Hose roller pump

Abstract

A peristaltic pump is described, in particular for delivering a fluid in a device for extracorporeal blood treatment. The invention relates to a peristaltic pump, comprising a pump housing in which a rotor, which can be rotated about a rotor axis, is accommodated, which rotor has at least two pressure elements that are offset from one another in the circumferential direction, and which pump housing has a support surface that extends in an arcuate manner about the rotor axis and is radially spaced apart from the rotor, the support surface is provided for supporting a hose segment that can be introduced radially between the rotor and the support surface. In order to extend the service life of the pump and to reduce fluctuations in the volume of the pump, guide surfaces which rotate together with the rotor are provided, which guide surfaces are arranged and designed adjacent to each other in the circumferential direction on both sides of the pressing element in such a way that the guide surfaces and the support surfaces each form a circular arc-shaped guide channel, the hose segment can be fixed radially in the guide channel with a predetermined clearance fit.

Description

Technical Field

[0001] The invention relates to a hose roller pump or peristaltic pump, i.e. a volumetric pump, in which the medium to be conveyed is squeezed through the hose by external mechanical deformation of the hose. Such pumps are usually used in devices for extracorporeal blood treatment, in particular dialysis machines, for conveying fluids, in particular blood. The fluid is conveyed from the low-pressure side to the high-pressure side by means of a peristaltic pump, wherein an elastically deformable fluid line in the form of a hose segment (the hose segment is also referred to as a pump segment) arranged between the low-pressure side and the high-pressure side is deformed, in particular squeezed, by means of at least two squeezing elements between a support surface of a pump bed and a rotor rotating relative to the support surface. Background Art

[0002] In known peristaltic pumps, such as those known from EP 1 749 549 B1 and as described in Figures 7 to 9 As schematically shown in the figure, two diametrically offset squeezing elements 320 in the form of elastically supported pressure rollers are provided on a rotor 310 having an axis of rotation A, and the support surface 330 is formed by a circular arc surface extending over a sufficiently large central angle of more than 180°.

[0003] In order to fix the hose to a certain extent during operation, the pump segment 360 (see Fig. 9 ), in the center between the two pressure rollers 320 there is a guide surface 340 designed in the shape of a circular arc, which extends over a center angle WZF of approximately 30°. It has been found that this arrangement makes manual insertion of the pump segment more difficult. Summary of the invention

[0004] The object of the present invention is therefore to develop a peristaltic pump of the corresponding type in such a way that the handling is simplified during the manual insertion of the pump segment.

[0005] This object is achieved according to the features of the invention.

[0006] The invention is based on the recognition that, if no special measures are taken to fix the pump segment, the pump segment moves in the pump bed in the opposite direction to the delivery direction during operation of the peristaltic pump, so that the pump segment moves in the pump bed in the opposite direction to the delivery direction. Fig. 9 The rotor is always pulled tighter around the rotor. This can lead to damage to the hose and fluctuations in the delivery volume.

[0007] In order to solve this task, a guide surface is provided which rotates with the rotor, and the guide surfaces are arranged and designed adjacent to each other in the circumferential direction on both sides of the extrusion element, that is, in pairs, so that the guide surface and the support surface respectively construct an arc-shaped guide channel, and the hose segment can be radially fixed in the guide channel with a preset clearance fit. This results in an additional advantage, namely that not only the delivery volume of the pump can be kept constant, but also the pump segment can be "handled" particularly economically during operation. The bending characteristics of the hose are defined by the radius of the guide surface, so that the delivery volume remains constant. At the same time, the guide surface prevents damage to the pump segment. Since the guide surface is only constructed in the vicinity of the extrusion element, the guide contour is divided into a plurality of small areas, thereby reducing the contact surface, which also has a favorable effect on the wear on the hose.

[0008] If the guide surfaces assigned to the extrusion element and adjacent thereto each describe a partial segment of a circle, then in cooperation with the cylindrical or toroidal support surfaces, circularly curved guide channels are formed on both sides of the extrusion element, with which the bending properties of the hose can also be better controlled.

