FILTER ASSEMBLY FOR THERAPEUTIC GAS DELIVERY DEVICES - Patent application

Abstract

Disclosed herein is a sample gas filter assembly (100) for a therapeutic gas delivery device. The filter assembly includes: a filter device (106) comprising an inlet (102), an outlet (124), at least one reservoir (118), and at least one filter membrane (316) between the inlet and outlet, the filter device operable to remove water vapor from the sample gas and collect condensate in the at least one reservoir; a water-permeable tubular membrane (300) fluidly connected to the outlet of the filter device; and a vent cap (114) connected to the filter device and surrounding the outlet, the vent cap comprising a vent opening (116). The sample gas filter assembly is configured to maintain condensate pH from an assembly for humidifying and filtering a sample gas in a therapeutic gas delivery device.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to a patient sample gas filter assembly and methods of use thereof. More particularly, the present disclosure relates to a patient sample gas filter assembly that includes a filtration system for filtering liquid from a gas sample in a therapeutic gas delivery system. [Background technology]

[0002] Therapeutic gases can be delivered to a patient through the inspired respiratory gas flowing from a breathing circuit associated with a ventilator. For example, the therapeutic gas can be injected into the inspired respiratory gas flowing through the breathing circuit and then delivered to the patient's airways. One such therapeutic gas is nitric oxide, which can have a vasodilatory effect on the patient.

[0003] During therapeutic gas administration, a gas sensor module can monitor a portion of the inspired respiratory gas to ensure that the therapeutic gas is being delivered at the desired dose in the inspired respiratory gas stream. For example, a patient gas sample line and sample gas filter assembly can be used to provide the sample gas (e.g., a portion of the inspired respiratory gas stream) to a gas sensor module that monitors the concentration of the therapeutic gas being delivered to the patient. In some cases, the breathing circuit that delivers the therapeutic gas to the patient's airway can be humidified. Traditionally, patient gas sample lines and sample gas filter assemblies have included complex designs to separate liquids from the sample gas. However, these designs can be difficult to manufacture and require the patient gas sample line and sample gas filter assembly to be in a specific orientation during use. Furthermore, these designs can allow wicking during various stages of filtration, which can cause premature blockage. Traditionally, permeable tubing has been used to filter moisture from the sample gas before it enters the filter. However, the permeable tubing can react with saline in the sample gas to produce hydrochloric acid, which corrodes the sampling sensor and other components, requiring replacement of the components well before their desired lifespan. Additionally, the saline in the sample gas can react with the permeable tubing, causing blockages within the permeable tubing.

[0004] Therefore, there is a need for a patient gas sample line and sample gas filter assembly that is easier to manufacture, more convenient to use, and longer lasting. Summary of the Invention [Means for solving the problem]

[0005] An embodiment of the present disclosure includes an assembly for a therapeutic gas delivery device. The assembly may include a filter apparatus, a water-permeable tubular membrane, and a vent cap. The filter apparatus may have an inlet, an outlet, at least one reservoir, and at least one filter membrane. The filter membrane may be located between the inlet and the outlet. The filter apparatus may be operable to remove water vapor from the sample gas and collect condensate in the at least one reservoir. The water-permeable tubular membrane may be fluidly connected to the outlet of the filter apparatus. The vent cap may be connected to the filter apparatus and surround the outlet. The vent cap may have a vent opening.

[0006] In certain cases, the water-permeable tubular membrane can be configured to humidify the sample gas.

[0007] In certain cases, the vent cap can have multiple vent openings. In certain cases, the vent cap is configured to receive and secure a water-permeable tubular membrane.

[0008] In certain cases, the water-permeable tubular membrane is formed from a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer. In certain cases, the water-permeable tubular membrane is a tubing comprising a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer.

[0009] An embodiment of the present disclosure includes a filter apparatus for a therapeutic gas delivery device. The filter apparatus can have a housing, a first chamber, and a second chamber. The housing can include a sample gas inlet and a sample gas outlet. The sample gas inlet can be operable to receive a gas sample from a sample line connected to an inspiratory line of the therapeutic gas delivery device. The first chamber can be located within the housing and can have a first filter membrane and a first reservoir located between the sample gas inlet and the first filter membrane. The second chamber can be located within the housing and can have a second filter membrane and a second reservoir located between the first filter membrane and the sample gas outlet.

[0010] In certain cases, the first and second reservoirs are axially oriented such that the filter device can be operable for use in any axial direction. In certain cases, the housing, each of the chambers, and each of the filter membranes can have a substantially circular cross-section.

[0011] In certain cases, the at least one reservoir can be large enough to contain water for 12 hours of continuous use. In certain cases, the at least one reservoir can have a volume of at least 10 cubic centimeters. In certain cases, the assembly can be configured to be installed into the therapeutic gas delivery device with one hand.

[0012] Aspects of the present disclosure include a method for humidity-conditioning and filtering a sample gas in a therapeutic gas delivery device. The method can include passing the sample gas through a filter apparatus of an assembly, collecting condensate from the sample gas in the filter apparatus, and passing the filtered gas through a water-permeable tubular membrane of the assembly. The sample gas exiting the water-permeable tubular membrane can be humidity-conditioned sample gas.

[0013] In certain cases, the sample gas exiting the water-permeable tubular membrane can be a humidity-adjusted sample gas with a confidence level of at least 98%, at least 99%, at least 99.5%, at least 99.9%, or at least 99.95%.

[0014] In certain cases, the outer surface of the water-permeable tubular membrane may be exposed to ambient air flow.

[0015] In certain cases, the humidity-adjusted sample gas may be substantially free of saline. In certain cases, the production of hydrochloric acid (HCl) may be reduced or prevented within the therapeutic gas delivery device.

[0016] In certain cases, clogging of a sample line connected to the assembly, clogging of a pump connected to the sample line, corrosion of a filter device, and / or corrosion within the therapeutic gas device can be reduced or prevented with at least a 98% confidence level.

[0017] In certain cases, the assembly can maintain the condensate at a pH of about 5.0 to about 6.0, about 5.3 to about 5.6, or about 5.4 to about 5.6.

[0018] An embodiment of the present disclosure includes a method for maintaining a condensate pH from an assembly for humidifying and filtering a sample gas in a therapeutic gas delivery device. The method can include passing the sample gas through a filter apparatus of the assembly, collecting condensate from the sample gas in the filter apparatus, and passing the filtered sample gas through a water-permeable tubular membrane of the assembly. The sample gas exiting the water-permeable tubular membrane can be a humidity-conditioned sample gas. The assembly can maintain the condensate at a pH of about 5.0 to about 6.0.

[0019] In certain cases, the humidity-adjusted sample gas may be substantially free of saline. In certain cases, the outer surface of the water-permeable tubular membrane may be exposed to ambient airflow. In certain cases, the assembly may reduce or prevent the generation of HCl within the therapeutic gas delivery device.

[0020] In certain cases, the assembly can reduce or prevent clogging of a sample line connected to the assembly, clogging of a pump connected to a sample line, corrosion of a filter device, or corrosion of a therapeutic gas delivery device.

[0021] Aspects of the present disclosure include a method for preventing deterioration or corrosion in a therapeutic gas delivery device. The method may include passing a sample gas through a filter apparatus of an assembly, collecting condensate from the sample gas in the filter apparatus, passing the filtered sample gas through a water-permeable tubular membrane of the assembly, and preventing the sample gas from contacting a sensor without first being humidity-conditioned at a confidence level of at least 98%. The sample gas exiting the water-permeable tubular membrane may be humidity-conditioned sample gas.

[0022] An embodiment of the present disclosure includes a method for preventing deterioration or corrosion in a therapeutic gas delivery device. The method can include passing a sample gas through a filter apparatus of an assembly, collecting condensate from the sample gas in the filter apparatus, passing the filtered sample gas through a water-permeable tubular membrane of the assembly, and maintaining the condensate at a pH of about 5.0 to about 6.0 with at least a 98% confidence level. The sample gas exiting the water-permeable tubular membrane can be humidity-controlled sample gas.

