Moisture meter

Abstract

A heated drying type moisture meter capable of diagnosing the state of the device also considering factors other than the quality measuring section is provided. The moisture meter (100) comprises: a quality measuring section (2) that measures the quality of a test material; a heating section (3) that heats the test material; a control operation section (5) that controls the heating section (3) to heat until the quality change of the test material becomes below a prescribed threshold value, and calculates the moisture rate of the test material based on the quality change before and after heating; a clock (4) that measures the heating time; and a storage section (8); the control operation section (5) comprises: a standard material measuring section (52) that measures the moisture rate of a standard material for inspection as the test material, and measures the heating time; and an abnormality diagnosing section (53) that evaluates the measured moisture rate with reference to the theoretical moisture rate of the standard material, and diagnoses the presence or absence of an abnormality of the quality measuring section (2), and compares the measured heating time with a prescribed time stored in advance in the storage section (8) as a set heating time, and diagnoses the presence or absence of an abnormality of the heating section (3).

Description

Technical Field

[0001] This invention relates to moisture meters, and more specifically, to a heat-drying moisture meter. Background Technology

[0002] Previously, as one of the devices for measuring the moisture content of a sample, a heat-drying moisture meter is known (for example, Patent Document 1). A heat-drying moisture meter is a device that measures the moisture content of a sample by heating the sample to evaporate the moisture in the sample and by measuring the change (reduction) in the mass of the sample before and after heating.

[0003] Heated drying moisture meters are relatively inexpensive devices, and they can measure moisture content in a short time for a wide range of samples. Therefore, heated drying moisture meters are widely used. In this specification, unless otherwise specified, "moisture meter" refers to a heated drying moisture meter.

[0004] Patent Document 1 discloses a moisture meter configured to use a substance with a known moisture content, such as sodium tartrate dihydrate (C4H4Na2O6·2H2O, hereinafter simply referred to as "sodium tartrate"), as a standard substance for calibrating the device's performance. It is known that sodium tartrate releases moisture by undergoing an irreversible crystallization process when heated to approximately 160°C for about 10 minutes.

[0005] The moisture meter in Patent Document 1 compares the measured moisture content of a standard substance with the theoretical moisture content of the same standard substance that is pre-stored in a storage unit, evaluates the comparison result based on a pre-set evaluation standard, and calibrates the mass measurement unit based on the evaluation result so that the measured moisture content equals the theoretical moisture content.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2003-344255 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, the performance of a moisture meter is affected not only by the condition of the mass measuring section, but also by other factors, especially the condition of the heating section.

[0011] Specifically, in cases where the halogen lamp used as the heating mechanism or the glass cover used to protect the sample is dirty or the halogen lamp itself is malfunctioning, there is a problem that heating may not be performed according to the performance, and the measurement time may become longer.

[0012] Therefore, there is a need for the development of a moisture meter that can diagnose the condition of the device by taking into account factors other than the quality measurement section, especially the condition of the heating section.

[0013] The present invention was made in view of the following situation, and the object is to provide a heated drying type moisture meter that can also take into account factors other than the quality measurement unit to diagnose the state of the device.

[0014] Institutions used to solve problems

[0015] To achieve the above objectives, a moisture meter according to a technical solution of the present invention is characterized by comprising: a mass measuring unit for measuring the mass of a sample placed on a weighing dish; a heating chamber configured to be openable and closable, in which the weighing dish is disposed; a heating unit disposed in the heating chamber for heating the sample; a control calculation unit for controlling the heating unit to heat the sample until the mass change of the sample is below a predetermined threshold, and calculating the moisture content of the sample based on the mass change of the sample before and after heating; a clock for measuring the heating time; and a storage unit; the control calculation unit comprises: a standard substance measuring unit for measuring the moisture content of a standard substance used for testing the sample and measuring the heating time; and an anomaly diagnosis unit for evaluating the measured moisture content based on the theoretical moisture content of the standard substance, diagnosing the presence or absence of an anomaly in the mass measuring unit, and comparing the measured heating time with a predetermined time stored in the storage unit as a set heating time to diagnose the presence or absence of an anomaly in the heating unit.

[0016] In the above technical solution, preferably, the abnormality diagnosis unit determines that the heating unit is abnormal when the measured heating time is longer than the specified time.

[0017] Furthermore, in the above technical solution, it is preferred that the above standard substance is sodium tartrate dihydrate.

