JP2004069377A - Gas concentration detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable only various kinds of gas sensors to be replaced easily and instantly or adjusted, when the gas sensors reach their life's end, to reduce entire costs, and to constantly show reliable and accurate detection functions. <P>SOLUTION: A sensor head 3 and a detector body section 5 can be attached or detached physically via screwing of a nut-like member 6 and a cylindrical external thread section 7, and can be connected or separated electrically via lead-wire-type connectors 10, 12. Additionally, the functions for transmitting and receiving a signal for identifying the type of sensors and a signal for verifying connection are provided between both of them 3, 5. In this case, the sensor head 3 comprises an EO gas sensor 13 for detecting an EO gas, an accumulator 14 for drive, and an output circuit 15. The detector body section 5 comprises a CPU 16 for performing concentration conversion of the gas detection signal; an LCD 18 for displaying gas concentration by numeric values; an accumulator 19 for driving them; and an operation section. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a gas concentration detector. Specifically, in order to sterilize medical instruments, clothes, bedding, and the like using ethylene oxide gas (hereinafter referred to as EO gas), the waste gas discharged from an EO gas sterilizer installed mainly in medical institutions and the like is used. The present invention relates to a gas concentration detector typified by an EO gas concentration detector that measures the concentration of harmful EO gas.
[0002]
[Prior art]
This type of gas concentration detector calculates the gas detection signal from the gas sensor and converts it into a gas concentration, displays the calculated gas concentration, or outputs an alarm when the gas concentration exceeds a set value. The conventional general gas concentration detector includes a gas sensor unit that detects gas, a calculation unit that converts the detection signal into a gas concentration, a driving power supply, an operation unit, and the like. The main body was configured as a single-piece detector integrally incorporated in a single exterior case.
[0003]
[Problems to be solved by the invention]
In general, in a gas concentration detector, a gas sensor, which is the most important element in determining the quality of a predetermined detection performance among many components, has a shorter life than other components and is used after a certain period of use. In order to restore the concentration sensor whose gas sensor has reached the end of its service life to the initial detection performance, replace the entire concentration sensor, or remove and replace only the gas sensor from the main unit, or readjust it. Is required.
[0004]
However, as in the conventional case, in a gas concentration detector configured as a single unit, if the entire sensor is replaced because the gas sensor has reached the end of its life, economic loss is very large. Also, when removing and replacing only the gas sensor, or when re-adjusting it, removing and re-assembling the gas sensor incorporated in the outer case requires not only a very large and troublesome task but also replacement and re-adjustment. Until the detection is completed, the detector itself cannot be used.If gas concentration detection is required during that time, the gas concentration must be continuously measured, such as using a separately prepared same type of concentration detector. In order to perform the detection, it is necessary to prepare at least two detectors and use them alternately, and there is a problem that the cost increases accordingly.
[0005]
In addition, multiple types of gas sensors have been developed to respond to various usage conditions and usage environments.However, a conventional single gas concentration detector has a concentration display function and an alarm output function. Despite being the same, it is not possible to exchange and use only the type of gas sensor according to the use conditions, use environment, and the like. Therefore, even when the same gas is to be detected, it is necessary to manufacture and prepare a plurality of types of detectors separately for each type of gas sensor and selectively use them according to the use conditions, etc. There was also a problem that it was easy to rise.
[0006]
The present invention has been made in view of the above circumstances, and when a gas sensor reaches the end of its life, it is possible not only to easily and immediately replace or readjust the gas sensor, but also to use different types of gas sensors. Another object of the present invention is to provide a gas concentration detector which can be easily replaced, can reduce the total cost, and can always reliably exhibit a predetermined detection performance.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a gas concentration detector according to the present invention includes a gas sensor for detecting gas, a sensor driving power source, and a sensor head unit including a gas detection signal output circuit by the gas sensor. A calculation unit for calculating a gas detection signal output from the output circuit to convert the gas concentration into a gas concentration, a display unit for numerically displaying the calculated gas concentration, a detector main body unit having a power supply for driving them and an operation unit are included. A gas concentration detector which is physically detachable and electrically connectable and detachable, wherein both are electrically connected between the sensor head portion and the detector main body portion. When it is performed, a signal transmission means for transmitting the identification signal of the gas sensor type and the connection confirmation signal provided to the sensor head portion side to the detector body portion side is provided, and the detector body portion side A means is provided for switching to an operation state corresponding to the type of gas sensor in response to reception of the identification signal, and for permitting start of operation in response to reception of the connection confirmation signal. .
