Apparatus and method for gas sampling container

Abstract

Methods and systems for collecting, transporting and extracting high-quality fluid samples for laboratory analysis are disclosed. The disclosed systems and methods are particularly important for collecting fluid samples in a manner that best resembles the captured fluid and safely maintaining the samples during transportation and extraction in the laboratory.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 62 / 682,885, filed on June 9, 2018, and Patent Cooperation Treaty Patent Application Serial No. PCT / US2019 / 036202, filed on June 9, 2019. The disclosures of the above applications are incorporated herein by reference in their entirety. Technical Field

[0003] Embodiments of the present disclosure relate generally to tools and techniques for collecting and testing pressurized and non-pressurized gas samples, and more particularly, to novel gas sampling devices and methods. Background Art

[0004] In many industries, including the oil and gas industry, it is known to sample gases and fluids on a regular basis. These sample gases and sample fluids are captured using specialized containers and transported from the field to a laboratory for analysis. As used herein, gases are often specifically referenced, but gases also include other phases of matter included in the fluid subset, such as liquids and other fluids.

[0005] A sample of the reservoir fluid is typically obtained by using a specialized tool that enters the borehole. A vent tube in the tool probe may be sealed to the formation at the location of interest and have an internal conduit leading to a pump. The pump is used to reduce the pressure in the conduit until fluid is induced to flow from the formation. The fluid is typically first discharged into the wellbore. Monitoring equipment is used to determine the quality of the fluid being pumped until the fluid is transferred to a transport vessel or sampling container ("downhole bottle") at some point. The downhole bottle is sealed and then recovered to the surface. At the surface, the downhole bottle is typically transported directly to a laboratory for analysis. Although particularly relevant to the present disclosure, some prior art methods include transferring the sample to another specialized container that is more suitable for laboratory analysis, and may further include removing a small sample for immediate preliminary evaluation.

[0006] The essence of wellbore management is that the wellbore is filled with a special fluid, usually called 'mud'. This fluid is a mixture of chemicals, solids and oil or water. It is designed to maintain a certain pressure gradient so that at any depth in the wellbore, the fluid pressure exceeds the pressure of the reservoir. This prevents the collapse of the wellbore and prevents uncontrolled extraction of reservoir fluid to the surface. The fluid can have additional properties, such as preventing chemical destabilization of the formation material.

[0007] It is known that mud and reservoir fluids include a large amount of gas dissolved in the fluid including acidic gases (such as, H2S). The gas may have many components. When the fluid pressure is reduced to below the bubble point pressure of any one of the gas components, such as when pumped into a formation test tool or downhole bottle, the gas will escape from the solution. This gas can be extracted from the downhole bottle into the above-mentioned special container. In addition, when the mud is at the surface, the gas from the mud itself can be extracted and sampled. The sample gas can be collected from the mud pit where they will be at or near atmospheric conditions.

[0008] An example of such a specialized container is described in US9234822 ("the '822 patent"), the disclosure of which is incorporated herein in its entirety. The container of the '822 patent is a gas sampling device that is constructed of a metal tube with Schrader-type valves positioned on both ends and extending outwardly therefrom. The container of the '822 patent is referred to as a "flow-through" container, in which the container is positioned in the device, a pair of Schrader valves are opened, and sampled gas is introduced into the inlet side of the bottle through one of the valves, flows into the bottle, and flows out through the other valve on the outlet side of the bottle. The Schrader valves are then sequentially actuated to capture a certain amount of gas (i.e., the gas sample) within the container. A known problem with the container of the '822 patent is that mounting the valves to the exterior of the container is susceptible to bending or even breaking during handling and use.

[0009] A known problem with gas sampling containers of the prior art is that in order to safely keep the gas sample in an uncontaminated state, the container must be purged with clean gas before use. This process may be time-consuming and requires a special device to ensure that the container is properly purged. Another problem with gas sampling containers of the prior art is that the entire inner surface of the bottle is exposed to the gas sample and may make the entire sample and / or container non-reusable. Another known problem with Schrader valves (also known as plunger-type valves, in which the plunger interacts with the valve seat to achieve fluid communication) is that they include various materials that may be incompatible with certain gases, and these gases may have a harmful effect on the safety of the valve and the fluid sampling container itself. However, it is also known that Schrader-type valves usually have metal fragments that interfere with the seat surfaces of both the plunger-type valve seat and the polytetrafluoroethylene barrel seal that the valve core uses to seal against the valve body wall. In summary, the valves used in gas sampling containers of the prior art are complex, may include debris, are prone to leakage, and may trap the sampled gas therein.

