WO2016176132A1

WO2016176132A1 - Planar spring for fluid mover

Info

Publication number: WO2016176132A1
Application number: PCT/US2016/029111
Authority: WO
Inventors: Timothy Swain LUCAS
Original assignee: Aavid Thermalloy, Llc
Priority date: 2015-04-29
Filing date: 2016-04-25
Publication date: 2016-11-03

Abstract

A fluid mover includes a chamber with one or more outlet openings, first and/or second fluidic diaphragm(s) having a fluid-moving portion movable in the chamber to cause fluid to move at the outlet opening, and a coil assembly magnetically coupled to the fluidic diaphragm to move the movable portion of the fluidic diaphragm(s) in response to a current in the coil. A spring portion of the fluidic diaphragm(s) may be separate from the fluid-moving portion and be arranged to exert a spring bias on the fluid-moving portion. The spring portion may include two or more spring elements that each includes a chord portion and a radial portion. The chord portion may be attached to the chamber housing at opposite ends, and the radial portion may extend radially inward from the chord portion from an intermediate point between the opposite ends to a center of the diaphragm.

Description

PLANAR SPRING FOR FLUID MOVER

BACKGROUND OF THE INVENTION

1) Field of Invention

This invention relates generally to the pumping of fluids in positive displacement pumping devices, otherwise known as fluid movers, such as liquid pumps, gas compressors and synthetic jets and in general to the transfer of energy to fluids.

2) Description of Related Art

When compared to rotary, piston, centrifugal and other pumping approaches, mechanically resonant diaphragm architectures provide a lower profile means for creating a cyclic positive displacement for small fluid movers such as pumps, compressors and synthetic jets. One such fluid mover, i.e., synthetic jet devices, can provide significant energy savings when used for cooling high power density and high power dissipation electronics products such as for example servers, computers, routers, laptops, HBLED lighting, notebooks, tablets and military electronics. U.S. Patent 8272851 and PCT application WO2012/048179 describe various arrangements for synthetic jet systems and other fluid mover systems.

SUMMARY OF THE INVENTION

However, a synthetic jet device is typically quite small because the entire device must be sized to fit within a space-constrained product, such as a notebook computer or tablet, and these space constraints have driven complexities in design that prevent the synthetic jet device from operating in an optimal manner. For example, some synthetic jet devices incorporate a spring component that helps control movement of a diaphragm into the fluid control portion of the diaphragm itself. This arrangement can introduce complexities and performance constraints on the diaphragm, e.g., by requiring portions of the diaphragm to perform both spring -bias and fluid- moving functions. For example, some portions of a diaphragm may ideally be free to move axially for fluid moving purposes, but since the spring of the diaphragm must be attached to the diaphragm housing, at least a portion of the spring must be located in areas where the diaphragm ideally would have more freedom of movement if the spring portion could be omitted. In some cases, this may result in the diaphragm having less than optimal spring-bias characteristics or fluid-moving characteristics. Consequently, diaphragm designs that combine both fluid moving and spring functions into a single component are challenging.

For less space-constrained products, the design challenge can be reduced by separating the fluid moving and spring functions into two separate components. Aspects of the invention provide for spring bias and fluid moving aspects of a diaphragm to be physically separated from each other, yet coupled together to provide a diaphragm that has desired spring and fluid moving features. For example, in one embodiment, the diaphragm may include a fluid moving portion and a spring portion that are parallel to each other and connected only at a center of the diaphragm. As a result, the spring portion may be arranged in any suitable way to provide desired spring characteristics for the diaphragm, and the fluid-moving portion may be arranged to provide desired fluid- moving characteristics.

