Hermetically sealed sample disc and device for unsealing sample disc

Abstract

An apparatus (140, 170) for unsealing a sample disc (130) for a thermal analysis instrument, the apparatus comprising a sample disc holder, an actuator element and a stamping element (144, 174). The sample disc holder is configured to secure the sample disc (130) in a fixed position relative to the sample disc holder. The actuator element is fixed to the sample disc holder and is formed of a heat-sensitive material that changes the shape of the actuator element in response to a change in the external temperature to the transition temperature. A stamping element (144, 174) is attached to the actuator element and positioned relative to the sample tray (130) such that a change in shape of the actuator element in response to a change in external temperature moves the stamping element (144, 174) to pierce the sealing element (138) on the sample tray (130), thereby exposing the internal volume of the sample tray (130) to the external environment.

Description

Related Applications

[0001] This application claims the benefit of earlier filing date of U.S. Provisional Patent Application Serial No. 63 / 466,447 filed May 15, 2023, and entitled “Hermetically Sealed Sample Pan and Device for Unsealing Same,” the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The disclosed technology relates to thermal analysis of sample materials. More specifically, the present technology relates to a sample pan for a thermal analysis instrument and a device for unsealing a sealed sample pan. BACKGROUND

[0003] In thermal analysis, a sample to be evaluated is placed in a container, such as a sample pan, which is then placed in a thermal analysis instrument. The interior environment of the instrument is typically purged with an inert gas. For some experiments, the sample pan is sealed to prevent the sample from being exposed to air and moisture prior to the start of the experiment. Then, just prior to loading the pan into the instrument, the seal is pierced or otherwise opened or removed. During this process, there is a period of time in which the sample is exposed to the surrounding air. This period of time begins when the seal is first broken and the pan is loaded into the instrument until the instrument is closed and the interior environment is fully purged with the inert gas. For some samples, this period of exposure can be detrimental to the results of the experiment.

[0004] To address the above issues, thermal analysis instruments are often located within a glovebox. Sample preparation is performed within the glovebox, so the sample exposure is limited to the glovebox environment, which typically contains an inert gas. The glovebox limits the amount of oxygen and moisture present in the environment. While reducing exposure to the indoor environment, the glovebox can require a large volume to accommodate the instrument. Additionally, if the glovebox is needed for other purposes, sharing the glovebox can limit the time the glovebox can be used for thermal analysis experiments. Alternatively, the glovebox can be dedicated to the thermal analysis instrument; however, other uses of the glovebox would require an additional unit, which means additional cost. SUMMARY

[0005] In one aspect, a sample pan for a thermal analysis instrument includes a pan body and a sealing element. The pan body has an interior volume for receiving a sample and a gas path extending from the interior volume to an outer surface of the pan body. The sealing element is disposed in the gas path to obstruct the gas path, thereby sealing the interior volume from an external environment. The sealing element includes a heat-sensitive material that changes a shape of the sealing element in response to a change in a temperature of the external environment to a transition temperature. The change in the shape exposes the interior volume to the external environment through the gas path.

[0006] The sealing element can include a plug made of a shape memory material, such as a shape memory metal, alloy, or polymer. The shape memory material can be a two-way shape memory material.

[0007] The sealing element can be disposed on an outer surface of the pan body at an end of the gas path. The sealing element can be a sealing ring disposed between inner surfaces of the pan body. The pan body can have a circumferential wall having a passage therein, and the sealing element can be a sealing ring disposed on an outer surface of the circumferential wall.

[0008] The sealing element can include a plug made of a material having a melting temperature at the transition temperature. The sealing element can include a metal plug having a surface with a meltable layer formed thereon.

[0009] The sealing element can include a plug disposed in the gas path and an actuator element coupled to the plug. The actuator can be made of a shape memory metal and have a shape that changes in response to a change in a temperature of the external environment to a transition temperature. The change in the shape of the actuator element removes the plug from the gas path. The shape memory metal can be a two-way shape memory metal. The actuator element can be a spring made of a shape memory metal.

[0010] The change in the temperature of the external environment to the transition temperature to expose the interior volume to the external environment can be an increase in temperature or a decrease in temperature.

[0011] The pan body can include a plurality of pan body portions secured to each other.

[0012] The sample pan can hold a sample during a measurement by the thermal analysis instrument, and the transition temperature can be lower than a lowest temperature in a measurement temperature range.

[0013] In another aspect, a method for preparing a sample for a thermal analysis instrument includes loading a sample into an interior volume of a sample pan. The sample pan has a gas path from the interior volume through the sample pan to an external environment. The sample is sealed in the sample pan by a sealing element that blocks the gas path from the interior volume to the external environment. The sealing element contains a heat-sensitive material that changes a shape of the sealing element in response to a change in a temperature of the external environment to a transition temperature. The method continues with loading the sample pan into the thermal analysis instrument and operating the thermal analysis instrument to change the temperature of the external environment of the sample pan to at least the transition temperature. The change in shape removes the blockage from the gas path so that the interior volume is in communication with the external environment.

[0014] The external environment can be defined inside the thermal analysis instrument, and the method can further include purging the external environment with a user-selected gas after the step of loading the sample pan and before the step of operating the thermal analysis instrument to change the temperature of the external environment.

