JP2009156500A - Furnace and reliability test method of thermocouple for control - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a furnace capable of easily judging deterioration of a thermocouple for control measuring an internal temperature of a furnace body to control a heat source, with high accuracy. <P>SOLUTION: This furnace includes: the furnace body 11 to which a heated object is charged; the heat source 12 for heating the inside of the furnace body 11; a thermocouple unit 20 provided with the thermocouple 21 for control measuring the internal temperature of the furnace body 11 and provided with a detachable thermocouple 23 for test; a temperature control portion 25 controlling the output of the heat source 12 according to a measurement value measured by the thermocouple 21 for control and adjusting the internal temperature of the furnace body 11; and an information processing terminal 29 comparing the measurement value measured by the thermocouple 21 for control with a reference measurement value measured by the thermocouple 23 for test, and determining whether the error of the thermocouple 21 for control is less than a prescribed value or not. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention evaluates the reliability of a furnace that can be used as, for example, a heating furnace that heats a raw material such as a Ni-base heat-resistant alloy used for aircraft materials, a heat treatment furnace that performs heat treatment, and a control thermocouple provided in the furnace. The present invention relates to a reliability test method for a control thermocouple.

In general, in a metal material such as a Ni-base heat-resistant alloy, the structure is controlled by heating and heat treatment so as to obtain desired characteristics.
The furnace used when performing such heating and heat treatment is a furnace body charged with a metal material, a heat source for heating the inside of the furnace body, a temperature measuring means for measuring the internal temperature of the furnace body, A temperature control unit that adjusts the output of the heat source in accordance with a measured value obtained by the temperature measuring means.

  Here, a thermocouple is usually used as a sensor unit of temperature measuring means for measuring the internal temperature of the furnace body. The material of the thermocouple is selected according to the operating temperature. However, since the thermocouple is always disposed inside the high-temperature furnace body, it deteriorates with time when used for a long time. When the thermocouple deteriorates, it becomes impossible to grasp the accurate temperature inside the furnace body, and heat treatment under a predetermined condition cannot be performed.

Therefore, in a furnace that heats and heat-treats a metal material used as an aircraft material, a standard called AMS2750 is provided as a furnace management. In this AMS 2750, it is required to perform a system accuracy test (SAT) for testing the reliability of a thermocouple used for temperature control of the furnace body.
In the system accuracy test, for example, a thermocouple unit disclosed in Patent Document 1 is used, and a test thermocouple connected to a calibrated meter is provided in the vicinity of the thermocouple used for temperature control. It is a test that inserts and reads both measured values at the same time, confirms that the difference is below the standard value, and reads the periodicity to confirm the deterioration state. Conventionally, the temperature measured by the control thermocouple and displayed on the temperature control unit and the temperature of the temperature indicator connected to the test thermocouple are simultaneously read and compared.
Japanese Patent Laid-Open No. 10-48061

By the way, in a furnace that heats and heats a metal material used as an aircraft material, a heat source may be divided into a plurality of zones in order to make the temperature distribution inside the furnace body uniform. Each of these zones is provided with a thermocouple. The system accuracy test is required to be performed for all of these thermocouples, and due to the high frequency, a great amount of labor is required to test the reliability of the thermocouple.
Also, when reading the temperature displayed on the temperature controller and the temperature indicator connected to the test thermocouple, it is inevitable that a time lag will occur when checking these measured values. The high reliability test could not be performed.

  The present invention has been made in view of the above-described circumstances, and it is possible to easily and accurately determine the deterioration of the control thermocouple that measures the internal temperature of the furnace body in order to control the heat source. An object of the present invention is to provide a reliable furnace and a reliability test method for the control thermocouple.

In order to solve this problem, the present invention proposes the following means.
The furnace according to the present invention is provided with a furnace body in which an object to be heated is charged, a heat source for heating the inside of the furnace body, a control thermocouple for measuring the internal temperature of the furnace body, and for testing. A thermocouple unit in which a thermocouple is detachably mounted, a temperature control unit that controls the output of the heat source according to the measurement value measured by the control thermocouple, and adjusts the internal temperature of the furnace body; Information processing for comparing the measured value measured by the control thermocouple with the reference measured value measured by the test thermocouple to determine whether the error of the control thermocouple is equal to or less than a predetermined value And a terminal.

