JPH10300002A - Water-tube boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat transfer efficiency without increase in the heat transfer area by effectively arranging a heat transfer surface. SOLUTION: A portion inside a water tube array 4 built by arranging water tubes 3 for communication between an upper header and a lower header in a ring is provided to form a combustion chamber 5 and a combustion gas in the combustion chamber 5 is discharged from a flue 7. In a water-tube boiler thus arranged, the water tubes 3 are arranged in a half ring as opposed to a part of the first water tube array 4 built by arranging the water tubes 3 in a ring to dispose a second water tube array 10. A combustion chamber 11 is formed extending to a flue 7 from the combustion chamber 5 between the second water tube array 10 and the first water tube array 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water tube boiler having a structure in which an upper header and a lower header are connected by a number of water tubes.

[0002]

2. Description of the Related Art FIGS. 6 and 7 show the general structure of a conventional water pipe boiler of this type. FIG.
Is a cross-sectional view.

As shown in FIG. 1, an annular upper header 1 and a lower header 2 are arranged vertically at a predetermined interval, and the upper header 1 and the lower header 2 are vertically arranged. The plurality of water tubes 3 extend to communicate with each other. The water tubes 3 are arranged annularly in a state of being separated from each other at a predetermined pitch to form a water tube array 4, and the inside of the water tube array 4 is a combustion chamber 5. And, on the upper end surface of the combustion chamber 5,
A burner 6 as a combustion device is provided, and a combustion gas passage 11 is formed between the water pipe row 4 and the casing 8 by surrounding the outside of the water pipe row 4 with a casing 8 provided with a flue 7. Thereby, the water in the water pipe 3 is heated by the combustion gas of the burner 6, and is taken out as steam from the upper header 1.

As described above, the water pipes 3 are arranged annularly to form a water pipe row 4, and the inside of the water pipe row 4 is used as a combustion chamber 5 to improve the combustion efficiency of a heating means such as a burner 6. Can be.

Here, in general, heat exchange between the water pipe 3 and the combustion gas is performed better when the flow direction of the combustion gas and the axis of the water pipe 3 are orthogonal to each other than when the two are parallel or oblique. Is known to be. This is because in the orthogonal state, a vortex is easily formed behind the water pipe 3 by the flow of the combustion gas, and the heat transfer coefficient due to the turbulent flow is improved.

[0006]

However, in the conventional water pipe boiler having such a structure, the combustion gas of the burner is jetted in parallel with the axis of the water pipe, so that the combustion gas passing through the gap between the water pipes. However, there is a problem in that heat is transferred obliquely to the axis of the water pipe, and is discharged from the flue through the combustion gas passage, so that sufficient heat transfer efficiency cannot always be obtained. Was.

[0007] In order to improve the heat transfer coefficient, it is effective to increase the speed of the combustion gas. However, in the conventional water tube boiler, soot is clogged in the gap between the water tubes, and the combustion becomes difficult. There is a problem that rust is generated due to the dew of the gas, and the gap between the water pipes cannot be made narrower than a limited range. In addition, since a large number of such gaps are provided on the entire circumference of the annular water pipe row, the flow rate of the combustion gas flowing between the water pipes cannot be made higher, and a certain amount of improvement is required to improve the heat transfer efficiency. At present, there were limitations.

The present invention has been made in view of the above circumstances, and a water pipe boiler capable of improving the heat transfer efficiency without increasing the heat transfer area by effectively arranging the water pipe rows of the boiler. The purpose is to provide.

[0009]

According to the first aspect of the present invention, a combustion chamber is formed inside a water tube row formed by annularly arranging water tubes communicating the upper header and the lower header. In a water tube boiler configured to discharge indoor combustion gas from a flue, a first structure in which the water tubes are arranged in a ring shape.
The water pipes are arranged in a semi-annular manner so as to face a part of the water pipe row of the second water pipe row, and a second water pipe row is disposed between the second water pipe row and the first water pipe row. A water tube boiler, wherein a combustion gas passage extending to a road is formed.

With this configuration, the combustion gas burned in the combustion chamber flows through the combustion gas passage between the annular first water pipe row and the semi-annular second water pipe row. Inside, the flow direction of the combustion gas and the axis of the water pipe are orthogonal to each other, so that effective heat transfer can be performed and the heat transfer efficiency can be improved.

The invention according to claim 2 is characterized in that the water pipes forming the first water pipe row and the water pipes forming the second water pipe row are arranged so as to be shifted from each other by a half pitch angle in the circumferential direction. The water pipe boiler according to claim 1, wherein With this configuration, a circular water pipe in the first water pipe row is provided,
Since the circular water pipes of the second water pipe row are alternately arranged, the combustion gas passage can be formed narrow and long in a zigzag manner. Thereby, the heat transfer efficiency can be further improved.

[0012]

FIG. 1 is a block diagram showing an embodiment of the present invention.
A description will be given based on FIGS. 1 and 2 are views showing a structure of a water tube boiler according to a first embodiment of the present invention, wherein FIG. 1 is a transverse sectional view and FIG. 2 is a longitudinal sectional view.

As shown in FIG. 1, an upper header 1 and a lower header 2 which are both formed in an annular shape are arranged at predetermined intervals vertically, and these upper header 1 and lower header 2 are They are connected by a number of water tubes 3. Here, many water pipes 3
Are closely arranged in a ring shape to form a first water tube row 4. The inside of the pipe wall of the annular water pipe row 4 is a combustion chamber 5, and the inside of the upper header 1 is
A burner 6 for forming a flame as a combustion device is provided toward the combustion chamber 5.

