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: The present invention is a fume hood capable of exhausting contaminant, having an air pipe in a sash and a suction slot corresponding to the air pipe deposed at the front rim of the bottom surface to obtain an air curtain, where contaminant is efficiently prevented from leakage and energy is saved.

Abstract: An amount of time that air has been delivered from an air handler to a space is tracked, and based on the tracked amount of time, at least one turn-on time or one turn-off time of the delivery of air from the air handler to the space is controlled. Other features relate, among other things, to controlling a replacement air vent, and to user interfaces.

Abstract: A space conditioning system for a building including production and occupied spaces provides precise control of exhaust and space conditioning equipment by taking into account multiple conditions and by using predictive control. The control method and system are illustrated by a commercial kitchen ventilation application.

Abstract: An exhaust control system (72) for a commercial or institutional kitchen exhaust system (32) is disclosed in which the exhaust fan speed is optimized for the amount of cooking heat and cooking by-product generated by the cooking units, as well as for comfort in the kitchen (12). Kitchen comfort is determined by sensing temperature, humidity, noxious gases, smoke, odor, or some combination thereof. In particular, exhaust air temperature can be used by the control system (72) to modulate fan speed from a minimum value to a maximum value based on the minimum and maximum temperatures that define a particular temperature span. During operation, the control system (72) continues to monitor environmental parameters of the kitchen (12) to determine if the current temperature span provides optimal performance. Upon determining that the current temperature span is no longer the optimal one, the control system (72) operates the exhaust system (32) according to a different temperature span.

Abstract: A fume hood optical sash sensing system for controlling the flow of air into a fume hood to maintain a constant face velocity by utilizing an optical sensing device mounted inside the fume hood that can sense the movement of a sash based on repeatable reflexive tape to produce an output control signal that corresponds to sash movement to produce desired airflow into the fume hood. The system includes an optical sensing device with a light source, reflexive tape with a repetitive, quadrature encoded pattern, a smart controller device that receives output control signals from the optical sensing device, and an actuation device capable of receiving the output signal from the controlling device to control the damper device that will result in constant face velocity across the face of the sash.

Abstract: A method and apparatus for controlling a fume hood. A containment condition, i.e., a condition that may affect containment of potentially harmful substances in the hood, may be detected, and information regarding the detected condition sent by wireless signal. A fume hood controller may control at least airflow in the hood base on the information contained in the wireless signal.

Abstract: A method and apparatus for controlling a fume hood. A containment condition, i.e., a condition that may affect containment of potentially harmful substances in the hood, may be detected, and information regarding the detected condition sent by wireless signal. A fume hood controller may control at least airflow in the hood based on the information contained in the wireless signal.

Abstract: A fume hood exhaust stack system (10) and method utilize a variable speed fan (24) and an exhaust stack (28) having an adjustable cross-sectional area. Toxic exhaust from one or more fume hoods (12) is conveyed through a header (16) to the fan. The fan forces the exhaust through the exhaust stack, and the exhaust is then discharged into the atmosphere at a sufficient velocity and momentum to ensure that the exhaust reaches an environmentally sound altitude. A variable speed drive (36), programmable controller (34), flow signals (26), and static pressure and total pressure signals (20) are utilized to modulate the speed of the fan and the area of the exhaust stack to maintain the desired fan inlet pressure and exhaust velocity.

Abstract: Device for regulating the air volume flow for a laboratory exhaust, comprising

Abstract: A fume hood management system includes a collection section and a server apparatus. The collection section collects data representing an operation state from a plurality of fume hoods. The server apparatus includes an arithmetic section. The arithmetic section calculates a simultaneous utilization ratio on the basis of the number of simultaneously used hoods and the total number of fume hoods. The number of simultaneously used hoods is obtained from the data collected by the collection section and represents the number of fume hoods that are being used.

