Medical pumps and infusion devices

Abstract

A fixed amount of the drug solution is supplied to suppress the pulsating flow of the drug solution. [Solution] The medical pump comprises a fluid delivery unit and a drive unit. The fluid delivery unit delivers the drug solution. The drive unit drives the fluid delivery unit. As the first rotor 140 rotates, the drug solution present in the fluid delivery space is delivered by the protrusions 143 located in the fluid delivery space among the plurality of protrusions 143. The first rotational speed of the first rotor 140 and the second rotor 150 in the first term T1, from the time the protrusion 143 begins to enter the recess 153 when the corresponding protrusion 143 and recess 153 engage, to the time the entry is completed, is lower than the second rotational speed of the first rotor 140 and the second rotor 150 in the second term T2, other than the first term T1.

Description

[Technical Field]

[0001] The present invention relates to a medical pump and an infusion device. [Background Art]

[0002] As a prior art document disclosing the configuration of a blood purification system, there is Japanese Patent Laid-Open No. 2012-200275 (Patent Document 1). The blood purification system described in Patent Document 1 includes a blood purification apparatus. The blood purification apparatus includes a blood purifier and a purification fluid circuit. The purification fluid circuit has a tubular purification fluid supply channel connected to a purification fluid bag. A tube pump is provided in the purification fluid supply channel. By driving the tube pump, the purification fluid in the purification fluid bag is supplied to the blood purifier through the purification fluid supply channel.

[0003] As a prior art document disclosing the configuration of a gear pump, there is Japanese Patent Laid-Open Publication No. Sho 52-60404 (Patent Document 2). The gear pump described in Patent Document 2 includes a casing and a pair of rotors. The pair of rotors are arranged inside the casing. A convex portion is formed on the outer peripheral surface of one rotor of the pair of rotors. A concave portion is formed on the outer peripheral surface of the other rotor of the pair of rotors. The fluid inside the casing is transported when the pair of rotors rotate while the convex portion and the concave portion synchronously mesh with each other. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Laid-Open No. 2012-200275 [Patent Document 2] Japanese Patent Laid-Open Publication No. Sho 52-60404 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] In the blood purification system described in Patent Document 1, the diameter of the tubes forming the drug solution flow path may change over time due to repeated operation of the tube pump, potentially preventing the supply of a consistent amount of drug solution.

[0006] When the gear pump described in Patent Document 2 is applied to a medical pump, the drug solution accumulates in the recesses of the rotor. As the rotor rotates, the drug solution accumulated in the recesses of the rotor flows into the fluid delivery path, which can cause fluctuations in the supply amount of the drug solution and potentially generate pulsating flow.

[0007] The present invention has been made to solve the above problems and aims to provide a medical pump and infusion device that can supply a fixed amount of drug solution and suppress the pulsating flow of the drug solution. [Means for solving the problem]

[0008] A medical pump according to the present invention comprises a fluid delivery unit and a drive unit. The fluid delivery unit delivers a drug solution. The drive unit drives the fluid delivery unit. The fluid delivery unit includes a housing and a pump unit. The pump unit is located inside the housing. The pump unit has a first rotating shaft, a second rotating shaft, a first rotor, and a second rotor. The first rotating shaft is connected to the drive unit, driven by the drive unit, and extends in a first direction. The second rotating shaft is connected to the drive unit, driven by the drive unit, and extends parallel to the first rotating shaft in a first direction. The first rotor is rotatable in the circumferential direction of the first rotating shaft in conjunction with the rotation of the first rotating shaft. The second rotor is rotatable in the circumferential direction of the second rotating shaft in conjunction with the rotation of the second rotating shaft. The first rotor has a plurality of protrusions. The plurality of protrusions are formed by a portion of the first outer surface of the first rotor protruding radially from the first rotor. The second rotor is provided with a plurality of recesses. Multiple recesses are formed by a portion of the second outer surface of the second rotor being recessed radially. The first and second rotors are synchronously rotatable such that the corresponding protrusions and recesses among the multiple protrusions and recesses interlock. A liquid delivery space is provided between the inner surface of the housing and the first outer surface. Each of the multiple protrusions slides against the inner surface when the first rotor rotates. As the first rotor rotates, the protrusions in the liquid delivery space among the multiple protrusions deliver the liquid present in the liquid delivery space. The first rotational speed of the first and second rotors in the first term, from the start to the end of entry of a protrusion into a recess when a corresponding protrusion and recess interlock, is lower than the second rotational speed of the first and second rotors in the second term, excluding the first term.

[0009] A medical pump according to the present invention comprises a fluid delivery unit and a drive unit. The fluid delivery unit delivers a drug solution. The drive unit drives the fluid delivery unit. The fluid delivery unit includes a housing and a pump unit. The pump unit is located inside the housing. The pump unit has a first rotating shaft, a second rotating shaft, a first rotor, and a second rotor. The first rotating shaft is connected to the drive unit, driven by the drive unit, and extends in a first direction. The second rotating shaft is connected to the drive unit, driven by the drive unit, and extends parallel to the first rotating shaft in a first direction. The first rotor is rotatable in the circumferential direction of the first rotating shaft in conjunction with the rotation of the first rotating shaft. The second rotor is rotatable in the circumferential direction of the second rotating shaft in conjunction with the rotation of the second rotating shaft. The first rotor has a plurality of protrusions. The plurality of protrusions are formed by a portion of the first outer surface of the first rotor protruding radially from the first rotor. The second rotor is provided with a plurality of recesses. Multiple recesses are formed by a portion of the second outer surface of the second rotor being recessed radially. The first and second rotors are synchronously rotatable such that the corresponding protrusions and recesses among the multiple protrusions and recesses interlock. A liquid delivery space is provided between the inner surface of the housing and the first outer surface. Each of the multiple protrusions slides against the inner surface when the first rotor rotates. As the first rotor rotates, the protrusions in the liquid delivery space among the multiple protrusions deliver the liquid present in the liquid delivery space. The first rotational speed of the first and second rotors in the third term, from the start of entry of a protrusion into a recess to the end of exit when the corresponding protrusion and recess interlock, is lower than the second rotational speed of the first and second rotors in the fourth term, excluding the third term.

[0010] The infusion device according to the present invention comprises the above-mentioned medical pump, a downstream tube, and an upstream tube. The downstream tube is provided downstream of the medical pump and constitutes the downstream path of the drug solution. The upstream tube is provided upstream of the medical pump and constitutes the upstream path of the drug solution. [Effects of the Invention]

[0011] According to the present invention, a constant amount of drug solution can be supplied, and the pulsating flow of the drug solution can be suppressed. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing the configuration of an infusion device according to one embodiment of the present invention. [Figure 2] This is a partial cross-sectional view showing the configuration of a medical pump according to one embodiment of the present invention. [Figure 3] Figure 2 is a partial cross-sectional view of the medical pump configuration as seen from the direction of the arrow III-III. [Figure 4] This is a circuit diagram showing the configuration of an infusion device according to one embodiment of the present invention. [Figure 5] This is a perspective view showing the connection structure between the rotor's rotation axis and the drive unit's gear axis in a medical pump. [Figure 6] This is a perspective view showing the connection between the fluid delivery unit and the drive unit in a medical pump. [Figure 7] This is a top view showing the configuration of the rotor in a medical pump. [Figure 8] This is a partial cross-sectional view showing the state just before the convex portion of the first rotor and the concave portion of the second rotor engage. [Figure 9] This is a schematic diagram showing the relationship between the rotational positions of the convex portion of the first rotor and the concave portion of the second rotor and each term. [Figure 10] This is a schematic diagram showing the relationship between the rotational positions of the convex portion of the first rotor and the concave portion of the second rotor and each term, according to a second modified example of one embodiment of the present invention. [Figure 11] This is a partial cross-sectional view showing the configuration of a medical pump according to a third modified example of one embodiment of the present invention. [Modes for carrying out the invention]

[0013] Hereinafter, a medical pump and infusion device according to one embodiment of the present invention will be described with reference to the drawings. In the following description of the embodiment, the same or corresponding parts in the figures will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0014] In the drawings, the direction in which the first rotor and the second rotor are arranged in parallel is defined as the X direction, the direction in which the rotation axes of the first rotor and the second rotor extend is defined as the Y direction serving as a first direction, and the vertical direction is defined as the Z direction. In addition, in the drawings, there are portions where illustration of connection structures between respective components and the like is omitted. Furthermore, in the drawings, for convenience, the configurations of the first rotor and the second rotor, which will be described later, are not shown as cross-sectional views.

