JPH0445113Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a device for confirming that a light receiver of an ignition detector is operating during its use.

2. Description of the Related Art A photoelectric switch detects whether or not light is incident on a light receiver and outputs this as an electrical signal, and is widely used for detecting the presence or absence of an object.

One of the uses of this photoelectric switch is an ignition detection and alarm device (Japanese Utility Model Publication No. 59-29276).

This device is designed to prevent metal particles mixed into the raw cotton from coming into contact with the outer wall of the duct, or metal pieces coming into contact with each other, causing sparks to be generated. An ignition detector (light receiver) installed in the duct detects the ignition of the raw cotton, etc. of the pressurized material and generates an alarm.
By detecting ignition early with this device, it is possible to minimize the fire within the duct and its spread. This device is indispensable for a device for pumping cotton lumps, etc. using a duct, because the cotton lumps and the like are transported in a duct in a flammable state at high speed, and the rate of fire spread is extremely high.

The ignition detectors 1 are arranged as a group at four locations around the air pressure feeding duct 2, for example, as shown in FIG. 3, and several groups are attached at predetermined intervals in the longitudinal direction of the duct 2. These ignition detectors 1 have a light-receiving element mounted on a base 3 and a wide-angle lens 4 at the tip, and detect light at a predetermined monitoring angle toward the center of the duct.

The output of each ignition detector 1, 1... is processed by a predetermined light reception judgment circuit such as an amplifier, and when light is received, the alarm lamp corresponding to each ignition detector 1, 1... lights up to indicate the ignition location. The buzzer will operate at the same time as the indication. This operation makes it possible to minimize the spread of fire occurring within the duct.

Problems to be Solved by the Invention The above-mentioned ignition detector is intended to prevent the spread of fire, and is required to have particularly high reliability. Therefore, if the functions of the light receiving element, the light reception determining circuit, etc. are degraded or damaged due to an underlying cause, they must be repaired immediately, and are inspected regularly.

Because the ignition detectors are arranged radially toward the center of the duct, this periodic inspection is carried out by inserting your hand through inspection holes scattered throughout the duct.
We had no choice but to adopt the method of igniting a lighter held in our hands and confirming that each alarm lamp and buzzer activated in response, which required a considerable amount of time and effort, and also required us to operate the ducts each time we inspected them. Since it is necessary to stop the process, there is a problem that production efficiency is reduced.

Means for Solving the Problems The self-diagnosis device of the ignition detector of the present invention has a light-receiving element that receives light in the air pressure duct through the light-receiving window, and emits light for self-diagnosis to its own light-receiving element. A plurality of light receivers are arranged on the inner circumferential surface of the duct, each having a light emitting element, and one group having a common field of view is arranged in multiple groups at predetermined intervals in the longitudinal direction of the duct. A scanner that sequentially and repeatedly generates a timing pulse that causes the optical element to instantaneously emit light at a different timing for each of the above-mentioned optical receivers; The present invention is characterized by comprising an ignition determination circuit that determines that ignition has occurred, and a failure determination circuit that is provided for each light receiver and determines that there is a malfunction if the light receiver does not generate a light reception output when its own timing pulse is generated.

Operation The light projecting element provided in each light receiver projects self-diagnosis light toward its own light receiving element at timings that do not overlap with each other according to timing pulses generated by the scanner. When the timing pulse is generated, it is a self-diagnosis period, and the failure determination circuit detects an operational failure. The non-occurrence period of the timing pulse is the firing detection period, during which the firing determination circuit detects firing.
The light receivers are grouped to have a common field of view, and the self-diagnosis periods of the light receivers in each group are staggered from each other, so that ignition detection at each detection location is performed without any downtime.

Example The present invention will be explained below with reference to Examples.

FIG. 1 shows a light receiver 5 of an ignition detector, which is one of the components of the present invention. In the figure, 6 is a case, 7 is a light receiving window into which a transparent plate is fitted, and 8 is a light receiving device such as a phototransistor. 9 is an amplifier for receiving the output of the light receiving element 8; 10 is a light emitting element such as a light emitting diode installed facing the light receiving element at a position that does not obstruct the light receiving path a; 11 is for lighting the light emitting element 10; This switch 11 is an operation confirmation switch attached externally to the light receiver 5. This switch 11 is shown for convenience in explaining the operation of the light receiver 5 alone, and is not a component of the present invention.

The light receivers 5 are disposed in a distributed manner in the duct 2 as described in FIG. 3, with the light receivers 7 directed toward the center thereof. The number of these elements does not necessarily have to be four in one group as in the conventional example explained in Fig. 3, but the required number of elements may be distributed and arranged at appropriate intervals depending on the designed light receiving angle. Good.

This light receiver 5 outputs an ignition detection signal d from an amplifier 9 when a fire or a fire occurs in the duct 2, as in the conventional example explained in FIG. This ignition detection signal d activates an operation confirmation (alarm) lamp, buzzer, etc. (not shown).

Inspection of the light receivers 5 is performed by turning on the operation check switch 11 for each light receiver in turn, and lighting up the light emitting element 10 inside. If the light receiver 5 is performing a normal light receiving operation, a light emission detection signal d is output in response to this, an operation confirmation lamp is lit, and a buzzer is activated. Inspection can be easily carried out by checking this operating state.

The purpose of this invention is to centrally and automatically perform inspection and management using a management device installed in one place, and to continuously detect ignition without overlooking even ignition with a very short luminescence time, while monitoring the light receiver. It is a self-diagnosis of the operating condition. A concrete example of this is shown in FIG.

