JP6133584B2 - Leak detector and Freon gas leakage measurement method - Google Patents

Description

  The present invention relates to a leak detector for detecting leakage of chlorofluorocarbon and a method for measuring the leakage of chlorofluorocarbon.

Freon gas (refrigerant fluorocarbon) used in refrigeration and air conditioning machines such as air conditioners has been developed and put into practical use in connection with environmental problems such as global warming.
At present, chlorofluorocarbons are used in a variety of new and old products, from common products to recent products in the field of refrigeration and air-conditioning machinery, and in these products, chlorofluorocarbon gas is always maintained in a state where a certain amount is filled. Is needed.

In general, “CFC leakage” is inspected at the time of product manufacture, maintenance inspection, repair, and the like. As a device for inspecting leaks, various leak detectors such as a handy type simple detector used in the field and a test / measurement device capable of quantitative measurement used in manufacturing inspection are used.
Conventionally, there is a leak detector that detects the amount of gas leak from the output of a sensor touching a sample gas (Patent Document 1). The leak detector disclosed in Patent Document 1 can also detect chlorofluorocarbon gas.

Further, as a commercially available leak detector, there is a leak detector that has a gas analysis function and corrects the output of a sensor for the gas after the gas type is determined in advance by a device (conventional example 1).
There is also a leak detector that simply detects the amount of leak output (conventional example 2). In this leak detector, the measurer prepares a correction coefficient table for the gas type, and obtains the final value by multiplying the output by the coefficient determined for the inspection gas by a separate computer.
Furthermore, there is a leak detector that stores an output conversion table for a gas type in a device and uses a value automatically corrected for the gas for a simple output by designating the gas type in the device in advance at the time of inspection (conventional technology). Example 3). In Conventional Example 3, a leak detector using this principle is often used in full-scale inspection equipment used in a factory.
There is a leak detector that uses a non-dispersive infrared (NDIR) sensor, analyzes a pattern of an infrared absorption frequency spectrum by a gas type, estimates a gas type, and corrects the gas (conventional example 4).

JP 2009-276309 A

In the leak detector shown in Patent Document 1, it is not assumed that the amount of leak is detected according to the gas type of Freon gas.
The leak detector of Conventional Example 1 has a function of determining the gas type in advance by the device, so that the device configuration itself is complicated. As a result, the leak detector is large, expensive, and cannot be applied to a handy type with a simple structure.
In Conventional Example 2, since the measurer must prepare a correction coefficient table for the gas type and obtain the correction value by manual calculation, the leak amount detection work becomes complicated.
In Conventional Example 3, since the output conversion table for the gas type must be stored in the device, the gas type cannot be easily added. In addition, the operating conditions such as the sensor operating point and the amplifier gain must be changed according to the number of gas types to be detected. However, setting many operating conditions in advance increases the scale of the control circuit unit. The structure of the leak detector becomes large because the range of usable voltage must be widened.

In addition, the following contents are problems to commercialize Conventional Example 3. Problems in commercializing Conventional Example 3 will be described based on the graph of FIG.
FIG. 8 illustrates the relationship between the density and the amplifier output voltage. The density is within the full scale (FS) setting range at the leak rate (3 gr / Year). Within this set range, the concentration of gas B at the saturation point F is PX, the concentration of gas A at the saturation point F is PY, and the concentration of gas C at the saturation point F is PZ. In addition, the sensitivity difference of gas B, gas A, and gas C shall be 1: 1.2: 1.8. In a region W area where the concentration of gas C is equal to or lower than the concentration PZ at the saturation point F, if a vertical line is made at an arbitrary concentration PW, the amplifier output voltages VA, VB, VC are between the intersections of the gas A, gas B, gas C and the horizontal axis. The result obtained by dividing this by the full scale (FS) is used as each table data, and the density is obtained using these table data.

