JP2011196727A - Extinction type smoke sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extinction type smoke sensor, capable of discriminating a fire with high accuracy, by eliminating effect of a noise source.SOLUTION: The extinction type smoke sensor includes: a smoke detection space 5; an optical path 7 for smoke detection formed to get across the smoke detection space 5; an optical path 9 for compensation; a light emitting element 11; a light receiving element 13 disposed so as to be able to receive light which passed through the optical path 7 for smoke detection and the optical path 9 for compensation; a shutter unit 15 provided at the optical path 7 for smoke detection for switching light shielding and light transmission of the passing light; and a fire discriminator 17a which uses the amounts of light received by the light receiving element 13 as a result of light shielding and light transmission at the optical path 7 for smoke detection by the shutter unit 15 in a normal state as a first and a second reference values, uses the amounts of light received by the light receiving element 13 as a result of light shielding and light transmission at the optical path 7 for smoke detection by the shutter unit 15 in a monitoring state as a first and a second monitoring values, determines a change rate in the amount of light received by the light receiving element 13 based on the first reference value and the first monitoring value, and performs fire discrimination based on the change rate, the second reference value, and the first and second monitoring values.

Description

本発明は、検煙空間に流入した煙により発光素子からの照射光の受光素子への受光量が減少することによって火災を判別する減光式煙感知器に関する。   The present invention relates to a light reduction type smoke detector that determines a fire by reducing the amount of light irradiated from a light emitting element to a light receiving element due to smoke flowing into a smoke detection space.

減光式煙感知器は、検煙空間に流入した煙により発光素子からの照射光の受光素子への受光量が減少することによって火災を判別する。
減光式煙感知器には、検煙空間を形成する筐体内に発光素子と受光素子を設置して、コンパクト化を図ったいわゆるスポット型の減光式煙感知器がある。
スポット型の減光式煙感知器は、検煙空間（発光素子と受光素子との光路長）を長くすることが困難なため、検煙空間内での煙濃度変化率を算出するにあたって、受光素子による受光量の変化率が微小となり、受光量以外のノイズ源の影響が相対的に大きくなる。
したがって、受光量の変化を正確に検知して正しく火災判別をするためには、受光素子の受光量以外のノイズ源による影響を排除するために補償することが必要となる。
ノイズ源としては、経年による受光素子への埃の付着や、周囲温度変化による受光素子の特性変化などが挙げられる。 The dimming smoke detector determines a fire by reducing the amount of light received from the light emitting element to the light receiving element due to the smoke flowing into the smoke detection space.
As the dimming smoke detector, there is a so-called spot-type dimming smoke detector in which a light emitting element and a light receiving element are installed in a casing forming a smoke detection space to achieve a compact size.
Spot-type dimming smoke detectors are difficult to lengthen the smoke detection space (the optical path length between the light emitting element and the light receiving element). Therefore, when calculating the smoke concentration change rate in the smoke detection space, The rate of change in the amount of light received by the element becomes minute, and the influence of noise sources other than the amount of received light becomes relatively large.
Therefore, in order to accurately detect a change in the amount of received light and correctly determine the fire, it is necessary to compensate to eliminate the influence of noise sources other than the amount of received light of the light receiving element.
Examples of noise sources include dust adhering to the light receiving element over time, and changes in the characteristics of the light receiving element due to changes in ambient temperature.

このような問題を解決するものとして、特許文献１には、「光源と、該光源からの光束を二分し、二本の光路を形成する隔壁と、二分された上記光束がそれぞれ入射する少なくとも２個の受光路とを有し、上記二本の光路のうち一方を上記隔壁の周囲からのみ外気が流入できる補償用光路とし、他方を外気が容易に流入できる検出用光路として、両光路の信号量の差によって警報信号を得るようにした透過光式煙感知器」が記載されている（特許文献１の特許請求の範囲における「おいて」以前参照）。   In order to solve such a problem, Patent Document 1 discloses that “a light source, a partition wall that bisects a light beam from the light source, and forms two optical paths, and at least two beams into which the bisected light beam is incident. Of the two optical paths, and one of the two optical paths is a compensation optical path through which the outside air can flow only from around the partition wall, and the other is a detection optical path through which the outside air can easily flow in. A transmitted light type smoke detector that obtains an alarm signal according to a difference in quantity ”is described (refer to“ before ”in the claims of Patent Document 1).

特開昭５３−１３４４８３号公報JP-A-53-134483

特許文献１に記載された透過光式煙感知器は、検出用光路および補償用光路という二本の光路にそれぞれ受光素子を配設して、各受光素子の受光信号の差に基づくことによって、単独の受光素子の、例えば埃堆積などによる経年変化を補償しようとするものである。
しかしながら、特許文献１に記載のものは、個別の２個の受光素子を用いているため、各受光素子の個体差に基づく補正を行うことができない。つまり、２個の受光素子が経年によって全く同様の経年変化をするとは限らず、また埃の堆積にしても２個の受光素子の設置位置が異なるので堆積の仕方も異なることが十分考えられ、さらに温度の影響についても配設位置が異なるため、特に火災時の煙等の高温の気流の影響に差異が生ずることも考えられる。
このように、特許文献１に記載の透過光式煙感知器では、２個の受光素子を用いているため、高精度の補償を行うことができなかった。 The transmitted light type smoke detector described in Patent Document 1 is provided with a light receiving element in each of two optical paths, a detection optical path and a compensation optical path, and based on a difference between light reception signals of the respective light receiving elements, A single light receiving element is intended to compensate for aging due to, for example, dust accumulation.
However, since the thing of patent document 1 uses two separate light receiving elements, it cannot correct based on the individual difference of each light receiving element. In other words, the two light receiving elements do not always have the same aging with the passage of time, and even if dust is accumulated, the installation positions of the two light receiving elements are different, so it is conceivable that the deposition method is also different. Furthermore, since the arrangement position is also different with respect to the influence of temperature, it is conceivable that a difference occurs in the influence of a high-temperature air flow such as smoke during a fire.
Thus, since the transmitted light type smoke detector described in Patent Document 1 uses two light receiving elements, high-precision compensation cannot be performed.

この発明は、かかる課題を解決するためになされたものであり、光路長を長くとることが困難なスポット型の減光式煙感知器において、温度変化や埃の堆積といったノイズ源の影響を確実に排除して高精度な火災判別ができる減光式煙感知器を得ることを目的としている。   The present invention has been made to solve such a problem, and in a spot-type dimming smoke detector in which it is difficult to take a long optical path length, the effects of noise sources such as temperature changes and dust accumulation are reliably ensured. The aim is to obtain a dimming smoke detector that can be used for fire detection with high accuracy.

