JPS61243203A - Steam generator - 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 The present invention relates to a steam generator having a small diameter and a connoisseur structure.

For example, if the bottom of the well is flat, the diameter must be small to match the size of the well, and the length must be as small and compact as possible to facilitate insertion into the well and transportation to the well. is requested to do so.

A steam generator capable of meeting the above requirements has been proposed, for example, in Japanese Patent Application No. 59-61184. This is done by installing a combustor at the upper end of the cylindrical can mouth and connecting a large number of evaporator tubes hanging vertically from the annular water supply pipe header to form a radiant heat transfer section that is a cylindrical water cooling wall. A compact configuration that shortens the overall length of the generator without reducing the heat transfer area by reducing the outer diameter and providing a convection heat transfer section with the evaporation tube bent inward following the radiant heat transfer section. It becomes. 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 the convection heat transfer section, the long and thin evaporation tubes are flexible and difficult to assemble, and also due to thermal expansion during use. There are problems such as deformation and undesirability in terms of forming a uniform gas flow path. In addition, an expansion joint is provided between the lower end of the can mouth and the steam collecting pipe to absorb the difference in thermal expansion between the can mouth and the evaporator pipe, but the fixed upper end of the can mouth of the steam generator is This is not a desirable structure because the expansion joint must have a structure that can withstand a considerable load when the equipment is suspended or when the steam collecting pipe is fixed to support the load of the equipment.

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. In addition, in order to absorb the difference in thermal expansion between the can mouth and the evaporation tube,
A loop is formed at the end of the evaporation tube.

An embodiment of the present invention will be described below with reference to the drawings. 1 in the diagram
1 is a cylindrical can mouth, and a head connecting metal fitting 5 is fixed to a fixed metal fitting 1a provided at the upper end with gel adhesive. The heating charge, water supply,
A supply pipe 6 for air, etc. is connected thereto, and an annular water supply header 2 and a combustor 4 are provided on the lower side. Water supply pipe header 2
A cylindrical evaporation tube section 3 is constructed by vertically disposing a large number of evaporation tubes 31. The evaporator pipe section 3 is provided with a gap forming a combustion exhaust gas passage 11 between it and the inner wall of the can housing, and the exhaust gas is discharged through the exhaust gas pipe 7 connected to the connecting metal fitting 5. The upper part of the section 3 is connected to the radiant heat transfer section R, which is a cylindrical water-cooled wall, by directly connecting the evaporation tubes 31 to each other, or by gas-tight seal welding through the connecting members 3 and 3 as shown in FIG. is formed. At the lower end, as shown in FIG. 2, the two evaporator tubes 31.31 are combined into one evaporator tube 32, thereby forming a combustion exhaust gas passage between the evaporator tubes 32.32. The evaporation tube 32 is U-bent 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-bends of the evaporator tubes 32 are of two types: a 3A type in which the radial spacing between the evaporator tubes in the cross section is large, and a 3B type in which the radial spacing is narrow, and the 3A types and 3Bfi are arranged alternately in the circumferential direction. This allows a large number of evaporation tubes 32m, 32b and 33ts, 33b to be arranged within a narrow cross-sectional area. In this case, the type 3A is supported by two supporting metal fittings 20k in the direction of the evaporator tube, as shown in FIGS. 3 and 5. The supporting hardware 20 is provided at appropriate intervals in the longitudinal direction. The supporting hardware 20 includes a combination of L-shaped hardware 21h, 21m welded to the evaporation tube 31.3JK, a T-shaped hardware 22a welded to the upward evaporation tube 32m, and an L-shaped hardware 23* welded to the evaporation tube 32m. , 23*, and downward evaporation tube 3
3a in combination with T7 metal fittings 24m welded to the evaporator tube 3a, the evaporator tubes are configured to support the evaporator tubes while maintaining a predetermined distance from each other in the radial direction while allowing movement in the axial direction of the can due to thermal expansion of each evaporator tube. It has become. In addition, as for the 3B type, as shown in FIG.
b is supported by the radial support hardware 20B.

