CN2142572Y

CN2142572Y - Harmful gas detector

Info

Publication number: CN2142572Y
Application number: CN 92232565
Authority: CN
Inventors: 刘庆
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-09-10
Filing date: 1992-09-10
Publication date: 1993-09-22
Anticipated expiration: 2002-09-10

Abstract

The utility model relates to a harmful gas detector, which can automatically detect the existence of harmful gases of carbon monoxide, sulfur dioxide, liquefied petroleum gas, tobacco smoke, etc. in air. The detector can works and automatically warn or control the working of an exhaust blower for removing the harmful gas, when the concentration achieves 0.1%. The gas sensor having the variation of the variable resistance property of the harmful gas is adopted as a sensor; a corresponding control circuit is matched for realizing the automatic detection of the harmful gas. The utility model has safety, high integrated degree, long-term live line work and no any interference for other electric appliance.

Description

Harmful gas detector

The utility model relates to a kind of detector.Particularly adopt the sensor that constitutes by gas sensor, can detect carbon monoxide (CO), sulphuric dioxide (SO2), liquefied petroleum gas (LPG) automatically, and contain the detecting device of harmful and flammable explosive gas such as nicotine.

Carbon monoxide (CO is commonly called as coal gas) is the harmful gas of no color or smell, it can with blood of human body in carry oxygen haemoglobin (Hb) form stable complex compound COHb.COHb is in case after forming, just make haemoglobin lose the ability of delivering oxygen.So CO poisons and will cause organizing low mass formed by blood stasis, if 50% haemoglobin combines with CO and can cause myocardial necrosis in the blood.Because CO is the gas of no color or smell, the naked eyes that can't choose and detected by scent.In testing laboratory can with carbon monoxide and oxygen combustion obtain carbon dioxide method check carbon monoxide have that (chemical equation is: 2CO+O2=CO2).But this kind method will have certain difficulty if be used for the check of daily life environment.In addition, sulphuric dioxide (SO2) is the colourless toxic gas that penetrating odor is arranged.When sucking the air of content of sulfur dioxide, the people is panted and lose consciousness because of poisoning more than 0.2%.Sulphuric dioxide is that harm is bigger a kind of in the atmospheric pollution.Mainly be the sulphur in oil and the coal, exhausted major part is oxidized to sulphuric dioxide and enters atmosphere during burning.Because sulphuric dioxide has penetrating odor, detects and is not difficult.But how the concentration with this gas is controlled at harmless degree below 0.1%, again by means of gas analyzer and chemistry laboratory.Equally, the leakage of liquefied petroleum gas (LPG) can set off an explosion; The people sucks the smog contain nicotine and can impair one's health, these all be people may with the problem of often running into.

The purpose of this utility model is to provide a kind of detecting device that can detect above-mentioned harmful gas rapidly, exactly to prevent to poison and the generation of explosive incident the safety of protection people's life and property.

The purpose of this utility model is achieved in that utilization has the resistive gas sensor of change as sensor to harmful gas.When the concentration of harmful gas reaches 0.1% near sensor.The internal resistance of sensor changes, and sample circuit send comparison, amplifying circuit after adopting this variable quantity, after comparing, amplifying signal is delivered to output terminal, drives the loaded work piece that is connected to output terminal.Show that harmful gas exists.When harmful gas concentration was lower than 0.1%, circuit was not worked, and output terminal does not have signal output.

The utility model is because be to adopt sensor directly to detect, and not only speed is fast so detect than chemical mode and gas analyzer, and has more accuracy.

Below in conjunction with drawings and Examples the utility model is further specified.

Fig. 1 is an electrical schematic diagram of the present utility model.

Among Fig. 1, PT is that gas sensor it and integrated circuit (IC) 1 and controllable silicon SCR and potentiometer R1 constitute sample circuit, and integrated circuit (IC) 2 and resistance R 2 constitute comparator circuits, integrated circuit (IC) 3 and capacitor C1, C2, C3 and resistance R 3, R4 and R5 constitute amplification output circuit.

When harmful gas and sensor (PT) when contacting, the internal resistance of PT will reduce.Electric current flows through potentiometer R1.The potential difference signal that the R1 cursor slide two ends that are connected with controllable silicon (SCR) trigger end produce triggers the SCR conducting.Signal send comparison, amplifying circuit after by resistance R 2 dividing potential drops.After C3, after the R5 filtering signal sent output terminal, loaded work piece.And when harmful gas concentration was lower than 0.1%, the internal resistance of PT recovered initial value, and no current flows through R1, not conducting of SCR, and circuit is not worked, the output of output terminal no signal, load quits work.

Fig. 2 is the electrical schematic diagram of embodiment 1 of the present utility model.

It is the automatic removal device of harmful gas that is made of the utility model and controlled vent fan.Jc is output terminal load of the present utility model---the normally opened contact of relay J among the figure, and D is controlled vent fan motor.When the concentration of harmful gas reached 0.1% near sensor of the present utility model, the utility model sampling was after control signal is exported in relatively amplification, and relay coil gets electric, normally opened contact Jc closure, and the vent fan electrical power is discharged harmful gas.When harmful gas concentration was lower than 0.1%, the utility model was inoperative, the output of output terminal no signal, and relay breaker point Jc opens, and the vent fan motor quits work.

Fig. 3 is the electrical schematic diagram of embodiment 2 of the present utility model.

It is the harmful gas autoalarm that is made of the utility model and controlled hummer and pilot lamp.Jc is for the novel output terminal load of this usefulness---the normally opened contact of relay J, Y and Lp are respectively controlled hummer and pilot lamp among the figure.When the concentration of harmful gas reached 0.1% near sensor of the present utility model, the utility model sampling was after control signal is exported in relatively amplification, and relay coil gets electric, normally opened contact Jc closure, and hummer and pilot lamp are reported to the police simultaneously.

Fig. 4 is a structure cut-open view of the present utility model.

Among the figure: 1 casing, 2 sensors (PT), 3 relays (J), 4 output end binding posts, 5 transformers (B), 6 power leads and plug, 7 electronic circuit boards (summary).

Claims

1, the detecting device of harmful gas, particularly can detect various harmful detectors automatically, it is by sensor (2), relay (3), output terminal load (gas exhauster or hummer) binding post (4), power transformer (5), power lead (6), control circuit (7) and casing (1) constitute, it is characterized in that adopting harmful gas is had the gas sensor of the resistive variation of change as sensor, automatically detect carbon monoxide, sulphuric dioxide, liquefied petroleum gas (LPG) and contain harmful and flammable explosive gas such as nicotine, and detecting device is reported to the police or is controlled gas exhauster and will do harm to the gas removal when harmful gas concentration reaches certain value after.

2, according to claim 1 described detecting device, it is characterized in that the normally opened contact of detecting device repeat circuit is concatenated in the supply line of gas exhauster by binding post (4), by detecting device by relay contact closure with disconnect opening and stopping of control gas exhauster.

3, according to claim 1 described detecting device, it is characterized in that the normally opened contact of detecting device repeat circuit is concatenated in the supply line of hummer and pilot lamp by binding post (4), by detecting device by relay contact closure and the work that disconnects control hummer and pilot lamp with stop.