Abstract: A method classifies air particulate data. Air sensor data is received from an air sensor. The air sensor data comprises a particulate vector. A machine learning model generates output from the air sensor data using a machine learning model. A notification that uses the machine learning model output is transmitted by a control system.

Abstract: A gas detector comprises a gas detection unit and a filter introducing surrounding atmosphere to the gas detection unit. The filter comprises a gas-permeable organic polymer membrane having an acidic group or a basic group.

Abstract: A method is provided for calibrating a measurement process for a measurement system having a fluid detector, which is provided with a preconcentrator and a fluid sensor. The measurement system for detecting a concentration of a substance to be detected has a sorption phase, during which the fluid to be detected is enriched for a sorption duration (t) in the preconcentrator in a first state, and a measurement phase, in which a concentration of the substance to be detected resulting from the release of the substance to be detected that was enriched in the preconcentrator is measured. The fluid detector is calibrated by adjusting the sorption duration (t).

Abstract: A filter-based air sampler, more specifically a filter-based air sampler capable of integration into small unmanned aerial systems is disclosed. The filter-based air sampler may include a filter assembly which has as its component parts: an open faced air intake component, a filter, and a filter support that has a central supporting grid. The filter assembly may joined to the housing of a fan, such as a centrifugal fan, with the supporting grid of the filter support being disposed over the air inlet of the fan.

Abstract: An artificial intelligence (AI) device includes a display, a communication unit configured to transmit indoor air quality information received from an air quality measurement device and meta information input through the display to an AI server, and a processor configured to receive an air quality analysis report generated based on outdoor air quality information, the indoor air quality information and the meta information from the AI server through the communication unit and display the received air quality analysis report on the display. The air quality analysis report includes a first analysis report including a result of analyzing an indoor air quality condition during a measurement period of the air quality measurement device, and a second analysis report including an air quality type according to the indoor air quality condition and a solution for fine dust management according to the air quality type.

Abstract: A method may include collecting a sample of mud gas during a wellbore drilling operation, associating the sample with a depth of the wellbore, and detecting concentrations of methane, ethane and ethylene. With the detected concentrations, a determination can be made as to the degree of a mud gas artifact event occurring, including determining the differences between the logarithmic values of concentrations of methane and total C2 concentration and the logarithmic values of total C2 concentration and ethane. A visually displayed mud gas log is modified to indicate the degree of the determined mud gas artifact event.

Abstract: In an example, a thermal extraction apparatus includes: a housing having a gas inlet and a gas outlet to receive a gas flow through the housing from the gas inlet to the gas outlet, and a side opening to receive a sample collector, having a sample collector adsorbent containing a vapor sample, into a sample collector location; a pump to generate the gas flow; a heater to heat the sample collector adsorbent of the sample collector to a temperature sufficient to release the vapor sample; a thermal desorption (TD) tube connected with the gas outlet of the housing to receive the gas flow downstream of the sample collector and collect the vapor sample released from the sample collector adsorbent of the sample collector; and a cooling member in heat exchange with the TD tube to cool the TD tube.

Abstract: The present invention reduces the effects from variations in the outside air pressure on particle number counting, and is provided with an exhaust gas processing unit that performs predetermined processing on exhaust gas, a particle number counting unit that counts a number of particles contained in exhaust gas that has passed through the exhaust gas processing unit, a fluid resistance element that is provided downstream from the particle number counting unit, a suction pump that is provided downstream from the fluid resistance element, a gas supply path that is connected to a flow path between the fluid resistance element and the suction pump, and supplies gas to a downstream side of the fluid resistance element, and a flow rate adjustment unit that is provided on the gas supply path, and adjusts a flow rate of the gas that is supplied to the downstream side of the fluid resistance element.

Abstract: A particle counting device includes a scanner probe having a first opening for receiving particles from a sample surface and second openings. Pumps produce a first airstream flowing from the first opening and a second airstream flowing to the second openings. A flow device splits the first airstream into third and fourth airstreams. A first particle detector detects particles in the third airstream. The first particle detector is capable of detecting particles within a first range of particle sizes. A second particle detector detects particles in the fourth airstream. The second particle detector is capable of detecting particles within a second range of particle sizes different from the first range of particle sizes. Control circuitry controls the flow device and the pumps to provide a first flow rate of the third airstream and a second flow rate of the fourth airstream that is larger than the first flow rate.

