Oscillating displacement pump having an electrodynamic drive and method for operation thereof

Abstract

An oscillating positive displacement pump with at least one mobile part arranged to be movable relative to a fixed part. The mobile part is driven and drives a displacement element of the positive displacement pump. An electrodynamic drive is provided as a drive, on which a plurality of coils and permanent magnets are provided that are arranged on the mobile part of the drive respectively, and at least one guide member is provided on the drive, which allows the mobile part to move only along a degree of translation freedom. The positive displacement pump is designed as a diaphragm pump, which is associated with a measurement and control unit with a data storage and data processor, which processes a position signal of the mobile part and the strength of the drive current as a measured and/or control variable. An arrangement of a plurality of such positive displacement pumps and a method of operating at least one such oscillating positive displacement pump are also provided.

Claims

1. An oscillating positive displacement pump (1), comprising at least one mobile part (20), which is arranged to be moveable relative to a fixed part (30) a drive (10) that drives the at least one mobile part to drive a displacement element (40) of the positive displacement pump (1), the drive (10) has a plurality of energized coils (41) and permanent magnets (42), and the plurality of coils (41) or the plurality of permanent magnets (42) are arranged on the mobile part (20) of the drive (10) respectively, magnetic fields with an alternating direction are adapted to flow through the plurality of coils (41) upon energization, the plurality of coils having alternating winding directions, said magnetic fields being generated by the plurality of permanent magnets (42) due to an alternating polarization and being conducted into the coils (41) via magnetic poles (24), each one of said plurality of coils (41) upon energization is adapted to contribute a summable contribution to a force arising by this in an axial direction of the drive (10), at least one guide member (50a, 50b) is provided on the drive (10), which permits the mobile part (20) to move along only one degree of translation freedom, a measurement and control unit (45) with a data storage and data processor which is adapted to receive and process a position signal of the mobile part (20) and a strength of a drive current as at least one of a measured or control variable, wherein the positive displacement pump (1) is a diaphragm pump and the displacement element (40) is a diaphragm and the drive (10) is an electrodynamic drive free of pole pieces on the coils.

2. The pump as claimed in claim 1, wherein the pump (1) is a diaphragm fluid pump.

3. The pump as claimed in claim 1, wherein the at least one guide member (50a, 50b) is a sliding guide or a spring element (55).

4. The pump as claimed in claim 1, wherein the drive (10) comprises a linear body (11) and a mounting 12, which are arranged in a movable manner against each other, the linear body (11) is a rod (21), and the mounting (12) is a shell-shaped part (23), into an interior space (25) of which the rod (21) protrudes.

5. The pump as claimed in claim 4, wherein the linear body (11) is provided with the permanent magnets (42) with an alternating polarity and the shell-shaped part (23) is provided with the plurality of coils (41).

6. The pump as claimed in claim 4, wherein the linear body (11) forms the at least one mobile part (20) and the mounting (12) forms the fixed part (30).

7. The pump as claimed in claim 1, wherein the fixed part (30) is permanently connected to a housing (31) of the drive (10) or is connected as a single piece with the housing of the drive.

8. The pump as claimed in claim 1, wherein the mobile part (20) and the fixed part (30) are connectable to each other by the at least one guide member (50a, 50b).

9. The pump as claimed in claim 1, wherein the at least one guide member (50a, 50b) comprises at least two of the guide members (50a, 50b) that connect regions of the mobile and fixed part (20, 30) facing each other to each other.

10. The pump as claimed in claim 9, wherein one of the guide members (50a, 50b) is integrated into the displacement element (40) or forms the displacement element (40).

11. The pump as claimed in claim 1, wherein the at least one guide member (50a, 50b) is provided with a preload, which is applied to the displacement element (40) with a de-energized drive (10) in such a way that at least one of an inlet or an outlet opening of a working chamber (4) of the pump (1) is sealed.

12. The pump as claimed in claim 1, further comprising a spring (26) on the drive (10) that impinges the mobile part (20), such that the displacement element (40) with a de-energized drive seals at least one of an inlet or an outlet opening of a working chamber (4) of the pump (1).

13. The pump as claimed in claim 1, wherein the plurality of coils (41) and permanent magnets (42) are arranged in a row respectively.

14. The pump as claimed in claim 1, wherein the pump (1) comprises an essentially cylindrical or square pump head (5), one end region of which is provided with an inlet (6) and an outlet (8) for a fluid to be transported and continues into a housing (31) receiving the drive (10) in an essentially flush manner on the end region.

