EP0465474B1 - Control arrangement for a two-cylinder pump for thick materials - Google Patents

Control arrangement for a two-cylinder pump for thick materials Download PDF

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Publication number
EP0465474B1
EP0465474B1 EP90903351A EP90903351A EP0465474B1 EP 0465474 B1 EP0465474 B1 EP 0465474B1 EP 90903351 A EP90903351 A EP 90903351A EP 90903351 A EP90903351 A EP 90903351A EP 0465474 B1 EP0465474 B1 EP 0465474B1
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EP
European Patent Office
Prior art keywords
control
control arrangement
pressure
arrangement according
signal
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
Application number
EP90903351A
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German (de)
French (fr)
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EP0465474A1 (en
Inventor
Hartmut Benckert
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Putzmeister Concrete Pumps GmbH
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Putzmeister Werk Maschinenfabrik GmbH
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Publication of EP0465474A1 publication Critical patent/EP0465474A1/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
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B15/00—Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts
    • F04B15/02—Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts the fluids being viscous or non-homogeneous
    • F04B15/023—Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts the fluids being viscous or non-homogeneous supply of fluid to the pump by gravity through a hopper, e.g. without intake valve
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28C7/00—Controlling the operation of apparatus for producing mixtures of clay or cement with other substances; Supplying or proportioning the ingredients for mixing clay or cement with other substances; Discharging the mixture
    • B28C7/16—Discharge means, e.g. with intermediate storage of fresh concrete
    • B28C7/162—Discharge means, e.g. with intermediate storage of fresh concrete by means of conveyors, other than those comprising skips or containers, e.g. endless belts, screws, air under pressure
    • B28C7/163—Discharge means, e.g. with intermediate storage of fresh concrete by means of conveyors, other than those comprising skips or containers, e.g. endless belts, screws, air under pressure using a pump
    • 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
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S417/00—Pumps
    • Y10S417/90—Slurry pumps, e.g. concrete

