GB2614520A

GB2614520A - Analytical apparatus

Info

Publication number: GB2614520A
Application number: GB2114919.0A
Authority: GB
Inventors: Philip Mylrea Ian
Original assignee: STANHOPE SETA Ltd
Current assignee: STANHOPE SETA Ltd
Priority date: 2021-10-19
Filing date: 2021-10-19
Publication date: 2023-07-12
Also published as: GB202114919D0

Abstract

An analytical apparatus comprising includes a first assembly 110, a second assembly 112, a heat sink 126, a first Peltier device (fig 3; 122) located between the first assembly and the heat sink, and a second Peltier device (fig 3; 124) located between the second assembly and the heat sink, wherein the first Peltier device is configured to transfer heat 134 from the first assembly to the heat sink to reduce and/or maintain the temperature of the first assembly below ambient temperature, and the second Peltier device is configured to convey heat 134 from the heat sink to the second assembly to increase and/or maintain the temperature of the second assembly above ambient temperature. A method of operating an analytical apparatus comprises transferring heat from a first assembly to a heat sink using a first Peltier device reduce and/or maintain the temperature of a first assembly and conveying the heat from the heat sink to a second assembly using a second Peltier device to increase and/or maintain the temperature of the second assembly. Ideally, the apparatus detects hydrogen sulfide (H2S) in liquid petroleum fuel products. In use, the second assembly heats a test vessel containing the sample and the first assembly comprises a filter for removing contaminants from liberated sample before detection.

Description

Analytical Apparatus The present invention relates to an analytical apparatus and an associated method of operating an analytical apparatus. More particularly, the present invention relates to an analytical apparatus configured to be more energy efficient, compact, and easily operated.

The analytical apparatus may also require fewer parts to manufacture than conventional analytical apparatus of an equivalent type.

Often, in order for an analytical apparatus to perform an analysis of a composition, it is necessary to cool one component of the apparatus and heat another. This is the case when the analytical apparatus employs, for example, vapour phase processing. Where an analytical apparatus employs vapour phase processing, it is sometimes necessary to heat a test vessel containing a sample to a temperature above ambient temperature, cool a filter cartridge to a temperature below ambient temperature, and maintain the respective temperatures of the test vessel and filter cartridge whilst an analysis of the sample takes place. The elevated temperature of the test vessel causes the sample to experience a phase change from liquid to gas. The gas is then passed through the filter cartridge in order to remove any contaminants before one or more constituents of the composition are measured by an electrochemical sensor. The composition of the sample can be determined in this manner.

Conventionally, the component of the apparatus to be heated (e.g. an assembly containing the test vessel) and the component of the apparatus to be cooled (e.g. an assembly containing the filter cartridge) are contained in separate housings and are heated or cooled independently. In one example, a heat pump may heat the component of the apparatus requiring heating while a separate, independently-powered, heat pump cools the component of the apparatus requiring cooling. The heat pump performing the cooling may then dissipate the surplus heat energy to a heatsink. This surplus energy is not always harnessed and therefore the energy may be wasted. Wasted energy reduces the energy efficiency of the apparatus. Housing the components separately also increases the spatial footprint of the apparatus and reduces its portability. Although analytical apparatus are often used in a laboratory, they can also be used in the field or as part of an online process wherein samples are diverted from one or more process streams into the apparatus to provide real-time, or close to real-time, analysis of the properties of the samples. For these latter modes of operation, the size and portability of the apparatus often have a greater bearing on the apparatus' suitability for use. Size may also impact the user experience of an operator. The number of parts used to retain components in separate housings is also increased. An apparatus with a greater number of parts will usually be associated with an increased manufacturing burden as more parts generally result in, for example, a more complex and costly assembly process. The present invention seeks to reduce or mitigate one or more of the disadvantages posed by conventional analytical apparatus.

According to a first aspect of the invention there is provided an analytical apparatus. The analytical apparatus comprises a first assembly; a second assembly; a heat sink; a first Peltier device located between the first assembly and heat sink; and a second Peltier device located between the second assembly and the heat sink, wherein the first Peltier device is configured to transfer heat from the first assembly to the heatsink to reduce and/or maintain the temperature of the first assembly below ambient temperature, and the second Peltier device is configured to convey heat from the heat sink to the second assembly to increase and/or maintain the temperature of the second assembly above ambient temperature. Arranging the first and second Peltier devices such that waste heat energy generated by the first Peltier device as a result of reducing and/or maintaining the first assembly below ambient temperature is harnessed by the second Peltier device in order to increase and/or maintain the temperature of the second Peltier device above ambient temperature optimises the energy efficiency of the analytical apparatus.

The analytical apparatus may include a first temperature sensor for measuring the temperature of the first assembly. The analytical apparatus may include a second temperature sensor for measuring the temperature of the second assembly. The first Peltier device may be configured to transfer heat from the first assembly to the heat sink to reduce and subsequently maintain the temperature of the first assembly at a temperature below ambient temperature, and the second Peltier device may be configured to convey heat from the heat sink to the second assembly to increase and subsequently maintain the temperature of the second assembly at a temperature above ambient temperature. The first Peltier device may be configured to reduce the temperature of the first assembly to, and maintain the temperature of the first assembly at, a temperature between -5 °C and -30°C.

