Calorimeter

Abstract

A calorimeter housing comprises a wall having a first side defining a chamber, a second side, and a passageway extending through the wall from the first to the second side. A spacer formed of thermall

Description

FIELD [0001 ] The present disclosure relates to calorimeters, in particular the installation of thermocouples within calorimeters. BACKGROUND

[0002] Accelerating rate calorimetry is used to investigate the effect of heat on materials, and is particularly applicable for simulating runaway reactions. In runaway reactions, such those that can occur when testing batteries, the calorimeter can reach significant temperatures. For example, 1000s of degrees Celsius can be reached when an explosion occurs, and elevated temperatures also occur during periodic thermal cleaning. Heaters and heat monitoring elements pass into the central chamber of the calorimeter to respectively heat and monitor said chamber. Incorrect installation of these components can cause the thermal performance of the calorimeter to deviate.

[0003] One example of a heat monitoring element is a thermocouple. Thermocouples are conventionally anchored in place, for example by clamping. Other conventional mounting options include the drilling of a thermal well through the wall of the calorimeter, with this well tightly toleraneed to the geometry of the thermocouple. Thermally conductive materials, such as thermal paste, are conventionally used when installing thermocouples with these mounting options. Whilst these materials have excellent heat transfer performance, they are prone to degradation at the high temperatures experienced in accelerating rate calorimeters. Summary

[0004] According to the present disclosure there is provided a method of installing a thermocouple in a calorimeter, and a calorimeter, as described in the accompanying claims.

[0005] According to the present disclosure there is provided a method of installing a thermocouple in a calorimeter. The method may comprise providing a calorimeter housing. The calorimeter housing may comprise a chamber wall having a first inner side defining a chamber and a second outer side. A passageway may extend through the chamber wall from the first side to the second side, the passageway having an inner surface. A thermocouple may comprise a distal tip, and a spacer dimensioned to be received within the passageway of the chamber. The spacer may be formed of thermally insulating material and may comprises a through hole passing along its axial length. The through hole may be dimensioned to receive the thermocouple therethrough. The spacer may be positioned within the passageway of the chamber, and the thermocouple may be positioned within the through hole of the spacer. The spacer may space the thermocouple away from the inner surface of the passageway of the chamber, and the distal tip of the thermocouple may be positioned flush with the first side wall of the chamber. A cement and a solvent may be mixed to form a wet paste. The cement may be provided in the form of calcined aluminium oxide and the solvent may be provided in the form of a saturated aqueous solution of sodium silicate. The wet paste may be applied around the thermocouple at the first side of the chamber wall to form a first seal between the thermocouple and the passageway of the chamber. The first seal may isolate the spacer from the chamber, a may form a thin layer over the distal tip of the thermocouple. The wet paste may also be applied around the thermocouple at the second side of the chamber wall to form a second seal between the thermocouple and the passageway of the chamber. The wet paste may then be set such that the spacer is secured within the passageway of the chamber.

[0006] In other examples, the wet paste may be applied around the thermocouple at the first side of the chamber wall to form a first seal between the thermocouple and the passageway of the chamber such that the spacer is isolated from the chamber and the distal tip of the thermocouple is covered by a thin layer of paste.

[0007] The correct installation of the thermocouples within a calorimeter housing (particularly an accelerating rate calorimeter) can be critical in ensuring that the high sensitivity and dynamic response specifications are met. Correct insertion of thermocouples may ensure minimum deviation of the manufactured calorimeter from its real-time nodal thermal model, which can form part of the calorimeter’s control algorithm. The paste composition described in this method can provide a stable and reproducible means for fitting thermocouples to a calorimeter.

[0008] By following this method, the thermal capacity and thermal conductivity associated with the thermocouple thermal bridge to the calorimeter can be consistent. The adhesive and elastic properties of the set paste can be less prone to the effects of differential expansion between the calorimeter, the paste and the thermocouple within the operating range of -50°C and 630°C.

