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EP0643223A1 - Method and arrangement for sealing a shaft passage in gear pumps - Google Patents

Method and arrangement for sealing a shaft passage in gear pumps Download PDF

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Publication number
EP0643223A1
EP0643223A1 EP93111510A EP93111510A EP0643223A1 EP 0643223 A1 EP0643223 A1 EP 0643223A1 EP 93111510 A EP93111510 A EP 93111510A EP 93111510 A EP93111510 A EP 93111510A EP 0643223 A1 EP0643223 A1 EP 0643223A1
Authority
EP
European Patent Office
Prior art keywords
shaft
sealing
medium
seal
space
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP93111510A
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German (de)
French (fr)
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EP0643223B1 (en
Inventor
Roger Stehr
Martin Schaich
Eduard Mischler
Christian Schmid
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Maag Pump Systems AG
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Maag Pump Systems AG
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Filing date
Publication date
Application filed by Maag Pump Systems AG filed Critical Maag Pump Systems AG
Priority to AT93111510T priority Critical patent/ATE163074T1/en
Priority to EP93111510A priority patent/EP0643223B1/en
Priority to DE59308121T priority patent/DE59308121D1/en
Publication of EP0643223A1 publication Critical patent/EP0643223A1/en
Application granted granted Critical
Publication of EP0643223B1 publication Critical patent/EP0643223B1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
    • F04C15/0003—Sealing arrangements in rotary-piston machines or pumps
    • F04C15/0034—Sealing arrangements in rotary-piston machines or pumps for other than the working fluid, i.e. the sealing arrangements are not between working chambers of the machine
    • F04C15/0038—Shaft sealings specially adapted for rotary-piston machines or pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C13/00—Adaptations of machines or pumps for special use, e.g. for extremely high pressures
    • F04C13/001—Pumps for particular liquids
    • F04C13/002—Pumps for particular liquids for homogeneous viscous liquids

Definitions

  • the present invention relates to a method according to the preamble of claim 1, a sealed shaft bushing according to that of claim 2 and a gear pump according to claim 7.
  • DE-OS-41 25 describes a method for sealing a shaft bushing in a medium-filled space, in which the pressure adjusts as a function of the shaft speed and the medium is a Newtonian or non-Newtonian liquid whose viscosity is temperature-dependent 128 known. It describes a gear pump shaft bushing.
  • the aim is to prevent ambient air from entering the pump delivery chamber, both under operating and at standstill conditions.
  • a pumped-up leakage absorption zone is provided for the return of the pumped medium, which is designed as an annular chamber can be emptied into the environment through a lockable outlet.
  • a subsequently provided labyrinth seal with a thread conveying direction acting against the leakage space starts from an intermediate annular chamber, to which a labyrinth seal, which conveys the opposite, is connected, which finally opens into another collecting space, which can be emptied to the outside. This is followed by the grease supply seal or the sealing liquid seal.
  • a gear pump with the mentioned shaft seal according to the invention is distinguished by the wording of claim 7.
  • the present invention is based on the knowledge that the sealing mechanisms for the operating states “rotating shaft” and “standstill” are to be separated and that, as will be explained below, the viscosity behavior of the medium present on one side of the bushing can be optimally used for this purpose.
  • FIG. 1 schematically shows a passage of a shaft 1 from a first space U into a second M, in which the latter is a Newtonian or non-Newtonian liquid.
  • the space M corresponds to the axially outer plain bearing gap before the seal begins.
  • the pressure p in the medium in space M depends on the speed n of the shaft and the viscosity ⁇ of this medium is known to depend on the temperature ⁇ .
  • a sealing stage 3 is first provided according to the invention, the sealing effect of which depends on the speed n of the shaft 1.
  • a sealing liquid seal 7 is provided on a further sealing step 5 to ensure the gas tightness of the seal. Their effect is independent of the wave operation. In general, however, it must be ensured that no pumped medium from stage 3 reaches the area of the sealing liquid seal 7 and renders it ineffective. This is not initially ensured when the shaft is at a standstill, because sealing stage 3 is only effective to a significantly reduced extent.
  • the barrier liquid S is now also used as a cooling medium for the adjacent area of the shaft 1 and the sealing stage 3, which increases the viscosity ⁇ of the medium located in stage 3, particularly when the shaft is at a standstill, which increases the necessary sealing effect at the stage 3 is ensured despite the shaft being at a standstill.
  • FIG. 2 shows a simplified sectional illustration of a shaft bushing according to the invention working according to the method according to the invention, in particular on a gear pump for polymer melts.
  • a labyrinth seal 17 is then provided, preferably with a thread 17a provided on the housing side, which, in the given direction of rotation of the shaft 1, which must not be inverted, conveys towards the space M, depending on the speed. as shown with F.
  • the conveying labyrinth seal 17 acts as the sealing step 3 explained with reference to FIG. 1.
  • the sealing liquid sealing step 7 is then provided axially, as has been explained.
  • a ring 19 secured against rotation on the housing side which on the one hand abuts the shaft 1 with an annular sealing chamber 21 and is connected to the outer ring periphery via at least two radially opposite bores 25 with radially outer widenings 23.
  • the widenings 23 communicate with at least one inlet line 27 for barrier liquid S and one outlet line 29.
  • Sealing elements preferably spring-loaded (not shown) stuffing box packings or lip seal arrangements 31, are provided axially on both sides of the ring 19 in corresponding recesses on the housing side.
  • the axial extent of the Widenings 23 ensure that axial displacements of the ring 19 are absorbed without impeding the flow of sealing liquid S, due to the setting of the spring-loaded gland packing.
  • the labyrinth seal and barrier liquid stage 7 are arranged in an interchangeable sleeve 33, which can be connected in a simple manner to the housing 15, through which is carried out, as can be screwed.
  • the proposed shaft bushing is extremely easy to service, and all periodic emptying of any leak zones and collecting spaces provided is eliminated.
  • the cooling also ensures that the operating temperatures in the area of the sealing elements 31, be they stuffing box packings or lip seals, do not exceed the temperatures prescribed for this.
  • the cooling effect must be ensured in such a way that, even when the shaft is at a standstill, against the operating pressure is sealed in space M, which decelerates with a time delay after shaft 1 has stopped.
  • the cooling effect can be adapted to the requirements of the respective product through the temperature, the volume flow, the heat capacity and the thermal coupling of the barrier medium.
  • the entry of gas into the room M can be prevented even if the ambient pressure is higher than atmospheric pressure.
  • Circulation of the sealing and, according to the invention, cooling liquid can preferably be carried out by utilizing the thermosiphon effect or by using a specially designed circulating element.
  • An external pump can be provided as the circulating element, or the shaft in the sealing chamber 21 can be designed such that it itself acts as a circulating element.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Rotary Pumps (AREA)
  • Sealing Using Fluids, Sealing Without Contact, And Removal Of Oil (AREA)

