Test chamber apparatus for evaluating filter media

Abstract

The apparatus includes (i) a test chamber having an inlet and an outlet; (ii) an introduction system configured to introduce a test contaminant into the test chamber so that the test contaminant becomes entrained in air flowing from the inlet to the outlet; (iii) a support configured to hold a test substance, the support defining a passageway downstream of the location of the test substance such that air flowing from the inlet to the outlet passes through a filter media before entering the passageway; (iv) an airflow device configured to draw air from within the test chamber through the passageway and the outlet; and (v) a breathing condition simulation system configured to simulate aspects of breathing, an external environment simulation system configured to simulate aspects of an external environment, or both the breathing condition simulation system and the external environment simulation system.

Description

Technical Field

[0001] The present disclosure relates to an apparatus for evaluating a filter medium for a test substance. The present disclosure also relates to an apparatus that simulates a breathing mode, or simulates an external environment mode, or simulates both a breathing mode and an external environment mode.

Background Art

[0002] A mask or other wearable device may include a filter medium that reduces the amount of contaminants from the external environment inhaled by a subject. Examples of contaminants that can be filtered by the medium include compounds or complexes, dust or other particles, and biological substances such as pollen, bacteria, and viruses.

[0003] Airflow patterns and physiological aspects of breathing can affect the ability of a filter medium of a wearable device to filter contaminants and can also affect the ability of the contaminants to interact with the subject. In particular, the air flow rate, humidity, temperature, and carbon dioxide situation during inhalation or exhalation can affect the ability of the medium to filter contaminants or can affect the contaminants themselves.

[0004] Similarly, the external environment in which the contaminants are present and the nature in which the contaminants are introduced into the external environment can affect the ability of the contaminants to interact with the subject. In particular, environmental temperature, humidity, and ultraviolet light can affect the ability of the medium to filter contaminants or can affect the contaminants themselves.

Summary of the Invention

[0005] According to aspects of the present invention, an apparatus is provided for evaluating a filter medium for a test substance. The apparatus comprises a test chamber, an introduction system, a support, an airflow device, and (i) a respiratory condition simulation system, (ii) an external environment condition simulation system, or (iii) both a respiratory condition simulation system and an external environment simulation system. The test chamber includes an inlet and an outlet. The introduction system is configured to introduce a test contaminant into the test chamber so that the test contaminant is mixed into the air flowing from the inlet to the outlet. The support is configured to hold the test substance. The support defines a passage downstream of the location of the test substance so that the air flowing from the inlet to the outlet passes through the filter medium before entering the passage. The airflow device is configured to draw air from inside the test chamber through the passage and the outlet. The respiratory condition simulation system is configured to simulate the manner of respiration. The external environment simulation system is configured to simulate the manner of the external environment.

[0006] Examples of respiration-related aspects that can be simulated by the respiration condition simulation system include one or more of the following: airflow rate, airflow velocity, airflow periodicity, temperature, humidity, acidity, carbon dioxide content, and similar factors. Examples of external environment aspects that can be simulated by the external environment simulation system include one or more of the following: temperature, humidity, ultraviolet light, radiation properties of test pollutants, and similar factors.

[0007] By simulating the respiration pattern, the external environment of the subject, or both the respiration pattern and the external environment, the apparatus of the present invention advantageously enables the evaluation of the test substance under conditions closer to those under which the test substance may be used. Furthermore, the test substance can be evaluated under various conditions to determine its potential efficacy. Such tests may enable, for example, a user, a manufacturer, or both, to determine whether there are specific conditions under which the test substance can function well and specific conditions under which it cannot function well. This allows the user to effectively adopt the test substance. Testing under various conditions allows manufacturers to better instruct users on how to effectively adopt the test substance.

[0008] The apparatus of the present invention may include any suitable test chamber. The test chamber includes an inlet and an outlet. Air may flow through the test chamber from the inlet to the outlet. A check valve or other suitable valve may be operably coupled to the inlet. The valve coupled to the inlet may allow air to flow into the test chamber through the inlet and may also prevent air from flowing out of the test chamber through the inlet.

[0009] The test chamber may be provided with one or more vents. The vents may allow air inside the chamber to escape from the chamber when the relative pressure inside the chamber increases sufficiently or when the relative pressure inside the chamber decreases sufficiently, thereby enclosing air to enter the chamber. The vents may include filters to prevent or reduce test contaminants from leaving the test chamber through the vents, or to prevent contaminants from the surroundings from entering the test chamber through the vents. The filters may include any suitable filter material, such as high-performance air (HEPA) filter material or a carbon filter.

[0010] The test chamber may have an opening into which the test contaminant can be introduced. The opening may be the same as the inlet, or it may be different from the inlet. It is preferable that the test contaminant is introduced into the test chamber through an opening other than the inlet.

[0011] The test chamber may include a frame configured to hold one or more panels defining an enclosed internal space. The frame may be formed from any suitable material. The frame may include an inert material. Any portion of the frame that can communicate with the enclosed internal volume of the test chamber is preferably inert. The frame, or a portion of the frame, may be coated or treated to be inert. The frame may include plastics such as polycarbonate, or metallic materials such as aluminum or stainless steel.

[0012] The panel may be formed from any suitable material. Preferably, at least the surface of the panel defining the interior of the test chamber is inert. Any suitable inert material may be used. The inert material may form the bulk of the panel or be coated on the surface of the panel. Preferably, the surface of the panel defining the interior of the test chamber is hydrophobic.

[0013] Suitable materials for forming the bulk of the panel include glass, plastics, and metals. Suitable plastic materials include polycarbonate, polyetheretherketone (PEEK), and poly(methyl methacrylate) (PMMA). Suitable metal materials include aluminum, stainless steel, and similar materials. The materials may be intrinsically inert, or they may be treated or coated to become inert. For example, the surface may be coated or treated to make it inert.

[0014] At least one panel is preferably transparent to allow visual observation of the enclosed interior space. The entire panel or a portion of the panel may be transparent. Preferably, the entire panel or most of the panel is transparent. Suitable transparent materials for forming the panel include transparent plastic or glass. Visual observation of the enclosed interior space may allow the user of the test apparatus to determine whether the test process is proceeding as expected.

[0015] The test chamber may include two or more panels. For example, the test chamber may include a top panel, a bottom panel, and one or more side wall panels. In some embodiments, the test chamber includes a top panel, a bottom panel, a front side wall panel, a rear side wall panel, a left side wall panel, and a right side wall panel.

[0016] The frame is preferably engaged with the panel to seal it so that the enclosed internal volume of the test chamber is airtight to the surrounding environment. Sealing the test chamber may be important if the contaminants include, for example, infectious or toxic substances. A sealed test chamber can prevent infectious or toxic substances from leaking outside the test chamber. This can prevent users of the test equipment, or anyone near the test equipment, from being exposed to infectious or toxic substances. The panel may be sealed to the frame using one or more sealing elements. Any suitable sealing element may be used. For example, the edges of the panel may be sealed to the frame using synthetic rubber or fluoropolymer elastomer, strips or cords, such as Viton® fluoroelastomer (DuPont, Wilmington, Delaware, USA). The sealing element is preferably inert, or any portion of the sealing element that can communicate with the enclosed internal volume of the test chamber is preferably inert.

[0017] The test chamber can be of any suitable shape. One or more panels may be configured and arranged to achieve the suitable shape of the test chamber. In some embodiments, the test chamber is cubic. The enclosed internal volume and external shape of the test chamber are preferably cubic.

[0018] The test chamber can be of any suitable size. In some embodiments, the enclosed internal volume of the test chamber is 5 to 30 liters, such as 10 to 20 liters.

[0019] The test chamber may be electrically grounded. When a test contaminant is introduced into the test chamber, electrostatic charge accumulation may occur. Electrostatic charge can cause the contaminant or its components to adhere to the inner surface of the test chamber. By electrically grounding the test chamber, the sorption of the contaminant or its components to the inner surface of the test chamber can be reduced. Reducing sorption may increase the amount of contaminant that comes into contact with the filter material of the test substance. Therefore, reduced sorption may allow for accurate evaluation of the test substance under the conditions in which it may be used.

[0020] The internal surfaces of the test chamber that may come into contact with the test contaminant are preferably conductive. Conductive surfaces can effectively provide electrical grounding. If the materials forming the structural elements of the test chamber are not conductive, the surfaces of the structural elements may be coated or treated with a conductive material. Examples of suitable conductive materials include gold, silver, nickel, chromium, titanium, and platinum. In a preferred embodiment, the internal surfaces of the test chamber that may come into contact with the test contaminant include titanium.

[0021] The material forming the opening into which the test contaminant is introduced is preferably inert to the test material and less susceptible to the accumulation of electrostatic charge. In one example, the material forming the opening into which the test contaminant is introduced is made of platinum-coated silicon. The material forming the outlet may be made of platinum-coated silicon. The platinum may be electrically grounded.

[0022] The apparatus of the present invention may include any suitable support. The support may be configured to hold the test substance. Preferably, the support holds the test substance so that the air in the test chamber flows through the filter medium of the test substance before it flows out of the outlet of the test chamber. The support may define a passage communicating with the outlet of the test chamber. The air in the test chamber may flow through the passage to the outlet. The support may be configured to hold the test substance so that the filter medium is located within the passage or above the entrance to the passage.

[0023] The support may extend from the surface of the test chamber, such as the surface of a panel, into the enclosed internal space of the test chamber. For example, the support may extend from the bottom of the test chamber, such as from the bottom panel of the test chamber. The support may include a housing that extends from the bottom of the test chamber, such as the bottom panel of the test chamber. The housing may be attached to the bottom of the test chamber, such as the bottom panel of the test chamber, around the exit of the test chamber. The housing may define a passage.

[0024] The support may include one or more components. In some embodiments, the support includes a housing and an insert. The insert may be inserted into the housing from outside the test chamber through the exit of the test chamber. The insert may engage with the housing in any suitable manner. For example, the insert may engage with the housing through a screw engagement or through a torsion and locking engagement mechanism. Together, the housing and the insert may define a passage for the support.

[0025] The passage of the support may be of any suitable shape and size. For example, the passage may include a rectangular, triangular, circular, or oval cross-sectional shape. The passage preferably includes a circular cross-sectional shape. In some embodiments, the passage has a circular or substantially circular cross-sectional shape with a diameter in the range of 50 millimeters to 80 millimeters. For example, the passage may have a circular or substantially circular cross-sectional shape with a diameter in the range of 40 millimeters to 100 millimeters, or 30 millimeters to 120 millimeters.

[0026] The passage of the support may be of any suitable length. In some embodiments, the passage has a length in the range of 50 millimeters to 80 millimeters. For example, the passage may have a length in the range of 40 millimeters to 100 millimeters, or 30 millimeters to 120 millimeters.

[0027] The cross-sectional shape, size, or shape and size of the passage of the support may be uniform along the length of the passage. The cross-sectional shape, size, or shape and size of the passage may vary along the length of the passage.

[0028] The passage of the support may be configured to simulate the airflow through the human respiratory passage. For example, the passage may have a shape and dimensions similar to one or more of the trachea, larynx, epiglottis, pharynx, or oral cavity, mouth, nasal cavity, and nostrils.

[0029] The support may be configured to form a plurality of passages that communicate with the outlet of the test chamber. The support may be configured to hold the test substance such that air flowing through the test chamber through two or more passages flows through the filter medium of the test substance before flowing through the outlet.

[0030] The support may hold the test substance in any suitable manner. The support may include a surface on which the test substance can be placed. The surface may have any suitable shape. For example, the surface may be flat or curved. The surface may be contoured to complement the surface of the test substance. The surface of the support may be shaped to simulate the surface of a human face.

[0031] The support may include features configured to engage with a holding member of the test substance. For example, if the test substance includes one or more straps, the support element may include a retention such as a post configured to engage with the strap. The support may include a holding element for holding the test substance. For example, the support may include a clamp, a strap, a weighting member, or the like for holding the test substance such that air flowing through a passage from a test chamber passes through a filter medium of the test substance.

[0032] In some embodiments, the support includes a clamping element. The clamping element may apply a force to the test substance to press the test substance against the surface of the support. The clamping element may include a clamping disk. The clamping element may be fixed to a part of the support in any suitable manner. In some embodiments, the clamping element is fixed to a part of the support by a threaded member such as a screw or a bolt. In some embodiments, the clamping element is fixed to the housing of the support by a threaded member.

[0033] One or more sealing members may be disposed between the test substance and the support. For example, an O-ring or other suitable sealing element may be disposed between the test substance and the support.

[0034] The support may be formed from any suitable material. For example, the support may include one or more of a polymeric material, a metallic material, a ceramic material, and a glass material. The support may be formed from one part or multiple parts. The support is preferably formed from a material that can withstand an autoclave.

[0035] The apparatus of the present invention may include any suitable introduction system. The introduction system may be configured to introduce any suitable test contaminant into the test chamber. For example, the test contaminant may include compounds or complexes, dust or other particles, or biomolecules. The biomolecules may include pollen, spores, or pathogens. Pathogens may include bacteria and viruses. Preferably, the test contaminant includes biomolecules. More preferably, the test contaminant includes pathogens. Even more preferably, the test contaminant includes viruses.

[0036] Preferably, the introduction system is configured to introduce the test contaminant in a manner similar to how an object that may be exposed to the test substance may be exposed to the test contaminant. For example, a pathogen may be carried by fine droplets of mucus or saliva containing biomaterials, and can be transmitted from an initial person to a second person by exposure to biomaterials released by the initial person through respiration, coughing, or sneezing. The overall particle size distribution of the suspension of these fine droplets defines their dynamics. In the case of exhaled aerosols such as those from respiration, coughing, sneezing, and talking, the particle size distribution ranges from submicron to submillimeter particle sizes.

[0037] Therefore, the introduction system can be configured to introduce viruses and bacteria into microdroplets having a particle size distribution of 0.1 micrometers to 0.5 millimeters. In some embodiments, the introduction system is adapted to introduce viruses into particles having a size range of 0.1 micrometers to 0.1 millimeters.

