Abstract: An apparatus (10), including a gas recirculation circuit comprising a mini environment chamber (14), a gas pump (16), a filter assembly (22) which are connected by a recirculation channel (20). The apparatus additionally includes an air supply conduit (18) for supplying air to the gas recirculation circuit and having an air supply conduit inlet (18a) which opens into the ambient air and an air supply conduit outlet (18b) which opens in the recirculation circuit. In use, a mini environment chamber pressure (Pme) is maintained higher than the ambient pressure (Pam). The gas recirculation channel (20) includes a substantially frictionless recirculation restriction embodied as a throat (30). At downstream end of the throat which forms the narrow part of the throat, in use, the static pressure is below the ambient pressure. The air supply conduit outlet opens at the downstream end (30a) of the throat.

Abstract: An extraction hood of the up-and-down type for extracting fumes and/or vapours generated on a hob includes a fixed first hood portion (2) and a second extraction hood portion (4) set at a distance from the first extraction hood portion (2) and close to the hob, the second hood portion containing an extraction device (6) capable of drawing in air containing fumes and/or vapours from the hob and directing it towards an opening (11) in the second hood portion (4) to be discharged therefrom and passed towards the first hood portion (2). A conveyor (10) for the discharged air is provided at the opening (11) of the second hood portion (4). The conveyor includes a body (30) having a tubular annular shell (31) containing a honeycomb structure (32) with a number of tubular cells (42) through which the air leaving the second hood portion (4) is discharged.

Abstract: Disclosed is an equipment front end module (EFEM) in which wafer transfer is conducted between a wafer storage device where a wafer is stored and a process chamber. In addition, the EFEM generates gas flow in a wafer transfer chamber.

Abstract: A reduced-pressure treatment system for treating a wound on a patient includes a composite manifold that may help prevent or minimize injury to a wound edge of the wound being treated with reduced pressure. The composite manifold includes a perimeter manifold member and an inboard manifold member. The perimeter manifold member is designed to not collapse substantially under reduced pressure in a therapy range. The perimeter manifold member may be more rigid with respect to compressibility than the inboard manifold member. A sealing member is used to form a fluid seal over the wound, and a reduced-pressure subsystem provides reduced pressure to the composite manifold. Other systems, methods, and dressings are presented.

Abstract: A device for dispersing foul gaseous effluent emissions released diffusely by sources located close to the ground, in particular by wastewater treatment ponds (10, 11, 12), includes: at least two auxiliary air or gas injectors (5a1, 5b1; 5a2, 5b2; 5a3, 5b3) oriented upwards and installed in opposing zones on the periphery of each foul gaseous effluent source, such as to disperse the gaseous effluents; separate supply elements (8.1, 13a1, 13b1; 8.2, 13a2, 13b2; 8.3, 13a3, 13b3) for the injectors; and wind-direction-sensitive control elements for ensuring that at least the injector(s) best located to disperse and/or lift the gaseous effluent plume are supplied.

Abstract: Disclosed herein are several embodiments of a wound treatment apparatus employing a fluidic connector for negative pressure wound therapy and methods of using the same. Some embodiments are directed to improved fluidic connectors for connecting to a wound site, for example a fluidic connector including a reinforcement, and methods of using the same.

Abstract: A reduced-pressure treatment system for treating a wound on a patient includes a composite manifold that may help prevent or minimize injury to a wound edge of the wound being treated with reduced pressure. The composite manifold includes a perimeter manifold member and an inboard manifold member. The perimeter manifold member is designed to not collapse substantially under reduced pressure in a therapy range. The perimeter manifold member may be more rigid with respect to compressibility than the inboard manifold member. A sealing member is used to form a fluid seal over the wound, and a reduced-pressure subsystem provides reduced pressure to the composite manifold. Other systems, methods, and dressings are presented.

Abstract: The present invention relates to a medicament delivery device comprising a housing (10), which housing (10) is arranged ranged to accommodate a medicament container (16), the device further comprises a drive mechanism (18) capable of, upon activation, expel a dose of medicament from said medicament container, the drive mechanism comprising a flat spiral spring (26). The invention is characterized in that at least a part (36) of an outermost turn of said flat spiral spring (26) is positioned on an outer surface of said housing (10).

Abstract: Provided is a temperature control apparatus of a working machine that is inexpensive, energy-saving and capable of eliminating the temperature difference between a temperature in a room in which the working machine is installed and a temperature of a working area.