[0008]
According to the present invention having the above structure, when the gas sensor reaches the end of its life, the sensor head including the gas sensor is detached from the main body of the detector, so that only the gas sensor can be easily or quickly replaced or re-used with very little trouble. It is possible to adjust and restore the original detection performance in a short time, so that one concentration detector can be used for almost continuous gas concentration detection Compared to this, it can be used simply and economically, and the cost required for continuous gas concentration detection can be reduced.
[0009]
In addition, when the sensor head and the detector main body are electrically connected, a gas sensor type identification signal and a connection confirmation signal are transmitted from the sensor head to the detector main body. As the signal is received, the operation state on the detector main body side is switched to the one corresponding to the gas sensor type, and the arithmetic operation in the switched state is started. It is possible to easily replace and use only different types of gas sensors according to the usage conditions and usage environment of the detector while using the components on the side as they are, While reducing the number of types of detectors required to meet the requirements and reducing the overall cost, always ensure that the specified detection function is always exhibited when using any type of gas sensor Possible it is.
[0010]
In the gas concentration detector having the above configuration, as a detachable structure of the sensor head portion and the detector main body portion, as described in claim 2, the gas concentration detector is rotatably held only in the outer cylindrical case on the sensor head portion side. In addition to being physically detachable via a threaded connection between a nut-shaped member and a cylindrical external thread portion formed integrally with the exterior case head on the detector main body side, the signal transmission means is also included. By adopting a detachable structure that can be electrically connected and separated via a lead wire type connector, both can be easily attached and detached by simple operations such as connecting or disconnecting the connector and rotating the nut-shaped member. In addition, a predetermined detection performance can always be ensured without causing a defect such as twisting of the lead wire.
[0011]
Further, in the gas concentration detector having the above configuration, as described in claim 3, by providing a high concentration gas alarm means for outputting an alarm when the gas concentration becomes equal to or higher than a set value in the detector main body. , It is possible to immediately know that the gas concentration has exceeded the allowable set value.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an external front view of an entire EO gas concentration detector which is an example of a gas concentration detector according to the present invention, and FIG. 2 is an enlarged partial cutaway front view of a main part. The sensor head section 3 having the outer cylindrical case 2 and the detector main body section 5 having the flat box-shaped outer case 4 are rotatable only to the outer cylindrical case 2 on the sensor head 3 side. It is physically detachable via a screw connection between a nut-like member 6 held and fitted to the outside and a cylindrical male screw part 7 integrally formed on the head of the exterior case 4 on the detector main body 5 side. A female connector 10 connected to a circuit board 8 on the sensor head 3 side via a lead wire 9 and a male connector 12 fixedly connected to a circuit board 11 on the detector main body 5 side. Can be electrically connected and disconnected, including the signal transmission means described later. It has been made.
[0013]
FIG. 3 is a circuit block diagram of the EO gas concentration detector 1. The sensor head unit 3 includes an electrochemical gas sensor 13 that generates an electromotive force in EO gas, and a manganese lithium lithium battery (DC3V) as a power supply for driving the sensor. An output circuit 15 which comprises a constant voltage circuit 15A, a buffer circuit 15B, an IV conversion circuit 15C, and an operation amplifier circuit 15D formed on the substrate 8 and outputs a DC voltage which is an EO gas detection signal by the gas sensor 13. , A sensor type identification signal transmitting unit 29 and a connection confirmation signal transmitting unit 30 which are provided in advance in accordance with the type of the gas sensor 13 are provided.
[0014]
On the other hand, the detector main body unit 5 includes a CPU 16 for calculating a DC voltage output from the output circuit 15 of the sensor head unit 3 to convert the DC voltage to an EO gas concentration, and a driver 17 for calculating the EO gas concentration calculated by the CPU 16. An LCD (display unit) 18 that displays numerical values on the surface of the exterior case 4 via a battery, a lithium ion storage battery 19 as a power supply for driving them, a charging circuit 21 having a DC jack 20, a power on / off switch 22, An operation section comprising a switch 23 for displaying and displaying a peak value and a real value of the EO gas concentration, and outputting an intermittent sound as an alarm when the EO gas concentration exceeds a high concentration value set in the E ² PROM 24. Buzzer 25, the state of switching between the display of the peak value and the real value, the state of charging, and the exterior when the EO gas concentration exceeds the set value. Three LED26A that lights or blinks display on the surface of the case 4, 26B, and the 26C is equipped is formed on the circuit board 11.
