JPH09229583A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent large stress from being applied to a fixed part between the circumference of a pipe plate and a casing, and further prevent force to pull out a heat transfer pipe from an end of the same from being applied to the pipe plate even when the casing presents greater thermal expansion. SOLUTION: A casing 1 includes a high temperature gas flow inlet 2 on one side and a high temperature gas flow outlet 4 on the other side through the inside of which easing high temperature gas 11 flows. A low temperature fluid flow inlet 8 and a low temperature fluid flow outlet 10 are provided in the casing 1 in the direction intersecting the direction where the high temperature gas flow inlet 2 and the high temperature gas flow outlet 4, and pipe plates 13, 14 are provided interiorly of the low temperature fluid flow inlet 8 and the low temperature fluid flow outlet 10, respectively. A plurality of heat transfer pipes 15 through the inside of which a low temperature fluid 12 flows are provided between both pipe plates 13, 14, and an expandable bent part 20 is provided at a location displaced inwardly of the casing 1 from the pipe plate 14 in the low temperature fluid flow outlet 10, whereby greater thermal expansion of the casing 1 is absorbed by the bent part 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger for heating a low temperature fluid with a high temperature gas.

[0002]

2. Description of the Related Art FIG. 3 is a side view showing an example of a heat exchanger provided in a boiler. A hot gas inflow duct 3 is connected to an upper end of a casing 1 through a hot gas inlet 2.
A hot gas outflow duct 5 is connected to the lower end of the casing 1 via a hot gas outlet 4.

Inside the casing 1, a plurality of heat exchangers 6 and 6, which will be described in detail later, are provided vertically, and the high temperature gas inflow port 2 is provided so as to communicate with these heat exchangers 6 and 6.
And a low temperature fluid inflow duct 8 connected to the low temperature fluid inflow duct 7 is formed on one side in a direction intersecting the direction in which the high temperature gas outflow port 4 is provided, and a low temperature fluid outflow duct 9 is formed on the other side of the casing 1. A connected cryogenic fluid outlet 10 is formed. In the figure, 11 indicates a high temperature gas led from a boiler, and 12 indicates a low temperature fluid such as air.

FIG. 4 is a vertical sectional side view showing an example of a conventional heat exchanger 6, in which a tube sheet 1 is provided in a low temperature fluid inlet 8 and a low temperature fluid outlet 10 formed on both left and right sides of a casing 1.
A plurality of heat transfer tubes 15 are fixed so that 3 and 14 are opposed to each other, and end portions thereof are penetrated and fixed to the tube sheets 13 and 14.
Are arranged side by side in the casing 1.

The heat transfer tube 15 is supported by a supporting member 16 provided in the vertical direction.
A lower end of the low temperature fluid outlet 10 is supported on a fixing member 17 provided in the casing 1 so as to be horizontally slidable via a slide portion 18, and a lower surface of the low temperature fluid outlet 10 is provided outside the casing 1. Slide part 1 on 17
It is supported by 8 so as to be slidable in the horizontal direction.

Further, the lower surface of the low-temperature low-temperature fluid inlet 8 is fixed by a fixing point 19, so that the thermal expansion of the casing 1 can be moved leftward in FIG. Has become.

A high temperature gas 11 such as combustion gas flowing in from the high temperature gas inflow duct 3 shown in FIG. 3 flows from the high temperature gas inlet 2 shown in FIG. To the hot gas outflow duct 5 of FIG.

A low temperature fluid 12, such as air, flowing in from the low temperature fluid inflow duct 7 of FIG. 3 exchanges heat with the outer high temperature gas 11 while flowing from the low temperature fluid inlet 8 into the heat transfer tube 15 shown in FIG. 3 and is heated through the cryogenic fluid outlet 10.
Out into the low temperature fluid outflow duct 9.

[0009]

Since a high temperature gas 11 such as a combustion gas flows inside the casing 1, due to thermal expansion, the temperature is lower than that of the tube plate 13 on the side of the low temperature fluid inlet 8 fixed at the fixed point 19. The tube sheet 14 on the fluid outlet 10 side is displaced in the direction of separation (leftward in FIG. 4), and the casing 1 has a high temperature on the high temperature gas inlet 2 side.
Since the temperature on the side of the hot gas outlet 4 is low, the tube sheet 14 receives the displacement S in the inclined direction as shown by the broken line in FIG.

On the other hand, the outer side of the heat transfer tube 15 is also exposed to the high temperature gas 11. However, since the low temperature fluid 12 flows through the heat transfer tube 15, the temperature rise is smaller than that of the casing 1.
The thermal expansion is also smaller than that of the casing 1.