Abstract: A range extractor hood includes a screen, at least one filter element and at least one pivot bearing which swingably supports the at least one filter element on the screen. At least one locking member retains the at least one filter element to the screen. Located on the screen is a releasing device for, at least partially, releasing the locking member and retention of the filter element.

Abstract: Grease filtration systems suitable for use on the rooftop of a building are disclosed. Methods of making and using grease filtration systems are also disclosed.

Abstract: A ventilator is provided for removing contaminants from the air around a client in a beauty salon. An overhead canopy pushes fresh air downwardly towards the client, while suction means is provided for drawing away the downward flow of air and entrained contaminants so as to minimize exposure of the client to the contaminants. In a preferred embodiment, the ventilator is designed for use in a hair salon and the client wears an exhaust collar that is provided with air inlets positioned so that the flow of air is drawn away from the client's face, minimizing exposure of the client to the contaminants.

Abstract: The invention relates to an extractor apparatus (10), in particular a laboratory extractor apparatus, with a working area (13) and with a fan arrangement (26) for generating an air flow (27) or an inlet opening for an air flow (27) for the removal of gases and/or particles from the working area (13) and with at least one surface bordering the working area (13). The extractor apparatus (10) has charging means (30) for ionising the air flow (27) and/or for electrostatic charging of at least one surface.

Abstract: A system for ridding the working area of a nail salon work station of fumes and nail dust. The system is self-contained within the particular work station and has a vacuum system that draws air in from the area surrounding and proximate the working area to remove the fumes and dust. A fan draws that air into a chamber containing a bag-type, particulate filter that filters out the nail dust. Downstream of the bag-type filter is a fume filter that receives the air from the bag-type filter, having been pressurized by the fan, and provides a filter of the fumes. The air, now having passed through a particulate filter and a fume filter is exhausted into the room at a location remote from the working area. The bag-type filter is inexpensive and readily replaced.

Abstract: A low depth telescoping downdraft ventilator controlled by an electronic controller providing a precisely controlled and efficient way of removing gases and fumes is disclosed. The low depth telescoping downdraft ventilator has the ability to fit behind a built-in oven placed below a cook top unit. The telescoping downdraft ventilator has an almost infinitely selectable range of heights above a cook top with a built in oven. The ventilator collects and draws in exhaust fumes and smoke, filters it and re-circulates or expels it either outdoors or indoors. The inner member of the telescoping ventilator may house the exhaust fans and may move up or down without the use of mechanical switches for elevation detection and stopping. The ventilator may have sensors to detect temperatures, filter change need, fan speeds, telescoping stop points, energy consumption, resistance and voltage, enabling programmable set point operation.

Abstract: The present invention relates to a welding booth that has a small foot print and can be joined to other booths for maximization of floor space use.

Abstract: A low pressure blow-off assembly provides converging airflow around a length of material moving through the assembly. The assembly generally includes a body having an interior wall and an exterior wall. The interior wall defines a bore extending through the body for receiving the material through the body, and the exterior wall surrounds the interior wall and defines an air reservoir within the body generally between the exterior wall and interior wall. A cap is configured to be coupled to the body to cover at least part of the air reservoir. The bore includes a generally tapered end and the cap includes a generally tapered inner lip, where the tapered end of the bore and the tapered inner lip of the cap define an opening therebetween for discharging air from the air reservoir through the opening in a generally converging airflow pattern around the material passing through the body.

Abstract: A dust shroud assembly for a power tool includes a shroud portion, a barrel, and a helical spring. The barrel includes an upper portion slidably received within a first end portion of the shroud portion. The barrel defines a helical channel. The helical spring is at least partially rotatably engaged with the helical channel and rotationally fixed with respect to the shroud portion. The helical spring is configured to bias the barrel outwardly from the first end portion.

Abstract: An air deflector of an extractor hood, wherein the air deflector has two components to divert air, which is extracted from a chamber by the extractor hood back into the chamber. The air deflector also has a plug connector to connect the two components to each other in a detachable or non-detachable manner.

Abstract: An exhaust system for a plasma cutting machine which uses an outside air supply to provide needed airflow to a cutting table thereof is disclosed. Airflow into the cutting table may be controlled and directed to select zones of the cutting table.