[0023] The description will be more fully understood with reference to the following figures and data graphs, which are presented as various embodiments of the present disclosure and should not be construed as a complete recitation of the scope of the present disclosure. It should be noted that for clarity of illustration, certain elements in the various figures may not be drawn to scale. With the understanding that these figures merely depict exemplary embodiments of the present disclosure and therefore should not be considered limiting of its scope, the principles herein will be described and explained with additional specificity and detail through the use of the accompanying drawings. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a cross-sectional view of a sample gas filter assembly. [Figure 2] FIG. 2 is a cross-sectional view of the ventilation cap. [Figure 3] FIG. 1 is a cross-sectional view of a sample gas filter assembly. [Figure 4]FIG. 1 is a cross-sectional view of a sample gas filter assembly. [Figure 5] FIG. 1 is a perspective view of a sample gas filter assembly. [Figure 6] FIG. 1 is a cross-sectional view of a sample gas filter assembly. [Figure 7] 1 is a flowchart of an exemplary method. [Figure 8] 1 is a flowchart of an exemplary method. [Figure 9] 1 is a flowchart of an exemplary method. [Figure 10] 1 is a flowchart of an exemplary method. DETAILED DESCRIPTION OF THE INVENTION

[0025] It will be understood that for simplicity and clarity of description, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or similar elements. Additionally, numerous specific details have been set forth in order to provide a thorough understanding of the examples described herein. However, those skilled in the art will understand that the examples described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the relevant features being described. Additionally, the specification should not be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale, and the proportions of certain parts may be exaggerated to better illustrate the details and features of the present disclosure.

[0026] Several definitions that apply throughout the above disclosure are now presented.

[0027] The term "coupled," as used herein, is defined as directly or indirectly connected through intervening components, and is not necessarily limited to a physical connection. The connection may be such that the objects are permanently connected or releasably connected.

[0028] The term "substantially" is defined as essentially conforming to a particular size, shape or other term that varies substantially, and elements need not be precise.

[0029] The terms "comprising," "including," and "having" are used interchangeably in this disclosure. The terms "comprising," "including," and "having" mean including, but not necessarily limited to, what is stated.

[0030] The terms "filter" and "filtration" are used herein in their broadest sense to encompass any and all of the various types and degrees of removal or separation of liquid from gas, and in some cases may also include the removal of other non-liquid particulates, if present.

[0031] The term "liquid" is used herein in its broadest sense to encompass humidity, water vapor, moisture from humidified air, other liquids in the vapor state, atomized liquids, atomized medical solutions (e.g., saline), and suspensions.

[0032] The terms "humidify" and "humidifying" refer to adjusting the relative humidity of a gas (e.g., a sample gas) to match the humidity of the ambient air. Thus, if the sample gas has a lower relative humidity than the ambient air, moisture will flow into the sample gas, and if the sample gas has a higher relative humidity than the ambient air, moisture will flow out of the sample gas.

[0033] The present disclosure relates to a patient gas sample line and sample gas filter assembly and methods for their use. The filter includes a multi-stage filtration system with a liquid reservoir that filters liquid from a liquid-containing sample gas (e.g., a portion of a respiratory gas and therapeutic gas mixture). The liquid component may be any removable liquid, such as, for example, moisture, water vapor, water from humidified air, other liquids in a vapor state, nebulized liquids, nebulized medical solutions (e.g., saline solutions), and suspensions.

[0034] The sample gas filter assembly can be used with a therapeutic gas delivery system that delivers a therapeutic gas (e.g., nitric oxide) to a patient's airway. The therapeutic gas is delivered to the patient by administration to a breathing circuit, typically along with a mechanical ventilator. A subsystem of the therapeutic gas delivery system contains a gas sensor module that includes one or more gas sensors that monitor the concentration of the therapeutic gas and / or other gases delivered to the patient. The gas sensor module is connected to the same patient breathing circuit as the therapeutic gas delivery system.

[0035] The sample gas filter assembly may be more convenient to use than conventional patient gas sample lines and filters. For example, the sample gas filter assembly may be easier to manufacture (e.g., may involve only one or two manufacturing steps). Furthermore, the sample gas filter assembly may be used in any axial orientation.

[0036] Traditionally, sample gas filter assemblies are configured to receive sample gas from a patient's breathing circuit at a gas sample tee. The sample gas is then transported to the filter through a water-permeable tubular membrane. However, this configuration of the sample gas filter assembly—the water-permeable tubular membrane delivering the sample gas to the filter—poses problems with corrosion and blockage along the flow path and into the gas sensor module. When the sample gas enters the water-permeable tubular membrane before being filtered, the membrane can react with cations found in the sample gas, such as sodium found in saline. The water-permeable tubular membrane can contain sulfonic acid receptor sites in its polytetrafluoroethylene (PTFE) matrix. These sites can bind to any cation (e.g., sodium, found in saline and commonly used in therapeutic gases). When sodium in the sample gas binds to the water-permeable tubular membrane, chlorine is liberated and binds to hydrogen, producing hydrochloric acid. When hydrochloric acid is produced in the form of vapor, it may not be captured by the filter device and may flow into the gas sensor module, thereby corroding the sample sensor, sample pump, and other components in the therapeutic gas delivery device. Corrosion caused by hydrochloric acid may also occur in the filter device. Furthermore, when sodium cations in saline react with the water-permeable tubular membrane, accumulation may occur, potentially causing blockage of the water-permeable tubular membrane.

[0037] The present disclosure provides a novel solution to the problem of saline interaction with the water-permeable tubular membrane. By reconfiguring the sample gas filter assembly to filter the sample gas through a filter device before allowing the sample gas to flow through the water-permeable tubular membrane, sodium chloride can be filtered before contacting the water-permeable tubular membrane. By filtering the sodium chloride before it contacts the water-permeable tubular membrane, downstream corrosion and clogging problems are avoided.

[0038] 1 shows one example of a sample gas filter assembly 100. Sample gas filter assembly 100 can include a sample gas inlet 102, a sample gas outlet 124, an assembly outlet 104, a filter device 106 (e.g., a sample gas filter), a vent cap 114, and a water-permeable tubular membrane (not shown in FIG. 1).

[0039] Filter device 106 can include a housing 126 having a sample gas inlet 102 and a sample gas outlet 124. Sample gas inlet 102 can be in fluid communication with sample gas outlet 124, thereby establishing a fluid flow path through filter device 106 (e.g., from sample gas inlet 102 to sample gas outlet 124).

[0040] The sample gas inlet 102 can accept the sample gas into the filter apparatus 106. In one example, the sample gas inlet 102 can receive the sample gas from a first portion of a sample line connected to the inlet line of a therapeutic gas delivery device (e.g., via a gas sample tee). For example, the sample gas inlet 102 can be removably coupled to the sample line, and the sample line can be removably coupled to the inlet line at the sample gas tee, thereby establishing fluid communication between the inlet line and the filter apparatus 106. In another example, the sample gas line can be connected to the exhalation line of a therapeutic gas delivery system. In other examples, the sample gas line can be connected to any type of gas line in which it is desired to sample a gas or combination of gases to determine the concentration.

[0041] The sample gas outlet 124 can exhaust the sample gas from the filter device 106. The sample gas can then flow through the water-permeable tubular membrane, as described below. The sample gas can exit the sample gas filter assembly 100 at the assembly outlet 104, where it can be delivered to a gas sensor module in the therapy delivery device by a second portion of the sample line. The assembly outlet 104 can be configured to removably couple to a fitting (e.g., a Luer fitting). For example, in one case, the assembly outlet 104 can extend outward (e.g., away from) the sample gas filter assembly 100 and include external threads 122 for removably coupling to a fitting. In another example, the assembly outlet 104 can include internal threads for removably coupling to a fitting. The configuration (e.g., external or internal threads) of the assembly outlet 104 can be of the opposite gender to the connector of the first portion of the sample line (e.g., at the sample gas inlet 102), such that the sample gas filter assembly is unidirectional.

[0042] A sample gas pump can be used to pump sample gas through the sample gas filter assembly 100 and into the gas sensor module. The sample gas pump can generate a fluid flow of sample gas from the sample gas inlet 102 through the assembly outlet 104 and into the gas sensor module.

[0043] The first chamber 110 can be located within the housing 126. In other words, the housing 126 of the filter device 106 can define, in whole or in part, the first chamber 110. In one case, the first chamber 110 can have a substantially circular cross-section that can define the diameter of the first chamber 110. The first chamber 110 can include a first reservoir 118. The filter device 106 can remove liquid (e.g., moisture, water vapor, water from humidified air, other liquids in a vapor state, nebulized liquids, nebulized medical solutions and suspensions, etc.) from the sample gas (e.g., via a filter membrane, described in further detail below) and collect the liquid in the first reservoir 118. The first reservoir 118 can be axially oriented along the length of the filter so that the filter device 106 can operate (e.g., remove liquid from the sample gas and collect liquid) in any orientation during operation. The first reservoir 118 can define a volume and, in some cases, can be configured to contain liquid for approximately 12 hours of continuous use before needing to be replaced and / or emptied.

[0044] The volume of the first reservoir 118 can be about 5 cubic centimeters to about 10 cubic centimeters, about 10 cubic centimeters to about 15 cubic centimeters, about 15 cubic centimeters to about 20 cubic centimeters, about 20 cubic centimeters to about 25 cubic centimeters, about 25 cubic centimeters to about 30 cubic centimeters, about 30 cubic centimeters to about 35 cubic centimeters, about 35 cubic centimeters to about 40 cubic centimeters, or greater than about 40 cubic centimeters.

