JPS6321112B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat exchanger that transfers heat between a medium flowing in a heat transfer tube and a heat transfer tube, and more specifically relates to a dust collection structure of the heat exchanger. This is related to.

Among the heat exchangers, there is a combustion exhaust gas heat exchanger and the like that release the heat of a medium flowing inside the heat exchanger tube to the outside of the heat exchanger tube.

Since combustion gas from boilers and the like still has sufficient thermal energy, heat is recovered through a heat exchanger. In this case, if a heat exchanger with high heat exchange efficiency is used, the heat exchanger can be made smaller, lighter, and lower in cost.

Conventionally, various measures such as high-performance heat transfer surfaces have been used to improve heat exchange efficiency, but foreign matter such as dust present in the exhaust gas adheres to the heat transfer surfaces and reduces the heat transfer coefficient. It was becoming. For this reason,
Although it is necessary to provide a means to remove foreign matter from the exhaust gas, there has been no effective means for this purpose.

On the other hand, conventional exhaust gas heat exchangers utilize convection heat transfer and heat conduction, and do not utilize radiant heat. For this reason, it has become impossible to expect an improvement in the heat transfer coefficient.

An object of the present invention is to provide a dust collection device that prevents dust in a medium from adhering to the inner surface of a heat transfer tube and also performs radiant heat transfer to improve heat exchange efficiency. .

The present invention is characterized in that fins such as cross fins are provided in the heat transfer tube, and a voltage is applied to the fins to cause dust in the exhaust gas to be adsorbed to the fins, and the fins are heated to the temperature of the exhaust gas. The radiant heat from the outside surface heats the inside of the heat transfer tube to improve heat transfer.

This will be explained in detail below using figures.

First, FIG. 1 is a sectional view illustrating an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG.

A cross-shaped fin 2 is provided inside the heat exchanger tube 1. A heat recovery medium such as exhaust gas is flowing inside the heat transfer tube. The heat exchanger tube 1 is connected with the fin 2 as an anode so that an electric field is formed between the heat exchanger tube 1 and the fins 2.
is electrically connected to the cathode. It is desirable that the same number of protruding electrodes 3 as the number of fins 2 are provided on the inner surface of the heat exchanger tube 1, and that the protruding electrodes 3 are arranged at intermediate positions between the fins. The polarity of the protruding electrode 3 is the same as that of the heat exchanger tube 1, which is a cathode. Note that the polarity of the electrodes may be reversed depending on the dust components in the exhaust gas.

The fins 2 may be spirally twisted in the longitudinal direction. Further, the protruding electrodes 3 may be protruding electrodes extending in the longitudinal direction, or may be protruding electrodes arranged in a large number in a row.

An embodiment of the present invention configured as described above will be described.

When the exhaust gas flows like P, the heat of the exhaust gas is given to the fins 2 and the heat exchanger tubes 1. A medium to be heated, such as water or Freon, is present outside the heat exchanger tube 1, and the heat in the exhaust gas is recovered to water, Freon, or the like.

In the present invention, the fins 2 reach a high temperature and give radiant heat to the heat transfer tube 1 as indicated by Q.

Therefore, the heat recovery effect becomes even higher. Even if foreign matter in the exhaust gas does not adhere to the inside of the heat exchanger tube 1, it will all adhere to the fins 2 due to the action of the electric field. Therefore, there is no foreign matter adhering to the inner surface of the heat exchanger tube 1, and the amount of heat applied to the heat exchanger tube 1 and conducted to the outer surface of the heat exchanger tube 1 does not decrease.

Also, whether the foreign matter S attached to the fins 2 reduces the amount of heat radiated from the fins 2 is because radiant heat is determined by absolute temperature, so the radiant heat due to the temperature of the foreign matter S attached to the fins is given to the heat transfer tube 1. , there is no particular decrease in radiant heat.

As described above, according to the present invention, since the fins 2 are used as dust collectors and radiant heat sources, the heat exchange efficiency of the heat exchanger tubes 1 is significantly improved. In addition, since the protruding electrode is provided on the inner surface of the tube, the discharge into the medium made of gas flowing through the gap between the protruding electrode and the fin is effectively carried out, and the dust is reliably charged. It becomes easy to adhere to the fins.

In addition, in the above embodiment, the heat exchanger tube 1 is not necessarily limited to a circular tube.

Further, the fins 2 may also have a shape other than a cross, as long as they have a linear shape or a plurality of blades, such as three blades, extending radially from the center of the heat exchanger tube.

Further, the fins 2 include both straight and twisted fins, and those with twist provide more uniform radiant heat to the heat transfer tube.

Furthermore, the flowing fluid within the heat exchanger tube 1 is not limited to exhaust gas, but may be any non-conductive gas. It is clear that the medium outside the heat exchanger tube 1 is not limited to water or Freon either.

The present invention also includes a device for exchanging heat from a medium outside the heat exchanger tube to a medium inside the heat exchanger tube.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is a sectional view taken along the line AA in FIG. 1. 1: heat exchanger tube, 2: fin.

Claims (1)

[Claims] 1 Consisting of a heat exchanger tube through which a non-conductive medium made of gas flows, and a plurality of fins arranged in the tube and provided radially, the fins have a gap with the inner surface of the heat exchanger tube, and the fins have a gap with the inner surface of the heat exchanger tube, A heat exchanger in which protruding electrodes are provided on the inner surface of the tube to apply a potential difference between the fins and the heat transfer tube to reduce dust in the non-conductive medium and to perform radiant heat transfer by the fins.