METHOD OF MANUFACTURING A PUMP, FLUID PUMP, AND DIALYSIS MACHINE

Abstract

A method of manufacturing pumps of different performances for use in a blood treatment device, preferably a dialysis machine, having a pump housing or a pump housing portion for supportingly holding two gear wheels in meshing engagement. The method includes the step of primary shaping of a universal pump housing blank with all features common to the different pumps as well as with such oversizes as to allow machining for manufacturing all different pumps from the same primary-shaped pump housing blank. The method also includes the step of individualizing the universal pump housing blank by machining in the region of the oversizes to achieve the respective performance.

Claims

1. A method of manufacturing pumps, each pump having a unique performance for use in a blood treatment device having a pump housing or a pump housing portion for supportingly holding gear wheels in meshing engagement, the method comprising the steps of: primary shaping of a universal pump housing blank or a universal pump housing portion blank with housing features common to the pumps and with an oversize to allow machining for manufacturing the pumps from the primary-shaped universal pump housing blank or the universal pump housing portion blank; and individualizing the universal pump housing blank or the universal pump housing portion blank by machining in a region of the oversize to achieve the unique performance.

2. The method according to claim 1, wherein during individualizing the universal pump housing blank or the universal pump housing portion blank, receiving pockets for the gear wheels are configured to accommodate the gear wheels, wherein the gear wheels provide the unique performance.

3. The method according to claim 2, wherein the receiving pockets are configured by enlarging or reducing through machining.

4. The method according to claim 2, wherein during individualizing the universal pump housing blank or the universal pump housing portion blank, gear wheel support surfaces of the receiving pockets are machined radially to increase a diameter of the receiving pockets.

5. The method according to claim 2, wherein during the step of individualizing the universal pump housing blank or universal pump housing portion blank, axial inner sides of the receiving pockets are axially machined off in order to increase a depth of the receiving pockets.

6. The method according to claim 2, wherein an axial extension of the universal pump housing blank or the universal pump housing portion blank has the oversize and is shortened by axial machining to axially shorten the receiving pockets.

7. The method according to claim 6, wherein a connecting flange is axially oriented with the universal pump housing blank or the universal pump housing portion blank and is connected to a drive by a mounting flange, and wherein the oversize is configured on the connecting flange of the universal pump housing blank or universal pump housing portion blank and which is axially milled off to reduce the receiving pockets.

8. The method according to claim 7, wherein the connecting flange and the mounting flange are connected to each other exclusively by interposing seals without additional spacer rings.

9. The method according to claim 1, wherein hose grommets are formed during the primary shaping of the universal pump housing blank or the universal pump housing portion blank, the hose grommets being integrally formed with the universal pump housing blank or the universal pump housing portion blank.

10. A method of manufacturing a degassing pump comprising the following steps: primary shaping of a universal pump housing blank or a universal pump housing portion blank; milling of a gear wheel contact surface, bearing fits and a sealing surface into the primary shaped universal pump housing blank or the universal pump housing portion blank; thread cutting of threads for a separating can; and drilling of a receiving pocket for gear wheels.

11. A method of manufacturing a pump, the pump being a dialysis fluid inlet pump for a dialysis machine, the method comprising the following steps: primary shaping of a universal pump housing blank or a universal pump housing portion blank for the pump; milling of a gear wheel contact surface, bearing fits and a sealing surface into the primary shaped universal pump housing blank or the universal pump housing portion blank; thread cutting of threads for a separating can; drilling of a receiving pocket for gear wheels; and boring of channels for a check valve between the receiving pocket and an outer side of the pump.

12. A pump for use in a blood treatment device comprising: a pump housing or a pump housing portion manufactured according to the method of claim 1, the pump housing or the pump housing portion comprising receiving pockets; an electric drive with a rotor mounted or formed on a drive shaft and supported in a drive housing having a mounting flange; and two gear wheels in meshing engagement and in operative engagement with the drive shaft, the two gear wheels sliding against inner sides of the receiving pockets, the pump housing or the pump housing portion being flanged to the mounting flange, in such a way that the drive shaft projects into an interior space of the pump housing or the pump housing portion.