Abstract

For gear pumps in particular, a shaft gland is proposed which, as seen from the plain bearing (journal, sleeve bearing) annulus or a relief chamber (M), is equipped firstly with a labyrinth seal (17) having a screw conveying direction directed towards the chamber (M) and then a sealing-fluid sealing stage (7). To ensure the sealing effect, the circulated sealing fluid (S) serves as a cooling medium (coolant) for those zones of the labyrinth seal (17), which are situated on the external side of the shaft. <IMAGE>

Description

Die vorliegende Erfindung betrifft ein Verfahren nach dem Oberbegriff von Anspruch 1, eine dichte Wellendurchführung nach demjenigen von Anspruch 2 und eine Zahnradpumpe nach Anspruch 7.The present invention relates to a method according to the preamble of claim 1, a sealed shaft bushing according to that of claim 2 and a gear pump according to claim 7.

Ein Verfahren zum Dichten einer Wellendurchführung in einen mediumsgefüllten Raum, worin sich der Druck in Funktion der Wellendrehzahl einstellt und wobei das Medium eine Newton'sche oder nicht Newton'sche Flüssigkeit ist, deren Viskosität temperaturabhängig ist, ist aus der DE-OS-41 25 128 bekannt. Darin ist eine Zahnradpumpen-Wellendurchführung beschrieben. Insbesondere für die Förderung von Polymerschmelzen vorgesehen, soll einerseits verhindert werden, dass Umgebungsluft in den Förderraum der Pumpe eindringt, und zwar sowohl unter Betriebs- wie auch unter Stillstandsbedingungen.DE-OS-41 25 describes a method for sealing a shaft bushing in a medium-filled space, in which the pressure adjusts as a function of the shaft speed and the medium is a Newtonian or non-Newtonian liquid whose viscosity is temperature-dependent 128 known. It describes a gear pump shaft bushing. Provided in particular for the conveyance of polymer melts, on the one hand, the aim is to prevent ambient air from entering the pump delivery chamber, both under operating and at standstill conditions.

