DE102012011344A1 - fume hood - Google Patents

Abstract

The invention relates to a fume hood (2) which has side walls (8, 10), a front part (14) and a rear wall (6) which surround a working space (3) as structural parts, and an optical monitoring device (22) for detecting Obstacles, the front part (14) having an access opening (18) via which the working space (3) is accessible in an access direction, and wherein an opening size of the access opening (18) is adjustable by a sliding element (14) received in the front part (14). 20) is changeable. According to the invention, the optical monitoring device (22) is provided in a structurally fixed manner on at least one structural part (6, 8, 10, 14) for monitoring precisely one planar space area (50) which is located behind the sliding element in the working space (3) in the access direction (20) is arranged. For this purpose, the monitoring device is preferably arranged on the front part itself directly behind the access opening and forms a light curtain parallel to the sliding element, or is designed as a camera.

Description

The invention relates to a fume hood with the features of the preamble of claim 1.

Such fume hoods generally have a work space surrounded by a floor, side walls, a rear wall, a ceiling and a front part and accessible via an access opening formed in the front part.

At such fume hoods high security requirements are made. In particular, when working with hazardous pollutants, a possible emission of pollutants from the access opening must be reliably prevented.

Therefore fume hoods are often provided in the rear, opposite their front portion and / or an upper area with air extraction. The access opening can be completely or partially closed with a sliding element or sliding window.

However, obstacles in the area of the travel path of the sliding element can impair the proper operation of the fume hoods or the fume hood or z. B. by falling containers endanger the user.

The EP 0 714 711 B1 proposes for this purpose the monitoring of the closing plane of the sliding element by a photoelectric scanning device, which is attached to the lower edge of the movable sliding element and by a light beam emitting a first element and a light beam receiving second element is formed.

Such a design on the underside of the sliding element allows detection of the closing plane formed by the sliding element; However, the effort of contacting of attached to the movable sliding element electronic devices is significant.

Furthermore, photocells are known for other purposes. The US-A 4,774,878 and US-A-6 024 638 show extraction devices, each having a photocell on the housing structure of the trigger, namely a forwardly projecting portion of the side wall, is provided for monitoring an outside space in front of the access opening. For this purpose, the side walls in the area in front of the access opening and the sliding element extend obliquely away from the page, so that the photocell detects the outside space in front of the access opening. The sliding element can therefore be automatically closed when the operator moves away from the outside of the fume hood.

Monitoring of an outdoor space in front of the fume hood by means of such a photocell or a "photoelectric eye" is a sensible measure to check the presence of operating personnel and to automatically close an open, unguarded room. However, they are not suitable as anti-trap because they detect the front area in front of the sliding element and furthermore can not safely distinguish between impermissible objects and other permissible objects in their detection area, in particular structural parts such as the side walls.

The object of the present invention is to provide a fume hood, which enables safe operation.

This object is achieved by a fume hood according to claim 1. The dependent claims describe preferred developments.

According to the invention, an optical monitoring device is thus arranged in a structurally fixed manner on at least one structural part, that is to say that H. not movably arranged or fixed to the at least one structural part. In this case, the optical monitoring device serves to monitor a planar space area which runs behind the sliding element in the working space. The space area to be monitored preferably runs parallel to the sliding element. Advantageously, only this area-area area is monitored and not additional areas of the work space.

Unlike in the EP 0 714 711 B1 is the optical monitoring device thus completely stationary, ie provided on structural parts of the fume hood and not on the movable sliding element. This results, inter alia, simplifications in the contacting. Furthermore, not according to the invention as in the in EP 0 714 711 B1 the closing level, but one level behind the closing level monitors.

Unlike in the US-A-4,774,878 the optical monitoring device does not detect the front space in front of the fume hood in order to check the presence of an operator and close the sliding element in the absence, but the work space itself to disturbing obstacles that may be trapped or destroyed by the sliding element.

According to a particularly preferred embodiment, the space area to be monitored extends from the floor of the working space to the (in particular in the Standard EN 14175 defined) working opening height of currently 50 cm; in the lateral direction, the space-area area advantageously extends to the side Limit, ie either the side walls or - in a training in the rear region of the front part - lateral edge regions of the stationary front part.

