DE3105649A1 - Dosing pump - Google Patents

Description

Patent attorneys Dipl.-Ing. Han & Langosch *: Or: -lngi! Hef6z Hosenthien 7000 Stuttgart 1 Herdweg te Tel * efeh «(Ö7.11) 29-05 2 #.

3JJD5649

Applicant;

Hartmann. & Lämmle GmbH + Co.KG

Schuckertstrasse 15th

Rute3heim

Dosing pump

The invention relates to a metering pump with at least one pump piston guided in a pump housing, ' its stroke frequency and / or its effective piston stroke adjustable and the pump piston for this purpose o a speed and / or stroke adjustable drive boweqbai is.

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Dosing pump drives with mechanically controlled pump piston movements are known, which have to be adjusted in the crank drive technology depending on the dosing volume, i.e. the crank radius or the length of the push rod driven by the crank radius is changed. This will the metering stroke of the pump piston i η changed its path according to the desired volume requirement. Since it is necessary to intervene in the performance range of the ram transmission with these adjustments here highly rigid actuators are interposed, which, when the stroke is changed, the adjustment of the volu- ' have to make a metric stroke change.

Furthermore, hydraulically controlled metering pump drives are known. This is done by a black and white control a working cylinder for driving the pump piston between two externally adjustable fixed stops moved back and forth. The braking and acceleration curves are driven by end position cushioning. There is no change in the curve for acceleration and braking after such a drive has been manufactured more possible, since this end position damping can only be achieved through manufacturing-related attachment options will. Incidentally, the attacks must also be against

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the working pressure that the working cylinder generates, adjusted. Remote adjustments, controlled from process-controlled systems, should be attached here larger efforts are necessary here as well.

Both systems mentioned have the disadvantage that changes to the acceleration and deceleration curves can only be done with great mechanical effort. Since such pump drives, however Often having to convey a wide variety of media via metering pumps are ideal suction or discharge curves not predictable.

The object of the present invention is to avoid of the disadvantages described to create a metering pump of the type mentioned, which with can be adapted to different conveying media and conveying conditions with little effort, in particular without complex mechanical precautions.

To solve this problem, the invention provides that as a drive for the piston or pistons at least a hydraulically or pneumatically actuated working cylinder is provided that this or diono

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Working cylinder via an electronic control in their stroke and their stroke speed, are controllable and that for this purpose the piston speed and the piston travel is specified via an electronically controlled stepper motor and via a follow-up control adjustable with an actual value feedback '.

In this way, especially in process-controlled systems, e.g. in the chemical processing industry the dosage can be adapted automatically to the required process cycle within wide limits, including itself it is easy to change the substances to be conveyed without mechanical changes to the dosing pump.

The piston rod of the working cylinder with the pump piston can be designed in a particularly simple manner in a known manner Way be coupled and it can further the coupling rod or a piston rod extension part of the Be actual value feedback. In particular, a part of the piston rod or the piston rod extension can be a Wear toothing in which a pinion of the actual value feedback meshes. This is the pressurization of the working cylinder depending on the deviation of the actual position of the connecting rod or the piston rod extension from the specified target position over

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controlled by a hydraulic control valve.

With relatively little design effort, the maximum delivery rate can be doubled be achieved that symmetrically two pumps and working cylinder are provided, which have only one Follow-up control are controllable. Both working cylinders are in the synchronous mechanical control circuit switched on, with each of the two metering pumps performing their full capacity at the same time can and it can with the coupling of each cylinder for itself in the effect of the suction and impact movement can be driven at full power.

In a preferred embodiment, the Piston rod extensions of the two working cylinders each carry a toothing that is advantageous over

the pinion of the actual value feedback is mutually coupled #% are. The two pumps and working cylinders be arranged point-symmetrically to the pinion of the actual value feedback, so that the two pumps always run in the same direction and the suction and pushing movements can be optimally controlled.

In another embodiment, the pistons of the two working cylinders are aligned over a common one

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Carbon rod extension connected to one another. With this tandem solution, one pump is always alternately in suction mode and the other in delivery mode drove. Due to the superimposition of suction and conveying operation, however, there is optimum control here limited at the performance limits.

