JP2010094603A - Draft chamber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a draft chamber the air current in whose workroom is made excellent by preventing the retainment of air in the workroom of the conventional draft chamber. <P>SOLUTION: A raising/lowering door (a sash window) of the draft chamber is inclined as shown in Fig.1(B) of the selected figure and the length of a baffle panel is reduced, so that the air current in the workroom is made excellent as shown in Fig.1. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

    The present invention relates to a draft chamber, and more particularly to a draft chamber characterized in that the air flow in the working chamber of the draft chamber is improved.

    As is well known, the draft chamber is intended to prevent the danger of workers due to harmful gases and particles generated during experiments using chemicals and the like. In other words, it is a device for enclosing, discharging, and removing harmful substances such as gas and particles generated during the experiment. Therefore, the draft chamber has a working chamber that covers a portion that performs work on the workbench, and is provided with an exhaust passage and an exhaust port for exhausting gas in the working chamber and simultaneously discharging and removing dangerous substances. .

    The draft chamber has an opening for performing an experiment, and air is discharged from the opening for work through the exhaust passage through the exhaust passage, and the exhaust passage is passed through the working chamber. An air flow is generated through the exhaust port.

    3 and 4 are schematic views of a conventional draft chamber, and at the same time, show the state of airflow.

    In these drawings, 20 is a draft chamber, 21 is a work table, and the upper part thereof is a work chamber 22. A plate-like member 24 called a baffle panel is attached in front of the rear surface 23 of the draft chamber 20, and an exhaust passage 25 is formed between the rear surface 23 of the draft chamber and the baffle panel 24. An exhaust port 26 is formed in the upper part of the exhaust path 25.

    A slight gap 27 is provided between the lower end of the baffle panel 24 and the work table 21, and the air on the work table 21 flows into the exhaust path 25 through the gap 27 and rises up the exhaust path 25 to the exhaust port. 26 is discharged.

    In the conventional draft chamber shown in FIG. 3, the baffle panel 24 is composed of an upper panel 24A and a lower panel 24B, and a constant gap 28 is formed between the panel 24A and the panel 24B. A constant gap 29 is also formed between the upper end face of 24A and the ceiling.

    Therefore, in addition to the gap 27, air is exhausted from the gap 28 between the upper panel 24A and the lower panel 24B and the gap 29 between the upper panel 24A and the ceiling.

    On the other hand, the left and right end portions of the upper panel 24A and the lower panel 24B are in close contact with the left and right side wall surfaces of the draft chamber, and there is no gap.

    A sash (elevating door) 30 is provided on the front surface of the draft chamber 20, and is configured such that when the experiment is performed, the sash 30 can be opened to perform work.

    Here, in FIG. 3, (A) shows the state of the airflow when the sash 30 is opened for work, and (B) shows the state of the airflow at that time with the sash 30 closed.

    FIG. 4 is a diagram showing another conventional draft chamber. In this conventional draft chamber, in addition to the upper panel 24A and the lower panel 24B, the baffle panel 24 is provided with a panel (an inclined panel) 24C that is inclined near the ceiling. 31 is formed.

    Also in the conventional example shown in FIG. 4, the left and right end portions of the upper panel 24A, the lower panel 24B, and the inclined panel 24C are arranged in close contact with the left and right side wall surfaces of the draft chamber, and a gap is formed between the left and right end surfaces of each panel. It has not been.

    Therefore, in addition to the gaps 27 and 28, the gas is exhausted from the exhaust port 26 through the exhaust path 25 from the gap 31.

The draft chamber of this conventional example is in an air current state as shown in FIG.
In such a draft chamber, the air in the work chamber 22 is discharged from the work chamber 22 through the exhaust passage 25 through the exhaust port 26 as described above. As a result, harmful gases and harmful particles generated by the experiment are discharged and removed.

    In order to ensure such safety and to be able to conduct experiments in a preferable state, it is necessary to ensure an air flow with little turbulent flow generated inside. Moreover, for example, it is desirable to obtain a stable flow with a substantially constant flow rate at each location of the airflow flowing into the working chamber during the experiment. In other words, when the flow velocity or the like is not uniform, turbulent flow occurs, which causes a large turbulence in the flow, which is not preferable. Therefore, the conventional draft chamber as shown in FIG. 3 and FIG. 4 is devised so that the arrangement position (height) of the gaps 27 and 28 in the baffle panel, the size of the gap, etc. are appropriate. ing.

    However, the conventional draft chamber configured as shown in FIG. 3 and FIG. 4 has a considerably lower flow velocity along the inner wall (working chamber side) of the side surface of the draft chamber and slightly less than the inner side surface of the draft chamber. On the contrary, it was found that the flow rate was large at the distant place. Moreover, it has been clarified that the flow velocity is large at regular intervals from the point where the flow velocity becomes large toward the center, and that the constant flow velocity is small near the center.

