JPS62155401A - Shell-and-tube type once-through boiler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a multi-tubular once-through boiler.

(Prior art) Conventionally, a large number of inner water pipes are arranged in a ring between a pair of upper and lower headers, and the outer water pipes are spaced appropriately from the inner water pipes so that the outer water pipes and the inner water pipes form a triangle. The inner fins are arranged vertically from the upper header in the gaps formed between the inner water pipes, and the outer fins are installed vertically from the lower header in the gaps formed between the outer water pipes. A multi-tube once-through boiler is known in which a gas passage is formed by the inner water tube, the outer wood tube, the inner fin, and the outer fin.

However, the water tubes used in this type of conventional multi-tube once-through boiler are bare tubes with smooth outer surfaces, and the combustion gas flows in a turbulent state, but there is a boundary layer on the water tubes and fin surfaces. is formed, which acts as a heat transfer resistance and limits the heat transfer efficiency to a relatively low value.

Therefore, in order to increase the heat transfer efficiency in a device with this kind of configuration, it is necessary to increase the heat transfer area by increasing the diameter or length of the water pipe, and it is necessary to increase the size or installation of the force device. This will result in an increase in space.

(Purpose of the Invention) The present invention aims to improve the problems pointed out in the above section of the prior art. The purpose is to provide a once-through boiler.

(Means for Achieving the Object) As a means for achieving the above object, the present invention provides a projection body extending in a circumferential direction or a spiral direction over an appropriate range or the entire circumference on the outer surface of the water pipe. It was formed.

(Function) In the present invention, by the above-mentioned means, the aforementioned boundary layer of the combustion gas flowing in the gas passage is divided by the protrusions formed on the outer surfaces of the inner water pipe and the outer water pipe, and as a result, a violent vortex is generated. The effect is that the heat transfer efficiency between the combustion gas and the heat transfer surface is promoted.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

1 and 2 show a multi-tubular once-through boiler Z according to an embodiment of the present invention. This once-through boiler Z has a double-walled container-shaped boiler body 1 which is made of a casing 12 formed in a substantially cylindrical shape and a heat insulating material 11 arranged concentrically within the casing 12. An upper header 3 and a lower header 4 are respectively provided, and a large number of inner water pipes 5, 5, (7)... and outer water pipes 6, 6, (5)... are provided between the pair of upper and lower headers 3, 4. , the valley inner water pipe 5°5, (5
) are located on the radially inner side and the outer water pipes 6, 6, (5), . In FIGS. 1 and 2, reference numeral 2 indicates a combustion device, 9 and 10 refractories placed at two positions above and below the boiler body 1, and 13 a flue.

The inner water pipes 5, 5, etc. are spaced apart from each other on the circumference with minute gaps R1, R,, (5), etc., as shown in Figs. It is connected to the upper header 3 and the lower header 4, respectively.

On the other hand, the outer water pipes 6, 6, . . . are arranged in a circumferential manner on the outside of the inner water pipes 5, 5, . ing.

Further, in this embodiment, the arrangement pitch θ of the inner water pipes 5, 5, etc. and the arrangement pitch angle θ2 of the outer water pipes 6, 6, etc. are set to the same pitch angle, and moreover, in these arrangement states, , each inner water pipe 5, 5, (7)... and each outer water pipe 6, 6, (7)... is 1/2 in the circumferential direction.
The relative positions between the two are set so as to be shifted by a pitch (θ=θ1/2=θ2/2).

Furthermore, in this embodiment, as shown in FIGS. 3 and 4, an annular pattern is formed on the outer surface 5a of the inner water tube 5 and the outer surface 6a of the outer water tube 6 along the circumference. A large number of extending protrusions 17 are formed at appropriate pitches in the longitudinal direction of the pipe.The protrusions 17 have a solid rectangular cross section.

