metering pump

Abstract

The present invention relates to a metering pump, particularly a micro-metering pump, having a pump chamber (70) in which a fluid inlet (72) is provided at a first valve seat and a fluid outlet (74) is provided at a second valve seat. A control element (30) is coupled to an actuator (22) to move the control element (30) so as to change the volume of the pump chamber (70). The control element (30) is movably mounted by means of a flexible hinge (32).

Description

Technical Field

[0001] The present invention relates to dosing pumps, particularly so-called microdosing pumps, which can be used to dispense extremely small amounts of fluid in a controlled manner. Background Technology

[0002] These micro-metering pumps are particularly used in the medical and pharmaceutical industries, as well as in laboratory technology.

[0003] DE 10 2013 110 029C5 discloses such a metering pump. This metering pump is operated by an electric actuator having a magnet for generating a magnetic field and a control element capable of moving relative to the magnet. The control element includes an energized air-core coil having wire wound multiple times around a non-soft magnetic material, the air-core coil being arranged in the magnetic field and securely connected to a coil carrier made of a non-magnetic material. Here, the control element is mounted to rotate about a rotational axis parallel to the principal direction of the magnetic field. Such a driver is also known as a Lorentz force actuator. Summary of the Invention

[0004] The purpose of this invention is to further develop a metering pump, particularly a micro-metering pump, characterized by low tolerance, repeatable and accurate pumping cycles, and a simple, low-wear design and setup.

[0005] This objective is achieved by a metering pump having: a pump chamber, a fluid inlet opening into the pump chamber at a first valve seat and a fluid outlet exiting the pump chamber at a second valve seat; a control element; and an actuator coupled to the control element to actuate the control element, thereby changing the volume of the pump chamber by moving the control element, and the second valve seat alternately closing and opening to pump fluid from the pump chamber to the fluid outlet. The control element is movably mounted by means of at least one flexible hinge.

[0006] A flexible hinge is defined as a portion of a component with an intentionally reduced cross-section that connects two rigid portions. The significantly reduced cross-section allows adjacent rigid portions to bend and pivot. Here, such a flexible hinge has a force-transmitting effect, or at least a force-bearing effect, and integrally connects two portions capable of moving relative to each other.

[0007] The advantage of using flexible articulations for control elements in metering pumps is that the position of the control elements is precisely specified, resulting in virtually no tolerances during movement, no friction or stick-slip effects, and no clearance in the bearings. This improves pumping accuracy, especially when ensuring a constant metering volume over long periods (many pumping cycles). Furthermore, the chosen design requires fewer parts than in the prior art, simplifying assembly. The metering pump can also have a compact configuration due to the significantly easier implementation of the flexible articulations and the omission of previous multi-part bearing designs.

[0008] A variation of the invention is configured such that the control element includes a freely projecting arm directly hinged to a flexible hinge and an actuating element extending from the arm and acted upon by an actuator. This design allows for a very large lever arm, enabling the actuator to apply high actuating torque through the lever arm, and furthermore, by virtue of the large ratio of the lever arm to the pumping head, simple and precise movement of the diaphragm and low tolerance variation of the pump chamber are possible.

[0009] In particular, the arm and actuation element are angled relative to each other to allow for a compact design and space utilization within the respective housing of the metering pump. The arm and actuation element can also perform different functions.

[0010] For example, the arm and the actuation element can be integrated into each other as a single piece, or the arm and the actuation element can be separate parts connected to each other. In this case, the arm and the actuation element can be directly connected to each other.

[0011] The control element can be coupled to a push rod adjacent to the pump chamber, which is connected to the control element via another flexible hinge. This second flexible hinge ensures that although the push rod pivots about the first flexible hinge, it has little or no lateral movement component as it moves toward and away from the pump chamber, alternatingly increasing and decreasing the volume of the pump chamber. By using two flexible hinges, the movement acting on the pump diaphragm is largely linear.

[0012] Lateral sliding guides are not required for the tappet. This reduces friction and, in particular, avoids the stick-slip effect between moving and stationary parts.

