US20240218866A1

US20240218866A1 - Macro-fluidic and micro-fluidic systems and methods using magnetoactive soft materials

Info

Publication number: US20240218866A1
Application number: US18/391,462
Authority: US
Inventors: Sergey Aleksandrovich Dryga
Original assignee: Q Biotech Corp
Current assignee: Q Biotech Corp
Priority date: 2022-12-29
Filing date: 2023-12-20
Publication date: 2024-07-04
Also published as: WO2024145521A1

Abstract

A linear peristaltic pump can include a first electromagnet operable to pump a fluid through a first cavity of a flexible conduit by repeatedly compressing the first cavity in a first sequence, a second electromagnet operable to pump the fluid through a second cavity of the flexible conduit by repeatedly compressing the second cavity in a second sequence, and a third electromagnet operable to pump the fluid through a third cavity of the flexible conduit by repeatedly compressing the third cavity in a third sequence. The electromagnets may compress the cavities by applying magnetic fields to a magnetoactive elastomer.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation in part of U.S. patent application Ser. No. 18/529,989 filed Dec. 5, 2023 and titled “SELF CALIBRATING PERISTALTIC PUMP WITH REDUCED FLUID PULSES”, claims the priority and benefit of U.S. provisional patent application 63/436,087 filed Dec. 29, 2022 and titled “SELF-CALIBRATING LINEAR PERISTALTIC PUMP WITH REDUCED FLUID PULSATION”, and claims the priority and benefit of U.S. provisional patent application 63/436,542 filed Dec. 31, 2022 and titled “MAGNETICALLY RESPONSIVE ELASTOMER MATERIAL AND USES THEREOF”. U.S. patent application Ser. No. 18/529,989, U.S. provisional patent application 63/436,087, and U.S. provisional patent application 63/436,542 are herein incorporated by reference in their entirety.

TECHNICAL FIELD

The systems and methods relate to magnetoactive soft material (MSM), magnetic field driven actuation, macro-fluidics, micro-fluidics, peristaltic pumps, linear peristaltic pumps, actuators, actuator controllers and sequencers, and to MSM actuator timing and sequencing to reduce the pulsations in a fluid pumped by a peristaltic pump.

BACKGROUND

Linear peristaltic pumps are well known in the art. The principle of action of most linear peristaltic pumps is pushing fluid along a flexible conduit (e.g., a flexible tube or hose) by a wave-like motion of several fingers or pistons arranged in a linear pattern along the conduit. The linear peristaltic pump design addresses several issues characteristic of the circular peristaltic pump, although some issues remain. One of the key performance issues of the peristaltic pump is the pulsating nature of the fluid flow. The pulsation arises due to pressure fluctuation as the wave-like motion of the fingers reaches the end of the pump and the outside finger is lifted. Additionally, the wave-like motion creates an area of increased pressure inside the flexible conduit or tubing between pinch points, thus leading to excessive wear of the flexible conduit. The pulsating nature of the fluid flow is well recognized in the art. The number of fingers that are used in the pump can be increased to reduce the pulsation, with the number of fingers often between 10 and 14. U.S. Pat. No. 4,909,710 proposes reducing the pulsation by moving the two outside fingers faster than the other fingers to increase the frequency of and reduce the magnitude of the pulsations.
Magnetorheological (MR) elastomers can have microscopic ferromagnetic particles embedded in a polymer matrix. MR elastomers have been used in applications where the hardness of the MR elastomer changes as a function of an applied magnetic field. MR elastomers have also been used to produce actuators. For example, magnetoactive soft materials (MSMs) have been used to implement robotic grippers and other mechanical elements.

