Precision volumetric pump with bellows closure seal

Abstract

A precision positive displacement pump with bellows containment seals provides compliance time performance comparable to conventional pumps with dynamic seals. However, the precision positive displacement pump with bellows containment seals is capable of operating for long service lives with minimal or no maintenance and without a tendency to leak over long service lives.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to U.S. Provisional Patent Application Serial No. 63 / 004,126, filed April 2, 2020, which is incorporated herein by reference as if fully set forth herein. Technical Field

[0003] This disclosure generally relates to precision pumps, and more specifically, to a precision positive displacement pump having a bellows-sealed seal. Background Technology

[0004] Various clinical and diagnostic devices may include one or more precision fluid pumps that operate volumetrically to provide a desired dispensing volume. Such volumetric pumps can be used to pump sample fluids and a variety of reagents, including those containing salts, detergents, or other potentially corrosive or reactive components. For example, salts and detergents can be used to transfer or flush sample fluids without promoting the growth of organic matter, such as on the inner surfaces of the device in fluid communication with such reagents.

[0005] However, exposure to these types of reagents commonly used in various types of analytical instruments can be problematic for the seals of conventional volumetric pumps (e.g., conventional volumetric pumps employing pistons or plungers, including syringe-type volumetric pumps). Such conventional volumetric pumps typically have dynamic seals surrounding the pumping element (e.g., piston or plunger), which are dynamic seals that experience friction or wear between the seal and another surface (e.g., when the plunger is actuated, the seal moves longitudinally, thus rubbing or abrading the surface as it moves). Such dynamic seals can represent a constraint on the lifespan of a conventional volumetric pump due to the degradation of the seal over time caused by friction / wear. In some conventional volumetric pumps, the detergents used often have low surface tension, which can lead to leakage at the seals of the conventional volumetric pump. In another example, brine solutions may tend to form deposits at the seals, which can accelerate the failure of a conventional volumetric pump. Summary of the Invention

[0006] A precision positive displacement pump with a bellows-sealed seal provides a pump with a permanent seal that does not require a dynamic seal, and therefore eliminates various adverse consequences associated with dynamic seals, including but not limited to failure or leakage of the dynamic seal. A precision positive displacement pump according to an aspect of this disclosure may include a bellows bladder positioned within a pump housing and coupled to a drivetrain system. The bellows bladder is hermetically sealed to the drivetrain housing by a static seal and its volume can be adjusted in response to linear movement of a nut (or collar) of the drivetrain. The pump housing may also be hermetically sealed to the drivetrain housing, and the dimensions and shape of the pump housing may be configured such that the bellows bladder is adjustable within the pump housing without contacting the inner surface of the pump housing. The sum of the volume of the bellows bladder and the volume of the pump chamber defined by the space between the inner surface of the pump housing and the bellows bladder remains constant. In other words, as the volume of the bellows bladder increases, the volume of the pump chamber decreases; similarly, as the volume of the bellows bladder decreases, the volume of the pump chamber increases. Attached Figure Description

[0007] To gain a more complete understanding of the invention and its features and advantages, the following description is now taken in conjunction with the accompanying drawings, in which:

[0008] Figure 1 An exploded view of a precision positive displacement pump with a bellows-sealed seal is depicted.

[0009] Figure 2A and Figure 2B The invention describes the process of priming the bellows in a precision positive displacement pump with a bellows-sealed seal to remove air.

[0010] Figure 2C Depicting Figure 2B The amplified portion;

[0011] Figure 2D Depicting Figure 2A , Figure 2B , Figure 2C A perspective view of the bellows bladder;

[0012] Figure 3 A pump compliance test configuration for a precision positive displacement pump with a bellows-sealed seal is described to quantify performance against trapped air in the pump.

[0013] Figure 4 Pump compliance curves, including pressure versus volume, are depicted for a precision positive displacement pump with a bellows-sealed seal.

[0014] Figure 5 Pump compliance curves, including pressure versus time, were plotted for a precision positive displacement pump with a bellows-sealed seal; and

[0015] Figure 6 This is a flowchart of a method for operating a precision positive displacement pump with a bellows-sealed enclosure.

[0016] Figure 7 A perspective view of a precision positive displacement pump with a bellows-sealed seal according to aspects of this disclosure is depicted. Specific Implementation

[0017] In the following description, details are illustrated with the aid of examples to facilitate discussion of the disclosed subject matter. However, it should be apparent to those skilled in the art that the disclosed embodiments are exemplary and not an exhaustive list of all possible embodiments.

[0018] Throughout this disclosure, hyphenated reference numerals refer to specific instances of elements, while non-hyphenated reference numerals refer to general or collective terms for elements. Thus, as an example (not shown in the figures), device "12-1" refers to an instance of a class of devices, which can be collectively referred to as device "12," and any element in that class can be generally referred to as device "12." In the figures and description, the same reference numerals are intended to denote the same elements.

[0019] As previously noted, conventional volumetric pumps used in various types of clinical and diagnostic devices typically include dynamic seals surrounding the pumping elements (e.g., pistons or plungers), which can be a source of leakage and pump failure. Dynamic seals in conventional volumetric pumps can therefore limit reliability and cause premature failure or excessive downtime for servicing, which is economically undesirable. Furthermore, the placement of conventional pumps within clinical and diagnostic devices has been restricted to easily accessible locations to facilitate recurring maintenance, and such devices already include additional safeguards to prevent damage to other device components in the event of undesirable seal leakage in a conventional pump.