Here, in the case where sensitivity correction is not performed for each gas, measurement of all gases is inaccurate in the region PV larger than the concentration PX of the gas B. The measurement of the gas A and the gas C is inaccurate between the regions PY-PX larger than the concentration PY at the saturation point F of the gas A and smaller than the concentration PX. Furthermore, even in the region PZ-PY , there is a gas that exceeds the full scale (FS), and measurement cannot be performed correctly.
When the density full scale (FS) is set to the region PV, measurement and recording cannot be performed correctly for all gases. When the concentration full scale (FS) is set to the point PX, the gas B can be measured and recorded correctly, but the gas A cannot be measured and recorded correctly, and the gas C cannot be measured and recorded correctly. Furthermore, when the concentration full scale (FS) is set to the point PY, the gas A can be measured and recorded correctly, but the gas B has the correct measured value but the concentration exceeding the point PY needs to be limited by exception processing. Thus, inconvenience occurs in recording. For example, if the sensitivity range is “H” and the full scale (FS) is 3 gr / Year, it will be displayed up to 6 gr / Year, and the gas C cannot be measured and recorded correctly. Further, when the operating point is changed and the full scale (FS) of the concentration is moved to the point PZ or the point PZ within the W region, the result output is performed in the order of gas B, gas A, and gas C as the distance from the point PZ increases. Since the decrease in resolution becomes large, the operating point is preferably set near the point PZ. The gas C can be measured and recorded correctly, but the gas A has the correct measured value, but the concentration exceeding the point PZ needs to be limited by exception processing, resulting in inconvenience in recording. Although the measured value of gas B is correct, the concentration exceeding the point PZ needs to be limited by exception processing, which causes inconvenience in recording.

As described above, when the conventional example 3 is commercialized, the output display value can be made uniform for each gas, but the resolution is different, and the deviation of the amplifier output is large, resulting in inconvenience in recording.
In Conventional Example 4, even if it is possible to determine a gas type having a characteristic pattern, it is difficult to distinguish several tens of types. Moreover, new chlorofluorocarbons are being developed one after another, but the types of gases that can be detected by practical equipment are limited.

  An object of the present invention is to provide a small but highly functional leak detector and a method for measuring the amount of flon gas leak.

Sensors do not have the same sensitivity to gas species. When full scale sensitivity (FS sensitivity) at the same concentration or leak rate is “10”, a reaction output of “10” is obtained for a certain gas A, but “6” is applied to a gas B different from the gas A. There may be only reaction output. Therefore, if the measurement result is simply output only from the sensor output, it will be different from the actual value, which is inconvenient.
Therefore, in the present invention, the purpose is to obtain a more correct result by controlling the operation of the sensor and processing the obtained data in order to correct the difference in the magnitude of the sensor output depending on the gas type. In particular, it has the following configuration that can be applied to a portable inexpensive device without incurring costs.

Specifically, the leak detector of the present invention includes a Freon gas concentration detection sensor that detects the concentration of Freon gas, and an apparatus main body that measures the concentration of Freon gas based on an output signal from the Freon gas concentration detection sensor. The main body amplifies the signal output from the CFC gas concentration detection sensor, a gas type setting unit for setting a predetermined gas type among a plurality of CFC gas types, and the CFC gas concentration detection for each gas type A drive condition storage unit that stores a drive condition of the sensor, a gas type correction value storage unit that stores a correction value that eliminates the deviation of the gas type, and an output voltage output from the amplifier in accordance with the predetermined gas type is saturated storage means having a FS data storage unit that stores FS correction data of the full scale density in a state, ejection stored in the drive condition storage unit The power supplied to the chlorofluorocarbon gas concentration detection sensor is controlled so as to limit the output region of the output signal from the chlorofluorocarbon gas concentration detection sensor based on the driving condition of the predetermined gas type set by the gas type setting unit among the conditions. A power control unit; raw data output from the Freon gas concentration detection sensor through the amplifier for each gas type in the output region controlled by the power control unit; and a correction value stored in the gas type correction value storage unit; Based on the gas type correction calculation unit for correcting the raw data, and the correction value corrected by the gas type correction calculation unit and the FS correction data stored in the FS data storage unit according to the predetermined gas type Calculation means having a final output value calculation unit for calculating the final output value, and display means for displaying the final output value calculated by the calculation means. It is characterized in.