Definitions

  • the invention relates to a control arrangement for a two-cylinder slurry pump with at least one hydraulic pump that can be adjusted in terms of its delivery rate by a preset signal, with two delivery cylinders that communicate with a material feed tank and are actuated by the hydraulic pump in push-pull mode, with one feed cylinder alternately with the material feed tank and one Conveying line connecting, operated by a hydraulic reversing mechanism, preferably designed as a pipe switch steering arrangement for the material flow, with a sensing device responsive to the end of each pressure stroke of the drive and / or delivery cylinder, at the output of which a triggering process triggering the steering arrangement can be tapped, and with a switching element connected on the output side to a delivery rate controller of the hydraulic pump, which switches one with the end position signals or with the end position signals Signal conversion derived control signals applied control input and at least two switch positions adjustable by the signal level at the control input for controlling different default signals on the flow rate controller.
  • a switching element is provided on the output side which is connected to the delivery rate controller of the hydraulic pump and which controls the hydraulic pump to the maximum delivery rate after reversing the direction of stroke in the drive and delivery cylinders.
  • This is intended to fill the delivery gap that arises when the pipe switch is reversed and to achieve a largely uniform flow of material to be conveyed at the end of the delivery line.
  • it is considered disadvantageous that the reversal of the pipe switch is triggered simultaneously with the reversal of stroke in the delivery cylinders via a reversing mechanism which can be actuated independently of the hydraulic pump. An additional hydraulic pump is required for this. The same has already been proposed in the earlier unpublished WO 89/11037.
  • the invention has for its object to provide a control arrangement for two-cylinder thick matter pumps with which the delivery volume of the hydraulic pump can be optimally adapted to the current requirements in the course of a delivery and changeover cycle in a single-circuit arrangement.
  • the inventive solution is based on the knowledge that an oil quantity that is independent of the oil quantity for the delivery stroke is required during the switching time of the steering arrangement. For single-circuit arrangements, there is therefore a need to adapt the delivery volume of the hydraulic pump to the respective operating state.
  • the drive cylinders and the hydraulic reversing mechanism of the steering arrangement can be actuated alternately with pressure oil from the same hydraulic pump via a sequence control, and that the delivery rate regulator of the hydraulic pump is acted upon by independent preset signals during the lifting phase of the drive cylinders and the reversing process of the reversing mechanism, the reversing of the stroke in the drive cylinders is triggered at the end of each reversing process of the steering arrangement.
  • the default signals can have a functional dependency which can be selected in accordance with the switching position of the switching element, depending on the operating parameters of the two-cylinder thick matter pump, in particular the hydraulic pump can be varied from the delivery volume and delivery pressure of the hydraulic pump.
  • a signal converter is arranged in front of the control input of the switching element and can be acted upon on the input side with the end position signal which essentially forms a square-wave signal, the output signal of which has a trailing edge which is adjustable with respect to the input signal.
  • the hydraulic pump first acts on the thick column to be pushed with a predetermined delivery rate, which leads to a predetermined acceleration of the column and to a pre-compression of the material contained therein.
  • the input and output signals of the signal converter essentially coincide in time in their front edges, so that the pipe switch is reversed largely without delay immediately after the completion of each pressure stroke.
  • the signal converter advantageously has a time delay element which responds to the trailing edge of the end position signal, preferably with an adjustable delay time.
  • The, for example, hydraulically designed signal converter can have an adjustable throttle and a check valve connected in parallel with the throttle and opening from the scanning device to the control input.
  • a time delay circuit which responds to the trailing edge of the electrical end position signal can be provided, which has, for example, an adjustable digital counter or an adjustable RC element as the time delay element.
  • the switching element is designed as a directional valve, which is an electrical, hydraulic or pneumatic Actuatable pilot valve as a control input, has at least two selection connections which can be set to different pressures and a working connection which is connected to the regulator for the hydraulic pump and can optionally be connected to one of the selection connections. At least one of the selection connections can expediently be acted upon with a variably adjustable default signal.
  • the directional control valve can be reversed between at least two control lines arranged on the side of the selection connections and equipped with throttles, pressure-maintaining valves and / or pressure-limiting valves.
  • the directional control valve can be reversed between at least two parallel strands of a throttle chain arranged on the side of the selection connections, an adjusting throttle being arranged in at least one of the parallel strands.
  • the control lines or throttle chains can preferably be supplied with a predetermined control pressure via an auxiliary pump.
  • further switching functions can be triggered via the switching element in the course of the reversal process triggered by the end position signals. For example, depending on the switching position of the switching element, high pressure limits or torque limits adapted to the respective needs can be carried out by correspondingly influencing the preset signals.
  • the thick matter pump essentially consists of two delivery cylinders 1, 1 ', the front 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 during the pressure stroke.
  • the feed 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 'with the pistons 8,8' of the drive cylinders 5,5 ' are common Piston rod 9,9 'connected.
  • 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 pistons 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 reversing device and swivels through the zero position and thus the delivery direction of the pressure oil in the lines 11, 11 '. of the main circuit in the free flow changes.
  • 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 swashplate 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 is determined in accordance with the switching states of the Thick matter pump varies with the means explained below.
  • pressure regulators 70 and 71 are provided, the control inputs of which can be connected via a shuttle valve 72 or a directional control valve 73 to the line 11, 11 'of the main circuit which carries high and 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 is carried out hydraulically via the lines 24, 24 ′, which can be acted on by the directional valves 21 and 40 with the control pressure of an auxiliary pump 25 that is driven together with the reversing pump 6.
  • 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 directional 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 valve 40 can be reversed in accordance with the pressure prevailing in the control lines 17, 17 'leading to the actuating cylinder 18.
  • 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 control pressure p s with which the delivery rate controller 18 of the hydraulic pump 6 is controlled, is automatically adjusted according to the switching states of the thick matter pump by a circuit arrangement designed as a throttle chain in the exemplary embodiment shown, via a directional control valve 61 (FIGS. 1 and 2) or 60 (FIG. 3) set.
  • the throttle chain is subjected to low pressure ND on the side of the pre-throttle 69 via the auxiliary pump 25 and is connected to the tank 100 on the side of the adjusting throttles 65 and 125 arranged in parallel lines.
  • the full low pressure ND is tapped as the control pressure p s because of the lack of pressure drop at the throttle 69, so that the main pump 6 is controlled by the regulator 18 to the full swivel angle.
  • the directional control valve 61 (or 60) is in its spring-centered position, in which the passage to the adjustment throttle 125 is open and the pressure oil flows from the fixed throttle 69 via the adjustment throttle 125 towards the tank. This results in a pressure drop, on the basis of which the control pressure p s adjusts to a value (control specification p 1) which is less than the low pressure ND.
  • the main pump 6 is accordingly adjusted via the controller 18 to a new swivel angle proportional to the control pressure p s , which corresponds to the desired delivery rate in the stroke phase.
  • an end position signal x or xx is tapped via an electrical or hydraulic scanning device in the area of the drive cylinder 5 and is applied to the electromagnetic or hydraulic pilot control input of the directional control valve 61 or 60 via an electrical or hydraulic signal converter 63 or 62.
  • a new control pressure p s which is higher or lower depending on the requirements, is set for controlling the delivery rate regulator 18. While the leading edge of the end position signal x or xx tapped at the drive cylinder 5 leads to the reversal of the directional control valve 61 or 60 almost without a time delay (in the hydraulic case according to FIG. 3 this is ensured by the check valve 64), occurs at the end of the switchover phase and thus at the beginning of the new delivery stroke, a delay in the changeover of the directional control valve 61 or 60 occurs via the delay element 63 or 62 (in the case of FIG. 3 caused by the adjusting throttle 66).
  • the reversing pump 6 in the main circuit initially acts on the thick matter column to be pushed with the previously set delivery rate, which is the case, for example, with a previously set higher level Delivery rate for a brief acceleration of the thick matter column and for a pre-compression of the one inside Leads.
  • a high-pressure limiting valve 82 is also arranged, which enables the maximum high pressure to be adjusted during the changeover phase with a time delay.
  • the limiting valve 82 lowers the control pressure between the throttle 69 and the adjusting throttle 65, so that the main pump 6 can be pivoted back to a correspondingly lower delivery rate, in particular to the delivery rate 0.
  • 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:
  • the reversing valve 30 is reversed by triggering a reversing process on the tubular switch cylinders 21, 21 ', the conveying direction of the reversing pump 6 initially being retained and the drive pistons 8, 8 'are held in their respective end positions via the pressure oil in line 11.
  • 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 directional control valve 61 (or 60) is switched with a time delay via the delay element 63 (or 62), the delivery rate of the hydraulic pump 6 is first determined by the throttle chain 69, 65 (control specification p2) and only after the delay time has elapsed to Choke chain 69, 125 defined value (control specification p 1) switched.
  • 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.
  • 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.
  • 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 material feed container.
  • the high-pressure limiting valve 70 is effective in the spring-centered position of the directional control valve 61, while in the switched position of the valve 61, the high pressure relief valve 82 is connected in parallel. Therefore, only a lower pressure limit value can be set at the pressure limiting valve 82 than at the valve 70, which is equivalent to the fact that in the controlled position of the valve 61 only a lower limiting pressure can be set than in the spring-centered position of this valve.
  • valve 70 is placed in one of the selection-side control lines of the shuttle valve 61, so that the setting of the limiting pressure in both switching positions can take place independently of one another.
  • control valves 200 and 300 are arranged in the two control lines, the control inputs of which are connected via the shuttle valve 72 to the high-pressure side of the hydraulic pump 6 and which control the set pressure p 1 or p 2 at the input in accordance with a hyberbolic dependency of high pressure and flow rate (set value p 1, p2) adjust.
  • a torque limitation for the drive motor of the pump 6 can thus be adjusted to the requirements during the conveying process and during the switching process.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Reciprocating Pumps (AREA)

Abstract

A servo control for a two-cylinder pump for thick materials comprises two delivery cylinders (1, 1') which open through front-face openings (2, 2') into a material dispenser container in which a hydraulically operated shunt pipe (3) is arranged. On the inlet side, the shunt pipe (3) can be connected alternately to the openings (2, 2') of the delivery cylinders (1, 1'), freeing the other opening, and on the outlet side it can be connected to a delivery line (4). The delivery cylinders (1, 1') are connected to hydraulic drive cylinders (5, 5') which are actuated by at least one push-pull hydropump (6). At the end of each pressure stroke in the delivery cylinders (1, 1'), a reversal process of the shunt pipe (3) is initiated. The delivery volume of the hydropump (6) is varied automatically in accordance with the switching states inside the pump for thick materials by the use of a switching element.