15. The pump as claimed in claim 1, further comprising a position sensor (46) incorporated in a region of the drive (10).

16. The pump as claimed in claim 15, wherein the position sensor (46) comprises a Hall sensor.

17. The pump as claimed in claim 1, wherein the measurement and control unit (45) is programmable such that the pump (1) with the drive (10) is configurable with work steps for aspiration and discharge of a medium to be transported.

18. An arrangement of a plurality of pumps (1), each as claimed in claim 1 to form a pump system with a number of working chambers (4) corresponding to a number of pumps (1), inlet and outlets of said working chambers being connected to each other in parallel respectively.

19. A method for operating a pump system with at least one positive displacement pump (1) as claimed in claim 1, comprising: associating the measurement and control unit (45) which includes the data storage and data processor with the at least one positive displacement pump (1), detecting and evaluating a development of an electrical current over time and a position of the drive (10) of the at least one pump (1) as a measured variable to determine a pressure in a working chamber (4) of the system associated with the at least one pump (1), and saving the determined pressure in the working chamber (4) with a calculable transmission behavior of the displacement element (40).

20. The method as claimed in claim 19, wherein the transmission behavior of a diaphragm serving as the displacement element (40) is described using the formula p=c.sub.1F+c.sub.2x, wherein p is the pressure in the working chamber, F is a connecting-rod force, x is a position of the drive and constants c.sub.1 and c.sub.2 are dependent on a geometry and material characteristics of the diaphragm.

21. The method as claimed in claim 20, wherein the transmission behavior of the displacement element (40) is described using the formula p=f (F,x) and thereby, the pressure in the working chamber (4) is described as a function of the connecting-rod force and the position of the drive (10) in a numeric manner.

22. The method as claimed in claim 19, wherein the pump system with the measurement and control unit (45) forms a control circuit, which is operated with the drive current strength and the position of the mobile part as a measured variable and with the pressure of the working chamber (4) as a control variable.

23. The method as claimed in claim 19, wherein the pressure is determined individually in both transfer directions of the pump (1) during aspiration and discharge of the medium to be transported.

24. The method as claimed in claim 19, wherein the pressure of a plurality of the pumps (1) associated with the pump system is determined, and the method further comprising separately regulating each of the pumps (1).

25. The method as claimed in claim 19, further comprising the measurement and control unit (45) compensating for developments of the pressure deviating from saved transmission profiles by manipulating the drive (10).

26. The method as claimed in claim 19, further comprising saving the transmission behavior of the diaphragm as a reference value table, determined by a finite element simulation for a number of positions and load cases and determining the transmission behavior to calculate the pressure from stored reference values and interpolations lying in between these values.

27. The method as claimed in claim 19, further comprising, determining a progression over time of the pressure for different speeds at an inlet and outlet (6, 8) of a medium to be transported from the working chamber (4) is determined by the measurement and control unit (45) and determining parameters of at least one of the medium or at least one transport device from said progression over time using an evaluation unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The pump according to the invention with an associated drive will be explained in more detail below based on the exemplary embodiments in the drawing. In a partly schematic illustration, the figures show:

(2) FIG. 1 a sectional lateral view of a first exemplary embodiment of a pump according to the invention with a fixed and a mobile part on its drive, wherein the coils are arranged on the fixed part;

(3) FIG. 2 a sectional lateral view of another exemplary embodiment of a pump according to the invention with a fixed and a mobile part on its drive, wherein the coils are arranged on the mobile part;

(4) FIG. 3 a flat top view of a guide member arranged between the mobile and fixed part from FIGS. 1 and 2.

DETAILED DESCRIPTION

(5) In FIGS. 1 and 2, a pump, which is indicated in its entirety with reference number 1 can respectively be seen. This pump 1 designed as a positive displacement pump comprises a pump head 5, by which an inlet 6 and an outlet 8 with the associated valves 7 and 9 are recognized. The pump 1 is provided with a mobile part 20, which is arranged in a movable manner relative to a fixed part 30 formed by a housing 31. The mobile part 20 in FIG. 1 is thereby a connecting rod 21, which is driven by the drive 10. Thereby, the driven mobile part 20 itself drives a displacement element 40 of the pump 1, wherein the drive 10 is formed by an electrodynamic drive. A plurality of coils 41 and permanent magnets 42 are provided on the drive 10, wherein the plurality of coils 41 (FIG. 2) or the plurality of permanent magnets 42 (FIG. 1) are respectively arranged on the mobile part 20 of the drive 10. Furthermore, two guide members 50a, 50b are respectively provided on the drives 10 in FIGS. 1 and 2, which allow the respective mobile part 20 to move along only one degree of translation freedom, which extends in the illustrations of FIGS. 1 and 2 along a vertical axis lying on the level of the viewer.

