JP2001133344A - Measuring method of gas pressure and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely measure the sealed gas pressure of a gas-sealed apparatus having a dispersion of electrode interval or a gas-sealed apparatus having a fluctuating electrode interval. SOLUTION: This measuring method of gas pressure comprises applying a high voltage between a pair of electrodes, generating a discharge to gain a discharge voltage, and calculating the gas pressure on the basis of this discharge voltage. In this method, the capacitance between the electrodes is gained, the electrode interval is calculated from the capacitance, and the gas pressure is calculated from the discharge voltage and the electrode interval.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas pressure measuring method and apparatus capable of measuring a gas pressure in a gas-filled device such as a gas-filled relay switch.

[0002]

2. Description of the Related Art Conventionally, a discharge is generated by applying a high voltage between a pair of electrodes, and based on the discharge voltage of the generated discharge, detection of gas pressure abnormality, measurement of gas pressure, or insulation diagnosis is performed. (For example, Japanese Patent Application Laid-Open No. 55-16 / 55)
0832, JP-A-3-37538, JP-A-7-151812).

[0003]

These conventional devices are:
Since it is a prerequisite that the electrode spacing is constant, when measuring the gas pressure of a device having a large number of electrodes (for example, a gas-filled switch), the electrode spacing caused by the electrode processing accuracy and assembly accuracy There is a problem that the gas pressure measurement accuracy is deteriorated due to the influence of the variation of the gas pressure.In particular, it is difficult to accurately measure the gas pressure of a gas-filled switch such as a gas-filled relay switch in which the electrode interval fluctuates. Have difficulty.

When the gas pressure of the gas-filled switch of the above-described example is below the set gas pressure range, it is difficult to achieve the initial purpose. Since there is a problem that the durability of the structure is deteriorated, in the inspection at the time of shipment from the factory, it is required to measure the gas pressure with high accuracy to determine whether or not the sealed gas pressure is within the set pressure range.

SUMMARY OF THE INVENTION It is an object of the present invention to be able to measure a charged gas pressure with a high degree of accuracy for a gas filling device having a variation in electrode spacing or a gas filling device having a variable electrode spacing.

[0006]

SUMMARY OF THE INVENTION The present invention is a gas pressure measurement for obtaining a discharge voltage by applying a high voltage between a pair of electrodes to generate a discharge, and calculating a gas pressure based on the discharge voltage. Then, the capacitance between the electrodes is obtained, the electrode interval is calculated from the capacitance, and the gas pressure is calculated from the discharge voltage and the electrode interval.

As described above, by calculating the electrode spacing and calculating the gas pressure from the electrode spacing and the discharge voltage, even if there is variation between the electrodes in the gas filling device, the electrode spacing can be reduced. Even if it fluctuates, the measurement is performed taking into account the electrode spacing, so that the measurement will not be erroneous in the actual condition between the electrodes,
A highly accurate gas pressure can be calculated. Further, the electrode interval can be easily calculated from the capacitance by obtaining the capacitance between the electrodes.

The above-described calculation of the electrode spacing can be performed by substituting into a previously calculated calculation formula. Alternatively, an electrode spacing table obtained in advance for each layer of the capacitance may be used.

Further, the above-described calculation of the gas pressure based on the discharge voltage and the electrode interval can also be calculated by substituting into the previously calculated calculation formula. Alternatively, a gas pressure table obtained in advance for each level of the discharge voltage may be used.

In a preferred embodiment of the present invention, the high voltage applied between the electrodes is converted into a high DC voltage to obtain a discharge starting voltage, or a constant high DC voltage is applied after a discharge occurs to stop the discharge. Maintain and obtain the sustaining voltage, or obtain both of these voltages, and from the obtained firing voltage and electrode spacing, or from the sustaining voltage and electrode spacing,
Alternatively, the gas pressure is calculated from the discharge starting voltage, the discharge maintaining voltage, and the electrode interval.