The method for measuring the amount of leakage of chlorofluorocarbon gas of the present invention is the method for measuring the amount of leakage of chlorofluorocarbon gas , wherein the output signal from the chlorofluorocarbon gas concentration detection sensor is amplified by an amplifier and the amount of leakage of chlorofluorocarbon gas is measured based on the output from the amplifier. The driving condition storage unit stores the driving condition of the chlorofluorocarbon gas concentration detection sensor every time , and the gas type correction value storage unit stores the correction value for eliminating the deviation for each gas type, and the amplifier according to the predetermined gas type The FS data storage unit stores FS correction data relating to the full-scale concentration at which the output voltage output from the saturation state is saturated, and the driving condition of a predetermined gas type set among the driving conditions stored in the driving condition storage unit The power control unit supplies the CFC gas concentration detection sensor with a power control unit so as to limit an output region of the output signal from the CFC gas concentration detection sensor. Controls word, a correction value stored in said from said chlorofluorocarbon gas density detection sensor for each of the gas species in controlled output region power control unit and the raw data output through the amplifier gas species correction value storage unit The gas type correction calculation unit performs a calculation for correcting the raw data based on the correction value, and the predetermined gas is calculated from the correction value corrected by the gas type correction calculation unit and the FS correction data stored in the FS data storage unit. The final output value calculation unit calculates a final output value corresponding to the seed, and the display unit displays the final output value calculated by the calculation unit.

In the present invention having the above configuration, first, the gas type to be measured is set, and the driving conditions of the chlorofluorocarbon gas concentration detection sensor corresponding to the set gas type are loaded from the driving condition storage unit. Then, the power control unit controls the output region of the output signal from the chlorofluorocarbon concentration detection sensor to be small based on the driving condition of a predetermined gas type. Next, the correction value is loaded from the gas type correction value storage unit, and the raw data is corrected based on this correction value and the raw data output from the Freon gas concentration detection sensor through the amplifier in the output region controlled by the power control unit. Then, the final output value according to a predetermined gas type is calculated from the correction value and the FS correction data loaded from the FS data storage unit by the final output value calculation unit, and this is displayed on the display means.
Therefore, in the present invention, since the power control unit controls the power supplied to the chlorofluorocarbon gas concentration detection sensor so as to limit the output region of the output signal of the chlorofluorocarbon gas concentration detection sensor, the chlorofluorocarbon gas concentration detection is performed except for the reference gas type. output signal area from the sensor is reduced, it is possible to solve the problem of saturation.

Here, in the leak detector, the chlorofluorocarbon gas concentration detection sensor is a semiconductor sensor having a sensitive part configured to include a metal oxide semiconductor, and the power control part controls heater power supplied to the sensitive part. The structure provided with the control part is preferable.
In the present invention of this configuration, when the reaction amount of the chlorofluorocarbon gas is large, by reducing the duty of the pulse voltage supplied from the heater power control unit to the semiconductor sensor, the reaction amount of the chlorofluorocarbon is reduced, and the semiconductor sensor The output area of the output signal can be limited to a small range.

In the leak detector, it is preferable that the heater control unit includes a heater voltage control unit that repeatedly supplies a pulse voltage to the sensitive unit.
In the present invention having this configuration, the pulse peak value supplied from the heater voltage control unit to the chlorofluorocarbon gas concentration detection sensor is a fixed value, but the output from the chlorofluorocarbon gas concentration detection sensor is adjusted by adjusting the ON time and OFF cycle of the pulse. In addition to being able to easily limit the signal output region, the battery power efficiency is good and the battery capacity can be reduced.

In the leak detector, the chlorofluorocarbon gas concentration detection sensor is an infrared sensor that detects an amount of infrared light that reaches the light receiver from the light projector, and the power control unit controls a light amount that is projected from the light projector to the light receiver. The structure provided with is preferable.
In the present invention having this configuration, since the light projection amount and the sensitivity of the chlorofluorocarbon gas are in a proportional relationship, when the reaction amount of the chlorofluorocarbon gas is large, the light projection amount supplied from the light emission amount control unit to the chlorofluorocarbon gas concentration detection sensor is reduced. Thus, the reaction amount of the chlorofluorocarbon gas can be reduced, and the output area of the output signal from the chlorofluorocarbon gas concentration detection sensor can be limited to a small range.