[0010] It is therefore an object of the present disclosure to have a method and apparatus for obtaining a pressurized or non-pressurized gas sample that minimizes operating time, reduces container complexity, eliminates the need to purge the container, and increases the ability to recycle the container. Another object of the present disclosure is to provide a container with increased reliability so that the gas sample can be safely maintained throughout the process from the transfer point to the laboratory. A further object is to minimize costs by achieving a novel fluid sampling container. Summary of the invention

[0011] One general aspect includes a fluid sample container comprising: a tubular body having a cylindrical wall, a first open end, and a second open end; a first mounting cup sealably connected to the first open end; a second mounting cup sealably connected to the second open end; a first valve assembly positioned in the first mounting cup and adapted for selective fluid communication with the tubular body; and a second valve assembly positioned in the second mounting cup and adapted for selective fluid communication with the tubular body.

[0012] Embodiments may include one or more of the following features. The fluid sample container, in which the first valve assembly includes a first valve housing disposed within the tubular body, a first sealing element disposed between the first valve housing and the first mounting cup, and a first stem at least partially positioned outside the tubular body and coupled to the first valve housing, and the second valve assembly includes a second valve housing disposed within the tubular body, a second sealing element disposed between the second valve housing and the second mounting cup, and a second stem at least partially positioned outside the tubular body and coupled to the second valve housing. The fluid sample container, in which the first valve assembly and the second valve assembly include a spring positioned therein to bias the first valve assembly and the second valve assembly to a closed position. The fluid sample container, in which the first stem is adapted to position the first valve assembly to be in fluid communication with the tubular body in an open position, and the second stem is adapted to position the second valve assembly to be in fluid communication with the tubular body in an open position. The fluid sample container further includes a flexible bag sealably secured to and in fluid communication with one of the first valve assembly and the second valve assembly and positioned within the tubular body. The fluid sample container further comprises a piston assembly sealably slidably positioned within the tubular body, the piston assembly comprising a piston body having a piston outer diameter approximately equal to the tubular inner diameter of the tubular body. The fluid sample container, in which the piston assembly further comprises a sealing element positioned on the piston outer diameter and adapted to fluidically seal a sample gas volume in the tubular body from a buffer gas volume in the tubular body.

[0013] One general aspect includes a method of sampling a fluid, the method comprising: providing a tubular body having a cylindrical wall, a first open end, and a second open end, connecting a first mounting cup to the first open end, connecting a second mounting cup to the second open end, positioning a first valve assembly in the first mounting cup; and positioning a second valve assembly in the second mounting cup. Coupling a fluid source to the first valve assembly; and actuating the first valve assembly and the second valve assembly to an open position, causing fluid from the fluid source to flow through the first valve assembly, into the tubular body, and through the second valve assembly, actuating the second valve assembly to a closed position; and actuating the first valve assembly to a closed position.

[0014] Embodiments may include one or more of the following methods. The method further includes: coupling a fluid source to the first valve assembly; and actuating the first valve assembly and the second valve assembly to an open position to allow fluid from the fluid source to flow through the first valve assembly, into the tubular body and through the second valve assembly; actuating the second valve assembly to a closed position; and actuating the first valve assembly to a closed position. The method further includes: coupling a flexible bag to the first valve assembly and positioning the flexible bag within the tubular body coupling a vacuum source to the first valve assembly and the second valve assembly actuating the first valve assembly and the second valve assembly to an open position to evacuate the tubular body and the flexible bag; and actuating the first valve assembly and the second valve assembly to a closed position. The method further includes: positioning a piston assembly within the tubular body and fluidly sealing a sample gas volume in the tubular body with a buffer gas volume in the tubular body, the piston assembly including a fill port and a check valve assembly for selectively sealing the fill port, coupling a buffer fluid source to the second valve assembly, actuating the first valve assembly and the second valve assembly to an open position, allowing buffer fluid from the buffer fluid source to flow through the second valve assembly and into the tubular body, opening the check valve assembly; allowing fluid to flow through the fill port and through the second valve assembly; and actuating the first valve assembly and the second valve assembly to a closed position.