[0009] If the guide surfaces extend over a total center angle which is dimensioned such that a free space extending in the circumferential direction remains between the guide surfaces of adjacent extrusion elements, an additional advantage results, namely that this free space can be used for manual lateral unlocking of the rotor cover or rotor and can be used when inserting a hose segment or pump segment.

[0010] According to an advantageous development, the guide surfaces assigned to the extrusion element extend at different central angles. Preferably, the central angle of the guide surface running behind the extrusion element is larger, so that the hose bend can be better stabilized with as little material consumption as possible.

[0011] Basically, the guide surface can be attached to any component that moves with the rotor. Particular additional advantages are obtained if the guide surface is formed on the rotor cover or is optionally fastened thereto in an exchangeable manner. This is because this provides a particularly large degree of design freedom with equally simple producibility, since such a rotor cover is often formed as a plastic injection molded part.

[0012] Basically, it is possible that the invention is also used for peristaltic pumps in which the pressing elements are placed at a variable angular distance from one another. However, when the pressing elements are arranged offset by 180° from one another, it is advantageous if each two guide surfaces are constructed rotationally symmetrically to one another.

[0013] Advantageously, the guide surface is formed and / or coated with a material having sliding properties that minimize wear. It is also advantageous if the surface of the guide surface is provided with a high surface quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] An exemplary embodiment of the present invention will be explained in more detail below. It is shown that:

[0015] Figure 1 is a perspective view of a peristaltic pump with an open housing cover;

[0016] Figure 2 is based on Figure 1 A three-dimensional view of the rotor of a peristaltic pump;

[0017] Figure 3 It is a top view of the peristaltic pump;

[0018] Figure 3 is a schematic top view of a peristaltic pump according to the invention in a first state at a first point in time of operation,

[0019] Figure 4 is a schematic top view of a peristaltic pump with an inserted pump segment;

[0020] Figure 5 Is the peristaltic pump with Figure 4 Similar schematic top view of a peristaltic pump with a freely cut rotor cover in the area of ​​the extrusion element;

[0021] Figure 6 is a top view of a peristaltic pump with a rotor cover removed;

[0022] Figure 7 is a three-dimensional view of a rotor of a known peristaltic pump;

[0023] Figure 8 is a schematic top view of a known peristaltic pump with an inserted rotor; and

[0024] Fig. 9 The figure shows a top view of a known peristaltic pump with an inserted pump segment.

[0025] Among them: A-rotor axis; WZS-center angle of support surface; WZF-center angle of guide surface; PP-high pressure side; PN-low pressure side; D-rotation direction; FK1-guide contour area; FK2-guide contour area; 5-pump housing; 10-rotor; 20-extrusion element; 30-support surface; 40-rotor base; 41-rocker arm; 42-rotor cover; 44-button; 46-guide surface; WZ46-center angle of guide surface 46; 48-guide surface; WZ48-center angle of guide surface 48; WZG-total center angle of guide surface 46 and guide surface 48; 52-base; 60-pump segment; 70-free space; 310-rotor; 320-extrusion element; 330-support surface; 340-guide surface; 360-pump segment. DETAILED DESCRIPTION

[0026] exist Figure 1 In the figure, reference numeral 1 indicates a peristaltic pump, which is used, for example, in a dialysis machine. The task of the peristaltic pump here is to convey a medium of a defined volume, such as blood or a dialysis fluid, by deformation and clamping of an elastically deformable fluid line. A peristaltic pump for conveying blood usually conveys blood from a negative pressure side PN (low pressure side) to a positive pressure side PP (high pressure side). The peristaltic pump has a pump housing 5, in which a rotor 10 rotatable about a rotor axis A is accommodated, the rotor having at least two extrusion elements 20, here pressure rollers, which are offset to each other in the circumferential direction or along the diameter, and the pump housing having a support surface 30 extending in an arc around the rotor axis A and radially spaced apart from the rotor 20, the support surface being provided for supporting a fluid which can be radially introduced between the rotor 20 and the support surface 30. Figure 1 The support surface 30 is usually formed by a cylinder surface, but the cylinder surface can also be recessed in a groove shape. The direction of rotation of the rotor 10 is indicated by the arrow D when conveying the fluid.

