JP2000227408A - Gas detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow an operation with high reliability irrespective of a votage drop in a power cable. SOLUTION: This detector is provided with the first and second connctors 5, 6 connected to a commercial alternating current power cable and connected in parallel each other, a switching power source unit 12 receiving electric power from the first connector 5, a sampling pump 22 communicated with a chamber 21 for storing a gas sensor S, and a transmission unit 15 for converting a signal from the gas sensor S into a transmissible signal to be output to the first connector 5. Electric power having a voltage close to a specified voltage as much as possible is suplied to the sampling pump 22 by the power source unit 12, irrespective of voltages supplied to the connectors 5, 6. The electric power having the voltage close to the specified voltage as much as possible is supplied from the power source unit 12 even in a voltage drop in the power cable to keep a sampling amount, and sample gas is surely detected thereby.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas detector having a function of transmitting a measurement signal to a remote monitoring device by using a power supply cable for a communication line.

[0002]

2. Description of the Related Art In a plant or the like, a large number of gas detectors are arranged in order to quickly detect a gas leak leading to a major accident, and a detection signal is transmitted to a monitoring device for centralized management. On the other hand, the gas detection device is configured such that, in addition to the gas detection means, a sampling pump and a signal transmission means for positively taking in the air in the region to be detected into the gas detection means are housed in a case. Then, power is received from a power supply unit of the monitoring device by a power line cable, and a measurement signal is transmitted to the monitoring device by a power line carrier method using the power line cable for a communication line.

[0003]

As a result, it is not necessary to provide a communication line and the equipment cost can be reduced. However, the gas detector far from the monitoring device has a large voltage drop due to the electric resistance of the power cable. Therefore, there is a problem in that the gas sampling amount of a sampling pump requiring particularly large electric power varies among the apparatuses, and the reliability of measurement decreases. The present invention has been made in view of such a problem, and an object of the present invention is to provide a gas detection device capable of detecting a test gas with high reliability regardless of the distance of a power line cable. That is.

[0004]

In order to achieve the above object, according to the present invention, there are provided first and second connectors connected to a commercial AC power cable and connected in parallel with each other. A switching power supply unit that receives power supply, a sampling pump that communicates with a chamber containing a gas sensor, and a transmission unit that converts a signal from the gas sensor into a transportable signal and outputs the signal to a first connector. .

[0005]

[Operation] Since the switching power supply unit outputs DC power of a voltage as close as possible to the specified voltage as much as possible due to the voltage drop in the power line cable, drive the sampling pump at a rated rate to maintain a constant sampling amount. Can be.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a first embodiment of the present invention. FIG. 1 shows an embodiment of the present invention. An apparatus 1 includes a main unit 1 in a case including a flameproof container 2a and a lid 2b.
0, switching power supply unit 12, adjustment unit 1
4, housing the inverter unit 18 and the detection unit 20, connection ports 3 and 4 communicating with the detection unit 20 are provided on the side of the main body 2a, and connectors 5 and 6 connecting to the power cable are provided at the lower part. I have. The cover 2b is provided with a lever 7 connected to the power switch SW and a window 8 for operating the adjustment unit 14 housed in the main body 1.

FIG. 2 is a block diagram showing an embodiment of the gas detecting device according to the present invention. The main unit 10 is supplied with commercial AC power from the connector 5 and is connected to a lead wire 11 via a conductive pattern (not shown). AC power is supplied to a switching power supply unit 12 to be described later connected thereto, and DC power for operation is supplied from the switching power supply 12 via a cable 13.

The main unit 10 has an adjusting unit 14 which is externally operated through the above-mentioned window 8 and a transmission unit 1.
5 is connected.

The switching power supply 12 has an output terminal 1
6 has an inverter unit 17 in addition to the main unit 10.
Are connected via a cable 18. The inverter unit 18 is connected to the detection unit 20 via a cable 19.
And supplies AC power to a sampling pump 22 that can be AC driven and communicates with a chamber 21 containing a gas sensor S. By using a sampling pump for AC driving as described above, reliability can be ensured and cost can be reduced.

[0010] Gas sensor S housed in chamber 21
Receives driving DC power from the main unit 10 via a cable 23, outputs a measurement signal to the main unit 10 via a cable 24, is converted by the transmission unit 15 into a signal capable of carrying power lines, and , 6
Is output to

Reference numeral 25 in FIG.
To the main unit 1
It shows an insulated amplification unit that outputs 0.

