Abstract: There is disclosed a building energy system comprising a building enclosure having an interior and exterior. The building enclosure comprises an insulated building envelope that incorporates perimeter windows with a centre-of-glass R-value of R-4 or higher, at least one upper exhaust outlet and at least one lower supply intake that connect to the exterior of the building enclosure, and at least one central space that is connected to the lower supply intake and one or more perimeter rooms located adjacent to the central space. Each perimeter room comprises one or more lower wall vents that connect to the central space, and one or more upper vents connected to the upper exhaust outlet. The upper exhaust outlet incorporates a regulator to minimize ventilation air heat loss while maintaining indoor air quality. The regulator may comprise an automated damper and a motorized fan selectively operated based at least in part on measurements of air pollution contaminants.

Abstract: The invention concerns a method of adjusting a room air in a first room wherein the room air is supplemented continuously or at recurring intervals of time by nitrogen or a nitrogen-bearing, carbon dioxide-poor gas mixture in such a way that the proportion of oxygen in the room air is less than 20.9% by volume and the proportion of carbon dioxide of the room air is less than 1% by volume, wherein at the same time at least a slight overpressure in relation to an outside atmosphere surrounding the room is set in the room.

Abstract: The present invention provides a ventilation system for a perishable goods store and a method of operating a ventilation system for a perishable goods store. The system of the present invention may monitor and control the temperature and humidity of the goods within the store and comprises a controller for automatically operating the system, a duct through which air is propelled into the store, pressure control means for controlling the pressure within the duct and a pressure monitoring means for measuring the pressure within the duct. The controller monitors the pressure within the duct and controls the pressure control means ensure the air pressure within the duct is maintained within a defined pressure range. The pressure control means may comprise at least one variable speed fan. The present invention is advantageous in that it optimises the back-pressure within the duct, against which the at least fan must act, thereby providing a more efficient ventilation system.

Abstract: The present invention is a mobile air contaminant control system that includes a filter assembly enclosed by a mobile outer chamber. The filter assembly is tapered to create a large volume air way downstream from the filter assembly that enables more even air flow and filter loading. One or more exhaust fans pull the air through the filter assembly and exhaust it to the exterior of the chamber. The system is functionally attached to an exterior structure having at least one air intake and housing a work piece. As airborne contaminants are generated from the work piece(s), the control system exhausts them from the exterior structure through the filter assembly and into the external environment.

Abstract: A crawlspace encapsulation system for encapsulating a crawlspace of a building. The system includes a substantially impermeable barrier layer disposed in the crawlspace and isolating at least a portion of the crawlspace from an outside atmosphere and an air circulation system located in the isolated portion.

Abstract: A device for generating a negative pressure in the sealed room of a tablet press and/or of an isolator, with a fan connected to the sealed room and an air opening towards the sealed room, wherein the intake side of an ejector is connected with the sealed room, the working fluid connection of which is connectable with a compressed air source via a valve, with a sensor which is connected to a negative pressure control unit which opens the valve when the sensor measures a pressure in the sealed room which is above a predetermined negative pressure value, a second valve being assigned to the fresh air inlet opening, which depending on the embodiment remains opened or is triggered and closed by the negative pressure control unit.

Abstract: A method and system for minimizing an incomplete closing phenomenon between an elevator hole and an interior section and a stack effect problem such as strong wind generated when opening an elevator door, which are inevitably generated at upper floors of high-rise office buildings, are provided. The method includes determining a degree of pressurization of the interior section in accordance with target pressure resistance and reduction in passing wind when opening the elevator door, and calculating a supply air volume required for the pressurization and an exhaust air volume from an elevator shaft based on the determined degree of the pressurization.

