Passive pressure regulation mechanism

A pump system including a drive mechanism that provides a pumping force, a primary pump including a first pump cavity, an actuating element in reciprocal relation with the first pump cavity, and an outlet fluidly connected to a reservoir, a force translator that facilitates pump force transfer from the drive mechanism to the actuating element, a pressure regulation mechanism including a reciprocating pump that includes a pump chamber including an inlet manifold fluidly connected to the reservoir, a valve located within the inlet manifold, and a reciprocating element in reciprocal relation with the pump chamber. The pressure regulation mechanism preferably passively ceases force transfer from the drive mechanism to the primary pump based on the pressure of the reservoir.

TECHNICAL FIELD

This invention relates generally to the pumping field, and more specifically to a new and useful passive pressure regulator in the pumping field.

BACKGROUND

Passive pressurization systems can be desirable in many applications, particularly in those wherein the extra weight of an electrical energy storage device or the additional complexity of digital controls can be detrimental or inconvenient. However, passive pressurization systems can suffer from over-pressurization of a reservoir, wherein the pressurization system continues to pump fluid into the reservoir even after the desired reservoir pressure is reached. Conventional systems typically resolve this problem with a relief valve, wherein the relief valve vents the reservoir contents into the ambient environment when the reservoir pressure exceeds or meets the desired pressure. These systems lack a feedback loop that ceases continued pressurization of the reservoir when the desired pressure is reached, thereby reducing pump cycles and increasing pump lifespan.

Thus, there is a need in the passive pressurization field to create a new and useful passive pressure regulation system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown inFIG. 1, the passive pressure regulation mechanism200of the pump system100includes a pump body220, an actuating mechanism240, and a valve260having a threshold opening pressure. The valve26can additionally include a threshold closing pressure. The pressure regulation mechanism200is preferably utilized in a pump system100that includes a reservoir20and a primary pump120driven by a drive mechanism300, wherein the primary pump120pressurizes the reservoir20. The passive pressure regulation mechanism200is preferably fluidly connected to a reservoir20by a fluid manifold and mechanically connected to a primary pump120, wherein the primary pump120receives a pumping force from the drive mechanism300to pump fluid into the reservoir20. The pressure regulation mechanism200preferably functions to passively cease pressurization of the reservoir20when a threshold reservoir pressure is reached. The pressure regulation mechanism200preferably ceases pressurization by ceasing force application from the drive mechanism300to the primary pump. Force application can be ceased by disconnecting the primary pump from the drive mechanism300, or by ceasing force generation at the drive mechanism300. This pressure regulation mechanism200can confer several benefits. First, the pressure regulation mechanism200passively controls the pressure of the reservoir20, eliminating the need for sensors and other powered components. Second, the pressure regulation mechanism200can additionally include a timing feature that controls the duration between pump system shut off and pump system restart.

The reservoir20fluidly coupled to the pressure regulation mechanism200preferably receives fluid pumped by the pump system100. The reservoir20preferably has a substantially large volume relative to the pressure regulation mechanism200, such that the pressure regulation mechanism200volume (i.e., the total volume defined by the actuating mechanism240and the valve260) is substantially insignificant relative to the reservoir volume (i.e., fluid flow into passive pressure regulation mechanism200does not significantly change the reservoir pressure). The reservoir volume can additionally be substantially large relative to the volume of the primary pump120, such that the primary pump volume is substantially insignificant relative to the reservoir volume. The reservoir20is preferably a tire interior, but can alternatively be a chamber, balloon, or any other suitable fluid reservoir20. The reservoir20is preferably fluidly connected to the pressure regulation mechanism200at an outlet, and fluidly connected to the primary pump120at an inlet.

The primary pump120of the pump system100functions to pump fluid into the reservoir20, thereby pressurizing the reservoir20. The primary pump120preferably includes a pump cavity122and an actuating element124that actuates within the pump cavity122. The primary pump120is preferably a positive displacement pump including a pump cavity122and actuating element124defining a lumen therebetween, wherein the actuating element124preferably forms a substantially fluid impermeable seal with and translates within the pump cavity122to create pressure differentials that move a fluid from the pump inlet to the pump outlet. However, the primary pump120can be any other suitable pump. The positive displacement pump is preferably a reciprocating pump wherein the pump cavity122is a pump chamber and the actuating element124is a reciprocating element, but can alternatively be a peristaltic pump, wherein the pump cavity122is a groove221(e.g., circumferential groove) and the actuating element124is a diaphragm or tube. The reciprocating element can be a diaphragm, a piston, a diaphragm actuated by a piston (e.g., wherein the diaphragm defines the lumen and the piston receives the pumping force from the diaphragm to actuate the diaphragm, etc.), or any other suitable reciprocating element. The primary pump120is preferably operable between a pumping mode and a non-pumping mode. In the pumping mode, the actuating element124receives a pumping force from a drive mechanism300and translates along an actuation axis between a compressed position, wherein the actuating element124is proximal the closed end of the pump cavity122, and a recovered position, wherein the actuating element124is distal the closed end. In the non-pumping mode, the actuating element124preferably does not receive a pumping force from the drive mechanism300, and fluid movement through the primary pump120is preferably ceased.

