JP2007064699A - Quantitative measuring instrument of gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a quantitative measuring instrument of a gas capable of appropriately corresponding to an animal from an extremely small experimental animal to a relatively large experimental animal even if the detection capacity of a detection part is raised in spite of a compact and simple constitution. <P>SOLUTION: The quantitative measuring instrument of the gas is equipped with a gas flowing route 3 for guiding the gas from its one end to discharge it to its other end, a closed housing container 5, the detection part 27 for allowing the gas, which is discharged from the housing container 5 to flow in to detect the same, a bypass route 39 for guiding the gas so as to bypass the detection part 27, the solenoid valve 41 for connecting the gas flowing route (detection route 38) passed through the detection part 27 and the bypass route 39 in a changeable manner and a controller 45 for controlling the solenoid valve 41 at a predetermined time interval. An H<SB>2</SB>SO<SB>4</SB>solution is put in an ammonia absorbing bin 29 so that the flow rates of the gas become same even if the gas is passed through all of the routes and air passing resistance is adjusted by the surface height of the H<SB>2</SB>SO<SB>4</SB>solution to limit the flow rate of the gas. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a gas quantitative measurement device, and more particularly to a gas quantitative measurement device capable of quantitatively measuring gas with high accuracy while having a simple configuration.

Gas analysis methods are broadly divided into chemical analysis methods (titration method, adsorption weight method, etc.) and instrumental analysis methods (gas chromatographic method, non-dispersive infrared absorption method). The method is appropriately adopted.
Considering the case in which the gas to be measured flows through the tube and carbon dioxide (carbon dioxide gas) in the gas is quantified, the former method introduces the gas to be measured into a bottle filled with NaOH and samples it before sampling barium chloride. In contrast, in the latter method, a part of the gas to be measured is sampled and sampled and then analyzed by an analytical instrument, and the whole is estimated from the result.
In the former method, all target components are sampled from the gas to be measured, so even if the gas flow rate changes slightly during the measurement, the quantitative accuracy is not affected. When the gas flow rate changes, the result is greatly affected. Therefore, in order to improve the quantitative accuracy, a highly accurate gas amount control means is required, the equipment cost is increased, and maintenance is troublesome. A calibration operation is also required.
On the other hand, in the former method, the titration operation is complicated, and in continuous measurement over a long period, errors due to operation errors and individual differences in operation are included in the quantitative value, so experimental animals are limited to small animals such as mice. In contrast, the number of specimens is small and the measurement time must be shortened. On the other hand, in the latter method, the analysis time itself is short and can be automated.

Therefore, the present inventor has already proposed an apparatus for measuring the amount of carbon dioxide generated by respiration of an experimental animal in the following patent document as an apparatus that takes advantage of the chemical analysis method and the instrumental analysis method. In this measuring device, the container and the detection unit are connected by a gas flow path, and when an experimental animal is bred in the storage container, all the air containing carbon dioxide exhausted by the respiration of the experimental animal is passed to the detection unit. All of the carbon dioxide introduced and sampled is sampled and then the sampled carbon dioxide is converted to something that can be measured gravimetrically. Therefore, the advantages of sampling the entire amount are used as they are, and while the measurement accuracy is high accuracy of 1/100 or more, highly accurate gas amount control means and calibration operation are unnecessary. In addition, since the sampled carbon dioxide is quantified by the gravimetric method, it is free from complicated operations such as titration, and the time required for measuring the weight is about 1 minute. Therefore, it is possible to measure the amount of carbon dioxide generated over a long period of time.
If the carbon dioxide generation amount (weight) can be measured using the above apparatus, the carbon dioxide concentration (%) in the exhalation of the experimental animal can be calculated by substituting the measured value into the following equation.
Cw = 44 × (Cc−Cb) × F × 1440/22400
Here, Cw: carbon dioxide generation amount due to respiration (g / day)
Cc: Carbon dioxide concentration in exhaled breath (%)
Cb: Carbon dioxide concentration in air (%)
F: Amount of air (mL / min) supplied to the closed container

