JP2013170807A - Range hood - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silent range hood not generating noise.SOLUTION: A cell noise absorbing body 51 is mounted in an intake air opening IN of a range hood 50 serving as a noise emitting port. In this case, the cell noise absorbing body 51 includes a honeycomb cell 5A as a parallel assembly composed of numberless narrow tubular cells and an air-impermeable honeycomb bottom surface 5B, and is mounted in a mode where the honeycomb cell 5A is directed inward and the intake air opening IN of the range hood 50 is closed by the honeycomb bottom surface 5B while leaving predetermined intake air passages F. The sound pressure of noise vibrates an air spring partitioned by the honeycomb cell 5A, and energy is drained by the vibration thereof, or canceled.

Description

  The present invention relates to a range hood that is installed and used at a position above a cooking heat source such as a gas range or an IH heater in order to discharge cooking smoke to the outdoors.

  An exhaust fan for forcibly discharging cooking smoke generated in the kitchen to the outside is usually installed at an appropriate position on the outer wall that divides the kitchen and the outside. A general exhaust fan is installed sideways in an exhaust opening formed in an outer wall that partitions the kitchen and the outside, and has a poor function of selectively capturing cooking smoke and exhausting it outdoors. Therefore, the exhaust fan is attached with a range hood that efficiently captures cooking smoke and guides it to the exhaust fan.

  The range hood has an intake opening for taking cooking flue gas above a cooking heat source in the kitchen, and is configured to form a flue duct extending from the intake opening to the exhaust fan. A plurality of duct surfaces for forming a flue duct is usually a sheet metal processed product of a sheet steel plate, and a flue duct is formed by spot welding means, lap bending caulking means, riveting means, etc. It is assembled by integrating. That is, it is a simple surface configuration product having no reinforcing frame or reinforcing bar other than the duct surface. The flue duct is formed in a shape that gradually reduces the cross-sectional area from the intake opening to the exhaust fan.

  Regarding the range hood having the above-described characteristics in material, structure, and shape, a problem has been pointed out that considerable noise is generated with the operation of the exhaust fan. This problem is not a problem that arises under specific conditions due to individual circumstances in each household, but is a noisy general theory. This is also clear from a simple questionnaire survey on the Internet that the response that the operation sound of the kitchen ventilation fan feels noisy is overwhelmingly the response that the operation sound is not particularly noisy.

  Therefore, as a preliminary preparation for quieting the range hood, the acoustic mechanism that generates noise from the range hood was investigated and examined, and as a result, it was found that the following phenomenon occurred.

  First, when the exhaust fan with a high suspicion as a noise source was removed and the operation sound of the exhaust fan alone was examined, the noise level of the exhaust fan alone was extremely low, and there was no particular noise that could be noticed. found.

Next, after removing the range hood, an exhaust fan was installed at a predetermined location, that is, an exhaust opening provided on the wall surface, and operation noise was confirmed. In this case, although the range hood is eliminated, the noise level is considerably higher than the operation sound of the exhaust fan alone. As a result of investigating the cause, it was found that wind noise and resonance sound were generated from the weather cover attached to the outdoor side of the exhaust opening and propagated indoors.

  The weather cover of the exhaust fan installed on the outdoor side is installed for the purpose of preventing wind and rain from blowing into the indoor side from the exhaust opening provided on the outer wall. Therefore, the weather cover is formed in such a shape that the exhaust flow from the exhaust fan collides and the direction is controlled downward to exhaust. For this reason, although a smooth curved surface is adopted, a considerable wind noise is generated. In addition, the exhaust flow from the exhaust fan at this time is not a uniform air flow but a waved air flow with periodic pressure fluctuations determined by the number of rotations of the exhaust fan and the number of fan blades. This wave is parasitic on the weather cover and generates resonance sound.

  However, the low-level operation sound of the exhaust fan alone or the sound that leaks from the outdoor weather cover to the room itself does not cause a problem that the kitchen exhaust fan is noisy. However, by attaching the range hood that has been removed, the situation changes completely, and a loud noise that is the subject of complaints is generated.

