EP0446206B1 - Process and device for control of a twin-cylinder thick matter pump - Google Patents

Process and device for control of a twin-cylinder thick matter pump Download PDF

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Publication number
EP0446206B1
EP0446206B1 EP89908162A EP89908162A EP0446206B1 EP 0446206 B1 EP0446206 B1 EP 0446206B1 EP 89908162 A EP89908162 A EP 89908162A EP 89908162 A EP89908162 A EP 89908162A EP 0446206 B1 EP0446206 B1 EP 0446206B1
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EP
European Patent Office
Prior art keywords
reversing
delivery
pump
switch
hydraulic
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.)
Expired - Lifetime
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EP89908162A
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German (de)
French (fr)
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EP0446206A1 (en
Inventor
Hartmut Benckert
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Putzmeister Concrete Pumps GmbH
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Putzmeister Werk Maschinenfabrik GmbH
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B7/00—Piston machines or pumps characterised by having positively-driven valving
    • F04B7/02—Piston machines or pumps characterised by having positively-driven valving the valving being fluid-actuated
    • F04B7/0233—Piston machines or pumps characterised by having positively-driven valving the valving being fluid-actuated a common distribution member forming a single discharge distributor for a plurality of pumping chambers
    • F04B7/0258—Piston machines or pumps characterised by having positively-driven valving the valving being fluid-actuated a common distribution member forming a single discharge distributor for a plurality of pumping chambers and having an orbital movement, e.g. elbow-pipe type members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B9/00—Piston machines or pumps characterised by the driving or driven means to or from their working members
    • F04B9/08—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid
    • F04B9/10—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid
    • F04B9/109—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid having plural pumping chambers
    • F04B9/117—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid having plural pumping chambers the pumping members not being mechanically connected to each other
    • F04B9/1176—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid having plural pumping chambers the pumping members not being mechanically connected to each other the movement of each piston in one direction being obtained by a single-acting piston liquid motor
    • F04B9/1178—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid having plural pumping chambers the pumping members not being mechanically connected to each other the movement of each piston in one direction being obtained by a single-acting piston liquid motor the movement in the other direction being obtained by a hydraulic connection between the liquid motor cylinders

