JPH0335563B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steam generator having a small diameter and compact configuration.

For example, in the case of a bottom-hole boiler, the diameter needs to be small to match the size of the well, and the length should also be as small and compact as possible to facilitate insertion into the well and transportation to the well. This is requested.

A steam generator capable of meeting the above requirements has been proposed, for example, in Japanese Patent Application No. 59-61184. This is achieved by installing a combustor at the upper end of the cylindrical can, and connecting a large number of evaporator tubes hanging vertically from the annular water supply pipe header to form a radiant heat transfer section, which is a cylindrical water cooling wall. By reducing the diameter and providing a convection heat transfer section with the evaporation tube bent inward following the radiation heat transfer section, we have achieved a compact configuration that shortens the overall length of the generator without reducing the heat transfer area. It's summery. By passing the combustion exhaust gas through the gap between the inner wall of the can and the evaporator tube, the feed water is heated and the exhaust gas output temperature is lowered.

However, when arranging a large number of U-bent evaporation tubes in a relatively short gap in a convection heat transfer section, the long and thin evaporation tubes are easily bent, making assembly and construction troublesome.
Further, there are problems such as deformation due to thermal expansion during use, making it difficult to form a uniform gas flow path. In addition, an expansion joint is provided between the lower end of the can enclosure and the steam collecting pipe to absorb the difference in thermal expansion between the can enclosure and the evaporator pipe, but the steam generator is fixed at the upper end of the can enclosure. When the equipment is suspended or the steam collecting pipe is fixed to take on the load of the equipment, the expansion joint must have a structure that can withstand a considerable load, which is not a preferable structure.

The object of the present invention is to provide a steam generator capable of solving the above-mentioned problems.

A feature of the steam generator of the present invention is that the evaporator tube, which is U-bent in the vertical direction of the convection heat transfer section, is supported by radial supporting metal fittings while allowing thermal expansion movement in the can axis direction. Additionally, a loop is formed at the end of the evaporator tube in order to absorb the difference in thermal expansion between the can enclosure and the evaporator tube.

An embodiment of the present invention will be described below with reference to the drawings. In the figure, reference numeral 1 denotes a cylindrical can enclosure, and a head connecting metal fitting 5 is fixed with a bolt to a fixed metal fitting 1a provided at the upper end. Supply piping 6 for fuel, water, air, etc. is connected to the upper side of this connecting hardware, and an annular water supply header 2 and a combustor 4 are provided to the lower side. A cylindrical evaporation pipe section 3 is constructed by vertically disposing a large number of evaporation pipes 31 on the water supply pipe header 2. The evaporator pipe section 3 is provided with a gap between it and the inner wall of the can housing to form a combustion exhaust gas passage 11, and the exhaust gas is discharged through an exhaust gas pipe 7 connected to the connecting metal fitting 5.

The upper part of the evaporation tube section 3 can connect the evaporation tubes 31 directly to each other, or can be connected to a connecting member 31 as shown in FIG.
The radiant heat transfer portion R, which is a cylindrical water-cooled wall, is formed by gas-tight seal welding through the a. Then, at the lower end, two evaporation tubes 3 are installed as shown in FIG.
1 and 31 into one evaporator tube 32, a combustion exhaust gas passage is formed between the evaporator tubes 32 and 32. The evaporator tube 32 is U-bended inwardly upward and then further inwardly downwardly to form a convection heat transfer section C whose cross section is shown in FIG. In this case, the U-bend of the evaporator tubes 32 is such that the radial distance between the evaporator tubes in the cross section is large.
There are two types: 3A type and 3B type with narrow intervals, and the 3A type and 3B type are arranged alternately in the circumferential direction, so that a large number of evaporation tubes 32a, 32b and 33a, 3 are arranged within a narrow cross-sectional area.
3b can be arranged. In this case 3A
About the mold As shown in FIGS. 3 and 5, the two evaporation tubes 31, 31, and the upward evaporation tube 32a and the downward evaporation tube 33a, which are combined into one, are supported by a radial support metal fitting 20A. ing. The supporting hardware 20A is provided at appropriate intervals in the longitudinal direction. The supporting hardware 20A includes the evaporation tube 31,
A combination of L-shaped metal fittings 21a, 21a welded to 31 and T-shaped metal fittings 22a welded to upward evaporation tube 32a, and L-shaped metal fittings 23a, 23a welded to evaporation tube 32a and welded to downward evaporation tube 33a. The evaporator tubes are configured in combination with the T-shaped hardware 24a, which allows each evaporator tube to move in the can axis direction due to thermal expansion, while supporting the evaporator tubes while maintaining a predetermined distance from each other in the radial direction. ing. Also 3B
Regarding the mold, as shown in Fig. 6, two evaporation tubes 3 are used.
1, 31 and the upper evaporation tube 32 combined into one
b and the downward evaporation tube 33b are supported by a radial support metal fitting 20B. Support hardware 20B
As shown in FIG. 3, the supporting hardware 20 is
It is installed in a different position from A to avoid an increase in ventilation resistance due to supporting hardware. Support hardware 2
0B is a combination of the L-shaped metal fittings 21b, 21b welded to the evaporation tubes 31, 31 and the flat plate 22b welded to the upward evaporation tube 32b, and the combination of the U-shaped metal fittings 23b, 23b welded to the evaporation tube 32b and the downward facing evaporation tube 32b. The evaporation tube 33b and the flat plate 24b are welded together. And type 3A and 3B
The downward evaporation tubes 33a and 33b of the mold are interconnected via an inverted T-shaped metal fitting 25.