  In the furnace with this configuration, the measured value by the control thermocouple that measures the internal temperature of the furnace body and the reference measured value by the test thermocouple that is detachably attached to the thermocouple unit are stored in the data aggregation device. Therefore, the operator can confirm the measured value and the reference measured value without a time lag only by attaching the test thermocouple to the thermocouple unit. In addition, since it includes an information processing terminal that compares the measurement value transmitted from the data aggregation device with a reference measurement value to determine whether the error of the control thermocouple is a predetermined value or less, The reliability test of the control thermocouple can be easily performed. That is, the deterioration state of the thermocouple can be monitored by periodically comparing the measured value with the reference measured value.

Here, an analog-to-digital converter that converts the reference measurement value measured by the test thermocouple into a digital signal, the information processing terminal includes the measurement error of the test thermocouple and the analog-to-digital converter Whether or not the error of the control thermocouple is equal to or less than a predetermined value by calculating the reference correction value by correcting the reference measurement value based on the conversion error in It is preferable to be configured to determine
In this case, the information processing terminal calculates the reference correction value by correcting the reference measurement value based on the measurement error of the test thermocouple and the conversion error of the analog-digital converter of the reference measurement value. It is possible to compare the near reference correction value and the measured value measured by the control thermocouple, and it is possible to perform a more accurate reliability test.

Further, the measured value measured by the control thermocouple is converted into control unit data which is a digital signal in the temperature control unit, and the output of the heat source is controlled by the control unit data, and the control unit It is preferable that data is transmitted to the information processing terminal.
In this case, since the control unit data (digital signal of the measurement value) used when actually controlling the heat source in the temperature control unit is transmitted to the information processing terminal, not only the measurement error of the control thermocouple but also the temperature control It is possible to perform a reliability test including a conversion error to a digital signal in the unit.

Further, the measurement value measured by the control thermocouple is transmitted to the temperature control unit and the temperature recorder, and to the information processing terminal, the control unit data converted into a digital signal by the temperature control unit, It is preferable that recording data converted into a digital signal by the temperature recorder is transmitted.
In this case, it is possible to perform a reliability test including not only the measurement error of the control thermocouple as described above but also the conversion error into the digital signal in the temperature control unit. Further, the controller data converted into a digital signal by the temperature controller, the recorder data converted into a digital signal by the temperature recorder, and a reference measurement value measured by a test thermocouple are compared. Thus, it is possible to determine whether the control thermocouple is out of order or whether there is a problem in the digital conversion in the temperature control unit or the temperature recorder.

Further, the measurement value and the reference measurement value may be converted into a digital signal by the same analog-digital converter and transmitted to the information processing terminal.
In this case, since the measured value and the reference measured value are converted into a digital signal by the same analog-digital converter, an error in the conversion to the digital signal is canceled, and the reliability of the control thermocouple is accurately improved. Judgment can be made.

And a data aggregating device for accumulating the measurement value measured by the control thermocouple and the reference measurement value measured by the test thermocouple, and the measurement value and the reference measurement value are collected by the data aggregation. It is preferable to be configured to transmit to the information processing terminal via a device.
In this case, even in a furnace equipped with a large number of control thermocouples, the measurement values by the control thermocouple and the reference measurement values by the test thermocouple are stored in the data aggregation device and transmitted to the information processing terminal. Therefore, the reliability test of the control thermocouple can be easily performed.

A reliability test method for a control thermocouple according to the present invention is a reliability test method for a control thermocouple in the above-described furnace, wherein a test thermocouple is mounted on the thermocouple unit, and a test thermocouple is mounted. And the measurement value measured by the control thermocouple provided in the thermocouple unit is transmitted to the information processing terminal, and the measurement value and the reference measurement are transmitted to the information processing terminal. It is characterized in that it is determined whether or not the error of the control thermocouple is equal to or less than a predetermined value by comparing with a value.
In the reliability test method for the control thermocouple having this configuration, it is possible to evaluate the reliability of the control thermocouple simply by inserting the test thermocouple into the thermocouple unit.

  According to the present invention, it is possible to easily and accurately determine deterioration of a control thermocouple that measures the internal temperature of a furnace body in order to control a heat source, and the control thermocouple. A reliability test method can be provided.

