JPS5831286A - Recovering device for heat of exhaust gas - Google Patents

Abstract

PURPOSE:To contrive to enhance heat transmission from an exhaust gas to a fluid, by a method wherein a filler having a high thermal conductivity is packed in a space constructed by a trunk tube and a heat-transmitting pipe. CONSTITUTION:A low-temperature fluid to be heated is introduced through an inflow port 16 provided for a shell 1. When the fluid is heated, the thermal energy of the exhaust gas is transmitted to the fluid through the trunk tube 9 and the heat-tranmitting pipe 8 making line contact with the tube 9. In this case, the filler 12 having a high thermal conductivity is packed in the space 10 formed by the outside peripheral surface of the tube 9 and the pipe 8 to increase the heat-transmitting surface area between the tube 9 and the pipe 8, so the thermal energy transmitted to the tube 9 can be transmitted efficiently to the fluid in the pipe 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for recovering heat energy contained in exhaust gas.

Conventionally, as a device to recover the thermal energy of high-temperature exhaust gas discharged from an internal combustion engine such as a diesel engine, a heat transfer tube of a predetermined length is provided inside a cylindrical shell, and the exhaust gas is introduced into the shell. There is a system in which the heat exchanger tube is brought into direct contact with the surface of the heat exchanger tube, and a low-temperature fluid is caused to flow inside the heat exchanger tube, so that the thermal energy of the exhaust gas is recovered by heat exchange between the low-temperature fluid and the exhaust gas.

By the way, as mentioned above, when the exhaust gas is brought into direct contact with the surface of the heat exchanger tube, the heat absorption rate from the exhaust gas is good, but the sulfur dioxide gas and water vapor contained in the exhaust gas are absorbed by the surface of the heat exchanger tube. Condensation forms and produces sulfuric acid, which corrodes the heat transfer tubes and creates holes. Therefore, in order to prevent accidents such as fluid leakage into the cylinder of an internal combustion engine due to sulfuric acid corrosion holes in heat transfer tubes, it is necessary to frequently inspect and replace heat transfer tubes early. There was a problem.

In addition, in the conventional exhaust gas heat recovery device, the low temperature fluid introduced into the heat exchanger tube is always caused to flow through a flow path of a predetermined length to increase its temperature. Therefore, if the temperature of the low-temperature fluid supplied to the heat recovery device or the air temperature around the heat recovery device changes depending on usage conditions such as cold or hot weather, the temperature of the low-temperature fluid coming out of the heat recovery device will change accordingly. There was a problem with this.

This invention was made in consideration of the above-mentioned circumstances. 1) Heat is recovered by unitizing the part that performs heat exchange between exhaust gas and low-temperature fluid, and increasing or decreasing the number of units depending on usage conditions such as cold or hot climate. The amount can be increased or decreased,■
In addition, in this unit, the heat exchanger tube through which the low-temperature fluid passes is wrapped around the outside of the body tube through which exhaust gas passes, thereby preventing corrosion and pitting of the heat exchanger tube. An object of the present invention is to provide an exhaust gas heat recovery device that improves heat transfer from the exhaust gas to a fluid by filling a space with a filler material having good thermal conductivity.

The present invention will be described below based on embodiments shown in the drawings.

Figures 1 and 2 show an embodiment of the present invention. Figure 2 shows a heat exchange unit, and Figure 1 shows an example of a device that combines these units. It is a shell that houses the whole thing. This shell 1 is formed into a cylindrical shape as a whole by connecting exhaust pipe connecting cylinders 3 and 4 to both ends (upper and lower ends in FIG. 1) of a heat exchange unit storage cylinder 2. Exhaust pipes 5,
Flanges 3a and 4a are provided for connection with 6. The tubes 2, 3.4 are connected by bolting the respective flanges 2a, 3b, 4b which are in contact with each other, and are designed so that they can be separated from each other when necessary.

Inside the heat exchange unit storage tube 2, a plurality of (two in the figure) heat exchange units 7 are arranged in parallel.

In the heat exchange unit 7, a heat transfer tube 8, which serves as a flow path for a low-temperature fluid that undergoes heat exchange with exhaust gas, is spirally wound around the outer peripheral surface of a barrel tube 9, which serves as a flow path for exhaust gas. A space 10 formed by the outer circumferential surface of the heat exchanger tube 8 and the outer circumferential surface of the barrel tube 9 is sealed by a jacket 11 that covers the outer circumference of the heat exchanger tube 8 wound in a spiral manner. This sealed space 10 is filled with a filler 12 made of a material with good thermal conductivity, such as aluminum particles. The jacket 11 is provided to prevent the filler 12 from falling off or flowing out due to the influence of surrounding vibrations or heat, and is designed to prevent the filler 12 from falling off or flowing out due to the influence of surrounding vibrations or heat.
It may be omitted if . Furthermore, fins 13 are provided on the inner circumferential surface of the barrel tube 9 along the axial direction of the barrel tube 9 to increase the amount of heat absorbed from the exhaust gas.

The plurality of heat exchange units 7 configured as described above are
7 langes 9a formed at the upper and lower ends of each barrel tube 9;
9b is the exhaust branch 7 flange 1 using a tightening tool such as a bolt.
4.15, each barrel 9
are connected in parallel.