Description

Die Erfindung betrifft eine Steuerungsanordnung für eine Zweizylinder-Dickstoffpumpe mit mindestens einer durch ein Vorgabesignal in ihrer Fördermenge einstellbaren Hydropumpe, mit zwei mit einem Materialaufgabebehälter kommunizierenden, mittels durch die Hydropumpe gesteuerter Antriebszylinder im Gegentakt betätigbaren Förderzylindern, mit einer die Förderzylinder abwechselnd mit dem Materialaufgabebehälter und einer Förderleitung verbindenden, durch einen hydraulischen Umsteuermechanismus betätigbaren, vorzugsweise als Rohrweiche ausgebildeten Lenkanordnung für den Materialfluß, mit einer auf das Ende eines jeden Druckhubs der Antriebs- und/ oder Förderzylinder ansprechenden Abtasteinrichtung, an deren Ausgang ein einen Umsteuervorgang der Lenkanordnung auslösendes Endlagensignal zu abgreifbar ist, und mit einem ausgangsseitig mit einem Fördermengenregler der Hydropumpe verbundenen Schaltelement, das einen mit den Endlagensignalen oder mit aus den Endlagensignalen durch Signalumformung abgeleiteten Steuersignalen beaufschlagten Steuereingang sowie mindestens zwei durch den Signalpegel am Steuereingang einstellbare Schaltstellungen zur Durchsteuerung unterschiedlicher Vorgabesignale auf den Fördermengenregler aufweist.The invention relates to a control arrangement for a two-cylinder slurry pump with at least one hydraulic pump that can be adjusted in terms of its delivery rate by a preset signal, with two delivery cylinders that communicate with a material feed tank and are actuated by the hydraulic pump in push-pull mode, with one feed cylinder alternately with the material feed tank and one Conveying line connecting, operated by a hydraulic reversing mechanism, preferably designed as a pipe switch steering arrangement for the material flow, with a sensing device responsive to the end of each pressure stroke of the drive and / or delivery cylinder, at the output of which a triggering process triggering the steering arrangement can be tapped, and with a switching element connected on the output side to a delivery rate controller of the hydraulic pump, which switches one with the end position signals or with the end position signals Signal conversion derived control signals applied control input and at least two switch positions adjustable by the signal level at the control input for controlling different default signals on the flow rate controller.

Bei einer bekannten Steuerungsanordnung dieser Art (DE-A-3 243 738), ist ein ausgangseitig mit dem Fördermengenregler der Hydropumpe verbundenes Schaltelement vorgesehen, das nach Umkehr der Hubrichtung in den Antriebs- und Förderzylindern die Hydropumpe auf maximale Fördermenge durchsteuert. Dadurch soll die bei der Umsteuerung der Rohrweiche entstehende Förderlücke ausgefüllt und ein weitgehend gleichmäßiger Fördergutstrom am Ende der Förderleitung erzielt werden. Bei der bekannten Anordnung wird als nachteilig angesehen, daß die Umsteuerung der Rohrweiche gleichzeitig mit der Hubumkehr in den Förderzylindern über einen von der Hydropumpe unabhängig betätigbaren Umsteuermechanismus ausgelöst wird. Dazu ist eine zusätzliche Hydraulikpumpe erforderlich. Entsprechendes wurde auch bereits in der prioritätsälteren, unveröffentlichten WO 89/11037 vorgeschlagen.In a known control arrangement of this type (DE-A-3 243 738), a switching element is provided on the output side which is connected to the delivery rate controller of the hydraulic pump and which controls the hydraulic pump to the maximum delivery rate after reversing the direction of stroke in the drive and delivery cylinders. This is intended to fill the delivery gap that arises when the pipe switch is reversed and to achieve a largely uniform flow of material to be conveyed at the end of the delivery line. In the known arrangement, it is considered disadvantageous that the reversal of the pipe switch is triggered simultaneously with the reversal of stroke in the delivery cylinders via a reversing mechanism which can be actuated independently of the hydraulic pump. An additional hydraulic pump is required for this. The same has already been proposed in the earlier unpublished WO 89/11037.

Ausgehend hiervon liegt der Erfindung die Aufgabe zugrunde, eine Steuerungsanordnung für Zweizylinder-Dickstoffpumpen zu schaffen, mit der in einer Einkreisanordnung das Fördervolumen der Hydropumpe im Verlauf eines Förder- und Umschaltzyklus an die augenblicklichen Anforderungen optimal angepaßt werden kann.Proceeding from this, the invention has for its object to provide a control arrangement for two-cylinder thick matter pumps with which the delivery volume of the hydraulic pump can be optimally adapted to the current requirements in the course of a delivery and changeover cycle in a single-circuit arrangement.