[0015] One general aspect includes a fluid sample container comprising: a tubular body having a cylindrical wall, a first open end, and a second open end; a first valve housing sealably connected to the first open end; a second valve housing sealably connected to the second open end; a first aerosol valve connected to the first valve housing and adapted for selective fluid communication with the tubular body; and a second aerosol valve connected to the second valve housing and adapted for selective fluid communication with the tubular body.

[0016] A general aspect includes a method for sampling a fluid, the method comprising: providing a tubular body having a cylindrical wall, a first open end, and a second open end, connecting a first aerosol valve having a first actuator to the first open end and in selective fluid communication with the tubular body, connecting a second aerosol valve having a second actuator to the second open end and in selective fluid communication with the tubular body, coupling the first aerosol valve to a fluid source; and depressing the first actuator and the second actuator to supply fluid from the fluid source to the tubular body. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order that the manner in which the above-mentioned features of the present disclosure can be understood in detail, the present disclosure briefly summarized above may be described in more detail by reference to embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the accompanying drawings only illustrate typical embodiments of the present disclosure and are therefore not to be considered as limiting the scope thereof, as the present disclosure may allow for other equally effective embodiments.

[0018] Figure 1 is a cross-sectional exploded view of a fluid sampling container according to certain aspects of the present disclosure.

[0019] Figure 2 is a cross-sectional view of an end portion of a fluid sampling container and a valve assembly according to certain aspects of the present disclosure.

[0020] Figure 3 is a cross-sectional view of a fluid sampling container according to certain aspects of the present disclosure.

[0021] Figure 4 is a cross-sectional exploded view of a fluid sampling container according to certain aspects of the present disclosure.

[0022] Figure 5 is a cross-sectional view of a fluid sampling container according to certain aspects of the present disclosure.

[0023] Figure 6 It is basically cut along plane 4-4 Figure 5 Cross-sectional view of a fluid sampling container.

[0024] Figure 7 According to certain aspects of the present disclosure Figure 6 A cross-sectional view of a fluid sampling container in which the sample bag is in a filled state.

[0025] Figure 8 is a cross-sectional view of a fluid sampling container according to certain aspects of the present disclosure.

[0026] Fig. 9 is a cross-sectional view of a fluid sampling container according to certain aspects of the present disclosure. DETAILED DESCRIPTION

[0027] The present disclosure relates to a pressurized or non-pressurized gas sampling container (gas sampling container) that can be used to collect high-quality fluid samples, including gases and liquids. The gas sampling container includes a novel valve device and a sample delivery device. Certain embodiments of the gas sampling container of the present disclosure further include a bag-in-container device.

[0028] Example of a container for collecting high quality gas samples

[0029] refer to Figure 1, shows an embodiment of a gas sampling container 10 of the present disclosure. The gas sampling container 10 includes a tubular body 11 having a cylindrical wall 12 and a first open end 13 and a second open end 14. It should be understood by those skilled in the art that in this particular embodiment, the first end 13 and the second end 14 can be the same, and either can be used as an inlet or an outlet, or can be both an inlet and an outlet differently, as will be described more fully below. The tubular body 11 can be made of any suitable material (including metals, plastics, and composite materials) that can withstand the pressures expected by the present disclosure, and can be opaque, translucent, or transparent. The gas sampling container 10 includes a valve assembly 15a positioned in the end 13 and a valve assembly 15b external to the end 14.