That is, the gas pressure can be calculated from either one of the discharge starting voltage and the sustaining voltage and the electrode interval. For example, a rising high voltage is applied to generate a discharge, and a discharge starting voltage is obtained. As a method of calculating the gas pressure from the discharge starting voltage and the electrode interval, a constant DC high voltage is applied to maintain the discharge to obtain a discharge maintaining voltage, and the gas pressure is obtained from the discharge maintaining voltage and the electrode interval. May be calculated.

The above-mentioned rising DC high voltage may be a constant rising, a multi-step shape, or an arbitrary rising waveform.
For example, when the discharge starting voltage can be predicted to be relatively high, the voltage may be rapidly increased to a value equal to or lower than the voltage value, and then a gradually increasing voltage may be applied.

The above-mentioned constant DC high voltage may be higher or lower than the discharge starting voltage as long as it is higher than the sustaining voltage. Further, it is not necessary to determine the predetermined voltage value, and the voltage value may be varied depending on the gas pressure of the gas filling device. The applied DC high voltage may be any of positive polarity, negative polarity, and both positive and negative polarities.

The above-described calculation of the gas pressure based on the discharge starting voltage, the discharge sustaining voltage, and the electrode interval can be performed by substituting into a previously obtained calculation formula. In addition, the calculation formula can be calculated directly from the values based on the discharge starting voltage, discharge sustaining voltage, and electrode spacing. It is also possible to adopt a method of correcting the gas pressure in the above. Instead of using the calculation formula, a method using a gas pressure table obtained in advance for each layer of the discharge starting voltage, the discharge sustaining voltage, and the electrode interval may be used.

The order of measuring the discharge starting voltage, the discharge sustaining voltage, and the electrode interval may be any order.

Further, the application and stop of the DC voltage to the electrode are repeated, and the discharge is repeatedly performed at least twice or more, and the discharge starting voltage value after the second time, or the average value thereof, or the discharge after the second time is performed. The value of the sustaining voltage or the average value thereof can be used as the value of the discharge starting voltage and the value of the sustaining voltage. In this case, the effect of contamination on the electrode surface is reduced by the conditioning effect on the electrode surface due to the first discharge, and a stable discharge is generated by stabilizing the electrode surface temperature and forming a discharge path between the electrodes. By measuring the gas pressure with the obtained discharge voltage data, the measurement accuracy is further improved.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. The drawings show a gas pressure measuring method and a device thereof in a gas-filled relay switch as an example of a gas-filled device. In FIG. Fixed terminals 12, 1 on the ceiling
2 and Kovar round rings 13 and 13 are attached to the bases of the fixed terminals 12 and 12, respectively.
The Kovar round rings 13 and 13 are joined and fixed in an airtight manner by brazing. And fixed terminal 1
The inner ends of 2, 2 form fixed contacts 14,14.

A movable contact 15 is opposed to the fixed contacts 14 and 14 inside the ceramic case 11 to form an open / close contact of a relay switch.
The movable contact 15 is used as a pair of electrodes of the gas pressure measuring device.

The above-mentioned movable contact 15 is inserted into the upper end of the operating shaft 16 and is movable in the vertical direction. The movable contact 15 is prevented from falling off by an E-ring 17 at the upper end, and a flat washer 18 and a spring fixed to the lower part are fixed. 19 urges the E-ring 17 toward the E-ring 17.

The lower side of the operating shaft 16 is provided with a sealing plate 20.
Through the through hole 21 and extends downward, a sliding portion 22 having a large diameter is formed in the extending portion, and a sealing ring 23 is inserted into the sliding portion 22. The sliding portion 22 is guided by the sealing ring 23, and the sliding portion 22 slides vertically.

The above-mentioned sealing plate 20 is made of ceramic case 1
1 is air-tightly fixed to the lower opening edge by brazing or laser welding via a Kovar angle ring 24;
The sealing ring 23 is also air-tightly fixed to the sealing plate 20 by brazing or laser welding.

