JPH04129626U - Combustion device exhaust pipe and water heater or bathtub with hot water supply equipped with the exhaust pipe - Google Patents

Abstract

(57) [Summary] [Purpose] To reliably prevent combustion vibration with a simple structure. [Configuration] Burner, burner chamber that stores it, blower,
A part of the exhaust chamber 7 side of the exhaust tube 8 of the combustion device composed of a combustion chamber, a heat exchanger, an exhaust chamber, and an exhaust tube 8 is made into a double tube 19 consisting of an inner tube 20 and an outer tube 21. A plurality of small holes 22 are provided in the inner cylinder 20, and a space 23 is formed by the outer cylinder 21 provided around the inner cylinder 20 to form a Helmholtz-type resonator, which absorbs the energy of the generated pressure fluctuation. , prevent the occurrence of combustion vibration.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention particularly includes an exhaust stack and its exhaust stack that prevent combustion vibrations of the combustion device. Regarding water heaters or bathtubs with hot water supply.

0002

[Conventional technology]

FIG. 5 shows the configuration of a conventional combustion device. FIG. 6 shows its side view.

0003 This combustion device has a plurality of burners 1, and the burners 1 are placed at the same position in the height direction. A burner chamber 3 for housing at the same pitch in the width direction, a blower 4, and a combustion chamber 5. , a heat exchanger 6, an exhaust chamber 7, and a cylindrical exhaust pipe 8. fuel gas 10 is injected into the inside of the burner 1 from the nozzle 9 corresponding to each burner 1, and is used for combustion. Air is supplied from a blower 4. A part of the combustion air is used as primary air 11 for combustion. After flowing into the burner 1 together with the raw material gas 10 and mixing inside the burner 1, The premixed gas 13 is ejected from the flame port 2 of the burner 1, forming a primary flame 14. do.

0004 Furthermore, a secondary flame 15 is formed by secondary air 12 supplied from around the burner 1. complete combustion. The high temperature combustion gas 16 generated by combustion is transferred to a heat exchanger 6. The heated fluid 18 is then heated. The combustion gas 16 whose temperature has decreased is exhausted. The gas becomes gas 17, passes through the exhaust chamber 7 and the exhaust pipe 8, and is discharged to the outside.

[0005]

[Problem that the idea aims to solve]

In such combustion devices, the bar is generally adjusted to the acoustic natural frequency of the combustion device. Combustion oscillation occurs in which combustion at No. 1 causes positive feedback and resonates. Cheap. This is due to sudden temperature changes caused by combustion in the combustion chamber 5, resulting in pressure fluctuations. occurs, and this pressure fluctuation causes the secondary air 12 flowing around the burner 1 and the Premixed gas 13 is ejected from the flame port 2 and ejected from the nozzle 9 on the upstream side thereof. This causes fluctuations in the fuel gas 10 and primary air 11, and these fluctuations cause It is said that the heat generation rate of the flame formed in Na 1 fluctuates, further amplifying pressure fluctuations. This is because of the phenomenon.

[0006] When combustion vibrations occur, the noise emitted from the combustion equipment increases, and as shown in Figure 7. The combustion oscillation frequencies shown in the diagram form a prominent spectrum. this is very unpleasant In addition to giving a sensation of This is a serious problem that can lead to severe vibrations and even damage to the combustion equipment. Conventionally, this If combustion vibration occurs, change the amount of fuel gas and combustion air to adjust the operating conditions. For those who want to change the specifications of burner 1's flame port 2 through trial and error. There is no established method to reliably prevent combustion vibration using a simple method. won.

[0007] This invention is a combustion equipment exhaust system that can reliably prevent combustion vibration with a simple structure. The purpose is to provide a water heater or a bathtub with hot water supply equipped with a cylinder and its exhaust pipe. That is.

[0008]

[Means to solve the problem]

To achieve this purpose, the present invention includes a burner and a burner chamber that houses the burner. , in a combustion device consisting of a blower, combustion chamber, heat exchanger, exhaust chamber and exhaust stack. At least a part of the exhaust pipe on the exhaust chamber side is made into a double pipe consisting of an inner pipe and an outer pipe, and the inner pipe In addition to having multiple small holes, a space is formed with an outer cylinder around the inner cylinder. It is something. Furthermore, the exhaust pipe of the above-mentioned combustion device is installed in the water heater or bathtub with hot water supply. It is something that can be achieved.

[0009]

[Effect]

In this invention, a part of the exhaust stack is made into a double pipe to form a Helmholtz-shaped resonator, It can absorb the energy of pressure fluctuations that occur and prevent combustion vibrations. Ru. As a result, the spectrum of noise emitted by the combustion equipment is flattened, and The overall level is also low, so noise does not cause discomfort. Additionally, this configuration burns It is possible to obtain the effect by adopting it from the design stage of the equipment, and it is also possible to It is also a very simple and reliable countermeasure in the event of an accident.

0010

【Example】

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. Here the combustion equipment The basic configuration is the same as that shown in FIGS. 5 and 6 in the conventional technology, and the detailed explanation thereof is as follows. is omitted. The structure of the exhaust pipe 8 will be explained below. This exhaust pipe 8 is the outlet of the exhaust chamber 7. A part of the exhaust pipe 8 on the exhaust chamber 7 side is formed into a double pipe 19 consisting of an inner pipe 20 and an outer pipe 21. It consists of A plurality of small holes 22 are provided in the inner cylinder 20, and a plurality of small holes 22 are provided around the inner cylinder 20. A space 23 is formed by the outer cylinder 21.