Um weiter zu verhindern, dass Fördermedium in eine zu obgenanntem Zwecke vorgesehene Sperrflüssigkeits- oder Fettvorlagedichtung eindringt, wird, ausgehend vom Entlastungsraum, in welchen Fördermedium axial eindringt und der mit dem Pumpeneinlass verbunden ist, zur Rückführung aufgenommenen Fördermediums eine als Ringkammer ausgebildete Leckaufnahmezone vorgesehen, die durch einen verschliessbaren Auslass in die Umgebung entleert werden kann. Eine anschliessend vorgesehene Labyrinthdichtung mit gegen den Leckraum wirkender Gewindeförderrichtung geht aus von einer Zwischen-Ringkammer, an welche eine umgekehrt fördernde Labyrinthdichtung anschliesst, die schliesslich in einen weiteren Sammelraum, nach aussen entleerbar, ausmündet. Anschliessend folgt die Fettvorlagedichtung oder die Sperrflüssigkeitsdichtung.In order to further prevent the pumped medium from penetrating into a sealing liquid or grease supply seal provided for the above-mentioned purpose, starting from the relief space, into which pumped medium penetrates axially and which is connected to the pump inlet, a pumped-up leakage absorption zone is provided for the return of the pumped medium, which is designed as an annular chamber can be emptied into the environment through a lockable outlet. A subsequently provided labyrinth seal with a thread conveying direction acting against the leakage space starts from an intermediate annular chamber, to which a labyrinth seal, which conveys the opposite, is connected, which finally opens into another collecting space, which can be emptied to the outside. This is followed by the grease supply seal or the sealing liquid seal.

Weil die mit den fördernden Labyrinthdichtungen realisierten Dichtungen bei Wellenstillstand unwirksam werden, wird eine gegenseitige Kontamination von Fördermedium und Fettvorlagenmedium bzw. der Sperrflüssigkeit` durch das Vorsehen von Leckzonen und Sammelzonen, die nach aussen entleerbar sind bzw. mit dem Pumpeneinlass verbunden sind, vermieden.Because the seals made with the conveying labyrinth seals become ineffective when the shaft comes to a standstill, mutual contamination of the pumped medium and the grease medium or the sealing liquid is avoided by providing leak zones and collecting zones that can be emptied to the outside or are connected to the pump inlet.

Die hier vorgeschlagene Lösung ist äusserst kompliziert und baut eigentlich auf der axialen Serieschaltung von Dichtungen mit Sammelkammern auf, welche eine zunehmende Dichtsicherheit ergeben, aber mit, wie erwähnt, grossem Aufwand.The solution proposed here is extremely complicated and actually builds on the axial series connection of seals with collecting chambers, which result in increasing sealing reliability, but, as mentioned, with great effort.

Es ist Aufgabe der vorliegenden Erfindung, ein Verfahren bzw. eine Wellendichtung eingangs genannter Art zu schaffen, die konstruktiv wesentlich einfacher ist und bei der ein periodisches Entleeren von Sammelzonen entfällt.It is an object of the present invention to provide a method or a shaft seal of the type mentioned at the outset, which is structurally much simpler and in which periodic emptying of collecting zones is dispensed with.

Dies wird beim Verfahren eingangs genannter Art durch Vorgehen nach dem kennzeichnenden Teil von Anspruch 1 erreicht bzw. bei einer dichten Wellendurchführung bei deren Ausbildung nach dem kennzeichnenden Teil von Anspruch 2.This is achieved in the method of the type mentioned at the outset by proceeding according to the characterizing part of claim 1 or in the case of a dense shaft bushing when it is formed according to the characterizing part of claim 2.

Bevorzugte Ausführungsvarianten der Wellendurchführung sind in den Ansprüchen 3 bis 6 spezifiziert.Preferred variants of the shaft bushing are specified in claims 3 to 6.

Eine Zahnradpumpe mit der erwähnten erfindungsgemässen Wellendichtung zeichnet sich nach dem Wortlaut von Anspruch 7 aus.A gear pump with the mentioned shaft seal according to the invention is distinguished by the wording of claim 7.

Die Erfindung wird anschliessend beispielsweise anhand von Figuren erläutert.The invention is subsequently explained, for example, using figures.

Es zeigen:

Fig. 1
anhand einer schematischen Darstellung einer Wellendurchführung, das erfindungsgemässe Vorgehen verfahrensmässig bzw. die Grundstruktur einer erfindungsgemässen Wellendurchführung;
Fig. 2
in vereinfachter Längsschnittdarstellung eine erfindungsgemässe Wellendurchführung, beispielsweise und insbesondere für die Durchführung einer Zahnradpumpenwelle.
Show it:
Fig. 1
based on a schematic representation of a shaft bushing, the procedure according to the invention in terms of method or the basic structure of a shaft bushing according to the invention;
Fig. 2
in a simplified longitudinal sectional view of a shaft bushing according to the invention, for example and in particular for the implementation of a gear pump shaft.

Die vorliegende Erfindung geht von der Erkenntnis aus, dass die Abdichtmechanismen für die Betriebszustände "drehende Welle" und "Stillstand" zu trennen sind und dass, wie nachfolgend erläutert werden soll, das Viskositätsverhalten des einseitig der Durchführung vorliegenden Mediums hierzu optimal ausgenützt werden kann.The present invention is based on the knowledge that the sealing mechanisms for the operating states "rotating shaft" and "standstill" are to be separated and that, as will be explained below, the viscosity behavior of the medium present on one side of the bushing can be optimally used for this purpose.