A coil 25 is fitted around the sliding part 22 of the operating shaft 16 and the outer peripheral part of the sealing ring 23.
The sliding portion 22 of the operating shaft 16 slides due to the electromotive force generated by the coil 25, and the fixed contacts 14, 14 and the movable contact 1
5 is closed and opened. A cover 26 also serving as a yoke is fitted on the outer periphery of the coil 25, and the cover 26 is fixed to the sealing plate 20 by brazing or laser welding.

The gas-filled relay switch 10 formed as described above has a ceramic case 11 and a fixed terminal 1.
4. An airtight chamber 27 is formed by the Kovar round ring 13, the Kovar angle ring 24, the sealing plate 20, and the sealing ring 23. In this airtight chamber 27, a mixed gas of hydrogen gas and nitrogen gas is applied at a pressure of 0.2 MPa. +0.05 MPa to -0.0
It is sealed in the range of MPa.

An electrode is required to measure the gas pressure of the sealed gas, but this electrode does not form a dedicated electrode, but is connected to one fixed contact 14 and one movable contact 15.
Used as a pair of electrodes.

The gas-filled relay switch 10 formed as described above has a structure in which the movable contact 15 is displaced or tilted due to the difference between the hole diameter of the movable contact 15 and the shaft diameter of the operating shaft 16. Therefore, the electrode gap CG between the fixed contact 14 and the movable contact 15 fluctuates.

The electrode spacing CG changes for each product depending on the processing accuracy and assembly accuracy of each component constituting the mounting structure on the fixed contact 14 side and the mounting structure on the movable contact 15 side. Therefore, these electrode gaps CG
Are different, when a discharge is generated between these electrodes,
Since the discharge voltages are different from each other, accurate measurement is impossible even if the gas pressure is measured using only the discharge voltage data.

As one embodiment of the present invention, a gas pressure measuring device 30 shown in FIG. 1 includes a capacitance measuring device 31 for measuring the above-mentioned electrode interval CG and a DC voltage for measuring a discharge voltage V of the electrode. High voltage power supply 32 and high voltage probe 33
And a measurement control personal computer (comprised of a personal computer) 34 for measuring and controlling these and calculating the gas pressure.

The capacitance measuring device 31 measures the capacitance between the electrodes formed by the fixed contact 14 and the movable contact 15,
From the measured values, the measurement control personal computer 34 calculates the electrode interval.

The above-described capacitance measuring device 31 is, for example,
Composed of LCR meter, 4-terminal pair structure test lead 35
Is connected to the fixed terminal 14 side and the cover 26 side of the gas-filled relay switch 10, and the capacitance between the electrodes formed by the fixed contact 14 and the movable contact 15 is measured and obtained. The measurement conditions are a parallel equivalent circuit (Cp-D), a frequency of 1 MHz, and an applied voltage of 5 V. The four-terminal pair measurement method is not used to minimize the influence of stray capacitance.

The above-described measured value of the capacitance is input to and acquired by the measurement control personal computer 34, and the obtained value is substituted into a calculation formula (Equation 1) for the electrode spacing to calculate the electrode spacing CG.

Electrode spacing [mm] = a × capacitance ＾ ^b [pF] (Equation 1) This Equation 1 is obtained by calculating the electrostatic capacity obtained in advance and the distance between the fixed contact 14 and the movable contact 15. This is a mathematical expression of the relationship, where a and b are constants.

FIG. 2 shows an approximate curve of the capacitance and the electrode interval. The plot in FIG.
G, dimensions of fixed contact 14, surface roughness, and movable contact 1
5 shows the result of acquiring the capacitance by changing the dimensions, surface roughness, displacement, inclination, and gas pressure, and formulates the result as Expression 1.

In FIG. 1, a DC high voltage power supply 32 for measuring a discharge voltage V of an electrode is controlled by a measurement control personal computer 34, and an arbitrary DC high voltage waveform is converted into a current limiting resistor 36,
The voltage is applied to the protection resistor 37 and the gas-filled relay switch 10.