[0045] The second chamber 112 can be located within a housing 126. In other words, the housing 126 of the filter device 106 can fully or partially define the second chamber 112. In one case, the second chamber 112 can have a substantially circular cross-section, which can define the diameter of the second chamber 112. The second chamber 112 can include a second reservoir 120. The filter device 106 can remove liquid (e.g., moisture, water vapor, water from humidified air, other liquids in a vapor state, nebulized liquids, nebulized medical solutions and suspensions, etc.) from the sample gas (e.g., via a filter membrane, described in further detail below) and collect the liquid in the second reservoir 120. The second reservoir 120 can be axially oriented along the length of the filter so that the filter device 106 can operate (e.g., remove liquid from the sample gas and collect liquid) in any orientation during operation. The second reservoir 120 can define a volume and, in some cases, can be configured to contain liquid for approximately 12 hours of continuous use before needing to be replaced.

[0046] The second reservoir 120 can have a volume of about 1 cubic centimeter to about 5 cubic centimeters, about 5 cubic centimeters to about 10 cubic centimeters, about 10 cubic centimeters to about 15 cubic centimeters, about 15 cubic centimeters to about 20 cubic centimeters, or greater than about 20 cubic centimeters. In some examples, the second reservoir 120 can have a volume smaller than the volume of the first reservoir 118. In other examples, the second reservoir 120 can have a volume larger than the volume of the first reservoir 118. In some examples, the first reservoir 118 and the second reservoir 120 can have the same or substantially the same volume.

[0047] The sample gas filter assembly 100 can include a vent cap 114. The vent cap can have one or more vent openings 116. The vent openings can be rectangular in shape, as shown in FIG. 1. The vent openings 116 can have other shapes, as shown in FIGS. 3-6, for example. The vent openings 116 can have any shape that allows air to enter the vent cap 114. The vent cap 114 can be configured to receive and secure a water-permeable tubular membrane. For example, the vent cap 114 can have a water-permeable tubular membrane holder 108 for securing the water-permeable tubular membrane.

[0048] 2 shows one example of a vent cap 114. The sample gas filter assembly 100 can have a vent cap 114 with multiple vent openings 116. The gas filter assembly 100 can include a water-permeable tubular membrane inlet conduit 204, a water-permeable tubular membrane inlet port 200, a water-permeable tubular membrane outlet port 202, a sample gas outlet conduit 206, a sample gas outlet 124, and an assembly outlet 104.

[0049] A water-permeable tubular membrane (not shown in FIG. 2 ) can be connected to the water-permeable tubular membrane inlet port 200 and the water-permeable tubular membrane outlet port 202, thereby establishing a fluid flow path between the water-permeable tubular membrane inlet port 200 and the water-permeable tubular membrane outlet port 202. A water-permeable tubular membrane inlet conduit 204 can supply a sample gas to the water-permeable tubular membrane at the water-permeable tubular membrane inlet port 200. A sample gas outlet conduit 206 can allow the sample gas to flow from the water-permeable tubular membrane outlet port 202 to the assembly outlet 104.

[0050] In one instance, the water-permeable tubular membrane inlet port 200 may be connected to the water-permeable tubular membrane inlet conduit 204 at a 30 degree angle, as shown, for example, in Figure 2. The sample gas may be provided to the water-permeable tubular membrane by exiting the sample gas outlet 124, passing through the water-permeable tubular membrane inlet conduit 204, and entering the water-permeable tubular membrane at the water-permeable tubular membrane inlet port 200.

[0051] The water-permeable tubular membrane inlet port 200 may be connected to the water-permeable tubular membrane inlet conduit 204 at an angle between about 10 degrees and about 20 degrees, between about 20 degrees and about 30 degrees, between about 30 degrees and about 40 degrees, between about 40 degrees and about 50 degrees, between about 50 degrees and about 60 degrees, between about 60 degrees and about 70 degrees, between about 70 degrees and about 80 degrees, between about 80 degrees and about 90 degrees (e.g., as shown in FIG. 3 ), between about 90 degrees and about 100 degrees, between about 100 degrees and about 110 degrees, between about 110 degrees and about 120 degrees, between about 120 degrees and about 130 degrees, between about 130 degrees and about 140 degrees, between about 140 degrees and about 150 degrees, between about 150 degrees and about 160 degrees, or between about 160 degrees and about 170 degrees.

[0052] The water-permeable tubular membrane outlet port 202 may be connected to the sample gas outlet conduit 206 at a 30 degree angle, for example, as shown in Figure 2. The sample gas may exit the water-permeable tubular membrane at the water-permeable tubular membrane outlet port 202 and flow through the sample gas outlet conduit 206 to the assembly outlet 104.

[0053] The water-permeable tubular membrane outlet port 202 may be connected to the outlet conduit at an angle between 10 degrees and about 20 degrees, between about 20 degrees and about 30 degrees, between about 30 degrees and about 40 degrees, between about 40 degrees and about 50 degrees, between about 50 degrees and about 60 degrees, between about 60 degrees and about 70 degrees, between about 70 degrees and about 80 degrees, between about 80 degrees and about 90 degrees (e.g., as shown in FIG. 3 ), between about 90 degrees and about 100 degrees, between about 100 degrees and about 110 degrees, between about 110 degrees and about 120 degrees, between about 120 degrees and about 130 degrees, between about 1130 degrees and about 140 degrees, between about 140 degrees and about 150 degrees, between about 150 degrees and about 160 degrees, or between about 160 degrees and about 170 degrees.

[0054] 3 shows one example of a sample gas filter assembly 100. Sample gas filter assembly 100 can include a filter device 106 having a sample gas inlet 102 and a sample gas outlet 124. Sample gas filter assembly 100 can have a vent cap 114 configured to surround and house a water-permeable tubular membrane 300 and having the sample gas outlet 124 and an assembly outlet 104. Sample gas inlet 102 can be in fluid communication with assembly outlet 104, thereby establishing a fluid flow path through sample gas filter assembly 100 (e.g., from sample gas inlet 102 to assembly outlet 104).

[0055] The housing 126 of the filter device 106 may define an outer surface 302 and an inner surface 304 opposite the outer surface 302, as shown in Figure 3, for example. The thickness of the housing 126 may be defined by the distance between the outer surface 302 and the inner surface 304. The housing may have a substantially circular cross-section, which may define a diameter of the housing 126.

[0056] In one example, the housing 126 can include a first shell 306 and a second shell 308, which can define an outer surface 302 and a portion of an inner surface 304 of the housing 126, respectively. The first shell 306 can define a first surface 312 opposite the sample gas inlet 102. The second shell 308 can define a second surface 310 opposite the sample gas outlet 124. The first surface 312 of the first shell 306 can abut, in whole or in part, against the second surface 310 of the second shell 308 to form a housing 126 that is watertight. In one example, an ultrasonic weld 314 can join the first shell 306 and the second shell 308 at the first surface 312 and the second surface 310.

[0057] First chamber 110 can be located within housing 126. In other words, housing 126 of filter device 106 can, in whole or in part, define first chamber 110. In one case, first chamber 110 is defined in part by inner surface 304 of first shell 306. In one case, first chamber 110 can have a substantially circular cross-section, which can define a diameter of first chamber 110.

[0058] Second chamber 112 can be located within housing 126. In other words, housing 126 of filter device 106 can wholly or partially define second chamber 112. In one case, second chamber 112 is partially defined by inner surface 304 of second shell 308. In one case, second chamber 112 can have a substantially circular cross-section, which can define a diameter of second chamber 112.

[0059] For example, as shown in FIG. 3 , a first filter membrane 316 (e.g., a first stage of filtration) may be included in the first chamber 110. In one case, the first filter membrane 316 may be substantially circular in shape, which may define the diameter of the first filter membrane 316. The first filter membrane 316 may remove liquid (e.g., moisture, water vapor, water from humidified air, other liquids in a vapor state, nebulized liquids, nebulized medical solutions and suspensions, etc.) from the sample gas (e.g., the sample gas flowing through the first filter membrane 316), causing the liquid to coalesce and collect in the first reservoir 118 (e.g., a front reservoir), as shown in FIG. 1 . In some cases, the first filter membrane 316 may coalesce into liquids that are both oleophobic and hydrophobic. In one case, the first filter membrane 316 may be a glass fiber filter membrane.

[0060] In some cases, first filter membrane 316 can be held in place (e.g., secured) and / or sealed by the abutment of first surface 312 of first shell 306 and second surface 310 of second shell 308, for example, as shown in Figures 3 and 6. For example, ultrasonic weld 314 joining first surface 312 and second surface 310 can secure and / or seal first filter membrane 316.