In accordance with an aspect of the invention, a fluid mover includes a housing defining a chamber with one or more outlet openings. The outlet openings may be arranged to emit or otherwise create a synthetic jet or other fluid flow. A first fluidic diaphragm may be located in the chamber and have a fluid-moving portion movable in the chamber to cause fluid to move at the outlet opening, and a spring portion coupled to the fluid moving portion to bias the fluid-moving portion to a starting or initial position. The fluid-moving portion and the spring portion may be separate from each other, e.g., the spring portion may be arranged on one side of the fluid-moving portion. The spring portion may include two or more spring elements, each spring element including a chord portion having an intermediate point between opposite ends that are attached to the housing. A radial portion may extend radially inwardly from the intermediate point toward a center of the spring portion where the radial portion is attached to the fluid- moving portion. A coil assembly may also be provided in the chamber and be positioned adjacent the first fluidic diaphragm and magnetically coupled to the fluid- moving portion to move the fluid-moving portion in the chamber in response to a current in the coil. In some embodiments, the spring portion may be positioned on a side of the fluid-moving portion opposite the coil, and the spring portion may be arranged to urge the fluid- moving portion to move to a starting or initial position when the fluid-moving portion is moved by the coil. Thus, the spring portion may provide a force that helps the fluid- moving portion to move in an oscillatory manner relative to the starting or initial position.

In some embodiments, the chord portion of one or more spring elements may be flat and have an arcuate shape with a concave side positioned closer to the radial portion or the center than a convex side. This arrangement may help the chord portion to twist or bend in response to axial movement of the center of the spring portion, thereby helping to reduce stresses in the spring element in a radial direction. Where the spring portion is flat, such stresses may be reduced in the plane of the spring. In other embodiments, the chord portion may have a straight shape, e.g., with straight sides that are parallel to each other.

The radial portion may be attached to the chord portion at a midpoint of the chord portion, i.e., the intermediate point may be at a midpoint between the opposite ends, or located at another place between the opposite ends of the chord portion. Also, in some embodiments, sections of the chord portion on opposite sides of the intermediate point may be symmetrical, e.g., similarly sized and/or shaped, but such symmetry is not required, particularly if the intermediate point is located away from a midpoint of the chord portion. In some cases, the chord portion and the radial portion may define a "T" shape or "Y" shape.

Similar to the chord portion, the radial portion may be arranged in different ways, e.g., to provide different biasing characteristics. For example, the radial portion may include a rectangular portion that extends along a radial line extending from the center, or the radial portion may taper in width such that the radial portion is wider at an inner section nearer the center than an outer section. Other configurations are possible, such as tapering of the radial portion so as to be wider toward a center of the spring portion, etc. Also, while the chord and radial portions are flat and have a constant thickness in many embodiments, this is not required and a thickness of the chord and radial portions may vary.

In some embodiments, the spring portion is planar, e.g., is formed from a flat sheet of metal, plastic or other suitable material. Similarly, the fluid-moving portion may be planar, and the fluid-moving portion and the spring portion may be arranged so as to be parallel to each other and fixed to the housing at their respective peripheries. The spring portion and the fluid-moving portion may be attached together only at the center of the spring portion and a center of the fluid-moving portion, e.g., by a stud, rivet or other connector so that the centers move together in the axial direction.

The fluid-moving portion may be arranged in different ways, and may be relatively freely movable in the axial direction at its center. For example, the fluid- moving portion may have a flat section in a central area that can move axially to move fluid in the chamber and at the outlet. This flat section may be stiff and help reduce energy losses during operation of the fluid mover. An outer periphery of the fluid- moving portion may include a compliant ring or annulus that provides a fluid seal between the flat section and the housing and allows the flat section to move relatively freely in the chamber.

The coil assembly may be arranged in different ways, and in one embodiment, the coil assembly includes a coil with an opening, and at least one of a plug in the opening or a support around a periphery of the coil arranged to support the coil in the chamber. The plug and/or the support may include a material with a relative magnetic permeability greater than one and is arranged such that magnetic field lines created by a current in the coil to cause movement of the fluid-moving portion pass through the plug and/or support. For example, a flat section or other component of the fluid-moving portion at a central area may include a magnetically permeable material, such as a steel disc that functions as an armature. A magnetic field created by the coil may exert a force on the steel disc to cause the fluid-moving portion to move axially, and against (or with) the bias of the spring portion.

