EP2949931A1 - Pulsator - Google Patents

Abstract

The present invention relates to a device for generating an oscillating movement of a fluid, in particular a pulsator device, with a fluid displacement element movable alternately in a suction direction and in a pressure direction, wherein the course of the movement speed of the fluid displacement element in the pressure direction and / or in the suction direction is adjustable ,

Description

The invention relates to a device for generating an oscillating movement of a fluid, in particular a pulsator device, with a fluid displacement element movable alternately in a suction direction and in a pressure direction, according to the preamble of patent claim 1.

Pulsators are used, for example, as a drive for extraction columns. Usually, the sequence of movements of the oscillating hydraulic movement by an inserted crank mechanism is almost sinusoidal. The amplitude and the frequency of the pulsation are usually adjustable. A second area of application for high-pressure pulsators is component testing. In this connection, by way of example, the publication WO 2008/083961 A1 directed.

By means of the pulsator, the space available to the fluid is alternately cyclically reduced and enlarged, so that the pressure under which the fluid stands alternately changes. This cyclic (or "oscillating") movement of the space increasing and decreasing fluid displacement element results in the generation of the oscillating fluid movement. A suction stroke (the fluid displacement element or a part thereof moves in the suction direction) and a pressure stroke (the fluid displacement element or a part thereof moves in the pressure direction opposite the pressure direction) alternate cyclically. It is important that in a pulsator, unlike, for example, in a pump, no fluid transport from a fluid inlet to a fluid outlet takes place, but that the fluid is moved oscillating, whereby a cyclically (eg. Wavy or sinusoidal) changing pressure in a The working space connected to the pulsator can be generated.

Furthermore, different methods for cleaning filters are known from the prior art. For example, it is known to use pressure pulses for filter cleaning. The publication DE 19608104 C1 describes a method for pressure pulse backwashing of filters. The disadvantage here is the high expenditure on equipment. The necessary for backwashing hydraulic accumulator has a limited capacity and must be returned to the initial state, that is filled.

Based on the described prior art, the invention has the object to provide a pulsator, which is more flexible, so that it can be used for other tasks such as filter cleaning.

This object is achieved by a device according to claim 1. Advantageous developments of the invention are described in the dependent claims. The inventive device for generating an oscillating hydraulic fluid movement is characterized in that the movement speed of the fluid displacement element or its course in the pressure direction and / or in the suction direction is adjustable as needed, preferably the course of the movement speed of the fluid displacement element in the printing direction independently of the course of the movement speed of the fluid displacement element in the suction direction is adjustable. In other words, the amount and / or the time course of the movement speed of the fluid displacement element in the printing direction can be set differently as desired in the suction direction. For example. the speed is adjustable so that the fluid displacement element in the printing direction in the middle and / or in sections moves faster than in the suction direction or vice versa.

The invention is based on the finding that filters can be cleaned only insufficiently by means of a conventional pulsator, in which the speed of movement of the fluid displacement element in the direction of pressure and in the suction direction with the opposite sign is the same, since soiling after a printing cycle again on the Can settle filters. On the other hand, a pulsator can be used particularly effectively for filter cleaning, and a good cleaning effect can be obtained when the fluid displacement element is moved in the positive direction at a fast speed and in the negative direction at a slow speed. Preferably, the speed is quickly established during the compression stroke and set up slowly during the suction stroke.

However, it must be ensured that the fast pulse movement is limited in such a way that no damage is caused to the filter itself. It is also advantageous if the temporal course of motion and / or the speed amount can be changed or adjusted as required, e.g. to take into account the different properties of filters and filter media. Movement pauses of the fluid displacement element can be inserted between the pressure pulses of the fluid displacement element, in which the filter or filters to be cleaned can operate normally.

The pulsator according to the invention can be designed differently. According to a first possible embodiment, the pulsator is equipped with a linear drive and according to a second possible embodiment, the pulsator is equipped with a spring cam drive or crank drive and / or with a rotating electric drive.

Possible examples are: an electric linear drive with a direct connection to the displacement element; a mechanical linear drive (eg ball screw) with a rotating electric drive; a driven by a rotating electric drive spring cam drive or crank drive with reduction gear to reduce the stroke frequency; a driven by a rotating electric drive spring cam drive or crank drive with stroke adjustment to reduce the stroke length. Pulsators with higher power are preferably carried out with spring-cam drive or crank drive and reduction gear.

The pulsator according to the invention can be constructed as a piston, diaphragm or Faltenbalgpulsator. Bellows pulsators are e.g. in the publication D8-940d, Issue 8/1978, LEWA Herbert Ott GmbH + Co described.