The pump system100preferably additionally includes a force translator400that functions to connect the primary pump120to the drive mechanism300. More preferably, the force translator400functions to connect the actuating element124to the drive component321(e.g., cam320), wherein the force translator400translates relative motion between the drive mechanism300and the primary pump120into a variable occluding force. The force translator400preferably applies a force in a radially outward direction from the rotational axis, but can alternatively apply a force in a radially inward direction, in a direction substantially parallel to the rotational axis, in a direction at an angle to the rotational axis, or in any other suitable direction. In a first alternative of the pump system100, the force translator400includes a planetary roller401that rolls about an interior or exterior arcuate surface of the cam (e.g., as disclosed in U.S. application Ser. No. 13/187,848, filed 21 Jul. 2011, incorporated herein in its entirety by this reference, but any other suitable system can be used). This alternative is preferably used when the primary pump120is a peristaltic pump, but can alternatively be used for any other suitable pump system100. In a second alternative of the pump system100, the force translator400is a roller with a rotational axis that is statically fixed to a point on the pump cavity122, more preferably to the actuation axis of the primary pump120. This alternative is preferably used with a reciprocating pump, but can alternatively be used with any other suitable pump. The roller is preferably in non-slip contact with a bearing surface of the cam320, wherein the cam32opreferably has a bearing surface with a varying curvature, such that the roller applies a variable force to the actuating element124as the roller rolls over the variable bearing surface. The roller slides relative to the actuating element124, but can alternatively contact the actuating element124in any other suitable manner. In a third alternative of the pump system100, the force translator400includes a linkage rotatably connected to a fixed point on the cam320and rotatably coupled to the actuating element124, wherein the linkage preferably actuates the actuating element124through a compression stroke and a recovery stroke as the fixed point nears and retreats from the pump cavity position, respectively. Alternatively, the linkage can actuate the actuating element124through the compression stroke and recovery stroke as the fixed point retreats from and nears the pump cavity122, respectively. The linkage preferably includes a single link, but can alternatively include two or more links rotatably connected at the respective ends. In a fourth alternative of the pump system100, the force translator400includes a keyed piece that joins with a complimentary piece on drive mechanism300(e.g., tooth and gear). However, any other suitable force translator400can be used.

The drive mechanism300of the pump system100functions to provide a pumping force to the primary pump120. The pumping force is preferably variable, but can alternatively be constant. The drive mechanism300is preferably passive and couples to a moving surface, but can alternatively be active (e.g., driven by a motor, etc.). The moving surface is preferably a rotating surface (a surface configured to rotate, such as a tire), but can alternatively be an oscillating surface (e.g., a wave), or any other suitable surface. The drive mechanism300preferably generates the pumping force by facilitating relative motion between the drive mechanism300and the primary pump120. In one variation of the pump system100, the primary pump120is statically coupled to a rotating surface while the drive mechanism300is held substantially static relative to the frame in which the rotating surface is rotating. For example, the rotating surface can rotate relative to a gravity vector, wherein the drive mechanism300is held substantially static relative to the gravity vector. However, the pumping force can be otherwise generated. The drive mechanism300preferably includes a force generator and a drive interface, wherein the force generator generates the pumping force, and the drive interface couples to the force translator400. However, the drive mechanism300can be otherwise configured. The pump system100preferably includes one drive mechanism300for each primary pump120, but can alternatively include one drive mechanism300for multiple primary pumps, or have any other suitable configuration.

In one variation of the pump system100, the drive mechanism300includes a cam320and an eccentric mass340. This drive mechanism300is preferably configured to statically couple to a rotating surface, but can alternatively be coupled to other surfaces. This drive mechanism300preferably generates a pumping force (occluding force) in a radial direction from a rotational axis of the drive mechanism300, but can alternatively be a constant force, a force applied at any suitable angle to the rotational axis, or any other suitable force. The drive mechanism300includes a rotational axis about which the drive mechanism300rotates relative to the primary pump120(conversely, about which the primary pump120rotates relative to the drive mechanism300). The rotational axis of the drive mechanism300is preferably the rotational axis of the cam320, but can alternatively be the rotational axis of the eccentric mass340, the rotational axis about which the primary pump rotates, or any other suitable rotational axis. The pump system100is preferably configured such that the rotational axis of the drive mechanism300is substantially aligned with the rotational axis of the rotating surface when the pump system100is coupled to the rotating surface, but the pump system100can alternatively be configured such that the rotational axis of the drive mechanism300is offset from the rotational axis of the rotating surface. The drive mechanism300additionally includes a center of mass, determined from the mass and positions of the cam320and the eccentric mass340. The eccentric mass340is preferably coupled to the cam320such that the center of mass of the drive mechanism300is offset from the rotational axis of the drive mechanism300.