[0038] The introduction system can introduce the test contaminant in any suitable form. Preferably, the form is similar to the form to which the object to which the test substance may be used can be exposed. For example, the introduction system can introduce the test contaminant in liquid or solid form. The introduction system can introduce the test contaminant as an aerosol. The aerosol may contain fine liquid or solid particles. If the introduction system introduces bacteria or viruses, it is preferable that the introduction system is configured to introduce the bacteria or viruses into fine droplets.

[0039] The introduction system may include a pressurized gas source or a device for generating an airflow. The pressurized gas or air may flow through a supply source containing the test contaminant. The flow of pressurized gas through the supply source can aerosolize the test contaminant into fine liquid or solid particles. In some embodiments, the introduction system includes an aerosol generator. In some embodiments, the introduction system includes a nebulizer. The nebulizer can introduce the test contaminant in the form of a fine mist.

[0040] The introduction system may introduce the test contaminant directly into the test chamber. The introduction system may introduce the test contaminant upstream or at the inlet of the test chamber. Preferably, the introduction system introduces the test contaminant directly into the test chamber. Regardless of where the introduction system introduces the test contaminant, the introduction system introduces the test contaminant in such a way that it can be mixed with the air flowing from the inlet to the outlet of the test chamber.

[0041] The introduction system may be configured to introduce the test contaminant into the test chamber through an introduction opening on the surface of the test chamber. The surface on which the introduction opening for introducing the test contaminant into the chamber is provided is preferably the top surface of the test chamber.

[0042] The apparatus may include one or more elements that facilitate the flow of the test contaminant, which has entered the air, from the inlet opening of the support to the passage, through a filter medium of the test substance held by the support.

[0043] The apparatus may include one or more elements that reduce the loss of test contaminants to the inner surface of the test chamber. For example, test contaminants may be adsorbed or deposited on the inner surface of the test chamber.

[0044] The apparatus may include a test contaminant inlet tube that facilitates the flow of the test contaminant introduced into the air through an introduction opening in the support's passage, thereby reducing the loss of the test contaminant to the inner surface of the test chamber.

[0045] The apparatus may include guides that facilitate the flow of airborne test contaminants from the support's inlet opening into the passage and reduce the loss of test contaminants to the inner surface of the test chamber.

[0046] Preferably, the apparatus may include a test contaminant inlet tube and a guide. The combination of the test contaminant inlet tube and guide can facilitate the flow of airborne test contaminants from the inlet opening into the support passage and reduce the loss of test contaminants to the inner surface of the test chamber.

[0047] The test contaminant inlet tube may surround the introduction opening and may extend into the test chamber. The test contaminant inlet tube may be formed integrally with the surface of the test chamber, or it may be a separate element that can be fixed to the surface of the test chamber in any suitable manner. For example, the test contaminant inlet tube may be fixed to the upper surface of the test chamber using clamps.

[0048] The test contaminant inlet tube may have any suitable dimensions. The test contaminant inlet tube may have an inner diameter equal to or larger than that of the inlet opening. The test contaminant inlet tube may extend into the test chamber for any suitable distance. For example, the test contaminant inlet tube may extend into the test chamber for a distance of 2 to 15 centimeters, such as 5 to 10 centimeters.

[0049] The test contaminant inlet tube may be made from any suitable material. Preferably, the test contaminant inlet tube contains an inert material. Any portion of the test contaminant inlet tube that may come into contact with the test contaminant is preferably inert. The test contaminant inlet tube, or a portion thereof, may be coated or treated to be inert. The test contaminant contact surface of the test contaminant inlet tube is preferably hydrophobic. Examples of suitable materials for forming the bulk of the test contaminant inlet tube include glass, plastic, and metallic materials. Examples of suitable plastic materials include polycarbonate, polyetheretherketone (PEEK), polystyrene, poly(methyl methacrylate) (PMMA), and poly(tetrafluoroethylene). Examples of suitable metallic materials include aluminum, stainless steel, and similar materials. The material may be intrinsically inert, or may be treated or coated to be inert. Preferably, at least a portion of the test contaminant inlet tube is transparent. More preferably, the entire test contaminant inlet tube is transparent. For sterilization purposes, the test contaminant inlet tube is preferably resistant to one or more of the following: temperatures up to 130°C, organic solvents commonly found in disinfectant solutions such as ethanol or isopropanol, oxidizing agents such as bleach or ozone, and UV irradiation.

[0050] The guide has an inner surface that directs the airflow from the inlet opening toward the passage. The guide extends from a first end to a second end. The first end of the guide may be in proximity to the inlet opening. "In proximity to" includes contact. The first end of the guide may be sealed against the test chamber surface around the inlet opening. For example, an O-ring or gasket may be placed between the first end of the guide and the test chamber surface, together with the inlet opening. When the apparatus is in an assembled configuration, the guide may be fixed against the test chamber surface around the inlet opening. The guide may be fixed against the surface in any suitable manner. For example, the guide may be fixed against the surface around the inlet opening with a clamp. The first end of the guide may define a first inner diameter that is larger than the outer diameter of the inlet opening at the inlet surface.

[0051] The second end of the guide may be in proximity to the passage of the support. "In proximity to" includes being in contact with it. The second end of the guide may define a second inner diameter that is larger than the outer diameter of the test substance. The second end of the guide may be sealed against the support around the position of the test substance. For example, an O-ring or gasket may be placed between the second end of the guide and the surface of the support. When the apparatus is in an assembled configuration, the guide may be fixed to the surface of the support. The guide may be fixed to the surface of the support in any suitable manner. For example, the guide may be fixed to the surface of the support having a clamp by a screw engagement or the like.

[0052] The guide may have an internal surface that defines the internal volume of the guide between the first end and the second end. The internal surface of the guide can direct the test aerosol, which is mixed with air, to flow from the introduction opening into the passage of the support. The guide may have any suitable internal shape and dimensions. For example, the guide may be cylindrical.

[0053] The guide may include one or more air inlets. Air inlets may be beneficial when the guide is sealed to the surface of the test chamber and the surface of the support. Guide air inlets may fluidize the internal volume of the guide to the inlet of the test chamber. Preferably, one or more guide air inlets are located close to the first end of the guide. By being close to the first end of the guide, one or more guide air inlets may be located close to where the test contaminant is introduced, allowing air from the inlet of the test chamber to flow into the internal chamber. As the test contaminant flows through the guide toward the second end, the air may mix with the test contaminant.

[0054] Guide air inlets may be arranged in any suitable manner. If the guide includes multiple guide air inlets, it is preferable that the guide air inlets be arranged axially with respect to the longitudinal axis of the guide. Guide air inlets can have any suitable dimensions. For example, the diameter of a guide air inlet may be 0.2 cm to 3 cm, such as 0.5 cm to 2 cm.

[0055] The guide may be formed from any suitable material. Preferably, the guide contains an inert material. Preferably, any part of the guide that may come into contact with the test contaminant is inert. The guide, or a portion of the guide, may be coated or treated to be inert. Preferably, the test contaminant contact surface of the guide is hydrophobic. Examples of suitable materials for forming the bulk of the guide include glass, plastic, and metallic materials. Examples of suitable plastic materials include polycarbonate, polyether ether ketone (PEEK), polystyrene, poly(methyl methacrylate) (PMMA), and poly(tetrafluoroethylene). Examples of suitable metallic materials include aluminum, stainless steel, and similar materials. The material may be intrinsically inert, or may be treated or coated to be inert. Preferably, at least a portion of the guide is transparent. More preferably, the entire guide is transparent. For sterilization purposes, the guide is preferably resistant to temperatures of one or more degrees up to 130°C, organic solvents commonly found in disinfectant solutions such as ethanol or isopropanol, oxidizing agents such as bleach or ozone, and UV irradiation.

[0056] The guide may be electrically grounded. Electrical grounding may reduce the accumulation of electrostatic charge, which may reduce the amount of test contaminant or components of the test contaminant held by the inner surface of the guide. The inner surface of the guide that may come into contact with the test contaminant is preferably conductive. A conductive surface can make electrical grounding more effective. If the material forming the structural elements of the guide is not conductive, the surface of the structural elements may be coated or treated with a conductive material. Examples of suitable conductive materials include gold, silver, nickel, chromium, titanium, and platinum.

[0057] The test contaminant inlet tube may be received within the guide, close to the first end of the guide. Therefore, the inner diameter of the guide at the first end may be larger than the outer diameter of the test contaminant inlet tube. The test contaminant inlet tube may extend within the internal volume of the guide for any suitable distance. If the guide includes one or more guide air inlets, it is preferable that the test contaminant inlet tube extends beyond the guide air inlets toward the second end of the guide within the internal volume of the guide. Therefore, the air entering the guide air inlets may flow along the outer surface of the test contaminant inlet tube, promoting the flow of more laminar and less turbulent air through the guide. This laminar flow may form a sheath around the test contaminant entering the apparatus from the introducer opening. The sheath may remain at least partially along the length of the guide as the air flows toward the second end of the guide, which can reduce the interaction between the test contaminant and the inner surface of the guide. This may reduce the loss of the test contaminant and increase the mass of test contaminant available for testing.

[0058] If the guide includes multiple guide air inlets arranged axially with respect to the longitudinal axis of the guide, a radially symmetric arrangement may increase the homogeneity of the flow of the test contaminant and increase the mixing of the test contaminant with air, thereby resulting in a more temporally and spatially homogeneous introduction of the test contaminant into the test material held by the support.

[0059] Advantageously, the test contaminant inlet tube and guide can address problems associated with aerosol loss that may be experienced in test setups without the test contaminant inlet tube and guide. In the absence of the test contaminant inlet tube and guide, air entering one or more test chamber walls at one or more inlets can generate turbulence. When the air mixes with the test contaminant, some of the test contaminant may be carried by the turbulent air to the inner surfaces of the test chamber where contaminant loss may occur. Such losses can reduce the total mass of the test contaminant available for analysis, thereby reducing experimental sensitivity. Furthermore, losses can be difficult to predict. Therefore, the mass of the test contaminant passing through the test substance may not be well-characterized, and the filtration efficiency of the test substance may not be accurately calculated.

[0060] In addition to turbulence that can result from a test apparatus lacking a test contaminant inlet tube and guide, non-uniform mixing of the test contaminant and dilution air may occur as a result. Thus, the test contaminant may reach the test material in a non-uniform manner both temporally and spatially. This may affect the filtration efficiency of the test material, potentially leading to localized overloading of the test material by the test contaminant and affecting the experimental results.

[0061] These confounding factors can be reduced by guides and test contaminant inlet pipes.

[0062] The apparatus for evaluating the filter medium of the test substance of the present invention may include any suitable airflow device. The airflow device is configured to draw air from inside the test chamber through a passage in the support and through the outlet of the test chamber. When the test substance is held by the support, the air flows through the filter medium of the test substance as it flows from the test chamber to the passage.

[0063] Air can be drawn out of the test chamber through the outlet using any suitable airflow device. For example, the airflow device may include a negative pressure source relative to the pressure inside the test chamber, or a device that generates a relative negative pressure for drawing air out of the chamber through the outlet. Examples of devices that can generate a relative negative pressure include a venturi pump, a fan, or any other suitable device. Such devices are referred to herein as vacuum pumps.

[0064] The airflow device may include a flow meter, a transducer for measuring atmospheric pressure, or a flow meter and transducer. The flow meter, transducer, or flow meter and transducer may be operably coupled to a controller. The controller may be coupled to a device that generates relative negative pressure. The controller may be adapted to regulate the airflow through the substance under test based on input from the flow meter, transducer, or flow meter and transducer.

[0065] The airflow device may be configured to introduce air into the test chamber through an outlet and a passage in the support. When the test material is held by the support, the air flows through the filter medium of the test material as it flows from the outlet and passage into the test chamber. Air may be introduced into the test chamber through the outlet using any suitable airflow device. For example, the airflow device may include a source of relative positive pressure to the pressure in the test chamber, or a device that generates relative positive pressure for introducing air into the test chamber through the outlet. Examples of sources and devices that can generate relative positive pressure include a pressurized air source, a fan, an air pump, or any other suitable device for introducing air into the chamber through the outlet.

[0066] The airflow device may include a piston pump, where movement of the piston in a first direction draws air out of the test chamber, and movement of the piston in a second, opposite direction introduces air into the test chamber. The piston pump can advantageously provide physiological volume and air movement.

[0067] The airflow device may include a respiratory device, which may also be called a ventilator.

[0068] The airflow device may be connected to the outlet of the test chamber or the passage of the support in any suitable manner. For example, a conduit may be connected to the airflow device and the outlet or passage of the support to carry air from the airflow device to the outlet or from the outlet to the passage, or from the passage to the airflow device.

[0069] The conduit may be coupled to a manifold to allow coupling to an airflow device configured to draw air out of the test chamber, and to an airflow device configured to introduce air into the test chamber.

[0070] The airflow device may include one or more valves. For example, a first valve may be coupled to a device configured to draw air out of the test chamber. A second valve may be coupled to a device configured to introduce air into the test chamber. The valves may be opened and closed at appropriate times to allow air to flow into or out of the test chamber. The valves may advantageously allow for precise flow control.

[0071] The filter may be located within the conduit between the outlet and the airflow device. The filter can protect the airflow device from contaminants, such as pollutants, that may be present in the test chamber. The filter can protect the airflow device from moisture in the air flowing from the test chamber. The filter can also ensure that the air from the airflow device to the test chamber is clean and free from contamination, such as pollutants. The filter may include a HEPA filter, a carbon filter, or both a HEPA filter and a carbon filter.

[0072] The apparatus for evaluating the filter medium of the test substance of the present invention may include a respiratory condition simulation system. The respiratory condition simulation system can simulate any suitable aspect of respiration, such as one or more of the following: airflow rate, airflow velocity, airflow duration, airflow periodicity, direction or flow, temperature, humidity, carbon dioxide content, and pH. Preferably, the respiratory condition simulation system simulates one or more aspects of human respiration.

[0073] A respiratory condition simulation system may be operably coupled to an airflow device. The respiratory condition simulation system may include an airflow device controller configured to cause the airflow device to simulate one or more modes of respiration of an object that may be using a test substance. For example, the airflow device controller may be configured to cause the airflow device to simulate one or more of the following: respiratory cycle period, inhalation volume, inhalation rate, inhalation time, expiratory volume, expiratory rate, and expiratory time.

