JP2006134579A - Apparatus for detecting fault in threaded connecting part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for detecting faults in a threaded connecting part where a resistance load is connected to a feeder by threadedly engaging a male screw passed through an end of the resistance load used under a high temperature environment with a metal member of the power supply side. <P>SOLUTION: An arithmetic processing unit 6 measures a resistance value Ra of a load circuit A by a resistance measurement means 4 in a cut-off state where power supply equipment P is cut off from the feeder W by a power connection cutoff part 5; if the resistance value Ra is out of a normal range, the cut-off state is continued; and if within the normal range, in a connecting state where the power supply equipment P is connected to the feeder W by the power connection cutoff means 5, power is supplied to the load circuit A. While power is supplied to the load circuit A, a voltage V and a current I are measured by an amplitude measurement means 3 and a current measurement means 2, the resistance value R of the load circuit A is calculated based on them, and if the resistance value R is out of the normal range, it is determined to be abnormal. As a result, the fault of the threaded connecting part C can be detected and fault detection can be done before supply. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an abnormality detection device for a screw connection part, and more specifically, a male screw inserted into an end of a resistance load used in a high temperature environment of 500 ° C. or higher is screwed to a metal member on a power supply side. It is related with the abnormality detection apparatus of the screwing connection part which can detect generation | occurrence | production of the abnormality in the screwing connection part which connects a resistance load and a feeder.

2. Description of the Related Art Conventionally, there is known an apparatus that detects a voltage and current supplied to a heater, calculates a resistance value, and detects an abnormality of the heater based on whether the resistance value is within a specified range (for example, Patent Document 1). , See Patent Document 2).
Japanese Utility Model Publication No. 4-134063 Japanese Utility Model Publication No. 52-28763

In a film forming apparatus used in semiconductor manufacturing, for example, a MOCVD apparatus (organometallic compound chemical vapor deposition apparatus), since a semiconductor wafer is heated at a high temperature of 500 ° C. or higher and contamination generated from the heater is disliked, Ceramic-based heaters and silicon carbide heaters that generate less impurities are used.
Such a connection between the heater and the power supply line is generally performed by screwing a male screw inserted through the end of the heater into a metal member on the power supply side. Therefore, this connection portion is called a screw connection portion.

  By the way, the material which comprises a ceramic type | system | group heater, a silicon carbide heater, etc. tends to generate | occur | produce a crack and a chip. In addition, the same material and hardness are used for the male screw, but a high heat-resistant material that is vulnerable to impact is used, so cracking and chipping are likely to occur. Therefore, the screwing of the male screw must be fastened with a low torque (15 to 20 cN / m or less) so that cracking and chipping do not occur, and the frictional force for maintaining the screwed state is very weak. It is in.

  For this reason, if the threaded connection repeats thermal expansion and contraction due to heating and cooling, or if vibration is applied to the threaded connection, the threaded connection will loosen, resulting in incomplete electrical contact and contact resistance. May increase. And if power supply is continued to a heater in this state, the part where contact resistance increased will generate heat to high temperature, and it may be damaged by melting and fusing. This phenomenon appears even more strongly if the heater is housed in a vacuum vessel that is difficult to dissipate heat.

  In addition, when a high voltage is applied to the screw connection part or heater (for example, 50 V or more if the screw connection part or heater is accommodated in a vacuum vessel), glow discharge or arc discharge occurs in the vicinity thereof. There is. And the part which discharge generate | occur | produces locally high temperature may generate | occur | produce, and it may be damaged by fusion | melting or fusing.

  Furthermore, since the heater temperature control is generally performed by PID control (P is proportional, I is integral, and D is derivative), the maximum power is supplied to the heater when the deviation immediately after the start of power supply to the heater is large. However, if there is an abnormality in the screw connection part or the heater, the damage may be maximized. Therefore, it is necessary to detect an abnormality before starting to supply power to the heater.

However, the above-described conventional technique detects the abnormality of the heater itself and has a problem that it cannot detect even the abnormality of the screw connection part. In addition, there is a problem that abnormality cannot be detected before power is supplied to the heater.
Accordingly, an object of the present invention is to provide an abnormality detection device for a screw connection part that can detect an abnormality of a screw connection part and can detect an abnormality before power feeding.

