JPH0584405B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a combustion method in which the flame front propagates by continuously repeating the cycles of air supply and exhaust, ignition, combustion, and extinguishing within a tubular combustion chamber. The present invention relates to improvements in combustion devices, and particularly to a propagation combustion device that allows the flame front to propagate back and forth.

[Prior Art] As shown in FIG. 3, a conventional propagation combustion device of this kind, for example, rapidly increases the flow velocity of the flame flow during extinguishing at the proximal extinguishing position A' of the tubular combustion chamber 1'. A constricted part 2' is provided for changing the temperature, and a mixing chamber 3' having one end open on the upstream side of the constricted part 2' is provided, and an ignition heat source 4' is provided at the tip ignition position B'. An exhaust pipe 5' is connected to the downstream side of the ignition heat source 4', and a gas supply nozzle 6' is connected to the proximal end mixing chamber 3', and a primary air intake port 7' is provided around the opening of the gas supply nozzle 6'. It has a structure in which it is inserted in the same way.

[Problem to be solved by the invention] A propagation combustion device uses a combustion method in which a cycle of air supply and exhaust, ignition, combustion, and extinguishing is continuously repeated in a tubular combustion chamber, and the flame front propagates during each cycle of combustion. However, in the conventional propagation combustion apparatus described above, the gas from the gas supply nozzle 6' and the air from the primary air intake port 7' are mixed in the mixing chamber 3', and the mixture is passed from the mixing chamber 3' to the constriction part 2. ' is fed into the tubular combustion chamber 1' and flows from the upstream side to the downstream side, and when the tip of the mixture reaches near the tip ignition position B', it is ignited by the ignition heat source 4'. The air-fuel mixture starts to burn from the tip side, and the flame flow flows from the downstream side to the upstream side within the tubular combustion chamber 1' to perform flame propagation combustion, uniformly heating each part of the tubular combustion chamber 1', and then to the end of the flame flow. When the flame reaches the constricted part 2' at the proximal end, the constricted part 2' creates a barrier to dam the flame flow and rapidly changes the flow velocity to extinguish the flame. The flame propagation combustion operation is continuously repeated in which the combustion exhaust gas from the previous cycle is pushed downstream and released from the exhaust pipe 5' to the outside of the device. However,
During one cycle, the supply of air, that is, the supply and combustion of the air-fuel mixture, that is, propagation combustion, is carried out separately during forward and return times.On the other hand, since it is propagation (only during return), tubular combustion occurs during air supply (onward). As the chamber 1' is cooled, its combustion efficiency decreases, and since the flame is extinguished every cycle, there are problems such as the need for stable extinguishing (including measures to reduce extinguishing noise).

This invention has been made in view of the problems of the prior art,
The object of the present invention is to provide a propagation combustion device that solves the problems of the prior art by causing flame to propagate back and forth without extinguishing it.

[Means for Solving the Problems] In order to achieve the above object, the propagation combustion device according to the present invention continuously repeats the cycle of supplying and exhausting air, ignition, combustion, and extinguishing in the tubular combustion chamber to reduce the flame front. In a propagation combustion apparatus of a combustion type in which flames propagate, the invention of claim 1 provides a flame detection device in which a flame detector is installed in a tubular combustion chamber corresponding to an interval of flame propagation, and a flame detection signal from the flame detector is installed. An arbitrary switching means that can switch to a high-pressure mixture when there is a flame on the gas supply side and to a low-pressure mixture when there is a flame on the gas exhaust side based on this is provided in these mixture supply paths, and the switching means Therefore, the flame is made to propagate back and forth between the flame detectors, and the invention of claim 2 uses a gas with a slow combustion rate in place of the high-pressure mixture of the invention of claim 1, and a low-pressure mixture. The invention of claim 3 uses a gas with a high mixing ratio of gas and air instead of the high-pressure mixture and the gas with a slow combustion speed in the inventions of claims 1 and 2. This is an air-fuel mixture with a low mixing ratio of gas and air instead of a low-pressure air-fuel mixture and a gas with a high combustion rate.