[0013] The actuating element may, for example, have a longitudinal axis that extends substantially parallel to the direction of movement of the pushrod. The term "substantially parallel" is intended to limit the deviation of the direction of movement in opposite directions to no more than 15 degrees. This configuration allows the actuating element to be deflected by the actuator preferably at a right angle to its longitudinal axis. However, due to the lifting mechanism, the movement of the pushrod occurs substantially along the longitudinal axis. This means that the lever's path is essentially L-shaped; the two legs can, of course, take any desired shape, but the moving arms of the double-arm lever meet at the first flexible hinge. The longer lever arm is typically the lever arm of the actuating element, while the shorter lever arm extends to the pushrod, thus creating a force transmission ratio.

[0014] The push rod can be integrally transitioned into a retaining section via another flexible hinge, which is then secured to the control element, specifically to allow for non-destructive disassembly. This means that the push rod is a section of a larger component attached to the control element, and in this case, to the freely protruding arm, by means of the retaining section. Installation to the arm or control element is typically achieved using fastening devices such as locking pins or the like.

[0015] This configuration of the tappet allows it to be manufactured from a particularly suitable material, which can be different from the material used for the control element or the arm. This allows for optimization of the fatigue strength of the other flexible hinge.

[0016] The metering pump is preferably a diaphragm pump, which defines and modulates the pump chamber. Control elements are mechanically connected to the diaphragm, particularly by means of the aforementioned pushrods.

[0017] In particular, the tappet moves almost linearly, allowing for low-fatigue movement of the diaphragm. Furthermore, it is advantageous that the diaphragm moves only perpendicularly to the valve seat forming the plane. In this way, the valve seat opens and closes uniformly, thus preventing any leakage.

[0018] The diaphragm can be sandwiched between an inner portion and an outer portion, where "inner" and "outer" are relative to the housing of the metering pump, meaning the inner portion is located further inside than the outer portion; however, the outer portion does not necessarily define the outer shell of the housing. The outer portion includes a fluid inlet and a fluid outlet, and typically also includes a valve seat; however, the valve seat can also be an integrated portion secured to the fluid inlet and outlet. The inner portion has a retainer for a pushrod, which preferably has a recess larger than the cross-section of the pushrod, creating a lateral clearance between the pushrod and the inner portion to prevent contact. The pushrod attaches its two ends to the diaphragm and another flexible hinge, such that when the actuator is actuated, the pushrod travels along a distinct path of motion.

[0019] Another flexible hinge can be located in the gap between the control element and the internal part, so that there is space available for pivoting movement.

[0020] The control element can extend from the first flexible hinge portion around the inner portion as an angled arm to extend between the actuator and the diaphragm. This allows the first flexible hinge portion to be positioned relative to the diaphragm in virtually any position to achieve the desired lifting movement of the diaphragm and its pushrod.

[0021] According to one embodiment of the invention, the lever arm between the first flexible hinge and the effective center of the actuator is at least three times the lever arm between the first flexible hinge and another flexible hinge, making it possible to have a large transmission ratio in the case of a small metering pump.

[0022] Specifically, the plane defined by at least one valve seat intersects with the first flexible hinge, particularly when both valve seats are located in the same plane. In this way, during the pivoting movement defined by the first flexible hinge, a substantially vertical movement of the portion that closes the valve seat is permitted. In the case of a diaphragm valve with a tappet, the movement of the tappet is substantially perpendicular to this plane.

[0023] More specifically, the actuator is a Lorentz force actuator as described above, and the control element has an air-core coil or a permanent magnet disposed thereon; in particular, one of the air-core coil and the permanent magnet is disposed at the actuating element. Conversely, the other of the air-core coil and the permanent magnet is disposed on the housing side.

[0024] A corresponding check valve can be positioned at each of the fluid inlet and fluid outlet, and the check valve is adapted to open in the same flow direction, i.e., in the pumping direction. Thus, for example, the fluid inlet can be kept open throughout the pumping motion, allowing the check valve to control the inflow.

[0025] Alternatively, the valve seat at the fluid inlet can be closed only at a specific location, such as when the pump is off.

[0026] Specifically, the metering pump includes a resilient reset element, such as a spring, which drives a control element in one direction, causing the control element to move in the opposite direction to that caused by the actuator.