In a first aspect, the present invention is configured by screwing a resistance load L used in a high temperature environment of 500 ° C. or higher and a male screw B inserted through an end of the resistance load L into a metal member N on the power supply side. Resistance measuring means 4 for measuring the resistance value of the load circuit A including the resistance load L and the screw connection C for connecting the feeder line W, and voltage detection for detecting the voltage V applied to the load circuit A Means 3, current detection means 2 for detecting the current I flowing through the load circuit A, power connection device P for supplying power to the load circuit A via the power supply line W, and power connection interruption for connecting / interrupting the power supply line W Means 5 and an arithmetic processing unit 6, and the arithmetic processing unit 6 is configured such that the resistance measuring means is in a cut-off state in which the power supply device P and the feeder line W are cut off by the power connection cut-off unit 5. 4 to measure the resistance value Ra of the load circuit A and If Ra is outside the normal range, the cut-off state is continued. If Ra is within the normal range, the power connection cut-off means 5 is connected to the power supply device P and the power supply line W to supply power to the load circuit A. The voltage V and current I are measured by the voltage measuring means 3 and the current measuring means 2 while power is being supplied to the load circuit, and the resistance value R of the load circuit A is calculated based on the measured values. If the resistance value R is outside the specified range, Provided is an abnormality detecting device 1 for a screw connection portion, characterized by determining an abnormality.
In the screw connection part abnormality detection device 1 according to the first aspect, only the load resistance L is measured in order to determine the abnormality by measuring the resistance values Ra and R of the load circuit A including the load resistance L and the screw connection part C. In addition, it is possible to detect an abnormality in the screw connection portion C. Further, since the resistance value Ra of the load circuit A is measured before power feeding to determine abnormality, abnormality detection can be performed before power feeding.
In addition, when the resistance value of the resistive load L that should originally be known is known,
It is possible to calculate the resistance value of the screw connection part C from the resistance value of the screw connection part C = Ra or the resistance value of the R-resistance load L.

In a second aspect, the present invention relates to the abnormality detecting device 1 for the screw connection part according to the first aspect, wherein the arithmetic processing unit 6 is configured to connect the screw connection part C or the load if the resistance value R is larger than a specified range. Provided is an abnormality detection device 1 for a threaded connection, wherein it is determined that the resistance L is abnormal, and if the resistance value R is smaller than a specified range, it is determined that there is an abnormality due to the occurrence of discharge.
When the screw connection portion is loosened, the electrical contact becomes incomplete and the contact resistance increases. On the other hand, when glow discharge or arc discharge occurs, the resistance value decreases due to a short circuit.
Therefore, in the screw connection portion abnormality detection device 1 according to the second aspect, if the resistance value R is larger than the specified range, it is determined that the screw connection portion C or the load resistance L is abnormal, and the resistance value R is less than the specified range. If it is small, it can be determined that there is an abnormality due to the occurrence of discharge.

In a third aspect, the present invention provides a light receiving means for receiving light emitted from the resistance load L or the screw connection part C in the screw connection part abnormality detection device 1 according to the first or second aspect. 20 is provided, and the arithmetic processing device 6 provides an abnormality detection device 1 for a screw connection portion, which is determined to be abnormal when light is received by the light receiving means 20.
When the resistance value of the resistance load L or the screw connection C increases and red heat is generated, red light is emitted. On the other hand, when a discharge occurs at the resistance load L or the screw connection C, discharge light is emitted.
Therefore, in the abnormality detecting device 1 for the screw connection portion according to the third aspect, the abnormality is detected by a method different from the change in the resistance value by receiving red light or discharge light.

In a fourth aspect, the present invention relates to the abnormality detecting device 1 for a screw connection part according to the third aspect, wherein the arithmetic processing device 6 is screwed based on a wavelength band of light received by the light receiving means 20. Provided is an abnormality detection device 1 for a screw connection part, characterized by determining whether the connection part C or load resistance L is abnormal due to red heat or discharge.
The red light and the discharge light, which indicate a high temperature state, have different wavelength bands.
Therefore, in the abnormality detecting device 1 of the screw connection portion according to the fourth aspect, it is determined whether the screw connection portion C or the load resistance L is abnormal due to red heat or abnormal discharge due to the wavelength band of the received light. . In addition, the wavelength band of the received light can be distinguished by providing the light receiving means 20 with a filter that matches the wavelength band of the red light and a filter that matches the wavelength band of the discharge light.