Abstract: A method and apparatus for controlling a fume hood. A containment condition, i.e., a condition that may affect containment of potentially harmful substances in the hood, may be detected, and information regarding the detected condition sent by wireless signal. A fume hood controller may control at least airflow in the hood based on the information contained in the wireless signal.

Abstract: A ventilation unit is provided comprising an electronically driven ventilator, mounted inside a casing wherein emerge several ducts connected to one or several rooms. Said unit further comprises orifices with specific cross-section, and a differential-pressure sensor measuring the difference in pressure between two predetermined points, said value being transmitted to an analysis and control device, which compares the differential pressure value to a reference value and controls the ventilator, such that it accelerates or slows down it rotational speed, so as to maintain the differential pressure constant and equal to the reference value, to maintain the desired flow rate at said orifices.

Abstract: A fume hood management system includes a collection section and a server apparatus. The collection section collects data representing an operation state from a plurality of fume hoods. The server apparatus includes an arithmetic section. The arithmetic section calculates a simultaneous utilization ratio on the basis of the number of simultaneously used hoods and the total number of fume hoods. The number of simultaneously used hoods is obtained from the data collected by the collection section and represents the number of fume hoods that are being used.

Abstract: A multi-stack exhaust system and method including at least one fume hood, multiple exhaust stacks, each stack having a return duct with a return damper and a discharge duct with a discharge damper, a fan, a flow sensor, a first static pressure sensor for measuring the static pressure at the inlet duct, a second static pressure sensor for measuring the static pressure at the at least two exhaust stacks, and a controller.

Abstract: A fume hood exhaust stack system (10) and method utilize a variable speed fan (24) and an exhaust stack (28) having an adjustable cross-sectional area. Toxic exhaust from one or more fume hoods (12) is conveyed through a header (16) to the fan. The fan forces the exhaust through the exhaust stack, and the exhaust is then discharged into the atmosphere at a sufficient velocity and momentum to ensure that the exhaust reaches an environmentally sound altitude. A variable speed drive (36), programmable controller (34), flow signals (26), and static pressure and total pressure signals (20) are utilized to modulate the speed of the fan and the area of the exhaust stack to maintain the desired fan inlet pressure and exhaust velocity.

Abstract: A ventilation system includes one or more exhaust fans and one or more make up air fans. Each fan has is driven by a motor operating at a constant speed. Each fan and motor are coupled by a torque converter, so that the torque applied to the fan is constant. Exhaust fan speed varies according to the ideal gas law, whereby the fan speed automatically varies in response to changes in system conditions, such as temperature and the associated changes in air density and resistance to the fan.

Abstract: The invention relates to a method and a device for separating at least two physical areas (1, 2) and for reducing the transmission of air-borne particles between said physical areas so as to protect persons and/or products (26) from said air-borne particles. The persons is located at least partly in the first physical area (1) and the products (26) in the second physical area (2) and at least one flat jet (13) of purified air is used to separate the two areas. The invention is characterized in that at least one low-turbulence displacement air stream (14) of purified air is generated at least in the second physical area (2) near the at least one air jet (13) and said at least one displacement air stream is directed primarily in the same direction as the at least one air jet (13).

Abstract: A multi-stack exhaust system and method including at least one fume hood, multiple exhaust stacks, each stack having a return duct with a return damper and a discharge duct with a discharge damper, a fan, a flow sensor, a first static pressure sensor for measuring the static pressure at the inlet duct, a second static pressure sensor for measuring the static pressure at the at least two exhaust stacks, and a controller.

Abstract: A sash position sensing system for a fume hood (10) and the like having a plurality of movable sashes (12a, 12b, 12c, 12d) in a frame includes an indicator element (24) affixed to each sash and an array (20) of sensor elements (22) extending along the frame. The sensor elements interact with the indicator elements when generally aligned therewith. The status of the sensor elements is captured in parallel without the need for multiplexing the sensor array, and a processor (52) reads the captured state information and calculates the open area of the frame. In further aspects, a method for determining the position of one or movable sashes in a frame and a fume hood employing the sash position sensing system of the present invention are also provided.