[0027] It has been found that the degree to which the flexible hinge portion has different effects relative to the plane of one or both valve seats or relative to the neutral position of the diaphragm. The flexible hinge portion typically has a rectangular shape in cross-section, more specifically, a rectangular shape in a cross-sectional plane perpendicular to the plane of the valve seat or the neutral position of the diaphragm and simultaneously perpendicular to the pivot axis formed by the flexible hinge portion. The flexible hinge portion has a rectangular shape in this cross-section and can extend perpendicularly, parallelly, or obliquely in the longitudinal direction relative to the plane of one or more valve seats. If the longitudinal direction extends perpendicular to this plane, the hinge portion primarily experiences compressive loads, thereby improving long-term stability. In a parallel orientation, flexural elasticity is improved, while the path in the longitudinal direction oblique to this plane constitutes a trade-off between the aforementioned orientations. Attached Figure Description

[0028] Other features and advantages of the invention will become apparent from the following description and the following drawings, in which:

[0029] Figure 1 A cross-sectional view of an embodiment of a metering pump according to the invention in an unpowered initial position is shown, wherein the metering pump does not allow any fluid to flow through it;

[0030] Figure 2 It shows that it is based on Figure 1 A magnified view of the location of the metering pump in the pump room area;

[0031] Figure 3 It shows that according to Figure 1 A longitudinal cross-sectional view of the metering pump just before the fluid is ejected;

[0032] Figure 4 It shows that it is based on Figure 3 A magnified view of the location of the metering pump in the pump room area;

[0033] Figure 5 An enlarged cross-sectional view of the first flexible hinge portion according to the first variant is shown;

[0034] Figure 6 A perspective cross-sectional view of another embodiment of the first flexible hinge is shown; and

[0035] Figure 7 A three-dimensional cross-sectional view of another embodiment of the first flexible hinge is shown. Detailed Implementation

[0036] Figure 1 The illustration shows a metering pump 10, which in this example is a so-called micro metering pump; however, the metering pump 10 can also be used as a valve.

[0037] In the following text, the directional indications used refer to the correct installation position of the metering pump 10. Here, the metering pump 10 is oriented in the vertical direction H.

[0038] The micro pump 10 has a housing and a base 16, the housing including an end wall 12 that is part of a multi-part canister 14. The canister 14 forms a canister-shaped actuator housing and the base 16 forms a plate-shaped pump seat plate.

[0039] End wall 12 is the upper end of tank 14.

[0040] In addition to the end wall 12, the tank 14 includes a tubular upper portion 18, which in this example is cuboid, and a lower portion 20 fitted into the upper portion 18.

[0041] The actuator 22, which is an electromagnetic actuator and is a Lorentz force actuator, is housed within the housing.

[0042] The actuator 22 includes a plurality of permanent magnets 26, which are mounted in pairs side-by-side to the front portion of the upper portion 18 cut off above the projection plane and to the partially hidden rear portion of the upper portion 18. Thus, the permanent magnets 26 are arranged to be stationary relative to the tank 14 and generate a magnetic field in which the control element 30 can be moved relative to the permanent magnets 26.

[0043] The control element 30 is arranged to pivot within the housing, more specifically about the first flexible hinge 32.

[0044] The flexible hinge portion 32 is a thinner portion of a plate-shaped portion 34 that is laterally positioned below the flange 36 of the lower portion 20. Figure 2 On the right side of the middle and at the level of part 34, the so-called inner part 38 is located below the flange 36 in the right half.

[0045] Located below part 38 is the so-called outer part 40, which also has a plate-like shape and is located below parts 34 and 38 and rests on the base 16.

[0046] In this manner, the plate-shaped portions 34, 38 and 40 are clamped between the flange 36 and the base 16 by the fastening device 43.

[0047] Part 34 extends integrally via a first flexible hinge 32 into an upwardly angled arm 42, which is part of the control element 30.

[0048] The arm 42 extends at an angle or in a curved manner first above the inner portion 38 and then extends above the inner portion 38, thereby forming a shape that can... Figure 2The gap 44 is better seen in the middle.