[0027] Figure 2 The rotor 20 is shown in detail. The rotor has Figure 6 4 and 42 are shown in a top view. The rotor 20 can be removed from a drive shaft (not shown in more detail) by means of a laterally operable button 44. The pressing element 20 is rotatably mounted on a rocker arm 41 which is supported on the rotor base 40 in an articulated spring-like manner.

[0028] The rotor cover 42, which rotates together with the rotor 10, carries guide surfaces 46, 48 in the region of the extrusion element 20, wherein one guide surface 46 runs in front of the extrusion element 20 and the other guide surface 48 runs behind the extrusion element 20. Therefore, the guide surfaces 46, 48 are arranged and designed on both sides adjacent to the extrusion element 20 in the circumferential direction, so that the guide surfaces are as shown from Figures 3 to 6 As can be seen in FIG. 1 , corresponding arc-shaped guide channels FK1 and FK2 are formed together with the support surface 30 , in which a hose segment 60 , also called a pump segment, inserted into the pump housing 1 can be radially fixed with a predefined clearance fit.

[0029] By means of the radius of the guide surface, it is possible in this way to Figure 4 and Figure 5 As can be seen in the diagram of , the bending properties of the hose 60 are defined during the operation of the peristaltic pump. The delivery volume can thus be kept constant. At the same time, the guide surface prevents damage to the pump segment 60. Preferably, the guide surfaces 46, 48 are formed and / or coated with a material having sliding properties that minimize wear.

[0030] As can be seen from the figure, the arrangement of the guide surfaces 46, 48 is such that the guide surfaces are only formed near the extrusion element 20, i.e. at a limited angular distance of approximately 20° to 40° for the front-running guide surface 46 or at a limited angular distance of 35° to 60° for the rear-running guide surface 48. In this way, the guide contour is divided into a plurality of small areas that define the guide channels FK1 and FK2, thereby reducing the contact surface, which also has a favorable effect on the wear on the hose 60. With this arrangement, the guide surfaces 46, 48 extend through the total center angle WZG (see Figure 5 ), the total center angle is dimensioned to be limited to, for example, 110° to 140°, so that a free space 70 extending in the circumferential direction remains between adjacent guide surfaces 46 and 48 (see Figure 3 ). This free space 70 can be used in an advantageous manner for manually unlocking the rotor 10 laterally and for inserting a hose or a pump segment 60 .

[0031] In the exemplary embodiment shown, the guide surfaces 46, 48 assigned to the pressing element 20 and adjacent to the pressing element each describe a partial segment of a circle. Figure 5 As shown in , in cooperation with the cylindrical or toroidal support surface 30 , a circularly curved guide channel is produced between the pressing elements 20 , with which the bending properties of the hose 60 can be controlled particularly effectively.

[0032] For the design of the guide surfaces 46, 48, there is a large gap in position, shape and size. In the exemplary embodiment shown, the guide surfaces 46, 48 assigned to the extrusion element 20 extend at different central angles, wherein the guide surface 48 running behind the extrusion element 20 is larger than the guide surface 46 running in front of the extrusion element 20 ( Figure 5 ) extends to a larger central angle WZ48.

[0033] Since, in the peristaltic pump shown, the displacement elements 20 are arranged diametrically offset with respect to one another, the front and rear guide surfaces 46 and 48 are designed rotationally symmetrically with respect to one another.

[0034] Basically, the guide surfaces 46, 48 can be formed on any desired component that is driven along with the rotor 10. In the exemplary embodiment shown, the guide surfaces are formed on the rotor cover 42, which is detachably mounted on the rotor base body 50. The rotor base body 50 is Figure 6 4 is shown in a top view with the rotor cover 42 removed. It can be seen that the base 52 of the rotor base body 50 already has the contours of the guide surfaces 46 , 48 .

[0035] Of course, deviations from the exemplary embodiments shown are possible without departing from the essential idea of ​​the invention.

[0036] Thus, the pressing elements 20 can also be designed, for example, so that they can be positioned at an angle relative to one another in the direction of rotation.

[0037] The components of the peristaltic pump that form the guide surfaces 46, 48 can also be formed integrally with the rotor base body 40 or can also be replaceably mounted on the rotor base body 40 or on the rotor cover 42. Here, the rotor cover 42 can be formed in multiple parts, for example as a 2K part, wherein in this case, the guide surfaces 46, 48 are formed on the insert.