In the leak detector, it is preferable that the light projection amount control unit includes a drive voltage control unit that supplies a pulse voltage or a DC voltage to the projector.
In the present invention of this configuration, the on-time and the pulse period of the pulse supplied from the drive voltage control unit to the projector are fixed, but by adjusting the peak value or DC voltage value of the pulse voltage, The output area of the output signal can be easily limited.

In the above leak detector, it is preferable that the power control unit performs control so that the raw data of the gas type set by the gas type setting unit is aligned with the reference gas type data set in advance.
In the present invention having this configuration, the reference gas type data is used as one gas type data among a plurality of gas types, and the relationship between the reference gas type data and other gas type data is stored in advance. Keep it. In order to control the output area of the output data, the output area of the output data is controlled so that the raw data of the gas type to be measured and the data of the reference gas type are aligned.
Therefore, based on the relationship between the gas species to be measured stored in advance and the reference gas species, the measurement gas can be measured accurately without any amplifier saturation up to the full scale concentration .

1 is a front view of a leak detector according to a first embodiment of the present invention. The block diagram which shows the outline of the leak detector concerning 1st Embodiment. The graph which shows the typical relationship between a sensor output voltage and a heater drive pulse. The graph which shows the relationship between the density | concentration before correction | amendment which carried out power control for every group, and amplifier output voltage. The graph which shows the final output value correct | amended every sensitivity switching. The flowchart of 1st Embodiment. The block diagram which shows the outline of the leak detector concerning 2nd Embodiment of this invention. The graph for demonstrating the subject of a prior art example.

Embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
The first embodiment is an example of a leak detector having a semiconductor sensor as a fluorocarbon gas concentration detection sensor.
1 to 4 show a first embodiment of the present invention. FIG. 1 shows a front view of a leak detector according to the first embodiment, and FIG. 2 shows an outline of the leak detector according to the first embodiment.
In FIG. 1, the leak detector 1 includes a gas acquisition unit 100 that takes in gas, and an apparatus body 3 that is connected to the gas acquisition unit 100.
The gas acquisition unit 100 includes a distal end portion 100A serving as a gas inlet, and a flexible tube 100B that is connected to the distal end portion 100A and feeds air into the apparatus main body 3. The flexible tube 100 </ b> B can be attached to and detached from a hook 3 </ b> A provided on the side surface of the apparatus body 3.

The apparatus main body 3 includes a housing 3B, input means 31 and display means 32 each including a switch or the like provided on the front surface of the housing 3B, a semiconductor sensor 2 provided inside the housing 3B, and the semiconductor. A control device 4 that measures the concentration of the chlorofluorocarbon gas based on an output signal from the sensor 2 and a battery (not shown) are provided.
The semiconductor sensor 2 is a Freon gas concentration detection sensor that detects the concentration of Freon gas, and has a sensitive portion (not shown) configured to include a metal oxide semiconductor.
The input means 31 includes a power switch, a switch for switching the sensitivity range of “H”, “M”, and “L”, a switch for storing the peak time of data, a switch for setting a gas type, and other switches.
The display means 32 includes a bar code type display unit that displays an output value, a display unit that displays a switched range, and the like. These display means 32 are the same as in the prior art. Note that a warning sound output may be added to the display means 32 as necessary.

In FIG. 2, the control device 4 includes a gas type setting unit 41, a storage unit 42, a heater voltage control unit 43 as a power control unit, a sensitivity range setting unit 44, a raw data capturing unit 45, and a calculation unit. 46, an AD conversion unit 47, an amplifier 48, and a display output control unit 49.
The gas type setting unit 41 sets a predetermined gas type among a plurality of gas types of the chlorofluorocarbon gas via the input unit 31. For example, in the present embodiment, examples of the gas species include Freon gas R22, Freon gas R134a, Freon gas R404a, Freon gas R407c, and Freon gas R410. These gases are divided into a reference gas R and other gases A, B, and C. In the present embodiment, the reference freon gas R is usually R22.

The storage unit 42 includes a driving condition storage unit 421 that stores the driving conditions of the semiconductor sensor 2 for each gas type, a gas type correction value storage unit 422 that stores a correction value for each gas type, and a predetermined gas type and sensitivity range “ An FS data storage unit 423 that stores FS correction data relating to the full scale (FS) concentration at which the output voltage output from the amplifier is saturated in response to switching of “H”, “M”, and “L”.
The drive condition storage unit 421 groups a plurality of gas species to be measured in advance, and stores the drive conditions for each group.