[0015] Operating the thermal analysis instrument can include raising or lowering the temperature of the external environment of the sample pan. Operating the thermal analysis instrument can include changing the temperature within a measurement temperature range that does not include the transition temperature.

[0016] In another aspect, an apparatus for unsealing a sample pan for a thermal analysis instrument includes a sample pan holder, an actuator element, and a punch element. The sample pan holder is configured to secure a sample pan in a fixed position relative to the sample pan holder. The actuator element is secured to the sample pan holder and is formed of a heat-sensitive material that changes a shape of the actuator element in response to a change in an external temperature to a transition temperature. The punch element is attached to the actuator element and is disposed at a position relative to the sample pan such that a change in the shape of the actuator element that occurs in response to the change in the external temperature moves the punch element to pierce a sealing element. Piercing of the sealing element exposes an interior volume of the sample pan to an external environment.

[0017] The actuator element can be a coil spring made of a shape memory metal. The change in the shape of the actuator element can be a change in a length of the coil spring.

[0018] The actuator element can be a helical coil made of a shape memory metal. The change in the shape of the actuator element can be a change from a non-planar configuration to a planar configuration of the helical coil.

[0019] In another aspect, a method for preparing a sample for a thermal analysis instrument includes securing a sample pan in a device for unsealing the sample pan. The device includes a sample pan holder, an actuator element, and a punch element. The sample pan holder is configured to secure the sample pan in a fixed position relative to the sample pan holder. The actuator element is secured to the sample pan holder and is formed of a heat-sensitive material that changes the shape of the actuator element in response to a change in an external temperature to a transition temperature. The punch element is attached to the actuator element and is disposed at a position relative to the sample pan such that a change in the shape of the actuator element that occurs in response to a change in the external temperature moves the punch element to pierce a sealing element on the sample pan, thereby exposing an interior volume of the sample pan to an external environment. The method further includes loading the device into a thermal analysis instrument, and changing a temperature of the thermal analysis instrument to the transition temperature to change the shape of the actuator element. As a result, the punch element moves to pierce the sealing element.

[0020] The actuator element can be a helical spring, and the change in the shape of the actuator element can be a change in a length of the helical spring.

[0021] The actuator element can be a helical coil, and the change in the shape of the actuator element can be a change from a non-planar configuration to a planar configuration of the helical coil. BRIEF DESCRIPTION OF DRAWINGS

[0022] The above-recited advantages and other advantages of the present application will become further apparent to those skilled in the art from the following descriptions, taken in conjunction with the associated drawings. Like reference numerals in the figures indicate like structural elements and features in various figures. For clarity, not every element is labeled in every figure. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the application.

[0023] FIG. 1A is an exploded view of an example of a sample pan for a thermal analysis instrument, and FIG. 1B and FIG. 1C are cross-sectional views of the sample pan in a hermetically sealed state and an unsealed state, respectively.

[0024] FIG. 2A and FIG. 2B are cross-sectional views of the sample pan shown in a hermetically sealed state and an unsealed state, respectively, and having a plug that includes a layer of meltable material.

[0025] FIG. 3A and FIG. 3B are cross-sectional views of the sample pan in a hermetically sealed state and an unsealed state, respectively, utilizing a shape memory metal plug as a sealing element.

[0026] FIG. 4A and FIG. 4Bare cross-sectional views of a sample pan in a hermetically sealed state and an unsealed state, respectively, utilizing a seal element in the form of a sealing ring.

[0027] FIG. 5A and FIG. 5B are cross-sectional views of a sample pan in a hermetically sealed state and an unsealed state, respectively, utilizing a shape memory metal actuator and a sealing plug.

[0028] FIG. 6A and FIG. 6B are cross-sectional views of a sample pan in a hermetically sealed state and an unsealed state, respectively, utilizing a shape memory metal spring and a sealing plug.

[0029] FIG. 7A and FIG. 7B are cross-sectional views of a sample pan in a hermetically sealed state and an unsealed state, respectively, and FIG. 7C is a perspective view of a sample pan in an unsealed state, wherein the sample pan utilizes a bi-directional shape memory metal sealing ring.

[0030] FIG. 8 is a flowchart representation of an example of a method for preparing a sample for a thermal analysis instrument.

[0031] FIG. 9 is an example of a hermetically sealed sample pan that can be used with a thermal analysis instrument.

[0032] FIG. 10A and FIG. 10B are a side view and a cross-sectional perspective view of a sample pan in a device for unsealing the sample pan, respectively.

[0033] FIG. 11A to FIG. 11D is a perspective view and a cross-sectional view of another example of a sample pan in a device for unsealing the sample pan.

[0034] FIG. 12 is a flowchart representation of another example of a method for preparing a sample for a thermal analysis instrument. DETAILED DESCRIPTION

[0035] Reference throughout this specification to "an embodiment" or "an example" means that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present teachings. The appearances of the phrases "in one embodiment" or "an example" in various places in the specification are not necessarily all referring to the same embodiment or example.

