CN1035404C - Methane sensor - Google Patents

Abstract

The present invention relates to a methane sensor, provided with a detecting electric bridge for the methane having high concentration and low concentration, a monolithic microcomputer system, and a plurality of functional circuits relating to the display, the alarm and the signal output; the detecting electric bridge for the methane having high concentration and low concentration can carry out the detection according to the high and low concentration of the methane. As the methane sensor can continuously detect the concentration of the methane, the measuring range is wide; the monolithic microcomputer system provides an intelligent function for the sensor, and the response speed to the detection is accelerated; in addition, a power-off control quantity signal can also be output, and the detonated power supply can be quickly cut off when the concentration of the methane reaches to the power-off point. Accordingly, the safety of the coal mine production can be improved by using the methane sensor.

Description

Be used to monitor the device of methane concentration

The present invention relates to a kind of place such as driving face and return aircourse detection under the coal mine, demonstration methane concentration of being used for, realization sound, light are reported to the police when methane concentration transfinites, and can export the device of the monitoring methane concentration of methane concentration square-wave signal.

Can realize above-mentioned functions, and representative methane concentration monitoring device is a FDZB-ZC type methane transducer, the heat catalytic element that this methane transducer adopts two platinum alloy to make detects methane concentration, and wherein one surface scribbles catalyzer, is detecting element; Another surface is coated with inert substance, is temperature compensating element; To insert through strict this a pair of element of selecting collocation and detect as shown in Figure 1 on two arms of electric bridge, pass to suitable working current, when methane concentration is zero, electric bridge is transferred to equilibrium state, when methane contacts with the detecting element that scribbles catalyzer, methane is borrowed the element surface temperature and flameless burning, component temperature is raise, and resistance increases, the electric bridge out of trim, the potential difference (PD) of measuring bridge output terminal has promptly been measured methane concentration.This detecting element can only detect the methane of low concentration, when methane concentration 〉=3.5%, must implement power-off protection to detecting electric bridge, and therefore, the sensing range of this methane transducer is little.In addition, though this methane transducer has adopted the technology of Highgrade integration on circuit design, but do not reach intelligentized degree after all, therefore, the detection response speed is slow, is generally 20-30 second, and this point is for gassy mine, just might be when the sensor unreacted be come, the accident of promptly having blasted.Moreover this methane transducer does not possess outage controlled quentity controlled variable output function, can not implement automatic control to long-range circuit breaker, therefore, reports to the police, but still can not in time cut off the ignition source effectively though sent transfinite sound, light of methane concentration.

It is wide to the purpose of this invention is to provide a kind of measurement range, can hold the device of monitoring methane concentration in the environment relaying continuation of insurance of high methane concentration.

Technical solution of the present invention is: high concentration methane is set detects electric bridge, by platinum alloy make be contained in the temperature compensating element in sealed air chamber and the ventilation air chamber respectively and its surface temperature descends when collide with methane molecule detecting element is connected on two arms that detect electric bridge, and high concentration methane detects electric bridge and detects electric bridge with low-concentration methane and changed by high-concentration and low-concentration switching relay control realization work.

Further illustrate detailed content of the present invention below in conjunction with drawings and Examples.

Fig. 1: methane concentration detects the electric bridge fundamental diagram;

Fig. 2: the complete machine block scheme of the embodiment of the invention;

Fig. 3: embodiment of the invention circuit theory diagrams.

As shown in Figure 3: embodiments of the invention detect electric bridge, single-chip microprocessor system and functional circuit by methane concentration and form, wherein functional circuit is one or more combinations of following functional circuit: the methane concentration sound alarm circuit that transfinites, the methane concentration optical alarm circuit that transfinites, methane concentration digital display circuit, methane concentration square-wave signal output circuit and outage controlled quentity controlled variable output circuit.

Methane concentration detects electric bridge and comprises that high concentration methane detects electric bridge and low-concentration methane detects electric bridge, two detect electric bridge by height, low concentration switching relay (RL) control realization work conversion, two detecting element and the temperature compensating elements that detect electric bridge are connected on respectively on two arms of two detection electric bridges, and all make with platinum alloy, wherein the surface of low dense detecting element (CT1) scribbles catalyzer, the surface of low dense temperature compensating element (CT2) scribbles lazy tail material, and low dense detecting element (CT1), low dense temperature compensating element (CT2) and high dense detecting element (HC2) are contained in respectively in three ventilation air chambers, high dense temperature compensating element (HC1) then is contained in the sealed air chamber, the dense detecting element of described height is a kind of when colliding with methane molecule, and its surface temperature is decline status detection element.

Single-chip microprocessor system is arranged on and detects between the electric bridge congenerous circuit, is made up of pre-amplification circuit, A/D converter and single chip microcomputer.

Pre-amplification circuit is that the voltage signal that will detect electric bridge output amplifies, and the output analog voltage signal.A/D converter is the analog voltage signal that pre-amplification circuit is exported to be converted to be suitable for the digital signal that single chip microcomputer is handled.Present embodiment employing ICL7650 high precision gradually ripple is made pre-amplification circuit from steady zero operational amplifier, adopts the ADC0804 converter to make A/D converter.

