Abstract: The invention is an airborne infection control monitoring, condition data collection, testing and reporting system. The system includes new sensors and other equipment needed to collect HVAC data, the placement of the sensors in the HVAC system, software needed to retrieve the data, and the algorithms used in analyzing the data to the required building design specifications. The proposed method and system would collect current room condition data and apply it to a virtual ventilation, room and equipment structure to efficiently determine if the building's rooms meet the air balance and infection control requirements.

Abstract: A fuel filter monitoring method includes receiving pressure signals that are indicative of a pressure drop across at least one fuel filter of a fuel supply system configured to supply fuel to at least one fuel injector of an internal combustion engine and receiving a condition signal indicative of a condition of a fuel supply system, the condition signal being generated by one or more of a geographic location sensor, an altitude sensor, and/or a fuel temperature sensor. The method includes estimating a remaining life of at least one fuel filter of the fuel supply system based on the pressure signal and the condition signal and outputting a notification indicative of the estimated remaining life.

Abstract: A filter monitoring system for a filter in a vehicle air conditioner includes a first temperature sensor to detect an air temperature of intake air drawn into an air conditioner case through the filter, a second temperature sensor to detect an evaporator temperature of the evaporator, and a processor coupled to the first and second temperature sensors and coupled to a memory. The processor is configured to calculate an actual change-rate of the evaporator temperature while a compressor is in operation, calculate an expected change-rate of the evaporator temperature based on the air temperature and operation levels of a blower and the compressor by using predetermined data with a properly functioning filter, calculate a degradation degree of the filter by comparing the actual change-rate to the expected change-rate, and output a signal indicating degradation of the filter upon determining that the degradation degree is out of an acceptable range.

Abstract: A self-calibration method of determining remaining useful life of an internal combustion engine's air filter includes establishing a pressure drop versus mass airflow rate relationship for a clean air filter using pressure drop, mass airflow rate, and temperature data captured at low and elevated engine speeds. The method also includes establishing a maximum clean air filter pressure drop at a preset maximum airflow using the clean filter relationship. The method additionally includes establishing a pressure drop versus mass airflow rate relationship for an in-service air filter using pressure drop, mass airflow rate, and temperature data captured at low and elevated engine speeds. The method also includes determining a maximum in-service air filter pressure drop at the preset maximum airflow using the in-service filter relationship. The method further includes comparing the maximum clean and in-service air filter pressure drops to determine the remaining useful life of the in-service air filter.

Abstract: The techniques described herein may provide for more efficient power management of equipment based on weather conditions. For instance, weather measurements (e.g., or weather forecasts based on weather measurements) may be used to determine whether or not to initiate a power disconnect procedure. When some weather condition (e.g., wind, temperature, rain, humidity, etc.) exceeds a threshold, a power disconnect procedure may be initiated such that a power source of certain equipment may be disconnected from a power distribution system. In some examples, an environmental monitor may send environmental measurements or conditions to a programmable processor. In instances where the programmable processor determines that some environmental threshold or condition has been met, the programmable processor may send a disconnect signal (e.g., a disconnect power signal) to a power disconnect device. The power disconnect device may thus disconnect the power distribution system from the power source.

Abstract: In an example, an air filter system includes an air filter and a thermally conductive particulate sensor (TCPS). The TCPS includes a temperature sensor to measure a first temperature of the TCPS at a first time, measure a second temperature of the TCPS at a second time, and provide the measured first temperature and the measured second temperature to a controller. The controller to determine an actual rate of temperature change based on the measured first temperature and the measured second temperature, compare the actual rate of temperature change to a target rate of temperature change, and provide a notification when a difference between the actual rate of temperature change and the target rate of temperature change is greater than an accumulation threshold indicative of a threshold amount of particulate accumulation on the TCPS.