（１）本発明に係る減光式煙感知器は、煙が流入する検煙空間と、該検煙空間を横断するように形成された検煙用光路と、前記検煙空間とは分離して設けられた補償用光路と、前記検煙用光路及び前記補償用光路に向けて発光する発光素子と、前記検煙用光路及び前記補償用光路を通過した光を受光可能に配設された受光素子と、前記検煙用光路に設けられて該検煙用光路を通過する光の遮光と透光を切り換えるシャッタ手段と、基準状態において前記シャッタ手段によって前記検煙用光路を遮光及び透光して前記受光素子によって受光された受光量を第一及び第二の基準値とし、また、監視状態において前記シャッタ手段によって前記検煙用光路を遮光及び透光して前記受光素子によって受光された受光量を第一及び第二の監視値とし、
前記第一の基準値と第一の監視値とに基づいて前記受光素子の受光量の変化率を求め、
当該変化率と前記第二の基準値と第一及び第二の監視値とに基づいて火災の判別を行う火災判別手段とを備えたことを特徴とするものである。 (1) A dimming smoke detector according to the present invention separates a smoke detection space into which smoke flows, a light detection optical path formed so as to cross the smoke detection space, and the smoke detection space. A compensation optical path, a light emitting element that emits light toward the smoke detection optical path and the compensation optical path, and a light that passes through the smoke detection optical path and the compensation optical path are disposed so as to receive light. A light receiving element; shutter means provided in the smoke detection optical path for switching between light shielding and light transmission of light passing through the smoke detection optical path; and light shielding and light transmission by the shutter means in the reference state. The received light amount received by the light receiving element is used as the first and second reference values, and the smoke detecting optical path is shielded and transmitted by the shutter means in the monitoring state and received by the light receiving element. The amount of light received is the first and second monitoring values,
Based on the first reference value and the first monitoring value, to determine the rate of change in the amount of light received by the light receiving element,
Fire distinguishing means for distinguishing fire based on the rate of change, the second reference value, and the first and second monitoring values is provided.

（２）また、上記（１）に記載のものにおいて、前記火災判別手段は、
前記第二の基準値と第一の基準値との差分の値と、前記変化率とに基づいて、前記差分の値を、前記監視状態と同様のノイズ源発生状態にあるときの補正基準値に補正し、
当該補正基準値と、前記第二の監視値と第一の監視値との差分の値と、に基づいて火災の判別を行うことを特徴とするものである。 (2) Further, in the above (1), the fire discrimination means is
Based on the difference value between the second reference value and the first reference value and the rate of change, the difference value is a correction reference value when the noise source is in the same state as the monitoring state. To
Fire discrimination is performed based on the correction reference value and a difference value between the second monitoring value and the first monitoring value.

（３）また、上記（１）に記載のものにおいて、前記火災判別手段は、
前記第二の監視値と第一の監視値との差分の値と、前記変化率とに基づいて、前記第二の監視値と第一の監視値との差分の値を、前記基準状態と同様のノイズ源発生状態にあるときの補正監視値に補正し、
前記第二の基準値と第一の基準値との差分の値と、当該補正監視値とに基づいて火災の判別を行うことを特徴とするものである。 (3) Further, in the above (1), the fire discrimination means is
Based on the difference value between the second monitoring value and the first monitoring value and the change rate, the difference value between the second monitoring value and the first monitoring value is set to the reference state. Correct it to the correction monitoring value when it is in the same noise source generation state,
A fire is determined based on a difference value between the second reference value and the first reference value and the corrected monitoring value.

（４）また、上記（１）〜（３）のいずれか１つに記載のものにおいて、前記補償用光路は、ライトガイドによって構成されていることを特徴とするものである。   (4) Further, in any one of the above (1) to (3), the compensation optical path is constituted by a light guide.

（５）また、上記（１）〜（４）のいずれか１つに記載のものにおいて、前記火災判別手段は、受光量に基づいて減光率を演算し、該減光率に基づいて火災の判別を行うことを特徴とするものである。   (5) Further, in any one of the above (1) to (4), the fire determining means calculates a dimming rate based on the amount of received light, and fires based on the dimming rate. This is characterized in that the determination is made.

本発明によれば、単一の受光素子を用いることが可能となり、しかも火災判別動作を行うときに、基準状態においてシャッタ手段によって検煙用光路を遮光及び透光して受光素子によって受光された受光量を第一及び第二の基準値とし、監視状態においてシャッタ手段によって検煙用光路を遮光及び透光して受光素子によって受光された受光量を第一及び第二の監視値をとし、これらのパラメータに基づいて火災判別動作を行う。このとき、第一の基準値と第一の監視値とに基づいて、基準状態と監視状態とによる補償用光路に基づく受光素子の受光量の変化率（出力変化率）を求め、これを利用して火災判別のために必要なパラメータについてノイズ源に関する補正を行ってから（補正基準値に補正してから）火災の判別を行うようにしているので、受光素子の例えば温度や埃の堆積等に起因する出力値の変化（ノイズの影響）を精度良く補償することができ、正確な火災判別を行うことができる。また、受光素子として単一の受光素子を用いれば、従来例で示した２つの受光素子を用いた場合のように、分離配設されることに起因する受光量の差異も生じることがなく、また、個体間の特性のバラツキも生じない。   According to the present invention, it is possible to use a single light receiving element, and when performing a fire discrimination operation, the light detecting element is shielded and transmitted by the shutter means in the reference state and received by the light receiving element. The received light amount is set as the first and second reference values, and in the monitoring state, the light receiving amount received by the light receiving element by blocking and transmitting the light path for smoke detection by the shutter unit is set as the first and second monitored values, A fire discrimination operation is performed based on these parameters. At this time, based on the first reference value and the first monitoring value, a change rate (output change rate) of the light receiving amount of the light receiving element based on the compensation optical path according to the reference state and the monitoring state is obtained and used. Then, after correcting the noise source for the parameters necessary for fire discrimination (after correcting to the correction reference value), fire discrimination is performed. It is possible to accurately compensate for a change in output value (effect of noise) caused by the noise, and to perform accurate fire discrimination. Further, if a single light receiving element is used as the light receiving element, there is no difference in the amount of light received due to the separate arrangement as in the case of using the two light receiving elements shown in the conventional example, In addition, there is no variation in characteristics between individuals.

本発明の一実施の形態に係る減光式煙感知器の構造を説明する説明図である。It is explanatory drawing explaining the structure of the light reduction type smoke sensor which concerns on one embodiment of this invention. 本発明の一実施の形態に係る減光式煙感知器の機能を説明するためのブロック図である。It is a block diagram for demonstrating the function of the light reduction type smoke sensor which concerns on one embodiment of this invention. 本発明の一実施の形態に係る減光式煙感知器の動作を説明する説明図である。It is explanatory drawing explaining operation | movement of the light reduction type smoke sensor which concerns on one embodiment of this invention. 本発明の一実施の形態に係る減光式煙感知器の動作を時系列で示すフローチャートである。It is a flowchart which shows the operation | movement of the light reduction type smoke detector which concerns on one embodiment of this invention in time series. 図４に示したフローチャートにおけるＳ１の処理の詳細を説明するフローチャートである。FIG. 5 is a flowchart for explaining details of a process of S1 in the flowchart shown in FIG. 4. FIG. 図４に示したフローチャートにおけるＳ２の処理の詳細を説明するフローチャートである。FIG. 5 is a flowchart for explaining details of a process of S2 in the flowchart shown in FIG. 4. FIG. 図４に示したフローチャートにおけるＳ３の処理の詳細を説明するフローチャートである。FIG. 5 is a flowchart for explaining details of a process of S3 in the flowchart shown in FIG. 4. FIG. 図４に示したフローチャートにおけるＳ４の処理の詳細を説明するフローチャートである。FIG. 5 is a flowchart for explaining details of a process of S4 in the flowchart shown in FIG. 4. FIG.