The second Peltier device may be configured to increase the temperature of the second assembly to, and maintain the temperature of the second assembly at, a temperature between 20°C to 100°C. The first Peltier device may be configured to reduce the temperature of the first assembly to, and maintain the temperature of the first assembly at, -20°C. The second Peltier device may be configured to increase the temperature of the second assembly to, and maintain the temperature of the second assembly at, 60°C. The first Peltier device and the second Peltier device may be powered simultaneously. The analytical apparatus may include a controller, said controller storing instructions which, when executed, at least partially operate the analytical apparatus. The first assembly, the second assembly and the heat sink may be contained within a common housing. The analytical apparatus may include a first thermal insulating medium, wherein the first thermal insulating medium divides the housing into a first compartment and a second compartment, the first compartment housing the first assembly and the second assembly, and the second compartment housing the heat sink, wherein the first Peltier device and the second Peltier device are embedded within the first thermal insulating medium. The analytical apparatus may include a second thermal insulating medium, wherein the second thermal insulating medium is between the first assembly and second assembly. The analytical apparatus may include a third thermal insulating medium, wherein the third thermal insulating medium is between the first and/or second assemblies and one or more outer walls of the first compartment. The second compartment may include one or more walls, and the one or more walls may include a vent. The first assembly may include a first jacket for carrying a filter cartridge. The jacket may be configured such that the first Peltier device is in indirect contact with the filter cartridge residing in the first jacket. The second assembly may include a second jacket for carrying a sample test vessel. The second jacket may be configured such that the second Peltier device is in indirect contact with the test vessel residing in the second jacket. The analytical apparatus may be a hydrogen sulphide analyser. These and other features of the analytical apparatus will now be described in additional detail.

Each of the first and second Peltier devices may have two opposing faces: a first face which is in contact with the first or second assembly, respectively, and a second face which is in contact with the heat sink. The first Peltier device is configured such that when an electric current is applied to the first Peltier device, heat energy is transferred from the first face of the first Peltier device to the second face of the first Peltier device in order to reduce and/or maintain the temperature of the first assembly below ambient temperature. The second Peltier device is configured such that when an electric current is applied to the second Peltier device, heat energy is transferred from the second face of the second Peltier device to the first face of the second Peltier device in order to increase and/or maintain the temperature of the second assembly above ambient temperature. Ambient temperature is the temperature of the immediate environment within which the analytical apparatus is situated when operating. The apparatus may function at any ambient temperature, including room temperature (e.g. 15 to 25°C). By placing the second face of the first Peltier device and the second face of the second Peltier device in contact with the heat sink, the heat energy transferred to the second face of the first Peltier device, which would otherwise be wasted, is made available to the second face of the second Peltier device via the heatsink. The availability of this heat energy reduces the current required to achieve a desired temperature at the first face of the second Peltier device. Elevating the temperature of the second face of the second Peltier device by placing it in contact with the heat sink reduces the temperature gradient required across the second Peltier device to increase the temperature of the first face when compared with the instance in which the second face of the second Peltier device is in contact with surroundings having a lower temperature, e.g. ambient temperature.

The analytical device may further include a first temperature sensor for measuring the temperature of the first assembly and/or a second temperature sensor for measuring the temperature of the second assembly. Data from the first and/or second temperature sensors may be utilised to control the temperature of the first and/or second assemblies. As the current supplied to a Peltier device is proportional to the temperature gradient across the Peltier device, i.e. the more current supplied the greater the magnitude and rate of transfer of heat energy across the Peltier device, the temperature of the first and second assemblies can be controlled by controlling the supply of power to the first and second Peltier devices in response to data provided by the first and/or second temperature sensors, respectively. For example, when the temperature of the first assembly is sensed by the first temperature sensor as being higher than desired, the power, and consequently the current, supplied to the first Peltier device may be increased, in order to transfer more energy from the first assembly to the heat sink, until the temperature of the first assembly reaches the desired temperature. Similarly, when the temperature of the first assembly is sensed by the first temperature sensor as being lower than desired, the power, and consequently the current, supplied to the first Peltier device may be reduced in order to transfer less energy from the first assembly to the heat sink, or stopped in order to stop transferring energy from the first assembly to the heat sink, until the temperature of the first assembly reaches the desired temperature. The direction of current through the first Peltier device could also be reversed when the temperature of the first assembly is sensed by the first temperature sensor as being lower than desired in order to transfer energy from the heat sink to the first assembly until the temperature of the first assembly reaches the desired temperature. The reverse process applies for regulating the temperature of the second assembly. When the temperature of the second assembly is sensed by the second temperature sensor as being higher than desired, the power, and consequently the current, supplied to the second Peltier device may be reduced, in order to transfer less energy from the heat sink to the second assembly, or stopped in order to stop transferring energy from the heat sink to the second assembly, until the temperature of the second assembly reaches the desired temperature.

The direction of current through the second Peltier device could also be reversed when the temperature of the second assembly is sensed by the second temperature sensor as being higher than desired, in order to transfer energy from the second assembly to the heat sink until the temperature of the second assembly reaches the desired temperature. When the temperature of the second assembly is sensed by the second temperature sensor as being lower than desired, the power, and consequently the current, supplied to the second Peltier device may be increased, in order to transfer more energy from the heat sink to the second assembly, until the temperature of the second assembly reaches the desired temperature. A feedback control loop may be implemented for this purpose. Such a feedback loop may be processed continuously when preparing to analyse, and/or during the analysis of, a sample in order to minimise undesirable temperature fluctuations of the first and second assemblies.

