JPS59147913A - Heat exchanger - Google Patents

Abstract

PURPOSE:To reduce the inner diameter of a tubular combustion chamber to a smaller one, maintaining high combustion efficiency and low noise, by constituting a mixing pipe so that the extended center line of injected combustion flames runs along the longitudinal direction of a combustion chamber, as well as to form a combustion gas inlet port between the mixing pipe and the tip end of a draft pipe. CONSTITUTION:A mixing pipe 20 is constituted in such a manner that the extended center line B of injected combustion flames runs along the longitudinal direction of a combustion chamber 3, together with a gap W of specified width being formed between the mixing pipe 20 and the end of a draft pipe 10. Combustion gas is injected from the mixing pipe 20 to the downward direction that is the longitudinal direction of a combustion chamber 3. Part of the gas rising up along the inside of a combustion chamber 3 by its own floating force reaches a circulation flow inlet port 16, forcibly sucked into the mixing pipe 20 from the gap W, and is mixed with the mixed mist of kerosene particles and fresh air. On the other hand, the combustion gas flowing out of the opening 4a at the lower end of a combustion cylinder 4 flows into a combustion exhaust gas passage 23, and is exhausted to the outside, after sufficiently exchanging heat with water in a water chamber 2c, contacting with all the periphery of side walls 2a of a can body 2. By this method, the inner diameter of a can body can be reduced to a smaller one, keeping high combustion efficiency and low noise in a heat exchanger.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat exchange device comprising a combustion device configured to gasify and burn a mixture of air and fuel by circulating combustion gas to a mixing pipe provided in front of a spray nozzle. .

BACKGROUND ART Conventionally, combustion devices such as oil water heaters include a type called a gun-type burner. This involves igniting and burning a mixture of fresh air sent from a blower and atomized fuel pressurized by an electromagnetic pump or the like and sprayed from a spray nozzle using a high-pressure electric discharge or the like. However, with this conventional method, the amount of air in the mixed mist is large, resulting in yellow flame combustion, resulting in poor combustion efficiency, and the carbon particles generated by yellow flame combustion adhere to the heat transfer surface inside the casing, reducing heat exchange efficiency. In addition, there was a drawback that the combustion noise caused by the vibration of the flame was loud.

Recently, there has been a demand for high combustion efficiency, low noise, and clean exhaust gas from the viewpoint of energy conservation and the environment, and so-called rotary gasification burners or heater gasification systems that gasify fuel oil and combust it with blue flame have recently been introduced. Burners are being developed.

However, in the former case, at the time of ignition and extinguishment,
There was a drawback that gasification of fuel oil was insufficient and odor was generated. Furthermore, the latter method requires a long time to preheat the heater, which is inconvenient in use, and also has the drawback of requiring complicated control of the heater. Furthermore, both have complicated fuel oil gasification structures and require special skills for maintenance and inspection.

The applicant of the present application has filed a heat exchange device in Japanese Patent Application No. 57-83799 to solve the above-mentioned drawbacks. That is, the heat exchange device @29 is as shown in FIG.
A cylindrical combustion chamber 33 is formed inside the cone 32 , and a spray nozzle 34 is installed inside a blast pipe 35 provided facing the combustion chamber 33 . A mixing tube 30 having a flame stabilizing plate 31 therein forms a combustion gas inlet 36 between the mixing tube 30 and the blast tube 35, and a combustion flame extension center of the mixing tube 30. The combustion chamber is installed so that the line G and the longitudinal center line H of the combustion chamber are perpendicular to each other.

By the way, when it is necessary to reduce the inner diameter of the cylindrical combustion chamber 33 due to restrictions on the installation location of the heat exchanger @29, the mixing tube 3
It is necessary to set the distance to the inner circumferential wall surface 32a' opposite to the inner circumferential wall surface 328' to a predetermined distance that does not cause local heating to occur on the inner circumferential wall surface 328'. However, in the heat exchange device 29, the combustion flame extension center line G of the mixing tube and the longitudinal center line IH of the combustion chamber 33 are
are perpendicular to each other, so that from the mixing pipe 30 to the mixing pipe 30
Since the distance to the inner circumferential wall surface 32a' facing the inner circumferential wall surface 32a' is the shortest distance, there are restrictions on reducing the diameter of the cylindrical combustion chamber 33, and there are cases where such requirements cannot be met.

An object of the present invention is to provide a heat exchange device that can reduce the inner diameter of a cylindrical combustion chamber without causing local heating while maintaining high combustion efficiency, low noise, and clean exhaust gas.