BRIEF SUMMARY OF SOME EXAMPLES

The following presents a summary of one or more aspects of the present disclosure, in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated features of the disclosure and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects of the disclosure as a prelude to the more detailed description that is presented later.
An aspect of the subject matter described in this disclosure can be implemented by a system. The system can include a first electromagnet operable to pump a fluid through a first cavity of a flexible conduit by repeatedly compressing the first cavity in a first sequence, a second electromagnet operable to pump the fluid through a second cavity of the flexible conduit by repeatedly compressing the second cavity in a second sequence, and a third electromagnet operable to pump the fluid through a third cavity of the flexible conduit by repeatedly compressing the third cavity in a third sequence, wherein the first electromagnet compresses the first cavity by applying a first magnetic field to a magnetoactive elastomer, the second electromagnet compresses the second cavity by applying a second magnetic field to the magnetoactive elastomer, and the third electromagnet compresses the third cavity by applying a third magnetic field to the magnetoactive elastomer.
Another aspect of the subject matter described in this disclosure can be implemented by a system. The system can include a magnetoactive flexible conduit that includes a magnetoactive elastomer, wherein the magnetoactive flexible conduit is operable to constrict in response to a magnetic field.
Yet another aspect of the subject matter described in this disclosure can be implemented in a method. The method can include pumping a fluid through a first cavity of a flexible conduit by repeatedly applying a first magnetic field to a magnetoactive elastomer in a first sequence, pumping the fluid through a second cavity of the flexible conduit by repeatedly applying a second magnetic field to the magnetoactive elastomer in a second sequence, and pumping the fluid through a third cavity of the flexible conduit by repeatedly applying a third magnetic field to the magnetoactive elastomer in a third sequence, wherein the magnetoactive elastomer is operable to compress the flexible conduit in response to a magnetic field.
In some implementations of the methods and devices, the magnetoactive elastomer includes superparamagnetic nanoparticles embedded in a polymer matrix. In some implementations of the methods and devices, the devices can include an anvil, wherein the first electromagnet compresses the first cavity by compressing the magnetoactive elastomer against the anvil. In some implementations of the methods and devices, the devices can include a magnetoactive anvil that is formed from the magnetoactive elastomer and is operable to compress the flexible conduit against the anvil. In some implementations of the methods and devices, the devices can include the flexible conduit, wherein the flexible conduit is a magnetoactive flexible conduit formed from the magnetoactive elastomer, is operable to constrict in response to a magnetic field, and is operable to compress against the anvil in response to a magnetic field. In some implementations of the methods and devices the flexible conduit is formed from the magnetoactive elastomer and is operable to constrict in response to a magnetic field.
In some implementations of the methods and devices the flexible conduit includes a first magnetoactive section and a second magnetoactive section that are formed from the magnetoactive elastomer, the flexible conduit includes an inactive section between the first magnetoactive section and the second magnetoactive section, and the first magnetoactive section and the second magnetoactive section are operable to constrict in response to a magnetic field. In some implementations of the methods and devices the first sequence is a two-phase sequence that includes a first cavity filling phase and a first cavity emptying phase, the second sequence includes a second cavity filling phase and a second cavity emptying phase that pushes the fluid into the first cavity, and the second cavity emptying phase coincides at least in part with the first cavity filling phase. In some implementations of the methods and devices the second sequence further includes a second cavity full phase, a second cavity empty phase that prevents the fluid from flowing into the second cavity, and the second cavity full phase and the second cavity emptying phase coincide with the first cavity filling phase. In some implementations of the methods and devices, the devices can include a pump controller operatively coupled to the first electromagnet, the second electromagnet, and the third electromagnet, wherein the pump controller is operable to control the first magnetic field, the second magnetic field, and the third magnetic field.
In some implementations of the methods and devices, the magnetoactive elastomer includes superparamagnetic nanoparticles embedded in a polymer matrix. In some implementations of the methods and devices, the device further includes a first electromagnet operable to pump a fluid through a first cavity of the magnetoactive flexible conduit by applying a first magnetic field to the first cavity in a first sequence, and a second electromagnet operable to pump the fluid through a second cavity of the magnetoactive flexible conduit by applying a second magnetic field to the second cavity in a second sequence. In some implementations of the methods and devices, the device further includes an anvil, and a magnetoactive anvil that includes additional magnetoactive elastomer and is operable to compress the magnetoactive flexible conduit against the anvil in response to a magnetic field, wherein the first cavity is compressed at least in part by the magnetoactive anvil and the first magnetic field.
In some implementations of the methods and devices, the magnetoactive elastomer includes superparamagnetic nanoparticles embedded in a polymer matrix. In some implementations of the methods and devices, the first magnetic field compresses the first cavity by compressing the magnetoactive elastomer against an anvil. In some implementations of the methods and devices, a magnetoactive anvil that is formed from the magnetoactive elastomer compresses the flexible conduit against the anvil. In some implementations of the methods and devices, the flexible conduit includes the magnetoactive elastomer and is operable to constrict in response to a magnetic field. In some implementations of the methods and devices, the flexible conduit includes a first section that is formed from the magnetoactive elastomer and is operable to constrict in response to the first magnetic field.
These and other aspects will become more fully understood upon a review of the detailed description, which follows. Other aspects and features will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific examples in conjunction with the accompanying figures. While features may be discussed relative to certain examples and figures below, any example may include one or more of the advantageous features discussed herein. In other words, while one or more examples may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various examples discussed herein. In similar fashion, while the examples may be discussed below as devices, systems, or methods, the examples may be implemented in various devices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a high-level conceptual diagram illustrating an example of a MSM peristaltic pump, according to some aspects.

FIG. 2 is a high-level flow diagram illustrating an example of sequences of pumping phases that may be used by the MSM peristaltic pump shown in FIG. 1 , according to some aspects.

