Abstract: A method is provided for operating a suction device that includes a suction unit and a removable filtering device. The suction unit generates a suction flow that flows through the filtering device when arranged on the suction device, in which, after the suction unit is started up, a check is performed of whether the filtering device is present, and if detected as not present, the suction unit is switched off. An evaluation unit uses check data to determine whether a switch-off signal is to be generated for the suction unit. The evaluation unit uses an algorithm or a table to arrive at a decision on switching off the suction unit based on the check data. The table contains at least one threshold value or the algorithm defines at least one threshold value, wherein the at least one threshold value is a threshold value for switching off the suction unit.

Abstract: A hand vacuum cleaner has an information display device provided on a rear wall of the rear end of the hand vacuum cleaner.

Abstract: A system and method of compensating for airspeed when measuring pressure drop across a filter system on an aircraft may include a pressure compensator, an internal pressure sensor, and an external pressure sensor. A filter media may be located around a housing such that air flows through the filter media into a clean air space defined by the filter media and the housing. The pressure compensator may be located outside of the clean air space and within an airstream of the aircraft. The internal pressure sensor may be configured to measure an internal pressure that varies with airspeed and the external pressure sensor may be located on the pressure compensator to measure an external pressure. The external pressure sensor may be positioned such that the external pressure varies according to a known relationship relative to the internal pressure as the airspeed of the aircraft changes.

Abstract: A system for collecting property status information from a property for a virtual appraisal receives the property status information from a plurality of devices positioned about the property, stores the property status information in a database, and assesses the property status information to create the virtual appraisal for the property.

Abstract: A breathing light assembly of an air purifier includes a front panel, a cover, a breathing light, a body cover, and a reflective strip. The cover includes a light transmission panel and a curved surface and is mounted to the front panel. The breathing light is mounted to the curved surface and faces the light transmission panel. The body cover cooperatively defines an optical channel with the cover. A surface of the body cover includes a light emitting zone within the optical channel. The light emitting zone faces the breathing light across the optical channel. Light emitted by the breathing light passes through the light transmission panel to the light emitting zone. The reflective strip is mounted on the light emitting zone and positioned at an end of the optical channel. The reflective strip reflects the light emitted by the breathing light.

Abstract: Certain embodiments herein relate to systems and methods for managing turbine intake filters. In one embodiment, a system can include at least one memory configured to store computer-executable instructions and at least one controller configured to access the at least one memory and execute the computer-executable instructions. The instructions may be configured to monitor an indication associated with air flow through at least one filter of a turbine intake system. The instructions may be further configured to facilitate in the execution of at least management task of the turbine intake system, based at least in part on the indication of air flow through the filter.

Abstract: Improvements in a filter where the filter self-expands based upon increased pressure or vacuum in the filtering stream. The expandable filter is adaptable to filtering a wide variety of media including air used in HVAC units, gases that are used to filter impurities out of gases and for industrial applications. The expandable filter to maintain a constant pressure or vacuum in the plenum or filter. The filter self-expands as the pressure or vacuum increases and pushes, pulls or draws the filter into an elongated or heightened configuration. As the filter expands new filter material is exposed that was not previously exposed for filtering. Expansion doubles, triples, or further increases the filter collection surface area. The filter does not rely upon gravity and expands based upon the increase of pressure or vacuum in the plenum the filter can be arranged in a vertical or horizontal orientation.

Abstract: Apparatus for transforming the air exchange load of a higher air exchange rate space into the air exchange load of a lower air exchange rate space, including: a housing; an air inlet and at least one air outlet formed in the housing; a passageway extending through the housing and connecting the air inlet to the at least one air outlet; a circulation fan disposed in the passageway so as to draw the air of the higher air exchange rate space into the air inlet, through the passageway, and return that air to the higher air exchange rate space through the at least one air outlet; and a filter disposed in the passageway for purging noxious substances from the air passing through the passageway, whereby to transform the air exchange load of a higher air exchange rate space into the air exchange load of a lower air exchange rate space.

