CZ2010203A3 - Exhaust hood - Google Patents

Abstract

A fume cupboard consisting of a suction box (1) comprising a top wall (11), a rear wall (12), a front wall (13) with a pull-out window (4) mounted in the side walls (14) and a bottom technical part (15) with a worktop ( 151), a suction duct (2) is attached to the rear wall (12) and the top wall (11) of the housing (1), to which a controllable air conditioning system (40) is connected to draw clean air entering the working chamber (3) and to remove harmful substances from the working chamber (3), following the information provided by the sensor inside the working chamber (3), where the pull-out window (4) is fitted with a window ledge (5) on the lower edge (41) of the air supply to the working chamber (3). ), the side walls (14) are fitted with a lateral leading aerodynamic rail (7) on the front edge (141) of the air supply to the working chamber (3) and a set of lower holes (121) is formed on the rear wall (12) above the worktop (151) ), approximately at working height a set of central bores (122) is formed on the rear wall (12) and a plurality of upper bores (111) are formed on the top wall (11), the suction box (1) being on the inlet edge (152) of the worktop (151) fitted with a double leading aerodynamic rail (6). This double run-in aerodynamic strip (6) is composed of a full profile (61) attached to the worktop (151) and a runner (62) forming an air channel (63) where both the full profile (61) and the runner (62) are the side extending outside the housing (1) and the other side extending up to the working chamber (3), the leading edge (62) is mounted above the full profile (61) to which the elements (64) are connected. Leading bar (

Description

(57)

A fume hood comprising an exhaust box (1) comprising an upper wall (11). the rear wall (12). a front wall (13) with a sliding window (4) mounted in the side walls (14) and a lower technical part (15) with a worktop (151). a suction channel (2) is attached to the rear wall (12) and the top wall (11) of the housing (1). connected to a controllable ventilation system (40) for sucking in clean air entering the working chamber (3) and extracting harmful substances from the working chamber (3), based on the information provided by a sensor located inside the working chamber (3), 4) the bottom edge (41) of the air inlet to the working chamber (3) is fitted with a window leading strip (5), the side walls (14) are fitted with a side leading aerodynamic strip on the front edge (141) of the air inlet to the working chamber (3) (7) and a plurality of bottom openings (121) is formed on the rear wall (12) above the worktop (151). approximately at the working height of the open sliding window (4), a set of central openings (122) is formed on the rear wall (12) and a set of upper openings (111) is formed on the top wall (11) near the rear wall (12), the casing (1) is fitted with a double run-in aerodynamic strip (6) at the entrance edge (152) of the worktop (151). such a double run-in aerodynamic bar (6) is composed of a solid profile (61) attached to the worktop (151) and a run-in bar (62) forming an air channel (63). wherein the full profile (61) and the leading strip (62) are led out one side outside the housing (1) and the other extending into the working chamber (3). the leading strip (62) is fitted above the solid profile (61). to which it is connected by elements (64). In the area extending into the working chamber (3), the leading strip (62) is terminated by openings (621).

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Technical field

The invention relates to a fume hood, in particular for laboratory use, to prevent the escape of pollutants from the working space and with the removal of vapors from the working space by an air vent connected to an external exhaust fan or a central air vent.

BACKGROUND OF THE INVENTION

Known hoods are subject to certain standards to prevent leakage - blowing of harmful substances from the hood's working area into the environment. German Patent Application DE 19712975 A1 discloses a fume hood with a working chamber with the removal of harmful substances by means of an air screen, which is blown up through the opening of the working chamber from the underside. Although it is thus possible to improve exhaust safety against external disturbances, it is not possible to prevent heavy gases from accumulating in the lower part of the working chamber or light gases from accumulating above the opening of the working space. From US 2004/0242143 A1 a fume hood is known with a working chamber opened on one side and an air blowing device installed on the open side of the working chamber, the device being installed so that air into the working chamber is blown at an acute angle to the inner surfaces of the side cladding walls and cladding bottom. The disadvantage of this solution is that there is a partial turbulence of air at the inlet edges of the hood and thus accumulation and leakage of pollutants from the working chamber into the surrounding space of the hood. A further disadvantage is that for good ventilation of the working chamber, air must be supplied to the working chamber from another source, which increases production costs. Usual air consumption for well known hoods per 1 m is about 500 m ³ / hour with the sliding window working position. From US 6461233 a fume hood is known which is provided with a simple arc-shaped lead-in at the entrance edge of the worktop. The disadvantage of this simple headboard is that the air entering the working chamber impinges on the sharp lower edge of the worktop and its inlet and flow rate into the working chamber is already braked and comminuted at this sharp lower edge.