Die erfinderische Lösung geht von der Erkenntnis aus, daß während der Umschaltzeit der Lenkanordnung eine von der Ölmenge für den Förderhub unabhängige Ölmenge benötigt wird. Für Einkreis-Anordnungen besteht also ein Bedürfnis nach einer Anpassung des Fördervolumens der Hydropumpe an den jeweiligen Betriebszustand. Um dies zu erreichen, wird gemäß der Erfindung vorgeschlagen, daß die Antriebszylinder und der hydraulische Umsteuermechanismus der Lenkanordnung über eine Folgesteuerung abwechselnd mit Drucköl aus der gleichen Hydropumpe betätigbar sind, und daß der Fördermengenregler der Hydropumpe wahrend der Hubphase der Antriebszylinder und des Umsteuervorgangs des Umsteuermechanismus mit voneinander unabhängigen Vorgabesignalen beaufschlagt wird, wobei die Hubumkehr in den Antriebszylindern am Ende eines jeden Umsteuervorgangs der Lenkanordnung ausgelöst wird.The inventive solution is based on the knowledge that an oil quantity that is independent of the oil quantity for the delivery stroke is required during the switching time of the steering arrangement. For single-circuit arrangements, there is therefore a need to adapt the delivery volume of the hydraulic pump to the respective operating state. To achieve this, it is proposed according to the invention that the drive cylinders and the hydraulic reversing mechanism of the steering arrangement can be actuated alternately with pressure oil from the same hydraulic pump via a sequence control, and that the delivery rate regulator of the hydraulic pump is acted upon by independent preset signals during the lifting phase of the drive cylinders and the reversing process of the reversing mechanism, the reversing of the stroke in the drive cylinders is triggered at the end of each reversing process of the steering arrangement.

Gemäß einer bevorzugten Ausgestaltung der Erfindung können die Vorgabesignale eine nach Maßgabe der Schaltstellung des Schaltelements auswählbare funktionelle Abhängigkeit von Betriebsparametern der Zweizylinder-Dickstoffpumpe, insbesondere der Hydropumpe aufweisen Beispielsweise können die Vorgabesignale in Abhängigkeit von einem vorgegebenen maximalen Förderdruck oder in Abhängigkeit von einem vorgegebenen Maximalwert des Produkts aus Fördermenge und Förderdruck der Hydropumpe variiert werden.According to a preferred embodiment of the invention, the default signals can have a functional dependency which can be selected in accordance with the switching position of the switching element, depending on the operating parameters of the two-cylinder thick matter pump, in particular the hydraulic pump can be varied from the delivery volume and delivery pressure of the hydraulic pump.

Gemäß einer bevorzugten Ausgestaltung der Erfindung ist vor dem Steuereingang des Schaltelements ein eingangsseitig mit dem im wesentlichen ein Rechtecksignal bildenden Endlagensignal beaufschlagbarer Signalumformer angeordnet, dessen Ausgangssignal eine gegenüber dem Eingangssignal einstellbar nacheilende Rückflanke aufweist. Damit soll erreicht werden, daß nach der Umsteuerung der Rohrweiche und der darauf folgenden Umsteuerung der Förderrichtung in den Förderzylindern die Hydropumpe zunächst mit vorgegebener Fördermenge auf die anzuschiebende Dickstoffsäule einwirkt, was zu einer vorgegebenen Beschleunigung der Säule und zu einer Vorverdichtung des darin befindlichen Materials führt. Andererseits fallen die Ein- und Ausgangssignale des Signalumformers in ihren Vorderflanken zeitlich im wesentlichen zusammen, so daß unmittelbar nach Beendigung eines jeden Druckhubs die Rohrweiche weitgehend verzögerungsfrei umgesteuert wird.According to a preferred embodiment of the invention, a signal converter is arranged in front of the control input of the switching element and can be acted upon on the input side with the end position signal which essentially forms a square-wave signal, the output signal of which has a trailing edge which is adjustable with respect to the input signal. This is intended to ensure that after reversing the pipe switch and then reversing the conveying direction in the conveying cylinders, the hydraulic pump first acts on the thick column to be pushed with a predetermined delivery rate, which leads to a predetermined acceleration of the column and to a pre-compression of the material contained therein. On the other hand, the input and output signals of the signal converter essentially coincide in time in their front edges, so that the pipe switch is reversed largely without delay immediately after the completion of each pressure stroke.

Vorteilhafterweise weist der Signalumformer ein auf die Rückflanke des Endlagensignals ansprechendes Zeitverzögerungsglied vorzugsweise mit einstellbarer Verzögerungszeit auf. Der beispielsweise hydraulisch ausgebildete Signalumformer kann dabei eine einstellbare Drossel und ein zur Drossel parallel geschaltetes, von der Abtasteinrichtung zum Steuereingang hin öffnendes Rückschlagventil aufweisen. Im Falle eines elektrischen Signalumformers kann eine auf die Rückflanke des elektrischen Endlagensignals ansprechende Zeitverzögerungsschaltung vorgesehen werden, die beispielsweise einen einstellbaren Digitalzähler oder ein einstellbares RC-Glied als Zeitverzögerungsglied aufweist.The signal converter advantageously has a time delay element which responds to the trailing edge of the end position signal, preferably with an adjustable delay time. The, for example, hydraulically designed signal converter can have an adjustable throttle and a check valve connected in parallel with the throttle and opening from the scanning device to the control input. In the case of an electrical signal converter, a time delay circuit which responds to the trailing edge of the electrical end position signal can be provided, which has, for example, an adjustable digital counter or an adjustable RC element as the time delay element.

Gemäß einer weiteren bevorzugten Ausgestaltung der Erfindung ist das Schaltelement als Wegeventil ausgebildet, das ein elektrisch, hydraulisch oder pneumatisch betätigbares Vorsteuerventil als Steuereingang, mindestens zwei auf unterschiedliche Drücke einstellbare Auswahlanschlüsse und einen mit dem Regler für die Hydropumpe verbundenen, wahlweise mit einem der Auswahlanschlüsse verbindbaren Arbeitsanschluß aufweist. Zweckmäßig ist dabei mindestens einer der Auswahlanschlüsse mit einem variabel einstellbaren Vorgabesignal beaufschlagbar.According to a further preferred embodiment of the invention, the switching element is designed as a directional valve, which is an electrical, hydraulic or pneumatic Actuatable pilot valve as a control input, has at least two selection connections which can be set to different pressures and a working connection which is connected to the regulator for the hydraulic pump and can optionally be connected to one of the selection connections. At least one of the selection connections can expediently be acted upon with a variably adjustable default signal.