In Fig. 1 ist schematisch eine Durchführung einer Welle 1 von einem ersten Raum U in einen zweiten M dargestellt, in welch letzterem eine Newton'sche oder nicht Newton'sche Flüssigkeit ist. Bei einer Zahnradpumpe mit Gleitlager entspricht der Raum M dem axial äusseren Gleitlagerspalt vor Dichtungsbeginn. Wie insbesondere auch bei einer Pumpe, dabei insbesondere einer Zahnradpumpe, ist der Druck p in dem im Raum M vorliegenden Medium abhängig von der Drehzahl n der Welle und die Viskosität η dieses Mediums bekanntermassen abhängig von der Temperatur ϑ.1 schematically shows a passage of a shaft 1 from a first space U into a second M, in which the latter is a Newtonian or non-Newtonian liquid. In the case of a gear pump with a plain bearing, the space M corresponds to the axially outer plain bearing gap before the seal begins. As is also the case with a pump, in particular a gear pump, the pressure p in the medium in space M depends on the speed n of the shaft and the viscosity η of this medium is known to depend on the temperature ϑ.

Ausgehend vom mediumbeschickten Raum M, wird erfindungsgemäss erst eine Dichtungsstufe 3 vorgesehen, deren Dichtwirkung abhängig ist von der Drehzahl n der Welle 1. Mithin ist der durch die Dichtwirkung maximal gedichtete axiale Druckunterschied Δp abhängig sowohl von der Drehzahl n der Welle 1 wie auch von der Viskosität η des Mediums im Dichtspalt der Stufe 3. Steht die Welle still, d.h. bei n = 0, bleibt die Dichtwirkung an Stufe 3 nurmehr von der Viskosität η des Mediums im Dichtraum der Stufe 3 abhängig.Starting from the medium-charged space M, a sealing stage 3 is first provided according to the invention, the sealing effect of which depends on the speed n of the shaft 1. The maximum axial pressure difference Δp sealed by the sealing effect is dependent both on the speed n of the shaft 1 and on the Viscosity η of the medium in the sealing gap of stage 3. If the shaft stands still, ie if n = 0, it remains Sealing effect at level 3 depends only on the viscosity η of the medium in the level 3 sealing chamber.

Nach aussen fortschreitend, ist zur Sicherstellung der Gasdichtheit der Dichtung an einer weiteren Dichtstufe 5 eine Sperrflüssigkeitsdichtung 7 vorgesehen. Ihre Wirkung ist vom Wellenbetrieb unabhängig. Es muss aber im allgemeinen sichergestellt sein, dass kein Fördermedium aus der Stufe 3 in den Bereich der Sperrflüssigkeitsdichtung 7 gelangt und diese unwirksam macht. Im Wellenstillstand ist dies vorerst nicht sichergestellt, weil die Dichtungsstufe 3 nur in wesentlich reduziertem Umfange wirksam ist.Progressing outwards, a sealing liquid seal 7 is provided on a further sealing step 5 to ensure the gas tightness of the seal. Their effect is independent of the wave operation. In general, however, it must be ensured that no pumped medium from stage 3 reaches the area of the sealing liquid seal 7 and renders it ineffective. This is not initially ensured when the shaft is at a standstill, because sealing stage 3 is only effective to a significantly reduced extent.

Erfindungsgemäss wird nun aber die Sperrflüssigkeit S auch als Kühlmedium für den angrenzenden Bereich der Welle 1 und der Dichtungsstufe 3 eingesetzt, womit dort kühlungsbedingt die Viskosität η des insbesondere bei Stillstand der Welle in der Stufe 3 befindlichen Mediums erhöht wird, womit die notwendige Dichtwirkung an Stufe 3 trotz Wellenstillstands sichergestellt ist.According to the invention, however, the barrier liquid S is now also used as a cooling medium for the adjacent area of the shaft 1 and the sealing stage 3, which increases the viscosity η of the medium located in stage 3, particularly when the shaft is at a standstill, which increases the necessary sealing effect at the stage 3 is ensured despite the shaft being at a standstill.