Definitions

  • the invention relates to a method and a device for controlling a thick matter pump with two delivery cylinders opening into the material feed container via front openings, which can be actuated in push-pull mode by means of at least one hydraulic reversing pump and controlled by this hydraulic drive cylinder, with a feed cylinder arranged inside the material feed container and alternately on the inlet side the delivery cylinder can be connected and the other opening can be opened and the outlet side can be connected to a delivery line, hydraulically actuated pipe switch, whereby a reversal process of the pipe switch is triggered at the end of the pressure stroke in the delivery cylinders and the thick matter feed is interrupted during the changeover process.
  • a method for controlling a two-cylinder slurry pump of this type is known (DE-OS 32 53 576), in which both the drive cylinder of the delivery cylinder and the hydraulic actuators of the pipe switch are acted upon directly by the pressure oil delivered by the hydraulic reversing pump.
  • 2/2-way seat valves are installed in the lines of the main delivery circuit leading to the drive cylinders, which in turn can be controlled via a delay valve.
  • the reversing pump is switched by an electrical end position signal at the end of each pressure stroke triggered. In order to avoid that the thick material previously sucked into the feed cylinder is not conveyed back into the material feed container.
  • the delay valve is reversed so that the 2/2 directional seated valves are brought into their closed position, so that the pressure medium cannot flow from the reversing pump into the lines leading to the drive cylinders.
  • a sufficient pressure builds up in the respective high-pressure line leading to the actuating members in order to connect the hydraulic actuating members of the pipe switch via a reversing valve.
  • the object of the invention is to develop a method and a device for controlling a thick matter pump of the type specified at the beginning, with which hydraulic sequence control of the drive cylinders and the pipe switch is possible without fittings in the main oil circuit.
  • a hydraulic or electrical end position signal to trigger the reversing process is tapped off on the pipe switch or on its hydraulic actuating members after each switchover process.
  • the pressure oil supply to the actuators of the pipe switch is interrupted or reversed with compensation for the oil flow reversal in the main circuit.
  • the hydraulic actuators of the pipe switch are expediently held under the action of the pressure generated by the reversing pump until a reversal process is triggered when the pressure stroke is ended while maintaining the conveying direction of the reversing pump.
  • the delivery volume and / or the delivery pressure of the reversing pump is changed while maintaining the delivery direction when the reversing process of the pipe switch is triggered.
  • the reversing pump can be briefly controlled to the maximum delivery volume and then readjusted in accordance with a predetermined delivery volume or delivery pressure
  • the free-flow circuit according to the invention makes it possible for at least one additional reversing pump to be connected in parallel in the main circuit in the event of higher demands on the delivery rate, without additional measures, in particular without exchanging other fittings.
  • a device for carrying out the method according to the invention advantageously has an adjusting and regulating mechanism for setting the delivery direction and, if appropriate, the delivery rate of the reversing pump, which can be acted upon with hydraulic or electrical end position signals which can be tapped at the pipe switch or at its hydraulic actuating members.
  • the hydraulic actuators of the pipe switch can be acted upon with pressure oil branched from the valve-free main circuit leading from the reversing pump to the drive cylinders.
  • an inversion element that responds to a return signal and reverses the delivery direction of the reversing pump is arranged in the circuit arrangement that transmits the hydraulic and electrical end position signals.
  • a directional control valve which reverses the direction of the pressure oil supply is expediently arranged in the hydraulic line branching off from the main circuit and leading to the hydraulic actuators of the pipe switch, which directional control valve can be actuated via a pilot signal which responds to the conveying direction of the reversing pump.
  • a further directional control valve which can be actuated by end position signals from the feed cylinder or from its drive cylinders, can be arranged, which can be switched over when a pressure stroke is ended and which triggers the reversing process of the pipe switch.
  • the single figure shows the circuit of a control arrangement for a free-flow sequence control of drive cylinders and tubular switch cylinders in a single circuit arrangement.
  • the thick matter pump essentially consists of two delivery cylinders 1, 1 ', the end openings 2, 2' of which open into a material feed container (not shown) and can be connected alternately to a delivery line 4 via a pipe switch 3 during the pressure stroke.
  • the delivery cylinders 1, 1 ' are driven in a push-pull manner via hydraulic drive cylinders 5, 5' and the reversing hydraulic pump 6, which is designed as a swash plate axial piston pump in the exemplary embodiment shown.
  • the delivery pistons 7,7 ' are connected to the pistons 8,8' of the drive cylinders 5,5 'via a common piston rod 9,9'.
  • the drive cylinders 5, 5 ' are pressurized with pressure oil on the bottom side via the pressure lines 11, 11' of the main circuit with the aid of the reversing pump 6 and are hydraulically connected to one another at their rod-side end via a cross line 12.
  • a pressure compensation line 14 which contains a check valve 13 and bridges the relevant drive piston 8 'in its end positions, is arranged at the two ends of the drive cylinder 5'.
  • the direction of movement of the drive piston 8,8 'and thus the delivery piston 7,7' is reversed in that the swash plate 15 of the reversing pump 6 is triggered by a reversal signal is pivoted through the zero position and thus the direction of delivery of the pressure oil in the lines 11, 11 'of the main circuit changes in the free flow.
  • the delivery rate of the reversing pump 6 is determined by the swivel angle of the swash plate 15 at a predetermined drive speed.
  • the swash plate angle and thus the delivery rate is adjustable in proportion to a control pressure p s , which actuates the actuating cylinder 18 via the lines 16, 17 and 17 'and the reversing valve 20 located in the relevant line path.
  • the control pressure p s can be varied in accordance with the switching states of the thick matter pump with hydraulic or electrical means, not shown.
  • pressure regulators 70 and 71 are provided, the control inputs of which can be connected via a shuttle valve 72 or a directional valve 73 to the line 11, 11 'of the main circuit which carries high pressure or low pressure, respectively.
  • the switchover of the pipe switch 3 takes place via the hydraulic cylinders 21, 21 ', which are preferably designed as plunger cylinders and which act directly on the pressure oil delivered by the reversing pump 6 via the lines 22, 22' branched off from the main circuit, the reversing valve 30 and the pressure lines 23, 23 ' will.
  • the pilot control of the reversing valve 30 takes place hydraulically via the lines 24, 24 ′, which via the directional valves 31 and 40 with the control pressure of one together with the reversing pump 6 driven auxiliary pump 25 can be acted upon.
  • the directional control valve 31 can be actuated via the electrically or optionally also hydraulically tapped end position signals x or xx of the drive cylinder 5, while the directional control valve 40 according to the pressure prevailing in the control lines 17, 17 'leading to the actuating cylinder 18 via the lines 28, 28' is reversible.
  • the main control valve 20, which determines the delivery direction of the reversing pump 6, is actuated via end position signals of the pipe switch cylinders 21, 21 ', which can be tapped via the hydraulic lines 26, 26' and / or via electrical signal transmitters y.
  • the auxiliary pump 25 also charges the closed main circuit via the check valves 75, 75 'and is protected by the pressure relief valve 74.
  • the circuit arrangement shown leads to a sequential control of the drive cylinders 5.5 'and the tubular switch cylinders 21.21', which functions as follows:
  • a reversal of the directional control valve 31 is triggered via the electrically tapped end position signal x.
  • the reversing valve 30 is reversed while triggering a reversing process on the pipe switch cylinders 21, 21 ', the direction of delivery of the reversing pump 6 initially being retained and the drive piston 8, 8' over the Pressure oil in line 11 are kept in their respective end positions.
  • the valve 20 is reversed via the corresponding end position signal.
  • the pilot control on the actuating cylinder 18 changes, so that the swash plate 15 of the reversing pump 6 swivels with reversal of the conveying direction.
  • the reversal signal is tapped in parallel between the valve 20 and the actuating cylinder 18 and switched to the pilot control of the valve 40 via the lines 28, 28 '.
  • the valve 40 thus changes its position and thus ensures that the tube switch cylinders 21, 21 'maintain the previously assumed end position despite the reversal of the direction of delivery of the reversing pump 6.
  • pilot valve 40 Since the pilot valve 40 responds to the reversal signal faster than the reversing pump 6, adjustable throttles 29, 29 'are arranged in the pilot lines 28, 28', which are adapted to the time behavior in order to avoid an undesired downshift of the pipe switch cylinders 21, 21 'in the course of the reversal of the conveying direction the reversing pump 6 cause the pilot valve 40 and thus the directional control valve 30 to slowly switch through.
  • the return valve 32 upstream of the reversing valve 20 in the control lines 26, 26 ', the drive cylinders 5, 5' can be acted upon in the opposite manner if necessary, so that material is conveyed back from the delivery line into the storage container.
  • the single-circuit arrangement described is above all: suitable for smaller or slow-running systems at who need the smallest possible number of hydraulic assemblies.
  • a two-circuit sequential circuit is suitable, in which the diverter switch valve 30 is not connected to the main circuit via lines 22, 22 ', but to a separate hydraulic circuit. In the latter case, the directional control valve 40 can be omitted.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

The invention concerns a sequence-control unit for a twin-cylinder thick matter pump with two delivery cylinders (1, 1') discharging through front-located openings (2, 2') into a hopper, and a hydraulically operated pipe switch (3) which is located inside the hopper and can be connected on the input side to each of the openings (2, 2') of the delivery cylinders (1, 1') in turn, leaving the other opening free, and which can be connected on the output side to a delivery line (4). The delivery cylinders (1, 1') are connected to hydraulic drive cylinders (5, 5') which are operated in a push-pull mode by at least one hydraulic reversing-pump (6). At the end of each delivery-cylinder compression stroke, a pipe-switch changeover operation is initiated and during the changeover operation the delivery of thick matter is interrupted. During the pipe-switch changeover operation, the reversing-pump delivery direction is initially kept unchanged, maintaining a free supply of hydraulic fluid to the drive cylinders (5, 5'), and it is not until completion of the pipe-switch changeover operation that the delivery direction is reversed. To initiate the reversal process, a hydraulic or electrical end-limit signal (y, y, 26, 26') is detected at the pipe-switch (3) or at its hydraulic actuating elements (21, 21') after each switchover operation.