図１、図２に基づいて本実施の形態に係る減光式煙感知器を説明する。
本実施の形態に係る減光式煙感知器１は、筐体３内に、煙が流入する検煙空間５と、該検煙空間５を横断するように形成された検煙用光路７と、検煙空間５とは分離して設けられた補償用光路９とを有している。そして、検煙用光路７及び補償用光路９に向けて発光する発光素子としてのＬＥＤ（発光ダイオード）１１と、検煙用光路７及び補償用光路９を通過した光を受光可能に配設された受光素子としてのＰＤ１３（フォトダイオード）と、検煙用光路７に設けられて検煙用光路７を通過する光の遮光と透光を切り換えるシャッタ手段としての液晶シャッタ１５と、ＰＤ１３の受光信号に基づいて火災の判別を行う火災判別手段１７ａを構成するＭＰＵ１７や、ＲＯＭ１９及びＲＡＭ２１等が搭載された回路基板２３と、火災判別手段１７ａによって火災発生があると判別されたときに、火災信号を火災受信機３３に送信する送受信回路２５を備えている。
各構成をさらに詳細に説明する。 The dimming smoke detector according to the present embodiment will be described with reference to FIGS.
The dimming smoke detector 1 according to the present embodiment includes a smoke detection space 5 into which smoke flows and a light detection optical path 7 formed so as to cross the smoke detection space 5 in a housing 3. The compensation optical path 9 is provided separately from the smoke detection space 5. An LED (light emitting diode) 11 as a light emitting element that emits light toward the smoke detection optical path 7 and the compensation optical path 9 and the light that has passed through the smoke detection optical path 7 and the compensation optical path 9 are disposed so as to receive light. A PD 13 (photodiode) as a light receiving element, a liquid crystal shutter 15 as a shutter means provided in the smoke detecting optical path 7 to switch between shielding and transmitting light passing through the smoke detecting optical path 7, and a light receiving signal of the PD 13 When the fire discriminating means 17a determines that a fire has occurred, the MPU 17 constituting the fire discriminating means 17a for determining the fire based on the circuit board 23, the ROM 19 and the RAM 21 and the fire discriminating means 17a A transmission / reception circuit 25 for transmitting to the fire receiver 33 is provided.
Each configuration will be described in more detail.

＜筐体＞
筐体３は、例えば図１に示すように直方体状に形成され、図中、奥側壁部には中央下部側に開口部４が設けられ、また図示せずも手前側壁部にも同様の開口部４が設けられており、この開口部４から煙が導入されるようになっている。
もっとも、筐体３の形状は、直方体状に限定されるものではない。 <Case>
The housing 3 is formed in a rectangular parallelepiped shape as shown in FIG. 1, for example. In the figure, the back side wall is provided with an opening 4 at the center lower side, and a similar opening is also formed in the front side wall, not shown. A portion 4 is provided, and smoke is introduced from the opening 4.
However, the shape of the housing 3 is not limited to a rectangular parallelepiped shape.

＜検煙空間＞
検煙空間５は、筐体３内に形成され、煙が導入される空間である。
検煙空間５は、筐体３内に設けられて、下面を開口するコ字状の隔壁６の内側に形成される。隔壁６は、奥側および手前側壁部に設けられた開口部４が内側に設けられる。これによって、検煙空間５は、開口部４を介して煙を導入することができる。なお、筐体３の内部は、隔壁６によって、検煙空間５（検煙用光路７）と補償用光路９とに区画される。なお、隔壁６はＬＥＤ側にＬＥＤ用窓６ａが形成され、ＰＤ１３側にＰＤ用窓６ｂが形成される。 <Smoke detection space>
The smoke detection space 5 is a space formed in the housing 3 and into which smoke is introduced.
The smoke detection space 5 is provided inside the housing 3 and is formed inside a U-shaped partition wall 6 that opens on the lower surface. As for the partition 6, the opening part 4 provided in the back | inner side and the near side wall part is provided inside. Thereby, the smoke detection space 5 can introduce smoke through the opening 4. The interior of the housing 3 is divided into a smoke detection space 5 (smoke detection optical path 7) and a compensation optical path 9 by a partition wall 6. The partition wall 6 has an LED window 6a formed on the LED side and a PD window 6b formed on the PD 13 side.

＜検煙用光路＞
検煙用光路７は、煙が流入する光路であって、ＬＥＤ１１から照射された光がＬＥＤ用窓６ａ、検煙空間５、液晶シャッタ１５、ＰＤ用窓６ｂを通過してＰＤ１３に至るまでの光の通過路である。 <Light path for smoke detection>
The smoke detection optical path 7 is an optical path through which smoke flows, and the light irradiated from the LED 11 passes through the LED window 6a, the smoke detection space 5, the liquid crystal shutter 15, and the PD window 6b to reach the PD 13. It is a light passage.

＜補償用光路＞
補償用光路９は、煙が流入しない光路であって、ＬＥＤ１１から照射された光が検煙空間５及び液晶シャッタ１５を迂回して（通過せずに）ＰＤ１３に至るまでの光の通過路である。補償用光路９は、例えば導光部としてのライトガイド２７によって形成される。もっとも、補償用光路９の形成方法は、ライトガイド２７に限られず、例えば検煙空間５と分離するための隔壁６のようなもののみで形成してもよい。つまり、補償用光路９として、ライトガイド２７を必要としなくとも、ＬＥＤ１１からの発光をＰＤ１３が直接受光できる構造とすればよく、例えば、図１において、ＬＥＤ用窓６ａおよびＰＤ用窓６ｂの中央部の位置辺りまで、隔壁６の上壁を低くして位置させることによって可能となる。なお、それに合わせて開口部４の上端も下方に位置させて、補償用光路９に煙が流入しない構造とする必要がある。 <Compensation optical path>
The compensation optical path 9 is an optical path through which smoke does not flow, and is a light path through which light emitted from the LED 11 bypasses the smoke detection space 5 and the liquid crystal shutter 15 and does not pass through to the PD 13. is there. The compensation optical path 9 is formed by, for example, a light guide 27 as a light guide. However, the method of forming the compensation optical path 9 is not limited to the light guide 27, and may be formed of only the partition wall 6 for separating from the smoke detection space 5, for example. That is, the compensation optical path 9 may have a structure in which the PD 13 can directly receive the light emitted from the LED 11 without the need for the light guide 27. For example, in FIG. 1, the center of the LED window 6a and the PD window 6b is used. This can be achieved by lowering the upper wall of the partition wall 6 up to the position of the portion. In accordance with this, it is necessary that the upper end of the opening 4 is also positioned below so that smoke does not flow into the compensation optical path 9.

＜ＬＥＤ＞
ＬＥＤ１１は本発明の発光素子に相当するものであり、図２に示すように、発光制御手段１７ｂの制御信号に基づいて発光制御回路２９から発信される信号によって発光が制御される。 <LED>
The LED 11 corresponds to the light emitting element of the present invention, and as shown in FIG. 2, the light emission is controlled by a signal transmitted from the light emission control circuit 29 based on the control signal of the light emission control means 17b.