[0061] For example, as shown in FIG. 1 , the first reservoir 118 can be included within the first chamber 110 (e.g., integrated into the housing 126). In some cases, the first reservoir 118 can be located between the sample gas inlet 102 and the first filter membrane 316. In other cases, the first reservoir can be located between the sample gas inlet 102 and a baffle plate (described in further detail below). The filter device 106 can remove liquid (e.g., humidity, water vapor, moisture from humidified air, other liquids in vapor state, nebulized liquids, nebulized medical solutions and suspensions, etc.) from the sample gas (e.g., via the first filter membrane 316) and collect the liquid in the first reservoir 118. The first reservoir can be axially oriented along the length of the filter so that the filter device 106 can operate (e.g., remove liquid from the sample gas and collect liquid) in any orientation during operation. The first reservoir 118 can define a volume and, in some cases, can be configured to contain water for approximately 12 hours of continuous use before needing to be replaced.

[0062] For example, as shown in FIG. 3, a second filter membrane 320 (e.g., a second stage of filtration) can be included in the second chamber 112. In one case, the second filter membrane can be substantially circular in shape, which can define the diameter of the second filter membrane 320. The second filter membrane 320 can remove liquid from the sample gas (e.g., the sample gas flowing through the second filter membrane 320) and cause the liquid to coalesce and collect in the second reservoir 120 (e.g., a rear reservoir), as shown in FIG. 1, for example. In some cases, the second filter membrane 320 can be a hydrophobic membrane.

[0063] The diameter of second filter membrane 320, in some examples, can be smaller than the diameter of first filter membrane 316. In other words, the diameter of first filter membrane 316 can be larger than the diameter of second filter membrane 320, for example, as shown in FIG.

[0064] The first filter membrane 316 and the second filter membrane 320 can, in some cases, be separated to prevent wicking between the first filter membrane 316 and the second filter membrane 320. For example, as shown in FIG. 3, a gap may exist between the first filter membrane 316 and the second filter membrane 320 to prevent wicking.

[0065] For example, as shown in FIG. 1 , the second reservoir 120 can be included within the second chamber 112 (e.g., integrated into the housing 126). In some cases, the second reservoir 120 can be located between the first filter membrane 316 and the sample gas outlet 124. In other cases, the second reservoir 120 can be located between the fabric membrane of the first chamber 110 and the press-fit baffle 318. The filter device 106 can remove liquid (e.g., humidity, water vapor, moisture from humidified air, other liquids in vapor state, nebulized liquids, nebulized medical solutions and suspensions, etc.) from the sample gas (e.g., via the second filter membrane 320) and collect the liquid in the second reservoir 120. The second reservoir 120 can be axially oriented along the length of the filter so that the filter device 106 can operate (e.g., remove liquid from the sample gas and collect liquid) in any orientation during operation. The second reservoir 120 can define a volume and, in some cases, can be configured to contain water for approximately 12 hours of continuous use before needing to be replaced.

[0066] The first reservoir 118 and the second reservoir 120 can be axially oriented to allow the filter device 106 to operate in any axial direction. In some cases, the first reservoir 118 and the second reservoir 120 can be large enough (e.g., have sufficient volume) to contain water for at least 12 hours of continuous use. The volume of the second reservoir 120 can, in some cases, be smaller than the volume of the first reservoir 118. In other words, the volume of the first reservoir 118 can be larger than the volume of the second reservoir 120, for example, as shown in FIG. 1 .

[0067] 3, a press-fit baffle 318 can be included in the second chamber 112. In some examples, the press-fit baffle 318 can mechanically support the second filter membrane 320 on a first side (e.g., a front side facing the sample gas flow) of the second filter membrane 320.

[0068] 3, a labyrinth support 322 can be included within the second chamber 112. The labyrinth support 322 can be located on the inner surface 304 of the housing 126 (e.g., the inner surface 304 of the second shell 308) near the permeable tubular membrane inlet conduit 204. In some examples, the labyrinth support 322 can mechanically support the second filter membrane 320 on a second side (e.g., the back side facing away from the flow of sample gas) of the second filter membrane 320. Furthermore, the labyrinth support 322 can facilitate effective circulation of the sample gas behind the second filter membrane 320.

[0069] Both the first filter membrane 316 and the second filter membrane 320 can be hydrophobic and / or oleophobic. The hydrophobic and / or oleophobic elements of the first filter membrane 316 and the second filter membrane 320 can filter liquids (e.g., humidity, water vapor, moisture from humidified air, other liquids in vapor state, nebulized liquids, nebulized medical solutions and suspensions, etc.) from the sample gas. One liquid that can be filtered is saline (e.g., NaCl). Filtering the sample gas before it enters the water-permeable tubular membrane 300 prevents or reduces the reaction between sodium in the saline and the water-permeable tubular membrane 300. Preventing or reducing the reaction between sodium and other cations and the water-permeable tubular membrane can eliminate the production of hydrochloric acid, thus preventing corrosion caused by hydrochloric acid in the sample line, gas sensor module, filter device, and therapeutic gas delivery device. Additionally, blockage (eg, clogging) of the sample line and the water-permeable tubular membrane can be prevented or reduced by filtering the sample gas before it flows through the water-permeable tubular membrane.

[0070] The filter device 106 can maintain a pH level of about 5.0 to about 6.0 for the condensate collected within the filter device 106. By maintaining a pH level of about 5.0 to about 6.0, the filter device 106 can ensure that liquids in the sample gas that react with the water-permeable tubular membrane 300 (e.g., saline (NaCl)) are filtered before entering the water-permeable tubular membrane 300. Preventing NaCl from entering the water-permeable tubular membrane 300 prevents a reaction between the water-permeable tubular membrane 300 and the sodium in the saline, thus eliminating the risk of downstream corrosion or blockage within the therapeutic gas delivery device and the sample gas filter assembly 100.

[0071] In another example, the concentrate can have a pH level of about 5.3 to about 6.0, hi another example, the concentrate can have a pH level of about 5.4 to about 5.6.

[0072] The filtered gas sample may be substantially free of saline before entering the permeable tubular membrane 300. In some examples, the filtered gas sample may be about 98% to about 98.5%, about 98.5% to about 99%, about 99% to about 99.5%, about 99.5% to about 99.95%, or about 99.95% to about 99.99% free of saline. In one example, the filtered gas sample may be substantially free of saline. In another example, the filtered gas sample may be 100% free of saline.

[0073] The sample gas filter assembly 100 can include a vent cap 114 that can be connected to the filter device 106. The vent cap 114 can be removably coupled to the second shell 308 of the filter device 106 at the exterior surface 302. The vent cap can be removably coupled to the exterior surface 302 of the second shell 308 via a snap-fit ​​connection, as shown, for example, in FIG. 3 . The vent cap can also be connected to the filter device 106 using other connection methods, such as threads, a barbed connection, or other connection mechanisms.

[0074] The water-permeable tubular membrane 300 can be fluidly connected at one end to the water-permeable tubular membrane inlet port 200 and at the other end to the water-permeable tubular membrane outlet port 202, for example, as shown in Figure 3. The water-permeable tubular membrane 300 can be housed within the vent cap 114. The water-permeable tubular membrane 300 can be attached to a water-permeable tubular membrane holder 108 to secure the water-permeable tubular membrane 300 within the vent cap. The water-permeable tubular membrane holder 108 can be in the shape of a hook, for example, as shown in Figure 1.

[0075] In one example, the sample gas outlet 124 can discharge the sample gas from the filter apparatus 106 to a water-permeable tubular membrane inlet conduit 204. The water-permeable tubular membrane inlet conduit 204 can provide the filtered sample gas to a water-permeable tubular membrane 300 at the water-permeable tubular membrane inlet port 200. The water-permeable tubular membrane 300 can discharge the sample gas at the water-permeable tubular membrane outlet port 202. The sample gas flows through the sample gas outlet conduit 206 and can be discharged at the assembly outlet 104 to a gas sensor module of the therapeutic gas delivery device.

[0076] The water-permeable tubular membrane 300 can be formed from a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer. In one example, the water-permeable tubular membrane 300 can be a tubing made of a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer (e.g., Nafion®).

