Patent ID: 12258959

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

In the following description, and for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the various aspects of the invention. It will be understood, however, by those skilled in the relevant arts, that the present invention may be practiced without these specific details. In other instances, known structures and devices are shown or discussed more generally in order to avoid obscuring the invention. In many cases, a description of the operation is sufficient to enable one to implement the various forms of the invention. It should be noted that there are many different and alternative configurations, devices and technologies to which the disclosed inventions may be applied. Thus, the full scope of the invention is not limited to the examples that are described below.

As used herein, the term “valve head” refers to a movable rigid structure that either gives the sealing structure, such as a valve ball or a seal flap, space to move or moves into contact with the sealing structure to keep the sealing structure in contact with the valve seal. The valve head can be made of metal or plastic, but must be a rigid component.

“Valve ball” refers to a spherical object such as a Delrin ball. The valve ball may be made of other materials known in the art. The ball has a low mass so that it can be moved easily by fluid flow through the valve.

“Valve flap” refers to a structure formed from an elastomeric that is non-permeable, such as a flexible and resilient rubber or rubber-like compound including but not limited to silicon rubber. The valve flap may be made out of other suitable materials known in the art. The valve flap has sufficient flexibility to be deflected by fluid flow, but sufficient rigidity to maintain its general shape when deflected and to return to its original shape when not deflected by fluid flow.

“Valve seal” also refers to a structure formed from an elastomeric that is non-permeable, such as a flexible and resilient rubber or rubber-like compound including but not limited to silicon rubber. The valve seal includes a centrally located aperture through which fluid can flow when the valve seal is not closed by a valve flap or a valve ball.

With reference now to the drawings in which like reference characters designate like or similar parts throughout the several views,FIGS.1A-1Dillustrate a first embodiment of a bi-directional self-energizing valve, generally indicated at100, in various states of operation in accordance with the principles of the present invention. The valve100is comprised of a valve body102within which is contained a valve head104, a valve closing member in the form of a valve flap106and valve seal108. The valve body102includes a fluid inlet110and a fluid outlet112. The valve head104resides within a cylinder wall114and is vertically movable within the space116defined by the cylinder wall114. The valve seal108resides above the inlet110and includes a central aperture120that is arranged concentrically with the inlet110so that fluid flowing through the inlet can flow through the central aperture120. The valve seal108is retained on its outer perimeter122by a seal recess124formed within the valve body102. The valve flap106is held one end126to the valve body102with a portion of the valve flap106positioned within a valve flap recess128within the valve body102.

As shown inFIG.1A, the valve head104holds the valve flap106over the valve seal108to thereby create a seal between the valve seal108and the valve flap106. This first valve state prevents a flow of fluid from the inlet110to the outlet112. As the inlet pressure increases, as shown inFIG.1B, with the valve head still in contact with the upper surface130of the valve flap106, due to the pressure differential between the inlet110and the outlet112and the flexible and resilient nature of the valve seal108and valve flap106, in this second valve state the valve seal108is upwardly forced into the valve flap106, effectively increasing the strength of the seal between the valve seal108and the valve flap106in proportion to the pressure differential between the valve inlet110and the valve outlet112.

As shown inFIG.1C, a third valve state occurs when the valve head104is lifted relative to the valve flap106. When the inlet pressure is greater than the outlet pressure, as the valve head104is lifted, the proximal end132of the valve flap106is upwardly forced by fluid pressure toward the valve head104. This allows fluid flow (as represented by arrows) through the inlet110, through the aperture120of the valve seal108into the inner valve chamber134defined by the valve body102and out the outlet112.

As shown inFIG.1D, however, when the valve head104is still in a lifted position relative to the valve flap106and the inlet pressure drops below the outlet pressure, the pressure differential between the outlet112will force the valve flap106into contact with the valve seal108, thereby sealing the aperture120of the valve seal108. This movement of the valve flap106is further enhanced by the Bernoulli principle. The Bernoulli effect will initially cause the valve flap106to quickly move to the seal aperture120in the event of a reverse flow through the valve100. In this fourth valve state, the engagement of the valve flap106with the valve seal prevents back flow through the outlet112and into the inlet110when the outlet pressure exceeds the inlet pressure. As the outlet pressure increases, the strength of the seal between the valve flap106and the valve seal108increases proportionately. As such, the valve flap106in combination with the valve seal108thus provide a bi-directional self-energizing seal for the bi-directional self-energizing valve100.