    It was also observed that due to this phenomenon, there was a change in the flow velocity especially in the horizontal direction in the working chamber, and this caused turbulent flow and slight backflow from the working chamber.

    The draft chamber described in Japanese Patent Application No. 2007-144862 filed by the applicant of the present application is conceivable as a draft chamber that solves the above-described problems, makes the flow in the opening uniform, and enables efficient exhaust. .

    The above-described draft chamber forms an exhaust path between the draft chamber and the baffle panel arranged along the back surface thereof, and thereby air in the laboratory on the experimental bench passes through this exhaust path from the exhaust port provided at the top. The baffle panel is composed of a plurality of panels (for example, the upper panel, the middle panel, and the lower panel in order from the exhaust port side to the workbench side), and the ceiling of the draft chamber There are gaps between the upper wall of the part and the upper panel, between each panel and between the lower panel and the workbench, and also between the side wall of the draft chamber and the left and right edges of each panel. It is provided.

    In the draft chamber of the above-mentioned application, an air flow flowing along the side wall surface of the draft chamber is formed by forming a gap between the left and right end portions of the baffle panel forming the exhaust passage and the left and right side wall surfaces of the draft chamber. By directing to this exhaust passage directly from this gap, the flow velocity along the side wall surface, which was low in the conventional example, is increased, thereby suppressing the flow rate at a position slightly away from the side wall surface. The flow rate is made uniform. In other words, the flow rate at the part where the flow rate is large from the position slightly away from the side wall surface of the draft chamber to the inner side in the horizontal direction is suppressed, thereby reducing the difference in flow rate from the central part where the flow rate is small. The horizontal flow velocity of the airflow flowing from the chamber opening can be made uniform.

    Further, the draft chamber of the above application is characterized in that a baffle panel provided for forming an exhaust passage is formed on the back surface of the draft chamber, and a rectangular opening extending in the horizontal direction is provided at the center thereof.

    The draft chamber of the said application is the structure shown in FIG. 5, FIG. Of these FIGS. 5 and 6, FIG. 5 is a front view of the opening portion of the draft chamber, and FIG. 6 is a sectional view.

    In these drawings, 31 is a draft chamber, 32 is a work table, 33 is a work room, and a baffle panel 34 is disposed on the back side of the draft chamber 31 behind the work chamber. An exhaust path 38 is provided between the baffle panel 34 and the rear surface of the draft chamber behind the baffle panel 34, and an exhaust port 39 is provided above the exhaust path 38. That is, except for the configuration of the baffle panel 34, the configuration is substantially the same as the draft chamber shown in FIGS.

    In the draft chamber 31, a baffle panel 34 provided on the back side thereof is composed of three panels, an upper panel 34A, a middle panel 34B, and a lower panel 34C, as shown in FIGS. A gap 35 is formed between the upper panel 34C and the lower panel 34C, a gap 36 is formed between the middle panel 34B and the lower panel 34C, and a gap 37 is formed between the upper panel 34A and the middle panel 34B. A gap 37a is also formed between the upper panel 34A and the ceiling.

    Further, a gap 41 is also formed between the left and right ends of the upper panel 34A, the middle panel 34B, and the lower panel 34C and the side wall 31a of the draft chamber 31.

    Further, as shown in FIG. 5, the draft chamber 31 has an opening 40 formed in the center portion of the paffle panel 34. Specifically, an opening 40 as shown is provided at the upper end of the lower panel 34C.

    As a result, in the draft chamber 31, the airflow flowing along the inner surface of the side wall 31 a out of the airflow that intrudes from the opening flows into the exhaust path from the gap 41. The air flowing into the working chamber through the lower gap 35, the central gap 36, the upper and lower gaps 37a and 37 of the upper panel 34A, the left and right gaps 41, and the opening 40 of the lower baffle panel 34C, as shown in FIG. Flowing.

    In this way, this draft chamber accelerates the flow velocity by allowing the air flow flowing along the side wall surface to flow into the exhaust passage from the gap 41, thereby preventing the flow velocity inside the flow from becoming large. Furthermore, the flow velocity in the center is relatively uniform.

    Furthermore, by forming the rectangular opening 40 in the central portion of the baffle panel 34, the central portion of the airflow flowing into the working chamber described above flows through the opening 40 through the opening 40 and flows into the exhaust path from the exhaust port. Since it is discharged, its flow rate becomes faster.

    However, as a result of repeating the experiment in the draft chamber configured as shown in FIGS. 5 and 6, it was found that the air flow in the working chamber was as shown in FIG. Among such flows, the flow on the back surface of the open / close door (shutter) is a flow 40a. Therefore, a certain amount of air stays in the portion A on the back surface of the door, which is not preferable. This phenomenon is generally called a rolling phenomenon.