13. The pump according to claim 12, wherein the connecting flange and the mounting flange are connected to each other exclusively by interposing seals without additional spacer rings for individual adjustment of the axial dimension of the receiving pockets.

14. The pump according to claim 12, wherein the two gear wheels are mounted on cylindrical pins that are pressed in the pump housing or the pump housing portion.

15. The pump according to claim 12, wherein the two gear wheels are mounted in the pump housing or the pump housing portion with slide bearings.

16. The pump according to claim 12, wherein the two gear wheels are mounted on a directly sliding solid shaft in the pump housing or the pump housing portion.

17. The pump according to claim 12, wherein the electric drive is an electric motor.

18. The pump according to claim 12, wherein the two gear wheels comprise external teeth which are in meshing engagement.

19. The pump according to claim 12, wherein the two gear wheels comprise a greater diameter gear wheel with internal teeth and a smaller diameter gear wheel with external teeth, the greater diameter gear wheel surrounding the smaller diameter gear wheel, and the smaller diameter gear wheel being arranged eccentrically in the greater diameter gear wheel.

20. A dialysis machine for extracorporeal purification of blood comprising a plurality of pumps manufactured by the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0058] FIG. 1 shows a pump according to the disclosure according to a first embodiment;

[0059] FIG. 2 shows a longitudinal section through the pump according to the disclosure according to FIG. 1;

[0060] FIG. 3a shows an isometric view of a universal pump housing blank;

[0061] FIG. 3b shows a sectional view of the universal pump housing blank in FIG. 3a;

[0062] FIG. 3c shows a sectional view of a pump housing portion for a degassing pump according to the first embodiment;

[0063] FIG. 3d shows a sectional view of a pump housing portion for a dialysis fluid inlet pump according to a second embodiment;

[0064] FIG. 3e shows a sectional view of a pump housing portion for a dialysis fluid outlet pump according to a third embodiment;

[0065] FIG. 4 shows a sectional view through a pump according to the disclosure according to a fourth embodiment;

[0066] FIG. 5 shows a schematic view of a dialysis machine according to the disclosure; and

[0067] FIG. 6 shows a schematic view of two gear wheels in meshing engagement.

DETAILED DESCRIPTION

[0068] Embodiments of the present disclosure are described below based on the accompanying figures.

[0069] FIG. 1 shows a pump 1 according to a first embodiment. The pump 1 according to the first embodiment is in particular a dialysis fluid inlet pump for a blood treatment device, preferably a dialysis machine. The dialysis fluid inlet pump differs from other pumps 1 by a check valve 2, which is screwed to a pump housing or pump housing portion 4 of the pump 1. FIG. 2 shows a longitudinal section through a pump 1 according to the disclosure without the check valve 2. The pump 1 has an electric drive 6, preferably an electric motor. The electric drive 6 has a rotor 8 mounted on a drive shaft 10. The electric drive 6 is connected to a magnetic coupling 12 via the drive shaft 10. The magnetic coupling 12 is mounted within a drive housing 14. A magnetic force-fit connection of the magnetic coupling 12 brings the drive shaft 10 into operative engagement with a first gear wheel 16. The first gear wheel 16 meshes with and drives a second gear wheel 18. The two gear wheels 16, 18 are rotatably mounted in the pump housing or the pump housing portion 4. The pump housing portion 4 has a substantially round base plate 19 with a connecting flange 20. For receiving the gear wheels 16, 18, the pump housing portion 4 forms an (oval) receiving pocket 22 in the base plate 19. The two gear wheels 16, 18 are each rotatably mounted on a cylindrical pin 24, which are pressed into locating bores 26 of the pump housing or pump housing portion 4. The pump housing portion 4 is described in detail below. The connecting flange 20 of the pump housing portion 4 is threaded to a mounting flange 28 of the drive housing 14. For this purpose, the connecting flange 20 has threads 30 prepared to receive screws with which the connecting flange 20 and the mounting flange 28 are screwed together. The pump housing portion 4 and the drive housing 14 are sealed with a separating can 32. The separating can 32 is screwed through the threads 30 between the pump housing portion 4 and the drive housing 14. The two gear wheels 16, 18 are sealed from the magnetic coupling 12 and the interior of the drive housing 14 with a sealing plate 34. The pump 1 is sealed to the outside with a sealing ring 36.

