EP0955384A2 - Process for quenching workpieces with gases and heat treating installation for carrying out said process - Google Patents
Process for quenching workpieces with gases and heat treating installation for carrying out said process Download PDFInfo
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- EP0955384A2 EP0955384A2 EP99104318A EP99104318A EP0955384A2 EP 0955384 A2 EP0955384 A2 EP 0955384A2 EP 99104318 A EP99104318 A EP 99104318A EP 99104318 A EP99104318 A EP 99104318A EP 0955384 A2 EP0955384 A2 EP 0955384A2
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- Prior art keywords
- heat exchanger
- refrigerant
- quenching
- heat
- workpieces
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
- C21D1/767—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material with forced gas circulation; Reheating thereof
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/56—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents
- C21D1/613—Gases; Liquefied or solidified normally gaseous material
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
- C21D1/773—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material under reduced pressure or vacuum
Definitions
- the invention relates to a method for quenching workpieces in a treatment chamber by means of a quenching gas, in which a heat exchanger is provided, through which the quenching gas is circulated for quenching the workpieces and which works with a refrigerant evaporating in the heat exchanger.
- the invention further relates to a heat treatment plant for carrying out the method.
- a method and a device of the above type are the subject of DE 44 22 588 C1.
- a cooling unit is arranged outside the treatment chamber in which the heat treatment takes place.
- the refrigerant is circulated through the heat exchanger in the treatment chamber and through the refrigeration unit, so that the heat absorbed in the treatment chamber can be dissipated to the outside.
- a refrigerant is selected which evaporates in the heat exchanger like in a refrigerator, so that the heat of vaporization can also be used for the cooling effect.
- the device according to DE 44 22 588 C1 is very complex because a cooling unit with a condenser and a compressor must be arranged outside the treatment chamber. Because the workpieces must be quenched as quickly as possible, it must be done in a relatively short time a lot of heat is dissipated, so that the condenser and the compressor must have a high output.
- the invention is based on the problem of designing a method of the type mentioned at the outset in such a way that the fastest possible quenching of workpieces within a treatment chamber is possible with as little equipment outlay as possible. Furthermore, a simple device for carrying out this method is to be found.
- the first-mentioned problem is solved according to the invention in that the heat exchanger is at least partially filled with the liquid refrigerant before the quenching process begins, while there is a vacuum in the treatment chamber, and in that the cooling of the quenching gas is effected by the cooling capacity of the heat exchanger and the evaporation of the filling quantity during the circulation Quench gas occurs while cooling a batch of workpieces.
- This procedure is based on the knowledge that the heat exchanger is thermally insulated from the batch by the vacuum in the treatment chamber. As a result, there is no undesired cooling of the workpieces and no convective heat absorption of the heat exchanger from the environment during the filling of liquid refrigerant into the heat exchanger of the treatment chamber. Only when the quenching gas is introduced into the treatment chamber and circulates in it and thereby flows through the heat exchanger does the heat supplied to the heat exchanger lead to heat exchange and in particular to an evaporation of the refrigerant. As a result of this evaporation, a great deal of heat is extracted from the quenching gas, so that the batch can be rapidly cooled in the upper temperature range, which is crucial for the quenching.
- the amount of coolant required is particularly low if, according to an advantageous development of the method, a heat exchanger with heat exchanger surfaces with high heat storage capacity is used.
- a heat exchanger can be cooled to a low temperature before the quenching phase, so that not only the refrigerant is available for the heat absorption during the quenching phase.
- the thermal insulation of the heat exchanger due to the prevailing vacuum also makes it possible to use a treatment chamber with a furnace area and the heat exchanger in a common housing and to fill the heat exchanger with the refrigerant while the furnace is working.
- the method according to the invention can also be used in a separate treatment chamber serving to quench workpieces, without a heater arranged therein.
- the inert gas is usually supplied in liquid form and converted into the gaseous state in the required amount in an inert gas supply system which has an evaporator.
- an inert gas supply system can be dispensed with if, according to another advantageous development of the invention, the evaporated refrigerant is collected in a gas collection container and used as an inert gas.
- At least part of the refrigerant evaporated to cool the quench gas can be used in the heat treatment system itself, if the evaporated refrigerant is used to flood the treatment chamber after quenching the workpieces.
- the inert gas can therefore be used during quenching to build up pressure from, for example, 1 bar to 6 bar, after quenching for further batches or within the system (with intermediate buffer) for other process chambers or as control gas.
- the refrigerant is particularly inexpensive and can be used as an inert gas if it is liquid nitrogen.