The first and second Peltier devices may be configured to: reduce the temperature of the first assembly and increase the temperature of the second assembly; reduce the temperature of the first assembly and maintain the temperature of the second assembly; maintain the temperature of the first assembly and increase the temperature of the second assembly; and/or maintain the temperature of the first and second assemblies. Furthermore, the first Peltier device may be configured to transfer heat from the first assembly to the heat sink to reduce and subsequently maintain the temperature of the first assembly at a temperature below ambient temperature, and the second Peltier device may be configured to convey heat from the heat sink to the second assembly to increase and subsequently maintain the temperature of the second assembly at a temperature above ambient temperature. Such a configuration is particularly advantageous as it is often necessary to alter the temperature of the first and second assemblies in preparation for an analysis, and then maintain that temperature for a period of time sufficient for the analysis to take place.

The first Peltier device may be configured to reduce the temperature of the first assembly to, and maintain the temperature of the first assembly within, a particular temperature range. The first Peltier device may be configured to maintain the first assembly at a temperature of from 10°C to -30°C, 5°C to -30°C, 0°C to -30°C, -5°C to -30°C, -10°C to -30°C, 10°C to -25°C, 5°C to -25°C, 0°C to -25°C, -5°C to -25°C, -10°C to -25°C, 10°C to -20°C, 5°C to -20°C, 0°C to -20°C, -5°C to -20°C, -10°C to -20°C, 10°C to -15°C, 5°C to -15°C, 0°C to -15°C, -5°C to - 15°C, -10°C to -15°C, or any other suitable temperature range. In one particular example, the first Peltier device may maintain the temperature of the first assembly at or between -5°C and -30°C. It may be advantageous for the first Peltier device to maintain the temperature of the first assembly at -20°C. The second Peltier device may be configured to increase the temperature of the second assembly to, and maintain the temperature of the second assembly within, a particular temperature range. The second Peltier device may be configured to maintain the second assembly at a temperatures of from 10°C to 70°C, 15°C to 70°C, 20°C to 70°C, 25°C to 70°C, 30°C to 70°C, 10°C to 65°C, 15°C to 65°C, 20°C to 65°C, 25°C to 65°C, 30°C to 65°C, 10°C to 60°C, 15°C to 60°C, 20°C to 60°C, 25°C to 60°C, 30°C to 60°C, 10°C to 55°C, 15°C to 55°C, 20°C to 55°C, 25°C to 55°C, 30°C to 55°C, 10°C to 50°C, 15°C to 50°C, 20°C to 50°C, 25°C to 50°C, 30°C to 50°C, or any other suitable temperature range. In one example, the second Peltier device may maintain the temperature of the second assembly at or between 20°C to 100°C. It may be advantageous for the second Peltier device to maintain the temperature of the second assembly at 60°C, for example, for testing marine or crude oils. It may be advantageous for the second Pe!ter device to maintain the temperature of the second assembly at 20°C, for example, for proficiency testing. The sample used for proficiency testing is typically a water-based solution which, when heated to a higher temperature such as the 60°C used for testing marine or crude oils, produces an undesirably high quantity of condensation throughout the apparatus. Maintaining the temperature of the second assembly at 20°C mitigates this problem. For this reason, it may also be advantageous to maintain the temperature of the second assembly at 20°C when testing crude oil distillates. A specific temperature, or temperature range, is particularly advantageous when, for example, the temperatures or temperature ranges coincide with the temperatures at which one or more characteristics of a sample are optimally detected via the analytical apparatus. For example, the temperature ranges may be suitable where the analytical apparatus is used to detect levels of hydrogen sulphide present in a sample. The first Peltier device may be configured to maintain the temperature of the first assembly at a temperature with an accuracy of ±2°C. For example, in the example described above, -20°C±2°C. The second Peltier device may be configured to maintain the temperature of the second assembly at a temperature with an accuracy of ±1°C. For example, in the examples described above, 60°C±1°C or 20t±1 C. The first and second Peltier devices may be powered consecutively. More particularly, the first Peltier device may be powered first followed by the second Peltier device once the first Peltier device is no longer being powered. In this configuration the second Peltier device utilises heat energy which remains in the heat sink once the first Peltier device is no longer being powered. Alternatively, the first and second Peltier devices may be powered simultaneously. Simultaneous powering may be entirely simultaneous. The first and second Peltier devices are powered entirely simultaneously when both Peltier devices are powered at the same time for the same length of time. Alternatively, simultaneous powering may be partly simultaneous. The first and second Peltier devices are powered partly simultaneously when the second Peltier device is powered after the first Peltier device but whilst the first Peltier device is still being powered. Powering the first and second Peltier devices simultaneously optimises the availability of the heat energy produced by the first Peltier device at the second Peltier device, thereby optimising the energy efficiency of the analytical apparatus. Alternatively, the second Peltier device may be powered first followed by the first Peltier device, whilst the second Peltier device is being powered. This configuration may be useful where the ambient temperature is relatively low and therefore more power is required to raise the temperature of the second assembly than is required to lower the temperature of the first assembly. The first Peltier device may be powered after the second Peltier device as the second assembly is reaching the desired temperature, thereby optimising the energy efficiency of the apparatus when the ambient temperature is relatively low.