Abstract: In embodiments, an air filter apparatus includes a base structure (210), an air propulsion mechanism (220), and an adhesive air filter (ADAF) (240) that has an adhesive surface (242). The air propulsion mechanism may establish an air flow (252, 254, 256, 258). The base structure may be configured such that the air flow goes past a vicinity (222) of the adhesive air filter (240), and at least some of the particulates (262, 264) in the flowing air impact the adhesive surface (242), and thus become adhered to it and captured by it. The adhesive air filter could be made from commercially available adhesive tape that is discarded when saturated. Since it is impervious to air, small particulates can be captured upon impact economically. Embodiments may purify the air in enclosed spaces such as homes, offices, and passenger compartments, preventing health problems. Embodiments may further reduce pollution from chimneys.

Abstract: A filter sensor to monitor an air filter in an air conditioning system is disclosed. The filter sensor includes a housing having an interior passage. The housing is located in relation to an air vent of the air conditioning system. A propeller is mounted in the interior passage. The propeller is rotated by the filtered air flow of the air conditioning system. A motion sensor is provided in proximity to the propeller or its shaft. A controller is coupled to the motion sensor to determine the rotational speed of the propeller and correlate the rotational speed of the propeller with the condition of the filter. An indicator is coupled to the controller to indicate a status of the air filter.

Abstract: Apparatus for transforming the air exchange load of a higher air exchange rate space into the air exchange load of a lower air exchange rate space, said apparatus comprising: a housing for mounting to a surface of the higher air exchange rate space; an air inlet formed in said housing; at least one air outlet formed in said housing; a passageway extending through said housing and connecting said air inlet to said at least one air outlet; a circulation fan disposed in said passageway so as to draw the air of the higher air exchange rate space into said air inlet, through said passageway, and return that air to the higher air exchange rate space through said at least one air outlet; and a filter disposed in said passageway for purging noxious substances from the air passing through said passageway, whereby to transform the air exchange load of a higher air exchange rate space into the air exchange load of a lower air exchange rate space.

Abstract: A filter system includes a housing, a filter medium disposed within the housing and a optical analyte sensor also disposed within the housing in fluid communication with the filter medium. The optical analyte sensor includes a detection medium that changes at least one of its optical characteristics in response to an analyte. The filter system further includes an optical reader having at least one light source and at least one detector. The optical reader is attached to the housing such that at least a portion of light emitted by at least one light source is reflected from the optical analyte sensor and captured by at least one detector.

Abstract: Disclosed herein is a ceiling embedded type air conditioner having a filter cleaning device to clean a filter. The filter cleaning device includes a cleaning unit to remove dust from the filter and a dust storage unit to store the dust removed by the cleaning unit. The filter may automatically and periodically be cleaned by the cleaning unit and the removed dust may be stored in the dust storage unit, which eliminates a need to separate and clean the filter.

Abstract: A filter sensor to monitor an air filter in an air conditioning system is disclosed. The filter sensor includes a housing having an interior passage. The housing is located in relation to an air vent of the air conditioning system. A propeller is mounted in the interior passage. The propeller is rotated by the filtered air flow of the air conditioning system. A motion sensor is provided in proximity to the propeller or its shaft. A controller is coupled to the motion sensor to determine the rotational speed of the propeller and correlate the rotational speed of the propeller with the condition of the filter. An indicator is coupled to the controller to indicate a status of the air filter.

Abstract: A gas pressure monitor system for a pneumatically-powered surgical machine includes a first transducer, a second transducer, and a controller. The first transducer is located upstream from a filter and is configured to read a first pressure of a gas before the gas enters the filter. The second transducer is located downstream from the filter and is configured to read a second pressure of a gas after the gas exits the filter. The controller is configured to compute a difference between the first pressure and the second pressure. A state of the filter is determined from the difference between the first pressure and the second pressure.

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: Disclosed is an indoor unit having a dust storage container in which dust removed from an air filter is stored, and a dust collecting box into which the dust in the dust storage container is transferred by utilizing an effect of blown air. The dust storage container is provided with a full condition detection means for detecting a dust full condition of the dust collecting box. The full condition detection means includes an LED and a phototransistor which are opposed to each other with a storage portion interposed therebetween. After a dust transfer operation which transfers the dust from the dust storage container to the dust collecting box, an intensity of light of the LED that has passed through the storage portion is detected by the phototransistor. If the detected light intensity is equal to or less than a set value, a full condition of the dust collecting box is detected.

