JPH0264305A - Combustion device - Google Patents

Abstract

PURPOSE:To enable a small-sized combustion device to be provided and further to enable a sound muffling effect to be improved by a method wherein a first number of acoustic natural vibration determined by a volume of a fuel supplying chamber, a sectional area of a fuel injection hole and its length is made equal to the second number of acoustic natural vibration determined by a volume of a combustion space, a sectional area of a discharging cylinder and a length of a discharging cylinder. CONSTITUTION:A first number of acoustic natural vibration determined by a volume of a combustion space A comprised of an air chamber 1, a burner B, a combustion chamber 2, a heat exchanger 3 and a discharging chamber 4 and the like, a sectional area of a discharging cylinder and a length of the discharging cylinder is set to be equal to the second number of acoustic natural vibration determined by a volume of a fuel supplying chamber 11 at the fuel part for supplying the fuel, a sectional area of a fuel injection hole 9 and a length of the fuel injection hole 9. Due to this fact, the fuel part itself may act as a resonance type sound muffling unit so as to make a remarkable sound muffling effect. In case that the second number of acoustic vibration is difficult to be set due to combustion, a partition unit 12 having some small holes 13 is arranged within the fuel supplying chamber 11 and it can easily be set.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a combustion device that heats water or air by burning fuel, and relates to reducing the noise of the device.

Conventional technology Figure 3 shows a conventional low-noise combustion device, where l is an air chamber and 2
is a combustion chamber, 3 is a heat exchanger, 4 is an exhaust chamber, 5 is an exhaust stack, 6
is a mixture chamber, 7 is a flame port, 8 is a combustion fan, 9 is a fuel injection hole, and 10 is a muffler. The air supplied to the air chamber 2 from the combustion fan 8 and the fuel supplied from the fuel injection hole 9,
Combustion occurs in the combustion chamber 2 using a burner consisting of a mixture chamber 6 that mixes some air and fuel and a lower flame. The combustion gas exchanges heat with water or air in the heat exchanger 3, is muffled by a muffler 10 installed in the exhaust chamber 4, and is then exhausted from the exhaust stack 5.

Problems to be Solved by the Invention In such a conventional device, the muffler 10 is located in the exhaust chamber 4, which makes the device large, and the muffler IO is not located in the combustion chamber 2, where pressure fluctuations are the greatest, so the muffling effect is small. There were other issues.

Means for Solving the Problems In order to solve the above problems, the present invention provides an air chamber supplied with air from a combustion fan, and a burner that combusts the air supplied from the combustion fan and fuel supplied from a fuel nozzle. , the fuel supply in the fuel section with respect to the first acoustic natural frequency determined by the volume of the combustion space consisting of the combustion chamber, the heat exchanger, and the exhaust chamber, the cross-sectional area of the exhaust stack, and the length of the exhaust stack. The second acoustic natural frequency determined by the volume of the chamber, the cross-sectional area of the fuel nozzle, and the length of the fuel nozzle are set to be equivalent.

Air and fuel supplied to the air chamber by the operational combustion fan are combusted in the combustion chamber by a burner consisting of a mixture chamber and a flame port that mix some of the air and fuel.

The combustion gas exchanges heat with water or air in a heat exchanger, is collected in an exhaust chamber, and then exhausted from an exhaust stack. At this time, vibrations are generated by the flame formed at the flame port, and the volume of the combustion space consisting of the air chamber, burner, combustion chamber, heat exchanger, and exhaust chamber, the cross-sectional area of the exhaust stack, and the length of the exhaust stack are Noise having a peak at the determined first acoustic natural frequency is generated.