[0015] In the following description of embodiments, a blood purification apparatus, which is an infusion apparatus, will be described as a configuration example. The blood purification apparatus in this case can employ any one of the following methods: Continuous Renal Replacement Therapy (CRRT), Continuous Hemodiafiltration (CHDF), Continuous Hemofiltration (CHF), Continuous Hemodialysis (CHD), and Slow Continuous Ultrafiltration (SCUF).

[0016] First, the configuration of the infusion apparatus will be described. FIG. 1 is a schematic diagram showing the configuration of an infusion apparatus according to an embodiment of the present invention. As shown in FIG. 1, an infusion apparatus 1 according to an embodiment of the present invention includes an apparatus main body 10, a medical pump 20, a tube 30, and an air bubble sensor 40.

[0017] The apparatus main body 10 is a part to which other components of the infusion apparatus 1 are attached or accommodated. A circuit through which a body fluid such as a patient's blood or drained fluid from a blood purifier flows can be attached to the apparatus main body 10. In addition, the apparatus main body 10 accommodates a control unit which will be described later. The control unit controls the operations of pumps and valves attached to these circuits.

[0018] The main body of the device 10 includes a display unit (not shown). The display unit is located at the top of the main body of the device 10. Information regarding the infusion device 1 is output to the screen of the display unit.

[0019] The main body of the device 10 further includes a mounting section (not shown). The mounting section allows for the attachment of a container, such as a liquid medicine bag containing a liquid medicine, above the display section.

[0020] The medical pump 20 is installed on a circuit through which bodily fluids such as the patient's blood, or drainage fluid from a blood purifier, flows. In this embodiment, the medical pump 20 functions, for example, as a medical pump that supplies dialysis fluid to a blood purifier (not shown). The medical pump 20 is attached to the outer wall of the main body 10 of the device. The detailed configuration of the medical pump 20 will be described later.

[0021] Tube 30 forms a pathway through which the drug solution flows. Tube 30 includes an upstream tube 31 and a downstream tube 32.

[0022] The upstream tube 31 is located upstream of the medical pump 20. The upstream tube 31 constitutes the upstream path for the drug solution. The downstream tube 32 is located downstream of the medical pump 20. The downstream tube 32 constitutes the upstream path for the drug solution.

[0023] The bubble sensor 40 is composed of a pair of transmitting and receiving units. The bubble sensor 40 is provided at a predetermined position on the main body 10 of the device. In the bubble sensor 40 of this embodiment, the pair of transmitting and receiving units are provided so as to sandwich the downstream tube 32 from a direction that intersects the flow direction of the chemical solution.

[0024] The bubble sensor 40 detects the presence or absence of bubbles in the upstream path within the upstream tube 31 or in the downstream path within the downstream tube 32. In this embodiment, the bubble sensor 40 detects the presence or absence of bubbles in the downstream path within the downstream tube 32. This helps to prevent bubbles from entering the patient's body. The bubble sensor 40 also detects the presence or absence of the drug solution. The bubble sensor 40 may also be configured to detect the presence or absence of bubbles in the upstream path within the upstream tube 31.

[0025] Next, the configuration of the medical pump 20 will be described. Figure 2 is a partial cross-sectional view showing the configuration of a medical pump according to one embodiment of the present invention. Figure 3 is a partial cross-sectional view of the configuration of the medical pump in Figure 2, viewed from the direction of the arrow III-III.

[0026] As shown in Figures 2 and 3, a medical pump 20 according to one embodiment of the present invention comprises a fluid delivery unit 50, a drive unit 60, and a motor unit 70.

[0027] The liquid delivery unit 50 delivers the chemical solution. The liquid delivery unit 50 includes a housing 100 and a pump unit 110.

[0028] The housing 100 forms the outer shape of the liquid delivery unit 50. The housing 100 has a substantially elliptical shape when viewed from the Y direction, with its major axis aligned with the X direction, in accordance with the shape of the pump unit 110. However, the shape of the housing 100 is not limited to a substantially elliptical shape.

[0029] The housing 100 is provided with an internal space 101. The pump unit 110 is located in the internal space 101.

[0030] The housing 100 has a first inner surface 102 and a second inner surface 103. The first inner surface 102 and the second inner surface 103 face the internal space 101. The first inner surface 102 is located on one end side in the X direction of the internal space 101 when viewed from the Y direction. The second inner surface 103 is located on the other end side in the X direction of the internal space 101 when viewed from the Y direction.

[0031] The pump unit 110 is located inside the housing 100. When viewed from the Y direction, the pump unit 110 is positioned in the internal space 101 so as to face the first inner surface 102 and the second inner surface 103.

[0032] The pump section 110 includes a first rotating shaft 120, a second rotating shaft 130, a first rotor 140, and a second rotor 150.

[0033] The first rotation axis 120 extends in a first direction (Y direction). The first rotation axis 120 has a first axis 121 that is aligned with the first direction (Y direction). The first rotation axis 120 is rotatable about the first axis 121.

[0034] The first rotating shaft 120 is connected to the drive unit 60. The first rotating shaft 120 is driven by the drive unit 60. The first rotating shaft 120 is rotatably driven by bearings located inside the housing 100.

[0035] The second rotation axis 130 extends in parallel with the first rotation axis 120 in the first direction (Y direction). The second rotation axis 130 has a second axis 131 along the first direction (Y direction). The second rotation axis 130 is rotatable about the second axis 131.

[0036] The second rotating shaft 130 is connected to the drive unit 60. The second rotating shaft 130 is driven by the drive unit 60. The second rotating shaft 130 is rotatably driven by bearings located inside the housing 100.

[0037] The first rotor 140 is a rotating body located in the internal space 101 of the housing 100. The first rotor 140 has a first main body portion 141 and a first outer peripheral surface 142.

[0038] The first main body portion 141 has a substantially cylindrical shape with its axial direction aligned in the first direction (Y direction). The first main body portion 141 has a through hole in its central part that extends through in the first direction (Y direction). The first rotating shaft 120 is inserted through this through hole, and the first main body portion 141 is fixed to the first rotating shaft 120. As a result, the first rotor 140 can rotate in the circumferential direction of the first rotating shaft 120 in conjunction with the rotation of the first rotating shaft 120. The method of fixing the first rotor 140 to the first rotating shaft 120 may be fitting or joining, and is not particularly limited.

[0039] The first outer peripheral surface 142 is located at the periphery of the first main body portion 141 in the circumferential direction in the first direction (Y direction). The first rotor 140 has a plurality of protrusions 143. The plurality of protrusions 143 are formed by a portion of the first outer peripheral surface 142 of the first rotor 140 protruding radially from the first rotor 140.