- other liquid gases can also be used, for example air.
- the second task namely the creation of a heat treatment system for carrying out the method according to the invention is achieved in that the heat exchanger is designed to be at least partially filled with the liquid refrigerant and that the cooling capacity of the heat exchanger is completely due to the evaporation of the filling quantity when the quenching gas is circulated Cooling of a batch of workpieces is dimensioned.
- Such a heat treatment system is very inexpensive to build because it does not require a refrigeration unit with a condenser and with a compressor for the refrigerant. Furthermore, it is able to cool the quenching gas particularly effectively because the refrigerant evaporates in the heat exchanger during the circulation of the quenching gas and therefore much heat is extracted from the quenching gas by the heat of vaporization absorbed by the refrigerant.
- the heat exchanger itself does not need to be redesigned, or only slightly, in comparison with the heat exchangers used with brine.
- the amount of refrigerant required to cool the quenching gas can be particularly low if the heat exchanger is equipped with heat exchanger surfaces with high heat storage capacity.
- the treatment chamber has a furnace area and the heat exchanger in a common housing.
- the evaporated refrigerant can be used for a further purpose if a gas collection container is provided for the refrigerant evaporated in the heat exchanger.
- the heat treatment system according to the invention requires a very particularly small amount of refrigerant to operate if, according to another development of the invention, two heat exchangers are connected in series in the treatment chamber and if only one heat exchanger is designed as an evaporator for the refrigerant, while the other heat exchanger is used to circulate a refrigerant or Water or heat transfer medium is connected to an external coolant unit.
- the drawing shows a treatment chamber 1, which has a heat exchanger 3 and a furnace area 4 in a common housing 2, in which there is a batch 5 with the workpieces to be treated.
- a fan 6 is arranged behind the heat exchanger 3, by means of which a quenching gas can be circulated within the treatment chamber 1 through the charge 5 and the heat exchanger 3.
- the drawing also shows a storage container 7 for liquid nitrogen. From this storage container 7, a smaller amount of nitrogen is filled into an intermediate container 8, from which liquid nitrogen can be filled into the heat exchanger 3 by opening a valve 9. Nitrogen evaporated in the heat exchanger 3 is able to reach a gas collecting container 11 via a line 10. Via a line 12 in which a valve 13 is connected, the pressure in the gas collection container 11 can be applied to the intermediate container 8 in order to press liquid nitrogen from the intermediate container 8 into the heat exchanger 3. The nitrogen evaporated in the heat exchanger 3 passes through a non-return valve 14 into the line 10 and thereby into the gas collection container 11. If the pressures are too high, a pressure relief valve 15 allows nitrogen to flow out into the atmosphere. To flood the treatment chamber 1 with nitrogen from the gas collection container 11, the line 10 is connected to the treatment chamber 1 via a valve 16.
- the heat treatment of a batch 5 is carried out under vacuum by first heating the batch 5 to, for example, 1000 ° C.
- the heat exchanger 3 is filled with liquid nitrogen from the intermediate container 8.
- the treatment chamber 1 is flooded by opening the valve 16 with gaseous nitrogen as the quenching gas and the fan 6 is switched on.
- the quenching gas circulates in the treatment chamber 1 between the charge 5 and through the heat exchanger 3. Since this takes heat from the charge 5 and thereby heats up, when the heat exchanger 3 flows through it, the liquid nitrogen previously filled in it evaporates and, as a result, heat is removed from the quenching gas.
- the evaporated nitrogen is able to reach the gas collection container 11 via the check valve 14 and the line 10.
- An overflow valve 17 makes it possible for gas to flow from the heat exchanger 3 into the treatment chamber 1 if the pressure in the heat exchanger 3 is too high (for example above 6 bar).
- the method according to the invention is also possible in systems in which the batch 5 is heated and quenched with the quenching gas in separate chambers. It is only essential for the method according to the invention that a vacuum prevails in the chamber receiving it during the cooling of the heat exchanger, so that the heat exchanger only begins to work effectively when the batch is to be cooled by means of the quenching gas.
- the method according to the invention also allows the vaporized gas to be reliquefied in a compressor system.
- the demands on the purity and quality of the evaporating gas (coolant) are low.
- the heat exchanger also works in non-evacuated chambers.