The applied DC voltage is, in this example,
The maximum is 20 kV and 5 mA. Further, the connection to the gas-filled relay switch 10 is connected to one of the fixed terminals 14 and the cover 26 so that the fixed contacts 14 and the movable contacts 1 are connected.
The discharge voltage V between the electrodes formed in step 5 is measured and obtained.

The high-voltage waveform applied to the gas-filled relay switch 10 is divided by the high-voltage probe 33 and measured by the measurement control personal computer 34 as a discharge voltage waveform. Earth 3
Reference numeral 8 is provided as a ground for the high voltage circuit and as an electric shock accident prevention.

More specifically, a fixed contact 14 is provided between a fixed contact 14 and a movable contact 15 which are a pair of electrodes,
With the movable contact 15 as the ground, a DC high voltage that rises constantly from the DC high-voltage power supply 32 is applied to generate a discharge, the discharge voltage is divided by the high-voltage probe 33, and the measurement control personal computer 34 obtains a discharge voltage waveform as a discharge voltage waveform.

As shown in FIG. 3, the occurrence of discharge is detected by detecting the fall of the above-described discharge voltage waveform, and the peak value is set as the discharge start voltage Vs. After the occurrence of the discharge, the discharge is maintained by setting the applied DC high voltage to a constant voltage, a discharge maintenance voltage waveform is obtained, and the average value is used as the discharge maintenance voltage Vk.
And After a certain period of time has elapsed from the start of the application of the DC high voltage, the application of the voltage is stopped. The constant DC high voltage value was a voltage value obtained by adding a constant value to the discharge starting voltage.

Gas pressure P of gas-filled relay switch 10
Can be calculated by substituting the above-described discharge starting voltage Vs, discharge sustaining voltage Vk, and voltage interval CG into a previously calculated calculation formula (Formula 2).

Gas pressure P [MPa] = c × Vs [V] + d × Vk [V] + e × CG [pF] + f (Equation 2) c, d, e, and f are constants, respectively. .

FIG. 4 shows the relationship between the gas pressure P calculated by the above equation 2, the discharge starting voltage Vs, and the discharge sustaining voltage Vk. In FIG. 4, the plots show the electrode spacing CG, the size of the fixed contact 14, the surface roughness, and the size of the movable contact 15,
The graph shows the results of acquiring the discharge start voltage Vs and the discharge sustaining voltage Vk by changing the surface roughness, the displacement, the inclination, and the gas pressure. Further, the straight line in FIG. 4 shows the relationship between the gas pressure, the discharge starting voltage Vs, and the discharge sustaining voltage Vk when the inter-electrode CG is at the center value.

The gas pressure measuring device 3 configured as described above
The measurement of the gas pressure P of the gas sealed in the gas-filled relay switch 10 will be described with reference to the flowchart of FIG.

First, the gas-filled relay switch 10 to be measured is connected to the capacitance measuring device 31 to obtain the capacitance Cp between the fixed contact 14 and the movable contact 15 constituting the electrodes ( Step n1).

The capacitance Cp obtained by the processing of the measurement control personal computer 34 is substituted into a calculation formula (formula 1), and the electrode interval CG is calculated.
Is calculated and obtained (step n2).

Next, the gas-filled relay switch 10 from which the acquisition of the electrode interval CG has been completed is detached from the capacitance measuring device 31, and then connected to the DC high-voltage power supply 32 to acquire the discharge voltage. A rising DC high voltage is applied between the fixed contact 14 and the movable contact 15 to generate a discharge.

When the voltage is applied in this manner, a discharge is generated at a discharge starting voltage Vs corresponding to the gas pressure P × electrode interval CG according to Paschen's law as shown in FIG.

The measurement control personal computer 34 is a high-voltage probe 33
Is detected from the discharge voltage waveform input from the controller to obtain the value of the discharge start voltage Vs (step n).
3).