  The fact that the low level noise is changed to the high level noise by attaching the range hood means that the range hood functions as a horn. That is, the air flow path of the range hood gradually moves from the intake opening that opens large above the heat source for the kitchen toward the exhaust fan, as in the case of the acoustic horn used to improve the acoustic conversion efficiency. Are formed so as to reduce the cross-sectional area. For this reason, the range hood functions as a kind of horn that uses sound generated from the exhaust fan and the weather cover as a sound source. In addition, when a hand is touching the range hood that is generating noise, it can be seen that vibration equivalent to horn squealing is parasitic. This is because the range hood is a surface-configured product of a sheet steel plate that easily vibrates.

  Although there are few prior arts that directly capture the above-mentioned noise problem in a range hood as a kitchen facility, examples of related technologies and peripheral technologies are shown below for reference.

JP-A-6-281225 JP-A-7-71801 Japanese Patent Laid-Open No. 10-281515 JP 2007-3157 A JP 2008-82581 A

  Of the prior proposal examples exemplified in the above-mentioned prior art document column, the technique most likely to be relevant to the present application is the technique described in Patent Document 2. Therefore, I will mention a little about this technology.

  The technology described in Patent Document 2 is intended for a range hood that includes a baffle plate for improving the collection efficiency of smoke and the like at the suction port, and without reducing the collection efficiency of smoke or the like by the baffle plate. The purpose is to effectively reduce the sound generated from the above.

  And the content of the technical means employ | adopted in order to achieve the said objective is to form a baffle board with the sound-absorbing material which has space inside. At this time, the term sound-absorbing material having a space inside is defined to refer to a frame body in which a cavity is formed. In addition, the frame body is particularly preferably made of a copper plate from the viewpoint of required rigidity and nonflammability.

  However, it is difficult to understand how a copper plate frame having a cavity formed therein can be said to be a sound absorbing material.

  In addition, in the same document, the frame body can be filled with inorganic fibers such as glass wool and rock wool, or a foamed resin plate having fine air bubbles inside, a foam metal plate, There is a description.

  I think here, the sound absorbing material having a space inside said in the same document is not a frame itself, but an inorganic fiber such as glass wool or rock wool inside the frame as a strength member, or a fine inside. It is understood that it is appropriate to interpret the term to indicate a foamed resin plate having air bubbles and a foam metal plate filled, and such an interpretation does not contradict the intention of the inventors of the present invention. It seems to be.

  According to the above interpretation, the technical gist of the invention of the same document is that in a range hood provided with a baffle plate, the baffle plate is a foamed resin plate having inorganic fibers such as glass wool and rock wool inside, or fine air bubbles inside. The gist is that it is formed of a frame filled with a foam metal plate. In addition, regarding the attachment of the baffle plate, it is described that the side provided with glass wool or the like should be attached to the inside of the apparatus.

  That is, although the technique described in Patent Document 2 is characterized by the selection of attachment locations such as glass wool, the sound absorption mechanism uses a fibrous sound absorbing material such as glass wool or a porous sound absorbing material such as foamed polyurethane. It can be evaluated that it is based on the conventional means of the noise prevention related invention characterized by (see Patent Document 1, Patent Document 3 to Patent Document 5). In addition, although the technique of patent document 2 is related with the range hood provided with a baffle board, about the range hood which is not provided with a baffle board, it is thought that it can be applied on a baffle board or a member equivalent to this. Therefore, the presence or absence of the baffle plate need not be a problem.

  Including the invention described in Patent Document 2 described above, the invention that attempts to reduce the noise level around the range hood by relying on the fibrous sound absorbing material or the porous sound absorbing material has the following problems.

  First, the sound-absorbing effect by the fibrous sound-absorbing material or the porous sound-absorbing material is proportional to the amount and has a characteristic that a significant effect cannot be obtained unless it is used in a large amount. In this regard, the general shape of the range hood is a shape that opens in a direction that gradually expands downward, so that it has a structural characteristic that a large amount of sound absorbing material that does not have the ability to maintain its own shape cannot be attached. Yes. Therefore, it is desired to use a sound absorbing material that is easy to attach and has good sound absorption efficiency.