Outside the workspace provided detectors such. B. an optical presence sensor, z. B. based on infrared, may optionally be provided in addition; In turn, they then serve to check the presence of the laboratory personnel and, if necessary, independently initiate a closing operation of the sliding element, which in turn can be stopped automatically in the event of the detection of an obstacle in the monitored space area.

According to the invention it is recognized that an attachment to the movable sliding element can be avoided by a flat space surface area is formed directly behind the sliding element, which preferably completely covers the access opening. Thus, objects from the working space can not protrude into the closing plane of the sliding element, since in this case they would have to penetrate or traverse the area-area area to be monitored. Such monitoring directly behind the sliding element can, for. B. can be achieved by attaching the optical monitoring device on the front part.

Opposite a z. B. on the sash mounted light barrier as in the EP 0 714 711 B1 is advantageous in this invention that a closing process when detecting an obstacle does not need to be initiated. A warning message can also be issued if the sash is still open.

The optical monitoring device supplies a measuring signal to a control device, which can serve in particular for interrupting a closing operation of the motor-driven closing element. The control device can serve to control a motor drive device of the sliding element and automatically interrupt the closing process when a corresponding measurement signal indicative of an obstacle is picked up. Alternatively, the control device can also output a stop signal to a further control device provided for controlling the drive device.

By according to the invention, only the planar area-area area and not further areas in the working space are monitored, it can be prevented that objects in the working space are erroneously recognized as disturbing or obstacle, even though they do not constitute an obstacle during the closing process.

In particular, the optical monitoring device can form a light curtain or a plurality of parallel light beams in the area-area area to be monitored; Here, only in one direction extending parallel light rays or a light grid can be formed from intersecting, parallel light beams. The light curtain or the light beams are thus limited to the space area to be monitored so as not to erroneously recognize other objects as obstacles.

To form such a light curtain, the optical monitoring device accordingly has a plurality of optical transmitters and optical receivers; the optical transmitters may in particular be laser diodes; the optical receivers are correspondingly photosensitive elements, such. As photodiodes or phototransistors, which are set according to the wavelength of the light curtain.

By having these optical transmitters and receivers in the limiting lateral structure, i. H. the side walls or a lateral edge region of the front part, it can be ensured that actually the entire space-area area through which an obstacle could protrude forward in the closing plane of the closing element, is optically detected.

In the embodiment with parallel light beams or light grids, the individual measurement signals of the optical receiver, in particular in an AND circuit can be logically linked, d. H. it is detected an obstacle, even if only a single receiver detects an interruption of the light beam. Thus, the data communication between the monitoring device and the higher-level control device can be stopped; The AND operation can already be performed in the monitoring device itself so that only one error signal is transmitted to the control device instead of the multiple receiver signals.

The monitoring device may, according to an alternative embodiment, be formed with an optical camera which detects optical markings; the optical markings are in this case in an area bounding the planar space area area, z. B. on the side walls or an edge or edge of the front part, provided or formed. The optical marks can z. B. specific color markers, and / or have specific symbols. In such an embodiment, an image evaluation method is provided directly in the monitoring device or the higher-level control device in order to check whether all the optical markings are detected. In this embodiment Thus, compared to the above-mentioned embodiment, the plurality of transmitters and receivers are omitted; The optical markers can be made relatively simple or inexpensive, but the camera and the subsequent image analysis is somewhat more expensive.

If necessary, the camera can also detect a larger spatial area in such an embodiment; only relevant is that it detects all optical markers and their output to the control device measurement signal depends only on the detection of the optical markers, and not by the detection z. B. other objects outside the monitored area area.

The invention will be explained in more detail with reference to the accompanying drawings, in which embodiments are shown schematically. Show it:

1 the construction of a fume hood according to an embodiment in a highly schematic representation;

2 a sectional side view of the fume hood, including detail magnification;

3 another embodiment with a camera system.

1 shows you on a rack 1 arranged fume hood 2 with a workroom 3 , the floor formed as a tabletop 4 , a back wall 6 , two side walls 8th . 10 , A blanket 12 and a front part 14 having. The front part 14 is with an access opening 18 provided over which the work space 3 is accessible and their opening size by a in the front part 14 vertically displaceable sliding element 20 changeable or adjustable. On the ceiling 12 or on the back wall 6 is preferably a suction port 44 provided to continuously air from the work space 3 suck.