[0018] Furthermore, in the above technical solution, it is preferable to include a display unit; the abnormality diagnosis unit displays the location of the abnormality and a message to the user informing them of the corresponding countermeasures as a diagnosis result on the display unit.

[0019] Invention Effects

[0020] In heated drying moisture meters, the condition of the device can be diagnosed by taking into account factors other than the mass measurement section, especially the condition of the heating section. Attached Figure Description

[0021] Figure 1 This is a block diagram illustrating the structure of a moisture meter according to an embodiment of the present invention.

[0022] Figure 2 This is a 3D view of the moisture meter with the heating chamber lid open.

[0023] Figure 3 This is a flowchart of the operation of the moisture meter in the sample measurement mode.

[0024] Figure 4 This is a flowchart of the operation of the moisture meter in the initial setting mode.

[0025] Figure 5 This is a flowchart of the standard substance measurement process performed by the moisture meter.

[0026] Figure 6 This is a flowchart of the operation of the moisture meter in its inspection mode.

[0027] Figure 7 This is a diagram showing an example of an abnormal diagnostic result in the inspection mode of this moisture meter.

[0028] Figure 8 This is a diagram showing an example of an abnormal diagnostic result in the inspection mode of this moisture meter. Detailed Implementation

[0029] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited thereto. Furthermore, in each embodiment, the same reference numerals are used for the same structures and repeated descriptions are omitted where appropriate.

[0030] (Implementation Method)

[0031] Figure 1 This is a block diagram illustrating the structure of a moisture meter 100 according to an embodiment of the present invention. Figure 2 This is a perspective view showing the heating chamber C with its cover 9 open in the moisture meter 100. (Example) Figure 1 As shown, the moisture meter 100 includes a mass measurement unit 2, a heating unit 3, a clock 4, a control and calculation unit 5, an input unit 6, a display unit 7, and a storage unit 8.

[0032] The mass measuring unit 2 is a mass meter, such as an electromagnetic balance mass sensor, connected to the weighing dish 2a on which the sample is placed. The mass measuring unit 2 measures the mass of the sample placed in the weighing dish 2a. Furthermore, the mass measuring unit 2 is housed inside the moisture meter body 10.

[0033] Weighing dish 2a is configured by... Figure 2 The heating chamber C is sealed by closing the lid 9, which is shown as an openable / closable type. The weighing dish 2a is equipped with a handle 2b, which allows it to be detached from the mass measuring unit 2. The heating chamber C is configured as a space divided by the upper part of the moisture meter body 10 and the lid 9, and accommodates the weighing dish 2a.

[0034] The heating unit 3 includes a heating mechanism 3a such as a halogen lamp or a Joule-heated resistance wire, and a temperature sensor (not shown). The heating mechanism 3a is controlled by the control and calculation unit 5 based on the output from the temperature sensor to heat the sample.

[0035] The heating mechanism 3a is housed inside the cover 9 of the heating chamber C. The cover 9 has a container-shaped glass cover 9a that covers the weighing dish 2a in order to prevent the sample from coming into contact with the heating mechanism 3a.

[0036] Clock 4, controlled by the control and calculation unit 5, measures the heating time from the start of heating by heating unit 3 to the stop of heating. Furthermore, clock 4 is, for example, installed in the control and calculation unit 5 as a system clock.

[0037] The control and arithmetic unit 5 is a microcomputer equipped with a CPU (Central Processing Unit), ROM (Read-Only Memory), and RAM (Random Access Memory) for performing arithmetic operations.

[0038] The control and calculation unit 5 is connected to the mass measurement unit 2, the heating unit 3, the clock 4, the input unit 6, the display unit 7, and the storage unit 8, and performs various actions to enable the moisture meter 100 to function.

[0039] The control and calculation unit 5 controls each part to execute measurements in sample measurement mode, initial setting check mode, and check mode. Sample measurement mode is the normal operating mode of the moisture meter 100, used to measure the moisture content of a sample whose moisture content is desired. Check mode is used to diagnose the condition of the moisture meter 100. Initial setting check mode is used to obtain the initial setting value (setting heating time) for the heating time used in the check mode.

[0040] The control and calculation unit 5 also includes a sample measurement unit 51, a standard substance measurement unit 52, and an anomaly diagnosis unit 53. Each functional unit is implemented, for example, by a program.

[0041] In the sample measurement mode, the sample measurement unit 51 controls the heating unit 3, heats the sample while monitoring the mass change of the sample, and stops the heating unit 3 when the mass change rate of the sample is below a predetermined threshold.