[0074] The airflow device controller is preferably configured to cause the airflow device to alternately (i) draw air from the test chamber through the support passage and outlet, and (ii) introduce air into the test chamber through the outlet and support passage.

[0075] The airflow controller may be configured to cause the airflow device to draw any appropriate amount of air from the test chamber through the outlet. The airflow controller may be configured to cause the airflow device to draw a constant or variable amount of air from the test chamber through the outlet. The flow controller may be configured to cause the airflow device to draw air from the test chamber through the outlet at any appropriate speed. The airflow controller may be configured to cause the airflow device to draw air from the test chamber through the outlet at a constant or variable speed. The airflow controller may be configured to cause the airflow device to draw air from the test chamber through the outlet for any appropriate time.

[0076] For example, the airflow device may be configured to draw 0.2 to 6 liters, preferably 0.5 to 3 liters, of air from the test chamber through the support passage and outlet for a period of 0.5 to 15 seconds, preferably 1 to 6 seconds. These flow rates, flow volumes, and durations simulate many of the conditions associated with human inhalation.

[0077] An airflow device controller may be configured to cause the airflow device to introduce any appropriate amount of air into the test chamber through its outlet. An airflow device controller may be configured to cause the airflow device to introduce a constant or variable amount of air into the test chamber through its outlet. An airflow device controller may be configured to cause the airflow device to introduce air into the test chamber through its outlet at any appropriate rate. An airflow device controller may be configured to cause the airflow device to introduce air into the test chamber through its outlet at a constant or variable rate. An airflow device controller may be configured to cause the airflow device to introduce air into the test chamber through its outlet for any appropriate duration.

[0078] For example, the airflow device may be configured to introduce 0.2 to 6 liters, preferably 0.5 to 3 liters, of air into the test chamber through the support's passages and outlets for a period of 0.5 to 15 seconds, preferably 1 to 6 seconds. These flow rates, flow volumes, and durations simulate most conditions associated with human exhalation.

[0079] The airflow device controller may be configured to control the airflow device in any suitable manner. For example, if the airflow device includes a piston pump, the airflow device controller may be operably coupled to the motor of the piston pump. The airflow device controller may be operably coupled to a valve that regulates the velocity of the airflow from the airflow device, such as a vacuum pump, drawn from the test chamber. Alternatively, or additionally, the airflow device controller may be operably coupled to the motor of the airflow device to draw air from the test chamber, such as a vacuum pump. As another example, the airflow device may be operably coupled to a valve configured to regulate the velocity of the airflow from the airflow device, such as a pressurized air source, to the test chamber.

[0080] The respiratory condition simulation system may be configured to introduce air of a predetermined humidity into the test chamber through the outlet of the test chamber and through the passage of the support. If the test substance is held by the support, the air of the predetermined humidity may flow through the filter medium of the test substance.

[0081] The respiratory condition simulation system may include a humidifier. The humidifier may be operably coupled to an airflow device. Both the humidifier and the airflow device may be configured such that the air introduced into the test chamber through the outlet and support passages has a controlled humidity.

[0082] The respiratory simulation system may include any suitable humidifier. For example, the humidifier may have a reservoir for holding water. Air flowing from the airflow device into the test chamber may flow over the water, adding humidity to the air. The humidifier may have a wick for drawing water from the reservoir. Air flowing from the airflow device into the test chamber may have increased relative humidity because water from the wick may be transferred to the air as the airflow passes through it. The airflow device may include an ultrasonic vibrator or other suitable device to facilitate the movement of water from the reservoir to the air as the air passes through the reservoir. The ultrasonic vibrator may include an element positioned in contact with the water in the reservoir. When the element vibrates ultrasonically, water droplets may form. Air passing through the water may come into contact with the water droplets, increasing the humidity of the air. The humidifier may also include a heater for heating the water in the reservoir. Heating the water may allow more moisture to be contained in the air flowing through the heated water. The humidifier may include an impeller that agitates the water, dispersing it throughout the air that flows through the storage section.

[0083] The humidity-controlled air preferably has a relative humidity similar to that of the air exhaled by a person. For example, the humidity-controlled air may have a relative humidity in the range of 70 percent to 100 percent.

[0084] A respiratory condition simulation system may include a respiratory humidity sensor and a respiratory humidity controller operably coupled to the respiratory humidity sensor. The respiratory humidity sensor may be located at any suitable location downstream of the humidifier. In this context, downstream is with respect to the air flowing from the humidifier through the outlet and through the passage of the support into the test chamber. For example, the humidity sensor may be located in a conduit through which the humidity-controlled air flows toward the outlet of the test chamber, or in a passage of the support. The respiratory humidity controller may be operably coupled to a component of the humidifier configured to control the amount of water transferred to the air flowing through or past the humidifier. For example, the respiratory humidity controller may be operably coupled to an ultrasonic vibrator. The ultrasonic vibrator may include a piezoelectric element configured to vibrate ultrasonically when an electric current is applied. The respiratory humidity controller element may be configured to apply an appropriate current to the piezoelectric element.

[0085] A respiratory condition simulation system may be configured such that the air in close proximity to the test substance has a temperature that simulates the temperature in close proximity to the mouth or nose of a person who may use the test substance. The respiratory condition simulation system may also include a heating system. The heating system may be arranged and configured such that the air introduced into the test chamber by an airflow device through an outlet and support passage has a controlled temperature while in the passage.

[0086] The breathing condition simulation system may include any suitable heating system. The heating system may include a heater and a water circulation system capable of circulating the water heated by the heater. The water circulation system may include a pump for circulating the water. The heating system may include a heat conduction element that transfers heat from the circulating heated water to the air flowing from the airflow device to the passages of the support and to the air flowing into the test chamber. The heating system may be configured to heat the support.

[0087] The heating system may include a resistive element that can be heated to transfer heat from an airflow device to the air flowing into the test chamber through a support passage. Any suitable resistive element such as a resistance wire, resistance plate, resistance grid, or resistance gel may be employed.

[0088] The heating system may be configured to heat by induction. For example, an induction heating element may be used to heat water in a circulating system or to transfer heat to air flowing from an airflow device into the test chamber through a passage in a support.

[0089] Components of a support or conduit that carry air from an airflow device through a passage in the conduit or support may be thermally conductive. For the purposes of this disclosure, a material is considered "thermally conductive" if it has a thermal conductivity of 5 watts / meter Kelvin [w / (m·K)] or more, such as 10 w / (m·K) or more or 50 w / (m·K) or more. Components may be in thermal contact with the heat-conducting elements of a heating system. Heat from the heating system can be transferred from the airflow device through the passage in the support to the air flowing into the test chamber.

[0090] The heating system may include a breathing temperature sensor and a breathing temperature controller operably coupled to the breathing temperature sensor. The breathing temperature controller may also be operably coupled to a heater, such as a resistive element or a water heater. The breathing temperature sensor may be located in any suitable location. Preferably, the breathing temperature sensor is located within or adjacent to a passage in the support.

[0091] The heating system may be configured such that the air flowing through the support passages near the test material has any suitable temperature. For example, the heating system may be configured such that the air introduced by the airflow device through the outlet and the passage to the test chamber has a temperature in the range of 28 to 45 degrees Celsius when it is in the passage. Preferably, the air has a temperature in the range of 30 to 42 degrees Celsius. More preferably, the air has a temperature in the range of 35 to 40 degrees Celsius.

[0092] The heating system or components of the heating system may be included in a support that defines the passage.

[0093] A respiratory condition simulation system may be configured to bring the air flowing from the outlet of the test chamber through the support passage to a carbon dioxide content similar to that of the exhaled breath of a subject who may use the test substance. When the test substance is held by the support, the carbon dioxide-controlled air flows through the filter medium of the test substance.

[0094] The respiratory condition simulation system may include a carbon dioxide concentration controller system. The carbon dioxide controller system may be configured to introduce carbon dioxide into the air introduced into the test chamber through an outlet and a support passage. The percentage of carbon dioxide in the air within the passage may be adjusted to a desired range.

[0095] The carbon dioxide controller system may include a pressurized carbon dioxide source. The pressurized carbon dioxide source may contain carbon dioxide at a desired concentration. If the pressurized carbon dioxide source contains carbon dioxide at a desired concentration, it can function as a component of an airflow device configured to introduce air into a test chamber.

[0096] A pressurized carbon dioxide source may contain a carbon dioxide concentration higher than the desired concentration. For example, the source may contain carbon dioxide at a concentration of 50 volume percent or more. The source may contain carbon dioxide at a concentration of up to 100 volume percent. If the pressurized carbon dioxide source contains carbon dioxide at a concentration higher than the desired concentration, the carbon dioxide may be introduced from the source into the air flowing from the airflow device to the outlet of the test chamber and into the passages of the support in any suitable manner. The carbon dioxide controller system may include a mixer that mixes carbon dioxide from the source with air from the airflow device.

[0097] A carbon dioxide controller system may include a carbon dioxide sensor and a carbon dioxide controller operably coupled to the carbon dioxide sensor. The carbon dioxide controller may be operably coupled to a valve that controls the amount of carbon dioxide from a supply source introduced into the air. The carbon dioxide sensor may be located in any suitable location. Preferably, the carbon dioxide sensor is located within or in close proximity to a passage in a support.

[0098] A carbon dioxide controller system can be configured such that the air flowing through the support passages adjacent to the substance under test has any appropriate carbon dioxide concentration. For example, a carbon dioxide controller system can be configured such that the air introduced by an airflow device through the outlet and passages to the test chamber has a carbon dioxide concentration in the range of 2 to 7 volume percent, preferably 4 to 5 volume percent.

[0099] A respiratory condition simulation system may be configured to bring the air flowing through the outlet of the test chamber, through the passage of the support (and thus through the filter medium of the test substance), to a pH similar to that of the exhaled breath of a subject who may be exposed to the test substance. For example, a respiratory condition simulation system may include a pH controller system. The pH controller system may include a pH controller device configured to control the pH of the air caused by an airflow device introduced through the outlet and the passage to the test chamber.

[0100] The pH controller system may include an acid pump configured to introduce the acid into the air, which is supplied to the storage unit to contain the acid and is introduced into the test chamber by an airflow device through an outlet and a support passage. The acid pump may be adapted to deliver the acid to the storage unit of a humidifier, such as the humidifier described above. The acid pump may pump the acid from the acid storage unit to the humidifier storage unit to lower the pH of the water in the humidifier. This may lower the pH of the air that comes into contact with the pH-reduced water.

[0101] The acid storage section may contain any suitable solution containing an acid. For example, the solution may contain citric acid.

[0102] The pH controller system may include a base pump, which is coupled to a storage unit to contain a base and is configured to introduce the base into the air caused by an airflow device introduced into the test chamber through an outlet and a support passage. The base pump may be adapted to deliver the base to a storage unit of a humidifier, such as the humidifier described above. The base pump may pump the base from the base storage unit to the humidifier storage unit to increase the pH of the water in the humidifier. This may increase the pH of the air in contact with the pH-increased water.

[0103] The base storage section may contain any suitable solution containing a base. For example, the solution may contain a sodium citrate solution.

[0104] A pH controller system may include a pH sensor and a pH controller operably coupled to the pH sensor. The pH controller may be operably coupled to an acid pump, a base pump, or both an acid pump and a base pump. The pH sensor may be located in any suitable location. Preferably, the pH sensor is located within or adjacent to a passage in a support.

[0105] A pH controller system can be configured to bring an arbitrary appropriate pH to the air flowing through a support passage in close proximity to the substance under test. For example, a pH controller system can be configured to bring a pH in the range of 8 to 8.3, preferably about 8.1 to 8.2, to the air introduced by an airflow device through the outlet and passage to the test chamber.

[0106] The respiratory condition simulation system may include a respiratory condition simulation system controller that functions as one or more of the following: a respiratory humidity controller, a respiratory temperature controller, a carbon dioxide controller, and a pH system controller, or is operablely coupled to them. The respiratory condition simulation system controller may be operablely coupled to a user interface. The user interface may be used to set the desired respiratory simulation conditions to be employed when evaluating the filter medium of the test substance.

[0107] The apparatus for evaluating the filter medium of the test substance of the present invention may include any suitable external environment simulation system. The external environment simulation system can simulate any suitable mode of the environment in which the user may use the test substance. For example, the external environment simulation system may be configured to control one or more or all of the following: the temperature of the air introduced into the test chamber, the temperature of the air inside the test chamber, the humidity of the air introduced into the test chamber, the humidity of the air inside the test chamber, the concentration of environmental air pollutants in the air introduced into the test chamber, the concentration of environmental air pollutants in the air inside the test chamber, and the UV light introduced into the test chamber. The external environment simulation system can simulate an indoor or outdoor environment.

[0108] The external environment simulation system may be configured to control the temperature of the air introduced into the test chamber, the temperature of the air inside the test chamber, or both. The external environment simulation system may also include an external temperature control system configured to allow temperature-controlled air to enter the test chamber through an inlet. The external environment simulation system may include any suitable external temperature control system.

[0109] The external temperature control system may include an external system heater configured to heat the ambient air so that the air introduced into the test chamber is at a higher temperature than the ambient air, a cooler configured to cool the ambient air so that the air introduced into the test chamber is at a lower temperature than the ambient air, or both a heater and a cooler.

[0110] The external temperature control system may include any suitable heater. The heater may include resistive elements, inductive elements, etc. The heater may also include a heat conduction element capable of transferring heat from the resistive element to the air entering the test chamber through the inlet.

[0111] The external temperature control system may include any suitable cooler. The cooler may include a Peltier cooler, a refrigerant compressor, etc. The cooler may include a heat conduction element from which heat can be transferred from the air entering the test chamber through the inlet.

[0112] The external temperature control system may include a water circulation system in which water of different temperatures above and below the ambient air circulates. The external temperature control system may also include a heat conduction element that transfers heat from the circulating water to the ambient air, or from the ambient air to the circulating water.