[0036] The present teachings will now be described in detail by referring to exemplary embodiments or examples of the present teachings as illustrated in the accompanying drawings. While the present teachings are described in conjunction with various embodiments and examples, it will be understood that the present teachings are not limited to such embodiments and examples. On the contrary, the present teachings cover various alternatives, modifications, and equivalents, as will be appreciated by those skilled in the art. Additional specific embodiments, modifications, and embodiments within the scope of the present disclosure as described herein will be recognized by those of ordinary skill in the art having the benefit of the teachings herein. Such additions, modifications, and embodiments are to be considered within the scope of the present teachings.

[0037] Briefly, the embodiments and examples disclosed herein relate to a sample pan for a thermal analysis instrument and a device for unsealing the sample pan. The sample pan includes a sealing element that is opened by controlling the temperature of the instrument when the sample pan is inside the instrument. Typically, the sample pan is loaded with a sample to be tested while the sample pan is in an inert gas environment. The sample pan is then sealed in the inert gas environment, then removed from the inert environment and loaded into the instrument, after which the instrument is closed and the environment inside the instrument is purged. Once the desired instrument environment is reached, the instrument temperature is changed to just above the transition temperature of the sealing element, such that the sample pan is unsealed to expose the sample to the instrument environment. Alternatively, the device for unsealing the sample pan includes an actuator element that changes shape at the transition temperature, such that a punch element coupled to the actuator element moves to pierce the sealing element and expose the sample. After either specific implementation, the instrument is operated to acquire measurement data of the sample over a range of temperature ranges.

[0038] As used herein, a “thermal analysis instrument” refers to an instrument used to determine one or more properties of a sample as a function of temperature. As non-limiting examples, the thermal analysis instrument can be a thermogravimetric analyzer (TGA) or a differential scanning calorimeter (DSC). A “sample pan” refers to a container that holds a sample for measurement by a thermal analysis instrument. The sample pan can have a variety of shapes, and can include a pan body formed as a single part or body. Alternatively, the sample pan can include two or more pan body parts that are secured to one another to form the sample pan.

[0039] The term “gas path” is used herein to refer to a defined path between two regions through which a gas or gas mixture is able to pass. For example, the gas path can be defined by one or more channels (e.g., openings) in or through a solid body, such that an environment at one end of the gas path is in communication with and exposed to an environment at the other end of the gas path through the channels.

[0040] "Shape memory material" refers to a metal, alloy, or polymer that can deform upon cooling but will return to its original shape (i.e., its memory shape) when heated to a sufficient temperature (i.e., a temperature equal to or greater than the transition temperature). As used herein, "transition temperature" refers to the temperature at which the shape of a component formed from a shape memory material changes. The transition temperature can be altered by changing the material composition of the shape memory material.

[0041] The examples provided below primarily concern shape memory metals and alloys; however, it should be recognized that in some specific implementations, shape memory polymers may be used alternatively, depending on factors such as temperature and shape change considerations. Non-limiting examples of shape memory metals include nickel-titanium and copper-aluminum-nickel. Shape memory material components described herein can exhibit either a unidirectional or bidirectional shape memory effect. For unidirectional shape memory materials, a component heated to or above its transformation temperature changes its deformed shape from its lower temperature to its memory shape; however, subsequent cooling below the transformation temperature does not cause the component to revert to its deformed shape. For bidirectional shape memory metals, a component changes from a first memory shape to a second memory shape when heated to or above its transformation temperature and reverts to its first memory shape when cooled below the transformation temperature. The embodiments described herein can utilize shape memory metal components exhibiting either effect.

[0042] FIG. 1A This is an exploded view of an example of a sample tray 10 used in a thermal analysis instrument. FIG. 1B and FIG. 1C These are cross-sectional views of the sample tray 10 in an airtight sealed state and an unsealed state, respectively.

[0043] The sample tray 10 includes a lower tray 12 and an upper tray 14, which can be secured to each other after a sample is loaded into the lower tray 12. In one embodiment, the lower tray 12 and the upper tray 14 are made of stainless steel. In some non-limiting alternative embodiments, the trays 12, 14 are made of gold, aluminum, copper, ceramic, or quartz. An optional gasket 16 may be included to improve the hermetic seal. The gasket 16 may be a gold-plated copper gasket or a gasket formed of a soft metal such as gold, silver, copper, or aluminum. The trays 12, 14 may be attached to each other via complementary threaded portions.

[0044] The lower disk 12 and upper disk 14, when attached, define a disk with an internal volume that includes the sample to be tested. An opening 18 in the upper disk 14 defines a gas path extending from the internal volume to the outer surface 22. When the sample disk 10 is in a hermetically sealed state ( FIG. 1BA sealing element 24 disposed in the opening 18 blocks (i.e., obstructs) the gas path. Therefore, the sample is not exposed to the external environment of the sample tray 10. The sealing element 24 may partially or completely occupy the length of the opening 18, and in some alternative embodiments, the sealing element 24 extends outward from one or both ends of the opening 18.

[0045] The sealing element 24 is formed of a thermosensitive material that changes shape in response to temperature changes. The shape change occurs when the temperature rises or falls to the transition temperature of element 24. When the temperature of the external environment (which is the internal environment of the instrument when the sample tray resides in the thermal analyzer) reaches the transition temperature, the shape change of the sealing element 24 partially or completely removes the blockage in opening 18, exposing the sample to the external environment. In one embodiment, the sealing element 24 is a plug made of metal or other material having a transition temperature defined as the melting temperature of the material. Therefore, the melting of the plug and the resulting change in its shape release the plug from opening 18 by gravity.