(6) Furthermore, it can be recognized that the drive 10 comprises a linear body 11 and a mounting 12, which are arranged in a movable manner against each other, wherein the linear body 11 is designed as a connecting rod 21 (FIG. 1) or as a rod 22 (FIG. 2) and the mounting 12 is designed as a shell-shaped part 23, into the interior space of which the connecting rod 21/rod 22 projects. Furthermore, it can be seen in FIGS. 1 and 2 that the linear body 11 is provided with the permanent magnets 42 with an alternating polarity and the shell-shaped part 23 is provided with the plurality of coils 41. Thereby, the permanent magnets 42 are arranged in a row over the primary part of the length of the linear body 11 in such a way that pronounced poles 43 result due to magnet ends of the same polarization lying opposite adjacent to one another. The poles 43 concerned are encompassed by annularly wound coils 41 with an alternating winding direction, which are arranged on the mounting 12.

(7) The magnetic return occurs either via the shell-shaped part 23 or the housing 31, which, in this case, are preferably made out of a ferromagnetic material.

(8) The fundamental difference between FIGS. 1 and 2 lies in the fact that, on the one hand, in FIG. 1, the linear body is formed by the connecting rod, which is the mobile part, and is encompassed by the shell-shaped part 23 as a fixed part, which therefore forms the mounting 12 while, on the other hand, in FIG. 2, the linear part via the rod 22 forms the fixed part 30 and the mounting 12 with the shell-shaped part 23 forms the mobile part 20. Accordingly, it behaves so that the linear body 11 forms the mobile part 20 and the mounting 12 forms the fixed part 30 or vice versa. Thereby, the fixed part 30 is fixedly connected to a housing 31 of the drive 10 or designed as a single piece with this; in the case of FIG. 1, the fixed part 30 is a part of the housing 31; in FIG. 2, it is fixedly connected to the housing as a rod 22. In both cases, the linear body 11 protrudes into the inside of the shell-shaped part 23, meaning in to the clear cross section 25 formed by the mounting 12.

(9) At its end regions, the linear body 11 is connected to the respective other part 30, 20 either as a mobile part 20 (FIG. 1) or as a fixed part 30 (FIG. 2) respectively via a guide member 50a, 50b; the guide member 50a is shown as a flat spring 49 in the FIG. 3 in detail. The displacement element 40 driven by the drive 10 via the coils 41 and the permanent magnets 42 is respectively connected to the mobile part 20 (linear body 11 in FIG. 1 and mounting 12 in FIG. 2); its movement carries out the strokes of the pump 1; at the same time, it limits the working chamber 4 of the pump 1 with the inner walls of the pump head 5. A spring 26 can be arranged between the mobile part 20 and the fixed part 30, which, as a compression spring, impinges the mobile part 20 in the direction of the pump head 5 so that, in the de-energized state of the coils 41, the working chamber 4 of the pump can be sealed by the displacement element 40.

(10) Both in FIG. 1 and FIG. 2, in any case, the mobile part 20 and the fixed part 30 can be connected or are connected to each other by at least one guide member 50a, 50b.

(11) In FIGS. 1 and 2, dashed contours can each be recognized, which show the progression of a related contour of a linear body 11, a mounting 12, a displacement element 40, an outer permanent magnet 42 and guide members 50a, 50b, the specific contour of which is shown in the corresponding figure respectively on the end of the aspiration stroke, in the other extreme position of the pressure stroke. Based on the dashed contour in the other extreme position, it can also be recognized that, due to the protruding edge 3 of the opening of the feed 6, the displacement element 40 is capable of sealing the inlet 6 and/or outlet 8 of the working chamber 4 in the de-energized state of the coils 41.

(12) The guide members 50a, 50b designed as flat springs 49 are thereby illustrated in FIGS. 1 and 2 deflected in reverse respectively so that the guide members 50a, 50b can bring the mobile part 20 and, moreover, the displacement element back into the extreme position of the pressure stroke again respectively due to their preload. Instead of the guide members 50a, 50b or for their support, this return process can be taken over by the spring 26.