The analytical apparatus may further include a controller for operating the analytical apparatus. The controller may control one or more components of the analytical apparatus, and may additionally, or alternatively, facilitate and/or control the communication of information and/or data between one or more components of the analytical apparatus. For example, the controller may facilitate the abovementioned feedback loop, i.e. receive temperature measurements from the first and second temperature sensors and adjust the power supplied to the first and second Peltier devices in response in order to reduce, increase or maintain the temperature of the first and second assemblies at the desired temperature. Furthermore, the controller may be in communication with a device user interface, such as a graphical user interface. The user interface may enable an operator to enter the respective desired temperatures of the first assembly and the second assembly such that the controller may regulate the temperature of the first and second assemblies accordingly. Information such as the real-time temperature of the first and second assemblies, the time remaining for an analysis to be completed, and the final outcome of the analysis (e.g. the quantity of a particular constituent of the composition) may be displayed on a display screen.

The controller may be a plurality of components and may, in one example, be in the form of a computer integrated with the analytical apparatus. The controller may be a programmable logic controller (PLC) or other computing device that can carry out instructions. The controller may include one or multiple processing elements that are integrated in a single device or distributed across devices. The controller may further include a processor to manage all the components within the controller. Where present, the processor may process all data flow between the components within the controller. The processor may be any of a central processing unit, a semiconductor-based microprocessor, an application specific integrated circuit (ASIC), and/or other device suitable for retrieval and execution of instructions. The controller may further include a storage or memory unit to store any data or instructions which may need to be accessed by, for example, a processor. Where present, the memory unit may be any form of storage device capable of storing executable instructions, such as a non-transient computer readable medium, for example Random Access Memory (RAM), Electrically-Erasable Programmable Read-Only Memory (EEPROM), a storage drive, an optical disc, or the like. In an example, the controller may include a PLC (programmable-logic-controller. In another example, the controller may implement a PID (proportional-integral-derivative) controller. In a further example, the controller may implement a FO (fractional-order) controller. In yet another example, the controller may implement an 10 (integer-order) controller. The controller may include circuitry such as measurement circuitry. The controller may operate in a closed-loop or an open-loop manner dependent upon the wider functions to be carried out by the controller.

The first assembly, the second assembly and the heat sink may be contained within a common housing. The housing may have any shape, including a rectangular prism, or cross-section, including rectangle or square. In other examples, the housing may have a spherical shape or circular cross-section. In yet other examples, the housing may have an irregular shape or cross-section including linear portions and hemi-circular portions. Containing these components in a common housing may reduce the spatial footprint of the analytical apparatus when compared with conventional analytical apparatus. A reduction in the spatial footprint of the analytical apparatus may increase its portability. The first assembly, second assembly and/or heat sink may be integral to the housing or, alternatively, may be modular components which can be detached from the housing and any other components contained within the housing. The first and second compartments may be any shape, including a rectangular prism, and may have any cross-section, including rectangle or square. The first and second compartments may be the same shape or different shapes. The first and second compartments may be any suitable three-dimensional shape, including shapes substantially disclosed herein.

The analytical apparatus may further include a first thermal insulating medium. The first thermal insulating medium may divide the housing into a first compartment and a second compartment, the first compartment housing the first assembly and the second assembly, and the second compartment housing the heat sink. The first Peltier device and the second Peltier device may be embedded within the first thermal insulating medium. The first Peltier device may form a selectively conductive thermal pathway from the first assembly to the heat sink. The first Peltier device may be in direct contact with the first assembly and heat sink, or alternatively in direct contact with one or more conductive components located between, and in contact with, the first assembly or heat sink. The second Peltier device may form a selectively conductive thermal pathway from the heat sink to the second assembly.

The second Peltier device may be in direct contact with the second assembly and the heat sink, or alternatively in direct contact with one or more conductive components located between, and in contact with, the second assembly or heat sink. The first insulating medium may divide the housing in two such that the first compartment and second compartment are approximately the same size and/or volume. However, the first and second compartments may be of different size and/or volume. By installing the first thermal insulating medium between the first compartment and the second compartment, heat energy may be transferred to/from the first assembly and the second assembly substantially exclusively via the first and second Peltier devices, as opposed to, for example, via direct conduction between the first and second assemblies and the heat sink. Therefore, the first thermal insulating medium may enable a greater control over the temperature of the first and second assemblies. The heat energy transferred by the Peltier devices and/or the current passed through the Peltier devices may result in a more accurate, precise, and/or directly calculable change in temperature as heat energy is not inadvertently transferred between the first and second assemblies and the heat sink by other means. In brief, reducing the routes of thermal loss during the transfer process may increase the efficiency of heat transfer while improving the controllability of the analytical apparatus.

The analytical apparatus may further include a second thermal insulating medium, wherein the second thermal insulating medium is between the first assembly and the second assembly. The second thermal insulating medium may be formed, at least in part, from the same material as used to form the first thermal insulating medium. In a similar manner to the first thermal insulating medium, the second thermal insulating medium may function to ensure heat energy is transferred to/from the first assembly and/or second assembly substantially exclusively via the first and second Peltier devices, as opposed to, for example, via direct conduction between the first assembly and second assembly, thereby allowing greater control over the temperature of the first and second assemblies.

