JP4332870B2

JP4332870B2 - Multi-tube heat exchanger

Info

Publication number: JP4332870B2
Application number: JP01191199A
Authority: JP
Inventors: 正佳臼井
Original assignee: Usui Co Ltd
Current assignee: Usui Co Ltd
Priority date: 1999-01-20
Filing date: 1999-01-20
Publication date: 2009-09-16
Anticipated expiration: 2019-01-20
Also published as: JP2000213877A

Description

【０００１】
【発明の属する技術分野】
本発明は、例えばＥＧＲガスの冷却に用いられる多管式の熱交換器に関するものである。
【０００２】
【従来の技術】
例えばエンジンの冷却液などによってＥＧＲガスを冷却する装置として利用される多管式の熱交換器は、図８、図９にその一例を示すごとく、両端部に冷却媒体流入口１−１および冷却媒体流出口１−２を設けた胴管１内部において、ストレート管の伝熱管２−１で構成された伝熱管群２の両端部が板金製のチューブシート３にろう付けにより固着配列され、該伝熱管群２の中間部はバッフルプレート５にて支持されており、一方、チューブシート３はその外周端部を胴管１にろう付けにより固着され、前記胴管１の一方の端部にはＥＧＲガスの流入口４−１が設けられた端部キャップ４が固着され、また他方の端部にはＥＧＲガスの流出口４−２が設けられた端部キャップ４が固着された構成となし、かつ前記端部キャップ４のガス流入口４−１およびガス流出口４−２の外側開口端部に締結用フランジ６が外嵌固着された構造となっているものが一般的である。
【０００３】
【発明が解決しようとする課題】
しかし、上記した従来の多管式熱交換器において、エンジンの冷却液などの冷却水を冷媒として用いてＥＧＲガスを冷却する場合、前記冷却水が胴管１内に充満している場合は問題ないが、例えばエンジンの冷却水量が何等かの原因により減少して胴管１内の水位が下がり胴管１の上側内周面近傍の伝熱管群２の一部が水面より露出して蒸気中に存在すると、その外表面の温度が当該伝熱管内を通過するＥＧＲガス温度まで上昇してしまい、その結果高い熱応力を生じてろう付け継手部より破壊するか、あるいはチューブシート３間で伝熱管が伸びて座屈や曲がりを生じてＥＧＲガス冷却装置の寿命を縮めてしまうという問題を生じ、また伝熱管の一部が水面より露出すると当該伝熱管はほとんど冷却されないため熱交換性能も低下するという問題を生じる。
【０００４】
本発明は上記した従来の多管式熱交換器の問題を解決するためになされたもので、何等かの原因で胴管内の冷却水の水位が下がり胴管の上側内周面近傍の伝熱管群の一部が水面より露出して外表面の温度が上昇しても、その熱が胴管内の冷却水中に放熱されるような手段をこうじることにより伝熱管の座屈や曲がりを防止し冷却装置の寿命を延ばすことができるとともに、熱交換性能の低下を防止し得る多管式熱交換器を提供しようとするものである。
【０００５】
【課題を解決するための手段】
本発明は上記課題を解決するため、両端部に冷却媒体流入口および冷却媒体流出口が設けられた胴管の内壁の両端部付近に固定されたチューブシートまたはハブに伝熱管群が固着配列され、かつ該伝熱管群はその中間部をバッフルプレートで支持され、さらに前記胴管の両端部には端部キャップが固着され、また前記端部キャップには高温流体の流入口と流出口が設けられ、前記端部キャップの高温流体流入口および流出口の外側開口端部に締結用フランジが外嵌固着された構造であって、ほぼ水平に配置される多管式熱交換器において、胴管の上側内周面近傍の伝熱管群の一部が水面より露出して外表面の温度が上昇した場合の伝熱面の熱を胴管内冷却媒体中に伝熱し得る手段を設けたもので、その第１の実施態様は胴管内の冷却媒体レベルが低下した場合に、少なくとも冷却媒体水面より露出する前記チューブシートの内壁面またはハブの内壁面またはバッフルプレートの外表面を、銅めっき層または銅クラッド層で被覆したことを特徴とし、第２の実施態様は胴管内の冷却媒体レベルが低下した場合に、少なくとも冷却媒体水面より露出する伝熱管を銅めっき層または銅クラッド層を有する管で構成したことを特徴とし、第３の実施態様は前記銅めっき層または銅クラッド層を有する管で構成した伝熱管を管軸方向に傾斜して配置したことを特徴とし、第４の実施態様は胴管内の冷却媒体レベルが低下した場合に、少なくとも冷却媒体水面より露出する前記伝熱管相互間または各伝熱管に、一部が冷却媒体中に浸漬するごとく板状または棒状の放熱部材を取付けたことを特徴とするものである。
【０００６】
本発明において、胴管内の冷却媒体レベルが低下した場合に、少なくとも冷却媒体水面より露出するチューブシートの内壁面またはハブの内壁面またはバッフルプレートの表面を、銅めっき層または銅クラッド層で被覆したのは、高温となった伝熱管の外表面の熱をチューブシートの内壁面またはハブの内壁面またはバッフルプレートの表面に形成した銅めっき層または銅クラッド層を介して冷却媒体中に放熱させるためである。また、少なくとも冷却媒体水面より露出する伝熱管を銅めっき層または銅クラッド層を有する管で構成したのは、高温となった伝熱管の外表面の熱を伝熱管の銅めっき層または銅クラッド層を介して冷却媒体中に放熱させるためである。さらに、少なくとも冷却媒体水面より露出する前記伝熱管相互間または各伝熱管に、一部が冷却媒体中に浸漬するごとく板状または棒状の放熱部材を取付けのは、高温となった伝熱管の外表面の熱を前記放熱部材を介して冷却媒体中に放熱させるためである。