The heater voltage control unit 43 limits the output region of the output signal from the semiconductor sensor 2 based on the driving condition of a predetermined gas type set by the gas type setting unit 41 among the driving conditions stored in the driving condition storage unit 421. Thus, the power supplied to the semiconductor sensor 2 is controlled. In this embodiment, the heater power is controlled by repeatedly supplying a pulse voltage to the sensitive part of the semiconductor sensor 2.
FIG. 3 shows the relationship between the sensor output voltage and the heater driving pulse. FIG. 3A is a schematic graph showing the relationship between time and sensor output voltage, and FIG. 3B is a graph showing a pulse wave.
When the heater driving pulse is turned on as shown in FIG. 3B, the sensitive part of the semiconductor sensor 2 is heated, and the sensor output voltage changes to the right as shown in FIG. 3A, as shown in FIG. When the heater drive pulse is turned OFF, the sensitive part of the semiconductor sensor 2 gradually cools, and the sensor output voltage changes to the right as shown in FIG. Thus, in this embodiment, the heater applied power is controlled by repeatedly supplying the pulse voltage to the sensitive part of the semiconductor sensor 2.

FIG. 4 is a graph showing the relationship between the concentration before correction of the gas type power-controlled for each group and the amplifier output voltage. In FIG. 4, for various gases, when the amplifier output voltage exceeds the saturation point F, the same value is obtained regardless of the concentration. The saturation point F is lower than the battery voltage. For example, when the battery voltage is 6V, the amplifier output voltage at the saturation point F is 5V.
In FIG. 4, when the power of the semiconductor sensor 2 is controlled based on the driving conditions stored in the driving condition storage unit 421, the raw data gas A, gas B, and gas C indicated by imaginary lines are indicated by solid lines. When (A, B) and C are obtained and further correction is performed, the gas R shown in the solid line substantially coincides (R≈ (A, B)).

Returning to FIG. 2, the sensitivity range setting unit 44 sets sensitivity ranges of “H”, “M”, and “L” via the input unit 31.
The raw data capturing unit 45 captures raw data output from the semiconductor sensor 2 for each gas type.
The calculation unit 46 generates raw data based on the raw data acquired by the raw data acquisition unit 45 and the correction value stored in the gas type correction value storage unit 422 in the output region controlled by the heater voltage control unit 43. a gas species correction calculation unit 461 corrects, calculates the final output value corresponding from the FS correction data stored in the correction value and the FS data storage unit 423, which is corrected by the gas type correction calculation unit 461 to a predetermined gas species A final output value calculation unit 462.
The final output value calculation unit 462 calculates a final output value corresponding to switching of the sensitivity ranges “L”, “M”, and “H”.
FIG. 5 is a graph showing the final output value corrected for each sensitivity switching. In FIG. 5, the ideal final output value is from 1 to 10 (full scale) corresponding to the switching of the sensitivity ranges “L”, “M”, and “H”.

Next, the CFC gas leakage amount measuring method of this embodiment will be described based on the flowchart of FIG.
The driving conditions of the semiconductor sensor 2 are stored in advance in the driving condition storage unit 421 for each gas type, the correction values are stored in the gas type correction value storage unit 422 for each gas type, and output from the amplifier according to a predetermined gas type. The FS data storage unit 423 stores FS correction data relating to the full scale (FS) concentration at which the output voltage is saturated . That is, a sensitivity calibration operation is performed.
For example, if the concentration of the gas R is 100, the concentration of the gas A is 120, the concentration of the gas B is 130, and the concentration of the gas C is 180, the data close to each other are grouped. The reference gas R is group 1, gas A, B is group 2, gas C is group 3, and group 2, power control for each group is performed by the heater voltage controller 43 so that groups 2 and 3 are close to group 1, respectively. Then, the magnification for each gas of each group with respect to the gas R obtained from the result becomes a correction value that eliminates the deviation between the gases, and is stored in the gas type correction value storage unit 422. For example, if 105 is obtained for group 2 and 106 is obtained for group 3, the ratio to 100 is 0.95 for gas A in group 2, 0.92 for gas B, and for gas C for group 3. 0.95 is the correction value.
The above calibration should be performed regularly and before measurement.
And the semiconductor sensor 2 is installed in a measuring object.
Thereafter, a switch for setting the gas type of the input means 31 is operated, and the gas type setting unit 41 acquires selection information of the gas type, for example, gas A (S1). Thereafter, the heater driving condition of the gas type selected from the driving condition storage unit 421, for example, gas A is loaded (S2). Based on the loaded heater driving condition, the heater power (voltage supplied to the semiconductor sensor 2) is controlled (S3).