FIG. 3 is a high-level conceptual diagram illustrating a MSM anvil compressing a flexible conduit, according to some aspects.

FIG. 4 is a high-level conceptual diagram illustrating MSM flexible conduits that have been closed by the magnetic field produced by an electromagnet, according to some aspects.

FIG. 5 is a high level conceptual diagram illustrating a flexible conduit with magnetoactive sections, according to some aspects.

FIG. 6 is a high level conceptual diagram illustrating a flexible conduit with a magnetoactive strip, according to some aspects.

FIG. 7 is a high level conceptual diagram illustrating a microfluidic device that can pump a fluid through a channel, according to some aspects.

FIG. 8 is a high level flow diagram illustrating a method for using magnetoactive elastomer to pump a fluid, according to some aspects.

Throughout the description, similar reference numbers may be used to identify similar elements.

DETAILED DESCRIPTION

It will be readily understood that the components of the examples as generally described herein and illustrated in the appended figures could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of various examples, as represented in the figures, is not intended to limit the scope of the present disclosure, but is merely representative of various examples. While the various aspects of the examples are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.
Systems and methods that implement aspects may have various differing forms. The described systems and methods are to be considered in all respects only as illustrative and not restrictive. The scope of the claims is, therefore, indicated by the claims themselves rather than by this detailed description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Reference throughout this specification to features, advantages, or similar language does not imply that any system or method implements each and every aspect that may be realized. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in an example may be implemented in or by at least one example. Thus, discussions of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same example.
Furthermore, the described features, advantages, characteristics, and aspects may be combined in any suitable manner in one or more systems or methods. One skilled in the relevant art will recognize, in light of the description herein, that one example may be practiced without one or more of the specific features or advantages of another example. In other instances, additional features and advantages may be recognized in one example that may not be present in all the examples.
Reference throughout this specification to “one example”, “an example”, or similar language means that a particular feature, structure, or characteristic described in connection with the indicated example is included in at least one example. Thus, the phrases “in one example”, “in an example”, and similar language throughout this specification may, but do not necessarily, all refer to the same example.
MSM material is a magnetoactive material that may be used for implementing actuators and elements in macro-fluidic and micro-fluidic devices. A MSM based peristaltic pump is an example of a device in which MSM materials perform pumping actions and valving actions that in the past have been performed by pistons. Prior linear peristaltic pumps utilize pistons (often called fingers), commonly 8 to 14 pistons, that can compress a flexible conduit against an anvil (e.g., a steel plate, plastic block, etc.). A section of flexible conduit that is between a piston and the anvil may be referred to as a cavity. During a cavity emptying phase, the piston may compress the flexible conduit by pressing the flexible conduit against the anvil until all the fluid has been forced from the cavity. During a cavity filling phase, the piston may release the flexible conduit by moving away from the anvil until the cavity has filled with fluid. Some peristaltic pumps actuate the pistons in a wave-like pattern to thereby move an occlusion zone along the flexible conduit and create a pulsating flow. The occlusion zone includes numerous contiguous cavities (e.g., ten contiguous cavities). An aspect of the piston driven pumps is that the piston's travel must be calibrated to match the flexible conduit. Too little travel may fail to fully compress the cavity resulting in inefficiency and may even allow fluid to flow backward. Too much travel may crush the flexible conduit against the anvil such that the flexible conduit breaks or is permanently deformed. A cavity in a permanently deformed flexible conduit may remain closed regardless of piston position or may fail to fully reopen.
Pumps implemented with MSM materials are less likely to damage the flexible conduit. In a macro-fluidic application, a MSM material may be used as the flexible conduit or as a soft anvil of a peristaltic pump. A soft anvil, also referred to as a MSM anvil, may replace the pistons such that the flexible conduit may be positioned between the anvil and the soft anvil. The soft anvil may compress the flexible conduit against the anvil. The magnetic fields produced by electromagnets can pull sections of the MSM anvil to the anvil to thereby compress the flexible conduit and close the cavities much as a piston would but without the danger of crushing the flexible conduit. A MSM flexible conduit may be used in which the magnetic fields produced by electromagnets close sections of the MSM flexible conduit. In one such example, the MSM flexible conduit may be a shape memory type MSM structure that transitions between open and closed based on an applied magnetic field. In such an example, no anvil is needed because the MSM flexible conduit itself changes shape due to the applied magnetic fields. In another example, the magnetic field may pull the MSM flexible conduit into a anvil to thereby compress the cavities. Those practiced in MR elastomers and MSM materials are familiar with shape memory type MSM structures.