  In addition, there will be a view that the use of dangerous substances such as glass wool and rock wool around food itself is out of the question, and porous sound absorbing materials that can be used instead of these are used. In general, when used in a range hood, there is a concern that the sound absorption performance may be rapidly deteriorated within a short period of time due to clogging. Accordingly, it is desirable to use a sound absorbing material that does not depend on a fine bubble structure that easily clogs and is difficult to clean, such as a porous sound absorbing material, around the range hood.

  The present invention is based on the above-described results of examination of the prior art, by applying to the range hood a sound absorbing material having a honeycomb structure that has no fear of toxicity to the human body and can maintain a high sound absorbing effect over a long period of time. An object of the present invention is to provide a range hood that achieves noise reduction by suppressing the harmful horn effect, parasitic vibration, and the like that expand and emit low-level noise.

  In order to solve the above problems, the present invention employs the following configuration.

(Solution 1)
The range hood of the present invention has an intake opening for taking cooking flue gas above a cooking heat source in a kitchen, and an outer wall that partitions the kitchen and the outside by a plurality of duct surfaces surrounding the intake opening In a range hood configured to form a flue duct leading to an exhaust fan installed in a honeycomb, one side of a honeycomb cell, which is a parallel assembly of countless tubular cells, is formed on the bottom surface of an air-impermeable honeycomb. In this case, the cell sound absorber is formed to have an outer dimension smaller than the outer dimension of the intake opening, and a predetermined intake air is formed between the honeycomb cell and the duct surface. It is attached in such a manner that the intake opening is closed by the bottom surface of the honeycomb leaving the passage.

  The solving means 1 will be described. The range hood is installed above the heat source for cooking in the kitchen. The range hood has an intake opening for taking cooking flue gas above the cooking heat source. The range hood is configured to form a flue duct from the intake opening to the exhaust fan by a plurality of duct surfaces. The larger the intake opening portion, the greater the ability to collect cooking flue gas. However, in the vicinity of the exhaust fan, the exhaust efficiency increases when the exhaust fan is closer to the sweep area. Therefore, the flue duct is formed in an overall shape so as to reduce the cross-sectional area toward the exhaust fan as a rule. As a result, the operating noise of the exhaust fan and the incidental sound caused by the weather cover installed behind the exhaust fan increase the sound pressure level by a kind of horn effect that is unintentionally exhibited based on the shape of the flue duct. It will be discharged from the opening.

A cell sound absorber is attached to the intake opening of the range hood. This cell sound absorber comprises a honeycomb cell and a honeycomb bottom surface.

A honeycomb cell is a parallel assembly of an infinite number of small tubular cells. The material of the honeycomb cell is not particularly limited. The honeycomb bottom surface is a non-breathable planar member that is attached to or integrally molded with one side of the honeycomb cell, and has a function of closing openings on one end side of countless cells. The material for the bottom surface of the honeycomb is not particularly limited as long as it is non-breathable. Such a cell sound absorber is formed to have an outer dimension that is smaller than the outer dimension of the intake opening, and the honeycomb opening is closed by the honeycomb bottom surface leaving a predetermined intake passage between the duct cell and the honeycomb cell facing inward. It is attached in a manner.

  Cooking smoke rising from the vicinity of the cooking heat source in the kitchen collides with the honeycomb bottom surface of the cell sound absorber mounted so as to close the intake opening, and turns to the side along the honeycomb bottom surface. It is taken into the range hood through an intake passage set between the body and the surrounding duct surface.

  The cooking flue gas or the like taken into the range hood is sucked toward the exhaust fan through the flue duct and discharged to the outside. On the other hand, the operating noise of the exhaust fan and the incidental noise accompanying the exhaust are propagated to the intake opening through the flue duct. The propagated noise collides with the honeycomb cell side of the cell sound absorber attached so as to close the intake opening.

  A honeycomb cell is a structure having almost no sound reflection surface because it is a parallel assembly of an infinite number of narrow tubular cells. Therefore, the sound pressure that has collided with the honeycomb cell is spilled into the honeycomb cell in a state of being divided into an infinite number of cells. However, since one side of the honeycomb cell is blocked by the honeycomb bottom surface, the honeycomb cell cannot pass outside the range hood through the honeycomb cell. That is, the sound pressure of the noise that has collided with the cell sound absorber cannot be reflected at the surface level of the honeycomb cell or escape to the opposite side.

