Laboratory fume hood with profiled frame in the front slide
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-05-15
- Publication Date
- 2026-04-08
AI Technical Summary
Current laboratory fume hoods face challenges in enhancing safety and retention capacity while reducing energy requirements, particularly in the design of cross slides and air flow management.
The implementation of a laboratory fume cupboard with a frame profile on the front slide that features airfoil-shaped inflow surfaces on its frame elements and side posts, which guide room air into the fume hood interior, reducing turbulence and pollutant release, and optimizing the flow to minimize energy consumption.
This design enhances safety by containing pollutants within the fume hood and reduces energy consumption by ensuring efficient air flow, minimizing premature separation and backflow, thus maintaining a healthier work environment and lowering operational costs.
Smart Images
Figure EP2024063324_05122024_PF_FP_ABST
Abstract
Description
[0001] LABORATORY FUME HOOD WITH FRAME PROFILE IN THE FRONT SLIDE
[0002] The present invention relates to a frame profile for the sash of a laboratory fume hood.
[0003] Such devices, such as fume hoods, are an essential component of laboratories. All laboratory work that involves handling gases, vapors, suspended particles, or liquids in dangerous quantities and concentrations must be carried out in fume hoods to protect laboratory personnel. Furthermore, fume hoods are also intended to protect laboratory personnel from fire and, if necessary, explosions occurring within the workspace. For this purpose, the workspace is designed to be closed at the rear and on both sides. Only on the user side, i.e. the front, is a vertically movable sash provided. This sash can also have one or more manually movable horizontal cross slides, which allow access to the workspace even when the sash is vertically closed.DE 10 2016 113 822 A1 concerns a ventilated safety cabinet with a housing and a horizontally sliding drawer. The drawer is automatically retracted by means of a motor and a toothed belt.
[0004] DE 20 2006 007 633 U1 also discloses a safety cabinet for storing explosive substances. The safety cabinet has a cabinet door that can be opened and closed pneumatically.
[0005] DE 10 2012 011 775 A describes a control device for a laboratory fume hood, in particular a position sensor which detects the position of the front sash of the laboratory fume hood.
[0006] DE 10 2008 030 029 B4 discloses a fume hood comprising a sash with two transverse sashes. An airfoil is arranged on the underside of the sash. Airfoils are also arranged on the side posts of the fume hood.
[0007] DE 103 38 284 B4 also discloses a laboratory fume hood which has respective flow profiles on the underside of the sash and on the front of the side posts.
[0008] An object of the present invention is to further increase the safety and thus the retention capacity of a laboratory fume cupboard having at least one cross slide and to further reduce the energy consumption of such a laboratory fume cupboard.
[0009] This object is solved by the subject matter of independent claim 1. Optional or preferred features of the invention are specified in the dependent claims.
[0010] According to the invention, a laboratory fume hood is provided which has two side posts and a front sash which is connected to the side posts so as to be movable in the vertical direction for opening and closing a fume hood interior, wherein the front sash comprises a frame in which at least one cross slide which is movable in the horizontal direction is arranged and which, in an open position, defines a cross slide access opening into the fume hood interior, and wherein the frame has an inflow surface for room air which is at least partially convex and faces the cross slide access opening.
[0011] Preferably, the entire frame flow surface is convex and faces the cross slide access opening.
[0012] Even more preferably, the frame flow surface is designed in the shape of an airfoil.
[0013] It is advantageous if the frame has an upper horizontally extending frame element and a lower horizontally extending frame element which extend from one side post to the other side post, and if the inflow surfaces of the upper horizontally extending frame element and the lower horizontally extending frame element are designed in the shape of an airfoil.
[0014] It is also advantageous if the frame has a first vertically extending frame element and a second vertically extending frame element, and if the inflow surfaces of the first vertically extending frame element and the second vertically extending frame element are designed in the shape of an airfoil.
[0015] Preferably, the upper horizontally extending frame element is mitred to the first vertically extending frame element and to the second vertically extending frame element.
[0016] It is also preferred if the lower horizontally extending frame element is connected to the first vertically extending frame element and to the second vertically extending frame element at a miter.
[0017] According to a preferred embodiment of the invention, a vertical edge of the cross slide has a cross slide inflow surface for room air, which is convex.