[0015]
The CPU 16 of the detector main unit 5 receives and determines the sensor type identification signal transmitted from the transmitting unit 29 of the sensor head unit 3 and switches to a calculation operation state corresponding to the gas sensor type. It has a function of receiving and confirming the connection confirmation signal transmitted from the unit 30, and allowing the start of the arithmetic operation.
[0016]
The ON / OFF switch 22 and the display changeover switch 23 are configured as a membrane sheet switch 27, and the three LEDs 26A, 26B, and 26C are mounted on the membrane sheet switch 27. The CPU 16 is connected to a thermistor 28 that is built in the detector main body 5 and corrects the temperature of the output from the sensor head 3. Further, when the remaining battery power of the storage batteries 14 and 19 becomes 10% or less, the LCD 18 is configured to display “−−−−” so as to prompt charging.
[0017]
In the EO gas concentration detector 1 having the above configuration, when the on / off switch 22 is long-pressed for about 2 seconds to switch on, the high concentration value set in the E2 PROM 24 is displayed on the LCD 18 three times per second. After the blinking display, the LCD 18 goes blank for about 2 seconds, and from this state, the warm-up time is counted down from 10 → 9 →... → 1 for 10 seconds, and then the normal measurement (detection) operation is started.
[0018]
In this normal measurement operation, the gas sensor 13 placed in the EO gas atmosphere generates an electromotive force, and the DC voltage output from the output circuit 15 of the sensor head unit 3 is calculated by the CPU 16 of the detector main body 5 and the EO voltage is calculated. It is converted to gas concentration. The converted EO gas concentration is numerically displayed on the LCD 18 via the driver 17. At this time, the display changeover switch 23 is normally in the real value display mode, and the current actually measured EO gas concentration value is displayed. However, by switching the display changeover switch 23 as necessary, The measured peak value can be numerically displayed on the LCD 18.
[0019]
If the value of the EO gas concentration becomes equal to or higher than the high concentration value set in the E ² PROM 24 during the above measurement, the LED 26A flashes and the buzzer 25 operates (sounds) at the same time as the output from the CPU 16. As a result, an intermittent sound as an alarm is output.
[0020]
In the EO gas concentration detector 1 that operates as described above, when the gas sensor 13 has reached the end of its life, the nut-shaped nut that is fitted and held on the exterior cylindrical case 2 on the sensor head 3 side including the gas sensor 13. By rotating the member 6, the nut-shaped member 6 is unscrewed from the cylindrical male screw portion 7 of the head of the exterior case 4 on the detector main body 5 side, and the lead is connected to the circuit board 8 on the sensor head portion 3 side. By pulling out and separating the female connector 10 connected via the wire 9 from the female connector 12 fixedly connected to the circuit board 11 on the detector main body 5 side, the sensor head 3 is separated from the detector main body 5. It is possible to physically and electrically separate.
[0021]
In the physically and electrically separated state of the sensor head unit 3 and the detector main body unit 5, only the gas sensor 13 is replaced, or after the gas sensor 13 is readjusted, the female and male connectors 12 and 10 are inserted and connected. The nut-like member 6 is screwed and fastened to the male screw portion 7 to physically join and electrically connect the two 3 and 5, and to confirm the state of the electrical connection to allow the start of the operation. Thus, the EO gas concentration detector 1 can be restored to the original detection performance in a short time. As a result, one detector 1 can be used for substantially continuous gas concentration detection, and can be used more easily and economically than conventional single-unit detectors, and the cost required for continuous gas concentration detection can be reduced. I can do it.
[0022]
In the same manner as described above, with the sensor head 3 and the detector main body 5 physically and electrically separated from each other, the gas sensor 13 is replaced with a different one, and then the female and male connectors 12 and 10 are replaced. When the nuts 6 and the nuts 6 are screwed and fastened to the male screw portion 7 to physically connect and electrically connect the nuts 3 and 5, the transmitting portions 29 and 30 on the sensor head 3 side. , A sensor type identification signal and a connection confirmation signal are transmitted to the CPU 16, and based on the determination of the gas sensor type by the CPU 16 having received these signals, the operation mode is switched to an arithmetic operation state corresponding to the gas sensor type, and the connection confirmation signal is received. The start of the calculation operation of the CPU 16 is allowed by the confirmation, and the EO gas concentration detector 1 is brought into a state in which the detection performance corresponding to the gas sensor type is exhibited within a short time. It is possible to the original.