[0009] Compared to thermal paste, the set paste of the present disclosure (which may be referred to as thermal cement) can have poorer thermal transfer but can result in the calorimeter that performs more consistently over its lifespan, due to improved securement of the thermocouple. The set paste can have improved thermal stability and does not degrade at the higher temperatures which occur in the accelerating rate calorimeter. The set paste can importantly remain stable overtime even when high temperature cleaning occurs.

[0010] The use of a spacer acts can act in synergy with the use of the wet paste of the present disclosure. The spacer can prevent ingress of the wet paste into the borehole such that set paste can be readily broken with blunt force, to allow for easy extraction of the thermocouple. [0011 ] Optionally, the thin layer of paste has a thickness of 0.2 to 0.3 mm.

[0012] Optionally, the ratio of cement to solvent by weight is in a range of at least 3:7. At least 3:7 refers to a ratio of 3:7 or higher, for example 1:2.

[0013] Optionally, setting the paste comprises allowing the wet paste to dry for a predetermined period of time to form a dry paste, whilst leaving the thermocouple, wet paste, spacer and chamber wall undisturbed. The predetermined period of time may be at least 10 hours. This can ensure the paste is fully set and thus not damaged by movement of the other components of the calorimeter. Thus, the seal may be optimally formed.

[0014] Optionally, the forming the wet paste around the thermocouple at the first side of the chamber wall comprises filling the passageway to a depth of 2.5 to 4 mm from the first side of the chamber wall. Filling the passageway to this depth can be considered the optimal depth, in that that the cement can be easily broken, allowing the thermocouple / spacerto be quickly removed and replaced.

[0015] Optionally, the forming of the wet paste around the thermocouple at the second side of the chamber wall comprises filling the passageway to a depth of 4 to 5 mm from the second side of the chamber wall. Filling the passageway to this depth can be considered the optimal depth, in that the cement can be easily broken, allowing the thermocouple / spacerto be quickly removed and replaced.

[0016] In an aspect of the present disclosure there is provided a calorimeter. The calorimeter may comprise a chamber defined by a chamber wall. The chamber wall may have a first side defining the chamber and a second outer side. A passageway may pass through the chamber wall from the first side to the second side. A spacer may be received within the passageway of the chamber. The space may be formed of thermally insulating material and may comprise a passageway passing along its axial length. A thermocouple may be positioned within the passageway of the thermally insulating spacer. The thermocouple may comprise a distal tip that is positioned flush with the first side of the chamberwallof the calorimeter. A paste may be formed from a mixture of a cement in the form of calcined aluminium oxide, and a solvent in the form of a saturated aqueous solution of sodium silicate, disposed around the thermocouple at the first side of the chamber wall to form a first seal between the thermocouple and the passageway of the chamber wall. The first seal may isolate the spacer from the chamber, whilst covering the distal tip of the thermocouple with a thin layer of paste. The paste may also be disposed around the thermocouple at the second side of the chamber wall to form a second seal between the thermocouple and the passageway of the chamber wall. The first and second seal may act to retain the spacerwithin the chamber wall. BRIEF DESCRIPTION OF DRAWINGS

[0017] The present disclosure will now be described by way of example only with reference to the following illustrative figures in which: Figure 1 shows an example of an exterior of a calorimeter body; Figure 2 shows an example of an interior of a calorimeter body; Figure 3 shows an example of a side view of a calorimeter lid; Figure 4 shows an example of a bottom view of a calorimeter lid; Figure 5 shows an example of a thermocouple positioned within a ceramic tube; Figure 6 shows an example of a thermocouple received within a passageway; Figure 7 shows an example of a thermocouple and ceramic tube received within a passageway; Figure 8 shows an example of cement for formation of a paste; Figure 9 shows an example of cement and solvent for formation of a paste; and Figure 10 shows an example of a paste formed from cement and solvent. DETAILED DESCRIPTION

[0018] The following description presents exemplary embodiments and, together with the drawings, serves to explain principles of the disclosure. The scope of the disclosure is not intended to be limited to the precise details of the embodiments or exact adherence with all method steps. Variations will be apparent to a skilled person and are deemed also to be covered by the description. Terms for features used herein should be given a broad interpretation that also encompasses equivalent functions and features. In some cases, several alternative terms (synonyms) for structural features have been provided but such terms are not intended to be exhaustive.