Abstract: A filter system includes a housing, a filter medium disposed within the housing, an optical analyte sensor, and an optical reader. The optical analyte sensor is characterized by a first region that exhibit a first response to an analyte of interest and a second region that exhibit a second, different, response to an analyte of interest. The optical analyte sensor includes a detection medium and is disposed within the housing such that the detection medium is in fluid communication with the filter medium. The optical reader includes at least one light source and at least one detector.

Abstract: The invention relates to a fan-and-filter unit to be mounted in the wall off a switch cabinet or housing, comprising a fan unit inserted in a fan housing, a filter mat arrangement mounted upstream of the fan unit and a fan cover immobilizing the filter mat. An embodiment advantageous for operation of the fan-and-filter unit consists in that the fan-and-filter unit has a filter mat monitoring unit which is designed to detect the service life and/or a degree of soiling of the filter mat arrangement and which comprises an insert integrated into the fan housing or the fan cover and having an illuminated display visible from the exterior of the fan cover facing away from the fan unit and being designed to display at least exceeding of a predetermined or predeterminable service life and/or a predetermined or predeterminable degree of soiling.

Abstract: An indicator for a refrigerator filter which has a body configured to contain a replaceable filter cartridge and including an openable cap to enclose the filter cartridge within the body. The indicator includes a control having a filter life determination mechanism and arranged to emit a signal when a life of the filter cartridge is determined to be expired. A visual display is arranged in association with the body which comprises an illuminating component which illuminates upon receipt of the signal from the control, graphics positioned in association with the body, and a light pipe extending from the graphics towards the illuminating component to transmit light from the illuminating component to the graphics.

Abstract: A self-alarming air cleaner is disclosed. The air cleaner includes an air filter element (1), a light emitting element (2) and a light sensor (3). The light emitting element (2) and the light sensor (3) are both faced to the air filter element (1). The light emitted from the light emitting element (2) is reflected by the air filter element (1) or permeated to the air filter element (1), then forms an area of light attenuation where the light sensor (3) is located. The light emitting element (2) and the light sensor (3) connect with a circuit which has an alarming device. When much dust is accumulated on the air filter element (1), the intensity of the light reaching the light sensor (3) is weakened and the alarming device (4) can give an alarm automatically.

Abstract: A system recognizes a check-up time of a filter of an air cleaner. The system includes a power unit that supplies power to the system, a pressure sensor that measure pressure of a filter, at an outlet connected with a filter unit, a conversion circuit that converts the measured value into a predetermined type, a processor that controls the measurement period of the pressure sensor and receives and compare the measured value converted by the conversion circuit with a predetermined reference value, and a display unit that displays a filter replacement period.

Abstract: A respirator leak detection system and method for increasing the sensitivity and accuracy of leak detection through the fit seal of a respirator. A charged particle separator is used to separate charged particles that pass therethrough and to draw charged particles away from an aerosol flow into a clean gas flow. The separator may also be configured as an aerosol concentrator that takes in a major aerosol flow and outputs a minor flow of higher particle concentration. Neutral particles having no charge, which may have passed through the filtering medium respirator and which are not indicative of fit seal leaks are not entrained in the output flow for subsequent detection, thus increasing the accuracy of the filter leak detection system.

Abstract: A connecting tube having a dust sensing function is provided. The connecting tube includes a tube element having a first air flowing passage; a body having a second air flowing passage to communicate with the first air flowing passage; a detecting sensor disposed on the second air flowing passage to detect whether the dust or dirt passes through the second air flowing passage; a lamp part to operate according to a signal outputted from the detecting sensor; a rotating part rotatably disposed on the body; a rotation driving-passage part disposed on the body to draw in an external air into the second air flowing passage and thus to rotate the rotating part; an electric generator connected to the rotating part to generate an electric power; and a muffler part to reduce noises from the rotating part and the flowing air.

Abstract: A heating, ventilating and air conditioning (HVAC) return air system actuator device which could, among other things, be employed to notify a user of a clogged air filter and/or disperse a fragrance into a forced air HVAC system is disclosed. In one embodiment the actuator device has a movable actuator mounted within a housing. The movable actuator moves in response to a user pre-set pressure differential. When the pre-set pressure differential is reached, the movable actuator impacts a lever which activates a switch. The switch could be connected to a host of items such as a light emitting device to notify the user to a clogged air filter condition and/or to activate a pump to release a fragrance into the HVAC system.