The exhaust branching 7 langes 14, 15Fi have a function of communicating the exhaust gas flow path of the heat exchange unit 7 with the exhaust gas flow path of the shell 1, and allow these heat exchange units 7 to be detachably attached to the shell 1. It also has a function as a mounting bracket for mounting. That is, both flanges 14
．． Exhaust flow ports 14a and 15a each having a diameter equal to the inner diameter of the body tube 9 are provided in the portions of the body tube 9 that the flanges 9a and 9b of the body tube 9 abut, respectively. 14 has a diameter approximately equal to the inner diameter of the heat exchange unit housing cylinder 2 of the shell 1, and the other exhaust branching 7 tunnel 15 has a diameter larger than the inner diameter of the heat exchange unit housing cylinder 2. 7 for exhaust branch
Lunge 15 exchanges heat with shell 1! By being held by the respective flanges 2g and 4b of the knit storage tube 2 and the exhaust pipe connection tube 4, the exhaust pipe branching flange 14
．． Each of the heat exchange units 7 fixed to the shell 1 is fixed to the shell 1, and the barrel tube 9 of each heat exchange unit 7 is configured to communicate with the exhaust pipe connecting tubes 3 and 4 of the shell 1. has been done.

Further, the heat exchanger tubes 8 of each heat exchange unit 7 arranged in the shell 1 are connected to the outlet 8a of one heat exchange unit 7.
is connected to the inlet 8b of the other heat exchange unit 7, and the inlet 8b of one unit 7 is connected to the inlet 16 provided in the heat exchange unit housing cylinder 2, and the outlet 8a of the other unit 7 is connected to the inlet 8b of the other unit 7. is connected to the outlet 17 provided in the heat exchange unit housing cylinder 2, and the inlet 16 is connected to the outlet 17 provided in the heat exchange unit storage cylinder 2.
7 to form a series of flow paths.

In the heat recovery device configured as described above, exhaust gas is introduced from the exhaust pipe 6 on the internal combustion engine side to the lower part of the exhaust pipe connecting tube 4 as shown by the arrow (A) in FIG. Mf is transferred into the cylinder 9 of each heat exchange unit 7 by the branching flang 15, and is sent from above the cylinder 9 to the exhaust pipe 5 on the atmosphere side as shown by the arrow (b), thereby raising the temperature. As shown by the arrow (C) in FIG. While being led through the trench, it receives thermal energy from the exhaust gas and is heated, and the heated fluid flows from the outlet 17 as shown by the arrow)
It is supplied to the specified equipment as follows. When the temperature of the low-temperature fluid is raised, the thermal energy of the exhaust gas is transferred from the cylinder 9 to the cylinder 9.
The heat is transferred to the low-temperature fluid via the heat transfer v8 which is in line contact with the tube, and the space 10 formed by the outer circumferential surface of the cylinder 9 and the heat transfer tube 8 is filled with a filler 12 with good thermal conductivity. is filled and the heat transfer area between the body tube 9 and the heat transfer v8 is increased, so that the thermal energy transferred to the body tube 9 can be efficiently transferred to the low temperature fluid in the heat transfer Y8. .

In addition, the heat exchanger tubes 8 are wound around the outer periphery of the body cylinder 9, which serves as a flow path for exhaust gas, and the exhaust gas does not come into direct contact with the heat exchanger tubes 8. Therefore, as mentioned above, holes are formed in the heat exchanger tubes 8 due to sulfuric acid corrosion. There will be no more space. Therefore, it is not necessary to carry out inspection work as frequently as in the conventional case to prevent accidents caused by corrosion holes in the heat exchanger tubes 8, and the life of the heat exchanger tubes 8 can be significantly extended.

Further, since the heat exchange section is composed of a plurality of heat exchange units 7, and each heat exchange unit 7 is detachably attached to the shell 1 via a fastener such as a bolt, The heat exchange unit 7 can be easily attached to and detached from the shell 1 by operating fasteners such as bolts, and is compatible with the conditions under which the exhaust gas heat recovery device of the present invention is used, such as cold and hot climate. By increasing or decreasing the number of heat exchange units 7 in the shell 1 accordingly and increasing or decreasing the amount of recovered heat, various effects such as being able to raise the temperature of the low-temperature fluid to a desired temperature and supply it to a required location are produced. .

[Brief explanation of the drawing]

1 and 2 show one embodiment of the present invention, with FIG. 1 being a partially sectional explanatory view of the whole, and FIG. 2 being a sectional view of the main part of FIG. 1. DESCRIPTION OF SYMBOLS 1... Shell, 7... Heat exchange unit, 8... Heat transfer officer, 9... Cylinder, 10... Space, 12... Filler.

Claims (1)

[Claims] A heat transfer tube, which serves as a flow path for low-vortex fluid, is spirally wound around the outer circumferential surface of the cylinder, which serves as a flow path for exhaust gas, and heat is transferred to the space formed by the outer circumferential surface of the heat transfer tube and the outer circumferential surface of the cylinder. Equipped with a heat exchange unit filled with a highly conductive filler and a cylindrical shell in which multiple heat exchange units are attached and detached, the exhaust gas introduced into the shell is installed inside the shell. A heat recovery device for exhaust gas that efficiently recovers hot strips from exhaust gas by passing a low-temperature fluid through the cylinders of each heat exchange unit and through the heat transfer tubes of the heat exchange units.