[Function] In the propagation combustion device of the present invention configured as described above, in the invention according to claim 1, the supply of the air-fuel mixture to the combustion chamber has an interval in which the flame propagates within the tubular combustion chamber. When one of the flame detectors installed at the gas supply side detects that there is a flame on the gas supply side, the high-pressure mixture is switched and supplied via the switching means on the high-pressure side that operates based on the detection signal, and the other side When the flame detector detects that there is a flame on the gas exhaust side, the low-pressure air-fuel mixture is switched and supplied via the low-pressure side switching means that operates based on the detection signal, so the flame does not flow between the flame detectors. It burns reliably in both directions without extinguishing it, and propagates in both directions.

In addition, as in the invention described in claim 2, claim 1
In addition to replacing the high-pressure mixture with a gas with a slow combustion rate and replacing the low-pressure mixture with a gas with a high combustion rate in the invention described above, as in the invention described in claim 3, the inventions according to claims 1 and 2 Instead of the high-pressure mixture and gas with a slow burning rate, a mixture with a large gas-to-air mixture ratio is used, and instead of the low-pressure mixture and gas with a high-burning rate, a mixture with a small gas-to-air mixture ratio is used. This allows the flame to reliably propagate back and forth through the flame detector without being extinguished.

[Embodiments] Examples of the propagation combustion apparatus according to the present invention will be described below with reference to the drawings.

In Figures 1 and 2, reference numeral 1 denotes a straight tube-shaped combustion chamber, and a shield wall is created on the upstream side of the combustion chamber, that is, at the base end extinguishing position A, by rapidly changing the flow velocity of the flame flow during extinguishing. A constricted part 2 is provided to ensure that the mixing chamber 3 is opened at one end on the upstream side of the constricted part 2, and a ceramic heater, nichrome wire,
An ignition heat source 4 such as an igniter or a pilot burner is provided, and an exhaust pipe 5 is provided on the downstream side of the ignition heat source 4.
A mixture nozzle 6 is connected to the proximal end mixing chamber 3 through a primary air intake port 7 from its opening to the periphery.
A propagation combustion device is constructed by inserting the following.

In the propagation combustion apparatus having the above configuration, an embodiment of the invention according to claim 1 includes a detector F ₁ such as a flame rod, an optical fiber, etc. for detecting the flame a in the straight tube-shaped combustion chamber 1, as shown in FIG. F ₂ is installed corresponding to the interval at which the flame a propagates (for example, near the downstream side of the narrowed part 2 and near the upstream side of the ignition heat source 4), and the flame detector F ₁ on the gas supply side detects the flame a. When the flame detection signal is detected, the switching means _V1 such as a solenoid valve provided in the high-pressure mixture supply path 8 is switched and operated to supply the high-pressure mixture into the straight pipe combustion chamber 1, When the flame detector F ₂ on the gas exhaust side detects flame a, the switching means V ₂ such as a solenoid valve provided in the mixture supply path 9 on the low pressure side is switched and operated based on the flame detection signal to start low pressure mixing. By supplying air into the straight tube-shaped combustion chamber 1, the flame a
can be propagated back and forth between the flame detectors F ₁ and F ₂ . The mixture supply paths 8 and 9 on the high pressure side and the low pressure side are connected to the mixture nozzle 6.

The invention according to claim 2 is characterized in that, in place of the high-pressure mixture in the invention according to claim 1, a gas with a slow combustion rate,
For example, gases with a CP value around 45, such as propane and butane, and gases with a high combustion rate, such as natural gas, with a CP value of 53, instead of low-pressure mixtures. Gases with a CP value centered around 80, such as hydrogen-based gases, or gases with a CP value centered around 80. Here, the CP value is an experimental index used to express the combustion rate depending on the type of gas.