Abstract: An air filter with a clog-detecting device includes a housing having a wind outlet and a wind intake, a filter unit positioned between the wind outlet and the wind intake, an exhauster disposed between the wind outlet and the filter unit, a magnetic induction unit positioned on the exhauster, and a warning unit assembled on the housing and electrically connected with the magnetic induction unit. A metallic plate is axially fixed on the rotating spindle of a motor and positioned adjacent to the magnetic induction unit, having its upper side formed with at least one projection to enable the magnetic induction unit to induce the metallic plate and produce pulse signals. Thus, by detecting the frequency of the pulse signal, a user can know whether the air filter is clogged or not and proceed to remove the clogged condition to let the air filter continue to work normally.

Abstract: A computing device having a cooling fan, a heat exchanger, and a filter disposed between the heat exchanger and the cooling fan.

Abstract: Methods and systems for detecting the presence of a leak in a baghouse bag installed in a baghouse system having at least one compartment. The methods include using a system to acquire electrical signals corresponding to the opacity of gas flow through an outlet of a baghouse system during a start-up of one or more compartments of the baghouse system and comparing the electrical signals corresponding to the opacity of the gas flow with electrical signals characteristic of a leak in at least one of the baghouse bags of the baghouse system.

Abstract: A portable gas fractionalization apparatus that provides oxygen rich air to patients is provided. The apparatus is compact, lightweight, and low-noise. The components are assembled in a housing that is divided into two compartments. One compartment is maintained at a lower temperature than the other compartment. The lower temperature compartment is configured for mounting components that can be damaged by heat. The higher temperature compartment is configured for mounting heat generating components. An air stream is directed to flow from an ambient air inlet to an air outlet constantly so that there is always a fresh source of cooling air. The apparatus utilizes a PSA unit to produce an oxygen enriched product. The PSA unit incorporates a novel compressor system which includes the use of free piston linear compressors so as to reduce power consumption, noise and vibration reduction.

Abstract: An air cleaner having a manipulator is disclosed. The manipulator (200) includes a rotary manipulation unit (300), which is provided so as to be movable between a first position, at which the rotary manipulation unit is retracted into the air cleaner, and a second position, to which the rotary manipulation unit is extracted from the air cleaner to enable a user to manipulate the rotary manipulation unit. The manipulator further includes a lift unit (400), which is installed in the air cleaner to move the rotary manipulation unit between the first position and the second position. In the present invention, the manipulator can control several functions of the air cleaner obviating the need for having several control buttons, thus being more convenient for a user. Furthermore, the present invention can prevent water from permeating a PCB mounted in the rot ary manipulation unit, thus preventing malfunction of the encoder unit.

Abstract: A convertible air cleaner adapted for use in a tower or non-tower orientation including: a housing defining an interior chamber; an air filter disposed in the interior chamber; an air inlet through a first outer face of the housing; and an air outlet through a second face of the housing is described. In the air cleaner, the air inlet is disposed substantially opposite the air outlet, and the air cleaner is adapted to create an airflow between the air inlet and the air outlet when the air cleaner is in a tower or a non-tower orientation.

Abstract: In one aspect of the invention a smart air filter monitoring system for a cabinet for electronic devices is provided that includes: an air filter positioned in an air flow so that substantially all the air flows through the filter, the air flow being defined by the cabinet; a light emitting device on a first side of the air filter; at least two light sensors mounted near the air filter, each light sensor directed to the air filter to receive light emitted from the light emitting device after the emitted light has passed through the air filter, the light sensors adapted to generate electrical signals from the emitted light striking the light sensor; an electrical circuit, the electrical circuit generating a signal for indicating that the filter needs to be serviced when the electrical circuit determines that electrical signals received from a combination of the sensors indicates that the filter needs to be serviced.

Abstract: A system (10) for monitoring an operating condition of an electrostatic precipitator rapper system (12) includes a rapper (24) configured to mechanically actuate to disengage pollutants from a plate of the electrostatic precipitator (12). The system also includes a sensor (38, 40) configured to obtain and transmit signals representative of vibration, motion, or current behavior of the rapper; and a processor (52) configured to receive the signals from the sensor and to detect whether the rapper is mechanically actuated.