Abstract: A smoke evacuation device that evacuates smoke from a surgical site and filters the smoke from the air. The smoke evacuation device can include a fluid trap for removing moisture from the smoke. The smoke evacuation device can also include a filter with a compression mechanism for compressing a filter medium. The smoke evacuation device can also include features for controlling flow parameters, noise, and vibrations of the device. A remote activation device can also be used to activate the smoke evacuation device upon detection of certain system parameters.

Abstract: The present utility model discloses an air-purifying apparatus. The air-purifying apparatus comprises a filter screen, filter screen type determining component, and filter screen service life determining component. The filter screen is for filtering particles and at least one of specific chemical matters in the air. The filter screen determining component is configured to determine a type of the filter screen. The filter screen service life determining component is configured to determine whether the filter screen needs to be changed according to the determined type of the filter screen and a use condition of the filter screen. With the air-purifying device of the present disclosure, remaining service lives of the filter screens of different types or specifications may be obtained, then a user may be prompted when the filter screen needs to be changed, thereby allowing the user to maintain a good air-purifying effect at any time.

Abstract: An aspiration smoke detection system for detecting the presence of a fire within a region of interest. The aspiration smoke detection system includes a smoke detection unit for detecting the presence of smoke particles suspended in air; and one or more local sensors located remotely from the smoke detection unit for measuring a property of air from the region of interest that is drawn into the aspiration smoke detection system. An inlet piece includes a sensor for use with the aspiration smoke detection system is also provided. A method of detecting a fire using the aspiration smoke detection system and a method of locating a fire using the aspiration smoke detection system are also provided.

Abstract: A return pan for an agricultural harvester has an inclined upper surface portion, disposed to receive grain from a threshing or separating mechanism and laterally convey grain under the force of gravity to an inlet of a grain flow sensor.

Abstract: A filter assembly for a fluid flow system includes a filter housing, a housing inlet to allow the fluid flow into the filter housing and a housing outlet to allow the fluid flow to exit the filter housing. A filter element is located in the filter housing to collect contaminants from the fluid flow. A pressure sensor is located to measure a pressure drop across the filter element. The pressure sensor includes at least one sense line extending into an interior volume of the filter housing. A method of monitoring a filter assembly for a fluid flow system includes positioning a pressure sensor at a filter assembly, extending at least one sense line from the pressure sensor into an internal volume of a filter housing of the filter assembly, and measuring a pressure drop across a filter element of the filter assembly via the pressure sensor.

Abstract: An air conditioner includes a purifying unit having at least one filter; a sensor unit including an air quality sensor; and a controller configured to: calculate a filter contamination level based on (i) data regarding indoor air quality measured by the air quality sensor during an operation of the air conditioner, and (ii) an operating time of the air conditioner; combine the calculated filter contamination level with a pre-stored filter contamination level to obtain a combined filter contamination level; and based on the combined filter contamination level satisfying at least one filter replacement condition, output filter replacement indicator information.

Abstract: The invention refers to a pressure-measuring device for converting a mechanical or hydraulic pressurization in a measuring signal and for forwarding the measuring signal to a remote evaluation unit.

Abstract: A method for controlling air volume of an electric device to be constant, the device being adapted to exhaust or supply air, the method including: A) establishing M constant air volume control functions Qi=F(n) corresponding to M air volume points CFMi in the microprocessor of the system controller; B) allowing the microprocessor to receive or preset a target air volume IN-CFM; C) starting the motor, when the motor operates in a stable state, comparing M air volume points CFMi with the target air volume IN-CFM, and ensuring that the target air volume IN-CFM falls within two known air volume points CFMi and CFMi?1; D) using the two known air volume points CFMi and CFMi?1 to calculate a constant air volume control function Q0=F(n) corresponding to the target air volume IN-CFM by interpolation method; and E) controlling a motor parameter Q0 and a rotational speed n.

Abstract: A method for determining a degree of loading on a filter medium of a filter device on a vehicle through which a fluid flows includes determining an operating characteristic of the filter device based on at least one operating quantity of the vehicle and comparing a predefined reference characteristic of the filter device with the operating characteristic. The degree of loading is derived from a result of the comparing step.

