JPH04365195A - Flame detector - Google Patents

Abstract

PURPOSE:To lower the failure rate of a light receiving device, etc., and to improve the reliability of a gas turbine by transmitting a flame state to the optical sensor of the light receiving device through an optical fiber in the flame detection of the gas combustion chamber of the gas turbine, etc. CONSTITUTION:A light emission window 3 is installed near to a burner 2 and on the wall of the combustion chamber 1. The flame state in the combustion chamber 1 made incident by the condenser lens 5 of a condenser head 4 through the light emission window 3 is sent to the optical sensor 9 in the light receiving device 8 through the optical fiber 7, and is converted into a current. Here, the rays of light of bands different from each other in wavelengthes are detected by two optical sensors 9, and are inputted to a flame discrimination circuit 11 through pre-amplifiers 10. The flame discrimination circuit 11 compares a preset threshold to be the standard of flame discrimination with an electric signals from the pre-amplifiers 10, and outputs a discriminant signal, and controls a relay circuit 12. Thus, the failure rate of the light receiving device apt to be influenced by vibration or temperature, etc., is remarkably lowered, and the reliability of the gas turbine is improved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame detection device for monitoring the combustion state of a gas combustion chamber of a gas turbine or the like.

0002

2. Description of the Related Art A gas turbine is a prime mover that burns fuel in a combustion chamber and causes the high-temperature gas to act on a turbine to rotate an axle, so the quality of combustion is an important factor.

The combustion chamber is said to be the most difficult part to explain theoretically among the components of a gas turbine.
Because it is complex and involves heat transfer, flow, and chemical reactions, it is designed based on experimental results. The necessary conditions for a combustion chamber are high combustion efficiency, low pressure loss, stable pressure, temperature, and ratio of fuel and air to enable good combustion, and constant temperature at the exit of the combustion chamber. There are certain things.

For this reason, the flame condition of the burner in the combustion chamber is constantly monitored by a flame detector, and a signal generated by the detector is relayed and distributed to each control system.

[0005] Conventional flame detectors are made in foreign countries and have glass fitted to the tip of a steel outer cylinder and a discharge tube (vacuum tube) built into the cylinder. Room 1
It was attached directly to the wall near burner 2 with the glass surface facing into the combustion chamber.

There are two electrodes in the discharge tube, and a voltage is applied between them. When ultraviolet rays emitted from the flame of burner 2 are projected onto these electrodes, a discharge occurs between the two electrodes. Capturing the change in state and sending a signal to the relay circuit 12,
Furthermore, it was sending messages to each control system.

[0007]

[Problems to be Solved by the Invention] Conventional flame detectors have a high failure rate because they are used in harsh environments where combustion chamber vibrations, high temperatures, etc. are transmitted, and it is a factor that reduces the reliability of gas turbines. They had become one.

[0008] Furthermore, since this flame detector was made in a foreign country, it was not possible to improve the parts that frequently failed, and it was also not possible to replace parts.

The present invention has been made to solve the above problems.

0010

[Means for Solving the Problems] The flame detection device of the present invention includes a light emitting window provided near the burner on the wall of a combustion chamber, and a condensing head having a condensing lens provided at its tip facing the light emitting window. , an optical fiber whose one end is connected to the rear end of the condensing head, an optical sensor connected to the other end of the optical fiber, and a light receiver having a preamplifier, a flame discrimination circuit, and a relay circuit connected in sequence to the optical sensor. It is characterized by the fact that it is equipped with

[0011]

[Operation] In the above, the flame inside the combustion chamber enters the condensing lens of the condensing head through the light emitting window, is received by the optical sensor of the receiver through the optical fiber, is converted into an electrical signal, and is amplified by the preamplifier. , is input to the flame discrimination circuit.

[0012] The flame discrimination circuit has a threshold value set in advance as a reference for flame discrimination, and when an electric signal is input from the preamplifier, it compares it with the above threshold value to discriminate the flame state. and outputs a discrimination signal to the relay circuit,
The relay circuit outputs control signals to each control system.