[0042] In addition, the sample measurement unit 51 uses the mass measurement value of the sample before heating and the mass measurement value after heating to calculate the moisture content M of the sample using the following formula 1.

[0043] M(%)=[[(W1-W2)] / W1]×100…(Equation 1)

[0044] (Here, W1 is the mass measurement value before heating, and W2 is the mass measurement value after heating.)

[0045] In both the initial setting mode and the inspection mode, the standard substance measurement unit 52, like the sample measurement unit 51, measures the moisture content of the standard substance (hereinafter referred to as "standard substance") used for inspection, and measures the heating time required to measure the moisture content of the standard substance.

[0046] In inspection mode, the abnormality diagnosis unit 53 determines whether the measured moisture content Mi of the standard substance is within the specified range based on the theoretical moisture content Mt of the standard substance, and determines whether there is an abnormality in the quality measurement unit 2.

[0047] In addition, in inspection mode, the abnormality diagnosis unit 53 compares the measured heating time Ti with the set heating time Ts stored in the initial inspection setting mode at the time of factory shipment to determine whether there is an abnormality in the heating unit 3.

[0048] Input section 6 includes operation buttons such as start button, stop button, up and down buttons, selection button, and confirmation button, for indicating the start and stop of measurement, setting the mode, and selecting the action.

[0049] Display unit 7 is a liquid crystal display (LCD) that displays measurement results, mode selection screens, messages, etc. Alternatively, input unit 6 and display unit 7 can be integrated into a single touch panel display.

[0050] The storage unit 8 is, for example, a non-volatile semiconductor memory such as flash memory. In the storage unit 8, settings for the heating temperature and sample loading amount, corresponding to the theoretical moisture content of the standard substance and the standard substance itself, are stored to enable appropriate testing. Furthermore, the heating time of the standard substance measured in the initial test setting mode is stored. Additionally, the storage unit 8 stores messages displayed on the display unit 7 for the anomaly diagnosis unit 53 to notify the user of the diagnostic results.

[0051] Next, the standard substances used in the abnormal diagnosis of the moisture meter 100 will be described. The standard substances are not limited to these, but substances shown in Table 1 can be used, for example. Sodium tartrate is particularly preferred due to its high stability and ease of handling. The theoretical moisture content and suitable heating temperatures for measuring the moisture content are known for these substances.

[0052] [Table 1]

[0053] Examples of usable standard substances

[0054] substance name Theoretical moisture content Sodium tartrate dihydrate 15.66％ Sodium citrate dihydrate 12.4％ Sodium tungstate dihydrate 10.92％ Calcium bromide dihydrate 15.26％ Calcium chloride dihydrate 32.41％ Sodium dihydrogen phosphate dihydrate 20.23％

[0055] Only one standard substance needs to be set, but multiple standards can also be set. In this case, the storage unit 8 stores the theoretical moisture content, appropriate heating temperature, and sample loading amount of multiple standard substances according to the codes assigned to each substance.

[0056] Next, the operation of the moisture meter 100 in the sample measurement mode, the initial setting mode, and the inspection mode will be explained.

[0057] (Sample Measurement Mode)

[0058] Figure 3 This is a flowchart of the operation of the moisture meter 100 in its normal operating state, i.e., in sample measurement mode.

[0059] In the case of measuring a sample, in step S101, the user sets the moisture meter 100 to sample measurement mode from the input unit 6. If the normally used mode is set to sample measurement mode in advance, step S101 can be omitted.

[0060] Next, in step S102, the user places the sample on the weighing dish 2a and closes the lid 9. After setting the heating temperature from the input unit 6, the user presses the measurement start button.

[0061] Next, in step S103, the sample measuring unit 51 begins heating the heating unit 3. Through heating, the moisture in the sample gradually evaporates, and the mass measurement value of the sample measured by the mass measuring unit 2 decreases over time.

[0062] The sample measurement unit 51 monitors the change in the mass measurement value. In step S104, when the change in the mass measurement value falls below a preset threshold (in the case of "Yes"), the process proceeds to step S105. In step S105, the sample measurement unit 51 stops heating of the heating unit 3, calculates the moisture content M according to Formula 1, displays the calculation result on the display unit 7, and ends the measurement.