Abstract: A monitoring system for apparatus and systems in commercial and residential properties is provided. The monitoring system consists of a head unit and a tail unit, each of which has one or more sensors that measure performance parameters that are important to understanding the performance of the apparatus and system being monitored. As an example, an HVAC system may be monitored to determine when an air filter needs to be changed, or to predict when failure of the HVAC system may be imminent. The sensor array in the head unit and tail unit measure performance and report alerts and historical system performance to users through a mobile app, social media accounts, or any other system for communicating over a wired or wireless network connection.

Abstract: The present application relates to an apparatus for purifying and/or humidifying air, and a related method for purifying and/or humidifying air. The apparatus comprises a rotary filter (1), a fan (9, 10) for passing air through the rotary filter (1), and a reservoir (4, 5), and wherein the rotation speed of the rotary filter (1) and the settings of the fan (9, 10) depend on the ambient relative humidity and ambient gas pollutant concentration. The apparatus combines the feature of chemisorption with the use of a rotary filter (1), thereby providing an apparatus which is able to purify air and/or regulate the ambient humidity based on humidity levels and levels of a target gas pollutant in the air. The invention removes the need for a pump for liquid transport, removes the need for frequent and expensive filter changes by the user, and instead only requires the user to periodically refresh the filtration solution in the reservoir (4, 5).

Abstract: The present disclosure is a filtration monitoring system. Filtration monitoring system may include a sensor configured to measure a characteristic of usage of a monitored filter. The sensor may be communicatively coupled to a controller which is configured to transfer measured data to a server of the filter monitoring system. Server may be configured to store historical data regarding representative filter usage and may determine a predicted expiration time for a monitored filter which may be adjusted based upon the measured data from the sensor.

Abstract: An exhaust gas purification device, including a diesel particulate filter (“DPF”) for collecting particulate matter contained in an exhaust gas, a forced regeneration unit or performing forced regeneration, a capacitance detection unit for detecting a capacitance of the DPF, a total accumulated amount estimation unit for estimating a total amount of accumulated particulate matter and ash collected in the DPF on the basis of the detected capacitance, and an ash accumulated amount calculation unit for calculating an amount of accumulated ash by using, as the amount of accumulated ash, the total amount of accumulation which is estimated when the forced regeneration finishes.

Abstract: A filter condition indicator system is described herein. A pressure differential switch monitors air pressure across a filter, and a transmitter coupled to the pressure differential switch sends a signal to a networked device. If the pressure differential near the filter triggers the switch, then a “dirty” signal is sent to or retrieved by a mobile device which indicates that the filter is dirty and should be replaced. The filter condition indicator is able to be used by bypassing a thermostat and sending an alert to a computer or mobile device wirelessly. Alternatively, the filter condition indicator system described herein is able to be used in conjunction with a previously installed furnace/thermostat system by utilizing the pre-existing thermostat wiring. The filter condition indicator system is able to be used with HVAC systems, air conditioning systems, other heating/cooling systems, or other systems or devices.

Abstract: There is described a filter arrangement for a particle detector for detecting particles in an environment. The particle detector can include one or more sensors for analyzing fluid in a detection region to produce sensor output. The filter arrangement includes structure defining flow paths, for conveying fluid from the environment towards the detection region, including a first flow path, which includes a filter, and a second flow path bypassing the filter. There is also provided a mechanism for controlling relative flow rates of fluid through the first flow path and the second flow path and a controller configured to receive the sensor output corresponding to at least two relative flow rates and apply logic thereto to generate an output indicative of a condition of the filter.

Abstract: An outdoor unit of an air conditioner includes: an outdoor fan; an outdoor air temperature detector; and a controller, wherein the controller performs: a fan defrost operation to circulate the refrigerant in the same order as in the case of a cooling operation and rotate the outdoor fan when the outdoor air temperature is within a predetermined temperature range, a fan defrost operation over a period of a first fan defrost operation time when the outdoor air temperature is lower than a first predetermined temperature, and a fan defrost operation over a period of a second fan defrost operation time that is longer than the first fan defrost operation time when the outdoor air temperature is equal to or higher than a second predetermined temperature that is higher than the first predetermined temperature.

