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.

Abstract: An air exchange system for use in commercial and residential buildings for monitoring the concentration of carbon monoxide or other gaseous components of air present in the building, and for removing the carbon monoxide from the air upon reaching a predetermined threshold concentration. The system utilizes standard carbon monoxide detectors located in rooms on all floors of the building which are electrically connected to a central control unit. When an excessive level of carbon monoxide is detected by one or more of the detectors, the control unit triggers shut-down of all potential sources of carbon monoxide within the building. The control unit simultaneously reverses the flow of air through the central heating/air conditioning system to remove the ambient room air and any carbon monoxide present at floor level and vents the room air to the outside of the building while bringing fresh air into the building.

Abstract: A crawl space ventilator includes a molded plastic self-contained support frame 20, with low voltage fan(s) 40 mounted therein. The frame 20 including a screened face plate 14 with adjustable hooks 22 or other such means for attachment to existing crawl space screens 12. On the upper surface of the frame 20 is a sloping rain guard 24, molded into the frame 20, to direct rain or irrigation water off the unit and vertical perforated tabs 26 on either side, that can break, off to allow for adjustment to for the ventilator to fit different sized vent screen 12 sizes. The tabs 26 have a secondary purpose, in that they have holes 27 that allow for nails or screws to penetrate through the holes 27 and into the foundation wall surrounding the crawl space opening 12, and is intended as an alternative method for installation.

Abstract: A holding cabinet with closed-loop humidity control system and method for controlling humidity in a holding cabinet are disclosed. According to an embodiment, the method comprises determining a relative humidity set point; activating a heater in a fluid pan; determining if a fluid is present in the fluid pan; measuring the relative humidity in the cabinet; and maintaining the relative humidity within a predetermined range. According to another embodiment, a holding cabinet with a closed-loop humidity control system includes a holding cabinet; an air temperature probe for measuring an air temperature within the holding cabinet; a humidity sensor for measuring a humidity within the holding cabinet; a heater for heating air within the holding cabinet to a predetermined temperature; an air fan for circulating the air and for introducing air from outside the holding cabinet; and a water pan for holding water within the holding cabinet.

Abstract: A room in a building serving as a safe haven for human inhabitants against harmful agent attack such as chemical or biological weapon attack. The room provides an environment sealed from air-carried harmful agents wherein the sealing can be accomplished by blocking air ducts and air leakage around doors. The room can be specially built, retrofitted, or rapidly adapted to serve as a safe haven. The room can include an oxygen source such as an oxygen generator. One oxygen generator utilizes a chemical process to generate gaseous oxygen. The room preferably includes a carbon dioxide scrubber. The invention includes kits and methods for rapidly converting a room to a safe haven.

Abstract: An indoor space is externally enclosed and thermally insulated by an underfloor insulating layer, a wall insulating layer and a ceiling insulating layer. An underfloor ventilation layer is defined between a floor and the underfloor insulating layer, and a ceiling ventilation layer is formed between a ceiling and the ceiling insulating layer. Communication is established through the underfloor ventilation layer, the indoor space and the ceiling ventilation layer, via floor vents and ceiling vents. Outdoor air is drawn into the indoor space from an air intake. Air is expelled from the ceiling ventilation layer into an underroof space by ventilation fans and then discharged outdoors from underroof outlets. A heat exchange ventilator is disposed in the ceiling ventilation layer, whereby heat exchange takes place between air in the ceiling ventilation layer and incoming fresh outdoor air. After the heat exchange, the incoming air is delivered into the underfloor ventilation layer.

Abstract: A system for controlling make-up air apparatus for a controlled building space includes a first sensor for sensing the operation of a first appliance within a building space. The appliance causes the air to be exhausted from the controlled building space. There is a controller which receives a first signal from the appliance indicating that the appliance is activated. This signal is used to determine the air flow requirements between the controlled building space and an environment outside of the controlled building space such as to ensure a predetermined balance of the pressure of air within the controlled building space and the environment outside of the controlled building space. An air temperature sensor monitors the outside temperature. A back-flow damper and a preheater are also associated with the make-up air apparatus. A switch activates the preheater in the event that the temperature of outside air is below a predetermined level. The motor of a blower causes air to be drawn into the building space.