[0018] Even more preferably, the convex cross slide inflow surface is provided on a cross slide attachment element which is attached to the vertical edge of the cross slide.
[0019] Furthermore, a horizontal cross-sectional area of the convex
[0020] The cross-slide inflow surface is crescent-shaped. It is advantageous if a horizontal cross-sectional area of the convex cross-slide inflow surface has an elliptical shape, in particular enclosing a circular arc in a range of 60° to 120°.
[0021] It is even more advantageous if a front end of each side post is designed with a convex side post inflow surface for room air.
[0022] It is also preferred if a vertical hollow profile is arranged on the front end face of each side post, which has the convex side post inflow surface.
[0023] According to a further preferred embodiment of the invention, a front edge of the worktop, which delimits the working interior on the floor side, is formed with a convex worktop flow surface for room air.
[0024] According to yet another preferred embodiment of the invention, a horizontal hollow profile is arranged on the front edge of the worktop, which has the convex worktop flow surface.
[0025] The invention will now be described purely by way of example using a preferred embodiment and with reference to the accompanying figures. The figures show:
[0026] Fig. 1 is a perspective view of a conventional laboratory train;
[0027] Fig. 2 is a front view of a front sash of a conventional laboratory train having three cross sashes;
[0028] Fig. 3 is a perspective view of a laboratory train according to a preferred embodiment of the invention;
[0029] Fig. 4 is a vertical sectional view of a portion of the fume hood shown in Fig. 3;
[0030] Fig. 5 is a front view of the fume hood shown in Fig. 3, partially sectioned horizontally;
[0031] Fig. 6A shows the flow behavior of incoming room air through a conventional sash profile; and Fig. 6B shows the flow behavior of incoming room air through a sash profile according to the invention.
[0032] The fume hood 1 shown in perspective in Fig. 1 corresponds approximately to the fume hood that has been marketed by the applicant almost worldwide under the name Secuflow® since around 2002. This fume hood is equipped with a support jet technology developed by the applicant and, due to the support jet technology, requires an exhaust air volume flow of only 270 m 3 / (h linear meter).
[0033] The laboratory fume hood 1 has a fume hood interior 30 which is delimited at the rear by a rear wall, preferably by a baffle wall 32 spaced from the rear wall, laterally by two side walls 36, at the bottom by a floor plate 34 or worktop, at the front by a lockable sash 70 and at the ceiling preferably by a ceiling panel.
[0034] The sash 70 is preferably constructed in several parts such that several vertically movable window elements extend telescopically one behind the other in the same direction when the sash 70 is opened and closed. The window element located furthest down in the closed position of the sash 70 preferably has an aerodynamically optimized profile on its front edge, for example, an airfoil profile 75. In addition, the sash 70 has horizontally movable window elements, so-called cross slides 71, which allow laboratory personnel access to the fume cupboard interior 30 even when the sash 70 is closed. The cross slides 71 are enclosed by frame elements, of which only the vertical frame elements 72 are shown in Fig. 1.
[0035] At this point, it should be noted that the sash 70 can also be designed as a two-part sliding window, the two parts of which can be moved in opposite directions vertically. In this case, the opposing parts are coupled via cables or belts and pulleys to weights that balance the mass of the sash 70.
[0036] Preferably, a duct is located between the baffle wall 32 and the rear wall of the fume hood housing 60, which leads to an exhaust air collection duct 50 on the top side of the fume hood 1. The exhaust air collection duct 50 is connected to an exhaust air system installed in the building. A cabinet 62 is arranged below the worktop 34 of the fume hood interior 30, which serves as storage space for various laboratory equipment. This cabinet 62 is to be understood, in the sense of the terminology used here, as part of the housing 60 of the fume hood 1.
[0037] Hollow profiles 10 are provided on the front end faces of the side posts 61 of the fume hood 1. A hollow profile 20 is also provided on the front end face or on the front edge of the worktop 34.
[0038] When we refer to "at the front end" or "leading edge," this term is not to be understood literally. Rather, it also refers to structures that are intended or attached only in the area of the front end or leading edge.
[0039] Similar to the aerodynamically optimized airfoil profile 75 on the underside of the lowest sash element 70, the airfoil-shaped inflow side of the hollow profile 10 or the side post profile 10 is also preferably aerodynamically optimized. The same preferably applies to the hollow profile 20 on the front face of the worktop 34. The airfoil-like or flow-optimized profile geometry enables a low-turbulence, and in the best case, even a turbulence-free, inflow of room air into the fume cupboard interior 30 when the sash 70 is partially or fully open.