[0113] The external temperature control system may comprise an external system temperature sensor and an external system temperature controller operably coupled to the external system temperature sensor. The external system temperature controller may also be operably coupled to a heater, a cooler, or both a heater and a cooler. The external system temperature sensor may be positioned at any suitable location. Preferably, the external system temperature sensor is positioned to detect the temperature inside the test chamber.

[0114] The external temperature control system may be configured to ensure that the air flowing into the test chamber through the inlet has any suitable temperature. For example, if the external temperature control system is configured to simulate an outdoor environment, it may be configured to bring the air flowing into the test chamber through the inlet to a temperature in the range of -40°C to 45°C, preferably 0°C to 30°C, more preferably 10°C to 27°C. If the external temperature control system is configured to simulate an indoor environment, it may be configured to ensure that the air flowing into the test chamber through the inlet has a temperature in the range of, for example, 17°C to 26°C.

[0115] The external environment simulation system may be configured to control the humidity of the air introduced into the test chamber, the humidity of the air inside the test chamber, or both the humidity of the air introduced into the test chamber and the humidity of the air inside the test chamber. The external environment simulation system may include an external humidity control system configured so that humidity-controlled air enters the test chamber through an inlet. The external environment simulation system may include a humidifier, a dehumidifier, or both, positioned and adapted to increase or decrease the relative humidity of the air entering the test chamber.

[0116] The external temperature control system may comprise an external system humidity sensor and an external system humidity controller operably coupled to the external system humidity sensor. The external system humidity controller may also be operably coupled to a humidifier, a dehumidifier, or a humidifier and dehumidifier. The external system humidity sensor may be positioned at any suitable location. Preferably, the external system humidity sensor is positioned to detect humidity within the test chamber.

[0117] The external humidity control system may be configured to ensure that the air flowing into the test chamber through the inlet has any appropriate humidity. For example, if the external humidity control system is configured to simulate an outdoor environment, it may be configured to bring the air flowing into the test chamber through the inlet to a relative humidity in the range of 20 percent to 90 percent, preferably 50 percent to 70 percent. If the external humidity control system is configured to simulate an indoor environment, it may be configured to bring the air flowing into the test chamber through the inlet to a relative humidity in the range of, for example, 30 percent to 55 percent.

[0118] External environment simulations may be configured to introduce ultraviolet (UV) light into a test chamber. For example, an external environment simulation system may include a UV light source configured to allow UV light to pass through the interior of the test chamber. The UV light source may be located inside or outside the test chamber. If the UV light source is outside the test chamber, the test chamber may include a UV-transparent portion that allows UV light from the light source to pass through a portion of the test chamber and reach the interior of the test chamber. External environment simulations may be configured to control the intensity or spectral output of the UV light source. By varying the intensity of the UV light source, different times of day, different times of year, and different weather conditions can be simulated. Preferably, the UV source emits light with a spectrum similar to sunlight. For example, the UV source may emit light with wavelengths in the range of 300 to 400 nanometers. Sunlight emits 95 percent UV A light with wavelengths in the range of 315 to 400 nanometers and 5 percent UV B light with wavelengths in the range of 280 to 315 nanometers. Preferably, the UV light source emits 95 percent UV A rays and 5 percent UV B rays.

[0119] The external environment simulation system may include a UV sensor, such as a photodiode, and a UV source controller operably coupled to the UV sensor. The UV source controller can control the intensity or spectral output of the optical signal emitted by the UV light source based on the input from the UV sensor. The UV sensor is preferably positioned to detect UV light within the test chamber.

[0120] The external environment simulation system may be configured to introduce ambient air pollutants into the test chamber. The external environment simulation system may be configured to control the amount of air pollutants introduced into the test chamber, the amount of air pollutants in the air within the test chamber, or both. The ambient air pollutants may be introduced into the test chamber in any suitable manner.

[0121] For example, an external environment simulation system may introduce environmental air pollutants in liquid or solid form. The external environment simulation system may introduce test pollutants as aerosols. These aerosols may contain fine liquid or solid particles. The external environment simulation system may include an external system aerosol generator positioned and configured to generate an aerosol containing environmental air pollutants, such that the aerosols can be drawn into the test chamber through the inlet of the test chamber. The external system aerosol generator may include an external system nebulizer for introducing environmental pollutants as a fine mist.

[0122] The external environment simulation system may include a sub-chamber into which environmental pollutants are introduced. The sub-chamber may communicate with the inlet of the test chamber so that air flows through the sub-chamber before flowing through the inlet. The environmental pollutants may be mixed into the air flowing into the test chamber through the inlet.

[0123] The external environment simulation system may include a dilution valve operably coupled to the inlet. The dilution valve may be configured to introduce environmental air pollutants into the test chamber through the inlet.

[0124] The external environmental simulation system may include an environmental pollutant sensor and an environmental pollutant controller operably coupled to the environmental pollutant sensor. The environmental pollutant controller may be operably coupled to an environmental pollutant introducer, such as an external system aerosol generator, to control the amount of environmental pollutants generated and carried by the air entering the inlet of the test chamber, based on input from the environmental pollutant sensor. The environmental pollutant controller may be operably coupled to a dilution valve to control the amount of pollutants carried into the air entering the inlet of the test chamber, based on input from the environmental pollutant sensor.

[0125] The external environment simulation system can be configured to introduce any appropriate environmental pollutants into the system. Examples of environmental pollutants include particulate matter, ozone, carbon monoxide, sulfur dioxide, nitrogen dioxide, lead, smoke, and smog.

[0126] The environmental simulation system may include an operable environmental system controller that functions as one or more of the following: an external system temperature controller, an external system humidity controller, a UV source controller, and an environmental pollutant controller, or is coupled to them. The environmental system controller may be operablely coupled to a user interface. The user interface may be used to set the desired environmental simulation conditions to be employed when evaluating the filter medium of the substance under test.

[0127] An apparatus for evaluating the filter medium of a test substance may include a main system controller. The main system controller may function as one or more controllers of a respiratory simulation system, one or more controllers of an environmental simulation system, or one or more controllers of a respiratory simulation system and one or more controllers of an environmental simulation system, or may be operably coupled. The main system controller may be operably coupled to a user interface. The user interface may be used to set one or more desired respiratory simulation system parameters, one or more desired environmental simulation system parameters, or one or more desired respiratory simulation system parameters and desired environmental simulation system parameters, which are employed when evaluating the filter medium of the test substance.

[0128] The apparatus for evaluating the filter medium of the test substance of the present invention may include a test contaminant collector. The test contaminant collector may be positioned in the airflow path downstream of the test substance. In this context, downstream means with respect to the air flowing out of the test chamber and out of the outlet of the test chamber through the passage of the support. Preferably, the test contaminant collector is positioned so that the air drawn in from the test chamber through the passage of the support comes into contact with the test contaminant collector.

[0129] A test contaminant collector may include material for collecting test contaminants. The collection material may be held in a device for collecting test contaminants. The collection material or collection device may be impermeable to air or permeable to air. If the collection material and collection device, which may be the same material, are permeable to air, it is preferable that the permeable collection material extends through the passage of the support. Thus, all air flowing through the passage may come into contact with the collection material.

[0130] If the collecting material or collecting device is impermeable, air may flow around the collecting material or collecting device after coming into contact with it. It is preferable that the impermeable collecting material or collecting device does not pass across the passages of the support so that air can flow around the impermeable material or collecting device and continue to flow downstream of the impermeable material or collecting device. The air in the passages of the support may be directed toward the collecting material so that all or substantially all of the air flowing from the test chamber through the passages comes into contact with the collecting material.

[0131] The air carrying the test contaminant preferably affects the collection material. The funnel element may be positioned within a passage of the support upstream of the surface of the collection material, or may form part of it. In this context, upstream refers to the air flowing from the test chamber through the passage of the support to the outlet of the test chamber. Any suitable funnel element may be used. For example, the funnel element may include a cascade impactor ring. The funnel element may guide the air flowing from the test chamber through the passage of the support to the collection material. The collection material that the air contacts or impacts may be positioned at the center of the passage.

[0132] The test contaminant collector and passage of the support may be configured to allow air to continue flowing through the passage, contact with or impact with the collected material or collection device, and then exit through the exit of the test chamber. In some embodiments, the test contaminant collector or passage includes one or more lateral openings with respect to the impact surface of the test contaminant collector. Lateral openings may allow air to flow around the surface of the collector after impacting the surface of the test contaminant collector, through the passage, and continue flowing out of the exit of the test chamber.

[0133] In some embodiments, the test contaminant collector includes a cup and a holder configured to receive and hold the cup. The cup or the material placed inside the cup may include a surface that comes into contact with or strikes air flowing through a passage in the support. The holder may have one or more lateral openings with respect to the position where the cup is received. One or more lateral openings may be annular. The cup may be positioned within a passage in the support and held such that one or more lateral openings of the holder communicate with the passage.

[0134] The test contaminant collector may include any suitable material for collecting the test contaminant when the air carrying the test contaminant comes into contact with the test contaminant collector. For example, the test contaminant collector may include a hydrogel, a filter, or other material capable of capturing the test contaminant when the air carrying the test contaminant comes into contact with the test contaminant collector. Hydrogels may be particularly suitable for use when the test contaminant contains biological substances such as bacteria or viruses. The test contaminant collector may include any suitable hydrogel, such as agarose, polyacrylamide, or alginate gel.

[0135] Hydrogels can maintain the viability of captured bacteria or viruses. Therefore, the test contaminant collector or components of the test contaminant collector containing the hydrogel that has captured biological test contaminants such as bacteria or viruses may be removed from the test apparatus. Once removed, the characteristics of the captured bacteria or viruses may be evaluated outside the test apparatus. For example, the number of collected pathogens, or the viability or pathogenicity of the collected pathogens may be evaluated.

[0136] In some embodiments, the test contaminant collector or a part of the test contaminant collector may be removed from the test apparatus without accessing the inside of the test chamber. For example, the test collector or a component of the test collector may be removed through the outlet of the test chamber. In some embodiments, the test collector may be removed through the outlet of the test chamber while the test substance is being held by the support.

[0137] The support may include a housing positioned within the test chamber. The housing may be mounted in the test chamber around the outlet of the test chamber. The support may include an insert that can be inserted through the outlet of the test chamber for removable coupling with the housing. The insert may be coupled to the housing in any suitable manner. For example, the insert may be coupled to the housing by screw engagement or by a twist-and-lock engagement mechanism. The insert may engage with the housing by twisting in one direction or disengage from the housing by twisting in another direction. The insert may hold a test contaminant collector. The test contaminant collector may be removed from the insert after the insert has been disengaged from the housing and pulled out through the outlet of the test chamber.

[0138] The insert may have a handle that extends beyond the outer surface of the test chamber when the insert is fully engaged with the housing. The handle may be used to facilitate engaging and disengaging the insert from the housing.

[0139] The ability to remove the test contaminant collector without accessing the inside of the test chamber can be advantageous when the test contaminant may be a hazardous substance. This is particularly advantageous when the test contaminant may be an infectious substance such as bacteria or viruses. Therefore, users of the test system can remove the test collector without being exposed to any hazardous or infectious substances that may be present inside the test chamber.

[0140] Since the test contaminant collectors can be removed and replaced, the system can be used to study the effects of various respiratory effects, environmental effects, or combinations of respiratory and environmental effects.

[0141] The material used to collect the test contaminant in the test collector may be removed and studied for any appropriate purpose. For example, the mass of the collected test contaminant may be determined. Aerosol dosimetry analysis may be performed. If the test contaminant is a pathogen, its pathogenicity may be tested. For example, the viability of the pathogen may be tested. If the pathogen infects cells such as viruses, the ability of the collected pathogen to infect cells may be tested.

[0142] In some embodiments, the test contaminant collector includes cultured cells. The cultured cells may simulate tissue. For example, the cultured cells may include lung epithelial cells cultured to simulate lung tissue. Such a cell culture system may be particularly advantageous when the test contaminant includes a respiratory virus such as the SARS-CoV-2 virus, or another test contaminant known to affect the lungs.

[0143] In some examples, the cultured cells may include skin cells such as keratinocytes, dermal epithelial cells, and one or more of the same.

[0144] In some embodiments, the test contaminant collector includes a first cell or simulated tissue type, as well as hepatocytes or simulated liver tissue. Preferably, the test contaminant collector includes simulated lung tissue and simulated liver tissue. The effect of hepatic metabolism on the test contaminant can be evaluated by culturing the first type of cell or simulated tissue having hepatocytes or lung tissue. In particular, the effect of test contaminant metabolites on the first cell or tissue type may be evaluated.

[0145] Hepatocytes or simulated liver tissue and the first cell or simulated tissue type may be in contact or separated. If hepatocytes or simulated liver tissue are separated from the cultured first cell or simulated tissue type, the separated cells are preferably fluid-communicated. In some embodiments, the test contaminant collector includes a microfluidic circulation system that circulates fluid between the separated cells. The circulated fluid may provide the movement of molecules and materials between the separated cells. The circulated fluid may provide nutrients to the cultured cells or simulated tissue and remove waste products from the cultured cells or simulated tissue. The test contaminant collector may be positioned so that one or both cell types are first exposed to the test contaminant by contact with air flowing through the support channels.

[0146] The funnel element may be positioned within or part of the support or passage to direct the air flowing through the passage toward the cultured cells, or it may form part of or part of the passage. Before contacting the cultured cells, the airflow may be dispersed to prevent damage to the cells from the airflow. Any suitable air dispersal device may be used. For example, the inner diameter of the passage may be increased in the region upstream of the cultured cells. The increased inner diameter may serve to slow and disperse the air before contacting the cells.

[0147] In some examples, cells are cultured on a permeable membrane. Air flowing through the support channels may come into contact with or collide with the permeable membrane. Test contaminants that come into contact with the permeable membrane may migrate through the membrane and come into contact with the cells.

[0148] The apparatus for evaluating filter media of a test substance according to the present invention can be used to evaluate any suitable test substance, including any suitable filter media. For example, the test substance may include heating, ventilation, and air conditioning (HVAC) equipment, filters for occupational, environmental, and medical devices including filter media, and filters for personal protective equipment including filter media. Preferably, the filter media is employed in a device configured to be worn over or placed over the mouth, nose, or mouth and nose of a subject. Such devices include masks and ventilators.