[0023]
Note that, in the above-described embodiment, the case where the detection target gas is EO gas has been described, but the same applies to a gas concentration detector used for detecting the concentration of other gases, particularly harmful gases such as CO. It is possible to achieve the effect.
[0024]
【The invention's effect】
As described above, according to the present invention, when the gas sensor has reached the end of its life, the sensor head having the gas sensor is detached from the detector main body having the gas concentration display section, etc. Easy and quick replacement or readjustment with a very small number of steps allows restoration of the original detection performance in a short period of time. Can be used for detection. In addition, when the gas sensor of the sensor head is replaced with a different type of gas sensor, a signal for identifying the type of gas sensor is transmitted from the sensor head to the detector main body, and the detector main body receives a signal according to the signal. Since the operation state can be switched to the one corresponding to the gas sensor type, it is possible to easily and arbitrarily and easily use multiple types of gas sensors corresponding to the use conditions and use environment while using the components on the detector main body as it is. The detector can be replaced and used, and accordingly, the number of types of detectors required for adapting to use conditions and use environments can be reduced, and overall cost can be reduced. In addition, after replacing or re-adjusting the gas sensor, or when replacing it with any type of gas sensor, the arithmetic operation does not start unless the electrical connection between the sensor head and the detector main body is confirmed. In addition, an effect is provided that an accurate detection function can be exhibited.
[0025]
In particular, as a detachable structure of the sensor head portion and the detector main body portion, the nut-shaped member and the detector which are rotatably held by the outer cylindrical case on the sensor head portion side only as described in claim 2. It is physically detachable through screwing with a cylindrical male screw part formed integrally with the exterior case head on the body side, and through a lead wire type connector including signal transmission means. By adopting the detachable structure that is configured to be electrically connectable and detachable, both can be easily attached and detached by simple operation such as connecting or disconnecting the connector and rotating the nut-shaped member, and replacing and re-adjusting the gas sensor. Furthermore, even after replacement of the gas sensor type, a predetermined detection performance can be always ensured without causing a failure such as twisting of the lead wire.
[Brief description of the drawings]
FIG. 1 is an external front view of an entire EO gas concentration detector which is an example of a gas concentration detector according to the present invention.
FIG. 2 is an enlarged partial cutaway front view of a main part of the EO gas concentration detector.
FIG. 3 is a circuit block diagram of the EO gas concentration detector.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 EO gas concentration detector 2 Exterior cylindrical case 3 Sensor head 4 Exterior case 5 Detector main body 6 Nut-shaped member 7 Cylindrical male screw 9 Lead wire 10 Female connector 12 Male connector 13 Electrochemical gas sensor 14 Manganese lithium battery (power supply for driving sensor)
15 output circuit 16 CPU (arithmetic unit)
18 LCD (display unit)
19 Lithium ion storage battery (power supply for driving arithmetic and display units)
25 Buzzer (High concentration gas alarm means)
29 Gas sensor type identification signal transmitter 30 Connection confirmation signal transmitter

Claims (3)

A gas sensor for detecting gas, a sensor driving power supply, and a sensor head unit including a gas detection signal output circuit by the gas sensor, and a gas detection signal output from the output circuit of the sensor head unit are calculated and converted into a gas concentration. An arithmetic unit, a display unit for numerically displaying the calculated gas concentration, and a detector main unit equipped with a drive power supply and an operation unit for them are physically detachable and electrically connectable and disconnectable. Gas concentration detector,
When both are electrically connected between the sensor head section and the detector main body section, a gas sensor type identification signal and a connection confirmation signal provided to the sensor head section side are supplied to the detector main body section. A signal transmission means for transmitting is provided on the side, and the detector main body side is switched to an arithmetic operation state corresponding to the type of gas sensor in accordance with the reception of the identification signal, and in accordance with the reception of the connection confirmation signal. A gas concentration detector comprising means for permitting the start of a calculation operation. The sensor head portion and the detector main body are integrally formed with a nut-like member rotatably held in the outer cylindrical case on the sensor head portion side and the outer case head on the detector main body side. It is configured so that it can be physically attached and detached via screwing with a cylindrical male screw part, and can be electrically connected and separated via a lead wire type connector including the signal transmission means. The gas concentration detector according to claim 1, wherein 3. The gas concentration detector according to claim 1, wherein the detector main body is provided with a high concentration gas alarm unit that outputs an alarm when the gas concentration becomes equal to or higher than a set value.

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