[0011] In FIG. 1, part of the exhaust pipe 8 is made into a double pipe 19, but the entire exhaust pipe 8 is made into a double pipe 19. Alternatively, as shown in FIG. The inner cylinder 20 may be divided into sections, and a small hole 22 may be provided in each inner cylinder 20. In addition, as shown in Figure 3, multiple The double cylinders 19 may be arranged intermittently.

0012 Next, the functions of the above configuration will be explained. Part or all of the exhaust pipe 8 is an inner pipe. 20 and an outer cylinder 21. The inner cylinder 20 has a plurality of small holes 2. 2, the inner cylinder 20 and the outer cylinder 21 form a space 23, and this double cylinder 19 serves as the helm home. It will act as a Ruth-shaped resonator. In other words, the small hole 22 of the inner cylinder 20 is directly connected. The resonant frequency of the Helmholtz resonator determined by the diameter, number, and size of the space 23 is If it matches the frequency of pressure fluctuation, it will absorb the energy of this pressure fluctuation. As a result, pressure fluctuations are attenuated and combustion oscillations do not occur.

[0013] For example, if the acoustic natural frequency of the combustion device is 90Hz, the inner cylinder 20 The diameter is Φ80mm, the thickness of the inner cylinder is 0.6mm, and the diameter of the outer cylinder 21 is Φ150mm. , the length of the outer cylinder is 400 mm, the diameter of the small hole 22 of the inner cylinder 20 is 2 mm, and the number of pieces is 6. Therefore, the Helmholtz resonance frequency of this part is also about 90Hz, which is the combustion vibration. It is possible to absorb the energy of pressure fluctuations with this resonator. Also, in general, In the combustion apparatus shown in FIGS. 6 and 7, exhaust air is emitted from the blower 4 or the burner chamber 3. Pressure fluctuations with the same phase tend to occur up to chamber 7, and this is the basic mode of combustion oscillation. Therefore, a Helmholtz-shaped resonator is installed in the exhaust stack 8 to absorb it. That is, it is desirable that the double cylinder 19 be as close to the exhaust chamber 7 as possible. Here, burn The spectrum of noise emitted from the baking equipment is flat as shown in Figure 4, and The overall level is also low, so noise does not cause discomfort. Furthermore, the present invention It is possible to obtain the effect by adopting it from the design stage of the equipment, and it is also possible to It is also a very simple and reliable countermeasure in the event of an accident.

[0014] Furthermore, a water heater and a bathtub with hot water supply provided with the exhaust pipe 8 configured as described above. Explain. The basic configuration of the water heater is the same as the conventional combustion device shown in Figures 5 and 6. These are surrounded by an exterior. In addition, the bathtub with hot water supply is shown in Figures 5 and 6. It has a configuration in which two conventional combustion devices are placed side by side, and they are surrounded by the same exterior. be. The fluid to be heated in both the water heater and the bathtub with hot water supply is water.

[0015]

[Effect of the idea]

According to this invention, a part of the exhaust stack forms a Helmholtz-shaped resonator with a double pipe. Since it absorbs the energy of pressure fluctuations that occur, it can prevent combustion vibrations from occurring. I can do that. As a result, the spectrum of noise emitted by the combustion equipment is flattened. Also, since the overall level is low, it has the advantage of not causing discomfort due to noise. Ru. Furthermore, it can be adopted from the design stage of combustion equipment, and This is a very simple and reliable measure to take when a movement occurs.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing the structure of an embodiment of an exhaust stack of a combustion device of the present invention.

FIG. 2 is a sectional view showing the structure of another embodiment of the exhaust stack of the combustion device.

FIG. 3 is a configuration diagram showing the structure of another embodiment of the exhaust stack of the combustion device.

FIG. 4 is a characteristic diagram showing a noise spectrum and used to explain the functions of the embodiment.

FIG. 5 is a front view showing the structure of a combustion device provided with a conventional exhaust stack.

FIG. 6 is a side and partial cross-sectional view of the combustion device in FIG. 5;

FIG. 7 is a characteristic diagram showing a noise spectrum when combustion vibration occurs using a conventional exhaust stack.

[Explanation of symbols] 1 burner 2 Flame opening part 3 Burner room 4 Air blower 5 Combustion chamber 6 Heat exchanger 7 Exhaust chamber 8 Exhaust stack 9 Nozzle 10 Fuel gas 11 Primary air 12 Secondary air 13 Premixed gas 14 Primary flame 15 Secondary flame 16 Combustion gas 17 Exhaust gas 18 Fluid to be heated 19 Double tube 20 Inner cylinder 21 Outer cylinder 22 Small hole 23 Space 24 Partition plate

──────────────────────────────────────────────── ─── Continuation of front page (72) Creator Koji Tajima Hitachi Chemical, 1500 Oaza Ogawa, Shimodate City, Ibaraki Prefecture Inside the Shimodate Research Institute of Kogyo Co., Ltd.

Claims (2)

[Scope of utility model registration request] Claim 1: A combustion device comprising a burner, a burner chamber housing the burner, a blower, a combustion chamber, a heat exchanger, an exhaust chamber, and an exhaust stack, wherein at least a part of the exhaust stack on the exhaust chamber side is An exhaust pipe for a combustion device, characterized in that it has a double cylinder consisting of an inner cylinder and an outer cylinder, the inner cylinder is provided with a plurality of small holes, and a space is formed by the outer cylinder provided around the inner cylinder. 2. A water heater or a bathtub with hot water supply comprising the exhaust stack of the combustion device according to claim 1.