[0063] (Check initial settings mode)

[0064] Figure 4 This is a flowchart illustrating the operation of the moisture meter 100 in the initial setting mode check. The initial setting mode check is typically performed during factory shipment. Furthermore, sodium tartrate is set as a standard substance.

[0065] In step S201, if the manufacturer's operator sets the initial value setting mode from the input unit 6, then in step S202, the moisture meter 100 performs a measurement of the standard substance.

[0066] While referring to Figure 5The detailed operation of step S202, the measurement of the standard substance, is explained below. First, if the measurement of the standard substance begins, in step S301, the standard substance measurement unit 52 displays the sample loading amount and heating temperature setting, which are pre-stored in the storage unit 8 and are suitable for inspection, corresponding to sodium tartrate, on the display unit 7 as a message such as the following.

[0067] Standard substance: Sodium tartrate

[0068] (a) Heating temperature set to 160℃

[0069] (b) Sample weight approximately 5g”

[0070] Next, in step S302, based on the instructions of the display unit 7, the operator places approximately 5g of sodium tartrate on the weighing dish 2a, closes and sets the lid 9, sets the heating temperature to 160°C, and begins the measurement.

[0071] In addition to being set manually by the operator, the heating temperature can also be automatically set by the moisture meter 100 according to the type of standard substance.

[0072] Next, in step S303, the standard substance measuring unit 52 begins heating the heating unit 3. Similar to the sample measuring mode, the standard substance measuring unit 52 measures the heating time T while monitoring the change in the mass measurement value of the mass measuring unit 2.

[0073] Next, in step S304, when the change in the mass measurement value falls below a preset threshold, in step S305, the standard substance measuring unit 52 stops the heating of the heating unit 3 and calculates the moisture content M of the standard substance according to Formula 1.

[0074] Meanwhile, in step S306, the standard substance measuring unit 52 calculates the time from the start of heating to the end of heating, i.e., the heating time T, and then proceeds to step S203.

[0075] In step S203, the display unit 7 displays the moisture content M and the heating time T.

[0076] Next, in step S204, the storage unit 8 stores the calculated heating time T as the set heating time Ts and ends the process.

[0077] (Inspection Mode)

[0078] Figure 6 This is a flowchart illustrating the operation of the moisture meter 100 in inspection mode. Inspection mode can be executed whenever the user of the moisture meter 100 wants to check for any abnormalities in the moisture meter 100.

[0079] In step S401, if the user sets the inspection mode from the input unit 6, then in step S402, the standard substance measurement unit 52 calculates the measured moisture content Mi and the measured heating time Ti of the standard substance in the same way as in steps S301 to S306.

[0080] Next, in step S403, the standard substance measurement unit 52 temporarily saves the measured moisture content Mi and the measured heating time Ti measured in step S402.

[0081] Next, in step S404, the anomaly diagnosis unit 53 begins anomaly diagnosis. In step S405, the anomaly diagnosis unit 53 determines whether the measured moisture content Mi of the standard substance calculated in step S402 is within a specified range based on the theoretical moisture content Mt. For example, when using sodium tartrate, it determines whether the moisture content is within the range of 15.0 to 16.0.

[0082] The range specified based on the theoretical moisture content Mt is set according to the type of standard material. For example, it can also be set as theoretical moisture content ±1%.

[0083] In step S405, if the measured moisture content Mi is within the specified range (yes), in step S406, the anomaly diagnosis unit 53 determines that the quality measurement unit 2 has no anomaly.

[0084] On the other hand, in step S405, if the measured moisture content Mi is outside the specified range (no), in step S407, the anomaly diagnosis unit 53 determines that the quality measurement unit 2 has an anomaly.

[0085] Next, in step S408, the anomaly diagnosis unit 53 compares the measured heating time Ti in step S402 with the specified time Tp stored as the set heating time Ts in the initial setting mode of the inspection, and determines whether the measured heating time Ti is less than or equal to the specified time Tp.

[0086] In addition, the specified time Tp may not be exactly the same as the set heating time Ts, but may be a range of some degree, such as Ts ± 30 seconds.

[0087] In step S408, if the measured heating time Ti is less than or equal to the specified time Tp, in step S409, the abnormality diagnosis unit 53 determines that the heating unit 3 has no abnormality.

[0088] In step S408, if the measured heating time Ti is greater than the specified time Tp (no), in step S410, the abnormality diagnosis unit 53 determines that the heating unit 3 is abnormal. Possible causes of the abnormality in the heating unit 3 include dirt on the glass cover 9a, dirt on the heating mechanism 3a, or a malfunction of the heating mechanism 3a.