The first fluidic diaphragm and the coil assembly may be arranged such that no portion of the fluidic diaphragm enters the opening of the coil during movement of the fluidic diaphragm. For example, a plug may completely occlude the opening of the coil and while the fluid-moving portion may move close to the plug, the fluid-moving portion may not enter the opening of the coil. In one embodiment, the support includes a plate that defines a hole at which the coil is supported by the support, e.g., the support may be immediately adjacent the periphery of the coil around the hole. The support, coil and plug may define a flat structure, e.g., to provide a relatively flat surface in the chamber across which fluid moved by the fluid-moving portion may flow. In some embodiments, the fluid mover may include two fluid-moving portions arranged so that the first fluidic diaphragm is positioned over a top of the coil, and a second fluidic diaphragm is positioned under a bottom of the coil. The coil may be arranged to remain stationary relative to the housing and move fluid-moving portions of the first and second fluidic diaphragms toward each other based on a current in windings of the coil. Movement of the fluid-moving portions away from the coil may be caused by the spring portions coupled to each fluid-moving portion. In such an arrangement, upper and lower gaps may be present between the fluid-moving portion of the first fluidic diaphragm and the coil assembly, and between the fluid-moving portion of the second fluidic diaphragm and the coil assembly, respectively, and fluid may be moved in the upper and lower gaps based on movement of the fluid-moving portion of the first and second fluidic diaphragms relative to the housing. The fluid-moving portion of the fluidic diaphragm(s) may be arranged for vibratory movement in the chamber in which a portion of the fluid-moving portion moves at a frequency of 0.1 Hz to 1kHz or more.

These and other aspects of the invention will be apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part of the specification, illustrate select embodiments of the present invention and, together with the description, serve to explain the principles of the inventions. In the drawings:

FIG. 1 shows a perspective view of a fluid mover in an illustrative embodiment;

FIG. 2 shows a sectional view of the fluid mover along the line 2-2 in FIG. 1 ;

FIG. 3 shows a top view of a spring portion in an illustrative embodiment;

FIG. 4 shows the spring portion of FIG. 3 in which the center is axially displaced; FIG. 5 shows the FIG. 4 arrangement in side view;

FIG. 6 shows another embodiment of a spring portion; and

FIG. 7 shows yet another embodiment of a spring portion.

DETAILED DESCRIPTION

Aspects of the invention are not limited in application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. Other embodiments may be employed and aspects of the invention may be practiced or be carried out in various ways. Also, aspects of the invention may be used alone or in any suitable combination with each other. Thus, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

FIGs. 1 and 2 show a perspective, schematic view and a sectional view of a fluid mover 4, respectively, in an illustrative embodiment that includes a housing 1 that defines a chamber 6 having an internal volume in which first and second diaphragms 2a, 2b and a coil assembly 12 are located. (Note that top and bottom panels of the housing 1 are removed in FIG. 2 for clarity.) In this embodiment, the internal volume of the chamber 6 is divided into three main sections: a first outer chamber 6a located above the first diaphragm 2a, a central chamber 6b located between the first and second diaphragms 2a, 2b, and a second outer chamber 6c located below the second diaphragm 2b. While in this embodiment, the sections of the chamber 6 where the diaphragms 2 are located are circular in cross section, other shapes are possible. The central chamber 6b is divided into first and second gaps 25, 26 by the coil assembly 12. The first and second outer chambers 6a, 6c and the central chamber 6b are isolated from each other in the chamber 6 by the diaphragms 2, and communicate with an outlet opening 8 located at one side of the chamber 6. In this embodiment, each of the first and second outer chambers 6a, 6b and the central chamber 6b communicate with separate sections of the outlet, i.e., 8a, 8c and 8b, respectively The outlet opening 8 may be located in other places, such as at a top or bottom of the chamber 6, if desired, and in some embodiments such as liquid pumps and gas compressors, two or more openings 8 may be provided and these openings may also include valves to enable fluid compression and/or one- directional flow.