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SUMMARY OF THE INVENTION

The known drawbacks of existing hoods are largely overcome by a hood according to the invention consisting of an exhaust box comprising an upper wall, a rear wall, a front wall with a sliding window mounted in the side walls and a lower technical part with a worktop. A suction channel is attached to the rear wall and top wall of the cabinet, to which a controllable air handling system for intake of clean air entering the working chamber and suction of harmful substances from the working chamber is connected, based on information provided by the sensor inside the working chamber. The sliding window is fitted on the lower edge of the air inlet to the working chamber with a window runner, the side walls are fitted with a lateral aerodynamic runner on the lower edge of the air inlet to the working chamber and a set of lower openings above the worktop of the sliding window, a set of central openings is formed on the rear wall and a set of upper openings is formed on the top wall _t near the rear wall. The essence of the invention consists in that the suction box is fitted with a double run-in aerodynamic bar at the entrance edge of the worktop.

The double runner consists of a full profile attached to the worktop and a runner forming an air channel, where both the full profile and the runner are led out of the cabinet on one side and into the working chamber by the other. The leading strip is fitted above the full profile to which it is attached. In the area extending into the working chamber (3), the leading strip is terminated by openings.

The main advantage of the invention is that the use of a double lead-in aerodynamic bar located at the lower edge of the worktop will increase the exhaust air speed on this double lead-in bar, thus preventing the escape of harmful gases into the room.

When using the double runner aerodynamic rail and in combination with the aerodynamic rails used on the side walls and hood windows and in combination with the exhaust openings and the possibility of automatic closing of the window and the hood ventilation control system at the same time working chamber criteria. Due to the lower exhaust air volume, this system can achieve very economical operation. • 4 * 4 * 4 * 4 * 4 * 4 * 4 * 4 * 4 * 4

- .3 fume hoods with a significant reduction in the energy costs of operating the ventilation equipment ensuring the operation of the fume hood.

Overview of pictures

The invention is illustrated in the following figures, wherein:

Giant. 1 shows a front view of the hood with the work window closed

Giant. 2 shows a rear view of the hood

Giant. 3 shows a longitudinal section of the suction cupboard with the sliding window open

Giant. 4 shows a longitudinal section of the suction cupboard with the sliding window closed

Giant. Fig. 5 is a longitudinal sectional view at A-A of Figs. 1 and 4;

Fig. 6 shows a longitudinal cross-section at B-B of Fig. 1 and Fig. 4 - exhaust at the working height of the sliding window from the exhaust box

Giant. 7 shows a view D in FIG. 1 of the back wall of the suction box

Giant. 8 illustrates a flow simulation on a dual aerodynamic bar disposed on a worktop from a suction box

Giant. 9 illustrates a flow simulation on a window aerodynamic bar located at the lower edge of a work-window sliding window

Giant. 10 shows a flow simulation on a side aerodynamic bar located on the side edges of the aspirated housing

DETAILED DESCRIPTION OF THE INVENTION

The fume hood shown in FIGS. 1 to 4 consists of a suction box 1 with a working chamber 3, in which pollutants (contaminated air) are produced during the operation, which are subsequently discharged from the working chamber 3 by means of a suction channel 2 connected to the active ventilation system 40.