However, with respect to this first acoustic natural frequency, a second acoustic natural vibration determined by the volume of the fuel supply chamber, the cross-sectional area of the fuel nozzle hole, and the length of the fuel nozzle hole in the fuel section that supplies fuel is generated. Since the numbers are set to be equal, the fuel section itself acts as a resonant muffler, and as a result, fluctuations in the fuel, that is, the excitation force of the flame, are extremely suppressed.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 and 2. In FIGS. 1 and 2, the same members as in FIG. 3 are given the same reference numerals. Further, 11 is a fuel supply chamber, 12 is a partition, 13 is a small hole, A is a combustion space, B is a burner, and C is a fuel part.

In FIG. 1, air supplied from a combustion fan 8 to an air chamber 2 and fuel supplied from a fuel nozzle 9 are connected to a burner consisting of a mixture chamber 6 and a flame lower, in which a part of the air and fuel are mixed. B causes combustion in the combustion chamber 2. After the combustion gas exchanges heat with water or air in the heat exchanger 3, it is transferred to the exhaust chamber 4.
is collected and exhausted from the exhaust pipe 5. At this time, the flame formed in the lower flame causes vibrations, and the volume of the combustion space A, which consists of the air chamber 1, burner B, combustion chamber 2, heat exchanger 3, exhaust chamber 4, etc., and the cross-sectional area of the exhaust stack. A noise having a peak at the first acoustic natural frequency r1 determined by the length of the exhaust stack is generated.

Here, acoustic specific tlie number f=c/2J S VTYC: Sound speed S2 Cross-sectional area of the exhaust stack l: Length of the exhaust stack ■: Represented by the volume of the combustion space.

Generally, in a combustion device, fl = 100 to 3007, and for this first acoustic natural frequency, the volume of the fuel supply chamber 11 and the disconnection of the fuel nozzle hole 9 in the fuel section that supplies fuel are Since the second acoustic natural frequency r2 determined by the area and the length of the fuel injection hole 9 is set to be equal, the fuel part itself acts as a resonant muffler and exhibits a remarkable noise reduction effect. . Furthermore, if it is difficult to set the second acoustic natural frequency r2 due to combustion, it can be easily set by providing a partition 12 with a small hole 13 inside the fuel supply chamber 11.

Effect of the invention As described above, the present invention has the following effects.

(1) Since the fuel section itself is a resonance type muffler, no additional space is required for the muffler, and the combustion device can be made smaller.

(2) Fluctuations in fuel flow rate result in pressure fluctuations, which become a source of noise. However, in the present invention, since the fuel section itself in which the fuel flow rate fluctuates also functions as a muffler, the muffling effect is significant.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a combustion device in an embodiment of the present invention;
FIG. 2 is a sectional view of the fuel section of the same device, and FIG. 3 is a sectional view of a conventional combustion device. 1... Air chamber, 2... Combustion chamber, 3...
... Heat exchanger, 4 ... Exhaust chamber, 5 ...
...Exhaust pipe, 6...Mixture chamber, 7...
Flame port, 8... Combustion fan, 9... Fuel injection hole, 11... Fuel supply chamber, 12...
・Fuel supply chamber, 13...Small hole, A...
Combustion space, B...burner.

Claims (2)

[Claims] (1) A burner consisting of an air chamber to which air is supplied from a combustion fan, a mixture chamber that mixes the air and fuel to create a mixed gas, and a flame port from which the mixed gas is ejected, and the air chamber; A combustion space portion including the burner, a combustion chamber, a heat exchanger, and an exhaust chamber, and an exhaust pipe communicating with the exhaust chamber are provided, and a fuel injection hole and the fuel injection hole for injecting the fuel into the mixture chamber are provided. a fuel supply chamber in which a hole is attached; the fuel supply chamber has a first acoustic natural frequency determined by the volume of the combustion space, the cross-sectional area of the exhaust stack, and the length of the exhaust stack; A combustion device in which the volume of the fuel nozzle and the second acoustic natural frequency determined by the cross-sectional area of the fuel nozzle and the length of the fuel nozzle are equal. (2) The combustion device according to claim (1), wherein the interior of the fuel supply chamber is divided into a plurality of parts by partitions having small holes.