FIELD OF THE INVENTION
The invention relates to a peristaltic pump to transfer a product, generally liquid, and a method for assembling such a peristaltic pump. The invention also relates to a device for dispensing a liquid product comprising such a pump.
BACKGROUND OF THE INVENTION
The state of the art, in particular document U.S. Pat. No. 5,082,429, already describes a peristaltic pump composed of two parts, one independent of the other, firstly a base carrying a rotor, secondly a head, added on top of the rotor in order to sandwich a dispensing pump between the two parts. The pump comprises a clamping arm used to close the space formed by the two parts and place the rotor in contact with the tube when it is mounted in the pump. The pump is assembled manually. Being sandwiched between the two parts, the dispensing tube can be replaced. The disadvantage of this peristaltic pump is that it is relatively difficult to assemble. Like all peristaltic pumps known in the state of the art, the peristaltic pump as described in this document must be assembled manually, resulting in a long assembly time and a high production cost.
SUMMARY OF THE INVENTION
The invention aims in particular to provide a peristaltic pump whose assembly is facilitated, preferably can be industrialised and in particular automated.
This invention therefore relates to a peristaltic pump comprising:
- a rotor comprising a rotational shaft and configured to be rotated so as to deform a flexible tube,
- a housing comprising a head for receiving the flexible tube and a body for supporting the rotational shaft of the rotor, the rotational shaft being mounted to rotate freely relative to the support body, the receiving head and the support body for the housing being formed as one piece.
Thus, the invention provides for a single part designed to support the rotor and to receive the flexible tube, which means that there is no need to provide for two separate parts to sandwich the flexible tube. Fewer parts therefore need to be assembled and there are fewer assembly steps. Since the pump is easier to assemble, the assembly can be industrialised and in particular automated. The manufacturing cost is therefore reduced. It is understood that two parts formed as one-piece are parts forming a single piece, preferably integral with each other, or even integrally moulded, in other words the head for receiving the flexible tube and the body for supporting the rotational shaft of the rotor are included in the same one-piece part.
According to other optional characteristics of the peristaltic pump taken alone or in combination:
The housing comprises:
- an assembly opening through which the rotor is assembled in the housing and,
- deformable means used to deform the assembly opening and/or a part of the rotor when assembling the rotor.
The deformable means can also be used to enlarge the assembly opening or reduce the width of a part of the rotor, for example of the rotational shaft. In the first case, enlarging the assembly opening allows the rotational shaft of the rotor to go through the opening up to the assembled position. An assembly such as clipping or a force fit is thus possible. No tools or additional steps are required.
- The deformable means comprise a ramp carried by the housing and configured to cooperate with the rotational shaft of the rotor to deform the assembly opening.
The ramp guides the rotational shaft as it moves and facilitates the deformation of the assembly opening. Advantageously, the deformable means comprise two ramps intended to cooperate with the two ends of the rotational shaft to facilitate the deformation of the assembly opening.
- The deformable means comprise a recess used to deform the assembly opening. The recess makes a part of the housing arranged near the recess deformable, thus making it easier to deform the housing. More precisely, the presence of the recess makes it easier to deform the part forming the support body. Assembly of the rotor is therefore facilitated.
It is understood that a recess is a through-hole. Preferably, the shape of the recess follows the ramp to make it even easier to deform the assembly opening.
- The receiving head comprises a cavity configured to receive the flexible tube and a stop to support the flexible tube laterally. Thus, the flexible tube is received and supported only by the one-piece housing, for greater stability and simplified assembly. The fact that the tube is supported by the stop limits the lateral movement generated by the rotor.
It is understood that a lateral support is a support which prevents the displacement of the tube along the axis of rotation of the rotor.
- The receiving head and the support body are integral with each other, and the cavity of the receiving head comprises the stop, which is integral thereof.
- The receiving head comprises two opposite walls integral with each other and forming two stops to support the flexible tube laterally. It is understood that the two opposite walls are walls of the cavity.
- The housing comprises an orifice for receiving the rotational shaft, preferably two orifices arranged on two opposite walls of the housing to form bearings. Thus, the rotational shaft of the rotor is entirely carried by the housing and not by two parts arranged on each side of the rotor and which must be assembled to each other. Preferably, the orifice is configured to allow the rotational shaft to rotate under the action of a drive means of the rotor.
- The peristaltic pump is configured to receive a flexible tube having a fluid inlet and a fluid outlet, the housing comprising means for attaching the fluid inlet and/or the fluid outlet of the flexible tube, for example slots for receiving the fluid inlet and/or the fluid outlet. The attachment means minimise the movement of the flexible tube generated by its deformation. They support the tube in the position and under the tension required for its stability for the fluid to flow when the rotor is moving. This arrangement also increases the lifetime of the tube and prevents a possible leak due to wear. If slots are used, the flexible tube can be attached by clamping.
- The peristaltic pump comprises a flexible tube, the flexible tube comprising complementary attachment means configured to cooperate with the attachment means, the complementary attachment means and the flexible tube preferably being formed as one piece. The complementary attachment means improve the attachment of the tube, while not requiring the assembly of additional components.