    The conventional draft chamber generally has a structure in which the baffle panel extends downward including the draft chamber of the above-mentioned application (draft chamber shown in FIGS. 5 and 6). Thereby, it has the effect | action which suppresses the variation in the control wind speed of the opening part of the draft chamber of a baffle panel. However, there is a problem that a part of the flow that is not sucked into the discharge path (not discharged from the discharge path) similarly causes a rolling phenomenon.

    As described above, the conventional draft chamber is liable to cause a rolling phenomenon, and air stays there.

    Further, in the conventional draft chamber as shown in FIGS. 5 and 6, when the door is lowered relatively downward, as shown in FIG. 8, a flow descending from above is generated along the inner surface of the door. May stay in the vicinity of the lower part of the door as shown in FIG. 8 due to the air flowing in due to the slight opening of the lower part of the door. The air flow staying in the vicinity of the lower portion of the door may leak out of the draft chamber due to the operation of the operator at the draft chamber opening.

    The present invention provides a draft chamber in which a rolling phenomenon is prevented from occurring and air is not retained.

    The draft chamber of the present invention has a configuration in which the front surface portion is inclined and has an inclined surface that can be laid rearward toward the upper side. In other words, the front portion was inclined so that the interval between the working chambers was shortened upward.

    As a result, the flow of air in the upper part of the draft chamber is changed to make the flow less likely to stay, and the rolling phenomenon is less likely to occur.

    In the draft chamber of the present invention, the inclination angle θ of the front portion is preferably about 7 ° as in Example 1 described later. However, if the inclination angle θ is in the range of 5 ° <θ <10 °, the object of the present invention can be achieved.

The draft chamber of the present invention is characterized in that the front surface portion is inclined as described above, and the baffle panel is provided only at the upper portion near the discharge port.
As a result, the flow of air rising along the work chamber side surface of the baffle panel, which is one of the causes of the conventional rolling phenomenon, becomes a flow along the rear surface of the draft chamber, and the baffle panel provided at the top It is discharged through the exhaust path between the rear surface and the occurrence of the rolling phenomenon can be almost completely prevented.

    Further, the draft chamber of the present invention is characterized in that a stay prevention plate extending substantially horizontally toward the work room side is provided at the lower end portion of the lifting door provided on the front surface.

    By having this feature, the direction of the air flow descending along the inside of the elevator door is changed to the work chamber side, and the above-described descending air flow due to the air flow flowing in from the outside and flowing along the work table surface is generated. Retention can be prevented.

    In addition, this retention prevention plate can obtain the same effect by applying it to a draft chamber whose front surface is inclined, and the same effect can be obtained when it is applied to other draft chambers such as a draft chamber whose front surface is vertical. It is done.

    Further, the stay prevention plate may be disposed horizontally as in Example 2 to be described later, but may be inclined in either the vertical direction with respect to the horizontal direction. In that case, it is preferable to incline ± 10 °.

    The draft chamber of the present invention has a discharge path formed between the back surface and the baffle panel by tilting the lift door (sash) and shortening the length of the baffle panel (length in the vertical direction). The effect that the rolling phenomenon which generate | occur | produces in the back upper part of a raising / lowering door by the point which located the opening | mouth upwards hardly occurred is produced.

    Furthermore, by providing a stay prevention plate extending substantially horizontally at the lower end of the lift door (sash), it is possible to prevent the stay from occurring in the lower part of the back surface of the lift door (sash).

    Embodiments of the draft chamber of the present invention will be described based on examples shown in the drawings.

    1A and 1B show a first embodiment of the draft chamber of the present invention, in which FIG. 1A is a front view and FIG. 1B is a cross-sectional view.

    In these drawings, 1 is a draft chamber body, 2 is a work table, 3 is a back plate, 4 is a lifting door (sash), 5 is a work chamber, 6 is a baffle panel, and 7 is a discharge port.

    The draft chamber 1 of the first embodiment is characterized in that the elevating door (sash) 4 is not positioned on a vertical plane but is inclined with respect to the vertical plane. Specifically, it is arranged on a surface located rearward of the vertical surface as it goes upward.

    By having this feature, the space above the draft chamber 1 is reduced, the vicinity of the back surface 3 is raised, and the retention of air on the back surface of the front elevating door (sash) 4 is reduced at the ceiling portion. It becomes possible.

    The second feature of the draft chamber of the first embodiment is that the configuration of the baffle panel 6 is different from the conventional one.

    That is, the baffle panel that has been extended to the vicinity of the conventional work table is set to a length between the work table and the ceiling portion or to an upper position as shown in FIG.

    Thus, conventionally, the air rising along the work chamber side surface of the baffle panel flows into the discharge path between the baffle panel 6 and the back surface 3 and is discharged from the discharge port, thereby reducing the flow toward the ceiling. Retention at the upper back of the elevator door was reduced to suppress the rolling phenomenon.