The cam320of the drive mechanism300functions to provide a surface against which the pumping force is generated. In a first variation, the cam320includes an arcuate bearing surface that interfaces with the primary pump120. More preferably, the arcuate bearing surface interfaces with a roller force translator400of the primary pump120. In one alternative, the cam320includes a bearing surface with a variable curvature that controls the magnitude of the substantially linear, radial force applied to the primary pump120. The cam320preferably functions to provide a substantially constant torque against the reciprocating element throughout the compression stroke, but can alternatively provide a variable torque against the reciprocating element throughout the compression or recovery strokes. The cam320preferably includes a bearing surface, wherein the profile of the bearing surface preferably controls the magnitude of the force throughout the compression stroke. The bearing surface is preferably continuous, but can alternatively be discontinuous. The bearing surface is preferably defined on the exterior of the cam320(exterior bearing surface or outer bearing surface) but can alternatively be defined within the interior of the cam320(interior bearing surface or inner bearing surface), wherein the bearing surface defines a lumen within the cam320. The bearing surface is preferably arcuate, and preferably has a non-uniform curvature (e.g., a reniform profile). Alternatively, the bearing surface can have a uniform curvature (e.g., a circular profile), an angular profile, or any other suitable profile. The bearing surface preferably includes a compression portion and a recovery portion, corresponding to the compression stroke and the recovery stroke of the primary pump120, respectively. The compression portion is preferably continuous with the recovery section, but can alternatively be discontinuous. The bearing surface preferably has a first section having a high curvature (preferably positive curvature or convex but alternatively negative curvature or concave) adjacent a second section having low curvature (e.g., substantially flat or having negative curvature compared to the first section). The bearing surface preferably additionally includes a third section connecting the first and second sections, wherein the third section preferably provides a substantially smooth transition between the first and second sections by having a low curvature adjacent the first section and a high curvature adjacent the second section. The compression portion preferably begins at the end of the second section distal the first section, extends along the third section, and ends at the apex of the first section. The compression portion is preferably convex (e.g., when the bearing surface is an external bearing surface), but can alternatively be concave. The apex of the first section preferably corresponds to the top of the compression stroke (compressed position). The recovery portion preferably begins at the apex of the first section, extends along the second section, and ends at the end of the second section distal the first section. The recovery portion is preferably substantially flat or concave (e.g., when the bearing surface is an external bearing surface), but can alternatively be convex. The end of the second section preferably corresponds to the bottom of the recovery stroke (recovered position). The slope of the compression portion is preferably less than 30 degrees, but can alternatively have any suitable angle. When a roller is used as the force translator400, the curvature of the bearing surface is preferably at least three times larger than the roller curvature or roller diameter, but can alternatively be larger or smaller. However, the bearing surface can have any suitable profile. The cam320is preferably substantially planar with the bearing surface defined along the side of the cam320, in a plane normal to the rotational axis of the cam (e.g., normal the broad face of the cam). The bearing surface is preferably defined along the entirety of the cam side, but can alternatively be defined along a portion of the cam side. The generated pump force is preferably directed radially outward of the rotational axis, more preferably along a plane normal to the rotational axis. Alternatively, the cam320can have a rounded or otherwise profiled edge segment (transition between the cam broad face and the cam side), wherein the bearing surface can include the profiled edge. Alternatively, the arcuate surface is defined by a face of the cam parallel to the rotational axis of the cam320, wherein the generated pump force can be directed at any suitable angle relative to the rotational axis, varying from parallel to the rotational axis to normal to the rotational axis. The compression portion preferably encompasses the majority of the cam profile, but can alternatively encompass half the cam profile or a small portion of the cam profile. In one variation, the compression portion covers 315 degrees of the cam profile, while the recovery portion covers 45 degrees of the cam profile. However, the compression and recovery portions can cover any other suitable proportion of the cam profile.

In another alternative, the cam320is a disk with a substantially circular profile. In yet another alternative, the cam320is a sphere segment or catenoid, wherein the bearing surface is preferably defined along the arcuate surface. In yet another alternative, the cam320is a bearing rotatably coupled about an axle statically coupled to the rotating surface. The cam320can alternatively have any other suitable form factor or configuration.

The eccentric mass340(hanging mass) of the drive mechanism300functions to offset the center of mass of the drive mechanism300from the rotational axis of the drive mechanism300. This offset can function to substantially retain the angular position of the cam320relative to a gravity vector, thereby engendering relative motion between the drive mechanism300and the primary pump120statically coupled to the rotating surface (that rotates relative to the gravity vector). The eccentric mass340is preferably a substantially homogenous piece, but can alternatively be heterogeneous. The eccentric mass340is preferably a distributed mass (e.g., extends along a substantial portion of an arc centered about the rotational axis), but can alternatively be a point mass. The eccentric mass340is preferably curved, but can alternatively be substantially flat, angled, or have other suitable shapes. The radius of the eccentric mass curvature is preferably maximized, such that the eccentric mass340traces an arcuate section of the energy extraction system perimeter. However, the eccentric mass340can have any other suitable curvature. The eccentric mass340preferably extends at least 80 degrees about the rotational axis of the drive mechanism300, more preferably 180 degrees about the rotational axis, but can extend more or less than 180 degrees about the rotational axis. The eccentric mass340preferably has substantially more mass than the cam320, but can alternatively have a substantially similar mass or a smaller mass. The eccentric mass340preferably imparts 2 in-lb (0.225 Nm) of torque on the cam320, but can alternatively impart more or less torque.

The eccentric mass340is preferably a separate piece from the cam320, and is preferably coupled to the cam320by a mass couple360. The eccentric mass340can be statically coupled to the cam320or rotatably coupled to the cam320. In the variation wherein the eccentric mass340is statically coupled to the cam320, the eccentric mass340can be coupled to the cam320at the rotational axis of the cam320, at the rotational axis of the drive mechanism300, offset from the rotational axis of the cam320, or at any other suitable portion of the cam320. The eccentric mass340can be permanently connected to the cam320. Alternatively, the eccentric mass340can be transiently connected (removably coupled) to the cam320, wherein the eccentric mass340can be operable between a coupled mode wherein the eccentric mass340is coupled to the cam320and a decoupled mode wherein the eccentric mass340is rotatably coupled to the cam320or otherwise decoupled from angular cam motion. The mass couple360preferably has a high moment of inertia, but can alternatively have a low moment of inertia. The mass couple360is preferably a disk, but can alternatively be a lever arm, plate, or any other suitable connection. The mass couple360preferably couples to the broad face of the cam320, but can alternatively couple to the edge of the cam320, along the exterior bearing surface of the cam320, to the interior bearing surface of the cam320, to an axle extending from of the cam320(wherein the cam320can be statically fixed to or rotatably mounted to the axle), or to any other suitable portion of the cam320. The mass couple360can couple to the cam320by friction, by a transient coupling mechanism (e.g., complimentary electric or permanent magnets located on the cam320and mass couple360, a piston, a pin and groove mechanism, etc.), by bearings, or by any other suitable coupling means.