Description

Die Erfindung betrifft ein Verfahren und eine Vorrichtung zur Steuerung einer Dickstoffpumpe mit zwei über stirnseitige Öffnungen in einen Materialaufgabebehälter mündenden, mittels mindestens einer hydraulischen Reversierpumpe und über diese angesteuerter hydraulischer Antriebszylinder im Gegentakt betätigbaren Förderzylindern, mit einer innerhalb des Materialaufgabebehälters angeordneten, eintrittsseitig abwechselnd an die Öffnungen der Förderzylinder anschließbaren und die jeweils andere Öffnung freigebenden und austrittsseitig mit einer Förderleitung verbindbaren, hydraulisch betätigbaren Rohrweiche, wobei jeweils bei Beendigung des Druckhubs in den Förderzylindern ein Umsteuervorgang der Rohrweiche ausgelöst und während des Umsteuervorgangs die Dickstofförderung unterbrochen wird.The invention relates to a method and a device for controlling a thick matter pump with two delivery cylinders opening into the material feed container via front openings, which can be actuated in push-pull mode by means of at least one hydraulic reversing pump and controlled by this hydraulic drive cylinder, with a feed cylinder arranged inside the material feed container and alternately on the inlet side the delivery cylinder can be connected and the other opening can be opened and the outlet side can be connected to a delivery line, hydraulically actuated pipe switch, whereby a reversal process of the pipe switch is triggered at the end of the pressure stroke in the delivery cylinders and the thick matter feed is interrupted during the changeover process.

Es ist ein Verfahren zur Steuerung einer Zweizylinder-Dickstoffpumpe dieser Art bekannt (DE-OS 32 53 576), bei welchem sowohl die Antriebszylinder der Förderzylinder als auch die hydraulischen Betätigungsorgane der Rohrweiche unmittelbar mit dem von der hydraulischen Reversierpumpe geförderten Drucköl beaufschlagt werden. Allerdings sind dort in die zu den Antriebszylindern führenden Leitungen des Hauptförderkreises 2/2-Wegesitzventile eingebaut, die ihrerseits über ein Verzögerungsventil ansteuerbar sind. Die Umschaltung der Reversierpumpe wird jeweils unmittelbar bei Beendigung eines Druckhubs durch ein elektrisches Endlagensignal ausgelöst. Um zu vermeiden, daß das in den einen Förderzylinder zuvor angesaugte Dickstoffmaterial nicht wieder zurück in den Materialaufgabebehälter gefördert. wird, wird im Moment der Umschaltung der Reversierpumpe das Verzögerungsventil so umgesteuert, daß die 2/2 Wegesitzventile in ihre Schließstellung gebracht werden, so daß das Druckmittel nicht von der Reversierpumpe in die zu den Antriebszylindern führenden Leitungen fließen kann. Gleichzeitig baut sich in der jeweiligen zu den Betätigungsorganen führenden Hochdruckleitung ein genügender Druck auf, um über ein Umsteuerventil die hydraulischen Betätigungsorgane der Rohrweiche durchzuschalten. Mittels einer Drosselkette wird die Durchschaltung des Umsteuerventils so lange verzögert, bis die Rohrweiche umgeschaltet ist. Danach werden die 2/2-Wegesitzventile wieder für beide Durchflußrichtungen geöffnet. Vor allem beim Transport von Dickstoffen mit Grobbestandteilen oder bei aushärtenden Dickstoffen, wie Beton, kann es allerdings vorkommen, daß die Rohrweiche im Zuge der Umschaltung verklemmt und daher nicht ganz durchschaltet. Da nach Ablauf der an der Drosselkette eingestellten Verzögerungszeit die im Hauptkreislauf angeordneten Sitzventile automatisch öffnen, führt dies dazu, daß das zuvor von einem Förderzylinder angesaugte Material ungewollt in den Materialaufgabebehälter zurückgefördert wird. Wenn sich dieses Spiel bei bleibenden Verklemmungen wiederholt, kann dies zu einem raschen Verschleiß oder gar zu Zerstörungen im Rohrweichenbereich führen. Weiter hat es sich bei der bekannten Schaltungsanordnung als nachteilig erwiesen, daß in dem von der Reversierpumpe zu den Antriebszylindern führenden Hauptkreislauf Sitzventile angeordnet bind, deren Baugröße an den Hauptölstrom angepaßt werden muß. Eine Erhöhung der Fördermenge unter Zuschaltung zusätzlicher, prallelgeschalteter Reversierpumpen ist daher ohne gleichzeitigen Austausch der Wegesitzventile im Hauptkreislauf nicht möglich, wenn diese nicht von vornherein überdimensioniert sind.A method for controlling a two-cylinder slurry pump of this type is known (DE-OS 32 53 576), in which both the drive cylinder of the delivery cylinder and the hydraulic actuators of the pipe switch are acted upon directly by the pressure oil delivered by the hydraulic reversing pump. However, 2/2-way seat valves are installed in the lines of the main delivery circuit leading to the drive cylinders, which in turn can be controlled via a delay valve. The reversing pump is switched by an electrical end position signal at the end of each pressure stroke triggered. In order to avoid that the thick material previously sucked into the feed cylinder is not conveyed back into the material feed container. is, at the moment the reversing pump is switched over, the delay valve is reversed so that the 2/2 directional seated valves are brought into their closed position, so that the pressure medium cannot flow from the reversing pump into the lines leading to the drive cylinders. At the same time, a sufficient pressure builds up in the respective high-pressure line leading to the actuating members in order to connect the hydraulic actuating members of the pipe switch via a reversing valve. By means of a throttle chain, the switching of the changeover valve is delayed until the pipe switch is switched. Then the 2/2-way seat valves are opened again for both flow directions. Especially when transporting thick materials with coarse constituents or hardening thick materials such as concrete, however, it can happen that the pipe switch is jammed in the course of the switchover and therefore not fully switched through. Since the seat valves arranged in the main circuit automatically open after the delay time set on the throttle chain has elapsed, this leads to the material previously sucked in by a feed cylinder being unwantedly conveyed back into the material feed container. If this game repeats itself with permanent jamming, this can lead to rapid wear or even destruction in the pipe switch area. Furthermore, it has proven disadvantageous in the known circuit arrangement proved that seat valves are arranged in the main circuit leading from the reversing pump to the drive cylinders, the size of which must be adapted to the main oil flow. It is therefore not possible to increase the delivery rate by connecting additional, parallel-connected reversing pumps without simultaneously replacing the directional seated valves in the main circuit if they are not oversized from the outset.