[0020] As disclosed herein, a precision positive displacement pump with a bellows-sealed seal as a static seal is a pump that is permanently sealed, eliminating dynamic seals and thus eliminating the various adverse consequences associated with dynamic seals as previously noted. The precision positive displacement pump with a bellows-sealed seal disclosed herein prevents micro-leakage during the pump's operating life. The precision positive displacement pump with a bellows-sealed seal disclosed herein makes it possible to eliminate maintenance plans and, therefore, avoid downtime for pump maintenance. The precision positive displacement pump with a bellows-sealed seal disclosed herein allows analytical instruments using the pump to forgo leak protection measures and leak damage prevention arrangements. The precision positive displacement pump with a bellows-sealed seal disclosed herein allows analytical instruments using the pump to place the pump in any desired location within the instrument, regardless of accessibility for maintenance. The precision positive displacement pump with a bellows-sealed seal disclosed herein can provide operating compliance comparable to conventional pumps with dynamic seals. The precision volumetric pump with a bellows-sealed seal disclosed herein can provide a first operating life at least as long as the second operating life of the analytical instrument in which the pump is used. As used herein, the terms "sealed seal" and "closely sealed" refer to a seal that makes an object airtight at or near atmospheric pressure. As used herein, the term "static seal" refers to a seal that is not dynamic. As used herein, the term "dynamic seal" refers to a seal that experiences friction or wear relative to another surface (e.g., between the walls of a chamber in which the seal moves in response to the actuation of a plunger or piston).

[0021] Now refer to the attached diagram, Figure 1 An exploded view of a precision positive displacement pump 100 (also referred to herein as pump 100) with a bellows-sealed seal, as disclosed herein, is depicted. Figure 1 This is a schematic diagram and is not necessarily drawn to scale or in perspective. Note that some components of pump 100 may be omitted, or may be derived from... Figure 1 It is obstructed when viewed from the perspective of [the viewpoint].

[0022] like Figure 1 As shown, pump 100 includes a motor 102 for controlled rotation. Pump 100 includes a drivetrain system 104, which includes a nut (or collar) 103 and a drivetrain housing 105. In various embodiments, motor 102 may be a stepper motor and may be coupled to the nut 103 of drivetrain system 104 to convert rotation of motor 102 into linear motion of nut 103. Nut 103 may be configured for bidirectional operation, wherein the direction of rotation of motor 102 determines the direction of linear motion of nut 103 relative to motor 102, whether forward or backward, for example in... Figure 1In the coaxial arrangement shown, it should be noted that the shaft 101 of the motor 102 may be equipped with an external thread, which connects to the lead screw 115 positioned within the nut 103 (see also...). Figure 2A Threaded engagement. Nut 103 is positioned within drivetrain housing 105 and is connected to and drives bellows bladder 106 within pump housing 108. Pump housing 108 is sealed to drivetrain housing 105 by a static seal 117. Pump housing 108 may be attached (e.g., by welding, adhesive, seals, or other attachment means) to drivetrain housing 105, wherein static seal 117 is positioned between pump housing and drivetrain housing to provide a tight seal between pump housing 108 and drivetrain housing 105. In some aspects, some or all of pump housing 108 may be transparent or translucent to facilitate viewing of the inflow and outflow of fluid within pump housing 108 and the dispensing of liquid by pump 100. Figure 1 As shown, the bellows bladder 106 is surrounded by and reciprocates (or moves) within the pump housing 108. The pump housing 108 may include at least one external port 114 that is fluidly connected to an external capillary conduit (not shown). Note that in some embodiments, a valve unit (not shown) may be connected at the pump housing 108 to the port 114 to control the operation of the pump 100 relative to the inlet and outlet conduits.

[0023] Still Figure 1 The control module 110 is shown, which may contain electronics enabling the drive motor 102 to control the pump 100. Also visible is a sensor module 112, such as a limit sensor 112-1 and a detector element 112-2, which can be coupled to the drive system 104 and enable monitoring of the movement or pumping action of the bellows bladder 106. In some aspects, the limit sensor 112-1 may include two Hall effect sensors used as limit switches and initial positions for the bellows bladder 106. The limit sensor 112-1 can be calibrated to detect specific field strengths for detecting the magnet ring 118 at a desired location (see [link to documentation]). Figure 2AThe magnet ring 118 can be positioned on the nut 103, and therefore the position of the magnet ring 118 can correspond to the position of the nut 103 and thus the position of the bellows bladder 106. Therefore, the limit sensor 112-1 can be used in conjunction with the magnet ring 118 to prevent over-compression or over-extension of the bellows bladder 106 and allow for repeatable initialization before operation of the pump 100. For example, in the position where the magnet ring 118 is positioned below the first limit sensor in the limit sensor 112-1 (corresponding to a detected predetermined magnetic field strength), the bellows bladder 106 is thus in a fully displaced position, and further extension of the bellows bladder 106 may over-extension and damage the bellows bladder 106. In the position where the magnet ring 118 is positioned below the second limit sensor in the limit sensor 112-1 (corresponding to a detected predetermined magnetic field strength), the bellows bladder 106 is thus in a fully vented position, and further compression of the bellows bladder 106 may damage the bellows bladder 106.