Moreover, the gap R formed between each of the inner water pipes 5, 5...
, R, , (R1)... have inner fins 7.7, and gaps R2, R2 formed between the outer water pipes 6, 6...
, (R1)... are attached with outer fins 8, 8, (6)..., respectively. These inner fins 7.7, (7)... and outer fins 8, 8... are connected to two adjacent water pipes 5, respectively.
, 5 or water pipes 6, 6 in width. In addition, each of these inner and outer fins 7.8 is connected to two adjacent water pipes 5, 5 or 6 at each end.
, 6, the inner fin 7 is further fixed by welding its upper end to the upper header 3, and the outer fin 8 is further welded to its lower end to the lower header 4. Further, the internal space annularly surrounded by the inner fins 7, 7, and the inner water pipes 5, 5, is a combustion chamber 18, and above the combustion chamber 18, the combustion device 2 is installed. installed.

The inner fin 7 is hung downward from the lower surface of the upper header 3,
Further, the outer fin 8 is erected upward from the upper surface of the lower header 4. Furthermore, the inner fin 7 and the outer fin 8 are
They are arranged so as to overlap by a predetermined length in the radial direction.

Therefore, an elongated vertical gas passage 16 is formed between the inner and outer fins 7.8, the inner water tube 5, and the outer water tube 6.

At the lower end of this gas passage 16, there is a bottom gas passage 14 formed by a gap between the lower end of the inner fin 7 and the lower header 4.
is formed, and the gas passage 16 and the combustion chamber 18 are communicated with each other via the bottom gas passage 14. Further, an upper gas passage 1 formed of a gap between the upper end of the outer fin 8 and the upper header 3 is provided at the upper end of the gas passage 16.
5 is formed, and the gas passage 16 is communicated with the flue 13 via the upper gas passage 15.

Next, to explain the operation of the illustrated once-through boiler Z, in this once-through boiler Z, when the combustion device 2 is ignited, the combustion gas G generated in the combustion chamber 18 is transferred to the bottom gas passages 14, 14.
..., each inner water tube 5゜5... and inner fin 7.7
...and each outer water pipe 6,6... and outer fin 8,8
The gas rises in the gas passage 16 formed by the upper gas passages 15, 15, . . . and is discharged to the outside through the flue 13. When the combustion gas G rises in the gas passage 16, it comes into contact with the inner and outer water pipes 5, 5..., 6, 6,... and the inner and outer fins 7.7, -, 8, 8, (7)... Each water pipe 5
, 5 . . . , 6. It exchanges heat with the water in the can △ and acts to raise the temperature of the can water.

At this time, in this embodiment, the present invention is applied to provide protrusions 17 on the outer surfaces of the inner and outer can water pipes 5, 5..., 6, 6...
, 17, (5)... are formed in large numbers, so the gas passage 1
The combustion gas G flowing through each of these protrusions 17.17
, (7)..., the flow is disturbed. Therefore, almost the whole view of the gas flowing in the gas passage 16 is uniformly brought into contact with the heat transfer surface, and a higher level of transfer efficiency is obtained.In other words, this once-through boiler Z
The transmission can be carried out without increasing the size of the device by a simple means of forming protrusions 17, 17, (5), etc. on the outer surfaces of the inner and outer can water pipes 5, 5, 6, 6, and so on. This makes it possible to improve thermal efficiency.

In the above embodiment, as shown in FIG. 4, the protrusions 17 formed on the outer surfaces 5a, 6a of the inner and outer can water pipes 5, 6 are made of solid protrusions having a rectangular cross section. is formed in an annular shape over the entire circumference of the outer surface of the water pipe, but the present invention is not limited to this. For example, the cross-sectional shape may be a solid trapezoidal cross-section ( Fifth
Figure), solid triangular cross section (Figure 6), solid circular cross section (Figure 7)
), solid circular arc cross section (Fig. 8), solid sinusoidal wave cross section (
(Fig. 9), hollow rectangular cross section (Fig. 10), hollow trapezoidal cross section (Fig. 11), hollow triangular cross section (Fig. 12), hollow circular arc cross section (Fig. 13), hollow sinusoidal cross section (Fig. 14) Various shapes can be adopted as shown in Fig.). Further, regarding the formation range of the protrusion 17 in the circumferential direction, as in each of the above embodiments (instead of forming it over the entire circumference of the outer surface of the water pipe, it is formed only on a part of the circumferential direction of the outer surface of the water pipe). It can also be formed.

Furthermore, the direction in which the protrusion 17 is formed may be formed in a spiral direction along the outer surface of the water tube, for example, instead of being formed in an annular shape along the circumferential direction as in each of the above embodiments.