Abstract: A method for estimating energy use in an air filtration system using a preselected air filter includes the steps of: entering filtration system information into a computer having access to dust holding capacity—pressure drop curves for a plurality of air filters; determining an estimated current energy use of the air filtration system for a current air filter in the system; and presenting the estimated energy use on a display of the computer. Proposed filters can be evaluated and filter operation and changing cycle can be optimized.

Abstract: An agricultural harvesting system including a chassis, an agricultural product moving device coupled to the chassis, an airflow system, a cleaning system and an airflow characterizing system. The cleaning system is configured to receive the agricultural product from the moving device. The cleaning system is configured to receive an airflow from the airflow system. The airflow characterizing system is at least partially positioned in the airflow, and is configured to measure an airflow profile across the cleaning system. The airflow characterizing system includes a plurality of sensors that determine airflow by measuring a thermal transfer from the sensors to the airflow. The airflow characterizing system being configured to maintain a substantially constant electrical resistance of the sensors as the airflow varies. The airflow characteristics are measured in the cleaning system and are used to improve the cleaning capacity of the harvesting system.

Abstract: Systems for delivery of therapeutic agents and related methods are disclosed. A sensing system is configured to detect a chemical in the vicinity of a patient and transmit a signal to a controller upon detection. A controller is configured to release a therapeutic agent which is transported to the site of interest. The controller communicates with an electronic medical records database, an alarm and a nurse call system.

Abstract: A filter assembly has a qualified filter element that filters fuel, a filter housing for the qualified filter element and a water-in-fuel sensor that senses presence of water in the filter housing. An electrical resistance of the water-in-fuel sensor changes based upon whether the qualified filter element is installed in the housing. A filter assembly can also have a plurality of magnetic elements disposed on at least one of the filter housing and the qualified filter element. A plurality of wires are disposed on at least the other of the filter housing and the qualified filter element. The control circuit determines that the qualified filter element is installed in the filter housing based on a change in the electrical current in the plurality of wires.

Abstract: A method of determining a condition of a filter located within a system is provided. The method may include determining a first air flow measurement value for a first air flow through the filter, determining a first energy consumption value associated with generating the first air flow through the filter, determining a first ratio between the first air flow measurement value and the first energy consumption value, determining a second air flow measurement value for a second air flow through the filter, determining a second energy consumption value associated with generating the second air flow through the filter, and determining a second ratio between the second air flow measurement value and the second energy consumption value. The filter may then be replaced based on a comparison between the determined first and the determined second ratio.

Abstract: A filter life sensor assembly within an air handling system is disclosed. The air handling system includes an air flow intake, an air flow exit, and a filter disposed between the air flow intake and air flow exit. The filter sensor assembly comprises a bypass connecting the air flow intake to the air flow exit, a dielectric sensor adjacent the bypass, wherein the dielectric sensor generates an electrical signal in response the air flow passing through the bypass.

Abstract: A mechanical fluid meter, for liquid or gas, includes an electronic device (E) that has means for metering, and generally also displaying, consumption, said fluid meter including: at least one fluid temperature sensor (3) near the meter and at least one ambient temperature sensor (4) where the meter is installed; a connection means between the temperature sensors (3, 4) and the electronic device (E); and analysis means (5) for establishing the temperature difference (??) between the fluid temperature and the ambient temperature and for taking into account the fluid flow rate value supplied by the meter, said analysis means being programmed so as to display and/or transmit information indicating a meter blockage when the temperature difference (??) is higher than a predetermined limit and the flow rate value supplied by the meter is zero.