Abstract: A return fan control system for an HVAC system comprises a supply fan control loop, a return fan control loop and a building pressure control system. The supply fan control loop comprises a duct pressure controller arranged to control a supply fan to a duct pressure setpoint. The return plenum pressure control loop comprises a return plenum pressure controller arranged to automatically control a return fan to a return plenum pressure setpoint determined by a setpoint reset function. The building pressure control system is operable to control a building pressure. The building pressure control system may comprise a building pressure control loop and an outside air control loop cooperatively arranged to control an exhaust damper in response to an outside air intake.

Abstract: An air-pressure-control system, the system comprising a system inlet, a system outlet, and a variable-speed fan configured to operate at a speed. A motor controller in communication with the fan is configured to control the speed of the fan. A differential-pressure transducer configured to monitor an air pressure at the system inlet and an air pressure at the system outlet. A closed-loop pressure controller in communication with the motor controller and differential-pressure transducer, wherein the pressure controller is configured to vary the speed of the fan based on the pressure differential between the inlet and outlet of the system, thereby controlling a pressure within a space. An ultraviolet kill chamber may be disposed between the inlet and outlet to expose airborne particulate to UV radiation. The system may also have a filter located within an air-flow path between the system inlet and system outlet.

Abstract: An air conditioning apparatus including a heater or furnace includes a controller for receiving control signals from a thermostat and from a user interface for initiating a contingency mode of operation when a signal from the thermostat is not available. The user interface includes a visual display and multiple keys for entering the contingency mode which includes selecting a capacity of heat output of the apparatus and a duty cycle. The user interface may be disposed in the apparatus cabinet and connected directly to a microprocessor based controller for the apparatus. The contingency mode is automatically aborted if a fault signal is received by the controller, a signal is received from a thermostat or power to the apparatus is interrupted.

Abstract: A rack and method of cooling wherein cold, sub ambient air is introduced into an electronic enclosure from below. In some embodiments a plurality of parallel arrange air movers pushes cold air to a series of ducts. Axial flow fans, or other types of fans, are secured to where cold air enters the ducting. Cold air is ducted to cabinets through at least one large plenums. The size of the duct allows for large amounts of cold air to move at low velocity and to travel through two parallel ducts into a large plenum. An even distribution of cold air is directed towards the exhaust through a screen. One side of the plenum is open to the equipment to be cooled. A screen evens out the pressure distribution of cold air along the length of the plenum prior to exhaust.

Abstract: An air-pressure-control system, the system comprising a system inlet, a system outlet, and a variable-speed fan configured to operate at a speed. A motor controller in communication with the fan is configured to control the speed of the fan. A differential-pressure transducer configured to monitor an air pressure at the system inlet and an air pressure at the system outlet. A closed-loop pressure controller in communication with the motor controller and differential-pressure transducer, wherein the pressure controller is configured to vary the speed of the fan based on the pressure differential between the inlet and outlet of the system, thereby controlling a pressure within a space. An ultraviolet kill chamber may be disposed between the inlet and outlet to expose airborne particulate to UV radiation. The system may also have a filter located within an air-flow path between the system inlet and system outlet.

Abstract: A vent for a lamp enclosure comprises a passageway between the interior and exterior of the enclosure, a non-planar vent element covers the passageway. The vent has improved air flow and offers splash protection against liquids.

Abstract: A system and method for determining “real time” air leakage from a duct involves an airflow meter for taking airflow measurements at the inlet and at the outlet of the duct. Also included is a base fan that operates in three different modes to simultaneously vary an enclosure pressure at the inlet and outlet. This is done while a duct fan, inside the duct, is operated to continuously move air through the duct. A comparison of airflow measurements at the inlet, or at the outlet, under the three base fan operational modes will respectively identify whether leaks are present in the duct, upstream or downstream from the duct fan.

Abstract: An apparatus for maintaining a desired air pressure inside a home includes a differential pressure switch/gage having a first port and a second port. The first port is adaptable for sensing a first pressure inside the home; the second port is adaptable for sensing a second pressure outside the home. The differential pressure switch/gage is adaptable for producing a signal in response to a difference between the first pressure and the second pressure. A motorized damper is in signal communication with the differential pressure switch/gage and is operable to control entry of air into the home in response to the signal. A method of maintaining a desired air pressure inside a home comprises sensing a first pressure inside the home, sensing a second pressure outside the home, and introducing air into the home through a controlled opening if said second pressure exceeds said first pressure by a specified amount.