Abstract: A chamber facility includes: an air supply unit which supplies clean air to the inside of a chamber; an air supply port section which has one end communicating with the air supply unit and the other end opened into the chamber; and an air exhaust unit which exhausts air within the chamber from an exhaust port formed at a lower position of the chamber, wherein the air supply port section has a plurality of air supply port units which generate rotational flow around a vertical axis within the chamber.

Abstract: An arrangement for the sterile, aseptic production and/or filling of pharmaceutical products contains a housing which, with the exception of an inlet and an outlet with a clearly defined cross-section, is closed in an airtight manner. Through the air inlet air is forced via a filter into the interior of the housing. The air passes out of the housing through the air outlet or channels. The size of the cross-section of the air outlet and the performance of the ventilating device are matched in such a way that within the interior of the housing there is a laminar unidirectional or combined airflow and a constant overpressure with respect to the pressure outside the housing.

Abstract: A mobile laminar flow hood specifically devised for use in podiatry and a podiatric apparatus to which such hood is associated are described. The hood is adapted to generate a laminar flow of sterile air. In particular, an apparatus comprising a system for the generation and treatment of a laminar air flow in a intervention zone is described, together with means to support the system for the generation and treatment of a laminar air flow. The system comprises a blowing hood adapted to generate a laminar flow of sterile air towards said intervention zone, and a suctioning hood adapted to suck the laminar flow of sterile air from the intervention zone.

Abstract: The invention relates to an apparatus, in particular for processing toxic and/or medical media, including a closed-off work chamber, in which the medium can be manipulated. A ventilating device delivers a particle-free or laminar or turbulent air stream to the work chamber. A return air conduit communicates with the work chamber via an outlet opening and by way of which air is carried away from the work chamber. A cleaning element is disposed in the work chamber, to enable cleaning of the work chamber and of the return air conduit. At least one blocking device blocks off an additional connecting portion between the work chamber and the return air conduit. The blocking device is able to be opened for cleaning of the return air conduit.

Abstract: An integrated system of preparing wheel surfaces and maintaining air circulation in a mobile enclosure is provided. The system could include a first compartment having a wheel rotating apparatus configured to rotate a wheel about an axis. The system could also include an air circulation system to filter pollutants from the outside environment before drawing air into the mobile enclosure. The air circulation system could also filter pollutants inside the mobile enclosure before releasing air outside of the mobile enclosure through an opening disposed on the floor of the mobile enclosure.

Abstract: A ventilation unit that can be sealed to an opening in a large temporary overspray enclosure employed during the painting of large yachts and marine vessels for containment of paint overspray, thereby substantially eliminating overspray in surrounding areas, a long sought-after objective in the industry. The unit is compact and self-contained, having a pre-filter area, primary filter material, an intake area, fans, a variable controller for each fan, an exhaust area, final discharge filters, and doors configured to seal the back end of ventilation unit during periods of non-use and which are removable during use or otherwise positionable to provide unobstructed airflow into the pre-filter area. The unit is also configured to be easily portable and reusable. A hose connection plate can also be used to connect one or more hoses to the pre-filter area to provide enhanced ventilation to high paint areas within the temporary overspray enclosure.

Abstract: A low pressure blow-off assembly provides converging airflow around a length of material moving through the assembly. The assembly generally includes a body having an interior wall and an exterior wall. The interior wall defines a bore extending through the body for receiving the material through the body, and the exterior wall surrounds the interior wall and defines an air reservoir within the body generally between the exterior wall and interior wall. A cap is configured to be coupled to the body to cover at least part of the air reservoir. The bore includes a generally tapered end and the cap includes a generally tapered inner lip, where the tapered end of the bore and the tapered inner lip of the cap define an opening therebetween for discharging air from the air reservoir through the opening in a generally converging airflow pattern around the material passing through the body.

Abstract: A method and apparatus for applying an atomized liquid solution upon a person, comprising a spray enclosure booth; an exhaust vent located below an anticipated user's facial area zone, the exhaust vent disposed within the bottom tray or a lower area of at least one wall or a lower area of a door and configured for exhausting ambient atomized liquid solution from the spray enclosure booth; a rigid conduit support defining a central air flow conduit connected to a bottom tray and pneumatically connected to an exhaust vent and providing structural integrity to the enclosure booth; an atomizing spray head assembly movably connected to the rigid conduit support and physically supported by the rigid conduit support; and an exhaust system configured to exhaust ambient atomized liquid solution from the spray enclosure booth by drawing atomized solution into the exhaust vent then through and out of the rigid conduit.

