Energy-efficient workbench, in particular cleanroom workbench and methods for operating such a workbench

Abstract

Workbench (1), comprising a work chamber (3) surrounded by a housing (2), wherein the work chamber (3) is accessible through a working opening (4), comprising an air supply device (12) through which pre-assembled supply air can flow into the work chamber (3), and an exhaust air device (14) through which exhaust air can be extracted from the work chamber (3), wherein the exhaust air device (14) is designed such that exhaust air can be at least partially discharged from the workbench (1) and at least partially discharged into the work chamber (3) via an air supply element (15), characterized in that the exhaust air device (14) has an exhaust air pipe (16) which includes a branching section (17) at which the exhaust air pipe (16) is divided into two partial pipes (18), wherein at least one control damper (19) is arranged in each of the partial pipes (18) with which the ratio between exhaust air discharged from the workbench (1) and the air entering the work chamber (3) is controlled. The exhaust air recirculated into the work area is controllable.

Description

The invention relates to a workbench according to the preamble of claim 1 and to a method for operating a workbench according to the preamble of claim 11.Workbenches are used for protecting humans and / or products. The workbenches according to the invention, in particular clean room workbenches or even ultra-clean room workbenches, are technically comparable to prints and safety workbenches. Working and production under low-contamination conditions, including contamination-free conditions, in particular clean room conditions, is an important prerequisite in many sectors of industry in order to be able to ensure the quality of a product and also to protect the employees from possible contamination. This is especially important in food production, medical research and treatment, drug production, genetic engineering, microelectronics, semiconductor manufacturing, optics and laser engineering or nanotechnology.A workbench has an air supply device which supplies a working space with prefabricated air supply. Depending on the desired conditions, the prefabricated supply air is, for example, pretempered, filtered, assembled in a defined manner and / or has a defined air humidity. In addition, the workbench has an exhaust air device which draws the exhaust air out of the work space. The interaction of the supply air device and the exhaust air device firstly protects the product from external contaminants, secondly protects the user of the workbench who carries out work in the workspace from the substances in the workspace and contaminants by the latter.For example, CN 105 983 456 A shows a workbench which has an air supply device and an exhaust air device, so that air supply flows into the working space and exhaust air is extracted from the working space.DE 87 07 093 U1 describes a workbench in which the exhaust air is processed and discharged as exhaust air or returned as recirculation air into the workspace.The pre-assembly of the supply air, in particular for setting a defined temperature and a defined air humidity, is associated with high outlay and in particular high energy costs. The energy required for the pre-assembly leads to high continuously occurring operating costs of such workbenches.It is therefore an object of the invention to eliminate the disadvantages of the prior art and to provide a workbench and a method for operating a workbench which have improved energy efficiency.Main features of the invention are set out in the characterizing part of claim 1 and claim 11. Embodiments are the subject matter of claims 2 to 10 and 12 to 14.The invention relates to a workbench having a working space surrounded by a housing, wherein the working space can be engaged through a working opening, having an air supply device with which prefabricated air supply can be introduced into the working space, and having an exhaust air device with which exhaust air can be extracted from the working space, wherein the exhaust air device is designed such that exhaust air can be at least partially discharged from the workbench and can be at least partially introduced into the working space via an air supply element. The exhaust air device has an exhaust air pipe which comprises a branching section at which the exhaust air pipe is separated into two sub-pipes, wherein at least one regulating flap is arranged in each of the sub-pipes, with which regulating flap the ratio between exhaust air led out of the workbench and exhaust air fed back into the workspace can be regulated.This makes it possible to create a workbench which has a significantly improved energy efficiency compared to the known workbenches because the exhaust air, which already has the desired temperature and humidity of the prefabricated supply air, is fed back at least partially via the supply air element into the workspace. As a result, less prefabricated supply air is required, which is flown into the working space by the supply air device, and a part of the energy costs expended for the prefabricated arrangement are saved.The housing of the workbench forms an interior space which represents the working space. The workspace of the workbench represents a protected space in which a user can work, wherein both the user can be protected from contamination by the substances located in the workspace and the substances can be protected from contamination from the outside. When working in