In another variation of the pump system100, the drive mechanism300can be a linear actuator, such as a mechanical actuator, hydraulic actuator, pneumatic actuator, piezoelectric actuator, electro-mechanical actuator, or any other suitable linear actuator. The actuating portion of the linear actuator preferably connects to the actuating element124of the primary pump120, but can alternatively connect with the pump cavity122of the primary pump120. The linear actuator is preferably passive, but can alternatively be driven by a motor (e.g., an electric motor).

In another variation of the pump system100, the drive mechanism300can be rotary actuator, such as a torque motor, electric motor, servo, stepper motor or any other suitable rotary actuator. The actuating portion of the rotary actuator preferably connects to the actuating element124of the primary pump120through the force translator400that converts the rotational motion into a linear motion, but can alternatively connect with the pump cavity122of the primary pump120through the force translator400.

The pressure regulation mechanism200of the pump system100functions to cease pumping of the primary pump120when the reservoir pressure exceeds a threshold pressure. The pressure regulation mechanism200includes a pump body220, an actuating mechanism240, and a valve260, wherein the valve260is fluidly connected to the pump body inlet and the actuating mechanism240actuates relative to a closed end of the pump body220. The pump body220and actuating mechanism240preferably form a piston pump, wherein the pump body220is a pump chamber and the actuating mechanism240is a reciprocating element. The pump body220and actuating mechanism240can alternatively form any other suitable reciprocating pump or positive displacement pump. As shown inFIGS. 2A and 2B, the pressure regulation mechanism200is preferably operable in a pressurized mode and a depressurized mode. The pressurized mode is preferably achieved when the reservoir pressure exceeds the threshold pressure. More preferably, the pressurized mode is achieved when the reservoir pressure exceeds the opening pressure of the valve260. In the pressurized mode, the valve260is preferably in an open position and permits fluid flow from the reservoir20into the pump body220, wherein the pressure of the ingressed fluid places the actuating mechanism240in a pressurized position. In the pressurized position, the actuating mechanism240preferably ceases pumping force application to the primary pump120. In the depressurized mode, the valve260is preferably in a closed position and prevents fluid flow from the reservoir20into the pump body220, wherein a return mechanism places the actuating mechanism240in a depressurized position. The pump system100preferably includes at least one pressure regulation mechanism200, but can alternatively include any suitable number of pressure regulation mechanisms.

The position of the pressure regulation mechanism200, more preferably the position of the pump body220, is preferably statically connected to the primary pump position, but can alternatively be moveably connected to the primary pump position. The angular position of the pressure regulation mechanism200is preferably maintained relative to the primary pump position, but the radial or linear distance can alternatively be maintained. The actuation axis of the pressure regulation mechanism200is preferably in the same plane as the actuation axis of the primary pump120, but can alternatively be in different planes, perpendicular to the actuation axis of the primary pump120, or arranged in any other suitable manner. The pressure regulation mechanism200is preferably arranged relative to the primary pump120such that the direction of the compression stroke of the pressure regulation mechanism200differs from the direction of the compression stroke of the primary pump120. The direction of the compression stroke of the pressure regulation mechanism200directly opposes the direction of the compression stroke of the primary pump120(e.g., the closed end of the pump cavity122is distal the closed end of the pump body220, and the actuating element124is proximal the reciprocating element, wherein the actuation axes are aligned or in parallel), but can alternatively be at an angle to the direction of the compression stroke of the primary pump120. Alternatively, the pressure regulation mechanism200can be arranged such that the compression stroke of the pressure regulation mechanism200and the compression stroke of the primary pump120have substantially the same direction (e.g., the actuation axes are aligned or in parallel).

The pump body220functions to cooperatively define a pressurizable lumen with the actuating mechanism240. The pump body220is preferably substantially rigid, but can alternatively be flexible. The pump body220is preferably an open pump body220with a closed end, wherein the pump body220preferably includes a closed end (bottom), walls extending from the closed end, and an opening opposing the closed end. However, the pump body220can alternatively have two open ends or any other suitable configuration. The closed end is preferably substantially flat, but can alternatively be curved or have any other suitable geometry. The walls are preferably substantially flat, but can alternatively be curved or have any other suitable geometry. The walls preferably join with the closed end at an angle, more preferably at a right angle, but the transition between the walls and the closed end can alternatively be substantially smooth (e.g., have a bell-shaped or paraboloid longitudinal cross section). The closed end is preferably substantially parallel to the opening defined by the walls, but can alternatively be oriented at an angle relative to the opening. The pump body220can be a groove defined in an arcuate or prismatic piece (e.g., in a longitudinal or lateral direction), a cylinder, a prism, or any other suitable shape. The pump body220preferably has a substantially symmetrical lateral cross section (e.g., circular, ovular, or rectangular cross section, etc.), but can alternatively have an asymmetrical cross section. The pump body220is preferably oriented within the pump system100such that the closed end is substantially normal to a radial vector extending from the rotational axis of the drive mechanism300(e.g., the normal vector from the closed end is substantially parallel to the radial vector), but can alternatively be oriented with the closed end at an angle to the radial vector. The pump body220is preferably oriented with the opening proximal and the closed end distal the rotational axis, particularly when the pump body220rotates about the cam exterior, but can alternatively be oriented with the opening distal and the closed end proximal the rotational axis, particularly when the pump body220rotates about the cam interior, or oriented in any other suitable position relative to the rotational axis.