  Air is an elastic body, and sound is an air dense wave. The existing air that is partitioned in each cell of the honeycomb cell functions as an air spring against the sound pressure that spreads. As a result, the sound pressure that has collided with the honeycomb cells causes the air springs in each cell to act according to the density state, and the air springs vibrate so as to repeat livestock and release. That is, the air spring is also in a dense state. The frequency of the air spring at this time is synchronized with the frequency of the sound.

  Specifically, the sound pressures are synchronized so that the density of the sound pressure corresponds to the density of the air spring. That is, the dense energy of sound pressure is exhausted by compressing the air spring in each cell into a dense state. The air spring then tries to release the energy that is stored. The energy release action of the air spring at this time corresponds to the rough state of the sound pressure. Therefore, the energy released from the air spring is filled with the sound pressure in the rough state and exhausted.

  The silencing mechanism by the honeycomb cell as described above can be regarded as a canceling neutralization action of the sound density state, or can be regarded as inverting the phase of the sound density state. However, the present invention is not intended to elucidate which one of the two views is correct, but is intended to utilize the overwhelmingly clear silencing action of the honeycomb cell.

  In addition, there seems to be various theories different from the above reasoning regarding the sound absorbing action of the honeycomb structure such as the cell sound absorbing body of the present invention, but these opinions are claimed as the explanation theory of the sound absorbing action as a fact. Therefore, in any case, the existence of the sound absorbing action is not denied.

  Moreover, since the sound absorbing action of the cell sound absorber based on the sound absorbing mechanism as described above does not depend on the material, it can be formed of a washable material, and the hygienic state of the range hood is concerned by the use of the cell sound absorber. There is no fear. Moreover, since the diameter of each cell constituting the honeycomb cell is much larger than that of the porous sound-absorbing material, there is no possibility of clogging, so that the initial performance can be maintained for a long time.

(Solution 2)
The range hood of the present invention can be configured to include a cell sound absorber on the duct surface forming the flue duct in addition to the cell sound absorber attached in a manner to close the intake opening.

  The solving means 2 will be described. Since the sound propagating in the flue duct from the exhaust fan side to the intake opening is a kind of pressure wave, it propagates while acting on all surfaces forming the flue duct. Therefore, by installing a cell sound absorber on the duct surface forming the flue duct, it is possible to absorb the sound pressure at the previous stage leading to the intake opening, thereby further enhancing the final sound absorption effect. it can. In addition, by adjusting the diameter and depth of each cell that constitutes the honeycomb cell, the cell sound absorber installed in the intake opening and the cell sound absorber installed in the duct surface absorb sound in different bands. It can also be.

(Solution 3)
The range hood of the present invention, in addition to the cell sound absorber attached in such a manner as to close the intake opening, has a honeycomb cell attached to the duct surface forming the flue duct, and bears the function of the honeycomb bottom surface on the duct surface. It can be set as the structure made to do.

  The solving means 3 will be described. The above solution means that the function of the honeycomb bottom surface of the cell sound absorber can be imposed on the duct surface. The requirement for the bottom surface of the honeycomb is that it is non-breathable and can block one side of the honeycomb cell. The duct surface of the range hood satisfies this requirement. Therefore, by attaching only the honeycomb cells to the duct surface, a cell sound absorber substantially having a honeycomb bottom surface is formed.

(Solution 4)
The range hood of the present invention may have a configuration in which an intake passage set between a duct surface forming an intake opening and a cell sound absorber is bent in a step shape.

  The solving means 4 will be described. The above solution is intended to prevent leakage of sound in a frequency band with high straightness from an intake passage set between the cell sound absorber and the surrounding duct surface. That is, an intake passage is necessary for the range hood, and this cannot be omitted. However, when the intake passage is positioned linearly with the inside of the duct, it is inevitable that noise components leak through the intake passage. Therefore, by bending the intake passage in a staircase shape, at least the mid-high range component having a strong straightness in the noise component can be greatly attenuated.