[0024] like Figure 1 As shown, the bellows bladder 106 may include a series of individual swivels 106-1 (see also...) Figure 2B The series of individual swivels may be annular and may be attached to each other, for example by welding or by using another suitable bonding technique. The swivels 106-1 of the bellows 106 may comprise a material having sufficient strength, elasticity, and hydrophilicity. In some examples, the swivels 106-1 of the bellows 106 may comprise metallic materials such as aluminum, stainless steel, titanium (including combinations of metals), or may comprise another material, such as a polymer, having substantially similar properties regarding strength, elasticity, and hydrophilicity. In some aspects, the bellows 106 may comprise a material having a yield strength between about 200 and about 600 MPa. In some aspects, the bellows 106 may have an elastic modulus between about 100 and about 225 GPA. In some aspects, the swivels 106-1 may have an elastic modulus between about 700 and about 1100 J / m². 2 The surface energy between them. In some aspects, the hydrophilic properties of the swirl portion 106-1 can be achieved via a coating or surface treatment on the surface of the swirl portion 106-1. In some aspects, the swirl portion 106-1 may comprise 316L stainless steel. Each swirl portion 106-1 may accordingly have weld overlays at its inner radial edge and outer radial (or circumferential) edge. Due to the annular shape of the individual swirl portion 106-1, the combination of the inner radial edges forms an internal passage within the bellows bladder 106 (in Figure 1 Not visible in the middle, see also Figure 2AWhen these components are connected as a whole, the individual swivel sections 106-1 can form a bellows bladder 106, which forms a spring-like sealing structure that allows for expansion and contraction, thereby precisely adjusting its volume. In other words, the bellows bladder 106 can expand and contract, thereby increasing or decreasing its outer surface area and consequently increasing or decreasing its volume.

[0025] As shown in the figure, the bellows bladder 106 can be attached to the drive shaft 116 at one end region 107. Figure 1 Not visible in the middle, see also Figure 2A , Figure 2B , Figure 2C The drive shaft 116 extends radially to form an end plate 116-1. The drive shaft 116 can pass through the internal passage of the bellows bladder 106 and is coupled to the drivetrain system 104 at an end region 109 of the drive shaft 116 opposite to the end plate 116-1. The opposite end region 111 of the bellows bladder 106 can be attached to the drivetrain housing 105, as shown. The joint or connection between the bellows bladder 106 and the end plate 116-1 and the drivetrain housing 105 can be a hermetically sealed solid joint, such as by welding, or other types of joints.

[0026] like Figure 1 As shown, the pump housing 108 forms a relatively thick-walled pump chamber 204 that seals and surrounds the bellows bladder 106. Therefore, the pump housing 108 is attached to the drivetrain housing 105 at an end region 113, which has a corresponding opening in the pump housing 108 to receive the bellows bladder 106. It should be noted that the pump housing 108 has a fixed seal with the drivetrain housing 105, where the bellows bladder 106 is also attached. However, the pump housing 108 does not contact the bellows bladder 106 and does not form a seal with it, which is achieved by the pump chamber 204 formed internally by the pump housing 108 (from...). Figure 1 When viewed from a certain perspective, the viewpoint is obstructed; see [link / reference]. Figure 2A It can move freely within (i.e., adjust or expand and contract) and is further described below. Figure 1 Also visible is port 114, which allows for fluid communication with a capillary conduit or a valve module (not shown). Port 114 is in fluid communication with pump chamber 204, as discussed regarding... Figure 2A and Figure 2B As shown.

[0027] In operation of pump 100, pump chamber 204 can be initially filled with a volumetrically metered liquid for startup, while bellows bladder 106 can at least partially contract to increase the volume of pump chamber 204, which corresponds to the volume between the wall of pump housing 108 and bellows bladder 106. For example, one of the ports 114 can be used to draw liquid into pump chamber 204. After startup filling of pump chamber 204 with liquid and evacuating any air remaining in pump chamber 204, motor 102 can be operated to extend bellows bladder 106 to a specific volume within pump chamber 204 (relative to pump housing 108), which corresponds to the volume of liquid dispensed by one of the ports 114 used as an output conduit for pump 100. Specifically, as drive shaft 116 extends, bellows bladder 106 expands within pump chamber 204 and reduces the volume of pump chamber 204, thereby discharging a desired volume of liquid. For example, when the bellows bladder 106 expands and contracts to adjust the first volume, thereby causing a corresponding adjustment of the second volume, the sum of the first volume of the bellows bladder 106 and the second volume of the pump chamber 204 can remain constant. Furthermore, the force provided by the motor 102 can be converted into pressure applied to the pump chamber 204 (the second volume) by the bellows bladder 106. It should be noted that the bellows bladder 106 moves freely within the pump chamber 204 and does not contact any surface of the pump chamber 204, and therefore does not dynamically seal with the pump chamber 204.

[0028] The operation of motor 102 can generate increased heat. To prevent damage or wear to pump 100 components due to the increased heat output by motor 102 during operation, pump 100 can also provide improved heat dissipation. For example, drivetrain housing 105 may include fins 119 that promote efficient convective cooling during pump 100 operation by transferring heat away from motor 102, lead screw 115, and bellows bladder 106. Furthermore, nut 103 may also include fins 121 that also promote efficient convective cooling during pump 100 operation by transferring heat away from motor 102, lead screw 115, and bellows bladder 106. Reducing the temperature on bearing surfaces can extend the lubrication life and performance of pump 100. In addition, the heat exchange provided by fins 119 and 121 can reduce the impact of heat transfer from motor 102 through drivetrain housing 105 and lead screw 115 to the fluid in pump 100. In some respects, the use of at least some fins (e.g., but not limited to fin 119) on the drivetrain body can reduce the temperature at the end region 107 of the bellows bladder 106 by about five to about 15 degrees Celsius. Furthermore, the material of the pump housing 108 can also improve heat dissipation; for example, using a thermally conductive material for the pump housing 108 can reduce the temperature of the lead screw 115 and the motor 102 by about 9 degrees Celsius during pump operation. Examples of thermally conductive materials that can be used for the pump housing 108 may include, but are not limited to, aluminum, stainless steel, or composites or thermally conductive polymers.