In a fifth aspect, the present invention relates to the abnormality detecting device for a screw connection portion according to any one of the first to fourth aspects, wherein the arithmetic processing unit 6 is operated at a temperature t of the load resistance L or a power feeding time. Accordingly, there is provided an abnormality detecting device 1 for a screw connection part, wherein the specified range is changed accordingly.
In the case where the resistance value of the resistance load L varies greatly with temperature, such as a silicon carbide heater, the specified range needs to be changed according to the temperature.
Accordingly, in the abnormality detection device 1 for the screw connection portion according to the fifth aspect, the specified range is changed according to the temperature t of the load resistance L. If the relationship between the power supply time and the temperature t of the load resistance L is substantially constant, the specified range may be changed according to the power supply time.

In a sixth aspect, the present invention relates to the abnormality detecting device for a screw connection part according to any one of the first to fifth aspects, wherein the arithmetic processing unit 6 is abnormal while supplying power to the load circuit A. When it is determined that the power connection device 5 and the power supply line W are shut off by the power connection cut-off means 5, the power supply is stopped and the abnormality detecting device 1 for the screw connection portion is provided.
In the abnormality detecting device 1 for the screw connection portion according to the sixth aspect, when it is determined that there is an abnormality, the power supply is stopped without waiting for an instruction from the operator or the host device H, so that safety can be improved.

  According to the abnormality detection device for a screw connection portion of the present invention, a resistance load is obtained by screwing a male screw inserted into an end portion of a resistance load used in a high temperature environment of 500 ° C. or more into a metal member on the power supply side. It is possible to detect the occurrence of an abnormality in the screw connection portion that connects the power supply line and the power supply line. Further, abnormality detection can be performed before power feeding.

  Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. Note that the present invention is not limited thereby.

FIG. 1 is a configuration diagram illustrating a heater temperature control device 100 including an abnormality detection device 1 for a screw connection portion according to a first embodiment.
The heater temperature control apparatus 100 measures the temperature of a resistance load L that is a heater for heating the semiconductor wafer, a screw connection C for connecting the resistance load L and the power supply line W, and the temperature of the resistance load L. A temperature sensor T, a vacuum load D containing a resistance load L, a screw connection C, and a temperature sensor T, and a vacuum exhaust device E for exhausting the vacuum container D to a pressure of about 10 Pa to 100 Pa, for example. The power supply device P that supplies power to the load circuit A including the resistance load L and the screw connection C via the feeder line W, and the temperature measured by the temperature sensor T is a desired heater temperature (for example, 600 ° C. to 800 ° C. Temperature controller Q for controlling the power supplied from the power supply device P so that the power supply device P is at a temperature, the abnormality detecting device 1 for the screw connection portion interposed in the middle of the power supply line W, the temperature controller Q and the screw Finger to the abnormality detection device 1 of the joint And a host device H such as a host computer that gives.

  The abnormality detecting device 1 for the screw connection portion includes a resistance measuring unit 4 for measuring a resistance value of the load circuit A, a voltage detecting unit 3 for detecting a voltage V applied to the load circuit A, and a load circuit A. A current detection unit 2 that detects a flowing current I, a power connection blocking unit 5 that connects / cuts off the power supply device P and the power supply line W, an arithmetic processing unit 6 such as a one-chip microcomputer, a resistance measurement unit 4 and a power supply line And a switch 7 for connecting / disconnecting W.

  By making the abnormality detection device 1 of the screw connection part as shown in FIG. 1, it becomes possible to easily incorporate it into an existing device.

