Steam generator, thermal analyzer, and steam generation method

Abstract

The present invention provides a steam generator capable of generating high-purity steam at temperatures above 100°C under 1 atmosphere of pressure. [Solution] According to one aspect of the present invention, a steam generator 1 comprises a vaporization unit 3 having a porous body 32, a liquid supply unit 2 configured to supply water to the porous body, and a heating unit 4 configured to heat the porous body such that the first temperature at the water inlet portion of the porous body is lower than the second temperature at the portion downstream of the inlet portion in the direction of water flow.

Description

Technical Field

[0001] The present invention relates to a water vapor generator, a thermal analyzer, and a water vapor generation method.

Background Art

[0002] Patent Document 1 discloses a water vapor generator that generates water vapor. In this water vapor generator, water is heated by a heater and vaporized in a dry atmosphere to generate a mixed gas containing water vapor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In thermal analysis by a thermal analyzer or the like, analysis in a high-purity (for example, a volume ratio of 100 vol%) water vapor atmosphere may be required. However, since the above-described water vapor generator uses a dry gas, it is difficult to generate a high-purity water vapor gas.

Means for Solving the Problems

[0005] According to one aspect of the present invention, there is provided a water vapor generator including a vaporization unit having a porous body, a liquid supply unit configured to supply water to the porous body, and a heating unit configured to heat the porous body such that a first temperature of an inlet portion of water in the porous body is lower than a second temperature of a portion on the downstream side in the water flow direction from the inlet portion in the porous body.

[0006] With this configuration, the temperature gradient in the porous material suppresses sudden boiling of water in the liquid delivery and vaporization sections. As a result, high-purity water vapor at over 100°C can be generated under 1 atmosphere. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram of the steam generator 1 according to this embodiment. [Figure 2] This is a schematic diagram showing a modified example of the porous body 32. [Figure 3] This is a schematic diagram showing another example of the steam generator 1 according to this embodiment. [Figure 4] This is a schematic diagram showing yet another example of the steam generator 1 according to this embodiment. [Figure 5] This is a schematic diagram of the thermal analysis apparatus 100. [Figure 6] This is a flowchart illustrating an example of a method for generating water vapor. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to the drawings. The various features shown in the embodiments below can be combined with each other.

[0009] <Steam Generator 1> Figure 1 is a schematic diagram of the steam generator 1 according to this embodiment. The steam generator 1 is a device that generates steam at 100°C or higher under 1 atmosphere. In particular, the steam generator 1 can generate high-purity steam gas at 100°C or higher under 1 atmosphere and with a volume ratio of 100 vol%. The steam generator 1 comprises a liquid supply unit 2, a vaporization unit 3, and a heating unit 4.

[0010] <Liquid delivery section 2> The liquid supply unit 2 is configured to supply water to the vaporization unit 3 (specifically, the porous body 32, which will be described later). The liquid supply unit 2 is the source of water that is vaporized into water vapor by the vaporization unit 3. The liquid supply unit 2 includes a water reservoir 21, a pump 22, and a water supply channel 23.

[0011] The water reservoir 21 is configured to store water that is supplied to the vaporization unit 3. The water in the water reservoir 21 is sent to the vaporization unit 3 by the pump 22.

[0012] The pump 22 is preferably configured to supply water from the water reservoir 21 to the vaporization unit 3 at a predetermined flow rate (quantitative). With such a configuration, high-purity steam can be continuously generated at a quantitative rate. As such a pump 22, for example, a metering pump can be used that delivers a quantitative amount of liquid by pressing the tube constituting the flow path with rollers. However, the pump 22 may also have other structures (for example, a structure using a diaphragm, a structure using an electromagnet). The amount of liquid delivered by the pump 22 depends on the application of the steam, but for example, it is in the range of 0.001 ml / min to 3 ml / min.

[0013] Furthermore, the pump 22 is not necessarily limited to one that supplies water at a predetermined flow rate, but may also be one that supplies water at a predetermined pressure (constant pressure) (for example, an air pump).

[0014] The water supply channel 23 is connected to the discharge port of the pump 22 and the supply port of the vaporization chamber 31 of the vaporization unit 3. Water discharged from the pump 22 passes through the water supply channel 23 and is supplied into the vaporization chamber 31. The water supply channel 23 is made of a tube made of, for example, rubber.