Mit Blick auf Pumpen, beispielsweise mit Antriebswelle 1 und dabei insbesondere auf Zahnradpumpen als bevorzugtes Einsatzgebiet für das erfindungsgemässe Verfahren bzw. die erfindungsgemässe Wellendurchführung, insbesondere auf Zahnradpumpen zur Förderung von Polymerschmelzen, ist erkenntlich, dass bei stillstehender Welle 1 der Druck im Raum vor der Stufe 3 wesentlich geringer wird als im Normalbetrieb der Pumpe. Dies verringert zusätzlich die nach erreichtem Stillstand notwendigen zusätzlichen Dichtmassnahmen durch Viskositätsausnützung, da mithin die leckagetreibende Kraft abnimmt. Mit Q̇ ist schematisch die Wärmeabfuhr mittels der Sperrflüssigkeit dargestellt. Die Sperrflüssigkeit kann durch Thermosiphonwirkung und/oder durch eigens dafür vorgesehene Umwälzorgane, wie durch ein Förderaggregat 9, oder durch wellenintegrierte Förderorgane an der Dichtung 7 umgewälzt werden.With regard to pumps, for example with drive shaft 1 and in particular gear pumps as a preferred area of application for the method according to the invention or the shaft bushing according to the invention, in particular gear pumps for conveying polymer melts, it can be seen that when the shaft 1 is stationary, the pressure in the space in front of the step 3 becomes significantly lower than in normal operation of the pump. This additionally reduces the additional sealing measures required after the standstill has been achieved by utilizing the viscosity, since the leak-driving force consequently decreases. With Q̇ the heat dissipation by means of the barrier liquid is shown schematically. The barrier liquid can by thermosiphon effect and / or by means of specially provided circulating elements, such as be circulated by a conveyor unit 9, or by shaft-integrated conveyor elements on the seal 7.

In Fig. 2 ist in vereinfachter Schnittdarstellung eine nach dem erfindungsgemässen Verfahren arbeitende erfindungsgemässe Wellendurchführung, insbesondere an einer Zahnradpumpe für Polymerschmelzen, dargestellt.2 shows a simplified sectional illustration of a shaft bushing according to the invention working according to the method according to the invention, in particular on a gear pump for polymer melts.

Die Welle 1 mit Lagerblock 11, zahnradseitig, definiert den Lagerspaltraum, an den, in bekannter Weise, ein Entlastungsraum 13 anschliesst, mit der Saugseite der Pumpe verbunden (nicht dargestellt). Dieser bildet hier den Raum M gemäss Fig. 1. Daran anschliessend ist eine Labyrinthdichtung 17 vorgesehen, vorzugsweise mit gehäuseseitig vorgesehenem Gewinde 17a, welches bei der vorgegebenen Drehrichtung der Welle 1, die nicht invertiert werden darf, gegen den Raum M hin fördert, drehzahlabhängig, wie mit F dargestellt. Die fördernde Labyrinthdichtung 17 wirkt als die anhand von Fig. 1 erläuterte Dichtungsstufe 3. Axial anschliessend ist, wie erläutert wurde, die Sperrflüssigkeits-Dichtstufe 7 vorgesehen.The shaft 1 with the bearing block 11, on the gear wheel side, defines the bearing gap space, to which, in a known manner, a relief space 13 connects, is connected to the suction side of the pump (not shown). 1. This forms the space M according to FIG. 1. A labyrinth seal 17 is then provided, preferably with a thread 17a provided on the housing side, which, in the given direction of rotation of the shaft 1, which must not be inverted, conveys towards the space M, depending on the speed. as shown with F. The conveying labyrinth seal 17 acts as the sealing step 3 explained with reference to FIG. 1. The sealing liquid sealing step 7 is then provided axially, as has been explained.

In bevorzugter Art und Weise umfasst sie einen gehäuseseitig verdrehfest gesicherten Ring 19, der einerseits mit einer Ringdichtkammer 21 an der Welle 1 anliegt und über mindestens zwei sich radial gegenüberliegende Bohrungen 25 mit radial aussenseitigen Aufweitungen 23 mit der äusseren Ringperipherie verbunden ist. Gehäuseseitig kommunizieren die Aufweitungen 23 mit mindestens einer Einlassleitung 27 für Sperrflüssigkeit S und einer Auslassleitung 29.In a preferred manner, it comprises a ring 19 secured against rotation on the housing side, which on the one hand abuts the shaft 1 with an annular sealing chamber 21 and is connected to the outer ring periphery via at least two radially opposite bores 25 with radially outer widenings 23. On the housing side, the widenings 23 communicate with at least one inlet line 27 for barrier liquid S and one outlet line 29.

