JPH0327813B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has a heat exchanger in which a heat exchanger tube is provided with fins, and the side of the fin facing the burner has an uneven shape according to the outer diameter of the heat exchanger tube. The present invention relates to a forced air combustion device exhibiting the following characteristics.

[Prior Art] In a forced air combustion device, for example, an instantaneous water heater, a heat exchanger is installed in which multi-layered fins are attached to a heat transfer tube. This heat exchanger is located opposite the burner, and is heated by the flame formed on the burner, and the heat is transmitted from the outer peripheral edge of the fin to the water supply pipe as a heat transfer tube, turning the water inside into hot water.

At this time, the heat exchanger tubes of the heat exchanger are approximately parallel to the burner, and the outer peripheral edge of the fins on the side facing the burner has an uneven heat transfer part, for example a wave-shaped uniform heat transfer part, in accordance with the outer diameter of the heat exchanger tube. The fins are formed so that the distance dimension in the direction from the outer peripheral edge of the fin to the heat exchanger tube is approximately uniform,
This is to avoid deformation due to expansion.

[Problems to be Solved by the Invention] In recent years, it has been considered to shorten the distance between the heat exchanger and the burner in order to reduce the overall size while performing high-load combustion. In this case, if this distance is shortened too much, the flame from the burner will come into contact with the convex parts of the fins, producing harmful gases such as carbon monoxide and reducing combustibility. However, if the height of the flame is shortened in order to avoid contact of the flame with the fins, there are mutually contradictory problems such as the flame intensity decreases and high-load combustion is impaired.

[Purpose of the Invention] This invention was made in an attempt to eliminate the above-mentioned contradictory problems.The purpose of this invention is to achieve high-load combustion, reduce the overall size, and reduce the generation of harmful gases such as carbon monoxide. To provide a forced air combustion type combustion device which exhibits excellent effects such as preventing combustion from occurring and ensuring good combustibility.

[Means for solving the problem] In order to achieve the above object, a large number of nozzle holes are provided uniformly with the same diameter and are arranged horizontally, so that flames are generated by ignition of the supplied fuel gas. A plate-shaped burner that forms a heat exchanger disposed in parallel above the burner and heated by the flame from the burner; and a heat exchanger disposed below the burner in parallel with the burner. In a forced air combustion device comprising a baffle plate having a group of holes, the opening of the through hole of the baffle plate is made smaller in the convex part of the uniform heat transfer part of the heat transfer fin, and The configuration is large and has been set.

[Operation and Effects of the Invention] According to the present invention, even though the heat transfer fins of the heat exchanger form uneven heat transfer portions, the convex portions of the heat transfer portions of the heat transfer fins The opening of the through holes in the rectifying plate is set small for the convex part, and large for the concave part, so even the heat transfer fins in the convex part do not come into contact with the flame, so the heat exchanger The distance between the burner and the burner can be shortened, resulting in good combustion performance and a more compact overall design.
It is possible to provide an excellent forced air combustion device that enables high-load combustion.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. 1 to 3 show an instantaneous gas water heater to which the forced air combustion device of the present invention is applied.

In this example, a forced air combustion device was applied to the instantaneous gas water heater 1. The instantaneous gas water heater 1 is housed in a main body case 10, and includes a combustion section 2, a heat exchange section 3, a centrifugal blower 7 which is a supply section that supplies combustion air to the combustion section 2, and a gas supply path. 8 and an electronic control device 9. The main body case 10 has an opening 11 that takes in combustion air and an opening 12 that exhausts combustion exhaust.

The combustion section 2 includes a combustion case 20 provided with an exhaust section 4 on the upper part, and a fixing fitting 21 on the combustion case 20.
It consists of a combustion chamber 23 equipped with a burner plate 22 made of ceramic and having a large number of injection holes V formed in a ceramic plate, and a mixing chamber 24 provided at the lower part of the combustion chamber 23.

The heat exchanger 3 is composed of a group of plate fins 31 arranged in high density, a water supply pipe 32 as a heat transfer tube, and a hot water supply pipe 33. Exchanges heat with combustion exhaust.