the workbench, the user stands in front of the same and accesses the working space through the working opening in order to perform work there.For example, in chemical operations, it is necessary that no chemicals, in particular gases and vapors, can escape to the outside, as a result of which the user could suffer severe health damage. For this purpose, the exhaust air device is provided, which draws the exhaust air from the working space.The exhaust air is at least partially led out of the workbench and at least out of the space in which the workbench is arranged. In particular, the exhaust air is guided out of the building in which the workbench is arranged. Depending on the field of use, cleaning steps can be provided before the exhaust air is released into the environment.In certain applications, it may be necessary to avoid any contamination from the outside, for which reason a prefabricated, defined supply air flows from the supply air device into the working space during operation of the workbench. As a result, no gases and vapors, dust particles or other contaminants can pass from the environment of the workbench into the working space and the object to be processed located there. By object can be understood, for example, substances, analysis samples, medicaments or semiconductor plates.The supply air is prefabricated, i.e. it is preheated to a specific temperature, for example, wherein only temperature fluctuations of 0.5 to 1° C. are permitted depending on the field of application. The supply air is preferably tempered to 20 to 22° C., particularly preferably to 21° C., and thus prefabricated. The pre-assembly can also include, for example, the setting of a defined air humidity. The prefabricated supply air preferably has a relative air humidity of 50%, wherein preferably fluctuations in the value of the relative air humidity by plus / minus 10% are permitted. In addition, as a preliminary assembly, it is preferably provided that the supply air has a specific composition. This allows different operating conditions to be ensured for different fields of application.The supply air flowing into the working space is pumped to exhaust air after flowing through the working space and as such is pumped off from the exhaust air device. The supply air and exhaust air are preferably air, a defined gas composition, a protective gas, for example nitrogen or noble gas, or a mixture thereof. The type of supply air used depends on the field of application in which the workbench is used. For example, applications using oxygen-sensitive substances require a protective gas atmosphere. Working with moisture-sensitive substances is also made possible if the supply air is dried before it flows into the working space.Preferably, the housing forms an essentially cuboidal interior space which represents the working space. Consequently, the housing surrounds the working space. In addition to the preferred embodiment, it is also conceivable to provide housings of a different shape, which correspondingly form non-cuboidal interior spaces and thus working spaces.The housing preferably comprises six surfaces forming the outer boundary of the housing, these six surfaces forming two side surfaces, a rear surface, a front surface, an upper surface and a lower surface. The spatial assignment of the surfaces takes place from the working direction of a user of the workbench.The side surfaces and the rear surface are preferably formed closed. As a result, a working space can be formed which can be engaged only on one side, namely in particular on the front side. This increases the safety of the user and of the object to be processed and minimizes handling errors of the user.The working space can be engaged through a working opening. In other words, a user can access the workspace from the outside and perform work within the workspace. Works performed within the workspace include, for example, chemical experiments, the production of semiconductors, and the production of drugs. The formulation of the one working opening does not exclude the fact that a plurality of openings are also provided, which are combined under the formulation of a working opening, which openings allow engagement and working in the working space.The working opening is preferably designed in such a way that it can be closed. This makes it possible to obtain a working space which can be engaged through the working opening if necessary, but which can also be closed when the workbench is not in use. As a result, the energy efficiency can be further improved because, in a state of non-use of the workbench, the amount of supply air and exhaust air can be significantly reduced, as a result of which less prefabricated supply air and energy required for this must be provided. This can be carried out, for example, by automatic detection of non-use, which can be carried out in particular by means of a light barrier, and automatic regulation of the amount of supply air and exhaust air.The working opening is preferably embodied such that it can be closed by means of a closure element. In a preferred embodiment, the front surface of the housing has a front slide as a closure element, which in particular consists of a displaceable pane. Before use of the workbench and the work space, the front slide can be opened by sliding the same. If the workbench is no longer used, the front slide can be closed by the latter being displaced into a closing position. The working opening is thus closed. This allows simple use of the workbench and at the same time opens up a possibility