Single chip microcomputer is the master control unit of present embodiment, adopts 80C31 to make single-chip microcomputer, adopts 27C648K-EPROM to make the external program memory, adopts 74HC373 to make the 8D latch.1-the 8th pin of single-chip microcomputer is the P1 mouth, 10-the 17th pin is the P3 mouth, 21-the 28th pin is the P2 mouth, 32-the 39th pin is the P0 mouth, the P1 mouth connects by integrated resistor (RP8 * 22K Ω) same darlington array (MC1413), and comes conducting or end following functional circuit by darlington array (MC1413): the charactron in the digital display circuit (L1-L4); Light emitting diode in the sound alarm circuit (D6-D11); Transformer in the optical alarm circuit (TR) primary coil goes to drive piezo by the secondary side coil output of transformer (TR) then; Coil in the high-concentration and low-concentration switching relay (RL) makes normally closed contact disconnect the normally opened contact closure after the energising.The 10th, 12,14,15,16 pin in the P3 mouth are connected with the same Schmidt trigger of single-chip microcomputer the 9th pin (CD40106), wherein the 10th pin is the power-off signal control line, by Schmidt trigger (CD40106) conducting or by outage controlled quentity controlled variable output circuit, this circuit is made up of triode (T1) and current-limiting resistance (R1, R2), the current collection of triode (T1) is power-off signal control output end (RL-C) very, be connected with long-range circuit breaker, to realize the outage control function.The 16th pin (WR) is the make-and-break signal control line of the 8D latch (74HC373) in the digital display circuit, by the Schmidt trigger conducting or in the digital display circuit 8D latch, (WR) becomes low level when the 16th pin, when Schmidt trigger oppositely becomes high level and be added to the 11st pin (LE) of 8D latch, could squeeze into the 8D latch from the defeated 8 next position digital signals of P0 mouth, and be added on the data line of charactron (L1-L4) through integrated resistor (RP8 * 510 Ω), the 11st pin is the methane concentration output line in the P3 mouth, single-chip microcomputer is by the 11st pin conducting or by methane concentration square-wave signal output circuit, this circuit is by triode (T2) and current-limiting resistance (R3, R4) form, the current collection of triode (T2) is square-wave signal output terminal (FOUT) very.The 13rd pin links to each other with the 3rd pin (WR) with the 5th pin (INTR) of A/D converter, the 17th pin (RD) links to each other with the 2nd pin (RD) of A/D converter, the 2nd pin of A/D converter is the read signal control line, after A/D converted, low level pulse signal of the 5th pin output, this signal are input to the 3rd pin made A/D converter start conversion next time, be input to the 13rd pin of single-chip microcomputer simultaneously, send interrupt request to single-chip microcomputer, single-chip microcomputer responds interruption where necessary, reads the data of A/D converter output.The P2 mouth links to each other with the most-significant byte address wire of external program memory as the most-significant byte address bus; The 29th pin is an external program memory select lines, is connected with the 22nd pin (OE) of external program memory.The 30th pin is address latch signal line (ALE), be connected with the 11st pin of 8D latch and the 20th pin (CE) of external program memory, when this pin is high level, the least-significant byte address signal is squeezed into the 8D latch, when this pin is low level, the 8D latch keeps latch mode, and the external program memory is passed to single-chip microcomputer by gating with command signal.The 31st pin ground connection makes the monolithic function utilize the external program memory.The P0 mouth is as data and least-significant byte address bus.Integrated resistor (RP8 * 22K Ω) links to each other with the P0 mouth, and the next resistance as this mouthful makes single-chip microcomputer P0 mouth when resetting can not be in vacant state.

Present embodiment also be equipped with by+fixed stably depressors of 5V three ends (MC7805) ,+the fixed stably depressors of 6V three ends (MC7806) and-power circuit that 5V voltage generator (CD7660) is formed, wherein+5V (VCC) stabilized voltage supply mainly uses for detecting circuit such as electric bridge, single-chip microcomputer, + 6V (VDD) stabilized voltage supply is mainly for showing and circuit uses such as sound, light warning that-5V voltage uses for the ICL7650 amplifier.

It is to utilize " thermal conduction principle " of detecting element to realize that the high concentration methane that the present invention adopts detects electric bridge, when methane molecule during with the surface collision of detecting element, the temperature of detecting element descends, therefore, this detection electric bridge can be used for high concentration methane and detect, thereby the sensing range of methane concentration monitoring device is enlarged, reach the concentration range that can detect 0-40%CH, in addition, the present invention utilizes the micro computer prediction, control is quickened response speed greatly, increases again and resolves electric control amount output function, therefore, the present invention has had intelligentized characteristic again, uses it can improve the security of Coal Production.

Claims (1)

1, a kind of device that is used to monitor methane concentration, one or more combinations with low-concentration methane detection electric bridge and following functional circuit: methane concentration digital display circuit, the methane concentration sound alarm circuit that transfinites, methane concentration transfinite optical alarm circuit and methane concentration square-wave signal output circuit, it is characterized in that: also have high concentration methane and detect electric bridge, by platinum alloy make be contained in the temperature compensating element (HC1) in sealed air chamber and the ventilation air chamber respectively and its surface temperature descends when collide with methane molecule detecting element (HC2) is connected on two arms that detect electric bridge, and high concentration methane detects electric bridge and detects electric bridge with low-concentration methane and changed by high-concentration and low-concentration switching relay (RL) control realization work.

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