JPS5812908A - Multitubular type once-through boiler - 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 multi-tubular once-through boiler.

Conventionally, the water tubes used in multi-tube once-through boilers are bare tubes, which have the disadvantage of having a small heat transfer area per unit volume and requiring a large installation space fQ.

Therefore, it is possible to use a water pipe with one fin, but a water pipe with fins in which the fins are attached in a circumferential direction or in a spiral shape has the disadvantage that the flow rate of the combustion gas through it is slow and a high heat transfer coefficient cannot be obtained.

In view of the above points, it is an object of the present invention to provide a multi-tubular once-through boiler that requires a small installation space and has good heat transfer.

Hereinafter, an embodiment of the present invention will be described based on the drawings. An upper header 1 and a lower header 2 are both formed in an annular shape. The upper and lower headers 1 and 2 are connected by a large number of vertical water pipes 3, and these water pipes 3 are arranged as an annular water pipe wall with a slight gap. A boiler outer wall 4 is provided on the outside of the water tube wall at a distance from this. In this way, a &Ill-shaped combustion gas passage 5 is formed between the water tube wall and the boiler outer wall 4. A combustion device 6 is provided inside the lower header 2. A partition wall 1 is provided above the inside of the water tube wall to horizontally partition the inside thereof, and a space below the partition wall 7 is formed into a combustion chamber 8, and a space above the partition wall 7 is formed into a flue 9.

Both ends of each water tube 3 are reduced-diameter portions 10, which are fitted and welded to the tube plates of the upper header, the sleeve 1, and the lower header 2, respectively. The fins 11 are attached to the length tt3 in a circumferential direction or in a spiral shape. It is preferable that the portions of the fins 11 that contact each other be bent, cut or cut to shorten the distance between the wood pipe and the water pipe, thereby increasing the flow rate of the combustion gas. Heat transfer promoting plates 12 having a substantially V-shaped cross section are attached to the valleys of the portions of the finned water pipes 3 facing the boiler outer wall 4 side, and there are a few heat transfer promoting plates 12 between the finned water pipes 3 and the finned water pipes 3. They are arranged so that there is a gap between them.

To explain its operation in the above configuration, the combustion gas generated in the combustion chamber 8 first exchanges heat with the finned water pipe 3 by radiation heat transfer, flows almost perpendicularly to one water pipe, and flows into the adjacent finned water pipe. It passes through the gap formed by 3°3 while exchanging heat by convection heat transfer, and then passes through the gap formed between it and the heat transfer promoting plate 12 while exchanging heat (passes through the annular combustion gas passage. 5. At this time, heat transfer is good due to the fins 11 and the heat transfer promoting plate 12. Then, the combustion gas passes through the gap between the water pipes and reaches the flue 9 provided inside the upper header 1. It is discharged to the outside from the chimney.

As explained above, this invention uses a finned water pipe,
Moreover, since it is configured with a heat transfer accelerator plate, it is possible to provide a multi-tubular once-through boiler that requires a small installation space and has good heat transfer.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing an embodiment of this invention.
1. FIG. 2 is a cross-sectional view, and FIG. 3 is a partially enlarged cross-sectional view. 1 is the upper header, 2 is the lower header, 3 is the wood pipe, 4 is the boiler outer wall, 5 is the combustion gas passage, 6 is the combustion device, 7 is the bulkhead,
8 is the combustion chamber, 90′i flue, 10 is the reduced diameter part of the water pipe, 11
12 is a heat transfer accelerator plate. Figure 1

Claims (1)

[Claims] Both the upper header 1 and the lower header 2 are formed in an annular shape, and the upper and lower headers 1 and 2 are connected by a number of vertical water pipes 3, and these water pipes 3 are arranged as an annular water pipe wall with a slight gap. The boiler outer wall 4 is installed at intervals on the outside of the water pipe wall.
An annular combustion and gas passage 5 is formed between the water tube wall and the boiler outer wall 4, a combustion device 6 is provided inside the lower header 2, and the inside is horizontally positioned above the water tube wall. A partition wall 7 is provided, and the space below the partition wall 7 is formed into a combustion chamber 8, and the space above it is formed into a flue 9. Fins 11 are attached to the water pipe 3 in a circumferential direction or in a spiral shape. ,
A multi-tubular once-through boiler characterized in that a heat transfer promoting plate 12 having a substantially V-shaped cross section is attached to the valley of the portion of the finned water tube 3 facing the boiler outer wall 4 side.