Ausgehend hiervon liegt der Erfindung die Aufgabe zugrunde, ein Verfahren und eine Vorrichtung zur Steuerung einer Dickstoffpumpe der eingangs angegebenen Art zu entwickeln, womit ohne Armaturen im Hauptölkreis eine hydraulische Folgesteuerung der Antriebszylinder und der Rohrweiche möglich ist.Proceeding from this, the object of the invention is to develop a method and a device for controlling a thick matter pump of the type specified at the beginning, with which hydraulic sequence control of the drive cylinders and the pipe switch is possible without fittings in the main oil circuit.

Zur Lösung dieser Aufgabe werden gemäß der Erfindung die in den Ansprüchen 1 bzw. 8 angegebenen Merkmalskombinationen vorgeschlagen. Weitere vorteilhafte Ausgestaltungen und Weiterbildungen der Erfindung ergeben sich aus den abhängigen Ansprüchen.To achieve this object, the feature combinations specified in claims 1 and 8 are proposed according to the invention. Further advantageous refinements and developments of the invention result from the dependent claims.

Mit der erfindungsgemäßen Verfahrensweise, bei der während des Umsteuervorgangs der Rohrweiche die Förderrichtung der Reversierpumpe unter Aufrechterhaltung einer freien Druckölzufuhr zu den Antriebszylindern beibehalten und erst bei Beendigung des Umsteuervorgangs der Rohrweiche die Förderrichtung der Reversierpumpe umgekehrt wird, wird der Förderbetrieb unterbrochen, wenn die Rohrweiche, etwa infolge von Verklemmungen, nicht vollständig durchschalten sollte. Mit den erfindungsgemäßen Maßnahmen ist es möglich, daß die Antriebszylinder und die Rohrweichen-Umsteuerorgane in einem Einkreissystem arbeiten und die Antriebszylinder trotzdem im Freifluß mit Drucköl beaufschlagbar sind. Das bedeutet, daß zur Umsteuerung der Rohrweiche Drucköl unmittelbar aus einem von der Reversierpumpe zu den Antriebszylindern führenden, armaturenfreien Hauptkreislauf abgezweigt wird. Dabei werden die Kolben der Antriebszylinder während des Umsteuervorgangs der Rohrweiche unter der Einwirkung des von der Reversierpumpe im Hauptkreislauf erzeugten Druckes auf Endanschlag gehalten, bis der Umsteuervorgang der Rohrweiche beendet ist.With the procedure according to the invention, in which the conveying direction of the reversing pump is maintained while maintaining a free pressure oil supply to the drive cylinders during the reversing process of the pipe switch and the conveying direction of the reversing pump is only reversed when the reversing process of the pipe switch is ended, the conveying operation is interrupted when the pipe switch, for example due to jams, should not switch through completely. With the measures according to the invention, it is possible that the drive cylinders and the switching points reversing elements work in a single-circuit system and the drive cylinders can nevertheless be acted upon in the free flow with pressure oil. This means that pressure oil is diverted directly from a valve-free main circuit leading from the reversing pump to the drive cylinders in order to reverse the pipe switch. The pistons of the drive cylinders are held at the end stop during the reversing process of the pipe switch under the influence of the pressure generated by the reversing pump in the main circuit until the reversing process of the pipe switch is completed.

Vorteilhafterweise wird an der Rohrweiche oder an deren hydraulischen Betätigungsorganen nach jedem Umschaltvorgang ein vorzugsweise hydraulisches oder elektrisches Endlagensignal zur Auslösung des Reversiervorgangs abgegriffen. Zugleich wird die Druckölzufuhr zu den Betätigungsorganen der Rohrweiche unterbrochen oder unter Kompensation der Ölstromumkehrung im Hauptkreislauf umgekehrt. Im Anschluß daran, während der Dickstofförderung, werden zweckmäßig die hydraulischen Betätigungsorgane der Rohrweiche unter der Einwirkung des von der Reversierpumpe erzeugten Druckes auf Endanschlag gehalten, bis bei Beendigung des Druckhubs unter Beibehaltung der Förderrichtung der Reversierpumpe ein Umsteuervorgang ausgelöst wird.Advantageously, a hydraulic or electrical end position signal to trigger the reversing process is tapped off on the pipe switch or on its hydraulic actuating members after each switchover process. At the same time, the pressure oil supply to the actuators of the pipe switch is interrupted or reversed with compensation for the oil flow reversal in the main circuit. Subsequently, during the thick matter conveyance, the hydraulic actuators of the pipe switch are expediently held under the action of the pressure generated by the reversing pump until a reversal process is triggered when the pressure stroke is ended while maintaining the conveying direction of the reversing pump.

