JPH0330693Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a flame detection device for a propagation combustor that utilizes a gas self-combustion cycle in which a flame repeatedly ignites and extinguishes.

BACKGROUND OF THE INVENTION There is a strong demand for a simple and reliable means for detecting the presence or absence of flame in a propagation combustor.

Problems that the invention aims to solve: Because propagating combustion is a self-combustion cycle of gas in which the flame repeatedly ignites and extinguishes, it is not possible to detect the presence or absence of a flame by simply installing a flame rod in the path of the flame. Furthermore, since the combustion state cannot be directly visually monitored from the outside, there is a problem in detecting it reliably in actual use.

Therefore, this invention is a flame detection device for a propagation combustor that solves the above problems by reliably detecting the presence or absence of flame by combining the detection signal from the flame detector and the activation signal from the timer. The purpose is to provide.

Means for Solving the Problems In order to solve the above problems, this invention proposes a propagation combustion combustion method in which the flame front a is transmitted through the combustion cylinder 1 through the cycle of air supply → ignition → combustion → extinguishing. In the combustor, a flame rod 3 is provided in the passage 2 of the flame front a of the propagation combustor, and the flame detection signal is detected by the logical product of the flame detection signal from the flame detector 3 and the timer operation signal, which is slightly longer than the propagation combustor cycle. They employed technological means designed to detect their presence.

Function When the end of the mixture of gas and air supplied into the combustion tube 1 from its base end reaches near the tip opening of the combustion tube 1, it is ignited by the ignition heater 4, and the flame surface a is ignited by the ignition heater 4. It burns while propagating inside the cylinder 1 toward the base end, and when the flame surface a reaches the base end, it is extinguished, and at the same time as the combustion exhaust gas is released, the air-fuel mixture is supplied for the next propagation combustion. Transition. In the above series of propagation combustion operations, the passage of the flame surface a is detected by the flame detector 3, and the presence or absence of a flame is reliably determined by the logical product of the flame detection by the flame detector 3 and the signal indicating that the timer is operating. Detect. In other words, it is normal when two conditions are satisfied: whether the time-up has occurred within a timer period that is slightly longer than the propagation combustion cycle, and whether the flame has been fired at least once within this condition. , it is abnormal when you are not satisfied. Therefore, when an abnormality is detected, the abnormality is displayed and the combustion operation is immediately stopped to ensure safety.

Embodiment An embodiment of this invention will be described below based on the drawings.

In FIG. 1, reference numeral 1 denotes a straight combustion tube, which has a pressure chamber 5 that also serves as a mixing chamber connected to its base end, and a narrow through hole at the boundary between the pressure chamber 5 and the combustion tube 1, that is, An orifice 6 is provided, and an ignition heater 4 is provided near the opening at the tip of the combustion tube 1. 2
3 is a flame detector provided with a detection part facing the passage 2; 7 is a gas nozzle, and the combustion tube 1 is connected to the opening 5a of the pressure chamber 5;
The fuel gas from the gas nozzle 7 and the combustion air from the opening 5a of the pressure chamber 5 are mixed in the pressure chamber 5, and the mixture is passed through the orifice 6 into the combustion tube 1. Air is now being supplied to the The flame detector 3 is connected to a timer through a so-called microcomputer counting circuit, and detects the presence or absence of a flame by logical product of the flame detection signal from the flame detector 3 and a timer activation signal that is slightly longer than the propagation combustion cycle. (See Figure 2). Here, it is appropriate for the timer times T ₁ , T ₂ . . . to be approximately 1.5 seconds, which is slightly longer than 1 second of the propagation combustor cycle (see Fig. 3).

In the above configuration, propagation combustion occurs when the mixture of fuel gas and combustion air mixed in the base end pressure chamber 5 of the combustion tube 1 is vigorously supplied into the combustion tube 1 via the orifice 6, and the downstream side (first When the end reaches near the tip opening of the combustion tube 1, it is ignited by the ignition heater 4. The flame flow then burns while propagating inside the combustion tube 1 toward the upstream side (see arrow c in FIG. When it reaches the point, it is dammed up and the rapid change in flow velocity ensures that the fire is extinguished, and air is supplied at the same time as the combustion exhaust gas is released. Next, a series of operations to proceed to propagation combustion, that is, a cycle of air supply → ignition → combustion → extinguishing, are automatically repeated at a rate of one second to perform propagation combustion.

In the propagation combustion operation, the presence or absence of a flame is reliably detected by detecting the passage of the flame surface a in the combustion tube 1 by the flame detector 3 and by ANDing both signals while the timer is operating. In other words, there are two conditions: condition A, which is whether the timer has timed up within timer times T ₁ , T ₂ . When A and B are satisfied, it is normal (so-called AND circuit), and when not, it is abnormal. This relationship is shown in detail in Fig. 3, when the timer times T ₁ , T ₂ . . .
1 second, T = 1.5 seconds, so there is at least one flame f within the timer time T ₁ , T ₂ ...
If one is detected, it means normal combustion. That is,
This is because conditions A and B are satisfied. On the other hand, if no flame f is detected within the timer times T ₁ , T ₂ . . . , it means abnormal combustion. That is, this is because conditions A and B are not satisfied. Therefore, when this abnormality occurs, a message to the effect that it is abnormal is immediately displayed, and at the same time, the combustion operation is stopped.

An example of the flame detection operation will be explained in detail based on the flowchart of FIG. 2. Prior to detection, in step 10, the flag F is set to 0, and in step 20, a timer starts measuring time.
If the flame detector detects flame at 30, the step
Go to step 40 and set flag F = 1. If no flame is detected, go to step 50 to determine whether or not time is up.
If after timeout, go to step 60; if flag F = 0, go to step 70 → 80 and display an error and stop; if flag F = 1, it means that flame was detected within the timer setting time. This detection flow is then repeated during combustion, assuming that it is normal.

Effects of the device As explained above, this device has a structure that allows the flame to detect and monitor whether or not propagation combustion is occurring normally, so it is highly safe in actual use. By combining the flame detection signal and the timer activation signal, detection of the presence or absence of the flame can be performed quickly and reliably, eliminating any erroneous operation and ensuring accurate flame detection at all times.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing an example of a propagation combustor, Fig. 2 is a flowchart showing an example of flame detection,
FIG. 3 is a time chart showing the relationship between flame detection and the timer. 1... Combustion tube, a... Flame surface, 2... Passage path,
3...Flame detector.

Claims (1)

[Scope of utility model registration request] In a propagation combustor of a combustion type in which a flame surface a is transmitted through a combustion cylinder 1 under a cycle of air supply → ignition → combustion → extinguishing, a flame detector 3 is installed in a passage 2 of the flame surface a of the propagation combustor. A flame detection device for a propagation combustor, wherein the presence or absence of a flame is detected by the AND of the flame detection signal from the flame detector 3 and a timer activation signal that is slightly longer than the propagation combustion cycle.