JP2003-329672A

In the above measurement device, since sampling of the total amount of carbon dioxide, which is the target component, is a principle, the configuration is such that the air exhausted from the container is guided to the total amount detection unit, and the experimental animal is a mouse. In the case of a minimum such as a rat or the like, the use of the above apparatus is appropriate, but if the experimental animal becomes relatively large like a rabbit, the respiration rate increases, so that the detection capability is immediately exceeded. When the capacity is increased, the apparatus must be increased in size, resulting in troublesome maintenance management and handling.
In addition, in order to minimize the measurement error, it is necessary to prevent gas from leaking out of the storage container. However, manufacturing the storage container in a highly accurate and airtight structure also has design and manufacturing errors. Therefore, it is practically difficult, and it is particularly difficult to produce a high airtightness without sacrificing the convenience of taking in and out with an apparatus that is premised on taking in and out laboratory animals, that is, opening and closing.

Therefore, in order to solve the above-mentioned problems, the present invention improves the previously proposed apparatus, and has a compact and simple configuration, but without increasing the detection capability of the detection unit, it can be used for relatively large experiments. An object of the present invention is to provide a gas quantitative measurement apparatus that can appropriately handle animals.
Another object of the present invention is to provide a gas quantitative measurement device with a small measurement error with a simple configuration.

In order to solve the first problem, the present inventors continuously sample over the entire work time while adopting the method of sampling the total amount of gas flowing into the path from the inside of the container. Instead, sampling was performed for a certain period of time, that is, fractionation was performed, and the result for the total amount of gas was estimated from the detection result. Specifically, a sampling path and a non-sampling path that can be switched are provided as gas inflow paths, and the switching time interval is controlled, and gas passes through any of the sampling path and non-sampling path. We developed a device with the same flow rate and succeeded in obtaining highly reliable estimation results from the collected samples.
Further, in order to solve the second problem, focusing on the fact that when the gas is supplied to the storage container by a pump and the gas discharged as a result is guided to the detection unit, the inside of the processing container becomes a pressurized atmosphere, the storage container As a result, the inside of the container was made into a negative pressure atmosphere by sucking the gas from the gas and introducing the gas to the detection unit, and the gas was successfully prevented from leaking outside.

  The invention according to claim 1 is provided in a gas flow path for introducing gas from one end and discharging it to the outside at the other end, a closed system storage container provided in the gas flow path, and a gas flow path downstream from the storage container. And a detection unit for detecting an arbitrary component of the gas coming out of the storage container, in parallel with the detection path configured by a part of the gas flow path and passing through the detection unit A bypass path, a path switching unit that connects the detection path and the bypass path in a switchable manner, a control unit that controls the path switching unit at predetermined time intervals, and a gas that passes through any of the paths. However, there is provided a gas flow rate adjusting means for adjusting the gas flow rate to the same amount.

  According to a second aspect of the present invention, in the gas quantitative measurement apparatus according to the first aspect, the gas flow rate adjusting means is provided before branching into the detection path and the bypass path, and the ventilation resistance of the detection path and the bypass path It is a gas quantitative measurement apparatus characterized by comprising a ventilation resistance portion that is the same as or exceeds the larger ventilation resistance.

  According to a third aspect of the present invention, there is provided the gas quantitative measurement apparatus according to the second aspect, wherein the ventilation resistance portion includes an intake bottle containing a liquid whose liquid surface height is adjusted so as to form a ventilation resistance of a predetermined size, A gas quantitative measurement device comprising a gas flow path for introducing gas into a liquid.

  According to a fourth aspect of the present invention, in the gas quantitative measurement apparatus according to any one of the first to third aspects, the suction unit is provided in the gas flow path on the downstream side of the storage container, and the gas in the storage container is suctioned to thereby A gas quantitative measurement apparatus characterized in that a gas is guided to a detection unit while the inside of a container is in a negative pressure atmosphere.