[0089] Next, in step S411, the abnormality diagnosis unit 53 displays the diagnosis results on the display unit 7 and the process ends.

[0090] Figure 7 , Figure 8 This is an example of a display showing the diagnostic results on display unit 7. In each display, the button on the image indicated by the black arrow 7a (emphasized in gray in the figure) is the currently selected button, and selecting this button changes the display screen.

[0091] Figure 7 (A) is a display example where, in step S407, it is determined that the mass measuring unit 2 is abnormal, and in step S409, it is determined that the heating unit 3 is not abnormal. If the user... Figure 7 If you select "Next" in state (A), then the abnormal diagnosis section 53 will proceed as follows: Figure 7 (B-1) Display a message on display unit 7 confirming whether a calibration has been performed.

[0092] Without calibration, the user selects "No". Therefore, the anomaly diagnosis unit 53 determines that calibration is required, such as... Figure 7 As in (B-2), a message urging the user to perform the calibration is displayed on the display unit 7. The user, having acknowledged the message, performs the calibration and selects the "End" button. Alternatively, the calibration can be configured to be performed automatically.

[0093] After calibration, the user verifies whether the anomaly has been eliminated by performing the measurement again in check mode. If the anomaly is not eliminated even after calibration, such as... Figure 7 In the case of (C-1), the user selects "Yes".

[0094] Therefore, the anomaly diagnosis unit 53 determined that, despite the calibration, the anomaly in the quality measurement unit 2 had not been eliminated, and the moisture meter 100 was in need of repair. Figure 7 As shown in (C-2), a message urging repair is displayed. The user then requests repair based on the message.

[0095] Figure 8 (A) is a display example where, in step S406, it is determined that the mass measuring unit 2 is normal, and in step S410, it is determined that the heating unit 3 is abnormal. If the user... Figure 8 If you select "Next" in state (A), the abnormality diagnosis unit 53 will display on the display unit 7 the possible causes, such as dirt on the glass cover 9a. Figure 8 (B) A message urging the cleaning of the glass cover 9a is displayed. After confirming the message, the user cleans the glass cover 9a and selects "Next".

[0096] Therefore, the abnormality diagnosis department 53 considers dirt in the heating mechanism 3a as one of the possible causes, such as... Figure 8 (C) In this way, a message urging the cleaning of the halogen lamp (heating mechanism 3a) is displayed on the display unit 7. After confirming the message, the user cleans the halogen lamp and selects "Next".

[0097] Therefore, the abnormality diagnosis department 53, regarding the possible causes of the malfunction of the heating mechanism 3a, such as... Figure 8 (D) In ​​this manner, a message urging the replacement of the halogen lamp (heating mechanism 3a) is displayed on the display unit 7. The user who has confirmed the message requests the replacement of the halogen lamp.

[0098] In addition, Figure 7 (A)~ Figure 8 (D) During each stage, the display unit 7 shows an "End" button. Therefore, the user can, according to their own judgment, end the diagnostic result display midway and repeat the measurement in the examination mode.

[0099] For example, in Figure 8 In (B), if the user is certain that the dirt on the glass cover 9a is the cause, and cleaning the glass cover 9a confirms that the abnormality of the heating unit 3 has been eliminated, the user can choose to end the test and repeat the measurement in the inspection mode. If this is done, the time spent on the inspection can be shortened.

[0100] In the moisture meter 100 of this embodiment, the configuration is such that, in inspection mode, the moisture content of a standard substance is measured, and the measured moisture content Mi is evaluated based on the theoretical moisture content Mt of the standard substance to diagnose the presence or absence of abnormalities in the mass measurement unit 2. Furthermore, the heating time required for measuring the moisture content of the standard substance is measured, and the measured heating time Ti is compared with a predetermined time Tp, which is the set heating time Ts used for factory shipment, to determine any abnormalities in the heating unit 3. As a result, the condition of the moisture meter 100 can be diagnosed by considering factors other than the mass measurement unit 2, particularly the condition of the heating unit 3.

[0101] In particular, the configuration is such that, in the diagnosis of abnormalities in the heating unit 3, the measured heating time Ti is compared with a predetermined time Tp, which is a set heating time Ts. When the measured heating time Ti is longer than the predetermined time Tp, it is determined that there is an abnormality in the heating unit 3. As a result, it is possible to diagnose the existence of adverse conditions such as dirt on the glass cover 9a or the halogen lamp (heating mechanism 3a), or a malfunction of the halogen lamp (heating mechanism 3a), which would result in a longer measurement time.