[0040] In this embodiment, the multiple protrusions 143 are composed of two protrusions 143. However, there may be three or more protrusions 143.

[0041] In this embodiment, the two protrusions 143 are provided at opposing positions on the first outer peripheral surface 142 with respect to the first axis 121. It is desirable that the multiple protrusions 143 are arranged at equal intervals from each other in the circumferential direction of the first outer peripheral surface 142. This allows the liquid delivery space, described later, to be divided into multiple uniform spaces, thereby enabling the delivery of a uniform amount of liquid.

[0042] The second rotor 150 is a rotating body located in the internal space 101 of the housing 100. The second rotor 150 has a second main body portion 151 and a second outer peripheral surface 152.

[0043] The second main body portion 151 has a substantially cylindrical shape with its axial direction aligned with the first direction (Y direction). The second main body portion 151 has a through hole in its central part that extends through along the first direction (Y direction). The second rotating shaft 130 is inserted through this through hole, and the second main body portion 151 is fixed to the second rotating shaft 130. As a result, the second rotor 150 can rotate in the circumferential direction of the second rotating shaft 130 in conjunction with the rotation of the second rotating shaft 130. The method of fixing the second rotor 150 to the second rotating shaft 130 may be fitting or joining, and is not particularly limited.

[0044] The second outer peripheral surface 152 is located at the periphery of the second main body portion 151 in the circumferential direction in the first direction (Y direction). The second rotor 150 is provided with a plurality of recesses 153. The plurality of recesses 153 are formed by a portion of the second outer peripheral surface 152 of the second rotor 150 being recessed in the radial direction of the second rotor 150.

[0045] In this embodiment, the multiple recesses 153 are composed of two recesses 153. The number of recesses 153 may be three or more. Furthermore, the number of recesses 153 is at least greater than the number of protrusions 143. It is desirable that the number of recesses 153 be the same as the number of protrusions 143.

[0046] In this embodiment, the two recesses 153 are provided at opposing positions on the second outer peripheral surface 152 with respect to the second axis 131. It is desirable that the multiple recesses 153 are arranged at equal intervals from each other in the circumferential direction of the second outer peripheral surface 152, in accordance with the arrangement of the corresponding protrusions 143.

[0047] At least one of the housing 100, the first rotor 140, and the second rotor 150 is made of a resin material including a polypropylene resin. In this embodiment, all of the housing 100, the first rotor 140, and the second rotor 150 are made of a resin material including a polypropylene resin.

[0048] A resin material containing a polypropylene-based resin is, for example, a resin composition comprising at least a polypropylene-based resin, silicone-grafted polypropylene, and silicone oil, wherein the silicone-grafted polypropylene is obtained by grafting polypropylene with at least one selected from the group consisting of polydimethylsiloxane, polymethylphenylsiloxane, and polydiphenylsiloxane. The resin material used for the housing 100, the first rotor 140, or the second rotor 150 is not limited to the resin material containing the polypropylene-based resin described above.

[0049] As shown in Figure 3, the drive unit 60 drives the fluid supply unit 50. The drive unit 60 includes a gear housing 61, a first gear 63, a second gear 64, a first gear shaft 65, and a second gear shaft 66.

[0050] The gear housing 61 forms the outer shape of the drive unit 60. A storage space 62 is provided inside the gear housing 61.

[0051] The first gear 63 and the second gear 64 are arranged inside the housing space 62. The first gear 63 and the second gear 64 are aligned in the X direction. The first gear 63 and the second gear 64 are arranged so that their gear portions mesh with each other in the circumferential direction in the first direction (Y direction).

[0052] The first gear shaft 65 is connected to the first gear 63. The first gear shaft 65 is aligned with the first rotation shaft 120 in the first direction (Y direction). The first gear shaft 65 is rotatable by bearings located inside the gear housing 61.

[0053] The second gear shaft 66 is connected to the second gear 64. The second gear shaft 66 is aligned with the second rotation shaft 130 in the first direction (Y direction). The second gear shaft 66 is rotatable by bearings located inside the gear housing 61.

[0054] The motor unit 70 is connected to the drive unit 60. In this embodiment, the motor unit 70 is connected to the first gear shaft 65. When the motor unit 70 is driven, the first gear shaft 65 and the first gear 63 rotate in the circumferential direction of the first direction (Y direction). Since the second gear 64 meshes with the first gear 63, the first gear 63 is rotationally driven, and the second gear 64 and the second gear shaft 66 also rotate in the circumferential direction of the first direction (Y direction).

[0055] As shown in Figure 2, when the medical pump 20 is driven, the first rotor 140 rotates clockwise when viewed from the Y direction. On the other hand, the second rotor 150 rotates counterclockwise. The first rotor 140 and the second rotor 150 rotate in opposite directions due to the meshing of the first gear 63 and the second gear 64 in the drive unit 60.

[0056] Furthermore, the motor unit 70 is not limited to a single unit. The motor unit 70 may have two motor units, each connected to a corresponding gear shaft.

[0057] The first rotor 140 and the second rotor 150 are synchronously rotatable such that corresponding protrusions 143 and recesses 153 among the multiple protrusions 143 and multiple recesses 153 interlock.

[0058] When the first rotor 140 and the second rotor 150 rotate, that is, when the medical pump 20 is driven, the drug solution flows through the internal space 101. The internal space 101 includes an inhalation space 104, a fluid delivery space 105, and a discharge space 106.

[0059] The intake space 104 is located at one end of the internal space 101 in the Z direction. The intake space 104 is connected to the upstream path of the upstream tube 31.

[0060] The liquid delivery space 105 is located at one end of the internal space 101 in the X direction. The liquid delivery space 105 is provided between the first inner circumferential surface 102 of the housing 100 and the first outer circumferential surface 142 of the first rotor 140. The liquid delivery space 105 is connected to the suction space 104 and the discharge space 106.

[0061] The liquid delivery space 105 is divided into at least two spaces by each of the multiple protrusions 143. In this embodiment, the liquid delivery space 105 is divided into a first liquid delivery space 107 and a second liquid delivery space 108 by the protrusions 143, in the state of the rotation angles of the first rotor 140 and the second rotor 150 shown in Figure 2.

[0062] The number of compartments in the liquid delivery space 105 varies according to the number of protrusions 143. While the first rotor 140 is in operation, at least one protrusion 143 is always located within the liquid delivery space 105. This configuration prevents a situation where no protrusions 143 are located within the liquid delivery space 105, causing the chemical solution to continue flowing through the space.

[0063] Each of the multiple protrusions 143 slides against the first inner surface 102 when the first rotor 140 rotates. This ensures that the liquid delivery space 105 is sealed. Furthermore, the protrusion height of the protrusions is low, preventing them from contacting the first inner surface 102 and thus preventing any impairment of the pump's function.

[0064] The discharge space 106 is located on the other end side in the Z direction of the internal space 101. The discharge space 106 is connected to the downstream path of the downstream tube 32. The suction space 104 and the discharge space 106 are indirectly connected via the fluid delivery space 105. In other words, the suction space 104 and the discharge space 106 are not directly connected.

[0065] It is desirable that the sum of the radii of the first rotor 140 and the radii of the second rotor 150 remain constant at any position in the rotation angle. This helps to suppress leakage of the chemical solution between each component in the internal space 101, or uneven wear between the first rotor 140 and the second rotor 150.