Abstract: A pressurization control system configured to regulate air pressure within a space includes a first damper fluidly coupled to an air supply, the first damper configured to control delivery of an air flow, and a second damper having an operating range, the second damper fluidly coupled to the air supply and the first damper, the second damper configured to supplement delivery of the air flow. The pressurization control system further includes a room controller configured to provide a control signal to the first and second dampers, wherein the control signal drives the first damper to direct the air flow towards the operating range, and wherein the control signal drives the second damper to direct the air flow towards a set point.

Abstract: An air conditioning system includes a controller for controlling the feed rate of air from a blower such that the inside of the operator's cab is at higher pressure than outside pressure when a pressurization mode for pressurizing the inside of the operator's cab is selected, a branch duct opening/closing damper device is provided for distributing the air from the blower to an air outlet directed to an operator and an air outlet undirected to the operator (i.e., a defroster air outlet). Further, the controller controls the branch duct opening/closing damper device such that the air is ejected from the air outlet directed to the operator in such a volume that makes the operator have comfortable cool or warm feeling whereas the remaining volume of air is ejected from the defroster air outlet, when the difference between the inside air temperature of the operator's cab and a preset temperature becomes small.

Abstract: The invention refers to an explosion protection system for electrical apparatuses and machineries, such as manipulators or industrial robots, located in hazardous environments, i.e. environments containing explosive concentrations of inflammable gases, dusts or vapours, comprising an air supply that applies internal pressurized air into an explosion proof enclosure. The invention is achieved by a flow- and pressure sensor arranged as an integrated unit and designed to stand high dynamic forces by having low inertia, balanced arrangement of moving parts and a movement guide, e.g. an axle with a support guide, with low friction.

Abstract: A self balancing air handling system for conditioning an interior space includes an air handling unit having an outlet for supplying conditioned air to the space, an entrance providing an access from an exterior space to the interior space, an air plenum surrounding said space, and an inlet for returning air from said plenum to said air handling unit wherein said air handling unit supplies said conditioned air under conditions providing a positive pressure differential at said entrance between the interior space and the exterior space thereby limiting infiltration air into the interior space.

Abstract: A method for controlling flow rates of outdoor air supplied to a room and room air discharged to an outside of the room in ventilation. The method of the present invention includes the steps of supplying outdoor air drawn through an air supply duct to a room at a first flow rate, and discharging room air drawn through an air discharge duct to an outside of the room at a second flow rate higher than the first flow rate. The first and second flow rates vary with rotation speeds of fans respectively mounted on an air supply duct and an air discharge duct.

Abstract: A method of controlling a variable-air-volume heating, ventilating, and air-conditioning system, includes causing the static pressure in a duct to be maintained at a desired static pressure by controlling the speed of a fan in proportion to the square root of the ratio of a desired duct static pressure setpoint to a measured duct static pressure. A HVAC system employing the method is further included.

Abstract: An air velocity sensing system not requiring external power supply is applied to an air duct system, comprising: (1) a sensor module disposed in the air duct for measuring the air velocity therein and for saving the measured air velocity value; and (2) a control module for wirelessly transmitting a signal to the sensor module, which sends the measured air velocity value back to the control module after receiving the signal from the control module, so as to have the air velocity value displayed on control module. The present invention also provides an air velocity sensing method not requiring external power supply.