  According to a fifth aspect of the present invention, there is provided a gas distribution path through which gas is introduced from one end and discharged outside at the other end, a closed system storage container provided in the gas distribution path, and a gas distribution path downstream of the storage container. And a gas quantitative measurement apparatus comprising a detection unit that detects an arbitrary component of the gas that has come out of the storage container, and a suction means is provided in a gas flow path downstream of the storage container, The gas quantitative measurement apparatus is characterized in that the gas is guided to the detection unit while the inside of the container is made into a negative pressure atmosphere by sucking the gas.

  A sixth aspect of the present invention is the gas quantitative measurement apparatus according to any one of the first to fifth aspects, wherein the quantitative gas measurement apparatus is used for quantitatively measuring a respiration rate of an experimental animal.

The gas quantitative measurement apparatus of the present invention is an improved apparatus that takes advantage of the chemical analysis method and the instrumental analysis method, and has a compact and simple configuration, and is a minimal laboratory animal without increasing the detection capability of the detection unit. From large to large laboratory animals.
In addition, the gas quantitative measurement device of the present invention has a simple configuration but a small measurement error.

An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 schematically shows a quantitative measurement apparatus (experimental series) 1 for the amount of carbon dioxide generated by respiration of a relatively large laboratory animal (for example, a rabbit).
Reference numeral 3 denotes a gas flow path, one end being an air supply port and the other end being an air discharge port. A container 5 is disposed in the gas flow path 3.
As shown in FIGS. 2 and 3, the storage container 5 is integrally made of a transparent synthetic resin. Moreover, the storage container 5 has a square shape, and the front surface is open. A flange 7 that extends outward is formed on the front surface. A transparent laminating plate 9 is applied to the flange 7, and a plurality of flanges 7 and the laminating plate 9 are fixed by a U-shaped fixture 11. A closed system is established by fixing between and. Note that an O-ring 13 is bonded to a portion of the mating plate 9 that is in contact with the flange 7, so that the airtightness of the mating portion is maintained to some extent.

A horizontal through passage 15 extends partway through the bottom plate of the storage container 5, and a plurality of gas inlets 17 are formed in the horizontal through passage 15. The air flows into the storage container 5 through 17. In addition, a horizontal through passage 19 extends partway along the upper surface, and a plurality of gas outlets 21 are formed in the horizontal through passage 19, and one of the gas outlets 21 passes through the horizontal through passage 19. Thus, the air flows out from the storage container 5 to the gas flow path 3.
A cock 23 is provided in the gas flow path 3 connected to the horizontal through path 15, and air flows into the gas flow path 3 when the cock 23 is opened.

  A mesh cage 25 is disposed in the storage container 5. Since the rabbit can be placed in the storage container 5 in a state of being placed in the cage 25, it is possible to prevent the operator from being bitten and to reduce the breeding stress of the experimental animal because it is not necessary to capture it.

Reference numeral 27 denotes a detection unit. The detection unit 27 is configured such that the ammonia absorption bottle 29, the first dehumidification cylinder 31, the second dehumidification cylinder 33, the collection cylinder 35, and the moisture absorption cylinder 37 are detachable from below via a connection part. It is assembled.
In the ammonia absorption bottle 29, in order to remove ammonia (NH ₃ ) contained in the air flowing out from the storage container 5 through a pipe forming a part of the gas flow path 3, 1M-H ₂ SO ₄ ( Liquid). The first dehumidifying cylinder 31 and the second dehumidifying cylinder 33 are provided with silicon dioxide (SiO ₂ ) and silicon dioxide (SiO ₂ ) in order to remove water (H ₂ O) contained in the air from which ammonia (NH ₃ ) has been removed. SiO ₂ ) and calcium chloride (CaCl ₂ ) are filled.