The analytical apparatus may include one or more walls. The one or more walls of the analytical apparatus may form at least part of the housing and/or the first compartment and/or the second compartment of the analytical apparatus. The analytical apparatus may further include a third thermal insulating medium, wherein the third thermal insulating medium is between the first and/or second assemblies and one or more, or all, outer walls of the first compartment. The third thermal insulating medium may be formed, at least in part, from the same material used to form the first and/or second thermal insulating medium. The second and/or third insulating mediums may be monolithic. In a similar manner to the first and/or second thermal insulating mediums, the third thermal insulating medium may function to ensure heat energy is transferred to/from the first assembly and the second assembly substantially exclusively via the first and second Peltier devices, as opposed to, for example, via direct conduction between the first assembly and/or the second assembly and the walls of the first compartment, thereby allowing greater control over the temperature of the first and second assemblies.

The first, second, and/or third thermal insulating mediums, where present, may reduce thermal losses from the system via conduction, convection, or other heat loss mechanisms. The first, second and/or third thermal insulating mediums may be, or include, a foam material. The foam material may be a closed-cell rubber foam, such as polychloroprene.

At least one of the one or more walls may include a vent. A vent may be present in or on one of the one or more walls of the second compartment. Additionally, or alternatively, a vent may be present in or on one of the one or more walls of the first compartment. A vent may provide a means to open the system to allow for surplus heat energy to be expelled from the heat sink in order to protect the analytical apparatus from over-heating and subsequent failure. The analytical apparatus may include a plurality of vents. Where the analytical apparatus includes a plurality of vents, a vent may be present in or on each of a first wall and a second wall of the second compartment. Any given wall may include one or more vents.

The, or each, vent may include a closure means. The closure means may allow the vent to be closed in a first configuration to limit or prevent the flow of air and subsequent loss of heat through the vent and open in a second configuration to allow the flow of air and loss of heat through the vent. Where a plurality of vents are present, each vent may include an independently actuated closure means. In an example, a closure means may include a flap, screen, or door. The closure means may be operated and/or actuated via the controller. The controller may actuate the closure means in response to a temperature reading from one or more temperature sensors, where present. A temperature sensor may be present in, on, or in proximity to the heat sink for this purpose. The apparatus may include one or more fans to aid air flow through the vents.

The first assembly may include a first receptacle suitable for carrying, or adapted to carry, a filter cartridge. The first receptacle may be a first jacket. The second assembly may include a second receptacle suitable for, or adapted for carrying, a test vessel. The second receptacle may be a second jacket. The first and second jackets may be configured to insulate the filter cartridge and/or test vessel, respectively. The first and second jackets may provide insulation in addition, or in alternative, to the second and third insulating mediums. Where the first and second jackets are insulating jackets, the first and second Peltier devices may be in direct contact with the filter cartridge and test vessel respectively, for example, through a hole in each of the first and second jackets. Alternatively, the first and second jackets may be configured to conduct heat to withdraw heat from/provide heat to the filter cartridge and/or the test vessel. Where the first and second jackets are conductive jackets, the first and second Peltier devices may be in direct contact with the first and second jackets, and thereby in indirect contact with the test vessel and filter cartridge, respectively. The conductive jackets may be made from, or include, aluminium. The test vessel may be any vessel that can contain a volume of a sample sufficient for an analysis to take place. The sample may include a diluent. Where the sample is a liquid, the test vessel may include a fluid receptacle such as a test tube, bottle, dish, trough, cup, jar or beaker. The filter cartridge may be any component capable of absorbing a fluid, including gas. The analytical apparatus may further include an air filter for filtering air which may be provided to the test vessel in order to extract the constituent to be measured from the sample. The analytical apparatus may further include one or more valves for re-directing air flow through the apparatus, for example solenoid valves. The analytical apparatus may further include a liquid trap located between the test vessel and filter cartridge in order to remove surplus liquid from the air flow before reaching the filter cartridge. The apparatus may further include one or more flow meters for measuring fluid flow through the apparatus.

The analytical apparatus may include one or more further assemblies in addition to the first and second assemblies. For example, the analytical apparatus may include a third assembly and a fourth assembly. The additional assemblies may share one, several, or all the characteristics of the first and/or second assemblies. There may be one Peltier device for each of the additional assemblies, and the Peltier devices may be configured to allow heat to be directed to/from each, or subsets, of the additional assemblies. The skilled person, with the benefit of this disclosure, will readily appreciate that the direction of the electrical current supplied to the first and second Peltier devices, and any additional Peltier devices associated with additional assemblies which may form part of the analytical apparatus, can be changed to adjust the direction of heat energy through the Peltier devices, thereby redirecting the flow of heat energy through the system. For example, the direction of current through the first Peltier device and the second Peltier device could be reversed such that heat energy flows from the second assembly to the first assembly via the heat sink, as opposed to from the first assembly to the second assembly via the heat sink. In an example, the Peltier devices of the first and third assemblies may be configured to cool the first and third assemblies, and the Peltier devices of the second and fourth assemblies may be configured to heat the second and fourth assemblies. In this example, the first and third assemblies transfer heat to the heat sink, and the second and fourth assemblies convey heat from the heat sink.

The analytical apparatus may be suitable for analysing hydrogen sulphide. The analytical device may be a hydrogen sulphide analyser. In particular the apparatus may be suitable for analysing hydrogen sulphide in liquid petroleum products including heavy residual marine fuels, distillate marine fuels, fuel oils, road transport diesel fuels, stationary power fuels, refinery feedstocks, light distillate products, crude oils, process water and the like. The apparatus may be sensitive to a measurement range of between 0-250 mg/kg hydrogen sulphide.