[0077] The water-permeable tubular membrane 300 can be configured to humidify the sample gas. The water-permeable tubular membrane 300 can be exposed to ambient air flow through the vent opening 116 in the vent cap 114. The water-permeable tubular membrane 300 can humidify the sample gas by conditioning the sample gas to match the humidity of the ambient air. The water-permeable tubular membrane 300 can remove water vapor from the sample gas to reduce the humidity of the sample gas to match the humidity of the ambient air. In another example, the water-permeable tubular membrane 300 can increase the humidity of the sample gas if the humidity of the sample gas is lower than the humidity of the ambient air. The humidified sample gas can then flow through the assembly outlet 104 to a gas sensor module, where the sample gas can be analyzed. Humidifying the sample gas before it enters the sensor of the gas sensor module provides more accurate readings and promotes the life of the sensors and other components in the therapy delivery device and sample gas filter assembly 100.

[0078] The humidity-adjusted gas may be substantially free of saline. In some cases, the humidity-adjusted gas may be 98%, 98.5%, 99%, 99.5%, 99.95%, or 99.99% saline-free.

[0079] 4 illustrates one example of a sample gas filter assembly 100. In some examples, a baffle plate 400 can be included in the first chamber 110, for example, as shown in FIG. 4. In some examples, the baffle plate 400 can mechanically support the first filter membrane 316 on a second side (e.g., a back side facing away from the sample gas flow) of the first filter membrane 316.

[0080] 5 illustrates one example of a sample gas filter assembly 100. The sample gas filter assembly can provide a fluid flow path for the sample gas from a sample gas inlet 102 to an assembly outlet 104. The sample gas filter assembly 100 can be configured for one-handed installation.

[0081] 6 illustrates one example of a sample gas filter assembly 100. A fiber membrane 600 can, in some cases, be included within the first chamber 110. In some examples, the fiber membrane 600 can mechanically support the first filter membrane 316 on a second side (e.g., a back side facing away from the sample gas flow) of the first filter membrane 316. In one example, the fiber membrane 600 can be a coarse Vyon fiber membrane.

[0082] The sample line (the line attached to sample gas inlet 102) and / or the sample gas filter assembly including sample gas filter assembly 100 can be removed and replaced as needed. In other words, the existing sample line and / or sample gas filter assembly 100 can be removed from the therapeutic gas delivery device, and a new sample line and / or sample gas filter assembly 100 can be connected in its place, as described above.

[0083] Also provided herein is a method for humidifying and filtering a sample gas in a therapeutic gas delivery device. The flowchart seen in FIG. 7 is presented according to an exemplary embodiment. This method is provided as an example, as there are various ways to perform this method. The method 700 described below can be performed, for example, using the configurations shown in the figures, and various elements of these figures will be referenced in describing the exemplary method 700. Each block represents one or more processes, methods, or subroutines performed in the exemplary method 700. Furthermore, the depicted order of the blocks in FIG. 7 is merely exemplary, and the order of the blocks can be changed in accordance with the present disclosure. Additional blocks may be added or fewer blocks may be utilized without departing from the present disclosure.

[0084] Exemplary method 700 is a method for humidifying and filtering a sample gas in a therapeutic gas delivery device. The exemplary method may begin at block 702. In block 702, the method includes passing a sample gas through a filter apparatus (e.g., a sample gas filter) of an assembly. The sample gas may be supplied to the sample gas filter at a sample gas inlet. The sample gas may flow through the sample gas inlet to a first filter membrane. The first filter membrane may be hydrophobic and / or oleophobic. In the first filter membrane, liquids (such as moisture, water vapor, moisture from humidified air, other liquids in vapor state, nebulized liquids, nebulized medical solutions and suspensions) may be filtered from the sample gas. The first filter membrane may also filter saline from the sample gas. The sample gas may then pass through a second filter membrane. In the second filter membrane, liquids (such as moisture, water vapor, moisture from humidified air, other liquids in vapor state, nebulized liquids, nebulized medical solutions and suspensions) may be further filtered from the sample gas.

[0085] At block 704, the method includes collecting condensate from the sample gas in the filter device. Liquid blocked by the first filter membrane can be collected in a first reservoir located in a first chamber of the sample gas filter. The first reservoir can also collect any saline solution blocked by the first filter membrane. Liquid can be collected in a second reservoir located in a second chamber of the sample gas filter. A pH level of 5.0 to 6.0 can be maintained in the collected condensate. Maintaining a pH level of 5.0 to 6.0 in the condensate ensures that any salt or sodium is filtered before entering the permeable tubular membrane, preventing any reaction within the permeable tubular membrane that could produce hydrochloric acid.

[0086] At block 706, the method includes passing the filtered sample gas through a water-permeable tubular membrane of the assembly. The sample gas exiting the water-permeable tubular membrane is humidity-conditioned gas. The water-permeable tubular membrane can be contained within a vent cap connected to the sample gas filter. The vent cap can have at least one vent opening that allows ambient air to contact the water-permeable tubular membrane. When ambient air contacts the outer surface of the water-permeable tubular membrane, the water-permeable tubular membrane can release water vapor from the sample gas to humidify the sample gas. The sample gas is humidified by the water-permeable tubular membrane to have the same humidity as the ambient air.

[0087] The sample gas can be humidity-adjusted with a confidence level of at least 98% to about 99%, about 99% to about 99.5%, about 99.5% to about 99.9%, about 99.9% to about 99.95%, or higher. The humidity-adjusted gas may be substantially free of saline. The humidity-adjusted gas may be about 98% to about 99%, about 99% to about 99.5%, or about 99.5% to about 99.95% free of saline. In some examples, the humidity-adjusted gas may be substantially free of saline. In one example, the humidity-adjusted gas may be 100% free of saline.

[0088] By filtering a liquid containing saline before the liquid reaches the water-permeable tubular membrane, the production of hydrochloric acid is prevented or reduced. Preventing or reducing the production of hydrochloric acid can significantly reduce corrosion of the filter apparatus and corrosion of the therapeutic gas delivery device. Furthermore, by preventing sodium from reacting with the water-permeable tubular membrane, clogging of the sample line, sample pump, and / or water-permeable tubular membrane can be significantly reduced. Clogging of the sample line connected to the assembly, clogging of the pump connected to the sample line, corrosion of the sample gas filter, and / or corrosion within the therapeutic gas delivery device can be reduced or prevented with a 98% confidence level.

[0089] The assembly can maintain the condensate at a pH of about 5.0 to about 6.0. In another example, the assembly can maintain the condensate at a pH of about 5.3 to about 6.0. In a further example, the assembly can maintain the condensate at a pH of about 5.4 to about 5.6.

[0090] Also provided herein is a method for maintaining condensate pH from an assembly for humidifying and filtering sample gas in a therapeutic gas delivery device. The flowchart seen in FIG. 8 is presented according to an exemplary embodiment. This method is provided as an example, as there are various ways to perform this method. The method 800 described below can be performed, for example, using the configurations shown in the figures, and various elements of these figures will be referenced in describing the exemplary method 800. Each block represents one or more processes, methods, or subroutines performed in the exemplary method 800. Furthermore, the depicted order of the blocks in FIG. 8 is merely exemplary, and the order of the blocks can be changed in accordance with the present disclosure. Additional blocks may be added or fewer blocks may be utilized without departing from the present disclosure.

[0091] Exemplary method 800 is a method for maintaining condensate pH from an assembly for humidifying and filtering a sample gas in a therapeutic gas delivery device. The exemplary method can begin at block 802. In block 802, the method includes passing a sample gas through a filter apparatus (e.g., a sample gas filter) of the assembly. The sample gas can be supplied to the filter apparatus at a sample gas inlet. The sample gas can flow through the sample gas inlet to a first filter membrane. The first filter membrane can be hydrophobic and / or oleophobic. At the first filter membrane, liquids (e.g., moisture, water vapor, moisture from humidified air, other liquids in vapor state, nebulized liquids, nebulized medical solutions and suspensions, etc.) can be filtered from the sample gas. The first filter membrane can also filter saline from the sample gas. The sample gas can then pass through a second filter membrane. At the second filter membrane, liquids (e.g., moisture, water vapor, moisture from humidified air, other liquids in vapor state, nebulized liquids, nebulized medical solutions and suspensions, etc.) can be filtered from the sample gas.

[0092] At block 804, the method includes collecting condensate from the sample gas in the filter device. Liquid filtered by the first filter membrane may be collected in a first reservoir located in a first chamber of the filter device. The first reservoir may also collect saline solution filtered by the first filter membrane. Liquid filtered by the second filter membrane may be collected in a second reservoir located in a second chamber of the sample gas filter. A pH level of 5.0 to 6.0 may be maintained in the collected condensate. Maintaining a pH level of 5.0 to 6.0 in the condensate ensures that any salt or sodium from the saline solution is filtered before entering the permeable tubular membrane, preventing any reaction within the permeable tubular membrane that could produce hydrochloric acid.