Abstract: The disclosure relates to a modular device for analyzing gas extracted from a drilling fluid used for drilling a wellbore, comprising a chassis having a power supply system, a fluid distribution and regulation system, and a control module, and a first and second analysis module of different types. The analysis modules comprise a detector for measuring a parameter relative to a content of a gas compound. The chassis comprises a core connector having power, communication and fluid outputs, the analysis modules having a module connector complementary to the core connector. The complementary core and module connectors form a removable connection, easy and quick to connect. The device obtains a measurement from the detector of the first analysis module when connected to the chassis via the core connector and a measurement from the detector of the second analysis module when connected to the chassis via the core connector.

Abstract: A wet chemistry analyzer is provided. The wet chemistry analyzer comprises a reaction chamber configured to receive a reactant solution from a sample inlet and facilitate a process reaction. The wet chemistry analyzer also includes a detection chamber configured to receive a portion of a reaction mixture from the reaction chamber and measure a concentration of a chemical within the reaction mixture. The reaction chamber and the detection chamber are fluidically coupleable such that a portion of the reaction mixture can be directed to flow into the detection chamber to pre-condition a surface inside the detection chamber.

Abstract: A sensor device including a sensor substrate; and a thin film comprising a porous metal organic framework (MOF) on the substrate that presents more than one transduction mechanism when exposed to an analyte. A method including exposing a porous metal organic framework (MOF) on a substrate to an analyte; and identifying more than one transduction mechanism in response to the exposure to the analyte.

Abstract: A device for measuring the quality of an operating substance and/or additive, in particular a reduction agent, stored in a tank, includes a reference container connected to the operating substance and/or the additive via a semi-permeable diaphragm, in which the reference container is filled with a medium which has a known osmotic pressure relative to the used operating substance and/or additive.

Abstract: In various embodiments of the invention, a cargo container can be monitored at appropriate time intervals to determine that no controlled substances have been shipped with the cargo in the container. The monitoring utilizes reactive species produced from an atmospheric analyzer to ionize analyte molecules present in the container which are then analyzed by an appropriate spectroscopy system. In an embodiment of the invention, a sorbent surface can be used to absorb, adsorb or condense analyte molecules within the container whereafter the sorbent surface can be interrogated with the reactive species to generate analyte species characteristic of the contents of the container.

Abstract: A gas monitoring apparatus and system that provides for reliable and accurate monitoring of gaseous hydrogen and other compounds in dielectric oil. The apparatus provides an environment for and is used in conjunction with metal oxide semiconductor sensors. Apparatus for creating a fluid-tight environment for the metal oxide semiconductor and a heating manifold are detailed.

Abstract: A method and a device for the analysis of gas components of a matrix employ two sensors, which each comprise a cavity enclosed by a membrane. Both membranes, each on one side of the matrix and on the other side, are exposed to a purge gas and subsequently, the timeline of the differential pressure ?ps starting at a start time tA is measured, which is created between the sensors as a consequence of permeation of gas components of the matrix and/or the purge gas through both membranes. From the timeline, a point of time tE is determined, at which the measured differential pressure equals the differential pressure at the point of time tA, whereby the gas component of the matrix, which is different from the purge gas, and its genesis is determined from the time difference ?t=tE?tA.

Abstract: A gas concentration image (i.e., concentration vs. position data) in a cross section through a gas plume is obtained. Such measurements can be obtained by using a 2D array of gas sample inlets, or by moving a 1D array of gas sample inlets through the gas plume. By combining a gas concentration image with ambient flow information through the surface of the gas concentration image, the leak rate (i.e., gas flux) from the leak source can be estimated. Gas samples are simultaneously acquired by filling two or more gas sample storage chambers. This is the default operation mode, which is convenient to regard as recording mode. The other operating mode is a playback mode, where the gas samples in the gas sample storage chamber are sequentially provided to a gas analysis instrument. Gas collection via line pixels can be used to compensate for vertical wind speed variation.