[0030] Reference now Figure 2, a valve assembly 15a, which is identical to 15b in this embodiment, is shown in detail in a partial cross-sectional view, and includes a hollow valve stem 16, which is sealably positioned within a mounting cup 17 by a sealing element 22 and a valve housing 18. A bell 19 is formed in the outer edge of the mounting cup 17 for assembly to the tubular body 11, as will be described in more detail below. In the illustrated embodiment, the valve housing 18 is in a closed position so that there is no fluid communication through the valve stem 16. The valve assemblies 15a, 15b are similar to aerosol valves, and when the valve stem 16 is depressed or actuated, the valve housing 18 moves to an open position, thereby unsealing the sealing element 22 from its seat against the mounting cup 17 and exposing a port (not shown) in the stem, and thereby enabling direct fluid communication through the valve stem 16 in the open position. The valve housing includes a spring (not shown) to bias the sealing element 22 against the mounting cup 17 when the stem 16 is released, thereby sealing the port in the stem in the closed position. The sealing element 22 may include any suitable element, including an O-ring, etc. These "ported" aerosol valve assemblies 15a, 15b may be made of molded plastic, which is cleaner than the plunger-type valve assembly of the prior art, and does not produce artifacts that interfere with the valve function during the manufacturing process. It has been found that in the embodiments of the gas sampling container disclosed herein, it is advantageous to use valves 15a, 15b because the flow path is free of springs and other components of the prior art valve, which may cause harmful effects as described previously herein. Such ported aerosol valve assemblies 15a, 15b are similar to those known in the art, and an exemplary valve is a continuous pressure valve available from Coster Tecnologie Speciali SpA. Such a valve operates when pressure on the rod 16 causes the valve housing 18 to open and directly communicates with the fluid through the rod. The function of the valve assembly 15a is independent of orientation. There are other types of aerosol valves, and the extent of the aerosol valve contemplated by the present disclosure is as follows: such an aerosol valve without a port overcomes the above-mentioned defects of the plunger valve and seat valve in the prior art.

[0031] Reference again Figure 1 In the illustrated embodiment of the gas sampling container 10, the ends 13, 14 of the cylindrical wall 12 are adapted to receive the bell 19 of the mounting cup 17 to sealably secure the valve assembly 15 to the tubular body 11 by crimping the bell 19 on the ends of the cylindrical wall 12 to form a crimp seal. Although shown as a crimp seal, the present disclosure contemplates other methods of connecting the valve assembly 15 to the tubular member, such as threaded joints, press fits, welding, gluing, and other known sealable attachments, where the joints may be machined, as is done in the case of plastic tubing or thicker wall aluminum tubing. Still referring to Figure 1, the gas sampling container 10 further includes a hollow actuator 20 adapted to be press-fit onto the valve stem 16. In the illustrated embodiment, the actuator 20 further includes threads 21 positioned thereon for securing the adapter to a device (not shown) for filling or emptying the gas sampling container 10. The threads 21 may be any known type of attachment feature, depending on the mating features of the filling or emptying device, and may advantageously be a quick disconnect type, such as a Luer lock type fitting. Once the gas sampling container 10 is assembled as described hereinbefore, the interior volume 25 of the gas sampling container is selectively sealed from the external environment.

[0032] Reference now Figure 3 , shows an alternative embodiment of a gas sampling container 30 of the present disclosure. The gas sampling container 30 includes a tubular body 31 having a cylindrical wall 32 and a first open end 33 and a second open end 34. The tubular body 31 can be made of any suitable material (including metals, plastics and composite materials) that can withstand the pressures expected by the present disclosure, and can be opaque, translucent or transparent. In one embodiment of the present disclosure, the tubular body 31 is made of steel that starts as a flat plate and is then rolled and welded into a tube. This welding forms a seam extending along the vertical length of the tubular body (not shown). The other tubular bodies 31 formed by rolling as described above can be formed by any known method, including machining, extrusion, casting, molding, etc. The ends 33, 34 include curled edges 35, 36 formed by rolling the ends of the tubular body 31. Similar to the gas sample container 10 ( Figure 1 ), the gas sampling container 30 includes a valve assembly 15a positioned in the end 33 and a valve assembly 15b positioned in the end 34. In this particular embodiment, the bell 19 of the valve assemblies 15a, 15b is rolled on the curling edges 35, 36 to form a selectively sealed internal volume. Other sizes and shapes of tubular bodies and sealed housings can be implemented without departing from the scope of the present disclosure. Still other embodiments include an extruded aluminum tubular body including rolled ends to which bells are attached to both ends of the tubular body.

[0033] In operation, and assembled as described above, the gas sampling container 10 can be ready for collecting a gas sample by evacuation or purging. To evacuate the gas sampling container 10, a vacuum source (not shown) is sealably attached to at least one of the actuators 20 of the valve assemblies 15a, 15b, and the actuator is depressed, thereby opening the corresponding valve housing 18 and establishing selective fluid communication with the vacuum source. The vacuum source applies a vacuum for a sufficient amount of time to reduce the pressure within the gas sampling container 10 to a preselected level. At least one actuator 20 is released, thereby closing the valve housing and sealing the gas sampling container 10 at an internal pressure less than the internal pressure of atmospheric pressure.