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- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatments In General, Especially Conveying And Cooling (AREA)
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Abstract
Description
Die Erfindung betrifft ein Verfahren zum Abschrecken von Werkstücken in einer Behandlungskammer mittels eines Abschreckgases, bei dem ein Wärmetauscher vorgesehen ist, durch welchen zum Abschrecken der Werkstücke das Abschreckgas umgewälzt wird und der mit einem in dem Wärmetauscher verdampfenden Kältemittel arbeitet. Weiterhin betrifft die Erfindung eine Wärmebehandlungsanlage zur Durchführung des Verfahrens.The invention relates to a method for quenching workpieces in a treatment chamber by means of a quenching gas, in which a heat exchanger is provided, through which the quenching gas is circulated for quenching the workpieces and which works with a refrigerant evaporating in the heat exchanger. The invention further relates to a heat treatment plant for carrying out the method.
Ein Verfahren und eine Vorrichtung der vorstehenden Art sind Gegenstand der DE 44 22 588 C1. Bei der in dieser Schrift beschriebenen Wärmebehandlungsanlage ist außerhalb der Behandlungskammer, in welcher die Wärmebehandlung stattfindet, ein Kälteaggregat angeordnet. Während der Abschreckphase wird das Kältemittel durch den Wärmetauscher in der Behandlungskammer und durch das Kälteaggregat im Kreis umgepumpt, so dass die in der Behandlungskammer aufgenommene Wärme nach außen abgeführt werden kann. Um eine möglichst rasche Abkühlung der Werkstücke zu erreichen, wird ein Kältemittel gewählt, welches wie in einem Kühlschrank in dem Wärmetauscher verdampft, so dass auch die Verdampfungswärme für den Kühleffekt genutzt werden kann.A method and a device of the above type are the subject of DE 44 22 588 C1. In the heat treatment system described in this document, a cooling unit is arranged outside the treatment chamber in which the heat treatment takes place. During the quenching phase, the refrigerant is circulated through the heat exchanger in the treatment chamber and through the refrigeration unit, so that the heat absorbed in the treatment chamber can be dissipated to the outside. In order to cool the workpieces as quickly as possible, a refrigerant is selected which evaporates in the heat exchanger like in a refrigerator, so that the heat of vaporization can also be used for the cooling effect.
Die Vorrichtung nach der DE 44 22 588 C1 ist sehr aufwendig, weil außerhalb der Behandlungskammer ein Kälteaggregat mit einem Verflüssiger und einem Verdichter angeordnet werden muss. Weil das Abschrecken der Werkstücke möglichst rasch zu erfolgen hat, muss in relativ kurzer Zeit viel Wärme abgeführt werden, so dass der Verflüssiger und der Verdichter eine hohe Leistung haben müssen.The device according to DE 44 22 588 C1 is very complex because a cooling unit with a condenser and a compressor must be arranged outside the treatment chamber. Because the workpieces must be quenched as quickly as possible, it must be done in a relatively short time a lot of heat is dissipated, so that the condenser and the compressor must have a high output.
Der Erfindung liegt das Problem zugrunde, ein Verfahren der eingangs genannten Art so auszugestalten, dass mit möglichst geringem apparativen Aufwand ein möglichst rasches Abschrecken von Werkstücken innerhalb einer Behandlungskammer möglich wird. Weiterhin soll eine einfache Vorrichtung zur Durchführung dieses Verfahrens gefunden werden.The invention is based on the problem of designing a method of the type mentioned at the outset in such a way that the fastest possible quenching of workpieces within a treatment chamber is possible with as little equipment outlay as possible. Furthermore, a simple device for carrying out this method is to be found.
Das erstgenannte Problem wird erfindungsgemäß dadurch gelöst, dass der Wärmetauscher vor Beginn des Abschreckvorganges mit dem flüssigen Kältemittel zumindest teilweise gefüllt wird, während in der Behandlungskammer Vakuum herrscht, und dass die Kühlung des Abschreckgases durch die Kühlkapazität des Wärmetauschers und das Verdampfen der Einfüllmenge beim Umwälzen des Abschreckgases während des Kühlens einer Charge von Werkstücken erfolgt.The first-mentioned problem is solved according to the invention in that the heat exchanger is at least partially filled with the liquid refrigerant before the quenching process begins, while there is a vacuum in the treatment chamber, and in that the cooling of the quenching gas is effected by the cooling capacity of the heat exchanger and the evaporation of the filling quantity during the circulation Quench gas occurs while cooling a batch of workpieces.