The actuating mechanism240functions to control the pumping mode of the primary pump120based on the pressure within the pump body220. The actuating mechanism240preferably translates within the pump body220. The actuating mechanism240preferably forms a fluid seal with the pump body220to define a lumen, but can alternatively be located within the lumen of the pump body220. The actuating mechanism240preferably translates along an actuation axis substantially aligned with the longitudinal axis of the pump body220, but can alternatively actuate along any other suitable axis. The actuating mechanism240is preferably a piston coupled to a diaphragm, but can alternatively be a substantially flat surface, a piston, a roller, a cup, be substantially similar to the force translator400, or have any other suitable form factor. The diaphragm is preferably a domed diaphragm with a folded perimeter, but can alternatively be any other suitable diaphragm.

The actuating mechanism240is preferably operable between a pressurized position and a depressurized position, corresponding to the pressurized mode and depressurized mode, respectively. The pressurized position is preferably achieved when the pump body lumen is pressurized to the threshold or reservoir pressure, and the depressurized position is preferably achieved when the pump body lumen is at a pressure less than the threshold pressure. The actuating mechanism240is preferably located at a position distal the closed end of the pump body220in the pressurized position, and is preferably located at a position proximal the closed end of the pump body220in the depressurized position. The actuating mechanism240can be beyond the pump body220, level with the pump body opening, or encompassed by the pump body220when in the pressurized position. The actuating mechanism240is preferably level with the pump body opening or encompassed by the pump body220(retracted within the lumen) when in the depressurized position, but can alternatively be beyond (external) the pump body220when in the depressurized position. The actuating mechanism240can additionally include a return element (e.g., a spring, the primary pump120, another pressurizable compartment, etc.) that applies a return force to return the actuating mechanism240to the depressurized position.

The depressurized position can include a compressed position and a recovered position. In the compressed position, a portion of the actuating mechanism240(e.g., the center) is preferably proximal the pump body closed end. In the recovered position, the portion of the actuating mechanism240is preferably distal the pump body closed end, and is preferably proximal the pump body opening. The actuating mechanism240preferably travels along a compression stroke to transition from the recovered position to the compressed position, and travels along a recovery stroke to transition from the compressed position to the recovered position.

In a first variation of the pressure regulation mechanism200, the actuation mechanism decouples the primary pump120or a primary pump component from drive mechanism300when in the pressurized position, and permits primary pump coupling with the drive mechanism300when in the depressurized position. An example of this variation in the depressurized and pressurized positions is shown inFIGS. 3A and 3B, respectively. The actuating mechanism240preferably decouples the force translator400from the drive mechanism300, but alternatively decouples the actuating element124or the entirety of the primary pump120from the drive mechanism300. The actuating mechanism240preferably moves the primary pump component along the actuation axis of the primary pump120, away from the cam320, when transitioning from the depressurized position to the pressurized position. However, the actuating mechanism240can move the primary pump component at an angle to the actuation axis of the primary pump120, away from the cam320(e.g., in a perpendicular direction). The actuating mechanism240preferably translates the primary pump component within the plane encompassing the actuation axis or the pump body220, but can alternatively translate the primary pump component out of said plane. The force exerted on the actuating mechanism240by the return element of the pump regulation system preferably couples the primary pump component with the drive mechanism300while returning the actuating mechanism240to the depressurized position, but the pump system100can alternatively include a second return element that couples the primary pump component to the drive mechanism300(e.g., a spring biased opposing the direction that the actuating mechanism240moves the primary pump component, etc.). The second return element preferably returns the primary pump component contact with the drive mechanism300when the decoupling force of the actuating mechanism240falls below the return force provided by the second return element.

A portion of the actuating mechanism240is preferably statically coupled to a portion of the primary pump120, wherein actuating mechanism actuation results in a positional change of the primary pump120or a primary pump component. More preferably, actuating mechanism actuation preferably selectively couples and decouples the primary pump120from the drive mechanism300when the actuating mechanism240is in the depressurized and pressurized positions, respectively. The actuating mechanism240is statically coupled to the force translator400, but can alternatively be statically coupled to the actuating element124, statically coupled to the primary pump120as a whole, or statically coupled to any other suitable primary pump component. The actuating mechanism240is preferably statically coupled to the primary pump component by a frame242, but can alternatively be coupled by a housing encapsulating the pump system100, or by any other suitable coupling mechanism. The frame242can be aligned within the plane encompassing the actuation axis of the primary pump120, within the plane encompassing the actuation axis of the pressure regulation mechanism200, extend out of either of said two planes, or be otherwise oriented relative to the pump system100. In a specific example, the force translator400is a roller, wherein the actuating mechanism240is coupled to the rotational axis of the roller by a frame242aligned with a plane encompassing both the actuation axis of the pressure regulation mechanism200and the actuation axis of the primary pump120(wherein the pressure regulation mechanism200and primary pump120preferably share a common plane). Alternatively, the actuating mechanism240transiently couples to the primary pump component when in the pressurized position, and is retracted away from the primary pump component when in the depressurized position.