In this case, the water supply pipe 32 has a circular cross section and is disposed above the burner plate 22 in a parallel manner, and the plate fin group 31 is disposed around the outer periphery of the water supply pipe 32 so as to intersect with each other in the longitudinal direction. The outer peripheral edge side of the plate fin group 31 facing the upper surface of the burner plate 22 is formed into an uneven shape, that is, a wave surface shape, and the wave surface portion is a uniform heat transfer portion 31a. The wavy portion of the equal heat transfer portion 31a is located concentrically with the water supply pipe 32, so that the distance from the equal heat transfer portion 31a to the water supply pipe 32 is substantially uniform regardless of the location.

Now, reference numeral 100 denotes a rectifier plate as a fire force adjustment means, which is disposed below the burner plate 22 as shown in FIG. 2 in detail.
2 and the upper end opening 24a of the mixing chamber 24. This current plate 100 is formed with fine through holes 100a having the same diameter.
Of the through-holes 100a, the portions H facing the peaks M of the uniform heat transfer portion 31a in the plate fin group 31 are set in a rough state with a low arrangement density, and the portions K facing the valleys V are set in a rough state with a low arrangement density. It is set to a dense state.

On the other hand, as shown in FIGS. 5 to 7, the exhaust section 4 is an exhaust pan which forms an exhaust passage 41 inside thereof, which has an inlet section 41a, a bent section 41b, and a rectangular exhaust port 41c opening toward the outside. 42 and an exhaust hood 6. As shown in FIG. 5, the exhaust pan 42 is attached to the upper part of the combustion case 20, has a rectangular hole 43a, and has a sound-absorbing material 43c surrounded by a diamond-shaped wire mesh (rathmetal) 43b for protection. is provided in the lower part 42a. Further, the exhaust pan 42 includes holding frames 44 to 46 that hold sound absorbing materials 43d and 43e arranged to reduce the opening area of the exhaust port 41c of the exhaust passage 41 opened on the side surface.
It has a ceiling plate 47 that holds a sound absorbing material 43f provided on the upper part 42b, and an upper plate 48.

Further, the holding frame 44 includes an opening 44a provided to form an exhaust port 41c of the exhaust passage 41;
An inner circumferential edge 44b provided on the inner circumference of the opening 44a.
It extends from the lower edge 44c of the inner circumferential edge 44b in a direction that reduces the opening area of the exhaust port 41c of the exhaust passage 41. Furthermore, holding frames 45, 4
6 and the ceiling plate 47, a large number of circular through holes connect the sound absorbing materials 43d, 43e, and 43f to the exhaust passage 4.
It is perforated so that it is exposed to 1.

Exhaust hood 6 shown in detail in FIGS. 6 and 7
, which covers the exhaust port 41c of the exhaust passage 41, is attached to sandwich the outer peripheral edge 44h of the holding frame 44, and has slit-shaped exhaust ports 65a, 65b and similar exhaust ports 65c, on both left and right sides. 6
5d are formed in two upper and lower stages. Note that 67 is a mounting hole, and the exhaust hood 6 is connected through this hole 67.
is fastened to the holding frame 44 with screws or the like.

On the other hand, the centrifugal blower 7 includes a scroll casing 71, a fan 72, and a driving motor 73 for the fan 72. scroll casing 7
1 is a cylindrical body 75 that has a spiral shape and is fastened to a side surface 74; and a shielding plate 76 that is fastened to the cylindrical body 75.
and a dustproof net 77 that covers the shielding plate 76.

The cylindrical body 75 forms a bell-mouth-shaped suction port 78 that is open to the outside, and a tip 79 fits into the fan 72 by a predetermined distance that takes into account the rotational speed of the centrifugal blower 7.

As shown in FIG. 8, the shielding plate 76 includes a conical portion 76b having a tip 76a located at the center of a bellmouth-shaped suction port 78, and a circle extending outward from the other end 76c of the conical portion 76b. A plate portion 76d and three L-shaped mounting legs 76 hanging from the disk portion 76d.
e, and three L-shaped dustproof net attachment parts 76f protruding from the disc part 76d. The L-shaped dustproof net mounting part 76 has three L-shaped mounting legs 76e.
Since the shielding plate 76 extends toward the outer circumference from f,
The dustproof net 77 can be attached to the cylindrical body 75 after being assembled in advance.