In a particularly preferred embodiment of the invention, the fluid displacement element in the form of a mechanically or hydraulically driven diaphragm or Faltenbalgelements and / or a mechanically actuated piston is formed. The durability of the membrane element and the ability to monitor proper filter cleaning can be improved by designing the membrane element as a sandwich membrane with membrane rupture indicating means. A central membrane region can be accommodated between two holding elements, such as holding plates or support plates, which stabilize and strengthen the central membrane region driven by the drive. In the case of a membrane as a fluid displacement element, the movement speed of the central membrane region coupled to the drive element is understood as its movement speed.

Particularly important according to the invention is a drive for driving the fluid displacement element, which has a highly dynamic electric drive, preferably a servo motor, in particular a permanently excited three-phase synchronous servo motor. By means of a servomotor, which is preferably equipped with an integrated position feedback, the exact course of movement of the fluid displacement element can be predetermined and controlled. In particular, the rotational speed on the servomotor can be set in such a way that a certain course of motion of the fluid displacement element results, wherein the course of motion in the pressure direction and in the suction direction can differ.

Preferably, a coupled to the fluid displacement element and driven by an eccentric shaft push rod is provided, wherein the eccentric shaft of the drive is driven. Such a drive train is namely particularly reliable and durable.

With regard to a reliable position determination of the fluid displacement element, it has proved expedient to provide a sensor connected to a control device of the drive, such as an electrical sensor for detecting a predetermined position of the fluid displacement element or a connected movable drive part such as a push rod, wherein the sensor can be provided for the transmission of a determined position information to the control device. In a reference run, the rear dead center of the fluid displacement element can be detected by means of the sensor and stored in the control for driving the drive.

As an alternative to the automatic reference travel with the aid of the sensor, manual adjustment of the fluid displacement element in the rear dead center and storage of this position are also possible.

The sensor may be adapted to detect a dead center or reverse position of the fluid displacement element, and in this case is preferably located at a stationary mounting point in the housing of the pulsator opposite a rear end of the pushrod driving the fluid displacement element at the rear reversal point.

With regard to a simple and expedient embodiment of the device according to the invention, it has proved to be advantageous to provide a pulsator space for the fluid with a fluid flow path extending from a fluid opening to the fluid displacement element, which is flowed through in one direction during the movement of the fluid displacement element in the pressure direction and in the movement of the fluid displacement member in the suction direction in the reverse direction. The fluid opening is not necessarily located on a movement axis of the fluid displacement element or of this driving push rod. In other words, the fluid flow path may be shaped in response to the desired flow and pressure pulsing behavior of the fluid.

With regard to an effective filter cleaning, it has been found to be particularly advantageous that the movement speed of the displacement element is adjustable so that the displacement element in the printing direction on average more than twice as fast, preferably more than three times as fast, especially five times as fast or moved faster than in the suction direction, or vice versa. In this case, filter contaminants are reliably removed and moved away from the filter to be cleaned in the case of several consecutive movement or lifting cycles of the fluid displacement element. Particularly useful are a high (average) velocity of the fluid displacement element during the compression stroke and a low (average) velocity of the fluid displacement element during the suction stroke. Depending on the installation of the filters to be cleaned in the fluid movement path, a reversed course of movement of the fluid displacement element may also be expedient.

Alternatively or additionally, the movement speed of the displacement element can be adjusted such that the displacement element preferably moves abruptly in sections in the pressure direction and / or in the suction direction. A jerky movement is understood as meaning a particularly fast movement in a narrowly restricted time window, the movement speed being significantly slower both before and after the time window than during the time window. For example. the speed amount during the kick is more than 5 times as large as following the kick or before. A shock-shaped movement of the displacement element, in particular at the beginning of the pressure stroke, serves to dissolve stubborn dirt from the filter to be cleaned.

Particularly preferred is a course of movement of the displacement element, wherein the displacement element abruptly moves at the beginning of the pressure stroke, wherein the movement speed decreases gradually following the pressure surge to the dead center of the displacement element or at the beginning of the subsequent suction stroke. In the suction direction, the fluid displacement element preferably moves (at least in the middle) much slower, and more preferably at least in sections, with substantially constant Speed. Preferably, the suction stroke lasts more than twice as long, in particular 5 times as long or more than the pressure stroke.

Alternatively or additionally, the movement speed of the displacement element is adjustable such that the displacement element is stationary at least at one reversal point or at a dead center, at least temporarily. This results in at least one of the dead points a movement pause of the fluid displacement element. Preferably, a break in movement takes place at both dead centers, wherein the break at the transition from the suction stroke to the pressure stroke is preferably longer, preferably more than twice as long, in particular 10 times as long or longer than the break at the transition from the pressure stroke to the suction stroke. If necessary, a normal filter operation can take place between the individual stroke cycles or between groups of several stroke cycles.