In a second variation of the pressure regulation mechanism200, the actuating mechanism240decouples the force translator400from the primary pump120in the pressurized position, and permits force translator coupling with the primary pump120when in the depressurized position. An example of this variation in the depressurized and pressurized positions is shown inFIGS. 4A and 4B, respectively. The actuating mechanism240preferably connects to and moves the force translator linear position relative to the drive mechanism300when in the pressurized position, but can alternatively connect to and move the primary pump120relative to the force translator400and drive mechanism300. The actuating mechanism240preferably moves the force translator400out of the common plane shared by the primary pump120and the drive mechanism300, but can alternatively move the force translator400out of line with the actuation axis (e.g., perpendicular, within the common plane). The actuating mechanism240can be statically coupled to the force translator400or primary pump120by a frame242, a weld, or any other suitable coupling mechanism. Alternatively, the actuating mechanism240can be transiently coupled to the force translator400or primary pump120, wherein the actuating mechanism240can be a piston or rod that transiently couples to the force translator400or primary pump120through a coupling feature (e.g., a groove) or friction.

In a third variation of the pressure regulation mechanism200, the actuating mechanism240ceases force generation. In one alternative, the pressure regulation mechanism200statically couples the drive mechanism300to the primary pump120, ceasing force generation by eliminating the relative motion between the drive mechanism300and the primary pump120. Examples of this variation in the depressurized position are shown inFIGS. 5A and 6A, respectively, and pressurized positions are shown inFIGS. 5B and 6B, respectively. For example, when the drive mechanism300includes a cam320and eccentric mass340, the actuating mechanism240can statically couple the angular position of the cam320with the angular position of the primary pump120in the pressurized position, and decouple the angular position of the cam320from the angular position of the primary pump120in the depressurized position. In a specific example, the actuating mechanism240is a rod that couples to the cam broad face by friction. In another specific example, the actuating mechanism240is a rod that extends into a groove in the cam face when in the pressurized position and is retracted from the groove when in the depressurized position. In another specific example, the actuating mechanism240statically couples to the arcuate bearing surface of the cam320. However, other mechanisms of transiently retaining the cam angular position can be envisioned. In another example, the actuating mechanism240can statically couple the angular position of the eccentric mass340with the angular position of the primary pump120. In a specific example, the actuating mechanism240can include a rod that couples to the broad face of the eccentric mass340or to the mass couple360by friction. In another specific example, the actuating mechanism240is a rod that extends into a groove in the eccentric mass face when in the pressurized position and is retracted from the groove when in the depressurized position. However, other mechanisms of transiently retaining the eccentric mass angular position can be envisioned. In another example, the pump cavity122of the primary pump120can be statically coupled to the drive mechanism300, such that relative motion between the actuating element124and the pump cavity122is ceased (e.g., when a linear or rotary actuator is used). In another alternative, the pressure regulation mechanism200decouples the force generator from the drive interface of the drive mechanism300. For example, when the cam320and eccentric mass340are transiently coupled by a transient coupling mechanism, the actuating mechanism240can actuate the cam320, eccentric mass340, or coupling mechanism to decouple the cam320from the eccentric mass340. In one specific example, if the cam320is coupled to the eccentric mass340along the respective broad faces by a ring of magnets362encircling the rotational axis, as shown inFIG. 7A, the actuating mechanism240can extend through a hole in the cam320(or eccentric mass340) and push against the broad face of the eccentric mass340(or cam320) to decouple the eccentric mass340from the cam320, as shown inFIG. 7B. The actuating mechanism240can be statically coupled to the force translator400or primary pump120by a frame242or other coupling mechanism. Alternatively, the actuating mechanism240can be transiently coupled to the force translator400or primary pump120, wherein the actuating mechanism240can be a piston or rod that couples to the force translator400or primary pump120.

In another variation of the pressure regulation mechanism, the pressure regulation mechanism200switches the primary pump120from the pumping mode and a locked mode. The primary pump120preferably pumps fluid in the pumping mode and does not pump fluid in the locked mode. More preferably, components of the pump system are held in static relation relative to each other in the locked mode, such that the actuating element124is held substantially static. The primary pump120is preferably placed in the locked mode when the pressure of the reservoir20exceeds the opening threshold pressure of the valve260, and is preferably placed in the pumping mode when the pressure of the reservoir20falls below the closing threshold pressure of the valve260. More specifically, when the pressure of the reservoir20exceeds the opening threshold pressure, the valve260opens, allowing pressurized air to flow from the reservoir20into the compression volume of the primary pump120, substantially retaining the actuating element124in the initial position of the compression stroke (e.g., in the recovered position). In this manner, the increased force of pressurized air on the actuating element124substantially opposes cam motion when the actuating element124is located at the second section of the cam profile, but can alternatively or additionally oppose cam motion when the actuating element124is located at the first section or third section of the cam profile. Since the cam320is preferably configured to only apply a small force to the actuating element124at the second section, the cam320cannot overcome the large back force applied by the backflow on the actuating element124. These aspects of the pump system effectively cease pumping within the primary pump120. The force applied by the backflow prevents cam movement relative to the primary pump120, causing the cam320and subsequently, the eccentric mass340, to rotate with the pump system10. When the pump system includes multiple pumps, all the pumps are preferably flooded with pressurized air. Alternatively, a single pump can be flooded with pressurized air, alternating pumps can be flooded with pressurized air, or any other suitable subset of the pumps can be flooded to cease pumping.