[0049] The so-called actuating element 46 extends upward from the arm 42. The actuating element 46 is a separate part relative to the arm 42 and is fastened to the arm 42, or the actuating element 46 is integrally extended into the arm 42.

[0050] In the variant shown, the actuating element 46 has a two-part design, wherein two plate-shaped portions are spaced apart along a direction into the projection plane, and the two plate-shaped portions therebetween house and are connected to the arm portion 42.

[0051] An actuating element 46 having two plate-shaped portions extends upward to the actuator and forms a so-called coil carrier 48 there.

[0052] Here, an elliptical, energized air-core coil 50 is attached to a coil carrier 48, thereby enclosing a space 52, which may also include one or more cavities 54. Figure 1 As can be seen, space 52 can also be partially or completely filled with non-magnetic materials, such as plastic materials.

[0053] The energized air-core coil 50 is thus securely attached to the coil carrier 48 and therefore to the control element 30 and moves together with the control element 30.

[0054] The coil carrier 48 is preferably made of a non-soft magnetic material, and therefore the control element 30 is preferably made of a non-soft magnetic material, particularly a suitable plastic material.

[0055] To shield the magnetic field of the permanent magnet 26, the can 14 may be formed as a shielding shell from a suitable material, or alternatively, if a shielding plate is incorporated in the can 14 for shielding the magnetic field, the can 14 may be made of plastic.

[0056] The air-core coil 50 is made of copper wire and is elliptical in shape and elongated relative to the vertical direction H.

[0057] This results in two parallel sections 56 of the air core coil 50, through which current flows in different directions, and these two parallel sections 56 extend parallel to the axis of symmetry C of the air core coil.

[0058] When the air core coil 50 is energized, the charge moving through the winding of the air core coil 50 generates a Lorentz force in the magnetic field of the permanent magnet 26. This Lorentz force causes the control element 30 to pivot about the flexible hinge 32, with its pivot axis extending perpendicular to the projection plane.

[0059] The air core coil 50 may optionally be energized by means of a spring-shaped reset element 60, which, in addition to supplying current, is also used to reset the entire single-arm lever constituted by the control element 30.

[0060] Now that the actuator side of the metering pump 10 has been discussed, the fluid side will be described below.

[0061] The metering pump 10 shown is equipped with... Figure 2 The diaphragm valve has a plate-shaped diaphragm 62 that can be better seen in the middle, and the diaphragm 62 is sandwiched between the inner part 38 and the outer part 40.

[0062] A fluid inlet pipe 66 and a fluid outlet pipe 68 are provided in the base 16, extending into the outer portion 40 and therein to the pump chamber 70. Figure 4 You can see it better in the middle.

[0063] The fluid inlet pipe 66 terminates at the fluid inlet 72 leading to the pump chamber 70, and the fluid outlet 74 forms the starting point of the fluid outlet pipe 68. Check valves 82 and 83 are provided at each of the fluid inlet 72 and fluid outlet 74.

[0064] Fluid inlet 72 and fluid outlet 74 each have a so-called valve seat formed thereon, which, when contacted by diaphragm 62, causes the fluid inlet conduit 66 or fluid outlet conduit 68 to be closed. These two valve seats (typically annular surfaces surrounding fluid inlet 72 and fluid outlet 74) are located... Figure 4 In the common plane E shown.

[0065] exist Figure 4 It can also be seen that the pump chamber 70 is formed in such a way that the upper side of the outer portion 40 facing the inner portion 38 is formed to be slightly concave inward at the lateral edge of the diaphragm 62, and the lower side of the inner portion 38 is also formed to be concave.

[0066] The diaphragm 62 is securely connected, in particular mechanically and form-fittingly connected, to the push rod 78, which in turn extends via another flexible hinge 81 into the retaining section 102, which is received in a suitable opening in the arm 42.

[0067] The retaining segment 102 is securely connected to the arm 42, for example by means of gluing or by different shape fits.

[0068] In the illustrated embodiment, a locking pin 84 is provided that extends through an aligned opening in the arm portion 42, an annular groove in the retaining section 102, and also through two plates forming the actuating element 46, such that multiple parts are connected to the locking pin 84.

[0069] Another flexible hinge 81 is located in the gap 44.