The collection cylinder 35 is filled with soda lime (NaOH). When the air from which ammonia (NH ₃ ) and water (H ₂ O) were removed passed, carbon dioxide (CO ₂ ) gas contained in the air was converted to sodium carbonate (Na ₂ CO ₃ ) by the following chemical reaction. Above it is fixed and collected on soda lime.
2NaOH + CO ₂ → Na ₂ CO ₃ + H ₂ O
The moisture absorption cylinder 37 is filled with calcium chloride (CaCl ₂ ) in order to absorb moisture (H ₂ O) generated by the chemical reaction. Water is absorbed by the water absorption cylinder 37.

The air flowing into the detection path 38 which is a part of the gas flow path 3 from the container 5 passes through the detection unit 27 on the way, and further downstream gas via an electromagnetic valve 41 (three-way valve) as path switching means. Merge with distribution channel 3.
On the other hand, reference numeral 39 indicates a bypass path, and this bypass path 39 extends from the upper part of the ammonia absorption bottle 29 and joins the downstream gas flow path 3 via an electromagnetic valve 41 as a path switching means.
Reference numeral 43 denotes an absorber composed of a carbon dioxide (carbon dioxide) absorbent, and the absorber 43 is provided in the bypass path 39. By providing such an absorber 43 in the bypass path 39, carbon dioxide has already been absorbed and removed even if air accumulated in the bypass path 39 flows backward to the detection section 27 at the time of path switching. There is no significant effect on the amount of sodium carbonate collected.

In the above-described configuration, the ventilation resistor is configured by the ammonia absorption bottle 29 and the pipe as the gas flow path 3 that guides air into the liquid contained therein, and the ventilation level is adjusted by adjusting the liquid level. The magnitude of the resistance can be adjusted.
The magnitude of the ventilation resistance is set equal to or greater than the larger ventilation resistance by comparing the ventilation resistance of the detection path 38 and the ventilation resistance of the bypass path 39. It is preferable that the ventilation resistance of the ventilation resistor is set larger than the ventilation resistance of the path to ensure adjustment of the gas flow rate.
By setting the airflow resistance in this way, the airflow resistance of the airflow resistance body controls the gas flow rate of the path, and the gas that has passed through the airflow resistance body passes through the bypass path 39 even if it passes through the detection path 38. Even so, the gas flow rate is the same.
The ventilation resistor having the above configuration can adjust the ventilation pressure most easily as far as it can be conceived.

Reference numeral 45 denotes a controller as a control means for controlling switching of the electromagnetic valve 41. In response to a command from the controller 45, the electromagnetic valve 41 switches the path and connects the detection path 38 and the gas flow path 3 downstream thereof. Then, the detection state is set, or the bypass path 39 and the gas flow path 3 on the downstream side are connected to set the bypass state.
The controller 45 performs sequencer control according to a predetermined time interval. For example, the cycle (Ttotal = 10 minutes) in which the detection path 38 is connected to Ton (for example, 1 minute) and the path is switched to connect the bypass path to Ton (for example, 9 minutes) is repeated. By switching the connection in this way, not the total gas amount but the 1/10 amount of gas is introduced to the detection unit 27. Therefore, the detection capability required for the detection unit 27 is 1/10 of the total amount. Will be enough.

Reference numeral 47 indicates a manual cock for adjusting the flow rate of gas passing through the gas flow path 3.
Reference numeral 49 denotes a floating ball type flow meter, and the gas flow rate can be confirmed by the flow meter 49.

Reference numeral 51 denotes a suction pump, and the suction pump 51 is provided at the outlet of the gas flow path 3. When the suction pump 51 is operated, outside air is sucked as indicated by an arrow, passes through the detection path 38 or the bypass path 39, and finally passes through the gas flow path 3 and is finally discharged outside.
When sucked as described above, the inside of the storage container 5 is in a negative pressure atmosphere, so even if there are a few holes, air does not leak out from there, and all the air in the storage container 5 It is guided to the gas distribution path 3.