Abstract: An apparatus for manufacturing semiconductor devices includes: a cabinet having an opening section on a front surface thereof; a front door that is provided at the opening section of the cabinet in a manner to be freely opened and closed; a low oxygen gas intake port for introducing nitrogen gas or gas with an oxygen concentration lower than a concentration of oxygen contained in an air atmosphere; a gas exhaust port for exhausting the gas from within the cabinet; a ventilation system that introduces the air atmosphere or oxygen into the cabinet; a lock system that is capable of locking the front door in a closed state; and a detector that detects oxygen concentration within the cabinet, wherein the lock system unlocks the front door when the oxygen concentration detected by the detector becomes a predetermined value or higher.

Abstract: A controlled environment cabinet comprises a working chamber made up of clear panels and a stainless steel frame. Two frontal panels may be raised on hinges to access an interior of the chamber. Working armports are provided, closed by a flexible membrane, which is slit such that an operator may pass an arm into the chamber, but the membrane closes around the arm, restricting airflow out of the chamber. An air treatment unit is supplied with air from the chamber by a fan/filter unit. The air treatment unit can raise or lower the temperature and relative humidity of the air, and the fan/filter unit contains a HEPA filter to remove particulates suspended in the air. The treated air is passed back to the chamber. Controls are provided, whereby a desired temperature, humidity and air flow rate or rate of atmosphere exchange within the chamber may be set.

Abstract: An air curtain-assisted exhaust method and a device thereof are provided. Air curtain generators are disposed on a worktable to enclose an encircled area in the worktable. A receiving hood is disposed above the worktable, wherein the vertical lower part of the outer edge of the receiving hood completely covers the encircled area. Then, the air curtain generators are started to blow out air curtains toward an opening of the receiving hood, and the receiving hood is started to suck an air flow. A shielding space is defined by the air flow sucked by the receiving hood and the air curtains, so that the air curtains may guide a smoke generated inside the shielding space to the receiving hood to be exhausted, thereby achieving the effect of auxiliary exhaust, and may restrict the smoke in the shielding space to prevent the smoke from diffusing laterally.

Abstract: The method for salon air purifying comprises the following steps: (a) categorizing contaminants generated in the salon; (b) selecting air purifiers such that each air purifier is most effective in capturing a specific category of contaminants; (c) detecting which category of contaminants is being generated; (d) activating the air purifier that would most effectively capture the specific contaminants being generated and deactivate other air purifier(s) if not needed. Applying the aforementioned method, the apparatus for salon air purification comprises: (a) detectors to detect which category of contaminants are being generated, (b) two different air purifiers: one for capturing chemical fumes and the other for capturing filing dust and (c) a controller to receive the detectors' data, to activate air purifier only when airborne contaminants are present and to select which air purifier to activate based on the detectors' data.

Abstract: An atmosphere control apparatus includes an air introducing mechanism which introduces air from an air introducing port, and a first impurity removing mechanism which removes impurities from the air. The air introducing mechanism is disposed between the air introducing port and the first impurity removing mechanism. By doing this, it is made possible to provide an atmosphere control apparatus which can prevent external atmosphere from entering a chamber containing a device-manufacturing apparatus so that the atmosphere in the chamber can be controlled accurately.

Abstract: A safety workbench includes a work chamber enclosed by a housing, including a work opening located in the housing front side and settable using an adjustable front pane to let in an external air flow flowing into the work chamber, and including at least one fan for delivering the external air flow into the safety workbench. To improve the working conditions of the safety workbench for operators while simultaneously ensuring sufficient personal protection at all times, a regulating unit and/or a control unit is provided, by which the delivery output of the at least one fan can be regulated and/or controlled as a function of the front pane position.

Abstract: A ventilation system for use with a cooking appliance to maintain an atmospheric pressure balance existing within an enclosed space surrounding the cooking appliance. A hood establishes a three-dimensional and interiorly recessed configuration and which is supported above the appliance. A filter within the hood communicates with a vacuum driven exhaust extending from the enclosed space. A supply plenum secures in downwardly and opposing fashion relative to a side of the cooking appliance. An air intake communicates the supply plenum with an exterior environment, the plenum terminating in an upwardly angled outlet for introducing intake air along the side of the appliance, resulting in heating and elevating the intake air within a perimeter defined by the hood and thereby minimizing loss of conditioned air existing within the enclosed space.

