Push-pull type exhaust hood

Abstract

To provide a push-pull type exhaust hood which enables a worker to perform work safely with security, high operability, and an open feeling.SOLUTION: A push-pull type exhaust hood comprises: a hood body 12 including an opening 22 on an upper surface of a wall body 14 enclosing a horizontal work table 13 and having a working area 26 with an LED for indirect lighting including a push mechanism 24 and a pull mechanism 25 which form an air curtain airflow; and a support leg part 42 supporting the hood body 12. The wall body 14 is arranged providing a forward inclining gentle slope 23 at the opening 22. The push mechanism 24 includes an air fan which is incorporated into a hollow front wall part 15 to supply air forcibly to the working area 26. The pull mechanism 25 is configured to draw air with an exhaust duct which forcibly exhausts air through an exhaust port 39a of a top plate part 39 covering an exhaust passage between a rear wall part 16 and a slit plate 34. The support leg part 42 includes a foot switch 47 which enables on / off control of various types of electric functions.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This invention is a technology relating to a push-pull type exhaust hood that not only enables forced exhaust while greatly reducing the required exhaust air volume while containing specific chemical substances, organic solvents and odors in research laboratories and laboratories, but also enables researchers to carry out various necessary experiments safely and with excellent operability in a comfortable research environment and psychological state. [Background technology]

[0002] An exhaust hood, also called a fume hood, is a necessary device for safely conducting various chemical experiments in laboratories and laboratories in research laboratories. The hood body of a conventional exhaust hood is equipped with a liftable sash window for opening and closing the front opening of the treatment chamber, and by drawing air so that the inside of the treatment chamber is in a negative pressure atmosphere, harmful gases including toxic gases generated during the experiment can be forcibly exhausted through an exhaust duct to a purification treatment means such as an exhaust gas cleaning device installed outdoors.

[0003] In this case, efforts have been made to find a method for fume hoods (exhaust hoods) that can satisfy both the requirement to minimize the amount of conditioned air taken in by the laboratory and the requirement to smoothly exhaust harmful gases without allowing them to remain in the treatment chamber. The applicant of the present application has proposed a structure, such as that shown in Patent Document 1 below, that can exert an excellent containment function while suppressing the amount of conditioned air taken in from the front opening of the treatment chamber of the hood body. [Patent Document 1] JP 2009-95771 A

[0004] In other words, the hood body in Patent Document 1 is arranged so that, via an air supply passage connected to an air supply fan, it is possible to freely simultaneously form an air curtain air flow that is supplied from the surface of the lift-up sash window through the front opening into the treatment chamber, a side side laminar flow that is supplied from each gap in the compartment along the left and right side plate portions in the direction of the baffle plate, and a plane side laminar flow that is supplied through the air outlet of the air supply portion in the horizontal direction of the treatment table portion.

[0005] For this reason, according to the fume hood described in Patent Document 1, the hood body can form an air curtain air flow that is supplied into the treatment chamber from the front opening through the lift-up sash window, effectively suppressing the generation of induced wind that is drawn from the treatment chamber toward the laboratory side as people move in front of the front opening.In addition, it can form a side-side laminar flow that is supplied separately in a diagonally downward direction along each side panel portion from each gap in the compartment, so that relatively light gas that tends to stagnate in the upper part of the treatment chamber can be forcibly sent to the exhaust path side.Furthermore, by forming a plane-side laminar flow that is supplied in the horizontal direction through the air outlet of the air outlet section, it is also possible to forcibly send relatively heavy gas above the treatment platform to the exhaust path side. DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0006] However, since the fume hood disclosed in Patent Document 1 was developed and provided based on a design concept that pursued practical functionality to obtain the desired performance, it was believed that there was room for further improvement from the perspective of enabling workers engaged in research work to carry out various necessary experiments with excellent operability in a comfortable research environment and psychological state.

[0007] In other words, the above-mentioned fume hood was formed by a structure that enclosed the work area with side walls that were arranged to enclose three sides (the left and right sides and the back side) of the horizontal work table and a lift-up sash window arranged in the front opening. Therefore, when working, it was necessary to manually raise and lower the lift-up sash window, and it was installed in a vertical position that stood in front of the worker and blocked their view, making the researcher feel more oppressive than necessary during research work. Therefore, further improvements and improvements were sought from the perspective of improving workability and providing a favorable work environment with a rich sense of openness.