Diese Verfahrensweise baut auf der Erkenntnis auf, dass der Wärmetauscher durch das Vakuum in der Behandlungskammer thermisch von der Charge isoliert ist. Dadurch kommt es während des Einfüllens von flüssigem Kältemittel in den Wärmetauscher der Behandlungskammer zu keiner unerwünschten Abkühlung der Werkstücke und zu keiner konvektiven Wärmeaufnahme des Wärmetauschers aus der Umgebung. Erst wenn in die Behandlungskammer das Abschreckgas eingegeben wird und dieses in ihr zirkuliert und dabei durch den Wärmetauscher strömt, kommt es durch die dann dem Wärmetauscher zugeführte Wärme zu einem Wärmetausch und insbesondere zu einer Verdampfung des Kältemittels. Durch diese Verdampfung wird dem Abschreckgas sehr viel Wärme entzogen, so dass ein rasches Abkühlen der Charge im oberen, für die Abschreckung entscheidenden Temperaturbereich möglich wird.This procedure is based on the knowledge that the heat exchanger is thermally insulated from the batch by the vacuum in the treatment chamber. As a result, there is no undesired cooling of the workpieces and no convective heat absorption of the heat exchanger from the environment during the filling of liquid refrigerant into the heat exchanger of the treatment chamber. Only when the quenching gas is introduced into the treatment chamber and circulates in it and thereby flows through the heat exchanger does the heat supplied to the heat exchanger lead to heat exchange and in particular to an evaporation of the refrigerant. As a result of this evaporation, a great deal of heat is extracted from the quenching gas, so that the batch can be rapidly cooled in the upper temperature range, which is crucial for the quenching.
Die erforderliche Kühlmittelmenge ist besonders gering, wenn gemäß einer vorteilhaften Weiterbildung des Verfahrens ein Wärmetauscher mit Wärmetauscherflächen von hohem Wärmespeichervermögen verwendet wird. Einen solchen Wärmetauscher kann man bereits vor der Abschreckphase auf eine niedrige Temperatur abkühlen, so dass während der Abschreckphase für die Wärmeaufnahme nicht nur das Kältemittel zur Verfügung steht.The amount of coolant required is particularly low if, according to an advantageous development of the method, a heat exchanger with heat exchanger surfaces with high heat storage capacity is used. Such a heat exchanger can be cooled to a low temperature before the quenching phase, so that not only the refrigerant is available for the heat absorption during the quenching phase.
Durch die thermische Isolation des Wärmetauschers aufgrund des herrschenden Vakuums wird es auch möglich, eine Behandlungskammer mit einem Ofenbereich und den Wärmetauscher in einem gemeinsamen Gehäuse zu verwenden und den Wärmetauscher mit dem Kältemittel während des Arbeitens des Ofens zu befüllen. Das erfindungsgemäße Verfahren ist jedoch auch bei einer separaten, der Abschreckung von Werkstücken dienenden Behandlungskammer ohne eine darin angeordnete Heizung anwendbar.The thermal insulation of the heat exchanger due to the prevailing vacuum also makes it possible to use a treatment chamber with a furnace area and the heat exchanger in a common housing and to fill the heat exchanger with the refrigerant while the furnace is working. However, the method according to the invention can also be used in a separate treatment chamber serving to quench workpieces, without a heater arranged therein.
In Fertigungsstätten, in welchen das erfindungsgemäße Verfahren Anwendung findet, gibt es in aller Regel verschiedene Einrichtungen, welche eine Versorgung mit Inertgas erfordern. Üblicherweise wird hierzu das Inertgas flüssig angeliefert und in einer Inertgas-Versorgungsanlage, welche einen Verdampfer aufweist, in der benötigten Menge in den gasförmigen Zustand überführt. Auf eine solche Inertgas-Versorgungsanlage kann man verzichten, wenn gemäß einer anderen vorteilhaften Weiterbildung der Erfindung das verdampfte Kältemittel in einem Gassammelbehälter gesammelt und als Inertgas weiterverwendet wird.In manufacturing plants in which the method according to the invention is used, there are generally various devices which require a supply of inert gas. For this purpose, the inert gas is usually supplied in liquid form and converted into the gaseous state in the required amount in an inert gas supply system which has an evaporator. Such an inert gas supply system can be dispensed with if, according to another advantageous development of the invention, the evaporated refrigerant is collected in a gas collection container and used as an inert gas.