    In particular, as shown in FIG. 1B, the first embodiment is an embodiment having both the features of tilting the elevating door (sash) and the point that the baffle panel is configured as described above. .

    As a result, the air flow as shown in FIG. 1 (B) is obtained, and there is no stagnation on the working room side (portion corresponding to A in FIG. 7) of the lifting door, that is, a good draft chamber in which no rolling phenomenon occurs. You can get none.

    In Example 1, the degree of inclination of the elevator door, that is, the inclination angle (θ) from the vertical plane is about 7 °. By setting the inclination angle θ of the lift door to about 7 °, it is most preferable because it is possible to prevent the air flow from staying and to easily work in the work chamber.

    However, there is no practical problem as long as it is within the range of 5 ° <θ <10 ° without being limited to θ≈7 °. If θ <5 °, the effect of suppressing the retention is small, which is not preferable. On the contrary, when θ> 10 °, the stay can be suppressed, but this is not preferable because the working chamber becomes narrow and it is difficult to work.

    In the draft chamber of the first embodiment, a gap may be provided between both ends of the baffle panel and the side wall as in the draft chamber of the application.

    FIG. 2 is a view showing a main part of a second embodiment of the draft chamber of the present invention.

    As already described with reference to FIG. 8, the air flow descending along the back surface of the lift door (sash) flows from the outside through the opening between the lower end of the lift door (sash) and the work table. The air flow as shown in FIG. 8 is merged with the flow, and stagnation occurs in this portion.

    An example in which this stagnation does not occur is Example 2.

That is, the draft chamber of the second embodiment is provided with the stay prevention plate 9 extending substantially horizontally on the side of the working chamber 5 at the lower part of the elevating door 4 as shown in FIG.
By providing this stay prevention plate 9, the air flow descending along the inner surface of the elevating door (sash) 4 is bent in the horizontal direction (horizontal direction) and is almost in the same direction as the air flow from the outside flowing in from the opening. And no stagnation occurs.

    The retention prevention plate, which is the main part of the second embodiment, is used in the draft chamber of the first embodiment shown in FIG. 1, but the normal draft chamber (the elevator door as shown in FIG. 3 is inclined). It may be used for an undrafted draft chamber), and the same effect can be obtained.

    In the second embodiment, the stay prevention plate is attached horizontally, but if it is within a range of ± 10 ° with respect to the horizontal plane, the stay prevention effect can be sufficiently obtained even with the vertically inclined arrangement.

The present invention relates to a draft chamber used in a chemical experiment or the like in which harmful substances (gas) are generated, and ascends and descends to make the air flow in the working chamber good by making the flow velocity flowing into the working chamber substantially equal. The door (sash) is inclined and only the baffle panel upper baffle panel is used, thereby preventing the harmful gas from flowing out to the outside and allowing the work room to perform well.

The figure which shows the draft chamber of Example 1 of this invention. The figure which shows the structure of the retention prevention board provided in the lower end part of the raising / lowering door (sash) in the draft chamber of Example 2 of this invention. Diagram showing the structure and air flow of a conventional draft chamber The figure which shows the structure of other conventional draft chambers, and an air flow Still another conventional draft chamber front view The figure which shows the structure and air flow of the draft chamber shown in FIG. The figure which shows the condition of the stay in the prior art example shown in FIG. The figure which shows the situation of the residence in the lower end part of the raising / lowering door (sash) of the conventional draft chamber

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Draft chamber body 2 Work table 3 Back plate 4 Elevating door 5 Work room 6 Baffle panel 7 Discharge port 9 Retention prevention plate 10 Air flow

Claims (3)

A side, back, and ceiling are provided along the periphery of the workbench, and a work room is formed by providing a lift door on the front, and a baffle panel that forms a discharge path between the back and the back is provided and flows into the work room. In the draft chamber in which a part of the air to be discharged from the lower end of the baffle panel through the discharge path and discharged from the discharge port provided in the ceiling part, the elevating door is inclined upward toward the work room side, A draft chamber characterized in that the lower end of the baffle panel is positioned near the center of the height of the working room. The draft chamber according to claim 1, wherein a retention preventing plate extending in a substantially horizontal direction is provided at a lower end portion of the elevating door toward the working chamber side. A working room is formed by providing a side surface, a back surface, and a ceiling along the periphery of the working room, and a lift door is provided on the front surface, and a baffle panel that forms a discharge path provided along the back surface is provided. In the draft chamber in which a part of the air flowing into the exhaust passage is discharged from the discharge port through the discharge passage, a retention prevention plate extending substantially horizontally toward the work room side is provided at the lower end portion of the lift door. A featured draft chamber.

Images