A materially reduced construction effort can be achieved in that the housing for the Actual value feedback at the same time as a cover

K) of the working cylinder is used in which the corresponding Channels for the pressure medium supply and discharge from and to the control valve are arranged directly, so that at least a part of the necessary connection ■ Mts and screw connections can be saved can. A further simplification can be achieved in that the jacket tube of the working cylinder is screwed directly into the housing of the actual value guide.

Further designs according to the invention are the subclaims and their advantages are explained in more detail in the description below. In the attached drawings shows:

Fig. 1 is a schematic representation

a dosing pump with two

.Pumps and working cylinders

in tandem,

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2 shows a longitudinal section through the two working cylinders arranged in tandem,

3 shows a piston speed-stroke diagram, that in Figs

illustrated embodiment of a Dosing pump,

Fig. 4 shows another embodiment two pumps and working cylinders and

5 shows a longitudinal section through the two arranged point-symmetrically Working cylinder of the metering pump version shown schematically in FIG.

In the exemplary embodiments described below, the same reference numbers are used for the corresponding parts used. When in Fig. 1 schema ti r.ch darcjosle I 1 t on Embodiment of a metering pump are two pumps 1, 1 'and two working cylinders 2, 2' in their axial

Extension coupled to one another in alignment via a coupling rod. Next are the pistons 4,4 'of the pumps 1,1' connected directly to the piston rods 5, 5 'of the associated working cylinder 2 and 2'. The coupling rod 3 is provided mit.einer toothing 6, which in one

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* At

R.it./.ol 7 combs an actual value feedback 8. the Actual value feedback 8 is part of a follow-up control 9. The setpoint of the follow-up control 9 is specified by an electronic controller 10 via a stepper motor 11 according to the Dosing needs. The stepping motor 11 controlled by the electronic controller 10 is via a toothed belt 12 coupled to a setpoint input 13 of the follow-up control 9.

The follow-up control 9 is connected to a pressure oil supply 14, an oil return 15 and connecting lines A and B, A ¹ , B 'with the pressure chambers 16, 16', 17, 17 'of the two working cylinders 2, 2' via a control valve not shown in detail. In the event of a corresponding deviation of the actual value from the specified setpoint, a displacement of the pistons 18, 18 'is achieved in a known manner via the follow-up control 9 by means of pressure oil admission or pressure oil return, whereby the piston 4,4' of the pumps 1,1 'is achieved via the piston movement. moves and the print medium is conveyed or sucked in in the direction of arrows 19, 19 '.

In Fig. 2 is a constructive embodiment. a metering pump construction according to FIG. 1 without Pumps shown. The coupling rod 3 is in this

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/ 13

Construction guided displaceably in a housing 20 of the follow-up control 9 and via an eccentric roller 21 held in engagement with the pinion 7 without play. The coupling rod 3 itself is guided to the inner end of the two hollow piston rods 5.5 'and firmly hinged there, and so it penetrates the pistons 18,18 'of the two working cylinders. 2.2 '.

The interior of the piston rods 5.5 'is each over an inner tube 22,22 'from the working spaces 16,17,16', 17 ' sealed with the arrangement of appropriate seals. Through this hollow design of the piston rods 5.5 ' a significant reduction in the overall length can be achieved.

To further shorten the overall length and to save on individual parts and screw connections, the jacket pipes 23, 23 'of the working cylinder 2, 2' are screwed tightly directly into the housing 20, the lines A ¹ and B from the control valve (not shown). Follow-up control 9 are guided directly into the pressure chambers 17 'and 16, respectively.

In Fig. 3 is a piston speed-stroke diagram for one duty cycle is shown. That goes

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Acceleration curve 24 into a constant speed part 25 above and there is a deceleration in the end of the stroke, for example according to the deceleration curve 26. In the subsequent return stroke, the Movement corresponding to the acceleration curve 24 ', the constant speed part 25' over the deceleration curve 26 * back to the starting position. Thanks to the electronic control, this Curve according to the maximum power IC) Capability of the pressure oil supply 14 and the follow-up control 9 can be varied according to the needs and requirements for an optimal dosage.

In the embodiment of FIGS. 4 and 5, the two working pistons 2, 2 'with their respective coupling rods 3.3 'symmetrically to the pinion 7 of the actual value feedback 8 of the follow-up control 9 arranged. This point-symmetrical arrangement is special short design possible with the simultaneous advantage that both pistons 4,4 'either in the same direction promote or suck in, so that an optimal adaptation to the conveying conditions via the electronic control 10 and conveying materials is possible. For example, the acceleration curve must be 24.24 "for tough Conveyed media run flatter than with thinner ones.

