JPS60207814A - Pulse burner - Google Patents

Abstract

PURPOSE:To obtain the titled burner capable of detecting the burning condition thereof easily and properly without paying consideration on the heat resistance of a detector and without undergoing restriction on the installation position of the detector. CONSTITUTION:In a combustion chamber 3, air supplied through an air pipe 1 is mixed with a fuel supplied through a gas pipe 4. The gaseous mixture thus produced is exploded by sparks of an ignition plug 8, and pulse combustion is started. Upon this occasion, discrimination between a normal pulse combustion and a continuous combustion. If the continuous combustion is decided, a control part 11 closes an electromagnetic valve 5 to stop the operation. If the normal combustion is decided, the pulse combustion is thereafter continued by a suction operation due to a negative pressure at the time of exhaustion, a fuel absorbing operation and an igniting operation due to heat of a combustion gas partly fed back to the combustion chamber 3 from the tail pipe 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a pulse combustion machine that mixes intake air and fuel, performs pulse combustion, and directly utilizes the combustion reaction heat.

[Technical background of the invention]

In recent years, there has been an extremely high level of energy conservation awareness not only in the industrial world but also in home appliances, and there is an increasing demand for higher efficiency in household heat sources. In order to meet these demands, a pulse combustion engine that applies a pulse jet to combustion and directly utilizes the combustion reaction heat has been developed and is being put into practical use.

At the start of operation, air is sucked in by a startup fan, the sucked air is mixed with fuel that is being pumped in, and combustion is started by causing the mixture to explode with a spark from a spark plug. After that, the operation of the startup fan and the spark plug are stopped, but pulse combustion takes place due to the intake action and fuel suction action due to the negative pressure of the exhaust gas after the explosion, and the ignition action due to the heat of the combustion gas partially returned to the combustion chamber. This will continue.

By the way, in such a pulse combustion machine, depending on the shape and arrangement of the combustion chamber, air and fuel are continuously sucked in due to the draft effect of the flame. Continuous combustion (not combustion) may occur, and the supply balance between air and fuel may be disrupted, leading to deterioration of combustion.

Therefore, a flame detector such as a flame rod that detects flame current is installed in the combustion chamber, or a CdS that detects flame light is installed around the combustion chamber to detect continuous combustion. Some are designed to immediately stop operation, in other words, to prevent continuous combustion and improve combustibility.

[Problems with background technology]

However, when installing a flame detector inside the combustion chamber such as a flame rod, it is necessary to select a flame detector that has sufficient heat resistance against the high temperature of combustion gas, which increases costs. There was a drawback.

Furthermore, when CdS is used, the CdS must be installed at a location where the flame light can be reliably captured, which has the disadvantage that the installation locations are restricted.

[Purpose of the invention]

This invention was made in view of the above circumstances,
The purpose is to provide a pulse combustion machine that enables easy and accurate detection of the combustion state without considering the heat resistance of the detector or limiting the installation location of the detector. It is in.

[Summary of the invention]

In this invention, a vibration sensor is provided at the combustion center, and the vibration is used to distinguish between normal pulse combustion and continuous combustion, and when continuous combustion occurs, the operation is stopped.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, air passes through an air pipe 1 and an air flapper valve 2 provided in the air pipe 1 to a combustion chamber 2.
to go into. On the other hand, fuel (gas) is supplied to the gas pipe 4 and the electromagnetic on-off valves 5 and 5 installed sequentially in the gas pipe 4. The gas enters the combustion chamber 3 through the flapper valve 6. The air and fuel entering the combustion chamber 3 are mixed and pulse-combusted. The high-temperature, high-pressure combustion gas thus obtained is supplied from the layer pipe 7 to a heat exchanger (not shown), where heat is removed therefrom and then exhausted through an exhaust muffler (not shown). Note that a spark plug 8 is provided in the combustion chamber 3.

Further, a vibration sensor such as a piezoelectric element 10 is disposed in the combustion chamber 3 with a heat shield plate 9 interposed therebetween. This piezoelectric element 10 is
It outputs an electrical signal at a voltage level corresponding to the magnitude of strain caused by vibration. This piezoelectric element 10 and the electromagnetic coil of the electromagnetic on-off valve 5 are connected to a control section 11.

FIG. 2 shows the circuit configuration of the main part of the control section 11.

The output signal of the piezoelectric element 10 is processed by a converter 21,
It is amplified by the amplifier circuit 22, integrated by the integrating circuit 25 made up of a resistor 23 and a capacitor 24, and then supplied to the non-inverting input terminal (+) of the comparator (operational amplifier) 2G. The inverting input (-) of the comparator 26 is supplied with the reference voltage that occurs at the interconnection point of the resistors 27 and 28.

Next, the operation of the above configuration will be explained with reference to FIG.