Gemäß einer weiteren vorteilhaften Ausgestaltung des erfindungsgemäßen Verfahrens wird bei Auslösung des Umsteuervorgangs der Rohrweiche das Fördervolumen und/oder der Förderdruck der Reversierpumpe unter Beibehaltung der Förderrichtung geändert. Insbesondere kann die Reversierpumpe beim Auslösen des Reversiervorgangs kurzzeitig auf maximales Fördervolumen durchgesteuert und anschließend nach Maßgabe eines vorgegebenen Fördervolumens oder Förderdrucks nachgeregelt werdenAccording to a further advantageous embodiment of the method according to the invention, the delivery volume and / or the delivery pressure of the reversing pump is changed while maintaining the delivery direction when the reversing process of the pipe switch is triggered. In particular, when the reversing process is triggered, the reversing pump can be briefly controlled to the maximum delivery volume and then readjusted in accordance with a predetermined delivery volume or delivery pressure

Die erfindungsgemäße Freiflußschaltung ermöglicht es, daß bei höheren Anforderungen an die Fördermenge ohne zusätzliche Maßnahmen, insbesondere ohne Austausch von sonstigen Armaturen, in den Hauptkreislauf mindestens eine weitere Reversierpumpe in Parallelschaltung zugeschaltet werden kann.The free-flow circuit according to the invention makes it possible for at least one additional reversing pump to be connected in parallel in the main circuit in the event of higher demands on the delivery rate, without additional measures, in particular without exchanging other fittings.

Eine Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens weist vorteilhafterweise einen Stell- und Regelmechanismus zur Einstellung der Förderrichtung und gegebenenfalls der Fördermenge der Reversierpumpe auf, der mit an der Rohrweiche oder an deren hydraulischen Betätigungsorganen abgreifbaren hydraulischen oder elektrischen Endlagensignalen beaufschlagbar ist. Die hydraulischen Betätigungsorgane der Rohrweiche sind dabei mit aus dem von der Reversierpumpe zu den Antriebszylindern führenden, armaturenfreien Hauptkreislauf abgezweigtem Drucköl beaufschlagbar. Um zusätzlich eine Rückförderung von Material aus der Förderleitung über die Rohrweiche zurück in den Förderzylinder und vom anderen Förderzylinder in den Materialaufgabebehälter zu ermöglichen, ist in der die hydraulischen und elektrischen Endlagensignale übertragenden Schaltungsanordnung ein auf ein Rückfördersignal ansprechendes, die Förderrichtung der Reversierpumpe umkehrendes Inversionsglied angeordnet.A device for carrying out the method according to the invention advantageously has an adjusting and regulating mechanism for setting the delivery direction and, if appropriate, the delivery rate of the reversing pump, which can be acted upon with hydraulic or electrical end position signals which can be tapped at the pipe switch or at its hydraulic actuating members. The hydraulic actuators of the pipe switch can be acted upon with pressure oil branched from the valve-free main circuit leading from the reversing pump to the drive cylinders. To additionally return material from the conveyor line To enable via the pipe switch back into the delivery cylinder and from the other delivery cylinder into the material feed container, an inversion element that responds to a return signal and reverses the delivery direction of the reversing pump is arranged in the circuit arrangement that transmits the hydraulic and electrical end position signals.

Weiter ist zweckmäßig in der vom Hauptkreislauf abgezweigten, zu den hydraulischen Betätigungsorganen der Rohrweiche führenden Hydraulikleitung ein die Richtung der Druckölzufuhr umsteuerndes Wegeventil angeordnet, das über ein auf die Förderrichtung der Reversierpumpe ansprechendes Vorsteuersignal betätigbar ist. In den zum Wegeventil führenden Vorsteuerleitungen kann ein weiteres, durch Endlagensignale des Förderzylinders oder von dessen Antriebszylindern betätigbares Wegeventil angeordnet werden, das bei Beendigung eines Druckhubes umschaltbar ist und den Umsteuervorgang der Rohrweiche auslöst.Furthermore, a directional control valve which reverses the direction of the pressure oil supply is expediently arranged in the hydraulic line branching off from the main circuit and leading to the hydraulic actuators of the pipe switch, which directional control valve can be actuated via a pilot signal which responds to the conveying direction of the reversing pump. In the pilot control lines leading to the directional control valve, a further directional control valve, which can be actuated by end position signals from the feed cylinder or from its drive cylinders, can be arranged, which can be switched over when a pressure stroke is ended and which triggers the reversing process of the pipe switch.

Im folgenden wird die Erfindung anhand eines in der Zeichnung in schematischer Weise dargestellten Ausführungsbeispiels näher erläutert.The invention is explained in more detail below with reference to an exemplary embodiment shown schematically in the drawing.

Die einzige Figur zeigt den Schaltkreis einer Steuerungsanordnung für eine Freifluß-Folgesteuerung von Antriebszylindern und Rohrweichenzylindern in Einkreisanordnung.The single figure shows the circuit of a control arrangement for a free-flow sequence control of drive cylinders and tubular switch cylinders in a single circuit arrangement.

Die Dickstoffpumpe besteht im wesentlichen aus zwei Förderzylindern 1,1', deren stirnseitige Öffnungen 2,2' in einen nicht dargestellten Materialaufgabebehälter münden und abwechselnd während des Druckhubs über eine Rohrweiche 3 mit einer Förderleitung 4 verbindbar sind. Die Förderzylinder 1,1' werden über hydraulische Antriebszylinder 5,5' und die im gezeigten Ausführungsbeispiel als Schrägscheiben-Axialkolbenpumpe ausgebildete Reversier-Hydropumpe 6 im Gegentakt angetrieben. Zu diesem Zweck sind die Förderkolben 7,7' mit den Kolben 8,8' der Antriebszylinder 5,5' über eine gemeinsame Kolbenstange 9,9' verbunden. Zwischen den Förderzylindern 1,1' und den Antriebszylindern 5,5' befindet sich ein Wasserkasten 10, durch den die Kolbenstangen 9,9' hindurchgreifen.The thick matter pump essentially consists of two delivery cylinders 1, 1 ', the end openings 2, 2' of which open into a material feed container (not shown) and can be connected alternately to a delivery line 4 via a pipe switch 3 during the pressure stroke. The delivery cylinders 1, 1 'are driven in a push-pull manner via hydraulic drive cylinders 5, 5' and the reversing hydraulic pump 6, which is designed as a swash plate axial piston pump in the exemplary embodiment shown. For this purpose, the delivery pistons 7,7 'are connected to the pistons 8,8' of the drive cylinders 5,5 'via a common piston rod 9,9'. Between the delivery cylinders 1, 1 'and the drive cylinders 5, 5' there is a water box 10 through which the piston rods 9, 9 'reach.