[0093] At block 806, the method includes passing the filtered sample gas through a water-permeable tubular membrane of the assembly. The sample gas exiting the water-permeable tubular membrane is humidity-conditioned gas. The water-permeable tubular membrane can be contained within a vent cap connected to the sample gas filter. The vent cap can have at least one vent opening that allows ambient air to contact the water-permeable tubular membrane. When ambient air contacts the outer surface of the water-permeable tubular membrane, the water-permeable tubular membrane can release water vapor from the sample gas to humidify the sample gas. The sample gas is humidified by the water-permeable tubular membrane to have the same humidity as the ambient air.

[0094] The sample gas may be humidified to a confidence level of at least 98%, 99%, 99.5%, 99.9%, or 99.95%. The humidified gas may be substantially free of saline. The humidified gas may be 98%, 99%, 99.5%, or 99.95% free of saline.

[0095] By filtering a liquid containing saline before the liquid reaches the water-permeable tubular membrane, the production of hydrochloric acid is prevented or reduced. Preventing or reducing the production of hydrochloric acid can significantly reduce corrosion of the filter apparatus and corrosion of the therapeutic gas delivery device. Furthermore, by preventing sodium from reacting with the water-permeable tubular membrane, clogging of the sample line, sample pump, and / or water-permeable tubular membrane can be significantly reduced. Clogging of the sample line connected to the assembly, clogging of the pump connected to the sample line, corrosion of the sample gas filter, and / or corrosion within the therapeutic gas delivery device can be reduced or prevented with a 98% confidence level.

[0096] The method can include maintaining the condensate at a pH of about 5.0 to about 6.0. In another example, the assembly can maintain the condensate at a pH of about 5.3 to about 6.0. In a further example, the assembly can maintain the condensate at a pH of about 5.4 to about 5.6.

[0097] Further provided herein is a method for preventing degradation or corrosion in a therapeutic gas delivery device. The flowchart seen in FIG. 9 is presented according to an exemplary embodiment. This method is provided as an example, as there are various ways to perform this method. The method 900 described below can be performed, for example, using the configurations shown in the figures, and various elements of these figures will be referenced in describing the exemplary method 900. Each block represents one or more processes, methods, or subroutines performed in the exemplary method 900. Furthermore, the depicted order of the blocks in FIG. 9 is merely exemplary, and the order of the blocks can be changed in accordance with the present disclosure. Additional blocks may be added or fewer blocks may be utilized without departing from the present disclosure.

[0098] Exemplary method 900 is a method for preventing deterioration or corrosion of a therapeutic gas delivery device. The exemplary method may begin at block 902. In block 902, the method includes passing a sample gas through a filter apparatus (e.g., a sample gas filter) of an assembly. The sample gas may be supplied to the filter apparatus at a sample gas inlet. The sample gas may flow through the sample gas inlet to a first filter membrane. The first filter membrane may be hydrophobic and / or oleophobic. At the first filter membrane, liquids (e.g., moisture, water vapor, moisture from humidified air, other liquids in vapor state, nebulized liquids, nebulized medical solutions and suspensions, etc.) may be filtered from the sample gas. The first filter membrane may also filter saline from the sample gas. The sample gas may then pass through a second filter membrane. At the second filter membrane, liquids (e.g., moisture, water vapor, moisture from humidified air, other liquids in vapor state, nebulized liquids, nebulized medical solutions and suspensions, etc.) may be filtered from the sample gas.

[0099] At block 904, the method includes collecting condensate from the sample gas in the filter device. Liquid filtered by the first filter membrane may be collected in a first reservoir located in a first chamber of the filter device. The first reservoir may also collect saline solution blocked by the first filter membrane. Liquid filtered by the second filter membrane may be collected in a second reservoir located in a second chamber of the sample gas filter. A pH level of 5.0 to 6.0 may be maintained in the collected condensate. Maintaining a pH level of 5.0 to 6.0 in the condensate ensures that any salt or sodium from the saline solution is filtered before entering the permeable tubular membrane, preventing any reaction within the permeable tubular membrane that could produce hydrochloric acid.

[0100] At block 906, the method includes passing the filtered sample gas through a water-permeable tubular membrane of the assembly. The sample gas exiting the water-permeable tubular membrane is humidity-conditioned gas. The water-permeable tubular membrane can be contained within a vent cap connected to the sample gas filter. The vent cap can have at least one vent opening that allows ambient air to contact the water-permeable tubular membrane. When ambient air contacts the outer surface of the water-permeable tubular membrane, the water-permeable tubular membrane can release water vapor from the sample gas to humidify the sample gas. The sample gas is humidified by the water-permeable tubular membrane to have the same humidity as the ambient air.

[0101] The humidity-adjusted gas may be substantially free of saline. The humidity-adjusted gas may be 98%, 99%, 99.5%, or 99.95% free of saline.

[0102] By filtering the saline-containing liquid before the liquid reaches the water-permeable tubular membrane, the production of hydrochloric acid is prevented or reduced. Preventing or reducing the production of hydrochloric acid can significantly reduce corrosion of the sample gas filter and corrosion of the therapeutic gas delivery device. Furthermore, by preventing sodium from reacting with the water-permeable tubular membrane, clogging of the sample line, sample pump, and / or water-permeable tubular membrane can be significantly reduced. Clogging of the sample line connected to the assembly, clogging of the pump connected to the sample line, corrosion of the sample gas filter, and / or corrosion within the therapeutic gas delivery device can be reduced or prevented with a 98% confidence level.

[0103] The method can include maintaining the condensate at a pH of about 5.0 to about 6.0. In another example, the assembly can maintain the condensate at a pH of about 5.3 to about 6.0. In a further example, the assembly can maintain the condensate at a pH of about 5.4 to about 5.6.

[0104] At block 908, the method includes preventing the sample gas from contacting the sensor without first being humidified to a 98% confidence level. The sample gas may be humidified by a water-permeable tubular membrane. The sample gas may be humidified to a 98%, 98.5%, 99%, 99.5%, 99.95%, or 99.99% confidence level.

[0105] Further provided herein is a method for preventing degradation or corrosion in a therapeutic gas delivery device. The flowchart seen in FIG. 10 is presented according to an exemplary embodiment. This method is provided as an example, as there are various ways to perform this method. The method 1000 described below can be performed, for example, using the configurations shown in the figures, and various elements of these figures will be referenced in describing the exemplary method 1000. Each block represents one or more processes, methods, or subroutines performed in the exemplary method 1000. Furthermore, the depicted order of the blocks in FIG. 10 is merely exemplary, and the order of the blocks can be changed in accordance with the present disclosure. Additional blocks may be added or fewer blocks may be utilized without departing from the present disclosure.

[0106] Exemplary method 1000 is a method for preventing deterioration or corrosion of a therapeutic gas delivery device. The exemplary method may begin at block 1002. In block 1002, the method includes passing a sample gas through a filter apparatus (e.g., a sample gas filter) of an assembly. The sample gas may be supplied to the filter apparatus at a sample gas inlet. The sample gas may flow through the sample gas inlet to a first filter membrane. The first filter membrane may be hydrophobic and / or oleophobic. At the first filter membrane, liquids (e.g., moisture, water vapor, moisture from humidified air, other liquids in vapor state, nebulized liquids, nebulized medical solutions and suspensions, etc.) may be filtered from the sample gas. The first filter membrane may also filter saline from the sample gas. The sample gas may then pass through a second filter membrane. At the second filter membrane, liquids (e.g., moisture, water vapor, moisture from humidified air, other liquids in vapor state, nebulized liquids, nebulized medical solutions and suspensions, etc.) may be filtered from the sample gas.

[0107] At block 1004, the method includes collecting condensate from the sample gas in the filter device. Liquid filtered by the first filter membrane may be collected in a first reservoir located in a first chamber of the filter device. The first reservoir may also collect saline intercepted by the first filter membrane. Liquid filtered by the second filter membrane may be collected in a second reservoir located in a second chamber of the sample gas filter.

[0108] At block 1006, the method includes passing the filtered sample gas through a water-permeable tubular membrane of the assembly. The sample gas exiting the water-permeable tubular membrane is humidity-conditioned gas. The water-permeable tubular membrane can be contained within a vent cap connected to the sample gas filter. The vent cap can have at least one vent opening that allows ambient air to contact the water-permeable tubular membrane. When ambient air contacts the outer surface of the water-permeable tubular membrane, the water-permeable tubular membrane can release water vapor from the sample gas to humidify the sample gas. The sample gas is humidified by the water-permeable tubular membrane to have the same humidity as the ambient air.

[0109] The sample gas may be humidified to a confidence level of at least 98%, 99%, 99.5%, 99.9%, or 99.95%. The humidified gas may be substantially free of saline. The humidified gas may be 98%, 99%, 99.5%, or 99.95% free of saline.