[0015] <Vaporization section 3> The vaporization unit 3 is configured to vaporize water supplied from the liquid supply unit 2 to generate water vapor. The vaporization unit 3 has a vaporization chamber 31, a porous body 32, and an air supply passage 33.

[0016] The vaporization chamber 31 houses a porous body 32 inside. The water W supplied to the vaporization chamber 31 is supplied to the porous body 32 that is being heated by a heating unit 4 described later while being dispersed within the vaporization chamber 31. Further, the water W vaporizes within the porous body 32. Note that the vaporization chamber 31 itself (the internal space of the vaporization chamber 31) is also partially heated by the heating unit 4. Therefore, the temperature of the water W within the vaporization chamber 31 becomes higher than the temperature of the water W within the water supply passage 23.

[0017] In the water vapor generator 1, only water W is supplied to the vaporization chamber 31, and no other gas (dry gas) is supplied. That is, only the water supply passage 23 is connected to the vaporization chamber 31 as a fluid supply line.

[0018] The porous body 32 is a member having a large number of micropores through which water or water vapor can pass through). The material of the porous body 32 is not limited as long as it has heat resistance of at least 100°C. For example, metals, ceramics (e.g., alumina), etc. can be used as the material of the porous body 32. Further, the porous body 32 preferably has a certain degree of wettability from the viewpoint of promoting vaporization by attaching water to the surface.

[0019] The porous body 32 is preferably a cylindrical or columnar metal filter having a central axis along the flow direction FD of the water W. According to such a configuration, it becomes easier to form a temperature gradient by the heating unit 4 described later, so that high-purity water vapor can be generated more reliably. The water W or water vapor S flows through the inside of the porous body 32 along the central axis (i.e., the longitudinal direction) of the porous body 32.

[0020] Note that the porous body 32 may be, for example, a sintered body of metal particles or ceramic particles, or an aggregate of metal particles or ceramic particles (e.g., a container filled with particles).

[0021] It is presumed that the water W supplied into the vaporization chamber 31 enters the porous body 32 from the inlet 32A (upstream end) of the porous body 32, diffuses along the internal space of the porous body 32, and increases its surface area. This increase in surface area, as if the water W has permeated into the interior of the porous body 32, makes it easier for the water W to vaporize. As a result, the sudden boiling phenomenon, in which large bubbles are generated, is suppressed, and it becomes possible to generate water vapor S stably. The water vapor S, which is formed when water W vaporizes in the porous body 32, intermittently flows out from the outlet 32B (downstream end) of the porous body 32 toward the outside of the vaporization chamber 31.

[0022] The air supply passage 33 is configured to send the water vapor S generated in the porous body 32 to the supply destination (a device that uses water vapor). The air supply passage 33 is connected to the outlet of the vaporization chamber 31. The water vapor generated in the vaporization chamber 31 is supplied to the supply destination (i.e., discharged from the water vapor generator 1) by passing through the air supply passage 33. The air supply passage 33 is made of a metal pipe, such as stainless steel.

[0023] The air supply passage 33 may be directly connected to the outlet 32B of the porous body 32, or it may not be connected to the porous body 32 but only to the outlet of the vaporization chamber 31. The air supply passage 33 is connected in series with the water supply passage 23 via the vaporization chamber 31. In other words, in the steam generator 1, the water supply line and the gas supply line are formed on a single line without any confluence or branching passages.

[0024] <Heating section 4> The heating unit 4 is configured to heat the porous body 32 such that the first temperature at the water W inlet portion of the porous body 32 is lower than the second temperature at the downstream portion of the porous body 32, which is downstream of the inlet portion in the flow direction FD of the water W. This suppresses bumping in the vaporization chamber 31 or in the porous body 32. The heating unit 4 has a heater 41 for heating the porous body 32.