[0034] In some cases, it will be necessary to purge the interior volume 25 of the gas sampling container 10, as it may initially contain air or other gas, in preparation for the safe introduction of a potentially flammable sample gas. During the purge operation, the interior of the gas sampling container 10 may be flushed with an inert gas, such as argon, to reduce the concentration of oxygen so that a flammable mixture is not formed when a flammable sample gas is allowed to be used. In order to purge the interior volume 25 of the gas sampling container 10, a purge fluid source (not shown) capable of providing an inert gas or other purge fluid is sealably attached to the actuator 20 of the valve assembly 15a, which is depressed to open its corresponding valve housing 18 and establish selective fluid communication with the purge gas source. The actuator 20 of the valve assembly 15b is then depressed to open another valve housing 18, which may or may not be attached to other equipment. The purge gas source introduces purge gas into the interior volume 25 of the gas sampling container 10 through the valve assembly 15a, and the purge gas flows out of the valve assembly 15b for a sufficient amount of time (or volume) to make the interior volume 25 of the gas sampling container 10 safe. The actuator 20 is released, thereby closing the valve housings 15a, 15b and sealing the inert gas within the gas sampling container 10.

[0035] In a sample collection operation, a previously collected gas sample as described above may be collected within the gas sampling container 10 by sealably connecting a sample fluid source of the gas to be sampled (not shown) to the actuator 20 of the valve assembly 15a and sealably connecting a collection system (not shown) to the actuator 20 of the valve assembly 15b. The actuator 20 is then depressed, thereby opening the valve housing 18 and establishing selective fluid communication with the sample fluid source and the collection system. The sample fluid source introduces the sample gas into the interior volume 25 of the gas sampling container 10 through the actuator 20 of the valve assembly 15a, and the sample gas flows out of the actuator 20 of the valve assembly 15b and into the collection system for a sufficient amount of time (or volume) to fill the interior volume 25 of the gas sampling container 10 with the sample gas. The actuator 20 of the valve assembly 15b attached to the collection system is released, thereby closing the valve housing 18. If desired, the pressure of the sample gas source may be increased to provide an overpressure condition within the gas sampling container 10. Once the gas sampling container 10 is filled with sample gas, the actuator 20 of the valve assembly 15a attached to the sample gas source is released, thereby closing the valve housing 18 and sealing the gas sample within the interior volume 25 of the gas sampling container.

[0036] In a sample extraction operation, as described herein directly above, sample gas previously collected within the gas sampling container 10 can be safely extracted for analysis in a laboratory environment. An extraction device (not shown) can be sealably connected to an actuator 20 of the gas sampling container. The actuator 20 is depressed, thereby opening the corresponding valve housing 18 and establishing selective fluid communication with the extraction device. The sample gas is extracted from at least one end of the gas sampling container 10 and provided for laboratory analysis as is known in the art.