of further energy reduction.Preferably, the front slide is designed vertically displaceably as part of the housing. This allows simple use of the workbench.In an alternative embodiment, the front surface of the housing has a disk which has working openings. These working openings are in particular formed as recesses which have a round or oval shape. In a preferred development, the recesses are closed with gloves as closure element, whereby the working space can be engaged via these gloves without an uncontrolled open opening to the environment of the working space being present. This also allows the energy efficiency to be increased because less prefabricated supply air is required in relation to partially and / or temporarily open workbenches.In a further alternative embodiment, it is provided that the front surface has a disk which has a working opening which can be closed by means of a second displaceable disk as a closure element.In a preferred embodiment, it is provided that a seal is arranged on the working opening and / or the closure element. This seal seals the working opening in a closed state. Thereby, in a closed state of the working port, a sealed working space is obtained and the energy efficiency is further increased.In a preferred development, the working opening can be closed by means of a front slide as a closure element, which has a seal in a region which faces the working opening. As a result, the working space is sealed off from the outside in a closed state of the front slide. Preferably, work in the working space can also be carried out by glove interventions when the working opening is closed and sealed.In a preferred embodiment, the seal is a pneumatic seal. As a result, a working space which is as tight as possible is obtained.In a preferred embodiment, the entire surface of the housing delimiting the working space is formed free of metal. As a result, the workbench can be used for work under clean room conditions. In a preferred development, the entire surface of the workbench is formed without metal. This makes it possible to use it in clean rooms. Due to the freedom from metal, the corresponding surface is corrosion-free and contamination of the processed objects by metallic traces is prevented. As a result, highly sensitive samples can also be examined and processed.In a preferred development, all surfaces of the system which comprises the workbench and all elements which carry incoming air and outgoing air are of metal-free design. This ensures a maximum level of freedom from contamination.In a preferred embodiment, the metal-free surfaces comprise a plastic. Preferably, the plastic is selected from the group: polypropylene, teflon and perfluoroalkoxy polymer. The plastic can be selected depending on the field of application of the workbench and the required stability and is also simple to process.The supply air device preferably has a supply air filter. As a result, the incoming supply air is freed from particles and other impurities before reaching the working space. If a very fine particle filter is used as the air supply filter, the air supply flowing into the working chamber is essentially free of particles. This makes it possible to prevent contamination of the object to be processed in the working space by particles in the supply air. In addition, for use in clean rooms, a freedom from particles of the supply air is prescribed.Preferably, the supply air can be introduced into the working space starting from the upper surface of the housing. This makes it possible to obtain a uniform flow through the working space.In a preferred embodiment, it is provided that a gauze is arranged downstream of the supply air device in the flow direction, wherein the supply air can be introduced into the working space in the form of a laminar flow. A gauze is a very fine mesh fabric which allows the formation of a laminar air flow. A laminar air flow of supply air in the working space enables working without air turbulences. This prevents, for example, cross-contamination between a plurality of objects located in the work space or tools required for the machining. In addition to mechanical tools, the tools required for processing can also be chemical solutions, for example, which are required in particular for the analysis of substance samples or blood samples or the like.Preferably, the exhaust air from the exhaust air device is sucked through a work plate having a grid structure corresponding to the lower surface of the housing. This ensures a uniform air flow within the working space.The exhaust air is partly conducted out of the workbench and partly conducted back into the working space via an air supply element. The exhaust air conducted from the supply air element into the working space becomes the reused supply air. The proportion of reused supply air can be saved in prefabricated supply air.The supply air element is preferably arranged between the exhaust air device and the supply air device, so that the reused exhaust air is mixed with prefabricated supply air in the supply air device before the supply air is flowed into the working space. Preferably, the supply air element is arranged in such a way that the reused supply air is likewise conducted via a supply air filter. This is preferably the supply air filter of the supply air device. This ensures freedom from particles of the supply air flowing into the working space, which corresponds to the reused exhaust air together with prefabricated supply air.In a preferred embodiment, it is provided that a filter is