Abstract: A method for fire detection in enclosed environments (1) subject to explosion protection regulations out of which an air-dust mixture is filtered while the concentration of dust of the air-dust mixture is lowered to under the explosion limit by a filter (2) and the aspirated air-dust mixture is checked for burning characteristics and if appropriate a fire alarm is triggered, in which the function of the filter (2) is monitored, the fire detection is carried out by use of an aspirating smoke detector system (7) not approved for use in potentially explosive areas but instead is deployed outside the ex-zone and if the filter (2) is destroyed a signal processing unit (15, 15.1) of a malfunction monitoring sensor (14) generates a signal which initiates a subsequent action preventing aspirated air-dust mixture with an elevated concentration of dust from entering the aspirating smoke detector system (7).

Abstract: Methods and systems for indicating a status of an air filter of an HVAC system may include receiving a measure that is related to an amount of flow restriction presented by the air filter in an HVAC system, using the measure to determine whether the air filter does not need replacing, the air filter needs to be replaced soon, or the air filter should be replaced now, and displaying on a display of an HVAC controller an air filter status indicator, wherein the air filter status indicator includes a stop-light metaphor. In one example, the air filter status indicator may display a green color when the air filter does not need replacing, display a yellow color when the air filter needs to be replaced soon, and display a red color when the air filter should be replaced now. In some cases, the air filter status indicator may also include a qualitative term indicative of the current status of the air filter.

Abstract: An improved pump, reservoir and reservoir piston are provided for controlled delivery of fluids. A motor is operably coupled to a drive member, such as a drive screw, which is adapted to advance a plunger slide in response to operation of the motor. The plunger slide is removably coupled to the piston. A method, system, and an article of manufacture for automatically detecting an occlusion in a medication infusion pump is provided. The electrical current to an infusion pump is measured. Based on a series of measurements of one or more variables, the infusion pump detects whether there is an occlusion in the system.

Abstract: The invention hereby disclosed is a vertical filtering and separating suction machine of chips, steam and smoke for machining center, lathe machine or other machines, which operates by sudden changes of sucked air, thus generating hits which separate heavy particles, whose suction pipe extends almost up to the bottom of the rotor, which only uses filters at the end of the process of air purification, whose rotor has outer paddles modified in order to improve suction power and to cause more hits of air flow, and which includes an air pressure alarm showing the filter is saturated.

Abstract: Automatic devices that determine when pollutant deposits have accumulated in ductwork may be employed to notify maintenance personnel or automated cleaning equipment of the need for ducts to cleaned or replaced. Various detection devices may be employed to detect a property of accumulated grease and generate an indication of an accumulation. The detection device may present a surface to the fume stream inside a duct. The surface may be cooled to a temperature that represents a worst case temperature so that the accumulation due to condensation on the detector surface is at least as high as the coolest surface in the ductwork which is being monitored. Alternatively, the detection device may be located external to the duct. The detection device may interrogate the surface of the duct through contact or noncontact measurements to determine the thickness of an accumulated grease layer on the interior of the duct.

Abstract: The invention provides an electronic apparatus including a casing, a thermal sensor, a controlling unit, an air filter and a cooling fan. The air filter is detachably attached to the inlet of the casing. When the air filter is attached to the inlet of the casing, a partial structure of the air filter neighboring the thermal sensor blocks an airflow from flowing through the thermal sensor. In particular, when the air filter is attached to the inlet of the casing, or when the air filter is not attached to the inlet of the casing, the controlling unit always calculates a determined speed by applying the temperature sensed by the thermal sensor in a function of speed versus temperature, and controls the cooling fan operating under the determined speed to cool the electronic apparatus.

Abstract: Methods and systems for indicating a status of an air filter of an HVAC system may include receiving a measure that is related to an amount of flow restriction presented by the air filter in an HVAC system, using the measure to determine whether the air filter does not need replacing, the air filter needs to be replaced soon, or the air filter should be replaced now, and displaying on a display of an HVAC controller an air filter status indicator, wherein the air filter status indicator includes a stop-light metaphor. In one example, the air filter status indicator may display a green color when the air filter does not need replacing, display a yellow color when the air filter needs to be replaced soon, and display a red color when the air filter should be replaced now. In some cases, the air filter status indicator may also include a qualitative term indicative of the current status of the air filter.