[0037] Reference now Figure 4 and Figure 5 , shows another embodiment of the bag-in-tube gas sampling container 50 of the present disclosure. Similar to the description of the gas sampling container 10 previously described herein, the gas sampling container 50 includes a tubular body 11 having a cylindrical wall 12, an open pressure end 53, and an open sample end 54. The tubular body 11 can be made of any suitable material (including metals, plastics, and composite materials) that can withstand the pressures expected by the present disclosure, and can be opaque, translucent, or transparent. The gas sampling container 50 includes a pressure valve assembly 55 sealably positioned in the open pressure end 53, wherein the pressure valve assembly 55 can be the same as described above with respect to the sample end 54. Figure 2 The gas sampling container 50 further includes a bag 56 on the valve assembly, which is sealably disposed in the open sample end 54. The bag 56 on the valve assembly includes a flexible bag 57, which is sealably fixed to the valve assembly 58, wherein the valve assembly 58 can be the same as described above with respect to Figure 2 The valve assemblies 15a, 15b are the same as described above. Such bag on valve assemblies 56 are known in the art, and an exemplary bag on valve is available from Coster Tecnologie Speciali SpA, having a continuous pressure valve as described above. Figure 4 , Figure 5 and Figure 6 , a flexible bag 57 is shown in an unfilled state, wherein the width 60 of the bag is indicated by an arrow. The flexible bag 57 can be constructed of any material that is suitable for being impermeable to the gas to be sampled and that is flexible enough when filled to fill the interior volume 59 of the gas sampling container 50, as will be described more fully below. In addition, although the bag 57 is shown as a rectangle in the unfilled state, it can be circular or other shapes without departing from the present disclosure. In this particular embodiment, the gas sampling container 50 includes an interior of a fixed volume defined by the cylindrical wall 12, the pressure valve assembly 55, and the bag 56 on the valve assembly. The interior of the fixed volume is composed of two independent variable volume compartments. The two variable volume compartments are obviously the volumes of the bag 57 and the interior volume 59. The maximum interior volume is the total interior volume minus the unfilled volume of the bag 57. When the bag 57 is filled, the minimum volume of the interior volume is obviously zero, as will be described more fully below. Similar to reference Figure 1 In the illustrated embodiment of the gas sampling container 10, the end of the cylindrical wall 12 is adapted to receive the bell 19 (or machined edge) of the mounting cup 17 to sealably secure the valve assembly 55, 58 to the tubular body 11 by crimping the bell 19 on the end of the cylindrical wall 12 to form a crimp seal. Similarly, although shown as a crimp seal, the present disclosure contemplates other methods of connecting the valve assembly 55, 58 to the tubular body 11, such as threaded joints, press fits, welding, gluing, and other known sealable attachments. It should be understood that in embodiments where the valve assembly 58 is removably and sealably attached to the tubular body 11, the bag 56 on the valve assembly can be removed after use, and the remaining portion of the gas sampling container 50 can be recycled by reassembling it with the valve on another bag assembly. Also shown in this embodiment are optional valve caps 61, 62, which can cooperate with the threads 21 to seal the ends of the actuator 20 to prevent accidental actuation of the valve housing 18, thereby eliminating accidental release of pressure or gas.

[0038] In operation, the gas sampling container 50 can be prepared for collecting a gas sample by evacuating the internal volume 59. To evacuate the internal volume 59, a vacuum source (not shown) is sealably attached to the actuator 20 on the pressure valve assembly 55, and the actuator is depressed, thereby opening the valve housing 18 and establishing selective fluid communication between the internal volume 59 and the vacuum source. Once the internal volume 59 is evacuated, the valve assembly 55 can be closed and the vacuum source can be disconnected. The internal volume 59 is then maintained under vacuum (relative to atmospheric pressure). In this embodiment, the bag 57 is also evacuated using a vacuum source (not shown) applied to the valve assembly 5, which can occur before or after assembly into the tubular body 11. The valve assembly 58 is disconnected from the vacuum source, and the container 50 is ready to receive a sample. With the internal volume 59 and the bag 57 in the above-described evacuated state, the valve assembly 58 can be attached to the sampling source, and the sample gas can be pulled into the bag by depressing the sample end actuator 20. The vacuum from 59 then "pulls" the sample into the bag. Unlike prior art bag-on-valve assemblies (ie, consumer aerosol cans) where a propellant or pressurized gas is placed in an interior volume, the illustrated embodiment places the interior volume 59 under negative pressure.

[0039] Prior to collecting a gas sample, and with the internal volume 59 and bag 57 evacuated, the bag has Figure 6 The shape and construction shown. As described above, during the process of filling the bag 57 with sample gas, the actuator 20 of the valve assembly 58 is depressed, thereby opening the valve housing 18 and establishing selective fluid communication between the bag 57 and the gas source and the bag 56 on the valve assembly. When the internal volume 59 is in a partial vacuum, it acts as a negative displacement pump together with the bag 57 and, together with the pressure of the sample gas (or, if above atmospheric pressure, the pressure of the internal volume 59), draws the sample gas from the gas source into the bag 57. This negative displacement pumping action is advantageous when the gas source is at or near atmospheric pressure conditions. The sample gas is allowed to flow into the bag 57 for a sufficient amount of time (or volume) to at least partially fill the bag 57, and if the bag is full, the bag will be pressed against the cylindrical wall 12. In this filled state, the bag 57 is at its maximum volume, wherein its outer diameter is the same as the inner diameter of the tubular body 11, and the internal volume 59 is apparently zero, as shown in FIG. Figure 7 After filling is complete, the actuator 20 attached to the valve assembly 58 is released, thereby closing the valve housing 18 and sealing the gas sample within the bag 57. If necessary, the pressure of the gas sample can be increased by providing an external pressure source to the actuator 20 of the valve assembly 55. It will be appreciated by those skilled in the art that in this particular embodiment of the invention, the volume for the sample gas is separate from the internal volume 59, and the sample gas does not contact any inner surface cylindrical wall 12 or cup 17 ( Figure 1). This is particularly important for sampling gases that may interact with certain materials. The interaction of the gas with the inner surface cylindrical wall 12 or cup 17 may damage the structural integrity of the gas sampling container 50 and the gas sample itself. It should be further understood by those skilled in the art that in embodiments where the tubular body 11 is constructed of a transparent material, a visual indication of the fill status of the bag 57 will be apparent. Once the bag 57 is filled, optional end caps 61, 62 may be applied to the actuator 20 to prevent accidental release of the sample gas.

