JP2006078434A - Sample gas supply device and inflammable gas detection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sample gas supply device of novel constitution capable of inspecting easily detection performance of a gas sensor, and an inflammable gas detection system provided with the sample gas supply device. <P>SOLUTION: This sample gas supply device for supplying a gas sample for inspection used when inspecting the detection performance of the gas sensor for detecting inflammable gas is provided with a sample gas generator in which a sample gas source impregnated with a liquid hydrocarbon for generating the inflammable gas by evaporation into a filling material for impregnation is arranged inside a sealed container. This inflammable gas detection system of the present invention includes a gas sampling device for monitoring provided with a gas detecting part for detecting the inflammable gas, a gas suction means, an alarm notification mechanism, and the sample gas supply device described hereinbefore for supplying the gas sample used when inspecting the detection performance of the gas detecting part carried out from time to time, separately from the detection performance inspection for the gas detecting part carried out periodically in every prescribed period. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides a flammable gas detection system for detecting a flammable gas, and an inspection sample gas used for inspecting the detection performance of gas detection means constituting the flammable gas detection system. The present invention relates to a sample gas supply device.

  At present, for example, in an automobile manufacturing factory, when a drying process of a paint applied to a car body is performed, it is possible to prevent the occurrence of problems such as ignition of flammable gas generated in a drying furnace. For the purpose of ensuring safety, a monitoring gas sampling device is installed to monitor the concentration of combustible gas in the environmental atmosphere in the drying furnace.

FIG. 2 is a block diagram showing a schematic configuration of an example of a combustible gas detection system provided with a conventional monitoring gas sampling device.
The combustible gas detection system 60 monitors the concentration of the combustible gas, that is, monitors that the test gas that is the environmental atmosphere of the inspection target space S is introduced from the inspection target space S where the detection of the combustible gas is to be performed. Gas sampling device 61 and control device 65 for controlling the operation of each component constituting combustible gas detection system 60, and the test gas is sucked by gas suction means 63 in monitoring gas sampling device 61. For example, the gas detection means 62 introduces a combustible gas having a predetermined concentration or more into the gas to be detected, which is introduced into the gas detection section including the gas detection means 62 configured by a contact combustion type gas sensor. An alarm is issued upon detection.

  Generally, in the gas detection means 62 of such a combustible gas detection system 60, when the gas sensor deteriorates with time or for other reasons with use, and the detection performance of the gas sensor falls below a certain level, Due to the nature of the application, it becomes extremely dangerous, so it is obliged to inspect the detection performance of the gas sensor, including the calibration of the gas sensor, once every predetermined period, for example every six months. .

  In the inspection of the detection performance of the gas sensor, for example, a cylinder loaded with a standard gas for inspection is connected through a standard gas supply path 67 connected to a main gas introduction path 66 for introducing a test gas into the gas detection section. The standard gas supply device 70 having the reference numeral 71 and the like supplies the standard gas for inspection to the gas detection means 62, and the gas detection means 62 detects the concentration of the standard gas for inspection. The degree of reduction is confirmed, and the required calibration process is performed based on the result.

In addition, as one of the regular inspection methods for gas sensors, combustible gases other than the gas to be detected by the gas sensor can be used in order to prevent the gas sensor from degrading the gas selection performance due to the degradation of the gas sensor detection performance. A method has been proposed in which the degree of deterioration of a gas sensor is confirmed by detecting the concentration of the inspection gas, which is used as an inspection gas (see Patent Document 1).
JP 2002-286669 A

However, the actual situation is that the calibration of the gas sensor is performed only periodically. For example, at the start of work every morning, that is, at the start of the monitoring operation, a state where the desired detection performance of the gas sensor is exhibited ( An operator cannot know whether or not it is in an active state.
In addition, normal gas sensor detection performance inspection, including gas sensor calibration, is cumbersome and takes a long time. Therefore, if the detection performance inspection of the gas sensor is performed every time a monitoring operation is started, the work efficiency is greatly increased. And the inspection cost is considerably increased.