[0149] The filter medium may prevent the passage of at least some test contaminants and may substantially alter the test contaminants, or it may prevent the passage of at least some test contaminants and may substantially alter the test contaminants.

[0150] Filter media capable of substantially altering test contaminants may be advantageous when the test contaminants include toxic test contaminants, infectious test contaminants, pathogenic test contaminants, or similar substances. Such filter media can advantageously make the test contaminants non-toxic, non-infectious, non-pathogenic, etc.

[0151] If the test apparatus of the present invention includes a test contaminant collector, the captured test contaminants may be evaluated for toxicity, infectivity, pathogenicity, etc. Different respiratory conditions, external environmental conditions, or the effects of respiratory conditions and external environmental conditions on toxicity, infectivity, pathogenicity, etc., can also be tested using the test apparatus of the present invention.

[0152] In some embodiments, the test apparatus of the present invention can be used without the test substance, including a filter medium. For example, the test apparatus can be used to study the effects of a test contaminant in the absence of a filter medium.

[0153] According to an aspect of the present invention, an apparatus for evaluating a filter medium of a test substance is provided. The apparatus includes a test chamber, an introduction system, a support, an airflow device, and a test contaminant collector. As described above, the test chamber has an inlet and an outlet. As described above, the introduction system is configured to introduce the test contaminant into the test chamber so that the test contaminant is mixed with the air flowing from the inlet to the outlet. As described above, the support is configured to hold the test substance. The support defines a passage downstream of the location of the test substance so that the air flowing from the inlet to the outlet passes through the filter medium before entering the passage. As described above, the test contaminant collector is positioned in the airflow path within the passage so that air drawn in from the test chamber through the passage comes into contact with the test contaminant collector. As described above, the airflow device is configured to draw air from inside the test chamber through the passage and the outlet. The test contaminant preferably includes biological material. The biological material preferably includes pathogens. The pathogens preferably include viruses.

[0154] Furthermore, the singular forms “a,” “an,” and “the” as used herein also include embodiments that have plural objects, unless otherwise clearly defined by the context.

[0155] The terms “preferred” and “preferred” refer to embodiments of the present invention that may provide certain advantages under specific circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the enumeration of one or more preferred embodiments does not imply that other embodiments are unhelpful, nor is it intended to exclude other embodiments from the scope of this disclosure, including the claims.

[0156] As used herein, “to provide” in the context of providing an apparatus or system means to manufacture, purchase, or otherwise obtain an apparatus or system.

[0157] Any directions or orientations mentioned herein, such as “upper,” “lower,” “left,” “right,” “upward,” “downward,” and other directions or orientations, are described herein for clarity and brevity, but are not intended to limit the actual devices or systems. The devices and systems described herein may be used in a number of directions and orientations.

[0158] "Inert" means that an inert material does not substantially react chemically or physically with the component being tested, such as an aerosol, and that the inert material does not substantially emit any substances that could affect the test results by contaminating the component being tested. Similarly, an inert material may not substantially absorb the component being tested.

[0159] "Adsorption" refers to either absorption or adsorption, or both. Absorption is the phenomenon or process in which molecules are incorporated into the bulk phase, which may be a liquid or solid material. Adsorption refers to the adhesion of molecules to a surface.

[0160] As used herein, a “hydrophobic” surface is a surface that exhibits water-repellent properties. A surface may be considered hydrophobic if it exhibits a water contact angle greater than 90 degrees. The “water contact angle” is the angle conventionally measured through a liquid, where the liquid / vapor interface intersects with the solid surface. The water contact angle quantifies the wettability of a solid surface by a liquid via Young's equation. The contact angle may be measured using a contact angle goniometer, which uses a microscope objective lens to directly observe the angle. The contact angle may also be observed through a microscope objective lens, or it may be determined by observing water droplets deposited on the surface.

[0161] As used herein, “controller” refers to one or more hardware devices, one or more software or firmware programs, or one or more hardware devices and software or firmware programs that manage or direct the flow of data between two or more entities. A controller may include memory, an application-specific integrated circuit (ASIC) state machine, a digital signal processor, a gate array, a microprocessor, or an equivalent discrete logic circuit or integrated logic circuit. A controller may include memory containing instructions that cause one or more components of the circuit to perform functions or aspects of the controller. The functions attributed to the controller in this disclosure may be embodied as one or more of software, firmware, and hardware. A controller may include a microprocessor.

[0162] Non-limiting examples are provided below without exhaustion. One or more features of these examples may be combined with one or more features of other examples, embodiments, or aspects described herein.