Abstract: An apparatus for reducing a relative humidity of air inside an enclosed space includes a portable outside air heat exchanger unit having a fan operative to create an air stream by drawing outside air from an intake and discharging the air stream through an outlet inside the enclosed space, and a temperature adjusting element located in the air stream. A heating source supplies heat energy to the temperature adjusting element in response to directions from a heat controller. A humidity sensor is operative to sense the relative humidity of the air in a sensing location and to send a humidity signal to the heat controller to change the amount of heat energy supplied to the temperature adjusting element in response to the humidity signal. HEPA filters and ultra-violet lights can shine on the air stream to kill mold spores and the like.

Abstract: A securing device for a filter element, which can be detachably mounted on an extractor hood, has a connecting implement for detachably connecting the filter element to the associated extractor hood. The connecting implement catches the filter element when detaching the filter element from the extractor hood and prevents it from falling down. The connecting implement has a fixing element with a rod-like section and with a thickening connected thereto. The connecting implement also has a closure element with a U-shaped slot. The rod-like section of the fixing element is formed so that it fits the U-shaped slot of the closure element.

Abstract: An adjustable roof jack adapted for mounting on a flat or pitched roof. The roof jack is connected to a lower end of an air discharge duct from an air conditioning unit and to the top of an air supply duct in the roof. The roof jack includes an angular-shaped sheet metal lower frame member having a front side, back side, a first side and second side. A lower portion of the sides of the lower frame member is received around the top of the air supply duct. Also, the lower portion of the sides of the lower frame member is integrally formed into to an outwardly extending roof flange. The roof jack also includes an angular-shaped sheet metal upper frame member having a front side, a back side, a first side and second side. A top portion of the front side of the upper frame member is hinged to a bottom portion of the front side of the upper frame member.

Abstract: A movable spray-painting stand includes a worktable provided with four casters and having a wind-exhausting device and a filtering device assembled thereon. The wind-exhausting device has an air inlet communicating with the wind outlet of the filtering device. A separating device is provided in front of the wind inlet of the filtering device to form a spray painting space. A collapsible work frame is pivotally assembled with the work table and positioned under the separating device, able to be positioned in the spray painting space after articles to be spray painted are placed on its upper plate. The spray painting stand can be moved around freely, and the exhaust and the odor of paint produced during spray painting can be filtered by the filtering device, conforming to environmental protection and ensuring workers' health.

Abstract: The invention relates to a hood (10) for a filter ventilator, which is connected to an outside wall (40) of a space to be ventilated, in particular the outside wall (40) of a control box, circuit housing, or case for various kinds of devices, and which includes an air inlet (11), an air outlet (12), a filter (20) mounted in the air outlet and a maintenance portal (13), in particular for exchanging the filter (20). In order to enable effortless and rapid exchange of the filter, the maintenance portal (13) is made such that it can be closed by at least one pivotable flap 30.

Abstract: An improved smoke evacuation system (10), a method for removing gaseous byproducts of surgical procedures, and noxious vapors from chemicals, is provided. The smoke, and vapor evacuation system includes a vacuum head (18) positioned at a surgical site or incorporated into a workstation. The vacuum head includes a plenum (28), a plenum support for preventing the plenum from collapsing when a vacuum or low pressure is established therein, and is adapted to facilitate the use of the system in a variety of surgical or commercial procedures at a variety of surgical sites or commercial workstations.

Abstract: An adjustable roof ventilator jack for operationally coupling a roof ventilator to a venting aperture extending through a sloped roof. The jack includes a base section having base section front, rear and side walls. The base section is configured so as to be angled in a direction opposite the slope of the roof. The jack also includes a pivotable section having pivotable section front and side walls. The pivotable section front wall is pivotally attached to the base section for pivotal movement between an extended configuration wherein the pivotable and base section front walls are in a substantially parallel relationship relative to each other and a retracted configuration wherein the inner surface of the pivotable and base section front walls form an obtuse angle. The jack further includes a position lock for selectively locking the base and pivotable sections in a predetermined angular relationship relative to each other.