【０００７】
すなわち、何等かの原因で胴管内の冷却媒体のレベルが、胴管の上側内壁付近の伝熱管が胴管内の冷却媒体のレベルより露出する位に下がった場合、冷却媒体レベルより露出した伝熱管は、当該管内を通流する高温流体の熱により管外表面温度が上昇するが、その熱はチューブシートの内壁面またはハブの内壁面またはバッフルプレートに設けた銅めっき層または銅クラッド層、または伝熱管自体に設けた銅めっき層または銅クラッド層、あるいは伝熱管に装着した板状または棒状の放熱部材により冷却媒体中に放熱されるので、伝熱管の管外表面温度が極端に上昇することがなくなり、熱応力が軽減されることにより伝熱管の伸びを抑制することができる。
【０００８】
なお、本発明において伝熱手段に銅めっき層または銅クラッド層を用いたのは、以下に示す理由による。
すなわち高温で使用される多管式熱交換器の構成部品はその耐熱性から鉄系、クロム系、ニッケル系などの金属であるが、銅は前記いずれの金属よりも熱伝達性に優れているからである。
【０００９】
【発明の実施の形態】
図１〜図７は本発明に係る多管式熱交換器を例示したもので、図１は同上多管式熱交換器のチューブシートの内壁面に銅めっき層または銅クラッド層を設けた例を示す要部拡大正面図、図２は同上多管式熱交換器のハブの内壁面に銅めっき層または銅クラッド層を設けた例を示す要部拡大正面図、図３は同上多管式熱交換器のバッフルプレートの表面を銅めっき層または銅クラッド層で被覆した例を示す要部拡大正面図、図４は同上多管式熱交換器の伝熱管に銅めっき層または銅クラッド層を施した例を示す要部拡大正面図、図５は同上の多管式熱交換器において、銅めっき層または銅クラッド層を施した伝熱管を管軸方向に傾斜したり、あるいは特願平１０−３３８１９５号に示したようにスパイラル状に弯曲して配管した例を示す要部拡大正面図、図６は銅めっき層または銅クラッド層を施した伝熱管を有する多管式熱交換器を傾斜設置した例を示す要部拡大正面図であり、図７は同上の多管式熱交換器において、伝熱管相互間または各伝熱管に板状または棒状の放熱部材を取付けた例を示し、（Ａ）は要部拡大正面図、（Ｂ）は（Ａ）のイーイ線上の断面図、（Ｃ）は図（Ａ）、（Ｂ）の変形例を示す図（Ｂ）相当図であり、７はハブ、８は放熱部材、９は冷却水である。なおここではＥＧＲガスの冷却に利用される多管式熱交換器を例にとり説明する。
【００１０】
まず図１に示す多管式熱交換器は、図８、図９に示す多管式熱交換器に本発明を適用した例で、両端部に冷却媒体流入口１−１および冷却媒体流出口１−２を設けた胴管１内部において、ＳＵＳ３１６製のストレート管の伝熱管２−１で構成された伝熱管群２の両端部が板金製のチューブシート３にろう付けにより固着配列され、該伝熱管群２の中間部はバッフルプレート５にて支持されており、一方、チューブシート３はその外周端部を胴管１にろう付けにより固着され、前記胴管１の一方の端部にはＥＧＲガスの流入口４−１が設けられた端部キャップ４が固着され、また他方の端部にはＥＧＲガスの流出口４−２が設けられた端部キャップ４が固着された構成となし、かつ前記端部キャップ４のガス流入口４−１およびガス流出口４−２の外側開口端部に締結用フランジ６が外嵌固着された構造の多管式熱交換器の前記チューブシート３の内壁面に銅めっき層または銅クラッド層からなる被覆層３−１を設け、各伝熱管２−１の両端部の外表面が前記被覆層３−１に接するように構成したものである。なお、チューブシート３の材質としては例えばＳＵＳ３１６などである。
【００１１】
上記図１に示す多管式熱交換器において、冷却水量が何等かの原因により減少して胴管１内の水位が下がり胴管１の上側内周面近傍の伝熱管２−１が水面より露出した場合、当該伝熱管２−１はその外表面の温度が当該伝熱管内を通過する高温流体により上昇するも、その外表面の熱はチューブシート３の内壁面に設けた銅めっき層または銅クラッド層からなる被覆層３−１を伝って冷却水９中に放熱されるため、冷却水９の水面より露出した伝熱管２−１の外表面温度が極端に上昇することはなくなり、ろう付け継手部の破壊や伝熱管の伸びによる座屈や曲がりなどの損傷を生じるような応力が発生することはない。
【００１２】
つぎに、図２に示す多管式熱交換器は、胴管１の両端部に冷却媒体流入口１−１および冷却媒体流出口（図面省略）を有する材質がＳＣＳ１４製のハブ７が固着され、このハブ７に伝熱管２−１で構成された伝熱管群２の両端部が固着配列され、かつ該ハブ７に端部キャップ４が取着された構造であって、前記ハブ７の伝熱管群固着内壁面に銅めっき層または銅クラッド層からなる被覆層７−１を設け、各伝熱管２−１の両端部の外表面が前記被覆層７−１に接するように構成したものである。したがって、この多管式熱交換器の場合は、胴管１内の冷却水の水面より露出した伝熱管２−１の外表面の熱は、ハブ７の伝熱管群固着内壁面に設けた銅めっき層または銅クラッド層からなる被覆層３−１を伝って冷却水９中に放熱されることとなるので、冷却水の水面より露出した伝熱管２−１の外表面温度が極端に上昇することはない。
【００１３】
また、図３に示す多管式熱交換器は、胴管１内に固着配列された伝熱管群２の中間部を支持するバッフルプレート５の外表面に銅めっき層または銅クラッド層からなる被覆層５−１を設け、該被覆層５−１と伝熱管２−１の外表面が接するように構成したものである。したがってこの多管式熱交換器の場合は、胴管１内の冷却水９の水面より露出した伝熱管２−１の外表面の熱はバッフルプレート５の外表面に設けた銅めっき層または銅クラッド層からなる被覆層５−１を伝って冷却水９中に放熱されることとなるので、冷却水９の水面より露出した伝熱管２−１の外表面温度が極端に上昇することはない。