Abstract: A sampling device is disclosed. The sampling device includes a labyrinth structure and a sampling tube. The labyrinth structure includes a first baffle plate, a second baffle and a third baffle plate. The second baffle plate in combination with the first baffle plate defines an inlet channel and is configured to receive a portion of oil aerosol containing liquid oil particles. A curved bend is included downstream of the inlet channel and is configured to separate the liquid oil particles from the portion of oil aerosol. The third baffle plate is relatively inclined with respect to the first baffle plate. The third baffle plate in combination with the first baffle plate is configured to drain the separated liquid oil particles. The sampling tube provides the portion of oil aerosol separated of liquid oil particles to a detection device.

Abstract: Process of reducing water, CO2 and N2O in feed air, which: a first adsorbent such as alumina (25-40% volume) and a second adsorbent such as X zeolite (60-75% volume) are used; the online time of the adsorbent is determined by determining the concentration measured by an analyser for CO2 concentration at a position within the length of the second adsorbent when a maximum level of N2O is simultaneously obtained at the downstream end of the second adsorbent in the feed direction, wherein the online time is the time taken from commencing passing the feed air to the first and second adsorbents to the measurement by the analyser of the determined concentration of CO2; at least the second adsorbent is regenerated by heated regeneration gas at a temperature of 140° C.-220° C.; and the molar ratio of the regenerating gas to feed air supplied during one iteration of the cycle is 0.08-0.5.

Abstract: A system for testing the efficiency of a test HEPA filter, the system comprises a dilution system and a sampling system. The dilution system processes samples collected upstream of the test HEPA filter. The dilution system has a test portion and a calibrated portion. The calibrated portion aids in determining the dilution ratio of the test portion thereby rendering the dilution system self-calibrating. The sampling system receives upstream samples via the dilution system, and downstream samples collected directly downstream of the test HEPA filter. The sampling system incorporates a flow rate balancing system to ensure accurate counts with respect to samples collected upstream and downstream of the test HEPA filter. The sampling system works well with particle counters fitted with relatively weak fans to draw in samples for counting; this is achieved by connecting the sampling system to both the inlet and exhaust outlet of a particle counter.

Abstract: A system and method for taking a sample of hydrogen gas and conditioning that sample so that extremely low levels of contamination can be more accurately detected. Initially a sample of hydrogen gas is captured and isolated in a collection chamber. A hydrogen permeable membrane is provided having a first side and a second side. The first side of the hydrogen permeable membrane is exposed to the gas sample held within the collection chamber. The hydrogen gas contained within the gas sample begins to permeate through the hydrogen permeable membrane and exit the collection chamber. This causes the pressure of the gas sample within the collection chamber to decrease. Since contaminants remain in the collection chamber, the concentration of contaminants within the remaining sample increases exponentially. The residual pressure within the collection chamber is measured and converted into a contaminant level reading.

Abstract: Providing a PM emission amount estimation device for the diesel engine wherein the accuracy of the correction in correcting the basic level of the PM emission amount by use of the PM emission amount estimation map can be enhanced; and, the PM emission amount particularly during the transient state of the engine operation condition can be accurately computed so as to estimate, with high precision, the PM emission amount and the PM emission accumulated-amount (integrated amount) during the whole engine operation conditions including the transient state as well as the steady state.

Abstract: A sampling system that contains filter components for collecting and concentrating vapor and particles in high-volume flows. The sample is then vaporized and delivered to a detector at a low-volume flow. The invention also has a sampling probe that contains an air-jet to help dislodge particles from surfaces and a heating lamp to help vaporize compounds on surfaces or objects. The sampling system is especially useful for screening for explosives and other illicit chemicals and toxins on people, baggage, cargo, and other objects.

Abstract: There is provided a monitoring apparatus including a gas sampling apparatus and a sensor that detects a chemical substance included in gas obtained by the gas sampling apparatus. The gas sampling apparatus includes: an air supplying unit that forms an air curtain to form a space that covers a region to which an object to be monitored is included and which is separated from the outside environment; a sampling unit that extracts the gas inside the separated space; and a diffusion gas supplying unit that supplies, into the separated space, an amount of diffusion gas that is at least equal to the sampled amount of the sampling unit, wherein the sampling unit includes a plurality of sampling nozzles disposed at three-dimensionally different positions inside the separated space.

Abstract: A hydrogen sensor assembly is disclosed. A sensor is disposed within a slotted sleeve and a spiral shaped sensor housing surrounds the sensor within the sleeve. The spiral shape applies a centrifugal force to the fluid stream. This results in separation of liquid water from the fluid stream. The sleeve forms an internal inner perimeter of the spiral housing. The sensor housing includes a first opening to facilitate a fluid communication between the sensing element and a fluid stream through the slotted sleeve.