arranged between the exhaust air device and the supply air element. This filter retains possible contaminants from the exhaust air that the supply air has taken up during the flow through the working space. In this case, it is preferably provided that the filter is adapted to the field of use of the workbench.If, for example, biological samples are examined and / or biological work is carried out, it is advantageous to use a filter which filters microorganisms out of the air. In particular, it is advantageous here if a particulate (HEPA=high efficiency particulate air) filter or a high-performance particulate (ULPA= ultralow penetration air) filter is used.In an alternative embodiment, it is provided that an activated carbon filter is used as the filter. Activated carbon can absorb chemical substances, in particular vapors and volatile substances, from the exhaust air and thus free the exhaust air thereof before it becomes the reused supply air.If the exhaust air is partly led out of the workbench and partly led back into the workspace via an air supply element, such a workup step by means of a filter ensures that no cross-contamination occurs between the different objects located in the workspace and, in addition, the user is protected from the recirculation of substances harmful to health. This is advantageous in particular in chemical operations and in the semiconductor sector.The exhaust air device preferably comprises an exhaust air pipe in which a fan is provided. The fan draws the exhaust air from the working space.In the exhaust pipe, a branching section is provided, which divides the exhaust pipe into at least two sub-pipes. As a result, it is possible to split the exhaust air into a first partial exhaust air stream, which is led out of the workbench, and a second partial exhaust air stream, which is led back into the working space via the supply air element.This branching section is preferably designed as a T-tube.For regulating the exhaust air quantities of the first and second exhaust air substreams, regulating flaps are arranged in the sub-tubes, which regulating flaps are controllable. This allows a targeted control of which exhaust air quantity is guided from the workbench and which exhaust air quantity is recirculated to the working space via the supply air element.The supply air element is preferably designed as a pipe section which is designed to be fluidically connected to the second sub-pipe of the exhaust air pipe which conducts the second exhaust air sub-stream, and to the working space. This allows the return of the exhaust air, which is to be returned into the working space, from the exhaust air pipe and the adjoining partial pipe into the working space. At the moment at which the exhaust air is at least partially guided back into the working space, it becomes a reused supply air.The regulating flaps can preferably be automatically regulated by means of servo motors. The adjusting motors are adjusted and, via this, the division of the amount of exhaust air into the exhaust air partial streams mentioned is preferably carried out directly by a user. As a result, the user can regulate the quantity of recirculated exhaust air and exhaust air led out of the workbench depending on the work to be carried out in the workspace.In an alternative embodiment, the regulating flaps are preferably automatically regulated as a function of the exhaust air quality. For this purpose, the exhaust air quality is determined by means of a sensor. If the exhaust air quality decreases excessively, the regulating flaps in the two sub-pipes must be adjusted in such a way that more exhaust air is guided out of the workbench. In contrast, more exhaust air can be returned to the working space if the exhaust air quality indicates that no or only hardly any impurities are in the exhaust air.In a preferred embodiment, it is provided that the exhaust air device is regulated in such a way that at least 50% of the extracted exhaust air can be introduced into the working space via the inlet air element. As a result, at least 50% of the exhaust air is returned to the working space as reused supply air. This enables a reduction of the prefabricated supply air quantity by at least 50%, whereby the energy required for the pre-assembly is also reduced by approximately 50% and the energy efficiency is significantly improved.Preferably, the exhaust air device is regulated in such a way that at least 70% of the extracted exhaust air can be introduced into the working space via an inlet air element. This makes it possible to achieve a further reduction in the quantity of prefabricated supply air and the energy required for this purpose. In addition, the remaining residual amount of exhaust air, which is led out of the workbench, ensures sufficient filter regeneration, so that no high chemical concentrations occur in the filter and the recirculated exhaust air. This is ensured in particular if substantially 30% of the exhaust air is guided out of the workbench.After the work in the working space has been completed, the regeneration of an activated carbon filter requires only a few minutes with an exhaust air flow separation between exhaust air returned into the working space and exhaust air led out of the workbench of 70:30.In a preferred embodiment, the supply air quantity and the exhaust air quantity, which is flowed into the working space by the supply air device and is suctioned out of the working space by the exhaust air device, can each be controlled separately from one another. In this case, in particular, the