  As described above, in the field where the monitoring operation of the combustible gas in the environmental atmosphere is required, there is a risk that the detection performance of the gas sensor may be deteriorated due to the deterioration of the gas sensor, etc. It is important that the worker recognizes the activated state of the gas sensor at the start of the monitoring operation.

  The present invention has been made on the basis of the above circumstances, and is a novel that can easily perform a detection performance inspection of a gas sensor separately from a detection performance inspection of a gas sensor that is periodically performed. It is an object of the present invention to provide a sample gas supply device having a configuration and a combustible gas detection system including the sample gas supply device.

The sample gas supply device of the present invention is for supplying a sample gas for inspection used when inspecting the detection performance of a gas sensor for detecting a combustible gas,
It is characterized by comprising a sample gas generator in which a sample gas source formed by impregnating a filler for impregnation with a liquid hydrocarbon that is vaporized to generate a combustible gas is disposed in an airtight container.

In the sample gas supply device of the present invention, it is preferable to use ethyl alcohol or methyl alcohol as the liquid hydrocarbon constituting the sample gas source.
Moreover, in the sample gas supply device of the present invention, it is preferable that the sealed container is configured so that the sample gas source can be replaced.

A combustible gas detection system according to the present invention includes a monitoring gas sampling device including a gas detection unit for detecting a combustible gas, and a gas suction for introducing a test gas or a sampling gas for inspection into the gas detection unit. In addition to the means, the alarm notification mechanism for issuing an alarm based on the detection result by the gas detection unit, and the detection performance inspection of the gas detection unit periodically performed every predetermined period, the gas detection unit A sample gas supply device for supplying a sample gas for inspection used when performing detection performance inspection;
The sample gas supply device is composed of the above-described one.

  In the combustible gas detection system of the present invention, in the detection performance inspection of the gas detection unit that is performed as needed, the gas detection unit indicates that the concentration of the sampling gas for inspection supplied to the gas detection unit is a predetermined value or more. It can be configured such that an alarm is issued by the alarm notification mechanism when it is detected, and a dangerous gas concentration value that triggers an alarm when the detection performance of the gas detector is inspected is issued during a monitoring operation. It can be set lower than the dangerous gas concentration value as a trigger.

  According to the sample gas supply device of the present invention, it is possible to stably supply the sample gas for inspection used when inspecting the detection performance of the gas sensor for detecting combustible gas to the gas sampling device for monitoring. At the same time, the sample gas for inspection can be obtained at a lower cost than the standard gas for inspection used in the detection performance inspection of the gas sensor that is regularly performed. Can be done.

  According to the combustible gas detection system of the present invention, the inspection of the gas sensor at the start of the monitoring operation can be easily performed at a low inspection cost, whereby the gas caused by the deterioration of the gas sensor over time, etc. The degree of deterioration of detection performance can be known, and if necessary, the gas sampling device can be kept in a normal operating state by performing calibration work of the gas sensor. It is done.

  The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an outline of a configuration in an example of a combustible gas detection system of the present invention.
The combustible gas detection system 10 is configured such that the test gas is introduced from the drying furnace 11 that forms the test target space S in which the concentration of the combustible gas is to be monitored, and the concentration of the combustible gas contained in the test gas. The gas sampling device 20 for monitoring and the function of controlling the operation of each component constituting the combustible gas detection system 10 and the concentration of the combustible gas exceeds a predetermined value (explosive lower limit concentration) And a control device 30 having a notification function for generating an alarm when the signal is detected. In FIG. 1, reference numeral 12 denotes a main gas introduction path for introducing the test gas into the monitoring gas sampling device 20. The broken lines indicate electrical wirings through which various operation command signals from the control device 30 or gas detection signals from the monitoring gas sampling device 20 and other components are transmitted.