[0046] The partially or fully melted plug 24 is captured by a cup 26 positioned below the bottom of the opening 18. In the example shown, the cup 26 is integral with the rest of the upper disc 14. The gas path between the internal volume and the external environment includes the opening 18 (e.g., a vertical hole) 18 blocked by the plug 24, and also includes horizontal channels 28A and 28B in the region of the upper disc 14 extending downward toward the cup 26. When the plug 24 is released and falls below the horizontal channels 28 and into the cup 26, the opening 18 is unobstructed, and the internal volume communicates with the external environment. In embodiments without a cup, the molten plug falls onto the bottom inner surface of the lower disc 12.

[0047] The transition temperature at which the solid stopper 24 melts is selected to be above the ambient temperature of the thermal analysis instrument and the temperature range of the environment in which the sample tray 10 is loaded (e.g., a glove box). Additionally, the transition temperature is below the lowest temperature within the instrument's measurement temperature range during sample measurement. After the sample tray 10 is loaded into the instrument and the internal environment is purged, the internal temperature is raised to equal to or above the transition temperature while remaining below the lowest temperature within the measurement temperature range. Therefore, the sample can be exposed to the purged environment before initiating a temperature ramp for sample measurement. The purged environment may include one or more inert gases, such as argon and nitrogen.

[0048] In relation to FIG. 1A to FIG. 1CIn alternative configurations to those described, the stopper may be formed of a material whose shape does not change with temperature; however, in such a configuration, the stopper includes a layer of material that melts at the transition temperature. For example, the stopper may be a metallic stopper 30, such as a stainless steel stopper, whose at least one surface is coated with a layer 32 of a fusible material (such as a low-melting-point alloy), such as... FIG. 2A As shown. The stopper 30 is cylindrical, and its dimensions are set to facilitate passage through the opening 18; however, when a layer of fusible material 32 is coated on its curved surface, the coated stopper is larger than the opening 18 and is pressed into the opening 18 to form an airtight seal. In another embodiment, the stopper is conical, wider at the top than at the bottom, and a portion of the stopper extends above the top of the opening 18. In other embodiments, additional surfaces of the stopper or the entire stopper may be coated. Referring again to the example shown, during melting, the effective reduction in the diameter of the coated stopper is reduced, allowing the metal stopper 30 to be released into the cup 26.

[0049] FIG. 3A and FIG. 3B These are cross-sectional views of the sample tray 40 in its airtight and unsealed states, respectively. The sample tray 40 can be structurally similar to... FIG. 1A to FIG. 1C The sample tray 10; however, the sealing element is a shape memory metal plug 42. FIG. 3A In this configuration, the stopper 42 is shaped like a "disc," with the diameter of its top larger than that of its base. When the internal temperature of the thermal analysis instrument rises to the transition temperature or slightly above, the shape of the stopper 42 changes to its "memory" shape, such as... FIG. 3B As shown, the diameter of the top of the stopper 42 decreases. Therefore, the stopper 42 falls from the upper disc 14 into the cup 26. It will be appreciated that in other embodiments, the geometry of the orifice and the stopper can differ to allow the stopper 42 to be released under sufficient heating. The stopper 42 can have different shapes, as long as the initial shape allows the stopper 42 to completely block the orifice and the altered shape allows the stopper 42 to fall into the cup 26 by gravity.

[0050] exist FIG. 4AIn another example shown, a cross-sectional view of a sample tray 50 in a hermetically sealed state is illustrated. The sample tray 50 includes a lower tray 52 and an upper tray 54 having a channel 56. The channel 56 provides a gas path from the inside to the outside of the upper tray 54. In an alternative embodiment, two or more channels may exist through the upper tray 54. Before the lower tray 52 and upper tray 54 are attached to each other, the inner surface 58 of the lower tray 52 receives the sample during the sample loading process. A sealing element 60 in the form of a sealing ring extends from the top surface 62 of the lower tray 52 to the inner surface 64 of the upper tray 54. The sealing ring 60 is made of shape memory metal, which changes to a "memory shape" once the temperature rises to at least its transition temperature. The internal volume capable of containing the sample for evaluation is defined by the lower tray 52, the sealing ring 60, and the upper tray 54. The sealing ring 60 is shaped with thin cylindrical walls and prevents the internal volume from communicating with the external environment through the channel 56.

[0051] When the temperature of the external environment reaches or exceeds the transition temperature, the shape of the sealing ring 60 changes to its memory shape, such as... FIG. 4B As shown, the sealing ring 60 collapses (i.e., buckles radially outward), reducing its height to create a gap between the top of the sealing ring 60 and the inner surface 64 of the upper disk 54. This gap allows the internal volume to communicate with the external environment through a gas path above the top of the sealing ring 60 and to the outside through channel 56. Therefore, the change in shape of the sealing ring 60 causes the sample disk 50 to open.