Gemäß einer weiteren bevorzugten Ausgestaltung der Erfindung ist das Wegeventil zwischen mindestens zwei auf der Seite der Auswahlanschlüsse angeordneten, mit Drosseln, Druckhalteventilen und/oder Druckbegrenzungsventilen bestückten Steuersträngen umsteuerbar. Insbesondere kann das Wegeventil zwischen mindestens zwei auf der Seite der Auswahlanschlüsse angeordneten Parallelsträngen einer Drosselkette umgesteuert werden, wobei in mindestens einem der Parallelstränge eine Einstelldrossel angeordnet ist. Die Steuerstränge bzw. Drosselketten können vorzugsweise über eine Hilfspumpe mit einem vorgegebenen Steuerdruck beaufschlagt werden. Weiter können über das Schaltelement im Zuge des durch die Endlagensignale ausgelösten Umsteuervorgangs weitere Schaltfunktionen ausgelöst werden. So können beispielsweise nach Maßgabe der Schaltstellung des Schaltelements den jeweiligen Bedürfnissen angepaßte Hochdruckbegrenzungen oder Drehmomentbegrenzungen durch entsprechende Beeinflussung der Vorgabesignale vorgenommen werden.According to a further preferred embodiment of the invention, the directional control valve can be reversed between at least two control lines arranged on the side of the selection connections and equipped with throttles, pressure-maintaining valves and / or pressure-limiting valves. In particular, the directional control valve can be reversed between at least two parallel strands of a throttle chain arranged on the side of the selection connections, an adjusting throttle being arranged in at least one of the parallel strands. The control lines or throttle chains can preferably be supplied with a predetermined control pressure via an auxiliary pump. Furthermore, further switching functions can be triggered via the switching element in the course of the reversal process triggered by the end position signals. For example, depending on the switching position of the switching element, high pressure limits or torque limits adapted to the respective needs can be carried out by correspondingly influencing the preset signals.

Im folgenden wird die Erfindung anhand einiger in der Zeichnung in schematischer Weise dargestellter Ausführungsbeispiele näher erläutert. Es zeigen

  • Fig. 1 einen Schaltplan einer Steuerungsanordnung für eine Zweizylinder-Dickstoffpumpe mit einer Freifluß-Folgesteuerung von Antriebszylindern und Rohrweichenzylindern in Einkreisanordnung;
  • Fig. 2 ein Schaltelement zur Fördermengensteuerung mit elektrischem Zeitverzögerungsglied;
  • Fig. 3 ein Schaltelement zur Fördermengensteuerung mit hydraulischem Zeitverzögerungsglied;
  • Fig. 4 einen Schaltplan einer Steuerungsanordnung entsprechend Fig. 1 mit zusätzlichen Schaltfunktionen.
The invention is explained in more detail below with reference to some exemplary embodiments shown in the drawing in a schematic manner. Show it
  • Figure 1 is a circuit diagram of a control arrangement for a two-cylinder thick matter pump with a free-flow sequence control of drive cylinders and pipe switch cylinders in a single circuit arrangement.
  • 2 shows a switching element for controlling the delivery rate with an electrical time delay element;
  • 3 shows a switching element for controlling the delivery rate with a hydraulic time delay element;
  • Fig. 4 is a circuit diagram of a control arrangement corresponding to FIG. 1 with additional switching functions.

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 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 front 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 during the pressure stroke. The feed 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 'with the pistons 8,8' of the drive cylinders 5,5 'are common Piston rod 9,9 'connected. 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 Umsteuerorgan durch die Null-Lage hindurchschwenkt und damit die Förderrichtung des Drucköls 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 wird nach Maßgabe der Schaltzustände der Dickstoffpumpe mit den weiter unten erläuterten Mitteln variiert. 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 pistons 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 reversing device and swivels through the zero position and thus the delivery direction of the pressure oil in the lines 11, 11 '. of the main circuit in the free flow changes. 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 swashplate 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 is determined in accordance with the switching states of the Thick matter pump varies with the means explained below. To adjust 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 control valve 73 to the line 11, 11 'of the main circuit which carries high and 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 21 und 40 mit dem Steuerdruck einer gemeinsam mit der Reversierpumpe 6 angetriebenen Hilfspumpe 25 beaufschlagbar sind. Die Hilfspumpe 25 lädt auch den geschlossenen Hauptkreis über die Rückschlagventile 75,75' auf und ist abgesichert durch das Druckbegrenzungsventil 74. Das Wegeventil 31 ist 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 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 is carried out hydraulically via the lines 24, 24 ′, which can be acted on by the directional valves 21 and 40 with the control pressure of an auxiliary pump 25 that is driven together with the reversing pump 6. 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 directional 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 valve 40 can be reversed in accordance with the pressure prevailing in the control lines 17, 17 'leading to the actuating cylinder 18. 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.