The gas supply path 8 is integrally molded with the scroll casing 71 and includes a gas jet nozzle 81 that discharges fuel gas, a gas supply pipe 82 that supplies fuel gas to the gas jet nozzle 81, and a gas control unit 83. Become. Gas control unit 8
3 is an electromagnetic on-off valve 84 that is provided between the gas jet nozzle 81 and the gas supply pipe 82 and opens and closes when energized or de-energized, and an electromagnetic on-off valve 84 that is provided downstream of the on-off valve 84 to adjust the gas flow rate. It is provided with a governor valve (not shown) and an electromagnetic proportional control valve 85 which is provided downstream of the governor valve and whose opening ratio is varied according to the amount of current supplied. An orifice 86 for adjusting the supply pressure and flow rate of fuel gas is attached to the other end of the gas jet nozzle 81.

The electronic control device 9 includes a switch (not shown) that is activated when the instantaneous gas water heater 1 is used, and a temperature adjustment knob (not shown) that is operated by the user to set the temperature of water flowing out from the hot water pipe 33. (not shown), thermocouple 91 that detects the oxygen supply state of the flame of burner plate 22, burner plate 2 at the time of ignition
It controls the energization and de-energization of the spark electrode 92 that blows sparks on the combustion surface of the fuel cell 2, the drive motor 73 of the centrifugal blower 7, the gas control unit 83, and the like.

Next, the operation of the above configuration will be explained.

In the instantaneous gas water heater 1, when the switch is closed, the fan 72 of the centrifugal blower 7 rotates, and combustion air is supplied from the scroll casing 71 to the burner plate 22 through the through hole 100a of the rectifier plate 100. . Then, the electronic control device 9 controls the on-off valve 84 and the proportional control valve 85 of the gas control unit 83.
The on-off valve 84 and the proportional control valve 85 are opened. Furthermore, the combustion air existing outside the scroll casing 71 is sucked in after dust and dirt are removed by the dustproof net 77 and the flow rate of the combustion air is throttled by the cylindrical body 75.

Then, the spark electrode 92 is controlled by the electronic control device 9.
A spark discharge occurs at the burner plate 22 to ignite the fuel gas and start combustion. The combustion exhaust from the burner plate 22 passes through the heat exchanger 3 as an exhaust stream and reaches the inlet section 41a of the exhaust section 4.
In this process, the heat of the exhaust flow is transmitted from the uniform heat transfer portion 31a of the plate fin group 31 to the water supply pipe 32 and is applied to the water inside. This operation is repeated in sequence to exchange heat between the exhaust flow and the water in the water supply pipe 32, and hot water is supplied from the water supply pipe 33. Thereafter, the exhaust flow exits from the exhaust port 41c through the hole 43a of the sound absorbing material 43, and is then exhausted from the exhaust ports 65a, 65b, 65c, and 65d of the exhaust hood 6.

According to the above configuration, the through holes 100 of the current plate 100
Since the arrangement state of a is set to be coarse for the peaks M of the uniform heat transfer portion 31a in the plate fin group 31 and densely arranged for the valleys V, The amount of fuel gas passing from the opposing jet ports V decreases, and the amount of fuel gas passing from the jet ports V opposing the valley portion increases. As a result, as shown in FIG. 2, the force of the flame F on the burner plate 22 is small toward the peaks M, and becomes large toward the valleys. Accordingly, the height dimension of the flame F is adjusted to be large or small according to the valleys and peaks M, and there is As can be seen in FIG. 2, a substantially uniform distance results. As a result, the flame F and the fins 31 are brought into the heat exchanger 3 in a non-contact state.
The space between the burner plate 22 and the burner plate 22 can be shortened, and the entire structure can be made more compact without generating toxic gas. Moreover, a large amount of heat can be applied to enable high-load combustion.