＜ＰＤ＞
ＰＤ１３は本発明の受光素子に相当するものであり、ＬＥＤ１１から照射された光を受光して受光信号を出力する。受光信号は、受光増幅回路３１によって増幅されてＭＰＵ１７側に送信され、Ａ/Ｄ変換されて、ＭＰＵ１７に入力される。 <PD>
The PD 13 corresponds to the light receiving element of the present invention, and receives light emitted from the LED 11 and outputs a light receiving signal. The light reception signal is amplified by the light reception amplification circuit 31 and transmitted to the MPU 17 side, A / D converted, and input to the MPU 17.

＜液晶シャッタ＞
液晶シャッタ１５は本発明のシャッタ手段に相当するものであり、液晶シャッタ制御手段１７ｃによってシャッタの開閉が制御される。液晶シャッタ１５が開放したときには、検煙用光路７を通過する光が液晶シャッタ１５を透光してＰＤ１３に入射し、液晶シャッタ１５が閉止したときには、検煙用光路７を通過する光が液晶シャッタ１５によって遮光され、ＰＤ１３に入射されない。 <Liquid crystal shutter>
The liquid crystal shutter 15 corresponds to the shutter means of the present invention, and the opening and closing of the shutter is controlled by the liquid crystal shutter control means 17c. When the liquid crystal shutter 15 is opened, the light passing through the smoke detecting optical path 7 is transmitted through the liquid crystal shutter 15 and incident on the PD 13, and when the liquid crystal shutter 15 is closed, the light passing through the smoke detecting optical path 7 is liquid crystal. The light is blocked by the shutter 15 and is not incident on the PD 13.

＜回路基板＞
回路基板２３には、プログラムを記憶するＲＯＭ１９や、データの記憶と読出しができるＲＡＭ２１や、ＲＯＭ１９に記憶されているプログラムを読み出して各種の機能手段を実現するＭＰＵ１７や、Ａ／Ｄ変換器かＤ／Ａ変換器等が搭載されている。発光制御手段１７ｂ、液晶シャッタ制御手段１７ｃ及び火災判別手段１７ａは、ＭＰＵ１７がプログラムを読み出して実行することによって実現される。なお、ＲＯＭ１９、ＲＡＭ２１等もＭＰＵ１７の内部に設けるようにしてもよい。 <Circuit board>
The circuit board 23 includes a ROM 19 for storing a program, a RAM 21 for storing and reading data, an MPU 17 for reading various programs stored in the ROM 19 and realizing various functional means, an A / D converter or a D / A converter etc. are installed. The light emission control unit 17b, the liquid crystal shutter control unit 17c, and the fire determination unit 17a are realized by the MPU 17 reading and executing a program. Note that the ROM 19, RAM 21, etc. may also be provided inside the MPU 17.

＜火災判別手段＞
火災判別手段１７ａは、基準状態において液晶シャッタ１５によって検煙用光路７を遮光して補償用光路９のみを通過してＰＤ１３に受光された受光量を第一の基準値とし、基準状態において液晶シャッタ１５によって検煙用光路７を透光して、検煙用光路７及び補償用光路９を通過してＰＤ１３に受光された受光量を第二の基準値とし、監視状態において液晶シャッタ１５によって検煙用光路７を遮光して補償用光路９のみを通過してＰＤ１３に受光された受光量を第一の監視値とし、また監視状態において液晶シャッタ１５によって検煙用光路７を透光して、検煙用光路７及び補償用光路９を通過してＰＤ１３に受光された受光量を第二の監視値とし、当該第一の基準値と第一の監視値とに基づいてＰＤ１３の受光量の変化率を求め、当該変化率と第二の基準値と第一及び第二の監視値とに基づいて火災の判別を行う。なお、火災判別手段１７ａの処理動作の詳細は後述する。
基準状態とは、煙のない状態であり、例えば、減光式煙感知器１を設置した当初の状態をいう。
監視状態とは、減光式煙感知器１を設置して火災の有無を監視している状態をいう。 <Fire discrimination means>
The fire discriminating means 17a blocks the smoke detection optical path 7 by the liquid crystal shutter 15 in the reference state, passes only the compensation optical path 9 and is received by the PD 13 as a first reference value, and the liquid crystal in the reference state. The amount of light received by the PD 13 after passing through the smoke detection optical path 7 through the shutter 15 and passing through the smoke detection optical path 7 and the compensation optical path 9 is set as a second reference value. The amount of light received by the PD 13 passing through only the compensation optical path 9 while being shielded from the smoke detection optical path 7 is used as a first monitoring value, and the smoke detection optical path 7 is transmitted by the liquid crystal shutter 15 in the monitoring state. Then, the amount of light received by the PD 13 after passing through the smoke detection optical path 7 and the compensation optical path 9 is set as a second monitoring value, and the PD 13 receives the light based on the first reference value and the first monitoring value. Find the rate of change of quantity Discriminating a fire based on the change rate and the second reference value and the first and second monitoring value. Details of the processing operation of the fire discriminating means 17a will be described later.
A reference | standard state is a state without smoke, for example, means the initial state which installed the dimming smoke detector 1. FIG.
The monitoring state refers to a state where the dimming smoke detector 1 is installed to monitor the presence or absence of a fire.

火災判別手段１７ａの火災判別は、煙による減光率が予め定めた閾値を超えているかどうかによって行う。煙による減光率とは、下式で定義される。
減光率［％］＝｛1-（煙ありの受光出力）/（煙なしの受光出力）｝×100
ここで、「煙ありの受光出力」と「煙なしの受光出力」とは、それぞれの検出時期が異なるとノイズ源の発生状態が同一とはいえず、受光出力に含まれるノイズ量が異なるため、正確に減光率が算出できない。そのため、本実施の形態においては、「煙ありの受光出力」又は「煙なしの受光出力」のいずれか一方について、いずれか他方と同様のノイズ源発生状態にあるときの補正基準値に補正することによって、ノイズ源の影響を排除した正確な減光率を算出することができる（詳細は後述する）。 The fire discrimination of the fire discrimination means 17a is performed based on whether or not the light attenuation rate due to smoke exceeds a predetermined threshold value. The extinction rate due to smoke is defined by the following equation.
Dimming rate [%] = {1- (light receiving output with smoke) / (light receiving output without smoke)} x 100
Here, “light reception output with smoke” and “light reception output without smoke” cannot be said to be the same in the noise source generation state at different detection times, and the amount of noise contained in the light reception output is different. The fading rate cannot be calculated accurately. Therefore, in the present embodiment, either “light reception output with smoke” or “light reception output without smoke” is corrected to the correction reference value when the noise source is in the same state as the other. Thus, it is possible to calculate an accurate light attenuation rate that eliminates the influence of the noise source (details will be described later).

＜送受信回路＞
送受信回路２５は、火災判別手段１７ａによって火災発生ありと判別されたときに、火災信号を火災受信機３３に送信する。また、火災受信機３３からの各種信号を受信する。 <Transceiver circuit>
The transmission / reception circuit 25 transmits a fire signal to the fire receiver 33 when the fire determination means 17a determines that a fire has occurred. In addition, various signals from the fire receiver 33 are received.