A loop 13 is formed at the end of the evaporation tubes 33a, 33b to absorb the difference in thermal expansion between the can enclosure 2 and the evaporation tube section 3. The ends of these evaporation tubes are connected to a tube plate 8 fixed to the lower end of the can enclosure 2, so that steam flows into a steam collecting tube 9. by the way,
The upper end of the evaporator tube section 3 is connected to the header 2, and the header is fixed to the can enclosure 2 via the head fitting 5 and the fixed fitting 1a, while the lower end is connected to the can enclosure 2 via the tube plate 8.
Therefore, even if an external force is applied to the can enclosure 2 during installation or removal of the device, no unreasonable force will be applied to the evaporator tube section 3. On the other hand, when the evaporator tube section 3 expands due to a temperature difference between the can enclosure 2 and the evaporator tube section 3, the U-bend section of the evaporator tube in the convection heat transfer section is bent with a small curvature, and absorbs the difference in expansion. However, it can be sufficiently absorbed by the loop 13 of large curvature formed at the end of the vapor deposition.

Next, in the assembly of the present invention, first, the annular header 2 and the evaporator tube part 3 are divided into two halves, and the inner and outer surfaces are joined and the convection heat transfer part is assembled, and then the two halves are overlapped and connected. The parts are welded on the outside and assembled into one body. In this case, since the inverted T-shaped hardware 25 (Fig. 6) is located at the center of the convection heat transfer section, one side of the inverted T-shaped hardware 25 located at the dividing surface cannot be welded to the evaporation tube 33a. Since the other side of this evaporation tube 33a is welded to the next inverted T-shaped metal fitting, there is no particular problem.

The steam generator of the present invention is as described above, and has a structure in which the evaporation tube of the convection heat transfer section is supported by radial support hardware, which facilitates assembly and construction, and also makes the gas flow uniform. Can be done. Furthermore, since a loop for absorbing the difference in thermal expansion between the can enclosure and the evaporator tube is formed at the end of the evaporator tube, the device can be installed and removed without any restrictions.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an embodiment of the device of the present invention, Fig. 2 is an explanatory view showing a joined body of evaporation tubes in the - arrow direction of Fig. 1, and Fig. 3 is an evaporation of the convection heat transfer section. Explanatory diagram showing the U-bend state and support state of the pipe, No. 4
The figure is an enlarged sectional view taken in the direction of the arrows in FIG. 1, and FIGS. 5 and 6 are enlarged explanatory views of 3A type and 3B type evaporation tubes supported by supporting metal fittings, respectively. DESCRIPTION OF SYMBOLS 1... Can enclosure, 2... Annular water supply pipe header, 3... Evaporator pipe section, 4... Combustor, 8... Tube plate, 9... Steam collecting pipe, 11... Combustion exhaust gas passage, 13... Loop, 31... Evaporation tube, 32a, 32b, 33a,
33b... Evaporation tube, 20A, 20B... Support hardware, R... Radiation heat transfer section, C... Convection heat transfer section.

Claims (1)

[Scope of Claims] 1. A cylindrical can housing provided with a combustor at its upper end, and a cylindrical can housing provided with a gap between the can housing and the inner wall of the can housing to serve as a passage for combustion exhaust gas. an evaporation pipe section;
The evaporator tube section is composed of a steam collecting pipe connected to the end of the evaporator tube section, and the evaporator tube section is composed of a large number of evaporator tubes vertically installed on the annular water supply pipe header. In addition to forming a radiant heat transfer section that is a water-cooled wall, multiple evaporation tubes are combined into one at the lower end and are U-bended inward and upward, and then further inward and downward in a U-bend to form convective heat transfer. In the case where the end is connected to the steam collecting pipe, there is a U in the vertical direction of the convection heat transfer section.
1. A steam generator characterized in that the bent evaporator tube is supported by radial supporting metal fittings while allowing thermal expansion movement in the axial direction of the can. 2. The steam generator according to claim 1, wherein a loop for absorbing a difference in thermal expansion between the can enclosure and the evaporator tube is formed at the end of the evaporator tube.