As shown in FIG. 3, the support hardware 20B is attached at a different position from the support hardware 20 in the longitudinal direction of the tube to avoid an increase in ventilation resistance due to the support hardware. Support hardware 20B
is an L-shaped metal fitting 21b welded to the evaporation tube 31.31.

21b and the flat plate 2 welded to the upward evaporation tube 3'2b.
2b, and a combination of U-shaped hardware 23b, 23b bath-bonded to the evaporation tube 32b and a flat plate 24b welded to the downward evaporation tube 33b. The downward evaporation tubes 33 m and 33 b of types 3A and 3B are connected to each other via an inverted T-shaped metal fitting 25 .

A loop 13 is formed at the end of the evaporator tubes 33h and 33b to absorb the difference in thermal expansion between the can opening 2 and the evaporator tube section 3. The ends of these evaporation tubes are connected to a tube plate 8 fixed to the lower end of the can mouth 2, so that steam flows into a steam collecting tube 9.

By the way, the upper end of the evaporation pipe section 3 is connected to the header 2, and this header is connected to the can mouth 2 via the head metal fitting 5 and the fixed metal fitting 1a.
On the other hand, the lower end is fixed to the can opening 2 via the tube plate 8, so even if an external force is applied to the can opening 2 during installation or removal of this device, no undue force will be applied to the evaporator tube section 3. It has no effect. On the other hand, due to the temperature difference between the can mouth 2 and the evaporation pipe section 3,
When the evaporator tube section 3 expands, the evaporator tube's zero in the convection heat transfer section
The 472 portion is bent with a small curvature and cannot absorb the expansion difference very much, but it can be sufficiently absorbed by the loop 13 with a large curvature formed at the end of the vapor deposition.

Next, to assemble this device, first the annular header 2 and the evaporator tube section 3 are divided into two halves, welded the inner and outer surfaces and assembled the convection heat transfer section, 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 33m. 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. I can do it. In addition, a loop was formed at the end of the evaporator tube to absorb the difference in thermal expansion between the can mouth and the evaporator tube.
This equipment can be installed and removed without any restrictions.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing one embodiment of the device of the present invention, Fig. 2 is an explanatory view showing the state of connection of the evaporation tubes in the direction of the arrows ■-■ in Fig. 1, and Fig. 3 is a diagram of the convection heat transfer section. An explanatory diagram showing the U-bend state and support state of the evaporator tube, Fig. 4 is an enlarged cross-sectional view taken along arrows IV-IV in Fig. 1, and Figs. 5 and 6 show support for 3A type and 3B type evaporation tubes, respectively. It is an enlarged explanatory view of a state where it is supported by hardware. DESCRIPTION OF SYMBOLS 1... Can opening, 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, 32m, 32b, 33*, 33b-
...Evaporation tube, 20, 20B...Support hardware, R...
Radiation heat transfer section, C... convection heat transfer section. Applicant's agent Takehiko E, patent attorney Figure 5
Figure 6 Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1) A cylindrical can casing with a combustor provided at its upper end, and a cylindrical can provided with a gap between the can casing and the inner wall of the can casing, which serves as a passage for combustion exhaust gas. , and a steam collecting pipe connected to the end of the evaporator pipe, the evaporator pipe being composed of a large number of evaporator pipes vertically installed on an annular water supply header,
The upper parts of these evaporation tubes are connected to each other to form a radiant heat transfer section that is a cylindrical water-cooled wall, and at the lower end, the evaporation tubes are combined into one and U-bended upward and then further inward. In one which is U-bent downward to form convection heat transfer and whose end is connected to the steam collecting pipe,
A steam generator characterized in that the vertically U-bent evaporator tube of the convection heat transfer section is supported by a radial support metal fitting 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.