次に、上記のように構成された本実施の形態の減光式煙感知器１の動作を説明する。減光式煙感知器１の動作としては、減光式煙感知器１を設置した当初に基準値の取得のために行う基準値取得動作と、監視状態において基準値に基づいてＰＤ１３の変化率を求め、この変化率を用いて火災の有無を判別する火災判別動作とがある。以下、各別に説明する。   Next, the operation of the dimming smoke detector 1 of the present embodiment configured as described above will be described. The operation of the dimming smoke detector 1 includes a reference value acquisition operation performed for acquiring a reference value at the beginning of the installation of the dimming smoke detector 1, and a rate of change of the PD 13 based on the reference value in a monitoring state. And a fire discrimination operation for discriminating the presence or absence of a fire using this rate of change. Each will be described below.

＜基準値取得動作＞
基準値取得動作は、減光式煙感知器１を設置した当初に行うものであって、受光素子であるＰＤ１３が経年による変化を生ずる前の基準値を取得する動作である。
図３（ａ）に示すように、液晶シャッタ１５を閉止した状態でＬＥＤ１１を発光し、補償用光路９のみを通過する光をＰＤ１３で受光して受光信号の出力値（受光量）を求め、ＲＡＭ２１に記憶する。この補償用光路９のみを通過したときの受光信号の出力値を受光出力Ａと表記し、特に基準値取得動作のときに取得された受光出力Ａを基準受光出力Ａ（第一の基準値に相当）と表記し、後述する監視状態において取得される受光出力Ａを現在受光出力Ａ（第一の監視値に相当）と表記する。
なお、基準受光出力Ａの具体例としては、例えば、20mVである。 <Reference value acquisition operation>
The reference value acquisition operation is performed at the beginning of the installation of the dimming smoke detector 1 and is an operation of acquiring the reference value before the PD 13 as the light receiving element is changed due to aging.
As shown in FIG. 3A, the LED 11 emits light with the liquid crystal shutter 15 closed, and the light passing through only the compensation optical path 9 is received by the PD 13 to obtain the output value (the amount of received light) of the received light signal. Store in the RAM 21. The output value of the received light signal when only passing through the compensation optical path 9 is denoted as received light output A, and in particular, the received light output A acquired during the reference value acquisition operation is referred to as the reference received light output A (first reference value). The received light output A acquired in a monitoring state to be described later is referred to as the current received light output A (corresponding to the first monitoring value).
A specific example of the reference light reception output A is 20 mV, for example.

次に、図３（ｂ）に示すように、液晶シャッタ１５を開放した状態でＬＥＤ１１を発光し、補償用光路９及び検煙用光路７を通過する光をＰＤ１３で受光して受光信号の出力値を求め、ＲＡＭ２１に記憶する。この補償用光路９及び検煙用光路７を通過したときの受光信号の出力値を受光出力Ｂと表記し、特に基準値取得動作のときに取得された受光出力Ｂを基準受光出力Ｂ（第二の基準値に相当）と表記し、後述する監視状態において取得される受光出力Ｂを現在受光出力Ｂ（第二の監視値に相当）と表記する。
なお、基準受光出力Ｂの具体例としては、例えば、120mVである。 Next, as shown in FIG. 3B, the LED 11 emits light with the liquid crystal shutter 15 opened, and the light passing through the compensation optical path 9 and the smoke detection optical path 7 is received by the PD 13 to output a light reception signal. A value is obtained and stored in the RAM 21. The output value of the received light signal when passing through the compensation optical path 9 and the smoke detecting optical path 7 is expressed as a received light output B, and in particular, the received light output B acquired during the reference value acquiring operation is referred to as the reference received light output B (the first received light output B). The light reception output B acquired in a monitoring state to be described later is expressed as a current light reception output B (corresponding to a second monitoring value).
A specific example of the reference light reception output B is 120 mV, for example.

＜火災判別動作＞
火災判別動作は、監視状態において、常時（例えば、５秒ごと）、火災判別手段１７ａによって行われているものである。
火災判別動作の処理の全体の流れは、図４に示すように、ＬＥＤ１１を発光させてＰＤ１３によって受光して現在受光出力Ａ及び現在受光出力Ｂを記憶する受光出力入力処理（Ｓ１）を行い、基準受光出力Ａと現在受光出力Ａに基づいて出力変化率を算出する出力変化率算出（Ｓ２）を行う。
そして、出力変化率に基づいて、検煙用光路７のみを通過したときの基準受光出力（基準受光出力Ｂ−基準受光出力Ａ）、つまり上記「煙なし受光出力」を、現在受光出力Ｂと同様のノイズ源発生状態にあるときに、検煙用光路７のみを通過したときに得られるであろう現在受光出力（補正基準値に相当）に補正する補正処理を行い（Ｓ３）、さらに減光率ｄを算出し（Ｓ４）、算出した減光率ｄが閾値ｋ以上かどうかの判断を行う（Ｓ５）。
Ｓ５の判断において算出した減光率ｄが閾値ｋ以上の場合には火災信号を送出する（Ｓ６）。他方、Ｓ５の判断において算出した減光率ｄが閾値ｋ未満の場合にはＳ１の処理に戻って同様の処理を繰り返す。
以下、各処理の内容をより詳細に説明する。 <Fire discrimination operation>
The fire discrimination operation is always performed by the fire discrimination means 17a in the monitoring state (for example, every 5 seconds).
As shown in FIG. 4, the overall flow of the fire discrimination operation is to perform a light receiving output input process (S1) in which the LED 11 emits light and is received by the PD 13, and the current light receiving output A and the current light receiving output B are stored. An output change rate calculation (S2) for calculating an output change rate based on the reference received light output A and the current received light output A is performed.
Based on the output change rate, the reference light reception output (reference light reception output B−reference light reception output A) when only passing through the smoke detection optical path 7, that is, the above “light reception output without smoke” is referred to as the current light reception output B. In a similar noise source generation state, correction processing is performed to correct the current received light output (corresponding to the correction reference value) that would be obtained when only passing through the smoke detection optical path 7 (S3), and further reduction The light rate d is calculated (S4), and it is determined whether the calculated light attenuation rate d is equal to or greater than the threshold value k (S5).
When the light attenuation rate d calculated in the determination of S5 is equal to or greater than the threshold value k, a fire signal is sent (S6). On the other hand, when the light attenuation rate d calculated in the determination in S5 is less than the threshold value k, the process returns to S1 and the same process is repeated.
Hereinafter, the contents of each process will be described in more detail.