[0029] Although Figures 1 to 2C The pump 100 depicted in the illustration features a specific number and orientation of fins 119 and fins 121; however, in other aspects of this disclosure, different numbers and orientations of fins may be used. For example, Figure 7 A perspective view of a pump 700 according to aspects of this disclosure is depicted. Pump 700 includes a drive housing 702 that includes fins 704 for heat dissipation. The fins 704 differ in size, shape, number, and orientation from the fins 119 of pump 100, but still provide heat dissipation. Additional fins of different sizes, shapes, numbers, and orientations are contemplated for the pump disclosed herein. Pump 700 also includes a motor 706 and a pump housing 708 within which a bellows bladder 710 extends. Pump housing 708 is transparent to allow viewing of the pump 700's intake and dispensing of fluid. Pump 700 may include all or some of the features of pump 100 and operate in the same manner as pump 100. Pumps 100 and 700 are shown and disclosed herein as including static seals; however, in some aspects, without departing from the scope of this disclosure, static seals may be replaced with dynamic seals, or dynamic seals may be included in pump 100 and / or pump 700.

[0030] See now Figure 2A A cross-sectional view of a precision positive displacement pump 100 with a bellows-sealed seal is shown. Figure 2AThis is a schematic diagram and is not necessarily drawn to scale or in perspective. Note that some components of pump 100 may be omitted, or may be derived from... Figure 2A The sectional view provided is obscured during viewing. Figure 2A The cross-section shows a motor 102, a transmission system 104 including a nut 103 and a lead screw 115 and a transmission housing 105, a pump housing 108 and a bellows bladder 106, and more. Figure 2A Other components of the pump in its assembled state, as depicted in the image, and corresponding to... Figure 1 The exploded diagram is shown in Figure 100-1.

[0031] It should be noted that the bellows bladder 106 may be equipped with certain features that enhance reliability and prevent damage or undesirable operation. Specifically, the drive shaft 116 and the end plate 116-1 may be designed to prevent any rotation of the bellows bladder 106, which is desirable to prevent uncontrolled dispensing actions or dispensing errors, such as when the direction of movement of the drive shaft 116 is changed. Furthermore, the bellows bladder 106 may be preloaded onto the drive shaft 116 relative to the elastic force applied by the bellows bladder 106. Therefore, the drive threads driving the drive shaft 116 can withstand continuous force in one direction, which can substantially reduce or eliminate backlash or other mechanical uncertainties in the operation of the drivetrain system 104.

[0032] Furthermore, the welds used to connect or join the swivel sections 106-1 together form a solid, homogeneous barrier to prevent leakage of the pumped fluid. This solid-state seal provided by the bellows bladder 106 eliminates the dynamic seals that slide across the mating sealing surfaces used in conventional pump designs. Therefore, the solid-state seal provided by the bellows bladder 106 is unaffected by variations in the mating sealing surfaces or micro-topology, and is not subject to dynamic wear of the mating sealing surfaces during operation, resulting in a more reliable design for the pump 100.

[0033] exist Figure 2A In the diagram, pump 100 is depicted in an initiation and filling configuration, and accordingly, pump 100 is arranged at an angle 216 relative to a horizontal surface so that one end of pump 100 is raised. Figure 2AThe raised end of the pump 100 shown includes a pump chamber 204 and ports 114, shown as a first port 114-1 and a second port 114-2. As shown in cross-sectional view 100-2, the drive shaft 116 and the bellows bladder 106 contract, while the pump chamber 204 is correspondingly enlarged. As shown, the first port 114-1 is open to allow liquid to fill the pump chamber 204 as the bellows bladder 106 contracts and expands the volume of the pump chamber 204 within the pump housing 108. A valve unit (not shown) with corresponding valves to open or close each of ports 114-1 and 114-2 can be used, for example, by direct attachment to the pump housing 108. The valve unit may include, for example, a solenoid valve.

[0034] like Figure 2A As shown in the cross-sectional view, as a result of the pump 100 being oriented at an angle 216, the second port 114-2 is higher than the first port 114-2, and the fluid within the pump chamber 204 has an angled surface as the fluid level rises, creating an angled void 208 containing air. The angled void 208 is in fluid communication with the second port 114-2 and serves to collect air bubbles 202 that may be present in the fluid at the highest point. Therefore, after fluid is drawn into the pump chamber 204 and the bellows bladder 106 begins to expand again, the angled void 208 begins to decrease in volume as air is distributed through the second port 114-2, thereby removing air from the pump chamber 204. After the air is removed and the pump chamber 204 is filled with fluid, the pump 100 can be considered to have been started and is ready to precisely dispense fluid by volume through the second port 114-2, for example, when the first port 114-1 is closed (see also...). Figure 2B ).

[0035] Now for reference Figure 2B A precision positive displacement pump 100 with a bellows-sealed seal is shown in cross-section. Figure 2A The position of the bellows bladder 106 is compared to the bellows bladder 106 in the expanded position. Figure 2B This is a schematic diagram and is not necessarily drawn to scale or in perspective. Note that some components of pump 100 may be omitted, or may be derived from... Figure 2B It is obstructed when viewed from the perspective of [the viewpoint]. Figure 2B The pump housing 108 and the pump chamber 204 are described in further detail and correspond to Figure 2A A partially enlarged sectional view, in which the bellows bladder 106 and Figure 2A The position of the bellows bladder 106 is in the expanded position compared to the previous position.

[0036] exist Figure 2B In this configuration, the first port 114-1 can be closed, while the second port 114-2 can be used as an output port to distribute fluid in the pump chamber 204. Figure 2AIn comparison, Figure 2B In this configuration, the bellows bladder 106 expands with an increased volume, while the pump chamber 204 has a decreased volume. Figure 2A and Figure 2B The amount by which the volume of the pump chamber 204 has decreased corresponds to the amount of fluid that has been distributed. Furthermore, in Figure 2B In the middle, the air bubble 202 evacuated through the second port 114-2 is visible, as mentioned above. Figure 2A As stated above.