【００１４】
図４に示す多管式熱交換器は、胴管１内に固着配列された伝熱管群２において、少なくとも胴管１内の冷却水９の水面より露出する伝熱管２−１を銅めっき層または銅クラッド層を有する管で構成した例で、ここでは伝熱管２−１を銅クラッド管で構成した例を示す。すなわち、伝熱管２−１はＳＵＳ３０４製の内管２−１ａと外管２−１ｂの間に銅クラッド層２−１ｃを設けた３層構造のパイプで構成されている。したがって胴管１内の冷却水９の水面より伝熱管２−１の外表面の一部が露出した場合には、その露出した当該伝熱管２−１の外表面の熱はＳＵＳ３０４製の内管２−１ａと外管２−１ｂおよび銅クラッド層２−１ｃを伝って冷却水９中に放熱されることとなり、冷却水９の水面より一部が露出した伝熱管２−１の外表面温度が極端に上昇することはない。
【００１５】
図５に示す多管式熱交換器は、胴管１内に固着配列された伝熱管群２において、少なくとも胴管１の上側内周面近傍の伝熱管２−１の一部が冷却水９中に浸漬されるように傾斜したり、あるいは特願平１０−３３８１９５号に示したようにスパイラル状に弯曲して設置するもので、その伝熱管２−１としてはより放熱効果を得るため例えば銅めっき層または銅クラッド層からなる被覆層２−１ｄを有する管を使用し、この被覆層２−１ｄを有する伝熱管２−１を図示のごとく当該伝熱管の一部が冷却水９中に浸漬されるように長手方向に傾斜して設置する。したがってこの多管式熱交換器において、胴管１内の冷却水の水位が低下した場合、傾斜あるいはスパイラル状に弯曲設置した伝熱管２−１の管軸方向長さの一部は水位が低下した胴管１内の冷却水９の水面より上方に露出するも、該伝熱管２−１の他部は水中に存在するので、水面より上方に露出した部分が高温流体で加熱されても、水中に存在している部分で冷却されるので露出部分も間接的に冷却されて高温流体の温度よりはかなり低温となる。
【００１６】
また、図６は伝熱管２群が胴管１の管軸と平行に配列した通常の多管式熱交換器の少なくとも胴管１の上側内周面近傍の伝熱管２−１を上記図５に示す銅めっき層または銅クラッド層からなる被覆層２−１ｄを有する伝熱管２−１に替え、この多管式熱交換器本体を傾斜して設置することにより、胴管１内の冷却水の水位が低下した場合伝熱管２−１の管軸方向長さの一部が胴管１内の冷却水９の水面より上方に露出するも、該伝熱管２−１の他部は水中に浸漬された状態となるので、図５と同様に水面より上方に露出した部分が高温流体で加熱されても、水中に存在している部分で冷却されるので露出部分も間接的に冷却されて高温流体の温度よりはかなり低温となる。
【００１７】
一方、図７に示す多管式熱交換器は、両端部に冷却媒体流入口および冷却媒体流出口が設けられた胴管の内壁の両端部付近に固定されたチューブシートまたはハブに伝熱管群が固着配列された通常の多管式熱交換器において、少なくとも胴管１の上側内周面近傍の伝熱管２−１に板状の放熱部材８を取付けた例であり、（Ａ）（Ｂ）は伝熱管２−１の相互間に放熱部材８を掛け渡すとともに該放熱部材の両端部をカシメ、好ましくはろう付けまたは溶接にて伝熱管２−１に固着した例であり、（Ｃ）は胴管１の上側内周面近傍の伝熱管２−１に板状の放熱部材８−１をその下側が冷却水中に浸漬されるようにカシメ、ろう付けまたは溶接にて固着した例である。したがって胴管１内の冷却水９の水面より伝熱管２−１の外表面の一部が露出した場合には、その露出した当該伝熱管２−１の外表面の熱は放熱部材８または放熱部材８−１を伝って冷却水９中に放熱されることとなり、冷却水９の水面より一部が露出した伝熱管２−１の外表面温度が極端に上昇することはない。
【００１８】
【発明の効果】
本発明は上記のごとく構成してなるから、何等かの原因で胴管内の冷却媒体のレベルが低下して胴管の上側内壁付近の伝熱管がその冷却媒体レベルより露出し、当該伝熱管の外表面温度が上昇しても、その熱はチューブシートの内壁面またはハブの内壁面またはバッフルプレートに設けた銅めっき層または銅クラッド層、または伝熱管自体に設けた銅めっき層または銅クラッド層、あるいは伝熱管に装着した板状または棒状の放熱部材により冷却媒体中に放熱されるので、伝熱管の管外表面温度が極端に上昇することがなくなり、熱応力が軽減されることにより伝熱管の伸びを抑制することが可能となり、伝熱管の熱膨張に伴うチューブシートとのろう付け部あるいは溶接部の破壊や、伝熱管の曲がりや座屈などを防止できるので、胴管内の冷却水の水位が低下しても熱交換性能の低下を防止できるとともに、冷却装置の寿命を延ばすことができるという優れた効果を奏する。
【図面の簡単な説明】
【図１】チューブシートの内壁面に銅めっき層または銅クラッド層を設けた多管式熱交換器の一例を示す要部拡大正面図である。
【図２】ハブの内壁面に銅めっき層または銅クラッド層を設けた多管式熱交換器の一例を示す要部拡大正面図である。
【図３】バッフルプレートの表面を銅めっき層または銅クラッド層で被覆した多管式熱交換器の一例を示す要部拡大正面図である。
【図４】表面に銅めっき層または銅クラッド層を施した伝熱管を用いた多管式熱交換器の一例を示す要部拡大正面図である。
【図５】表面に銅めっき層または銅クラッド層を施した伝熱管を管軸方向に傾斜して配管した多管式熱交換器例の一例を示す要部拡大正面図である。
【図６】表面に銅めっき層または銅クラッド層を施した伝熱管を傾斜設置して構成した多管式熱交換器の一例を示す要部拡大正面図である。
【図７】伝熱管相互間または各伝熱管に板状または棒状の放熱部材を取付けた多管式熱交換器例の一例を示し、（Ａ）は要部拡大正面図、（Ｂ）は（Ａ）のイーイ線上の断面図、（Ｃ）は図（Ａ）、（Ｂ）の変形例を示す図（Ｂ）相当図である。