［受光出力入力処理］
受光出力入力処理の内容を、図３及び図５に基づいて説明する。
受光出力入力処理は、図３（ｃ）に示すように、液晶シャッタ１５を閉じ（Ｓ１１）、ＬＥＤ１１を発光し（Ｓ１２）、ＰＤ１３で得られた現在受光出力Ａを入力し（Ｓ１３）、入力した現在受光出力ＡをＲＡＭ２１に格納する（Ｓ１４）。次に、図３（ｄ）に示すように、液晶シャッタ１５を開放して（Ｓ１５）、ＬＥＤ１１を発光し（Ｓ１６）、現在受光出力Ｂを入力し（Ｓ１７）、入力した現在受光出力ＢをＲＡＭ２１に格納する（Ｓ１８）。
ＰＤ１３が経年による埃の堆積の増加、あるいは温度の上昇による影響を受けている場合には、現在受光出力Ａは、これらノイズ源の影響により、設置当初の基準受光出力Ａ（20mV）よりも低下して、例えば10mVとなる。・・・・（１）
ここで、検煙空間５に煙が存在しない場合であって、上記（１）と同様に、ＰＤ１３が経年による埃の堆積、あるいは温度による影響を受けている場合には、現在受光出力Ｂは、これらノイズ源の影響により、設置当初の基準受光出力Ｂ（120mV）よりも上記（１）と同様の割合で低下して、60mVとなる。・・・・（２）
他方、検煙空間５に煙が存在する場合であって、上記（１）と同様に、ＰＤ１３が経年による埃の堆積、あるいは温度による影響を受けている場合には、現在受光出力Ｂは、上記（２）と同様なノイズ源の影響に加えて、煙の影響により、上記（２）の出力よりも更に低下して、例えば30mVとなる。・・・・（３） [Light reception output input processing]
The contents of the light reception output input process will be described with reference to FIGS.
In the light reception output input process, as shown in FIG. 3C, the liquid crystal shutter 15 is closed (S11), the LED 11 emits light (S12), and the current light reception output A obtained by the PD 13 is input (S13). The currently received light output A is stored in the RAM 21 (S14). Next, as shown in FIG. 3D, the liquid crystal shutter 15 is opened (S15), the LED 11 emits light (S16), the current received light output B is input (S17), and the input current received light output B is obtained. The data is stored in the RAM 21 (S18).
When the PD 13 is affected by an increase in dust accumulation due to aging or an increase in temperature, the current light reception output A is lower than the reference light reception output A (20 mV) at the beginning of installation due to the influence of these noise sources. For example, 10 mV. (1)
Here, when there is no smoke in the smoke detection space 5 and the PD 13 is affected by accumulation of dust or temperature due to aging, as in (1) above, the current light receiving output B is Due to the influence of these noise sources, the reference light receiving output B (120 mV) at the beginning of installation is reduced at a rate similar to the above (1) to 60 mV. (2)
On the other hand, when smoke is present in the smoke detection space 5 and the PD 13 is affected by accumulation of dust or temperature due to aging, as in (1) above, the current received light output B is In addition to the influence of the noise source similar to the above (2), due to the influence of smoke, the output is further reduced from the output of the above (2) to 30 mV, for example. .... (3)

なお、ＰＤ１３が経年による埃の堆積、あるいは温度による影響を受けている場合とは、設置当初と比較して、埃の堆積が増加または減少しているか、あるいは温度が上昇または低下しているかということであって、上記のとおり、埃の堆積が増加あるいは温度が上昇している場合は、これらノイズ源の影響により、上記（１）、（２）および（３）の現在受光出力Ａ又はＢは、対応する設置当初の基準受光出力Ａ又はＢよりも低下する。一方、埃の堆積が減少あるいは温度が低下している場合は、これらノイズ源の影響により、上記（１）、（２）および（３）の現在受光出力Ａ又はＢは、対応する設置当初の基準受光出力Ａ又はＢよりも増加する。また、温度の影響による現在受光出力Ａ又はＢの変化は、ＰＤ１３の受光量の温度特性だけに限らず、ＬＥＤ１１の発光量の温度特性も加味された出力変化となる。   Note that when the PD 13 is affected by dust accumulation or temperature due to aging, whether dust accumulation has increased or decreased, or temperature has increased or decreased compared to the initial installation. In other words, as described above, when the accumulation of dust increases or the temperature rises, the current received light output A or B of (1), (2), and (3) above due to the influence of these noise sources. Is lower than the corresponding reference light reception output A or B at the beginning of installation. On the other hand, when the accumulation of dust is reduced or the temperature is lowered, the current light receiving output A or B of the above (1), (2) and (3) is caused by the influence of these noise sources. More than the reference light receiving output A or B. Further, the change in the current light reception output A or B due to the influence of temperature is not limited to the temperature characteristic of the light reception amount of the PD 13 but also the output change taking into account the temperature characteristic of the light emission amount of the LED 11.

なお、図３（ｃ）、図３（ｄ）において、検煙空間５に煙が存在する状態を示しているが、これは受光出力入力処理が検煙空間５に煙が存在する状態でのみ行われることを意味するのではなく、煙が存在する状態であってもよいことを強調したためである。したがって、受光出力入力処理は、検煙空間５における煙の存在の有無に拘わらず行なわれる。   3 (c) and 3 (d) show a state in which smoke is present in the smoke detection space 5, but this is only when the light receiving output input process is in a state in which smoke is present in the smoke detection space 5. It is not meant to be done, but to emphasize that smoke may be present. Therefore, the light reception output input process is performed regardless of the presence or absence of smoke in the smoke detection space 5.

［出力変化率算出］
出力変化率算出の処理の内容を図６に基づいて説明する。
出力変化率算出は、基準受光出力Ａと現在受光出力Ａに基づいて出力変化率を算出する処理である。具体的には、基準値取得動作によってＲＡＭ２１に格納されている基準受光出力Ａ及び受光出力入力処理（Ｓ１）によってＲＡＭ２１に格納された現在受光出力Ａに基づいて、出力変化率α＝（現在受光出力Ａ）/（基準受光出力Ａ）を算出し（Ｓ２１）、算出した出力変化率αをＲＡＭ２１に格納する（Ｓ２２）。
例えば、現在受光出力Ａ＝10mV、基準受光出力Ａ＝20mVとすれば、出力変化率α＝10/20＝0.5となる。 [Output change rate calculation]
The content of the output change rate calculation process will be described with reference to FIG.
The output change rate calculation is a process of calculating the output change rate based on the reference light reception output A and the current light reception output A. Specifically, based on the reference light reception output A stored in the RAM 21 by the reference value acquisition operation and the current light reception output A stored in the RAM 21 by the light reception output input process (S1), the output change rate α = (current light reception Output A) / (reference light reception output A) is calculated (S21), and the calculated output change rate α is stored in the RAM 21 (S22).
For example, if the current light receiving output A = 10 mV and the reference light receiving output A = 20 mV, the output change rate α = 10/20 = 0.5.

［補正処理］
補正処理は、出力変化率に基づいて、検煙用光路７のみを通過したときの基準受光出力（基準受光出力Ｂ−基準受光出力Ａ）を、現在受光出力Ｂと同様のノイズ源発生状態にあるとき（例えば出力Ｂと同時期）に、検煙空間５に煙が存在しない状態において検煙用光路７のみを光が通過したときに得られるであろう現在受光出力Ｃに補正する処理である。
具体的には、基準値取得動作によってＲＡＭ２１に格納されている基準受光出力Ａ、Ｂを読み出して、現在受光出力Ｃ＝（基準受光出力Ｂ−基準受光出力Ａ）×出力変化率αを算出し（Ｓ３１）、算出した現在受光出力ＣをＲＡＭ２１に格納する（Ｓ３２）。
例えば、基準受光出力Ｂ＝120mV、基準受光出力Ａ＝20mV、出力変化率α＝0.5とすれば、現在受光出力Ｃ＝（120-20）×0.5＝50mVとなる。 [Correction process]
In the correction processing, based on the output change rate, the reference light reception output (reference light reception output B−reference light reception output A) when only passing through the smoke detection optical path 7 is changed to the same noise source generation state as the current light reception output B. At a certain time (for example, at the same time as the output B), a process for correcting the current received light output C that would be obtained when light passed through only the smoke detection optical path 7 in a state where no smoke exists in the smoke detection space 5 is there.
Specifically, the reference light reception outputs A and B stored in the RAM 21 are read out by the reference value acquisition operation, and the current light reception output C = (reference light reception output B−reference light reception output A) × output change rate α is calculated. (S31) The calculated current light reception output C is stored in the RAM 21 (S32).
For example, if the reference light receiving output B = 120 mV, the reference light receiving output A = 20 mV, and the output change rate α = 0.5, the current light receiving output C = (120-20) × 0.5 = 50 mV.