[0040] The reason for this is that the wing-like profile geometry of the profiles 10, 20, 75 is designed in such a way that a flow separation of the incoming room air only takes place at the downstream edge (area) of the profile geometry, and thus only within the extractor interior space 30 (see also Fig. 6B).
[0041] With the help of the hollow profiles 10, 20, so-called support jets, i.e. compressed air jets consisting of compressed air, are introduced along the side walls 36 and the worktop 34 into the fume cupboard interior 30. These compressed air jets are conventionally generated by a fan arranged below the worktop 34 and within the housing 60. The hollow profiles 10, 20 are preferably located in front of the plane of the foremost sash element 70. The compressed air jets therefore preferably only reach the fume cupboard interior 30 when the sash 70 is partially or fully open. The fume cupboard 1 shown in Fig. 1 is to be seen purely as an example, since the invention can be applied not only to a fume cupboard 1 as shown in Fig. 1, but is also applicable to other types of fume cupboards, for example tabletop fume cupboards, low-ceiling tabletop fume cupboards, deep fume cupboards, walk-in fume cupboards and mobile fume cupboards.These fume hoods also comply with the European standard series DIN EN 14175, which is valid on the filing date of this patent application. Furthermore, the fume hoods can also comply with other standards, such as ASHRAE 110 / 2016, which is valid for the USA.
[0042] Any reference to a standard in this description and the patent claims always refers to the currently valid standard. This is because experience shows that the requirements specified in standards are becoming increasingly strict, and thus a fume hood that meets the current standard also meets the requirements of an older standard.
[0043] Fig. 2 shows a front view of an exemplary sash 70 known from the prior art, which has three cross slides 71. Each cross slide 71 has a recessed grip 71a, by means of which the respective cross slide 71 can be manually moved horizontally if necessary. The cross slides 71 are not all located in a vertical plane, but are slightly offset horizontally from one another, since each cross slide 71 is guided in a dedicated guide in the horizontal frame elements 73, 74.
[0044] Likewise, Fig. 2 shows the vertical frame elements 72, in each of which a vertical edge 76 of the left and right cross slide 71 shown in Fig. 2 is received in the closed position. The frame elements 72, 73, 74 enclose the cross slide 71 like a closed picture frame encloses a picture. Furthermore, the frame elements 72, 73, 74 are conventionally planar, i.e. the inflow surface for room air during operation of the laboratory fume hood 1 is flat. Furthermore, the aerodynamically optimized airfoil 75 already mentioned in connection with Fig. 1 can be seen on the lower edge of the front sash 70, i.e. on the lower edge of the frame element 73. Fig. 3 shows a perspective view of a laboratory fume hood 1 according to a preferred embodiment of the invention. In contrast to the fume cupboard 1 shown in Fig. 1, the fume cupboard 1 in Fig. 3 is shown without the base unit 62.Furthermore, the sash 70 comprises frame elements 82, 83, 84, comparable to a picture enclosed by a closed frame. Thus, the sash 70 comprises two vertical frame elements 82, which are spaced apart by the width of the sash 70, and a lower horizontal frame element 83 and an upper horizontal frame element 84, which are spaced apart by the height of the sash 70 or the cross slide 71, as the case may be. In Fig. 3, the left cross slide 71 is shown in a slightly open position, in which the cross slide 71 defines a cross slide access opening 71a, through which the fume cupboard interior 30 is accessible even when the sash 70 is closed. The vertical edge 76 of the cross slide 71, which is not visible in Fig. 3, is preferably provided with a plug-on element 85, since it extends over the entire height of the vertical edge 76 of the cross slide 71.
[0045] Fig. 4 is a vertical sectional view of a portion of the fume hood 1 shown in Fig. 3. Fig. 4 shows the worktop 34, at the front edge of which a hollow profile 20 is provided, which has an aerodynamically optimized, airfoil-shaped inflow surface 20a for room air. A duct 21 is also indicated, from which compressed air (so-called support jets) exits into the fume hood interior 30.