[0052] In another example, FIG. 5A The provided cross-sectional view shows a sample disk 70 in an airtight sealed state. The sample disk 70 includes a lower disk body 72, an upper disk body 74 having an opening between an inner surface 76 and an outer surface 78, a sealing plug 80, and an actuator element 82. The sides of the opening are tapered to receive and engage with the tapered sides of the sealing plug 80. The actuator element 82 is a shape memory metal component in the shape of an arcuate plate, having a convex lower surface and a concave upper surface. The actuator element 82 is held in place by a groove 84 in the upper disk body 74 that captures the end of the element. The sealing plug 80 is coupled to the center of the actuator element 82 and positioned within the opening. Therefore, the internal volume defined between the lower disk body 72 and the upper disk body 74 is sealed by the sealing plug 80.

[0053] Increasing the temperature of the external environment to equal or exceed the transition temperature will cause the actuator element 82 to return to its "memory" shape, such as FIG. 5B As shown. This shape change causes the sealing plug 80 to be lifted upwards and disengaged from the opening. As a result, a gap is formed along the opening between the side of the sealing plug 80 and the surface of the upper disk 74. Therefore, lifting the sealing plug 80 achieves the opening of the sample disk 70.

[0054] FIG. 6A and FIG. 6B Cross-sectional views of another example of a sample tray 90 in both hermetically sealed and unsealed states are shown. In this example, the sample tray 90 includes a lower tray 92, an upper tray 94, and a sealing plug 96. The upper tray 94 includes an aperture closed at its lower end. A pair of horizontal channels 98A and 98B are formed in the upper tray 94 to allow the internal volume to communicate with the external environment. A shape memory metal spring 100 is disposed in the aperture such that one end abuts against the bottom of the aperture while the other end contacts the sealing plug 96. FIG. 6A In this configuration, the sealing plug 96 is positioned to block the gas path defined by the lower channel 98A, the orifice, and the upper channel 98B. Once the transition temperature of the spring 100 is reached or exceeded, the spring 100 returns to its extended shape, as... FIG. 6B As shown. This expansion of the spring 100 causes the sealing plug 96 to move to a higher position in the orifice, thereby removing the gas path blockage and opening the sample tray 90.

[0055] FIG. 7A and FIG. 7B A perspective view and a cross-sectional perspective view of another example of a sample tray 110 in an airtight state are shown. FIG. 7C A perspective view of a sample tray 110 in an unsealed state is shown. The sample tray 110 includes a lower tray 112 and an upper tray 114, which together define an internal volume comprising the loaded sample. The lower tray 112 partially includes a circumferential wall 116 and a gas path in the form of a channel 118 in the wall 116 to expose the internal volume to the external environment. In other examples, multiple channels through the wall 116 may be provided. The sample tray 110 also includes a sealing ring 120 made of bidirectional shape memory metal, which is “trained” to actuate (change shape) from a first memory shape to a second memory shape when heated to a transition temperature, and to revert to the first memory shape when cooled below the transition temperature. It should be appreciated that the transition temperature during heating may differ from the transition temperature during cooling, or may be similar but different due to hysteresis. The sealing ring 120 may be "C-shaped" such that there is a gap 122 between the two ends, although in an alternative embodiment, the ring may be continuous, i.e., there is no gap.

[0056] During sample mounting in the TGA system, the sealing ring 120 is positioned above channel 118 and cooled to a lower transition temperature to secure it in place on the lower disk 112, after which the sample is loaded and the lower disk 112 and upper disk 114 are secured to each other. In an alternative loading process, the sample is loaded before the sealing ring 120 is placed in place and subsequently secured in place by cooling, and then the lower disk 112 and upper disk 114 are secured together. Before starting the measurement, the sample disk 110 is heated to at least the transition temperature within the thermal analyzer to cause the sealing ring 120 to expand to a larger inner diameter. As a result, the sealing ring 120 falls to the base of the lower disk 112, and the sample disk 110 is opened. It should be noted that a reverse thermal process can be used, employing a suitable shape memory material, in which the sealing ring 120 is positioned above channel 118 and then heated to secure it in place. The sealing ring 120 is then released from its position to open the sample tray 110 by cooling. In some specific implementations, such as for TGA instruments that do not have the necessary cooling capacity to open the sample tray 110, this reverse process may be impractical.

[0057] In an alternative embodiment, the sealing ring 120 may be made of unidirectional shape memory metal. To seal the sample tray 110, the sealing ring 120 is positioned above the channel 118 and manually compressed into place. After the sample tray 110 is loaded into the thermal analysis instrument, the instrument's operating temperature is increased as described above to open the sample tray 110.

[0058] FIG. 8 This is a flowchart representation of an example of a method 200 for preparing a sample for a thermal analysis instrument. In some embodiments, method 200 is performed using one of the sample trays described above, but other sample trays with appropriate configurations may also be used.

[0059] The method includes loading a sample (210) from an inert chamber (glove box) into the internal volume of a sample tray. The sample tray may be made of a lower tray and an upper tray, which define the internal volume when fixed to each other. Loading the sample may include placing the sample in the lower tray before fixing the upper tray to the lower tray. A gas path through the sample tray is blocked (220) to prevent a continuous path between the internal volume and the external environment. In some embodiments, the gas path blocking (220) is performed before loading the sample into the internal volume. For example, a sealing element may be positioned in or on the upper tray to block the gas path passage before the lower and upper trays are attached to each other.