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a furnace according to a first embodiment of the present invention.
The furnace 10 according to the present embodiment is a heat treatment furnace used when heat-treating a metal material (heated object) such as a Ni-base heat-resistant alloy used as an aircraft material. A sea test is required.

  The furnace 10 includes a furnace body 11 into which a metal material is charged, an electric heater 12 as a heat source for heating the interior of the furnace body 11, and a thermoelectric for measuring the internal temperature of the furnace body 11. A pair unit 20 and a temperature control unit 25 that adjusts the output of the electric heater 12 according to the internal temperature of the furnace body 11 are provided. The electric heater 12 is connected to a power source 13 through a thyristor 14.

  In the present embodiment, in order to make the temperature distribution inside the furnace body 11 uniform, the interior of the furnace body 11 is divided into a plurality of zones, and an electric heater 12 is provided for each zone. Is provided with a plurality of electric heaters 12. And although the thermocouple unit 20 is inserted in each of the plurality of divided zones, only one thermocouple unit 20 is displayed in FIG.

  The thermocouple unit 20 is provided with a control thermocouple 21 for measuring the internal temperature of the furnace body 11. The control thermocouple 21 is fixed to a thermocouple unit 20 inserted into the furnace body 11 and is configured to constantly monitor the internal temperature of the furnace body 11.

The control thermocouple 21 is first connected to the temperature control unit 25. In the temperature control unit 25, the analog signal (measurement value) from the control thermocouple 21 is converted into a digital signal (measurement value) by the built-in control unit A / D converter 25A and transmitted to the adjustment unit 25B. The adjusting unit 25B calculates the difference between the transmitted digital signal (measured value) and the set temperature and transmits the current control signal to the thyristor 14. Thereby, the energization amount from the power supply 13 to the electric heater 12 is adjusted, and the output of the electric heater 12 is controlled.
Further, the measurement value (control unit data) of the control thermocouple 21 converted into a digital signal (measurement value) by the control unit A / D converter 25 </ b> A is transmitted to the data logger 28.

Further, the control thermocouple 21 is connected to a temperature recorder 26 for recording the internal temperature of the furnace body 11. In this temperature recorder 26, the analog signal (measured value) from the control thermocouple 21 is converted into a digital signal (measured value) by the built-in recorder A / D converter 26A and transmitted to the recording unit 26B. Are configured to be recorded.
Further, the measurement value (control unit data) of the control thermocouple 21 converted into a digital signal (measurement value) by the recorder A / D converter 26 </ b> A is transmitted to the data logger 28.
Thus, in this embodiment, the control thermocouple 21 is connected to the temperature control unit 25 and the temperature recorder 26.

  In this embodiment, a thermocouple 22 for overheating that is different from the control thermocouple 21 is fixed to the thermocouple unit 20. This overheating thermocouple 22 is connected to the aforementioned temperature recorder 26, and the analog signal from the overheating thermocouple 22 is converted into a digital signal by the built-in recorder A / D converter 26A, It is configured to be transmitted and recorded in the recording unit 26 </ b> B, and the internal temperature of the furnace body 11 is constantly monitored in the same manner as the control thermocouple 21.

The thermocouple unit 20 is detachably mounted with a test thermocouple 23 for testing the reliability of the control thermocouple 21. The test thermocouple 23 is attached to the thermocouple unit 20 only when the reliability of the control thermocouple 21 is tested. The test thermocouple 23 is calibrated at an industrial laboratory or the like.
The test thermocouple 23 is connected to a data logger 28 via a test A / D converter 27, and an analog signal (reference measurement value) from the test thermocouple 23 is output by the test A / D converter 27. A digital signal (reference measurement value) is converted and transmitted to the data logger 28.

The data logger 28 transmits the measured values by the control thermocouple as control unit data and recorder data, and also transmits the reference measured values by the test thermocouple 23, and these measured values (control unit data and records). Meter data) and reference measurement values are simultaneously stored as digital signals.
The measurement values (control unit data and recorder data) and reference measurement values accumulated in this way in the data logger 28 are transmitted to the information processing terminal 29.