As shown in FIG. 2, in the screw connection portion C, the male screw B inserted through the end portion of the resistance load L is screwed into the connection pipe N on the power supply side, thereby connecting the resistance load L and the feeder line W. Is going.
The resistance load L is a material constituting a ceramic heater, a silicon carbide heater, or the like, and is easily cracked or chipped.
The male screw B is the same material as the resistance load L or a high heat resistant material that is high in hardness but weak against impact, and is likely to be cracked or chipped.
Therefore, the screwing of the male screw B must be fastened with a low torque (15 to 20 cN / m or less) so that cracking and chipping do not occur, and the frictional force for maintaining the screwed state is very weak. Is in a state.

FIG. 3 is a flowchart showing the abnormality detection process of the screw connection portion by the arithmetic processing device 6. This process is started when an energization command is given from the host apparatus H to the arithmetic processing unit 6.
In step S1, the switch 7 is turned on in a state where the load circuit A and the power supply device P are disconnected by the power connection breaker 5, and the resistance value Ra of the load circuit A is measured.
In step S2, it is determined whether or not the resistance value Ra measured by the load circuit A is within the normal range. If the resistance value Ra is outside the normal range, the process proceeds to step S3, and if it is within the normal range, the process proceeds to step S4.

  In step S3, it is determined that the screw connection portion C and / or the resistance load L is abnormal, and the power connection breaker 5 maintains the state where the load circuit A and the power supply device P are cut off, and the power to the load circuit A is maintained. Do not supply. Then, the abnormality is reported to the host device H, and the process is terminated.

  In step S4, the switch 7 is turned off, the load circuit A and the power supply device P are connected by the power connection breaker 5, and power is supplied to the load circuit A. As a result, the resistance load L rises in temperature, but when the indicated value from the temperature controller Q changes for temperature adjustment, the voltage V output from the power supply device P changes and the current I flowing through the load circuit A changes. Also changes.

In step S5, the voltage V detected by the voltage detector 3 and the current I detected by the current detector 2 are read. Note that the number of readings of the voltage V and the current I may be one, but if the averaging is performed as a plurality of times, adverse effects such as noise can be suppressed. In this case, it is preferable that the reading cycle and number of times can be changed as necessary.
In step S6, if the current I is 0, the resistance value R cannot be calculated, and the process returns to step S5. If not, the resistance value R can be calculated, and the process proceeds to step S7. Note that the current I becomes zero when the temperature of the resistance load L measured by the temperature sensor T is higher than the desired heater temperature.
In step S7, the resistance value R of the resistive load L is calculated from R = V / I.

  In step S10, if the resistance value R is outside the specified range, the process proceeds to step S11, and if it is within the specified range, the process proceeds to step S22.

In step S11, the power connection breaker 5 interrupts the load circuit A and the power supply device P, and the power supply to the load circuit A is stopped.
In step S12, if the resistance value R is on the increase side from the specified range, the process proceeds to step S13, and if it is on the decrease side, the process proceeds to step S14.

  In step S13, it is determined that the screw connection part C and / or the resistance load L is abnormal, the fact is reported to the host device H, and the process is terminated. When there is no abnormality, the resistance value R is within the specified range as shown in FIG. 4, but when there is an abnormality in the screw connection C and / or the resistance load L, the resistance value R is within the specified range as shown in FIG. It is because it changes to the increase side.

  In step S14, it is determined that glow discharge or arc discharge has occurred at the screw connection portion C, the resistance load L, or the power supply introduction terminal of the vacuum vessel D, the fact is reported to the host device H, and the process is terminated. . When there is no abnormality, the resistance value R is within the specified range as shown in FIG. 4, but when the discharge occurs, the resistance value R changes from the specified range to the decreasing side as shown in FIG.

In step S22, it is checked whether a stop command has been given from the host device H. If not, the process returns to step S5, and if given, the process proceeds to step S23.
In step S <b> 23, the power connection breaker 5 interrupts the load circuit A and the power supply device P, and the power supply to the load circuit A is stopped. Then, the process ends.

According to the abnormality detection device 1 of the screw connection part of the first embodiment, the following effects can be obtained.
(1) It is possible to detect not only the load resistance L but also an abnormality in the screw connection C.
(2) Abnormality detection can be performed before power feeding.
(3) It is possible to distinguish between an abnormality in the screw connection C and / or the resistance load L and an abnormality in the occurrence of discharge.