Abstract: Analytes are rapidly desorbed from a carbonaceous sorbent powder with improved quantitation and reduced analyte re-adsorption, thermal degradation, and rearrangement. The sample is distributed in a thin layer onto a desorption surface within a chamber. The layer can be a monolayer. Heating light irradiates the sample through a window, directly and rapidly heating the sample while the desorbed analytes diffuse into a vacuum or are removed by a carrier gas. Finally, the sorbent is flushed from the chamber by a transport gas. The desorption surface can be an inner surface of the window, or a surface of a porous frit that divides the chamber into two sections. The frit can be stainless steel or glass. The carrier gas can be helium, argon, or carbon dioxide. The light source can be a tungsten halogen lamp. A heater can control the chamber temperature according to a heating profile.

Abstract: Device for determining the mass of a particle in suspension or in solution in a fluid. Said device comprises: a first device (2) for the nebulization of the fluid (4) to obtain a flux comprising at least the particle, a second device (6) for the guidance and the aerodynamic focusing of the flux and a third device (12) for determining the mass of the particle by a frequency measurement, said third device comprising at least one gravimetric detector (14), arranged opposite the outlet of the second device, to receive the particle.

Abstract: A gas analyzer includes: a gas measuring portion which performs a measurement on a gas; a case which houses the gas measuring portion; a liquid separator which includes a reservoir for storing a liquid component separated from the gas; a holder portion which holds the liquid separator; and a rotation mechanism which mounts the holder portion to the case.

Abstract: In one example, a sample gas analyzer includes a sample cell configured to receive a gas sample, a sample tube including a passageway that is in communication with the sample cell, and an intake portion. A cleaning element is disposed between, and arranged for fluid communication with, the sample tube and the sample cell, and includes a body having a chamber configured to aid in imparting a rotational motion to a fluid stream entering the chamber. The cleaning element also includes an inlet port that is in communication with the chamber and that is configured and arranged for communication with the atmosphere. Finally, the cleaning element includes an outlet port in communication with the chamber and the sample cell.

Abstract: A device for detecting volatile substances has a containment box with at least one inlet opening for introduction of gas flow, one or more outlet openings of the gas flow, at least one analysis opening, one or more detection sensors arranged in the containment box, and at least one probe insertable in the containment box through at least one analysis opening. When the probe is initially treated by a sample of a substance to be examined and is inserted in the containment box, the gas flow uniformly carries the volatile substances from the sample to one or more sensors. A detection apparatus and a detection method for volatile substances are also described.

Abstract: A particulate monitoring system includes a conduit in which to a pass a fluid sample from an input port to an output port. The particulate monitoring system receives a fluid sample inputted to the conduit through the input port. The fluid sample can include different sizes of particulate matter. The particulate monitoring system controls a flow of the fluid sample through the conduit to age the particulate matter. Gravitational forces cause a portion of the particulate matter in the fluid sample to fall into a basin as opposed to being exhausted through the output port, which is disposed at a vertically higher level of the conduit than the input port. Thus, the particulate monitoring system outputs a portion of the original particulate matter in the fluid sample (e.g., particulate matter that does not drop into the basin out due to gravity) for analysis.

Abstract: A flue gas sensor of a combustion device is disclosed. The flue gas sensor may include a housing and a gas detector disposed within the housing, wherein the gas detector detects or measures at least one gas in a flue gas stream of the combustion device. The housing may also include a water barrier member through which the at least one gas comes into contact with the gas detector.

Abstract: A gas sensor, including a cylindrical outer tube; and a seal member disposed in the outer tube, the seal member including: a lead wire insert hole and an atmosphere communication hole extending in an axial direction thereof. The gas sensor further includes: a protection portion which covers the atmosphere communication hole from the rear end of the gas sensor in the axial direction, the protection portion having a protrusion which protrudes toward a rear side of the gas sensor, and has an opening smaller than an opening of the atmosphere communication hole, wherein the protrusion is disposed at a further front end side of the rear end surface of the seal member.