In the information processing terminal 29, the measurement error of the test thermocouple 23 and the conversion error of the test A / D converter 27 are input in advance, and the reference measurement value measured by the test thermocouple 23 is the measurement error and Correction is performed based on the conversion error, and a correction reference value is calculated.
The information processing terminal 29 is configured to compare the correction reference value with the above-described measurement values (control unit data and recorder data) and determine whether the difference is equal to or less than the standard value.

  When performing the reliability test of the control thermocouple 21 in the furnace 10, first, the test thermocouple 23 is inserted into the thermocouple unit 20, and the vicinity of the control thermocouple 21 located in the furnace body 11 is inserted. Measure the temperature. As a result, the reference measurement value measured by the test thermocouple 23 is stored in the data logger 28 as a digital signal. At the same time, the measured value measured by the control thermocouple 21 is converted into a digital signal by the control unit A / D converter 25A of the temperature control unit 25 as control unit data. Recorder data converted into digital signals by the D converter 26A is stored in the data logger 28, respectively.

Measurement values (control unit data and recorder data) and reference measurement values accumulated in the data logger 28 are transmitted to the information processing terminal 29. The information processing terminal 29 first corrects the reference measurement value to calculate a correction reference value, and compares this correction reference value with the measurement value.
Here, if the control unit data and the recorder data coincide with each other and the difference between the control unit data and the recorder data (measured value) and the correction reference value is less than the standard value, the control thermocouple 21 is deteriorated. Not determined. On the other hand, if the control unit data and the recorder data match each other, and the difference between the control unit data and recorder data (measured value) and the correction reference value is equal to or greater than the standard value, the control thermocouple 21 has deteriorated. It will be judged.

If the control unit data and the recorder data do not match, either the control unit A / D converter 25A built in the temperature control unit 25 or the recorder A / D converter 26A built in the temperature recorder 26 It is judged that there is a problem.
Here, if the control unit data matches the correction reference value, it is determined that the control thermocouple 21 has not deteriorated and the recorder A / D converter 26A has failed. On the other hand, if the recorder data and the correction reference value match, it is determined that the control thermocouple 21 has not deteriorated and the control unit A / D converter 25A has failed.
Further, when the control unit data, the recorder data, and the correction reference value are different from each other, the control thermocouple 21 is deteriorated, and further, the controller A / D converter 25A or the recorder A / D converter is used. It is determined that any of 26A has a problem.

  In the furnace 10 having such a configuration, the measurement value by the control thermocouple 21 that measures the internal temperature of the furnace body 11 and the reference measurement by the test thermocouple 23 that is detachably attached to the thermocouple unit 20. Since the values are stored in the same data logger 28, the operator can check the measured value and the reference measured value without a time lag only by attaching the test thermocouple 23 to the thermocouple unit 20. .

  Further, it has a test A / D converter 27 for converting a reference measurement value measured by the test thermocouple 23 into a digital signal. In the information processing terminal 29, the measurement error of the test thermocouple 23 and the test Based on the conversion error in the A / D converter, the reference measurement value is corrected to calculate the reference correction value, and the reference correction value is compared with the measurement value of the control thermocouple 21 to thereby detect the error of the control thermocouple 21. Since it is configured to judge, it is possible to compare the reference correction value close to the true value with the measured value measured by the control thermocouple 21 and to perform a highly reliable reliability test. It becomes.

  In addition, the measurement value measured by the control thermocouple 21 is transmitted to the temperature control unit 25 and converted into a digital signal by the control unit A / D converter 25A built in the temperature control unit 25, and then the adjustment unit 25B and Since it is transmitted to the data logger 28, a digital signal (control unit data) of a measurement value used in the adjustment unit 25 </ b> B that transmits a current control signal to the thyristor 14 is accumulated in the data logger 28. It is possible to evaluate the reliability including not only the measurement error but also the conversion error to the digital signal in the temperature control unit 25.

  Further, the measurement value measured by the control thermocouple 21 is transmitted to the temperature control unit 25 and the temperature recorder 26, and the data logger 28 has the temperature control unit 21 as the measurement value of the control thermocouple 21. Control unit data converted into a digital signal by the control unit A / D converter 25A built in 25, and recorder data converted into a digital signal by the recorder A / D converter 26A built in the temperature recorder 26; Whether the control thermocouple 21 has failed as described above by comparing the reference correction value by the test thermocouple 23 with the control unit data and recorder data. Alternatively, it can be determined whether there is a problem in the conversion to the digital signal in the temperature adjustment unit 25B or the temperature recorder 26.