However, any other suitable means of ceasing pumping force application to the actuating element can be used.

The valve260of the pressure regulation mechanism200functions to selectively permit fluid flow into the pump body220of the pressure regulation system. The valve260preferably has an opening threshold pressure substantially equal to the desired reservoir pressure (e.g., the upper limit of a desired reservoir pressure range), and can additionally have a closing threshold pressure under, over, or equal to the desired reservoir pressure (e.g., the lower limit of a desired reservoir pressure range). The valve260can additionally function as a timer, and have a pumping resumption pressure at which primary pump pumping is resumed. The pumping resumption pressure is preferably determined by the ratio of the first and second pressurization areas within the valve. Alternatively, the pressure regulation mechanism800can include a timer that functions to delay the resumption of pumping after the closing threshold pressure is reached. The valve260is preferably located in the fluid manifold fluidly connecting the reservoir20with the pump body220. However, the valve260can be located within the reservoir20or within the pump body inlet. The opening threshold pressure is preferably a higher pressure than the closing threshold pressure, wherein the opening and closing threshold pressures are preferably determined by the return force applied by the return element. The valve state is preferably determined by the pressure within the second reservoir500. The pumping resumption pressure is preferably lower than the closing threshold pressure, but can alternatively be higher than the closing threshold pressure or be any suitable pressure. The valve260is preferably operable between an open mode when a reservoir pressure exceeds an opening threshold pressure, wherein the valve260permits fluid flow from the reservoir20into the pump body220, and a closed mode when the reservoir pressure is below the closing threshold pressure, wherein the valve260prevents fluid flow from the reservoir20into the pump body220. Pumping by the primary pump200is preferably resumed when the pressure within the second pump820falls below the pumping resumption pressure, but can alternatively be resumed when the reservoir pressure falls below the closing threshold. The valve260is preferably a snap-action valve, but can alternatively be any other suitable valve. The valve260preferably includes a valve member261that seats within a valve body262, and can additionally include a return mechanism263(e.g., a spring) that biases the valve member261against the valve body262. The valve member261and valve body262can be different materials (e.g., to compensate for material expansion due to temperature changes), or can be made of the same material or materials with similar expansion coefficients.

In one variation of the pressure regulation mechanism200, the snap-action valve is substantially similar to the valve described in U.S. application Ser. No. 13/468,007 filed 10 May 2012.

In another variation of the pressure regulation mechanism200, as shown inFIG. 8, the snap-action valve includes a valve member261, a valve body262, a spring, a first volume264, a second volume265, a reservoir channel266, and a manifold channel267. The spring, or return element263, biases the valve body262against the valve member261. The spring constant of the spring is preferably selected based on the desired reservoir pressure (threshold pressure or cracking pressure) and the desired valve operating characteristics. The first volume264is preferably defined between the valve body262and valve member261, and preferably has a first pressurization area normal to a direction of spring force application. The second volume265is preferably also defined between the valve body262and valve member261, and preferably has a second pressurization area normal to the direction of spring force application. The reservoir channel266preferably fluidly connects the first volume264with the reservoir20. The manifold channel267is preferably defined through the valve body262, and is preferably fluidly connected to the pressure regulation mechanism200. The manifold channel267is preferably defined along the axis of return force application, opposing the return element across the valve member261, but can alternatively be defined in any other suitable location. The valve260can additionally include a timing mechanism276fluidly coupling the second volume265to an ambient environment, wherein the timing mechanism276preferably leaks air at a substantially controlled rate. In one variation, the timing mechanism276is a timing channel2ythat has a cross section selected based on a desired leak rate. The ratio of the first pressurization area to the second pressurization area is preferably selected based on the desired amount of time the valve260takes to recover the closed position, but can alternatively be any suitable ratio. However, the timing mechanism can be a porous plug (e.g., wherein the porosity can be selected based on the desired leak rate), an air permeable membrane, or any other suitable gas permeable mechanism that leaks air at a controlled rate. The combined volume of the first and second volumes are preferably substantially insignificant relative to the reservoir volume. The valve260is preferably operable between an open position and closed position. In the open position, the valve body262and valve member261cooperatively define a connection channel fluidly connecting the first volume264with the second volume265, wherein the valve member261is located distal the valve body262. The open position is preferably achieved when a pressure force generated by a pressure within the first volume264overcomes the spring force applied by the spring on the valve body262. In the closed mode, the valve member261and valve body262cooperatively seal the connection channel and the valve member261substantially seals the manifold channel267, wherein the valve member261seats against the valve body262. The closed mode is preferably achieved when the pressure force is lower than the applied spring force. In one alternative of the valve260, the valve member261has a symmetric cross section including a stem270configured to fit within the manifold channel267, a first overhang extending from the stem, and a second overhang extending from the first overhang. The valve body262includes a cross section complimentary to the valve member cross section, including a first step271defining the manifold channel267, a second step272extending from the first step, and walls extending from the second step. The first volume264is preferably defined between the second step272and the second overhang268the second volume265is preferably defined, between the first step271and the first overhang269, and the connection channel is preferably defined between a transition from the first overhang to the second overhang and a transition between the first step to the second step. The valve260can further include gaskets bordering and cooperatively defining the first and second volumes265. In one alternative of the valve260, the valve260includes a first gasket273located within the connection channel275that forms a first substantially fluid impermeable seal with the valve member261in the closed mode and a second fluid impermeable seal274defined between the second overhang and the walls. The valve260can additionally include a gasket within the manifold channel267that forms a fluid impermeable seal with the stem when the valve260is in the closed mode (e.g., to cooperatively define the second volume265), and permits fluid flow therethrough when the valve260is in the open mode.