Alternatively, it is possible to provide an (additional) standstill of the fluid displacement element during the pressure strokes and / or during the suction stroke. For example. For example, a single pressure stroke may consist of two or more pressure surges each interrupted by a break in movement.

The invention further relates to a method for operating a device according to the invention, in particular for operating a pulsator according to the invention, wherein the fluid displacement element is moved during the pressure stroke with a different (average) speed amount and / or a different speed profile than during the suction stroke. In particular, the fluid displacement element is preferably moved or driven by means of a servomotor in such a way that the above-described courses of motion result. Reference is made to the above statements.

Fig. 1

einen Pulsator mit mechanisch angetriebener Membran, und in

Fig. 2 a-e

verschiedene Diagramme mit unterschiedlichen Verläufen des Wegs s des Verdrängungselements, aufgetragen über der Zeit t.

The invention is explained in more detail below in the form of an embodiment with reference to the drawing. This shows in:

Fig. 1

a pulsator with mechanically driven membrane, and in

Fig. 2 ae

different diagrams with different gradients of the displacement s of the displacement element, plotted against the time t.

Like from the Fig. 1 it can be seen, the illustrated pulsator 100 has a fluid displacement element 2 in the form of a mechanically hinged membrane. This is peripherally clamped between a Pulsatorkörper 3 and a Pulsatordeckel 4 and firmly connected centrally with a support plate 5 serving for membrane drive. Here, the central membrane clamping is carried out such that the membrane 2 is arranged in its central region between the support plate 5 and a holding plate 6, which is screwed into a threaded bore of the support plate 5. The support plate 5 in turn is attached to the end of a reciprocally displaceable push rod 7, which is guided and supported sealed in the Pulsatorkörper 3. Here, the in Fig.1 from right to left taking place drive movement of the push rod 7 - and thus the pressure stroke of the diaphragm 2, during which the center of the diaphragm 2 in the pressure direction D moves mechanically by means of a drive motor 8 via a worm gear 9 and an eccentric shaft 13 causes. In contrast, the in Fig. 1 From the left to the right resuming movement of the push rod 7 - and thus the suction stroke of the membrane 2, during which the membrane 2 in the suction direction S is achieved via a compression spring 10 which extends between an inner housing fixed shoulder 11 of the Pulsatorkörpers 3 and a shoulder 12 of the Push rod 7 is supported.

The pulsator cover 4 forming the pulsator head defines, together with the membrane 2, a pulsator space 15 into which the fluid to be moved can enter and exit via a fluid opening 14 with a threaded connection.

The fluid flow path extends from the diaphragm 2 through the pulsator space 15 to the fluid port 14, and a filter cleaning space (not shown) with filters disposed therein and to be cleaned may be in fluid communication with the fluid port 14. Preferably, the filter surface to be cleaned is perpendicular to the oscillating fluid flow to be generated by the pulsator.

Details with regard to the membrane attachment are in the document EP 0418 644 B1 described their contents by reference in the present Revelation is included. The membrane 2 can, as in the EP 0418 644 B1 described be designed as a sandwich membrane with a device for membrane rupture display.

The drive motor 8 is designed as a highly dynamic drive with an associated controller 16. This is preferably a servomotor, in particular a permanent-magnet three-phase synchronous servo motor. Motor and control are connected via a supply and control line.

An electrical sensor 13 is connected to the controller 16 and is provided for detecting the rearward position of the push rod 7. In a reference run the rear dead center is detected by means of the encoder and stored in the controller 16 of the drive. After the reference point has been stored in the controller 16, the position of the diaphragm can be calculated at any time with the selected worm gear ratio, the kinematics of the eccentric and the feedback data of the drive.

The drive motor 8 can be operated via the controller 16 such that any predetermined pulsation movements can be generated. In particular, both the speed amount and the speed profile of the membrane 2 can be set differently during the pressure stroke and during the suction stroke, so that the pulsator according to the invention can also be used for filter cleaning with optimum cleaning results.

This procedure, which is operated with the device according to the invention, is illustrated by the individual diagrams of FIG FIGS. 2a to 2e represented in the form of path-time curves of the fluid displacement element 2. The diagrams in the FIGS. 2a to 2c each show a complete stroke cycle (pressure stroke and subsequent suction stroke of the displacement element 2) and a part of the adjoining second stroke cycle.

Alternatively, a break can be installed between the individual lifting cycles, in which the displacement element does not move and over a short or long time at the rear dead center (transition between suction stroke and the next pressure stroke) dwells. These breaks are in the diagrams of Figures 2d and 2e especially long and therefore abbreviated.