[0019] Descriptive terms should also be given the broadest possible interpretation; e.g. the term "comprising" as used in this specification means "consisting at least in part of" such that interpreting each statement in this specification that includes the term "comprising", features other than that orthose prefaced by the term may also be present. Related terms such as "comprise" and "comprises" are to be interpreted in the same manner. Directional terms such as “vertical”, “horizontal”, “up”, “down”, “upper” and “lower” are relative terms that may be used for convenience of explanation usually with reference to the illustrations and are not intended to be ultimately limiting if an equivalent function can be achieved with an alternative dimension and / or direction.

[0020] The description herein refers to embodiments with particular combinations of configuration steps or features. However, it is envisaged that further combinations and crosscombinations of compatible steps or features between embodiments will be possible. The description of multiple features in relation to any specific embodiment is not an indication that such features are inextricably linked, and isolated features may function independently from other features and not necessarily require implementation as a complete combination. [0021 ] The use of a paste in accordance with the present disclosure is illustrated in Figures 1 -11. An ARC calorimeter is used as an example, however the paste may be used in the other calorimeter configurations.

[0022] In some examples, accelerating rate calorimeters include a primary containment unit around which secondary shielding is provided. The primary containment unit is formed as a cylindrical body, where a chamber extends into the cylindrical body from an open end. A lid is received upon the open end of the body and acts to seal the chamber. Thus, the lid and cylindrical body together form a chamber wall. A plurality of boreholes pass from the exteriorof the primary containment unit, through the chamber wall, and into the chamber. These boreholes are dimensioned to allow thermal instrumentation, such as thermocouples, to pass through the chamber wall and into the chamber.

[0023] Figure 1 shows an example in which the body 2 of a calorimeter, where two body boreholes 4 enter the exterior surface 6 of the body 2. Figure 2 shows an example in which the chambers of the body 2 and the respective exit locations of the body boreholes 4 of Figure 1 at an inner surface 10. Figure 3 shows an example in which a side view of a lid 12 of a calorimeter where a lid borehole 14 enters the lid 12. Figure 4 shows an example in which the underside 16 of the lid 12, which also serves to define the chamber 8, where the respective exit location of the lid borehole 14 of Figure 3 exit from the underside of the lid 12. The body boreholes 4, and lid borehole 14, are each dimensioned to respectively receive a thermocouple.

[0024] In an example, thermocouple fixturing involves: 1) installing a thermocouple 18 within a spacer in the form of a ceramic tube 20 (as shown in Figure 5); 2) installing the thermocouple 18 received within the ceramic tube 20 into a respective borehole 4,14 (Figures 6 - 7); 3) applying a wet paste, formed by mixing calcined aluminium oxide and a saturated aqueous solution of sodium silicate, to the inner surface and to the exterior surface 6 of the body 2, to form a respective first seal 22 and second seal 24 between the thermocouple 18 and the chamber 8 (Figure 8); 4) setting the paste.

[0025] In the present example the thermocouple 18 comprises an elongate, substantially cylindrical body. The ceramic tube 20 includes a passageway 26 passing along its axial length. When received over the thermocouple 18 the ceramic tube 20 encircles at least a portion of the cylindrical thermocouple 18. Thus, the ceramic tube 20 may be termed a ceramic sleeve. The ceramic tube 20 is configured such that when the thermocouple 18 / ceramic tube 20 assembly is received within the borehole 4,14, the thermocouple 18 is held central to the borehole 4,14. Thus, the thermocouple 18 does not directly contact the inner surface of the borehole 4,14.