[0046] The front sash 70 comprises two cross sashes 71 that can be moved in opposite directions in the horizontal direction, to the underside of which the lower horizontal frame element 83 is attached. The lower horizontal frame element 83, which is arranged in direct proximity to the hollow profile 20, has a convex inflow surface 83a for the room air. The inflow surface 83a is preferably aerodynamically optimized and has a wing-shaped design.
[0047] An inflow surface 83a, as described in connection with the lower horizontal frame element 83, is also provided on the other frame elements 82 and 84. This can be partially seen in Fig. 5, which is a partially vertically sectioned front view of the fume hood shown in Fig. 3. In Fig. 5, the two vertical frame elements 82 are shown partially horizontally sectioned, and it can be seen that both vertical frame elements 82 each have a convex, preferably aerodynamically optimized, airfoil-shaped inflow surface 82a for room air. It can also be seen that the hollow profiles 10, which are provided in the region of the end faces of the side posts 61 and in the immediate vicinity of the vertical frame elements 82, each have a convex inflow surface 10a, which is preferably airfoil-shaped.
[0048] Although it is not clearly visible in Fig. 5, the upper horizontal frame element 84 is also formed with a convex, preferably aerodynamically optimized, wing-shaped inflow surface 84a for room air.
[0049] Fig. 5 shows a front sash 70 with two cross slides 71 arranged in the frame elements 83 and 84 for counter-rotating horizontal movement. The vertical edges 76 of the two cross slides 71 also have a convex cross slide edge inflow surface 85a. The convex inflow surface 85a is preferably provided on a cross slide attachment element 85, which is attached to the vertical edge 76. A horizontal cross-sectional area of the inflow surface 85a of the cross slide attachment element 85 is preferably crescent-shaped. More preferably, the horizontal cross-sectional area of the inflow surface 85a has an elliptical shape; in particular, the horizontal cross-sectional area of the inflow surface 85a encloses a circular arc in a range of 60° to 120°.
[0050] As indicated in Fig. 5, the frame members 82, 83, 84 are mitered and butt-jointed. In other words, the upper horizontal frame member 84 is mitered to both vertical frame members 82, and the lower horizontal frame member 83 is mitered to both vertical frame members 82.
[0051] In the case of the inflow surface 83a, the convexity follows the room air flow direction from bottom to top, i.e., the convex inflow surface 83a forces the room air to move upwards, while the convex inflow surface 84a forces the room air to move downwards. In the case of the inflow surfaces 82a, however, the convexity is such that the room air undergoes a sideways deflection movement, such that it must overcome a sideways rising hill before entering the extractor interior 30.
[0052] Similar considerations apply to the inflow surface 85a of the cross-slide attachment element 85, which is attached to the vertical edge 76 of the cross-slide 71. However, with the difference that in the area of the vertical edge 76, viewed in the direction of room air flow, the inflow surface 85 does not rise any further, but rather runs downwards from there. In other words, the plane of symmetry of the inflow surface 85a of the cross-slide attachment element 85 preferably lies in the plane of the cross-slide 71.
[0053] The shape of the underside of the lower frame element 83 corresponds almost exactly to the shape of the top side of the hollow profile 20. In other words, the shape of the underside of the lower frame element 83 is complementary to the shape of the top side of the hollow profile 20. The same applies to the vertical frame elements 82 and the hollow profiles 10.
[0054] Fig. 6A illustrates the flow behavior of incoming room air through a conventional sash profile 73. The flow pattern, which is only schematically indicated, clearly shows the early flow separation already at the front edge of the sash profile 73. The flow separation thus occurs outside the fume hood interior 30 of the laboratory fume hood 1.
[0055] Fig. 6B, on the other hand, shows the flow behavior of incoming room air through a sash profile 83 according to the invention. Here, the flow separation occurs much later, namely at the rear edge of the sash profile 83, and thus within the fume cupboard interior 30 of the laboratory fume cupboard 1. The significantly smaller return flow area in the inventive embodiment of Fig. 6B results in a smaller potential pollutant discharge compared to the significantly larger return flow area of the conventional embodiment of Fig. 6A.
