Precision pumps with automatic valve switching and low-volume pumps with side-ported cannula for low-tolerance stackup

Abstract

A pump for pumping small volumes of medical fluid is provided. The pump has a manifold chamber with an inlet port and an outlet port. Within the manifold chamber, a cannula having input and output holes oriented relative to the inlet and outlet ports is rotated within the manifold chamber and axially translated in a reciprocating manner. The input opening of the cannula overlaps with the inlet port as the manifold chamber volume increases, drawing fluid into the manifold chamber from the input port. The output opening of the cannula chamber overlaps with the output port as the manifold chamber volume decreases, forcing fluid out of the manifold chamber and into the outlet port. The cannula may be formed from metal needle stock.

Description

[Technical Field]

[0001] The present invention relates generally to a compact, accurate, reliable, and low-cost pump suitable for subcutaneous delivery of liquid medications. More specifically, embodiments of the present invention relate to a pump having a side port cannula that reciprocates during rotation following a cam surface to pump fluid by displacement. The medication delivered can be insulin for diabetic patients. [Background technology]

[0002] Diabetes is a group of diseases characterized by elevated blood glucose levels due to impaired insulin secretion, insulin action, or both. Diabetes affects 23.6 million Americans, or 8% of the population. The overall prevalence of diabetes has increased 13.5% since 2005-2007. Diabetes can lead to serious health complications and premature death, but there are well-known products available for people with diabetes to help control the disease and reduce the risk of complications.

[0003] Treatment for people with diabetes includes specialized diets, oral medications, and / or insulin therapy. The primary goal of diabetes treatment is to control a patient's blood glucose (sugar) levels to improve the chances of living a complication-free life. However, achieving good diabetes management while balancing other life demands and circumstances is not always easy.

[0004] Currently, there are two main modes of daily insulin therapy for the treatment of type 1 diabetes. The first mode is syringes or insulin pens, which require a needle prick for each injection and are typically administered three to four times a day. They are easy to use and relatively inexpensive. Another widely adopted and effective method for managing diabetes is the use of insulin pumps. By continuously injecting insulin, insulin pumps help users maintain blood glucose levels within a target range based on their individual needs. Using an insulin pump allows users to match their insulin therapy to their lifestyle, rather than matching their lifestyle to how insulin injections work.

[0005] Conventional insulin pumps can deliver rapid- or short-acting insulin 24 hours a day through a catheter placed under the skin. Insulin doses are typically administered at a basal rate and in bolus doses. Basal insulin is delivered continuously over 24 hours to maintain the user's blood glucose levels in a consistent range between meals and overnight. Insulin pumps may also allow the basal rate of insulin to be programmed to vary depending on the time of day and night. Bolus doses are typically administered when the user eats a meal and generally provide a single additional insulin injection to balance the carbohydrates consumed. Some conventional insulin pumps allow the user to program the bolus dose based on the amount or type of meal consumed. Conventional insulin pumps also allow the user to take a corrective or replacement bolus of insulin to compensate for low blood glucose levels when calculating a meal bolus.

[0006] Traditional insulin pumps offer many advantages over other methods of diabetes treatment. Because insulin pumps deliver insulin over time rather than as a single injection, they typically result in less fluctuation within the blood glucose range recommended by the American Diabetes Association. Traditional insulin pumps also reduce the number of needle sticks patients must endure, making diabetes management easier and more effective for users and therefore significantly improving their quality of life.

[0007] A major drawback of existing insulin pumps is that, despite their portability, they contain multiple components and are heavy and cumbersome to use. They are also typically more expensive than other treatment methods. From a lifestyle perspective, traditional pumps with associated tubing and infusion sets can be inconvenient and a nuisance for users.

[0008] Unlike traditional infusion pumps, patch pumps are integrated devices that combine most or all of the fluidic components, including the fluid reservoir, pumping mechanism, and mechanism for automatically inserting a cannula, into a single housing that adhesively attaches to the infusion site on the patient's skin and does not require the use of a separate infusion or tubing set. Some patch pumps communicate wirelessly with a separate controller device (such as one device sold by Insulet under the brand name OmniPod™), while others are completely self-contained. Such devices are replaced frequently, such as every three days, when the insulin supply is depleted.