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: A gas fireplace is provided having a plenum formed around at least a portion of the fireplace firebox. Room air enters the plenum and is heated by the firebox prior to venting back into the room. Two openings are provided from the outside of the fireplace housing to the plenum. The first opening allows heated air to exit the plenum, while the second opening allows cool outside air to enter the plenum. a mechanism is provided to control the amount of heated air exiting the first opening and the amount of cool air entering the second opening. By controlling the inflow and outflow through the first and second openings, respectively, the amount of the fireplace by-products generated into the room where the fireplace is located such as carbon-monoxide, nitrogen dioxide, heat and moisture are reduced.

Abstract: A gas fireplace is provided having a plenum formed around at least a portion of the fireplace firebox. Room air enters the plenum and is heated by the firebox prior to venting back into the room. Two openings are provided from the outside of the fireplace housing to the plenum. The first opening allows heated air to exit the plenum, while the second opening allows cool outside air to enter the plenum. a mechanism is provided to control the amount of heated air exiting the first opening and the amount of cool air entering the second opening. By controlling the inflow and outflow through the first and second openings, respectively, the amount of the fireplace by-products generated into the room where the fireplace is located such as carbon-monoxide, nitrogen dioxide, heat and moisture are reduced.

Abstract: An apparatus for increasing ventilation of heated and/or moisture-laden air from an attic or roof crawl space (12) in a dwelling or the like, a soffit fan (30) acts to accelerate natural convection by creating an air flow (16) from pulling cooler, denser outside air into attic space (12). The cooler air flow (16) displaces the heated and/or moisture-laden attic air; the attic air rises and is expelled through an opening at or near the top of a roof, preferably through a ridge opening (20) in a roof ridge ventilator (18).

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 ventilation-heating apparatus comprises a fresh air passage with which a fresh air ventilation mechanism is associated and which opens into a room-side inflow air supply opening. The ventilation-heating apparatus further comprises a room air passage with which a room air ventilation mechanism is associated and which opens into a room-side air removal outlet opening. Fresh air and room air passages are passed through a heat exchanger which is suitable for the transfer of heat from the room air passage to the fresh air passage. An electrically heatable metallic heating element is provided in the region of the fresh air passage. A suitable heat storage element is associated with the heating element for the storage of the heat produced. An electrically heatable metallic additional heating element which can be selectively switched on is provided in the region of the fresh air passage.

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: A heat exhaust system for installation in the space behind the refrigerator of a recreational vehicle for disposal of heat that builds up behind an RV refrigerator from the operation thereof. The system operates automatically to turn on a fan to dissipate the heat at a predefined high temperature, and operates automatically at a predefined low temperature to turn off the fan thereof.

Abstract: A detector in a space to be sensed and controlled gives an electrical signal upon fumes in the space reaching a predetermined level. An electrical circuit is thereby energized to operate a fan to exhaust the space. Inlet and outlet openings in the structure enclosing the space are biased closed but open in response to air pressure on operation of the fan. Also the main door is opened by mechanism actuated by the signal. When the main door is open, the circuitry for opening the main door is open, and there is no actuating the apparatus.

Abstract: A modular automatic power flow fresh air inlet comprising a housing having fresh air openings between a source of fresh air and a room, having an adjustable static pressure to be ventilated. The fresh air openings may be controlled by a valve plate pivotally connected to the housing at each opening. The valve plates pivot relative to the static pressure in the room. A cable having first and second ends extends through the housing and is connected to the valve plates via a lanyard. A cable control device for moving the cable between a forward position and a rearward position is connected to the first end of the cable. A cable counter weight is attached to the second end of the cable. Moving the cable toward the forward position places tension on the lanyard, causing the valve plate to pivot from the static position toward to the fully opened position. Moving the cable toward the rearward position relaxes the tension in the lanyard, causing the valve plate to pivot toward the static position.