Abstract: A sash position sensing system for a fume hood (10) and the like having a plurality of movable sashes (12a, 12b, 12c, 12d) in a frame includes an indicator element (24) affixed to each sash and an array (20) of sensor elements (22) extending along the frame. The sensor elements interact with the indicator elements when generally aligned therewith. The status of the sensor elements is captured in parallel without the need for multiplexing the sensor array, and a processor (52) reads the captured state information and calculates the open area of the frame. In further aspects, a method for determining the position of one or movable sashes in a frame and a fume hood employing the sash position sensing system of the present invention are also provided.

Abstract: A fume hood control apparatus for controlling the flow of air through the fume hood in a manner whereby the effective size of the total opening to the fume hood, including the portion of the opening that is not covered by one or more sash doors will have a relatively constant average face velocity of air moving into the fume hood. The apparatus includes a simple and reliable sash door sensing means for sensing the position of the moveable sash door by using a rotary position sensor with a lever arm mechanism which translates horizontal or vertical movement to rotary movement for determining the position of the sash door. The apparatus compensates for nonlinearity that result from the translation.

Abstract: A generally closed lab hood having an opening closable by a movable door and connected to a variable-throughput suction source has a vent-control system having a sensor for detecting a velocity of flow of air into the hood and for generating an output corresponding to the detected velocity. A controller connected to the sensor and to the variable-throughput suction source receives the output and operates the suction source to set throughput of the source at a level corresponding to the output so that as the detected velocity increases the throughput of the suction source is increased and vice versa. The controller includes a sensor tube having an inner end opening into the hood and an outer end opening outside the hood and a sensor in the tube for detecting the velocity of air-flow therethrough. This tube is offset from the opening. The controller operates proportionally to set the throughput of the suction source relative to the air-flow velocity.

Abstract: A regulator is provided for maintaining a preset air velocity through the work chamber of a fume hood. The regulator compares a measured air velocity at the inlet into the chamber with a preset air velocity and adjusts air velocity in response to differences in measured and preset values. Air velocity is measured with a high sensitivity pitot with an exterior end to be positioned outside the fume hood, and an interior end to be positioned inside the fume hood. The pitot includes spaced parallel plates with front and rear ends, an exterior air pressure sensor positioned at the front end of the plates, and an interior air pressure sensor positioned at the rear end of the plates. The interior air pressure sensor includes openings substantially equidistant between the plates that are toward the rear of the pitot when the pitot is mounted on a fume hood. The exterior end of the pitot preferably curves below horizontal to minimize the effect of transient air currents.

Abstract: The present invention pertains to a system for controlling a fume hood with a face. The system comprises a device for controlling air flow through the fume hood based on air flow face velocity. The controlling device has a device for measuring pressure at the face of the fume hood which produces a signal corresponding to the pressure. Additionally, the system comprises a controller. The controller is remote from the fume hood controlling device but in communication with the controlling device. The present invention also pertains to a system for controlling a fume hood having a face. The system comprises a pitot tube assembly for determining a desired face velocity. The pitot tube produces a pitot signal corresponding to the face velocity. The system comprises a device for converting the pitot signal into a face velocity signal. The converting device is connected to the pitot tube. Additionally, the system comprises a processor for controlling air flow through the fume hood based on the face velocity.

Abstract: An airflow control valve for a clean room having a duct section with a damper positioned within the duct. The damper being capable of an adjustment from an open position to a closed position. The opening and closing of the duct is accomplished through a magnetic coupling such that the duct can remain sealed during operation. The airflow control valve includes a sensor for measuring the airflow rate, so that the duct can be adjusted to maintain one or more predetermined flow rate set-points.

Abstract: Apparatus for controlling the volume of air that is supplied and exhausted from a electronic semiconductor manufacturing wet bench is disclosed. The volume of air that is exhausted from the wet bench is increased during predetermined portions of the manufacturing process and is reduced during noncritical times as a function of predetermined conditions that may be detected or otherwise determined during the manufacturing process.