[0066] It is desirable that the sum of the radii of the first rotor 140 and the radii of the second rotor 150 be set to be greater than the distance between the first axis 121 and the second axis 131. In this case, the sum of the radii of the first rotor 140 and the radii of the second rotor 150 is set within the range of elastic deformation of the first rotor 140 and the second rotor 150. This makes it possible to suppress leakage of the chemical solution between each component in the internal space 101.

[0067] It is desirable that the radius of the outermost part of each of the multiple protrusions 143 is larger than the inner diameter of the first inner surface 102. This ensures that the first rotor 140 can be reliably brought into sliding contact with the first inner surface 102, thereby suppressing leakage of the chemical solution between the housing 100 and the first rotor 140 in the internal space 101. In addition, even if a portion of the protrusions 143 is worn away due to wear at the tip of the protrusions 143 and mixes with the chemical solution, a filter (not shown) may be provided on the downstream path to remove the worn portion of the protrusions 143.

[0068] It is desirable that the radius of the portion of the second outer circumferential surface 152 excluding the multiple recesses 153 be larger than the inner diameter of the second inner circumferential surface 103. This ensures that the second rotor 150 can be reliably brought into sliding contact with the second inner circumferential surface 103, thereby suppressing leakage of the chemical solution between the housing 100 and the second rotor 150 in the internal space 101.

[0069] Figure 4 is a circuit diagram showing the configuration of an infusion device according to one embodiment of the present invention. As shown in Figure 4, the infusion device 1 according to one embodiment of the present invention further comprises a control unit 80 and a connection detection sensor 85.

[0070] The control unit 80 and the connection detection sensor 85 are built into the main body 10 of the device. The connection detection sensor 85 detects the connection between the first rotating shaft 120 and the first gear shaft 65, or the connection between the second rotating shaft 130 and the second gear shaft 66.

[0071] The control unit 80 is electrically connected to the bubble sensor 40, the motor unit 70, and the connection detection sensor 85. For example, when a bubble is detected by the bubble sensor 40, the control unit 80 can receive a detection signal from the bubble sensor 40 and stop the motor unit 70 from driving. The control unit 80 can also, for example, receive a non-detection signal from the connection detection sensor 85 and maintain the state in which the motor unit 70 does not drive.

[0072] The following describes the delivery of the drug solution in the infusion device 1. The following description assumes that the priming process, which fills the drug solution's distribution path, has been completed.

[0073] In the rotational positions of the first rotor 140 and the second rotor 150 shown in Figure 2, the suction space 104 and the first liquid delivery space 107 are in communication. When the pump unit 110 is driven, the protrusion 143 in the liquid delivery space 105 slides clockwise against the first inner circumferential surface 102. As the protrusion 143 moves, the amount of liquid medicine received into the first liquid delivery space 107 increases, so that after the liquid medicine is drawn into the suction space 104 from the upstream path in the upstream tube 31, the liquid medicine flows from the suction space 104 into the first liquid delivery space 107.

[0074] As the first rotor 140 rotates, the liquid chemical present in the liquid delivery space 105 is delivered by the protrusion 143 located in the liquid delivery space 105 among the multiple protrusions 143.

[0075] Specifically, when the pump unit 110 is driven, the first fluid delivery space 107 becomes a closed space surrounded by the first outer peripheral surface 142, the first inner peripheral surface 102, and the multiple protrusions 143. When the pump unit 110 is driven again, the first fluid delivery space 107 communicates with the discharge space 106. The drug solution in the first fluid delivery space 107 flows into the discharge space 106. The drug solution that flows into the discharge space 106 is discharged to the blood purifier from the downstream path in the downstream tube 32.

[0076] Similar to the first fluid delivery space 107, when the pump unit 110 is driven, the second fluid delivery space 108 becomes a closed space surrounded by the first outer peripheral surface 142, the first inner peripheral surface 102, and the multiple protrusions 143. Subsequently, the second fluid delivery space 108 communicates with the discharge space 106. The drug solution in the second fluid delivery space 108 flows into the discharge space 106. The drug solution that flows into the discharge space 106 is discharged to the blood purifier from the downstream path in the downstream tube 32.

[0077] In the liquid delivery space 105, a first liquid delivery space 107 and a second liquid delivery space 108 are alternately formed, constituting a closed space, by the drive of the pump unit 110. Since a certain amount of liquid chemical is accepted in the first liquid delivery space 107 and the second liquid delivery space 108, the amount of liquid chemical flowing from the liquid delivery space 105 to the discharge space 106 is constant. As a result, a constant amount of liquid chemical can be supplied from the liquid delivery unit 50.

[0078] Next, the connection structure between the fluid delivery unit 50 and the drive unit 60 will be described. Figure 5 is a perspective view showing the connection structure between the rotor's rotating shaft and the drive unit's gear shaft in a medical pump. In Figure 5, the connection structure between the first rotating shaft 120 and the first gear shaft 65 is illustrated as an example.

[0079] As shown in Figures 3 and 5, the first rotating shaft 120 and the second rotating shaft 130 and the drive unit 60 are configured to be able to move toward and away from each other. In this embodiment, the first rotating shaft 120 is configured to be able to move toward and away from the first gear shaft 65, and the second rotating shaft 130 is configured to be able to move toward and away from the second gear shaft 66. As a result, the fluid supply unit 50 is provided to be detachably attached to the drive unit 60.

[0080] Specifically, the medical pump 20 in this embodiment has a connecting portion 160. The connecting portion 160 fixes the rotational positional relationship between the first rotating shaft 120 and the first gear shaft 65, while allowing the first rotating shaft 120 to move toward and away from the first gear shaft 65 in the first direction (Y direction). As a result, the fluid delivery unit 50 can be attached to and detached from the drive unit 60 in the first direction (Y direction).

[0081] As shown in Figure 5, the connecting portion 160 has a first key portion 161 and a first groove portion 162. The first key portion 161 is provided at the axial (Y-direction) end of the first rotating shaft 120. The first key portion 161 protrudes toward the first gear shaft 65. The first key portion 161 has a flat plate shape.

[0082] The first groove 162 is provided at the axial (Y-direction) end of the first gear shaft 65. The first groove 162 is recessed in the axial (Y-direction) direction so that the first key portion 161 can engage with it.

[0083] When the fluid delivery unit 50 is attached to the drive unit 60, the first key portion 161 and the first groove portion 162 engage. This fixes the positional relationship of the rotational angles between the first rotating shaft 120 and the first gear shaft 65. As a result, when the fluid delivery unit 50 is attached to the drive unit 60, the first rotating shaft 120 can rotate while fixing the positional relationship of the rotational directions of the first rotating shaft 120 and the first gear shaft 65, and the fluid delivery unit 50 can also be removed from the drive unit 60.

[0084] In the drive unit 60 after the fluid delivery unit 50 has been removed, the first groove 162 is positioned to its initial position before another fluid delivery unit 50 is installed. In this embodiment, the initial position is, for example, when the first groove 162 is aligned in the X direction. This allows the fluid delivery unit 50 to be mounted on the drive unit 60 at the same rotational position.

[0085] Furthermore, the same connection structure as that of the connection part 160 can be used for the connection between the second rotating shaft 130 and the second gear shaft 66. Also, the connection part 160 is not limited to the configuration of the first key part 161 and the first groove part 162, as long as the first rotating shaft 120 can rotate while fixing the rotational positional relationship between the first rotating shaft 120 and the first gear shaft 65, and the fluid supply part 50 can be removed from the drive part 60. For example, the connection part 160 may employ a clutch mechanism.