According to a second aspect of the invention there is provided a method of operating an analytical apparatus. The method comprises transferring heat from a first assembly to a heat sink using a first Peltier device to reduce and/or maintain the temperature of the first assembly below ambient temperature; and conveying heat from a heat sink to a second assembly using a second Peltier device to increase and/or maintain the temperature of the second assembly above ambient temperature.

The method may include transferring heat from a first assembly to a heat sink using a first Peltier device to reduce and subsequently maintain the temperature of the first assembly at a temperature below ambient temperature; and conveying heat from a heat sink to a second assembly using a second Peltier device to increase and subsequently maintain the temperature of the second assembly at a temperature above ambient temperature.

The method may further comprise placing a filter cartridge into a first jacket of the first assembly; inserting a sample test vessel into a second jacket of the second assembly; transferring heat from the first assembly to the heat sink using the first Peltier device to reduce and subsequently maintain the temperature of the first assembly at a particular temperature range; and conveying heat from the heat sink to the second assembly using the second Peltier device to increase and subsequently maintain the temperature of the first assembly at a particular temperature range. The temperature range of the first assembly may be from 10°C to -30°C, 5°C to -30°C, 0°C to -30°C, -5°C to -30°C, -10°C to -30°C, 10°C to -25°C, 5°C to -25°C, 0°C to -25°C, -5°C to -25°C, -10°C to -25°C, 10°C to -20°C, 5°C to -20°C, 0°C to -20°C, -5°C to -20°C, -10°C to -20°C, 10°C to -15°C, 5°C to -15°C, 0°C to -15°C, -5°C to -15°C, -10°C to -15°C, or any other suitable temperature range. In one particular example, the temperature range of the first assembly may be at or between -5°C and -30°C.

It may be advantageous for the first Peltier device to maintain the temperature of the first assembly at -20°C. The temperature range of the second assembly may be from 10°C to 70°C, 15°C to 70°C, 20°C to 70°C, 25°C to 70°C, 30°C to 70°C, 10°C to 65°C, 15°C to 65°C, 20°C to 65°C, 25°C to 65°C, 30°C to 65°C, 10°C to 60°C, 15°C to 60°C, 20°C to 60°C, 25°C to 60°C, 30°C to 60°C, 10°C to 55°C, 15°C to 55°C, 20°C to 55°C, 25°C to 55°C, 30°C to 55°C, 10°C to 50°C, 15°C to 50°C, 20°C to 50°C, 25°C to 50°C, 30°C to 50°C, or any other suitable temperature range. In one particular example, the temperature range of the second assembly may be at or between 20°C to 100°C. It may be advantageous for the second Peltier device to maintain the temperature of the second assembly at 20°C. It may be advantageous for the second Peltier device to maintain the temperature of the second assembly at 60°C.

These and other aspects of the invention will now be described with reference to the following drawings, in which Figure 1 shows a schematic representation of an analytical apparatus; Figure 2 shows a schematic representation of the analytical apparatus of Figure 1 with the walls of the second compartment removed to illustrate the first and second assemblies; Figure 3 shows a schematic representation of the analytical apparatus of Figure 2 with the first and second assemblies removed to illustrate the first and second Peltier devices; Figure 4 shows a schematic representation of the energy flow through the analytical apparatus of Figure 1; Figure 5 shows a flow diagram of a method of operating an analytical apparatus; and Figure 6 shows a flow diagram of a method of operating an analytical apparatus.

Figure 1 shows a schematic representation of at least a part of an analytical apparatus 100. The analytical apparatus 100 comprises a housing 102 which is divided into a first compartment 104 and a second compartment 106 by a first insulating medium 108. The housing 102 has the shape of a rectangular prism, and the first compartment 104 and the second compartment 106 also have the shape of a rectangular prism and are approximately equal in size. The first compartment 104 houses a first assembly 110 and a second assembly 112. The first assembly 110 is adapted to carry a filter cartridge and the second assembly 112 is adapted to carry a test vessel. The second compartment 106 contains a heat sink (not shown), and accordingly has a vent 114 to enable surplus heat to be expelled from the heat sink. The analytical apparatus further comprises device user interface 116 which is communicably coupled to a controller 136. An operator may input information such as the desired temperature of the first assembly 110 and/or second assembly using the user interface 116. Additionally, or alternatively, a user may input the weight of the sample in order for the controller 136 to calculate the quantity of the constituent of the sample being measured, for example hydrogen sulphide, relative to the sample quantity. The units of the outcome of this calculation may be mg/kg. Although the controller 136 is shown external to the apparatus 100, the controller may be internal, integral, and/or part of the apparatus 100.

The skilled person, with the benefit of this disclosure will understand the suitable configuration and placement of a controller for use with the apparatus 100.

Figure 2 shows a schematic representation of the analytical apparatus 100 shown in Figure 1 with the walls of the second compartment removed, and shows the first assembly 110 and second assembly 112 in greater detail. The first assembly comprises a first temperature sensor 118 and the second assembly comprises a second temperature sensor 120. A second insulating medium (not shown) may be present between the first assembly 110 and second assembly 112. Similarly, a third insulating medium (not shown) may be present between the first assembly 110 and/or second assembly 112 and at least one, or all, of the walls of the first compartment 104.