Abstract: A variable speed fan device includes a housing, a motor, a fan blade, a controller, and a first plurality of discrete light sources. The motor is maintained by the housing and the fan blade is connected to the motor. The controller is electronically coupled to the motor and manages an operational status of the variable speed fan device. The light sources are adapted to emit light from the display panel along a discontinuous perimeter at the exterior face. In an activated state, the light emitted by each light source is visually perceptible an exterior face of the display panel. The controller is programmed to individually activate and deactivate the light sources in a predetermined pattern creating a perception of movement of light about the discontinuous perimeter at the exterior face of the display panel corresponding with an operational status of the variable speed fan device.

Abstract: A self-alarming air cleaner is disclosed. The air cleaner includes an air filter element (1), a light emitting element (2) and a light sensor (3). The light emitting element (2) and the light sensor (3) are both faced to the air filter element (1). The light emitted from the light emitting element (2) is reflected by the air filter element (1) or permeated to the air filter element (1), then forms an area of light attenuation where the light sensor (3) is located. The light emitting element (2) and the light sensor (3) connect with a circuit which has an alarming device. When much dust is accumulated on the air filter element (1), the intensity of the light reaching the light sensor (3) is weakened and the alarming device (4) can give an alarm automatically.

Abstract: A filter assembly for use with compressor assemblies such as oxygen concentrators, ventilators and other breathing apparatus including a compartmented housing member having at least one inlet opening, an outlet opening, a filter member, and an adjustment member associated with the at least one outlet opening for varying the size of the at least one outlet opening for adjusting the amount of ambient air entering the filter assembly.

Abstract: An air filter with a clog-detecting device includes a housing having a wind outlet and a wind intake, a filter unit positioned between the wind outlet and the wind intake, an exhauster disposed between the wind outlet and the filter unit, a magnetic induction unit positioned on the exhauster, and a warning unit assembled on the housing and electrically connected with the magnetic induction unit. A metallic plate is axially fixed on the rotating spindle of a motor and positioned adjacent to the magnetic induction unit, having its upper side formed with at least one projection to enable the magnetic induction unit to induce the metallic plate and produce pulse signals. Thus, by detecting the frequency of the pulse signal, a user can know whether the air filter is clogged or not and proceed to remove the clogged condition to let the air filter continue to work normally.

Abstract: An air purifier includes a housing having an air inlet, an air outlet and an airflow path therethrough. The housing has a top, a bottom and a plurality of sides. An air filter is located within the housing in the airflow path and a motor is located within the housing. The motor includes a motor shaft and a fan is on the motor shaft for urging air into the air inlet, through the airflow path and out of the air outlet. A cover is removably mounted to the housing proximate the air inlet and a base is removably mounted to the housing. The air purifier is positionable in one of a vertical operating orientation when the weight of the housing is supported by the base and a horizontal operating orientation when the weight of the housing is supported by one of the sides of the housing.

Abstract: The present invention relates to a method and a device for providing a zone (2) of clean air at an operation area (3) by means of an air treatment device (1) with a lighting device (25).

Abstract: An exhaust gas purifying apparatus for an internal combustion engine includes a particulate filter for trapping particulates found in the exhaust gases of the engine. The regeneration process for burning the particulates trapped in the particulate filter is executed by performing post injection of fuel. The regeneration process is suppressed according to an amount of fuel injected during post injection.

Abstract: Novel uses and methods of use for inorganic and macroreticulate polymer bonding to metals to control moisture and oxygen in OLED, and other like devices, are provided. Materials having color change capacity are also provided for the removal of moisture from an OLED, where the material changes color upon reaching its capacity and thereby signals the user that the OLED is no longer protected from moisture damage.

Abstract: Data of a barometric pressure that a barometric pressure sensor outputs, and data of an air volume that an air-volume sensor outputs are input into a system control circuit. The system control circuit is provided with a table storing portion. In the table storing portion, a control table is stored. The control table is formed of a plus supplied-voltage value to fan power set by a barometric pressure value and an air-volume value, and a warning instruction. In a case that the warning instruction is selected based on the barometric pressure value and the air-volume value, the system control circuit turns on a warning-use LED so as to inform a user that a filter is clogged.