[0060] Method 200 continues with the following steps: the loaded and sealed sample tray is removed from the glove box and loaded (230) into the thermal analyzer. The instrument is then operated (240) to control the temperature of the environment surrounding the sample tray (i.e., the external environment), and then the temperature is changed to a transition temperature at which the shape of the sealing element changes. This shape change at least partially removes obstructions in the gas path, thereby opening the sample tray and allowing the internal volume to communicate with the external environment. Once the sample tray is opened and exposed to the controlled gas and temperature environment of the thermal analyzer, the instrument can be operated to perform sample measurements over a range of temperatures.

[0061] In the examples above, the gas path takes the form of an opening or other channel, and may include one or more channel segments to allow the internal volume to communicate with the external environment. It will be appreciated that the gas path can take other structural configurations. For example, the cross-sectional area along the length of the opening need not be circular, and the cross-sectional dimensions and shape can vary along the length of the opening or channel.

[0062] In contrast to the sample tray described above, sample tray 130 can be... FIG. 9 The sample tray 130 is nominally shaped as a cup or other receiver with an opening at the top. The sample tray 130 comprises an integral unit having a base 132, cylindrical sidewalls 134, and a flange 136 extending outward and away from the cylindrical sidewalls 134. As described above in conjunction with other embodiments of the sample tray, the internal volume of the sample tray 130 is adapted to receive a sample to be tested. The internal volume is defined as the area surrounded by the base 132, the cylindrical sidewalls 134, and a sealing element 138 attached to the flange 136. The sealing element 138 hermetically seals the internal volume. In some embodiments, the sealing element is a foil. As a non-limiting example, the foil may be gold foil or aluminum foil.

[0063] FIG. 10A and FIG. 10B These are a side view and a cross-sectional perspective view of a sample tray 130 held in a device 140 for opening the sample tray by piercing a sealing element 138. FIG. 10A The sample tray 130 is shown inserted into the device 140 and kept in a sealed state, while FIG. 10B The device 140 is shown in a modified state, which enables the sealing element 138 to be punctured, thereby exposing the sample in the internal volume to the external environment.

[0064] The device 140 includes a sample tray holder configured to hold a sample tray 130 in a fixed position. The device 140 also includes an actuator element and a stamping element 144. In the illustrated embodiment, the actuator element is a helical spring 142 made of shape memory metal. The sample tray holder includes a base 146 and a handle 148. The base 146 has an opening to allow the cylindrical sidewall 134 of the sample tray 130 to pass through when the flange 136 is positioned against the top surface of the base 146. In some embodiments, the base 146 and the handle 148 may be made of sheet metal pressed or bent into its final form. The holder 150 is secured to the base 146 by a tab 152 formed in the base. The holder 150 includes a holder extension 154 shaped to engage and secure a lower portion of the helical spring 142.

[0065] As in FIG. 10B As seen more clearly, the stamping element 144 includes a lower portion comprising an outwardly flared section 156, a vertically extending intermediate section 158, and an upper section divided into two arms 160, which are horizontally bent at their ends. The two arms 160 engage a helical spring 142 near their upper ends, thereby connecting the stamping element 144 to the helical spring 142 such that changes in the shape of the helical spring 142 (e.g., expansion or contraction of its length) cause changes in the vertical position of the helical pin 142, thereby moving the stamping element 144 in the vertical direction.

[0066] In use, the device 140 and the sealed sample tray 130 are loaded into the thermal analysis instrument for sample measurement. When the temperature of the external environment (i.e., the internal temperature of the thermal analysis instrument) reaches the transformation temperature of the shape memory metal, the helical spring 142... FIG. 10A The extended shape shown changes to FIG. 10B The compact shape is shown. During this shape change, the stamping element 144 is forced downward. The opening section 156 at the bottom of the stamping element 144 contacts the sealing element 138 and continues to be pushed downward through or pierce the sealing element 138, thereby exposing the internal volume of the sample tray 130 to the external environment.

[0067] FIG. 11A to FIG. 11D Another example of a device 170 for piercing the sealing element 138 of the sample tray 130 is shown. FIG. 11A This is a perspective view of the device 170 without any sample trays. FIG. 11B It is a perspective view of a device 170 having an airtight sample tray 130 inserted in the appropriate position. FIG. 11C This is a bottom perspective view of the device 170 and the sample tray 130, and FIG. 11D This is a perspective view of the device 170 and sample tray 130 after activation to puncture the sealing element 138.

[0068] The device 170 includes a sample tray holder configured to hold a sample tray 130 in place relative to an actuator element and a stamping element 174. In the illustrated embodiment, the actuator element is a helical coil 172 made of shape memory metal. FIG. 11A to FIG. 11C In the first state, the helical coil 172 is shaped into a conical helical coil. FIG. 11D In this configuration, the helical coil 172 is in a second state, in which it has a flattened helical shape. As used herein, a conical helical coil refers to a coil whose outer edge is nominally tangent to a truncated cone shape, and a flattened helical coil refers to a coil that is substantially planar from its inner end 180 to its outer end 182. The shape change of the helical coil 172 from the first state to the second state occurs when the temperature of the helical coil 172 changes to reach the transition temperature.

