JPS6031049A - Atmosphere detecting apparatus - Google Patents

Abstract

PURPOSE:To enable durable and automatic detection of gas atmosphere, by installing a plurality of atmosphere sensor elements, switching means allowing these elements to act after consecutive switching and judging means for atmosphere responding to the sensor. CONSTITUTION:Semi-fixed resistances VR1-VR4 are connected in series to sensible bodies S1-S4 respectively and the individual resistance, in response to resistance value of the sensible bodies S1-S4 in a concentration at the start of alarm is adjusted in such a way that each output voltage V1-V4 becomes equal. Upon operating interlinked change-over switches SW1, SW2, by heaters H1-H4 at the initial stage of receiving a current, the sensible bodies S1-S4 are heated and an output voltage VS is issued. This VS is delivered to a discriminating circuit for the gas atmosphere. By setting life of the gas detection element in such a way that, the count of generations of output signal VO at its predetermined value causes automatic switching to the following detecting element, the element, upon its reaching the expiration of its life, can automatically cause the succeeding detecting element to operate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an atmosphere detection device.5 [Background Art] Atmosphere sensor elements such as general K and combustible gas detection elements have a problem of short lifespan.

[Purpose of the invention]

An object of the present invention is to provide an atmosphere detection device that can detect the atmosphere over a long period of time.

[Disclosure of the invention]

The atmosphere detection device of the present invention includes a plurality of atmosphere sensor elements disposed in a detection area, a switching means for sequentially switching and operating these atmosphere sensor elements, and a determining means for determining the atmosphere in response to each of the atmosphere sensor elements. It is equipped with the following.

An embodiment of the present invention will be described with reference to FIGS. 1 to 3. That is, this atmosphere detection device has a configuration in which four combustible gas detection elements are combined, as shown in Fig. 1.
The respective gas sensitive bodies S, , S2. Heat S3°S4.

Semi-fixed resistors VR, VH2, VH2, and VH2 are gas sensitive elements S and S2, respectively. S3. S4 is connected in series, and each resistance value is the gas sensitive element S in the gas concentration at the start of the alarm, s3. Depending on the s3.84O resistance value, each output voltage v0. v2. v3. v, are adjusted so that they are equal. When all of the changeover switches are switched, the changeover switch sw2 is also switched, and the corresponding gas sensitive body (S work in Figure 1) is heated by the heater (H workpiece in Figure 1) that has started power supply. ,
The output voltage (■ in FIG. 1) is taken out as the output voltage V8 via the changeover switch. This output voltage (8) is input to a discrimination circuit (not shown) to discriminate the gas atmosphere.

FIG. 2 shows a cross-sectional view of the gas detection element housing portion, and FIG. 3 shows a plan view thereof. 1 is a case with 4 storage rooms 2m long
, 2b, 2o, 2d', and each storage chamber 2a~
2d, the gas sensitive body S~S4 and heater H~H
4 gas sensing elements T2, each with T2.
T3. T4 is stored individually.

Reference numerals 3a, 3b, 3C, and 3d are lids for individually sealing and closing each of the storage chambers 23 to 2d, and the outer periphery thereof is in close contact with the case 1 via a packing 4 to maintain airtightness. Lid 3a~
3dVi, and mounting arms 5a, 5b, 5c each made of a combustible material on the back side thereof.

A mounting arm 5d is provided protrudingly, and the tip of the mounting arm 5d is hooked onto the back side of the case 1 to hold the lids 38 to 3d. Storage room 2R (2b, 2Q.

2d), if the heaters H, (H2, H3, H4> in The airtightness of chamber 2K (2b, 2C, 2d) is released and the gas sensitive part S (T) in the gas detection element T (T2, T3, T4) is released.
S2.83.84) will be exposed to the atmosphere. 5a, 5b, 5e, 5d are semi-fixed resistance VR work, VH
2, VH2, is an operation knob for adjusting the resistance value of VH2, and 7 is the changeover switch history 0. This is an operation knob for switching the history.

As a result of this configuration, if a problem such as deterioration or failure occurs in the gas detection element (for example, T-piece), the changeover switch history is set to 0. By switching sw2 and activating another gas detection element (for example, T2), that gas detection element can continue to detect the gas atmosphere, and by sequentially switching the gas detection elements T0 to T4 in this way, It becomes possible to detect gas atmospheres over a wide range of areas.