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: An air-pressure-control system, the system comprising a system inlet, a system outlet, and a variable-speed fan configured to operate at a speed. A motor controller in communication with the fan is configured to control the speed of the fan. A differential-pressure transducer configured to monitor an air pressure at the system inlet and an air pressure at the system outlet. A closed-loop pressure controller in communication with the motor controller and differential-pressure transducer, wherein the pressure controller is configured to vary the speed of the fan based on the pressure differential between the inlet and outlet of the system, thereby controlling a pressure within a space. An ultraviolet kill chamber may be disposed between the inlet and outlet to expose airborne particulate to UV radiation. The system may also have a filter located within an air-flow path between the system inlet and system outlet.

Abstract: Systems and method for controlling the flow of air through a mechanical draft system are disclosed herein. A pressure controller for controlling air pressure comprises an appliance controller configured to control the operation of a plurality of appliances, an intake fan controller configured to control the speed of an intake fan, and an exhaust fan controller configured to control the speed of an exhaust fan. The pressure controller also includes a processor configured to receive a differential pressure signal and to control the operation of the appliances, the speed of the intake fan, and the speed of the exhaust fan in response to the differential pressure signal.

Abstract: A pressurization control system configured to regulate air pressure with a space includes an air supply source fluidly coupled to a damper, a room controller configured to provide a control signal to the damper. The room controller includes a flow controller configured to generate a flow feedback signal, and a pressure controller configured to generate a pressure feedback signal, wherein the room controller is configured to receive flow and pressure feedback signals and generate the control signal based on one or more of the received flow and pressure feedback signals.

Abstract: A gas pressure regulator (100) includes a mechanical primary stage (102), preferably including a spring valve, and an electronic secondary stage (104), preferably including a micromachined pressure regulator, the combination of the mechanical primary stage and the electronic secondary stage suitable for relatively precise low pressure near zero flow rates with reasonable energy consumption rates, such as encountered when supplying fuel to a low power fuel cell system.

Abstract: A device for controlling airflow between a clean room (1) and an adjacent room (2) is described. Channels (10, 6) lead from the rooms (1, 2) to a common junction (8). A ventilation channel (9) is leading from the common junction (8) for feeding or carrying off air. In the channel (10) from the clean room (1) is included a resistor element for the airflow, while the channel (6) from the adjacent room (2) has low hydraulic impedance.

Abstract: A method and apparatus for removing airborne contaminants in residential or commercial buildings injects filtered air into these enclosures. Prior to be injected in these enclosures, the air is filtered for chemical, biological or radioactive hazards. The filtering of the air ensures that the enclosure is a safe haven. The apparatus includes an enclosure, a filtration assembly for removing airborne biological, chemical or radioactive agents mounted with the enclosure. A series of expansion slots can be mounted within the enclosure to assembly a multi-stage filtering process. A blower is also included in the apparatus for overcoming the resistance of the filtration assembly and increases the air pressure inside the building to achieve protective overpressure. A control system within the apparatus monitors the pressure and adjusts the airflow in the system in order to maintain the protective overpressure.

Abstract: A method for controlling building interior air pressure that is different from external environment air pressure, wherein the internal and external air pressure difference can be significantly large. The internal and external air pressure difference is maintained through partitioning the internal airway using permeable porous walls. A method for building the permeable porous walls using unit permeable porous blocks including boxes of granular particulates is provided to ease not only the installation but also the repair and replacement of the permeable porous walls, and also to maximize the reusability of the materials used to build the walls.

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 gas pressure regulator (100) includes a mechanical primary stage (102), preferably including a spring valve, and an electronic secondary stage (104), preferably including a micromachined pressure regulator, the combination of the mechanical primary stage and the electronic secondary stage suitable for relatively precise low pressure near zero flow rates with reasonable energy consumption rates, such as encountered when supplying fuel to a low power fuel cell system.

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: An environmental monitoring and controlling system for a ventilated cage and rack system that monitors and measures air flow in the rack at either the rack or cage level. At the rack level, two pressure sensors are provided in a supply air system to accurately monitor the air flow rate into the rack. In addition, two pressure sensors may be provided in an exhaust air system to accurately monitor the air flow rate out of the rack. At the cage level, a cage may be equipped with a highly accurate pressure sensor, including a Venturi tube and thermistor, the monitor the air flow rate in a cage located at any cage position in the rack.