[0086] Let's assume a scenario where the fluid delivery unit 50 and the drive unit 60 are not configured to be detachable. When changing the medication, there is a possibility that the previously used medication may remain in the fluid delivery unit 50, causing the new medication to mix with the old one. On the other hand, in the medical pump 20 of this embodiment, since the fluid delivery unit 50 is detachably provided from the drive unit 60, a new fluid delivery unit 50 can always be replaced in the infusion device 1 when changing the medication. As a result, a clean medication can be supplied.

[0087] Figure 6 is a perspective view showing the connection between the fluid delivery unit and the drive unit in a medical pump.

[0088] As shown in Figure 6, the connecting portion 160 has a second key portion 165 and a second groove portion 166. The second key portion 165 is provided at the axial (Y-direction) end of the second rotating shaft 130. The second key portion 165 protrudes toward the second gear shaft 66. The second key portion 165 has a flat plate shape.

[0089] The second groove 166 is provided at the axial (Y-direction) end of the second gear shaft 66. The second groove 166 is recessed in the axial (Y-direction) direction so that the second key portion 165 can engage with it.

[0090] The medical pump 20 in this embodiment further includes a locking mechanism 170. The locking mechanism 170 is configured to allow the fluid delivery unit 50 to be attached to the drive unit 60 only when the corresponding protrusions 143 and recesses 153 are engaged.

[0091] Specifically, the locking mechanism 170 is comprised of the engagement of the convex portion 143 and the concave portion 153, the connection portion 160, and the control of the rotational positions of the first gear shaft 65 and the second gear shaft 66.

[0092] When the convex portion 143 and the concave portion 153 are engaged, the longitudinal direction of the keys in the first key portion 161 and the second key portion 165 are aligned with the X direction. The first key portion 161 engages with the first groove portion 162 and the second key portion 165 engages with the second groove portion 166 only when the longitudinal direction of the grooves in the first groove portion 162 and the second groove portion 166 are aligned with the X direction. As a result, the fluid supply unit 50 can be attached to the drive unit 60 only when the corresponding convex portion 143 and concave portion 153 are engaged.

[0093] The operation of the locking mechanism 170 is as follows: First, after the liquid supply from the liquid supply unit 50 is completed, the liquid supply unit 50 is removed from the drive unit 60. At this time, since the first rotating shaft 120 and the second rotating shaft 130 can be rotated at any angle to remove the liquid supply unit 50 from the drive unit 60, the rotation of the rotor caused by the supply of the chemical solution is suppressed when the liquid supply unit 50 is removed from the drive unit 60.

[0094] Next, the rotational positions of the first gear shaft 65 and the second gear shaft 66 are adjusted so that the longitudinal direction of the grooves in the first groove 162 and the second groove 166 is aligned with the X direction. This adjustment of rotational position is performed by the control unit 80. Next, a new fluid supply unit 50 is prepared so that the convex portion 143 and the concave portion 153 are engaged, and the longitudinal direction of the keys in the first key portion 161 and the second key portion 165 is aligned with the X direction. The new fluid supply unit 50 is mounted on the drive unit 60. This ensures that the fluid supply unit 50 is mounted on the drive unit 60 only when the corresponding convex portion 143 and concave portion 153 are engaged.

[0095] When transporting only the fluid delivery unit 50 of the medical pump 20, it is desirable that the convex portion 143 and the concave portion 153 be interlocked during transport. This ensures that the convex portion 143 and the concave portion 153 are securely interlocked, making it easier to attach the fluid delivery unit 50 to the drive unit 60.

[0096] Next, the sliding characteristics of the internal structure of the fluid delivery unit 50 will be described. Figure 7 is a top view showing the configuration of the rotor in a medical pump. For convenience, in Figure 7, the first rotor 140 and the second rotor 150 are shown spaced apart.

[0097] As shown in Figure 7, the first rotor 140 has a first seal portion 145. The first seal portion 145 protrudes in a first direction (Y direction) at the first outer peripheral edge portion 146 of the first rotor 140. The first outer peripheral edge portion 146 is the outer peripheral edge portion in the circumferential direction in the first direction (Y direction). The first seal portion 145 is slidable against the inner surface 100A (see Figure 3) of the housing 100.

[0098] The second rotor 150 has a second seal portion 155. The second seal portion 155 protrudes in a first direction (Y direction) at the second outer peripheral edge portion 156 of the second rotor 150. The second outer peripheral edge portion 156 is the outer peripheral edge portion in the circumferential direction in the first direction (Y direction). The second seal portion 155 is slidable with the inner surface 100A (see Figure 3) of the housing 100.

[0099] The provision of the first seal portion 145 and the second seal portion 155 seals and partitions the suction space 104, the liquid delivery space 105, and the discharge space 106 within the internal space 101 of the housing 100. Furthermore, compared to the case where the first rotor 140 and the second rotor 150 are in full contact with the inner surface 100A of the housing 100, the sliding resistance is reduced, allowing the pump unit 110 to be driven more efficiently.

[0100] The protrusion amounts of the first seal portion 145 and the second seal portion 155 are preferably larger than the internal space 101 so that they are pressed against the inner surface 100A of the housing 100 within the range of elastic deformation of the first seal portion 145 and the second seal portion 155. This makes it easier to ensure sealing performance in the internal space 101 of the housing 100 while reducing the sliding resistance of the first rotor 140 and the second rotor 150 during rotation.

[0101] Next, we will explain how pulsation is reduced when the medical pump 20 delivers the drug solution. Figure 8 is a partial cross-sectional view showing the state just before the convex portion of the first rotor and the concave portion of the second rotor engage.

[0102] As shown in Figure 8, a retention area 109 is formed inside the recess 153 of the second rotor 150 where the chemical solution accumulates. As the first rotor 140 and the second rotor 150 rotate synchronously, the protrusion 143 enters the retention area 109 of the recess 153, and the chemical solution in the retention area 109 flows out of the recess 153 into the second liquid delivery space 108 and the discharge space 106.

[0103] Figure 9 is a schematic diagram showing the relationship between the rotational positions of the convex portion of the first rotor and the concave portion of the second rotor and each term.

[0104] Here, as shown in Figures 8 and 9, the "start of entry" of the convex portion 143 into the recess 153 is defined as the point when the convex portion 143 begins to enter the virtual arc of the second outer surface 152 of the recess 153 (the dotted line portion in Figure 8). The "end of entry" of the convex portion 143 into the recess 153 is defined as the point when the convex portion 143 has entered the recess 153 and the chemical solution inside the recess 153 has flowed out.

[0105] In other words, as shown in Figure 9, the "start of entry" is the point in time when the first rotor 140 is at rotational position R1. The "end of entry" is the point in time when the first rotor 140 is at rotational position R2.

[0106] Furthermore, the range of rotational positions during one rotation of the first rotor 140 is referred to as a term. The period from the "start of entry" of the convex portion 143 into the concave portion 153 to the "end of entry" when the corresponding convex portion 143 and concave portion 153 engage (the period during which the first rotor 140 is between rotational position R1 and rotational position R2) is defined as the first term T1. Of all terms during one rotation of the first rotor 140, all terms other than the first term T1 are defined as the second term T2.