In the self-diagnosis device 12 shown in FIG. 2, 5 ₁ ,
5 ₂ ... 5 _o is a light receiver, which has a light receiving element 8, an amplifier 9 and a light emitting element 10 built into the case in the same way as shown in Fig. 1, and is connected to the duct 2 as explained in Fig. 3. It is distributed. A scanner 13 receives the clock pulse CL and generates timing signals t ₁ , _{t 2} . 14 ₁ ,
14 ₂ ...14 _o is an inverter circuit for detection, 15
₁ , 15 ₂ ... 15 _o is an AND circuit that is an ignition judgment circuit, 16 ₁ , 16 ₂ ... 16 _o is an inverter circuit for testing, and 17 ₁ , 17 ₂ ... 17 _o is an AND circuit that is a defect judgment circuit. It is.

In the above configuration, the scanner 13 sequentially inspects each of the light receivers 5 ₁ , 5 ₂ . . . 5 _o .

That is, when the scanner 13 is not generating an "H" level timing signal, the "H" level signal inverted by the detection inverter circuits 14 ₁ , 14 ₂ . . . 14 _o is the firing determination circuit.
The AND circuits 15 ₁ , 15 _{2 .} . . 15 _o are made conductive, and the output of the amplifier 9 of each light receiver is passed through the output terminals 18 ₁ , 18 ₂ . . . 18 _o of the firing signal.

Also, the scanner 13 receives timing signals t ₁ , t ₂ . . .
... _to is generated, the detection inverter circuits 14 ₁ , 14 ₂ ...14 _o invert the "L" state.
The level signal is the corresponding firing judgment circuit.
AND circuits 15 ₁ , 15 ₂ ... 15 _o are made non-conductive to prohibit the generation of an alarm, while the timing signals t ₁ , t ₂ ... t _o are the corresponding defect judgment circuits.
AND circuits 17 ₁ , 17 ₂ . . . 17 _o are made conductive. Therefore, upon receiving the timing signal, the light projecting element 10
When the light receiver emitting light is defective and the light reception detection signal a is at the "L" level, the "H" level signal inverted by the test inverter circuits 16 ₁ , 16 ₂ . . . 16 _o is sent to the defect judgment circuit. A certain AND circuit 17 _1,1
7 ₂ ... 17 _o through the test signal output terminal 19 ₁ ,
19 ₂ ... Output from 19 _o as a defective light receiving circuit output.

Output terminals 18 ₁ , 18 ₂ ... 18 for the above firing signal
The ignition detection signal output from _o and the light receiving circuit failure output output from test signal output terminals 19 ₁ , 19 _{2 .} It is transmitted to the alarm means and the circuit failure alarm means. By using these alarm means, it is possible to know the occurrence of ignition in the duct, and also to quickly know if there is a defect in the light receiver. Then, measures to prevent the spread of fire and repair of the light receiver can be taken immediately.

Centralized control using the scanning method described above involves instantaneously inspecting each receiver in sequence while the receiver is in operation.
Moreover, only one receiver is inspected and its detection operation is stopped at each inspection, and the other receivers continue their detection operation, so the ignition detection operation in the duct is not delayed or interrupted. High reliability can be obtained.

Effects of the invention The present invention illuminates the light emitting element in the light receiver of the ignition detector at appropriate timing to create a pseudo light reception state, thereby determining whether or not the light receiver is operating normally. Can be easily confirmed. The amount of light emitted by this light emitting element can always be kept constant,
High reliability is achieved because the brightness does not fluctuate unlike artificial means such as ignition of a lighter.

In particular, the present invention provides a short self-diagnosis period that is sandwiched at a predetermined period within the ignition detection period for each light receiver, and this self-diagnosis period during which ignition cannot be detected is
Since the receivers with a common field of view are prevented from overlapping and there is no detection pause period, automatic inspection work can be performed with high reliability without stopping the operation of the pneumatic delivery duct, increasing the operating rate of the equipment. There is an advantage that it does not deteriorate. Note that since this light projecting element is provided at a position away from the light receiving path, it does not interfere with the original light receiving operation.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a light receiver that is subject to self-diagnosis of the present invention, Figure 2 is a circuit diagram of a self-diagnosis device that is an embodiment of the present invention, and Figure 3 is a conventional example of an ignition detector installed. FIG. 5... Light receiver, 6... Case, 7... Light receiving window,
8... Light receiving element, 9... Amplifier, 10... Light projecting element, a... Light receiving path.

Claims (1)

[Scope of Claim for Utility Model Registration] A light-receiving element that receives light from inside the air pressure duct through a light-receiving window, and a light-emitting element that emits light for self-diagnosis to its own light-receiving element; A plurality of light receivers are arranged in groups having a common field of view at predetermined intervals in the longitudinal direction of the duct, and a timing pulse having a small duty ratio that instantaneously causes the light emitting element to emit light is connected to the light receiver. a scanner that sequentially and repeatedly emits light with shifted timing for each receiver; an ignition determination circuit that is provided for each receiver and determines that the light has fired if a received light output occurs when its own timing pulse is not generated; and each receiver. 1. A self-diagnosis device for an ignition detector, characterized in that it is provided with a failure determination circuit that is provided for each of the detectors and determines that the light receiver is malfunctioning if the light receiver does not generate a received light output when the self-timing pulse is generated.