Abstract: An autonomous filter device and a method for improving the filter life and performance is disclosed. The filter element is equipped with one or more sensors, adapted to measure one or more characteristics. In response to the measured characteristic, the control logic within the filter element is able to determine an appropriate response. For example, the control logic may determine that a sudden, but temporary, blockage has occurred in the filter membrane. In response, the control logic may initiate a specific response designed to alleviate the blockage. The control logic will then determine the success of the response, based monitoring any change in the fluid characteristics. Based thereon, the control logic may alert the operator that the filter element must be replaced. Alternatively, if the response was successful in correcting the blockage, the control logic need not notify the operator, as the filter element is back to normal operating operation.

Abstract: A projection display device includes: a dustproof filter that removes dust and a foreign material from drawn air; an air guide path that guides, to a liquid crystal panel, the cooling air blown by a suction fan; an air velocity detector that is arranged in the air guide path and detects the velocity of the cooling air that flows in the air guide path; and a CPU that determines, on the basis of the value detected by the air velocity detector, whether or not the dustproof filter is clogged. The air velocity detector detects the velocity of the cooling air by measuring the temperature of the air in the vicinity of the heat generating element that will be increased due to heat transfer generated by the heat generating element. This configuration improves accuracy in determining whether or not the dustproof filter is clogged.

Abstract: The present invention relates to a system for determining particle transmittance Tx of a filter for use with a particle detection system to provide a filter warning for aspirated particle detection systems by detecting a level of first particles having a size indicative of smoke particles and which pass through the detection system; determining an integrated smoke hours value by integrating the detected level of first particles over time; estimating the smoke particle transmittance Tx of the filter by applying a predetermined weighting operation to the integrated smoke hours value. An empirical measure of a filter's particle transmittance Tx, due to at least first particles having a size indicative of smoke particles may be achieved by way of integrating a level of such first particles passing through a particle detection system over time to determine the proportion of smoke particles arrested by a filter, “integrated smoke hours”.

Abstract: A vibratory flow meter (100) for correcting for entrained gas in a flow material is provided. The vibratory flow meter (100) comprises a flow meter assembly (10) configured to generate a vibrational response for the flow material, a bubble size sensor (50) configured to generate a bubble measurement signal for the flow material, and meter electronics (20) coupled to the flow meter assembly (10) and to the bubble size sensor (50). The meter electronics (20) is configured to receive the vibrational response and the bubble measurement signal, determine a bubble size of bubbles in the flow material using at least the bubble measurement signal, determine one or more flow characteristics of the flow material using at least the vibrational response and the bubble size.

Abstract: The present invention provides a method for adjusting a center frequency of a filter utilized for extracting information carried via a target channel. The method includes: detecting adjacent channel interference (ACI) for the target channel to generate a channel interference information; and adjusting the center frequency of the filter for the target channel according to the channel interference information.

Abstract: The present invention describes a system for accurately measuring the concentration of a substance within a filter housing. A concentration sensor and a communications device are coupled so as to measure and transmit the concentration of a particular substance within the filter housing while in use. This system allows the operator to certify the integrity of the filters within the filter housing at the customer site without additional equipment. In one embodiment, a tracer gas, such as helium or hydrogen, is added to a carrier and injected into the system. The concentration of tracer gas at a specific operating transmembrane pressure is indicative of bubble pointing specific pores in the filter. This test will give a more sensitive indication of the bubble point and the presence of defects than a standard diffusion test. In a second embodiment, two gasses, in a known ratio, are introduced into the filter housing.