Fig. 2a:

The average velocity of the displacement element is much higher in the pressure stroke than in the suction stroke (here: more than 5 times higher). The pressure stroke is performed at a substantially constant, very high rotational speed on the drive motor. The suction stroke is also performed at a substantially constant, but very low rotational speed on the drive motor.
The time profile of the speed of the displacement element results in particular from the kinematics of the eccentric and is shaped sinusoidally for both directions of movement (pressure stroke, suction stroke). In particular, no sudden speed changes of the displacer occur.

Fig. 2b:

In contrast to Fig. 2a the rotational speed on the drive motor is changed over the rotation angle such that the speed of the displacement element in the respective phase (pressure stroke, suction stroke) is approximately constant. At the two reversal points, the speed of the displacer changes abruptly. The approximately constant speed of the displacer during the pressure stroke is almost 8 times as high as the constant speed in the reverse direction during the suction stroke.

Fig. 2c:

In contrast to Fig. 2b starts the pressure stroke jerky with very high speed of the displacer and is reduced towards the front dead center. The velocity course during the suction stroke is essentially the same Fig. 2b ,

Fig. 2d:

The course of movement essentially corresponds to that in Fig. 2b , but with additional breaks at the two turning points. The speed of the displacer during the suction stroke and during the pressure stroke is in each case Essentially constant. The break in the rear dead center (transition between intake stroke and compression stroke) is significantly longer than the break in the front dead center (transition between compression stroke and suction stroke). This interval sets the time interval between individual pulses.

Fig. 2e:

The course of movement essentially corresponds to that in Fig. 2d , but with a pause interrupted by a pause. The pressure stroke is divided into two parts and provided with another break.

LIST OF REFERENCE NUMBERS

2

Fluid displacement element / membrane

3

Pulsatorkörper

4

Pulsatordeckel

5

backing pad

6

Retaining plate

7

pushrod

8th

drive motor

9

worm gear

10

compression spring

11

first shoulder

12

second shoulder

13

eccentric shaft

14

The flow-through opening

15

pulsator

100

pulsator

Claims (11)

Device (100) for generating an oscillating movement of a fluid, in particular pulsator device, with a fluid displacement element (2) movable alternately in a suction direction (S) and in a pressure direction (D),
characterized,
that the course of the movement speed of the fluid displacement member (2) in the printing direction (D) and / or in the suction direction (S) is adjustable. Apparatus according to claim 1, characterized in that the course of the movement speed of the fluid displacement element (2) in the pressure direction (D) is independent of the course of the movement speed of the fluid displacement element in the suction direction (S) adjustable. Apparatus according to claim 1 or 2, characterized in that the fluid displacement element (2) has a mechanically or hydraulically driven diaphragm or Faltenbalgelement and / or a mechanically actuated piston. Device according to one of the preceding claims, characterized by a drive (8) for driving the fluid displacement element (2) having a highly dynamic electric drive, preferably a servomotor, in particular a permanent-magnet three-phase synchronous servo motor, the drive (8) preferably with an integrated Position feedback is equipped. Device according to one of the preceding claims, characterized by a with a control device (16) of the drive (8) connected Sensor (13) such as an electric encoder for detecting a predetermined position of the fluid displacement element (2) or an associated movable drive part (7) and for forwarding a determined position information to the control device (16). Apparatus according to claim 5, characterized in that the sensor (13) for detecting a dead center or reversal point position of the fluid displacement element (2) or an associated drive part (7) is arranged. Device according to one of the preceding claims, characterized by a Pulsatorraum (15) with a starting from a fluid opening (14) in the direction of the fluid displacement element (2) extending fluid flow path which during the movement of the fluid displacement element (2) in the printing direction (D) in the one direction is flowed through and in the movement of the fluid displacement element (2) in the suction direction (S) is flowed through in the reverse direction. Device according to one of the preceding claims, characterized in that the course of the movement speed of the fluid displacement element (2) is adjustable such that the fluid displacement element in the printing direction (D) on average more than twice as fast, preferably more than three times as fast, in particular moved five times faster or faster than in the suction direction (S), or vice versa. Device according to one of the preceding claims, characterized in that the course of the movement speed of the fluid displacement element (2) is adjustable such that the fluid displacement element (2) in the pressure direction (D) and / or in the suction direction (S) at least partially jerky moves , Apparatus according to claim 9, characterized in that the course of the movement speed of the fluid displacement element (2) is adjustable so that the fluid displacement element (2) in the printing direction (D) moves abruptly at the beginning and then with gradually decreasing velocity and / or that the fluid displacement element (2) in the suction direction (S) moves slowly and preferably at least in sections at a substantially constant speed. Device according to one of the preceding claims, characterized in that the course of the movement speed of the fluid displacement element (2) is adjustable such that the fluid displacement element (2) at least at one reversal point (U) is at least temporarily stationary.

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