Dichtelemente, bevorzugterweise federvorgespannte (nicht dargestellt) Stopfbuchspackungen oder Lippendichtungsanordnungen 31, sind axial beidseitig des Ringes 19 in entsprechenden Einformungen gehäuseseitig vorgesehen. Die Axialausdehnung der Aufweitungen 23 sichert dabei, dass axiale Verschiebungen des Ringes 19, ohne den Durchfluss von Sperrflüssigkeit S zu behindern, aufgenommen werden, bedingt durch sich Setzen der federkraftbelasteten Stopfbuchspackungen. Durch Wahl der Sperrflüssigkeit S mit entsprechender Wärmekapazität, deren Fluss durch die Stufe 7 und der thermischen Leitfähigkeit zwischen axial aussenliegendem Bereich der Stufe 3 und den Fliesswegen der Sperrflüssigkeit S wird die Kühlung in besagtem Bereich der Stufe 3, d.h. in Fig. 2, dem axial aussenliegenden Bereich der Labyrinthdichtung, so sichergestellt, dass bei Stillstand der Welle 1, beispielsweise bei einer schmelzefördernden Zahnradpumpe, unter Berücksichtigung des Druckabfalles im Lagerspalt und gegebenenfalls im Entlastungsraum, M, und der Viskositatszunahme von Fördermedium im axial aussenliegenden Labyrinthdichtungsbereich die notwendige Dichtheit zwischen genanntem Raum M und Sperrflüssigkeits-Dichtstufe 7 gewährleistet ist.Sealing elements, preferably spring-loaded (not shown) stuffing box packings or lip seal arrangements 31, are provided axially on both sides of the ring 19 in corresponding recesses on the housing side. The axial extent of the Widenings 23 ensure that axial displacements of the ring 19 are absorbed without impeding the flow of sealing liquid S, due to the setting of the spring-loaded gland packing. By choosing the barrier liquid S with the appropriate heat capacity, its flow through the stage 7 and the thermal conductivity between the axially external region of stage 3 and the flow paths of the barrier liquid S, the cooling in said region of stage 3, ie in FIG. 2, becomes axial outside area of the labyrinth seal, thus ensuring that when shaft 1 is at a standstill, for example in the case of a melt-pumping gear pump, taking into account the pressure drop in the bearing gap and possibly in the relief space, M, and the increase in viscosity of the conveying medium in the axially outer labyrinth seal area, the necessary tightness between said space M and sealing liquid sealing stage 7 is guaranteed.

Bevorzugterweise, und wie dargestellt, werden Labyrinthdichtung und Sperrflüssigkeitsstufe 7 in einer auswechselbaren Büchse 33 angeordnet, die auf einfache Art und Weise mit dem Gehäuse 15, durch welches durchgeführt wird, verbunden werden kann, wie verschraubt werden kann.Preferably, and as shown, the labyrinth seal and barrier liquid stage 7 are arranged in an interchangeable sleeve 33, which can be connected in a simple manner to the housing 15, through which is carried out, as can be screwed.

Die vorgeschlagene Wellendurchführung ist ausserordentlich servicefreundlich, und es entfallen alle periodischen Entleerungen irgendwelcher vorgesehener Leckzonen und Sammelräume. Es wird durch die Kühlung auch sichergestellt, dass die Betriebstemperaturen im Bereiche der Dichtungselemente 31, seien dies Stopfbuchspackungen oder Lippendichtungen, die hierfür vorgeschriebenen Temperaturen nicht überschreiten.The proposed shaft bushing is extremely easy to service, and all periodic emptying of any leak zones and collecting spaces provided is eliminated. The cooling also ensures that the operating temperatures in the area of the sealing elements 31, be they stuffing box packings or lip seals, do not exceed the temperatures prescribed for this.

Im weiteren muss die Kühlwirkung so sichergestellt sein, dass kurzzeitig, auch bei stillstehender Welle, gegen den Betriebsdruck im Raum M gedichtet wird, der sich, nach Stillsetzen der Welle 1, zeitlich verzögert, abbaut. Wie erwähnt, kann aber die Kühlwirkung durch die Temperatur, den Volumenstrom, die Wärmekapazität und die thermische Kopplung des Sperrmediums den Erfordernissen des jeweiligen Produktes angepasst werden.Furthermore, the cooling effect must be ensured in such a way that, even when the shaft is at a standstill, against the operating pressure is sealed in space M, which decelerates with a time delay after shaft 1 has stopped. As mentioned, the cooling effect can be adapted to the requirements of the respective product through the temperature, the volume flow, the heat capacity and the thermal coupling of the barrier medium.

Durch Anheben des Druckes im Sperrmediums-Kreislauf kann auch bei höherem Umgebungsdruck als Atmosphärendruck der Zutritt von Gas in den Raum M verhindert werden.By increasing the pressure in the barrier medium circuit, the entry of gas into the room M can be prevented even if the ambient pressure is higher than atmospheric pressure.

Eine Umwälzung der Dicht- und, erfindungsgemäss, Kühlflüssigkeit kann vorzugsweise durch Ausnützung der Thermosiphonwirkung oder durch Einsatz eines eigens dafür vorgesehenen Umwälzorganes vorgenommen werden. Als Umwälzorgan kann eine externe Pumpe vorgesehen sein oder die Welle in der Dichtkammer 21 so gestaltet sein, dass sie selbst als Umwälzorgan wirkt.Circulation of the sealing and, according to the invention, cooling liquid can preferably be carried out by utilizing the thermosiphon effect or by using a specially designed circulating element. An external pump can be provided as the circulating element, or the shaft in the sealing chamber 21 can be designed such that it itself acts as a circulating element.