Zumindest ein Teil des zum Kühlen des Abschreckgases verdampften Kältemittels kann in der Wärmebehandlungsanlage selbst weiterverwendet werden, wenn das verdampfte Kältemittel zum Fluten der Behandlungskammer nach dein Abschrecken der Werkstücke verwendet wird. Das Inertgas kann also während des Abschreckens zum Druckaufbau von z.B. 1 bar auf 6 bar, nach dem Abschrecken für weitere Chargen oder innerhalb der Anlage (mit Zwischenpuffer) für andere Prozesskammern oder als Steuergas verwendet werden.At least part of the refrigerant evaporated to cool the quench gas can be used in the heat treatment system itself, if the evaporated refrigerant is used to flood the treatment chamber after quenching the workpieces. The inert gas can therefore be used during quenching to build up pressure from, for example, 1 bar to 6 bar, after quenching for further batches or within the system (with intermediate buffer) for other process chambers or as control gas.
Besonders kostengünstig ist das Kältemittel erhältlich und gut als Inertgas verwendbar, wenn es flüssiger Stickstoff ist. Es sind jedoch auch andere Flüssiggase verwendbar, zum Beispiel Luft.The refrigerant is particularly inexpensive and can be used as an inert gas if it is liquid nitrogen. However, other liquid gases can also be used, for example air.
Wenn man die Kältemittelmenge möglichst gering halten will, damit alles verdampfte Kältemittel wieder gebraucht werden kann, dann ist es möglich, eine Behandlungskammer mit zwei hintereinander geschalteten Wärmetauschern zu verwenden. Ein zum Beispiel mit Wasser betriebener Wärmetauscher könnte dem "Flüssiggas-Wärmetauscher" vorgeschaltet werden.If you want to keep the amount of refrigerant as small as possible so that all evaporated refrigerant can be used again, then it is possible to use a treatment chamber with two heat exchangers connected in series. A heat exchanger operated, for example, with water could be connected upstream of the "liquid gas heat exchanger".
Die zweitgenannnte Aufgabe, nämlich die Schaffung einer Wärmebehandlungsanlage zur Durchführung des erfindungsgemäßen Verfahrens wird dadurch gelöst, dass der Wärmetauscher zum zumindest teilweisen Auffüllen mit dem flüssigen Kältemittel ausgebildet ist und dass die Kühlkapazi-tät des Wärmetauschers aufgrund des Verdampfens der Einfüllmenge beim Umwälzen des Abschreckgases zum vollständigen Kühlen einer Charge von Werkstücken bemessen ist.The second task, namely the creation of a heat treatment system for carrying out the method according to the invention is achieved in that the heat exchanger is designed to be at least partially filled with the liquid refrigerant and that the cooling capacity of the heat exchanger is completely due to the evaporation of the filling quantity when the quenching gas is circulated Cooling of a batch of workpieces is dimensioned.
Eine solche Wärmebehandlungsanlage ist sehr kostengünstig zu erstellen, weil sie kein Kälteaggregat mit einem Verflüssiger und mit einem Verdichter für das Kältemittel benötigt. Weiterhin vermag sie das Abschreckgas besonders wirksam abzukühlen, weil während des Zirkulierens des Abschreckgases das Kältemittel in dem Wärmetauscher verdampft und deshalb dem Abschreckgas durch die von dem Kältemittel aufgenommene Verdampfungswärme viel Wärme entzogen wird. Der Wärmetauscher selbst braucht gegenüber den bisher verwendeten, mit einer Sole betriebenen Wärmetauschern nicht oder nur geringfügig umgestaltet zu werden.Such a heat treatment system is very inexpensive to build because it does not require a refrigeration unit with a condenser and with a compressor for the refrigerant. Furthermore, it is able to cool the quenching gas particularly effectively because the refrigerant evaporates in the heat exchanger during the circulation of the quenching gas and therefore much heat is extracted from the quenching gas by the heat of vaporization absorbed by the refrigerant. The heat exchanger itself does not need to be redesigned, or only slightly, in comparison with the heat exchangers used with brine.
Die zur Kühlung des Abschreckgases erforderliche Kältemittelmenge kann besonders gering sein, wenn der Wärmetauscher mit Wärmetauscherflächen von hohem Wärmespeichervermögen ausgestattet ist.The amount of refrigerant required to cool the quenching gas can be particularly low if the heat exchanger is equipped with heat exchanger surfaces with high heat storage capacity.
Eine gegenseitige Isolation des Wärmetauschers und des Ofenbereiches durch thermisch isolierte Trennwände wird wegen des in der Behandlungskammer während des Aufheizens der Werkstücke aufgrund des in der Behandlungskammer herrschenden Vakuums unnötig. Deshalb ist es möglich, dass die Behandlungskammer in einem gemeinsamen Gehäuse einen Ofenbereich und den Wärmetauscher aufweist.Mutual insulation of the heat exchanger and the furnace area by thermally insulated partition walls becomes unnecessary because of the vacuum in the treatment chamber during the heating of the workpieces due to the vacuum in the treatment chamber. It is therefore possible that the treatment chamber has a furnace area and the heat exchanger in a common housing.