[0070] exist Figure 4 As can be clearly seen, the tappet 78 is not laterally resting against the corresponding edge of its receiving opening in the inner portion 38, thus forming a cylindrical annular gap. In fact, the tappet 78 does not need to be laterally guided in the inner portion 38.

[0071] Figure 4 The first flexible hinge 32 is shown intersecting with plane E.

[0072] According to Figures 1 to 4 In the configuration of the metering pump, the diaphragm 62 is never pressed against the corresponding valve seat at the fluid inlet 72, so that the fluid inlet to the pump chamber 70 is always open, but this does not have to be the case.

[0073] In the initial position, that is, in Figure 1 and Figure 2 In the power-off position shown, the reset element 60 acts on the pivot control element 30, which ensures that the arm 42 occupies a defined, minimum pivot position in which the arm 42 can preferably be largely or completely stress-free in the region of the first flexible hinge 32.

[0074] In the initial position, maintain section 102 and pushrod 78 in the [position]. Figure 2 The visible central axes D and E lie on a common axis, meaning the integral part does not bend in the region of the second flexible hinge 81. The longitudinal axis C extends at a slight angle to axes D and E and to the vertical direction H. In this position, the diaphragm 62 presses against the valve seat at the fluid outlet 74. Although fluid can flow into a portion of the pump chamber 70 via the check valve 83, which is open in this situation, and the fluid inlet 72, fluid cannot flow out.

[0075] When energized, the Lorentz force actuator activates, causing the air core coil 50 at its upper end (as shown) Figure 2(As seen in the image) Pivoting to the left, this means that arm 42 pivots upward in a counterclockwise direction, and in doing so, arm 42 drives retaining section 102 and, via second flexible hinge 81, also drives push rod 78, which in turn causes diaphragm 62 to be lifted. Then, valve seat at fluid outlet 74 opens, allowing fluid to be drawn in by the lifting action, and check valve 83 also opens, while check valve 82 closes to prevent previously pumped fluid from being drawn back from fluid outlet 74.

[0076] At taper 78, it reached its... Figure 4 After the top dead point shown, the current can be shut off again or the polarity of the actuator can be reversed. In either case, a reverse motion occurs, causing arm 42 to pivot downwards and push rod 78 to press down on diaphragm 62. The volume of pump chamber 70 decreases, wherein fluid flows out only through fluid outlet 74 and check valve 82, which is opened in the process, while check valve 83 effectively prevents flow out through fluid inlet 72.

[0077] In the top dead point position, the longitudinal axis C is oriented in the vertical direction H, while the axes D and E are inclined relative to each other, resulting in a small bend in another flexible hinge 81.

[0078] The top dead point can be limited by the adjustable stop 104 to set a limited pumping head (limited pumping volume).

[0079] The first flexible hinge portion 32 has a rectangular shape, which has a cross-section perpendicular to plane E and parallel to the projection plane at this point (see...). Figure 5 It has a longitudinal direction L. According to Figures 1 to 4 In this embodiment, the longitudinal direction L extends parallel to plane E under no-load conditions of the metering pump. According to... Figure 6 In the variant, the longitudinal direction L extends perpendicularly to plane E, and according to Figure 7 In this embodiment, the longitudinal direction L extends obliquely relative to the plane E, preferably within a range of approximately 45 degrees. Each orientation has advantages in terms of the flexibility of the arm 42 and the durability of the flexible hinge 32.

[0080] As is evident from the accompanying drawings, actuator 22 generates movement of control element 30 at its upper end in a horizontal direction, i.e., parallel to plane E; this is merely an exemplary embodiment. However, the movement of push rod 78 occurs approximately perpendicular to plane E, that is, the movement of push rod 78 is approximately at a 90-degree angle to the movement of actuator 22.

[0081] Another advantage of the metering pump shown is that the lever arm of the actuator 22 is significantly larger than the lever arm of the arm 42 that is actuated by the actuator 22 to move the tappet 78, allowing the pump to dispense feed very precisely because the stroke of the actuator 22 is greater than the stroke of the tappet 78. Therefore, the lever arm L1 between the first flexible hinge 32 and the effective center Z (the center of the area of ​​the space limited by the coil) of the actuator 22 is at least three times larger than the lever arm L2 between the first flexible hinge 32 and the second flexible hinge 81 (see [reference]). Figure 3 ).