Furthermore, since there is a substantially uniform distance between the tip of the flame F and the uniform heat transfer section 31a, the uniform heat transfer section 31a receives the heat of the flame F evenly and rises uniformly. It becomes warm. Therefore, the heating performance of the burner plate 22 to the plate fin group 31 is improved,
Uniform heat is transferred to the uniform heat transfer section 31 of the plate fin group 31.
The heat is transmitted evenly and substantially simultaneously from a to the water supply pipe 32, and a predetermined heat exchange is quickly performed. As a result, the hot water temperature rises quickly, and the secondary effect is that hot water is supplied at the set temperature from the beginning of operation.

Although this embodiment has such an effect, the through holes 1 of the current plate 100 can be formed without preparing any special members.
It is only necessary to change the arrangement state of 00a to be coarse or dense depending on the shape of the uniform heat transfer portion 31a, and the structure can remain simple, which is also advantageous in terms of cost.

Furthermore, when the temperature control knob is operated to increase the amount of hot water or the temperature of hot water, the amount of fuel gas supplied increases suddenly.
Due to the densely arranged arrangement of the through holes 100a, when the fuel gas passes through the rough portions of the through holes 100a, the flame rises from the burner plate 22 due to the momentum of the increase in the amount of fuel gas. An unstable state such as flickering does not occur, and a stable flame is obtained, contributing to good heating performance. In this case, the same effect as described above can be obtained even if the gas amount is rapidly increased after the sagging point instead of operating the temperature control knob.

Note that the originally existing through holes of the current plate 100 may be left as they are, and only the through holes in the region facing the peak M of the uniform heat transfer section 31a may be arranged in a rough arrangement. In this case, only the through holes in the area section facing the valley of the uniform heat transfer section 31a may be arranged in a dense array.

In addition, by changing the size of the diameter of the through hole in the current plate,
It is also possible to divide the holes into a large-diameter transparent hole group and a small-diameter transparent hole group, with the former corresponding to the valleys of the uniform heat transfer portion and the latter corresponding to the peaks.

Further, in the above embodiment, water is used as the working fluid, but air may be used in the heating device. Further, in the above embodiment, a heat exchanger tube having an equicircular cross section is used, but the present invention is not limited to this, and for example, a heat exchanger tube having an elliptical cross section may be used. In this case, the shape of the constant heat transfer portion also exhibits an elliptical shape.

In addition, various changes may be made in the specific implementation without departing from the gist of the invention.

[Brief explanation of drawings]

Fig. 1 is a side sectional view showing an instantaneous gas water heater as a forced air combustion device of the present invention, Fig. 2 is an enlarged vertical sectional view of the main parts, and Fig. 3 is a front sectional view showing the instantaneous gas water heater. Figure 4 is a front view of the instantaneous gas water heater, Figure 5 is a perspective view of the exhaust pan attached to the instantaneous gas water heater, and Figure 6 is an exhaust hood attached to the instantaneous gas water heater. 7 is a side sectional view of FIG. 6, and FIG. 8 is a perspective view of a shielding plate attached to the instantaneous gas water heater. In the figure, 1... Instantaneous gas water heater (forced air combustion device), 3... Heat exchanger, 22... Burner plate (burner), 31... Plate fin group (heat transfer fins),... Spout port (spout hole), 31a...
Equal heat transfer part, 32... Water supply pipe (heat transfer pipe), 100...
... Current plate, 100a... Through hole, M... Mountain portion (convex portion), V... Valley portion (concave portion).

Claims (1)

[Claims] 1. A plate-shaped burner that is provided with a large number of ejection holes and arranged horizontally, and that forms a flame by igniting supplied fuel gas, and a transmission through which a working fluid such as water passes through the inside. A heat transfer fin is provided on the outer periphery of the heat transfer tube, and the heat transfer fin has a uniform heat transfer portion whose lower outer peripheral edge is uneven according to the outer diameter of the heat transfer tube, and is provided in parallel above the burner. A forced air combustion device comprising: a heat exchanger heated by the flame from the burner; and a baffle plate having a group of through holes arranged below the burner in parallel with the burner; A forced air combustion device characterized in that the opening of the through hole of the current plate is set to be small for the convex portion of the uniform heat transfer portion of the heat transfer fin, and large for the concave portion.