FIGS.2A-2Dillustrate a second embodiment of a bi-directional self-energizing valve, generally indicated at200, in various states of operation in accordance with the principles of the present invention. The valve200is comprised of a valve body202within which is contained a valve head204, a valve closing member in the form of a valve ball206and valve seal208. The valve body202includes a fluid inlet210and a fluid outlet212. The valve head204resides within a cylinder wall214and is vertically movable within the space216defined by the cylinder wall214. The valve seal208resides above the inlet210and includes a central aperture220that is arranged concentrically with the inlet210so that fluid flowing through the inlet can flow through the central aperture220. The valve seal208is retained on its outer perimeter222by a seal recess224formed within the valve body202. The valve ball206is a bi-directional sealing member that performs a similar bi-directional sealing function as the valve flap106shown and described with reference toFIGS.1A-1D. The valve ball206is positioned within an inner valve chamber234defined by the valve body202that is in fluid communication with both the inlet210and outlet212of the valve body202.

As shown inFIG.2A, the valve head204holds the valve ball206over the valve seal208to thereby create a seal between the valve seal208and the valve ball206. This first valve state prevents a flow of fluid from the inlet210to the outlet212. As the inlet pressure increases, as shown inFIG.2B, with the valve head204still in contact with the upper surface230of the valve ball206, due to the pressure differential between the inlet210and the outlet212and the flexible and resilient nature of the valve seal208and valve ball206, in this second valve state the valve seal208is upwardly forced into the valve ball206, effectively increasing the strength of the seal between the valve seal208and the valve ball206in proportion to the pressure differential between the valve inlet210and the valve outlet212.

As shown inFIG.2C, a third valve state occurs when the valve head204is lifted relative to the valve ball206. When the inlet pressure is greater than the outlet pressure, as the valve head204is lifted, the valve ball206is upwardly forced by fluid pressure toward the valve head204. This allows fluid flow (as represented by arrows) through the inlet210, through the aperture220of the valve seal208into the inner valve chamber234and out the outlet212.

As shown inFIG.2D, however, when the valve head204is still in a lifted position relative to the valve ball206and the inlet pressure drops below the outlet pressure, the pressure differential between the outlet212will force the valve ball206into contact with the valve seal208, thereby sealing the aperture220of the valve seal208. This movement of the valve ball206is further enhanced by the Bernoulli principle. The Bernoulli effect will initially cause the valve ball206to quickly move to the seal aperture220in the event of a reverse flow through the valve200. In this fourth valve state, the engagement of the valve ball206with the valve seal prevents back flow through the outlet212and into the inlet210when the outlet pressure exceeds the inlet pressure. As the outlet pressure increases, the strength of the seal between the valve ball206and the valve seal208increases proportionately. As such, the valve ball206in combination with the valve seal208thus provide a bi-directional self-energizing seal for the bi-directional self-energizing valve200.

In order for the valve100shown and described with reference toFIGS.1A-1Dto operate, the valve head104must be selectively and precisely actuated between a first position where the valve100is forced to a closed position and a second position where the valve100can open if the valve inlet pressure exceeds the valve outlet pressure. As shown inFIGS.3A-3D, the basic valve configuration of the valve100shown and described with reference toFIGS.1A-1Dhas been incorporated into a mechanically actuated valve300. The valve is a bi-directional self-energizing valve and is shown in various states of operation in accordance with the principles of the present invention. The valve300is comprised of a valve body302within which is contained a valve head304, valve flap306and valve seal308. The valve body302includes a fluid inlet310and a fluid outlet312. The valve head304resides within a cylinder wall314and is vertically movable within the space316defined by the cylinder wall314. The valve seal308resides above the inlet310and includes a central aperture320that is arranged concentrically with the inlet310so that fluid flowing through the inlet can flow through the central aperture320. The valve seal308is retained on its outer perimeter322by a seal recess324formed within the valve body302. The valve flap306is held one end326to the valve body302with a portion of the valve flap306positioned within a valve flap recess328within the valve body302.