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 gas venting system with an electrically operated exhaust fan used in an enclosed garage to expel unwanted gases, especially carbon monoxide, to outside the garage and away from an attached residence. In a garage with a door opener with an automatically operative light fixture, power to operate the electrically operative fan is supplied from the connected light fixture, via an interconnected relay, during the normal preset time interval the door opener's light is operating.

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: A system for maintaining a desired air flow through a fume hood having a sash. The system comprises a mechanism for controlling air flow through the fume hood based on at least one gain. The system is also comprised of a mechanism for automatically tuning the gain connected to the controlling mechanism. Additionally, the system is comprised of a mechanism for manually inputting information to the tuning mechanism so the tuning mechanism automatically provides a desired gain to the controlling mechanism based on information received from the input mechanism. Additionally, the present invention pertains to a qualitative tuning system for a processor. The present invention also pertains to a method for controlling air flow through a fume hood with a sash. The method comprises the steps of providing information concerning flow of air through the fume hood to a processor. Then, there is the step of manually inputting information concerning gain into a qualitative tuning system connected to the processor.

Abstract: An air circulation system for an RAID system, having fan motors driving fans for circulating air inside the RAID and a power supply for the fan motors, includes: a sensing circuit for producing electrical signals proportional to the environmental conditions of the RAID's interior; a controller for producing control signals for controlling the direction of rotation of the fan motors when the signal exceeds a preset reference value; and a switching circuit for changing the polarity of the power supply, and thus the direction of rotation of the fan motors, in response to control signals from the controller.

Abstract: A system for exhausting smoke from a building. The building has a roof, exterior walls and at least one room therein where smoke has accumulated. The system comprises an actuable compressor arranged to draw smokeless air from the atmosphere outside the building and force the atmospheric air through a conduit that is in communication with the compressor. The conduit permits the passage of the forced air therethrough and has a length extending across the room adjacent the ceiling of the room. The conduit has an exit end that is open to the atmosphere. The exit end projects through and extends some distance beyond the overhanging roof of the building to prevent reentry of exhausted smoke and gases. A smoke exhaust valve is located on the length of the conduit extending across the room. The smoke exhaust valve is normally in a closed position.

Abstract: A method of controlling ventilation and air quality within naturally ventilated livestock and poultry buildings comprises placing in a controller predetermined parameters of temperature and humidity for the building in question. Temperature and humidity sensors within the building are mounted above the floor with the temperature sensors being located directly above each of the animal or poultry pens. These sensors are connected to the controller to feed through the controller actual conditions of temperature and humidity within the building. The controller compares the actual conditions of temperature and humidity within the building with the predetermined parameters of temperature and humidity stored therein.

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 control system for controlling an air handling unit. The control system links the position of an exhaust air damper and a recirculation air damper so as the exhaust air damper is opened, the recirculation air damper is closed the same amount, and vice versa. An outside air damper remains completely open at all times. The relative positions of the exhaust air damper and the recirculation air damper control the amount of outside air that is emitted into the air handling unit through the outside air damper. For each of the control states of heating with minimum outside air, cooling with outside air, mechanical cooling with maximum outside air, and mechanical cooling with minimum outside air, the outside air damper remains completely open, and the position of the exhaust air damper and the recirculation air damper are controlled based on a particular state. Sequencing strategies are employed for transitions between the control states that utilize these positions of the dampers.

Abstract: A deposit cupboard (1) for solvents, combustible liquids and the like, comprises shelves (2) and at least one door. The cupboard is assigned an air intake holes (20) and an exhaust device (5), and distinguishes itself through the following combination of features: a) that the shelves (2) of the cupboard (1) are perforated and/or positioned at a distance from at least one of the adjacent inner faces of the side walls of the cupboard, in order to effect a minimum resistance against the air flow; b) that the cupboard is assigned a fire extinguishing apparatus (18) having an automatic, preferably thermostat-controlled release means; and c) that the top plate (4) of the cupboard is pivotally supported and adapted--upon the occurrence of an explosion within the cupboard--to be swung limitedly up into a securing or protecting position, wherein it forms an inclinedly directed shield, protecting the personnel from the effects of the explosion.