- The peristaltic pump comprises at least one added connector, configured to connect the flexible tube to a liquid product reservoir or a liquid product dispensing unit, the connector comprising the complementary attachment means configured to cooperate with the attachment means.
This invention also relates to a method for assembling a peristaltic pump as described previously, comprising the following steps:
- Assembling the flexible tube on the rotor or in the receiving head of the housing,
- Assembling the rotor in the housing,
- Connecting the rotational shaft of the rotor to a drive means.
Optionally, the assembly method also comprises the following steps:
- Deforming the assembly opening and/or a part of the rotor,
- Inserting the rotational shaft of the rotor into the opening up to the assembled position.
The invention further relates to a liquid product dispensing device, comprising:
- A liquid product dispensing unit,
- A liquid product reservoir,
- A peristaltic pump as described previously, connecting the dispensing unit and the reservoir.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood on reading the following description, given solely by way of example and with reference to the accompanying drawings in which:
FIG. 1 is a cross-sectional view of a peristaltic pump according to a first embodiment of the invention;
FIG. 2 is an exploded perspective view of the peristaltic pump of FIG. 1;
FIG. 3 is a cross-sectional and perspective view of a housing of the peristaltic pump of FIG. 1;
FIG. 4 is an exploded perspective view of a peristaltic pump according to a second embodiment of the invention;
FIG. 5 is a perspective view of the assembled peristaltic pump of FIG. 4;
FIG. 6 is an exploded perspective view of a peristaltic pump according to a third embodiment of the invention; and
FIG. 7 is a perspective view of the assembled peristaltic pump of FIG. 6.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1 to 3 show a peristaltic pump according to a first embodiment of the invention, designated by the general reference 1. The peristaltic pump 1 comprises a one-piece housing 10 as shown on FIG. 2. The housing 10 comprises an upper part, forming a head 18 for receiving the flexible tube 30, having the general shape of a half-cylinder, and a lower part forming a support body 19. The lower part forming a support body 19 consists of two opposite vertical walls 191, arranged in the extension of the cylindrical surface of the upper part forming a receiving head 18, and of two opposite lateral walls 192, which are substantially in the same plane as the flat surfaces of the upper part forming a receiving head 18.
The peristaltic pump 1 is configured to receive a flexible tube 30 which is shown on FIGS. 1 and 2. The flexible tube 30 has a fluid inlet 31 and a fluid outlet 32. The fluid inlet 31 is intended to be connected to a liquid product reservoir and the fluid outlet 32 is intended to be connected to a liquid product dispensing unit. Thus, once in operation, the peristaltic pump 1 transfers liquid product from the reservoir to the dispensing unit. In this example, the product dispensed is a medication and dispensing is carried out by injection using a catheter.
The upper part forms a head 18 for receiving the flexible tube 30 and comprises a cavity 181 configured to receive the flexible tube 30. This is shown on FIG. 3 which is a cross-sectional and perspective view of a first half-part of the housing 10 according to a first plane of symmetry P1 of the housing 10. Consequently, it is understood that the cavity 181 has a U-shaped profile according to the first plane of symmetry P1 of the housing 10.
The receiving head 18 further comprises a stop 14 as shown on FIG. 3, supporting the flexible tube 30 laterally. It is understood that this stop 14 is also present on the other half-part of the housing 10 (not shown on this figure).
The peristaltic pump 1 further comprises a rotor 20 comprising a rotational shaft 25 shown on FIG. 2. The rotor 20 is configured to be rotationally driven so as to deform a part of the flexible tube 30 located in the upper part forming a receiving head 18 of the housing 10. Thus, the upper part forms a head 18 of the housing 10 for receiving the flexible tube 30. The rotor 20 comprises three rollers 23 mounted respectively on a rod 24 so that each associated roller can rotate freely. The rotor 20 further comprises a first plate 21 and a second plate 22 mounted on each side of the rollers 23. At least the first plate 21 comprises a hollow 27 at its center intended to cooperate with a drive means 40, as shown on FIG. 2, actuated by an electric motor. For example, the drive means 40 can be a cylinder provided with a protuberance 41 having a shape complementary to that of the hollow 27. Thus, the protuberance 41 on the drive means 40 couples with the hollow 27 of the first plate 21 so that the drive means 40 can rotate the first plate 21 and the entire rotor 20. The first plate 21 and the second plate 22 further comprise holes 26 to receive one end of each rod 24 so that when the rotor 20 is rotated, the first plate 21 and the second plate 22 drive the rods 24 which in turn drive the rollers 23 so that they rotate around the rotational shaft 25.
Each roller 23 is arranged so as to compress a portion of the flexible tube 30 facing it against the receiving head 18 when the peristaltic pump 1 is assembled. Thus, when the rotor 20 rotates, the rollers 23 which block portions of the flexible tube 30 as they rotate will move the liquid product contained in the tube in the same direction. The liquid product at the inlet of the peristaltic pump 1 can then be sucked in due to the elasticity of the flexible tube 30. This is the traditional operation of a peristaltic pump known in the technical field and which will therefore not be described in detail here.