As is described in more detail below, the diaphragms 2a, 2b are controllable to move cyclically in the chamber 6 so that air or other fluid is alternately drawn into the first and second outer chambers 6a, 6c and the central chamber 6b at the respective opening sections 8a, 8b, 8c and then driven out of the opening section 8a, 8b, 8c in the direction of an arrow 10. As is known to those of skill in the art and described in more detail in U.S. Patent 8272851, this air movement at the outlet opening 8 can cause the formation of a series of air pulses and vortices that move away from the opening 8 in the direction of the arrow 10 so that a synthetic jet is created. In this embodiment, the fluid mover 4 includes an outlet nozzle or manifold 7 that is mated to the housing 1 at the outlet opening 8. The outlet nozzle 7 can be arranged to control a flow rate, direction of flow, location of flow and/or other characteristics of flow from the fluid mover 4. For example, in this embodiment, the outlet nozzle 7 includes three rows of openings 71 that are arranged to direct flow from each of the outlet opening sections 8a, 8b, 8c, respectively. That is, each row of nozzle openings 71 corresponds to a respective outlet section 8a, 8b, 8c and respective chamber section 6a, 6b, 6c, and each row of nozzle openings 71 is arranged to form a plurality of synthetic jets, with each jet being formed by a respective opening 71. It should be appreciated, however, that other arrangements for the outlet nozzle or manifold 7 are possible, such as routing flow in other directions or into one or more air flow ducts, using various port geometries such as a single slotted port instead of a row of round port openings, and so on.

In this embodiment, the coil assembly 12 includes a support 21, a coil 22 and a plug 23. The support 21 is arranged to support the coil 22 and the plug 23 in the chamber 6, e.g., such that the support 21, coil 22 and plug 23 remain stationary relative to the housing 1. The coil 22 is magnetically coupled to the diaphragms 2a, 2b so that a current in the coil 22 can cause movement of a portion of the diaphragms 2a, 2b. That is, a current in the coil 22 may create a magnetic field that generates an attractive force on the diaphragms 2a, 2b that causes the diaphragms 2a, 2b to move toward the coil assembly 12. This movement of the diaphragms 2a, 2b causes flow to occur in the first and second outer chambers 6a, 6c and the central chamber 6b (by adjusting a volume of the chambers 6a-6c), and correspondingly at the outlet opening sections 8a, 8b, 8c. The support 21 and/or plug 23 may have high relative magnetic permeability, e.g., a relative magnetic permeability greater than one, which may increase the magnetic forces of the coil's magnetic field on the diaphragm(s) 2.

Operation of the coil assembly 12 may be controlled by a controller 14 (e.g., including a suitably programmed general purpose computer or other data processing device) that receives control information (e.g., from one or more sensors, user input devices, etc.) and correspondingly controls operation of the coil assembly 12 and/or other fluid mover components. The controller 14 may include any suitable components to perform desired control, communication and/or other functions. For example, the controller 14 may include control circuitry such as one or more general purpose computers, a network of computers, one or more microprocessors or PICs, etc., for performing data processing functions, one or more memories for storing data and/or operating instructions (e.g., including volatile and/or non-volatile memories such as optical disks and disk drives, semiconductor memory, magnetic tape or disk memories, and so on), communication buses or other communication devices for wired or wireless communication (e.g., including various wires, switches, connectors, Ethernet communication devices, WLAN communication devices, and so on), software or other computer-executable instructions (e.g., including instructions for carrying out functions related to controlling the fluid mover 4, and other components), a power supply or other power source (such as a plug for mating with an electrical outlet, batteries, transformers, etc.), relays, other switching devices and/or drive circuitry for driving the coil assembly 12, mechanical linkages, one or more sensors or data input devices (such as a sensor to detect movement and/or position of the diaphragms 2a, 2b and/or temperature of a device being cooled by a jet stream created by the fluid mover 4, user-operated buttons or switches, an interface to receive control instructions from another device, and so on), user data input devices (such as buttons, dials, knobs, a keyboard, a touch screen or other), information display devices (such as an LCD display, indicator lights, a printer, etc.), and/or other components for providing desired input/output and control functions. In short, the controller 14 may include any suitable components to perform desired control and communication functions for the fluid mover 4 or for other fluid movers such as liquid pumps, gas compressors or acoustic pumps and compressors.