The housing 1 consists of an upper wall 11, a rear wall 12, side walls 14, a front wall 13 and a lower technical part 15 comprising a worktop 151 and a set of controls 153, eg light, electricity, media, etc. placed vertically open i! I * + '* *' · ¹ · t * * · · i «1 window 4 with horizontally sliding lenses. An air flow sensor (not shown) is located inside the housing 1 which controls the amount of exhaust air depending on the position of the sliding window. A suction channel 2 is attached to the rear wall 12 and the top wall 11 of the housing 1, which is terminated by a neck 21. (Fig. 3). On the rear wall 12 of the housing 1, a plurality of lower holes 121 of equal diameter are formed above the worktop 151, and a plurality of equally sized central holes 122 are formed approximately equal to the working height of the open sliding window 4 (FIGS. 1 and 7). The bottom openings 121 are formed of seven rows one above the other and are distributed over the entire width of the rear wall 12, the diameter of the openings being about 10 mm. The central openings 122 are not formed over the entire width of the rear wall 12, but are formed near the side walls 14. For each side wall there are four columns of eight rows of central openings 122 whose diameter is about 10 mm (FIG. 7). The bottom openings 121 and center openings 122 provide for faster airflow at the side walls 14 and on the worktop 151, therefore pollutants in the work space 3 do not remain at the side walls 14 and on the worktop 151 but are effectively sucked into the connected exhaust duct 2. the lower openings 121, the central openings 122 and the upper openings 111 ensure uniform removal of contaminants from the entire working space 3. Directional flow of the pollutants exiting the working space 3 through the lower openings 121 into the exhaust duct 2 and the flow direction of the pollutants d leaving the working space 3 to the suction channel 2 is shown schematically in FIGS. 5 and 6.

On the top wall 11 near the rear wall 12 is formed one row of diameter equal sized upper openings 111, having a diameter of about 10 mm (FIG. 7). The flow direction of the pollutants f leaving the working space 3 through the upper openings 111 into the exhaust duct 2 is shown schematically in FIGS. 3,4 and 7.

The formation and arrangement of the upper openings 111 on the upper wall 11, the lower openings 121 and the central openings 122 on the rear wall 12 is here due to the airflow technology and the ingress of dirt leaving the working chamber 3 into the exhaust duct 2 and also to prevent leakage of pollutants. In particular, leaks around the sliding window 4 and the space 30 or 31 below the open window 4 are located on the working chamber 3.

On the front wall 13 of the casing 1, a sliding window 4 is moved in the guide grooves 8, on the lower edge 41 of which there is a window run-in aerodynamic strip 5 which directs t ♦ »t 4 f> <<J '1 5 * í 5 *> * ϊ E »T * * * lit» 1 τ * · 4 ♦ «>» »ΐ E,« «

-5flow of clean air b from the fume hood environment into the working chamber area

3. The window runner 5 also includes a retaining groove 51 which prevents condensate from dripping out of the sliding window 4. The guide grooves 8 are formed in the side runners 7 located on the leading edges 141, the side walls 14. The side walls 14 are formed of sandwich panels (Figs. 5, 6 and 10). The sliding window 4, when opening, slides behind the front cover 9, which is attached to the side walls 14. On the front cover 9 there is a sensor 10 detecting the movement of persons near the sliding window 4. If no persons have been in the space in front of the sliding window 4 , the sensor 10 gives a signal to partially close the sliding window 4, thereby reducing the space 31 between the double runner 6 and the window runner 5 to a height of about 30 mm (FIG. 4). By partially closing the window 4, the consumption of clean air entering the chamber 3 is reduced. In the working cycle during suction of dirt from the working chamber 3 is the technological height of the open sliding window

4, i.e. the open space 30 between the lower runner 62 and the window runner 5, is given by the standard and is about 500 mm (Fig. 3). A simulation of the air flow around the sliding window 5 of the sliding window 4 is shown in Fig. 9.

In order to increase the efficiency of sucking clean air from the outside of the hood into the working chamber 3 and also to prevent the escape of pollutants from the working chamber 3 to the outside through leakage of the sliding window 4 and through space 30 or 31, The leading profile 6. This double leading profile 6 is composed of a solid profile 61 and a lower leading strip 62. The full profile 61 is attached to the worktop 151 .. Both the full profile 61 and the lower leading strip 62 are led outside the housing 1 a The lower runner 62 is fitted above the solid profile 61 to which the elements 64 are attached. The lower runner 62 is terminated over the entire width of the openings 621 in the area extending into the workspace 3. there are fifteen rows and the hole diameter is about 5 mm . An air channel 63 is formed between the full profile 61 and the lower runner 62, creating a faster flow of clean air b from the outside into the chamber 3. The clean air b enters the chamber 3 through the air channel 63 where it is partially divided so that of air b flows through air duct 63 (primary flow) and a portion of air b enters working chamber 3 through orifices 621 (secondary flow). Clean air b,> t t, t. I -,? * 1 111> 4 4 t ♦ »(!;» * * I «» »Ϊ 4 4 4 4 I