Another embodiment of the invention will be described with reference to FIGS. 4 to 6. That is, in place of the switches □ and □ of the above embodiment, this atmosphere detection device uses a scanner 8 that selects the gas sensitive bodies 80 to S4, and selects the heaters H to H4, as shown in FIG. When the output voltage (2) obtained from the scanner 9 and the gas sensitive body (S4) exceeds a predetermined value, a signal (2) is output. Comparator C that produces , and signal output ■. A counter 10 for measuring the departure of the ship, and a counter 1
A microcomputer 11 is used which controls the scanner 8.9 by outputting 0. The other configurations are the same as those of the above embodiment.

The operation of this device is as follows. Now, scanner 8
Assume that the output voltage V mode, that is, the gas sensitive body S mode is selected. Since the scanner 9 is linked with the scanner 8 by the microcomputer 11 (5), the heater H is energized and the gas sensitive body S is heated. Therefore, in this state, the gas atmosphere is detected by the gas sensitive element S. When the gas concentration exceeds a predetermined value in this state, a signal is output from comparator C. is issued and a gas leak alarm is issued via the discrimination circuit. This number of alarms, that is, the signal output V. The number of occurrences of is counted by a counter 10, and when this count reaches a predetermined value, the scanner 8.9 is activated by the microcomputer 11 to switch to the next gas sensitive body S2 and heater H2 side. At the same time, the counter 10 is reset. The subsequent operation is the same as above, and when the gas leak alarm is emitted a predetermined number of times, the next gas sensitive element s3.
S, and heaters H3 and H are automatically switched in sequence.

By the way, the combustible gas detection element outputs a signal ■. This is caused by (1) gas leaks, (2) periodic sensor tests, and (3)
) This is a case of false alarm due to some reason. Considering the number of times, (1) is quite small and (2) is proportional to the period of use. (3) It will increase due to higher sensitivity (deterioration) of Fi combustible gas detection elements. Signal output■. (2) is predominant in the number of occurrences under normal conditions, but (3) also increases in places with harsh atmospheres. For gas leak alarms, (3)
One aspect of lifespan is that it increases. This outputs a signal indicating the lifespan of the combustible gas detection element■. This shows that it can be evaluated based on the number of occurrences. In other words, the lifespan of a gas detection element corresponds to the period of periodic testing if the sensitivity of the combustible gas detection element is not increased, but if the sensitivity is increased, the number of false alarms increases and the usage period becomes shorter. . FIGS. 5 and 6 show the increased sensitivity of two types of gas detection elements, and the increased sensitivity of the element shown in FIG. 5 is not very large and there is no false alarm. However, the element shown in FIG. 6 is highly sensitive, and if left as is, even a small amount of gas will be judged as a gas leak. Therefore, the number of false alarms is as low as 5 for the element in FIG.
There will be more of them than the elements shown in the figure, and their lifespan will come sooner.

In this way, the lifespan of the gas sensing element is output as a signal■.

As a result, the output signal ■ can be evaluated by the number of occurrences, as in the above embodiment. If the configuration is configured so that the number of occurrences of gas is counted and the gas detection element reaches a predetermined value, it will automatically switch to the next gas detection element.When the operating gas detection element reaches the end of its life, the next gas detection element will be automatically switched It is possible to automatically and stably detect the gas atmosphere over a long period of time.

〔Effect of the invention〕

According to the atmosphere detection device of the present invention, the effect that the atmosphere can be detected for a long period of time can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of one embodiment of the present invention, FIG. 2 is a sectional view of a gas detection element housed in a case, FIG. 3 is a front view thereof, and FIG. 4 is a configuration diagram of another embodiment. FIG. 5 and FIG. 6 are diagrams showing the sensitivity enhancement characteristics of the gas detection element. T-work~T4...Gas detection element, S-work~S4...Gas sensitive body,■yo~H4...Heater, Seat□, 5w2-
・・Choice switch

Claims (2)

[Claims] (1) Atmosphere detection comprising a plurality of atmosphere sensor elements arranged in a detection area, a switching means that sequentially switches and operates these atmosphere sensor elements, and a discrimination means that discriminates the atmosphere in response to each of the atmosphere sensor elements. Device. (2) The atmosphere sensor element is a gas detection element that includes a gas sensitive body and a heater that heats the gas sensitive body, and the switching means selectively extracts the output voltage from each gas sensitive body. a first changeover switch;
The atmosphere detection device according to claim 1, comprising a second changeover switch that changes the power supply path to the corresponding heater in conjunction with the changeover operation of the changeover switch.