[0163] Example 1 Apparatus for evaluating a filter medium for a test substance, comprising: (i) a test chamber including an inlet and an outlet; (ii) an introduction system configured to introduce a test contaminant into the test chamber such that the test contaminant is mixed into air flowing from the inlet to the outlet; (iii) a support configured to hold the test substance, the support defining a passage downstream of the location of the test substance such that air flowing from the inlet to the outlet passes through a filter medium before entering the passage; (iv) an airflow device configured to draw air from inside the test chamber through the passage and the outlet; and (v) a respiratory condition simulation system configured to simulate the manner of respiration, an external environment simulation system configured to simulate the manner of the external environment, or both the respiratory condition simulation system and the external environment simulation system. Example 2 The apparatus according to Example 1, wherein the introduction system is configured to introduce the test contaminant into the test chamber through an introduction opening on the surface of the test chamber. Example 3 The apparatus according to Example 2, comprising a test contaminant inlet pipe surrounding the inlet opening and extending into the test chamber. Example 4 The apparatus according to Example 2 or Example 3, comprising a guide having an inner surface for directing airflow from an inlet opening toward a passage, wherein the guide extends from a first end to a second end. Example 5 The apparatus according to Embodiment 4, wherein the first end of the guide is close to the introduction opening and the second end of the guide is close to the passage. Example 6 The apparatus according to Example 4 or 5, wherein the first end of the guide is sealed against the introduction surface around the introduction opening. Example 7 The apparatus according to Embodiment 6, wherein the first end of the guide defines a first inner diameter, and the first inner diameter is larger than the outer diameter of the introduction opening on the introduction surface. Example 8 The apparatus according to Example 6 or 7, comprising the test contaminant inlet pipe of Example 3, wherein the first inner diameter is greater than the outer diameter of the test contaminant inlet pipe. Example 9 The apparatus according to any one of Examples 4 to 8, wherein the second end of the guide is sealed to a support around the position of the substance to be tested. Example 10 The apparatus according to Example 9, wherein the second end of the guide defines a second inner diameter, and the second inner diameter is greater than the outer diameter of the test substance. Example 11 The apparatus according to any one of Examples 4 to 10, wherein the guide defines the internal volume of the guide between the first end and the second end. Example 12 The apparatus according to Example 11, comprising the test contaminant inlet tube of Example 3, wherein the test contaminant inlet tube extends within the internal volume of the guide. Example 13 The apparatus according to Example 10 or 11, wherein the guide is cylindrical. Example 14 The apparatus according to any one of Examples 11 to 13, wherein the guide includes a first guide air inlet. Example 15 The apparatus according to Example 14, wherein the first guide air inlet is located close to the first end of the guide. Example 16 The apparatus according to Example 14 or 15, wherein the first guide air inlet connects the internal volume of the guide to the inlet of the test chamber. Example 17 The apparatus according to any one of Examples 14 to 16, comprising the test contaminant inlet tube of Example 3, wherein the test contaminant inlet tube extends into the internal volume of the guide, beyond the first guide air inlet, toward the second end of the guide. Example 18 The apparatus according to any one of Examples 11 to 17, wherein the guide defines a second guide air inlet. Example 19 The apparatus according to Embodiment 18, wherein the first guide air inlet and the second guide air inlet are arranged axially with respect to the longitudinal axis of the guide. Example 20 The apparatus according to Example 18 or 19, wherein the second guide air inlet connects the internal volume of the guide to the inlet of the test chamber. Example 21 The apparatus according to any one of Examples 4 to 20, wherein the guide is electrically grounded. Example 22 The apparatus according to any one of Examples 1 to 21, wherein the airflow device is further configured to introduce air into the test chamber through an outlet and a passage. Example 23 The apparatus according to Example 22, wherein the respiratory condition simulation system comprises an airflow device controller operably coupled to the airflow device, the airflow device controller configured to cause the airflow device to alternately draw air from the test chamber through a passage and an outlet and introduce air into the test chamber through the outlet and a passage. Example 24 The apparatus according to Example 23, wherein the airflow device controller is configured to draw 0.2 to 6 liters, preferably 0.5 to 3 liters, of air into the airflow device from the chamber through the passage and outlet for a period of time from 0.5 to 15 seconds, preferably 1 to 6 seconds. Example 25 The apparatus according to Example 23 or 24, wherein the airflow device controller is configured to introduce 0.2 to 6 liters, preferably 0.5 to 3 liters, of air into the chamber through the outlet and passage over a period of 0.5 to 15 seconds, preferably 1 to 6 seconds. Example 26 The apparatus according to any one of Examples 21 to 25, wherein the airflow device includes a piston pump. Example 27 The apparatus according to any one of Examples 23 to 25, wherein the airflow device includes (i) a positive pressure pump and a first valve operably coupled to a positive pressure pump, and (ii) an operable vacuum pump and a second valve operably coupled to the pump, and an airflow device controller operably coupled to the first valve and the second valve to alternately open and close the first valve and the second valve between (a) air drawn from the test chamber through a passage and an outlet and (b) air introduced into the test chamber through an outlet and a passage. Example 28 The apparatus according to any one of Examples 22 to 27, wherein the respiratory condition simulation system is operably coupled to an airflow device and includes a humidifier configured such that the air introduced into the test chamber through the outlet and passage has a controlled humidity. Example 29 The apparatus according to Example 28, comprising a respiratory humidity sensor, wherein the respiratory condition simulation system is configured to detect the relative humidity in the air caused by an airflow device introduced into the test chamber through an outlet and a passage. Example 30 The apparatus according to Example 29, wherein the respiratory condition simulation system comprises a respiratory humidity sensor and a respiratory humidity controller operably coupled to a humidifier, the respiratory humidity controller being configured to increase or decrease the relative humidity of the air introduced into the test chamber through the outlet and passage to the humidifier in order to maintain a controlled humidity based on input from the respiratory humidity sensor. Example 31 The apparatus according to Example 29 or 30, wherein the controlled humidity is a relative humidity in the range of 70 percent to 100 percent. Example 32 The apparatus according to any one of Examples 22 to 31, wherein the respiratory condition simulation system comprises a heating system configured such that the air introduced into the test chamber through the outlet and passage by an airflow device has a controlled temperature when it is in the passage. Example 33 The apparatus according to Example 32, wherein the heating system is configured such that the air introduced into the test chamber through the outlet and passage by the airflow device has a temperature in the range of 28 to 45 degrees Celsius, preferably 30 to 38 degrees Celsius, when it is in the passage. Example 34 The apparatus according to Example 32 or 33, wherein the heating system is configured to heat at least a portion of the support holding the substance of the test to a temperature in the range of 35 to 40 degrees Celsius, preferably 36 to 38 degrees Celsius. Example 35 The apparatus according to any one of Examples 32 to 34, wherein the heating system includes a heating element. Example 36 The apparatus according to Example 35, wherein the heating system comprises a breathing temperature sensor and a breathing temperature controller, the breathing temperature controller being operably coupled to the breathing temperature sensor and a heating element, and the breathing temperature sensor is configured to increase or decrease the temperature of the heating element to maintain a controlled temperature based on the input from the temperature sensor. Example 37 The apparatus according to Example 35 or Example 36, wherein the heating element includes a resistive element or an inductive heating element. Example 38 The apparatus according to any one of Examples 32 to 37, wherein the heating system includes a heating element configured to heat water, and a pump for circulating the heated water. Example 39 The apparatus according to any one of Examples 22 to 38, comprising a respiratory condition simulation system, a carbon dioxide concentration controller system configured to introduce carbon dioxide into the air introduced into the test chamber through an outlet and a passage, thereby allowing the proportion of carbon dioxide in the air within the passage to be adjusted to a desired range. Example 40 The apparatus according to Example 39, wherein the desired range of the percentage of carbon dioxide in the air is 2% to 7% by volume, preferably 4% to 5% by volume. Example 41 The apparatus according to Example 39 or 40, wherein the carbon dioxide concentration controller system is configured to introduce carbon dioxide from a pressurized carbon dioxide source having a carbon dioxide concentration greater than a desired range into the air introduced into the test chamber through an outlet and a passage. Example 42 The apparatus according to Embodiment 41, wherein the carbon dioxide concentration controller system comprises a carbon dioxide detector and a carbon dioxide controller operably coupled to a valve communicating with the carbon dioxide detector and a carbon dioxide supply source, the carbon dioxide controller being configured to allow the valve to introduce more or less carbon dioxide from the supply source into the air based on an input from the carbon dioxide detector. Example 43 The apparatus according to any one of Examples 22 to 42, wherein the respiratory condition simulation system comprises a pH controller system, the pH controller system comprising a pH controller device configured to control the pH of air caused by an airflow device introduced into the test chamber through an outlet and a passage. Example 44 The apparatus according to Example 43, wherein the pH controller system is configured to ensure that the air has a pH of 8.0 to 8.3, preferably 8.1 to 8.2. Example 45 The apparatus according to Example 43 or 44, comprising an acid pump configured to introduce the acid into the air caused by an airflow device that is coupled to a storage section for containing the acid and introduced into the test chamber through an outlet and passage. Example 46 The apparatus according to Example 45, comprising a pH sensor configured to detect the pH of the air caused by an airflow device introduced into the test chamber through an outlet and a passage, and a pH controller operably coupled to the pH sensor, wherein the pH controller is configured to increase or decrease the amount of acid added to the air by the acid pump based on the input from the pH sensor. Example 47 The apparatus according to Example 45 or 46, with reference to any one of Examples 28 to 31, wherein the humidifier is provided with a water source and the acid pump is configured to introduce acid from an acid-containing storage unit to the water source. Example 48 The apparatus according to any one of Examples 43 to 47, comprising a base pump configured to introduce the base into the air caused by an airflow device that is coupled to a storage unit for containing the base and introduced into the test chamber through an outlet and passage. Example 49 The apparatus according to Example 48, comprising a pH controller system comprising a pH sensor configured to detect the pH of air caused by an airflow device introduced into the test chamber through an outlet and a passage, and a pH controller operably coupled to the pH sensor, wherein the pH controller is configured to increase or decrease the amount of base added to the air in the base pump based on the input from the pH sensor. Example 50 The apparatus according to Example 48 or 49, wherein the humidifier is provided with a water source and the base pump is configured to introduce a base from an acid-containing storage unit to the water source. Example 51 The apparatus according to any one of Examples 1 to 50, wherein the apparatus includes an external environment simulation system. Example 52 The apparatus according to Example 51, wherein the external environment simulation system includes an external temperature control system configured such that temperature-controlled air enters the test chamber through an inlet. Example 53 The apparatus according to Example 52, wherein the external temperature control system includes a heater configured to heat the ambient air so that the air introduced into the test chamber is at a higher temperature than the ambient air. Example 54 The apparatus according to Example 52 or 53, wherein the external temperature control system includes a cooler configured to cool the ambient air so that the air introduced into the test chamber is at a lower temperature than the ambient air. Example 55 The apparatus according to any one of Examples 51 to 54, wherein the external temperature control system comprises an external system temperature sensor configured to detect the temperature of the air in a test chamber, and an external system temperature controller operably coupled to the external system temperature sensor, the external system temperature controller being configured to control an external system heater or cooler to change the temperature of the air in the test chamber based on input from the temperature sensor. Example 56 The apparatus according to any one of Examples 51 to 55, wherein the external environment simulation system is equipped with an external humidity control system and configured so that humidity-controlled air enters the test chamber through an inlet. Example 57 The apparatus according to Embodiment 56, comprising an external system humidity sensor configured to detect the relative humidity of the air entering the test chamber through the inlet. Example 58 The apparatus according to Example 56 or 57, wherein the external humidity control system includes an external system humidity sensor configured to detect the relative humidity in the air within the test chamber. Example 59 The apparatus according to any one of Examples 56 to 58, wherein the external humidity control system is configured to include a dehumidifier and introduce air into a test chamber having a relative humidity lower than that of the ambient air. Example 60 The apparatus according to Embodiment 59, referencing Embodiment 57 or 58, wherein the external humidity control system comprises an external system humidity controller operably coupled to an external system humidity sensor and a dehumidifier, and the breathing humidity controller is configured to adjust the dehumidifier based on input from the external system humidity sensor. Example 61 The apparatus according to any one of Examples 56 to 60, wherein the humidity control device is equipped with a humidifier and configured to introduce air into a test chamber having a relative humidity higher than that of the ambient air. Example 62 The apparatus according to Embodiment 61, with reference to Embodiment 57 or 68, wherein the external humidity control system comprises an external system humidity controller operably coupled to an external system humidity sensor and a humidifier, and the breathing humidity controller is configured to adjust the humidifier based on input from the external system humidity sensor. Example 63 The apparatus according to any one of Examples 51 to 62, wherein the external environment simulation system includes an ultraviolet light source configured such that ultraviolet light passes through the interior of the test chamber. Example 64 The apparatus according to Example 63, wherein the ultraviolet light source is located outside the test chamber. Example 65 The apparatus according to Example 63, wherein the ultraviolet light source is located inside the test chamber. Example 66 The apparatus according to any one of Examples 63 to 65, comprising an ultraviolet light sensor and an ultraviolet source controller operably coupled to the ultraviolet light sensor, wherein the ultraviolet source controller is operably coupled to an ultraviolet light source and configured to change the intensity or spectral output of the light source based on an input from the ultraviolet light sensor. Example 67 The apparatus according to any one of Examples 51 to 66, wherein the external environment simulation system is configured to introduce environmental air pollutants into the test chamber. Example 68 The apparatus according to Example 67, wherein the external environment simulation system comprises a dilution valve operably coupled to the inlet of the test chamber, the dilution valve being configured to introduce environmental air pollutants into the test chamber through the inlet. Example 69 The apparatus according to Example 67 or 68, wherein the external environmental system comprises an external system aerosol generator, and the external system aerosol generator is configured to generate an aerosol containing environmental air pollutants so that the aerosol can be drawn into the test chamber through the inlet. Example 70 The apparatus according to Example 69, wherein the external system aerosol generator includes an external system nebulizer. Example 71 The apparatus according to any one of Examples 67 to 70, comprising an external environment simulation system, an environmental pollutant sensor, and an environmental pollutant controller operably coupled to the environmental pollutant sensor, wherein the environmental pollutant controller is operably coupled to the external system aerosol generator according to Example 69 or 70, the dilution valve of Example 67, or both the external system aerosol generator according to Example 69 or 70 and the dilution valve of Example 67, and controls the amount of environmental air pollutants entering the test chamber through the inlet based on input from the environmental pollutant sensor. Example 72 The apparatus according to any one of Examples 1 to 71, comprising a test contaminant collector positioned in an airflow path within a passage so that air drawn in from a test chamber through the passage comes into contact with the test contaminant collector. Example 73 The apparatus according to Example 72, wherein the test contaminant collector includes a collection material configured to capture the test contaminant. Example 74 The apparatus according to Example 73, wherein the collection material configured to capture the test contaminant is air-permeable. Example 75 The apparatus according to Example 74, wherein the collected material extends into the passageway. Example 76 The apparatus according to Example 73 or 74, wherein the collected material is placed inside or on the collection device. Example 77 The apparatus according to Embodiment 76, wherein the collection device is positioned in a passage so that air continues to flow around the collection device, through the passage, and through the outlet. Example 78 The apparatus according to Example 77, wherein the collection device comprises a cup. Example 79 The apparatus according to Example 78, wherein the test contaminant collector further comprises a holder configured to receive a cup, the holder having one or more openings lateral to the position in which the cup is received. Example 80 The apparatus according to any one of Examples 73 to 78, further comprising a funnel element located upstream of the collected material, wherein the funnel element directs the air drawn in through the passage toward the collected material. Example 81 The apparatus according to any one of Examples 73 to 80, wherein the collected material includes a hydrogel. Example 82 The apparatus according to any one of Examples 73 to 81, wherein the collected material includes a filter material. Example 83 The apparatus according to any one of Examples 73 to 81, wherein the collected material includes cultured cells. Example 84 The apparatus described in Example 83, in which cultured cells simulate tissue. Example 85 The apparatus according to Example 83 or 84, wherein the cultured cells include skin cells, lung cells, or lung cells and skin cells. Example 86 The apparatus according to Example 85, wherein the cultured cells include lung cells. Example 87 The apparatus according to Example 86, further comprising cultured liver cells. Example 88 The apparatus described in Example 86, wherein cultured liver cells are in contact with cultured lung cells. Example 89 The apparatus described in Example 86, which separates cultured liver cells from cultured lung cells. Example 90 The apparatus according to Example 89, further comprising a microfluidic circulation system for circulating fluid between separated cells. Example 91 The apparatus according to any one of Examples 1 to 90, wherein the introduction system is configured to directly introduce the test contaminant into the test chamber. Example 92 The apparatus according to any one of Examples 1 to 91, wherein the introduction system includes an aerosol generator. Example 93 The apparatus according to Example 92, wherein the aerosol generator includes a nebulizer. Example 94 The apparatus according to any one of Examples 1 to 93, wherein the test chamber is electrically grounded. Example 95 The apparatus according to any one of Examples 1 to 94, wherein the airflow device comprises a vacuum pump configured to generate negative pressure relative to the pressure in the test chamber and to flow air out of the test chamber through a passage and through an outlet. Example 96 The apparatus according to Example 95, wherein the airflow device includes a valve configured to control the flow of air from the test chamber to the vacuum pump. Example 97 The apparatus according to Example 96, wherein the airflow device includes a flow meter, a transducer for measuring atmospheric pressure, or a flow meter and a transducer. Example 98 The apparatus according to Embodiment 97, wherein the airflow device comprises a flow meter, a transducer, or a flow controller operably coupled to a flow meter and transducer, and the flow controller is operably coupled to a vacuum pump to regulate the airflow through the system based on inputs from the flow meter, transducer, or flow meter and transducer. Example 99 Apparatus for evaluating a filter medium for a test substance, comprising: (i) a test chamber including an inlet and an outlet; ii) an introduction system configured to introduce a test contaminant into the test chamber such that the test contaminant is mixed into air flowing from the inlet to the outlet; (iii) a support configured to hold the test substance, the support defining a passage downstream of the position of the test substance such that air flowing from the inlet to the outlet passes through a filter medium before entering the passage; (iv) an airflow device configured to draw air from inside the test chamber through the passage and the outlet; and (v) a test contaminant collector positioned in the airflow path within the passage such that air drawn in from the test chamber through the passage comes into contact with the test contaminant collector. Example 100 The apparatus according to Example 99, wherein the test contaminant collector is removable from the passageway without accessing the inside of the test chamber. Example 101 The apparatus according to Example 100, wherein the support comprises a housing attached to the test chamber around the outlet, the support comprises an insert configured to engage and disengage with the housing, the insert is insertable through the outlet, and the insert holds a test contaminant collector. Example 102 The apparatus according to any one of Examples 99 to 101, wherein the test contaminant collector includes a collection material configured to capture the test contaminant. Example 103 The apparatus according to Example 102, wherein the collection material configured to capture the test contaminant is air-permeable. Example 104 The apparatus according to Example 103, wherein the collected material extends into the passageway. Example 105 The apparatus according to Example 102 or 103, wherein the test contaminant collector comprises a collection device, and the collected material is placed inside or on the collection device. Example 106 The apparatus according to Example 105, wherein the collection device is positioned in a passage so that air continues to flow around the collection device, through the passage, and through the outlet. Example 107 The apparatus according to Example 106, wherein the collection device comprises a cup. Example 108 The apparatus according to Example 107, wherein the test contaminant collector further comprises a holder configured to receive a cup, the holder having one or more openings lateral to the position in which the cup is received. Example 109 The apparatus according to any one of Examples 102 to 108, further comprising a funnel element positioned upstream of the collected material, wherein the funnel element directs air drawn through a passage toward the collected material. Example 110 The apparatus according to any one of Examples 102 to 109, wherein the collected material includes a hydrogel. Example 111 The apparatus according to any one of Examples 102 to 109, wherein the collected material includes a filter material. Example 112 The apparatus according to any one of Examples 102 to 109, wherein the collected material includes cultured cells. Example 113 The apparatus described in Example 112, in which cultured cells simulate tissue. Example 114 The apparatus according to Example 112 or 113, wherein the cultured cells include skin cells, lung cells, or lung cells and skin cells. Example 115 The apparatus according to Example 114, wherein the cultured cells include lung cells. Example 116 The apparatus according to Example 115, further comprising cultured liver cells. Example 117 The apparatus according to Example 115, wherein cultured liver cells are in contact with cultured lung cells. Example 118 The apparatus described in Example 115, wherein cultured liver cells are isolated from cultured lung cells. Example 119 The apparatus according to Example 118, further comprising a microfluidic circulation system for circulating fluid between separated cells. Example 120 The apparatus according to any one of Examples 99 to 119, wherein the introduction system is configured to directly introduce the test contaminant into the test chamber. Example 121 The apparatus according to any one of Examples 99 to 120, wherein the introduction system includes an aerosol generator. Example 122 The apparatus according to Example 121, wherein the aerosol generator includes a nebulizer. Example 123 The apparatus according to any one of Examples 99 to 122, wherein the test chamber is electrically grounded. Example 124 The apparatus according to any one of Examples 99 to 123, comprising a vacuum pump configured to generate negative pressure relative to the pressure inside the test chamber and to flow air out of the test chamber through a passage and through an outlet. Example 125 The apparatus according to Example 124, wherein the airflow device includes a valve configured to control the flow of air from the test chamber to the vacuum pump. Example 126 The apparatus according to Example 125, wherein the airflow device comprises a flow meter, a transducer for measuring atmospheric pressure, or a flow meter and a transducer. Example 127 The apparatus according to Embodiment 126, wherein the airflow device comprises a flow meter, a transducer, or a flow controller operably coupled to a flow meter and transducer, and the flow controller is operably coupled to a vacuum pump to regulate the airflow through the system based on inputs from the flow meter, transducer, or flow meter and transducer. Example 128 A method for evaluating a filter medium of a test substance, comprising: (i) positioning a test substance in a test chamber having an inlet and an outlet such that air flowing from the inlet to the outlet flows through the filter medium of the test substance, and air flowing from the outlet to the inlet flows through the filter medium of the test substance; (ii) introducing a test contaminant into the test chamber such that the test contaminant is mixed into the air flowing from the inlet to the outlet; (iii) causing air to flow out of the test chamber through the filter medium and out the outlet; and (iv) simulating the mode of respiration, simulating the mode of the external environment, or simulating the mode of respiration and the mode of the external environment. Example 129 The method according to Example 128, wherein simulating the breathing pattern involves flowing air from a test chamber through a filter medium and through an outlet at the rate, volume, duration, or frequency of human inhalation. Example 130 The method according to Example 129, wherein 0.2 to 6 liters, preferably 0.5 to 3 liters, of air is flowed from the test chamber through a filter medium and through an outlet for a period of time from 0.5 to 15 seconds, preferably 1 to 6 seconds. Example 131 The method according to Example 129 or 130, comprising monitoring the velocity of the airflow from the test chamber through the filter medium and outlet, and adjusting the flow rate to maintain a desired velocity. Example 132 The method according to any one of Examples 128 to 131, wherein simulating the breathing pattern includes flowing air from an outlet through a filter medium into a test chamber. Example 133 The method according to Example 132, wherein simulating the breathing pattern involves alternating between letting air flow from the test chamber through a filter medium and out the outlet, and letting air flow from the outlet through the filter medium and into the test chamber. Example 134 The method according to Example 132 or 133, wherein simulating the breathing pattern involves flowing air from an outlet through a filter medium into a test chamber at the rate, volume, duration, or cycle of human inhalation. Example 135 The method according to Example 134, wherein 0.2 to 6 liters, preferably 0.5 to 3 liters, of air is flowed from the outlet through a filter medium into the test chamber for a period of 0.5 to 15 seconds, preferably 1 to 6 seconds. Example 136 The method according to any one of Examples 132 to 135, comprising monitoring the velocity of the airflow from the outlet through the filter medium into the test chamber and adjusting the flow rate to maintain a desired velocity. Example 137 The method according to any one of Examples 132 to 136, wherein simulating the breathing pattern includes ensuring that the air flowing from the outlet through the filter medium into the test chamber has a controlled humidity. Example 138 The method according to Example 137, comprising monitoring the relative humidity of the air flowing from the outlet through a filter medium into the test chamber, and adjusting the relative humidity of the air to maintain a controlled humidity. Example 139 The method according to Example 137 or 138, wherein simulating the breathing pattern includes ensuring that the air flowing from the outlet through the filter medium into the test chamber has a relative humidity in the range of 70 percent to 100 percent. Example 140 The method according to any one of Examples 132 to 139, wherein simulating the breathing pattern includes ensuring that the air flowing from the outlet through the filter medium into the test chamber has a controlled temperature. Example 141 The method according to Example 140, comprising monitoring the temperature of the air entering the test chamber from the outlet through a filter medium and adjusting the air temperature to maintain a controlled temperature. Example 142 The method according to Example 140 or 141, wherein simulating the breathing pattern involves ensuring that the air flowing from the outlet through the filter medium into the test chamber has a temperature in the range of 28 to 40 degrees Celsius, preferably 30 to 38 degrees Celsius, when it is in the passage. Example 143 The method according to any one of Examples 132 to 142, wherein simulating the respiration pattern includes ensuring that the air flowing from the outlet through the filter medium into the test chamber has a controlled carbon dioxide concentration. Example 144 The method according to Example 143, comprising monitoring the carbon dioxide concentration of the air entering the test chamber from the outlet through a filter medium, and adjusting the carbon dioxide concentration of the air to maintain a controlled carbon dioxide concentration. Example 145 The method according to Example 143 or 144, wherein simulating the breathing pattern involves ensuring that the air flowing from the outlet through the filter medium into the test chamber has a carbon dioxide concentration of 2% to 7% by volume, preferably 4% to 5% by volume. Example 146 The method according to any one of Examples 132 to 145, wherein simulating the respiration pattern includes ensuring that the air flowing from the outlet through the filter medium into the test chamber has a controlled pH. Example 147 The method according to Example 146, comprising monitoring the pH of the air entering the test chamber through a filter medium from the outlet and adjusting the pH of the air to maintain a controlled pH. Example 148 The method according to Example 146 or 147, wherein simulating the respiration pattern involves ensuring that the air flowing from the outlet through the filter medium into the test chamber has a pH of 8.0 to 8.3, preferably 8.1 to 8.2. Example 149 The method according to any one of Examples 128 to 148, wherein simulating the external environment includes ensuring that temperature-controlled air enters the test chamber through an inlet. Example 150 The method according to Example 149, comprising monitoring the temperature of the air entering the test chamber through the inlet and adjusting the air temperature to maintain a controlled temperature. Example 151 The method according to Example 150, wherein adjusting the temperature of the air includes heating the air or cooling the air. Example 152 The method according to any one of Examples 108 to 131, wherein simulating the characteristics of the external environment includes ensuring that the air flowing from the outlet through the filter medium into the test chamber has a controlled humidity. Example 153 The method according to Example 152, comprising monitoring the relative humidity of the air entering the test chamber from the outlet through a filter medium, and adjusting the relative humidity of the air to maintain a controlled humidity. Example 154 The method according to Example 153, wherein adjusting the relative humidity of the air includes increasing or decreasing the relative humidity of the air. Example 155 The method according to any one of Examples 128 to 154, wherein simulating the external environment includes passing ultraviolet light into the interior of the test chamber. Example 156 The method according to Example 155, comprising monitoring the intensity, spectral output, or intensity and spectral output of ultraviolet light in a test chamber, and adjusting the intensity, spectral output, or intensity and spectral output to maintain a desired intensity, spectral output, or intensity and spectral output. Example 157 The method according to any one of Examples 128 to 156, wherein simulating the characteristics of the external environment includes introducing environmental air pollutants into a test chamber. Example 158 The method according to Example 157, comprising monitoring the concentration of ambient air pollutants introduced into a chamber and adjusting the amount of ambient air pollutants introduced into the chamber to maintain a desired concentration of ambient air pollutants. Example 159 The method according to any one of Examples 128 to 158, comprising collecting test contaminants after air from a test chamber has passed through a filter medium. Example 160 The method according to Example 159, comprising determining the amount of collected test contaminants. Example 161 The method according to Example 159 or 160, wherein the test contaminant contains a pathogen. Example 162 The method according to Example 161, comprising determining the survival rate of a pathogen. Example 163 The method according to Example 162, including determining the pathogenicity of a pathogen. Example 164 The method according to any one of Examples 128 to 163, comprising bringing air flowed from a test chamber through a filter medium into contact with cultured cells. Example 165 The method according to Example 164, wherein cultured cells simulate tissue. Example 166 The method according to Example 164 or 165, wherein the cultured cells include skin cells, lung cells, or lung cells and skin cells. Example 167 The method according to Example 166, wherein the cultured cells include lung cells. Example 168 The method according to Example 167, further comprising cultured liver cells. Example 169 The method according to Example 167, wherein cultured liver cells are in contact with cultured lung cells. Example 170 The apparatus described in Example 167, wherein cultured liver cells are isolated from cultured lung cells. Example 171 The method according to Example 170, further comprising circulating a fluid between separated cells. Example 172 The method according to any one of Examples 128 to 171, wherein introducing the test contaminant into the test chamber includes introducing the test contaminant into the chamber as an aerosol. Example 173 The method according to Example 172, wherein the aerosol contains a mist. Example 174 A method for evaluating a filter medium of a test substance, comprising: (i) positioning a test substance in a test chamber having an inlet and an outlet such that air flowing from the inlet to the outlet flows through the filter medium of the test substance, and air flowing from the outlet to the inlet flows through the filter medium of the test substance; (ii) introducing a test contaminant into the test chamber such that the test contaminant is mixed into the air flowing from the inlet to the outlet; (iii) allowing air to flow from the test chamber through the filter medium and out the outlet; and (iv) collecting the test contaminant after the air from the test chamber has passed through the filter medium. Example 175 The method according to Example 174, comprising determining the amount of collected test contaminants. Example 176 The method according to Example 174 or 175, wherein the test contaminant contains a pathogen. Example 177 The method according to Example 176, comprising determining the survival rate of a pathogen. Example 178 The method according to Example 177, including determining the pathogenicity of a pathogen. Example 179 The method according to any one of Examples 174 to 178, comprising bringing air flowing from a test chamber through a filter medium into contact with cultured cells. Example 180 The method according to Example 179, wherein cultured cells simulate tissue. Example 181 The method according to Example 179 or 180, wherein the cultured cells include skin cells, lung cells, or lung cells and skin cells. Example 182 The method according to Example 181, wherein the cultured cells include lung cells. Example 183 The method according to Example 182, further comprising cultured liver cells. Example 184 The method according to Example 183, wherein cultured liver cells are in contact with cultured lung cells. Example 185 The apparatus described in Example 183, wherein cultured liver cells are isolated from cultured lung cells. Example 186 The method according to Example 185, further comprising circulating a fluid between separated cells. Example 187 The method according to any one of Examples 174 to 186, wherein introducing the test contaminant into the test chamber includes introducing the test contaminant into the chamber as an aerosol. Example 188 The method according to Example 187, wherein the aerosol contains a mist.