(Solution 5)
The range hood of the present invention can be configured such that the cell sound absorber is formed from a pulp-based or resin-based material, and the honeycomb bottom surface is subjected to a flameproofing process by means of attaching a metal sheet.

  The solving means 5 will be described. In the case of using a pulp-based or resin-based material for reasons other than the sound absorbing performance as the material of the cell sound absorber, for example, suitable for disposable use, lightweight and easy to wash, for example, in a tempura pan There is concern about the poor fireproofing and fireproofing performance in the event of an accident such as a fire. Therefore, when a material that is vulnerable to fire is used as the material of the cell sound absorber, the cell sound absorber is used by means of attaching a metal sheet to the honeycomb bottom surface facing the heat source side for the kitchen. It shows that fire resistance or fire resistance can be easily given to the body.

The range hood of the present invention has an intake opening for taking cooking flue gas above a cooking heat source in a kitchen, and an outer wall that partitions the kitchen and the outside by a plurality of duct surfaces surrounding the intake opening Incorporating a special sound absorbing member into the range hood that is configured to form a flue duct leading to the exhaust fan installed in the air, specifically, as a sound absorbing member, a parallel assembly of countless tubular cells Adopting a cell sound absorber that covers one side of the honeycomb cell with a non-breathable honeycomb bottom surface, leaving a predetermined intake passage for sucking cooking smoke in the intake opening of the range hood, and intake air by the honeycomb bottom surface The mode of closing the opening, that is, inhibiting the function as the range hood by attaching the cell sound absorber with the honeycomb cell facing the inside of the range hood In addition, the noise of exhaust fans expanded by the range hood is released into the honeycomb cells of the cell sound absorber, and the sound pressure energy is exhausted in each cell. Because it can be extinguished by a sound absorbing mechanism, an overwhelmingly quiet range hood is realized compared to the conventional range hood.

  Further, the cell sound absorber composed of the honeycomb cell and the honeycomb bottom surface does not cause the clogging phenomenon unlike the porous sound absorbing member, and thus has an advantage that a high sound absorbing effect can be maintained for a long period of time.

It is a see-through | perspective perspective view which shows embodiment of the range hood of this invention. It is sectional drawing of the side view of the range hood shown to the said embodiment. It is a perspective view of the cell sound absorption body incorporated in the range hood shown in the said embodiment. It is an expanded sectional view of a cell sound absorber shown in the above-mentioned embodiment. It is operation | movement explanatory drawing of the cell sound absorber shown in the said embodiment. It is sectional drawing of the side view which shows other embodiment of the range hood of this invention. It is sectional drawing of the side view which shows other embodiment of the range hood of this invention. It is sectional drawing of the side view which shows embodiment of the cooker hood of this invention.

  Hereinafter, embodiments of the range hood of the present invention will be described with reference to the drawings.

  The illustrated range hood 50 is a surface-configured product by sheet metal processing that includes a top surface 1, which is a duct surface made of a sheet steel plate, left and right side surfaces 2, 2, a front surface 3, and a back surface 4. It is installed along the outer wall W where the exhaust fan 10 is installed above the heat source 30 for cooking the kitchen (FIG. 1). A weather cover for the exhaust fan 10 is attached to the outside of the outer wall W.

  Each duct surface constituting the range hood 50 is assembled so as to form a truncated pyramid-shaped flue duct whose cross-sectional area decreases upward, and a lower end of the duct hood 50 is a square that opens greatly above the cooking heat source 30. And the intake opening IN (FIGS. 1 and 2). A baffle plate 5 that controls the air flow inside is incorporated in the range hood 50. A dust filter 6 is usually stretched between the intake opening IN and the exhaust fan 10.

  The cell hood 51 is incorporated in the range hood 50 so as to block the intake opening IN. The overall outer shape of the cell sound absorber 51 is dimensioned to be smaller than the outer shape of the intake opening IN formed by the four-circumferential duct surfaces, and the front surface 3, side surfaces 2, 2, Between the back surface 4, intake passages F for taking in cooking smoke are secured.