[0107] If the rotational speeds of the first rotor 140 and the second rotor 150 are the same for the entire duration of one rotation of the first rotor 140, then the chemical solution that has entered the retention section 109 will be pushed out of the retention section 109 by the protrusion 143 and flow into the discharge space 106. As a result, the amount of chemical solution discharged in the discharge space 106 may increase when added to the flow rate of the chemical solution discharged from the liquid supply space 105. In other words, the amount of chemical solution discharged temporarily increases when the protrusion 143 and the recess 153 are engaged. This causes the amount of chemical solution discharged to increase or decrease depending on whether the protrusion 143 and the recess 153 are engaged or not, and a pulsating flow of the chemical solution discharged from the liquid supply section 50 may occur.

[0108] In this embodiment, the first rotational speed of the first rotor 140 and the second rotor 150 in the first term T1 is lower than the second rotational speed of the first rotor 140 and the second rotor 150 in the second term T2.

[0109] By adjusting the rotational speed as described above, when the convex portion 143 begins to enter the concave portion 153 and the chemical solution inside the retention portion 109 begins to flow out, the rotational speed of the first rotor 140 and the second rotor 150 is reduced, thereby decreasing the flow rate of the chemical solution flowing from the liquid delivery space 105 to the discharge space 106. As a result, the total flow rate of the chemical solution flowing out of the retention portion 109 and the chemical solution being delivered from the liquid delivery space 105 in the term in which the convex portion 143 and the concave portion 153 are engaged can be made approximately the same as the flow rate of the chemical solution being delivered from the liquid delivery space 105 in the term in which the convex portion 143 and the concave portion 153 are not engaged.

[0110] The above adjustment of rotational speed is preferably applied when the rotational speeds of the first rotor 140 and the second rotor 150 are relatively low. This is because when the rotational speed is relatively low, the proportion of time during which pulsation occurs per unit of time increases, thus greatly suppressing pulsation. However, when the rotational speed is relatively high and the proportion of time during which pulsation occurs per unit of time decreases, the rotor may rotate at a constant speed without any adjustment of the rotational speed.

[0111] Next, the operation of the infusion device during priming will be described. The control unit 80 starts the priming process, detects the drug solution with the bubble sensor 40, controls the rotation speed of the first rotor 140, and stops the priming process when the drug solution fills the downstream path in the downstream tube 32 and the bubble sensor 40 detects that there are no more bubbles in the downstream path. This ensures that the priming process is performed accurately regardless of the amount of drug solution in the upstream path of the upstream tube 31.

[0112] Furthermore, an overflow cap may be attached to the end of the downstream tube 32 opposite to the side connected to the medical pump 20, and after the drug solution has passed the bubble sensor 40, a larger amount of drug solution than the predetermined amount may be delivered. This ensures that even if bubbles are mixed in the drug solution, the inside of the downstream path can be filled with the drug solution.

[0113] Next, we will explain the operation of the infusion device when the pathway through which the drug solution flows is blocked. The control unit 80 can detect blockages in the upstream and downstream pathways by measuring the drive torque in the drive unit 60.

[0114] Specifically, if a blockage occurs in the downstream path, the liquid cannot be delivered to the downstream path, causing the pressure inside the liquid delivery space 105 and the discharge space 106 to rise. When the pressure inside the liquid delivery space 105 and the discharge space 106 rises, the driving torque in the drive unit 60 increases. This increase in driving torque is measured to detect that a blockage has occurred in the downstream path.

[0115] Furthermore, if an obstruction occurs in the upstream path, the drug solution will not be supplied from the suction space 104, causing a decrease in the pressure inside the suction space 104 and the liquid delivery space 105. This decrease in pressure inside the suction space 104 and the liquid delivery space 105 creates resistance to the rotation of the pump unit 110, causing the drive torque in the drive unit 60 to increase. This increase in drive torque is measured to detect that an obstruction has occurred in the downstream path.

[0116] If the infusion device 1 detects an obstruction in the upstream or downstream path in the control unit 80, it will, for example, display on the display unit of the device body 10 that an obstruction has occurred.

[0117] Furthermore, the method for detecting blockages in the control unit 80 is not limited to measuring the drive torque in the drive unit 60. The method for detecting blockages in the control unit 80 may be to measure the increase in drive torque during normal operation, using the drive torque during priming as a reference. This eliminates the influence of variations in sliding resistance between the components of the fluid delivery unit on blockage detection, and allows for highly accurate measurement of blockages.

[0118] Furthermore, the blockage detection method in the control unit 80 may be a method of measuring the drive torque from the current value of the motor unit 70. This makes it possible to measure the drive torque without providing a separate sensor for measuring the drive torque.

[0119] Furthermore, the method for detecting blockage in the control unit 80 may be a method of measuring the drive torque using a magnetostrictive torque sensor. This allows for non-contact measurement of the drive torque.

[0120] Next, we will explain the suppression of free flow. Free flow refers to a state in which the first rotor 140 and the second rotor 150 of the fluid delivery unit 50 rotate due to the weight of the drug solution itself, etc., when the first rotor 140 and the second rotor 150 are not connected to the drive unit 60 and can rotate freely, resulting in the drug solution being administered to the patient unintentionally.

[0121] In the liquid delivery unit 50, the static friction coefficient between the housing 100 and each of the first rotor 140 and the second rotor 150 is set to a range in which the first rotor 140 and the second rotor 150 do not rotate due to the pressure difference between the heads of the chemical solution flowing in the upstream and downstream paths. As a result, even when the first rotor 140 and the second rotor 150 are in a state where they can rotate freely without being connected to the drive unit 60, their rotation is suppressed. Consequently, free flow can be suppressed when the liquid delivery unit 50 is removed from the drive unit 60.

[0122] Furthermore, when the fluid delivery unit 50 is attached to the drive unit 60, the combined force of the rotational holding force of the drive unit 60 and the resistance force due to the static friction coefficients between the components of the fluid delivery unit 50 may be set to a range in which the first rotor 140 and the second rotor 150 do not rotate due to the pressure difference of the liquid delivery. In this case, the medical pump has a function that replaces the tube clamping function when using a tube pump.

[0123] The following describes a medical pump and infusion device according to a first modification of one embodiment of the present invention. Since the material of the components of the fluid delivery section of the medical pump and infusion device according to the first modification differs from that of the medical pump 20 and infusion device 1 according to one embodiment of the present invention, the same configurations as those of the medical pump 20 and infusion device 1 according to one embodiment of the present invention will not be repeated in the description.

[0124] In the medical pump of the infusion device according to the first modified example, at least one of the housing, the first rotor, and the second rotor is made of a resin material including polyethylene resin. In this modified example, the housing, the first rotor, and the second rotor are all made of a resin material including polyethylene resin.

[0125] A resin material containing polyethylene resin is, for example, a resin composition comprising at least a polyethylene resin, silicone-grafted polyethylene, and silicone oil, wherein the silicone-grafted polyethylene is obtained by grafting polyethylene with at least one selected from the group consisting of polydimethylsiloxane, polymethylphenylsiloxane, and polydiphenylsiloxane.

[0126] Specifically, the resin material containing polyethylene resin may be, for example, Lubmer® or Exfora® manufactured by Mitsui Chemicals.

[0127] The following describes a medical pump and infusion device according to a second modification of one embodiment of the present invention. The medical pump and infusion device according to the second modification differ from the medical pump 20 and infusion device 1 according to one embodiment of the present invention in that the adjustment of the rotational speed of the first rotor 140 and the second rotor 150 is different. Therefore, the same configuration as the medical pump 20 and infusion device 1 according to one embodiment of the present invention will not be repeated in the description.

[0128] Figure 10 is a schematic diagram showing the relationship between the rotational positions of the convex portion of the first rotor and the concave portion of the second rotor and each term, according to a second modified example of one embodiment of the present invention.