[0040] The negative displacement pumping action of the gas sampling container 50 can be advantageously used in any application where it is necessary to capture a gas sample (especially at relatively low pressures) and maintain its integrity during transportation to a remote location for analysis. Such applications include, but are not limited to, air monitoring, CO2 capture, landfill gas monitoring, human breath studies, and drug and alcohol testing.

[0041] In a sample extraction operation, as described herein directly above, sample gas previously collected within the gas sampling container 50 can be safely extracted for analysis in a laboratory environment. An extraction device (not shown) can be sealingly connected to the actuator 20 of the gas sampling container 50. The actuator 20 of the valve assembly 58 is then depressed, thereby opening the valve housing 18 and establishing selective fluid communication between the bag 57 and the extraction device. The sample gas is extracted from the sample end 54 of the gas sampling container 50 and provided for laboratory analysis as is known in the art. Additionally, and inventively, the sample gas contents of the bag 57 can be completely extracted by applying a positive pressure through the valve assembly 55 and into the interior volume 59.

[0042] Reference now Figure 8 and Fig. 9 , shows an embodiment of the gas sampling container 70 of the present disclosure. Similar to the gas sample container 10 ( Figure 1), the gas sampling container 70 includes a tubular body 71 having a cylindrical wall 72 and a first open end 73 and a second open end 74. It will be appreciated by those skilled in the art that in this particular embodiment, the first end 73 and the second end 74 may be identical, and either may be used as an inlet or an outlet, or may be both an inlet and an outlet differently, as will be described more fully below. However, it should be noted that the initial position of the piston assembly 75 will determine the flow direction from 15a to 15b or from 15b to 15a for collecting gas samples. The gas sampling container 70 includes a valve assembly 15a positioned in the end 73 and a valve assembly 15b positioned in the end 74. The gas sampling container 70 further includes a piston assembly 75 slidably positioned within the interior of the tubular body 71. The piston assembly 75 includes a piston body 76, a seal 77, a filling port 79, and a check valve assembly 78. The check valve assembly 78 is shown as a flapper valve type check valve, but may include any known check valve that can provide selective fluid communication between volumes. The check valve assembly 78 is used to open the Figure 8 ) allows fluid to flow through the fill port 79 into the buffer gas volume 81 in the fill direction 83 and in the closed position ( Fig. 9 ) prevents fluid from flowing through fill port 79 into sample gas volume 80 in a pressurizing direction 84. Piston body 76 is cylindrical in shape with a piston outer diameter slightly smaller than the inner diameter of tubular body 71, and includes features for receiving seal 77. Piston assembly 75 is sealingly slidably positioned within tubular body 11. In some embodiments, seal 77 comprises an O-ring configured and sized to slidably and fluidly seal sample gas volume 80 from buffer gas volume 80 when check valve assembly 78 is in the closed position, as will be described more fully below.