Abstract: The present invention relates to a safety valve for a containment (16) comprising a tubular body composed of a main branch (11) and a secondary branch (12) connected to said main branch (11) and opening into it via an aperture in the side of said main branch, a piston (13) mounted so that it slides inside said main branch (11) to free the said lateral aperture from the main branch, an upper stop (14) and a lower stop (15) both mounted inside the main branch and limiting the upward and downward displacement of said piston (13), the lower section of said main branch (11) being subject to a reference pressure, wherein an additional safety apparatus (25) is positioned under the tubular body between the lower section of said main branch and said reference pressure such that the maximum safety throughput rate of which the valve is capable is released in the event of an incident.

Abstract: An exhaust system has an air exhaust duct having a charge opening and a discharge opening and defining an air flow path. A damper is mounted in the duct for maintaining a constant air velocity for air exiting the discharge opening. The damper has opposing damper blades pivotally mounted within the duct. Each damper blade has an end that is pivotally mounted in cantilevered fashion within the duct so that an opposing end is free to move within the duct. Each damper blade is parabolic in shape and minimizes the air turbulence over the damper blade and reduces vibration. Each damper blade can be pivoted in response to a change in air volume discharged through the discharge opening to maintain a desired velocity of air through the discharge opening.

Abstract: A fume hood exhaust terminal for controlling gas flow in an exhaust duct has an electrically powered ultrasonic motor driven actuator for angularly positioning a damper in the terminal. The circuitry of the terminal includes a power failure detection circuit which includes the capability of storing sufficient power to place the damper in a preferred position until power is restored to the exhaust terminal.

Abstract: A controller for heating, ventilating and air-conditioning distribution systems, which includes a feedforward and feedback control strategies. The controller has a feedforward control strategy that generates a control signal based on control set points and identified characteristics of the system, and which adaptively adjusts such set points based on changes that are measured with respect to the identified characteristics. The controller is particularly adapted for controlling the differential air pressure in a controlled space relative to adjacent spaces.

Abstract: This invention continuously monitors the differential pressure between two environments, and dynamically adjusts the air handling system of the controlled environment to maintain a desired differential pressure setpoint by using a closed loop control methodology. Local and remote users can initialize, configure, monitor, and readjust the differential pressure setpoint as necessary. A differential pressure sensor transmits data to the system controller for processing and analysis. The system controller interfaces to a wide variety of air handling systems by using interchangeable air handling subsystems that plug into the invention. Each subsystem has the necessary hardware interface and software control methodology to easily and transparently enable the system controller to interface with a wide variety of air handling configurations.

Abstract: The present invention pertains to a system for controlling a fume hood with a face. The system comprises a device for controlling air flow through the fume hood based on air flow face velocity. The controlling device has a device for measuring pressure at the face of the fume hood which produces a signal corresponding to the pressure. Additionally, the system comprises a controller. The controller is remote from the fume hood controlling device but in communication with the controlling device. The present invention also pertains to a system for controlling a fume hood having a face. The system comprises a pitot tube assembly for determining a desired face velocity. The pitot tube produces a pitot signal corresponding to the face velocity. The system comprises a device for converting the pitot signal into a face velocity signal. The converting device is connected to the pitot tube. Additionally, the system comprises a processor for controlling air flow through the fume hood based on the face velocity.

Abstract: The flow of air through a fume hood is optimized by producing a bi-stable vortex within the vortex chamber of the fume hood regardless of sash movement. A bi-stable fume hood optimizes capture face velocity to minimize backflow of fume laden air through the hood sash opening. This bi-stable vortex fume hood reduces the energy consumption up to sixty percent versus the present day mono-stable vortex fume hoods. The bi-stable vortex fume hood utilizes a vortex pressure control system to reposition top, center, and bottom slot openings of a baffle in the hood. This baffle moves the bi-stable vortex away from the fact when the sash is fully opened and creates a clearing action near the work surface as the sash is closed. The fume hood's airfoil is placed inside the fume hood chamber and the airfoil has multiple entry pattern, one of which turns the vortex up and away from the open sash window. The other creates flow which washes the work surface of the hood.