[0009] Because patch pumps are designed to be self-contained units worn by diabetic patients, they are preferably as small as possible so as not to interfere with the user's activities. To minimize discomfort to the user, it is preferable to minimize the overall dimensions of the patch pump. However, minimizing the overall dimensions of the patch pump requires that the sizes of its component parts be minimized as much as possible.

[0010] Therefore, there is a need in the art for an accurate, compact, and cost-effective fluid pump that can be provided as part of a disposable system such as a patch pump.

[0011] An objective of exemplary embodiments of the present invention is to provide an accurate, compact and cost-effective pump for wearable medical devices so that more diabetic patients can benefit from the advantages these devices offer. Summary of the Invention

[0012] According to one embodiment of the present invention, a pump for pumping a liquid is provided, the pump comprising a manifold chamber having an inlet port and an outlet port. Within the manifold chamber, a cannula having input and output holes oriented relative to the inlet and outlet ports is rotated within the manifold chamber and axially translated in a reciprocating manner. The input opening of the cannula overlaps with the inlet port as the manifold chamber volume increases to draw fluid into the manifold chamber from the input port. The output opening of the cannula chamber overlaps with the output port as the manifold chamber volume decreases to force fluid out of the manifold chamber to the outlet port.

[0013] An advantage of a pump according to one embodiment of the present invention is that it can pump very small and precise amounts of liquid medication with each rotation of the side port cannula. The cannula is formed from very precise gauge needle stock and can be reciprocated a very precise distance. This allows for very precise injection of small liquid doses, reduces tolerances, and reduces material contact with the pharmaceutical liquid. [Brief explanation of the drawings]

[0014] The above and other illustrative objects, features, and advantages of the present invention will become more apparent from the following description of specific illustrative embodiments thereof when taken in conjunction with the accompanying drawings. [Figure 1]FIG. 1 is an isometric view of a pump in accordance with an exemplary embodiment of the present invention. [Figure 2] FIG. 2 is an exploded view of a pump according to an exemplary embodiment of the present invention. [Figure 3] FIG. 3 is a side cross-sectional view of a pump in accordance with an exemplary embodiment of the present invention. [Figure 4] FIG. 4 is a top cross-sectional view according to an exemplary embodiment of the present invention. [Figure 5] FIG. 5 is an isometric view of a cam chamber cap in accordance with an exemplary embodiment of the present invention. [Figure 6] FIG. 6 is an isometric view of a cam chamber housing according to an exemplary embodiment of the present invention. [Figure 7] FIG. 7 is a side view of a cannula assembly in accordance with an exemplary embodiment of the present invention. [Figure 8] FIG. 8 is a bottom view of a cannula assembly in accordance with an exemplary embodiment of the present invention. [Figure 9] FIG. 9 is a diagram illustrating various operating states of a micropump according to an exemplary embodiment of the present invention. [Figure 10] FIG. 10 is a diagram illustrating various operating states of a micropump in accordance with an exemplary embodiment of the present invention. [Figure 11] FIG. 11 is a diagram illustrating various operating states of a micropump according to an exemplary embodiment of the present invention. [Figure 12] FIG. 12 is a diagram illustrating various operating states of a micropump in accordance with an exemplary embodiment of the present invention. [Figure 13] FIG. 13 is a diagram illustrating various operating states of a micropump in accordance with an exemplary embodiment of the present invention. [Figure 14] FIG. 14 is a diagram illustrating various operating states of a micropump in accordance with an exemplary embodiment of the present invention. [Figure 15] 15 is a diagram illustrating various operating states of a micropump in accordance with an exemplary embodiment of the present invention. Throughout the drawings, like reference numbers and like labels will be understood to refer to like elements, features, and structures. DETAILED DESCRIPTION OF THE INVENTION

[0015] The matters exemplified herein are provided to aid in understanding exemplary embodiments of the present invention and are made with reference to the accompanying drawings, and descriptions of well-known functions and structures are omitted for clarity and brevity.

[0016] 1 and 2, the components of a micropump according to an exemplary embodiment of the present invention and how they are assembled will be described in further detail. Micropump 100 includes a main housing 102. Main housing 102 includes a pump chamber 104. A manifold 106 is received in pump chamber 104. Manifold 106 includes a cannula chamber 108 in which a cannula 110 axially rotates and reciprocates. Cannula 110 is secured to a cam body 112. Cam body 112 includes a proximal cam surface 114 and a distal cam surface 116, as well as a motor coupling portion 118. Cam chamber housing 120 and cam chamber cap 122 form a cam chamber 124 in which cam 112 is received. Cam chamber cap 122 also includes an opening 125 through which motor coupling portion 118 extends.