Abstract: A driving device which is automatically activated by detecting solar light and an automatic ventilation system utilizing the aforementioned driving device. An electric motor (21) is connected to relay switch (22), which is connected to limit switch (23) and light sensor switch (24). The limit switch (23) is connected between the relay switch (22) and the power supply and a manual main switch (25) between the light sensor switch (24) and the power supply. Normally when the main switch (25) is "on" and solar light exceeds the threshold, the light sensor detects it and the contact of the switch (24) changes to be activated. Electricity is then supplied to the relay switch (22) and the contact of the relay switch (22) also change to be activated. The electric motor is interlinked with a vent cover via the power transmission and the vent cover gradually begins to open.

Abstract: A dynamic particulate control system (12) is provided for controlling particulate levels in a room (14). The dynamic particulate control system (12) includes a supply blower assembly (22) that has a supply blower (30). The supply blower assembly (22) draws outside air and provides supply air to the room (14) at a supply flow rate dependent upon an operation speed of the supply blower (30). A first variable frequency drive (32) controls the operation speed of the supply blower (30). A return blower assembly (58) has a return blower (64). The return blower assembly (58) draws return air from the room (14) and dissipates exhaust air outside the room (14) at an exhaust flow rate dependent upon an operation speed of the return blower (64). A second variable frequency drive (66) controls the operation speed of the return blower (64). A plurality of sensors (72 through 92) periodically sample and measure system conditions and provide status signals. A controller (68) receives and processes the status signals.

Abstract: A system for providing air quality control for an indoor area divided into a plurality of zones, whereby air quality is controlled both centrally and at each of the zones, including a central controller, a central damper, a supply air stream duct, a return air duct, a plurality of zone controllers, a plurality of zone dampers, a plurality of air quality sensors (i.e., CO.sub.2, volatile organic compounds, humidity, etc. . . ) and a plurality of temperature sensors. A method for providing air quality control for an indoor area divided into a plurality of zones, whereby air quality is controlled both centrally and at each of the zones, including the steps of: reading an output value of an air quality sensor from one of the zones, comparing the output value with a zone maximum threshold value and a zone minimum threshold value, modulating the zone damper to vary a supply air flow into the zone, repeating the first three steps for each zone, determining a predetermined function (i.e.

Abstract: A ventilated enclosure comprising a substantially vertical side wall, a roof including at least one roof section, a ridge vent formed adjacent a portion of the roof section and side vent formed adjacent a portion of the substantially vertical side wall, a first elongated inflatable member disposed adjacent the ridge vent and a second elongated inflatable member disposed adjacent the side vent, the first and second elongated inflatable members each movable between a first and second position disposed in operative relationship relative to the ridge vent and side vent respectively to selectively control air flow through the ridge vent and side vent respectively and to permit air circulation through the ventilated enclosure when the first and second elongated inflatable members are each in the first position and to seal the ridge vent and side vent respectively when the first and second elongated inflatable members are each in the second position.

Abstract: A device for actuating switches in a power winch apparatus used in livestock enclosures. An actuator block is mounted on a linear rod within the frame of the power winch. When the winch is operated the movable load bearing block of the power winch engages and moves manually adjustable limits on the rod. Subsequently the actuator block mounted to the rod moves relative to a series of switches which are electrically connected to auxiliary devices as well as the power supply and drive motor of the power winch.