Hereinafter, the present invention will be explained based on embodiments shown in the drawings.

2 and 3 show a heat exchange device 1 according to a first embodiment of the present invention. In the heat exchange device 1, a combustion tube 4 is disposed inside a cylindrical cone 2, and an annular combustion exhaust gas passage 23 is formed at the gate between the inner peripheral wall 2a of the cone 2 and the combustion tube 4. The combustion cylinder 4 has a lower end opening 4a formed therein, and a downwardly hanging cylinder part 6a of the top plate 6 attached to the upper end of the cone 2.
It is connected and fixed to the lower end flange portion 6b of. The cone 2 has a double pipe structure in which a water chamber 2C is formed between an annular inner circumferential wall 2a and an annular outer circumferential wall 2b having an appropriate cross-sectional shape such as a circular cross-section or a polygonal cross-section. The outer periphery of the cone 2 is covered with a heat insulating material 5. Note that the cone 2 is not limited to the double pipe structure, and although not shown, it is of course possible to have a structure formed by winding a long small diameter pipe in a spiral shape. Near the upper end of the combustion chamber 3 formed inside the combustion tube 4, there is a hanging tube portion 6a of the top plate 6.
The tip of the blast pipe 10 inserted therein is positioned so as to face the inside of the combustion chamber 3 through the upper end opening 4b of the combustion chamber 3. The flange 10a of the air pipe 10 is connected and fixed to the top plate 6. A spray nozzle 8 is installed inside the blast pipe 10 . A mixing pipe 20 having a built-in flame stabilizing plate 17 is installed in the combustion chamber 3 and in front of the blast pipe 10 . The mixing pipe 20 has a predetermined gap W (for example, 15
mlll), and the extension center line B of the combustion flame ejected through the mixing tube 20 is oriented in the longitudinal direction of the combustion chamber 3.

In the illustrated embodiment, the mixing pipe 20 is installed so that the combustion flame extension center line B and the longitudinal center line A of the combustion chamber 3 are aligned with each other, but the illustration is not limited to this in any way. However, the combustion flame extension center line B may be inclined with respect to the longitudinal center line A by an appropriate inclination angle (for example, 30 degrees), and the combustion flame extension center line B may be inclined with respect to the longitudinal center line A. Appropriate eccentricity (for example, 1/3 to 1 of the radius of the combustion chamber 3)
Of course, it is also possible to make the combustion chamber 3 eccentric by /2) toward the outside of the combustion chamber 3. This gap W allows the mixing pipe 20 and the blower pipe 1 to
0, a circulating gas inlet (hereinafter referred to as a circulating inlet) 16 is formed near the top plate portion 4C of the combustion tube 4. Flame stabilizing section 1 having a multi-tube structure having the mixing tube 20
5, as shown in FIG. 3, a flame stabilizing plate 17 made of stainless steel punching metal or the like is installed near the center, and a tapered cone-shaped flame stabilizing tube 19 that expands in the downstream direction is provided on the outer periphery of the flame stabilizing plate 17. is installed. And this flame-holding cylinder 1
A sub-image flame tube 19 made of punched metal made of stainless steel or the like is installed on the outer periphery of 8, and a mixing tube 20 is further installed on the outer periphery of this. The flame holding plate 17. Flame-holding cylinder 18.
The sub-flame stabilizing tube 19 and the mixing tube 20 are supported by support legs 21, 21...
・The mixing pipe 20 is connected to the blower pipe 1.
It is suspended on 0 with legs 22°22... Note that the flame stabilizing tube 18 and the sub-image flame tube 19 are installed as necessary, and are not necessarily required. A spray nozzle 8 is installed at the rear of the flame holding section 15 so as to be substantially aligned with the combustion flame extension center line B, and sprays fuel oil pressurized by a hydraulic pump 7 (see FIG. 5, which will be described later). It is configured to eject as fine particles in the form of mist. At the outer periphery of the spray nozzle 8, a blowing pipe 10 is installed which blows fresh air blown in a blowing mode 9 (see FIG. 2) to the mixing pipe 20. A high-speed air jetting plate 11 is installed at the tip opening of the blast pipe 10, if necessary. The ejection plate 11 has a central ejection hole 12 for ejecting atomized fuel and fresh air, and a plurality of air ejection holes 13 formed at appropriate circumferential pitches at a predetermined distance from the center. Each of the air jet holes 13 is inclined at a predetermined angle in the circumferential direction.
A swirling flow is generated in the ejected air to further refine the fuel particles and to evenly distribute the mixture of atomized fuel and fresh air. Reference numeral 14 denotes an electrode rod that generates a spark using high-voltage electricity near the tip of the spray nozzle 8 and ignites the fine particles of fuel oil that are ejected. In FIG. 2, 25 is a combustion tube, 24 is an exhaust chimney, and 27 is a hot water supply port.