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The rest of the structural design largely corresponds to the construction according to FIG. 2. The ends of the coupling rods 3, 3 ¹ protruding from the dome housing 20 are protected against dirt and damage by connecting pieces 27 and 27 ', which are screwed to the housing 2O.

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Claims (1)

/ 1 .1 Dosing pump with at least one pump piston (4,4 ') guided in a pump housing, whose stroke frequency and / or its effective piston stroke can be adjusted and the pump piston (4,4') can be moved for this purpose via a speed- and / or stroke-adjustable drive , characterized in that at least one hydraulically or pneumatically actuated working cylinder (2.2 ') is provided as the drive for the piston or pistons (4, 4') that this or these working cylinders (2, 2 ') have an electronic Control (10) in their hub and.ihrer Hubgeschwindig-. speed can be controlled and that for this purpose the piston speed and the piston travel are specified via an electronically controlled stepper motor (11) and can be adjusted via a follow-up control (9) with an actual value feedback (8). _ ^ 2. Dosing pump according to claim 1, characterized in that that the piston rod (5.5 *) of the working cylinder (2.2 ') is coupled to the pump piston (4,4 ') and that this coupling rod (3,3') or a Kolbnntnngcnverlängerung Is part of the actual value feedback (8). HSL-1706 073 ♦ » 3. Dosing pump according to claim 2, characterized in that part of the coupling rod (3,3 ') or the The piston rod extension has a toothing (6.6 *) that is in a pinion (7) for the actual value feedback (8) combs. 4. Dosing pump according to claim 2 or 3, characterized in that two pumps (1,1 ') and symmetrical Working cylinders (2, 2 ') are provided which can be controlled via only one follow-up control (9). 5. Dosing pump according to claim 4, characterized in that two symmetrical pumps (1,1 ') and working cylinder (2, 2 ') are provided and that the piston' Rod extensions or coupling rods (3.3 ") of the two working cylinders (2.2 ') each have a toothing (6,6 ') and that both toothings (6,6') of the piston rods or coupling rods (3,3 ') over the pinion (7) of the actual value feedback (8) are coupled to one another (Fig. 5). 6. Dosing pump according to claim 5, characterized in that the two pumps (1,1 ') and working cylinder (2,2') are arranged point-symmetrically to the pinion (7) of the actual value feedback (8). H&L 1706 073 7. Dosing pump according to claim 5 or 6, characterized in that that the piston rod extensions or coupling rods (3, 3 ') in the housing (20) of the actual value feedback (8) are slidably guided. 8. Dosing pump according to claim 5, characterized in that the piston (18,18 ') of the two working cylinders (2.2 ') in alignment via a common piston rod . Extension (coupling rod 3) are connected to each other in a housing (20) of the actual value guide (8) is slidably guided. 9. Dosing pump according to claim 7 or 8, characterized in that the housing (20) also serves as a cover for the working cylinder (2.2 ·) with corresponding channels A, A ¹ , B, B ¹ for the pressure oil supply and discharge. 10. Dosing pump according to claim 3, characterized in that the toothing (6,6 ') of the piston rod (5,5') or coupling rod (3, 3 ') meshes free of play in the associated pinion (7) via a pressure piece. 11. Dosing pump according to claim 10, characterized in that an eccentric adjustment (21,2I ¹ ) is used as a pressure piece. H&L 1706 073 12. Dosing pump according to claim 8 or 9, characterized in that the jacket tube (23,23 ') of the working cylinder (2,2') in the housing (20) of the actual value feedback (8) is screwed in tightly. 13. Dosing pump according to one of claims 1 to 12, characterized in that the piston rod (5.5 ') of the working cylinder (2,2 ') is hollow and the coupling rod (3,3') is inside at the hollow end coupled to the piston rod (5.5 ') and through the piston (18 or 18') of the working cylinder (2.2 ') is guided to the outside, the hollow interior of the piston rod (5.5 ') through an inner tube (22.22') is sealed against the pressure spaces (16, 17, 16 ', 1V) of the working cylinder (2.2'). H&L 1706 073