[0070] FIG. 3a shows a universal pump housing blank or universal pump housing portion blank 38 before further processing or machining. The universal pump housing blank 38 has the substantially round base plate 19 with the connecting flange 20 on one side of the base plate 19. Various connections are configured on the opposite side of the connecting flange 20. The universal pump housing blank 38 has two hose grommets 40 for connecting hoses (not shown). Furthermore, the universal pump housing blank 38 has two mounting spigots 42 for screwing on or fixing the check valve 2 and two connection nozzles 44 for connecting the check valve 2. In the universal pump housing blank 38 before further processing, the connection nozzles 44 are not drilled through or open, or respectively are not continuous, i.e. there is no fluid connection between the connection nozzles 44 and the interior of the receiving pocket 22.

[0071] FIG. 3b shows a sectional view of the universal pump housing blank 38 in FIG. 3a. The universal pump housing blank 38 has the two locating bores 26 in which the gear wheels are mounted via the cylindrical pins (not shown in FIG. 3b). The universal pump housing blank 38 furthermore has the receiving pocket 22 for the two gear wheels 16, 18 (not shown in FIG. 3b). The gear wheels 16, 18 are seated on a gear wheel contact surface 46, i.e. the gear wheels 16, 18 slide along the gear wheel contact surface 46 during rotation. The universal pump housing blank 38 is prepared to be converted by machining into one of three variants of the pump housing or pump housing portion 4.

[0072] The three variants are a pump housing portion for a degassing pump 48, a pump housing portion for a dialysis fluid inlet pump 50 and a pump housing portion for a dialysis fluid outlet pump 52. The pump housing portion for the degassing pump 48 shown in FIG. 3c and the pump housing portion for the dialysis fluid outlet pump 52 shown in FIG. 3e differ from each other only in the depth of the receiving pocket 22 for the gear wheels 16, 18. A degassing pump is designed for higher performance than the other pumps 1 and therefore requires gear wheels 16, 18 with a higher gear wheel thickness. For the thicker gear wheels 16, 18, the pump housing portion for the degassing pump 48 has a deeper receiving pocket 22 than the pump housing portion for the dialysis fluid outlet pump 52. The pump housing portion for the dialysis fluid inlet pump 50 is shown in FIG. 3d and has the same dimensions as the pump housing portion for the dialysis fluid outlet pump 52. I.e. the receiving pocket 22 of the pump housing portion for the dialysis fluid inlet pump 50 is as deep as the receiving pocket 21 of the pump housing portion for the dialysis fluid outlet pump 52. One difference in the pump housing portion for the dialysis fluid inlet pump 50 is that one or more thoroughfare channels 54 is or are bored open from the gear wheel contact surface 46 to the connection nozzles 44. Through the thoroughfare channels 54, the gear wheel contact surface 46 is in fluidic contact with the check valve 2 of the dialysis fluid inlet pump.

[0073] FIG. 4 shows a section of a cross-section through a pump 1 according to a further embodiment. Two gear wheels 56, 58 are mounted on slide bearings 60 in the pump housing or pump housing portion 4. For this purpose, only the bearing fits and the wall thicknesses have to be adapted. Here, the gear wheels 56, 58 are not mounted on cylindrical pins as in the first embodiment. Rather, the gear wheels 56, 58 have a protruding stub 61. It is further conceivable to mount the gear wheels 56, 58 on sliding solid shafts (not shown) in the pump housing portion 4. In both variants, lubrication of the bearings has to be ensured.