Next, the operation of the heat exchange device 1 configured as described above will be explained as follows.
The explanation will be based on the case where water is used as the heat exchange fluid, kerosene is used as the fuel oil, and the amount of kerosene and fresh air supplied are constant.

The atomized kerosene particles ejected from the spray nozzle 8 are ignited by the spark of the electrode rod 16, and at first begin yellow flame combustion near the tip of the ejection plate 11.

In this condition there is an excess of air. After that, this combustion flame gradually moves toward the spray direction and is propagated to the secondary flame cylinder 19,
Further, it moves to the flame stabilizing plate 17, is rectified on the way to the flame stabilizing plate 17, becomes stable on the flame stabilizing plate 17, and is guided to the flame stabilizing tube 18 to maintain steady combustion. In this way, the sub-image flame cylinder 19
serves to smooth the propagation of the combustion flame when it moves to the flame holding plate 17. Note that the ejection plate 11. When the flame stabilizing tube 18 and the subimage flame tube 19 are not installed, stable combustion is started and maintained at the holding roots 17 by spark ignition near the flame stabilizing plate 17.

As shown in FIG. 2, part of the combustion gas (not shown) ejected from the mixing pipe 20 downward in the longitudinal direction of the combustion chamber 3 rises within the combustion chamber 3 due to its own buoyancy and flows into a circulating flow. It reaches entrance 16. The combustion gas flows from the periphery of the circulation inlet 16 into the mixing pipe 20 in a substantially uniform state due to the negative pressure generated by the swirling air flow passing through the gap W from the blast pipe 10 to the mixing pipe 20- at high speed. It is forcibly drawn into the air and instantly mixed into a mixed mist of kerosene particles and fresh air. On the other hand, the combustion gas coming out of the lower end opening 4a of the combustion tube 4 flows into the combustion exhaust gas passage 23, and while passing through the combustion exhaust gas passage 23, it comes into contact with the entire circumference of the inner circumferential wall 2a of the mounting body 2 and forms an ice chamber. After sufficiently exchanging heat with the water in 2C, it is discharged to the outside via the exhaust chimney 24. The circulating combustion gas sucked into the mixing tube 20 warms the mixed mist of very fine kerosene particles and fresh air due to the swirling air flow, and instantly turns the kerosene particles into a gaseous state or a state close to this. . Therefore, the combustion state becomes gasification combustion or a state close to this, and blue flame combustion from the flame stabilizing plate 17 is obtained. In other words, kerosene particles, fresh air, and circulating combustion gas are mixed in the mixing tube 20 and then rectified, and what used to be combustion with excess air becomes an ideal combustion that is close to the stoichiometric air ratio and is rectified. Become. Therefore, combustion with low combustion noise and excellent heat exchange efficiency can be obtained. From then on, this blue flame combustion is maintained.

In order to obtain the gastritis combustion described above, it is necessary to mix an appropriate amount of combustion gas into the mixed mist of fresh air and kerosene particles, and to reduce the negative pressure (suction effect) generated at the circulation inlet 16. The size of is a problem. Therefore, in this example, as a result of conducting experiments by changing the flow velocity of the ejected air, which has the greatest effect on the negative pressure, we were able to set a flow velocity sufficient to suck in the amount of combustion gas required for the ideal air ratio. Ta. Factors that affect the flow velocity of the ejected air are the hole diameters of the central ejection hole 12 and the air ejection hole 13 and the diameters of the air ejection holes 13 and both ejection holes 12, assuming that the output of the blower 9 and the inner diameter of the air pipe 10 (in this case, the diameter is 80 mm) are constant.
The area ratio is 13. Note that the number of air ejection holes 13 and the distance between the central ejection hole 12 and the air ejection hole 13 have little effect on the flow velocity of the ejected air and can be ignored. However, if the distance between the two nozzle holes 12 and 13 exceeds an optimum value, good mixing of kerosene particles and air will not be obtained. This example in which the diameter of the blower pipe 10 is 80 mm (
When the combustion output was 35,0OOK cal/Hr), the distance between the central nozzle 12 and the air nozzle 13 was appropriately 32 mm.