Die Antriebszylinder 5,5' werden im gezeigten Ausführungsbeispiel bodenseitig über die Druckleitungen 11,11' des Hauptkreislaufs mit Hilfe der Reversierpumpe 6 mit Drucköl beaufschlagt und sind an ihrem stangenseitigen Ende über eine Querleitung 12 hydraulisch miteinander verbunden. Zum Zwecke der Hubkorrektur ist an den beiden Enden des Antriebszylinders 5' je eine den betreffenden Antriebskolben 8' in dessen Endstellungen überbrückende, ein Rückschlagventil 13 enthaltende Druckausgleichsleitung 14 angeordnet.In the exemplary embodiment shown, the drive cylinders 5, 5 'are pressurized with pressure oil on the bottom side via the pressure lines 11, 11' of the main circuit with the aid of the reversing pump 6 and are hydraulically connected to one another at their rod-side end via a cross line 12. For the purpose of stroke correction, a pressure compensation line 14, which contains a check valve 13 and bridges the relevant drive piston 8 'in its end positions, is arranged at the two ends of the drive cylinder 5'.

Die Bewegungsrichtung der Antriebskolben 8,8' und damit der Förderkolben 7,7' wird dadurch umgekehrt, daß die Schrägscheibe 15 der Reversierpumpe 6 ausgelöst durch ein Umsteuersignal durch die Null-Lage hindurchgeschwenkt und damit die Förderrichtung des Dru'cköls in den Leitungen 11,11' des Hauptkreislaufs im Freifluß wechselt. Die Fördermenge der Reversierpumpe 6 wird bei vorgegebener Antriebsdrehzahl durch den Schwenkwinkel der Schrägscheibe 15 bestimmt. Der Schrägscheibenwinkel und damit die Fördermenge ist proportional zu einem Steuerdruck ps verstellbar, der über die Leitungen 16,17 und 17' und das im betreffenden Leitungsweg befindliche Umsteuerventil 20 den Stellzylinder 18 betätigt. Der Steuerdruck ps kann nach Maßgabe der Schaltzustände der Dickstoffpumpe mit nicht dargestellten hydraulischen oder elektrischen Mitteln variiert werden. Zur Einstellung des Hochdruck- und Niederdruckniveaus im Hauptkreislauf sind Druckregler 70 und 71 vorgesehen, deren Steuereingänge über ein Wechselventil 72 bzw. ein Wegeventil 73 mit der jeweils Hochdruck bzw. Niederdruck führenden Leitung 11,11' des Hauptkreislaufes verbindbar sind.The direction of movement of the drive piston 8,8 'and thus the delivery piston 7,7' is reversed in that the swash plate 15 of the reversing pump 6 is triggered by a reversal signal is pivoted through the zero position and thus the direction of delivery of the pressure oil in the lines 11, 11 'of the main circuit changes in the free flow. The delivery rate of the reversing pump 6 is determined by the swivel angle of the swash plate 15 at a predetermined drive speed. The swash plate angle and thus the delivery rate is adjustable in proportion to a control pressure p s , which actuates the actuating cylinder 18 via the lines 16, 17 and 17 'and the reversing valve 20 located in the relevant line path. The control pressure p s can be varied in accordance with the switching states of the thick matter pump with hydraulic or electrical means, not shown. To set the high and low pressure levels in the main circuit, pressure regulators 70 and 71 are provided, the control inputs of which can be connected via a shuttle valve 72 or a directional valve 73 to the line 11, 11 'of the main circuit which carries high pressure or low pressure, respectively.

Die Umschaltung der Rohrweiche 3 erfolgt über die vorzugsweise als Plungerzylinder ausgebildeten Hydrozylinder 21,21', die über die vom Hauptkreislauf abgezweigten Leitungen 22,22', das Umsteuerventil 30 und die Druckleitungen 23,23' direkt mit dem von der Reversierpumpe 6 geförderten Drucköl beaufschlagt werden. Die Vorsteuerung des Umsteuerventils 30 erfolgt bei dem gezeigten Ausführungsbeispiel hydraulisch über die Leitungen 24,24', die über die Wegeventile 31 und 40 mit dem Steuerdruck einer gemeinsam mit der Reversierpumpe 6 angetriebenen Hilfspumpe 25 beaufschlagbar sind. Das Wegeventil 31 ist dabei über die elektrisch oder gegebenenfalls auch hydraulisch abgegriffenen Endlagensignale x bzw. xx des Antriebszylinders 5 betätigbar, während das Wegeventil 40 nach Maßgabe des in den zum Stellzylinder 18 führenden Steuerleitungen 17,17' herrschenden Druckes über die Leitungen 28,28' umsteuerbar ist. Die Betätigung des die Förderrichtung der Reversierpumpe 6 bestimmenden Hauptsteuerventils 20 erfolgt über Endlagensignale der Rohrweichenzylinder 21,21', die über die Hydraulikleitungen 26,26' und/oder über elektrische Signalgeber y abgreifbar sind.The switchover of the pipe switch 3 takes place via the hydraulic cylinders 21, 21 ', which are preferably designed as plunger cylinders and which act directly on the pressure oil delivered by the reversing pump 6 via the lines 22, 22' branched off from the main circuit, the reversing valve 30 and the pressure lines 23, 23 ' will. In the exemplary embodiment shown, the pilot control of the reversing valve 30 takes place hydraulically via the lines 24, 24 ′, which via the directional valves 31 and 40 with the control pressure of one together with the reversing pump 6 driven auxiliary pump 25 can be acted upon. The directional control valve 31 can be actuated via the electrically or optionally also hydraulically tapped end position signals x or xx of the drive cylinder 5, while the directional control valve 40 according to the pressure prevailing in the control lines 17, 17 'leading to the actuating cylinder 18 via the lines 28, 28' is reversible. The main control valve 20, which determines the delivery direction of the reversing pump 6, is actuated via end position signals of the pipe switch cylinders 21, 21 ', which can be tapped via the hydraulic lines 26, 26' and / or via electrical signal transmitters y.