Abstract: An electrical interlock ties a heat recover ventilator to circulation air blower operation of an associated forced-air furnace or air conditioning system. This ensure that the blower circulates supply and return air within the building or dwelling. An interlock relay has its coil energized by the heat recovery ventilator, and a normally open contact tied to the control of a blower of the forced-air system. The furnace or air conditioner and the ventilator are operated by separate controls located within the building's comfort space. When the ventilator is operated, the circulation blower runs continuously, but thermostat actuate of the furnace or air conditioner above will not operate the ventilator.

Abstract: A method and apparatus for the mechanical ventilation and heating of a premises with improved removal of impurities from air present in the premises. At least one suction extraction device is provided for removing polluted or stale air in a region adjacent to the ceiling of the premises. Pure supply air at a temperature in the region of or exceeding the air temperature of the premises is supplied to the premises in the lower region thereof. The supply air forms a substantially horizontal and vertically narrow air jet for displacement of existing air located in a region proximate the floor. The apparatus (1) includes one low impulse device (10) and one high impulse device (20), in addition to which at least one device (31) is provided for guiding air (supply air) emitted from a fan system to the high impulse device and/or to the low impulse device.

Abstract: An air handling system is provided which includes sections for the introduction of outside or ambient air relative to a structure to be mixed with a flow of inside or return air in a flow path in which the resulting mixture is impelled by a fan to be discharged through a plurality of radially disposed vents. The temperatures of the ambient and inside air as well as of the discharge air is converted into signals which are fed into a microprocessor which in turn generates signals to control dampers which in turn controls the rates of flow of inside and outside air into the principal flow path which is controlled by the aforementioned fan which generates a constant rate of flow through the discharge air vents. The temperature of the discharge air is used to control the ratio of the flows of ambient and inside air which collectively constitute the discharge air.

Abstract: A curtain control system for controlling curtains of an animal enclosure having an electrically-operated forced air ventilation system and a plurality of adjustable drop curtains. Each of the drop curtains has an associated curtain control device for providing supplemental ventilation during power failure or excess temperatures in the enclosure. Each of the curtain control devices includes a winch for winding and unwinding a curtain control cord extending between the curtain and the winch. A winch release is moveable between a hold position for normally holding the winch handle stationary to prevent unwinding of the curtain control cord and a release position to release the winch handle and thereby release the curtains to a dropped, open position. Electromagnets hold the winch releases in the hold position during application of current and permit movement of the winch release to the release position upon interruption of electric current to the electromagnets.

Abstract: A ventilation system includes a ventilator of a simultaneous suction and exhaust type, ducts communicating the ventilator to respective air inlet and air outlet formed at one room or each of a plurality of rooms, dampers provided in the ducts respectively, and a control device responsive to signals indicative of operating conditions of items of equipment provided in the one or plurality of rooms for controlling operation of the ventilator and opening and closure of each damper in accordance with the operating conditions of the items of equipment.

Abstract: The present ventilating system is used for homes and buildings located in cold climate areas. The system includes a heat exchanger for extracting heat from the inside air discharged to the exterior and transferring said heat to the outside air admitted into the building. Blowers circulate air through the two paths of the heat exchanger and a motorized damper on the outside air path closes or opens the same. An integrated circuit and the following sensors serve to operate the system as follows: sensors detect the concentration of air contaminants, the humidity and the negative pressure of the air inside the building, while an outside air temperature sensor is also provided. When the level of air contaminants is above an adjustable preset level, the system operates in an inside air upgrading mode, namely air is circulated in both paths of the air exchanger; the same mode is used where humidity level is found to be excessive.

Abstract: Normally closed ventilating elements of a poultry building or the like are opened in response to failure of the supply of electric power to the building ventilating system by a control system which includes a source of direct current electricity arranged so as normally to energize an electromagnet and thereby to secure its armature to the electromagnet. The armature is secured to the handle of a winch which is arranged to operate the building shades. Power to the electromagnetic device is controlled through a MOSFET acting as a switch and which is controlled by a parallel combination of a capacitor and a resistor which are connected in parallel with the MOSFET gate. When power is lost, the capacitor discharges through the resistor and deenergizes the electromagnet so as to free its armature to rotate with the winch handle to open the building curtains.