Der Steuerdruck ps, mit dem der Fördermengenregler 18 der Hydropumpe 6 angesteuert wird, wird nach Maßgabe der Schaltzustände der Dickstoffpumpe automatisch durch eine im gezeigten Ausführungsbeispiel als Drosselkette ausgebildete Schaltungsanordnung über ein Wegeventil 61 (Fig. 1 und 2) bzw. 60 (Fig. 3) eingestellt. Die Drosselkette wird auf der Seite der Vordrossel 69 über die Hilfspumpe 25 mit Niederdruck ND beaufschlagt und ist auf der Seite der in Parallelsträngen angeordneten Verstelldrosseln 65 und 125 mit dem Tank 100 verbunden. Wird die Druckölströmung an der Drossel 125 unterbrochen, so wird wegen des fehlenden Druckabfalls an der Drossel 69 der volle Niederdruck ND als Steuerdruck ps abgegriffen, so daß die Hauptpumpe 6 über den Regler 18 auf den vollen Schwenkwinkel durchgesteuert wird. Während des Förderhubs befindet sich das Wegeventil 61 (bzw. 60) in seiner federzentrierten Stellung, in der der Durchgang zur Verstelldrossel 125 geöffnet ist und das Drucköl von der Festdrossel 69 über die Verstelldrossel 125 in Richtung Tank abfließt. Dadurch ergibt sich ein Druckgefälle, aufgrund dessen der Steuerdruck ps sich auf einen Wert (Regelvorgabe p₁) einstellt, der kleiner als der Niederdruck ND ist. Die Hauptpumpe 6 wird dementsprechend über den Regler 18 auf einen neuen, zum Steuerdruck ps proportionalen Schwenkwinkel eingeregelt, der der gewünschten Fördermenge in der Hubphase entspricht. Am Ende eines jeden Förderhubs wird über eine elektrische oder hydraulische Abtasteinrichtung im Bereich des Antriebszylinders 5 jeweils ein Endlagensignal x bzw. xx abgegriffen und über einen elektrischen oder hydraulischen Signalumformer 63 bzw. 62 auf den elektromagnetischen bzw. hydraulischen Vorsteuereingang des Wegeventils 61 bzw. 60 gelegt. Dadurch wird nun der Steuerdruck ps = p₂ durch die Drosselkette zwischen der Vordrossel 69 und der Verstelldrossel 65 (Regelvorgabe p₂) eingestellt. Während der Umsteuerphase der Rohrweiche wird also ein neuer, je nach Anforderungen höherer oder niedrigerer Steuerdruck ps zur Ansteuerung des Fördermengenreglers 18 eingestellt. Während die Vorderflanke des am Antriebszylinder 5 abgegriffenen Endlagensignals x bzw. xx nahezu ohne zeitliche Verzögerung zur Umsteuerung des Wegeventils 61 bzw. 60 führt (im hydraulischen Fall gemäß Fig. 3 wird dies durch das Rückschlagventil 64 gewährleistet), tritt am Ende der Umschaltphase und damit zu Beginn des neuen Förderhubs über das Verzögerungsglied 63 bzw. 62 eine Verzögerung der Umschaltung des Wegeventils 61 bzw. 60 ein (im Falle der Fig. 3 verursacht durch die Verstelldrossel 66). Dadurch wird erreicht, daß nach der Umsteuerung der Rohrweiche 3 und der darauf folgenden Umsteuerung der Förderrichtung in den Förderzylindern 5,5', die Reversierpumpe 6 im Hauptkreislauf zunächst mit der zuvor eingestellten Fördermenge auf die anzuschiebende Dickstoffsäule einwirkt, was z.B. bei einer zuvor höher eingestellten Fördermenge zu einer kurzzeitigen Beschleunigung der Dickstoffsäule und zu einer Vorverdichtung des darin befindlichen Materials führt. Auf der Seite der Einstelldrossel 65 der Drosselkette ist ferner ein Hochdruck-Begrenzungsventil 82 angeordnet, das eine Verstellung des maximalen Hochdrucks während der Umschaltphase mit Zeitverzögerung ermöglicht. Im Hochdruckfall senkt das Begrenzungsventil 82 den Steuerdruck zwischen der Drossel 69 und der Verstelldrossel 65 ab, so daß die Hauptpumpe 6 auf eine entsprechend niedrigere Fördermenge, insbesondere auf die Fördermenge 0 zurückgeschwenkt werden kann. In einem weiteren Strang der Drosselkette befindet sich ein extern ansteuerbares Umschaltventil 68, das in der federzentrierten Stellung gesperrt ist und in der durchgeschalteten Stellung hinter der Drossel 69 einen unmittelbaren Abfluß zum Tank bildet, so daß über den Steuerdruck ps = 0 die Hydropumpe 6 auf Fördermenge 0 geschaltet werden kann.The control pressure p s , with which the delivery rate controller 18 of the hydraulic pump 6 is controlled, is automatically adjusted according to the switching states of the thick matter pump by a circuit arrangement designed as a throttle chain in the exemplary embodiment shown, via a directional control valve 61 (FIGS. 1 and 2) or 60 (FIG. 3) set. The throttle chain is subjected to low pressure ND on the side of the pre-throttle 69 via the auxiliary pump 25 and is connected to the tank 100 on the side of the adjusting throttles 65 and 125 arranged in parallel lines. If the pressure oil flow at the throttle 125 is interrupted, the full low pressure ND is tapped as the control pressure p s because of the lack of pressure drop at the throttle 69, so that the main pump 6 is controlled by the regulator 18 to the full swivel angle. During the delivery stroke, the directional control valve 61 (or 60) is in its spring-centered position, in which the passage to the adjustment throttle 125 is open and the pressure oil flows from the fixed throttle 69 via the adjustment throttle 125 towards the tank. This results in a pressure drop, on the basis of which the control pressure p s adjusts to a value (control specification p 1) which is less than the low pressure ND. The main pump 6 is accordingly adjusted via the controller 18 to a new swivel angle proportional to the control pressure p s , which corresponds to the desired delivery rate in the stroke phase. At the end of each funding stroke an end position signal x or xx is tapped via an electrical or hydraulic scanning device in the area of the drive cylinder 5 and is applied to the electromagnetic or hydraulic pilot control input of the directional control valve 61 or 60 via an electrical or hydraulic signal converter 63 or 62. As a result, the control pressure p s = p₂ is now set by the throttle chain between the pre-throttle 69 and the variable throttle 65 (control specification p₂). During the changeover phase of the pipe switch, a new control pressure p s, which is higher or lower depending on the requirements, is set for controlling the delivery rate regulator 18. While the leading edge of the end position signal x or xx tapped at the drive cylinder 5 leads to the reversal of the directional control valve 61 or 60 almost without a time delay (in the hydraulic case according to FIG. 3 this is ensured by the check valve 64), occurs at the end of the switchover phase and thus at the beginning of the new delivery stroke, a delay in the changeover of the directional control valve 61 or 60 occurs via the delay element 63 or 62 (in the case of FIG. 3 caused by the adjusting throttle 66). This ensures that after reversing the diverter 3 and the subsequent reversal of the conveying direction in the delivery cylinders 5,5 ', the reversing pump 6 in the main circuit initially acts on the thick matter column to be pushed with the previously set delivery rate, which is the case, for example, with a previously set higher level Delivery rate for a brief acceleration of the thick matter column and for a pre-compression of the one inside Leads. On the side of the adjusting throttle 65 of the throttle chain, a high-pressure limiting valve 82 is also arranged, which enables the maximum high pressure to be adjusted during the changeover phase with a time delay. In the event of high pressure, the limiting valve 82 lowers the control pressure between the throttle 69 and the adjusting throttle 65, so that the main pump 6 can be pivoted back to a correspondingly lower delivery rate, in particular to the delivery rate 0. In another line of the throttle chain there is an externally controllable changeover valve 68, which is blocked in the spring-centered position and forms a direct drain to the tank in the switched-on position behind the throttle 69, so that the hydraulic pump 6 is set up via the control pressure p s = 0 Flow rate 0 can be switched.