[0164] Here, we will further describe the examples with reference to the figures. [Brief explanation of the drawing]

[0165] [Figure 1] Figure 1 is a schematic perspective view of the test chamber. [Figure 2] Figure 2 is a block diagram of an apparatus for evaluating the filter medium of the test substance. [Figure 3] Figure 3 is a schematic cross-sectional view of an apparatus having a test contaminant inlet tube and a guide. [Figure 4] Figure 4 is a schematic cross-sectional view of a support and a test contaminant collector. [Figure 5] Figure 5 is a schematic cross-sectional view of a support and a test contaminant collector showing some of the components shown in Figure 4. [Figure 6] Figure 6 is a schematic cross-sectional view of a test contaminant collector. [Figure 7] Figure 7 is a schematic perspective view of a test contaminant collector. [Figure 8] Figure 8 is a schematic cross-sectional view of a test contaminant collector. [Figure 9] Figure 9 is a block diagram of some components of an air flow device and a respiratory condition simulation system. [Figure 10] Figure 10 is a block diagram of some components of an air flow device and a respiratory condition simulation system. [Figure 11] Figure 11 is a block diagram of some components of an apparatus including a respiratory humidifier system. [Figure 12] Figure 12 is a block diagram of some components of an apparatus including a respiratory temperature control system. [Figure 13] Figure 13 is a block diagram of some components of an apparatus including a carbon dioxide control system. [[ID=3�]] [Figure 14] Figure 14 is a block diagram of some components of an apparatus including a pH control system. [Figure 15] Figure 15 is a block diagram of some components of an external system temperature control system. [Figure 16] Figure 16 is a block diagram of some components of an external system humidity control system. [Figure 17] Figure 17 is a block diagram of some components of an external system UV light control system. [Figure 18] Figure 18 is a block diagram of some components of an environmental air contaminant control system. [Modes for carrying out the invention]

[0166] Figure 1 illustrates an example of a test chamber 100. The test chamber includes an inlet 110, an outlet 120, and an inlet opening 130. If the outlet is coupled to a negative pressure source or pump, air may flow into the test chamber 100 through the inlet. A device for introducing an aerosol can be operably coupled to the inlet opening 130 to introduce an aerosol into the test chamber. The introduced aerosol may be mixed with the air flowing from the inlet 110 through the test chamber 100 and out the outlet 120.

[0167] Figure 2 shows an embodiment of the apparatus 900 for evaluating the filter medium of a test substance. The apparatus 900 comprises a test chamber 100, such as the test chamber 100 in Figure 1, an introduction system 200, a support 300, an airflow device 400, a breathing condition simulation system 500, and an external environment simulation system 600. The introduction system 200 includes an aerosol generator mounted on the test chamber 100 and configured to introduce an aerosol containing the test contaminant into the test chamber 100. The support 300 is configured to define a passage communicating with the inside of the test chamber 100 and the outlet of the test chamber (such as the outlet 120 shown in Figure 1). The support 300 is configured to hold the test substance so that air passing from the test chamber 100 through the passage and outlet passes through the filter medium of the test substance.

[0168] The airflow device 400 is configured to draw air from the test chamber 100 through the passages and outlets of the support 300 and to push the air into the test chamber 100 through the outlet of the test chamber 100 and the passages of the support 300. The test chamber 100 may be provided with filtered vents (not shown) that allow the air pushed into the test chamber 100 from the airflow device 400 to escape from the inside of the test chamber 100.

[0169] The respiratory condition simulation system 500 can control and cooperate with the airflow device 400, or control and cooperate with it, to simulate one or more aspects of respiration, such as airflow velocity, volume, duration, and periodicity, humidity, temperature, pH, and carbon dioxide concentration.

[0170] The environmental simulation system 600, or components of the environmental simulation system 600, may be operably coupled to an inlet to control the contents of the air entering the inlet of the test chamber 100 (e.g., inlet 110 in Figure 1). The environmental simulation system 600 includes a valve 610 operably coupled to the inlet of the test chamber. The valve 610 may be a check valve that allows air to flow from outside the test chamber 100 into the test chamber 100, but prevents air from flowing from inside the test chamber 100 to outside the test chamber 100. The valve 610 may also be a dilution valve for introducing a controlled amount of environmental air pollutants into the test chamber 100.

[0171] Figure 3 shows an example of some components of a apparatus having a test contaminant inlet pipe 2000 and a guide 2100. The dashed line shows the airflow from the inlet 110 of the test chamber 100, through the guide 2100 and the passage 320 of the support 300, and out of the outlet 120 of the test chamber 100. The first end 2102 of the guide 2100 is sealed to the upper surface 150 of the test chamber 100, which has an inlet opening 130. The second end 2104 of the guide is sealed to the surface of the support 300. The guide 2100 has an axially positioned guide inlet 2106 that allows air flowing through the inlet 110 of the test chamber 100 to flow out of the outlet 120 of the test chamber 100 through the passage 320 of the support 300 into the internal volume of the guide 2100. The test contaminant inlet pipe 2000 surrounds the inlet opening 130 and extends into the guide 2100 beyond the guide inlet 2106. The aerosol 2200 containing the test contaminant is introduced by the introduction system 200 through the introduction opening 130 and the test contaminant inlet tube 2000, flowing into the guide 2100, which directs the aerosol 2200 containing the test contaminant towards the passage 320 of the support 300. The air flowing through the guide inlet 2106 (shown by the dashed line) introduces more layered layers and flows along the outer surface of the test contaminant inlet tube 2000 with less turbulence of air. As the air flows toward the second end 2104 of the guide 2100, at least a portion of the layered state-like state of the airflow is maintained, which reduces the interaction of the aerosol 2200 with the inner surface of the guide 2100. This reduces the loss of the test contaminant due to sorption, which may improve the accuracy, reliability, or precision and reliability of the experiment or the apparatus.

[0172] Figures 4–8 show examples of a support 300 and a test contaminant collector 700. The support 300 comprises a housing 310 which can be attached to the test chamber around an outlet (such as outlet 120 in Figure 1) using bolts 311. The support 300 comprises an insert 360 configured to be inserted through the outlet of the test chamber. The insert 360 is configured to reversibly couple to the housing 310, for example, via a screw engagement or a torsion and lock engagement. An O-ring 365 may facilitate sealing between the housing 310 and the insert 360.

[0173] The housing 310 and the insert 360 together define a passage 320 through the support 300. Air from the test chamber may flow through the outlet and through the passage 320. The insert 360 is equipped with a coupling 380 for connecting to an airflow device, which can draw air from the test chamber through the passage 320, by connecting to a conduit 410 such as a pipe.