Abstract: A smoke evacuation system for a building made of modular units includes sets of modular units disposed to each other and joined by a wall so as to allow a space between the modular units to define an air intake chamber. Each modular unit has a window which communicates with an air intake chamber. Each air intake chamber has an opening with an air intake fan. Each modular unit includes a chase with a window for exhausting air from the modular unit. The chases of the modular units are situated one to another so as to allow a continuous flow of air therethrough. A roof covers all of the modular units and air intake chambers, but has openings for the respective chases. Exhaust fans are mounted in said roof openings for exhausting air and smoke from said modular units. A smoke detector is installed in each chase to detect smoke in each corresponding modular unit and chase.

Abstract: An air ventilating system for use to ventilate and dehydrate and dehumidify the insulation immediately under the roof structure. The system includes an air intake member, to draw in relatively dry air, generally located above the roof surface, and a central distribution member, in the form of a plenum, disposed above or below the roof structure, and a plurality of radiating pipes that lead from the distribution plenum member, and which are located above, below or at the same level as the insulation layer under the roof structure, with such distribution pipes having a plurality of small openings therein to disperse air to the surrounding insulation layers for purposes of aerating same to remove moisture from the insulation.

Abstract: A ventilation assembly (10) for buildings (12) such as livestock barns economically and reliably prevents fan motor operation below the minimum speed required for removal of excess moisture and harmful pollutants from a ventilated building and for adequate motor cooling and lubrication. A preferred embodiment includes a fan unit (14) having a fan (18) motor (20), and a speed-responsive centrifugal switch (22), and also includes a speed control unit (16) having a temperature-responsive speed controller (24) and time delay override relay (28). In operation, the centrifugal switch (22) activates the override relay (28) if the motor (20) drops below a predetermined speed for bypassing the speed controller (24) and impose direct line voltage on motor (20) in order to increase its speed to its maximum for a predetermined time as determined by the time delay setting of the relay (28).

Abstract: A control apparatus or system for purged and pressurized electrical equipment provides rapid, controlled exchange of pressurizing or purging gas to an electrical enclosure. The control system or apparatus for NFPA Type Y and Type Z electrical equipment enclosures has a source of pressurizing gas, a rapid exchange pressure control filter/regulator, rapid exchange pressure gauge, vent control valve and a manual inlet valve providing for rapid exchange of purging gas to the electrical enclosure during start up, an enclosure control valve, enclosure pressure indicator, a venturi providing controlled leakage from the system, and a pressure loss control alarm or switch.

Abstract: A decontamination chamber entranceway to an asbestos removal work area includes rigid swinging doors for a rapid escape from the contaminated work area due to an emergency such as a fire or smoke. Also during a power failure it is easy for the workers to leave the work area through the rigid swinging doors of the invention. Each of the doors may include an air inlet opening having at least one plastic flap covering the inlet opening which allows suitable amounts of air to flow through the inlet to maintain a negative air pressure in the work area while having air flow in the work area sufficient to change the air at least every 10 to 15 minutes. The plastic flaps of the doors are preferable pivotally-mounted rigid clear plastic which seal automatically upon loss of negative air pressure in the work area. The rigid flaps can be electro-mechanically operated to positively control size and functioning of air inlet openings and close off the openings upon emergency conditions.

Abstract: A fume hood controlling apparatus that provides desirable operational safety features for persons who use the fume hoods to perform experiments or other work. The apparatus is adapted for use with fume hoods that have a filtering means lcoated between the fume hood enclosure and the exhaust duct. The apparatus determines if a filter medium is loaded beyond a predetermined amount. The apparatus also provides a visual or audible indication in response to the detected loading. The apparatus also has emergency switches near each fume hood, with the switch controlling the fume hood when actuated so that the fume hood can operate in an emergency mode, and also providing an indication to a central building console of a building supervisory and control system for heating ventilating and air conditioning apparatus.