In accordance with an aspect of the invention, the diaphragms 2 each include a fluid moving portion 12 and a spring portion 13. Motion of the fluid moving portion 12 causes fluid movement in the chambers 6a and 6c, or 6b and 6c, and the spring portion 13 provides an axial spring bias to the fluid moving portion 12 to urge a center of the fluid moving portion 12 to move to a rest or initial position. The fluid moving portion 12 and the spring portion 13 are coupled together at a center of the diaphragm 2 via a connector 15, such as a rivet, stud or other fastener. Thus, as the coil 22 causes the diaphragms 2 to move, both the fluid moving portion 12 and the spring portion 13 move together at the connector 15. Outer portions of the fluid moving portion 12 and the spring portion 13 are fixed to the housing 1. In this embodiment, the housing has multiple layers that are stacked together and sandwich portions of the fluid moving portions 12 and the spring portions 13, but other configurations are possible. The fluid moving portion 12 of the diaphragms 2 includes a magnetically permeable or magnetic material such that a magnetic field generated by the coil 22 will create a magnetic force causing movement of the fluid moving portion 12. In this illustrative embodiment, the fluid moving portions 12 each include an armature 31 provided as a circular, flat plate on a side of the fluid moving portion 12 adjacent the coil 22 such that the plate is opposed to the coil assembly 12. The armature 31 is made of a steel with high magnetic permeability and has a thickness of about 0.010 inches in this embodiment, but other arrangements are possible. The fluid moving portions 12 may include other components that are attached to, and move with, the armature 31 and pneumatically separate opposite sides of the fluid moving portion 12 from each other. For example, the fluid moving portion 12 may include a gasket 32 that provides a pneumatic seal between the armature 31 and the housing 1. Of course, other arrangements are possible, such as having the armature 31 extend to the housing 1 , but have slots or other removed sections of the armature 31 to allow for relatively free movement of the armature 31 in a central region. A gasket 32 may be overmolded or otherwise arranged to seal slots or other openings in the armature 31. In another embodiment, the gasket 32 may be arranged as an elastomeric sheet that extends across the opening defined by the housing 1. An armature 31, e.g., including a disc of metal, may be molded within or otherwise attached to the elastomeric sheet. Other configurations are possible, as will be understood by those of skill in the art.

As noted above, the fluid moving portion 12 need not necessarily have spring characteristics that tend to urge the fluid moving portion 12 to an initial or starting position about which the fluid moving portion 12 is vibrated to cause fluid movement. This is because the spring portion 13 may provide a desired spring force on the fluid moving portion 12 in an axial direction, i.e., the direction of vibration of the fluid moving portion 12. As can be seen in FIG. 2, the fluid moving portion 12 and the spring portion 13 may be parallel to each other, e.g., may be planar structures that are spaced apart from each other.

In accordance with an aspect of the invention, the spring portion 13 includes two or more spring elements that each includes a chord portion and a radial portion. The chord portion is attached to the housing at opposite ends, and the radial portion extends radially inward from the chord portion from an intermediate point between the opposite ends to a center of the diaphragm. The intermediate point may be at a midpoint between the opposite ends, or positioned at another location between the ends. At the center, the radial portion attaches to the fluid moving portion 12 via the connector 15. This arrangement allows the spring portion to provide a relatively robust axial spring force on the fluid moving portion 12 via the connector 15, while minimizing stress in the radial direction on the spring portion. For example, the intermediate portion may be capable of movement in both axial and radial directions that would not be possible otherwise.