On the other hand, the raw data detected by the sensitive unit of the semiconductor sensor 2 is acquired by the raw data capturing unit 45 (S4), and this raw data is generated based on the correction value loaded from the gas type correction value storage unit 422. Is calculated by the gas type correction calculation unit 461 (S5).
Thereafter, gas type correction calculation corrected correction value unit 461 and FS data storage unit 423 predetermined gas species from the stored FS correction data, for example, the final output value calculating unit the final output value corresponding to the gas A Calculation is performed at 462 (S6).
The value and the final output value calculated by the final output value calculation unit 462 are displayed on the display means 32 by the display output control unit 49 (S7).

Accordingly, the following effects can be achieved in the first embodiment.
(1) A gas type setting unit 41 that sets a predetermined gas type, a driving condition storage unit 421 that stores sensor driving conditions for each gas type, and a gas type correction value storage unit that stores correction values for each gas type 422, an FS data storage unit 423 that stores FS correction data relating to the full-scale concentration according to a predetermined gas type, and a predetermined set by the gas type setting unit 41 among the drive conditions stored in the drive condition storage unit 421 A heater voltage control unit 43 as a power control unit for controlling the power supplied to the semiconductor sensor 2 so as to limit the output region of the output signal from the semiconductor sensor 2 based on the driving condition of the gas type, and the heater voltage control unit 43 The raw data is corrected on the basis of the raw data output from the semiconductor sensor 2 for each gas type and the correction value stored in the gas type correction value storage unit 422 in the output region controlled by. Final output value for calculating a final output value corresponding to a predetermined gas type from the correction value corrected by the gas type correction calculation unit 461, the correction value corrected by the gas type correction calculation unit 461, and the correction data stored in the FS data storage unit 423 A calculation unit 462 and display means 32 for displaying the final output value calculated by the final output value calculation unit 462 are provided. Then, the power supplied to the semiconductor sensor 2 is controlled so as to limit the output region of the output signal of the semiconductor sensor 2. For this reason, even if the gas type is changed, measurement with a small sensitivity difference can be performed, and the output signal area from the sensor is reduced except for the reference gas type, and the amplifier 48 is saturated even at full scale (FS). There is nothing.

(2) The semiconductor sensor 2 has a sensitive part including a metal oxide semiconductor, and when the reaction amount of the chlorofluorocarbon gas is large, the duty of the pulse voltage supplied to the semiconductor sensor 2 is reduced. By doing so, the reaction amount of the chlorofluorocarbon gas can be reduced, and the output region of the output signal from the semiconductor sensor 2 can be limited to a small range.

(3) Since the heater voltage control unit 43 is configured to repeatedly supply a pulse voltage to the sensitive unit, the pulse peak value supplied from the heater voltage control unit 43 to the semiconductor sensor 2 is a fixed value, but the pulse ON By adjusting the time and the off period, the output region of the output signal from the semiconductor sensor 2 can be easily limited. Moreover, the battery power efficiency is good and the battery capacity can be reduced.

(4) Since a plurality of gases R, A, B, and C are grouped, and the calibration operation is performed after power control is performed for each of these groups, the magnification for each gas in each group with respect to the gas R can be efficiently set. It can be easily obtained.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.
The second embodiment is an example of a leak detector having an infrared sensor as a fluorocarbon gas concentration detection sensor. Here, in 2nd Embodiment, the component same as 1st Embodiment attaches | subjects the same code | symbol, and abbreviate | omits description.
In FIG. 1, the leak detector 10 includes an apparatus main body 30 connected to a gas acquisition unit 100, and the apparatus main body 30 is based on an infrared sensor 20 that detects the concentration of Freon gas and an output signal from the infrared sensor 20. And a control device 40 for measuring the concentration of the chlorofluorocarbon gas.
The infrared sensor 20 has a general structure including a light projector and a light receiver (not shown), respectively, and has a sensitive unit (not shown) for detecting the amount of infrared rays reaching the light receiver from the light projector.