[0013] As a result of the above, the condensing head and the light receiver are connected by an optical fiber, and the light receiver, which is susceptible to the vibrations and temperature of the combustion chamber, can be installed at a position away from the combustion chamber, so the failure rate is significantly reduced. This makes it possible to improve the reliability of gas turbines, etc.

[0014]

[Embodiment] An embodiment of the present invention will be explained based on FIG. The present embodiment shown in FIG. 1 is arranged near a light-emitting window 3 provided close to a burner 2 attached to the wall of a combustion chamber 1, has a condensing lens 5 at its tip, and has a heat-resistant section at the rear. 6, an optical fiber 7 having one end connected to the heat-resistant part 6 at the rear of the focusing head 4, and the other end of the optical fiber 7 being divided into two parts and connected to each other at a location away from the combustion chamber 1. The light receiver 8 is equipped with two optical sensors 9 to which the other ends of the divided optical fibers 7 are connected, and two optical sensors 9 to which the two optical sensors 9 are connected, respectively. A flame discrimination circuit 11 to which the two preamplifiers 10 are connected, and a relay circuit 12 to which the flame discrimination circuit 11 is connected are built-in.

In the above, the state of the flame in the combustion chamber 1 that enters the condensing lens 5 of the condensing head 4 through the light emitting window 3 is transmitted to the optical sensor 9 in the light receiver 8 via the optical fiber 7.
is sent to and converted into electric current. Here, the flame state sent through the optical fiber 7 is received by two optical sensors 9, but each optical sensor 9 detects light in a band with a different wavelength, and each output signal is This is to ensure that the target flame is detected by weighting the target flame.

The electrical signal output from the optical sensor 9 is amplified by a preamplifier 10 and then input to a flame discrimination circuit 11. This flame discrimination circuit 11 has a threshold value set in advance as a reference for flame discrimination.
1 receives an electric signal from the preamplifier 10, compares it with the threshold value, determines the flame state, and outputs a determination signal.

The discrimination signal output by the flame discrimination circuit 11 is input to a relay circuit 12, which outputs contact signals for respective control to each control system.

[0018] As a result of the above, the converging head and the light receiver are connected by an optical fiber, and the light receiver, which is susceptible to the vibrations and temperature of the combustion chamber, can be installed at a position away from the combustion chamber, so the failure rate is significantly reduced. This has made it possible to reduce the amount of gas and improve the reliability of the gas turbine.

[0019]

[Effects of the Invention] In the flame detection device of the present invention, the state of the flame inside the combustion chamber, which the condensing head enters through the light emitting window, is sent to the receiver via the optical fiber, converted into an electrical signal by the optical sensor, and then sent to the preamplifier. The flame is amplified and compared with a threshold value in the flame discrimination circuit to discriminate the flame.The discrimination signal is sent to the relay circuit, and the condensing head and receiver are connected by optical fiber to eliminate the effects of vibrations, temperature, etc. in the combustion chamber. Since the light receiver, which is susceptible to light, can be installed at a location away from the combustion chamber, the failure rate is significantly reduced, making it possible to improve the reliability of gas turbines and the like.

[Brief explanation of drawings]

FIG. 1 is a system diagram of a flame detection device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a conventional flame detector.

[Explanation of symbols]

1 Combustion chamber 2 Burner 3. Luminous window 4. Focusing head 5 Condensing lens 7 Optical fiber 8 Photo receiver 9. Light sensor 10 Preamplifier 11 Flame discrimination circuit 12 Relay circuit

Claims (1)

[Claims] Claim 1: A light-emitting window provided near the burner on the wall of the combustion chamber, a condensing head having a condensing lens at its tip facing the light-emitting window, and one end connected to the rear end of the condensing head. 1. A flame detection device comprising: an optical fiber, a light sensor connected to the other end of the optical fiber, a preamplifier connected to the light sensor in sequence, a light receiver having a flame discrimination circuit, and a relay circuit.