FIG. 7 is a configuration diagram illustrating the heater temperature control device 100 including the abnormality detection device 1 for the screw connection portion according to the second embodiment.
The heater temperature control apparatus 100 measures the temperature of a resistance load L that is a heater for heating the semiconductor wafer, a screw connection C for connecting the resistance load L and the power supply line W, and the temperature of the resistance load L. Temperature sensor T, resistance load L, screw connection C and vacuum vessel D containing temperature sensor T, vacuum exhaust device E for exhausting from vacuum vessel D, and resistance load L and screw connection The power supply device P that supplies power to the load circuit A including the part C via the power supply line W and the power supply so that the temperature measured by the temperature sensor T becomes a desired heater temperature (for example, 600 ° C. to 800 ° C.). A temperature regulator Q for controlling the power supplied from the device P, an abnormality detection device 1 for the screw connection portion interposed in the middle of the power supply line W, and an abnormality detection device 1 for the temperature regulator Q and the screw connection portion. A host computer such as a host computer that gives commands to And a H.

  The abnormality detecting device 1 for the screw connection portion includes a resistance measuring unit 4 for measuring a resistance value of the load circuit A, a voltage detecting unit 3 for detecting a voltage V applied to the load circuit A, and a load circuit A. A current detection unit 2 that detects a flowing current I, a power connection blocking unit 5 that connects / cuts off the power supply device P and the power supply line W, an arithmetic processing unit 6 such as a one-chip microcomputer, a resistance measurement unit 4 and a power supply line A switch 7 for connecting / blocking W and a light receiving unit 20 for receiving light emitted from the resistance load L or the screw connection C through the glass window 19 of the vacuum vessel D are provided.

  The light receiving unit 20 has a filter that matches the wavelength band of the red light emitted by the red heat of the screw connection C or the load resistor L, and the wavelength band of the discharge light so that the wavelength band of the received light can be distinguished. And a combined filter.

  By forming the abnormality detecting device 1 of the screw connection portion as shown in FIG. 7, it can be easily incorporated into an existing device.

FIG. 8 is a flowchart showing abnormality detection processing of the screw connection portion by the arithmetic processing device 6. This process is started when an energization command is given from the host apparatus H to the arithmetic processing unit 6.
In step S1, the switch 7 is turned on in a state where the load circuit A and the power supply device P are disconnected by the power connection breaker 5, and the resistance value Ra of the load circuit A is measured.
In step S2, it is determined whether or not the resistance value Ra measured by the load circuit A is within the normal range. If the resistance value Ra is outside the normal range, the process proceeds to step S3, and if it is within the normal range, the process proceeds to step S4.

  In step S3, it is determined that the screw connection portion C and / or the resistance load L is abnormal, and the power connection breaker 5 maintains the state where the load circuit A and the power supply device P are cut off, and the power to the load circuit A is maintained. Do not supply. Then, the abnormality is reported to the host device H, and the process is terminated.

  In step S4, the switch 7 is turned off, the load circuit A and the power supply device P are connected by the power connection breaker 5, and power is supplied to the load circuit A. As a result, the resistance load L rises in temperature, but when the indicated value from the temperature controller Q changes for temperature adjustment, the voltage V output from the power supply device P changes and the current I flowing through the load circuit A changes. Also changes.

In step S5, the voltage V detected by the voltage detector 3 and the current I detected by the current detector 2 are read.
In step S6, if the current I is 0, the resistance value R cannot be calculated, and the process returns to step S5. If not, the resistance value R can be calculated, and the process proceeds to step S7.
In step S7, the resistance value R of the resistive load L is calculated from R = V / I.

In step S <b> 8, the temperature controller Q reads the temperature t of the resistive load L measured by the temperature sensor T from the temperature controller Q.
In step S9, a specified range corresponding to the temperature t is set. When the resistance load L is, for example, a silicon carbide heater, the resistance value R varies depending on the temperature t as shown in FIG. Therefore, it is necessary to change the specified range according to the temperature t. As shown in FIG. 10, if the relationship between the power supply time and the temperature t of the load resistance L is substantially constant, the specified range may be changed according to the power supply time.