FIG. 3 shows an illustrative embodiment of a spring portion 13 that may be used in the embodiment of FIGs. 1 and 2. This embodiment includes four spring elements 17 that each includes a chord portion 14 and a radial portion 16 that extends radially inwardly from the chord portion 14 at an intermediate point 20 of the chord portion 14 to a center 27 of the spring portion 13. A dashed line 18 shows where the spring portion 13 is secured to the housing 1, and the chord portions 14 are effectively attached to the housing 1 via opposite ends 19. (The dashed line 18 could be moved radially inwardly, e.g., so as to be close to, but not at, the chord portions 14.) This configuration of the spring elements 17 allows the center 27 of the spring portion 13 to move axially without the spring portion 13 experiencing extreme stress in the radial direction as would be the case if the spring portion 13 were arranged as a solid sheet. That is, as the center 27 moves axially (in a direction perpendicular to the plane of FIG. 3), the intermediate point 20 may move both axially and radially inwardly due to twisting of the chord portions 14, e.g., at or near the ends 19 or also along the length of the chord portions 14. FIGs. 4 and 5 shows perspective and side views, respectively of the FIG. 3 spring portion 13 with the center 27 moved axially upward from a rest or starting position. As can be seen, the intermediate point 20 can move axially upwardly and radially inwardly with axial movement of the center 27. The spring elements 17 of the spring portion 13 are not limited to the arrangement of FIG. 3, and FIGs. 6 and 7 show alternate embodiments. FIG. 6 shows a spring portion 13 with four spring elements 17 arranged similarly to that in FIG. 3. However, whereas the chord portions 14 have an arcuate shape in FIG. 3 with a concave side nearer the center 27 than a convex side, the chord portions 14 in FIG. 6 have a straight shape, giving the spring elements 17 an overall "T" like shape. Also, the radial portions 16 in FIG. 3 taper in width such that an inner part of the radial portions 16 is wider than an outer part. However, in FIG. 6, the radial portions 16 do not taper in width. FIG. 7 shows another embodiment of a spring portion 13 that includes five spring elements 17. This arrangement has arcuately shaped chord portions 14, but radial portions 16 are not tapered in width as in FIG. 3. The openings positioned radially outboard of the chord portions 14 have an arcuate shape as well, but the shape of these openings is not necessarily important to function of the spring portion 13. An angle at which the radial portion 16 is arranged relative to a chord portion 14 between the intermediate point and an end 19 may be between about 45 degrees and 120 degrees, e.g., between 60 and 110 degrees. An angle between a line extending from the center 27 to an end 19 of a chord portion and a line extending from the center 27 to the intermediate point 20 of the chord portion 14 may be between about 25 and 90 degrees, e.g., between 30 and 60 degrees. Also, a distance between the intermediate point 20 of a chord portion 14 and the center 27 may be larger than a shortest distance between the center 27 and a line extending from the ends 19 of the chord portion 14. As will be understood, the spring portion 13 can be formed from a sheet of metal or other suitable material, e.g., by stamping or die cutting. Also, a spring portion 13 may have as few as two spring elements 17, although more than three, four or five spring elements 17 may be used. The spring elements 17 may be positioned symmetrically around the center 27, or may be arranged in a more irregular configuration.

Applications for the embodiments above can be found wherever energy is transferred to fluids by means of mechanical volumetric displacement. Applications include, for example, fluid movers such as pumps, compressors and synthetic jets; applying fluidic energy to fluid filled acoustic resonators for applications such as acoustic compressors or thermoacoustic engines, buzzers and as speaker elements in sound reproduction. Further applications include any product or device that needs a low profile spring that can provide relatively large displacements, low stresses and where the stiffness of the spring can be easily changed without adversely affecting stress.

The embodiments provided herein are not intended to be exhaustive or to limit the invention to a precise form disclosed, and many modifications and variations are possible in light of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Although the above description contains many specifications, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of alternative embodiments thereof.

The indefinite articles "a" and "an," as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean "at least one."

The phrase "and/or," as used herein in the specification and in the claims, should be understood to mean "either or both" of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases.

Multiple elements listed with "and/or" should be construed in the same fashion, i.e., "one or more" of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the "and/or" clause, whether related or unrelated to those elements specifically identified.

The use of "including," "comprising," "having," "containing," "involving," and/or variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

It should also be understood that, unless clearly indicated to the contrary, in any methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited.

While aspects of the invention have been described with reference to various illustrative embodiments, such aspects are not limited to the embodiments described. Thus, it is evident that many alternatives, modifications, and variations of the embodiments described will be apparent to those skilled in the art. Accordingly, embodiments as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit of aspects of the invention.

Claims

1. A fluid mover comprising:

a housing defining a chamber having one or more outlet openings;

a first fluidic diaphragm having a fluid-moving portion movable in the chamber to cause fluid to move at the outlet opening, and a spring portion having a center coupled to the fluid moving portion to bias the fluid-moving portion to a starting position, the spring portion including two or more spring elements, each spring element including a chord portion having an intermediate point and attached to the housing at opposite ends and a radial portion extending radially inwardly from the intermediate point to the center; and

a coil assembly in the chamber that is positioned adjacent the first fluidic diaphragm and magnetically coupled to the fluid-moving portion to move the fluid- moving portion in the chamber in response to a current in the coil.