  The cell sound absorber 51 includes a honeycomb cell 5A and a honeycomb bottom surface 5B (FIGS. 1 to 3). The honeycomb cell 5A is a parallel assembly of countless cells 5S. In the honeycomb cell 5A used in the present embodiment, the diameter of each cell 5S is 5 mm square and the cell thickness D is about 8 centimeters. In addition, this cell thickness D corresponds to the depth L of each cell 5S (refer FIG. 4).

One side of the honeycomb cell 5A constituting the cell sound absorber 51 is closed by a non-breathable honeycomb bottom surface 5B. In addition, the non-breathability means that the air is not easily communicated, and the non-breathability in a strict sense is not required. In addition, the cell sound absorber 51 in the present embodiment is formed by integrally forming the honeycomb cells 5A and the honeycomb bottom surface 5B from a resin material, but may be individually molded and bonded. Such a cell sound absorber 51 is incorporated in the range hood 50 with the honeycomb cell 5A facing the inside of the range hood 50 and the honeycomb bottom surface 5B facing downward. In addition, when the honeycomb cell 5A or the honeycomb bottom surface 5B is formed of a non-refractory material, it is preferable that the honeycomb bottom surface 5B is subjected to a flameproofing process using a metal sheet 5M.

  There is no difficulty in assembling the cell sound absorber 51 to the range hood 50. As a precaution, as shown in FIG. 3, for example, a hook 5T is provided at four corners of the cell sound absorber 51 (FIG. 3), and a hook (not shown) is provided on the side surfaces 2 and 2 of the range hood 50. In addition, it can be assembled by any method. Desirably, it is a structure that does not fall in the event of an earthquake or the like.

  The above-described range hood 50 can take in cooking smoke from the vicinity of the heat source 30 for cooking through the intake passage F without any trouble and discharge it to the outdoors through the exhaust fan 10. On the other hand, noise generated near the exhaust fan 10 and about to be emitted from the intake opening IN via the flue duct is received and absorbed by the cell sound absorber 51, thereby realizing extremely quiet operation sound. .

  Although the present invention is not intended to elucidate the sound absorbing mechanism itself of the cell sound absorber 51, the sound absorbing mechanism is simply disclosed within a range elucidated by the Company. Moreover, there is an objection about the sound absorption mechanism of such a structure, and definite elucidation by a scholar who handles waves is desired in determining the best form.

  Each cell 5S constituting the honeycomb cell 5A of the cell sound absorber 51 is a bottomed cylindrical body having a predetermined cross-sectional area and a depth L (FIG. 4). If the thickness of the cell partition walls 5K constituting the honeycomb cell 5A is ignored, the wave of the sound that collides with the cell sound absorber 51 affects each cell 5S... Only in the cross-sectional area of each cell 5S. It is thought that this is not possible (FIG. 5).

  When the sound collides with the honeycomb cell 5A, the positive pressure wave P1... And the negative pressure wave -P1... As a periodic pressure wave having positive and negative properties in the air existing in the closed cell 5S are sequentially generated. Means to collide. At this time, since the air in each cell 5S has no escape space, it is considered that the air in each cell 5S functions as an air spring AS against a periodic pressure wave.

  The positive pressure wave P1... Has a force to compress the air spring AS in the cell 5S. The first positive pressure wave P1 reaching the honeycomb cell 5A (FIG. 5A) enters the cell 5S while compressing the air spring AS in the cell 5S (FIG. 5B), and the energy of the positive pressure wave P1 is air. The positive pressure wave P1 is extinguished by the spring AS (FIG. 5C).

  Next, simultaneously with the operation of releasing the energy of the positive pressure wave P1 generated by the air spring AS, the first negative pressure wave -P1 proceeds into the cell 5S. Therefore, the energy of the positive pressure wave P1 released from the air spring AS is filled in the negative pressure wave -P1, the negative pressure wave -P1 disappears, and the air spring AS returns to the free length (FIG. 5D). ). At this time, the second positive wave P2 has arrived at the cell 5S.