Das verdampfte Kältemittel kann einer weiteren Verwendung zugeführt werden, wenn ein Gassammelbehälter für das in dem Wärmetauscher verdampfte Kältemittel vorgesehen ist.The evaporated refrigerant can be used for a further purpose if a gas collection container is provided for the refrigerant evaporated in the heat exchanger.
Die erfindungsgemäße Wärmebehandlungsanlage benötigt zu ihrem Betrieb eine ganz besonders geringe Kältemittelmenge, wenn gemäß einer anderen Weiterbildung der Erfindung in der Behandlungskammer hintereinander zwei Wärmetauscher geschaltet sind und wenn nur ein Wärmetauscher als Verdampfer für das Kältemittel ausgebildet ist, während der andere Wärmetauscher zum Zirkulieren eines Kältemittels oder Wasser oder Wärmeträgers mit einem externen Kühlmittelaggregat verbunden ist.The heat treatment system according to the invention requires a very particularly small amount of refrigerant to operate if, according to another development of the invention, two heat exchangers are connected in series in the treatment chamber and if only one heat exchanger is designed as an evaporator for the refrigerant, while the other heat exchanger is used to circulate a refrigerant or Water or heat transfer medium is connected to an external coolant unit.
Die Erfindung lässt zahlreiche Ausführungsformen zu. Zur weiteren Verdeutlichung ihres Grundprinzips ist in der Zeichnung schematisch eine Wärmebehandlungsanlage dargestellt und wird nachfolgend beschrieben.The invention permits numerous embodiments. To further clarify its basic principle is in the Drawing schematically shows a heat treatment system and is described below.
Die Zeichnung zeigt eine Behandlungskammer 1, welche in einem gemeinsamen Gehäuse 2 einen Wärmetauscher 3 und einen Ofenbereich 4 hat, in welchem sich eine Charge 5 mit den zu behandelnden Werkstücken befindet. Hinter dem Wärmetauscher 3 ist ein Gebläse 6 angeordnet, durch welches es möglich wird, ein Abschreckgas innerhalb der Behandlungskammer 1 durch die Charge 5 und den Wärmetauscher 3 hindurch zirkulieren zu lassen.The drawing shows a treatment chamber 1, which has a heat exchanger 3 and a furnace area 4 in a common housing 2, in which there is a batch 5 with the workpieces to be treated. A fan 6 is arranged behind the heat exchanger 3, by means of which a quenching gas can be circulated within the treatment chamber 1 through the charge 5 and the heat exchanger 3.
Die Zeichnung zeigt weiterhin einen Vorratsbehälter 7 für flüssigen Stickstoff. Aus diesem Vorratsbehälter 7 füllt man eine kleinere Stickstoffmenge in einen Zwischenbehälter 8, von dein aus flüssiger Stickstoff durch Öffnen eines Ventils 9 in den Wärmetauscher 3 eingefüllt werden kann. Im Wärmetauscher 3 verdampfter Stickstoff vermag über eine Leitung 10 in einen Gassammelbehälter 11 zu gelangen. Über eine Leitung 12, in der ein Ventil 13 geschaltet ist, kann der Zwischenbehälter 8 mit dem Druck des Gassammelbehälters 11 beaufschlagt werden, um flüssigen Stickstoff aus dem Zwischenbehälter 8 in den Wärmetauscher 3 zu drücken. Der im Wärmetauscher 3 verdampfte Stickstoff gelangt über eine Rückschlagklappe 14 in die Leitung 10 und dadurch in den Gassammelbehälter 11. Bei zu hohen Drücken lässt ein Überdruckventil 15 Stickstoff in die Atmosphäre abströmen. Zum Fluten der Behandlungskammer 1 mit Stickstoff aus dem Gassammelbehälter 11 ist die Leitung 10 über ein Ventil 16 mit der Behandlungskammer 1 verbunden.The drawing also shows a storage container 7 for liquid nitrogen. From this storage container 7, a smaller amount of nitrogen is filled into an intermediate container 8, from which liquid nitrogen can be filled into the heat exchanger 3 by opening a valve 9. Nitrogen evaporated in the heat exchanger 3 is able to reach a gas collecting container 11 via a line 10. Via a line 12 in which a