As shown inFIG.3A, the valve head304comprises a vertically movable piston body304′ that defines a circumferential groove305for receiving and retaining an O-ring307to seal the piston body304′ to the cylinder wall314as the piston body304′ translates between first and second positions as illustrated inFIGS.3A-3D. The valve head304further includes a cam head309positioned within a cam chamber311. The cam head309is biased into contact with a rotatable cam315positioned above the cam head309with a biasing device317, such as a coil spring, that extends between the underside319of the cam head and a floor321of the cam chamber. The biasing device317forces the valve head304toward the cam315and away from the valve flap306.

In the closed position as illustrated inFIG.3A, the lower end of the valve head304holds the valve flap306over the valve seal308to thereby create a seal between the valve seal308and the valve flap306. This first valve state prevents a flow of fluid from the inlet310to the outlet312. As the inlet pressure increases, as shown inFIG.1B, with the valve head304still in contact with the upper surface330of the valve flap306, due to the pressure differential between the inlet310and the outlet312and the flexible and resilient nature of the valve seal308and valve flap306, in this second valve state the valve seal308is upwardly forced into the valve flap306, effectively increasing the strength of the seal between the valve seal308and the valve flap306in proportion to the pressure differential between the valve inlet310and the valve outlet312.

As shown inFIG.3C, a third valve state occurs when the valve head304is lifted relative to the valve flap306. This occurs as the cam315is rotated so that the upper surface323of the cam head309engages at least partially with the second cam surface315″. The second cam surface315″ has a shorter radius from a center of rotation of the cam315than the first cam surface315′. When this occurs, the valve head304moves away from the valve flap306. When the inlet pressure is greater than the outlet pressure, as the valve head304is lifted, the proximal end332of the valve flap306is upwardly forced by fluid pressure toward the valve head304. This allows fluid flow (as represented by arrows) through the inlet310, through the aperture320of the valve seal308into the inner valve chamber334defined by the valve body302and out the outlet312.

As shown inFIG.3D, however, when the valve head304is still in a lifted position relative to the valve flap306, which may be when the cam315is rotated so that the upper surface323of the cam head309engages at least partially with the second cam surface315″, and the inlet pressure drops below the outlet pressure, the pressure differential between the outlet312will force the valve flap306into contact with the valve seal308, thereby sealing the aperture320of the valve seal308. This movement of the valve flap306is further enhanced by the Bernoulli principle. The Bernoulli effect will initially cause the valve flap306to quickly move to the seal aperture320in the event of a reverse flow through the valve300. In this fourth valve state, the engagement of the valve flap306with the valve seal prevents back flow through the outlet312and into the inlet310when the outlet pressure exceeds the inlet pressure. As the outlet pressure increases, the strength of the seal between the valve flap306and the valve seal308increases proportionately. As such, the valve flap306in combination with the valve seal308provides a bi-directional self-energizing seal for the bi-directional self-energizing valve300.

Similarly, in order for the valve200shown and described with reference toFIGS.2A-2Dto operate, the valve head204must be selectively and precisely actuated between a first position where the valve200is forced to a closed position and a second position where the valve200can open if the valve inlet pressure exceeds the valve outlet pressure. As shown inFIGS.4A-4D, the basic valve configuration of the valve200shown and described with reference toFIGS.2A-2Dhas been incorporated into a mechanically actuated valve400. The valve is a bi-directional self-energizing valve and is shown in various states of operation in accordance with the principles of the present invention.

The valve400is comprised of a valve body402within which is contained a valve head404, valve ball406and valve seal408. The valve body402includes a fluid inlet410and a fluid outlet412. The valve head404resides within a cylinder wall414and is vertically movable within the space416defined by the cylinder wall414. The valve seal408resides above the inlet410and includes a central aperture420that is arranged concentrically with the inlet410so that fluid flowing through the inlet can flow through the central aperture420. The valve seal408is retained on its outer perimeter422by a seal recess424formed within the valve body402. The valve ball406is a bi-directional sealing member that performs a similar bi-directional sealing function as the valve flap306shown and described with reference toFIGS.3A-3D. The valve ball406is positioned within an inner valve chamber434defined by the valve body402that is in fluid communication with both the inlet410and outlet412of the valve body202.