The monitoring gas sampling apparatus 20 includes, for example, a gas detection means 21 configured by a contact combustion type gas sensor, and an aspirator 22 which is a gas suction means for introducing a test gas into the gas detection means 21. It is. The aspirator 22 is operated when compressed air is supplied by an appropriate air supply means (not shown) through an air supply path 23 connected to the aspirator 22.
In the monitoring gas sampling apparatus 20 in this example, a flow rate detection unit 25 is provided in a gas flow path between the gas detection unit 21 and the aspirator 22, and the flow rate detection unit 25 allows the entire gas detection system 10 to flow. By detecting that the excess gas flow rate has decreased, a flow rate decrease signal is output to the control device 30, and the control device 30 turns on the flow rate decrease alarm display lamp 34.

  The control device 30 is provided with an alarm notification mechanism 31 by light emission, for example. Specifically, for example, a gas alarm light emitting unit 32 for notifying that the concentration of the combustible gas contained in the test gas is equal to or higher than a specified concentration (lower explosion limit concentration), and a gas sensor A sensor abnormality notification light emitting unit 33 for notifying that the detection performance inspection is performed and the gas sensor is detected to be active is provided.

  In the combustible gas detection system 10 described above, when the aspirator 22 in the monitoring gas sampling device 20 is operated, the test gas, which is the air in the drying furnace 11, is introduced into the gas detection means 21, and the test gas is in the test gas. When the gas detection means 21 detects that the concentration of the combustible gas contained in the gas is greater than or equal to the specified concentration, the gas alarm light emitting unit 32 in the alarm notification mechanism 31 is activated and an alarm due to light emission is issued.

  Thus, in the combustible gas detection system 10, a detection of the detection performance of the gas sensor (hereinafter also referred to as “regular detection performance inspection”) is periodically performed every predetermined period. However, as mentioned above, there are many cases where the operator is exposed to danger, such as the detection performance of the gas sensor being lowered due to deterioration over time of the gas sensor, etc. From this point of view, it is important that the operator confirms the activated state of the gas sensor before starting the monitoring operation.

  In this combustible gas detection system 10, a gas flow path switching means 40 is provided in the main gas introduction path 12 for introducing the test gas into the monitoring gas sampling device 20, and the detection performance of the gas sensor is improved. A sample gas supply device 50 that supplies a sample gas for inspection used to perform an inspection (hereinafter also referred to as “pre-monitoring operation start inspection”) to the monitoring gas sampling device 20 includes a gas flow path switching unit 40 and It is connected to the main gas introduction path 12 through a branch gas introduction path 41 for inspection connected to the gas flow path switching means 40.

  The gas flow path switching means 40 is composed of, for example, a three-way solenoid valve, and is configured to have one of the gas flow paths of the test gas introduction path 15 and the inspection branch gas introduction path 41 communicating with the internal space of the drying furnace 11. The main gas introduction path 12 is controlled to be switchably connected. Specifically, when a monitoring operation for monitoring the concentration of the combustible gas in the environmental atmosphere in the drying furnace 11 is performed, the test gas introduction path from the drying furnace 11 to the gas flow path switching means 40 is performed. 15 is connected to the main gas introduction path 12, and the inspection branch gas introduction path 41 connected to the sample gas supply device 50 is shut off.

  The sample gas supply device 50 supplies a sample gas generator 51 for supplying an inspection sample gas used for performing an inspection before starting the monitoring operation, and an inspection sample gas from the sample gas generator 51. A gas flow path switching means 55 controlled to switchably connect one of the gas flow paths of the test sample gas supply path 56 and the atmosphere introduction path 57 to the test branch gas introduction path 41; It is.

  The sample gas generator 51 includes a sample gas source 53 formed by impregnating a filler for impregnation with a liquid hydrocarbon that is vaporized to generate a combustible gas, and a sealed container 52 in which the sample gas source 53 is disposed. It is comprised by. The hermetic container 52 has a lid member (not shown) that is detachably provided, so that the sample gas source 53 can be replaced. The internal space of the sealed container 52 is open to the atmosphere via a gas exchange tube member 54.

As the impregnating filler constituting the sample gas source 53, for example, a fibrous material such as paper or cloth, or a porous material is used.
As the liquid hydrocarbon constituting the sample gas source 53, for example, ethyl alcohol, methyl alcohol, or the like is used.
In the sample gas source 53, the content ratio of the liquid hydrocarbon to the filler for impregnation is such that when, for example, ethyl alcohol is used as the liquid hydrocarbon, the concentration of the combustible gas generated in the sealed container 52 is 19 ° C. The size is sometimes 5.4% by volume.