When the operation start operation is performed, the control unit 11 starts the startup fan (
(not shown) is operated to supply air into the combustion chamber 3 through the flapper valve 2, thereby exhausting unburned gas and the like in the combustion chamber 3, or buripurging. Thereafter, the control unit 11 opens the electromagnetic on-off valve 5 while operating the startup fan to supply fuel to the combustion chamber 3 through the flapper valve 6, and operates the spark plug 8. Then, the supplied air and fuel are mixed in the combustion chamber 3, and the mixture is exploded by the spark from the ignition plug 8. The high-temperature, high-pressure combustion gas generated by this explosion is supplied from the tail pipe 7 to the heat exchanger, where heat is removed and then exhausted. In this case, due to the explosion, positive pressure is generated in the combustion chamber 3 and the flapper valve 2.6 is closed, temporarily stopping the supply of air and fuel. Since negative pressure is generated, the flapper valves 2 and 6 are opened again, and air and fuel are sucked in again. Then, the inhaled air and fuel are mixed 1 and exploded by the spark from the ignition plug 8 in the same manner as described above.

In other words, pulse combustion is started.

At this time, if normal pulse combustion (intermittent combustion) is performed, vibrations are generated due to pressure pulsations in the next firing v3 based on pulse oscillations, and the vibrations are detected by the piezoelectric element 10.

That is, a relatively high voltage signal whose level changes according to the displacement of the vibration is output from the signal processing circuit 21, and the signal is amplified by the amplifier circuit 22 to become the voltage Vl. This voltage 1 is integrated by the integrating circuit 25 to become a flat voltage v2, which is supplied to the comparator 26, where the reference voltage V
compared with ref. In this case, the voltage V2 is the reference voltage V
ref, and therefore the output voltage of the comparator 26 is at a high level. This becomes a determination signal indicating that normal pulse combustion is being performed.

If it is determined that the pulse combustion is normal, the control unit 11
stops the operation of the startup fan and the operation of the spark plug 8, and from then on, the intake action and fuel suction action are performed by the negative pressure during exhaust, and the ignition action is performed by the heat of the combustion gas partially returned from the tail pipe 7 to the combustion chamber 3. and mtis the pulse combustion.

By the way, if continuous combustion occurs due to some cause such as the draft effect of the flame, there will be no pressure pulsation in the combustion chamber 3, and therefore no vibration will occur. At this time, since there is no vibration, no distortion occurs in the piezoelectric element 1o, and the output signal voltage of the signal processing circuit 21 becomes approximately zero level. Therefore, amplifier circuit 2
The output voltage of the comparator 26 becomes V1', which is much lower than the reference voltage V ref, and the output voltage of the comparator 26 becomes a low level. This becomes a determination signal indicating that continuous combustion is being performed.

If it is determined that the combustion is continuous, the control section 11 closes the electromagnetic opening/opening valve 5 and stops the supply of fuel.

In other words, the operation is stopped.

In this way, the pressure around combustion? Since the IK element 10@ is installed and vibration is used to distinguish between normal pulse combustion and continuous combustion, there is no need to consider the heat resistance of the combustion gas to high temperatures as with conventional flame ronds, and Unlike CdS, there are no restrictions on installation locations, and combustion conditions can be detected easily and accurately. Therefore, cost reduction and simplification of the configuration of the combustion chamber 3 are achieved.

In the above example, the pressure N element 10 is provided on the outer peripheral surface of the combustion chamber 3, but it may be provided at other locations such as the tail pipe 7 as long as it is a location where vibrations around the combustion chamber 3 are transmitted. Also,
Although the piezoelectric element 10 is used to capture the displacement of 1i motion, it may also be used to capture, for example, the acceleration or velocity of vibration, and vibration sensors are not limited to piezoelectric elements, but can also be used, such as motion meters, strain meters, and acceleration meters. A meter, microphone, etc. may also be used. In addition, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without changing the gist.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a pulse combustion chamber that enables easy and accurate detection of the combustion state without considering heat resistance or being restricted in the installation location.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a schematic diagram, FIG. 2 is a circuit diagram of the control section, and FIG. 3 is a diagram for explaining the operation. 3... Combustion chamber, 10... Piezoelectric element (vibration sensor),
11...control unit. Applicant's agent Patent attorney Takehiko Suzue Figure 1 i Figure 2 ◆ V Figure 3 B opening □

Claims (2)

[Claims] (1) In a pulse combustion machine that mixes air and fuel and burns them in pulses, a vibration sensor installed at the mouth of the combustion chamber and the output of this vibration sensor are used to distinguish between normal pulse combustion and continuous combustion. 1. A pulse combustion machine, comprising: a means for controlling operation according to a result of the determination. (2) The pulse combustion machine according to claim 1, wherein the vibration sensor detects vibration displacement, photographing acceleration, or photographing speed.