FIG. 7 is a block diagram of the second embodiment.
In FIG. 7, the control device 40 includes a gas type setting unit 41, a storage unit 42, a drive voltage control unit 430 as a power control unit, a sensitivity range setting unit 44, a raw data capturing unit 45, and a calculation unit. 46, an AD conversion unit 47, an amplifier 48, and a display output control unit 49.
The drive voltage control unit 430 limits the output region of the output signal from the infrared sensor 20 based on the drive condition of the predetermined gas type set by the gas type setting unit 41 among the drive conditions stored in the drive condition storage unit 421. As described above, the amount of light projected from the light projector to the light receiver of the infrared sensor 20 is controlled. In this embodiment, the driving voltage for supplying a pulse voltage or a DC voltage to the light projector is controlled.
In the second embodiment, the gas type set by the gas type setting unit 41 is the same as that in the first embodiment, but the standard freon gas R is R134a.
The CFC gas leakage amount measuring method of the second embodiment is the same as the CFC gas leakage amount measuring method of the first embodiment.

In the second embodiment, in addition to the same effects as (1) of the first embodiment, the following effects can be achieved.
(5) The Freon gas concentration detection sensor is an infrared sensor 20 that detects the amount of infrared rays that reach the light receiver from the projector, and the drive voltage control unit 430 as a power control unit controls the amount of light that is projected from the light projector to the light receiver. Therefore, when the reaction amount of the chlorofluorocarbon gas is large, the amount of chlorofluorocarbon gas reaction is reduced by reducing the amount of light supplied to the infrared sensor 20, and the output area of the output signal from the infrared sensor 20 is small. Can be limited to a range.

(6) Since the drive voltage control unit 430 is configured to supply a pulse voltage or a DC voltage to the projector, the output region of the output signal from the infrared sensor 20 can be adjusted by adjusting the peak value or the DC voltage value of the pulse voltage. Can be easily limited.

Note that the present invention is not limited to the above-described embodiments, and includes other configurations that can achieve the object of the present invention, and includes the following modifications and the like.
For example, in the above-described embodiment, a plurality of gases R, A, B, and C are grouped, and power control is first performed for each of these groups. However, in the present invention, grouping is not necessarily required. For example, when the gas A is the measurement target among the gas A, the gas B, and the gas C, power control is performed by the heater voltage control unit 43 so that the gas A approaches the gas R. The magnification of the gas A with respect to the gas R obtained from the result is a correction value that eliminates the deviation between the gases, and is stored in the gas type correction value storage unit 422. Similarly, when the gas B is a measurement target, the heater voltage control unit 43 performs power control so that the gas A approaches the gas R, and the correction value is stored in the gas type correction value storage unit 422.

Furthermore, in the present invention, as long as the power supplied to the chlorofluorocarbon gas concentration detection sensor is controlled so as to limit the output region of the output signal from the concentration detection sensor, the configuration of the first embodiment and the second embodiment is used. It is not limited.
In the first embodiment, the semiconductor sensor is built in the apparatus main body 3. However, in the present invention, a cord may be connected to the apparatus main body 3 and a sensitive portion may be provided at the tip of the cord.
In the present invention, the load resistance may be increased or decreased in order to control the sensitivity of the CFC gas concentration detection sensor. The control by the load resistance includes a method of increasing / decreasing the load resistance which is indirectly power control.
The sensing unit is greatly affected by the heater, but the current flowing into the sensing unit changes as the load resistance increases or decreases.