[0082] It should be understood that although the actuator 22 in the illustrated embodiment is a Lorentz force actuator, the present invention is not limited to this type of actuator. Instead, other actuators, electromagnetic actuators, or other types of actuators may be used.

[0083] The features and variations shown can be combined with each other as needed; furthermore, although these variations and implementations are advantageous, the individual features do not need to be implemented exactly as depicted in the accompanying drawings.

Claims

1. A metering pump, comprising: A pump chamber (70), a fluid inlet (72) opening into the pump chamber (70) at a first valve seat (101), and a fluid outlet (74) exiting the pump chamber (70) at a second valve seat (100); a control element (30); and an actuator (22) coupled to the control element (30) to move the control element (30), thereby changing the volume of the pump chamber (70), and the second valve seat alternately closing and opening to pump fluid from the pump chamber (70) to the fluid outlet (74), wherein the control element (30) is movably mounted by means of at least a first flexible hinge (32). The section is a portion of the component with an intentionally reduced cross-section, which connects two rigid portions and allows adjacent rigid portions to bend and pivot, wherein the control element (30) is coupled to a push rod (78), the push rod (78) being adjacent to the pump chamber (70) and connected to the control element (30) via another flexible hinge (81), wherein the push rod (78) is integrally transitioned into a retaining section (102) via the other flexible hinge (81), the retaining section (102) being fastened to the control element (30), and wherein the metering pump (10) is a diaphragm pump, and the diaphragm (62) defines and modulates the pump chamber (70), the control element (30) being mechanically coupled to the diaphragm (62).

2. The metering pump according to claim 1, characterized in that, The control element (30) includes a free-protruding arm (42) directly hinged to the first flexible hinge and an actuating element (46) extending from the arm and acted upon by the actuator (22).

3. The metering pump according to claim 2, characterized in that, The arm (42) and the actuating element (46) are either integrally connected to each other or are separate parts connected to each other.

4. The metering pump according to any one of the preceding claims, characterized in that, The retaining section (102) is fastened to the control element (30) so that it can be removed in a non-destructive manner.

5. The metering pump according to any one of the preceding claims, characterized in that, The lever arm (L1) between the first flexible hinge (32) and the effective center (Z) of the actuator (22) is at least 3 times the lever arm (L2) between the first flexible hinge (32) and the other flexible hinge (81).

6. The metering pump according to any one of the preceding claims, characterized in that, The control element (30) is mechanically connected to the diaphragm (62) by means of a push rod (78).

7. The metering pump according to any one of the preceding claims, characterized in that, The diaphragm (62) is sandwiched between an inner portion (38) and an outer portion (40), wherein the outer portion includes the fluid inlet (72) and the fluid outlet (74) and the inner portion (38) has a retainer (90) for the push rod (78).

8. The metering pump according to claim 7, characterized in that, The other flexible hinge (81) is located in the gap (44) between the control element (30) and the internal part (38).

9. The metering pump according to claim 7 or 8, characterized in that, The control element extends from the first flexible hinge (32) around the inner portion (38) as an angled arm to extend between the actuator (22) and the diaphragm (62).

10. The metering pump according to any one of the preceding claims, characterized in that, The first flexible hinge (32) intersects with the plane (E) defined by the neutral position of the diaphragm or at least one valve seat (100, 101).

11. The metering pump according to any one of the preceding claims, characterized in that, The actuator (22) is a Lorentz force actuator, and an air core coil (50) or a permanent magnet is provided at the control element (30).

12. The metering pump according to any one of the preceding claims, characterized in that, A corresponding check valve (82, 83) is located at each of the fluid inlet (72) and the fluid outlet (74).

13. The metering pump according to any one of the preceding claims, characterized in that, The first flexible hinge portion (32) has an elliptical shape in cross-section, and the first flexible hinge portion (32) extends vertically, parallel or obliquely relative to the plane (E) defined by the neutral position of the diaphragm or at least one valve seat along its longitudinal direction (L).

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