【図８】本発明の対象とする従来の多管式のＥＧＲガス冷却装置の一例を中央部を省略して示す横断平面図である。
【図９】図８Ａ−Ａ線上の断面図である。
【符号の説明】
１胴管
１−１冷却水入口
１−２冷却水出口
２伝熱管群
２−１伝熱管
２−１ａ内管
２−１ｂ外管
２−１ｃ銅クラッド層
２−１ｄ被覆層
３チューブシート
４端部キャップ
４−１高温流体流入口
４−２高温流体流出口
５バッフルプレート
６締結用フランジ
７ハブ
８、８−１放熱部材
９冷却水[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multi-tube heat exchanger used for cooling EGR gas, for example.
[0002]
[Prior art]
For example, a multi-tube heat exchanger used as a device for cooling EGR gas with engine coolant or the like has a cooling medium inlet 1-1 and cooling at both ends as shown in FIGS. Inside the trunk tube 1 provided with the medium outlet 1-2, both ends of the heat transfer tube group 2 composed of the straight heat transfer tubes 2-1 are fixedly arranged to the tube sheet 3 made of sheet metal by brazing, The intermediate portion of the heat transfer tube group 2 is supported by a baffle plate 5, while the tube sheet 3 is fixed to the barrel tube 1 by brazing at the outer peripheral end thereof, and is attached to one end portion of the barrel tube 1. An end cap 4 provided with an EGR gas inlet 4-1 is fixed, and an end cap 4 provided with an EGR gas outlet 4-2 is fixed to the other end. And the gas inlet of the end cap 4 -1 and that the fastening flange 6 on the outer open end of the gas outlet 4-2 is in the fitted fixed structure is common.
[0003]
[Problems to be solved by the invention]
However, in the above-described conventional multi-tube heat exchanger, when cooling EGR gas using cooling water such as engine coolant as a refrigerant, there is a problem when the cooling water is filled in the trunk pipe 1. However, for example, the amount of cooling water of the engine decreases due to some cause, the water level in the trunk tube 1 falls, and a part of the heat transfer tube group 2 in the vicinity of the upper inner peripheral surface of the trunk tube 1 is exposed from the water surface. Is present, the temperature of the outer surface rises to the temperature of the EGR gas passing through the heat transfer tube, and as a result, a high thermal stress is generated and breaks from the brazed joint or is transferred between the tube sheets 3. The heat pipe stretches and buckles and bends, causing a problem that the life of the EGR gas cooling device is shortened. Also, if a part of the heat transfer tube is exposed from the water surface, the heat transfer tube is hardly cooled, so the heat exchange performance is also lowered. Then Cause a problem.