[0025] In conventional steam generators, when the entire porous body that vaporizes water is heated uniformly, the water vapor concentration around the porous body increases unless a dry atmosphere is present, making it difficult to stably vaporize water. Therefore, the supply of a drying gas becomes unavoidable, and it is not possible to generate high-purity steam gas. Furthermore, heating the entire porous body with a heater also raises the temperature of the liquid delivery section. If this causes bumping in the liquid delivery section, stable liquid delivery may not be possible. In contrast, in steam generator 1, a temperature gradient is provided in the porous body 32, enabling the stable generation of high-purity steam gas.

[0026] Here, the "water W inlet portion in the porous body 32" is typically the inlet 32A of the porous body 32, but is not limited to this. The "inlet portion" may be any portion between the inlet 32A and the center position P in the flow direction FD of the porous body 32. Furthermore, if the porous body 32 is cylindrical or columnar, the "inlet portion" may be the portion of the porous body 32 that is not radially covered by the heater 41.

[0027] Furthermore, the "downstream portion of the porous body 32 that is downstream of the inlet portion in the flow direction FD of the water W" is typically the outlet 32B of the porous body 32, but is not limited to this. The "downstream portion" may, for example, be the portion of the porous body 32 that includes the central position P in the flow direction FD, or it may be any portion between the central position P in the flow direction FD of the porous body 32 and the outlet 32B. Moreover, if the porous body 32 is cylindrical or columnar, the "downstream portion" may be the portion of the porous body 32 that is radially covered by the heater 41.

[0028] The heating unit 4 is preferably configured to heat the porous body 32 such that the temperature of the porous body 32 increases as it moves downstream from the inlet in the flow direction FD of the water W. With such a configuration, water vapor can be stably generated within the porous body 32, thereby suppressing the pressure effect of the water vapor on the liquid supply unit 2. As a result, water vapor can be generated stably and continuously.

[0029] Furthermore, the temperature change along the flow direction FD within the porous body 32 may be continuous (e.g., linear or curved) or stepwise (e.g., stepped).

[0030] The heater 41 is preferably a cylindrical heater positioned to radially cover the downstream portion of the porous body 32 (the portion where the second temperature is measured) and at least a portion of the air supply passage 33. With such a configuration, steam can be generated using a heater with a simple structure, thereby reducing the manufacturing cost and maintenance cost of the steam generator 1.

[0031] Specifically, the heater 41 surrounds the vaporization chamber 31 so as to cover the region of the porous body 32 downstream of the inlet 32A in the flow direction FD (the region including the outlet 32B). In other words, the heater 41 is positioned so as to overlap with the downstream region of the porous body 32 in the radial direction of the heater 41. As a result, the downstream region of the porous body 32 is indirectly heated by the heater 41 via the vaporization chamber 31.

[0032] In the vaporization chamber 31, the region upstream of the inlet 32A of the porous body 32 in the flow direction FD is not covered by the heater 41. In reduction, a portion of the vaporization chamber 31 downstream in the flow direction FD (including the connection portion with the air supply passage 33) is inserted into the heater 41. Therefore, the water W inlet portion (inlet 32A) of the porous body 32 is not covered by the heater 41 in the radial direction of the heater 41. The inlet portion of the porous body 32 is also heated by heat radiated from the heater 41, but the amount of heat received from the heater 41 is smaller than that received by the region of the porous body 32 covered by the heater 41. Therefore, in the porous body 32, the temperature of the inlet portion (first temperature) is lower than the temperature of the region covered by the heater 41 (second temperature).

[0033] Furthermore, the heater 41 covers the portion of the air supply passage 33 that connects to the vaporization chamber 31 (or porous body 32) and the region downstream of this connection portion in the flow direction FD. The end of the air supply passage 33 opposite to the vaporization chamber 31 (the outlet for water vapor S) may or may not be covered by the heater 41.

[0034] The heater 41 may have a structure that heats the inside to a uniform temperature, or it may have a structure in which the heating temperature changes continuously or in steps along the axial direction (the heating temperature increases downstream in the flow direction FD). The heating temperature of the heater 41 is set appropriately according to the amount of water W supplied (the amount of liquid delivered by the pump 22). Specifically, the heating temperature of the heater 41 is adjusted to a temperature at which water W does not vaporize upstream of the porous body 32, and water W vaporizes inside the porous body 32. The heating temperature of the heater 41 is such that the inside of the porous body 32 is at least 100°C or higher, for example, 180°C or higher.