Next, a second embodiment of the present invention will be described. FIG. 2 shows a furnace according to the second embodiment of the present invention.
Similarly to the first embodiment, this furnace 60 is also used when heat-treating a metal material (heated object) such as a Ni-base heat-resistant alloy used as an aircraft material, and is based on the AMS 2750 standard. System accuracy test is required.

  The furnace 60 includes a furnace body 61 in which a metal material is charged, an electric heater 62 as a heat source for heating the inside of the furnace body 61, and a thermoelectric for measuring the internal temperature of the furnace body 61. A pair unit 70 and a temperature control unit 75 that adjusts the output of the electric heater 62 in accordance with the internal temperature of the furnace body 61 are provided. The electric heater 62 is connected to a power source 63 via a thyristor 64.

  In this embodiment, in order to make the temperature distribution inside the furnace body 61 uniform, the interior of the furnace body 61 is divided into a plurality of zones, and an electric heater 62 is disposed in each zone. A plurality of electric heaters 62 are provided. And although the thermocouple unit 70 is inserted in each of the divided zones, only one thermocouple unit 70 is shown in FIG.

  The thermocouple unit 70 is provided with a control thermocouple 71 for measuring the internal temperature of the furnace body 61. The control thermocouple 71 is fixed to a thermocouple unit 70 inserted in the furnace body 61, and constantly monitors the internal temperature of the furnace body 61.

  The control thermocouple 71 is first connected to the temperature controller 75. In the temperature control unit 75, the analog signal (measured value) from the control thermocouple 71 is converted into a digital signal (measured value) by the built-in control unit A / D converter 75A and transmitted to the adjusting unit 75B. The adjusting unit 75B calculates the difference between the transmitted digital signal (measured value) and the set temperature, and transmits the current control signal to the thyristor 64. Thereby, the energization amount from the power source 63 to the electric heater 62 is adjusted, and the output of the electric heater 62 is controlled.

  Further, the control thermocouple 71 is connected to a temperature recorder 76 for recording the internal temperature of the furnace body 61. In the temperature recorder 76, the analog signal (measured value) from the control thermocouple 71 is converted into a digital signal (measured value) by the built-in recorder A / D converter 76A and transmitted to the recording unit 76B. Are configured to be recorded.

The control thermocouple 71 is also connected to the data logger 78 via the A / D converter 77.
Thus, in the present embodiment, the control thermocouple 71 is connected to the temperature controller 75, the temperature recorder 76, and the data logger 78.

  In the present embodiment, an overheating thermocouple 72 different from the control thermocouple 71 is fixed to the thermocouple unit 70, and the furnace body 61 is always in the same manner as the control thermocouple 71. The internal temperature is monitored. The overheating thermocouple 72 is connected to the temperature recorder 76 described above, and the analog signal from the overheating thermocouple 72 is converted into a digital signal by the built-in recorder A / D converter 76A. The recording unit 76B is configured to be transmitted and recorded.

  The thermocouple unit 70 is detachably mounted with a test thermocouple 73 for testing the reliability of the control thermocouple 71. The test thermocouple 73 is attached to the thermocouple unit 70 only when the reliability of the control thermocouple 71 is tested. The test thermocouple 73 is calibrated at an industrial laboratory or the like.

The test thermocouple 73 is connected to a data logger 78 via an A / D converter 77, and an analog signal (reference measurement value) from the test thermocouple 73 is converted into a digital signal (reference value) by the A / D converter 77. Measurement value) and transmitted to the data logger 78.
In other words, in the present embodiment, the measurement value (analog signal) of the control thermocouple 71 and the reference measurement value (analog signal) of the test thermocouple 73 are transmitted to the same A / D converter 77, and each is a digital signal. It has been converted to.

  The measurement value and the reference measurement value accumulated in the data logger 78 are transmitted to the information processing terminal 79, and the information processing terminal 79 measures the reference measurement value measured by the test thermocouple 73 and the control thermocouple 71. The measured value is compared, and it is determined whether the error is below the standard value.