[0008] In view of the above problems with the prior art, the present invention has an object to provide a push-pull type exhaust hood that eliminates any enclosing structure from the entire hood, thereby enabling workers to smoothly begin research work and providing a favorable sense of openness in an excellent research environment while engaging in research. [Means for solving the problem]

[0009] The present invention has been made to achieve the above object, and provides a horizontal work platform that is substantially rectangular in plan view and is surrounded on all four sides by walls with an opening on the upper surface thereof, and is composed of a hood body portion provided with a work area equipped with LEDs for indirect lighting and equipped with a push mechanism and a pull mechanism that can freely form an air curtain air flow from the front edge side of the opening toward the rear edge direction, and a support leg portion that integrally supports the hood body portion from below, and each of the walls is disposed correspondingly with a determined wall height so as to provide a gentle forward inclination surface with respect to the opening, and the push mechanism is incorporated into the front wall side to forcibly send air in the direction of the work area. The pull mechanism is configured to freely draw air from the direction of the work area through an exhaust duct that can freely force exhaust from an exhaust port provided in a top plate portion that covers the upper opening side of the exhaust passage secured between the rear wall body and a slit plate erected on its inside, and the most important feature is that the support leg side is equipped with a foot switch that can freely control the ON / OFF of the indirect lighting LED and the piano sound melody at least when the push mechanism and the pull mechanism are started and stopped, and can control the ON state of the indirect lighting LED while work is continuing.

[0010] In the present invention, at least the left and right wall members are preferably provided with curved eaves that are curved inwardly of the work area.

[0011] In the present invention, it is desirable for the hood main body to be provided with an opening / closing lid that is pivotally supported on the front edge side of the top plate and is located in the opening and can freely open and close the central blank area formed between the left and right walls and the front edge of the top plate.

[0012] The slit plate in the present invention is preferably provided with a sliding door structure that allows the amount of forced exhaust by the pull mechanism to be variable. Effect of the Invention

[0013] According to the invention described in claim 1, the hood main body has a work area equipped with a push mechanism and a pull mechanism that form an air curtain air flow from the leading edge side of the opening to the trailing edge side, so that workers can smoothly perform necessary experimental work, etc. in a safe and secure work environment provided by the air curtain air flow.

[0014] In addition, the work area is formed with a gentle forward slope by determining the height of each of the four walls and arranging them in relation to the opening, thereby eliminating the oppressive view obstructions that can be caused by conventional lift-up sash windows and providing an open, clear work environment.

[0015] Furthermore, the work area is equipped with indirect lighting LEDs installed near the opening, so it is lit up with gentle, indirect light without glare, allowing workers to carry out the necessary tasks comfortably and smoothly.

[0016] Furthermore, the support leg is equipped with a foot switch that can freely control the ON / OFF of the indirect lighting LED and electronic melody at least when the push mechanism and pull mechanism are started and stopped, and can control the ON state of the indirect lighting LED while work is continuing, so that by providing the worker with visual and auditory stimuli, they can prevent themselves from forgetting to turn the switch off.In addition, even if their hands are full, they can operate the indirect lighting LED with just their feet to flash or play an electronic melody for a short time when work begins and ends, and the indirect lighting LED can be kept lit in a dim light without glaring even while work is continuing, thereby maintaining and raising the motivation of the worker.

[0017] According to the invention described in claim 2, the walls located on the left and right sides are provided with curved eaves portions that are bent toward the inside of the work area, so that an air curtain air flow can be formed that is straightened while preventing leakage to the outside by following the inner surface of the curved eaves portions.

[0018] According to the invention described in claim 3, the hood main body is provided with an opening / closing lid that is pivoted to the front edge side of the top plate and is located at the opening, and can freely open and close the central blank area formed between the left and right wall bodies and the front edge of the top plate.Therefore, by keeping the lid covered to cover the central blank area while work is continuing, the required exhaust air volume can be reduced, and when cleaning, the lid can be opened to ensure a wider cleaning work area and allow the cleaning work to be carried out smoothly.