Tables 1 and 2 are experimental results showing the relationship between the hole diameter of the nozzle 12.13 and the air flow rate and amount of supplied air when ejected from the nozzle 12.13 into the natural atmosphere.

Table 1 As can be clearly seen from Table 1, if the diameter of the air jet hole 13 is made smaller, the flow velocity of the jet air becomes faster, and the circulation inlet 1
6, the negative pressure generated becomes larger. However, the amount of supplied air tends to decrease as the diameter of the air jet hole 13 becomes smaller. Therefore, a hole diameter of 8111 m is required to ensure a sufficient amount of supplied air and a high flow rate.

Table 2 However, the aperture ratio of the holes 12 is the value obtained by dividing the opening area of the central nozzle 12 by the sum of the opening areas of the central nozzle 12 and the air nozzle 13, multiplied by 100.

Further, as is clear from Table 2, if the hole diameter of the central jet hole 12 is made smaller, the flow velocity becomes faster, but the amount of supplied air decreases. Moreover, the central nozzle 12 and the air nozzle 13
The ratio of the opening area of the central jet hole 12 to the entire opening area of the central jet hole 12 takes a value proportional to the amount of air. Therefore, the diameter of the central jet hole 12 is optimally 18 to 20 mm, regardless of the balance between the amount of air supplied and the flow rate of the jet air.

The diameter of the central nozzle 12 is 18 mm, the diameter of the air nozzle 13 is 8 mff1, and the diameter of the air nozzle 13 is 8+nm.
Assuming that the diameter of the blast pipe 10 was 80 mm, the actual air flow velocity was measured to be 21 m 2 /sec. For reference, the air flow rate of commercially available combustion devices is usually 1
It was about 2.5m/SeC.

In short, the flame stabilizing section 15 warms the kerosene particles in the mixing tube 20 with circulating combustion gas to turn them into a gasified state or a state close to this, and also adds combustion gas to the mixed mist of air and kerosene particles. Since gastritis combustion is performed at an air ratio close to the air ratio, a large amount of heat is generated for a given amount of fuel, resulting in excellent thermal efficiency. Furthermore, since it is a rectified blue flame combustion, it also has the advantage of low combustion noise.

FIG. 4 shows a second embodiment of the present invention,
The difference from the first embodiment (see FIG. 2) is that the lower end 7 of the top plate 6 has a flange portion 6b and the partition wall 4C serving as the top plate of the combustion tube 4.
A gap W is provided between the two to form the circulation inlet 16, and the two are connected and fixed by connecting rods 28, 28, . . . . Combustion gas (not shown) ejected downward in the longitudinal direction of the combustion chamber 3 from the mixing pipe 20 flows into the combustion exhaust gas path 23 from the lower end opening 4a of the combustion tube 4, and while passing through the combustion exhaust gas path 23. After sufficiently exchanging heat with the water in the ice chamber 2C while contacting the entire circumference of the inner peripheral wall 2a of the string 2, it reaches the outer upper end of the combustion tube 4, and a part of it reaches the circulation inlet 16. . A part of the combustion gas flows from around the circulation inlet 16 into the mixing pipe 20 in a substantially uniform state due to the negative pressure generated by the swirling air flow passing from the blast pipe 10 to the mixing pipe 20 at high speed. The kerosene particles are forcibly sucked in, instantly turning them into gas or a state close to this. For this reason,
The combustion state is gasification combustion or a state close to this, and blue flame combustion from the flame stabilizing plate 17 is obtained. The mixing tube 2
The remaining gas other than the combustion gas that has been circulated to zero is exhausted to the outside via the exhaust chimney 24.

FIG. 5 shows a third embodiment of the present invention,
The difference from the first embodiment (see FIG. 2) is that the cylindrical combustion chamber 3 is formed from the inner circumferential wall 2a of the cone 2, and is formed closer to the center of the bottom plate 29 of the combustion chamber 3. Opening 2
The tip of the blower pipe 10 inserted into the combustion chamber 9a is positioned so as to face upward in the combustion chamber 3, and a combustion tube 25 is built in above the combustion chamber 3 to form a combustion exhaust gas path 23. It is a point. In addition, 26 in the figure is a water supply pipe.