[0017] As shown, main housing 102, cam chamber housing 120, and cam chamber cap 122 include corresponding boss features that prevent relative rotational movement when assembled. Main housing 102 includes bosses 126 and 128 with a space 130 between them. Cam chamber housing 120 includes a boss 132 that is received in opening 130 and abuts bosses 126 and 128. Cam chamber cap 122 includes bosses 134 and 136 that are spaced apart so that boss 132 can be received therebetween and adjacent to one another.

[0018] Further aspects and components of micropump 100 will now be described with reference to FIGS. 3 and 4, which are side and bottom cross-sectional views, respectively, of micropump 100, in accordance with an exemplary embodiment of the present invention. As shown in FIG. 3, manifold 106 includes input port 138 and output port 140. Both ports 138, 140 are connected to manifold chamber 108. Note that cannula 110 fits substantially snugly within manifold chamber 108. Also, note that main housing 102, cam chamber housing 120, and cam chamber cap 122 form a substantially fluid-tight chamber within which cannula 110 can rotate and reciprocate. As can be seen in FIGS. 3 and 4, cannula 110 is mounted on stem 142 of cam 112. Cannula 110 is preferably secured to stem 142 by any known conventional means, including sonic welding, friction engagement, adhesive, or any other suitable securing method. 4, it can be seen that cannula 110 is provided with an input bore 144 and an output bore 146. Cannula input bore 144 is provided in the side wall of cannula 110 at the proximal portion of the cannula. Output bore 146 is provided in the distal portion of cannula 110, on the opposite side of the side wall from input bore 144. Input bore 144 is positioned to overlap input port 138 during a portion of the cam assembly's travel, and output bore 146 is positioned to overlap output bore 140 during a different portion of the cam assembly's 112 rotational travel. The relative rotational and reciprocating movement of cannula 112 within chamber 108 through interaction with cam surfaces 114, 116 of cam 112 within cam chamber housing 120 and cam chamber cap 122 will be described in further detail below.

[0019] 5 is an isometric view of cam chamber cap 122. Cam chamber cap bosses 134 and 136 are shown separated from one another and located on an outer portion of cam chamber cap 122. Cam chamber cap cam surface 148 is located within cam chamber cap 122 to interact with cam surface 114 of cam 112.

[0020] Figure 6 shows an isometric view of cam chamber housing 120. Cam chamber housing boss 132 is provided on an exterior portion of cam chamber housing 120 and fits between cam chamber cap bosses 134 and 136 when micropump 100 is assembled to prevent cam chamber cup 122 from rotating relative to cam chamber housing 120. Also shown in Figure 6 is cam chamber housing cam surface 150, which interacts with cam surface 116 of cam 112, as described in more detail below.

[0021] FIG. 7 shows a side view of cam assembly 112. Cam assembly 112 includes proximal cam service 114 and distal cam service 116. It can be seen that the cam surfaces each have corresponding sloped surfaces that interact with cam chamber cap cam surface 148 and cam chamber housing cam service 150 to translate cannula 110 axially back and forth when cam assembly 112 is rotated by a motor attached to motor coupling 118. As can also be seen in the bottom views of cam assembly 112 shown in FIGS. 7 and 8, cam 112 includes a wide portion 152 and a narrow portion 154.