[0110] At block 1008, the method includes maintaining the condensate at a pH of about 5.0 to about 6.0 with a 98% confidence level. Maintaining the condensate at a pH level of 5.0 to 6.0 ensures that any salt or sodium from the saline solution is filtered before entering the water-permeable tubular membrane, preventing any reaction within the water-permeable tubular membrane that could produce hydrochloric acid.

[0111] In another example, the assembly can maintain the condensate at a pH of about 5.3 to about 6.0. In a further example, the assembly can maintain the condensate at a pH of about 5.4 to about 5.6.

[0112] By filtering the saline-containing liquid before the liquid reaches the water-permeable tubular membrane, the production of hydrochloric acid is prevented or reduced. Preventing or reducing the production of hydrochloric acid can significantly reduce corrosion of the sample gas filter and corrosion of the therapeutic gas delivery device. Furthermore, by preventing sodium from reacting with the water-permeable tubular membrane, clogging of the sample line, sample pump, and / or water-permeable tubular membrane can be significantly reduced. Clogging of the sample line connected to the assembly, clogging of the pump connected to the sample line, corrosion of the sample gas filter, and / or corrosion within the therapeutic gas delivery device can be reduced or prevented with a 98% confidence level.

[0113] The foregoing merely illustrates the principles of the present invention. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in light of the teachings herein. It should thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements, and methods which, although not explicitly shown or described herein, embody the principles of the present invention and therefore are within the spirit and scope of the present invention. From the above description and drawings, those skilled in the art will appreciate that the specific embodiments shown and described are for illustrative purposes only and are not intended to limit the scope of the invention. Reference to details of specific embodiments is not intended to limit the scope of the invention.

[0114] Reference to an "embodiment," "aspect," "case," or "example" means that a particular feature, structure, or characteristic described in connection with one embodiment is included in at least one embodiment of the present disclosure. The appearances of the phrases "embodiment," "aspect," "case," or "example" in various places throughout this specification do not necessarily all refer to the same embodiment, nor are they separate or alternative embodiments mutually exclusive of other embodiments. Furthermore, various features are described that may be exhibited by some embodiments and not by other embodiments.

[0115] The terms used herein generally have their ordinary meaning in the art, within the context of this disclosure and in the specific context in which each term is used. Alternative language and synonyms may be used for any one or more of the terms discussed herein, and no particular importance should be placed on whether a term is recited or discussed herein. In some cases, synonyms for a particular term are provided. The recitation of one or more synonyms does not preclude the use of other synonyms. The use of examples anywhere in this specification, including examples of any term discussed herein, is merely illustrative and does not further limit the scope and meaning of the disclosure or any exemplary term. Similarly, the present disclosure is not limited to the various embodiments provided herein. [Example]

[0116] Table 1 shows the results of operating therapeutic gas delivery devices with different sample gas filter assembly configurations. Devices 6 and 10 were sample gas filter assemblies using the configuration described in the previous disclosure. Devices 6 and 10 consisted of a sample gas line supplying sample gas to a sample gas inlet and a filter device containing two filter membranes. Condensate was collected in the sample gas filter, and the pH of the condensate was measured. The sample gas was then supplied to the water-permeable tubular membrane via the sample gas outlet and the water-permeable tubular membrane inlet conduit. The sample gas flowed through the water-permeable tubular membrane and exited at the assembly outlet. The sample gas then entered the gas sensor module of the therapeutic gas delivery device. Device 9 consisted of a different sample gas filter assembly configuration. Gas first flowed through the water-permeable tubular membrane, then through the filter device, and then through the sample gas outlet into the therapeutic gas delivery device. Condensate was collected in the sample gas filter, and the pH of the condensate was measured. As shown in Table 1, filtering the sample gas before humidity conditioning with a water-permeable tubular membrane reduces or prevents the formation of corrosive acids (pH 1-2). [Table 1]

[0117] Illustrative Embodiments Below is a list of exemplary embodiments, which may include combinations thereof.

[0118] Embodiment 1: A filter assembly for a therapeutic gas delivery device, the assembly comprising: a filter apparatus comprising an inlet, an outlet, at least one reservoir, and at least one filter membrane between the inlet and the outlet, the filter apparatus operable to remove water vapor from a sample gas and collect condensate in the at least one reservoir; a water-permeable tubular membrane fluidly connected to the outlet of the filter apparatus; and a vent cap connected to the filter apparatus and surrounding the outlet, the vent cap comprising a vent opening.

[0119] Embodiment 2: The assembly of embodiment 1, wherein the water-permeable tubular membrane is configured to humidify the sample gas.

[0120] Embodiment 3: The assembly of embodiment 1, wherein the vent cap comprises a plurality of vent openings.

[0121] Embodiment 4: The assembly of embodiment 1, wherein the vent cap is configured to receive and secure the water-permeable tubular membrane.

[0122] Embodiment 5: The assembly of embodiment 1, wherein the water-permeable tubular membrane is formed from a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer.

[0123] Embodiment 6: The assembly of embodiment 1, wherein the water-permeable tubular membrane is a tubing comprising a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer.

[0124] Embodiment 7: The assembly of embodiment 1, wherein the filter apparatus comprises: a housing having a sample gas inlet and a sample gas outlet, the sample gas inlet operable to receive sample gas from a sample line connected to the inlet line of the therapeutic gas delivery device; a first filter membrane; a first reservoir disposed between the sample gas inlet and the first filter membrane; and a second chamber disposed within the housing, the second chamber comprising a second filter membrane and a second reservoir disposed between the first filter membrane and the sample gas outlet.

[0125] Embodiment 8: The assembly of embodiment 7, wherein the first reservoir and the second reservoir are axially oriented such that the filter device is operable to be used in any axial orientation.

[0126] Embodiment 9: The assembly of embodiment 7, wherein the housing, each of the chambers, and each of the filter membranes have a substantially circular cross-section.

[0127] Embodiment 10: An assembly according to embodiment 1, wherein at least one reservoir is large enough to contain water for 12 hours of continuous use.

[0128] Embodiment 11: The assembly of embodiment 1, wherein at least one reservoir has a volume of at least 10 cubic centimeters.

[0129] Embodiment 12: The assembly of embodiment 1, wherein the assembly is configured to be placed into a therapeutic gas delivery device with one hand.

[0130] Embodiment 13: A method for humidifying and filtering a sample gas in a therapeutic gas delivery device, the method comprising: passing the sample gas through a filter apparatus of an assembly; collecting condensate from the sample gas in the filter apparatus; and passing the filtered sample gas through a water-permeable tubular membrane of the assembly, wherein the sample gas exiting the water-permeable tubular membrane is a humidity-adjusted sample gas.

[0131] Embodiment 14: The method of embodiment 13, wherein the sample gas exiting the water-permeable tubular membrane is a humidity-adjusted sample gas with at least a 98% confidence level.

[0132] Embodiment 15: The method of embodiment 13, wherein the sample gas exiting the water-permeable tubular membrane is a humidity-adjusted sample gas with at least a 99% confidence level.

[0133] Embodiment 16: The method of embodiment 13, wherein the sample gas exiting the water-permeable tubular membrane is a humidity-adjusted sample gas with a confidence level of at least 99.5%.

[0134] Embodiment 17: The method of embodiment 13, wherein the sample gas exiting the water-permeable tubular membrane is a humidity-adjusted sample gas with at least a 99.9% confidence level.

[0135] Embodiment 18: The method of embodiment 13, wherein the sample gas exiting the water-permeable tubular membrane is a humidity-adjusted sample gas with at least a 99.95% confidence level.

[0136] Embodiment 19: The method of embodiment 13, further comprising exposing the exterior surface of the water-permeable tubular membrane to an ambient air flow.

[0137] Embodiment 20: The method of embodiment 13, wherein the humidity-adjusted sample gas is substantially free of saline.

[0138] Embodiment 21: The method of embodiment 13, further comprising reducing or preventing the production of HCl in the therapeutic gas delivery device.

[0139] Embodiment 22: The method of embodiment 13, further comprising reducing or preventing, with at least a 98% confidence level, clogging of a sample line connected to the assembly, clogging of a pump connected to the sample line, corrosion of a filter device, and / or corrosion within the therapeutic gas delivery device.

[0140] Embodiment 23: The method of embodiment 13, wherein the assembly maintains the condensate at a pH of about 5.0 to about 6.0.

[0141] Embodiment 24: The method of embodiment 13, wherein the assembly maintains the condensate at a pH of about 5.3 to about 6.0.

[0142] Embodiment 25: The method of embodiment 13, wherein the assembly maintains the condensate at a pH of about 5.4 to about 5.6.