Abstract: Devices and methods for detecting operational parameters associated with a gas separator used in an electric submersible pump in a wellbore. A fiber optic sensing arrangement is used to detect the operational parameter and includes a fiber optic signal processor and an optic fiber that is associated with the gas separator to provide a signal indicative of the parameter to the signal processor.

Abstract: 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.

Abstract: The invention relates to a device (7) for collecting particles and microorganisms present in ambient air, the device comprising a cyclone enclosure (8) for centrifuging air, the enclosure being of conical or frustoconical shape, external air inlet means (16) for admitting air into the enclosure (8), and air outlet means connected by coupling means (19, 20, 21) to air inlet filter means (4) of an individual motorized respiratory protection appliance (A).

Abstract: A process gas analyzing device is provided. The process gas analyzing device may include a sample gas introducing unit configured to introduce a process gas including a sublimable aromatic compound; a sublimable aromatic compound removing unit configured to remove the sublimable aromatic compound; a process gas pretreatment unit arranged between the sample gas introducing unit and the sublimable aromatic compound removing unit; and a gas analyzing unit arranged in a downstream position of the sublimable aromatic compound removing unit. The sublimable aromatic compound removing unit may include an adsorbent of activated carbon including a non-volatile acid.

Abstract: Certain aspects and examples are directed to sorbent devices and methods of using them. In certain embodiments, a sorbent device comprising a body comprising a sampling inlet, a base and a longitudinal diffusion path between the inlet and the base is provided. In some embodiments, the sorbent device can include at least two sorbent materials fluidically coupled to the longitudinal diffusion path, in which the sorbent materials are arranged from a material with a weakest sorbent strength to a material with a strongest sorbent strength with the weakest sorbent strength material adjacent to the sampling inlet.

Abstract: This application describes apparatus and methods for detecting gas content and compositions in drilling fluids while drilling a subterranean well. More specifically, the apparatus includes an agitated drilling fluid trap incorporating an inertial bypass filter and analyzer to rapidly extract and analyze gases liberated from a drilling fluid sample. The method generally includes the steps of: extracting a gas sample from drilling fluid using an agitation system and inertial by-pass filter; analyzing the gas sample within an analyzer to obtain output signals representing gas content and composition; and, displaying the output in conjunction with other correlated drilling parameters.

Abstract: The device comprises an extractor (53) having an outlet (71) at which a gas stream is sampled. The gas stream contains at least one hydrocarbon to be analyzed and at least one interfering compound. A transport line (54), is connected to the outlet (71) of the extractor (53) to transport the gas stream to an analyzer (55A) comprising a detector being able to measure at least N one of the hydrocarbons to be analyzed contained in this gas stream. The device comprises a chemical reactor (141) located between the extractor (53) and the detector. At least a portion of the extracted gases is transported through the chemical reactor (141) where a selective catalytic reaction of at least one interfering compound is carried out without any substantial reaction of at least one of the hydrocarbons to be analyzed.

Abstract: The present invention aims to provide a gas sensor that can favorably be assembled by proper positioning of a connection terminal relative to a separator and a subassembly unit for such a gas sensor. In an oxygen sensor, a separator has protruding portions formed on a surface of a front end part thereof; an outer connection terminal has an outer fitting portion fixed to outer circumferential surfaces of the protruding portions under its biasing force; and an inner connection terminal has an inner fitting portion fixed to inner circumferential surfaces of the protruding portions under its biasing force. Thus, it is less likely that the outer and inner connection terminals will be displaced in position relative to the separator and is possible to allow proper positioning of the outer and inner connection terminals.

Abstract: The present invention discloses a physiologic sampling pump (PSP) which uses at least one valve placed near the sampling medium to modulate air sampling to follow a person's inhalation rate and to obviate the sluggishness inherent in prior art PSPs caused by varying pump speed and by the propagation time through an air tube that connects the collection medium to prior art pumps thereby also obviating limitations inherent in system response, functionality, and accuracy. Moreover, by maintaining an essentially constant air flow through a cyclone at all times and through the collection medium while sampling, the present invention operates at known collection efficiencies, and is therefore capable of size-selective sampling of particulates as opposed to prior art PSPs that by varying the magnitude of air flow, make the separation efficiencies of pre-collection devices indeterminate and the samples worthless.