[0019] According to the invention described in claim 4, the slit plate is provided with a sliding door structure that makes the amount of forced exhaust by the pull mechanism variable. Therefore, by sliding the position of the movable slit plate, the amount of forced exhaust via the pull mechanism can be fine-tuned to suit the situation. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is an overall perspective view showing an example of the present invention with the opening / closing cover closed; [Diagram 2] FIG. 2 is an overall perspective view showing the example shown in FIG. 1 with the opening / closing cover open. [Diagram 3] FIG. 2 is a front view corresponding to FIG. 1 with the foot switch omitted. [Figure 4] FIG. 4 is a longitudinal sectional view taken along line AA in FIG. 3 . [Diagram 5] FIG. 5 is an enlarged schematic diagram of a region B surrounded by a solid line in FIG. 4 . [Figure 6] Left side view corresponding to Fig. 3 . [Figure 7] FIG. 3 is a plan view corresponding to FIG. [Figure 8] FIG. 7 is a longitudinal sectional view taken along line BB in FIG. 6 . [Figure 9] Bottom view corresponding to Fig. 3. [Figure 10] FIG. 9 is a longitudinal sectional view taken along the line CC in FIG. 8 . [Figure 11] FIG. 9 is a longitudinal sectional view taken along the line DD in FIG. 8 . [Figure 12] FIG. 4 is a schematic enlarged view of the cross-sectional structure of the essential parts, excluding the slit holes, of an example in which the slit plate shown in the solid-line enclosed area A in FIG. 3 is used as a sliding door structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Fig. 1 is an overall perspective view showing an example of the present invention with the opening / closing cover closed, and Fig. 2 is an overall perspective view showing the example shown in Fig. 1 with the opening / closing cover open. Fig. 3 is a front view corresponding to Fig. 1 with the foot switch omitted, and Fig. 4 is a vertical cross-sectional view taken along line AA in Fig. 3.

[0022] According to these drawings, the entire push-pull type exhaust hood 11 is composed of a hood body 12 having a horizontal work platform 13, which is substantially rectangular in plan view and surrounded by walls 14 on all four sides, an opening 23 on its upper surface, a work area 26 equipped with an indirect lighting LED 27 having a push mechanism 24 and a pull mechanism 25 that form an air curtain airflow C from the front edge 23a of the opening 23 toward the rear edge 23b as shown in Fig. 4, and a support leg 42 that integrally supports the hood body 12. Note that reference numeral 57 in the drawings denotes an indicator light that indicates whether the push-pull type exhaust hood 11 is energized or not.

[0023] Of these, the walls 14 surrounding the horizontal work platform 13 on all four sides are arranged with their respective wall heights determined to provide a gentle forward slope 23 with respect to the opening 23. That is, the walls 14 are composed of a hollow front wall 15 having a hollow section 15a therein and disposed in the longitudinal direction on the front end face 13a side of the horizontal work platform 13, a rear wall 16 erected on the rear end face 13b side of the horizontal work platform 13, a left wall 17 erected on the left end face 13c side of the horizontal work platform 13, and a right wall 18 erected on the right end face 13d side of the horizontal work platform 13.

[0024] The hollow front wall portion 15 is positioned such that the longitudinal direction of the front end face 13a of the horizontal work table 13 is butted against the longitudinal direction of the rear side central height portion, and the rear wall portion 16 is positioned such that its height above the horizontal work table 13 is approximately 8 times the height of the hollow front wall portion 15 above the horizontal work table 13, assuming that the height of the hollow front wall portion 15 above the horizontal work table 13 is 1.

[0025] As is clear from the left side view of Figure 5, the left wall portion 17 and the right wall portion 18 are formed to have a shape roughly resembling a right-angled triangle, with horizontal sides 17a, 18a of a length corresponding to the depth of the horizontal workbench 13, and hypotenuses 17b, 18b corresponding to the height of the hollow front wall portion 15 above the horizontal workbench 13 and the height of the rear wall portion 16.

[0026] For this reason, the opening 23 provided on the upper surface of the work area 26 is highest on the rear wall portion 16 side and lowest on the hollow front wall portion 15 side, and as a result, the respective oblique sides 17b, 18b of the left wall portion 17 and the right wall portion 18 slope downward toward the front from the rear wall portion 16 side toward the hollow front wall portion 15 side, so that the overall arrangement presents a gentle forward slope 23 defined by the oblique sides 17b, 18b of the left wall portion 17 and the right wall portion 18.