[0069] The sample tray holder includes a base 176 and a handle 178. The base 176 has an opening to allow the cylindrical sidewall 134 of the sample tray 130 to pass through when the flange 136 is positioned against the top surface of the base 176. In one example, the base 176 and handle 178 are made of sheet metal. The lower portion of the helical coil 172 is secured in place relative to the base 176 and handle 178 by passing between a pair of tabs 184 extending from the base 176 or handle 178.

[0070] The stamping element 174 includes an upper portion 188 and a lower portion having two sections 186 that flare outward at the bottom. The upper portion 188 is attached to the inner end 180 of the helical coil 172. In one example, the upper portion 188 may pass through a slot in the inner end 180 and flare outward, extending above the helical coil 172 to secure the two parts together, but other attachment methods (e.g., laser welding, epoxy bonding) may be used. Thus, as the shape of the helical spring 172 changes from the first state to the second state, the stamping element 174 moves downward toward the base 176.

[0071] By sliding the sealed sample disk 130 between two forks 190 extending from the base 176, the disk 130 is secured in a stable position within the device 170. For example... FIG. 11C As shown, a pair of curved fingers 192 (only one visible) formed in the base 176, just inside the fork 190, flex outward to receive the cylindrical sidewall 134 and relax inward to maintain contact with the sample disk 130 when fully inserted. The flange 136 of the sample disk 130 abuts against the base 176 and the top surface of the fork 190.

[0072] The apparatus 170, with a sealed sample tray 130, can be mounted in a thermal analysis instrument for sample measurement. As the internal temperature of the thermal analysis instrument rises to reach the transformation temperature of the shape memory metal, the spiral coil 172 changes from its first state shape to its second state shape, such as... FIG. 11D As shown. During this shape change, the stamping element 174 is forced downward. The opening section 186 at the bottom of the stamping element 174 contacts the sealing element 138 and continues to be pushed downward through or pierce the sealing element 138. Thus, the opening formed in the sealing element 138 exposes the internal volume of the sample tray 130 to the external environment.

[0073] FIG. 12 This is a flowchart illustrating an example of a method 300 for preparing a sample for use in a thermal analysis instrument. Method 300 can be used, for example, as referenced in the description below. FIG. 10A to FIG. 11D The sample tray 130 and the device 140 or 170 are used to perform the operation.

[0074] Method 300 includes loading (310) a sample from an inert chamber (such as a glove box) into the internal volume of a sample tray. The sample tray 130 is then hermetically sealed (320) with a sealing element 138 (such as a foil seal). The sealed sample tray 130 is secured (330) within a sample tray holder of apparatus 140, 170, which is operated to open the sample tray 130. Installation of the sample tray 130 into apparatus 140, 170 can be performed in the inert chamber or at another convenient location, as the sample is now protected from the surrounding environment. Apparatus 140, 170 is then installed (340) inside a thermal analysis instrument.

[0075] Before operating the thermal analysis instrument to obtain sample measurement data, the internal environment of the instrument (e.g., a furnace environment) is purged (350) with a user-selected gas to achieve the desired environment for subsequent sample exposure. Subsequently, the instrument temperature is changed (360) (e.g., increased) to cause a change in the shape of the device actuator elements 142, 172, which in turn moves the stamping elements 144, 174, thereby achieving puncture of the sealing element 138. The sample is thus exposed to the internal environment of the instrument, which can now be operated (370) to obtain measurement data. For example, the instrument temperature can be changed to an initial temperature, and then the temperature can be increased over time while measurement data is acquired.

[0076] It should be recognized that, without departing from the principles described herein, the apparatus for opening the sample tray according to method 300 may differ from the apparatuses 140 and 170 described above. For example, other forms of actuator elements may be used, which change shape when their temperature reaches the transition temperature. Similarly, the stamping element may differ from those described above in terms of structural configuration and how the stamping element is coupled to the actuator element. In another example, the apparatus for opening the sample tray is located inside the sample tray. In this configuration, the apparatus includes a stamping element and an actuator element, both located inside the sample tray and sealed together with the sample by a sealing element. When the transition temperature is reached, the actuator element changes shape to push the stamping element upward, thereby pushing it through or piercing the sealing element.

[0077] In the examples above, an increase in temperature is typically used to open the sample tray; however, it will be understood that in alternative embodiments, a decrease in temperature can be used to open the sample tray. In such embodiments, the shape change of the sealing element of the sample tray caused by the decreased temperature is used to remove obstructions to the gas path between the internal volume of the sample tray and the external environment. Alternatively, for the device used to open the sample tray, the shape change of the actuator element caused by the decreased temperature can allow the sealing element to be punctured. For example, the sealing element or actuator element can be an element made of shape memory metal having a transition temperature below that of the ambient environment, allowing cooling to be used to open the sample tray. An example of an instrument that can benefit from such a sealing element or actuator element is an adsorption analyzer, in which the sample can be cooled to below ambient temperature.

[0078] While numerous examples have been shown and described, this description is intended to be exemplary and not restrictive, and those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of the invention as set forth in the appended claims.