In this embodiment, as shown in FIG. 3, the first connector 5 of the first detecting device 1 is connected to the power line cable 31 connected to the insulated power supply unit 32 of the central monitoring device 30, and a two-core wire is provided. A required number of detectors 1 are connected to the connector 5 by connecting one end of the cable 32 'to the second connector 6 of the first detector 1 and the other end to the first connector 5 of the second detector 1'. , 6, cables 32, 3
2 ', 32 "to connect in series.

When the power switches SW of the detection devices 1 and 1 'are turned on in a state where the plurality of detection devices 1 are connected as described above, AC power is supplied to the switching power supply unit 12, and a specified voltage, for example, a DC voltage of 12V Electric power is supplied to the inverter unit 17 and the main unit 10. The inverter unit 17 converts the supplied DC power into a predetermined voltage, for example, 100 V alternating power, and supplies it to the sampling pump 22 of the detection unit 20.

By the operation of the sampling pump 22, air in the environment to be measured is taken into the chamber 21 from the connection port 3 and discharged from the connection port 4 to the outside. The gas sensor S outputs a measurement signal corresponding to the measured component contained in the taken air to the transmission unit 15 via the main unit 10. The transmission signal generated by the transmission unit 15 is output to the cable 32 via the connector 5 and transmitted to the central monitoring device 30.

By the way, in the detection device 1 installed far away from the central monitoring device 30, although the voltage drop due to the power line cable becomes large, the switching power supply unit 12 outputs the DC power of the specified voltage, and particularly large. The power of the specified voltage is also supplied to the detection unit 20 that consumes power, and the operation in the rated state is guaranteed.

In the above-mentioned embodiment, the DC power from the switching power supply unit 12 is converted into the alternating power by the inverter unit to operate the sampling pump. Is used, it can be driven by DC power of a specified voltage from the switching power supply unit.

Further, in the above-described embodiment, the gas detecting device is configured as a gas detecting device containing a detecting unit. However, a signal from another separately detecting unit is received by a transmission cable, and a measuring signal is transmitted to a central monitoring device. Can also be used as a transmission device for transmitting by power transmission.

[0018]

As described above, according to the present invention, first and second connectors connected to a commercial AC power cable and connected in parallel with each other, and a switching power supply receiving power supply from the first connector Unit, a sampling pump that communicates with the chamber containing the gas sensor, and a transmission unit that converts the signal from the gas sensor into a transportable signal and outputs the signal to the first connector. Accordingly, the switching power supply unit supplies electric power having a voltage as close as possible to the specified voltage to the sampling pump to keep the sampling amount constant, thereby reliably detecting the test gas.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a gas detection device of the present invention.

FIG. 2 is a block diagram showing one embodiment of the gas detection device of the present invention.

FIG. 3 is a block diagram showing a usage form of the gas detection device.

[Explanation of symbols]

 3, 4 Connection port 5, 6 First and second connectors for power cable connection 10 Main unit 12 Switching power supply unit 18 Inverter unit 20 Detection unit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G08B 25/06 G08B 25/06 H04Q 9/00 311 H04Q 9/00 311S (72) Inventor Toshio Kumazawa Chiba 25, Shintomi, Futtsu-shi Tokyo Electric Power Company Futtsu Thermal Power Plant (72) Inventor Yuji Hirayama 2-7-6 Shozuzawa, Itabashi-ku, Tokyo Inside RIKEN Keiki Co., Ltd. 7-7-6 F-term in RIKEN KEIKI Co., Ltd. (reference) 2G060 AA01 AE11 AE19 HC01 HE05 2G067 BB11 CC04 DD17 DD18 EE13 5C086 AA02 BA20 CB11 DA08 EA07 5C087 AA02 BB07 DD07 EE08 FF04 FF10 GG83 GG66GG 06048

Claims (2)

[Claims] 1. A first power supply unit connected to a commercial AC power cable and connected in parallel with each other, a switching power supply unit receiving power supply from the first connector, and a chamber accommodating a gas sensor. And a transmission unit that converts a signal from the gas sensor into a transportable signal and outputs the signal to a first connector. 2. The gas detection device according to claim 1, wherein an inverter unit is connected to an output terminal of the switching power supply unit, and the sampling unit receives drive power from the inverter unit.