[0004]
The present invention has been made in order to solve the above-described problems of the conventional multi-tube heat exchanger. For some reason, the water level of the cooling water in the trunk tube is lowered and the heat transfer tube in the vicinity of the upper inner peripheral surface of the trunk tube. Even if a part of the group is exposed from the water surface and the temperature of the outer surface rises, cooling is performed by preventing the heat transfer tube from buckling or bending by using a means that dissipates the heat into the cooling water in the tube. An object of the present invention is to provide a multitubular heat exchanger that can extend the life of the apparatus and prevent deterioration of heat exchange performance.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has a heat transfer tube group fixedly arranged on a tube sheet or a hub fixed near both ends of an inner wall of a trunk tube provided with a cooling medium inlet and a cooling medium outlet at both ends. The heat transfer tube group is supported by a baffle plate in the middle, and end caps are fixed to both ends of the trunk tube, and an inlet and an outlet for high-temperature fluid are provided on the end cap. In the multi-tube heat exchanger having a structure in which a fastening flange is externally fitted and fixed to outer opening ends of the high-temperature fluid inlet and outlet of the end cap, A part of the heat transfer tube group in the vicinity of the upper inner peripheral surface is provided with means capable of transferring heat of the heat transfer surface when the temperature of the outer surface rises due to exposure from the water surface into the cooling medium in the trunk tube, The first embodiment is a cooling medium level in the trunk tube. The inner wall surface of the tube sheet, the inner wall surface of the hub, or the outer surface of the baffle plate exposed at least from the cooling medium water surface is covered with a copper plating layer or a copper clad layer. The embodiment is characterized in that when the cooling medium level in the trunk pipe is lowered, at least the heat transfer pipe exposed from the water surface of the cooling medium is constituted by a pipe having a copper plating layer or a copper clad layer. A heat transfer tube constituted by a tube having a copper plating layer or a copper clad layer is arranged so as to be inclined in the tube axis direction, and the fourth embodiment is at least cooled when the cooling medium level in the trunk tube is lowered. A plate-like or rod-like heat radiating member is attached between the heat transfer tubes exposed from the medium water surface or between the heat transfer tubes so that a part of the heat transfer tubes is immersed in the cooling medium. It is intended to.
[0006]
In the present invention, when the level of the cooling medium in the trunk pipe decreases, at least the inner wall surface of the tube sheet, the inner wall surface of the hub, or the surface of the baffle plate exposed from the water surface of the cooling medium is coated with a copper plating layer or a copper clad layer. This is because the heat of the outer surface of the heat transfer tube that has become hot is dissipated into the cooling medium through the copper plating layer or copper clad layer formed on the inner wall surface of the tube sheet, the inner wall surface of the hub, or the surface of the baffle plate. It is. In addition, the heat transfer tube exposed at least from the cooling medium water surface is composed of a tube having a copper plating layer or a copper clad layer. The heat of the outer surface of the heat transfer tube that has reached a high temperature is transferred to the copper plating layer or copper clad layer of the heat transfer tube. This is because heat is radiated into the cooling medium via the. Furthermore, a plate-like or rod-like heat radiating member is attached at least between the heat transfer tubes exposed from the cooling medium water surface or between the heat transfer tubes so that a part of the heat transfer tube is immersed in the cooling medium. This is because heat on the surface is radiated into the cooling medium through the heat radiating member.
[0007]
That is, if for some reason the level of the cooling medium in the trunk pipe falls to such a level that the heat transfer pipe near the upper inner wall of the trunk pipe is exposed from the level of the cooling medium in the trunk pipe, the heat transfer pipe exposed from the cooling medium level The temperature of the outer surface of the tube rises due to the heat of the high-temperature fluid flowing through the tube, but the heat is a copper plating layer or copper clad layer provided on the inner wall surface of the tube sheet, the inner wall surface of the hub or the baffle plate, or Because the heat is dissipated in the cooling medium by the copper plating layer or the copper clad layer provided on the heat transfer tube itself, or the plate-like or rod-like heat dissipation member attached to the heat transfer tube, the outer surface temperature of the heat transfer tube is extremely increased. Since the thermal stress is reduced, the elongation of the heat transfer tube can be suppressed.
[0008]
The reason why the copper plating layer or the copper clad layer is used as the heat transfer means in the present invention is as follows.