Abstract: A system for purifying a fluid uses ultra violet (UV) light to inactivate micro-organisms present in the fluid. The system has an arrangement of UV light emitters on perforated plates. The fluid, while passing through perforations in the perforated plates, is exposed to the UV light emitted by the UV light emitters. Micro-organisms present in the fluid pass very close to the UV light emitters. The UV light absorbed by the micro-organisms causes genetic damage and inactivation. The system has feedback units providing feedback about the physical properties of the fluid to a power unit supplying power to the UV light emitters. The power unit varies the amount of power supplied to the UV light emitters, based on the feedback.

Abstract: A semiconductor manufacturing process facility requiring use therein of air exhaust for its operation, such facility including clean room and gray room components, with the clean room having at least one semiconductor manufacturing tool therein, and wherein air exhaust is flowed through a region of the clean room. The facility includes an air exhaust treatment apparatus arranged to (i) receive air exhaust after flow thereof through said region of said clean room, (ii) produce a treated air exhaust, and (iii) recirculate the treated air exhaust to an ambient air environment in the facility, e.g., to the gray room of the facility.

Abstract: Methods and systems for detecting filter rupture are provided. The system includes a light emitter positioned on a first lateral side of a fluid flow and configured to emit light at a predetermined intensity into the fluid flow downstream from a fluid filter, a light receiver positioned on a second lateral side of the fluid flow and configured to receive at least a portion of the emitted light, and a controller configured to receive a signal from said light receiver corresponding to the intensity of the emitted light or the pulsations in the light received, also known as scintillation, said controller configured to generate a corresponding output signal.

Abstract: A method of detecting leaks in the filter bags of a baghouse filter chamber that includes determining when the filter bags have been cleaned and, during a post-cleaning period after the cleaning of the filter bags, determining whether the opacity level of the exhaust of the baghouse filter chamber exceeds a predefined opacity limit. The determining whether the opacity level of the exhaust of the baghouse filter chamber exceeds a predefined opacity limit may include monitoring the opacity level of the exhaust of the baghouse filter chamber with an opacity sensor during the post-cleaning period and comparing the opacity readings during the post-cleaning period with the value of the predefined opacity limit.

Abstract: A method for detecting the cleanliness of a filter. The filter is disposed on an air inlet or an air outlet of a fan. The method includes the following steps. At first, outputting a rotation control voltage to the fan, and an airflow generated by the rotation of the fan flows through the filter. Then, detect an actual rotation rate of the fan, and calculate an actual dust value f1 according to the actual rotation rate and the rotation rate control voltage. Then, a dust upper limit value of the filter is defined. Finally, the cleanliness of the filter is determined according to the actual dust value and the dust upper limit value.

Abstract: An optical gas concentration sensor and method for measuring blood gas based on the light adsorption sensing technique are disclosed. The optical gas concentration sensor comprises a light source, a photo detector, and a gas filtering membrane for separating the indicator and a liquid. A gas in the liquid diffuses to the indicator through the gas filtering membrane so as to change the color of the indicator due to the chemical reaction occurred between the indicator and the gas. Then, the photo detector receives the light passing though the reacted indicator from the light source. The gas concentration is determined based on pH-sensitive absorbance spectrum of the indicator.

Abstract: An air filter system for an internal combustion engine of a vehicle can have an indicator for signaling restricted flow of air through a replaceable air filter member mounted to a filter assembly. At least one sidewall can be associated with the replaceable air filter member to be positioned with an air stream passing through the air filter member. A resettable air filter status indicator can provide a visually perceivable signal external of the filter assembly. The resettable air filter status indicator can be integrally formed in the sidewall for indicating if a mounted air filter member requires replacement in response to air intake differential pressure with respect to atmospheric pressure on a downstream side of air flow through the replaceable filter member being above a predetermined threshold value.

Abstract: A method and system for preventing or minimizing false back pressure faults caused by a new particulate filter in an engine exhaust system. When a new particulate filter is placed in an engine exhaust system, the normal back pressure threshold for the fault detection system is increased by a new filter offset amount. Back pressure faults at the normal level are not recorded for a limited period of engine operation and only records back pressure faults that exceed the normal back pressure threshold by the value of the new filter offset.