[0174] The support 300 includes a retaining assembly 350 which can be attached to the housing 310 by bolts 351. The retaining assembly 350 holds the test substance 999 containing a filter medium so that air passes through the filter medium as air flows out of the test chamber through the passage 320. The retaining assembly 350 includes a clamping disc 355 with an opening through which the bolts 351 extend, an upper test substance sealing disc 330, a lower test substance sealing disc 335, a height adjustment disc 340, and an O-ring sealing disc 333. The test substance 999 may be placed on the lower test substance sealing disc 335, the height adjustment disc 340 may be placed on the test substance 999, the upper test substance sealing disc 330 may be placed on the height adjustment disc 340, the clamping disc 355 may be placed on the upper test substance sealing disc 330, and the assembly may be bolted to the housing 310 by bolts 351 to hold the test substance 999.

[0175] The handle 370 is coupled to the insert 360 to facilitate gripping and twisting of the insert 360 for engaging or disengaging the insert 360 from the housing 310. The insert 360 may be removed through the exit of the test chamber (e.g., exit 120 in Figure 1). The test contaminant collector 700 is held on the insert 360. When the insert 360 is removed through the exit of the test chamber, the test contaminant collector 700 is also removed. Thus, the test contaminant collector 700 can be removed from the test chamber without accessing the inside of the test chamber.

[0176] The test contaminant collector 700 includes a cup 710 and a holder 730. The holder 730 is equipped with a receptacle 737 for receiving and holding the cup 710. A material 720 configured to capture the test contaminant is placed inside the cup 710. The material 720 may include a hydrogel when the test contaminant includes biological material such as a virus. A funnel element 800, such as a cascade impactor ring, directs air flowing through the passage 320 toward the material 720 so that the air collides with the material 720. After the air collides with the material 720, the air may flow through a lateral opening 735 of the holder 730 so that the air continues to flow through the passage 320 and exits the test chamber.

[0177] Figure 9 shows some components of an example of an airflow device and a breathing condition simulation system. The airflow device includes a piston pump 420, which includes a piston 425. The pump 420 is operably connected to a conduit 410 connected to an insert in a support (for example, as shown in Figure 8), and the movement of the piston 425 causes air to be drawn from the test chamber through the passage in the support into the conduit 410, or introduced into the test chamber through the conduit 410 and the passage in the support, depending on the direction in which the piston 425 moves.

[0178] The piston 425 is operably coupled to a motor 430. The motor 430 may be configured to provide linear motion or rotational motion. If the motor 430 provides rotational motion, it may include a motion converter 435 for converting rotational motion to linear motion. The motor 435 includes a coder 437 for controlling the motor. The coder 437 is operably coupled to an action controller 510 that provides commands to the motor 430 to move the piston 425 in a manner that simulates one or more aspects of inhalation or exhalation, such as speed, volume, duration, and periodicity. The action controller 510 may be operably coupled to a system controller 1000, which may be operably coupled to a user interface.

[0179] Figure 10 shows some components of an embodiment of an airflow device and breathing condition simulation system. The airflow device comprises a positive pressure pump 450, a vacuum pump 460, a first valve 442, a second valve 444, and a differential flow controller 440, all coupled to a conduit 410 coupled to an insert in a support (for example, as shown in Figure 8). A controller 520 may be operably coupled to the first valve 442, the second valve 444, and the differential flow controller 440, and may also be operably coupled to the positive pressure pump 450 and the vacuum pump 460. Based on input from the differential flow controller 440, the controller 520 can open and close the first valve 442 and the second valve 444, causing air to flow from the positive pressure pump 450 through the conduit 410 into the passages of the support and the test chamber, or from the test chamber through the passages of the support and through the conduit towards the vacuum pump 460. The controller 520 may be operably coupled to a system controller 1000, which may be operably coupled to a user interface.

[0180] Figure 11 shows an example of a device comprising a respiratory humidifier system. The device includes a humidifier 570, which is positioned and configured to humidify air flowing from an airflow device through a conduit 410 and through a passage in a support 300 into the test chamber 100. A humidity sensor 572 is located in the passage of the support 300. The humidity sensor 572 is operably coupled to a humidity controller 574, which is operably coupled to the humidifier 570. The controller 574 increases or decreases the humidity of the air in the humidifier 570 based on input from the sensor 572. The humidity controller 574 may be operably coupled to a system controller 1000, which can be operably coupled to a user interface.

[0181] Figure 12 shows an example of a device comprising a respiratory temperature control system. The system is configured to control the temperature of the air in a passage of a support 300 so that the air flowing from the passage to the test chamber 100 is temperature-controlled. The system includes a heater 560 configured to heat the air in the passage, a temperature sensor 562 configured to detect the temperature in the passage, and a temperature controller 564 operably coupled to the temperature sensor 562 and the heater 560. The temperature controller 562 is configured to control the heater 560 to adjust the temperature of the air based on input from the temperature sensor 562. The temperature controller 564 may be operably coupled to a system controller 1000 which can be operably coupled to a user interface.

[0182] FIG. 13 shows an example of an apparatus comprising a carbon dioxide control system. The system includes a source of pressurized 100% carbon dioxide 550 operably coupled to a first valve 552, a positive pressure pump 450 operably coupled to a second valve 554, and an in-line mixer 559 upstream of valves 552, 554. The system also includes a carbon dioxide sensor 558 upstream of the mixer 559, and a carbon dioxide controller 556 operably coupled to the carbon dioxide sensor 558 and the first valve 552 and the second valve 554. The controller 556 is configured to open and close the first valve 552 and the second valve 554 based on input from the sensor 558 to maintain a desired carbon dioxide concentration in the air flowing through the passage of the support and into the test chamber through conduit 410. The carbon dioxide controller 556 may be operably coupled to a system controller 1000 that may be operably coupled to a user interface.

[0183] FIG. 14 shows an example of an apparatus comprising a pH control system. The system includes a humidifier 570 having a reservoir containing water, a mixer 586 in the reservoir of the humidifier 570, an acid pump 582 coupled to an acid source 581 and configured to pump acid from the acid source 581 into the reservoir of the humidifier 470. The system also includes a base pump 584 coupled to a base source 583 and configured to pump base into the reservoir of the humidifier 470 from the base source 583, a pH sensor 588 upstream of the reservoir 570, and a pH controller 580. The pH controller 580 is operably coupled to the pH sensor 588, the acid pump 582, the base pump 584, and the mixer 586. The pH controller 580 is configured to pump acid or base into the reservoir of the humidifier 570 and activate the mixer 586 based on input from the pH sensor 588 to either the acid pump 582 or the base pump 584. The pH controller 580 may be operably coupled to a system controller 1000 that may be operably coupled to a user interface.

[0184] Figure 15 shows an example of some components of an external environment simulation system having a temperature control system. The temperature control system includes a temperature control unit 620 operably coupled to a valve 610 operably coupled to the inlet of a test chamber 100. The temperature control unit 620 may include a heater, a cooler, or a heater and a cooler. The system includes a temperature sensor 624 positioned and configured to measure the temperature of the air entering the test chamber 100 through the inlet. The temperature sensor 624 is operably coupled to a temperature controller 622, which is operably coupled to the temperature control unit 620. The temperature controller 622 is configured to adjust the temperature of the air entering the test chamber based on the input from the temperature sensor 624. The temperature controller 622 may be operably coupled to a system controller 1000, which may be operably coupled to a user interface.

[0185] Figure 16 shows an example of some components of an external environment simulation system having a humidity control system. The humidity control system includes a humidity control unit 630 operably coupled to a valve 610 operably coupled to the inlet of the test chamber 100. The humidity control unit 630 may include a humidifier, a dehumidifier, or a humidifier and a dehumidifier. The system includes a humidity sensor 634 positioned and configured to measure the humidity of the air entering the test chamber 100 through the inlet. The humidity sensor 634 is operably coupled to a humidity controller 632, which is operably coupled to the humidity control unit 630. The humidity controller 632 is configured to adjust the humidity of the air entering the test chamber based on input from the humidity sensor 634 to the humidity control unit 630. The humidity controller 632 may be operably coupled to a system controller 1000, which may be operably coupled to a user interface.

[0186] Figure 17 shows an example of some components of an external environment simulation system having a UV light control system. The UV light control system includes a UV light source 640 located outside the test chamber 100. The test chamber 100 or a portion of the test chamber 100 is UV transparent so as to allow UV light from the light source to pass through the interior of the test chamber 100. The UV source 640 may be located above the test contaminant introducer 200. The UV system includes a UV sensor 644 and a UV controller 642 located inside the test chamber 100. The UV sensor 644 may detect UV light intensity, wavelength, or intensity and wavelength. The UV controller 642 is operably coupled to the UV light source 640 and the UV sensor 644 and is configured to cause the UV light source to adjust its intensity, spectral output, or intensity and spectral output based on input from the UV sensor 644. The UV controller 642 may be operably coupled to a system controller 1000 which can be operably coupled to a user interface.

[0187] Figure 18 shows an example of some components of an environmental air pollutant control system. The system includes a pollutant introducer 650, which may be equipped with an aerosol generator such as a nebulizer. The pollutant introducer 650 is operably coupled to a dilution valve 611, which can control the amount of pollutant entering the inlet of the test chamber 100. The system includes a pollutant sensor 654, which is positioned and configured to detect the amount of environmental pollutant entering the test chamber 100 through the inlet. The system includes a pollutant controller 652, which is operably coupled to the pollutant introducer 650, the dilution valve 611, and the pollutant sensor 654. The pollutant controller 650 controls the pollutant introducer 650 and the dilution valve 611 to control the amount of pollutant entering the test chamber through the inlet based on input from the pollutant sensor 654. The pollutant controller 652 may be operably coupled to a system controller 1000, which can be operably coupled to a user interface.

[0188] It will be understood that one or more of the systems shown in Figures 9-18 may be included in the test apparatus described in this disclosure.

[0189] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers representing amounts, quantities, percentages, etc., should be understood in all cases as being modified by the term “approximately.” Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges therewith, which may or may not be specifically listed herein. Thus, in this context, number A is understood as A ± 2%. In this context, number A may be considered to include a number that falls within the general standard error of the measurement of the characteristic that number A modifies. Number A may deviate by the percentages listed above, provided that in some cases, such as those used in the appended claims, the amount by which A deviates does not substantially affect the fundamental and novel characteristic of the claimed invention. Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges therewith, which may or may not be specifically listed herein.

Claims

1. A device for evaluating the filter medium of a test substance, The test chamber includes an introduction opening, an inlet, and an outlet on the surface of the test chamber, An introduction system configured to introduce the test contaminant into the test chamber through the introduction opening such that the test contaminant is mixed into the air flowing from the inlet to the outlet, A support configured to hold the test substance, wherein the support defines the passage downstream of the test substance's location such that air flowing from the inlet to the outlet passes through the filter medium before entering the passage, An airflow device configured to draw air from inside the test chamber through the aforementioned passage and the aforementioned outlet, and to introduce air into the test chamber through the aforementioned outlet and the aforementioned passage, The test contaminant collector is positioned within the airflow path in the passage such that the air drawn in from the test chamber through the passage comes into contact with the test contaminant collector, An apparatus comprising: a respiratory condition simulation system configured to simulate the manner of respiration; an external environment simulation system configured to simulate the manner of the external environment; or both the respiratory condition simulation system and the external environment simulation system.

2. The apparatus according to claim 1, further comprising a guide having an inner surface for directing airflow from the introduction opening toward the passage of the support.

3. The apparatus according to claim 2, comprising a test contaminant inlet pipe surrounding the introduction opening and extending from the surface of the test chamber into the internal volume of the guide.

4. The apparatus according to claim 2 or 3, wherein the guide has a first end and a second end, the first end being sealed to the surface of the test chamber around the introduction opening, and the second end being sealed to the surface of the support.

5. The apparatus according to claim 4, wherein the guide is provided with a guide air inlet adjacent to the first end of the guide.

6. The apparatus according to claim 3, wherein the guide has a first end and a second end, the guide is provided with a guide air inlet adjacent to the first end of the guide, and the test contaminant inlet pipe extends beyond the guide air inlet into the internal volume of the guide toward the second end of the guide.

7. The apparatus according to any one of claims 1 to 6, wherein the respiratory condition simulation system comprises an airflow device controller operably coupled to the airflow device, and the airflow device controller is configured to cause the airflow device to alternately draw air from the test chamber through the passage and the outlet and introduce air into the test chamber through the outlet and the passage.

8. The apparatus according to any one of claims 1 to 7, wherein the respiratory condition simulation system comprises a humidifier, the humidifier being operably coupled to the airflow device, and the air introduced into the test chamber through the outlet and the passage having a controlled humidity.

9. The apparatus according to any one of claims 1 to 8, wherein the respiratory condition simulation system comprises a heating system configured such that the air introduced into the test chamber by the airflow device through the outlet and the passage has a controlled temperature when it is in the passage.

10. The apparatus according to any one of claims 1 to 9, wherein the respiratory condition simulation system comprises a carbon dioxide concentration controller system configured to introduce carbon dioxide into the air introduced into the test chamber through the outlet and the passage, so that the proportion of carbon dioxide in the air in the passage can be adjusted to a desired range.

11. The apparatus according to any one of claims 1 to 10, wherein the respiratory condition simulation system comprises a pH controller system, the pH controller system comprising a pH controller device configured to control the pH of air caused by the airflow device introduced into the test chamber through the outlet and the passage.

12. The apparatus according to any one of claims 1 to 11, wherein the apparatus comprises the external environment simulation system, the external environment simulation system comprising one or more of the following: an external temperature control system configured to allow temperature-controlled air to enter the test chamber through the inlet; an external humidity control system configured to allow humidity-controlled air to enter the test chamber through the inlet; and an ultraviolet light source configured to allow ultraviolet light to pass through the interior of the test chamber.

13. The apparatus according to claim 12, wherein the external environment simulation system comprises a dilution valve operably coupled to the inlet, and the dilution valve is configured to introduce environmental air pollutants into the test chamber through the inlet.

14. The apparatus according to any one of claims 1 to 13, wherein the test chamber is electrically grounded.

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