[0043] .exist Figure 8 and Fig. 9In the illustrated embodiment, the gas sampling container 70 includes a fixed volume interior defined by a cylindrical wall 72 and a piston assembly 75. The fixed volume interior is composed of two independent variable volume compartments. The two variable volume compartments are a sample gas volume 80 and a buffer gas volume 81. In a sample collection operation, a previously collected gas sample as described above can be collected in the gas sampling container 70 by sealably connecting a source of gas to be sampled (not shown) to the actuator 20 of the valve assembly 15a and sealably connecting a pressurizing system (not shown) to the actuator 20 of the valve assembly 15b. The actuator 20 is then depressed, thereby opening the valve housing 18 and establishing selective fluid communication with the sample fluid source and the pressurizing system. The pressurizing system is configured to change the pressure of the buffer volume 81 from a partial vacuum pressure to a predetermined level of pressure above atmospheric pressure. The gas source introduces the sample gas into the sample gas volume 80 of the gas sampling container 70 through the actuator 20 of the valve assembly 15a, and the sample gas flows through the filling port 79 of the piston assembly 75 and the check valve assembly 78 and flows out of the actuator 20 of the valve assembly 15b and into the pressurized system. It should be understood by those skilled in the art that the introduction of the sample gas in the filling direction 83 pushes the piston assembly 75 in the filling direction, thereby increasing the sample gas volume 80 and reducing the buffer volume 81.

[0044] The sample gas is allowed to flow in a filling direction 83 for a sufficient amount of time (or volume) to fill the sample gas volume 80 of the gas sampling container 70 with the sample gas. The actuator 20 of the valve assembly 15a attached to the sample gas source is released, thereby closing the valve housing 18 and closing the check valve assembly 78. In certain embodiments, the pressure of the sample gas source can be increased to provide an overpressure condition within the gas sampling container 70 by introducing a buffer fluid from a pressurized source into the valve assembly 15b, wherein the pressurized source will contain a buffer fluid source. It will be appreciated by those skilled in the art that when the check valve assembly 78 is in the closed position ( Fig. 9 ), the introduction of buffer fluid in the buffer direction will push the piston assembly 75 to slide in the filling direction 84 and increase the buffer volume 81 and reduce the sample gas volume 80, thereby increasing the pressure of the sample gas. The check valve assembly 78 is selected to provide a sufficiently large closing bias force to maintain a predetermined amount of pressure differential between the sample gas volume 80 and the buffer volume 81, thereby preventing the check valve from leaking during subsequent transportation and other operations of the gas sample container 70. Once the gas sampling container 70 is filled with sample gas and buffer fluid, the actuator 20 of the valve assembly 15b attached to the pressurization system is released, thereby closing the valve housing 18 and sealing the gas sample within the sample gas volume 80 of the gas sampling container.

[0045] In a sample extraction operation, as described herein directly above, sample gas previously collected within the gas sampling container 70 can be safely extracted for analysis in a laboratory environment. An extraction device (not shown) can be sealingly connected to the actuator 20 of the valve assembly 15a of the gas sampling container 70. An optional pressurizing system (not shown) can be connected to the actuator 20 of the valve assembly 15b. The sample gas can be extracted from the valve assembly 15a by coordinating the extraction device and the pressurizing system to push the piston assembly 75 in the filling direction 84 to expel the sample gas from the sample volume 80 and into the collection device.

[0046] Although the foregoing relates only to certain embodiments of the present disclosure, certain observations should be made as to the breadth of the present disclosure. Other and further embodiments of the present disclosure may be devised without departing from the basic scope of the present disclosure, and the scope of the present disclosure is determined by the appended claims.

Claims

1. A method for sampling a fluid, the method comprising: providing a tubular body having a cylindrical wall, a first open end, and a second open end; connecting a first mounting cup to the first open end, the first mounting cup having a seat disposed on an inner surface thereof; connecting a second mounting cup to the second open end, the second mounting cup having a seat disposed on an inner surface thereof; positioning a first valve assembly in the first mounting cup, the first valve assembly having a sealing element that seals against the seat in a closed position; as well as positioning a second valve assembly in the second mounting cup, the second valve assembly having a sealing element that seals against the seat in a closed position; coupling a flexible bag to the first valve assembly and positioning the flexible bag within the tubular body; coupling a vacuum source to the first valve assembly and the second valve assembly; depressing the first valve assembly and lifting the sealing element from the seat to an open position; depressing the second valve assembly and lifting the sealing element from the seat to an open position; evacuating the tubular body and the flexible bag; releasing the second valve assembly and biasing the sealing element against the seat to the closed position; releasing the first valve assembly and biasing the sealing element against the seat to the closed position; coupling a fluid source to the first valve assembly; actuating the first valve assembly to the open position and actuating the second valve assembly to the open position; drawing fluid from the fluid source through the first valve assembly and into the flexible bag; as well as The first valve assembly is actuated to the closed position and the second valve assembly is actuated to the closed position.

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