Heat exchanger

Abstract

A plurality of heat-exchange tubes 30 each including a flat pipe including a groove 36 and wavelike depression-and-projection portions 33, 34 are arranged in parallel in such a manner that each of respective longitudinal directions thereof is a vertical direction, and a heat exchange medium is made to flow from an inlet 31 at each lower portion to an outlet 32 at each upper portion. Guide walls 43, 44 are provided in a shell 40, and exhaust gas is made to flow an inlet 41 at an upper portion to an outlet 42 at a lower portion, thereby making the exhaust gas meander in flow paths 46a to 46d and a space between the plurality of heat-exchange tubes 30. The exhaust gas and the heat exchange medium have flows opposed to each other as a whole, and a secondary flow of the exhaust gas is made to occur by the wavelike depression-and-projection portions 33, 34, thereby enhancing the heat exchange efficiency, and the arrangement in such a manner that each of the longitudinal directions is the vertical direction and the formation of a groove 36 and the wavelike depression-and-projection portions 33, 34 enable acceleration of downward discharge of condensed water.

Description

TECHNICAL FIELD[0001]The present invention relates to a heat exchanger and specifically relates to a finless heat exchanger that recovers heat of exhaust gas, which results from combustion, via heat exchange with a heat exchange medium.BACKGROUND ART[0002]Conventionally, for this type of heat exchanger, one in which cooling water is made to flow in a plurality of tubes each formed into a U-shape and exhaust gas is made to flow substantially perpendicular to the cooling water in the plurality of tubes from the side of the plurality of tubes close to outlets for the cooling water, thereby recovering heat of the exhaust gas (see, for example, non-patent literature 1). In this heat exchanger, i.e., the plurality of tubes are formed using stainless steel to prevent corrosion caused by exhaust gas, and corrugated fins are inserted between the plurality of tubes to enhance the heat exchange efficiency.CITATION LISTNon Patent Literature[0003]Non Patent Literature 1: Transactions of the Japa...

AI Technical Summary

Benefits of technology

The patent is about a heat exchanger that recovers heat from exhaust gas. The main goal is to make the heat exchanger smaller and more efficient in exchanging heat with the exhaust gas. However, downsizing the heat exchanger can lead to lowered efficiency due to the presence of condensed water between the tubes, which hinders the flow of the exhaust gas. The invention aims to address this issue and achieve better heat exchange efficiency in the downsized heat exchanger.

Problems solved by technology

Although a heat exchanger is downsized by flattening the tubes and reducing the spaces between the tubes to enhance the efficiency of heat exchange with exhaust gas, if the spaces between the tubes are reduced, the condensed water remains between the tubes, hindering the flow of the exhaust gas, which results in a decrease in heat exchange efficiency.

In particular, in a heat exchanger with fins attached between the tubes, the fins hinder discharge of condensed water, resulting in a significant decrease in heat exchange efficiency in addition to a decrease in fin efficiency.

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