[0129] As shown in Figure 10, the "end of exit" point of the convex portion 143 from the recess 153 is defined as the point when the convex portion 143 separates from the virtual arc of the second outer peripheral surface 152 (the dotted line portion in Figure 8). In other words, the "end of exit" point is the point when the first rotor 140 is at rotational position R3.

[0130] Furthermore, the period from the "start of entry" of the convex portion 143 into the recess 153 to the "end of exit" when the corresponding convex portion 143 and recess 153 engage (the period during which the first rotor 140 is between rotational position R1 and rotational position R3) is defined as the third term T3. Of all the terms during which the first rotor 140 completes one rotation, all terms other than the third term T3 are defined as the fourth term T4.

[0131] In this embodiment, the first rotational speed of the first rotor 140 and the second rotor 150 in the third term T3 is lower than the second rotational speed of the first rotor 140 and the second rotor 150 in the fourth term T4.

[0132] By adjusting the rotation speed as described above, similar to the case of a medical pump in one embodiment, the total flow rate of the drug solution flowing out of the stagnant section 109 and the drug solution delivered from the delivery space 105 in the terms where the convex portion 143 and the concave portion 153 are engaged can be made approximately the same as the flow rate of the drug solution delivered from the delivery space 105 in the terms where the convex portion 143 and the concave portion 153 are not engaged.

[0133] Furthermore, when the protrusion 143 exits the recess 153, the drug solution flows into the recess 153, increasing the amount of drug solution inhaled in the inhalation space 104, which can cause pulsating flow of the drug solution upstream of the medical pump 20. However, by slowing down the rotor rotation during the period from when the protrusion 143 enters the recess 153 until it exits, the flow rate of the drug solution can be adjusted, making the amount of drug solution inhaled upstream of the pump uniform throughout the entire period. This makes it possible to suppress fluctuations in the liquid level of the drug solution in the trap chamber, for example, when a trap chamber is provided upstream of the medical pump 20.

[0134] The following describes a medical pump and infusion device according to a third modification of one embodiment of the present invention. Since the connection configuration between the fluid delivery unit and the drive unit of the medical pump 20 and infusion device 1 according to one embodiment of the present invention differs from that of the medical pump 20 and infusion device 1 according to one embodiment of the present invention, the same configuration as that of the medical pump 20 and infusion device 1 according to one embodiment of the present invention will not be repeated in the description.

[0135] Figure 11 is a partial cross-sectional view showing the configuration of a medical pump according to a third modified example of one embodiment of the present invention.

[0136] As shown in Figure 11, a medical pump 20C according to a third modified example of one embodiment of the present invention comprises a fluid delivery unit 50C and a drive unit 60C.

[0137] The fluid delivery unit 50C includes a housing 100C and a pump unit 110C. The pump unit 110C has a first rotor 140C, a second rotor 150C, a first bearing unit 125C, and a second bearing unit 135C. The first bearing unit 125C is recessed in the Y direction from the side surface of the first rotor 140C. The second bearing unit 135C is recessed in the Y direction from the side surface of the second rotor 150C. The pump unit 110C does not have a rotating shaft. Furthermore, the housing 100C does not have a space for housing such a rotating shaft.

[0138] The drive unit 60C has a first gear shaft 65C and a second gear shaft 66C. The first gear shaft 65C is inserted through the first bearing portion 125C. The second gear shaft 66C is inserted through the second bearing portion 135C.

[0139] The first bearing portion 125C and the first gear shaft 65C are configured to be able to move toward and away from each other by a connecting portion 160C. The second bearing portion 135C and the second gear shaft 66C are configured to be able to move toward and away from each other by a connecting portion 160C. The connecting portion 160C is composed of a key portion and a groove portion, similar to the connecting portion 160 in one embodiment.

[0140] In this modified example, the configuration of the fluid delivery unit 50C can be simplified by consolidating the shafts that rotate the first rotor 140C and the second rotor 150C into the drive unit 60C.

[0141] In a medical pump 20 according to one embodiment of the present invention, the first rotor 140 and the second rotor 150 rotate synchronously such that the convex portion 143 and the concave portion 153 of the fluid delivery unit 50 interlock. This configuration eliminates the change in the diameter of the tube over time, as is the case with a tube pump, allowing for the supply of a constant amount of medication. Furthermore, since the fluid delivery unit 50 is detachably mounted from the drive unit 60 by releasing the connection between the first rotating shaft 120 and the second rotating shaft 130 of the fluid delivery unit 50 and the drive unit 60, the fluid delivery unit 50 can be removed from the infusion device 1 and replaced when changing the medication flowing through the fluid delivery unit 50. This ensures that no previous medication remains in the fluid delivery unit 50, allowing for the supply of medication in a clean state. As a result, the medical pump 20 can supply a constant amount of medication in a clean state.

[0142] In a medical pump 20 according to one embodiment of the present invention, a locking mechanism 170 is provided that allows the fluid delivery unit 50 to be attached to the drive unit 60 only when the corresponding protrusions 143 and recesses 153 are engaged, thereby ensuring that the protrusions 143 and recesses 153 are reliably engaged when replacing the fluid delivery unit 50.

[0143] In a medical pump 20 according to one embodiment of the present invention, by providing a first seal portion 145 on the first rotor 140 and a second seal portion 155 on the second rotor 150, it is possible to ensure sealing performance while reducing sliding resistance compared to the case in which the internal space 101 is sealed by sliding the entire surfaces of the first rotor 140 and the second rotor 150 within the housing 100.

[0144] In a medical pump 20 according to one embodiment of the present invention, at least one of the housing 100, the first rotor 140, and the second rotor 150 is made of a resin material including polypropylene resin, thereby improving the sliding properties, chemical resistance, and wear resistance of the liquid delivery section 50.

[0145] In a medical pump according to a first modified embodiment of the present invention, the sliding properties, chemical resistance, and wear resistance of the liquid delivery section can be improved by having at least one of the housing, first rotor, and second rotor made of a resin material including polyethylene resin.

[0146] In one embodiment of the present invention, an infusion device 1 is provided with a bubble sensor 40. During priming, the bubble sensor 40 detects the drug solution, and the rotation speed of the first rotor 140 is controlled. Additionally, the priming process can be automatically stopped after confirming that the downstream path of the downstream tube 32 is filled with the drug solution. This allows for accurate priming regardless of the priming process status upstream of the fluid delivery unit 50.

[0147] In one embodiment of the present invention, the infusion device 1 can detect blockages in the upstream and downstream pathways by measuring the drive torque of the drive unit 60. In the case of an infusion device using a tube pump, even if blockage occurs in the drug solution pathway, the tube pump simply rotates without changing its drive torque, and the blockage of the drug solution pathway cannot be detected by the drive torque of the tube pump. However, in the infusion device 1, blockages in the upstream and downstream pathways can be detected by the drive torque of the drive unit 60.

[0148] In one embodiment of the present invention, the static friction coefficient between the housing 100 and each of the first rotor 140 and the second rotor 150 is set to a range in which the first rotor 140 and the second rotor 150 do not rotate due to the pressure difference of the drug solution, thereby suppressing free flow when the fluid delivery unit 50 is removed from the drive unit 60.

[0149] In a medical pump 20 according to one embodiment of the present invention, the first rotational speed of the first rotor 140 and the second rotor 150 in the first term T1, from the time the convex portion 143 begins to enter the recess 153 when the corresponding convex portion 143 and recess 153 engage, to the time the convex portion 143 ends its entry, is set lower than the second rotational speed of the first rotor 140 and the second rotor 150 in the second term T2 other than the first term T1. As a result, when the convex portion 143 engages with the recess 153, the drug solution that has accumulated in the recess 153 flows out, increasing the flow rate. By slowing down the rotational speed of the first rotor 140 and the second rotor 150 to adjust the flow rate of the drug solution, the pulsating flow of the drug solution can be reduced.