That is, the components of the multi-tubular heat exchanger used at high temperatures are metals such as iron-based, chromium-based, and nickel-based due to their heat resistance, but copper has better heat transfer properties than any of the above metals. Because.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
1 to 7 exemplify a multitubular heat exchanger according to the present invention, and FIG. 1 shows an example in which a copper plating layer or a copper clad layer is provided on the inner wall surface of the tube sheet of the multitubular heat exchanger. FIG. 2 is an enlarged front view of the main part showing an example in which a copper plating layer or a copper clad layer is provided on the inner wall surface of the hub of the multi-tubular heat exchanger. FIG. Fig. 4 is an enlarged front view of the main part showing an example in which the surface of the baffle plate of the heat exchanger is coated with a copper plating layer or a copper clad layer. Fig. 4 shows a copper plating layer or a copper clad layer on the heat transfer tube of the multitubular heat exchanger. FIG. 5 is an enlarged front view of a main portion showing an example of application, and FIG. 5 is a multi-tube heat exchanger same as the above, in which a heat transfer tube provided with a copper plating layer or a copper clad layer is inclined in the tube axis direction or As shown in No. 338195, the main part is expanded to show an example of a pipe bent in a spiral shape. FIG. 6 is an enlarged front view of the main part showing an example in which a multi-tube heat exchanger having a heat transfer tube having a copper plating layer or a copper clad layer is installed at an angle, and FIG. In an exchanger, the example which attached the plate-shaped or rod-shaped heat radiating member between heat exchanger tubes or each heat exchanger tube is shown, (A) is a principal part enlarged front view, (B) is sectional drawing on the Ea line of (A). (C) is a figure (B) equivalent figure which shows the modification of figure (A), (B), 7 is a hub, 8 is a thermal radiation member, 9 is cooling water. Here, a multi-tube heat exchanger used for cooling the EGR gas will be described as an example.
[0010]
First, the multi-tube heat exchanger shown in FIG. 1 is an example in which the present invention is applied to the multi-tube heat exchanger shown in FIGS. 8 and 9, and a cooling medium inlet 1-1 and a cooling medium outlet are provided at both ends. In the body tube 1 provided with 1-2, both ends of the heat transfer tube group 2 constituted by the heat transfer tube 2-1 of a straight tube made of SUS316 are fixedly arranged to the tube sheet 3 made of sheet metal by brazing, The intermediate portion of the heat transfer tube group 2 is supported by a baffle plate 5, while the tube sheet 3 is fixed to the barrel tube 1 by brazing at the outer peripheral end thereof, and is attached to one end portion of the barrel tube 1. An end cap 4 provided with an EGR gas inlet 4-1 is fixed, and an end cap 4 provided with an EGR gas outlet 4-2 is fixed to the other end. And the gas inlet 4-1 and the gas outlet 4- of the end cap 4 A coating layer 3-1 made of a copper plating layer or a copper clad layer is provided on the inner wall surface of the tube sheet 3 of the multi-tubular heat exchanger having a structure in which the fastening flange 6 is fitted and fixed to the outer opening end of The heat transfer tubes 2-1 are configured such that the outer surfaces of both end portions thereof are in contact with the coating layer 3-1. In addition, as a material of the tube sheet 3, it is SUS316 etc., for example.
[0011]
In the multitubular heat exchanger shown in FIG. 1, the amount of cooling water decreases due to some cause, the water level in the trunk tube 1 falls, and the heat transfer tube 2-1 in the vicinity of the upper inner peripheral surface of the trunk tube 1 moves from the water surface. When exposed, the heat transfer tube 2-1 has its outer surface temperature raised by the high-temperature fluid passing through the heat transfer tube, but the heat of the outer surface is a copper plating layer provided on the inner wall surface of the tube sheet 3 or Since the heat is radiated into the cooling water 9 through the coating layer 3-1 made of the copper clad layer, the outer surface temperature of the heat transfer tube 2-1 exposed from the water surface of the cooling water 9 will not be extremely increased. There will be no stress that would cause damage such as buckling or bending due to breakage of the spliced joint or elongation of the heat transfer tube.
[0012]
Next, the multi-tube heat exchanger shown in FIG. 2 has a hub 7 made of SCS14 made of a material having a cooling medium inlet 1-1 and a cooling medium outlet (not shown) at both ends of the trunk tube 1. Both ends of the heat transfer tube group 2 constituted by the heat transfer tubes 2-1 are fixedly arranged on the hub 7 and the end cap 4 is attached to the hub 7. A coating layer 7-1 made of a copper plating layer or a copper clad layer is provided on the inner wall surface fixed to the heat tube group, and the outer surfaces of both end portions of each heat transfer tube 2-1 are in contact with the coating layer 7-1. is there. Therefore, in the case of this multitubular heat exchanger, the heat of the outer surface of the heat transfer tube 2-1 exposed from the surface of the cooling water in the trunk tube 1 is the copper provided on the heat transfer tube group fixed inner wall surface of the hub 7. Since heat is dissipated in the cooling water 9 through the coating layer 3-1 made of the plating layer or the copper clad layer, the outer surface temperature of the heat transfer tube 2-1 exposed from the water surface of the cooling water extremely increases. There is nothing.
[0013]
Further, the multi-tube heat exchanger shown in FIG. 3 has a coating made of a copper plating layer or a copper clad layer on the outer surface of a baffle plate 5 that supports an intermediate portion of a heat transfer tube group 2 fixedly arranged in the trunk tube 1. The layer 5-1 is provided, and the coating layer 5-1 is configured to be in contact with the outer surface of the heat transfer tube 2-1. Therefore, in the case of this multitubular heat exchanger, the heat of the outer surface of the heat transfer tube 2-1 exposed from the surface of the cooling water 9 in the trunk tube 1 is a copper plating layer or copper provided on the outer surface of the baffle plate 5. Since the heat is dissipated in the cooling water 9 through the coating layer 5-1 made of the clad layer, the outer surface temperature of the heat transfer tube 2-1 exposed from the water surface of the cooling water 9 does not extremely increase. .