［減光率ｄの算出］
減光率ｄは、受光出力入力処理（Ｓ１）によってＲＡＭ２１に格納されている現在受光出力Ａ、Ｂ及び補正処理（Ｓ３）によって得られた現在受光出力Ｃに基づいて、減光率ｄ［％］＝｛1-（現在受光出力Ｂ−現在受光出力Ａ）/Ｃ｝×100によって求め（Ｓ４１）、求めた減光率ｄをＲＡＭ２１に格納する（Ｓ４２）。
例えば、検煙空間５に煙が存在しない場合には、現在受光出力Ｂは前述のように例えば60mVとなる。また、現在受光出力Ａは、前述のように例えば10mVとなる。
したがって、この場合の減光率ｄは、減光率ｄ＝｛1-（60−10）/50｝×100＝０［％］となる。これは、検煙空間５に煙が存在しないという状態に一致している。
この場合、Ｓ５の判断においては、減光率ｄが閾値を超えないので、火災信号を送出しない（図４参照）。 [Calculation of light attenuation rate d]
The light attenuation rate d is based on the current light reception outputs A and B stored in the RAM 21 by the light reception output input process (S1) and the current light reception output C obtained by the correction process (S3). ] = {1− (current received light output B−current received light output A) / C} × 100 (S41), and the obtained light attenuation rate d is stored in the RAM 21 (S42).
For example, when no smoke is present in the smoke detection space 5, the current light receiving output B is, for example, 60 mV as described above. Further, the current light receiving output A is, for example, 10 mV as described above.
Therefore, the dimming rate d in this case is dimming rate d = {1− (60−10) / 50} × 100 = 0 [%]. This coincides with a state in which no smoke exists in the smoke detection space 5.
In this case, in the determination of S5, since the light attenuation rate d does not exceed the threshold value, a fire signal is not sent (see FIG. 4).

他方、検煙空間５に煙が存在する場合には、現在受光出力Ｂは前述のように例えば30mVとなる。また、現在受光出力Ａは、煙の存在の有無によっては変化しないので、上記の検煙空間５に煙が存在しない場合と同様に、例えば10mVとなる。
したがって、この場合の減光率ｄは、減光率ｄ＝｛1-（30−10）/50｝×100＝60［％］となる。これは、検煙空間５に煙が存在するという状態に一致している。
この場合、Ｓ５の判断においては、減光率ｄが閾値ｋ（例えば、10％）を超えることになるので、火災信号を送出する（図４参照）。 On the other hand, when smoke is present in the smoke detection space 5, the current light receiving output B is, for example, 30 mV as described above. Further, since the current light reception output A does not change depending on the presence or absence of smoke, it is, for example, 10 mV as in the case where no smoke is present in the smoke detection space 5 described above.
Accordingly, the dimming rate d in this case is dimming rate d = {1− (30−10) / 50} × 100 = 60 [%]. This coincides with the state in which smoke is present in the smoke detection space 5.
In this case, in the determination of S5, since the light attenuation rate d exceeds a threshold value k (for example, 10%), a fire signal is transmitted (see FIG. 4).

以上のように、本実施の形態の減光式煙感知器１によれば、受光素子として単一のＰＤ１３を用い、しかも火災判別動作を行うときに、基準受光出力Ａと現在受光出力Ａとに基づいて、ＰＤ１３の出力変化率を求め、出力変化率に基づいてＰＤ１３の出力値（基準受光出力Ｂ−基準受光出力Ａ）を補正するようにしているので、ＰＤ１３の例えば温度や埃の堆積等に起因する出力値の変化（ノイズの影響）を精度良く補償することができ、正確な火災判別を行うことができる。また、受光素子として単一のＰＤ１３を用いているので、従来例で示した２つの受光素子を用いた場合のように、分離配設されることに起因する受光量の差異も生じることがなく、また、個体間の特性のバラツキも生じない。   As described above, according to the dimming smoke detector 1 of the present embodiment, when the single PD 13 is used as the light receiving element and the fire discrimination operation is performed, the reference light receiving output A, the current light receiving output A, and Therefore, the output change rate of the PD 13 is obtained and the output value of the PD 13 (reference light reception output B−reference light reception output A) is corrected based on the output change rate. It is possible to accurately compensate for the change in output value (effect of noise) caused by the above, and to perform accurate fire discrimination. Further, since a single PD 13 is used as the light receiving element, there is no difference in the amount of light received due to the separate arrangement as in the case of using the two light receiving elements shown in the conventional example. Also, there is no variation in characteristics between individuals.

上記実施の形態においては、上記「煙なしの受光出力」（基準受光出力Ｂと基準受光出力Ａとの差分の値）と上記ＰＤ１３の出力変化率とに基づいて、上記「煙なしの受光出力」を、前記現在受光出力Ｂ（監視状態）と同様のノイズ源発生状態にあるときの現在受光出力Ｃ（補正基準値）に補正した。そして、当該現在受光出力Ｃ（補正基準値）と、現在受光出力Ｂ（第二の監視値）と現在受光出力Ａ（第一の監視値）との差分の値と、に基づいて、減光率を算出して火災の判別を行った。
しかしながら、上記「煙なしの出力」の代わりに上記「煙ありの出力」についてノイズ源に関する補正を行うようにして、これを用いて火災判別を行うようにすることもできる。つまり、上記「煙ありの受光出力」（現在受光出力Ｂと現在受光出力Ａとの差分の値）と上記ＰＤ１３の出力変化率とに基づいて、上記「煙ありの受光出力」を、前記基準受光出力Ｂ（基準状態）と同様のノイズ源発生状態にあるときの基準受光出力Ｃ（補正監視値）に補正する。そして、当該基準受光出力Ｃ（補正監視値）と、基準受光出力Ｂ（第二の基準値）と基準受光出力Ａ（第一の基準値）との差分の値と、に基づいて、減光率を算出して火災の判別を行うこともできる。
また、減光率を用いて火災を判別したが、煙濃度などを用いて火災判別を行ってもよい。
また、前記実施の形態において、基準状態として、減光式煙感知器１を設置した当初の状態で説明したが、これに限定されず、所定期間の現在受光出力ＡおよびＢの移動平均値を基準受光出力ＡおよびＢとするなど、公知の平均化処理などにより、基準受光出力ＡおよびＢとしてもよい。 In the above embodiment, based on the “light receiving output without smoke” (the difference value between the reference light receiving output B and the reference light receiving output A) and the output change rate of the PD 13, the “light receiving output without smoke” is used. Is corrected to the current light reception output C (correction reference value) when the noise source generation state is the same as the current light reception output B (monitoring state). Based on the current light reception output C (correction reference value) and the difference value between the current light reception output B (second monitoring value) and the current light reception output A (first monitoring value), the light is dimmed. The fire was determined by calculating the rate.
However, instead of the “output without smoke”, the noise output may be corrected for the “output with smoke”, and this may be used for fire discrimination. That is, based on the “light reception output with smoke” (the difference value between the current light reception output B and the current light reception output A) and the output change rate of the PD 13, the “light reception output with smoke” is determined as the reference. Correction is made to the reference light reception output C (correction monitoring value) when the noise source generation state is the same as the light reception output B (reference state). Based on the reference light reception output C (correction monitoring value) and the difference value between the reference light reception output B (second reference value) and the reference light reception output A (first reference value), the light is dimmed. It is also possible to determine the fire by calculating the rate.
Moreover, although the fire was determined using the light attenuation rate, the fire may be determined using the smoke density or the like.
Moreover, in the said embodiment, although demonstrated in the initial state which installed the dimming smoke detector 1 as a reference | standard state, it is not limited to this, The moving average value of the present light reception output A and B of a predetermined period is used. The reference light reception outputs A and B may be obtained by a known averaging process such as reference light reception outputs A and B.