Abstract: Method to operate a combustion device in a house or similar building, with fossil fuel furnaces, such as wood or oil furnaces. Outdoor air is supplied to a heat exchanger that is connected to the smoke tube of the furnace, in such an amount that an interior excess pressure is created, as excess air is led out of the interior of the building through one or more exhaust openings, especially exhaust devices, which are located at low places in the building at its outer side. This offers better combustion efficiency, better energy-utilization and a more uniform temperature in the building. A device for operating the method, comprises a fan (23) which takes in air from an inlet (19) near the outer walls of the building, through a tube (24) leading to the furnace, with a heat exchanger (33, 34) enclosing some of the smoke tube (18) of the furnace (17). The fan (23) is dimensioned and operated to create an overpressure in the building.

Abstract: An apparatus and a method for environmental control in a process chamber, and specifically, in a spin coating chamber are disclosed. In the apparatus, an air velocity control system which consists of a pressure sensor, a throttle valve controller and a throttle valve is utilized for controlling the air velocity in a spin coating chamber, and specifically in a drain cup of a spin coating chamber. The present invention apparatus enables a novel method for reducing the air velocity in a spin chamber for achieving a more accurate process control, while maintaining a substantially constant humidity level in the process chamber. Frequently observed large fluctuations in the humidity and temperature in an air flow that is flown into the process chamber are thus minimized or eliminated. The present invention novel method and apparatus allows a spin coating process, and specifically a SOG spin coating process, to be carried out with improved accuracy and reliability.

Abstract: A central vacuum cleaner system having a motor driven vacuum source which is selectively turned on or off. The central vacuum cleaner has an interface connector for establishing a connection between the central vacuum and an air exchanger. The interface connector is connected to be activated by the central vacuum when the motor is turned on so as to activate the air exchanger.

Abstract: An automatic control system for providing pneumatic purging protection for a sealed enclosure containing electrical equipment in accordance with the National Fire Protection Association standards. The system supplies a purge gas under a pre-ordained pressure to an enclosure residing in a hazardous location. The system monitors the gas pressure to maintain the pressure within desired limits. In the event that the integrity of the sealed enclosure is disrupted, the control system disables the electrical equipment and executes a rapid-response purge cycle to re-enable the electrical equipment as quickly as possible.

Abstract: The present invention provides a gas vent system for a vacuum chamber. The particle placed onto the wafer after loading out from a vacuum chamber can be greatly reduced by the system design. The gas vent system has a gas supply, an anti-vibrating tube, a gas regulator, a first line, a second line, a vent valve, and a filter. The anti-vibrating tube is connected after the gas supply for transferring gas without introducing vibration. The gas regulator is connected after the anti-vibrating tube for controlling a flow rate of the gas. The first line is connected after the gas regulator and has a first metering valve. The second line is connected after the gas regulator and is also connected in parallel with the first line. The second line has a second metering valve and an in-line valve in series. The vent valve is connected after the first line and the second line. The filter is connected between the vent valve and the vacuum chamber.

Abstract: A controller for heating, ventilating and air-conditioning distribution systems, which includes 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 temperature during a heating or cooling operation in a controlled space.

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: A system controls the pressure at which conditioned is to be provided to one or more zones to be heated or cooled by the conditioned air. The system actively computes a setpoint for the pressure with a location in a duct system upstream of where any of the conditioned air is to be provided to the zones. The setpoint is computed as a function of the positional statuses of dampers within the duct system that regulate the flow of the conditioned air to the respective zones. The actively computed setpoint is compared with a sensed pressure in the duct system in order to determine whether the pressure in the duct system needs to be changed.