[0027] The push mechanism 24 of the hood body 12 is configured to include a plurality of air supply fans 29 that are incorporated into the hollow front wall 15 side, which is the front wall 14, and are arranged to freely force air in the direction of the work area 26. Explaining this with reference to Fig. 5, which is an enlarged schematic view of the solid-line enclosed area B in Fig. 4, the hollow front wall 15 has a recess 32 in the length direction on the bottom 31 side, and a plurality of air supply fans 29, for example, six in total as shown in the bottom view of Fig. 9, are installed through the recess 32, and forced air can be freely supplied into the hollow front wall 15 through ventilation holes 32a drilled in the recess 32 shown in Fig. 5 where the air supply fans 29 are located.

[0028] Furthermore, in the longitudinal direction of the back plate portion 33 located above the horizontal work table 13, which is abutted against the hollow front wall portion 15 via the front end face 13a, a plurality of air supply holes 33a are drilled for sending air pressurized from each air supply fan 34 shown in FIG. 5 through the hollow portion 15a toward the work area 26, and forced air supply toward the work area 26 can be freely formed via these air supply holes 33a.

[0029] On the other hand, the pull mechanism 25 provided in the hood main body 12 is configured to freely draw air from the direction of the work area 26 via an exhaust duct 55 shown in Fig. 4 equipped with an exhaust fan (not shown) capable of forcibly exhausting air from the exhaust port 39a shown in Figs. 1 and 7 provided in a top plate 39 covering the upper opening 38a side of an exhaust path 38 secured between the rear wall 16, which is the rear wall 14, and a slit plate 34 erected inside the rear wall 16, as shown in Fig. 4. Note that reference numeral 39b in Fig. 7 denotes a screw hole used when screwing and fixing the position around the exhaust port 39a via a flange portion (not shown) provided in the exhaust duct 55 shown in Fig. 4.

[0030] In this case, the slit plate 36 separating the working area 26 and the rear wall 16 may be a fixed one, but is preferably provided with a double-layer sliding door structure so that the amount of forced exhaust by the pull mechanism 25 can be variably adjusted. To explain this with reference to Fig. 12, which shows a schematic enlarged cross-sectional structure of the essential parts of the slit plate 36 shown in Fig. 3, except for the slit holes shown in the area A enclosed by solid lines, the slit plate 36 is arranged such that the fixed slit plate 36a on the front side and the movable slit plate 36b on the rear side are positioned so that the slits 37 holes of the fixed slit plate 36a face each other, and the gripping screw 37 is screwed into the movable slit plate 36b side through the long hole 36 provided in the fixed slit plate 36a, thereby changing the relative positions of the slit holes 35, 35 that face each other within the allowable range of the long hole 36, so that the amount of forced exhaust through the pull mechanism 25 can be finely adjusted according to the situation.

[0031] In addition, in the work area 26, indirect lighting LEDs 27 consisting of LED tape lights 28 are arranged on the inner edges of the opening 23 on all four sides, as shown in Figures 4, 8, 10, and 11, so that the horizontal workbench 13 in the work area 26 can be illuminated with just the right amount of indirect light without glare.

[0032] The left wall 17 and the right wall 18 constituting the wall body 14 may have the oblique sides 17a, 18a formed as open ends, but from the viewpoint of forming a more preferably rectified air curtain air flow C, it is preferable to provide curved eaves 19 that are curved so as to bulge out from the oblique sides 17a, 18a toward the inside of the work area 26 so as to face each other, as shown in Fig. 2. In this case, it is preferable that the curved eaves 19 are integrally formed such that the left and right portions close to the rear wall 16 are long eaves 19a and the remaining left and right portions are short eaves 19b, and are disposed to form a central blank area 20 between the front edge 40 of the top plate 39 and the long eaves 19a, 19a.

[0033] Moreover, when the central blank area 20 is formed, it is preferable to arrange an opening / closing lid 51 for opening and closing the central blank area 20 by pivoting it on the front edge 40 side of the top plate portion 39 via a hinge 52 having a structure for maintaining the opening / closing lid 51 upright at 90 degrees to the surface direction of the top plate portion 39. In this case, the opening / closing lid 51 may be made of an opaque resin material, but if design is important, it is preferable to use one made of a gray-smoke semi-transparent acrylic resin material or other transparent resin material. The reference numeral 53 in the figure indicates a handle used when opening and closing the opening / closing lid 51.