[0037] Still Figure 2B and Figure 2D The bellows bladder 106, as described above, is mounted to the drive shaft 116 and end plate 116-1 in further detail; for clarity, this is shown in an isolated perspective view. Figure 2D Also visible is the central opening of the receiving drive shaft 116 in the bellows bladder 106. Figure 2C This is an exploded view of a portion 220 of the bellows 106 106, depicting a plurality of swirls 106-1. The area of ​​exploded view 220 is shown in views 100-3 and corresponds to the outer edge of the bellows 106 106. Exploded view 220 depicts the effect of the hydrophilic surface of the swirls 106-1 allowing capillary suction of fluid in small gaps between the individual swirls 106-1. As fluid is capillarily drawn along the hydrophilic surface of the swirls 106-1, any air trapped therein can be displaced and can escape in the form of air bubbles 202 discharged at the second port 114-2. As a result of these features, the pump 100 can be started and filled to remove air bubbles in the pump chamber 204, as desired, and provides precise volumetric operation with low compliance time.

[0038] Now for reference Figure 3 A pump compliance test configuration 300 is shown in a schematic process diagram. For example, test configuration 300 can be used to quantify the air in pump 100 after performing the process described above for starting pump 100, filling it with fluid, and removing air bubbles 202. As shown, test configuration 300 includes pump 100 having a first port 114-1 and a second port 114-2. For the purposes of test configuration 300, it can be assumed that the first port 114-1 is closed, pump 100 is filled with fluid to be dispensed, and the second port 114-2 is open. Therefore, a conduit extending from the second port 114-2 can be in fluid communication with a first valve 304 that implements receiving air injection 302. The first valve 304 is connected to a holding circuit 306 that increases the volume of the conduit path, which is also in fluid communication with a pressure sensor 308. Additionally, the second valve 310 can be used as an output valve to discharge fluid into capillary 312 (or another fluid reservoir in various embodiments).

[0039] During the operation of test configuration 300, while the second valve 310 is closed, a defined volume of air can be injected at air injection 302 into the subsequently closed first valve 304. In a compliance test, the second valve 310 can be opened and the pumping pressure can be measured relative to the fluid volume dispensed during pump 100 operation (see also...). Figure 4 In this way, various compliance curves of pressure relative to the allocated volume can be recorded and used for comparison with measured compliance curves of pressure relative to the allocated volume of pump 100 under operating conditions. For example, by comparing the measured compliance curve of pressure relative to the allocated volume with a reference curve, the amount of air that may be trapped within pump 100 can be determined. In this way, it can be determined when pump 100 is completely evacuated, as this is desirable for optimal operation.

[0040] In another compliance test using test configuration 300, both the first valve 304 and the second valve 310 can remain closed while the pump 100 is operating. The pressure sensor 308 can then be used to record the pressure rise over time, thus generating a pressure compliance time profile (see also...). Figure 5 In this way, the pressure compliance time curves for different pumps can be measured and used to characterize pump performance.

[0041] Now for reference Figure 4 The pressure-volume compliance graph 400 shows different compliance curves of pressure relative to the allocated volume. In the pressure-volume compliance graph 400, curves 402, 404, and 406 show the level of pumping conditions as the volume of air injected into the pump increases. The curves shown in graph 400 are indicative of the pump 100 and can be used with reference to the above. Figure 3 The test configuration 300 shown and described is used for measurement. Specifically, curve 402 can show measurement data for no trapped air and can represent a minimum curve or a reference curve. Therefore, when a curve similar to curve 402 is measured for the pump, it can be assumed that the pump is operating without any internal trapped air, which is desirable. Curve 404 can show a first air volume greater than that of curve 402 (no trapped air). Curve 406 can show a second air volume greater than that of curve 404 with the first air volume. Although direct comparisons can be made using the curves, another metric, using a reference pressure level shown as Pref in curve 400, can be used for a simpler quantitative evaluation of the curves in curve 400. For example, the volume allocated at the reference pressure Pref can be used as a quantitative metric for evaluating trapped air in pump 100. Thus, curve 402 will show the minimum allocated volume at Pref, followed by curve 404, and then curve 406.

[0042] Now for reference Figure 5 The pressure compliance time curves are shown in Figure 500. In Figure 500, compliance time curves 502, 504, and 506 show different compliance times for different pump designs under the same conditions. Compliance time can represent the response time of a pump to reach a steady-state volume distribution rate (e.g., flow rate). Specifically, compliance time curve 504 describes a conventional pump with a dynamic seal, such as the piston pump corresponding to curve 504. Compliance time curves 502 and 506 describe the compliance time behavior for the precision positive displacement pumps disclosed herein. For example, compliance time curve 506 describes the compliance time behavior for a precision positive displacement pump 100 with a bellows-sealed seal as disclosed herein. As is evident in the pressure compliance time graph 500, the compliance time for the precision positive displacement pump 100 (including but not limited to the precision positive displacement pump 100) according to embodiments of the present disclosure can be comparable to that of a conventional pump with dynamic seals, which is desirable and indicates that the pump 100 is able to perform without sacrificing pump performance compared to conventional pump designs.