As shown inFIG.4A, the valve head404comprises a vertically movable piston body404′ that defines a circumferential groove405for receiving and retaining an O-ring407to seal the piston body404′ to the cylinder wall414as the piston body404′ translates between first and second positions as illustrated inFIGS.4A-4D. The valve head404further includes a cam head409positioned within a cam chamber411. The cam head409is biased into contact with a rotatable cam415positioned above the cam head409with a biasing device417, such as a coil spring, that extends between the underside419of the cam head and a floor421of the cam chamber. The biasing device417forces the valve head404toward the cam415and away from the valve ball406.

In the closed position as illustrated inFIG.4A, the lower end of the valve head404holds the valve ball406over the valve seal408to thereby create a seal between the valve seal408and the valve ball406. This first valve state prevents a flow of fluid from the inlet410to the outlet412. As the inlet pressure increases, as shown inFIG.4B, with the valve head404still in contact with the upper surface430of the valve flap406, due to the pressure differential between the inlet410and the outlet412and the flexible and resilient nature of the valve seal408and valve ball406, in this second valve state the valve seal408is upwardly forced into the valve ball406, effectively increasing the strength of the seal between the valve seal408and the valve ball406in proportion to the pressure differential between the valve inlet410and the valve outlet412.

As shown inFIG.4C, a third valve state occurs when the valve head404is lifted relative to the valve seal408. This occurs as the cam415is rotated so that the upper surface423of the cam head409engages at least partially with the second cam surface415″. The second cam surface415″ has a shorter radius from a center of rotation of the cam415than the first cam surface415′. When this occurs, the valve head404moves away from the valve flap406. When the inlet pressure is greater than the outlet pressure, as the valve head404is lifted, the valve ball406is upwardly forced by fluid pressure toward the valve head404. This allows fluid flow (as represented by arrows) through the inlet410, through the aperture420of the valve seal408into the inner valve chamber434defined by the valve body402and out the outlet412.

As shown inFIG.4D, however, when the valve head404is still in a lifted position relative to the valve seal408such that valve ball406is not forced into engagement with the valve seal408, which may be when the cam415is rotated so that the upper surface423of the cam head409engages at least partially with the second cam surface415″, and the inlet pressure drops below the outlet pressure, the pressure differential between the outlet412will force the valve ball406into contact with the valve seal408, thereby sealing the aperture420of the valve seal408. This movement of the valve ball406is further enhanced by the Bernoulli principle. The Bernoulli effect will initially cause the valve ball406to quickly move to the seal aperture420in the event of a reverse flow through the valve400. In this fourth valve state, the engagement of the valve ball406with the valve seal prevents back flow through the outlet412and into the inlet410when the outlet pressure exceeds the inlet pressure. As the outlet pressure increases, the strength of the seal between the valve ball406and the valve seal408increases proportionately. As such, the valve ball406in combination with the valve seal408provides a bi-directional self-energizing seal for the bi-directional self-energizing valve400.

As shown inFIGS.5A-5C, a basic valve configuration of the valve100shown and described with reference toFIGS.1A-1Dhas been incorporated into a mechanically actuated valve500. The valve500is a bi-directional self-energizing valve and is shown in various states of operation in accordance with the principles of the present invention. The valve500is comprised of a valve body502within which is contained a two-piece valve head504′ and504″, valve flap506and valve seal508. The valve body502includes a fluid inlet510and a fluid outlet512. The two-piece valve head504′ and504″ resides within a cylinder wall514and is vertically movable within the space516defined by the cylinder wall514. The valve seal508resides above the inlet510and includes a central aperture520that is arranged concentrically with the inlet510so that fluid flowing through the inlet can flow through the central aperture520. The valve seal508is retained on its outer perimeter522by a seal recess524formed within the valve body502. The valve flap506is held one side526to the valve body502with a portion of the valve flap506positioned within a valve flap recess528within the valve body502.