(Effects of the Invention) Next, to explain the present invention in detail, this multi-tube once-through boiler has protrusions formed on the outer surface of the inner water tube and the outer surface of the outer water tube, so that the inside and outside of the vagina can be When the combustion gas flows through the gas passage surrounded by the can water pipe and the inner and outer can fins, the flow of the combustion gas is disturbed by each of the projections, and the entire combustion gas is evenly distributed on the heat transfer surface. Therefore, compared to a conventional once-through boiler (which has a configuration in which no disturbance of the combustion gas in the gas passage can be expected), a higher level of heat transfer efficiency can be achieved, and the size of the equipment can be increased. The effect is that it can be easily realized without any inconvenience.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of a multi-tubular once-through boiler according to an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along the line ■-■ of Fig. 1, and Fig. 3 is an enlarged view of the main part of Fig. 2; FIG. 4 is an enlarged view of the water pipe, and FIGS. 5 to 14 are views of the shapes of other protrusions. l・・・・・・・・・・・・・・・・・・・・・・・・
・・Boiler body 2・・・・・・・・・・・・・・・・・
・・・・・・Combustion device 3・・・・・・・・・－・・・・・・
・・・・・・Upper header 4・・・・・・・・・・・・
・・・・・・・・・Lower pipe header 5・・・・・・・・・
・・・・・・・・・・・・・・・Inner water pipe 6・・・・・・
・・・・・・・・・・・・・・・・・・Outer water pipe 7・
・・・・・・・・・・・・・・・・・・・・・・・・
Inner fin 8・・・・・・・・・・・・・・・・・・
・Outer fin origin

Claims (1)

[Claims] 1. Annularly formed upper header (3) and lower header (4)
), a large number of inner water pipes (5), (5)... are spaced apart from each other at appropriate intervals (S_1) in the circumferential direction, and a large number of outer water pipes (6), (6)... are arranged as described above. Each inner water pipe (5),
(5) on the outside of and inside each of the water pipes (5), (
5) They are arranged in the circumferential direction at an appropriate interval (S_2) from each other, and the arrangement pitch angle (θ_1) of each of the inner water pipes (5), (5)... Arrangement pitch angle (θ_2) of water pipes (6), (6)...
) are the same, and each of the above inner water pipes (
5), (5)... and each of the inner water pipes (5), so that the outer water pipes (6), (6)... are shifted by 1/2 pitch, respectively.
(5)... and each of the outer water pipes (6), (6)..., and set the relative position in the circumferential direction of each of the inner water pipes (5), (5)...
In each of the inner gaps (R_1) and (R_1) formed between, there is an inner fin (7) hanging vertically from the upper pipe header (3).
, (7)..., and each of the outer gaps (R_2), (R_2)... formed between the outer water pipes (6), (6)... is installed upright on the lower header (4). The outer fin (8)
, (8)... are installed in a state where they overlap each other in an appropriate range in the radial direction, and each of the above-mentioned inner water pipes (5), (5)
The gas passage (16) is connected by the four members: ..., each of the inner fins (7), (7), and each of the outer water pipes (6), (6), and each of the outer fins (8), (8). A multi-tubular once-through boiler formed by forming a water pipe in the circumferential direction on the outer surface of each of the inner water pipes (5), (5)... and on the outer surface of each of the outer water pipes (6), (6)... A multi-tubular once-through boiler, characterized in that a protrusion (17) extending in a circumferential direction or a spiral direction is formed over an appropriate range or the entire circumference thereof. 2. The multi-tubular once-through boiler according to claim 1, wherein the protrusion (17) has a rectangular cross section. 3. The multi-tubular once-through boiler according to claim 1, wherein the protrusion (17) has a trapezoidal cross section. 4. The multi-tube once-through boiler according to claim 1, wherein the protrusion (17) has a triangular cross section. 5. The multi-tube once-through boiler according to claim 1, wherein the protrusion (17) has a circular cross section. 6. The multi-tube once-through boiler according to claim 1, wherein the protrusion (17) has an arcuate cross section. 7. The multi-tube once-through boiler according to claim 1, wherein the protrusion (17) has a sinusoidal cross section.