Die Wärmebehandlung einer Charge 5 erfolgt unter Vakuum, indem die Charge 5 zunächst auf beispielsweise 1000°C aufgewärmt wird. Während dieser Aufwärmphase befüllt man den Wärmetauscher 3 mit flüssigem Stickstoff aus dem Zwischenbehälter 8. Soll die Abschreckphase beginnen, dann flutet man die Behandlungskammer 1 durch Öffnen des Ventils 16 mit gasförmigem Stickstoff als Abschreckgas und schaltet das Gebläse 6 an. Dadurch zirkuliert in der Behandlungskammer 1 zwischen der Charge 5 und durch den Wärmetauscher 3 das Abschreckgas. Da dieses der Charge 5 Wärme entnimmt und sich dadurch aufwärmt, kommt es beim Durchströmen des Wärmetauschers 3 zu einem Verdampfen des in ihm zuvor eingefüllten flüssigen Stickstoffs und dadurch zu einem Wärmeentzug bei dem Abschreckgas. Der verdampfte Stickstoff vermag über die Rückschlagklappe 14 und die Leitung 10 in den Gassammelbehälter 11 zu gelangen. Ein Überströmventil 17 ermöglicht es, das bei einem zu hohen Druck im Wärmetauscher 3 (z.B. über 6 bar) Gas aus dem Wärmetauscher 3 in die Behandlungskammer 1 strömt.The heat treatment of a batch 5 is carried out under vacuum by first heating the batch 5 to, for example, 1000 ° C. During this warm-up phase, the heat exchanger 3 is filled with liquid nitrogen from the intermediate container 8. If the quenching phase is to begin, the treatment chamber 1 is flooded by opening the valve 16 with gaseous nitrogen as the quenching gas and the fan 6 is switched on. As a result, the quenching gas circulates in the treatment chamber 1 between the charge 5 and through the heat exchanger 3. Since this takes heat from the charge 5 and thereby heats up, when the heat exchanger 3 flows through it, the liquid nitrogen previously filled in it evaporates and, as a result, heat is removed from the quenching gas. The evaporated nitrogen is able to reach the gas collection container 11 via the check valve 14 and the line 10. An
Es sei abschließend bemerkt, dass das erfindungsgemäße verfahren auch bei Anlagen möglich ist, bei denen das Aufheizen der Charge 5 und das Abschrecken mit dem Abschreckgas in getrennten Kammern erfolgt. Wesentlich für das erfindungsgemäße Verfahren ist lediglich, dass während des Einkühlens des Wärmetauschers in der ihn aufnehmenden Kammer Vakuum herrscht, damit der Wärmetauscher erst wirkungsvoll zu arbeiten beginnt, wenn die Charge mittels des Abschreckgases gekühlt werden soll.It should finally be noted that the method according to the invention is also possible in systems in which the batch 5 is heated and quenched with the quenching gas in separate chambers. It is only essential for the method according to the invention that a vacuum prevails in the chamber receiving it during the cooling of the heat exchanger, so that the heat exchanger only begins to work effectively when the batch is to be cooled by means of the quenching gas.
Das erfindungsgemäße Verfahren erlaubt auch ein Rückverflüssigung des verdampften Gases in einer Kompressoranlage. Die Ansprüche an die Reinheit und Qualität des verdampfenden Gases (Kühlmittels) sind gering. Der Wärmetauscher funktioniert auch in nicht evakuierten Kammern.The method according to the invention also allows the vaporized gas to be reliquefied in a compressor system. The demands on the purity and quality of the evaporating gas (coolant) are low. The heat exchanger also works in non-evacuated chambers.