Figure 3 shows a schematic representation of the analytical apparatus 100 shown in Figure 2 with the first and second assemblies removed, and shows the first Peltier device 122 and second Peltier device 124. The first Peltier device 122 and second Peltier device 124 are embedded within the first insulating medium 108. The first Peltier device 122 is configured such that a first face of the first Peltier device 122 is in contact with the first assembly 110 and a second face (not shown) is in contact with the heat sink (not shown). Similarly, the second Peltier device 124 is configured such that a first face of the second Peltier device 124 is in contact with the second assembly 112 and a second face (not shown) is in contact with the heat sink (not shown). The first Peltier device 122 and second Peltier device 124 are controlled by the controller 136.

Figure 4 shows a schematic representation of the energy flow through the analytical apparatus 100 when the first Peltier device 122 and second Peltier device 124 are operating.

The first Peltier device 122 is configured such that electric current applied to the first Peltier device 122 transfers heat energy from the first assembly 110 to the heat sink 126. The second Peltier device 124 is configured such that electric current applied to the second Peltier device 124 transfers heat energy from the heat sink 126 to the second assembly 112. When the first Peltier device 122 and the second Peltier device 124 are in operation, heat is transferred through the apparatus as shown in indicators 134.

Figure 5 shows a flow diagram of a method 200 of operating the analytical apparatus 100. The method includes transferring 202 heat from the first assembly 110 to the heat sink 126 using the first Peltier device 122 to reduce and/or maintain the temperature of the first assembly 110 below ambient temperature. The method further includes conveying 204 heat from the heat sink 126 to the second assembly 112 using a second Peltier device 124 to increase and/or maintain the temperature of the second assembly 112 above ambient temperature.

Figure 6 shows a flow diagram of a method 300 of operating an analytical apparatus, particularly suitable for analysing the quantity of hydrogen sulphide in a sample. The method includes placing 302 a filter cartridge into a first jacket of the first assembly 110. The method further includes inserting 304 a test vessel, into a second jacket of a second assembly 112. The method further includes transferring 306 heat from the first assembly 110 to the heat sink 124 using the first Peltier device 120 to reduce and subsequently maintain the temperature of the first assembly at -20°C. The method yet further includes conveying 308 heat from the heat sink 124 to the second assembly 112 to increase and subsequently maintain the temperature of the second assembly 112 at 60°C. The steps of the method may be carried out in any suitable order. For example, the placing 302 may occur after the inserting 304. In another example, the placing 302 and the inserting 304 may be carried out after the transferring 306, the conveying 308, or both the transferring 306 and the conveying 308.

The skilled person, with the benefit of this disclosure, will appreciate that methods 200 and 300 may include one or more additional steps. For example, the method may include adding the sample to the test vessel. The method may include adding a diluent to the test vessel.

The sample and/or diluent may be added using a syringe and/or pipette. The method may further include entering a desired temperature or temperature range via a user interface. The method may additionally, or alternatively, include weighing the sample and entering the weight of the sample into the user interface 116, before beginning the analysis.

Where the analytical apparatus is a hydrogen sulphide analyser, the method may include purging hydrogen sulphide from the sample. Purging hydrogen sulphide from the sample may include agitating the sample by heat and/or air. Once the first assembly and second assembly have reached the desired temperature, a diluent may be added to the test vessel, and the test vessel may then be inserted into the second assembly 112. Air may then be pumped through the test vessel and on to a detector, via the filter cartridge, in order to purge the system substantially of contaminants before analysing the sample. Subsequently, air may be pumped through the apparatus such that the test vessel is bypassed. The sample may then be inserted into the test vessel. Redirecting the air flow such that it bypasses the test vessel whilst inserting the sample into the test vessel ensures there is no premature loss of hydrogen sulphide from the sample prior to the analysis commencing. Analysis of the sample may then begin. In order to analyse the sample, air may be pumped through the test vessel once again and any liberated hydrogen sulphide may then be carried on to the detector via the filter cartridge. The air flow through the apparatus may be diverted using valves, for example, solenoid valves. The filter cartridge may trap contaminants such as methyl mercaptans, dimethyl sulphide and other volatile chemicals prior to detection by the detector. The detector may include an electrochemical sensor. A liquid trap may be located between the test vessel and filter cartridge to remove liquid from the entrained air flow prior to reaching the filter cartridge. Flow sensors may detect air flow through the apparatus to ensure the air and hydrogen sulphide gas reaches the detector, to enable the air flow to be controlled, and/or to detect any flow problems. The method may be completed in a time period up to and including 5 minutes, 7 minutes, 9 minutes, 11 minutes, 13 minutes, 15 minutes, 17 minutes, 19 minutes, or any other suitable time. The result may be automatically calculated and displayed in mg/kg. The analytical results obtained by the analytical apparatus, one or more temperatures detected by the analytical apparatus, or any other information relevant to the analysis being carried out by the analytical apparatus may be automatically displayed on a display screen. The results of the analysis may be stored and later accessed by a user.

The skilled person will appreciate that the apparatus and methods described herein may be subject to various modifications without departing from the technical purpose and advantages of the respective apparatus and methods. For the avoidance of doubt, the scope of the invention is defined by the appended claims.