[0035] <Modified form of porous material> In the example shown in Figure 1, the porous body 32 is columnar and is positioned away from the supply port (connection to the water supply channel 23) and the discharge port (connection to the air supply channel 33) of the vaporization chamber 31. In other words, a buffer space where the porous body 32 is not present is provided upstream of the inlet 32A of the porous body 32 and downstream of the outlet 32B. However, the shape and arrangement of the porous body 32 in Figure 1 is just one example.

[0036] Figure 2 is a schematic diagram showing a modified example of the porous body 32. As shown in Figure 2A, the outlet 32B of the porous body 32 may be in contact with the outlet of the vaporization chamber 31. In this case, a buffer space where the porous body 32 is not present is provided upstream of the inlet 32A of the porous body 32.

[0037] Furthermore, as shown in Figure 2B, the porous body 32 may have an inlet 32A that is in contact with the supply port of the vaporization chamber 31. In this case, a buffer space without the porous body 32 is provided downstream of the outlet 32B of the porous body 32. Also, as shown in Figure 2B, the porous body 32 may be a bottomed cylindrical body with a bottom wall on the upstream side. If the porous body 32 is a cylindrical body, the bottom wall may be provided on the downstream side, or on both the upstream and downstream sides.

[0038] <Other configurations> The steam generator 1 may further include a heat dissipation section or a cooling section that lowers the temperature of the water inlet portion in the porous body 32. For example, the steam generator 1 may cool the upstream portion of the porous body 32 by blowing air into the upstream portion of the vaporization chamber 31, supplying a refrigerant, or the like.

[0039] The steam generator 1 may further include a superheating section for superheating the steam discharged from the vaporization section 3. Alternatively, the steam may be superheated by a heater 41. This makes it possible to generate high-purity steam at temperatures exceeding 100°C.

[0040] Figure 3 is a schematic diagram showing another example of the steam generator 1 according to this embodiment. The steam generator 1 in Figure 3 further comprises a gas supply unit 5 in addition to a liquid supply unit 2, a vaporization unit 3, and a heating unit 4. The gas supply unit 5 is configured to supply a dry gas G to the steam S generated in the vaporization unit 3. The dry gas G is, for example, nitrogen gas (N2 gas). The gas supply unit 5 has a gas introduction passage 51.

[0041] The gas introduction passage 51 is connected to the air supply passage 33 of the vaporization section 3. The gas introduction passage 51 supplies dry gas G supplied from the gas supply source into the air supply passage 33 and mixes it with water vapor S. The gas introduction passage 51 is connected, for example, to the part of the air supply passage 33 that is heated (covered) by the heater 41. In the water vapor generator 1 of Figure 3, the concentration of water vapor gas generated by the water vapor generator 1 can be adjusted by controlling the flow rate of dry gas G and the amount of water W supplied by the pump 22 (i.e., controlling the mixing ratio of dry gas G).

[0042] Figure 4 is a schematic diagram showing yet another example of the steam generator 1 according to this embodiment. The steam generator 1 in Figure 4 further comprises a temperature control unit 6 in addition to a liquid supply unit 2, a vaporization unit 3, a heating unit 4, and a gas supply unit 5. The temperature control unit 6 is configured to adjust the temperature of the steam gas, which is a mixture of the steam S generated in the vaporization unit 3 and a dry gas G. The temperature control unit 6 has a heating and cooling unit 61.

[0043] The heating / cooling unit 61 is positioned to radially cover the portion of the air supply passage 33 downstream of the connection to the gas introduction passage 51, more specifically, the portion downstream of the portion heated (covered) by the heater 41. The heating / cooling unit 61 heats, maintains the temperature of, or cools the water vapor gas in the air supply passage 33. In the water vapor generator 1 of Figure 4, by controlling the temperature of the heating / cooling unit 61 in conjunction with controlling the mixing ratio of the dry gas G, it is possible to generate water vapor gas at any desired temperature and humidity.

[0044] <Thermal analyzer 100> Figure 5 is a schematic diagram of the thermal analyzer 100. The thermal analyzer 100 is a device that analyzes changes in the state of a sample when it is heated (for example, thermogravimetric analysis (TG), thermomechanical analysis (TMA), etc.), changes in the state of gases separated from the sample, etc. The thermal analyzer 100 comprises a steam generator 1, a measuring device 200, and a control device 300.