  DESCRIPTION OF SYMBOLS 1,10 ... Leak detector, 2 ... Semiconductor sensor (Freon gas concentration detection sensor), 20 ... Infrared sensor (Freon gas concentration detection sensor), 3, 30 ... Apparatus main body, 41 ... Gas type setting part, 421 ... Drive condition memory | storage part, 422 ... Gas type correction value storage unit, 423 ... FS data storage unit, 43 ... Heater voltage control unit (power control unit), 430 ... Drive voltage control unit (power control unit), 461 ... Gas type correction calculation unit, 462 ... Final output value calculation unit, 32 ... display means, 48 ... amplifier

Claims (7)

A fluorocarbon gas concentration detection sensor that detects the concentration of the fluorocarbon gas, and an apparatus main body that measures the concentration of the fluorocarbon gas based on an output signal from the fluorocarbon gas concentration detection sensor,
The device body is
An amplifier for amplifying a signal output from the fluorocarbon gas concentration detection sensor;
A gas type setting unit for setting a predetermined gas type among a plurality of gas types of chlorofluorocarbon gas;
Driving condition storage unit that stores the driving condition of the freon gas density detection sensor for each of the gas species, gas type correction value storage unit for storing a correction value to eliminate the gas species of the deviation, and in response to said predetermined gas species Storage means having an FS data storage unit for storing FS correction data relating to a full-scale concentration at which the output voltage output from the amplifier is saturated ;
The chlorofluorocarbon gas limits the output region of the output signal from the chlorofluorocarbon gas concentration detection sensor based on the driving conditions of a predetermined gas type set by the gas type setting unit among the driving conditions stored in the driving condition storage unit. A power control unit for controlling power supplied to the concentration detection sensor; and raw data output from the Freon gas concentration detection sensor through the amplifier for each gas type in the output region controlled by the power control unit and the gas type correction A gas type correction calculation unit that corrects the raw data based on the correction value stored in the value storage unit, a correction value corrected in the gas type correction calculation unit, and an FS correction stored in the FS data storage unit A calculation means having a final output value calculation unit for calculating a final output value according to the predetermined gas type from the data ;
Display means for displaying the final output value computed by the computing means;
Leak detector characterized by comprising. The leak detector according to claim 1,
The Freon gas concentration detection sensor is a semiconductor sensor having a sensitive part configured to include a metal oxide semiconductor,
The leak detector according to claim 1, wherein the power control unit includes a heater power control unit that controls power supplied to the sensitive unit. The leak detector according to claim 2,
The leak detector according to claim 1, wherein the heater power control unit includes a heater voltage control unit that repeatedly supplies a pulse voltage to the sensitive unit. The leak detector according to claim 1,
The Freon gas concentration detection sensor is an infrared sensor that detects the amount of infrared rays reaching the light receiver from the projector,
The leak detector according to claim 1, wherein the power control unit includes a light projection amount control unit that controls a light amount projected from the light projector to the light receiver. The leak detector according to claim 4,
The leak detector includes a drive voltage controller that supplies a pulse voltage or a DC voltage to the projector. The leak detector according to any one of claims 2 to 5,
The power control unit aligns raw data of the gas type set by the gas type setting unit with data of a reference gas type set in advance. In the method for measuring the amount of leakage of chlorofluorocarbon, the output signal from the chlorofluorocarbon concentration sensor is amplified by an amplifier, and the amount of leakage of chlorofluorocarbon is measured based on the output from the amplifier .
The driving condition storage unit stores the driving condition of the chlorofluorocarbon gas concentration detection sensor for each gas type, and the gas type correction value storage unit stores a correction value that eliminates the deviation for each gas type, according to the predetermined gas type. The FS data storage unit stores FS correction data relating to the full scale concentration at which the output voltage output from the amplifier is saturated .
The power control unit detects the chlorofluorocarbon gas concentration so as to limit an output region of an output signal from the chlorofluorocarbon gas concentration detection sensor based on a driving condition of a predetermined gas type set among driving conditions stored in the driving condition storage unit. Control the power supplied to the sensor,
Gas species on the basis of the stored correction value by said power control the gas species from said chlorofluorocarbon gas density detection sensor for each of the gas species in controlled output area and the raw data output through the amplifier part correction value storage unit The correction calculation unit calculates the raw data, and finally calculates the final value corresponding to the predetermined gas type from the correction value corrected by the gas type correction calculation unit and the FS correction data stored in the FS data storage unit. The final output value calculation unit calculates the output value,
The display means displays the final output value calculated by the calculating means.
A method for measuring the leakage amount of chlorofluorocarbon gas.

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