[0038] It is also within the scope of the invention if the rotor has more than two extrusion elements 20, in particular three or four extrusion elements. The angular position of the extrusion elements relative to one another (i.e. the angle between adjacent extrusion elements) outside the scope of pre-compression is preferably 180° in the case of two extrusion elements, 120° in the case of three extrusion elements and 90° in the case of four extrusion elements.

[0039] The pressing element can also be directly formed on the rotor, in particular integrally with the rotor. The pressing element can alternatively be arranged on the rotor arm. These pressing elements are preferably configured to be pivotable in the circumferential direction relative to the rotor, so that pre-compression can be achieved by pivoting in the circumferential direction. The pressing element can be configured in particular as a pressing roller or pressure roller, which rolls on the fluid line in an advantageous manner to protect the material, or as a sliding shoe, which moves in a sliding manner on the fluid line.

[0040] Therefore, the present invention provides a peristaltic pump, in particular for conveying fluid in an extracorporeal blood treatment device, the peristaltic pump having a pump housing, in which a rotor rotatable about a rotor axis is accommodated, the rotor having at least two extrusion elements offset from each other in the circumferential direction, and the pump housing having a support surface extending in an arc shape about the rotor axis and radially spaced from the rotor, the support surface being provided for supporting a hose segment that can be radially introduced between the rotor and the support surface. In order to ensure a constant conveying volume while protecting the hose segment to the greatest extent, the peristaltic pump has a guide surface that rotates together with the rotor, the guide surface being arranged and designed adjacently in the circumferential direction on both sides of the extrusion element, respectively, so that the guide surface and the support surface respectively construct an arc-shaped guide channel, and the hose segment can be radially fixed in the guide channel with a preset clearance fit.

Claims

1. A peristaltic pump, in particular for conveying fluid in an apparatus for extracorporeal blood treatment, the peristaltic pump having A pump housing (5) in which a rotor (10) rotatable about a rotor axis (A) is accommodated, the rotor having at least two extrusion elements (20) offset from one another in the circumferential direction, and the pump housing having a support surface (30) extending in an arc shape about the rotor axis (A) and radially spaced from the rotor (10), the support surface being provided for supporting a hose segment (60) which can be radially introduced between the rotor (10) and the support surface (30), characterized in that Guide surfaces (46, 48) rotating together with the rotor (10) are arranged and designed adjacent to each other in the circumferential direction on both sides of the extrusion element (20) so that the guide surfaces and the support surface (30) respectively form arc-shaped guide channels (FK1, FK2), and the hose segment (60) can be radially fixed in the guide channel with a preset clearance fit.

2. The peristaltic pump according to claim 1, characterized in that: Guide surfaces (46, 48) assigned to the pressing element (20) and adjacent to the pressing element each describe a partial segment of a circle.

3. The peristaltic pump according to claim 1 or 2, characterized in that: The guide surfaces (46, 48) assigned to the extrusion elements (20) extend over a total center angle (WZG) which is dimensioned such that a free space (70) extending in the circumferential direction remains between the guide surfaces (46, 48) of adjacent extrusion elements (20).

4. The peristaltic pump according to claim 3, characterized in that: The free space (70) can be used as a lateral passage for the unlocking button (44).

5. The peristaltic pump according to any one of claims 1 to 4, characterized in that: Guide surfaces (46, 48) assigned to the pressing element (20) extend at center angles (WZ46, WZ48) of different sizes.

6. The peristaltic pump according to any one of claims 1 to 5, characterized in that: The guide surfaces (46, 48) are formed on the rotor cover (42) or are optionally fastened thereto in a replaceable manner.

7. The peristaltic pump according to any one of claims 1 to 6, wherein: The pressing elements (20) are arranged diametrically offset from one another and are characterized in that each two guide surfaces (46, 48) are designed rotationally symmetrically to one another.

8. The peristaltic pump according to any one of claims 1 to 7, characterized in that The guide surfaces (46, 48) are formed and / or coated from a material having sliding properties that minimize wear.

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