[0043] The precision positive displacement pump 100 with a bellows-sealed seal disclosed herein offers unique features and benefits compared to conventional or other types of precision positive displacement pumps. The geometry, span (e.g., diameter of the swivel section), and material composition of the bellows bladder 106 can be selected to minimize compliance time during operation as pressure increases or decreases. Compliance time determines the time it takes for the pressure to stabilize during and after the pump's precision dispensing operation. Although a hollow cylindrical geometry of the bellows bladder 106 is shown and described herein for clarity, it should be noted that other shapes or geometries of the bellows bladder can be used in various implementations. Regarding materials, a corrosion-resistant metallic composition of the bellows bladder 106 is shown and described herein. The hydrophilic surface of the swivel section 106-1 is also described herein, which can be achieved using various types of surface treatments or coatings, particularly when dispensing corresponding aqueous liquids; for example, surface treatments can improve chemical resistance. In some aspects of this disclosure, the bellows bladder 106 (e.g., the outer surface of the bellows bladder 106) may undergo metal passivation, such as, but not limited to, nitric acid passivation following the manufacturing welding process that forms the bellows bladder 106. Nitric acid passivation of the bellows bladder 106 provides a passivated outer surface (e.g., defined by the swivel portion 106-1), and this can help prevent corrosion of the bellows bladder 106, for example, during cleaning of the pump 100 (when the bellows bladder 106 may be exposed to sodium hypochlorite or other corrosive chemicals). Preventing corrosion of the bellows bladder 106 can help prevent pump 100 failure over time.

[0044] Furthermore, the material, solder ball type, and swirl spacing (e.g., swirl pitch) can be selected to promote surface wetting and minimize or eliminate trapped air during pump 100 start-up and dispensing, and such design features can be selected depending on the liquid that pump 100 is designed to dispense. As noted above, any trapped air within pump 100 or in the transport system fluidly connected to pump 100 can adversely affect dispensing volume accuracy and compliant-time behavior. Moreover, the stroke length of bellows 106, along with mechanical properties (e.g., stiffness) and the number of swirls 106-1, can be selected to optimize (e.g., extend or maximize) the service life of the bellows 106's sealing seal to prevent surface crack propagation due to material fatigue. In this way, the specific design of bellows 106 can enable pump 100 to exceed instrument service life requirements with a high degree of confidence. For example, it should be noted that accelerated fatigue testing of bellows 106 has shown that pump 100 can have a service life exceeding 12 million cycles.

[0045] As disclosed herein, the precision positive displacement pump 100 with a bellows-sealed seal provides time-response performance comparable to that of a conventional pump with a dynamic seal. However, the precision positive displacement pump with the bellows-sealed seal is capable of operating with minimal or no maintenance for a long service life without any tendency to leak over that long service life.

[0046] Figure 6 A flowchart depicts a method 600 for operating a precision positive displacement pump (e.g., but not limited to pump 100) with a bellows-sealed seal. Method 600 may include, at step 602, controlling a motor to generate rotational movement of a drivetrain (e.g., but not limited to drivetrain system 104) that converts this rotational movement into linear movement. At step 604, the method may include driving a bellows bladder (e.g., but not limited to bellows bladder 106) according to the linear movement. The bellows is hermetically sealed relative to the drivetrain. At step 606, the method may include adjusting a first volume of the bellows bladder according to the linear movement. Step 608 of method 600 may include adjusting a second volume of a pump housing (e.g., but not limited to pump housing 108) or a chamber, wherein the pump housing does not contact the bellows bladder when the first volume is adjusted, and wherein the sum of the first volume of the bellows bladder and the second volume of the pump housing remains constant.

[0047] The precision bellows pumps disclosed herein (e.g., but not limited to pumps 100 and 700) can provide precise dispensing of small volumes of liquid. For example, the precision bellows pumps contemplated in this disclosure can provide dispensing of liquids between about 1 μl and about 5000 μl (e.g., but not limited to liquids between about 500 μl and about 2500 μl). The pumps contemplated in this disclosure (including, but not limited to, pumps 100 and 700) can dispense liquid with an accuracy of 0.01% for full-volume dispensing (i.e., dispensing or stroke of the entire volume of the bellows pump). As used herein, “accuracy” or “accuracy value” refers to the average repeatability between strokes of a particular volume dispensing. The pumps contemplated in this disclosure (including, but not limited to, pumps 100 and 700) can deliver a predetermined volume per cycle with an accuracy of less than 1% for 2% of the full-volume dispensing. In certain aspects of the pumps envisioned herein (including, but not limited to, pump 100 and pump 700), a predetermined volume can be delivered per cycle with an accuracy value as shown in Table 1.1 below for the corresponding volumetric allocation (or stroke) (hereinafter shown as a percentage of the pump's total volumetric allocation):

[0048]

[0049]

[0050] In some respects, the precision pumps disclosed herein (including, but not limited to, pump 100 and pump 700) can have accuracy values ​​for various strokes according to the equation provided below, where accuracy is expressed as %CV (variance coefficient) and %CV = 9E-05 x (% stroke)^-0.67:

[0051] CV = σ / μ

[0052] Where σ = standard deviation, μ = mean

[0053] The pumps (including, but not limited to, pump 100 and pump 700) contemplated in this disclosure can operate at a flow rate between about 500 μl / min and about 300 ml / min.

[0054] The pumps disclosed herein (including, but not limited to, pump 100 and pump 700) are contemplated for use with a variety of clinical and diagnostic instruments and systems (e.g., but not limited to fluid infusion devices), biological processing and pharmaceutical systems, clinical chemistry, immunoassay, hematology, molecular diagnostics, regularly spaced clustered short palindromic repeats (“CRISPR”), sample preparation, gene sequencing, space biology, polymerase chain reaction (“PCR”), and HbA1c testing and processing, and similar applications. In some aspects, a precision volumetric pump according to one or more of the following examples is provided:

[0055] Example #1: A precision positive displacement pump may include a bellows bladder that is expandable and contractable to adjust a first volume of the bellows bladder, wherein the bellows bladder is hermetically sealed relative to a drivetrain housing. The pump may also include a pump housing defining a chamber with a second volume, the chamber being hermetically sealed relative to the drivetrain housing to accommodate the bellows bladder when the pump housing is mounted to the bellows bladder, wherein the pump housing does not contact the bellows bladder when the bellows bladder adjusts the first volume, and wherein the sum of the first volume and the second volume remains constant. Additionally, the seal positioned between the pump housing and the drivetrain housing may be a static seal.