Abstract: A fume hood controller includes detection apparatus for detecting the presence of objects within the fume hood and reduces the flow through the fume hood if there are no objects within the hood, thereby conserving energy costs associated with conditioning supply air to the room where the fume hood is located. The controller also adjusts flow as a function of the presence and also the location of objects that are detected within the fume hood. Since there is a smaller likelihood of fume spillage when the objects are located more deeply within the fume hood, the flow can be reduced in such a situation compared to that which would be required if the objects are located closer to the sash.

Abstract: A fume hood exhaust terminal for controlling gas flow in an exhaust duct has an electrically driven linear actuator for angularly positioning a damper in the terminal. Drive circuitry employed in the preferred embodiment prevents the possibility of shorting out the actuator motor in the event of an input signal condition which would attempt to operate the motor in two directions simultaneously. The circuit also includes a power failure detection circuit which includes the capability of storing sufficient power to place the damper in a preferred position until power is restored to the exhaust terminal.

Abstract: A system controller continuously monitors the differential pressure between two environments, and dynamically adjusts an air handling system of the controlled environment to maintain a desired differential pressure setpoint by using a closed loop control methodology. Local and remote users can initialize, configure, monitor, and readjust the differential pressure setpoint as necessary. A differential pressure sensor transmits data to the system controller for processing and analysis. The system controller interfaces to a wide variety of air handling systems by using interchangeable air handling subsystems that plug into the controller. Each subsystem has the necessary hardware interface and software control methodology to easily and transparently enable the system controller to interface with a wide variety of air handling configurations.

Abstract: A system for controlling laboratories having fume hoods comprising a network along which information is carried. The system is also comprised of a controller in contact with the network for receiving information from and providing information to the network. Additionally, the system is comprised of means for sensing a laboratory's state. The sensing means is disposed in each laboratory. There is additionally a microprocessor disposed in each laboratory for receiving information concerning the laboratory from the respective sensing means and the controller in order to maintain the laboratory in a predetermined state, and to provide information about the laboratory to the controller.

Abstract: Apparatus for monitoring the speed of movement of at least one sash door of a laboratory fume hood is disclosed. The speed of movement of a sash door is detected and an alarm signal is generated if the speed of movement exceeds a predetermined value while increasing the size of the uncovered opening of the fume hood.

Abstract: A system for optimizing the flow of air through a fume hood by dynamically controlling the air flow to provide a stable vortex in the vortex chamber of the hood, the optimum condition for minimizing backflow of fume-laden air through the hood doorway. A highly-sensitive pressure sensor disposed at a critical location in the vortex chamber sidewall senses minute variations in vortex pressure indicative of turbulence and sends signals via a transducer to an analog controller which uses proportional integral and adaptive gain algorithms to formulate output signals to an actuator which adjusts dampers in the hood to change the airflow into the vortex. The system operates in feedback mode and seeks a minimum in the amplitude of the sidewall pressure variations, indicating that turbulence has been eliminated and that a stable vortex exists. The pressure sensor signals can also be directed to an alarm to signal an off-standard and potentially dangerous condition.

Abstract: A clean air cabinet includes a blower chamber and a sample chamber separated by a filter. A blower within the blower chamber forces air through the filter into the sample chamber. A perforated wall between the sample chamber and the filter provides a pressurized zone between the wall and the filter. An exhaust plenum connects the pressurized zone with an exterior of the cabinet. A cap is provided to close off the plenum when the blower is not operating.