In a macro-fluidic application, flexible conduits (including MSM flexible conduits) may be consumable items that are regularly discarded and new flexible conduits regularly installed in the pump. In a microfluidic application, the entire pump may be a consumable item with fluid channels formed from MSM material and from other materials that are not magnetic, ferromagnetic, or superparamagnetic. For example, a fluid channel in a micro-fluidic device may be formed of a MSM material such that applied magnetic fields may cause the fluid channel to pump fluid. In another example, a strip of material along the fluid channel may be a MSM material forming a soft anvil that moves under the influence of a magnetic field. In some examples, the MSM flexible conduit may be fully open in the absence of a magnetic field such that applying a magnetic field causes the cavity to close. In other examples, the MSM conduit may be fully closed in the absence of a magnetic field such that applying a magnetic field causes the cavity to open.
A magnetoactive anvil or a magnetoactive flexible conduit may be formed with a material that has superparamagnetic (SPNP) nanoparticles embedded in a polymer. For example, SPNP nanoparticles may be admixed in a silicone monomer prior to polymerization that, when polymerized, forms a magnetoactive element. Superparamagnetism is a phenomenon that can occur in very small ferromagnetic (e.g., 10-150 nm iron oxide nanoparticles) or ferrimagnetic nanoparticles. In an example, a magnetoactive element may be formed with SPNP nanoparticles such that the magnetoactive element does not retain a magnetic field after an external magnetic field is removed. This property may be beneficial for a fluid pump because it may prevent some material (e.g., enzymes tagged with SPNP nanoparticles) from clumping to or near the magnetoactive element.
Those practiced in actuators and controllers for actuators are familiar with dynamically controlling magnetic fields. For example, electric motors, including stepper motors and servo motors, may be controlled by motor controllers that control the electric current flowing through the windings of the motor's electromagnets. Similarly, solenoids may be controlled by controlling the electric current flowing through the windings of the solenoid's electromagnet. As such, those practiced in the art of mechanical controls are familiar with techniques and methods that, in light of the teachings herein, may be used for controlling the MSM actuators of a pump such as the peristaltic pump discussed herein.
FIG. 1 is a high-level conceptual diagram illustrating an example of a MSM peristaltic pump 100, according to some aspects. A MSM peristaltic pump 100 may pump fluid by compressing cavities in a magnetoactive flexible conduit 116 in a wave like sequence similar to the wavelike sequence currently used by many cam driving peristaltic pumps. Such pumps produce a pulsating fluid flow. A MSM peristaltic pump 100 may produce a nearly pulse free and even fluid flow by compressing cavities through multistage sequences. In one example, the MSM peristaltic pump 100 has five cavities with the cavity nearest the pump output moving through a two-phase sequence while the other cavities move through four-phase sequences. The two-phase sequence includes a cavity filling phase and a cavity emptying phase. The four-phase sequences include a cavity filling phase, a cavity full phase, a cavity emptying phase, and a cavity empty phase. A magnetic field may cause a cavity to close during a cavity emptying phase to thereby force fluid out of the cavity until the cavity is empty. The magnetic field can hold the flexible conduit completely closed during the cavity empty phase to keep the cavity empty and to prevent fluid from flowing through the cavity. The magnetic field may be removed or relaxed during the cavity filling phase, thereby allowing the flexible conduit to open and fill. The cavity can stay open and full during the cavity full phase.
The magnetic fields may be individually controlled to thereby coordinate the opening and closing of the cavities. An electromagnet may produce a magnetic field that acts on a length of magnetoactive material such as a MSM anvil or a MSM flexible conduit. A cavity is a length of flexible conduit that is acted on directly or indirectly by the magnetic field produced by one of the pump's electromagnets. The magnetic field can act directly on a magnetoactive flexible conduit such as a MSM flexible conduit because the magnetoactive flexible conduit itself is magnetoactive. Similarly, the magnetic field may act directly on a magnetoactive anvil such as a MSM anvil because the magnetoactive anvil itself is magnetoactive. The magnetic field may act indirectly on a flexible conduit that is positioned between a magnetoactive anvil and an anvil (e.g., a hard plastic surface that is not magnetoactive).