[0150] In a medical pump 20 according to a second modification of one embodiment of the present invention, the first rotational speed of the first rotor 140 and the second rotor 150 in the third term T3, from the time the convex portion 143 begins to enter the recess 153 when the corresponding convex portion 143 and recess 153 engage, to the time when it finishes to exit, is lower than the second rotational speed of the first rotor 140 and the second rotor 150 in the fourth term T4 other than the third term T3. As a result, when the convex portion 143 engages with the recess 153, the drug solution that has accumulated in the recess 153 flows out, increasing the flow rate. By slowing down the rotational speed of the first rotor 140 and the second rotor 150 to adjust the flow rate of the drug solution, the pulsating flow of the drug solution in the downstream path can be reduced. Furthermore, when the protrusion 143 exits the recess 153, the chemical solution flows into the recess 153, increasing the amount of chemical solution suction and potentially causing pulsation of the chemical solution in the upstream path. However, by slowing down the rotational speed of the first rotor 140 and the second rotor 150 during the third term T3, from the start of the protrusion 143 entering the recess 153 to its exit, the flow rate of the chemical solution can be adjusted, thereby reducing pulsation of the chemical solution in the upstream path. As a result, for example, when a trap chamber is provided in the upstream path, fluctuations in the liquid level of the chemical solution in the trap chamber can be suppressed.

[0151] In one embodiment of the present invention, the infusion device 1 is equipped with a medical pump 20 that can reduce the pulsation of the drug solution. This makes it possible to suppress the decrease in infusion accuracy caused by pulsation of the tube when the drug solution's flow path is made of tubes. Furthermore, it is possible to suppress tube deterioration, such as changes in the internal cross-sectional area of ​​the tube over time, which occurs in tube pumps.

[0152] In the above description, we have explained the case in which a medical pump is applied to a blood purification device, but the medical pump according to one embodiment of the present invention can also be applied to other infusion devices.

[0153] The embodiments disclosed herein are illustrative in all respects and do not constitute a limiting interpretation. Therefore, the technical scope of this disclosure is not limited to the embodiments described above. Furthermore, all modifications within the meaning and scope of equivalence to the claims are included. In the description of the embodiments above, combinatorial configurations may be combined with each other. [Explanation of Symbols]

[0154] 1 Infusion device, 10 Device body, 20, 20C Medical pump, 30 Tubing, 31 Upstream tubing, 32 Downstream tubing, 40 Bubble sensor, 50, 50C Fluid delivery unit, 60, 60C Drive unit, 61 Gear housing, 62 Enclosure space, 63 First gear, 64 Second gear, 65, 65C First gear shaft, 66, 66C Second gear shaft, 70 Motor unit, 80 Control unit, 85 Connection detection sensor, 100, 100C Housing, 100A Inner surface, 101 Internal space, 102 First inner surface, 103 Second inner surface, 104 Intake space, 105 Fluid delivery space, 106 Discharge space, 107 First fluid delivery space, 108 Second fluid delivery space, 109 Retention space, 110, 110C Pump unit, 120 121 First rotation axis, 125C First shaft center, 130 Second rotation axis, 131 Second shaft center, 135C Second bearing part, 140, 140C First rotor, 141 First body part, 142 First outer surface, 143 Protrusion, 145 First seal part, 146 First outer edge part, 150, 150C Second rotor, 151 Second body part, 152 Second outer surface, 153 Recess, 155 Second seal part, 156 Second outer edge part, 160, 160C Connecting part, 161 First key part, 162 First groove part, 165 Second key part, 166 Second groove part, 170 Locking mechanism, R1, R2, R3 Rotation position, T1 First term, T2 Second term, T3 Third term, T4 Fourth term.

Claims

1. A liquid delivery unit that delivers the drug solution, The system includes a drive unit for driving the liquid delivery unit, The aforementioned liquid delivery unit is The casing and The housing includes a pump unit located inside the housing, The aforementioned pump section is A first rotating shaft connected to the drive unit and driven by the drive unit, and extending in the first direction, A second rotating shaft is connected to the drive unit, driven by the drive unit, and extends in parallel with respect to the first rotating shaft in the first direction, A first rotor that is rotatable in the circumferential direction of the first rotating shaft in conjunction with the rotation of the first rotating shaft, It has a second rotor that is rotatable in the circumferential direction of the second rotating shaft in conjunction with the rotation of the second rotating shaft, The first rotor has a plurality of protrusions on a part of its first outer surface that project radially in the direction of the first rotor. The second rotor is provided with a plurality of recesses formed by a portion of the second outer surface of the second rotor being recessed in the radial direction of the second rotor. The first rotor and the second rotor are synchronously rotatable such that corresponding protrusions and recesses among the plurality of protrusions and the plurality of recesses interlock. A liquid supply space is provided between the inner circumferential surface and the first outer circumferential surface of the housing. Each of the aforementioned multiple protrusions slides against the inner circumferential surface when the first rotor rotates. As the first rotor rotates, the liquid chemical present in the liquid delivery space is delivered by the protrusions in the liquid delivery space among the plurality of protrusions. A medical pump wherein the first rotational speed of the first rotor and the second rotor in a first term, from the time the protrusion begins to enter the recess when the corresponding protrusion and recess engage, to the time the protrusion ends, is lower than the second rotational speed of the first rotor and the second rotor in a second term other than the first term.

2. A liquid delivery unit that delivers the drug solution, The system includes a drive unit for driving the liquid delivery unit, The aforementioned liquid delivery unit is The casing and The housing includes a pump unit located inside the housing, The aforementioned pump section is A first rotating shaft connected to the drive unit and driven by the drive unit, and extending in the first direction, A second rotating shaft is connected to the drive unit, driven by the drive unit, and extends in parallel with respect to the first rotating shaft in the first direction, A first rotor that is rotatable in the circumferential direction of the first rotating shaft in conjunction with the rotation of the first rotating shaft, It has a second rotor that is rotatable in the circumferential direction of the second rotating shaft in conjunction with the rotation of the second rotating shaft, The first rotor has a plurality of protrusions on a part of its first outer surface that project radially in the direction of the first rotor. The second rotor is provided with a plurality of recesses formed by a portion of the second outer surface of the second rotor being recessed in the radial direction of the second rotor. The first rotor and the second rotor are synchronously rotatable such that corresponding protrusions and recesses among the plurality of protrusions and the plurality of recesses interlock. A liquid supply space is provided between the inner circumferential surface and the first outer circumferential surface of the housing. Each of the aforementioned multiple protrusions slides against the inner circumferential surface when the first rotor rotates. As the first rotor rotates, the liquid chemical present in the liquid delivery space is delivered by the protrusions in the liquid delivery space among the plurality of protrusions. A medical pump wherein the first rotational speed of the first rotor and the second rotor in a third term, from the time the corresponding protrusion begins to enter the recess to the time it ends to exit, is lower than the second rotational speed of the first rotor and the second rotor in a fourth term other than the third term.

3. A medical pump according to claim 1 or claim 2, An infusion device comprising a downstream tube provided downstream of the medical pump and constituting a downstream path for the drug solution, and an upstream tube provided upstream of the medical pump and constituting an upstream path for the drug solution.

Images