JPH073182Y2 - Heat transfer acceleration fin for boiler - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to improvement in fin shape of a heat transfer tube with fins, and more particularly to fin shape of heat transfer tube with fins used in a multi-tube once-through boiler. .

[Conventional technology]

As is well known, the heat transfer tube surface of a heat exchanger such as a boiler is
Fins are attached for the purpose of promoting heat transfer.

For example, a fin of this kind in a multi-tube boiler has a substantially V-shape along the outer circumference of the heat transfer tube (3) through which the fluid to be heated passes, as shown in FIGS. 8 to 9. There is known a structure in which the heat transfer promoting fin (10) is attached via a spacer (13). (See Japanese Utility Model Publication No. 53-43921).

However, in the above-mentioned fin for promoting heat transfer, the surface where the heat transfer tube and the fin face each other (the surface of the fin) is smooth with respect to the flow direction of the heating fluid. Since the contact area between the fluid and the heat transfer tube is small, a sufficient heat transfer effect cannot be obtained.

[Problems to be solved by the device]

In this invention, a protrusion (rib rib processing) is provided on the surface of the heat transfer promoting fin described above, and when the heating fluid passes through the surface of the heat transfer tube, the flow of the heating fluid is regulated by the protrusion, The purpose of this is to prevent the sheet path of No. 2 and to increase the heat transfer efficiency by increasing the contact area with the heat transfer tube.

[Means for Solving the Problems]

That is, according to the present invention, a heat transfer tube that heats a fluid flowing inside by a heating fluid flowing on the outer surface and a substantially V-shaped heat transfer tube that is attached so as to face a valley on the outer surface of the heat transfer tubes of an adjacent set. It is characterized in that it is formed by combining with a heat promotion fin, and a required number of mountain-shaped projections are formed on the surface of the heat transfer promotion fin on the side of the water pipe.

[Action]

According to the above-mentioned structure, the heating fluid flows along the protrusion shape of the surface of the fin for promoting heat transfer, which is attached to the valley of the outer surface of the adjacent heat transfer tubes, and exchanges heat with the heat transfer tubes to form an annular smoke. It passes through the road and is discharged to the outside from the chimney.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1 to 5 show an example of a multi-tube type once-through boiler embodying the present invention. In FIG. 1, (1) is the upper head,
(2) is a lower head, both of which are annular. The upper and lower tubes (1) and (2) are connected by a large number of heat transfer tubes (3), but a gap (4) is set between adjacent heat transfer tubes (3) [about 1 m / m. ]
An annular heat transfer tube wall is formed along the upper and lower guides (1) and (2).

A boiler outer wall (5) is provided outside the heat transfer tube wall with a space therebetween, and an annular flue (6) is formed between the outer wall (5) and the heat transfer tube (3). A combustion device (7) is provided inside the upper header (1), and a combustion chamber (8) is formed below the combustion device (7).

Both ends (9) of each heat transfer tube (3) are reduced in diameter, and are fitted and welded to the upper pipe header (1) and the lower pipe header (2) respectively. Also, with the reduced diameter portion of each heat transfer tube (3),
The lower surface portion (81) of the combustion chamber (8) is protected by a partition wall (11) made of a heat resistant material.

The heat transfer accelerating fin (10) is, as shown in FIGS.
A large number of chevron-shaped protrusions (12) (ribbed) are formed at appropriate intervals on the outer side of the substantially V shape, and the portion facing the flue (6) side of the heat transfer tube (3) Protrusions (12) are attached in the valleys so as to be in contact with the outer surface of the heat transfer tube (3) as shown in FIGS.

In the above-mentioned structure, the operation will be described. The heating fluid (combustion gas) generated in the combustion chamber (8) first exchanges heat with the heat transfer tube (3) by radiant heat transfer to the heat transfer tube (3). Flow at a substantially right angle (see FIG. 3) and pass through the gap (4) formed by the adjacent heat transfer tubes (3) while exchanging heat by convective heat transfer. The chimney (6) provided in a part of the annular flue (6) passes through the gap (4 ') formed between the heat transfer promoting fin (10) and the heat transfer tube (3) while exchanging heat. (Not shown) is discharged into the atmosphere at a low temperature.

FIG. 6 shows that the projection shape of the above-mentioned embodiment is additionally processed in the axial direction of the heat transfer tube (3) to increase the contact area between the heating fluid and the heat transfer tube (3) to improve the heat transfer efficiency. It shows another embodiment. In this case, the projection height in the axial direction is lower than the initial projection height of the mountain.

FIG. 7 shows an embodiment in which the heat transfer tubes (3) are arranged in plural.

8 to 9 show a conventional embodiment, in which a spacer (13) for securing a gap between the heat transfer tube (3) and the heat transfer accelerating fin (10) is attached.

[Effect of device]

As described above, this invention has the following practical effects because the projections (rib rib processing) are formed on the surface of the fin for promoting heat transfer.

(1) Since the length of contact of the heating fluid with the heat transfer tube is increased, the heat transfer performance can be improved.

(2) Since the fins having the chevron shape are attached to the fins for promoting heat transfer, the flow of the heating fluid can be restricted to prevent the short pass.

(3) Since the protrusion has a simple curved surface, high performance can be obtained with low pressure loss.

(4) In the conventional fins for promoting heat transfer, a large number of spacers are required to secure a gap with the heat transfer tube. However, in this invention, the protruding surface serves as a spacer, which is not necessary.

(5) The protrusions (rib forming process) can be pressed similarly to the V-shaped process of the heat transfer accelerating fins, and are therefore inexpensive.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a multi-tube type once-through boiler showing an embodiment of the present invention, and FIG. 2 is a horizontal sectional view showing an arrangement of heat transfer tubes.
FIG. 3 is an enlarged cross-sectional view showing details of a mounting portion of the heat transfer promotion fin, and FIG. 4 is a perspective view showing a projection shape of the heat transfer promotion fin.
FIG. 5 is a perspective view showing a mounting portion of the heat transfer tube and the heat transfer accelerating fin, FIG. 6 is a perspective view showing another projection shape different from the projection shape of FIG. 4, and FIG. FIG. 8 is an enlarged cross-sectional view showing details of the heat transfer accelerating fins attached to the heat pipe, FIG. 8 is a perspective view showing the shape of the conventional heat transfer accelerating fins, and FIG. 9 is a detail of a mounting portion of the conventional heat transfer accelerating fins. FIG. (3) …… Heat transfer tube, (10) …… Heat transfer acceleration fin

Claims (1)

[Scope of utility model registration request] 1. A heat transfer tube (3) for heating a fluid flowing inside by a heating fluid flowing on an outer surface and a heat transfer tube (3) of an adjacent set, which are mounted so as to face each other in a valley of the outer surface.
Combining with a V-shaped heat transfer promotion fin (10),
A heat transfer promotion fin for a boiler, wherein a required number of mountain-shaped projections are formed on a surface of the heat transfer promotion fin (10) on the water pipe side.