JPH0619923Y2 - Heat transfer tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to improvement of a horizontal value hairpin type heat transfer tube structure such as a waste heat boiler or an economizer for a boiler.

[Conventional technology]

FIG. 7 shows a sectional view of a horizontal hairpin type heat transfer tube portion of a conventional waste heat boiler or the like.

In FIG. 7, (1) is a heat transfer tube consisting of a hairpin part having a straight part in the horizontal direction, (2) is its joint part, (3) is an annular fin attached to the outer surface of the straight part, and (4) is Inner casing,
(5) is an outer casing, (6) is a heat insulating material or heat resistant material filled between the inner and outer casings, and (7) is a waste heat gas inlet.

Generally, a heat transfer tube having a shape as shown in Fig. 7 is used as a waste heat boiler or an economizer for the boiler.
Although there is already a technique in which an annular fin or the like is attached to the outer surface of the pipe and is used as an expanded heat transfer surface, the expanded heat transfer surface portion has been conventionally limited to the straight pipe portion due to the limitation in the production technology.

That is, the automatic fin planting machine was limited to planting fins on a straight pipe, and parts such as grips were required at both ends. Therefore, it has been extremely difficult to attach fins automatically or inexpensively in a considerable part including the bent portions at both ends thereof. I would like to design the entire length of the heat transfer tube so that it fits in the passage of the waste heat gas that should be used, including this bent portion, but then the hot gas bypasses both ends of the heat transfer tube without fins and the fins are attached. The effect of the tube will also be halved.

Therefore, it is unavoidable in the past that an inner casing (4) is provided to limit the gas passage to the finned pipe section, and further a casing (5) is provided outside the inner casing (4) to seal the gas so that the waste gas does not leak outside. In addition, the material is designed to be filled with a material for keeping heat and insulating between the inner casing and the outer casing.

[Problems to be solved by the invention]

In the conventional heat transfer tube structure as described above, the inner casing (4)
It is very difficult to assemble and it takes time,
(6) Gas entered the inside, and when the load was reduced or stopped, the gas was condensed in this part, which often caused corrosion of the heat transfer tube.

Furthermore, the heat transfer effect was largely wasted mainly in the bent portion of the heat transfer tube that entered the casing.

[Means for solving problems]

In view of the above, the present invention minimizes the bypass of the hot gas at the bent portions of both ends while inserting all the heat transfer tubes in the gas passage in order to eliminate the disadvantages and wasteful points of the conventional heat transfer tube structure. With the purpose of providing a heat transfer tube, in a hairpin-shaped heat transfer tube in which the straight water pipe part is used as an enlarged heat transfer pipe surface and the part is placed in water, the entire part including the bent parts at both ends is placed in the hot gas passage. Install the fins (8) on the bent portion of the heat transfer tube in the gap between the expanded heat transfer surface of the straight water pipe and the side casing, and further install the closing plate (9) on the inner surface of the inner casing to install the fins (8) and the closing plate ( 9) to provide a heat transfer tube with both attached.

Moreover, in the bent portion of the water pipe, the fins adjacent to the heat transfer pipe
As shown in FIG. 6, (8) and (8 ') are mounted so as to have desired acute angles with opposite slopes to the horizontal [Embodiment] Next, the present invention will be described with reference to the drawings.

FIG. 1 is a side view of a part of an embodiment of a closing plate according to the present invention, in which a horizontal fin (8) is attached to the heat transfer tube by welding so as to close a bypass of waste gas, and the tube is further attached. A blocking plate (9) which also functions as a support for the heat transfer tube (1) is attached to the inner casing (4) below the bent portion.

Thus, the space between the heat transfer tubes is maintained, and bypass of the gas flow at the bent portions at both ends is prevented. Figure 4 is Figure 1
III _A cross-sectional view, Fig. 5 shows a III _B sectional view of FIG. 1. Although FIG. 4 shows the case of being horizontal, (8), (8 '), (8 ") and (8) are fins of the heat transfer tube, and (8) and (8') are adjacent fins.