The MSM peristaltic pump 100 may include a pump controller 106, electromagnets 111-115, an anvil 110, a pump input 118, and a pump output 117. A magnetoactive flexible conduit 116 is installed in the MSM peristaltic pump 100 over the anvil 110. The anvil supports the magnetoactive flexible conduit such that the magnetic fields produced by the electromagnets can compress the magnetoactive flexible conduit by pulling the magnetoactive flexible conduit against the anvil. A fluid 119 flowing through the magnetoactive flexible conduit 116 can flow into the MSM peristaltic pump 100 via the pump input 118 and can flow out of the MSM peristaltic pump 100 via the pump output 117. The pump controller 106 is operatively coupled to the electromagnets and may control the strengths and directions of the magnetic fields to thereby open and close the cavities. The pump controller 106 may be or may include a computer that includes a processor 127 and a memory 126. A computer may be operable to control driver circuits powering the electromagnets to thereby control the magnetic fields as is notoriously well known. The pump controller may therefore be implemented using such a computer and such driver circuits. The pump controller 106 can include a field sequencer 107, and a memory 126 operable to store executable code 128. The executable code 128 (e.g., compiled or interpreted computer programs) may be executed by the processor 127 to thereby implement aspects of the field sequencer 107. The field sequencer controls and coordinates the directions and strengths of the magnetic fields produced by the electromagnets to thereby drive the cavities through multi-phase sequences. It is by driving the cavities through the multi-phase sequences that the fluid 119 is pumped through the MSM peristaltic pump 100.
The electromagnets include a first electromagnet 111 a second electromagnet 112, a third electromagnet 113, a fourth electromagnet 114, and a fifth electromagnet 115. The magnetic fields produced by the electromagnets define cavities in the magnetoactive flexible conduit 116. The cavities include a first cavity 131, a second cavity 132, a third cavity 133, a fourth cavity 134, and a fifth cavity 135. The first cavity 131 in the magnetoactive flexible conduit 116 is next to a pole of the first electromagnet 111. The second cavity 132 in the magnetoactive flexible conduit 116 is next to a pole of the second electromagnet 112. The third cavity 133 in the magnetoactive flexible conduit 116 is next to a pole of the third electromagnet 113. The fourth cavity 134 in the magnetoactive flexible conduit 116 is next to a pole of the fourth electromagnet 114. The fifth cavity 135 in the magnetoactive flexible conduit 116 is next to a pole of the fifth electromagnet 115.
FIG. 2 is a high-level flow diagram illustrating an example of sequences 201-205 of pumping phases that may be used by the MSM peristaltic pump shown in FIG. 1 , according to some aspects. The sequences illustrated in FIG. 2 may be used to drive the electromagnets 111-115 to produce a fluid flow that is completely or nearly pulse free. The sequences include a first sequence 201 for the first electromagnet 111, a second sequence 202 for the second electromagnet 112, a third sequence 203 for the third electromagnet 113, a fourth sequence 204 for the fourth electromagnet 114, and a fifth sequence 205 for the fifth electromagnet 115. The first sequence 201 is a two-phase sequence in which the first electromagnet 111 repeatedly moves from a first cavity filling phase 211 to a first cavity emptying phase 212. The second sequence 202 is a four-phase sequence in which the second electromagnet 112 repeatedly moves from a second cavity full phase 221 to a second cavity emptying phase 222 to a second cavity empty phase 223 to a second cavity filling phase 224. The third sequence 203 is a four-phase sequence in which the third electromagnet 113 repeatedly moves from a third cavity emptying phase 231 to a third cavity empty phase 232 to a third cavity filling phase 233 to a third cavity full phase 234. The fourth sequence 204 is a four-phase sequence in which the fourth electromagnet 114 repeatedly moves from a fourth cavity empty phase 241 to a fourth cavity filling phase 242 to a fourth cavity full phase 243 to a fourth cavity emptying phase 244. The fifth sequence 205 is a four-phase sequence in which the fifth electromagnet 115 repeatedly moves from a fifth cavity filling phase 251 to a fifth cavity full phase 252 to a fifth cavity emptying phase 253 to a fifth cavity empty phase 254.
Let D be the desired rate at which fluid flows from the pump. The pump can produce a fluid flow at the desired rate, D, by coordinating the sequences through which the electromagnets are moved. As such, specific phases of each sequence may coincide with specific phases of the other sequences. Coincide means “occur at or during the same time”. Observing the first sequence, it is seen that the first cavity is filling during the first cavity filling phase 211. In order to maintain the desired out flow, fluid must be pumped into the first cavity at a rate equaling D plus the rate required to fill the first cavity during the first cavity filling phase. As such, the first half of the first cavity filling phase 211 a can coincide with the second cavity full phase 221, the third cavity emptying phase 231, the fourth cavity empty phase 241, and the fifth cavity filling phase 251. Fluid is pushed out of the third cavity at a rate of 2D while the fourth cavity is held closed (cavities in the “empty” phase are held closed which prevents fluid from flowing through or past the cavity) and the second cavity is full. The result is that the third electromagnet is pumping fluid into the first cavity and out of the pump such that the first cavity fills and the pump's output flow remains steady. Holding the fourth cavity closed ensures that the fluid is pumped from the third cavity toward the pump output. The fifth cavity may be allowed to fill during the first cavity filling phase while the fourth cavity is held closed. If the third cavity is the same size as the first cavity, as in the illustrated example, then the third cavity is emptied halfway through the first cavity filling phase.
