WO1995014195A1

WO1995014195A1 - Safety workbench

Info

Publication number: WO1995014195A1
Application number: PCT/AT1994/000171
Authority: WO
Inventors: Manfred Wieser
Original assignee: Anthos Labtec Instruments Ges.Mbh
Priority date: 1993-11-16
Filing date: 1994-11-11
Publication date: 1995-05-26
Also published as: DE9400530U1

Abstract

Described is a safety workbench with an enclosure (3) which surrounds the work space (2) of the workbench (1), the bottom of the work space forming the work surface (4). The front (5) of the enclosure has an aperture (6) in front of the work surface, thus permitting access to the work surface. The front wall (7) above the aperture is designed so that it can be opened and is fitted with a viewing window (8). The enclosure is also fitted with a ventilation and air-filtering unit (10, 11, 12, 13, 14) which produces a turbulence-free flow of air from the top of the work space down to the work surface (4) where the air is sucked out again. The front wall (7) of the enclosure extends across the top of the aperture (6), and both the inside (21) and outside (22) surfaces of the front wall extend upwards, and initially outwards at an angle, from the upper edge of the aperture, this outwards-inclined section (24) being followed by a section (28) which extends inwards at an angle.

Description

Safety workbench

The invention relates to a safety workbench with a box enclosing the work space of the workbench, the bottom of which forms the work surface, the work opening on the front side in front of the work surface, and a front wall arranged for opening above the work opening has a viewing window, and with an air filter and ventilation device, which forms a turbulence-free air flow in the work area, directed from above towards the work surface, which is suctioned off in the area of the work area, at least in the area of the front edge and in the area of the rear edge suction openings are provided on the work surface, and air is sucked down through the suction opening provided in the area of the front edge of the work surface during operation, with an air inflow d is accompanied by the work opening, which prevents undesired leakage of substances originating from the work area through the work opening.

Safety cabinets of the aforementioned type (for example DE 38 11 780 AI) are intended for microbiological and biotechnical work, and the safety cabinet is intended to protect workers and the environment from harmful influences of substances, in particular suspended matter, which are released during work. These substances should therefore be prevented from reaching the environment through the work opening when the worker is present. It is already counteracted by the fact that in the work space a turbulence-free air flow is directed from above to the work surface and the air that flows in this way to the work surface of the safety workbench is sucked off again from the work surface area, a tolerance of substances released in the work area; in a largely turbulence-free flow, such substances are only tolerated to a small extent by the flow transversely to the direction of flow and are accordingly removed from the working space with the suction provided. The air inflow through the work opening caused by this suction also acts likewise against the escape of substances from the work space through the work opening into the environment. However, with this inflow of air through the work opening, associated with known safety workbenches of the type mentioned at the outset, in the region of the work opening, in particular at the edges thereof, turbulence occurs, which entails the risk that parts of the air flow present in the work space escape to the outside . For this reason, in known safety workbenches of the type mentioned at the outset, various, sometimes complicated, flow internals have been provided in the region of the working opening in order to prevent flows from passing through the working opening from the inside to the outside. Flow installations of this type require increased structural complexity and can also make the operation of a safety workbench more difficult, for example because they hinder manipulation when working or the view of the structure set up on the work surface. Such flow internals also make it difficult to maintain and maintain them, and such flow internals also cause an increased outlay in terms of production.

It is an object of the present invention to provide a safety workbench of the type mentioned at the outset, in which the disadvantages in terms of structure and operating properties which are present in known safety workbenches of the type in question here, which include the disadvantages mentioned above, are eliminated. and which, with the simplest possible structure, has good operating properties and good security against undesired leakage of substances which are released when working in the safety workbench.