Die Hilfspumpe 25 lädt auch den geschlossenen Hauptkreis über die Rückschlagventile 75,75' auf und ist abgesichert durch das Druckbegrenzungsventil 74.The auxiliary pump 25 also charges the closed main circuit via the check valves 75, 75 'and is protected by the pressure relief valve 74.

Die gezeigte Schaltungsanordnung führt zu einer Folgesteuerung der Antriebszylinder 5,5' und der Rohrweichenzylinder 21,21', die wie folgt funktioniert:The circuit arrangement shown leads to a sequential control of the drive cylinders 5.5 'and the tubular switch cylinders 21.21', which functions as follows:

Wenn im Zuge eines Fördervorgangs beispielsweise die stangenseitige Endlage des Antriebskolbens 8 im Antriebszylinder 5 erreicht wird, wird über das elektrisch abgegriffene Endlagensignal x eine Umsteuerung des Wegeventils 31 ausgelöst. Dadurch wird das Umsteuerventil 30 unter Auslösung eines Umsteuervorgangs an den Rohrweichenzylindern 21,21' umgesteuert, wobei die Förderrichtung der Reversierpumpe 6 zunächst noch erhalten bleibt und die Antriebskolben 8,8' über das Drucköl in der Leitung 11 in ihrer jeweiligen Endlage gehalten werden. Wenn die Rohrweiche 3 ihre Endlage erreicht hat, wird über das entsprechende Endlagensignal das Ventil 20 umgesteuert. Dadurch wechselt die Vorsteuerung am Stellzylinder 18, so daß die Schrägscheibe 15 der Reversierpumpe 6 unter Umkehrung der Förderrichtung durchschwenkt. Das Umsteuersignal wird parallel dazu zwischen dem Ventil 20 und dem Stellzylinder 18 abgegriffen und über die Leitungen 28,28' auf die Vorsteuerung des Ventils 40 geschaltet. Das Ventil 40 wechselt damit seine Lage und sorgt so dafür, daß die Rohrweichenzylinder 21,21' die zuvor eingenommene Endstellung trotz der Förderrichtungsumkehr der Reversierpumpe 6 beibehalten. Da das Vorsteuerventil 40 auf das Umsteuersignal schneller reagiert als die Reversierpumpe 6, sind in den Vorsteuerleitungen 28,28' einstellbare Drosseln 29,29' angeordnet, die zur Vermeidung einer unerwünschten Rückschaltung der Rohrweichenzylinder 21,21' im Zuge der Förderrichtungsumkehr angepaßt an das Zeitverhalten der Reversierpumpe 6 ein langsames Durchschalten des Vorsteuerventils 40 und damit des Wegeventils 30 bewirken. Mittels des dem Umsteuerventil 20 vorgeschalteten Rückförderventils 32 in den Steuerleitungen 26,26' können bei Bedarf die Antriebszylinder 5,5' in entgegengesetzter Weise beaufschlagt werden, so daß Material aus der Förderleitung in den Vorratsbehälter zurückgefördert wird.If, for example, the rod-side end position of the drive piston 8 in the drive cylinder 5 is reached in the course of a conveying process, a reversal of the directional control valve 31 is triggered via the electrically tapped end position signal x. As a result, the reversing valve 30 is reversed while triggering a reversing process on the pipe switch cylinders 21, 21 ', the direction of delivery of the reversing pump 6 initially being retained and the drive piston 8, 8' over the Pressure oil in line 11 are kept in their respective end positions. When the diverter 3 has reached its end position, the valve 20 is reversed via the corresponding end position signal. As a result, the pilot control on the actuating cylinder 18 changes, so that the swash plate 15 of the reversing pump 6 swivels with reversal of the conveying direction. The reversal signal is tapped in parallel between the valve 20 and the actuating cylinder 18 and switched to the pilot control of the valve 40 via the lines 28, 28 '. The valve 40 thus changes its position and thus ensures that the tube switch cylinders 21, 21 'maintain the previously assumed end position despite the reversal of the direction of delivery of the reversing pump 6. Since the pilot valve 40 responds to the reversal signal faster than the reversing pump 6, adjustable throttles 29, 29 'are arranged in the pilot lines 28, 28', which are adapted to the time behavior in order to avoid an undesired downshift of the pipe switch cylinders 21, 21 'in the course of the reversal of the conveying direction the reversing pump 6 cause the pilot valve 40 and thus the directional control valve 30 to slowly switch through. By means of the return valve 32 upstream of the reversing valve 20 in the control lines 26, 26 ', the drive cylinders 5, 5' can be acted upon in the opposite manner if necessary, so that material is conveyed back from the delivery line into the storage container.

Die beschriebene Einkreis-Anordnung ist vor allem :ür kleinere bzw. langsam laufende Anlagen geeignet, bei denen es auf eine möglichst geringe Anzahl an hydraulischen Baugruppen ankommt. Für große, schnell laufende Maschinen bietet sich eine Zweikreis-Folgeschaltung an, bei der das Rohrweichen-Umsteuerventil 30 nicht über die Leitungen 22,22' an den Hauptkreislauf, sondern an einen getrennten Hydraulikkreislauf angeschlossen wird. Im letzteren Falle kann das Wegeventil 40 entfallen.The single-circuit arrangement described is above all: suitable for smaller or slow-running systems at who need the smallest possible number of hydraulic assemblies. For large, fast-running machines, a two-circuit sequential circuit is suitable, in which the diverter switch valve 30 is not connected to the main circuit via lines 22, 22 ', but to a separate hydraulic circuit. In the latter case, the directional control valve 40 can be omitted.

