JPS6038587A - Heat exchanger - Google Patents

Abstract

PURPOSE:To reduce the heat stress at the operation condition of the heat exchanger hitherto by a method wherein the temperature following capability of the whole manifold is improved by extending the under part of an inner pipe of a center pipe down to the vicinity of the lowest part of the manifold. CONSTITUTION:The lower part of the inner pipe of a center pipe is extended down to the vicinity of the lowest part of a manifold 7, and a hole 28 is bored at the top of a hemisphere part at the lower end of the manifold. Secondary fluid, which runs through heat transmitting pipes and flows in the manifold 7 from risers 5, and secondary fluid, which runs through in gaps 12 between an outer pipe 6 of the center pipe and the inner pipe 8 of the center pipe, flows down being guided to the elongated part of the inner pipe 8 of the center pipe, as shown with arrow lines in the figure, and returns at the lowest part of the manifold and flows in and runs upward the inner pipe 8 of the center pipe through the hole 28.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat exchanger, particularly a heat exchanger suitable for heat exchange of high temperature gas close to 1000°C.

The applicant previously filed a patent application for the heat exchanger shown in FIG. In Figure 1, the low-temperature secondary fluid enters the secondary fluid inlet chamber (2) from the inlet nozzle (1) as shown by the white arrow, and most of the fluid enters the secondary fluid inlet chamber (2) connected to the tube plate (3). heat tube (
4) In the process of descending inside the heat exchanger tube (4), it exchanges heat with the high temperature primary fluid flowing outside the tube, gradually increasing the temperature, passing through the inside of the riser (5) and then passing through the center pipe outer tube (6). ) into the lower manifold (7).

Also, a part of the secondary fluid in the secondary fluid inlet chamber (2) descends within the gap a between the outer center pipe (6) and the inner center pipe (8) and enters the manifold (7). Inflow. The secondary fluid that entered the manifold (7) flows through the center pipe inner tube (
8) flows into it from the open lower end, rises inside and flows out from the outlet nozzle (91).On the other hand, the high temperature primary fluid flows from the inlet nozzle (IO5 to the primary fluid inlet) as shown by the black arrow. Flows into the chamber aυ, most of which flows into the heat transfer tube (4)
It flows into the gap (+3) between the heat transfer tube (4) and the guide tube U from the open lower end of the guide tube (18), which surrounds the periphery of the guide tube (18) and whose upper end is connected to the tube plate (19). In the process of rising, the fluid exchanges heat with the secondary fluid flowing in the heat transfer tube (4), gradually lowering its temperature, and enters the primary fluid outlet chamber (I4).

In addition, a part of the primary fluid that has flowed into the primary fluid inlet chamber αυ is transferred to the storage pipe Q disposed around the outer center pipe (6).
The fluid flows from the open lower end of 51 into the gap (also I) between the outer pipe (15) and the center pipe outer tube (6), rises within this gap (16), and flows into the primary fluid outlet chamber (14). ) from which it flows out through the outlet nozzle αη. Container body (
Cooling material flows into the cooling chamber (23) from the inlet nozzle (c) as shown by the solid line arrow, and the coolant flows into the cooling chamber (22) formed between the In the process of descending, the container body (20) and the inner body (2I) are cooled and flowed out from the outlet nozzle (5). !■ is the insulation material attached to the outer surface of the manifold)'('/), 126
) is the inner body C! This is a heat insulating material attached to the inner surface of υ.

The above heat exchanger has excellent heat elongation absorption and heat transfer performance, but the secondary fluid flowing into the manifold (7) from the riser (5) becomes a rising hole and connects the bottom riser (5). Most of the secondary fluid remains in the portion of the manifold (7) below this position. Therefore, in the steady operation state of this heat exchanger, the temperature of the manifold (7i) is almost equal to that of the secondary fluid in the manifold (7) over the entire heat exchanger, so thermal stress does not occur, but during transients such as the start of operation, Although the temperature at the lower part of the manifold α1) does not rise rapidly in this state, the temperature at the upper part of the center give outer pipe (6) where it is attached to the upper layer plate (11) has good temperature tracking, so the temperature at the bottom of the center pipe pipe (6)
There was a problem that the thermal stress was reduced.

The present invention has been proposed in order to solve the above-mentioned problems.The present invention provides a heat exchanger in which the inner pipe of the center pipe is disposed in the outer pipe of the center pipe, and the inner pipe of the center pipe flows upward from the lower end of the inner pipe of the center pipe. A heat exchanger characterized in that a lower part extends downward to near the lowest part of a manifold.

In the present invention, since the above structure is provided, the secondary fluid does not accumulate in the manifold, and therefore, thermal stress during transient operation of the heat exchanger can be reduced.

The present invention will be described below with reference to one embodiment not shown in FIG. As shown in Figure 2, the center pipe inner tube (8)
It is structurally different from the one in Fig. 1 in that the lower part of the manifold (7) is extended downward to near the bottom of the manifold (7), and a hole/2 holes are bored at the apex of the hemispherical part at the lower end, but the rest is the same. It is.

The secondary fluid that has passed through the heat transfer tube (4) and entered the manifold (7) from the riser (5) and the center pipe outer tube (
6) and the center pipe inner tube (8), the secondary fluid that has flowed through the gap a is guided by the extension of the center pipe inner tube (8) and descends, as shown by the arrow in the figure. Manifold (7)
At the bottom of the center pipe, turn it over and pass through the hole (c) to insert the center pipe inner tube (
8) Go inside and rise. As shown in FIG. 6, a spirally protruding fin ridge is provided on the outer surface of the extension of the center pipe inner tube (8), and the manifold (7) and the center pipe inner tube (8) are provided with a spirally projecting fin.
) may be increased to further promote heat transfer to the inner surface of the manifold (7).

(Thus, the secondary fluid is guided to the lower end extension of the center pipe inner tube (8) and reaches the lowest part of the manifold (7).
Since there is no stagnation part for the next fluid and the temperature followability of the entire manifold (7) is improved, thermal stress in the transient state of continuous operation of the heat exchanger can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a heat exchanger that has already been proposed, Fig. 2 is a sectional view of a main part showing one embodiment of the present invention, and Fig. 3 is a perspective view of a main part showing another embodiment of the invention. be. Center pipe outer pipe...(6), center pipe inner pipe...
・(8), Maniho/I/)′″...(7) Sub-agent Patent attorney Shigefumi Okamoto and 6 others @Figure 1fON'/Figure 2, Ward 3

Claims (1)

[Claims] In the heat exchanger, the secondary fluid flowing into the manifold at the lower end of the outer center pipe flows into the manifold from the lower end of the inner center pipe disposed inside the outer center pipe and rises. A heat exchanger characterized in that the lower part of the tube extends downward to near the lowest part of the manifold.