In actual measurement work, at least two systems having the same specifications are arranged, and air is supplied under the same conditions in each system. Normally, the gas quantitative measurement device 1 of FIG. 1 is the experimental series (1), and the remaining one series (experimental series (2)) quantifies the total amount of carbon dioxide contained in the air supplied to the container 5. It is used as a reference series for measuring, that is, for checking the safety of the device, and no animals are raised in the container 5.
In addition to the above-described series, when some kind of treatment is performed on the experimental animals, a control experiment series in which untreated laboratory animals are bred in the storage container 5 is further employed.
The tip of each line is connected to a header (not shown), and the air once accumulated in the header is supplied to each line.

Next, the procedure of measurement work will be described.
First, the weights of the collection tubes 35 (filled with soda lime (NaOH)) and the moisture absorption tube 37 of each series are measured, and then each series is arranged so as to have the configuration shown in FIG. The weight is measured with an electronic balance having a sensitivity of 10 mg or less. After placing the experimental animal in the cage 25 of the experimental series, the cage 25 is closed in the container 5 with the laminated plate 9 or the like as described above. The reference series cage 25 is placed in the receiving container 5 while being empty and is similarly closed. And the inside of the container 5 is controlled to a fixed temperature by a heater and a temperature sensor (not shown).

When the cocks 23 and 47 are opened and the suction pump 51 is operated after the above preparatory work is completed, air starts to flow in from the supply ports of the gas flow paths 3 of the respective series.
Then, when the detection path 38 is connected to the downstream gas flow path 3 by the electromagnetic valve 41, it passes through the detection unit 27 and is then discharged out of the apparatus from the discharge port of the gas flow path 3. On the other hand, when the bypass system communicates with the electromagnetic valve 41, the electromagnetic valve 41 does not pass through the detection unit 27 and is discharged out of the apparatus through the discharge port of the gas flow path 3.

After the end of the predetermined measurement time, the collection cylinder 35 and the moisture absorption cylinder 37 of each series are removed, and the weight is measured in the same manner as before the measurement work. Then, taking into account that the weight change data before and after the measurement operation of the collection cylinder 35 and the moisture absorption cylinder 37 of each series is converted into sodium carbonate (Na ₂ CO ₃ ), the collection of each series. The amount (weight) of carbon dioxide (CO ₂ ) collected in the cylinder 35 is calculated. The amount of carbon dioxide obtained by subtracting the amount of carbon dioxide generated in series (2) from the amount of carbon dioxide generated in series (1) is the total amount of carbon dioxide generated by respiration during the breeding period in the experimental animal container 3 Cwp (g / Day). However, the total amount of carbon dioxide generated is measured on the collected air.
Carbon dioxide generation amount Cw for the total amount of supplied air is
Cw = Cwp × (Ttotal / Ton)
Therefore, it can be estimated easily and reliably.

Although the embodiment of the present invention has been described above, the specific configuration of the present invention is not limited to the above-described embodiment, and even if there is a design change within a range not departing from the gist of the present invention. Included in the invention.
For example, the gas to be detected is not limited to normal air, and various types of gases such as exhaust gas from a diesel engine can be used.
The container is not limited to experimental animals but may be a plant or the like.
Further, the number of bypass paths is not limited to one, and a plurality of bypass paths may be provided. Further, another detector may be provided in the bypass path, and two or more detections may be performed simultaneously. For example, if an oxygen or hydrogen sulfide detector is provided in the bypass passage 39, the oxygen amount and the hydrogen sulfide amount can be detected simultaneously with the carbon dioxide amount.
Furthermore, if it is dried by passing through a desiccant such as silica before supplying the air to be supplied to the storage container 5, the humidity in the storage container 5 is suitable for raising animals continuously for a long time. As a result, the carbon dioxide generation amount can be measured continuously over a long period of time.

Using the gas quantitative measurement apparatus described in the above embodiment, the amount of carbon dioxide generated by respiration of two sibling mice (mutants) born on the same genetic day was measured.
In this experiment, it took about 30 minutes for the weight measurement. The operation time of the device itself was 3 days.
The amount of carbon dioxide generated can be easily calculated by simply subtracting and adding the measurement results.
Thus, unlike the conventional titration method, the gravimetric method does not require a complicated calculation technique, and the accuracy of the data is high, which is an accuracy of 1/100 or more. The measurement can be performed within an error range of 10 mg with respect to 5 g of carbon dioxide generated by one mouse per day.