Outside the annular first water pipe row 4, semi-annular water pipes 3 are arranged in close contact with each other to form a second water pipe row 10. A combustion gas passage 11 is formed between the pipe wall and the pipe wall of the annular water pipe row 4. Furthermore, the outside of the tube wall of the semi-annular second water pipe row 10 and the semi-annular water pipe row 1 of the annular first water pipe row 4
A casing 8 having a flue 7 at one end is provided on the outside of the tube wall where there is no zero, and a heat insulating material 12 is provided on the outside thereof.
Is provided.

The combustion chamber 5 and the combustion gas passage 11 communicate with the combustion gas passage 11 between the semicircular second water pipe row 10 and the annular first water pipe row 4 opposed thereto. The opening 13 is provided on the flue 7 side with an opening 14 for communicating the combustion gas passage 11 with the flue 7. Thereby, the combustion gas flows into the combustion gas passage 11 from the opening 13 and flows along the passage 11, and then passes through the opening 14 and is guided to the flue 7.

Here, in this embodiment, the annular water pipe row 4 is constituted by arranging the water pipes 3 with different radii of the radii DP1 and DP2, and the semi-annular second water pipe row 10 has the radius The water pipes 3 are arranged by DP3.
Can be set to any value between the other diameter DP2 and the radius DP3 of the second water pipe row 10.

Next, the operation of the water tube boiler having the above structure will be described. The combustion gas burned in the combustion chamber 5 is the first annular gas.
After reaching the combustion gas passage 11 through the opening 13 provided between the water pipe row 4 and the water pipe wall of the semi-annular second water pipe row 10, the water pipe 3 and the semi-annular The heat is exchanged between the water pipes 3 constituting the second water pipe row 10, and the flue gas 7 passes through an opening 14 provided between the annular first water pipe row 4 and the semi-circular second water pipe row 10. Head to. As described above, in the combustion gas passage 9, the combustion gas flows in the direction orthogonal to the axis of the water pipe 3 to perform heat exchange, thereby improving the heat transfer efficiency.

FIG. 3 is a view showing the structure of a water tube boiler according to a second embodiment of the present invention. The difference from the first embodiment of this embodiment is that the water tubes 3 are separated by a predetermined distance. The water tubes 3 are arranged in a semi-annular shape, and the water tubes 3 are connected by fins 15 to form a second water tube row 10a.
The water pipe 3 forming the water pipe row 10a and the water pipe 3 forming the annular water pipe row 4 are arranged so as to be shifted from each other by a substantially half pitch in the circumferential direction.

By arranging the water pipes of the water pipe row facing each other so as to be shifted by about a half pitch, circular water pipes can be arranged alternately. In other words, the water pipes of the second water pipe row can be arranged in the recesses between the water pipes of the first water pipe row 4 which are formed in close contact with the water pipes. Thereby, the combustion passage can be made narrow and long equivalently in a zigzag manner, so that the heat transfer efficiency can be further increased.

FIG. 4 is a view showing the structure of a water tube boiler according to a third embodiment of the present invention. The difference from the second embodiment of the present embodiment is that the water tubes 3 are separated by a predetermined distance. In that the water tubes 3 are connected by fins 16 to form a water tube row 4a. In this embodiment, as in the second embodiment, the heat transfer efficiency can be increased by shifting the water pipes of the opposing water pipe rows by a half pitch.

FIG. 5 is a view showing the structure of a water pipe boiler according to a fourth embodiment of the present invention. The difference of the second embodiment from the first embodiment is that The point is that a small-diameter water pipe 3a and a large-diameter water pipe 3 are arranged in close contact with each other in a ring shape, and a ring-shaped water pipe row 4b is formed. Also in such a structure, since the combustion gas passage 11 can be made narrower and longer equivalently, the equivalent heat transfer area can be increased and the heat transfer efficiency can be improved.

[0022]

As described above, according to the present invention,
By arranging a semi-annular second water pipe row facing a part of the annular first water pipe row and forming a combustion gas passage between the two water pipe rows, the heat transfer efficiency is improved, whereby the heat transfer efficiency is improved. The equivalent heat transfer area can be increased, and the boiler efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a water tube boiler according to a first embodiment of the present invention.

FIG. 2 is also a longitudinal sectional view.

FIG. 3 is a cross-sectional view showing a water tube boiler according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a water tube boiler according to a third embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a water tube boiler according to a fourth embodiment of the present invention.

FIG. 6 is a longitudinal sectional view showing a conventional water tube boiler.

FIG. 7 is also a transverse sectional view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper header 2 Lower header 3, 3a Water pipe 4, 4a, 4b Water pipe row 5 Combustion chamber 10, 10a Second water pipe row 11 Combustion gas passage 13, 14 Opening 15, 16 Fin

Claims (2)

[Claims] 1. A combustion chamber is formed inside a water tube row formed by annularly arranging water tubes communicating an upper header and a lower header, and combustion gas in the combustion chamber is discharged from a flue. In a water pipe boiler, a second water pipe row is arranged by arranging water pipes in a semi-annular manner so as to face a part of a first water pipe row constituted by arranging the water pipes in an annular manner. A water pipe boiler, wherein a combustion gas passage extending from the combustion chamber to a flue is formed between the water pipe boiler and the first water pipe row. 2. A water pipe constituting the first water pipe row and a second water pipe.
The water pipe boiler according to claim 1, wherein the water pipes constituting the water pipe row are arranged so as to be shifted from each other by a half pitch angle in the circumferential direction.