[0056] Thanks to the aerodynamically optimized frame elements 82, 83, 84 of the sash 70, the room air can flow into the fume hood interior 30 during operation of the fume hood 1 through a partially opened cross sash 71 without premature flow separation, which in turn effectively prevents potential contaminants from escaping from the fume hood interior 30 and the associated health hazard for the laboratory employee. This is particularly advantageous if the laboratory employee decides to perform any work within the fume hood interior 30 through the cross sash 71 rather than the sash 30, keeping the sash 30 closed. The inflow surfaces 82a, 83a, 84a, 85a of the frame elements 82, 83, 84 and of the cross slide plug-on element 85, which are at least partially convex, are arranged such that they face the cross slide access opening 71a when the cross slide 71 is open.In addition, the energy consumption of the fume hood 1 can be reduced due to the improved inflow of room air through the cross slide 71, because a reduced exhaust air volume flow is sufficient to ensure the same escape safety.
Claims
Patent claims:
1. Laboratory fume cupboard (1), comprising two side posts (61) and a front sash (70) which is connected to the side posts (61) so as to be movable in the vertical direction and for opening and closing a fume cupboard interior (30), wherein the front sash (70) comprises a frame (82, 83, 84) in which at least one cross sash (71) which is movable in the horizontal direction is arranged and which, in an open position, defines a cross sash access opening (71a) into the fume cupboard interior (30), and wherein the frame (82, 83, 84) has an inflow surface (82a, 83a, 84a) for room air, which is at least partially convex and faces the cross sash access opening (71a).
2. Laboratory fume hood (1) according to claim 1, wherein the entire frame flow surface (82a, 83a, 84a) is convex and faces the cross-slide access opening (71a).
3. Laboratory fume hood (1) according to claim 1 or 2, wherein the frame flow surface (82a, 83a, 84a) is designed in the shape of an airfoil.
4. Laboratory fume hood (1) according to one of the preceding claims, wherein the frame (82, 83, 84) has an upper horizontally extending frame element (84) and a lower horizontally extending frame element (83) which extend from one side post (61) to the other side post (61), and wherein the inflow surfaces (84a, 83a) of the upper horizontally extending frame element (84) and the lower horizontally extending frame element (83) are designed in the shape of an airfoil.
5. Laboratory fume hood (1) according to one of the preceding claims, wherein the frame (82, 83, 84) has a first vertically extending frame element (82) and a second vertically extending frame element (82), and wherein the inflow surfaces (82a) of the first vertically extending frame element (82) and of the second vertically extending frame element (82) are designed in the shape of airfoils.
6. Laboratory fume hood (1) according to claims 4 and 5; wherein the upper horizontally extending frame element (84) is connected to the first vertically extending frame element (82) and to the second vertically extending frame element (82) at a miter.
7. Laboratory fume hood (1) according to one of claims 4 to 6; wherein the lower horizontally extending frame element (83) is connected to the first vertically extending frame element (82) and to the second vertically extending frame element (82) at a miter.
8. Laboratory fume hood (1) according to one of the preceding claims, wherein a vertical edge (76) of the cross slide (71) has a cross slide edge inflow surface (85a) for room air, which is convex.
9. Laboratory fume hood (1) according to claim 8, wherein the convex cross-slide edge inflow surface (85a) is provided on a cross-slide attachment element (85) which is plugged onto the vertical edge (76) of the cross-slide (71).
10. Laboratory fume hood (1) according to claim 8 or 9, wherein a horizontal cross-sectional area of the convex cross-slide edge inflow surface (85a) is sickle-shaped.
11. Laboratory fume hood (1) according to one of claims 8 to 10, wherein a horizontal cross-sectional area of the convex transverse slide edge inflow surface (85a) has an elliptical shape, in particular enclosing a circular arc in a range of 60° to 120°.
12. Laboratory fume hood (1) according to one of the preceding claims, wherein a front end face of each side post (61) is formed with a convex side post inflow surface (10a) for room air.
13. Laboratory fume hood (1) according to claim 12, wherein a vertical hollow profile (10) is arranged on the front end face of each side post (61), which has the convex side post inflow surface (10a).
14. Laboratory fume cupboard (1) according to one of the preceding claims, wherein a front edge of the worktop (34), which delimits the working interior (30) on the floor side, is formed with a convex worktop inflow surface (20a) for room air.
15. Laboratory fume hood (1) according to claim 14, wherein a horizontal hollow profile (20) is arranged on the front edge of the worktop (34), which has the convex worktop flow surface (20a).