[0026] The installation of the thermocouple 18 / ceramic tube 20 assembly within the borehole 4,14 may involve positioning the ceramic tube 20 such that it is received within the borehole 4, 14 of the wall (i.e. it does not extend from the wall). As shown in Figure 6, the ceramic tube 20 does not extend from the wall, whilst the data cable for the thermocouple 18 does extends backwardlyfrom the wall. As shown in Figure 7, the ceramic tube 20 does notextend from the wall, and the thermocouple 18 is positioned such that its distal end 30 is flush with the inner surface of the wall.

[0027] In one example the step of applying the wet paste to the inner wall involves filling the borehole 4,14 to a depth of between 2.5mm and 4mm. In one example the step of applyingwet paste to the outer wall involves filling the borehole 4,14 to a depth of between 4mm and 5mm. The step of setting the paste involves removing any excess wet paste from the entry and exit locations of a borehole 4,14 (as shown in Figure 8) and allowing the wet paste to dry completely. Whilst the setting period varies depending on the composition of the wet paste, a drying period of ten hours should allow for most compositions to dry fully. This setting procedure is performed without disturbing the thermocouple 18 and body 2 / lid 12, to ensure the wet paste is not damaged by movement during setting. The set paste anchors the thermocouple 18 at the entry and exit ends of the borehole 4,14.

[0028] Due to the set paste only anchoring the thermocouple 18 at the entry and exit locations the thermocouple 18 can be quickly replaced. The use of a mixture of calcined aluminium oxide and saturated aqueous solution of sodium silicate to form a wet paste results in an optimal set paste. Thus, the set paste performs optimally during normal operation of the accelerating rate calorimeter, but it also relatively brittle. Thus, when a thermocouple 18 needs to be replaced (e.g. due to failure) the set paste can be readily broken by blunt force. This allows the thermocouple 18 and ceramic tube 20 to be removed, with any residual set paste quickly removed. Therefore, the thermocouple 18 can be quickly replaced without the need to extensively clean and prepare the boreholes 4,14.

[0029] Prior to the steps of applying and setting the paste, the wet paste is prepared (Figures 9 -11). In one example the steps of preparing the wet paste include: 1) depositing calcined aluminium oxide (a cement 32) upon a mixing surface 34 to form a raised cone of cement 32, and opening a crater in the raised cone to define a central well 36 (Figure 9); 2) depositing a saturated aqueous solution of sodium silicate (a solvent 38) into the central well 36 in a controlled manner (e.g. by using a pipette or syringe) (Figure 10); 3) mixing the cement 32 and solvent 38 until a wet paste is formed; 4) incrementally adding more cement 32 until the correct consistency of wet paste 40 is achieved.

[0030] In one example the step of mixing the cement 32 and solvent 38 involves moving cement 32 inwards from the edges of the crater into the central well 36. Use of a mixing spatula or fine screwdriver may assist in this process. Once the solvent 38 has been absorbed by the cement 32, the resultant partial mixture can be re-formed into a cone with a central well 36; further solvent 38 can be added to the well 36; and further mixing can be performed. This re-formation and mixing occurs until a fully wetted paste 40 is formed (i.e. without residual dry cement 32). To assess whether the wetted paste 40 is at the desired consistency, the mixing surface 34 may be rotated into a vertical position. When the wetted paste 40 no longer flows along the mixing surface 34 (when in the vertical position) the desired consistency is reached. If the wetted paste 40 flows along the mixing surface 34, then more cement 32 is added to increase viscosity. The consistency of the wet paste 40 beneficially ensures that the thermocouple 18 remains in good contact with the calorimeter, and can operate over the normal operating range of-50°C to 630°C. Wet paste 40 of an appropriate consistency is formed with ratios by weight of cement 32 to solvent 38 of at least 3:7.