[0014]
The multitubular heat exchanger shown in FIG. 4 has a copper plating layer in which the heat transfer tubes 2-1 exposed at least from the water surface of the cooling water 9 in the trunk tube 1 in the heat transfer tube group 2 fixedly arranged in the trunk tube 1 are formed. Or it is the example comprised with the pipe | tube which has a copper clad layer, and the example which comprised the heat exchanger tube 2-1 with the copper clad pipe here is shown. That is, the heat transfer tube 2-1 is configured by a three-layered pipe in which a copper clad layer 2-1c is provided between an inner tube 2-1a and an outer tube 2-1b made of SUS304. Therefore, when a part of the outer surface of the heat transfer tube 2-1 is exposed from the water surface of the cooling water 9 in the trunk tube 1, the heat of the exposed outer surface of the heat transfer tube 2-1 is the inner tube made of SUS304. 2-1a, the outer tube 2-1b, and the copper clad layer 2-1c are radiated into the cooling water 9 through the outer surface temperature of the heat transfer tube 2-1 that is partially exposed from the water surface of the cooling water 9. Will not rise extremely.
[0015]
The multitubular heat exchanger shown in FIG. 5 is configured such that, in the heat transfer tube group 2 fixedly arranged in the body tube 1, at least a part of the heat transfer tube 2-1 near the upper inner peripheral surface of the body tube 1 is the cooling water 9. In order to obtain a more heat radiation effect, the heat transfer tube 2-1 is inclined so as to be immersed therein or bent in a spiral shape as shown in Japanese Patent Application No. 10-338195. A pipe having a coating layer 2-1d made of a copper plating layer or a copper clad layer is used, and a part of the heat transfer tube 2-1 having the coating layer 2-1d is placed in the cooling water 9 as shown in the figure. Inclined in the longitudinal direction so as to be immersed. Therefore, in this multi-tube heat exchanger, when the cooling water level in the trunk pipe 1 is lowered, the water level is reduced for a part of the length in the tube axis direction of the heat transfer pipe 2-1 that is installed in an inclined or spiral shape. Even though the other portion of the heat transfer tube 2-1 is present in the water, the portion exposed above the water surface is heated with a high-temperature fluid. Since it cools in the part which exists in water, an exposed part is also cooled indirectly and becomes a low temperature rather than the temperature of a hot fluid.
[0016]
6 shows at least the heat transfer tube 2-1 in the vicinity of the upper inner peripheral surface of the body tube 1 of a normal multi-tube heat exchanger in which two heat transfer tubes are arranged in parallel with the tube axis of the body tube 1. FIG. In place of the heat transfer tube 2-1 having a coating layer 2-1d made of a copper plating layer or a copper clad layer shown in FIG. When the water level of the heat transfer tube 2-1 is lowered, a part of the length in the tube axis direction of the heat transfer tube 2-1 is exposed above the water surface of the cooling water 9 in the trunk tube 1, but the other part of the heat transfer tube 2-1 is underwater. Since it is immersed, even if the part exposed above the surface of the water is heated with a high-temperature fluid, the exposed part is also indirectly cooled because it is cooled in the part existing in the water. The temperature is much lower than that of the hot fluid.
[0017]
On the other hand, the multitubular heat exchanger shown in FIG. 7 has a heat transfer tube group on a tube sheet or a hub fixed near both ends of the inner wall of the trunk tube provided with a cooling medium inlet and a cooling medium outlet at both ends. Is an example in which a plate-like heat radiating member 8 is attached to at least the heat transfer tube 2-1 in the vicinity of the upper inner peripheral surface of the trunk tube 1. ) Is an example in which the heat radiating member 8 is stretched between the heat transfer tubes 2-1, and both ends of the heat radiating members are fixed to the heat transfer tubes 2-1 by caulking, preferably brazing or welding. Is an example in which a plate-like heat radiation member 8-1 is fixed to the heat transfer tube 2-1 in the vicinity of the upper inner peripheral surface of the trunk tube 1 by caulking, brazing or welding so that the lower side is immersed in cooling water. . Therefore, when a part of the outer surface of the heat transfer tube 2-1 is exposed from the water surface of the cooling water 9 in the trunk tube 1, the heat of the exposed outer surface of the heat transfer tube 2-1 is absorbed by the heat radiating member 8 or the heat dissipation. Heat is dissipated in the cooling water 9 through the member 8-1, and the outer surface temperature of the heat transfer tube 2-1 that is partially exposed from the water surface of the cooling water 9 does not rise extremely.
[0018]
【The invention's effect】
Since the present invention is configured as described above, for some reason, the level of the cooling medium in the trunk pipe is lowered, and the heat transfer pipe near the upper inner wall of the trunk pipe is exposed from the cooling medium level. Even if the outer surface temperature rises, the heat is applied to the inner wall surface of the tube sheet, the inner wall surface of the hub or the baffle plate, or the copper plating layer or copper clad layer provided on the heat transfer tube itself. Alternatively, heat is radiated into the cooling medium by a plate-like or rod-like heat radiating member attached to the heat transfer tube, so that the temperature of the outer surface of the heat transfer tube does not increase excessively, and the heat stress is reduced by reducing the heat stress. It is possible to suppress the elongation of the heat transfer tube and prevent breakage of the brazed portion or welded portion with the tube sheet accompanying the thermal expansion of the heat transfer tube, bending or buckling of the heat transfer tube, etc. Decreases with the possible prevention of the heat exchanger performance level of 却水 is reduced, an excellent effect that it is possible to extend the life of the cooling system.