The safety workbench according to the invention of the type mentioned at the outset is characterized in that the front wall of the box adjoining the work opening upwards initially runs obliquely outwards with its inside as well as with its outside from the top edge of the work opening upwards, in which In the operating position of the front wall leaving the working opening open, the plane corresponding to the outside, rising wall surface extends to a suction opening provided in the area of the front edge of the working surface and extending over the entire width of the working surface in its zone adjacent to the working surface meets, and on the section of the front wall that rises obliquely outwards, a section of the front wall that rises inwards follows. With this training, the above-mentioned objective can be met well. Due to the special design of the front wall of the box of the safety workbench adjoining the work opening upward, air flow through the work opening that is largely free of disturbing turbulence is achieved, which means that structurally very simple way of preventing substances from escaping through the work opening is particularly effective. At the same time, this special design of the front wall of the box of the safety workbench practically does not cause any adverse influence on the air flow directed in the work area from above to the work surface, so that due to its lack of turbulence it does not tend to tolerate materials transversely to the direction of flow and also when it meets the air flow coming through the work opening practically does not form any harmful swirls, through which substances from inside the safety workbench could be carried outside. The flow cross section of the air flow directed from above towards the work surface is gradually increased in the region of the section of the front wall that rises inwardly, which has no adverse effect on the turbulence-free character of this air flow, and it becomes in the subsequent section of the front wall that rises outwards the part of the air flow adjacent to the work opening in the work space of the safety workbench directed to the work surface through the inside of this section of the front wall is passed gently and without turbulence past the inside of the work opening for suction in the region of the front edge of the work surface. The relatively low suction effect, which is associated with the above-mentioned air flow passing the inside of the working opening, together with the obliquely outwardly increasing surface of the front wall, causes a uniform air flow on the outside of this front wall section, which air flow flows to the working opening and arrives at the front edge of the work surface, largely without turbulence.

One with regard to the aforementioned flow conditions and An embodiment of the safety workbench according to the invention, which is advantageous in terms of the construction as simple as possible, is characterized in that the upper end of the section of the front wall which rises obliquely inwards, viewed in plan, lies approximately above the lower edge of the section of the front wall which is directed obliquely outwards.

It is further advantageous to obtain a flow of air that is as uniform as possible over the entire extent of the work surface if a suction opening provided at the rear edge of the work surface above the work surface at the lower edge of the rear wall of the work space, which edge at a distance above the level of the work area Work surface is provided. In order to adjust the flow conditions in the work space or on the work surface, it is advantageous if the height of the suction opening provided on the rear edge of the work surface can be changed with a limiting body which is arranged on the rear wall in a height-adjustable manner.

A further advantageous embodiment, which can contribute to the advantageous equalization of the air flow in the area of the work surface by structural symmetry, results from an embodiment which is characterized in that at the top of the suction opening provided at the rear edge of the work surface one of the rear wall of the work ¬ space is provided wedge-like flow guide wall running obliquely downwards into the work space. It is further advantageous to achieve the most uniform possible inflow into the suction opening provided at the rear edge of the work surface if one provides that the wedge-shaped flow control wall at the bottom, approximately, forms a rounding into a suction opening provided at the rear edge of the work surface boundary wall running parallel to the work surface. Structurally and with regard to the adjustability of the suction through the suction opening provided at the rear edge of the work surface, it is advantageous if one provides that the flow directing wall, the rounding and the boundary wall are combined to form a boundary body.

With regard to the front wall, there is a structurally simple and flow-wise favorable solution, which also creates good visibility into the work space, if the sections of the front wall which run upwards at an angle to the work opening are formed by an angled transparent plate.

With regard to the design of the front wall, it is also expedient if it is guided so that it can be moved up and down and can be moved downwards until the work opening is closed, and in this way, with constructional simplicity, simple handling when establishing largely free access to the work space Preparation of work processes, when working in the operating position of the front wall defined by regulations on the size of the work opening and for completely closing the work space.

The invention will now be further explained by means of examples with reference to the drawing, in which examples are shown schematically.

The drawing shows:

Fig.l an embodiment of a safety cabinet designed according to the invention in a view from the front;

2 shows this embodiment in a section taken along the line II-II in Fig.l;

3 shows this embodiment with the front wall pushed up in a view similar to FIG. 1;

4 shows a partial representation of the area at the rear edge of the working surface of this embodiment in a section analogous to FIG. 2, and

5 shows the area of the work surface of another embodiment of a safety workbench according to the invention in a section performed analogously to FIG.