Claims (8)

Verfahren zum Dichten einer Wellendurchführung in einen mediumsgefüllten Raum, worin sich der Druck in Funktion der Wellendrehzahl (n) verändert und wobei das Medium eine temperaturabhängige Viskositat (η) aufweist, dadurch gekennzeichnet, dass vom Raum (M) aus fortschreitend erst eine drehzahlabhängig wirkende Dichtung (3) vorgenommen wird, dann eine Sperrflüssigkeitsdichtung (7), und dass man mit der Sperrflüssigkeit (S) als Wärmetransportmedium den angrenzenden Bereich der drehzahlabhängigen Dichtung (3) derart kühlt, dass dort, weitgehendst drehzahlunabhängig, Dichtung erreicht wird, aufgrund der aus der Kühlung resultierenden Viskositätsänderung des Mediums.A method for sealing a shaft bushing in a medium-filled space, in which the pressure changes as a function of the shaft speed (n) and the medium has a temperature-dependent viscosity (η), characterized in that progressively only a speed-dependent sealing acts from the space (M) (3) is carried out, then a sealing liquid seal (7), and that one uses the sealing liquid (S) as the heat transfer medium to cool the adjacent area of the speed-dependent seal (3) in such a way that, largely largely independent of the speed, the seal is achieved due to the out of the Cooling resulting change in viscosity of the medium. Dichte Wellendurchführung in einen Raum für ein Medium, worin sich der Druck wellendrehzahlabhängig verändert, wobei die Viskosität (η) des Mediums mit zunehmender Temperatur abnimmt, dadurch gekennzeichnet, dass, ausgehend vom Raum (M), erst eine Labyrinthdichtung (17) mit Gewindeförderrichtung (F) gegen den Raum (M) hin vorgesehen ist und anschliessend eine Sperrflüssigkeitsdichtung (7), deren Sperrflüssigkeit (S) gleichzeitig als Kühlmedium für den angrenzenden Bereich der Labyrinthdichtung wirkt.Dense shaft passage in a space for a medium, in which the pressure changes depending on the shaft speed, the viscosity (η) of the medium decreasing with increasing temperature, characterized in that, starting from the space (M), only a labyrinth seal (17) with thread conveying direction ( F) is provided towards the room (M) and then a sealing liquid seal (7), the sealing liquid (S) of which also acts as a cooling medium for the adjacent area of the labyrinth seal. Wellendurchführung nach Anspruch 2, dadurch gekennzeichnet, dass die Sperrflüssigkeitsdichtung mindestens einen auf der Welle (1) angeordneten Ring (19) umfasst mit radialen, radial aussen axial aufgeweiteten Bohrungen, die mit mindestens einer Zuführleitung und mindestens einer Abführleitung (27, 29) für die Sperrflüssigkeit (S) gehäuseseitig kommunizieren, wobei die Axialausdehnung der Aufweitungen (23) eine axiale Verschiebung des Ringes (19) bezüglich der erwähnten Leitungen (27, 29) ermöglicht.Shaft bushing according to claim 2, characterized in that the sealing liquid seal comprises at least one ring (19) arranged on the shaft (1) with radial, radially axially widened bores which have at least one feed line and at least one discharge line (27, 29) for the Communicate barrier liquid (S) on the housing side, the axial expansion of the widenings (23) allowing the ring (19) to be axially displaced with respect to the lines (27, 29) mentioned. Wellendurchfuhrung nach Anspruch 3, dadurch gekennzeichnet, dass axial beidseits des Ringes an der Welle anliegende Dichtorgane (31), vorzugsweise Stopfbuchspackungen oder Lippendichtungen, vorgesehen sind.Shaft bushing according to claim 3, characterized in that sealing members (31), preferably gland packing or lip seals, are provided axially on both sides of the ring on the shaft. Wellendurchführung nach einem der Ansprüche 2 bis 4, dadurch gekennzeichnet, dass Labyrinthdichtung (17) und Sperrflüssigkeitsdichtung (7) an einem lösbar an einem Gehäuse befestigbaren Einsatz (33) angeordnet sind.Shaft bushing according to one of claims 2 to 4, characterized in that the labyrinth seal (17) and sealing liquid seal (7) are arranged on an insert (33) which can be detachably attached to a housing. Wellendurchführung nach einem der Ansprüche 2 bis 5, dadurch gekennzeichnet, dass ein Thermosiphon-Umwälzkreis für die Sperrflüssigkeit (S) vorgesehen ist oder ein Umwälzaggregat hierfür, vorzugsweise gebildet durch eine externe Pumpe und/oder Umwälzorgane an der Welle (1) im Bereich der Sperrflüssigkeitsdichtung (7).Shaft feedthrough according to one of claims 2 to 5, characterized in that a thermosiphon circulating circuit is provided for the barrier liquid (S) or a circulating unit therefor, preferably formed by an external pump and / or circulating elements on the shaft (1) in the region of the barrier liquid seal (7). Zahnradpumpe mit mindestens einer Wellendurchführung nach einem der Ansprüche 2 bis 6.Gear pump with at least one shaft bushing according to one of claims 2 to 6. Verwendung der Zahnradpumpe nach Anspruch 7 zur Förderung von Polymerschmelzen.Use of the gear pump according to claim 7 for the promotion of polymer melts.
EP93111510A 1993-07-17 1993-07-17 Method and arrangement for sealing a shaft passage in gear pumps Expired - Lifetime EP0643223B1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
AT93111510T ATE163074T1 (en) 1993-07-17 1993-07-17 METHOD AND ARRANGEMENT FOR SEALING A SHAFT PASSAGE IN GEAR PUMPS
EP93111510A EP0643223B1 (en) 1993-07-17 1993-07-17 Method and arrangement for sealing a shaft passage in gear pumps
DE59308121T DE59308121D1 (en) 1993-07-17 1993-07-17 Method and arrangement for sealing a shaft bushing in gear pumps