The front part 14 is by a motor drive device 54 adjustable, wherein the drive device 54 is provided outside the working space and a power transmission z. B. by a - here only hinted - rope, timing belt or chain hoist 55 can be done.

An optical monitoring device 22 is provided in the work space to a space-area area 50 to capture, which is preferably flat and parallel to the sliding element 20 runs.

Down is the monitored space area 50 according to the embodiment of the 2 through a paragraph 14a of the front part 14 limited. Alternatively, there is a boundary through the floor 4 possible. The embodiment shown, however, allows for on the ground 4 objects are not in the space surface area 50 protrude and thus are not recognized as disturbing.

The monitored room surface area points upwards 50 preferably a height of 50 cm, that of the variable working opening height of the free access opening 18 with raised sliding element 20 equivalent. Loud EN 14175 Here is a distinction between the variable working opening height, which is meant here and unconsciously can not be exceeded, and the largest sash opening, which may be after z. B. release a lock can be achieved below.

To the sides is the supervised space area 50 through the side walls 8th and 10 or again by paragraphs on the front part 14 limited.

A control device 52 is z. B. outside the work space 3 provided and outputs first control signals S1 to the motor drive device 54 out. By the control device 52 is an automatic adjustment possible, in which the control device 52 by first control signals S1, the sliding element 20 completely closes.

The optical monitoring device 22 gives measurement signals S2 to the control device 52 indicating the presence or absence of an obstacle in the space area 50 Show.

Upon detection of an obstacle in the space area 50 this is thus the control device 52 communicated, which then by the first control signals S1 or by a specially provided stop signal, the motor drive device 54 stops.

According to the preferred first embodiment of 1 and 2 forms the optical monitoring device 22 in the space-area area 50 a light curtain 30 out.

The light curtain 30 has several rays of light 32 generating optical transmitter 34 , z. B. laser diodes, as well as several the transmitters 34 assigned optical receiver 36 (Sensors) on.

The rays of light 32 can according to 1 run parallel, ie form a line grid, or as a light grid parallel and orthogonal run, ie there are first optical transmitter 34 to Formation of first parallel light beams and second optical transmitter 34 for forming second parallel light beams orthogonal to the first parallel light beams.

The wavelength of the light beams may be in particular in the infrared light range, or even in the visible range.

3 shows a further embodiment in which the optical monitoring device by a camera 42 and optical marks 43 is formed. The camera 42 may possibly also capture a larger solid angle; relevant is that they have all the optical markings 43 detected. Image signals S4 of the camera are subsequently in control device 52 then evaluated whether all optical markings are detected. The optical marks 43 can z. B. be shown as different colors, eg. B. as a changing color line, so that when an obstacle occurs in the monitored area area area according to one or more markers are no longer detected. Furthermore, the optical markers can also have specific patterns that are one-to-one, ie different from one another, so that in each case it is possible to check whether all the optical markings 43 are recorded.

If an obstacle has been detected, in all embodiments, the corresponding signal of the sensors or the camera 42 be used to the closing of the sliding element 20 to interrupt and / or issue a warning message.

According to the invention, when an obstacle is detected, the initiation of the closing process can also be prevented in advance, so that the closing process does not even begin in the first place.

LIST OF REFERENCE NUMBERS

1

frame

2

fume hood

3

working space

4

ground

6

rear wall

8, 10

side walls

12

blanket

14

front part

14a

paragraph

18

access opening

20

sliding element

22

optical monitoring device

30

light curtain

32

light rays

34

optical transmitters, z. B. laser diodes

36

optical receivers or sensors

42

camera

43

optical marks

44

suction

50

to be monitored area area

52

control device

54

motor drive device

55

chain

S1

Control signals to the motor drive device 54

S2

Measuring signals of the optical monitoring device 22

S3

Image signals from the camera 42

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0714711 B1 [0006, 0013, 0013, 0018]
• US 4774878 A [0008, 0014]
• US 6024638 A [0008]