[0034] On the other hand, the support leg portion 42 comprises a pair of left and right supports 42, 42 having an approximately L-shape that supports the hood main body portion 12 by integrally connecting a vertical support portion 42a and a horizontal support portion 42b having adjusters 43 at the front and rear, a side panel portion 44 that is fixed to and reinforces the area between the vertical support portion 42a and the horizontal support portion 42b so as to partially cover the area, a control board storage box 48 installed on the rear side, and a blind panel 45 for concealing the control board storage box 48, and the entire portion is formed to provide a knee hole 56 into which the knees of an operator sitting in a chair can be placed.

[0035] Also, a foot switch 47 is provided on the support leg 42, which can freely control the ON / OFF of the indirect lighting LED 27 and the piano sound melody when the push mechanism 24 and the pull mechanism 25 are started and stopped, and can freely control the ON state of the indirect lighting LED 27 while work is continuing. Moreover, the indirect lighting LED 27 is installed so that it can be notified by controlling it to flash yellow when a predetermined trouble occurs, such as a failure of the air supply fan 34. The reference numeral 48 in the drawing indicates a speaker for playing the piano sound melody.

[0036] Next, the operation and effect of the present invention having the above configuration will be described. At the time of starting, the foot switch 47 is turned ON after confirming that the indicator lamp 57 is lit. By turning the foot switch 47 ON, the indirect lighting LED 27 flashes for a short time and an appropriate piano melody is played for a short time through the speaker 48, and at the same time, a start signal is output to the air supply fan 29 constituting the push mechanism 24 and the exhaust fan (not shown) provided in the exhaust duct 55, which start each of them. After that, the indirect lighting LED 27 will continue to be lit until the foot switch 47 is turned OFF.

[0037] That is, the hood body 12 is provided with a work area 26 equipped with a push mechanism 24 and a pull mechanism 25 that form an air curtain air flow C that flows from the leading edge 22a of the opening 22 toward the trailing edge 22b, as shown in FIG. 4, so that workers can smoothly carry out necessary experimental work, etc. in a safe and secure work environment provided by the air curtain air flow C.

[0038] In addition, the work area 26 is formed by determining the height of each of the four walls 14 on each side relative to the opening 22 and providing a gentle forward slope 23, so that an open and clear work environment can be obtained by eliminating oppressive view obstructions such as conventional lift-up sash windows.

[0039] Moreover, the work area 26 is equipped with an indirect lighting LED 27 provided near the opening 22, so that it is lit up with a gentle, non-glare light as if illuminating a pianist shining on a stage.Furthermore, since it is equipped with a knee hole 56, the worker can smoothly carry out the necessary work while sitting in a chair and in a piano playing position, being stimulated by his / her sight and hearing, and maintaining high motivation.

[0040] In other words, the support leg 42 is provided with a foot switch 47 which can freely control the ON / OFF of the indirect lighting LED 27 and the piano melody via the speaker 48 when at least the push mechanism 24 and the pull mechanism 25 are started and stopped, and can also freely control the ON state of the indirect lighting LED 27 while work is continuing, so that the worker can safely and securely carry out the necessary work with good operability and increased motivation even when his or her hands are full.

[0041] Furthermore, in the illustrated example, when a curved eaves portion 19 is provided on the left wall portion 17 and the right wall portion 18, which are the walls 14 located on the left and right sides, and which are curved toward the inside of the work area 26, a more suitably straightened air curtain air flow C can be formed by guiding the air along the inner surface of the curved eaves portion 19 to prevent it from leaking out.

[0042] Furthermore, if the hood body 12 is provided with an opening / closing lid 51 that is pivoted on the front edge 40 side of the top plate 39 and can freely open and close the central blank area 20 that is located at the opening 22 and is formed between the left wall 17 and the right wall 18, which are the left and right wall bodies 14, and the front edge 40 of the top plate 39, the lid can be left in place to cover the central blank area 20 as shown in Figure 1 while work is in progress, thereby reducing the required exhaust air volume, and by opening the lid when cleaning, cleaning work can be carried out more smoothly.

[0043] Furthermore, when the slit plate 34 is provided with a sliding door structure that makes the amount of forced exhaust by the pull mechanism 25 variable as shown in FIG. 12, the amount of forced exhaust via the pull mechanism 25 can be finely adjusted according to the situation by sliding the position of the movable slit plate 34b.

[0044] On the other hand, when necessary work is interrupted or finished, the foot switch 47 can be turned OFF to ensure that the indirect lighting LED 27 is turned off after a short blink of the indirect lighting LED 27 and a short melody is played, thereby eliminating the problem of forgetting to turn off the switch as in the past and further improving the energy saving effect.