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 und des Wegeventils 61 (bzw. 60) 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. Da das Wegeventil 61 (bzw. 60) über das Verzögerungsglied 63 (bzw. 62) zeitverzögert umgeschaltet wird, wird die Fördermenge der Hydropumpe 6 zunächst durch die Drosselkette 69,65 bestimmt (Regelvorgabe p₂) und erst nach Ablauf der Verzögerungszeit auf den durch die Drosselkette 69, 125 definierten Wert (Regelvorgabe p₁) umgeschaltet. Das Umsteuersignal wird parallel dazu zwischen dem Ventil 20 und dem Stellzylinder 18 abgegriffen und 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. 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 Materialaufgabebehälter 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 valve 31 and the directional valve 61 (or 60) is triggered via the electrically tapped end position signal x. As a result, the reversing valve 30 is reversed by triggering a reversing process on the tubular switch cylinders 21, 21 ', the conveying direction of the reversing pump 6 initially being retained and the drive pistons 8, 8 'are held in their respective end positions via the pressure oil in line 11. 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. Since the directional control valve 61 (or 60) is switched with a time delay via the delay element 63 (or 62), the delivery rate of the hydraulic pump 6 is first determined by the throttle chain 69, 65 (control specification p₂) and only after the delay time has elapsed to Choke chain 69, 125 defined value (control specification p 1) switched. 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. 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. 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 material feed container.

Bei dem Ausführungsbeispiel nach Fig. 1 ist in der federzentrierten Stellung des Wegeventils 61 allein das Hochdruckbegrenzungsventil 70 wirksam, während in der durchgeschalteten Stellung des Ventils 61 das Hochdruckbegrenzungsventil 82 hierzu parallel geschaltet wird. Am Druckbegrenzungsventil 82 kann daher sinnvollerweise nur ein niedrigerer Druckgrenzwert eingestellt werden als am Ventil 70, was gleichbedeutend damit ist, daß in der durchgesteuerten Stellung des Ventils 61 nur ein niedrigerer Begrenzungsdruck als in der federzentrierten Stellung dieses Ventils eingestellt werden kann.In the embodiment of FIG. 1, the high-pressure limiting valve 70 is effective in the spring-centered position of the directional control valve 61, while in the switched position of the valve 61, the high pressure relief valve 82 is connected in parallel. Therefore, only a lower pressure limit value can be set at the pressure limiting valve 82 than at the valve 70, which is equivalent to the fact that in the controlled position of the valve 61 only a lower limiting pressure can be set than in the spring-centered position of this valve.

Mit dem in Fig. 4 gezeigten Ausführungsbeispiel wird dieser Nachteil dadurch vermieden, daß das Ventil 70 in einen der auswahlseitigen Steuerstränge des Wechselventils 61 gelegt wird, so daß die Einstellung des Begrenzungsdrucks in beiden Schaltstellung unabhängig voneinander erfolgen kann. Weiter sind in den beiden Steuersträngen Regelventile 200 und 300 angeordnet, deren Steuereingänge über das Wechselventil 72 mit der Hochdruckseite der Hydropumpe 6 verbunden sind und die den am Eingang anstehenden Vorgabedruck p₁ bzw. p₂ nach Maßgabe einer hyberbolischen Abhängigkeit aus Hochdruck und Fördermenge (Vorgabewert p₁,p₂) einregulieren. Damit kann eine an die Anforderungen beim Fördervorgang und beim Umschaltvorgang angepaßte Drehmomentbegrenzung für den Antriebsmotor der Pumpe 6 eingestellt werden.With the embodiment shown in Fig. 4, this disadvantage is avoided in that the valve 70 is placed in one of the selection-side control lines of the shuttle valve 61, so that the setting of the limiting pressure in both switching positions can take place independently of one another. Furthermore, control valves 200 and 300 are arranged in the two control lines, the control inputs of which are connected via the shuttle valve 72 to the high-pressure side of the hydraulic pump 6 and which control the set pressure p 1 or p 2 at the input in accordance with a hyberbolic dependency of high pressure and flow rate (set value p 1, p₂) adjust. A torque limitation for the drive motor of the pump 6 can thus be adjusted to the requirements during the conveying process and during the switching process.

Claims (18)