The second half of the first cavity filling phase 211 b can coincide with the second cavity emptying phase 222, the third cavity empty phase 232, the fourth cavity filling phase 242, and the fifth cavity full phase 252. Fluid is pushed out of the second cavity at a rate of 2D while the third cavity is held closed which prevents fluid from flowing into or past the third cavity. The result is that the second electromagnet is pumping fluid into the first cavity and out of the pump such that the first cavity fills and the pump's output flow remains steady. If the second cavity is the same size as the first cavity, as in the illustrated example, then the second cavity is emptied when the first cavity filling phase completes. The fourth cavity may be allowed to fill during the first cavity filling phase while the third cavity is held closed and while the fifth cavity is full or filling.
The first cavity is full and the second cavity is held closed at the end of the first cavity filling phase. The pump's output flow may therefore be maintained by pumping fluid out of the first cavity while the closed second cavity prevents back flow. The first half of the first cavity emptying phase 212 a can coincide with the second cavity empty phase 223, the third cavity filling phase 233, the fourth cavity full phase 243, and the fifth cavity emptying phase 253. The third cavity is allowed to fill during the first half of the first cavity emptying phase such that the third cavity is full when the next first cavity emptying phase begins. The fifth cavity is emptied during the first half of the first cavity emptying phase to pump fluid into the third cavity and to prevent backflow during the second half of the first cavity emptying phase. The desired outflow could be maintained until the end of the first cavity emptying phase by completely emptying the first cavity while holding the second cavity closed. However, the subsequent first cavity filling phase must begin with the second cavity full. The second cavity must therefore be filled during the second half of the first cavity emptying phase.
The second half of the first cavity emptying phase 212 b can coincide with the second cavity filling phase 224, the third cavity full phase 234, the fourth cavity emptying phase 244, and the fifth cavity empty phase 254. The fifth cavity is held closed to prevent backflow while the fourth cavity is emptied to thereby fill the second cavity. The second cavity is full, the third cavity is full, and the fourth cavity is held closed at the end of the first cavity filling phase. The pump is therefore ready for the next first cavity filling phase.
FIG. 3 is a high-level conceptual diagram illustrating a MSM anvil 301 compressing a flexible conduit 302, according to some aspects. A magnetoactive element, such as the MSM anvil 301, can be formed from an elastomer that has magnetic nanoparticles (e.g., SPNP iron oxide crystals) embedded within its polymer matrix. An elastomer is a polymer material that displays elastic properties, like natural rubber, such as regaining its original shape when a load is removed from the material. An element formed from an elastomer can have a relaxed shape and a deformed shape. The relaxed shape is the shape that the element takes when it is not subjected to outside forces. The deformed shape is a shape that the element takes when subjected to an outside force. For example, a flexible conduit may be a tube of elastomer that has a relaxed shape with a circular cross section such that fluid may flow through the tube. An outside force may compress the tube into a deformed shape that does not allow fluid to flow through the tube. An electromagnet 303 can produce a magnetic field 304 that pulls a section of the MSM anvil 301 toward the electromagnet 303. The MSM anvil 301 can compress a flexible conduit 302 that is positioned between the electromagnet when the magnetic field 304 forces the MSM anvil 301 moving toward the electromagnet. The exemplary pump illustrated in FIG. 1 is illustrated with a magnetoactive flexible conduit. A different example may have one or more magnetoactive anvil 301 positioned to compress the flexible conduit. The magnetic fields produced by the electromagnets 111-115 may therefore compress and release the cavities by pulling sections of the magnetoactive anvil toward the anvil 110. Reversing the polarity of the electromagnet may push the magnetoactive anvil 301 away from the electromagnet which may allow the flexible conduit to return to its relaxed shape more rapidly. In some examples, elements with SPNP nanoparticles may always be attracted to the electromagnet regardless of the polarity of the magnetic field.
FIG. 4 is a high-level conceptual diagram illustrating MSM flexible conduits that have been closed by the magnetic field produced by an electromagnet, according to some aspects. The upper flexible conduit 401 is a magnetoactive flexible conduit in which the entire flexible conduit is drawn toward the electromagnet 303 by the magnetic field 402 to thereby compress the magnetoactive flexible conduit and close the cavity that is above the electromagnet 303. Reversing the polarity of the electromagnet may push the magnetoactive flexible conduit open. In another example, the relaxed shape of the flexible conduit may be flat such that the cavity is opened by the magnetic field.