Abstract: A sampling system that contains filter components for collecting and concentrating vapor and particles in high-volume flows. The sample is then vaporized and delivered to a detector at a low-volume flow. The invention also has a sampling probe that contains an air-jet to help dislodge particles from surfaces and a heating lamp to help vaporize compounds on surfaces or objects. The sampling system is especially useful for screening for explosives and other illicit chemicals and toxins on people, baggage, cargo, and other objects.

Abstract: Systems and methods for collecting portions of a target sample are disclosed herein. A method for detecting the presence and/or properties of a target sample can include selectively collecting a portion of a target sample with a sample collector and detecting, with the sample collector, the presence of one or more properties of the microscopic portion of the target sample. The method also includes analyzing, with the sample collector, the one or more properties of the microscopic portion of the target sample. Based on the analysis, the method further includes reporting, from the sample collector, a real-time indication of the analysis of the one or more properties of the target sample. The method can also include at least partially removing the microscopic portion of the target sample from the sample collector.

Abstract: Carbon nanotubes are formed on projections on a substrate. A metal, such as nickel is deposited on the substrate with optional platforms, and heated to form the projections. Carbon nanotubes are formed from the projections by heating in an ethylene, methane or CO atmosphere. A heat sensor is also formed proximate the carbon nanotubes. When exposed to IR radiation, the heat sensor detects changes in temperature representative of the IR radiation. In a gas sensor, a thermally isolated area, such as a pixel is formed on a substrate with an integrated heater. A pair of conductors each have a portion adjacent a portion of the other conductor with projections formed on the adjacent portions of the conductors. Multiple carbon nanotubes are formed between the conductors from one projection to another. IV characteristics of the nanotubes are measured between the conductors in the presence of a gas to be detected.

Abstract: A system and method for capturing a sample gas for analysis is disclosed. In one embodiment, the system includes an accumulator that has a variable volume. A volume of the sample gas is fed to the accumulator. The system also has an analyzer. An aliquot of the sample gas is withdrawn from the accumulator and fed to the analyzer. The analyzer analyzes a desired component of the sample gas.

Abstract: A device for removing liquid or solid contaminants such as oil or dust dispersed in air in which an air flow is directed through a space formed by a spiral wall in a cyclonic chamber condenses the particles or droplet which drops down into a collection chamber below the cyclonic chamber while the cleaned air passes out through an outlet extending back up through the cyclonic chamber. A baffle plate array is located at the bottom of the collection chamber composed of spaced apart shallowly inclined partially overlapping plates which captures any cyclonic air flow at the bottom of the collection chamber. This removes contaminants which would otherwise accumulate at the center of the bottom of the collection chamber and be entrained in the air exiting the device.

Abstract: A portable multi-tube air sampler device for capturing samples of trace elements in a suspected contaminated environment which includes a plurality of sample tubes for collecting sample trace elements, parallel inlet and outlet manifolds which minimize the length of the sample inlet path while utilizing short straight sample tubes, a hinged retainer bar mechanism which allows for easy removal and replacement of the various sample tubes, and a removably attachable controller unit which can be installed on the exterior portion of the carrying case for controlling the operation of the sampling protocol. Other embodiments include heated inlet manifold and sample intake paths to prevent contamination accumulation and carryover, a clean cycle option with a filter valved into the inlet flow path to enhance the purging cycle, and a mechanism for converting the present device to a desorbing auto sampler configuration. The present system likewise incorporates a purging cycle prior to each sampling cycle.

Abstract: A hand held detector system that has a housing with a passage that can receive a sample, and a concentrator that captures the sample. The hand held system further includes a single detector coupled to the concentrator and a fluid system that provides fluid communication between the housing passage and the concentrator, and between the concentrator and the detector. The system is powered by a battery. The system may include a controller that heats the concentrator with a temperature profile that causes a first trace molecule to desorb at a time different from the desorption of a second trace molecule. The system and components may be powered by a battery.

Abstract: A filter arrangement for removing impurities from a fluid is disclosed, the filter arrangement (10) includes a plurality of screen portions (18, 20) through which the fluid passes. The screen portions include a first screen portion (18) and a second screen portion (20) separated by a predetermined distance. The predetermined distance can be determined on the basis of a threshold particle length. In one form the filter arrangement (10) is mounted in a housing (16) which is configured to receive two filter elements (18, 20) arranged in a nested configuration. A particle detector using the filter is described.