Claims

26Claims1. A method of installing a thermocouple in a calorimeter housing, the method comprising, providing a calorimeter housing comprising a chamber wall having a first inner side defining a chamber and a second outer side, and a passageway extending through the chamber wall from the first side to the second side, the passageway having an inner surface;providing thermocouple comprising distal tip, and a spacer dimensioned to be received within the passageway of the chamber, the spacer formed of thermally insulating material and comprising a through hole passing along the axial length of the spacer, the through hole dimensioned to receive the thermocouple therethrough;positioning the spacerwithin the passageway of the chamber, and positioning the thermocouple within the through hole of the spacer such that: the spacer spaces the thermocouple away from the inner surface of the passageway of the chamber, and the distal tip of the thermocouple is positioned flush with the first inner side of the chamber wall;mixing a cement and a solvent to form a wet paste, wherein the cement is provided in the form of calcined aluminium oxide and the solvent is provided in the form of a saturated aqueous solution of sodium silicate;applying the wet paste around the thermocouple at the first side of the chamber wall to form a first seal between the thermocouple and the passageway of the chamber such that the spacer and distal tip are isolated from the chamber and the distal tip of the thermocouple is covered by a thin layer of paste;applying the wet paste around the thermocouple at the second side of the chamber wall to form a second seal between the thermocouple and the passageway of the chamber; andsetting the paste such that the spacer is secured within the passageway of the chamber.

2. A method according to claim 1, wherein the thin layer of paste has a thickness of 0.2 to 0.3 mm.

3. A method according to claim 1, wherein the ratio of cement to solvent by weight is at least 3:7.

4. A method according to any preceding claim, wherein setting the paste comprises allowing the wet paste to dry for a predetermined period of time to form a dry paste, whilst leaving the thermocouple, wet paste, spacer and chamber wall undisturbed.

5. A method according to any preceding claim, wherein the forming the wet paste around the thermocouple at the first side of the chamber wall comprises filling the passageway to a depth of 2.5 to 4 mm from the first side of the chamber wall.

6. A method according to any preceding claim, wherein the forming of the wet paste around the thermocouple at the second side of the chamber wall comprises filling the passageway to a depth of 4 to 5 mm from the second side of the chamber wall.23 01 26IntellectualPropertyOfficeApplication GB2507760.3Search report under Section 17 of the Patents Act 1977Date search completed: 19 November 2025Claims searched: 1-7International classificationSubclass and subgroup Valid from G01K1 / 08 01 / 01 / 2021 G01K1 / 14 01 / 01 / 2021 G01K1 / 16 01 / 01 / 2006 G01K17 / 02 01 / 01 / 2006 G01K17 / 04 01 / 01 / 2006 G01K7 / 04 01 / 01 / 2006Field of searchWorldwide search of patent documents classified in the following areas of the IPC:G01KDatabases used in the preparation of this search report:SEARCH-PATENTIntellectual Property Office is an operating name of the Patent OfficeWWW.goV.Uk / ipoDocuments considered to be relevantPatent literatureCategory Relevant claims Document of relevance A - FR 2181933 A1 (ELECTRO NITE), See refractory cement comprising alumina and silicate of soda. A - JP 6981028 B2 (SUMITOMO OSAKA CEMENT CO LTD), See refractory material 24, fig.

5. A - CN 114150200 B (BEIJING FIRST STEEL STOCK LTD COMPANY), See figs and para 80. A - CN 119738054 A (CLP HUACHUANG SUZHOU POWER TECH RESEARCH CO LTD), See paras 16-21. A - US 9895557 B2 (SEUNTJENS et al.), See fig. 3B. Non-patent literature Category Relevant claims Document of relevanceCategoriesLetter or DescriptionsymbolLetter or symbol Description X Document indicating lack of novelty or inventive step.Y Document indicating lack of inventive step, if combined with another document of the same category. & Member of the same patent family. A Document indicating technological background. P Document published on or after the priority date but before the fling date of the present application. E Earlier application published on or after the filing date of the present application.

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