Claims (15)

  1. A method for controlling a thick matter pump with two feed cylinders which open trough front-side openings into a material feed tank and which can be operated in a push-pull manner by means of at least one hydraulic reversing pump and by hydraulic driving cylinders controlled by the reversing pump, with a hydraulically operable tube switch configured inside the material feed tank which is suitable for connection on the intake side alternately to each of the openings of the feed cylinder and which releases the opening of the other feed cylinder, and is suitable for connection on the output side to a delivery pipe, whereby at the end of each feed-cylinder compression stroke, a tube-switch reversing operation is initiated and during the reversing operation the delivery of thick matter is interrupted, and the direction of delivery of the reversing pump is retained while a free supply of pressurized oil to the driving cylinders is maintained, and the pistons of the driving cylinders are retained at end-stop positions under the effect of the pressure produced by the reversing pump in the main circuit, and whereby only at the end of the tube-switch reversing operation is the direction of delivery of the reversing pump reversed, characterized in that to switch over the tube switch, pressurized oil is tapped off directly from a main circuit which is free of valves and fittings and leads from the reversing pump to the driving cylinders.
  2. The method according to claim 1, characterized in that when the tube-switch reversing operation is initiated, the output volume and/or the feed pressure of the reversing pump is altered while the direction of delivery is retained.
  3. The method according to claim 1 or 2, characterized in that after each switch-over operation, a preferably hydraulic or electric end-position signal is tapped off at the tube switch or at its hydraulic actuating elements to initiate a reversal operation for the reversing pump.
  4. The method according to one of the claims 1 to 3, characterized in that when the reversal operation is initiated, the supply of pressurized oil to the tube-switch actuating elements is interrupted or reversed while compensating for the reversal of oil flow in the main circuit.
  5. The method according to one of the claims 1 to 4, characterized in that when the reversing operation is initiated, the reversing pump is tripped by force for a short time to a maximum output volume and is subsequently readjusted according to a defined output volume or feed pressure.
  6. The method according to one of the claims 1 to 5, characterized in that at least one additional reversing pump is optionally switched in a parallel connection into the main circuit.
  7. The method according to one of the claims 1 to 6, characterized in that during the delivery of thick matter, the hydraulic tube-switch actuating elements are retained at end-stop positions under the effect of the pressure produced by the reversing pump until a reversing operation is linitiated upon completion of the compression stroke, while the direction of delivery of the reversing pump is retained.
  8. A device for controlling a thick matter pump with two feed cylinders which open through front-side openings into a material feed tank and which can be operated in a push-pull manner by means of at least one hydraulic reversing pump and by hydraulic driving cylinders controlled by the reversing pump, with a hydraulically operable tube switch configured inside the material feed tank which is suitable for connection on the intake side alternately to each of the openings of the feed cylinder and which releases the opening of the other feed cylinder, and is suitable for connection on the output side to a delivery pipe, whereby at the end of each feed-cylinder compression stroke, a tube-switch reversing operation is initiated and whereby during the reversing operation the delivery of thick matter can be interrupted, and the free supply of pressurized oil to the driving cylinders can be maintained during the reversing operation, while retaining the previous direction of delivery of the reversing pump, and whereby at the end of each switch-over operation, an end-position signal can be tapped off at the tube switch or at its hydraulic actuating elements to initiate a reversal operation for the reversing pump, characterized in that the hydraulic actuating elements (21,21') of the tube switch (3) can be charged with the pressurized oil tapped off from the main circuit (11,11'), which leads from the reversing pump (6) to the driving cylinders (5,5') and is free of valves and fittings.
  9. The device according to claim 8, characterized in that the output volume and/or the feed pressure of the reversing pump (6) is adjustable during the delivery of thick matter, on the one hand, and during the reversing operation, on the other hand, to various set-point values.
  10. The device according to claims 8 or 9 with a controlling and/or regulating mechanism (18) for the reversing pump (6) preferably featuring a diverter valve (20) with pilot control for adjusting the direction of delivery, characterized in that the controlling and/or regulating mechanism (18), preferably the precontrol of its diverter valve (20), are able to receive hydraulic or electric end-position signals (y) which are adapted to be tapped off at the tube switch (3) or at its hydraulic actuating elements (21,21').
  11. The device according to claim 10, characterized in that an inversion element (32), which responds to a return-delivery signal and which reverses the direction of delivery of the reversing pump (6), is configured in the circuit arrangement (26,26') which transmits the hydraulic or electric end-position signals.
  12. The device according to one of the claims 8 to 11, characterized in that a diverter valve (30), which reverses the direction of the pressurized oil supply, is configured in the hydraulic lines (22,22') which branch off from the main circuit (11,11') and lead to the hydraulic actuating elements (21,21') of the tube switch (3) and said diverter valve (30) can be actuated by means of a pilot valve (40) which responds to the direction of delivery of the reversing pump (6).
  13. The device according to claim 12, characterized in that the pilot valve (40) is operable by means of a restrictor or delay circuit arrangement (29,29') which is adaptable to the time response of the reversing-pump reversal operation.
  14. The device according to claim 12 or 13, characterized in that an additional diverter valve (31), which is operable by end-position signals (x,xx) from the feed cylinders (1,1') or from their driving cylinders (5,5'), is configured in the pilot lines (24,24') leading to the diverter valve (30).
  15. The device according to one of the claims 8 to 14, characterized by a circuit arrangement (16,PS), which responds to end-position signals (x,xx;y) of the feed cylinders (1,1') and of the tube switch (3) and is connected to the controlling and/or regulating mechanism (18) of the reversing pump, for altering the output volume and/or the feed pressure of the reversing pump (6).
EP89908162A 1988-12-05 1989-07-11 Process and device for control of a twin-cylinder thick matter pump Expired - Lifetime EP0446206B1 (en)

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DE3840892 1988-12-05
DE3840892A DE3840892A1 (en) 1988-12-05 1988-12-05 METHOD AND DEVICE FOR CONTROLLING A TWO-CYLINDER FUEL PUMP

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EP0446206B1 true EP0446206B1 (en) 1993-06-16

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JP (1) JPH04501897A (en)
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DE58904753D1 (en) 1993-07-22
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WO1990006444A1 (en) 1990-06-14
JPH04501897A (en) 1992-04-02
US5344290A (en) 1994-09-06

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