Due to the difference in extension between the casing 1 and the heat transfer tube 15, a large stress acts on the fixed portion between the tube sheet 14 and the casing 1, or the heat transfer tube 1 is attached to the tube sheets 13 and 14.
There is a problem that a force in the direction of pulling out 5 acts, causing leakage of the high temperature gas 11 and the low temperature fluid 12.

The present invention solves such a problem, and even if the casing undergoes a large thermal expansion, a large stress does not act on the fixed portion between the periphery of the tube sheet and the casing, and the heat transfer tube is pulled out from the tube sheet. It is an object of the present invention to provide a heat exchanger in which the force of 1 is not applied.

[0013]

A heat exchanger according to the present invention is provided with a hot gas inlet on one side and a hot gas outlet on the other side, and a casing through which hot gas flows, wherein the hot gas inlet is provided. A low temperature fluid inlet and a low temperature fluid outlet are provided in a direction intersecting the direction in which the high temperature gas outlet and the high temperature gas outlet are provided, and a tube plate is provided inside each of the low temperature fluid inlet and the low temperature fluid outlet, and both tubes are provided. A plurality of heat transfer tubes in which a low temperature fluid flows inside the plates are arranged side by side, and a bendable portion is provided at a position biased inward of the casing from the tube plate of the low temperature fluid outlet, The bent portion expands and contracts to absorb the thermal expansion of the casing, and the tube plate is no longer subjected to the force in the direction of pulling out the heat transfer tube.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical sectional side view of an embodiment of the present invention, in which the same parts as those in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted.

As in the conventional case, the tube plates 13 and 14 are provided on the left and right sides inside the casing 1 so that their peripheries are fixed to the low temperature fluid inlet 8 and the low temperature fluid outlet 10 integrated with the casing 1 and face each other. A plurality of heat transfer tubes 15 having end portions penetrating the tube sheets 13 and 14 and fixed thereto are arranged in parallel in the casing 1.

The tube sheet 14 at the cryogenic fluid outlet 10.
An expandable and contractable bent portion 20 is formed at a position closer to the casing 1 so as to be bent and protruded outward.

As shown in FIG. 2, the bent portion 20 is formed so as to extend over the entire circumference of the low temperature fluid outlet 10.

Next, the operation will be described.

Inside the casing 1, a hot gas inlet 2 is provided.
A high-temperature gas 11 such as combustion gas flows in from this, and a large thermal expansion occurs in the casing 1, but the temperature of the heat transfer tube 15 is low at this time, so the thermal expansion of the heat transfer tube 15 is smaller than that of the casing 1.

At this time, since the bent portion 20 formed in the casing 1 can freely expand and contract, a large thermal expansion of the casing 1 is absorbed, and the displacement due to the expansion and contraction of the casing 1 is not transmitted to the tube sheet 14.

Therefore, a large stress does not act on the portion where the periphery of the tube sheet 14 is conventionally fixed to the casing 1, and the force in the direction of pulling out the heat transfer tube 15 does not act on the tube sheets 13 and 14, either.

The bent portion 20 is connected to the low temperature fluid outlet 10.
The temperature is higher on the low temperature fluid outlet 10 side than on the low temperature fluid inlet 8 side, and the low temperature fluid outlet duct 9
This is because the thermal expansion of the low temperature fluid outflow duct 9 can be absorbed at the same time.

[0024]

According to the present invention, the expandable / contractible bent portion absorbs a large thermal expansion of the casing, a large stress does not act on the fixed portion between the periphery of the tube sheet and the casing, and the tube sheet also has the end of the heat transfer tube. There is an effect that the force in the direction of pulling out the portion does not act and leakage of high temperature gas and low temperature fluid does not occur.

[Brief description of drawings]

FIG. 1 is a vertical side view of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a side view showing an example of a heat exchanger provided in a blast furnace.

FIG. 4 is a vertical sectional side view showing an example of a conventional heat exchanger.

[Explanation of symbols]

 1 Casing 2 High Temperature Gas Inlet 4 High Temperature Gas Outlet 6 Heat Exchanger 8 Low Temperature Fluid Inlet 10 Low Temperature Fluid Outlet 11 High Temperature Gas 12 Low Temperature Fluid 13 Tube Sheet 14 Tube Sheet 15 Heat Transfer Tube 20 Bent Section

Claims (1)

[Claims] 1. A casing in which a hot gas inlet is provided on one side and a hot gas outlet is provided on the other side, through which the hot gas flows, intersecting a direction in which the hot gas inlet and the hot gas outlet are provided. A cryogenic fluid inlet and a cryogenic fluid outlet are provided in a direction in which each of the cryogenic fluid inlet and the cryogenic fluid outlet is provided with a tube plate, and a plurality of transmissions through which the cryogenic fluid flows between the tube sheets. A heat exchanger characterized in that heat tubes are arranged in parallel, and a bendable portion is provided at a position biased toward the inside of the casing from the tube plate of the low temperature fluid outlet.