なお、上記の実施の形態では、シャッタ手段の例として液晶シャッタ１５を例に挙げて説明したが、本発明のシャッタ手段は液晶シャッタ１５に限定されるものではなく、光の投光と遮光を瞬時に切り換えることができるシャッタであれば、他の形態のものであってもよい。   In the above-described embodiment, the liquid crystal shutter 15 has been described as an example of the shutter unit. However, the shutter unit of the present invention is not limited to the liquid crystal shutter 15 and can project and block light. Other shutters may be used as long as they can be switched instantaneously.

１ 減光式煙感知器
３ 筐体
４ 開口部
５ 検煙空間
６ 隔壁
６ａ ＬＥＤ用窓
６ｂ ＰＤ用窓
７ 検煙用光路
９ 補償用光路
１１ ＬＥＤ
１３ ＰＤ
１５ 液晶シャッタ
１７ ＭＰＵ
１７ａ 火災判別手段
１７ｂ 発光制御手段
１７ｃ 液晶シャッタ制御手段
１９ ＲＯＭ
２１ ＲＡＭ
２３ 回路基板
２５ 送受信回路
２７ ライトガイド
２９ 発光制御回路
３１ 受光増幅回路
３３ 火災受信機 DESCRIPTION OF SYMBOLS 1 Dimming type smoke detector 3 Housing | casing 4 Opening part 5 Smoke detection space 6 Partition 6a LED window 6b PD window 7 Smoke light path 9 Compensation light path 11 LED
13 PD
15 Liquid crystal shutter 17 MPU
17a Fire discrimination means 17b Light emission control means 17c Liquid crystal shutter control means 19 ROM
21 RAM
23 circuit board 25 transmission / reception circuit 27 light guide 29 light emission control circuit 31 light reception amplification circuit 33 fire receiver

Claims (5)

煙が流入する検煙空間と、該検煙空間を横断するように形成された検煙用光路と、前記検煙空間とは分離して設けられた補償用光路と、前記検煙用光路及び前記補償用光路に向けて発光する発光素子と、前記検煙用光路及び前記補償用光路を通過した光を受光可能に配設された受光素子と、前記検煙用光路に設けられて該検煙用光路を通過する光の遮光と透光を切り換えるシャッタ手段と、基準状態において前記シャッタ手段によって前記検煙用光路を遮光及び透光して前記受光素子によって受光された受光量を第一及び第二の基準値とし、また、監視状態において前記シャッタ手段によって前記検煙用光路を遮光及び透光して前記受光素子によって受光された受光量を第一及び第二の監視値とし、
前記第一の基準値と第一の監視値とに基づいて前記受光素子の受光量の変化率を求め、
当該変化率と前記第二の基準値と第一及び第二の監視値とに基づいて火災の判別を行う火災判別手段とを備えたことを特徴とする減光式煙感知器。 A smoke detection space into which smoke flows, a smoke detection optical path formed so as to cross the smoke detection space, a compensation optical path provided separately from the smoke detection space, the smoke detection optical path, and A light emitting element that emits light toward the compensation optical path, a light receiving element that is disposed so as to be able to receive light that has passed through the smoke detection optical path and the compensation optical path, and a sensor that is provided in the smoke detection optical path. Shutter means for switching between shielding and transmitting light passing through the smoke optical path, and the amount of received light received by the light receiving element by shielding and transmitting the smoke detecting optical path by the shutter means in the reference state. The second reference value, and the amount of light received by the light receiving element by blocking and transmitting the light path for smoke detection by the shutter means in the monitoring state as the first and second monitoring values,
Based on the first reference value and the first monitoring value, to determine the rate of change in the amount of light received by the light receiving element,
A dimming smoke detector, comprising: a fire discriminating means for discriminating a fire based on the rate of change, the second reference value, and the first and second monitoring values. 前記火災判別手段は、
前記第二の基準値と第一の基準値との差分の値と、前記変化率とに基づいて、前記差分の値を、前記監視状態と同様のノイズ源発生状態にあるときの補正基準値に補正し、
当該補正基準値と、前記第二の監視値と第一の監視値との差分の値と、に基づいて火災の判別を行うことを特徴とする請求項１記載の減光式煙感知器。 The fire discrimination means is
Based on the difference value between the second reference value and the first reference value and the rate of change, the difference value is a correction reference value when the noise source is in the same state as the monitoring state. To
The dimming smoke detector according to claim 1, wherein the fire is determined based on the correction reference value and a difference value between the second monitoring value and the first monitoring value. 前記火災判別手段は、
前記第二の監視値と第一の監視値との差分の値と、前記変化率とに基づいて、前記第二の監視値と第一の監視値との差分の値を、前記基準状態と同様のノイズ源発生状態にあるときの補正監視値に補正し、
前記第二の基準値と第一の基準値との差分の値と、当該補正監視値とに基づいて火災の判別を行うことを特徴とする請求項１記載の減光式煙感知器。 The fire discrimination means is
Based on the difference value between the second monitoring value and the first monitoring value and the change rate, the difference value between the second monitoring value and the first monitoring value is set to the reference state. Correct it to the correction monitoring value when it is in the same noise source generation state,
The dimming smoke detector according to claim 1, wherein fire is determined based on a difference value between the second reference value and the first reference value and the corrected monitoring value. 前記補償用光路は、ライトガイドによって構成されていることを特徴とする請求項１〜３のいずれか一項に記載の減光式煙感知器。   The dimming smoke detector according to claim 1, wherein the compensation optical path is configured by a light guide. 前記火災判別手段は、受光量に基づいて減光率を演算し、該減光率に基づいて火災の判別を行うことを特徴とする請求項１〜４のいずれか一項に記載の減光式煙感知器。   5. The light attenuation according to claim 1, wherein the fire determination unit calculates a light attenuation rate based on a light reception amount, and performs a fire determination based on the light attenuation rate. Smoke detector.

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