The invention according to claim 3 uses a mixture with a high mixing ratio of gas and air instead of the high-pressure mixture and the gas with a slow combustion rate in the inventions according to claims 1 and 2.
In addition, instead of a low-pressure mixture and a gas with a high combustion rate, a mixture with a small mixture ratio of gas and air is used. For example, as illustrated in FIG. 2, a gas supply pipe is connected to the mixture nozzle 6. 10 and the air supply pipe 11, the amount of gas supplied from the gas supply pipe 10 is always constant, and the amount of air supplied from the air supply pipe 11 is changed to large or small to increase or decrease the mixing ratio of gas and air. In addition, the amount of air supplied from the air supply pipe 11 is always kept constant, and the amount of gas supplied from the gas supply pipe 10 is switched between large and small amounts to vary the mixing ratio of gas and air.

In the above configuration, the combustion mechanism will be explained next. In the invention according to claim 1, first, at the time of starting, the low pressure side switching means (hereinafter referred to as the low pressure side solenoid valve) _V2 opens and the mixture nozzle 6 When the mixed low-pressure air-fuel mixture is supplied to the mixing chamber 3, and after being sufficiently mixed in the mixing chamber 3, is fed into the straight tubular combustion chamber 1 through the narrowed part 2, the low-pressure air-fuel mixture becomes It flows from the upstream side to the downstream side (right side in the figure) in the straight tube-shaped combustion chamber 1, and its tip reaches the tip ignition position B.
When it reaches close to , it is ignited by the ignition heat source 4, which is always active (for example, red hot) during operation. When the tip of the low-pressure mixture is ignited, the low-pressure mixture starts to burn from the tip, and the flame flow moves inside the straight-tubular combustion chamber 1 from the downstream side to the upstream side (left side in the figure).
When the flame propagation combustion operation is performed and the flame detector _F1 on the gas supply side detects the flame flow, the low pressure side solenoid valve _V2 is closed based on the flame detection signal from the flame detector _F1 . The switching means on the high pressure side (hereinafter referred to as the high pressure side solenoid valve) _V1 is opened to supply the premixed high pressure mixture from the mixture nozzle 6 to the mixing chamber 3, and after sufficiently mixing it in the mixing chamber 3, the narrowed part 2 to the straight-tubular combustion chamber 1, the tip of the high-pressure mixture is ignited at the end of the flame flow of the low-pressure mixture, and the high-pressure mixture flows inside the straight-tubular combustion chamber 1 while burning. A flame propagation combustion operation is performed when the flame flows from the upstream side to the downstream side, and when the flame detector F ₂ on the gas exhaust side detects _the flame flow, the high pressure side electromagnetic At the same time as closing the valve V ₁ , the low-pressure side solenoid valve V ₂ is opened to supply a low-pressure mixture into the straight-tubular combustion chamber 1, and the low-pressure mixture flows downstream in the straight-tubular combustion chamber 1 to its tip. When ignited at the end of the flame flow of the high-pressure air-fuel mixture, flame propagation combustion occurs during the return process based on the above-mentioned principle. In the above-mentioned reciprocating propagation combustion operation, the propagation combustion operation in the past uses a high-pressure mixture, so the amount of heat is large and the flame flow is fast. is small, but the flame flow is slow. Therefore, round-trip propagation is performed in a well-balanced manner. In addition, the ignition of the previous high-pressure mixture from the returning flame flow occurs near the downstream side of the constriction part 2 immediately after the return flame flow passes the flame detector _F1 on the gas supply side. Part 2 is designed to prevent the flame during return from extinguishing unnecessarily before the flame transfers, and the ignition of the low-pressure mixture during return from the previous flame flow is caused by the flame detector on the gas exhaust side. If the ignition heat source 4 is carried out immediately after passing through F ₂ and near the upstream side of the ignition heat source 4, the ignition heat source 4 is required only at the time of starting, and reciprocating propagation combustion is performed automatically thereafter. In addition, when stopping the reciprocating flame propagation combustion, if the supply of the air-fuel mixture is stopped, the flame flow during the final return is reliably extinguished by the change in flow velocity due to the constricted portion 2, and the flame propagation combustion is stopped. In addition, the low-pressure mixture has a small flow rate and is a gas with a concentration that does not cause back-up, so that flame propagation combustion during air supply and return is ensured, while the high-pressure mixture has a large flow rate,
Moreover, since the air flows while being combusted simultaneously with the air supply, and the flame propagation combustion as in the past is reliably performed, there is no problem with the inflow of the low-pressure air-fuel mixture during return.