The gas flow path switching means 55 is composed of, for example, a three-way solenoid valve, and connects the test sample gas supply path 56 to the main gas introduction path 12 for a fixed time, for example, 15 seconds, and then shuts off the test sample gas supply path 56. Then, the air introduction passage 57 is operated to connect to the main gas introduction passage 12 for a certain period of time, for example, 45 seconds.
The gas flow path switching operation by the gas flow path switching means 55 is performed in conjunction with, for example, the gas flow path switching operation by the gas flow path switching means 40 provided in the main gas introduction path 12.

In the combustible gas detection system 10, the inspection before starting the monitoring operation for the gas sensor is performed as follows.
That is, the opening / closing operation of the gas flow path switching means 40 provided in the main gas introduction path 12 is controlled by the control device 30, and the inspection branch gas introduction path 41 connected to the sample gas supply apparatus 50 is the main gas introduction path. 12, the opening / closing operation of the gas flow path switching means 55 in the sample gas supply device 50 is controlled in conjunction with the opening / closing operation of the gas flow path switching means 40, and the test sample gas supply path 56 is branched. Connected to the gas introduction path 41. Here, the test gas introduction path 15 communicated with the internal space of the drying furnace 11 is cut off from the main gas introduction path 12, and is opened to the atmosphere in the sample gas supply apparatus 50. The air introduction path 57 is in a state of being blocked from the inspection branch gas introduction path 41.

  Then, the compressed air is introduced into the aspirator 22 in a state where the flow rate is adjusted to an appropriate size, whereby the aspirator 22 is actuated, whereby the inspection sample gas is introduced into the gas detection means 21. Specifically, the sample gas for inspection generated by vaporizing liquid hydrocarbons in the sealed container 52 is sucked by the aspirator 22 and supplied to the gas detection means 21 for a predetermined time (for example, 15 seconds). Thereafter, the opening and closing operation of the gas flow path switching means 55 in the sample gas supply device 50 is controlled to switch the gas flow path, and the test sample gas supply path 56 is shut off from the test branch gas introduction path 41. At the same time, the atmosphere introduction path 57 is connected and sucked by the aspirator 22 so that the atmosphere is supplied for a certain time (for example, 45 seconds).

  Then, the sample gas for inspection is detected by the gas detection means 21, and it is detected that the gas sensor is detected to be higher than the dangerous concentration value at the time of the detection performance inspection of the gas sensor, that is, the gas sensor is in an active state. As a result, an operation command signal for the alarm notification mechanism 31 is output by the control device 30, and an alarm due to light emission is issued by the sensor abnormality notification light emitting unit 33. On the other hand, when there is an abnormality in the gas sensor that constitutes the gas detection means 21, the alarm notification mechanism 31 is not activated, and thus the operator can recognize that the required gas sensor calibration process is necessary. it can. Here, the dangerous concentration value at the time of the inspection before starting the monitoring operation is set to a concentration value lower than the dangerous concentration value at the time of the monitoring operation (25% of explosion lower limit concentration value: 25% LEL), for example, 20% LEL. Is done.

Thereafter, the atmosphere introduction path 57 is blocked from the inspection branch gas introduction path 41 and the operation of the aspirator 22 is stopped.
In the above, the time required for the inspection before the monitoring operation is, for example, about 3 minutes.

According to the combustible gas detection system 10 having the above-described configuration, a sample gas that is less expensive as the sample gas generation source 51 than the standard gas for inspection used in the regular detection performance inspection that is periodically performed. The supply device 50 is provided, and the inspection sample gas is supplied for a very short time and the inspection before the monitoring operation is performed, so that the time required for the inspection can be shortened and the gas detection means can be realized at a low inspection cost. The required inspection can be performed on the gas sensor constituting 21.
Therefore, before starting the monitoring operation, the operator can recognize whether or not the gas sensor is in an active state, and the gas sensor is always in a normal state by performing calibration processing of the gas sensor as necessary. As a result, it is possible to configure the combustible gas detection system 10 as having high safety without exposing the worker to danger due to malfunction of the gas sensor or the like.

