The gas measurement device includes a filter having a plurality of openings, each opening being variable in size, an adjustment mechanism configured to vary size of the plurality of openings, a first gas sensor configured to detect gas molecules passing through an opening of the filter and output a first measurement value corresponding to the detected gas molecules, and a second gas sensor configured to detect the gas molecules passing through the opening of the filter, output a second measurement value corresponding to the detected gas molecules, and detect gas molecules of a gas species different from the gas molecules detected by the second gas sensor.

A system and a method for testing a filter used in ultrapure water are provided. The method for testing a filter, which is used for removing particles from ultrapure water, comprises: providing a testing solution with particles; detecting the particles in the testing solution by a particle counter; passing the testing solution through a filter; and detecting the particles in the testing solution, which is passed through the filter, by another particle counter.

A method for determining a vehicle heating, ventilation, and air conditioning (HVAC) passenger cabin air filter filtration performance includes determining a vehicle-exterior atmospheric particulate contaminant concentration, a passenger cabin air filter efficiency, and an HVAC airflow rate. The passenger cabin particulate contaminant concentration is calculated from the determined atmospheric particulate contaminant concentration, passenger cabin air filter efficiency, and HVAC airflow rate.

The sensor includes a filter member including cells that trap PM in exhaust gas, electrode members arranged to face each other with the cell interposed and forming a capacitor, an electric heater that executes, when an amount of PM has accumulated in the cells, filter regeneration for combusting and removing the PM, a temperature sensor that acquires the temperature of the filter member, a storage unit that stores therein a reference temperature, which is the temperature of the filter member where the filter regeneration has been executed in a state in which PM is not flowing into the filter member, and estimation units that estimate a PM amount included in the exhaust gas based on (a) an electrostatic capacitance change amount between the electrode members during a regeneration interval and (b) a difference between the temperature acquired by the temperature sensor and the reference temperature during a filter regeneration interval.

A preferred form of the invention is directed to a system and method used to test filters. The system preferably includes a base unit and a probe operably associated with the base unit. The probe is configured to be deployed adjacent the filter being tested while the filter is located in an operating position. The probe is further configured to allow an operator to vary the mode of operation of the base unit from the probe. The system is configured to automatically exhaust any residual test sample from the base unit and the probe when the system changes between testing a sample upstream and downstream of the filter. The system further includes noise suppression on at least one of the upstream test sample and downstream test sample. The system further is configured to detect when the probe is connected to the base unit.

The present invention provides a method for processing a filter to obtain a calibration dust filter, and a method for off-site calibration using the calibration dust filter. In the present invention, a batch of filters that meets specific requirements is screened out as the basal filters, and then the basal filters are processed in an actual environment to obtain the calibration dust filters. The counted number of beta particles is measured before and after sampling, and then a correction factor K is inversely inferred. The beta attenuation suspended particulate analyzer is corrected using the correction factor K. It can be known from a calculation result in an embodiment that, when the beta attenuation suspended particulate analyzer is calibrated using the calibration dust filter, the concentration measured by the calibrated beta attenuation suspended particulate analyzer is more closer to the manually measured concentration, with a CV value roughly equal to 7% to 8%, thus better reflecting variations in pollution concentration of PM in the air.

A water quality measurement system 10 includes: a first pipe 11 through which a first treated water flows; a first branch pipe 11a branching from the first pipe 11 and having a first valve V11; a second pipe 12 through which a second treated water flows; a second branch pipe 12a branching from the second pipe 12 and having a second valve V12; a third pipe 13 connected to the first pipe 11 and the second pipe 12 and through which the first treated water and the second treated water flow; and a water quality measurement device 14 configured to measure a water quality of a treated water flowing through the third pipe 13.

A slurry analysis system (14) for estimating a first characteristic of a slurry (12) having a plurality of particles (18) suspended in a dispersion medium (20) can include a flow restriction assembly (40); a sensor assembly (43) that senses a sensed condition of the slurry (12) as it flows through the flow restriction assembly (40); and a control and analysis system (26) that estimates the first characteristic of the slurry (12) based on the sensed condition. Further, the control and analysis system (26) can select a selected clogging behavior using the sensed condition, and estimate the first characteristic based on the selected clogging behavior.

An air purification system is provided which includes measurement of a concentration of a target pollutant within the air. A gas sensor is used for sensing a concentration of the pollutant (although it will detect other pollutants as well due to cross-sensitivity). A filter is provided which selectively removes the target pollutant while having a significantly smaller effect in reducing other pollutants to which the sensor is cross-sensitive. A gas sensor response is obtained before filtering, a gas sensor response after filtering, and the sensitivity characteristics of the gas sensor to the pollutant are processed, thereby to determine a gas concentration of the pollutant in the air before filtering. In this way, the concentration measurement is better than a direct measurement with the gas sensor as a result of a low selectivity of the gas sensor.

A particulate detection apparatus for controlling a particulate sensor which detects the amount of particulates discharged from a filter for collecting particulates contained in exhaust gas. The particulate sensor includes a detection section configured to electrify particulates contained in exhaust gas so as to produce electrified particulates. The particulate detection apparatus includes a period judgment section, an output obtainment section and an anomaly judgment section. The period judgment section judges whether or not the present point in time is within a previously set anomaly determination period just after completing a filter regeneration process. The output obtainment section obtains a sensor output representing the result of detection by the particulate sensor in the case where the present point in time is judged to be within the anomaly determination period. The anomaly judgment section judges whether or not the particulate sensor is anomalous based on the sensitivity characteristic of the sensor output.