The invention according to claim 2 supplies a gas with a slow burning rate such as propane or butane type for the flame propagation combustion in the past, and supplies a gas with a fast burning rate like a hydrogen type for the flame propagation combustion in the past. The reciprocating propagation combustion is carried out in the same manner as in the invention set forth in claim 1, and in the invention set forth in claim 3, a mixture with a high mixing ratio of gas and air is supplied to the flame propagation combustion of the past,
Since a gas-air mixture having a low mixing ratio is supplied to the flame propagation combustion during the return process, the reciprocating propagation combustion is carried out in the same manner as in the invention described in claims 1 and 2.

[Effects of the Invention] Since the present invention is configured as described above, it produces the following effects.

The invention according to claim 1 provides a propagation combustion apparatus in which a detector for detecting flame is installed in a tubular combustion chamber corresponding to an interval at which the flame propagates, and gas is supplied based on a flame detection signal from the flame detector. Arbitrary switching means that can switch to high-pressure mixture when there is flame on the gas exhaust side and to low-pressure mixture when there is flame on the gas exhaust side is provided in these mixture supply paths, and the switching means switches the flame to low-pressure mixture when there is flame on the gas exhaust side. Since the flame propagates back and forth between the detectors, there is always a flame inside the tubular combustion chamber, and the flame propagation combustion due to the high pressure mixture in the past and the flame propagation combustion due to the low pressure mixture during the return are well-balanced and continuous. Since the temperature difference (for example, in the range of 95°C to 105°C) is small compared to the conventional one that performs one-way propagation only in the return phase, the combustion efficiency is considerably improved under the same conditions. It is effective when applied to heat sources such as dryers.

The invention set forth in claim 2 is similar to the invention set forth in claim 1 because a gas with a slow combustion speed is supplied for the flame propagation combustion in the past, and a gas with a high combustion speed is supplied for the flame propagation combustion during the return. Reciprocating propagation results in well-balanced combustion and improves combustion efficiency.

The invention according to claim 3 supplies a mixture with a high mixture ratio of gas and air for flame propagation combustion in the past, and supplies a mixture with a low mixture ratio of gas and air for flame propagation combustion in the past. As in the first and second aspects of the invention, the reciprocating propagation is performed in a well-balanced manner and the combustion efficiency is improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the invention according to claims 1 and 2 in the propagation combustion apparatus of the invention,
FIG. 2 is a sectional view showing an embodiment of the invention as claimed in claim 3, and FIG. 3 is a sectional view of a conventional example. 1... Combustion chamber, F ₁ , F ₂ ... Flame detector, V ₁ ,
V ₂ ...Switching means.

Claims (1)

[Scope of Claims] 1. In a combustion type propagation combustion device in which a cycle of supplying and exhausting air, ignition, combustion, and extinguishing is continuously repeated in a tubular combustion chamber 1 and the flame front propagates, the tubular combustion chamber 1 Detector that detects flame inside
F ₁ and F ₂ are installed corresponding to the gap where the flame propagates,
Any switching means capable of switching to a high-pressure mixture when there is flame on the gas supply side and to a low-pressure mixture when there is flame on the gas exhaust side based on flame detection signals from the flame detectors F _{1 and} F 2 V ₁ and V ₂ are provided in these air-fuel mixture supply paths, and by switching the switching means V ₁ and V ₂ , the flame is propagated back and forth between the flame detectors F ₁ and F ₂ . propagation combustion device. 2. A propagation combustion device in which the high-pressure mixture according to claim 1 is replaced with a gas with a slow combustion rate, and the low-pressure mixture is replaced with a gas with a high combustion rate. 3 A mixture with a large mixture ratio of gas and air instead of the high-pressure mixture and gas with a slow combustion rate according to claims 1 and 2; a mixture ratio of gas and air instead of the low-pressure mixture and gas with a high combustion rate; A propagation combustion device with a small mixture of