[0102] Furthermore, in the moisture meter 100 of this embodiment, the abnormality diagnosis unit 53 sequentially displays the location of the abnormality and a message informing the user of the cause and corresponding countermeasures on the display unit 7 as diagnostic results. As a result, by acting according to the display, the user can reliably handle the abnormality even without special knowledge.

[0103] The preferred embodiments of the present invention have been described above, but the above embodiments are only examples of the present invention, and they can be combined based on the knowledge of those skilled in the art, and such forms are also included in the scope of the present invention.

[0104] Label Explanation

[0105] 2: Quality Measurement Department

[0106] 2a: Weighing dish

[0107] 3: Heating section

[0108] 4: Clock

[0109] 5: Control and arithmetic unit

[0110] 7: Display Section

[0111] 8: Storage Department

[0112] 52: Standard Material Measurement Department

[0113] 53: Abnormal Diagnosis Department

[0114] 100: Moisture meter

[0115] C: Heating chamber

Claims

1. A moisture meter characterized by comprising: a mass measuring section that measures a mass of a sample placed on a weighing pan; a heating chamber that is configured to be openable and closable, and in which the weighing pan is disposed; a heating section that is disposed in the heating chamber, and heats the sample; a control operation section that controls the heating section, performs heating until the mass of the sample changes to be below a predetermined threshold value, and calculates a moisture content of the sample based on a change in the mass of the sample before and after heating; a clock that measures a heating time; and a storage section, wherein the control operation section comprises: a standard substance measuring section that measures a moisture content of a standard substance for inspection as the sample, and measures the heating time; and an abnormality diagnosing section that evaluates a measured moisture content based on a theoretical moisture content of the standard substance, diagnoses presence or absence of an abnormality of the mass measuring section, compares a measured heating time with a predetermined time that is a set heating time and is stored in the storage section in advance, and diagnoses presence or absence of an abnormality of the heating section, wherein the measured heating time is a time from a start of heating to a time when the mass of the sample changes to be below the predetermined threshold value, wherein the abnormality diagnosing section determines that the heating section has an abnormality when the measured heating time is longer than the predetermined time, wherein the heating section comprises a heating mechanism, wherein the heating chamber comprises a glass cover for preventing the sample from contacting the heating mechanism, and wherein the abnormality is a contamination of the heating mechanism, a contamination of the glass cover, or a failure of the heating mechanism.

2. The moisture meter according to claim 1, wherein the standard substance is sodium tartrate dihydrate.

3. The moisture meter according to claim 1, characterized by comprising a display section, wherein the abnormality diagnosing section displays a position of an abnormality and a message that informs a user of a countermeasure for a cause as a diagnosis result on the display section.

4. The moisture meter according to claim 2, characterized by comprising a display section, wherein the abnormality diagnosing section displays a position of an abnormality and a message that informs a user of a countermeasure for a cause as a diagnosis result on the display section.

5. A moisture meter characterized by comprising: a mass measuring section that measures a mass of a sample placed on a weighing pan; a heating chamber that is configured to be openable and closable, and in which the weighing pan is disposed; a heating section that is disposed in the heating chamber, and heats the sample; a control operation section that controls the heating section, performs heating until the mass of the sample changes to be below a predetermined threshold value, and calculates a moisture content of the sample based on a change in the mass of the sample before and after heating; a clock that measures a heating time; and a storage section, wherein the control operation section comprises: a standard substance measuring section that measures a moisture content of a standard substance for inspection as the sample, and measures the heating time; and an abnormality diagnosing section that compares a measured heating time with a predetermined time that is a set heating time and is stored in the storage section in advance, and diagnoses presence or absence of an abnormality of the heating section, wherein the measured heating time is a time from a start of heating to a time when the mass of the sample changes to be below the predetermined threshold value, and wherein the abnormality diagnosing section determines that the heating section has an abnormality when the measured heating time is longer than the predetermined time. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The abnormality diagnosing section determines that the heating section has an abnormality when the measured heating time is longer than the prescribed time, The heating section includes a heating mechanism, The heating chamber includes a glass cover for preventing the test sample from contacting the heating mechanism, The abnormality is contamination of the heating mechanism, contamination of the glass cover, or a failure of the heating mechanism.

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