In the embodiment of a safety workbench 1 shown in FIGS. 1 to 4, a box 3 is provided which surrounds the work space 2 of this workbench. The bottom of the box 3 forms the work surface 4. On the front side 5 of the box 3, a work opening 6 is provided in front of the work surface 4, which enables access to the work surface. Above the working opening 6 there is a front wall 7 which is set up for opening and has a viewing window 8, which provides an insight into the working space 2 or onto the working surface 4. This safety workbench 1 is provided with an air filter and ventilation device, which forms a turbulence-free air flow in the working space 2, directed from above towards the working surface 4, which is indicated by arrows 9. To this end, it can also be mentioned that a speed of 0.4 m / s ± 20% is provided for such safety workbenches in accordance with standards for such air flow 9 which are intended for microbiological and biotechnological work. The air filter and ventilation device includes air channels 10, 11, a suction fan 12, a distribution chamber 13 and a high-performance suspended matter filter 14 arranged on the ceiling of the box 3. With this air filter and ventilation device, the air flow 9 becomes in the area of the work surface 4 suctioned, namely through a suction opening 16 provided in the area of the front edge 15 of the work surface 4 and through a suction opening 18 provided in the area of the rear edge 17 of the work surface 4. The suction opening 16 opens into the air duct 10 running under the work surface 4 , which is continued in the air duct 11 running behind the rear wall 19 of the box 3, into which the suction opening 18 opens. The air duct 11 leads to the induced draft fan 12, the outlet of which is connected to a distribution chamber 13 which extends over the entire top wall of the box 3. This ceiling wall is formed by a replaceable, plate-shaped, high-performance suspended matter filter 14. The suction of the air flow through the suction openings 16, 18, which is symbolized by the arrows 9, is accompanied by an air inflow through the working opening 6, which air inflow is indicated by arrows 20. This inflow of air keeps an undesired escape of substances originating from the work area or work space 2 through the work opening 6.

The front wall 7 of the box 3 adjoining the working opening 6 upwards runs both with its inside 21 and with its outside 22 from the upper edge 23 of the working opening 6 upwards initially in section 24, rising obliquely outwards, in the operating position of the front wall 7, which is shown in FIGS. 1 and 2, the plane 26, which runs in accordance with the outside wall surface that rises to the outside, onto the plane in the region of the front Edge 15 of the work surface 4 provided suction opening 16 meets in its zone 27 adjacent to the work surface 4. The suction opening 16 extends over the entire width of the working opening 6. The section 24 of the front wall 7 is followed upwards by the section 28 in which the front wall rises obliquely inwards. The upper end 29 of section 28 of the front wall lies approximately above the lower edge 30 of section 24, in which the front wall rises outward.

The angle α, at which the section 24 extends to the vertical, is advantageously chosen to be 15 ° to 35 ° and in the preferred case shown is approximately 25 °.

The angle β, at which the section 28 extends to the vertical, is advantageously chosen to be 5 ° to 15 ° and in the preferred case shown is approximately 8 °.

The suction opening 18 provided on the rear edge 17 of the work surface 4 is provided above the work surface 4 on the lower edge 31 of the rear wall 19 of the work space 2 or of the box 3; the lower edge 31 lies above the level of the work surface 4. The height of the suction opening 18 can be changed with a limiting body 37 arranged on the rear wall 19 so as to be height-adjustable, the air flow passing through the suction opening 18 being adjustable in this way.

A flow-guiding wall 34 running obliquely downwards into the work area 2 at the top of the suction opening 18 from the rear wall 19 of the work area 2 or box 3 contributes to the uniformity of the air flow flowing through the work area 2 due to its mirror image directed towards the section 24 of the front wall 7 . The flow control wall 34 merges via a rounding 35 into a boundary wall 36 which forms the upper side of the suction opening 18 and runs approximately parallel to the work surface 4. In the illustrated case, the flow directing wall 34, the rounding 35 and the boundary wall 36 are combined to form a limiting body 37 which is arranged on the rear wall 19 so as to be adjustable in height.

The wedge-like sections 24 and 28 of the front wall 7 adjoining the working opening 6 are formed by an angled transparent plate, through which the working space 2 can be clearly seen from the outside. The front wall 7 is guided up and down and can, as shown in Figure 3, be raised so far that the lower edge 30 comes to rest on the filter 14, so that the entire working space 2 is freely accessible and, if desired, the filter 14 can be easily replaced from the front.

The front wall 7 can also be moved downward beyond the operating position shown in FIGS. 1 and 2, for which the flow conditions in the work space are designed with particular attention to the air inflow through the work opening 6, until the work opening 6 is closed.

At the upper end of section 28 of front wall 7 there is a bulge 38, which forms a handle for pushing up front wall 7. A light source in the form of a fluorescent tube 39, which serves to illuminate the work space 2, is accommodated in the space created by the bulge 38. The bulge also takes various operating devices 40, such as Control instruments and setting devices for operationally important parameters.