amount of supply air and / or exhaust air is controlled via control flaps in the corresponding supply air and / or exhaust air devices.In the simplest case, the supply air quantity preferably corresponds to the exhaust air quantity, wherein the reused supply air, which is guided back into the working space via the supply air element, must likewise be added to the supply air quantity. In order to avoid pressure fluctuations due to an open working opening or a user performing work in the working space, a pressure sensor is preferably provided in the working space, which measures the pressure in the working space and controls the regulating flaps in the supply air device and the exhaust air device relative to one another in such a way that atmospheric pressure prevails in the working space. This ensures that there is no positive or negative pressure in the working space, which would lead to an outlet of exhaust air into the environment of the workbench or a drawing in of ambient air from the environment of the workbench. This could contaminate the user or the object to be processed.In a preferred embodiment, it is provided that the air circulation in a closed state of the working opening is reduced by at least 30% compared to the air circulation in regular operation, particularly preferably by at least 50%. A closed state of the working opening is present when no work takes place in the working space and the working opening has been closed. Consequently, in this state, there is also no need for a full amount of supply air and exhaust air corresponding to the air circulation during operation. The air circulation corresponds to the amount of supply air and exhaust air which pass through the workbench in a defined time interval. This can further improve the energy efficiency.Preferably, it is automatically registered by means of a sensor which is arranged in the region of the working opening, in particular by means of a light barrier or a light curtain, whether working is being carried out in the working space. In this way, measures which increase further energy efficiency, for example a reduction in the air circulation and / or an increase in the amount of exhaust air fed back into the working space, can be initiated.In a preferred development, it is provided that the sensor and / or the light barrier and / or the light curtain do not register anything over a specific time interval and / or is not interrupted that the working opening is automatically closed and the air circulation is reduced by 30 to 70%, in particular by 50%, compared to the regular air circulation during operation. This can be effected, for example, by moving the front slide down into a closed position. Preferably, the time interval corresponds to 20 minutes.Furthermore, it is preferred that the air circulation is further reduced if, for example, no work takes place in a time interval greater than 24 h or if weekend is. In these cases, the air circulation is preferably reduced to a maintenance mode which corresponds to less than 30% of the air circulation during operation.In a preferred development, the workbench can be expanded as a modular system. In this way, certain requirements which exist as a function of the respective working range can be fulfilled. The modular system can provide, for example, a second workspace that is connected to the workspace via a feedthrough. Alternatively, special immersion basins can be arranged within the working space, which allow certain working steps, for example immersion washes. Operating elements outside the workspace for media proportioning in the workspace can also be expanded.In a preferred embodiment, the side surfaces and / or the front surface are transparent. This makes it possible to carry out work in the working space easily and conveniently.The workbench preferably has a digital interface. This allows digital networking of, for example, a plurality of workbenches arranged in a room, in particular in a clean room, among one another and / or with the laboratory, the building or the ventilation system. If only a part of the workbenches is operated, the air circulation in the further workbenches can be automatically reduced. This ensures compliance with the simultaneity factor and this can be reduced to the most necessary. This further improves the energy efficiency. If, on the other hand, a safety-relevant occurrence or an energy-saving state occurs, for example at night or at the weekend, a simultaneous and / or mutual closing and / or locking of the workbenches, the laboratory and / or the building can be triggered, for example. This results in a further drastic increase in energy efficiency.In addition, the object is achieved by a method for operating a workbench, having a working space surrounded by a housing, an air supply device with which prefabricated air supply is introduced into the working space, and having an exhaust air device with which exhaust air is extracted from the working space, wherein it is provided that the exhaust air is partially guided out of the workbench during regular operation and is partially guided back into the working space as reused air supply via an air supply element. Regulating flaps are used to control which amount of exhaust air is guided out of the workbench and which amount of exhaust air is recirculated to the working space via the supply air element. As a result, less prefabricated supply air is required, so that energy costs are saved and the energy efficiency of the workbench is increased.The regular operation corresponds to an operation in