4 ♦ * * 1 1 1 1 1 1 1 1 * *

- which enters the working chamber 3 through the openings 621 creates an air curtain (secondary flow) between the window aerodynamic strip 5 of the sliding window 4 and the leading strip 62 to prevent contaminated air from escaping from the working chamber 3 back into the environment (Figs. 3, 4, 8) ). The simulation of the airflow on the double aerodynamic rail is shown in Fig. 8 and the simulation of the airflow on the side aerodynamic rail 7 is shown in Fig. 10.

The technology of the intake of clean air into the working chamber 3 and the exhausting of contaminated air from the working chamber 3 of the hood is based only on the active air flow system by the active air handling system 40 connected to the exhaust duct 2. In terms of operating costs, it is important to ensure that contaminated air is completely discharged from the working chamber 3, but that as little air as possible is introduced into the working chamber from the outside of the hood.

The construction of the aerodynamic rails 6, 7 and 5 located on the worktop 151, on the side walls 14 and on the sliding window 4 ensures uniform and low-turbulent air flow on the walls of the hood 1 and thus prevents the escape of pollutants from the chamber 3 back into the environment. Extraction of pollutants (contaminated air) from the chamber 3 takes place in three levels:

a) Extraction above the worktop 151 prevents the spread of gases and pollutants heavier than air

b) exhaust at working height of the sliding window 4 prevents accumulation of gases and pollutants at the side walls 14

c) suction on the top wall 11 ensures a perfect exhaust of gases lighter than air

According to the standard, the height of the open space 30 is about 500 mm. When the active ventilation system 40 is switched on, clean air begins to enter the working chamber 3 through the air duct 63, through the open space 30 between the sliding window 5 of the sliding window 4 and the lower sliding window 62 and leaks around the sliding window 4. The design of the extractor hood is achieved by the construction of aerodynamic rails on the entrance edges of the exhausted cabinet achieved a reduced air consumption per 1 m of extractor hood with the working position of the sliding window of approx. 350 m ³ / hour.

Claims (3)

PATENT CLAIMS A fume hood comprising an exhaust box (1) comprising a top wall (11), a rear wall (12), a front wall (13) with a sliding window (4) mounted in the side walls (14) and a lower technical part (15) a suction channel (2) is attached to the rear wall (12) and the top wall (11) of the housing (1) to the rear wall (12) and the top wall (11), to which a controllable ventilation system (40) suction of harmful substances from the working chamber (3), based on information provided by the sensor located inside the working chamber (3), where the sliding window (4) is fitted with a window leading strip on the lower edge (41) of air supply to the working chamber (3) (5), the side walls (14) are fitted with a side run-in aerodynamic strip (7) at the front edge (141) of the air supply to the working chamber (3) and a set of bottom plates is formed on the rear wall (12) otvor a plurality of central openings (122) are formed on the rear wall (12), and a plurality of upper openings (111) are formed on the top wall (11) near the rear wall (12) at approximately the working height of the open sliding window (4). ) _? characterized in that the aspirated housing (1) is fitted with a double run-in aerodynamic strip (6) at the inlet edge (152) of the worktop (151). Fume cupboard according to claim 1, characterized in that the double run-in aerodynamic strip (6) is composed of a solid profile (61) attached to the worktop (151) and a run-in strip (62) forming an air channel (63), both the full profile (61) and the leading strip (62) are led out by the outside of the cabinet (1) and the other side extending into the working chamber (3), the leading strip (62) is fitted above the full profile (61) elements (64). Fume cupboard according to claims 1 and 2, characterized in that the leading strip (62) is terminated by openings (621) in the area extending into the working chamber (3).