[0045] The present invention has been described above based on the illustrated examples, and the specific structure is not limited to these. For example, the slit plate 34 may be a fixed one-piece structure. The left wall 17 and the right wall 18 may be arranged without providing the curved eaves 19. Furthermore, the control board in the control board storage box 46 may be provided with a function that can notify the worker, for example, by making the indirect lighting LED blink yellow when a failure occurs in the air supply fan 29 or other electrical systems. The air curtain air flow C formed in the present invention is naturally generated under a condition in which the inside of the work area 26 is isolated from the outside while taking in a certain amount of conditioned air by making the total amount of air supplied from the air supply hole 33a of the hollow front wall 15 generated by the air supply fan 26 constituting the push mechanism 24 smaller than the total amount of air exhausted by the air exhaust path 38 through the slit plate 34 constituting the pull mechanism 25. The push-pull type exhaust hood 11 of the present invention preferably has a maximum width of 1200 to 1800 mm, a maximum depth height of approximately 1180 mm, a maximum front height of approximately 800 mm, and a maximum depth length of approximately 750 mm, but can be provided without being limited to these sizes as desired. [Explanation of symbols]

[0046] 11 Push-pull type exhaust hood 12 Hood body 12a Left side 13 Horizontal workbench 13a Front end surface 13b Rear end surface 13c Left end surface 13d Right end surface 13a Opposite end face 14 Wall 15 Hollow front wall 16 Rear wall 17 Left wall 17a Horizontal edge 17b hypotenuse 18 Right wall 18a Horizontal edge 18b hypotenuse 19 Curved eaves 19a Long eaves 19b Short eave part 20 Central blank area 22 Opening 22a leading edge 22b Trailing edge 23 Gentle forward slope 24 Push mechanism 25 Pull mechanism 26 Work Area 27 LED for indirect lighting 28 LED strip light 29 Air supply fan 31 Bottom plate part 32 Depression 32a Ventilation hole 33 Back plate part 33a Air supply hole 34 Slit plate 34a Fixed side slit plate 34b Movable side slit plate 35 Slit 36 long hole 37 Picking screw 38 Exhaust duct 38a Upper opening surface 39 Top plate 39a Exhaust port 39b Spiral hole 40 Leading Edge 42 Support section 42a Vertical support section 42b Horizontal support section 43 Adjuster 44 Side plate part 45 Privacy Panel 47 Control board storage box 48 Speakers 51 Opening and closing lid 52 Hinge 53 Handle 55 Exhaust Duct 56 Neil Hall 57 Indicator light C Air curtain air flow

Claims

1. a hood body portion having a horizontal work platform having a substantially rectangular shape in plan view, surrounded on all four sides by walls, with an opening on the upper surface thereof, and a work area provided with an indirect lighting LED and equipped with a push mechanism and a pull mechanism capable of freely forming an air curtain air flow from the front edge side of the opening toward the rear edge side; and a support leg portion that integrally supports the hood body portion, The walls are arranged to correspond to each other and have wall heights determined so as to provide a gentle forward inclination surface with respect to the opening, The push mechanism is configured to include a plurality of ventilation fans that are incorporated in the front wall and are freely arranged to forcibly deliver air toward the work area, The pull mechanism is configured to freely draw air from the direction of the work area through an exhaust duct that can freely forcibly exhaust air from an exhaust port provided in a top plate portion that covers an upper opening side of an exhaust passage secured between the rear wall body and a slit plate erected inside the wall body, A push-pull type exhaust hood is characterized in that the support leg side is provided with a foot switch that can freely control the ON / OFF of the indirect lighting LED and the piano melody at least when the push mechanism and the pull mechanism are started and stopped, and can control the ON state of the indirect lighting LED while work is continuing.

2. 2. The push-pull type exhaust hood according to claim 1, wherein at least the wall bodies positioned on the left and right sides have curved eaves portions that are curved inwardly of the work area.

3. 3. The push-pull type exhaust hood according to claim 1 or 2, wherein the hood main body portion is provided with an opening / closing cover that is pivotally supported on the front edge side of the top plate portion and that is located in the opening and that can freely open and close a central blank area formed between the left and right surrounding walls and the front edge of the top plate portion.

4. 3. The push-pull type exhaust hood according to claim 1, wherein the slit plate has a sliding door structure that allows the amount of forced exhaust by the pull mechanism to be varied.

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