Cited non-patent literature

• Standard EN 14175 [0015]
• EN 14175 [0035]

Claims (15)

Fume cupboard ( 2 ), which has side walls ( 8th . 10 ), a front part ( 14 ) and a back wall ( 6 ), which as structural parts a work space ( 3 ), and an optical monitoring device ( 22 ) for detecting obstacles, wherein the front part ( 14 ) an access opening ( 18 ), over which the working space ( 3 ) is accessible in an access direction, and wherein an opening size of the access opening ( 18 ) by an adjustable in or on the front part ( 14 ) received sliding element ( 20 ) is variable, characterized in that the optical monitoring device ( 22 ) structurally fixed to at least one structural part ( 6 . 8th . 10 . 14 ) for monitoring a space area ( 50 ) provided in the work space ( 3 ) in the access direction behind the sliding element ( 20 ) is arranged. Fume hood according to claim 1, characterized in that the optical monitoring device ( 22 ) for monitoring exactly the area of space ( 50 ) is provided without detection of other areas of space. Fume hood according to claim 1 or 2, characterized in that the optical monitoring device ( 22 ) on the front part ( 14 ) is attached. Fume hood according to one of the preceding claims, characterized in that the space area to be monitored ( 50 ) is flat and parallel to the sliding element ( 20 ) runs. Fume hood according to one of the preceding claims, characterized in that the sliding element ( 20 ) is vertically adjustable and the space area to be monitored ( 50 ) up to the height of the access opening ( 18 ) when the sliding element is raised ( 20 ). Fume hood according to claim 5, characterized in that it has a fuse for the vertical adjustment of the sliding element ( 20 ) to a maximum work opening height and after release of the fuse, the sliding element is further adjustable upwards over the working opening height, wherein the space area to be monitored ( 50 ) extends upwards only up to the working opening height. Fume hood according to one of the preceding claims, characterized in that the space area ( 50 ) as a light curtain ( 30 ) with several parallel light beams ( 32 ), wherein the optical monitoring device ( 22 ) several optical transmitters ( 34 ) for generating a respective light beam ( 32 ) and several, each one transmitter ( 34 ) associated receiver ( 36 ) having. Fume hood according to claim 7, characterized in that the optical transmitter ( 34 ) and receiver ( 36 ) in the front part ( 14 ) and are arranged opposite each other. Fume hood according to claim 7 or 8, characterized in that it comprises a control device ( 52 ) for controlling the optical monitoring device ( 22 ) and evaluation of measurement signals (S2) of the optical monitoring device ( 22 ), wherein the control device ( 52 ) detects an obstacle if at least one recipient ( 36 ) a lack of light beam of the associated transmitter ( 34 ) detected. Fume hood according to claim 9, characterized in that the control device ( 52 ) Measurement signals (S2) of the receiver (S2) 36 ) are processed in a logical AND operation. Fume hood according to one of claims 1 to 5, characterized in that the monitoring device ( 22 ) a camera ( 42 ) and at the edge of the space area ( 50 ) provided optical markings ( 43 ), wherein the camera ( 42 ) for detecting the optical markings ( 43 ) and for generating an image signal (S3), wherein a control device ( 52 ) by means of image evaluation of the image signal (S3) determines whether at least one optical marking ( 43 ) is not detected and recognizes an obstacle depending on this determination. Fume hood according to claim 11, characterized in that the optical markings ( 43 ) Are color markers and / or different symbols. Fume hood according to one of claims 9 to 12, characterized in that it comprises a motor drive device ( 54 ) for moving the sliding element ( 20 ), wherein the control device ( 52 ) or a further control device as a function of the measuring signals (S2) of the optical monitoring device ( 22 ) a stop signal for stopping the closing operation of the motor drive device ( 54 ) and / or to prevent initiation of the closing operation. Fume hood according to claim 13, characterized in that it further comprises an optical presence detector, for. B. IR sensor, for monitoring an operating area before the fume hood and outputting a presence signal when detecting an operator, wherein the control device ( 52 ) in the absence of the presence signal, outputs the stop signal. Fume hood according to one of claims 9 to 14, characterized in that the control device ( 52 ) emits a warning signal or error signal when an obstacle is detected.

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