[Brief description of the drawings]
FIG. 1 is an enlarged front view of an essential part showing an example of a multitubular heat exchanger in which a copper plating layer or a copper clad layer is provided on the inner wall surface of a tube sheet.
FIG. 2 is an enlarged front view of a main part showing an example of a multi-tube heat exchanger in which a copper plating layer or a copper clad layer is provided on the inner wall surface of a hub.
FIG. 3 is a main part enlarged front view showing an example of a multi-tube heat exchanger in which the surface of a baffle plate is covered with a copper plating layer or a copper clad layer.
FIG. 4 is a main part enlarged front view showing an example of a multi-tube heat exchanger using a heat transfer tube having a copper plated layer or a copper clad layer on the surface.
FIG. 5 is a main part enlarged front view showing an example of a multi-tube heat exchanger in which a heat transfer tube having a copper plating layer or a copper clad layer on the surface thereof is inclined in the tube axis direction.
FIG. 6 is an enlarged front view of an essential part showing an example of a multi-tube heat exchanger configured by inclining a heat transfer tube having a copper plated layer or a copper clad layer on its surface.
FIGS. 7A and 7B show an example of a multi-tube heat exchanger in which plate-like or rod-like heat radiating members are attached to each other or between each heat transfer tube. FIG. 7A is an enlarged front view of the main part, and FIG. Sectional drawing on the Ea line of A), (C) is a figure (B) equivalent figure which shows the modification of figure (A), (B).
FIG. 8 is a cross-sectional plan view showing an example of a conventional multi-tube EGR gas cooling device that is the subject of the present invention, with the central portion omitted.
9 is a cross-sectional view taken along the line AA in FIG.
[Explanation of symbols]
1 Body tube 1-1 Cooling water inlet 1-2 Cooling water outlet 2 Heat transfer tube group 2-1 Heat transfer tube 2-1a Inner tube 2-1b Outer tube 2-1c Copper clad layer 2-1d Covering layer 3 Tube sheet 4 End Cap 4-1 High-temperature fluid inlet 4-2 High-temperature fluid outlet 5 Baffle plate 6 Fastening flange 7 Hub 8, 8-1 Heat radiation member 9 Cooling water

Claims

A heat transfer tube group is fixedly arranged on a tube sheet or a hub fixed near both ends of the inner wall of the trunk tube provided with a cooling medium inlet and a cooling medium outlet at both ends, and the heat transfer tube group is an intermediate portion thereof Further, end caps are fixed to both ends of the barrel tube, and an inlet and an outlet for high-temperature fluid are provided on the end cap, and the high-temperature fluid flow of the end cap is provided. In a multitubular heat exchanger having a structure in which a fastening flange is fitted and fixed to outer opening ends of an inlet and an outlet, the tube exposed at least from the cooling medium level when the cooling medium level in the trunk pipe is lowered A multitubular heat exchanger characterized in that an inner wall surface of a sheet, an inner wall surface of a hub, or an outer surface of a baffle plate is coated with a copper plating layer or a copper clad layer.

A heat transfer tube group is fixedly arranged on a tube sheet or a hub fixed near both ends of the inner wall of the trunk tube provided with a cooling medium inlet and a cooling medium outlet at both ends, and the heat transfer tube group is an intermediate portion thereof Further, end caps are fixed to both ends of the barrel tube, and an inlet and an outlet for high-temperature fluid are provided on the end cap, and the high-temperature fluid flow of the end cap is provided. In a multitubular heat exchanger having a structure in which a fastening flange is fitted and fixed to outer opening ends of an inlet and an outlet, when the cooling medium level in the trunk pipe decreases, at least the heat transfer pipe exposed from the cooling medium level Is composed of a tube having a copper plating layer or a copper clad layer.

3. The multi-tube heat exchanger according to claim 2, wherein the heat transfer tubes made of tubes having a copper plating layer or a copper clad layer are arranged so as to be inclined in the tube axis direction.

A heat transfer tube group is fixedly arranged on a tube sheet or a hub fixed near both ends of the inner wall of the trunk tube provided with a cooling medium inlet and a cooling medium outlet at both ends, and the heat transfer tube group is an intermediate portion thereof Further, end caps are fixed to both ends of the barrel tube, and an inlet and an outlet for high-temperature fluid are provided on the end cap, and the high-temperature fluid flow of the end cap is provided. In a multitubular heat exchanger having a structure in which a fastening flange is fitted and fixed to the outer opening ends of the inlet and the outlet, when the cooling medium level in the trunk pipe is lowered, the transmission is exposed at least from the cooling medium level. A multi-tube heat exchanger characterized in that a plate-like or rod-like heat radiating member is attached between heat tubes or between each heat transfer tube so that a part thereof is immersed in a cooling medium.