which work is performed within the workbench without a very high chemical or other contamination load occurring.Preferably, the quantity of supply air that is guided into the working space via the supply air device and the supply air element corresponds substantially to the quantity of exhaust air that is guided out of the working space. This leads to a compensation of the amount of air flowing into the working chamber and extracted, whereby essentially atmospheric pressure prevails in the working chamber. This ensures that no contaminants can enter the working space from outside it and vice versa.In a preferred embodiment, it is provided that 70% of the exhaust air is guided via the supply air element as reused supply air back into the working space. This allows an improved energy efficiency of the workbench to be achieved.In a preferred development, the exhaust air, which is recirculated to the working space via the supply air element as reused supply air, is filtered before recirculation to the working space, in particular filtered by an activated carbon filter. This removes chemicals or other contaminants from the exhaust air before it is returned to the working space.Preferably, in the case of a safety-relevant treaty, the exhaust air is guided completely out of the workbench. A safety-relevant occurrence is, for example, an uncontrolled evaporation of potentially hazardous substances or some other escape of above-average increased amounts of substance. If the exhaust air is guided completely out of the workbench, this corresponds to 100% of the exhaust air. Thus 0% of the exhaust air is returned to the working space. This setting is optionally automatically adjustable by a user manually or by means of a sensor. A corresponding control results in an adjustment of the control flaps of the exhaust air device, wherein the flap of the partial pipe, which can guide the exhaust air back into the working space, is completely closed.Features of the device mentioned in the description can be transferred to the method and method features to features of the device.Further features, details and advantages of the invention are evident from the wording of the claims and from the following description of exemplary embodiments on the basis of the drawings. The following are shown: FIG. 1 is a lateral sectional view of a workbench, FIG. 2 is a lateral sectional view of a workbench with flow arrows, FIG. 3 shows a front view of a workbench.FIG. 1 shows a lateral view of a workbench 1 with a housing 2, which forms a working space 3 and surrounds the same. The working space 3 can be engaged through a working opening 4. This working opening 4 is embodied such that it can be closed by means of a closure element 5. This closure element 5 is formed in the present example by a front slide 6. The housing 2 comprises two lateral surfaces 7, of which only one is visible in the sectional view of FIG. 1, a rear surface 8, a front surface 9, an upper surface 10 and a lower surface 11.By means of an air supply device 12, air which is prefabricated during operation is flowed into the working chamber 3. In this case, it can be provided that the supply air passes a supply air filter 13 before entering the working space 3, which filters out particles. By means of an exhaust air device 14, the supply air is extracted as exhaust air after flowing through the working space 3. The exhaust air is partly led out of the workbench 1 and partly fed back into the working space 3 via an air supply element 15. For this purpose, the exhaust air device 14 has an exhaust air pipe 16 which comprises a branching section 17 at which the exhaust air pipe 16 is separated into two partial pipes 18. In the sub-pipes 18 at least one regulating flap 19 is arranged in each case, with which the ratio between the exhaust air led out of the workbench 1 and the exhaust air fed back into the workspace can be regulated. In the partial pipe 18 which carries the exhaust air partly back into the working space 3, a filter 20 is preferably arranged. This filter 20 can comprise activated carbon, for example.As shown in FIG. 1, a monitor and operating unit 21 can optionally be arranged on the housing 2 of the workbench 1, which monitor and operating unit displays, for example, the parameters of the workbench, the supply air and / or exhaust air, and also serves for setting and regulating the regulating flaps and further components not shown. The components not shown also include fans, which flow the supply air into the working space 3 and extract it from it as exhaust air.Below the working space, a substructure 22 is arranged, which is designed, for example, as a storage and / or safety cabinet 22. This substructure 22, like further elements, can be modularally adapted according to customer skill.FIG. 2 also shows a lateral sectional view of the same workbench as FIG. 1 with flow arrows. The supply air device 12 flows prefabricated supply air via a supply air filter 13 into the working chamber 3, which takes place in FIG. 2 starting from the upper surface 10.Work can be performed on the lower surface 11. The exhaust air device 14 draws the exhaust air out of the working space 3 through the lower surface, which has a permeable grid structure. In the branching section 17, the exhaust air is divided into a first exhaust air stream, which is guided from the workbench, and a second exhaust air stream, which is returned to the working space 3 again as reused supply air.FIG. 3 shows a front view of a workbench 1, which is of modular construction and has, in addition