Fig. 2 is a side view of a part of a straight water pipe, in which the same horizontal fins (8) as in Fig. 1 are welded to all pipe bends, and the amount of waste gas passing through the bypass is better. There is an advantage that it can be reduced, but the cost is higher.

FIG. 3 is a side view of a part of another embodiment of the present invention, in which a flat plate (9) is attached to the inside of the inner casing (4) to prevent waste gas from bypassing and the heat transfer tube (1). It keeps the space between, and may be attached above and below the bent portion of the pipe.

As shown in FIGS. 1, 2 and 3, when the fins (8) attached to the heat transfer tubes are arranged horizontally in the vertical direction, the present invention is shown in FIG. 6 (8), (8 '). As shown in the figure, the fins that are adjacent to each other are attached at the opposite angles to each other, and the action of the fins is greater.

FIG. 8 shows fins (8) adjacent to each other in the heat transfer tube shown in FIG.
FIG. 8 is an explanatory view of an embodiment in which (8 ′) is provided so as to have desired acute angles (α) and (α ′) in opposite directions with respect to the horizontal surface of the vertical side surface casing (4).

The fin (8) and the closing plate (9) of the present invention may be attached by welding or may be bolted to the water pipe (1), and an appropriate attachment method may be adopted. .

[Effect of device]

According to the present invention, the bypass of waste gas is reduced, the entire length of the heat transfer tube is effectively alive, the corrosion in the casing is eliminated, the disorder of the arrangement of the heat transfer tubes is corrected, and the performance as a heat transfer tube is maintained forever. The fins can be held, and if the fins are only horizontal, a step may be formed, or the clearance may increase due to the accuracy of mounting, and the amount of gas leakage in this part may increase. The above disadvantages can be prevented by making the fins (8), (8 ') (Fig. 6) (Fig. 8) in opposite directions to the horizontal plane of the vertical side casing (4), Since the entire amount of gas passes through the fin portion with high heat transfer efficiency, high performance is achieved as a whole, and the effect is great.

[Brief description of drawings]

FIG. 1 is a side view of a part of an embodiment of the present invention, FIG. 2 is an example in which a fin is attached only horizontally, and FIG. 3 is a side view of a part of an embodiment of a closing plate of the present invention. Figure 4 is a sectional view of III _a of Figure 1, Figure 5 is a cross-sectional view of FIG. 1 III _B, 6 fins figure attached to the heat transfer pipe bent portion of the present invention (8), (8 ' ) Different from the horizontal direction, FIG. 7 is a view of a heat transfer tube of a conventional waste heat boiler, and FIG. 8 is a fin (8), (8 ') adjacent to the heat transfer tube shown in FIG. 2) is an explanatory view of an embodiment in which the desired vertical angles (α) and (α ′) are provided in opposite directions with respect to the horizontal surface of the vertical side casing (4). 1 ... Heat transfer pipe, 2 ... Joint part 3 ... Annular fin provided in straight part of heat transfer pipe 4 ... Inner casing, 5 ... Outer casing 6 ... Heat insulating material or heat resistant material, 7 ... Waste heat gas Inlet 8, 8, ... Fin of the present invention, 9 ... Blocking plate

Claims (1)

[Scope of utility model registration request] 1. In a hairpin-shaped heat transfer tube in which the straight water pipe portion is used as an enlarged heat transfer surface and the portion is horizontally arranged, the entire portion including the bent portions at both ends thereof is housed in a hot gas passage to expand the straight water pipe. In the bent portion of the heat transfer tube in the gap between the heat transfer surface and the side casing, the adjacent fins (8), (8 ') of the heat transfer tube are connected to the horizontal plane of the vertical side casing at desired acute angles (in opposite directions). α), (α ′), and a blocking plate (9) attached to the inner surface of the inner casing.