The lower flexible conduit 403 is a magnetoactive flexible conduit in which the magnetic field 402 pushes the side nearest the electromagnet away from the electromagnet 303 and pulls the side farthest from the electromagnet toward the electromagnet 303. As such, the magnetic field causes the magnetoactive flexible conduit to constrict because the opposite sides move toward one another. Such an action may be produced by a flexible conduit having differently aligned magnetic domains on the opposite sides. In another example, multiple electromagnets or a ring shaped electromagnet (the flexible conduit passing through the hole in the ring) may produce magnetic fields that cause the magnetoactive flexible conduit to constrict. In some examples, reversing the magnetic field may push the magnetoactive flexible conduit open. The exemplary pump illustrated in FIG. 1 is illustrated with a magnetoactive flexible conduit such as the upper flexible conduit. Note that an example without an anvil may compress the flexible conduit directly against the electromagnets 111-115. A different example may have a magnetoactive flexible conduit such as the lower flexible conduit 403 positioned such that the magnetic fields produced by the electromagnets 111-115 cause the flexible conduit to constrict. Such an example may have no need for an anvil.
FIG. 5 is a high level conceptual diagram illustrating a flexible conduit 500 with magnetoactive sections 503, according to some aspects. The flexible conduit includes magnetoactive sections 503 and inactive sections 502. The inactive sections 502 are not magnetoactive. The flexible conduit 500 may be formed by selectively embedding SPNP nanoparticles into sections of the flexible conduit 500. The magnetoactive sections 503 may form the cavities of a pump such as the peristaltic pump 100 illustrated in FIG. 1 .
FIG. 6 is a high level conceptual diagram illustrating a flexible conduit 600 with a magnetoactive strip 602, according to some aspects. The exemplary pump illustrated in FIG. 1 may use such a flexible conduit. For example, the flexible conduit may be installed such that the side of the conduit farthest from the electromagnets is the magnetoactive strip 602. The side closest to the electromagnet may be an inactive strip 603. The inactive strip may be formed from an elastomer that is not magnetoactive. In such an example the magnetic fields may pull and/or push only one side of the flexible conduit.
FIG. 7 is a high level conceptual diagram illustrating a microfluidic device 700 that can pump a fluid through a first channel 708, according to some aspects. The microfluidic device 700 can have a body 701 into which channels 708, 709 are formed and into which active elements, such as magnetoactive elements may be formed (e.g., via selective deposition of SPNP nanoparticles) or attached. A magnetoactive anvil 702 may be positioned in a cavity 703 along a first channel 708. Electromagnets 704, 705 may draw sections of the magnetoactive anvil 702 against an opposite wall 710 of the first channel 708. The electromagnets may be sequenced to thereby pump a fluid through the first channel 708. The fluid may enter the first channel 708 via a second channel 709. Activating an electromagnet 707 may pull a magnetoactive valve to thereby allow fluid to flow from the second channel 709 into the first channel 708. The magnetoactive valve 706 may be an elastomer with SPNP particles embedded in the polymer matrix. The example illustrated in FIG. 7 has a two cavity peristaltic pump. The two cavities may be opened and closed in sequences that may pump fluid in either direction within the first channel. Other examples may have more cavities such as a micro-fluidic version of the five cavity peristaltic pump illustrated in FIG. 1 .
FIG. 8 is a high level flow diagram illustrating a method 800 for using magnetoactive elastomer to pump a fluid, according to some aspects. At block 801, a fluid may be pumped through a third cavity of a flexible conduit by repeatedly applying a third magnetic field to a magnetoactive elastomer in a third sequence. At block 802, the fluid may be pumped through a second cavity of the flexible conduit by repeatedly applying a second magnetic field to the magnetoactive elastomer in a second sequence. At block 803, the fluid may be pumped through a first cavity of the flexible conduit by repeatedly applying a first magnetic field to the magnetoactive elastomer in a first sequence. The magnetoactive elastomer may be operable to compress the flexible conduit in response to a magnetic field. Pumping the fluid may require that the actions of blocks 801-803 be performed simultaneously.
Although the operations of the method(s) herein are shown and described in a particular order, the order of the operations of each method may be altered so that certain operations may be performed in an inverse order or so that certain operations may be performed, at least in part, concurrently with other operations. Instructions or sub-operations of distinct operations may be implemented in an intermittent and/or alternating manner.
It may also be noted that at least some of the operations for the methods described herein may be implemented using software instructions stored on a computer usable storage medium for execution by a computer. For example, a computer program product can include a computer usable storage medium to store a computer readable program.
Although specific examples have been described and illustrated, the scope of the claimed systems, methods, devices, etc. is not to be limited to the specific forms or arrangements of parts so described and illustrated. The scope may be defined by the claims appended hereto and their equivalents.