2. The fluid mover of claim 1, wherein the chord portion has an arcuate shape with a concave side and a convex side, the concave side being positioned closer to the center than the convex side.

3. The fluid mover of claim 1, wherein the chord portion has a straight shape.

4. The fluid mover of claim 1 , wherein the intermediate point is at a midpoint between the opposite ends.

5. The fluid mover of claim 1, wherein the radial portion includes a rectangular portion that extends along a radial line extending from the center.

6. The fluid mover of claim 1 , wherein the radial portion tapers in width such that the radial portion is wider at an inner section nearer the center than an outer section.

7. The fluid mover of claim 1 , wherein the spring portion is planar.

8. The fluid mover of claim 1, wherein the spring portion is formed from a flat sheet of metal.

9. The fluid mover of claim 1 , wherein the spring portion and the fluid-moving portion are planar and are parallel to each other.

10. The fluid mover of claim 9, wherein the spring portion and the fluid-moving portion are attached together only at the center of the spring portion and a center of the fluid-moving portion.

11. The fluid mover of claim 1, wherein the coil assembly includes a coil with an opening, and at least one of a plug in the opening or a support around a periphery of the coil arranged to support the coil in the chamber, wherein the plug and/or the support includes a material with a relative magnetic permeability greater than one and is arranged such that magnetic field lines created by a current in the coil to cause movement of the fluid-moving portion pass through the plug and/or support.

12. The fluid mover of claim 11, comprising the plug and the support, wherein the plug and the support each include a material with a relative magnetic permeability greater than one.

13. The fluid mover of claim 11, wherein the first fluidic diaphragm and the coil assembly are arranged such that no portion of the fluidic diaphragm enters the opening of the coil during movement of the fluidic diaphragm.

14. The fluid mover of claim 11, comprising the plug, wherein the plug completely occludes the opening.

15. The fluid mover of claim 11, comprising the support, wherein support includes a plate that defines a hole at which the coil is supported by the support.

16. The fluid mover of claim 15, wherein the support is immediately adjacent the periphery of the coil around the hole.

17. The fluid mover of claim 16, comprising the plug, wherein the plug and the support each include a material with a relative magnetic permeability greater than one.

18. The fluid mover of claim 17, wherein the support, coil and plug define a flat structure.

19. The fluid mover of claim 17, wherein the fluid-moving portion includes an armature formed as a flat plate of material with a relative magnetic permeability greater than one.

20. The fluid mover of claim 15, wherein the first fluidic diaphragm is positioned over a top of the coil, the fluid mover further comprising a second fluidic diaphragm positioned under a bottom of the coil.

21. The fluid mover of claim 20, comprising the plug, wherein the support, coil and plug define a first flat surface opposed to the first fluidic diaphragm, and wherein the support, coil and plug define a second flat surface opposed to the second fluidic diaphragm.

22. The fluid mover of claim 20, comprising the plug, wherein the plug and the support each include a material with a relative magnetic permeability greater than one, and wherein the coil is arranged to move fluid-moving portions of the first and second fluidic diaphragms toward each other based on a current in windings of the coil.

23. The fluid mover of claim 22, wherein upper and lower gaps are present between the fluid-moving portion of the first fluidic diaphragm and the coil assembly, and between the fluid-moving portion of the second fluidic diaphragm and the coil assembly, respectively, and wherein the fluid mover is arranged to move fluid in the upper and lower gaps based on movement of the fluid-moving portion of the first and second fluidic diaphragms relative to the housing.

24. The fluid mover of claim 23, wherein the coil assembly is arranged to remain stationary relative to the chamber.

25. The fluid mover of claim 1, wherein the fluid-moving portion of the first fluidic diaphragm is arranged for vibratory movement in the chamber in which a portion of the fluid-moving portion moves at a frequency of 0.1 Hz to 1kHz or more.

26. The fluid mover of claim 1, wherein the fluid-moving portion has a periphery which is fixed relative to the chamber, and the coil assembly is arranged to move portions of the fluid-moving portion located inward of the periphery relative to the chamber.

27. The fluid mover of claim 1, wherein the coil has an annular shape.

28. The fluid mover of claim 1, wherein the fluid-moving portion includes a flat diaphragm surface opposed to the coil assembly.