JPS5812126Y2 - gas detection alarm - Google Patents

Description

[Detailed description of the invention] The present invention relates to a gas detection alarm, and particularly to a gas detection alarm that can always maintain a normal state by adjusting the outputs of the transmitting part and the receiving part of the gas detection alarm to standardized values. be.

An example of implementing the present invention will be described below with reference to the drawings.

Generally, gas detection alarms are installed as a way to prevent gas explosion accidents, but it is most important that these gas detection alarms are always operating normally.

As shown in FIG. 1, a conventional alarm has a Wheatstone bridge circuit 2 which includes a gas detection element 1. : Consisting of a transmitter 3 that has a transmitter 3, and a receiver 4 that receives this output, instructs the gas concentration and issues an alarm.The transmitter 3 is installed in or around a dangerous place where gas accumulates or is The transmitting section 4 is placed in a control room or the like in a non-hazardous place where it can be monitored on a daily basis, and is used by connecting it with a cable 5, and the transmitting section 3 is required to have sufficient explosion-proof performance.

In such a configuration, the zero adjustment and calibration circuit for the gas detection alarm is usually provided in the receiving section 4, and when adjusting the device, for example, fresh air is supplied to the transmitting section for a zero adjustment test. If it is inserted, the receiving unit will not be able to tell at this point.

The same applies to the case where a known gas is introduced into the transmitting section and the meter of the receiving section is adjusted.

For this reason, a coordinator is assigned to each of the transmitting section 3 and the receiving section 4, and coordination is carried out while maintaining close communication.

For example, as a means of communication during this time, transceiver 1
ζ In recent years, as factories have expanded in size and their facilities have become more sophisticated, the use of transceivers has become a cause of malfunctions in other instruments, so The number of factories whose use is prohibited is increasing, and in many cases it is difficult to use facilities such as telephones depending on the location.In such cases, a liaison officer was also appointed to coordinate during this time.

Furthermore, in the conventional method, the transmitting section 3 and the receiving section 4 have to be adjusted as a pair, which results in poor compatibility with each other, requiring a lot of labor and time, and making accurate adjustment difficult.

The present invention compensates for these shortcomings, and makes it possible to make the transmitting part and receiving signal compatible while maintaining sufficient explosion-proof performance. It is designed to be easily performed by humans.

In the present invention, as shown in FIG. 2, the transmitter 3 is connected to a Wheatstone bridge circuit 2 including a gas detection element 1, and the output of the Wheatstone bridge is set to zero when the gas detection element 1 does not detect gas. Calibration consists of a zero adjustment circuit 6 to be set and a variable resistor inserted between the output terminals of the Wheatstone bridge so that the output value of the Wheatstone bridge becomes the desired value when the detection element 1 detects a gas with a predetermined concentration. It consists of a circuit 7 and an electrical energy limiting circuit 8.

The inquiry transmitter 3 is housed in an explosion-proof container 9, and the zero adjustment circuit 6 and the calibration circuit 7 can be adjusted from outside the pressure-resistant explosion-proof container 9.

Further, the container 9 is provided with a connection port 10, and a regulating device 11 provided outside the container 9 is connected to the bridge circuit 2 via the connection port 10 and the electric energy limiting circuit 8.

The electric energy limiting circuit 8 controls the output applied from the transmitter 3 to the connection port 10, and makes the spark generated by the electric energy generated by this output strong enough to prevent it from igniting the gas. It is a circuit that limits the current or voltage or both current and voltage to below a predetermined value, and the electric current is constant depending on design conditions such as input value setting conditions and environmental conditions for explosion protection. An electrical energy limiting circuit with an appropriate structure may be adopted depending on the energy value.

This is constructed using, for example, a resistor, an energy diode, etc.

The adjustment device 11 includes an amplifier, a meter, a battery, a resistor, etc., and is itself of an intrinsically safe explosion-proof structure.

Since the alarm of the present invention has the above-mentioned configuration, when making adjustments such as zero adjustment and calibration of the transmitter 3 installed in and around the dangerous area, connect the adjustment device 11 to the connection port 10 and adjust the transmitter 3. The gas detection element 1 in the section 3 is brought into contact with fresh air and a gas of a known concentration, and the zero adjustment circuit 6 and the calibration circuit 7 are adjusted so that the readings on the meter of the adjustment device 11 match the respective values. .

This adjustment can be performed very easily since the adjustment device 11 and the transmitting section 3 are close to each other, and since the adjustment device 11 does not need to be of a pressure-resistant and explosion-proof structure, the device has the advantage of being compact, making it safe and requiring only a small amount of Adjustments can be made with effort and time.

In particular, if many transmitting units are installed in faraway places, by always having two or three adjustment devices 11 on hand, you can make adjustments in parallel, and the work that would previously take several days can be completed in a blink of an eye. It is also possible to do so.

Furthermore, the compatibility of the transmitting part 3 and the receiving part 4 makes it possible to immediately replace it with a well-maintained spare part when repairing or replacing equipment, which is especially important for routine maintenance. Considering that certain gas detection elements need to be maintained on a daily basis so that they are always maintained and in good condition and can be replaced immediately in the event of an abnormality,
The effectiveness of the present invention is extremely high, and reliable adjustment can be easily performed, making it safe and economical.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional gas detection alarm, and FIG. 2 is an explanatory diagram of a gas detection alarm of the present invention. 1... Gas detection element, 2... Bridge circuit, 3...
- Transmitting section, 4... Receiving section, 5... Cable, 6...
・Zero adjustment circuit, 7... Calibration circuit, 8... Electrical energy limiting circuit, 9... Container, 10... Connection port, 11
...adjustment device.

Claims (1)

[Scope of utility model registration request] A transmitter having a flameproof construction, which is placed in a hazardous location and has a gas detection element, a zero adjustment circuit calibration circuit, an electrical energy limiting circuit, and a connection port, and the output of the gas detection element is led to the connection port via the electrical energy limiting circuit. a receiving section that is placed in a non-hazardous location away from the transmitting section and receives the output from the transmitting section and displays gas information; and the detecting section that is adjacent to the transmitting section and connectable to the connection port. What is claimed is: 1. A gas detection and alarm device comprising an adjustment device having an intrinsically safe explosion-proof structure that measures the output of an element, and wherein the adjustment of the transmitter is performed near the transmitter.