Next, the positive wave P2 of the second wave acts on the air spring AS that has returned to the free length, and the canceling operation similar to the above is repeated. As a result of simple measurement, each cell 5S
It can be observed that such a silencing effect exerted by is almost independent of frequency in the range in which the air spring AS in the cell 5S functions as a spring. That is, it is possible to clearly mute the broadband sound within the audible frequency.

  It should be noted that how the sound absorption effect changes when the depth of the cell 5S is increased and decreased as much as possible, and how the sound absorption effect changes when the cross-sectional area of the cell 5S is expanded without limit and when it is decreased. It is being elucidated.

  Although there are various product forms of the range hood 50, since there is no range hood 50 that does not have the intake opening IN, the present invention can be adapted to various range hoods 50 without any special design change (FIGS. 6 to 6). FIG. 8). Further, only the honeycomb cell 5A constituting the cell sound absorber 51 can be used (FIG. 6).

  When the range hood 50 has a slit structure or a punching metal baffle plate 7 at the intake opening IN, the cell sound absorber 51 is installed on the front surface of the baffle plate 7 (FIG. 6), thereby baffle. Sound emitted from the intake opening IN via the plate 7 can be silenced. A plurality of cell sound absorbers 51 can be used in combination. In this case, when the cell sound absorber 51 is directly attached to any duct surface constituting the flue duct, for example, the front surface 3, the cell sound absorber 51 is used. The honeycomb bottom surface 5B of the body 51 can be omitted. This is because the duct surface functions to close one side of the honeycomb cell 5A as the honeycomb bottom surface 5B.

  The honeycomb cell 5A of the cell sound absorber 51 incorporated in the range hood 50 does not need to have a uniform cell thickness (FIG. 7). The range hood 50 in this figure has a symmetrical front surface 3 and back surface 4, and is of a type used by being installed on a ceiling portion at the center position of a large room. The cell sound absorber 51 used has a thick cell thickness D of the honeycomb cell 5A in the central portion, following the shape of the internal space of the intake opening IN. Although being elucidated, it is possible to improve the silencing effect on sounds in various frequency bands within a range that can be confirmed.

  When the cell sound absorber 51 is incorporated in the range hood 50, an intake passage formed between the cell sound absorber 51 and the surrounding duct surface, for example, the cell sound absorber 51 and the front surface 3, or between the cell sound absorber 51 and the back surface 4. F... Can prevent direct emission of internal noise by forming it in a step shape. This is a simple thing, but it has a very useful noise reduction effect.

W Outer wall F Intake passage 10 Exhaust fan IN Intake opening 1 Top surface (duct surface)
2 Side surface (duct surface)
3 Front (duct surface)
4 Back (duct surface)
30 Heat source for cooking 50 Range hood 51 Cell sound absorber 5A Honeycomb cell 5B Honeycomb bottom surface 5S Cell

Claims (5)

An exhaust fan installed on the outer wall that separates the kitchen and the outside by a plurality of duct surfaces surrounding the intake opening, having an intake opening for taking in cooking smoke above the heat source for cooking in the kitchen In a range hood configured to form a flue duct that leads to
A cell sound absorber formed by closing one side of a honeycomb cell, which is a parallel aggregate of countless tubular cells, with a non-breathable honeycomb bottom surface is attached to the intake opening,
The cell sound absorber is formed to have an outer dimension smaller than the outer dimension of the intake opening, and the intake opening is formed by the honeycomb bottom surface leaving a predetermined intake passage with the honeycomb cell facing inward and the duct surface. A range hood, characterized in that it is attached in a manner that closes the part.   The range hood according to claim 1, wherein the cell sound absorber is attached to a duct surface forming the flue duct in addition to the cell sound absorber attached in a manner to block the intake opening.   In addition to the cell sound absorber attached in a manner to block the intake opening, the honeycomb cell is attached to the duct surface forming the flue duct, and the function of the honeycomb bottom surface is borne on the duct surface. The range hood according to claim 1.   The said intake passage formed between the duct surface which forms the said intake opening part and the said cell sound absorber is bent and formed in the step shape, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. The range hood described in 1.   The cell sound absorber is formed of a pulp-based or resin-based material, and the honeycomb bottom surface is fireproofed by means for attaching a metal sheet. Range hood according to item.

Images