Claims

Claims 1. An analytical apparatus comprising: a first assembly; a second assembly; a heat sink; a first Peltier device located between the first assembly and the heat sink; and a second Peltier device located between the second assembly and the heat sink, wherein: the first Peltier device is configured to transfer heat from the first assembly to the heat sink to reduce and/or maintain the temperature of the first assembly below ambient temperature; and the second Peltier device is configured to convey heat from the heat sink to the second assembly to increase and/or maintain the temperature of the second assembly above ambient temperature.
2. An analytical apparatus according to claim 1, further comprising a first temperature sensor for measuring the temperature of the first assembly.
3. An analytical apparatus according to claim 1 or 2, further comprising a second temperature sensor for measuring the temperature of the second assembly.
4. An analytical apparatus according to any one of the preceding claims, wherein the first Peltier device is configured to transfer heat from the first assembly to the heat sink to reduce and subsequently maintain the temperature of the first assembly at a temperature below ambient temperature, and the second Peltier device is configured to convey heat from the heat sink to the second assembly to increase and subsequently maintain the temperature of the second assembly at a temperature above ambient temperature.
5. An analytical apparatus according to claim 4, wherein the first Peltier device is configured to reduce the temperature of the first assembly to, and maintain the temperature of the first assembly at, a temperature between -5 °C to -30°C.
6. An analytical apparatus according to claim 5, wherein the first Peltier device is configured to reduce the temperature of the first assembly to, and maintain the temperature of the first assembly at, -20°C
7. An analytical apparatus according to any one of claims 4 to 6, wherein the second Peltier device is configured to increase the temperature of the second assembly to, and maintain the temperature of the second assembly at, a temperature between 20°C to 100°C.
8. An analytical apparatus according to claim 7, wherein the second Peltier device is configured to increase the temperature of the second assembly to, and maintain the temperature of the second assembly at, 60°C.
9. An analytical apparatus according to any one of the preceding claims, wherein the first Peltier device and the second Peltier device are powered simultaneously.
10. An analytical apparatus according to any one of the preceding claims, further comprising a controller, said controller storing instructions which, when executed, at least partially operate the analytical apparatus.
11 An analytical apparatus according to any one of the preceding claims, wherein the first assembly, the second assembly and the heat sink are contained within a common housing.
12. An analytical apparatus according to claim 11, further comprising a first thermal insulating medium, wherein the first thermal insulating medium divides the common housing into a first compartment and a second compartment, wherein: the first compartment houses the first assembly and the second assembly; the second compartment houses the heat sink; and the first Peltier device and the second Peltier device are embedded within the first thermal insulating medium.
13. An analytical apparatus according to claim 12, further comprising a second thermal insulating medium, wherein the second thermal insulating medium is between the first assembly and the second assembly.
14. An analytical apparatus according to claim 12 or claim 13, further comprising a third thermal insulating medium, wherein the third thermal insulating medium is between the first and/or second assemblies and one or more outer walls of the first compartment.
15. An analytical apparatus according to any one of claims 12 to 14, wherein the second compartment comprises one or more walls, and the one or more walls comprise a vent.
16. An analytical apparatus according to any one of the preceding claims, wherein the first assembly comprises a first jacket for carrying a filter cartridge.
17. An analytical apparatus according to claim 16, wherein the first jacket is configured such that the first Peltier device is in indirect contact with the filter cartridge residing in the first jacket.
18. An analytical apparatus according to any one of the preceding claims, wherein the second assembly comprises a second jacket for carrying a sample test vessel.
19. An analytical apparatus according to claim 18, wherein the second jacket is configured such that the second Peltier device is in indirect contact with the test vessel residing in the second jacket.
20. An analytical apparatus according to any one of the preceding claims wherein the analytical apparatus is a hydrogen sulphide analyser.
21. A method of operating an analytical apparatus, the method comprising transferring heat from a first assembly to a heat sink using a first Peltier device to reduce and/or maintain the temperature of the first assembly below ambient temperature; and conveying heat from a heat sink to a second assembly using a second Peltier device to increase and/or maintain the temperature of the second assembly above ambient temperature.
22. A method of operating an analytical apparatus according to claim 21, comprising transferring heat from a first assembly to a heat sink using a first Peltier device to reduce and subsequently maintain the temperature of the first assembly at a temperature below ambient temperature; and conveying heat from a heat sink to a second assembly using a second Peltier device to increase and subsequently maintain the temperature of the second assembly at a temperature above ambient temperature.
23. A method of operating an analytical device according to claim 21 or 22, further comprising placing a filter cartridge into a first jacket of the first assembly; inserting a sample test vessel into a second jacket of the second assembly; transferring heat from the first assembly to the heat sink using the first Peltier device to reduce and subsequently maintain the temperature of the first assembly at a temperature between -5 °C and -30°C; and conveying heat from the heat sink to the first assembly using the second Peltier device to increase and subsequently maintain the temperature of the first assembly at a temperature between 20°C and 100°C.
24. A method of operating an analytical device according to claim 21 or 22, further comprising inserting a filter cartridge into a first jacket of the first assembly; inserting a sample test vessel into a second jacket of the second assembly; transferring heat from the first assembly to the heat sink using the first Peltier device to reduce and subsequently maintain the temperature of the first assembly at -20°C; and conveying heat from the heat sink to the first assembly using the second Peltier device to increase and subsequently maintain the temperature of the first assembly at 60°C.
25. A method of operating an analytical apparatus according to any one of claims 21 to 24, wherein the analytical apparatus is as defined in any one of claims 1 to 20.