- 11
- BehandlungskammerTreatment chamber
- 22nd
- Gehäusecasing
- 33rd
- WärmetauscherHeat exchanger
- 44th
- OfenbereichFurnace area
- 55
- ChargeBatch
- 66
- Gebläsefan
- 77
- VorratsbehälterStorage container
- 88th
- ZwischenbehälterIntermediate container
- 99
- VentilValve
- 1010th
- Leitungmanagement
- 1111
- GassammelbehälterGas collection container
- 1212th
- Leitungmanagement
- 1313
- VentilValve
- 1414
- RückschlagklappeCheck valve
- 1515
- ÜberdruckventilPressure relief valve
- 1616
- VentilValve
- 1717th
- ÜberströmventilOverflow valve
Claims (12)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19820083 | 1998-05-06 | ||
| DE19820083A DE19820083A1 (en) | 1998-05-06 | 1998-05-06 | Process for quenching workpieces and heat treatment system for carrying out the process |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0955384A2 true EP0955384A2 (en) | 1999-11-10 |
| EP0955384A3 EP0955384A3 (en) | 2000-01-19 |
| EP0955384B1 EP0955384B1 (en) | 2005-04-13 |
Family
ID=7866757
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP99104318A Expired - Lifetime EP0955384B1 (en) | 1998-05-06 | 1999-03-04 | Process for quenching workpieces with gases and heat treating installation for carrying out said process |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0955384B1 (en) |
| DE (2) | DE19820083A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2835907A1 (en) * | 2002-02-12 | 2003-08-15 | Air Liquide | GAS QUENCHING PLANT AND CORRESPONDING QUENCHING METHOD |
| WO2007048664A1 (en) * | 2005-10-27 | 2007-05-03 | Robert Bosch Gmbh | Method and installation for the dry transformation of a material structure of semifinished products |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10054765A1 (en) * | 2000-11-04 | 2002-05-16 | Messer Griesheim Gmbh | Heat treatment furnace used for heat treating steel comprises a housing containing a heating chamber with a treatment chamber having a deep cooling system |
| US8820098B2 (en) | 2011-05-17 | 2014-09-02 | Air Products And Chemicals, Inc. | Method and apparatus for quenching of materials in vacuum furnace |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1452062A (en) * | 1972-10-10 | 1976-10-06 | Boc International Ltd | Metal treatment |
| WO1991009976A1 (en) * | 1989-12-21 | 1991-07-11 | Cambridge Vacuum Engineering Ltd. | Apparatus and method for cooling a furnace load |
| DE4422588C1 (en) * | 1994-06-28 | 1995-06-22 | Leybold Durferrit Gmbh | Gas quenching device in a heat treatment apparatus |
| DE19628383A1 (en) * | 1995-07-21 | 1997-02-06 | Ipsen Ind Int Gmbh | Furnace for heat treatment of batches of metal workpieces - with a heating chamber which can be isolated from the pressure and suction chambers of the cooling gas fan |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3346884A1 (en) * | 1983-12-23 | 1985-07-11 | Ipsen Industries International Gmbh, 4190 Kleve | INDUSTRIAL STOVES FOR HEAT TREATMENT OF METAL WORKPIECES |
| DE3501463A1 (en) * | 1985-01-17 | 1986-07-17 | Linde Ag, 6200 Wiesbaden | METHOD AND DEVICE FOR HEAT TREATMENT OF WORKPIECES |
| DE4435862C1 (en) * | 1994-10-07 | 1995-08-24 | Leybold Durferrit Gmbh | Method and appts. for cooling, esp. for quenching workpieces by gases |
-
1998
- 1998-05-06 DE DE19820083A patent/DE19820083A1/en not_active Ceased
-
1999
- 1999-03-04 EP EP99104318A patent/EP0955384B1/en not_active Expired - Lifetime
- 1999-03-04 DE DE59911888T patent/DE59911888D1/en not_active Expired - Lifetime
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1452062A (en) * | 1972-10-10 | 1976-10-06 | Boc International Ltd | Metal treatment |
| WO1991009976A1 (en) * | 1989-12-21 | 1991-07-11 | Cambridge Vacuum Engineering Ltd. | Apparatus and method for cooling a furnace load |
| DE4422588C1 (en) * | 1994-06-28 | 1995-06-22 | Leybold Durferrit Gmbh | Gas quenching device in a heat treatment apparatus |
| DE19628383A1 (en) * | 1995-07-21 | 1997-02-06 | Ipsen Ind Int Gmbh | Furnace for heat treatment of batches of metal workpieces - with a heating chamber which can be isolated from the pressure and suction chambers of the cooling gas fan |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2835907A1 (en) * | 2002-02-12 | 2003-08-15 | Air Liquide | GAS QUENCHING PLANT AND CORRESPONDING QUENCHING METHOD |
| WO2003068998A1 (en) * | 2002-02-12 | 2003-08-21 | L'air Liquide, Societe Anonyme A Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes Georges Claude | Gas quenching installation and the corresponding quenching method |
| WO2007048664A1 (en) * | 2005-10-27 | 2007-05-03 | Robert Bosch Gmbh | Method and installation for the dry transformation of a material structure of semifinished products |
| US8715566B2 (en) | 2005-10-27 | 2014-05-06 | Robert Bosch Gmbh | Method and installation for the dry transformation of a material structure of semifinished products |
Also Published As
| Publication number | Publication date |
|---|---|
| DE59911888D1 (en) | 2005-05-19 |
| DE19820083A1 (en) | 1999-11-11 |
| EP0955384A3 (en) | 2000-01-19 |
| EP0955384B1 (en) | 2005-04-13 |
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