[0056] Example #2: The precision positive displacement pump of Example 1 is further characterized by having a drive system connected to the bellows bladder so that the bellows bladder can linearly expand and contract in response to rotational motion. Additionally, the drive system may be located within a drive system housing. The pump may also include a motor that provides the rotational motion to the drive system.

[0057] Example #3: A precision volumetric pump as described in any of Examples 1 to 2, characterized in that the bellows bladder further includes a plurality of swirl sections, the plurality of swirl sections being connected together by material bonding at the respective edges of the swirl sections.

[0058] Example #4: A precision volumetric pump as in Example #3, further characterized in that the surface portions of the plurality of swirling sections include hydrophilic surfaces.

[0059] Example #5: A precision volumetric pump as in Example #3, further characterized in that the pump housing includes a port to allow air bubbles to be removed from the chamber of the pump housing when the precision volumetric pump is tilted at an angle.

[0060] Example #6: A precision volumetric pump as in Example #3, characterized in that the swivel section comprises a metallic material, and the material joint comprises a weld.

[0061] Example #7: A precision volumetric pump as described in any of Examples #1 to #6, characterized in that the bellows bladder achieves a service life of at least 7 million cycles.

[0062] Example #8: A precision volumetric pump as described in any of Examples #1 to #7, characterized in that the bellows bladder includes a surface treatment for improving chemical resistance on the outer surface of the bellows bladder.

[0063] Example #9: A precision volumetric pump as described in any of Examples #1 to #8, characterized in that the outer surface of the bellows bladder comprises a passivated metallic material.

[0064] Example #10: A precision volumetric pump as described in any of Examples #1 to #9, characterized in that the bellows bladder is prevented from rotating during operation.

[0065] Example #11: A precision volumetric pump as described in any of Examples #1 to #10, further characterized by a drive system, wherein the drive system may also include a threaded connection between the motor and the bellows bladder.

[0066] Example #12: A precision volumetric pump as in Example #11, further characterized in that the threaded connection is preloaded with a linear force provided by the bellows bladder.

[0067] Example #13: A precision volumetric pump as in any of Examples #1 to #12, characterized in that the pump delivers a predetermined volume per cycle for 2% of the total volumetric distribution with an accuracy of less than 1%.

[0068] Example #14: A precision volumetric pump as in any of Examples #1 to #13, characterized in that the pump delivers a predetermined volume per cycle for 1% of the total volumetric distribution with an accuracy of approximately 0.2%.

[0069] Example #15: A precision volumetric pump like that in Example #3, characterized in that multiple swirling sections include the same shape or size.

[0070] Example #16: A precision volumetric pump as described in any of Examples #1 to #15, characterized in that the pump is adapted to deliver 0.1% to 100% of the liquid volume of the full 500 μl pump per cycle.

[0071] Example #17: A precision volumetric pump as in any of Examples #1 to #16, wherein the pump is adapted to deliver 0.1% to 100% of the full 2500 μl pump volume per cycle.

[0072] Example #18: A precision volumetric pump as described in any of Examples #1 to #17, characterized in that the pump is capable of operating in a pressure range from vacuum to 100 PSI.

[0073] Example #19: A method of operating a precision positive displacement pump may include controlling a motor to generate rotational movement, converting the rotational movement into linear movement via a drivetrain, and driving a bellows bladder hermetically sealed relative to the drivetrain housing according to the linear movement. The method further includes adjusting a first volume of the bellows bladder according to the linear movement in response to driving the bellows bladder, and adjusting a second volume of a pump chamber of a pump housing in response to adjusting the first volume, wherein the pump housing is hermetically sealed to the drivetrain housing. The method further includes positioning the bellows bladder within the pump chamber of the pump housing such that the pump housing does not contact the bellows bladder when the first volume is adjusted, and wherein the sum of the first volume and the second volume remains constant.

[0074] Example #20: The method of Example #19 is further characterized by transferring the rotational movement of the motor to the drive system via a threaded connection between the drive system and the motor; and by connecting the drive system to the bellows bladder and preventing rotation of the bellows bladder relative to the drive system, the bellows bladder is able to expand and contract linearly in response to the linear movement of the drive system.

[0075] Example #21: The method of Example #20 further includes the bellows bladder having a plurality of swirls, the plurality of swirls being connected together at corresponding edges of the swirls by a material bond.

[0076] Example #22: The method of any one of Examples #20 to #21 further includes a surface portion of the swirling portion comprising a hydrophilic surface.

[0077] Example #23: The method of Example #21 is further characterized in that the plurality of swivels comprise metal and the material bonding comprises a weld.

[0078] Example #24: The method of any of Examples #19 to #23 is further characterized by a service life of at least 7 million cycles using the bellows bladder.

[0079] Example #25: The method of any one of Examples #19 to #24 is further characterized in that the outer surface of the bellows bladder comprises a passivated metallic material.

[0080] Example #26: The method of any of Examples #1 to #25 is further characterized by removing air bubbles from the pump housing via a port.

[0081] Example #27: The method of Example #20 is further characterized by transferring the rotational movement of the motor to the drive system via a threaded connection between the drive system and the motor, and also includes rotating the threaded connection under preload of a linear force provided by the bellows bladder.

[0082] Example #28: The method of any one of Examples #19 to #27 is further characterized in that the pump delivers a volume of 500 μl or 2,500 μl per cycle.

[0083] Example #29: The method of any one of Examples #19 to #28, further characterized in that the pump delivers a volume between 250 μl and 5,000 μl per cycle.

[0084] Example #30: The method of any one of Examples #19 to #29 is further characterized in that the pump delivers a predetermined volume per cycle for full volumetric dispensing with an accuracy value of 0.01%.