A part of the combustion gas (not shown) ejected from the mixing pipe 20 upward in the longitudinal direction of the combustion chamber 3 collides with the bottom surface of the combustion tube 25 and changes direction, and then reaches the inner circumferential wall 2a of the string 2. It flows downward while exchanging heat along the entire circumference and reaches the circulation inlet 16. Then, the combustion gas is forcibly drawn into the mixing tube 20 in the same manner as described above, and the kerosene particles are instantaneously turned into gas or a state close to this. Therefore, the combustion state becomes gasification combustion or a state close to this, and blue flame combustion from the flame stabilizing plate 17 is obtained. The remaining gas, excluding the combustion gas that has circulated to the mixing pipe 20, contacts the entire circumference of the inner circumferential wall 2a of the string 2 while passing through the combustion exhaust gas passage 23, and heats up the water in the water chamber 2C. After being replaced, it is exhausted to the outside via the exhaust chimney 24.

FIG. 6 shows a fourth embodiment of the present invention,
The difference from the third embodiment (see FIG. 5) is that the annular ceiling surface 3a of the cylindrical combustion chamber 3 is formed from the inner circumferential wall 2a' of the string 2, and The combustion exhaust gas path 23 extending upward is formed by the inner circumferential wall 2a' of the string body 2. A part of the combustion gas (not shown) ejected from the mixing pipe 20 upward in the longitudinal direction of the combustion chamber 3
After colliding with the annular ceiling surface 3a and changing direction, it flows downward while exchanging heat along the entire circumference of the inner circumferential wall 2a of the string 2 and reaches the circulation inlet 16. Then, the combustion gas is forcibly drawn into the mixing tube 20 in the same manner as described above, and the kerosene particles are instantaneously gasified or in a state close to this, and blue flame combustion from the flame stabilizing plate 17 is obtained.

Although the heat exchange device 1 shown in FIGS. 4, 5, and 6 is installed vertically as shown, it is not limited to being vertically installed, and although not shown, the combustion Of course, it is also possible to install it horizontally so that the longitudinal centerline of the chamber 3 is horizontal.

As explained above, the heat exchange device according to the present invention has the following excellent effects.

■ Since the extension center line of the combustion flame ejected from the mixing tube is oriented in the longitudinal direction of the cylindrical combustion chamber,
Since there is no need to locally heat the inner circumferential wall of the string,
Compared to a conventional heat exchange device in which the combustion flame extension center line of the mixing tube and the longitudinal center line of the combustion chamber are perpendicular to each other, the inner diameter of the string can be made smaller, making it possible to meet the demand for smaller diameters.

■ By circulating the combustion gas through the mixing tube and warming the fuel particles, they are brought to a state close to gasification, and at the same time, by adding combustion gas to the mixture of fresh air and fuel particles, the air ratio is close to the stoichiometric air ratio. By burning it, blue flame combustion can be achieved, a large amount of heat is generated for a given amount of fuel, and the device has excellent thermal efficiency.

■ It has the advantage of low combustion noise due to the constant gastritis combustion flame and the rectifying effect of the mixing tube.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional heat exchanger, and Figures 2 to 6 are
The figures all show embodiments of the heat exchange device according to the present invention, and FIG. 2 is a longitudinal sectional view of the heat exchange device showing the first embodiment, and FIG. 3 is a mixing pipe, a blower pipe, etc. FIG. 4 is a vertical cross-sectional view of the heat exchange device without showing the second embodiment, FIG. 5 is a vertical cross-sectional view of the heat exchange device without showing the third embodiment, and FIG. The figure is a longitudinal cross-sectional view of the heat exchange device, not showing the fourth embodiment. 2... Cone 3... Combustion chamber 4c... Partition wall 8... Spray nozzle 10... Air pipe 16... Circulation inlet (combustion gas inlet) 17... Flame holding plate 20...Mixing pipe 23...Combustion exhaust gas path B...
Combustion flame extension center line patent applicant: Representative of Ina Seito Co., Ltd. Patent attorney: Toshihiko Uchida Figure 1

Claims (1)

[Scope of Claims] 1. A cylindrical combustion chamber is formed inside the continuous body, and a tip of a blow pipe is positioned near one end of the combustion chamber so as to face inside the combustion chamber, and the inside of the blow pipe is A spray nozzle is installed in the combustion chamber, and a mixing tube with a built-in flame-holding plate is installed in the combustion chamber and at a position in front of the blast tube, and the mixing tube has a combustion gas inlet between it and the tip of the blast tube. A heat exchange device characterized in that an extended center line of a combustion flame formed and ejected through the mixing tube is oriented in the longitudinal direction of the combustion chamber. 2. The heat exchanger according to claim 1, wherein the combustion gas inlet is formed within the combustion chamber. 3. A combustion exhaust gas passage is formed outside a partition wall forming one end of the combustion chamber, and the combustion gas inlet is formed within the combustion exhaust gas passage. The heat exchange device according to scope 1.