[0143] Embodiment 26: A method of maintaining a condensate pH from an assembly for humidifying and filtering a sample gas in a therapeutic gas delivery device, the method comprising: passing the sample gas through a filter apparatus of the assembly; collecting condensate from the sample gas in the filter apparatus; and passing the filtered sample gas through a water-permeable tubular membrane of the assembly, wherein the sample gas exiting the water-permeable tubular membrane is a humidity-controlled sample gas, wherein the assembly maintains the condensate at a pH of 5.0 to 6.0.

[0144] Embodiment 27: The method of embodiment 26, wherein the humidity-adjusted sample gas is substantially free of saline.

[0145] Embodiment 28: The method of embodiment 26, further comprising exposing the exterior surface of the water-permeable tubular membrane to an ambient air flow.

[0146] Embodiment 29: The method of embodiment 26, wherein the assembly reduces or prevents the production of HCl in the therapeutic gas delivery device.

[0147] Embodiment 30: The method of embodiment 26, wherein the assembly reduces or prevents clogging of a sample line connected to the assembly, clogging of a pump connected to the sample line, corrosion of a filter device, or corrosion within a therapeutic gas delivery device.

[0148] Embodiment 31: A method for preventing degradation or corrosion in a therapeutic gas delivery device, the method comprising: passing a sample gas through a filter apparatus of an assembly; collecting condensate from the sample gas in the filter apparatus; passing the filtered sample gas through a water-permeable tubular membrane of the assembly, wherein the sample gas exiting the water-permeable tubular membrane is humidity-conditioned sample gas; and preventing, with at least a 98% confidence level, the sample gas from contacting a sensor without first being humidity-conditioned.

[0149] Embodiment 32: A method for preventing degradation or corrosion in a therapeutic gas delivery device, the method comprising: passing a sample gas through a filter apparatus of an assembly; collecting condensate from the sample gas in the filter apparatus; passing the filtered sample gas through a water-permeable tubular membrane of the assembly, wherein the sample gas exiting the water-permeable tubular membrane is humidity-controlled sample gas; and maintaining the condensate at a pH of about 5.0 to about 6 with at least a 98% confidence level.

[0150] While multiple embodiments have been described, those skilled in the art will recognize that various modifications, alternative constructions, and equivalents may be used without departing from the spirit of the present invention. Moreover, in order to avoid unnecessarily obscuring the present invention, some well-known processes and elements have not been described. Therefore, the above description should not be construed as limiting the scope of the present invention.

[0151] Those skilled in the art will understand that the embodiments disclosed herein are taught by way of example and not by way of limitation. Accordingly, the matter contained in the above description or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense. The following claims are intended to encompass all general and specific features described herein, as well as all statements of the scope of the present systems and methods that may be said to fall therebetween as a matter of language.

Claims

1. 1. A filter assembly for a therapeutic gas delivery device, said assembly comprising: a filter device comprising an inlet, an outlet, at least one reservoir, and at least one filter membrane between the inlet and the outlet, the filter device operable to remove water vapor from the sample gas and collect condensate in the at least one reservoir; a water-permeable tubular membrane fluidly connected to the outlet of the filter device; a vent cap connected to the filter device and surrounding the outlet, the vent cap including a vent opening.

2. The assembly of claim 1 , wherein the water-permeable tubular membrane is configured to humidify the sample gas.

3. The assembly of claim 1 , wherein the vent cap comprises a plurality of vent openings.

4. The assembly of claim 1 , wherein the vent cap is configured to receive and secure the water-permeable tubular membrane.

5. 10. The assembly of claim 1, wherein the water-permeable tubular membrane is formed from a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer.

6. 10. The assembly of claim 1, wherein the water-permeable tubular membrane is a tubing comprising a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer.

7. The filter device comprises: a housing having a sample gas inlet and a sample gas outlet, the sample gas inlet operable to receive sample gas from a sample line connected to an inspiratory line of the therapeutic gas delivery device; a first chamber disposed within the housing, the first chamber comprising: a first filter membrane; a first chamber comprising a first reservoir disposed between the sample gas inlet and the first filter membrane; a second chamber disposed within the housing, the second chamber comprising: a second filter membrane; 10. The assembly of claim 1, further comprising: a second chamber comprising: a second reservoir disposed between the first filter membrane and the sample gas outlet.

8. 8. The assembly of claim 7, wherein the first reservoir and the second reservoir are axially oriented such that the filter device is operable for use in any axial orientation.

9. The assembly of claim 7 , wherein the housing, each of the chambers, and each of the filter membranes have a substantially circular cross section.

10. 10. The assembly of claim 1, wherein the at least one reservoir is large enough to contain water for 12 hours of continuous use.

11. The assembly of claim 1 , wherein the at least one reservoir has a volume of at least 10 cubic centimeters.

12. The assembly of claim 1 , wherein the assembly is configured to be placed into the therapeutic gas delivery device with one hand.

13. 1. A method for humidifying and filtering a sample gas in a therapeutic gas delivery device, the method comprising: passing the sample gas through a filter device of an assembly; collecting condensate from the sample gas in the filter device; passing the filtered sample gas through a water-permeable tubular membrane of the assembly, wherein the sample gas exiting the water-permeable tubular membrane is a humidity-controlled sample gas.

14. 14. The method of claim 13, wherein the sample gas exiting the water-permeable tubular membrane is a humidity-adjusted sample gas with at least a 98% confidence level.

15. 14. The method of claim 13, wherein the sample gas exiting the water-permeable tubular membrane is a humidity-controlled sample gas with at least a 99% confidence level.

16. 14. The method of claim 13, wherein the sample gas exiting the water-permeable tubular membrane is a humidity-adjusted sample gas with at least a 99.5% confidence level.

17. 14. The method of claim 13, wherein the sample gas exiting the water-permeable tubular membrane is a humidity-controlled sample gas with at least a 99.9% confidence level.

18. 14. The method of claim 13, wherein the sample gas exiting the water-permeable tubular membrane is a humidity-adjusted sample gas with at least a 99.95% confidence level.

19. The method of claim 13 further comprising exposing an exterior surface of the water-permeable tubular membrane to an ambient air flow.

20. 14. The method of claim 13, wherein the humidity-adjusted sample gas is substantially free of saline.

21. 14. The method of claim 13, further comprising reducing or preventing the production of HCl within the therapeutic gas delivery device.

22. 14. The method of claim 13, further comprising reducing or preventing, with at least a 98% confidence level, clogging of a sample line connected to the assembly, clogging of a pump connected to the sample line, corrosion of the filter apparatus, and / or corrosion within the therapeutic gas delivery device.

23. The method of claim 13, wherein the assembly maintains the condensate at a pH of about 5.0 to about 6.

0.

24. The method of claim 13, wherein the assembly maintains the condensate at a pH of about 5.3 to about 6.

0.

25. The method of claim 13, wherein the assembly maintains the condensate at a pH of about 5.4 to about 5.

6.

26. 1. A method for maintaining condensate pH from an assembly for humidifying and filtering a sample gas in a therapeutic gas delivery device, the method comprising: passing the sample gas through a filter device of the assembly; collecting condensate from the sample gas in the filter device; passing the filtered sample gas through a water-permeable tubular membrane of the assembly, wherein the sample gas exiting the water-permeable tubular membrane is a humidity-adjusted sample gas; The method wherein the assembly maintains the condensate at a pH of 5.0 to 6.

0.

27. 27. The method of claim 26, wherein the humidity-adjusted sample gas is substantially free of saline.

28. 27. The method of claim 26, further comprising exposing an exterior surface of the water-permeable tubular membrane to an ambient air flow.

29. 27. The method of claim 26, wherein the assembly reduces or prevents the generation of HCl within the therapeutic gas delivery device.

30. 27. The method of claim 26, wherein the assembly reduces or prevents clogging of a sample line connected to the assembly, clogging of a pump connected to the sample line, corrosion of the filter apparatus, or corrosion within the therapeutic gas delivery device.

31. 1. A method for preventing degradation or corrosion in a therapeutic gas delivery device, the method comprising: passing the sample gas through a filter device of the assembly; collecting condensate from the sample gas in the filter device; passing the filtered sample gas through a water-permeable tubular membrane of the assembly, wherein the sample gas exiting the water-permeable tubular membrane is a humidity-controlled sample gas; and preventing, with at least a 98% confidence level, the sample gas from contacting the sensor without first being humidified.

32. 1. A method for preventing degradation or corrosion in a therapeutic gas delivery device, the method comprising: passing the sample gas through a filter device of the assembly; collecting condensate from the sample gas in the filter device; passing the filtered sample gas through a water-permeable tubular membrane of the assembly, wherein the sample gas exiting the water-permeable tubular membrane is a humidity-controlled sample gas; and maintaining the condensate at a pH of about 5.0 to about 6 with at least a 98% confidence level.

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