Claims

1. A sample tray for a thermal analysis instrument, the sample tray comprising: A disk having an internal volume and a gas path, the internal volume for receiving a sample, and the gas path extending from the internal volume to the outer surface of the disk; A sealing element disposed in the gas path to block the gas path, thereby sealing and isolating the internal volume from the external environment, the sealing element comprising a thermosensitive material that changes shape in response to a change in temperature of the external environment to a transition temperature, wherein the change in shape exposes the internal volume to the external environment through the gas path.

2. The sample tray according to claim 1, wherein the sealing element comprises a plug made of shape memory material.

3. The sample tray according to claim 1, wherein the sealing element is disposed on the outer surface of the tray body at the end of the gas path.

4. The sample tray according to claim 3, wherein the sealing element is a sealing ring disposed between the inner surfaces of the tray body.

5. The sample tray according to claim 3, wherein the tray body has a circumferential wall having a channel therein, and wherein the sealing element is a sealing ring disposed on the outer surface of the circumferential wall.

6. The sample tray of claim 1, wherein the sealing element comprises a plug made of a material having a melting temperature at the transition temperature.

7. The sample tray according to claim 1, wherein the sealing element comprises a metal plug having a surface on which a fusible layer is formed.

8. The sample tray according to claim 1, wherein the sealing element comprises: A stopper, wherein the stopper is disposed in the gas path; and An actuator element, coupled to the plug and made of shape memory material, having a shape that changes in response to a change in temperature from the external environment to a transition temperature, wherein the change in shape of the actuator element removes the plug from the gas path.

9. The sample tray of claim 8, wherein the actuator element is a spring made of shape memory metal.

10. The sample tray of claim 1, wherein the sample tray holds the sample during measurement by a thermal analysis instrument, and the transition temperature is below the lowest temperature in the measurement temperature range.

11. A method for preparing a sample for use in a thermal analysis instrument, the method comprising: The sample is loaded into the internal volume of a sample tray, the sample tray having a gas path that extends from the internal volume through the sample tray to the external environment; The sample is sealed in the sample tray by a sealing element that blocks the gas path from the internal volume to the external environment. The sealing element contains a thermosensitive material that changes shape in response to a change in temperature from the external environment to a transition temperature. The sample tray is loaded into the thermal analysis instrument; as well as The thermal analysis instrument is operated to change the temperature of the external environment of the sample disk to at least the transition temperature, wherein the change in shape removes the obstruction from the gas path, thereby making the internal volume in communication with the external environment.

12. The method of claim 11, wherein the external environment is confined within the thermal analysis instrument, the method further comprising purging the external environment with a user-selected gas after loading the sample tray into the thermal analysis instrument and before operating the thermal analysis instrument to change the temperature of the external environment.

13. The method of claim 11, wherein operating the thermal analysis instrument comprises: Increase the temperature of the external environment of the sample tray.

14. The method of claim 11, wherein operating the thermal analysis instrument comprises: Lower the temperature of the external environment of the sample tray.

15. The method according to claim 11, further comprising: The thermal analysis instrument is operated to change the temperature within a measurement temperature range excluding the transition temperature.

16. An apparatus for opening a sample tray for a thermal analysis instrument, the apparatus comprising: A sample tray holder, the sample tray holder being configured to fix a sample tray in a fixed position relative to the sample tray holder; An actuator element, which is fixed to the sample tray holder and is formed of a thermosensitive material, the thermosensitive material changing the shape of the actuator element in response to a change in external temperature to a transition temperature; and A stamping element is attached to the actuator element and positioned relative to the sample tray, such that a change in the shape of the actuator element in response to a change in the external temperature causes the stamping element to move to pierce the sealing element, thereby exposing the internal volume of the sample tray to the external environment.

17. The device of claim 16, wherein the actuator element is a helical spring made of shape memory metal.

18. The apparatus of claim 17, wherein the change in shape of the actuator element is a change in the length of the helical spring.

19. The device of claim 16, wherein the actuator element is a helical coil made of shape memory metal.

20. The apparatus of claim 19, wherein the change in shape of the actuator element is a change from a non-planar configuration to a planar configuration of the helical coil.

21. A method for preparing a sample for use in a thermal analysis instrument, the method comprising: The sample tray is secured in a device for opening the sample tray, the device comprising: A sample tray holder, the sample tray holder being configured to fix a sample tray in a fixed position relative to the sample tray holder; An actuator element, which is fixed to the sample tray holder and is formed of a thermosensitive material, the thermosensitive material changing the shape of the actuator element in response to a change in external temperature to a transition temperature; and A stamping element is attached to the actuator element and positioned relative to the sample tray, such that a change in the shape of the actuator element in response to a change in the external temperature causes the stamping element to move to pierce a sealing element on the sample tray, thereby exposing the internal volume of the sample tray to the external environment. The device is then mounted onto a thermal analysis instrument; The temperature of the thermal analysis instrument is changed to a transition temperature to alter the shape of the actuator element, wherein the stamping element moves to puncture the sealing element.

22. The method of claim 21, wherein the actuator element is a helical spring, and wherein the change in the shape of the actuator element is a change in the length of the helical spring.

23. The method of claim 21, wherein the actuator element is a helical coil, and the change in shape of the actuator element is a change from a non-planar configuration to a planar configuration of the helical coil.

Images