  In step S10, if the resistance value R is outside the specified range, the process proceeds to step S11, and if it is within the specified range, the process proceeds to step S15.

In step S11, the power connection breaker 5 interrupts the load circuit A and the power supply device P, and the power supply to the load circuit A is stopped.
In step S12, if the resistance value R is on the increase side from the specified range, the process proceeds to step S13, and if it is on the decrease side, the process proceeds to step S14.

  In step S13, it is determined that the screw connection part C and / or the resistance load L is abnormal, the fact is reported to the host device H, and the process is terminated. When there is no abnormality, the resistance value R is within the specified range as shown in FIG. 4, but when there is an abnormality in the screw connection C and / or the resistance load L, the resistance value R is within the specified range as shown in FIG. It is because it changes to the increase side.

  In step S14, it is determined that glow discharge or arc discharge has occurred at the screw connection portion C, the resistance load L, or the power supply introduction terminal of the vacuum vessel D, the fact is reported to the host device H, and the process is terminated. . When there is no abnormality, the resistance value R is within the specified range as shown in FIG. 4, but when the discharge occurs, the resistance value R changes from the specified range to the decreasing side as shown in FIG.

In step S15, the light reception result of whether the red light is received from the light receiving unit 20 and whether the discharge light is received is read.
In step S16, if red light is received, the process proceeds to step S17, and if red light is not received, the process proceeds to step S19.

In step S <b> 17, the power connection breaker 5 interrupts the load circuit A and the power supply device P, and the power supply to the load circuit A is stopped.
In step S18, it is determined that the screw connection part C and / or the resistance load L is abnormal, the fact is reported to the host device H, and the process is terminated. This is because when the red light is received, it is determined that the screw connection C and / or the resistance load L is red hot.

  In step S19, if the discharge light is received, the process proceeds to step S20, and if the discharge light is not received, the process proceeds to step S22.

In step S <b> 20, the load circuit A and the power supply device P are disconnected by the power connection breaker 5, and the power supply to the load circuit A is stopped.
In step S21, it is determined that an abnormality has occurred in the discharge, the fact is reported to the host device H, and the process is terminated. This is because when the discharge light is received, it is determined that glow discharge or arc discharge is generated at the screw connection portion C, the resistance load L, or the power supply introduction terminal of the vacuum vessel D.

In step S22, it is checked whether a stop command has been given from the host device H. If not, the process returns to step S5, and if given, the process proceeds to step S23.
In step S <b> 23, the power connection breaker 5 interrupts the load circuit A and the power supply device P, and the power supply to the load circuit A is stopped. Then, the process ends.

According to the abnormality detection device 1 for the screw connection part of the second embodiment, the following effects can be obtained.
(1) It is possible to detect not only the load resistance L but also an abnormality in the screw connection C.
(2) Abnormality detection can be performed before power feeding.
(3) It is possible to distinguish between an abnormality in the screw connection C and / or the resistance load L and an abnormality in the occurrence of discharge.
(4) Apart from the change in the resistance value R of the load circuit A, an abnormality can be detected by light.

  A device corresponding to the power connection breaker 5 may be provided in the power supply device P.

  The resistance measurement unit 4 is omitted, a low voltage (for example, 5 V) that does not adversely affect the load circuit A is applied from the power supply device P to the load circuit A, the voltage V is measured using the voltage detection unit 3, and the current I is The resistance value Ra of the load circuit A before full-scale power feeding may be obtained by measurement using the detection unit 2 and Ra = V / I.

  The abnormality detection device for a screw connection part according to the present invention supplies a resistance load to a resistance load by screwing a male screw inserted into an end of a resistance load used in a high temperature environment of 500 ° C. or more into a metal member on the power supply side. It can be used to detect the occurrence of an abnormality in the threaded connection for connecting the electric wires.