[0045] <Measuring device 200> The measuring device 200 includes a heating furnace (electric furnace) for heating the sample, a temperature measuring device for measuring the temperature of the sample or atmosphere, a weight measuring device for measuring the weight of the sample, an imaging device for acquiring an image of the sample, a load device for applying a load to the sample, and an analytical device for analyzing the generated gas.

[0046] The measuring device 200 is configured to measure the change in state of a sample when it is heated in an atmosphere of water vapor supplied from the water vapor generator 1. Specifically, the water vapor generated by the water vapor generator 1 is supplied into the heating furnace in which the sample is placed, and humidified thermal analysis is performed in the measuring device 200. With this configuration, it is possible to perform state changes of the sample (thermogravimetric analysis, thermomechanical analysis, etc.) in a high-purity water vapor atmosphere of 100°C or higher at 1 atmosphere. As a result, it becomes possible to discover new properties of the sample.

[0047] Furthermore, the steam generator 1 can supply superheated steam to the measuring device 200 while adjusting the temperature and flow rate. Superheated steam has high heat transfer properties due to combined heat transfer (radiation, convection, and condensation), and superheated steam above 170°C dries faster than air. Therefore, by supplying high-purity superheated steam with a volume ratio of 100 vol% to the measuring device 200, thermal analysis becomes possible in low-oxygen or oxygen-free environments.

[0048] <Control device 300> The control device 300 is configured to control the heating furnace of the measuring device 200, record and analyze data acquired by various instruments of the measuring device 200, and so on. The control device 300 may also be configured to control the amount of steam supplied to the steam generator 1.

[0049] The control device 300 is an information processing device having a processor, a communication unit, a storage unit, a display unit, an input unit, etc. The control device 300 executes functions (steps) for controlling the measuring device 200 by having the processor read a program.

[0050] 4. Effect According to the steam generator 1, the temperature gradient in the porous body 32 suppresses the sudden boiling of water within the porous body 32. As a result, it is possible to generate high-purity steam at temperatures above 100°C under 1 atmosphere.

[0051] Although embodiments of the present invention have been described above, the present invention is not limited thereto and can be modified as appropriate without departing from the technical spirit of the invention.

[0052] 5. Others The above embodiment may also be a steam generation method. This steam generation method comprises the steps of supplying water to the porous body 32 and heating the porous body 32 such that the first temperature at the water inlet portion of the porous body 32 is lower than the second temperature at the downstream portion of the porous body 32, which is downstream of the inlet portion in the direction of water flow.

[0053] Figure 6 is a flow chart showing an example of a steam generation method. In this steam generation method, first, water is supplied to the porous body 32 by the liquid supply unit 2 (step S110). At the same time, the porous body 32 is heated by the heating unit 4 (step S120). Alternatively, the porous body 32 may be preheated before supplying water. After supplying water and heating the porous body 32, the steam generated in the vaporization unit 3 is supplied to the destination (for example, the measuring device 200).

[0054] The steam generator 1 can be used for purposes other than the thermal analyzer 100. For example, the steam generator 1 can be used to supply steam as a treatment gas for degreasing ceramic molded bodies (removal of binders), etc.

[0055] The water vapor generator 1 can also be used as a gas generator that produces high-purity gas obtained by vaporizing liquids other than water (for example, alcohol).

[0056] The product may be provided in any of the following embodiments.

[0057] (1) A steam generator comprising: a vaporization section having a porous body; a liquid supply section configured to supply water to the porous body; and a heating section configured to heat the porous body such that the first temperature of the water inlet portion of the porous body is lower than the second temperature of the portion of the porous body downstream of the inlet portion in the direction of water flow.

[0058] With this configuration, the temperature gradient within the porous material suppresses the sudden boiling of water within the porous material. As a result, it is possible to generate high-purity water vapor at temperatures above 100°C under 1 atmosphere of pressure.

[0059] (2) A steam generator as described in (1) above, wherein the heating section is configured to heat the porous body such that the temperature of the porous body increases as it moves downstream from the inlet in the flow direction.