to the workspace 3, a second separate workspace 23, for example for the consumption of chemicals. The working space 3 and the second working space 23 can be connected via closable passages. The passage is closable by means of a slide or a door. The exhaust air of the second working area 23 is set during the consumption of chemicals in such a way that the exhaust air is completely led out of the second working area 23 and is not reused. Below the workbench 1, a cabinet is provided as a base 22.The invention is not limited to one of the above-described embodiments, but can be modified in many ways.All features and advantages which emerge from the claims, the description and the drawing, including structural details, spatial arrangements and method steps, can be essential to the invention both individually and in a wide variety of combinations.List of reference characters1 Workbench 2 Housing 3 Working space 4 Working opening 5 Closure element 6 Front slide 7 Lateral surfaces 8 Rear surfaces 9 Front surface 10 Upper surface 11 Lower surface 12 Supply air device 13 Supply air filter 14 Exhaust air device 15 Supply air element 16 Exhaust air pipe 17 Branching section 18 Partial pipes 19 Regulating flaps 20 Filter 21 Monitor and operating unit 22 Substructure 23 Second working area

Claims

Workbench (1) having a working space (3) surrounding a housing (2), wherein the working space (3) can be engaged through a working opening (4), having an air supply device (12), by means of which prefabricated air supply can be introduced into the working space (3), and having an air exhaust device (14), by means of which air exhaust can be extracted from the working space (3), wherein the air exhaust device (14) is designed such that air exhaust can be at least partially discharged from the workbench (1) and can be at least partially introduced into the working space (3) via an air supply element (15), characterized in that the air exhaust device (14) has an air exhaust pipe (16), which comprises a branching section (17), at which the air exhaust pipe (16) is separated into two sub-pipes (18), wherein at least one regulating flap (19) is arranged in each of the sub-pipes (18), with which the ratio between exhaust air led out of the workbench (1) and exhaust air fed back into the workspace can be regulated.Workbench according to Claim 1, characterized in that the supply air device (12) has a supply air filter (13).Workbench according to one of the preceding claims, characterized in that a gauze is arranged downstream of the supply air device (12) in the flow direction, wherein the supply air can be introduced into the working space (3) in the form of a laminar flow.Workbench according to one of the preceding claims, characterized in that a filter (20), in particular an activated carbon filter, is arranged between the exhaust air device (14) and the supply air element (15).Workbench according to one of the preceding claims, characterized in that the exhaust air device (14) can be regulated in such a way that at least 50% of the extracted exhaust air can be fed into the working space (3) via an inlet air element (15).Workbench according to one of the preceding claims, characterized in that the exhaust air device (14) can be regulated in such a way that at least 70% of the extracted exhaust air can be fed into the working space (3) via an inlet air element (15).Workbench according to one of the preceding claims, characterized in that a pressure sensor is arranged in the working space (3).Workbench according to one of the preceding claims, characterized in that a sensor, in particular a light barrier and / or a light curtain, is arranged in the region of the working opening (4).Workbench according to one of the preceding claims, characterized in that the working opening (4) is designed such that it can be closed by means of a closing element (5), wherein a seal is arranged in particular on the working opening (4) and / or the closing element (5), said seal sealing the working space (3) in a closed state of the working opening (4).Workbench according to one of the preceding claims, characterized in that the workbench (1) has a digital interface.Method for operating a workbench, having a working space (3) surrounding a housing, an air supply device (12) with which prefabricated air supply is flowed into the working space (3), and having an air discharge device (14) with which air discharge is extracted from the working space (3), wherein the air discharge is, during regular operation, partly led out of the workbench (1) and partly led back into the working space (3) as reused air supply via an air supply element (15), characterized in that it is controlled by means of regulating flaps which amount of air discharge is led out of the workbench and which amount of air discharge is led back into the working space via the air supply element.Method according to claim 11, characterised in that 70% of the exhaust air is guided via the supply air element (15) as reused supply air back into the working space (3).Method according to either of Claims 11 and 12, characterized in that the exhaust air, which is recirculated to the working space (3) via the supply air element (15) as reused supply air, is filtered before recirculation to the working space (3), in particular filtered by an activated carbon filter.Method according to one of Claims 11 to 13, characterized in that, in the event of a safety-relevant agreement, the exhaust air is guided completely out of the workbench (1).

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