(13) Both in FIG. 1 as well as in FIG. 2, it can be recognized that the measurement and control unit 45 is electrically connected to the coils 41 to be energized that are connected to each other in series on the beginning and end or each individually, the said measurement and control unit 45, at the same time, having a connection to the sensor 46 designed as a Hall sensor. By the alternating winding direction of the coils 41, in the case of serial energization, alternating current directions result within the coils 41. Due to the additional magnetic flux which is generated by the permanent magnets 42 and introduced into the coils 41 via magnetic poles 24, a relative force (Lorentz force) respectively results in the axial direction of the drive 10 between the magnetic poles 24 and the coils 41; the emerging forces sum up in the case of a plurality of coils 41.

(14) In FIG. 3, a guide member 50a can be recognized, which is provided with an approximately circular cross section, the middle recess 51 of which is provided to receive the respective linear body 11, on which the guide member(s) 50a, 50b are set in an axial manner in their inner region 53 while the edge region 54 of which is at least connected to the respective mounting 12 at evenly spaced projections 52. The edge region 54 and interior region 53 are connected to each other by a plurality of curved spring elements 55, which cause the preload force of the flat spring 49 as a spring element 50a, 50b. The force vector of this preload force (not shown) coaxially points toward the linear body 11 (also not shown) into the drawing plan or from this out so that the edge region 54 and the inner region 53 of the flat spring have a different height level.

(15) Accordingly, the presently described invention relates to a pump 1, in particular, an oscillating positive displacement pump, preferably a diaphragm pump, with at least one mobile part 20, which is arranged in a movable manner relative to a fixed part 30, wherein the mobile part 20 is driven and drives a displacement element 40 of the pump 1 itself, wherein the drive 10 is formed by an electrodynamic drive. In order to create a pump 1 with an electrodynamic drive, which has a very direct response behavior, which can carry out a stroke for the displacement element 40 of the pump 1 in both directions by an electrical control system and which is energy-efficient, a plurality of coils 41 and permanent magnets 42 are provided on the drive 10 and the plurality of coils 41 or the plurality of permanent magnets 42 are respectively arranged on the mobile part 20 of the drive 1 and at least one guide member 50a, 50b is provided on the drive 10, which allows the mobile part 20 to move along only one degree of translation freedom.

(16) The oscillating positive displacement pump 1 designed here as a diaphragm pump comprises a measurement and control unit 45 with a data storage and data processor, which processes a position signal of the mobile part as a measured variable and the strength of the drive current as a measured and/or control variable. The pressure in the working chamber of the positive displacement pump 1 is determined from the calculable and subsequently known transmission behavior of the diaphragm by the parameters ‘position’ and ‘current (force)’. In order to determine the pressure in the working chamber 4 of the pump 1, the development of the electrical current over time and the position of the drive 10 is detected as a measured variable and evaluated in order to then determine and to save the pressure in the working chamber 4 based on the calculable transmission behavior. Thereby, the transmission behavior of the diaphragm serving as the displacement element 40 can be described using the formula p=c.sub.1F+c.sub.2x, wherein, in this formula, p is the pressure in the working chamber of the at least one positive displacement pump 1, F is the connecting-rod force and x is the stroke or the position of the working diaphragm and the constants c.sub.1 and c.sub.2 depend on the geometry and the material characteristics of the working diaphragm. In turn, these constants c.sub.1 and c.sub.2 can be determined by the outer clamping radius a as well as the inner clamping radius b of the diaphragm, by the diaphragm thickness and the E-modulus E as well as the Poisson's ratio nu. The transmission behavior of the diaphragm can be recalculated for a plurality of positions and load cases by a numerical calculation method, for example, by a finite-difference or a finite-element method, wherein the values are stored in a table as reference values. Using these values or the interpolations lying in between, the respectively “right” transmission behavior is then determined for calculating the pressure in the working chamber. The measurement and control unit 45, in which the pressure values are stored in a table for a number of positions and load cases, compares the actual and reference values in order to then deduce the transmission behavior between the pressure and the connecting-rod force.

REFERENCE NUMBERS

(17) 1 pump 3 protruding edge of the inlet 4 working chamber 5 pump head 6 inlet 7 inlet valve 8 outlet 9 outlet valve 10 drive 11 linear body 12 mounting 20 mobile part 21 connecting rod 22 rod 23 shell-shaped part 24 pronounced magnetic pole 25 clear cross section 26 spring 30 fixed part 31 housing 40 displacement element (diaphragm) 41 coil 42 permanent magnet 45 measurement/control unit 46 position sensor (Hall sensor) 49 flat spring 50a, b guide member 51 middle recess 52 projection 53 inner region 54 edge region 55 spring element