  In the inspection before starting the monitoring operation of the gas sensor, the dangerous concentration value to which a gas alarm signal should be output is set lower than the dangerous concentration value at the time of the monitoring operation, but it has the desired responsiveness to combustible gas. It is only necessary to know whether or not the gas sensor is in an active state, and since rigorous calibration of the gas sensor is performed in regular detection performance inspection that is performed regularly, There is no problem.

As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment, A various change can be added.
For example, the gas suction means is not limited to one constituted by an aspirator, and can be constituted by, for example, a suction pump.
In addition, the sample gas supply device is configured to supply a mixed gas of combustible gas and other gas from a sample gas generator as an inspection sample gas, and to perform an active state inspection on a plurality of gas sensors. It may be.
Further, when the inspection before the monitoring operation is performed, the time when the sample gas supply device is operated, specifically, for example, the supply time of the sample gas and the atmospheric supply time are supplied to the length of the main gas introduction path and the gas detection means. It can be set appropriately according to conditions such as the gas flow rate.

It is a block diagram which shows the outline of a structure in an example of the combustible gas detection system of this invention. It is a block diagram which shows the outline of a structure in an example of the conventional combustible gas detection system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Combustible gas detection system 11 Drying furnace 12 Main gas introduction path 15 Test gas introduction path 20 Monitoring gas sampling device 21 Gas detection means 22 Aspirator 23 Air supply path 25 Flow rate detection means 30 Control apparatus 31 Alarm notification mechanism 32 Gas alarm Light emitting part 33 Light emitting part for sensor abnormality notification 34 Low flow alarm display lamp 40 Gas flow path switching means 41 Branch gas introduction path for inspection 50 Sample gas supply device 51 Sample gas generator 52 Sealed container 53 Sample gas source 54 For gas replacement Pipe member 55 Gas flow path switching means 56 Sample gas supply path for inspection 57 Air introduction path 60 Combustible gas detection system 61 Monitoring gas sampling device 62 Gas detection means 63 Gas suction means 65 Control device 66 Main gas introduction path 67 Standard gas Supply path 70 Standard gas supply Location 71 cylinder S inspected space

Claims (6)

A sample gas supply device for supplying a sample gas for inspection used when inspecting the detection performance of a gas sensor for detecting a combustible gas,
A sample gas supply comprising a sample gas generator in which a sample gas source formed by impregnating a filler for impregnation with a liquid hydrocarbon that evaporates to generate a combustible gas is disposed in a sealed container apparatus.   2. The sample gas supply device according to claim 1, wherein ethyl alcohol or methyl alcohol is used as the liquid hydrocarbon constituting the sample gas source.   The sample gas supply device according to claim 1 or 2, wherein the sealed container is configured such that a sample gas source is replaceable. Gas sampling device for monitoring provided with a gas detection unit for detecting flammable gas, gas suction means for introducing a sample gas or a sampling gas for inspection into the gas detection unit, and a detection result by the gas detection unit For the inspection used when performing the detection performance inspection of the gas detection unit that is performed at any time separately from the alarm notification mechanism that issues an alarm based on the gas detection unit and the detection performance inspection of the gas detection unit that is periodically performed every predetermined period A sample gas supply device for supplying the sample gas,
A combustible gas detection system, wherein the sample gas supply device comprises the apparatus according to any one of claims 1 to 3.   In the detection performance inspection of the gas detection unit performed at any time, an alarm by the alarm notification mechanism is detected when the gas detection unit detects that the concentration of the sampling gas for inspection supplied to the gas detection unit is a predetermined value or more. The combustible gas detection system according to claim 4, wherein the combustible gas detection system is emitted.   5. The dangerous gas concentration value that triggers an alarm when the detection performance inspection of the gas detector is performed is set lower than the dangerous gas concentration value that triggers an alarm during a monitoring operation. Or the combustible gas detection system of Claim 5.

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