[0022] 9 through 15, the interaction and movement of each part of micropump 100 will be described. In FIG. 9, cam assembly 112 is in a first position with cam 112 and cannula 110 in their distal-most positions. Thus, in this position, the volume of manifold chamber 108 is between the distal face of manifold chamber 156 and the distal face of stem 158 on the end of stem 142 (see FIG. 3). FIG. 10 shows cam assembly 112 rotated to the beginning of the input portion of its movement. Cam assembly 112 begins to move proximally, as indicated by the distance between end face 156 and end face 158 of cannula 110, shown as reference numeral 158 in FIG. 10, as can be seen due to the interaction of cam surface 116 with cam surface 150, which also causes cannula input bore 144 to begin to overlap input port 138. FIG. 11 shows cam assembly 112 rotated to a position where cannula bore 144 fully overlaps input port 138. Additionally, cam assembly 112 moves further distally, increasing the volume of the pump chamber, as indicated by reference numeral 158. As the pump chamber volume increases, liquid is drawn into manifold chamber 108 by the vacuum. FIG. 12 illustrates cam assembly 112 at the end of the input portion of its movement when the pump chamber volume in manifold chamber 108 is at its maximum, as indicated by reference numeral 158. Additionally, cannula bore 144 stops overlapping input port 138. As shown in FIG. 13, cam assembly 112 rotates further and begins the output portion of its movement. The volume of manifold chamber 108 is still at its maximum, and cannula bore 146 begins to overlap output port 140. At this stage, interaction between cam surface 114 and cam chamber cap cam surface 148 begins to move cannula 110 distally, reducing the volume of manifold chamber 108. 14, the cam assembly has been rotated to a position where the cannula bore 146 is fully aligned with the output port 140. Additionally, the interaction between the cam surface 114 and the cam chamber cap cam surface 148 causes the cam assembly to further translate distally, further reducing the volume of the manifold chamber 108, as indicated at 158.Thus, liquid is forced out of manifold chamber 158 and into output port 140. Figure 15 shows the end of the output portion of the movement of cam assembly 112. As shown, cannula output hole 146 has moved past and stopped overlapping with output port 140. The volume of manifold chamber 108 is at a minimum, as shown as reference number 158, and is ready to repeat the cycle.

[0023] While the present invention has been shown and described with reference to certain exemplary embodiments, it is not limited by the exemplary embodiments, but only by the appended claims and their equivalents. Those skilled in the art will understand that they can change or modify the exemplary embodiments without departing from the scope of the present invention. In addition, features of various embodiments can be combined with each other to form new embodiments without departing from the scope of the present invention.

Claims

1. 1. A pump for medical fluids, comprising: A pump housing; a manifold within the pump housing having a manifold chamber, an input port, and an output port therein; a cannula received within the manifold chamber, the cannula having input and output holes disposed on opposite sides of the cannula and offset along an axis of the cannula corresponding to the locations of the respective input and output ports of the manifold; a cam assembly received within a cam chamber, the cam assembly being fixed to the cannula and adapted to reciprocate the cannula axially when the cam rotates; Equipped with the cam chamber includes a cam surface that contacts a cam surface of the cam assembly; The cam assembly has a pair of cam surfaces formed on the front and back sides that are spaced apart in the direction of the rotation axis of the cam, and the pair of cam surfaces are formed into shapes that increase and decrease in thickness by respectively displacing in directions approaching or separating from each other in the direction of the rotation axis of the cam, and the pair of cam surfaces each contact the cam surface of the cam chamber while rotating in the rotation direction of the cam.

2. 2. The pump of claim 1, wherein the cam chamber is formed from a cam chamber housing having a cam surface and a cam chamber cap having a cam surface.

3. 3. The pump of claim 2, wherein the cam chamber cap includes an axial opening, and the cam assembly includes a motor coupling portion extending through the opening in the cam chamber cap.

4. The pump of claim 1 , wherein the cam assembly is positioned to align the input bore of the cannula with the input port when the manifold chamber is increasing in size.

5. The pump of claim 1 , wherein the cam assembly is positioned to align the output bore of the cannula with the output port when the manifold chamber is decreasing in size.

6. The pump of claim 2 , wherein the cam surface of the cam chamber housing comprises a ramp shape.

7. The pump of claim 2 , wherein the cam surface of the cam chamber cap comprises a ramp shape.

8. The pump of claim 3 , wherein the motor coupling is slidably received within the motor portion.

9. 10. The pump of claim 1, wherein the cam assembly includes a ramp that interacts to axially move the cannula when the cam rotates.

10. The pump of claim 1 , wherein the input port and the output port are on the same side of the manifold chamber.

11. 2. The pump of claim 1, wherein the input and output holes are positioned such that only one of the input and output holes can be aligned with either the input or output port at a given time.

12. The pump of claim 1 , wherein the cannula is formed from metal tubing.

13. 13. The pump of claim 12, wherein the metal tube has a predetermined inner diameter and the cannula reciprocates axially a predetermined distance to form discrete pump volumes.

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