Abstract: Disclosed is a drain blockage responsive alarm system. The drain blockage responsive alarm system comprises a cleanout cap member, at least one drain blockage responsive element, and an alarming module. The cleanout cap member is capable of being installed at a portion of a drain pipe. Further, the at least one drain blockage responsive element is configured to the cleanout cap member adapted to sense clog deposition at the portion of the drain pipe, and to generate an output signal upon sensing the clog deposition. Furthermore, the alarming module is electrically coupled to the at least one drain blockage responsive element for generating an alarm signal upon receiving the output signal.

Abstract: A flow indicator for showing blocking of filter cotton, being installed in a pipe line of a spraying head for the purpose of showing and controlling blocking of filter cotton in a filter in connecting with a submerged pump for the spraying head, it has a tri-branch tube to connect the pipe line, and to connect to a housing provided therein with an electric power source, an indicating device, an igniting switch and a triggering device, the tri-branch tube is provided therein with a pusher rod that can detect the pressure of water and can thus be moved. When the filter cotton is blocked to lower the water pressure, the pusher rod is moved and makes the triggering device to turn on the indicating lamp device, in order to warn a user to clean or change the filter cotton of the filter.

Abstract: An oil leakage detector for detecting the leakage of e.g. diesel or fuel oil in an engine room of a vessel comprises a conduit for an airflow therethrough, and a screen in the conduit. The screen is meshed to prevent oil particles or droplets from passing therethrough. A sensor determines a pressure loss across the screen, and a control system operatively connected to the sensor is configured to output an oil leakage warning signal if the pressure loss exceeds a predetermined threshold value. A fan may be provided for generating the airflow through the conduit. A gas sensor for determining the presence of hydrocarbon, carbon monoxide or carbon dioxide is optionally provided.

Abstract: An apparatus includes a mounting base and a compatible electrical unit removably carried on the base. The base carries a transducer and a sensor external to the unit. The transducer emits radiant energy toward the unit. The sensor receives radiant energy modulated by the unit. A local control unit can store the received, modulated radiant energy as a base-line profile. Subsequently, additional profiles can be generated and compared to the stored base-line to determine is a spatial characteristic of the electrical unit has changed.

Abstract: The present invention relates to a system for determining particle transmittance Tx of a filter for use with a particle detection system to provide a filter warning for aspirated particle detection systems by detecting a level of first particles having a size indicative of smoke particles and which pass through the detection system; determining an integrated smoke hours value by integrating the detected level of first particles over time; estimating the smoke particle transmittance Tx of the filter by applying a predetermined weighting operation to the integrated smoke hours value. An empirical measure of a filter's particle transmittance Tx, due to at least first particles having a size indicative of smoke particles may be achieved by way of integrating a level of such first particles passing through a particle detection system over time to determine the proportion of smoke particles arrested by a filter, “integrated smoke hours”.

Abstract: A thermal management system includes an airflow sensor that measures airflow in an air path inside an enclosure to be cooled, wherein the air path includes a filter and a fan. A controller is responsive to the airflow sensor for monitoring the rate of airflow inside the enclosure and determining the condition of the filter. In one embodiment, the airflow sensor is an active type sensor, such as a thermistor, disposed on circuit boards. In further embodiments, the airflow sensor is disposed proximate a tube through the filter.

Abstract: An air filter monitoring system for indicating when to clean or replace a flexible air filter includes an air filter having a peripheral frame and an interior filtering region, a fixed support structure for receiving the air filter and maintaining the perimeter of the filter frame in a generally fixed position while allowing the interior filtering region to flex in response to air flow through the filter, and a filter change indicator having a predetermined bias force. The filter change indicator is arranged to contact the interior filtering region of the filter, wherein when the predetermined bias force is reached, the filter change indicator is activated to notify a user to clean or replace the filter.

Abstract: Static pressures are measured in an HVAC system and utilized to predict the condition of a filter in the HVAC system. As the filter becomes clogged, the static pressure can be expected to increase. Changes in the static pressure are determined periodically, and utilized to predict the condition of the filter. A display provides a user with an indication of the current condition of the filter, and a recommendation to replace the filter once it reaches a predetermined condition.