In the embodiment of a safety workbench according to the invention shown in FIGS. 1 to 4, the front suction opening 16 is provided at the level of the work surface 4 and the suction opening 18 is placed above the level of the work surface 4 and the work surface 4 itself is designed to be continuously closed . However, different variants are possible with regard to the arrangement of the suction openings, in particular with regard to the arrangement of the rear suction opening and also with regard to the design of the work surface. Thus, the work surface can not only be designed in the form of a closed plate, which generally brings advantages when setting up the work tools, but can also be provided continuously or in zones with suction openings 32, which can be arranged, for example, in the manner of a grid. This is also the case, for example, in the embodiment shown in FIG. Furthermore, in the embodiment shown in FIG. 5, the rear suction opening 18 is arranged at the level of the work surface 4 and opens into the air duct 10 running underneath the work surface 4. The front suction opening 16 is analogous to the embodiment according to FIGS. 1 to 4 educated. The In both embodiments, the front suction opening 16 and the rear suction opening 18 are covered with suitable grilles 33 for mechanical reasons.

Claims

Claims:

1. Safety workbench with a box (3) enclosing the work space (2) of the workbench (1), the bottom of which forms the work surface (4), which allows access to the work surface on its front side (5) in front of the work surface ¬ clearing work opening (6) and above the work opening has a front wall (7) with a viewing window (8), and with an air filter and ventilation device, which creates a turbulence-free air flow from above towards the work surface ( 9), which is suctioned off in the area of the work surface, suction openings (16, 18) being provided at least in the area of the front edge (15) and in the area of the rear edge (17) of the work area (4), and through which in the area the suction opening (16) provided on the front edge of the work surface is sucked downward during operation, the safety workbench (1) being operated with the air suction from the area d he work surface (4) is accompanied by an air inflow through the work opening, which prevents undesired leakage of substances originating from the work area through the work opening, characterized in that the front wall (7) of the box (3) adjoining the work opening (6) upwards both with its inside (21) and with its outside (22) from the upper edge (23) of the working opening (6) initially rising upwards (24), in the operating position of the front wall leaving the working opening free (7) the plane (26) corresponding to the outside wall surface that rises to the outside onto a suction opening (16) provided in the region of the front edge (15) of the work surface (4) and extending over the entire width of the work surface in the work surface (4) adjacent zone (27), and on the section (24) of the front wall (7 ) towards the top is followed by a section (28) of the front wall (7) that rises inwards.

2. Safety workbench according to claim 1, characterized in that the upper end (29) of the obliquely inwardly rising portion (28) of the front wall (7), seen in plan, approximately above the lower edge (30) of the obliquely outward directed section (24) of the front wall (7).

3. Safety workbench according to claim 1 or 2, characterized gekenn¬ characterized in that the obliquely outwardly rising portion (24) of the front wall (7) extends at an angle of 15 ° to 35 ° to the vertical.

4. Safety workbench according to claim 3, characterized in that the inclined portion (24) of the front wall (7) extends at an angle of approximately 25 ° to the vertical.

5. Safety workbench according to one of claims 1 to 4, characterized in that the obliquely inwardly rising portion (28) of the front wall (7) extends at an angle of 5 ° to 15 ° to the vertical.

6. Safety workbench according to claim 5, characterized in that the obliquely inwardly rising portion (28) of the front wall (7) extends at an angle of about 8 ° to the vertical.

7. Safety workbench according to one of claims 1 to 6, characterized in that a suction opening (18) provided on the rear edge (17) of the work surface (4) above the work surface (4) on the lower edge (31) of the rear wall (19) of the Work area (2), which edge (31) is at a distance above the level of the work surface (4) is provided.

8. Safety workbench according to claim 7, characterized in that the height of the suction opening (18) provided on the rear edge (17) of the working surface (4) can be changed with a limiting body (37) which is arranged in a height-adjustable manner on the rear wall (19).

9. Safety workbench according to claim 7 or 8, characterized gekenn¬ characterized in that provided on the top of the rear edge (17) of the work surface (4) provided suction opening (18) from the rear wall (19) of the work space (2) obliquely after flow-guiding wall (34) running down into the working space (2) is provided.

10. Safety workbench according to claim 9, characterized in that the wedge-like flow guide wall (34) below via a rounding (35) in a the top of the rear edge (17) of the work surface () provided suction opening (18) forming approximately parallel to Work surface trending Boundary wall (36) merges.

11. Safety workbench according to claims 8 and 10, characterized in that the flow guide wall (34), the rounding (35) and the boundary wall (36) are combined to form a boundary body (37).

12. Safety workbench according to one of claims 1 to 11, characterized in that the adjoining the working opening (6) upwards and obliquely inwardly extending sections (24, 28) of the front wall (7) by an angled transparent Plate are formed.

13. Safety workbench according to one of claims 1 to 12, characterized by the fact that the front wall (7) is displaceably guided up and down and can be moved downwards until the work opening (6) is closed.