[0060] With this configuration, water vapor can be stably generated within the porous body, thereby suppressing the pressure effect of water vapor on the liquid delivery section. As a result, water vapor can be generated stably and continuously.

[0061] (3) A steam generator according to (1) or (2) above, wherein the vaporization section has an air supply passage configured to send out steam generated in the porous body, and the heating section has a cylindrical heater arranged to radially cover the portion of the porous body downstream in the flow direction from the inlet portion and at least a part of the air supply passage.

[0062] With this configuration, steam can be generated using a heater with a simple structure, thereby reducing the manufacturing and maintenance costs of the steam generator.

[0063] (4) A steam generator according to any one of (1) to (3) above, wherein the liquid supply unit has a pump that supplies the water at a predetermined flow rate.

[0064] With this configuration, high-purity water vapor can be continuously generated in a fixed quantity.

[0065] (5) A steam generator according to any one of (1) to (4) above, wherein the porous body is a cylindrical or columnar metal filter having a central axis along the direction of water flow.

[0066] This configuration makes it easier to create a temperature gradient in the heating section, thus enabling the more reliable generation of high-purity steam.

[0067] (6) A thermal analyzer comprising a steam generator described in any one of (1) to (5) above, and a measuring device configured to measure the change in state when a sample is heated in an atmosphere of steam supplied from the steam generator.

[0068] This configuration allows for the analysis of sample phase changes (thermogravimetric analysis, thermomechanical analysis, etc.) under a high-purity water vapor atmosphere exceeding 100°C at 1 atmosphere. As a result, it becomes possible to discover new properties of the sample.

[0069] (7) A method for generating steam, comprising the steps of: supplying water to a porous body; and heating the porous body such that the first temperature at the water inlet portion of the porous body is lower than the second temperature at the portion of the porous body downstream of the inlet portion in the direction of water flow.

[0070] With this configuration, the temperature gradient within the porous material suppresses the sudden boiling of water within the porous material. As a result, it is possible to generate high-purity water vapor at temperatures above 100°C under 1 atmosphere of pressure. Of course, this is not always the case.

[0071] Finally, while various embodiments relating to this disclosure have been described, these are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of symbols]

[0072] 1: Steam generator 2: Liquid delivery section 3: Vaporization section 4: Heating part 5: Gas supply department 6: Temperature adjustment section 21: Water storage 22: Pump 23: Water supply channel 31: Vaporization chamber 32: Porous material 32A: Entrance 32B: Exit 33: Air supply duct 41: Heater 51: Gas introduction route 61: Heating / cooling device 100:Thermal analysis device 200: Measuring device 300: Control device

Claims

1. A water vapor generator, A vaporization section having a porous material, A liquid supply unit configured to supply water to the porous body, A heating unit configured to heat the porous body such that the first temperature at the water inlet portion of the porous body is lower than the second temperature at the portion downstream of the water flow in the porous body from the inlet portion, A steam generator equipped with the following features.

2. In the steam generator according to claim 1, A steam generator wherein the heating section is configured to heat the porous body such that the temperature of the porous body increases as it moves downstream from the inlet in the flow direction.

3. In the steam generator according to claim 1, The vaporization section has an air supply passage configured to send out the water vapor generated in the porous body, The heating section is a steam generator having a portion of the porous body downstream in the flow direction from the inlet portion and a cylindrical heater arranged to radially cover at least a portion of the air supply passage.

4. In the steam generator according to claim 1, The liquid supply unit is a steam generator having a pump that supplies the water at a predetermined flow rate.

5. In the steam generator according to claim 1, A steam generator, wherein the porous body is a cylindrical or columnar metal filter having a central axis along the direction of water flow.

6. A thermal analysis device, A steam generator according to any one of claims 1 to 5, A measuring device configured to measure the change in state when a sample is heated in an atmosphere of water vapor supplied from the water vapor generator, A thermal analyzer equipped with the following features.

7. A method for generating water vapor, The process of supplying water to a porous body, A step of heating the porous body such that the first temperature at the water inlet portion of the porous body is lower than the second temperature at the portion downstream of the water flow in the direction of water flow, A method for generating water vapor, comprising the following features.

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