Still referring to FIGS. 1 to 3, the lower part forms a body 19 of the housing 10 for supporting the rotational shaft 25 of the rotor 20, the rotational shaft 25 being mounted to rotate freely relative to the support body 19. To do this, the housing 10 comprises two orifices 11 for receiving the rotational shaft 25, the orifices 11 being arranged on the two lateral walls 192 of the housing 10 to form bearings. The rotor 20 comprises respectively on the first plate 21 and the second plate 22 a disc 211 extending from the first plate 21 or the second plate 22 of diameter substantially equal to that of the orifices 11, each disc 211 cooperating with a corresponding orifice 11 to support the rotor 20 in the support body 19. In the example shown, the disc 211 forms the rotational shaft 25.
As shown on FIGS. 1 to 3, the housing 10 comprises an assembly opening 12 arranged at the end of the support body 19 which is arranged on the side opposite the receiving head 18. The rotor 20 is assembled in the housing 10 through this assembly opening 12. The housing 10 further comprises deformable means 13, 13′ used to deform the assembly opening 12 when assembling the rotor 20. In the example shown, the deformable means 13, 13′ comprise ramps 13 carried by the housing 10, in particular at the support body 19. For example, each ramp 13 is arranged on a vertical wall 191 as shown on FIGS. 2 and 3. The ramps 13 come into contact with the rotational shaft 25 of the rotor 20. When the rotor 20 is forced into the assembly opening 12, the rotational shaft 25 exerts a pressure on the ramps 13, and on the lateral walls 192, tending to push them apart, thus deforming the assembly opening 12 to facilitate the assembly of the rotor 20. In this example illustrated and as shown on FIG. 3, the ramp 13 extends between the assembly opening 12 and the orifice 11.
Advantageously, the deformable means 13, 13′ further comprise recesses 13′ making it easier to deform the assembly opening 12. In the example shown on FIG. 3, each lateral wall 192 comprises two longitudinal recesses 13′ arranged on each side of the orifice 11 and of the ramp 13.
To hold the flexible tube 30 in position as the rotor 20 moves, the housing 10 comprises means 15 for attaching the fluid inlet 31 and the fluid outlet 32 of the flexible tube 30. In the example shown on FIG. 2, the attachment means 15 are receiving slots 15 having a first semi-circular area 151 connected to a second longitudinal area 152. Each receiving slot 15 is arranged on a vertical wall 191 at the assembly opening 12. As shown on FIGS. 1 and 2, the flexible tube 30 comprises complementary attachment means 33 comprising, in this first embodiment, a first cylindrical portion 331 of diameter slightly greater than the width of the second area 152 of the receiving slot 15 for a tight assembly. The complementary attachment means 33 further comprise a second portion 332 having the shape of a disc and connected to the first portion 331. The diameter of the disc formed by the second portion 332 is greater than that of the first area 151 of the receiving slot 15. Each of the first and second portions 331, 332 is connected to the flexible tube 30 and forms one piece with it. In this example, they are integrally molded with the flexible tube 30. The complementary attachment means 33 are arranged at two positions of the flexible tube 30 to cooperate with all the receiving slots 15 present on the housing 10.
When assembling the peristaltic pump 1, the flexible tube 30 is first assembled on the rotor 20 or in the receiving head 18 of the housing 10. The rotor is then assembled in the housing 10 and the rotational shaft 25 of the rotor 20 is connected to the drive means 40, taking care to insert the first portion 331 of the complementary attachment means 33 into the receiving slot 15.
A second embodiment is shown on FIGS. 4 and 5 and only the differences compared with the first embodiment of the invention are described as follows:
In this second embodiment, the complementary attachment means 34 comprise two rings 34 arranged at two positions of the flexible tube 30, the rings 34 and the flexible tube 30 being formed as one piece. In this second embodiment, the attachment means 16 comprise two cavities 16 of shape substantially complementary to that of the ring 34. Thus, when the peristaltic pump 1 is assembled as shown on FIG. 5, each ring 34 is tightly inserted into the cavity 16 to support the flexible tube 30.
A third embodiment is shown on FIGS. 6 and 7 and only the differences compared with the first embodiment of the invention are described as follows:
The peristaltic pump 1 comprises two connectors 50 having a tubular body which are added and connected respectively to the fluid inlet 31 and to the fluid outlet 32. The connectors 50 thus connect the flexible tube 30 to a liquid product reservoir and to a liquid product dispensing unit. Each connector 50 comprises complementary attachment means 35 between the two ends of the connector 50 and extending therefrom. In this third embodiment, the attachment means 17 comprise two cavities 17 of shape substantially complementary to a part, for example half of the complementary attachment means 35. Thus, when the peristaltic pump 1 is assembled as shown on FIG. 7, each complementary attachment means 35 is tightly inserted into the cavity 17 to support the flexible tube 30.
The invention is not limited to the embodiments described and other embodiments will be clearly apparent to those skilled in the art. In particular, it is possible to deform a part of the rotor 20, for example the rotational shaft 25, during the assembly. The rotational shaft 25 can be retractable and retracted when assembling the peristaltic pump in order to insert the rotor 20 into the assembly opening 12.
Patent Application
20220389923