The following table shows the measurement results. The measurement date and time was August 8-22, 2005.

The gas quantitative measurement device of the present invention is capable of quantitatively measuring gas with high accuracy while having a compact and simple configuration.
Further, when the gas in the container is guided from the upstream side to the downstream detection unit by suction, the noise is smaller than in the case where the gas is supplied into the container by pressure feeding as in the conventional case. Therefore, it is possible to reduce the stress applied to the experimental animal without specially silencing. Therefore, it is suitable for exposure animal testing.
Furthermore, since the gas quantitative measurement device of the present invention does not leak gas directly from the storage container, it can be used in experiments in which isotopes and the like are handled in the storage container.

It is a schematic diagram of the gas quantitative measurement apparatus which concerns on embodiment of this invention. It is a perspective view of a storage container. It is a disassembled perspective view of a storage container. It is a graph of an experimental result.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Gas fixed-quantity measuring device 3 ... Gas distribution path 5 ... Container 7 ... Flange 9 ... Lamination board 11 ... Fixing fixture 13 ... O-ring 15 ... Horizontal through-channel 17 ... Gas inflow port 19 ··· Horizontal through passage 21 ··· Gas outlet 23 · · · Cock 25 · · · Cage 27 · · · Detection unit 29 · · · Ammonia absorption bottle 31 · · · First dehumidification tube 33 · · · Second dehumidification tube 35 · · · Collection tube 37 ... Water absorption cylinder 38 ... Detection path 39 ... Bypass path 41 ... Solenoid valve 43 ... Absorber 45 ... Controller 47 ... Cock 49 ... Flow meter 51 ... Suction pump

Claims (6)

A gas flow path through which gas is introduced from one end and discharged to the outside at the other end; a closed system storage container provided in the gas flow path; and a gas flow path downstream from the storage container; In a gas quantitative measurement device equipped with a detection unit for detecting an arbitrary component of the gas
A bypass path configured in parallel with a detection path configured by a part of the gas flow path and passing through the detection unit;
A path switching means for connecting the detection path and the bypass path in a switchable manner;
Control means for controlling the route switching means at predetermined time intervals;
A gas flow rate adjusting means for adjusting the gas flow rate to the same amount regardless of which gas passes through;
A gas quantitative measurement device characterized by comprising:   2. The gas quantitative measurement apparatus according to claim 1, wherein the gas flow rate adjusting means is provided before branching into the detection path and the bypass path, and is the same as the larger one of the ventilation resistance of the detection path and the ventilation resistance of the bypass path. Or a quantitative gas measuring apparatus, characterized by comprising a ventilation resistance part exceeding it.   3. The gas quantitative measurement apparatus according to claim 2, wherein the ventilation resistance portion includes an intake bottle containing a liquid whose liquid surface height is adjusted so as to form a ventilation resistance of a predetermined size, and a gas for guiding the gas into the liquid. A gas quantitative measurement apparatus characterized by comprising a distribution channel.   4. The quantitative gas measuring apparatus according to claim 1, wherein a suction means is provided in a gas flow path downstream of the storage container, and the gas in the storage container is sucked to thereby create a negative pressure atmosphere in the storage container. A gas quantitative measurement device characterized in that the gas is guided to the detection unit while A gas flow path through which gas is introduced from one end and discharged to the outside at the other end; a closed system storage container provided in the gas flow path; and a gas flow path downstream from the storage container; In a gas quantitative measurement device equipped with a detection unit for detecting an arbitrary component of the gas
Gas quantification characterized in that a suction means is provided in a gas flow path downstream of the storage container, and the gas is guided to the detection unit while the storage container is in a negative pressure atmosphere by sucking the gas in the storage container. measuring device. 6. The quantitative gas measuring apparatus according to claim 1, wherein the quantitative gas measuring apparatus is used for quantitatively measuring a respiration rate of an experimental animal.

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