Abstract: A dust extraction shroud for a drill, which surrounds a drill bit and which lies adjacent the work surface, comprises a body portion defining a first inlet adapted to engage the work surface and to surround the location at which said bit penetrates the surface. The shroud body further defines a first outlet connected to a source of suction and a third inlet for allowing the bit to pass through said body portion. A first sealing means is arranged in said third inlet for surrounding said bit and resisting the flow of air. Wherein said body portion includes at least one protruding portion defining a second inlet between said protruding portion and an adjacent part of said body, and on a side of said protruding portion remote from the first inlet. The second inlet admits air to enter said body portion and travel to the first outlet.

Abstract: In a dentist's surgery, a treatment room, and premises where different chemicals are handled or where welding or soldering is performed there are a number of pollutants. In accordance with the invention, these pollutants are removed by an endless air-jet circuit (5), which during its course passes a treatment locus as well as a filter.

Abstract: A robotic welding station cleaning assembly (10) for removing particulates from an air-filled chamber surrounding a welding robot (12). A frame (14) is positioned about the robot (12) and includes a top (20) defining an opening (26) therein. A shield (28) is supported by the frame (14) to define the robot chamber. A spark arrestor (48) is supported on the frame (14) for controlling sparks created by welding. A blower housing (30) having an inlet (27) is disposed immediately above and in direct fluid communication with the opening (26) to move air from the chamber to the blower housing (30). The frame (14) includes a separate support stand (32) for supporting the blower housing (30) on the top (20) of the chamber.

Abstract: A tornado type air intake and blowing device has an exhaust port communicating with an exhaust duct, an air supply chamber which is provided so as to surround the exhaust port and to which air is supplied through an air supply inlet, and air blowing ports blowing air supplied into the air supply chamber by swirling the air from the outer periphery of the exhaust port diagonally downward, the air blowing ports being provided in a side wall part of the air supply chamber, whereby the exhaust port can be formed in the entire area of the lower opening surface of the air supply chamber, the outside diameter of the air supply chamber is sufficient if it is equal to an outside diameter corresponding to the required opening diameter of the exhaust port and, accordingly, a device body can be formed compact.

Abstract: A compact, portable, lightweight, low power consuming, convenient, versatile and sterile laminar airflow device, useful in obtaining a workspace substantially devoid of airborne particulate contaminants, said device having a body (C) divided into an upper and lower chambers; the upper chamber housing one or more pre-filtration members (B), a motor (T) driving a fan (S), and one or more filters (U) located below the motor; and the lower chamber provided with a slideable front panel (M), a removable platform (X) located at the lower portion of the chamber and a perforated plane (N) placed on the removable platform.

Abstract: A suction and exhaust device wherein air is supplied as air curtain flow through air outlet (3) while the air surrounded by the air curtain flow is sucked through suction ports (2b) to be exhausted. A supply space in the device is divided into two chambers, upper and lower, by a partition plate (41): a first supply air space (4c) on the upper side into which air from the supply air duct (5) is introduced and a second supply air space (4d) which spreads in the direction of the air outlet (3). The first and second supply air spaces (4c, 4d) are communicated with each other through annular flow equalizing channel (40R, 50R) of small channel diameter vertically extending in the outer periphery of the suction duct (3). This uniformalizes the flow rate distribution of the supply air flow from the air outlet and forms a stabilized air curtain flow.

Abstract: A room ventilator for venting smoke exhaled by a smoker from a room to an exterior location. The room ventilator has an intake unit located in the room for drawing in smoke exhaled by the smoker, an air pump for producing an air flow to draw the smoke into the intake unit and exhausting the smoke to the exterior location, a connecting tube for connecting the intake unit to the air pump, and a window outlet adjuster for mounting in a window which enables a connecting tube to pass from the room to the exterior location. The window outlet adjuster has adjustable flaps for forming a barrier between the room and the exterior.

Abstract: A method and a system for the regulation of ventilation in a welding workshop, in which method the volume of supply air and/or extract air in the ventilation of the welding workshop is regulated. The basis of regulation of the volume is the load imposed on the electric power network by the welding equipment, e.g. the electric power consumed. The system comprises a set of measuring equipment for generating a measurement signal corresponding to the load imposed by the welding equipment on the electric power network. A set of control equipment has been arranged to regulate the volume of supply air brought into the welding workshop via a supply air duct and/or the volume of extract air removed from the welding workshop via an exhaust duct so as to achieve a level of ventilation proportional to the impurity load.