It is a block diagram which shows the heater temperature control apparatus 100 containing the abnormality detection apparatus 1 of the screwing connection part which concerns on Example 1. FIG. It is sectional drawing which shows a screwing connection part. 3 is a flowchart illustrating abnormality detection processing of a screw connection portion according to Embodiment 1. It is a graph which shows the change of resistance value R when it is not abnormal. It is a graph which shows the change of the resistance value R when abnormality of the screwing connection part C and / or resistance load L generate | occur | produces. It is a graph which shows the change of the resistance value R when discharge generate | occur | produces. It is a block diagram which shows the heater temperature control apparatus 100 containing the abnormality detection apparatus 1 of the screwing connection part which concerns on Example 2. FIG. 7 is a flowchart illustrating abnormality detection processing of a screw connection portion according to Embodiment 2. It is a graph which shows the change of the resistance value R with temperature, and the change of a regulation range. It is a graph which shows the change of the temperature t by the electric power feeding time, the change of the resistance value R, and the change of the regulation range.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Abnormality detection apparatus of screw connection part 2 Current detection part 3 Voltage detection part 4 Resistance measurement part 5 Power connection interruption | blocking part 6 Arithmetic processing device 7 Switch 19 Glass window 20 Light-receiving part A Load circuit B Male screw C Screw connection part E Vacuum exhaust device H Host device N Connecting pipe P Power supply device Q Temperature controller L Resistance load T Temperature sensor W Feed line D Vacuum container

Claims (6)

The resistance load L and the feeder line W are connected by screwing the resistance load L used in a high temperature environment of 500 ° C. or more and the male screw B inserted through the end of the resistance load L into the metal member N on the power supply side. A resistance measuring means 4 for measuring the resistance value of the load circuit A including the threaded connection C to be performed; a voltage detecting means 3 for detecting the voltage V applied to the load circuit A; and a current flowing through the load circuit A A current detection means 2 for detecting I, a power supply device P for supplying power to the load circuit A via the power supply line W, a power connection cutoff means 5 for connecting / cutting the power supply line W, and an arithmetic processing device 6 The arithmetic processing unit 6 is configured so that the resistance measuring unit 4 determines the resistance value Ra of the load circuit A in the cut-off state in which the power supply device P and the power supply line W are cut off by the power connection cut-off unit 5. Measure and shut off if the resistance value Ra is outside the normal range If the state is within the normal range, the power connection blocking means 5 connects the power supply device P and the power supply line W to supply power to the load circuit A, while supplying power to the load circuit A. The voltage V and current I are measured by the voltage measuring means 3 and the current measuring means 2, and the resistance value R of the load circuit A is calculated based on the measured voltages V and I. If the resistance value R is outside the specified range, it is determined that there is an abnormality. An abnormality detecting device 1 for a screw connection part. The abnormality detection device 1 of the screw connection part according to claim 1, wherein the arithmetic processing unit 6 determines that the screw connection part C or the load resistance L is abnormal if the resistance value R is larger than a specified range, and the resistance value. An abnormality detecting device 1 for a screw connection portion, wherein if R is smaller than a specified range, it is determined that there is an abnormality due to occurrence of discharge. 3. The abnormality detecting device 1 of the screw connection part according to claim 1 or 2, further comprising a light receiving means 20 for receiving light emitted from the resistance load L or the screw connection part C, wherein the arithmetic processing unit 6 is provided. Is an abnormality detection device 1 for a screw connection portion, wherein when the light is received by the light receiving means 20, it is determined that there is an abnormality. 4. The abnormality detection device 1 of the screw connection part according to claim 3, wherein the arithmetic processing unit 6 is based on the red heat of the screw connection part C or the load resistance L based on the wavelength band of the light received by the light receiving means 20. An abnormality detecting device 1 for a screw connection portion, wherein it is determined whether the abnormality is an abnormality due to occurrence of discharge or not. 5. The abnormality detection device for a screw connection part according to claim 1, wherein the arithmetic processing unit 6 changes the specified range in accordance with a temperature t of the load resistance L or a power supply time. An abnormality detection device 1 for a screw connection portion as a feature. 6. The abnormality detecting device for a screw connection part according to claim 1, wherein when the arithmetic processing unit 6 determines that an abnormality occurs while supplying power to the load circuit A, the power connection is cut off. An abnormality detecting device 1 for a screw connection part, characterized in that the power supply device P and the power supply line W are cut off by means 5 and the power supply is stopped.

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