  In the furnace 60 having such a configuration, the measurement value measured by the control thermocouple 71 and the reference measurement value measured by the test thermocouple 73 are converted into a digital signal by the same A / D converter 77. Therefore, the error at the time of conversion into a digital signal is canceled, and the reliability of the control thermocouple 71 can be determined easily and accurately.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of the invention.
For example, although it has been described that an overheating thermocouple is provided in addition to the control thermocouple, the present invention is not limited to this, and the overheating thermocouple may not be provided.

Moreover, although it demonstrated as a furnace (heat treatment furnace) which heat-processes the Ni-base heat-resistant alloy for aircraft materials, it is not limited to this, The heating furnace for heating Ni-base heat-resistant alloy may be sufficient. Moreover, there is no restriction | limiting in particular also about the to-be-heated material inserted in the inside of a furnace body.
Furthermore, although it demonstrated as what provided the electric heater as a heat source, it is not limited to this, You may provide other heat sources, such as a gas burner.
In addition, although it has been described as having a data logger (data aggregation device), the present invention is not limited to this, and the measurement value and the reference measurement value may be directly transmitted to the information processing terminal. .

It is a schematic explanatory drawing which shows the furnace which is the 1st Embodiment of this invention. It is a schematic explanatory drawing which shows the furnace which is the 2nd Embodiment of this invention.

Explanation of symbols

10, 60 Furnace 11, 61 Furnace 12, 62 Electric heater (heat source)
20, 70 Thermocouple unit 21, 71 Control thermocouple 23, 73 Test thermocouple 25, 75 Temperature controller 26, 76 Temperature recorder 27 Test A / D converter (analog / digital converter)
28, 78 Data logger (data aggregation device)
29, 79 Information processing terminal 77 A / D converter (analog / digital converter)

Claims (7)

A furnace body to be charged with an object to be heated;
A heat source for heating the interior of the furnace body;
A control thermocouple for measuring the internal temperature of the furnace body is provided, and a thermocouple unit to which a test thermocouple is detachably attached,
A temperature control unit for controlling the output of the heat source according to the measurement value measured by the control thermocouple and adjusting the internal temperature of the furnace body;
Information processing for comparing the measured value measured by the control thermocouple with the reference measured value measured by the test thermocouple to determine whether the error of the control thermocouple is equal to or less than a predetermined value A terminal,
A furnace characterized by comprising: An analog-to-digital converter that converts the reference measurement value measured by the test thermocouple into a digital signal;
The information processing terminal calculates a reference correction value by correcting the reference measurement value based on a measurement error of the test thermocouple and a conversion error in the analog-digital converter, and the reference correction value and the measurement value The furnace according to claim 1, wherein it is determined whether or not an error of the control thermocouple is equal to or less than a predetermined value.   The measured value measured by the control thermocouple is converted into control unit data which is a digital signal in the temperature control unit, and the output of the heat source is controlled by the control unit data, and the control unit data is The furnace according to claim 1, wherein the furnace is transmitted to the information processing terminal. The measured value measured by the control thermocouple is transmitted to the temperature control unit and the temperature recorder,
4. The control unit data converted into a digital signal by the temperature control unit and the recorder data converted into a digital signal by the temperature recorder are transmitted to the information processing terminal. The furnace described in 1.   The furnace according to claim 1 or 2, wherein the measured value and the reference measured value are converted into a digital signal by the same analog-digital converter and transmitted to the information processing terminal.   A data aggregating device for accumulating the measured value measured by the control thermocouple and the reference measured value measured by the test thermocouple; the measured value and the reference measured value are stored in the data aggregating device; The furnace according to any one of claims 1 to 5, wherein the furnace is transmitted to the information processing terminal. A reliability test method for a control thermocouple in a furnace according to any one of claims 1 to 6,
The thermocouple unit is mounted with a test thermocouple, and a reference measurement value measured by the test thermocouple and a measurement value measured by the control thermocouple provided in the thermocouple unit are processed. To the terminal,
In the information processing terminal, the reliability of the control thermocouple is characterized by determining whether or not an error of the control thermocouple is equal to or less than a predetermined value by comparing the measurement value and the reference measurement value Test method.

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