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP93111510A EP0643223B1 (en) 1993-07-17 1993-07-17 Method and arrangement for sealing a shaft passage in gear pumps

Publications (2)

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EP0643223A1 true EP0643223A1 (en) 1995-03-15
EP0643223B1 EP0643223B1 (en) 1998-02-04

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EP93111510A Expired - Lifetime EP0643223B1 (en) 1993-07-17 1993-07-17 Method and arrangement for sealing a shaft passage in gear pumps

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EP (1) EP0643223B1 (en)
AT (1) ATE163074T1 (en)
DE (1) DE59308121D1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010132154A3 (en) * 2009-05-12 2011-05-12 Illinois Tool Works Inc. Seal system for gear pumps
CN108527813A (en) * 2018-04-20 2018-09-14 浙江厚普科技有限公司 Without silk screen filter equipment and self sealss cooling transmission device
CN109751238A (en) * 2019-02-22 2019-05-14 郑州沃华机械有限公司 A kind of smelt gear pump and its sealing structure

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102377227B1 (en) 2017-03-09 2022-03-22 존슨 컨트롤스 테크놀러지 컴퍼니 Back-to-back bearing sealing system

Citations (4)

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Publication number Priority date Publication date Assignee Title
US3976405A (en) * 1974-10-29 1976-08-24 Cominco Ltd. Pump
DE3135037A1 (en) * 1980-09-12 1982-09-23 Barmag Barmer Maschinenfabrik Ag, 5630 Remscheid Discharge pump
US4575100A (en) * 1984-11-05 1986-03-11 The Dow Chemical Company Seal assembly which is hydraulically actuated
WO1989008782A1 (en) * 1988-03-17 1989-09-21 Johnson Pump Ab Pump arrangement in which the pump housing constitutes the pump foundation

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3976405A (en) * 1974-10-29 1976-08-24 Cominco Ltd. Pump
DE3135037A1 (en) * 1980-09-12 1982-09-23 Barmag Barmer Maschinenfabrik Ag, 5630 Remscheid Discharge pump
US4575100A (en) * 1984-11-05 1986-03-11 The Dow Chemical Company Seal assembly which is hydraulically actuated
WO1989008782A1 (en) * 1988-03-17 1989-09-21 Johnson Pump Ab Pump arrangement in which the pump housing constitutes the pump foundation

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010132154A3 (en) * 2009-05-12 2011-05-12 Illinois Tool Works Inc. Seal system for gear pumps
CN108527813A (en) * 2018-04-20 2018-09-14 浙江厚普科技有限公司 Without silk screen filter equipment and self sealss cooling transmission device
CN108527813B (en) * 2018-04-20 2024-04-12 浙江厚普科技有限公司 Silk-screen-free filtering equipment and self-sealing cooling transmission device
CN109751238A (en) * 2019-02-22 2019-05-14 郑州沃华机械有限公司 A kind of smelt gear pump and its sealing structure
CN109751238B (en) * 2019-02-22 2024-03-08 郑州沃华机械有限公司 Melt gear pump and sealing structure thereof

Also Published As

Publication number Publication date
DE59308121D1 (en) 1998-03-12
EP0643223B1 (en) 1998-02-04
ATE163074T1 (en) 1998-02-15

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