In one embodiment of the pump system100, as shown inFIGS. 3A and 3B, the pump system moo includes a first and a second reciprocating pump, a drive mechanism300, a first and a second force translator (400and402, respectively) connected to the first and second reciprocating pumps, respectfully, the first and second force translators having a first and second axis in fixed relation, respectively, a fluid manifold210(e.g., inlet manifold211) fluidly connecting the second reciprocating pump to a reservoir20, and a valve260located within the fluid manifold210. The first pump preferably includes an outlet fluidly connected to the reservoir20, wherein the first pump pumps fluid to and pressurizes the reservoir20(as shown inFIG. 9A). The first pump preferably includes an inlet fluidly connected to a fluid source, wherein the fluid source can be the ambient environment, the housing (e.g., wherein the housing encloses desiccated air), or any other suitable fluid source. The second pump can additionally include an inlet (separate from that coupled to the fluid manifold but alternatively the same one) and an outlet fluidly connected to the fluid source and reservoir20, respectively wherein the second pump can pump fluid to and pressurize the reservoir20. Alternatively, the inlet and outlet of the second pump can be fluidly connected to the fluid source and to the inlet of the first pump, respectively, thereby forming a two-stage pump. In this alternative, fluid is pressurized to a first pressure within the second pump and pressurized to a second pressure at the first pump. The first and second reciprocating pumps preferably include a first and second pump chamber, respectively, and a first and second reciprocating element, respectively. The first and second reciprocating pumps preferably share a common plane (e.g., the respective actuating axes share a common plane), but can alternatively be located in different planes. The first and second reciprocating pumps are preferably equally radially distributed about the drive mechanism300, more preferably equally distributed about the rotational axis of the drive mechanism300. However, the pumps can be otherwise distributed. The positions of the first and second pump chambers are preferably statically fixed by a housing or other component, wherein the housing statically couples the pump system100to a rotating surface and can additionally enclose the pump system100. The first and second reciprocating pumps preferably oppose each other, wherein the closed end of the first pump chamber is distal the closed end of the second pump chamber and the first reciprocating element is proximal the second reciprocating element. The first reciprocating element preferably has a first pressurization area (area that receives or generates a pressure force) and the second reciprocating element preferably has a second pressurization area. The first pressurization area is preferably smaller than the second pressurization area, but can alternatively be larger or smaller. The drive mechanism300preferably includes a rotational axis, a cam320rotatable about the rotational axis, the cam320having a bearing surface, and an eccentric mass340coupled to the cam320that offsets the center of mass of the drive mechanism300from the rotational axis. The first force translator400is preferably couplable to the bearing surface of the cam320in non-slip contact, and is preferably statically connected to the reciprocating element of the first pump along an axis (e.g., rotational axis). The second force translator400preferably slips relative to the bearing surface of the cam320, but can alternatively couple in non-slip contact with the bearing surface. The second force translator400is preferably statically connected to the reciprocating element of the second pump along an axis (e.g., rotational axis). The first and second force translators can each be a roller, a piston, a piston coupled to the roller at the rotational axis, or any other suitable force translator400. The positions of the first and second force translators are preferably statically retained by a frame242, but can alternatively be retained by any other suitable mechanism. The frame242preferably surrounds the drive mechanism300, such that the drive mechanism300is located within the area bounded by the frame242. However, the frame242can be otherwise arranged relative to the drive mechanism300. The frame242is preferably located in the common plane shared by the first and second pumps, but can alternatively be located in a separate plane (e.g., extend normal to said plane and extend along a second plane parallel to the first). In operation, a radial or linear position of the frame242preferably shifts from a first position to a second position relative to a point on the drive mechanism300(e.g., rotational axis) when the second reciprocating element moves from the depressurized position to the pressurized position, respectively. The distance between the first position and the second position is preferably substantially similar to the distance between the depressurized position and the pressurized position, but can alternatively be larger (e.g., wherein the frame242amplifies the change in reciprocating element position) or smaller. Frame movement preferably results in simultaneous first and second force translator movement, coupling the first force translator400to the drive mechanism300in the first position and decoupling the first force translator400from the drive mechanism300in the frame's second position. Alternatively, frame movement can result in first and second reciprocating pump movement relative to the drive mechanism300, wherein the frame242statically connects the positions of the first and second pump chambers. However, the force translators can be otherwise connected and disconnected to the drive mechanism300. The frame242can additionally include features, such as arcuate grooves on the surface of the frame proximal the drive mechanism, which facilitate second force translator slip relative to the bearing surface. The fluid manifold preferably fluidly connects the reservoir20to an inlet of the second pump, but can additionally fluidly connect the reservoir20to an inlet of the first pump. In the latter alternative, the valve260is preferably located upstream of the junction between the three fluid connections or within the junction. In this latter alternative, valve opening simultaneously floods both lumens of the first and second reciprocating pumps. Because second reciprocating pump preferably has a larger pressurization area than the first reciprocating pump, the second reciprocating pump preferably exerts a linear (e.g., radial) decoupling force on the frame242when pressurized, which is transferred by the frame242into a shift in the position of the first force translator400away from the drive mechanism300, effectively decoupling the first force translator400from the drive mechanism300(as shown inFIG. 9B).