  1. Control arrangement for a two-cylinder viscous material pump, comprising at least one hydro pump (6), the conveying volume of which is adjustable by means of a command signal (p₁, p₂), two conveying cylinders (1, 1'), which communicate with a material supply tank and which are operated in contraflow by means of drive cylinders (5, 5') driven by the hydro pump (6), with a directing mechanism (3) for the material flow, which alternately connects the conveying cylinders (1, 1') to the material supply tank and to a conveying pipe (4) and which is operated by a hydraulic diverting mechanism (21, 21') which is preferably arranged as a pipe branch for the flow of material, with a probe which responds to the end of each pressure stroke of the drive and/or conveying cylinders and at the outlet of which an end-position signal (x, xx) is triggered which initiates a redirecting process of the directing mechanism, and with a switch element (60̸, 61), which is at the outlet connected to a conveying volume control (18) of the hydro pump (6) and which comprises a control input, which is loaded by end-position signals (x, xx) or with control signals which have been derived from the end-position signals by signal conversion, as well as at least two switch positions, which are set by means of the signal level at the control input, for passing on different command signals (p₁, p₂) to the conveying volume control (18), characterised in that the drive cylinders (1, 1') and the hydraulic redirecting mechanism (21, 21') of the control arrangement (3) are operated via a servo control alternately by hydraulic oil from the same hydro pump (6), and that, during the pressure stroke of the drive cylinders (5, 5') and the redirecting process of the hydraulic redirecting mechanism (21, 21'), the conveying volume control (18) of the hydro pump (6) is loaded with command signals (p₁, p₂) which are independent of each other and wherein the stroke reversal in the drive cylinders (5, 5') is triggered at the end of each redirecting process of the control arrangement.
  2. Control arrangement according to claim 1, characterised in that that the command signals (p₁, p₂) have an operational dependence of operating parameters of the two-cylinder viscous material pump, in particular of the hydro pump, which is selected according to the control position of the switch element (60̸, 61).
  3. Control arrangement according to claim 2, characterised in that the command signals (p₁, p₂) are adjusted in dependence of a maximum conveying pressure of the hydro pump (6) according to the switch position of the switch element (60̸, 61).
  4. Control arrangement according to claim 2 or 3, characterised in that the command signals (p₁, p₂) can be altered in dependence of a selected maximum value of the product of conveying volume and conveying pressure of the hydro pump (6) according to the switch position of the switch element (60̸, 61).
  5. Control arrangement according to one of claims 1 to 4, characterised in that in front of the control inlet of the switch element (60̸, 61) is arranged a signal converter (62, 63), which is at the input loaded with the end-position signal (x, xx) and the output signal of which has a rear flank with adjustable lag relative to the end-position signal.
  6. Control arrangement according to claim 5, characterised in that the output signal of the signal converter (62, 63) has a front flank which substantially coincides temporally with the end-position signal (x, xx).
  7. Control arrangement according to claim 5 or 6, characterised in that the signal converter (62, 63) has a time-delay element (66), preferably with adjustable delay time, which responds to the rear flank of the end-position signal (x, xx).
  8. Control arrangement according to one of claims 5 to 7, characterised in that the hydraulic signal converter (62) has an adjustable throttle (66) and a non-return valve (64), which is arranged parallel to the throttle and which opens from the probing mechanism (x, xx) towards the control input.
  9. Control arrangement according to claim 7, characterised in that the time-delay element has a digital counter or and electronic circuit in the form of an RC unit.
  10. Control arrangement according to one of claims 1 to 9, characterised in that the switch element is arranged as a directional valve (60̸, 61) comprising an electrically, hydraulically or pneumatically operated pre-control valve as input control, at least two selector connections which are adjustable to at least two different command signals (p₁, p₂), and an operational connection (ps), which is connected to the conveying volume control (18) of the hydro pump (6) and selectively connectable to one of the selector connections.
  11. Control arrangement according to claim 10̸, characterised in that at least one of the selector connections is loaded by a variable adjustable command value (p₁, p₂).
  12. Control arrangement according to claim 10̸ or 11, characterised in that the directional valve can be redirected between at least two control lines, which are arranged at the side of the selector connections and fitted with throttles (65, 125), pressure-maintaining valves and/or pressure-limiting valves (70̸, 82).
  13. Control arrangement according to one of claims 10̸ to 12, characterised in that the directional valve (60̸, 61) can be redirected between at least two parallel lines of a throttle chain (69, 125 or 69, 65 respectively), which are arranged at the side of the selector connections.
  14. Control arrangement according to claim 13, characterised in that an adjustment throttle (125, 65) is arranged at least in one of the parallel lines of the throttle chain.
  15. Control arrangement according to one of claims 12 to 14, characterised in that the control lines and/or the throttle chains are preferably loaded via an auxiliary pump (25) with a specified control pressure (ND).
  16. Control arrangement according to one of claims 12 to 15, characterised in that in at least one of the control or throttle lines is arranged an adjustable pressure-restricting valve (70̸, 82), which is at one control input connected to the high-pressure side of the hydro pump (6) and which controls the command signal (p₁, p₂) in the form of a hydraulic pressure.
  17. Control arrangement according to one of claims 12 to 16, characterised in that in at least one of the control or throttle lines is arranged a control valve (20̸0̸, 30̸0̸), which is controlled by the high-pressure signal (HD) of the hydro pump (6) and by the command signal (p₁, p₂) which is preferably in the form of a hydraulic pressure, for the purpose of setting a command signal (p₁, p₂) in dependence of the product of high pressure (HD) and command value (p₁, p₂).
  18. Control arrangement according to one of claims 1 to 17, characterised in that the stroke reversal in the drive cylinders (5, 5') is initiated by a command mechanism (y) which is triggered at the end of each redirecting process of the control arrangement (3).
EP90903351A 1989-03-29 1990-01-18 Control arrangement for a two-cylinder pump for thick materials Expired - Lifetime EP0465474B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3910120A DE3910120A1 (en) 1989-03-29 1989-03-29 CONTROL ARRANGEMENT FOR A TWO-CYLINDER FUEL PUMP
DE3910120 1989-03-29

Publications (2)

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EP0465474A1 EP0465474A1 (en) 1992-01-15
EP0465474B1 true EP0465474B1 (en) 1993-09-01

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EP90903351A Expired - Lifetime EP0465474B1 (en) 1989-03-29 1990-01-18 Control arrangement for a two-cylinder pump for thick materials

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US (1) US5238371A (en)
EP (1) EP0465474B1 (en)
JP (1) JPH04504292A (en)
DE (2) DE3910120A1 (en)
ES (1) ES2045908T3 (en)
WO (1) WO1990011449A1 (en)

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Publication number Publication date
US5238371A (en) 1993-08-24
ES2045908T3 (en) 1994-01-16
DE3910120A1 (en) 1990-10-04
WO1990011449A1 (en) 1990-10-04
DE59002577D1 (en) 1993-10-07
JPH04504292A (en) 1992-07-30
EP0465474A1 (en) 1992-01-15

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