Claims

What is claimed is:

1. A system comprising:

a first electromagnet operable to pump a fluid through a first cavity of a flexible conduit by repeatedly compressing the first cavity in a first sequence;

a second electromagnet operable to pump the fluid through a second cavity of the flexible conduit by repeatedly compressing the second cavity in a second sequence; and

a third electromagnet operable to pump the fluid through a third cavity of the flexible conduit by repeatedly compressing the third cavity in a third sequence,

wherein:

the first electromagnet compresses the first cavity by applying a first magnetic field to a magnetoactive elastomer;

the second electromagnet compresses the second cavity by applying a second magnetic field to the magnetoactive elastomer; and

the third electromagnet compresses the third cavity by applying a third magnetic field to the magnetoactive elastomer.

2. The system of claim 1, wherein the magnetoactive elastomer includes superparamagnetic nanoparticles embedded in a polymer matrix.

3. The system of claim 1, further including:

an anvil,

wherein the first electromagnet compresses the first cavity by compressing the magnetoactive elastomer against the anvil.

4. The system of claim 3, further including:

a magnetoactive anvil that is formed from the magnetoactive elastomer and is operable to compress the flexible conduit against the anvil.

5. The system of claim 4, further including:

the flexible conduit,

wherein the flexible conduit is a magnetoactive flexible conduit formed from the magnetoactive elastomer, is operable to constrict in response to a magnetic field, and is operable to compress against the anvil in response to the magnetic field.

6. The system of claim 1, wherein:

the flexible conduit is formed from the magnetoactive elastomer and is operable to constrict in response to a magnetic field.

7. The system of claim 1, wherein:

the flexible conduit includes a first magnetoactive section and a second magnetoactive section that are formed from the magnetoactive elastomer;

the flexible conduit includes an inactive section between the first magnetoactive section and the second magnetoactive section; and

the first magnetoactive section and the second magnetoactive section are operable to constrict in response to a magnetic field.

8. The system of claim 1, wherein:

the first sequence is a two-phase sequence that includes a first cavity filling phase and a first cavity emptying phase;

the second sequence includes a second cavity filling phase and a second cavity emptying phase that pushes the fluid into the first cavity; and

the second cavity emptying phase coincides at least in part with the first cavity filling phase.

9. The system of claim 8, wherein:

the second sequence further includes a second cavity full phase, a second cavity empty phase that prevents the fluid from flowing into the second cavity; and

the second cavity full phase and the second cavity emptying phase coincide with the first cavity filling phase.

10. The system of claim 1, further including:

a pump controller operatively coupled to the first electromagnet, the second electromagnet, and the third electromagnet,

wherein the pump controller is operable to control the first magnetic field, the second magnetic field, and the third magnetic field.

11. A system comprising:

a magnetoactive flexible conduit that includes a magnetoactive elastomer,

wherein the magnetoactive flexible conduit is operable to constrict in response to a magnetic field.

12. The system of claim 11, wherein the magnetoactive elastomer includes superparamagnetic nanoparticles embedded in a polymer matrix.

13. The system of claim 11, further comprising:

a first electromagnet operable to pump a fluid through a first cavity of the magnetoactive flexible conduit by applying a first magnetic field to the first cavity in a first sequence; and

a second electromagnet operable to pump the fluid through a second cavity of the magnetoactive flexible conduit by applying a second magnetic field to the second cavity in a second sequence.

14. The system of claim 13, further including:

an anvil; and

a magnetoactive anvil that includes additional magnetoactive elastomer and is operable to compress the magnetoactive flexible conduit against the anvil in response to a magnetic field,

wherein the first cavity is compressed at least in part by the magnetoactive anvil and the first magnetic field.

15. A method comprising:

pumping a fluid through a first cavity of a flexible conduit by repeatedly applying a first magnetic field to a magnetoactive elastomer in a first sequence;

pumping the fluid through a second cavity of the flexible conduit by repeatedly applying a second magnetic field to the magnetoactive elastomer in a second sequence; and

pumping the fluid through a third cavity of the flexible conduit by repeatedly applying a third magnetic field to the magnetoactive elastomer in a third sequence,

wherein the magnetoactive elastomer is operable to compress the flexible conduit in response to a magnetic field.

16. The method of claim 15, wherein the magnetoactive elastomer includes superparamagnetic nanoparticles embedded in a polymer matrix.

17. The method of claim 15, wherein the first magnetic field compresses the first cavity by compressing the magnetoactive elastomer against an anvil.

18. The method of claim 17, wherein a magnetoactive anvil that is formed from the magnetoactive elastomer compresses the flexible conduit against the anvil.

19. The method of claim 15, wherein the flexible conduit includes the magnetoactive elastomer and is operable to constrict in response to a magnetic field.

20. The method of claim 15, wherein the flexible conduit includes a first section that is formed from the magnetoactive elastomer and is operable to constrict in response to the first magnetic field.