Abstract: A paint spray booth (10) has a spray chamber (11), an air make-up unit (15), and an air exhaust system with an exhaust air fan (26) and an exhaust damper (25). The booth has a pressure transducer (29) that senses the pressure of air both inside and outside the booth and which transmits control signals indicative of sensed changes in the differential air pressure to motors that drive the exhaust fan or the exhaust damper. In this manner the exhaust air flow rate is adjusted to compensate for changes in the differential air pressure.

Abstract: A pair of variable air volume fans and a set of primary and exhaust air diffusers are in atmospheric communication between a supply of ventilation air that employs the principles of thermal displacement ventilation for purging a designated smoking area of smoke pollutants and the outside atmosphere for receiving the purged polluted air. The volume of ventilation air supplied to the designated area and the volume of air exhausted from the designated area is based upon air quality demand requirements and is determined by a microprocessor coupled to a gas sensor disposed within the designated smoking area.

Abstract: A self-contained ventilation apparatus is disclosed for ventilating buildings, e.g., patient rooms such as hospital rooms, waiting rooms, hospital operating rooms, doctors' offices, and clinics, especially rooms contaminated with infectious microorganisms. One or more blowers is provided. When there are two blowers, a first blower is provided for discharging room air to the atmosphere and a second blower is provided for introducing fresh outside air to the room to provide a continuous supply of fresh air to the room which is free of disease organisms. Both streams of air pass through an air-to-air heat exchanger to adjust the temperature of the incoming air to approach that exhausted from the room. When filters are used, both currents of air are preferably filtered, e.g., with a high efficiency particle air (HEPA) filter. Provision is made for automatically maintaining room air pressure at the desired value (typically below that of surrounding rooms) as filters gradually become clogged with dust.

Abstract: An adjustable damper for controlling air flow from one area to another includes a rectangular frame forming an opening with a number of movable vanes positioned to selectively close off or open up the opening. Positioned between each pair of vanes in the frame is a stationary pitot-static sensing vane. Each pitot-static sensing vane can also be shaped as an air foil and includes an upstream chamber connected to a ram air input aperture and a downstream chamber connected to a downstream static aperture. Each of the chambers is connected to one portion of a pressure sensing instrument, such as, for example, a diaphragm type differential pressure sensor, in order to sense air flow velocity across the damper.

Abstract: An apparatus and method for space pressure control in high containment laboratories. The system comprises a volumetric air flow controller and a differential pressure controller. The differential pressure controller couples to the volumetric air flow controller. To establish negative space pressurization in the laboratory, the differential pressure controller generates a variable offset signal for volumetric operation. In response to the offset signal, the volumetric air controller controls the ducted supply air to the laboratory at a set shortfall compared to the ducted exhaust air flow. The shortfall of ducted supply air creates a negative pressure which is also sensed by the differential pressure controller. The differential pressure controller reduces the variable offset signal to zero once the desired negative pressure level is attained. To maintain the negative pressure level, the supply and exhaust air flow rates must remain equal.

Abstract: A swimming pool room air conditioner has a duct with an inlet return for air drawn from the pool room and a supply air blower downstream from the inlet of the duct for the blower to draw air through the duct and supply it to the pool room after the air is conditioned. The duct inlet, an evaporator coil for cooling and dehumidifying return air, an air reheat condenser coil and the supply blower are arranged in the duct in the stated order. A motor controlled damper is arranged for bypassing return air around the evaporator coil and thereby cause a predetermined humid return air flow over the evaporator. An exhaust blower is provided. A motor controlled warm air damper is arranged for allowing the exhaust blower to draw a fraction of the return air before the return air flows over the dehumidifier evaporator coil and discharges the fraction to outdoors. A cool air damper is arranged for the exhaust blower to exhaust a fraction of the cooled air to the outdoors.

Abstract: A control device for operating drive motors of closure devices that is reponsive to air pressure differential inside and outside an enclosure and including a housing that will extend through a wall of the enclosure, vanes in the housing and adjustably weighted linkage interconnecting the vanes outside the housing and, depending upon the position of the linkage, operating sealed switches to actuate the drive motors.