After the occurrence of the discharge, the measurement control personal computer 34 controls the DC high-voltage power supply 32 so that a constant DC high voltage is applied to the electrodes to maintain the discharge, and is input from the high-voltage probe 33. From the discharge voltage waveform, the discharge sustaining voltage Vk
Is obtained (step n4). Thereafter, the application of the DC high voltage is stopped. Since the values of the electrode interval CG, the discharge starting voltage Vs, and the discharge sustaining voltage Vk have been acquired in the measurement control personal computer 34, the gas pressure P is calculated from these values. In this example, the reference electrode interval is set, and the reference electrode interval, the discharge start voltage Vs, and the discharge sustaining voltage Vk are set.
Then, the reference gas pressure Ptmp is calculated by substituting Ptmp = c × Vs + d × Vk + f into a part of the calculation formula (Formula 2) (step n5).

Next, the gas pressure P corrected by the obtained actual electrode interval CG is calculated by the equation P = Ptmp + e × CG (step n6).

FIG. 7 shows the relationship between the measurement accuracy of the gas pressure P thus measured, the variation in the electrode spacing CG, and the presence or absence of the electrode spacing correction. As is clear from FIG. 7, when the correction is not performed using the electrode interval CG, the equation (equation 2) for calculating the gas pressure P is an equation obtained by substituting the center value into the electrode interval CG. Therefore, the measurement error of the gas pressure P increases as the electrode interval CG deviates from the center value. On the other hand, when the electrode interval CG of the measurement target is acquired and a correction term is added to the calculation formula of the gas pressure P based on the measured value, the measurement accuracy of the gas pressure P improves, and even when the electrode interval fluctuates, The gas pressure P can be accurately measured.

In the above-described measurement example, first, steps n1,
After acquiring the electrode interval CG at n2, steps n3 and n
4, the discharge voltages Vs and Vk are acquired, but these acquisitions may be reversed.

In the above measurement example, the application of the DC high voltage is described as being performed once, but as another measurement example, the application and the stop of the DC high voltage to the electrode are performed at least twice. It is possible to measure the gas pressure P by repeating the above-described discharge and obtaining the average value of the second and subsequent discharge start voltages Vs and the average value of the discharge sustaining voltage Vk and substituting them into the calculation formula (Formula 2). it can.

FIG. 8 shows the relationship between the discharge starting voltage obtained by generating five repetitive discharges and the number of repetitive discharges. 1
Since the discharge starting voltage Vs is the discharge from the non-discharge state and is affected by contamination of the electrode surface due to the combination, the obtained value greatly varies.

However, since the second and subsequent discharges are repetitive discharges at regular intervals, stabilization of the electrode surface and formation of a discharge path between the electrodes occur. Since the influence of surface contamination is reduced, the variation in the discharge starting voltage is reduced, and the voltage is stabilized. Therefore, the value at any one of the second and subsequent times, or the average value thereof, is calculated as the discharge starting voltage Vs
When used as, the measurement accuracy of the gas pressure P is further improved.

Further, as for the discharge sustaining voltage Vk, similarly to the case of the above-mentioned discharge starting voltage Vs, the obtained value for the second and subsequent times is stable. Alternatively, these average values may be used as the acquired values. However, since the effect is smaller than the case of the discharge starting voltage Vs, the average value may be an average value including the first time.

In correspondence between the configuration of the present invention and the above-described embodiment, the electrode of the present invention is the same as the fixed contact 14 of the embodiment,
The high voltage application means corresponds to the DC high voltage power supply 32, and the discharge voltage acquisition means similarly corresponds to the movable contact 15.
Although it corresponds to the high-voltage probe 33, the capacitance acquisition unit corresponds to the capacitance measurement device 31, and the calculation unit corresponds to the measurement control personal computer 34, the present invention is limited to only the configuration of the above-described embodiment. Instead, the invention can be applied in accordance with the technical concept described in the claims.