Abstract: A melt is converted into pieces by being converted to individual quantities that are dropped onto a cooling surface. Disposed above the cooling surface is a hood having a suction outlet for conducting waste air to a cleaner. Disposed in the hood upstream of the suction outlet is an arrangement of surfaces defining a serpentine flow path for the waste air so that a vaporous component of the waste air crystallizes on the surfaces. The surfaces are formed by plates mounted on a common transport carrier which periodically moves the plates against a scraper for scraping off the crystallized material. Alternately, the surfaces can be defined by endless belts which move against scrapers.

Abstract: A system for monitoring the operation of laboratory fume hoods includes a local area network for transferring data representing alarm conditions, and other special functions, to a building supervisory control system. The system has a calibrating capability which is adapted to build a database of the operating parameters of the fume hood which can be used to detect any degradation of the operation of the fume hood.

Abstract: A controller controls a prime mover (source component) in a heating, ventilation and air-conditioning (HVAC) distribution system. The controller determines a static pressure setpoint for the source component by first determining the pressure loss of each branch throughout the system. The controller then determines the pressure loss contributed by local components located within each branch of the system. The maximum of the branch pressure losses and the maximum of the component pressure losses are summed to provide the static pressure setpoint for the source component. The method provides control of the prime mover independent of the configuration of the system.

Abstract: A fume hood exhaust terminal for monitoring and controlling gas flow in a duct system includes a tubular duct segment having an upstream end, a downstream end, and an inner periphery, as well as an annular ring secured to the inner periphery between the upstream and downstream ends. A differential pressure transmitter device is disposed on the duct segment for measuring the pressure differential across the ring and for generating a corresponding flow signal. A damper is disposed in the duct segment between the differential pressure measuring device and the downstream end, and an actuator is located on the duct segment to be responsive to the signal generated by the differential pressure transmitter device and connected to the damper for selectively controlling the position of the damper in the duct segment to maintain a specified gas flow.

Abstract: A fume hood controller and method which compensates for resistance to air flow through a by-pass opening that exists due to a grille or louvre overlying the by-pass opening.

Abstract: A system for monitoring the operation of laboratory fume hoods is disclosed. The system includes a local area network for reporting alarm conditions and other data to a building supervisory control system. The system has a calibrating capability which is adapted to build a database of the operating parameters of the fume hood which can be used to detect any degradation of the operation of the fume hood.

Abstract: Precision gas flow control is provided utilizing a first coarse gas flow control element and a second fine gas flow control element. The second element is selected and operated to pass only a fraction of the flow passed by the first element. The elements may be connected either in series or in parallel so that at least a portion of the gas flow passes through each flow control element. Control circuitry is also provided which may be responsive at least in part to an indication of desired gas flow through the device for controlling the first element to provide a coarse gas flow adjustment and for controlling the second element to provide a fine gas flow adjustment. In some applications, only fine flow adjustment may be provided. Where the elements are being utilized for example as the tracking flow control elements for a sealed enclosure, either the fine flow control element or both elements may also be made responsive to pressure errors in the enclosure.

Abstract: An apparatus controls the face velocity of air flowing from a room into a fume hood. The fume hood includes a movable sash and an exhaust system. An air flow measuring device such as a parallel plate pitot is positioned within the fume hood between a pair of spaced apart air foils and outputs a signal that is representative of the air velocity between the air foils. An actuator controls the fume hood exhaust system in response to pitot output. Face velocity is maintained regardless of sash position.

Abstract: The apparatus may be implemented in software which performs the following steps: calculating a desired air velocity in the exhaust duct from a first input signal representative of the size of a variable sash opening and a first user defined setpoint representative of a desired face velocity; comparing successive values of the desired air velocity to determine any absolute and percent change therebetween; comparing the absolute change to a user defined reset deadband value; producing output signals, responsive to a second input signal representative of the measured air velocity in the exhaust duct and the second comparing step, for input to the fan so as to force the measured air velocity toward the desired air velocity. The production of the output signal is accomplished by adaptive, feedforward techniques when the absolute change is greater than the reset deadband and is accomplished by proportional/integral techniques when the absolute change is less than the reset deadband.