[0074] FIG. 5 shows a schematic view of a dialysis machine 62 according to the disclosure. The dialysis machine 62 is a blood treatment device for extracorporeal treatment of blood. The dialysis machine 62 comprises a blood circuit and a dialysis fluid circuit. The dialysis fluid circuit has three different pumps 1. The first pump is a degassing pump 64, the second pump is a dialysis fluid inlet pump 66, and the third pump is a dialysis fluid outlet pump 68. The degassing pump 64 is provided to degas the dialysis fluid. The dialysis fluid inlet pump 66 and the dialysis fluid outlet pump 68 are provided for balancing the dialysis fluid during blood treatment. The different pumps 1 each have different requirements. The degassing pump 64 has to deliver a higher performance than the other pumps. That is, the volume flow rate that the degassing pump 64 has to deliver is greater than that of the other pumps. Therefore, the degassing pump 64 has gear wheels 16, 18 with a higher gear wheel thickness. The dialysis fluid outlet pump 68 is identically constructed to the degassing pump 64 except for the gear wheel thickness. The gear wheels 16, 18 of the dialysis fluid outlet pump 68 are thinner than those of the degassing pump 64. The dialysis fluid inlet pump 66 has the same gear wheel thickness as the dialysis fluid outlet pump 68. However, the dialysis fluid inlet pump 66 has the check valve 2, which opens in the event of overpressure and protects the dialysis machine 62 from excessive pressures. In the dialysis fluid inlet pump 66, one or more thoroughfare channels 54 are bored between the receiving pocket 22 of the dialysis fluid inlet pump 66 and the exterior of the pump. The check valve 2 is placed on this thoroughfare channel 54.

[0075] The degassing pump 64 has gear wheels 16, 18 with a width of preferably 10.5 mm. The dialysis fluid outlet pump 68, on the other hand, has gear wheels 16, 18 with a width of preferably 9.5 mm. The additional check valve 2 is attached to the dialysis fluid inlet pump 66, which opens when the pressure is too high and protects the dialysis machine 62 from overload/overpressure. The universal pump housing blank 38 is identical for all pumps 1. The universal pump housing blank 38 only has to be slightly machined for the respective application. For the degassing pump 64, the receiving pocket 22 is milled to a depth of preferably 10.5 mm. For the dialysis fluid outlet pump 68 and the dialysis fluid inlet pump 66, the receiving pocket 22 is milled to a depth of preferably 9.5 mm. For the dialysis fluid inlet pump 66, additional threads 70 are inserted at the mounting spigot 42 and thoroughfare channels 54 to accommodate the check valve 2.

[0076] For the degassing pump 64, the gear wheel contact surface 46, bearing fits and sealing surface are milled into the universal pump housing blank 38. Threads 30 are inserted or cut for mounting the separating can 32. The receiving pocket 22 is drilled out to 10.5 mm. The same machining steps are carried out for the dialysis fluid outlet pump 68 and dialysis fluid inlet pump 66. Only the depth of the receiving pocket is machined to 9.5 mm. Thread 70 is inserted into the outer receptacles of dialysis fluid inlet pump 66 to accommodate the check valve 2, and the thoroughfare channels 54 from gear wheels 16, 18 to the check valve 2 are drilled open.

[0077] FIG. 6 shows the two gear wheels 16, 18 meshing with each other. The two gear wheels 16, 18 are arranged in the pump housing or pump housing portion 4. The fluid, preferably the dialysis fluid, is conveyed by the rotation of the gear wheels 16, 18.

[0078] The object of the disclosure can be solved not only by a gear wheel pump with the gear wheels 16, 18 as fluid delivery device. It is further possible to use a gear ring pump or an internal gear pump. Even with an internal gear pump, the delivery rate of the pump depends on the gear wheel thickness, for example. This means that a universal pump housing blank 38 with variable depth of the receiving pocket for the gear wheels can also be used to vary the output or performance of the internal gear pump.