[0056]

According to the present invention, even if the distance between the electrodes of a device in which gas is sealed varies depending on the processing accuracy and the assembly accuracy, the distance between the electrodes varies like a switch. Also, the gas pressure can be measured corresponding to the interval between the individual electrodes of the gas filling device, and the filled gas pressure can be measured with high accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a gas pressure measuring device.

FIG. 2 is a diagram showing the relationship between capacitance and electrode spacing.

FIG. 3 is a diagram showing an example of a measured waveform of a discharge voltage.

FIG. 4 is a diagram showing a relationship between a discharge voltage and a gas pressure.

FIG. 5 is a flowchart of a gas pressure measurement process.

FIG. 6 is a diagram showing Paschen's law.

FIG. 7 is a diagram showing the relationship between electrode gap variation and gas pressure measurement accuracy.

FIG. 8 is a diagram showing a relationship between the number of repeated discharges and a discharge starting voltage.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 gas relay switch 14 fixed contact 15 movable contact 30 gas pressure measuring device 31 capacitance measuring device 32 DC high voltage power supply 33 high voltage probe 34 measurement control personal computer

Continued on the front page F term (reference) 2F055 AA14 BB20 CC59 DD20 EE40 FF11 FF43 GG31 2F063 AA23 BA30 BC05 CA40 CB12 CC07 DA21 HA00 LA16 PA03 PA04

Claims (8)

[Claims] 1. A gas pressure measuring method comprising: applying a high voltage between a pair of electrodes to generate a discharge to obtain a discharge voltage; and calculating a gas pressure based on the discharge voltage. A gas pressure measuring method for acquiring a capacitance, calculating an electrode interval from the capacitance, and calculating a gas pressure from the discharge voltage and the electrode interval. 2. A discharge starting voltage is obtained by increasing a high voltage applied between the electrodes to a DC high voltage that rises, and / or after a discharge occurs, a constant DC high voltage is applied to maintain a discharge to maintain a discharge maintaining voltage. 2. The gas pressure measuring method according to claim 1, wherein the gas pressure is calculated from the acquired and obtained discharge starting voltage and / or discharge sustaining voltage and the electrode interval. 3. The gas pressure measurement method according to claim 1, wherein the discharge voltage is a second or subsequent discharge voltage obtained by repeatedly generating a discharge at least twice or an average value thereof. 4. The discharge starting voltage and / or the sustaining voltage for the second and subsequent times obtained by generating at least two or more discharges, or an average thereof. 2. The gas pressure measurement method according to 2. 5. A pair of electrodes spaced apart, a high voltage applying means for applying a high voltage between the electrodes, and a discharge voltage for applying a high voltage to the electrodes to obtain a discharge voltage when a discharge occurs. A gas pressure measuring device comprising: an acquiring unit, which calculates a gas pressure based on the acquired discharge voltage, wherein the capacitance acquiring unit acquires the capacitance between the electrodes, and A gas pressure measuring device comprising: a calculating means for calculating an interval between the electrodes and calculating a gas pressure from the electrode interval and the discharge voltage. 6. The method according to claim 6, wherein the high voltage applying means sets the applied high voltage to a rising DC high voltage and / or a constant DC high voltage after a discharge has occurred, and sets the discharge voltage acquiring means to the rising DC high voltage. Setting the discharge start voltage for discharging by application or / and obtaining the discharge sustaining voltage when the discharge is maintained by applying a constant DC high voltage after the occurrence of the discharge, and setting the calculation means to the obtained discharge start voltage or / 6. The gas pressure measuring device according to claim 5, wherein the gas pressure is calculated from the discharge maintaining voltage and the electrode interval. 7. A gas pressure measuring apparatus according to claim 5, wherein said calculating means is set so as to calculate based on a second or subsequent discharge voltage obtained by repeatedly generating a discharge at least twice or an average value thereof. . 8. The calculation means is set so as to calculate based on a discharge starting voltage and / or a discharge sustaining voltage and / or an average value of the second and subsequent discharges obtained by generating at least two or more discharges. 6. The gas pressure measuring device according to 6.