placed within an existing blower tube to retrofit portable blowers with noise reduction technology.

Abstract: A wet/dry vacuum appliance having enhanced air-handling performance and reduced operating noise is described. In one embodiment, the collector scroll in a wet/dry vacuum is configured so as to isolate the vacuum's impeller from geometries prone to increase operating noise at particular frequencies. Further, the overall geometry and configuration of the air flow path through the power head of the vacuum is such that air-handling performance is enhanced even as noise levels are reduced. In the disclosed embodiment, the wet/dry vacuum is of the detachable power head type, although non-detachable power head implementations are contemplated.

Abstract: A power working machine has a noise level display device which enables the noise level of the machine to be easily recognized with the naked eyes. When compressed air that is pressurized and delivered by a blower fan is delivered to an air-ejecting pipe, a noise level proportional to the magnitude of the force of the ejected air flow is indicated by the noise level display device, which is mounted on the air-ejecting pipe.

Abstract: A suction cleaner comprising a motor which operates a blower in such a manner that the blower blows a flow of air out into a motor chamber that delimits a volume which extends at least radially around the motor, and then out through outlet openings arranged in said motor chamber, and wherein the motor chamber is provided with a silencer element made of a silencing material, such as foamed plastics, said silencer element enclosing the motor radially and forming a silencing chamber around the same, and wherein the silencer element is provided with flow passages which substantially constitute the flow connection from said silencing chamber to the outflow openings in the motor chamber. The fact that the flow passages in the silencer element according to the invention extend axially along the motor in substantially the entire length thereof provides an optimum silencing effect.

Abstract: Disclosed is a unique and novel air filtrating, self-propelled upright vacuum cleaner. The filtration system utilizes a HEPA-rated air filter as a final filtering element. The disclosed vacuum cleaner contains numerous other features including a self-propelled drive mechanism.

Abstract: A vacuum cleaner has an electric motor driving an air impeller for creating suction and a pump which draws liquid material through an inlet tube from the bottom of a tank and expels it from the tank. The vacuum cleaner also includes a non-water soluble collection bag that attaches to a tank inlet and is disposed within the tank. The collection bag filters large particulate material out of the material which is vacuumed into the tank.

Abstract: A low noise vacuum cleaner is comprised of a dust collecting chamber having a paper filter, and air blowing chamber partitioned by a wall. The air blowing chamber comprises an air suction motor, a front casing, a rear casing having space established by assembling with the front casing, and the motor being housed in the space, and a first and a second air guiders which are housed in the rear casing. A periphery of the second air guider is sealedly disposed between the joint portion of the front casing and the rear casing.

Abstract: A central vacuum cleaner having an air flow exhaust pipe is provided with a muffler comprising an elongated muffler pipe having a reduced diameter inlet and a reduced diameter outlet and a noise reducing foam liner disposed in the muffler pipe between the inlet and outlet. The foam liner includes a smooth inner surface that is generally flush with inner surfaces of the inlet and outlet. The foam liner comprises a combustion modified polyether polyurethane foam tube inserted in the muffler pipe between the inlet and outlet.

Abstract: A combined muffler and air deflector apparatus for a vacuum cleaner includes a body having first and second ends, the first end adapted to be coupled to a blower port of a vacuum cleaner. A cap has a first end that defines an outlet, and a second end that is coupled to the second end of the body so that the body and the cap define a passageway for directing air from the blower port to the outlet. The outlet may be generally tapered such that air flowing through the passageway from the blower port is restricted. A device is situated in the passageway for muffling sound. In one embodiment, the sound muffling device comprises a divider that creates sound reflecting chambers. In another embodiment, an acoustical pad functions as the sound muffling device.

Abstract: In a vacuum cleaner a suction motor is installed in a front casing. The front casing has a first main body with a first suction opening connected to the suction motor. An opposite side face of the first main body is opened. A lower chamber communicates with the first main body by a penetrating hole. An upper chamber is installed on an upper part of the first main body. The lower chamber and the upper chamber communicate with each other by a rear casing which covers the front casing. An air guider is installed inside the front casing. The air guider has a second opened side face, an opposite second closed side face closed with a closing plate, and a top penetrating hole formed through a top surface of the second main body. The closing plate closes the opened side face of the first main body. Thus, air sucked into the suction motor is exhausted to an inside of the air guider.

Abstract: The present invention provides for noise reduction during operation of a portable blower by reducing the noise or acoustic energy escaping from the inlet of the blower housing. The noise reduction is achieved in one respect by placing sound absorbing material in a plenum attached to the inlet opening of the blower housing. Other features of the preferred plenum include louvered openings and angled engagement members to draw the plenum tightly against the blower housing.

Abstract: A suction globe of a vacuum cleaner which can reduce noise due to friction and vortex motion generated from a suction passage of a suction globe of a vacuum cleaner. The suction globe of a vacuum cleaner, comprises a soft brush body formed to move forward or backward through a front roller and a rear roller; a brush cover formed over the soft brush body; and a connection holder having a connection passage extended from a body passage formed in the soft brush body through the brush cover, on which body passage hairs with a predetermined length are planted.

Abstract: A rotary positive blower is driven by a drive device and has an intake port and an exhaust port. A plurality of conduit arrangements each having an inlet coupled to the exhaust port and an outlet, each of the plurality of conduit arrangements have a first predetermined diameter in at least a given portion; and a restriction is disposed in at least one of the plurality of conduit arrangements between the inlet and the outlet of this at least one arrangement, the restriction has a predetermined length and a second predetermined diameter less than the first predetermined diameter to cooperate in reduction of noise and improved efficiency of the drive device and the rotary positive blower.

Abstract: An electric fan comprises: a radial impeller for expelling the air trapped therein out of the impeller; a diffuser having a multiplicity of air passages separated by air guides, the air passages adapted to receive the air expelled from the impeller; a fan case for covering the impeller and the air guides; at least one throughhole which is formed in the fan case for each of the air passages; and a silencer equipped with a multiplicity of silencer cavities each having a predetermined volume and communicating with a corresponding one of the air passages, the silencer covering the fan case. The silencer is provided either on top of or beneath the fan case. Because the volumes of these silencer cavities may be chosen arbitrarily such that the silencer cavities may absorb noise caused by the interference between the impeller and the air passages, even audible noise may be suppressed sufficiently.

Abstract: A suction nozzle of a vacuum cleaner enables to reduce the noise produced by air friction and whirlpool in the suction flow route. A suction nozzle of a vacuum cleaner has a soft brush body provided with a front roller and a rear roller, thereby being moved by the front and rear roller, and formed the plurality of hole along a suction flow route. A brush cover is formed at an upper side of the soft brush body. A brush holder provided with a connection flow route connected with the suction flow route formed at the soft brush body through the brush cover. A noise absorbing material is formed at oppsite side of the suction flow route to closely adhere on the hole.