[0085] The subject matter disclosed above should be considered illustrative rather than restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments falling within the true spirit and scope of this disclosure. Therefore, to the fullest extent permitted by law, the scope of this disclosure shall be determined by the broadest permissible interpretation of the appended claims and their equivalents, and should not be limited to or construed as described in the foregoing detailed description.

Claims

1. A precision positive displacement pump, comprising: A bellows bladder comprising a plurality of individual swivel sections, each of the plurality of individual swivel sections being connected by metal welding to at least one other of the plurality of individual swivel sections, wherein the bellows bladder is expandable and contractable to adjust a first volume of the bellows bladder, wherein the bellows bladder is hermetically sealed relative to the drivetrain housing of the drivetrain system, and wherein each of the plurality of individual swivel sections comprises metal, and wherein each individual swivel section comprises an annular shape; A pump housing defining a chamber in which the bellows bladder is positioned, wherein the pump housing is hermetically sealed relative to the drivetrain housing via a seal positioned between the pump housing and the drivetrain housing, wherein the inner surface of the pump housing does not contact the bellows bladder when the bellows bladder adjusts the first volume, wherein the chamber of the pump housing, the front surface of the drivetrain housing, and the plurality of individual swivel portions of the bellows bladder together define a fluid chamber having a second volume, and wherein the sum of the first volume and the second volume remains constant; An end plate, the end plate being connected to a first end of the bellows bladder and to a shaft, wherein the seal positioned between the pump housing and the drivetrain housing is a static seal; A drivetrain system having a threaded connection between a motor and a bellows, the drivetrain system comprising: A nut, which is positioned within the drivetrain housing and connected to the bellows bladder via the shaft, is capable of moving in a linear direction in response to actuation of the motor; A lead screw positioned within a nut, the lead screw including threads that engage with an additional shaft connected to a motor, for converting the rotation of the motor into linear motion of the nut; and The pump delivers a predetermined volume per cycle for 2% of the full volumetric dispensing with an accuracy of less than 1%, wherein the full volumetric dispensing includes a range from 1 μl to 5000 μl.

2. The precision positive displacement pump according to claim 1, wherein, The surface portions of the plurality of individual swirling sections include hydrophilic surfaces.

3. The precision positive displacement pump according to claim 1, wherein, The bellows bladder achieves a service life of at least 7 million cycles.

4. The precision positive displacement pump according to claim 1, wherein, The corrugated tube includes a hydrophilic surface treatment on the outer surface of the corrugated tube.

5. The precision positive displacement pump according to claim 4, wherein, The outer surface of the bellows bladder includes a passivated metal material for improving chemical resistance.

6. The precision positive displacement pump according to claim 1, wherein, The bellows bladder is prevented from rotating during operation.

7. The precision positive displacement pump according to claim 1, wherein, The bellows bladder is fixed in rotation relative to the threaded connection.

8. The precision positive displacement pump according to claim 7, wherein, The threaded connection between the bellows bladder and the motor is preloaded with a linear force provided by the bellows bladder.

9. The precision positive displacement pump according to claim 1, wherein, The pump delivers a predetermined volume per cycle for 1% of the full volumetric distribution with an accuracy of 0.2%.

10. The precision positive displacement pump according to claim 1, wherein, Each of the plurality of individual spiral sections comprises the same shape or the same size.

11. The precision positive displacement pump according to claim 1, wherein, The pump is adapted to deliver 0.1% to 100% of the full 500 µl pump volume per cycle.

12. The precision positive displacement pump according to claim 1, wherein, The pump is adapted to deliver 0.1% to 100% of the full 2500 µl pump volume per cycle.

13. The precision positive displacement pump according to claim 1, wherein, The pump can operate in a pressure range from vacuum to 100 PSI.

14. The precision positive displacement pump according to claim 1, wherein, At least a portion of the pump housing is adapted to allow observation of the fluid within the pump housing.

15. The precision positive displacement pump according to claim 1, wherein, The pump housing includes at least one external port adapted for fluid communication with an external capillary.

16. The precision volumetric pump of claim 1 further includes a limit sensor connected to the drive system.

17. The precision positive displacement pump according to claim 16, wherein, The limit sensor includes a Hall effect sensor and is adapted to prevent at least one of over-compression or over-extension of the bellows bladder.

18. The precision volumetric pump of claim 16, further comprising an additional limit sensor coupled to the drivetrain system for preventing either over-compression or over-extension of the bellows bladder.

19. The precision positive displacement pump according to claim 1, wherein, The bellows bladder comprises a material having a yield strength between 200 MPa and 600 MPa.

20. The precision positive displacement pump according to claim 1, further comprising a shaft positioned within an internal channel of the bellows bladder, wherein, The shaft is connected at a first end to an end plate of the bellows bladder, wherein the shaft moves in a linear direction in response to the actuation of the motor to control the expansion and contraction of the bellows bladder, thereby adjusting the first volume of the bellows bladder.

21. The precision positive displacement pump according to claim 1, wherein, The pump delivers a predetermined volume per cycle with an accuracy of 1% for 0.01% of the full volumetric distribution.

22. The precision positive displacement pump according to claim 1, wherein, The pump delivers a predetermined volume per cycle for 10% of the full volumetric distribution with an accuracy of 0.04%.

23. The precision positive displacement pump according to claim 1, wherein, The pump delivers a predetermined volume per cycle with an accuracy of 0.01% for 100% of the full volumetric distribution.

24. The precision positive displacement pump according to claim 1, wherein, The pump delivers a liquid volume between 0.1% and 100% of the total pump volume per cycle, wherein the pump delivers a volume between 500 μl and 2500 μl per 100% of the total pump volume per cycle.

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