Interposed between the two sections of the two-piece valve head504′ and504″ is a head seal507. The valve body502defines a circumferential groove505for receiving and retaining an outer perimeter of the head seal507to seal cam chamber511and cam515from the valve chamber534. As the cam515rotates between a closed position as shown inFIG.5Ato an open position as shown inFIG.5B, the two sections504′ and504″ are moved in unison relative to the valve body502. Because the valve head seal507is interposed between the two sections504′ and504″ of the valve head, the valve head seal507is upwardly flexed relative to the valve body502as the lower valve head section504″ is lifted away from the valve flap506by spring517. In this position, a flow of fluid (represented by arrows) can flow through the inlet510past the valve flap506and out the outlet512.

As shown inFIG.5C, if the outlet pressure exceeds the inlet pressure, the valve flap506will return to a closed position due to the pressure applied by the outlet to the top surface of the valve flap506to cause the valve flap506to seal against the valve seal522. That is, the valve flap506will return to its closed position even though the cam515and thus the valve head504′ and504″ is in an open position.

In order to maintain a sterile valve chamber during operation of a valve in accordance with the present invention, as shown inFIG.6A, a valve600comprises one or more additional seals on the various moving components. The valve600is comprised of a valve body602having an inlet port604and an outlet port606. A valve head608is driven toward a valve ball610by the cam612as the cam rotates. When the valve ball610is forced into contact with the valve seal614, flow from the inlet port604through the valve600is prevented. It should be noted that the valve600is a generally cylindrical structure, with the various seals shown in cross-section. Thus, the seal614is a circular disc-shaped structure defining a central cylindrical aperture616. Likewise, a slide O-ring seal618extends around the lower end608′ of the valve head608and maintains a seal around the valve head608as the valve head608vertically reciprocates, first by being driven toward the valve seal614when the cam612is in the position as shown and second when it is retracted toward the cam612by the coil spring620when the cam612is rotated at 180 degrees. The slide O-ring seal618is maintained in position relative to the valve body602by being positioned between a slide seal retainer622that is positioned directly above the slide O-ring seal618and the valve seal retainer624that is positioned directly below the slide O-ring seal618. The valve seal retainer defines a cylindrical valve chamber626between the valve seal614and the lower end608′ of the valve head608. The ball valve610is sized to fit within the valve chamber626and to be freely vertically movable within the valve chamber626when the valve head608is in the lifted valve open position. The valve seal614resides between a lower wall surface628of the valve seal retainer and an upper wall surface630defined by the valve body602. A lower O-ring seal632is positioned below the valve seal614and provides an additional seal between the bottom surface of the valve seal614and the valve body602so that fluid in the valve chamber626cannot flow around the valve seal614and into the inlet604when the valve chamber pressure exceeds the inlet pressure. The lower O-ring seal also gives increased compliance to the valve seal614when the valve head608is pushed down by the cam612. For example, if the valve seal is 0.030 thick silicon rubber and is compressed 20%, only 0.006 inch of the valve seal is compress, which is a rather tight tolerance. With the O-ring in place, the tolerance is increase. For example, if the valve seal is 0.030 inch thick and the O-ring is 0.07 inch thick, the total thickness of the two seals combined is 0.100 inch. A 20% compression of 0.100 inch seal material is 0.02 inch, which is a much less difficult to achieve in such a valve system. In addition, rotary seals may be placed on the cam shaft to prevent contamination of the valve during operation. Such additional seals can be employed to create a sterile environment for both the inlet and outlet sides of the valve.

Moreover, as shown inFIG.6B, when the inlet pressure is higher than the outlet pressure and the valve600is mechanically closed by the cam612. The inlet pressure pushes the valve seal614up into the valve ball610, thus energizing that seal. The valve seal614is also being pushed up into the wall628. Thus, even though there is a gap between the wall630and the valve seal614, the valve seal614is still sealing to the ball valve610. Conversely, as shown inFIG.6C, when the outlet pressure is higher than the inlet pressure and the valve600is mechanically closed. The outlet pressure pushes the ball valve610down into the valve seal614thus energizing the seal between the valve ball610and the valve seal614. Also, the outlet pressure pushes the valve seal614into the lower wall630and thus the seal between the valve seal614and the wall630is energized. The result is that the gap between the wall628and wall630does not need to be a precise tolerance. This greatly reduces manufacturing costs. It also allows the valve seal614to be undeformed, as compared to when the valve seal is compressed between the two walls628and630, and thus highly predictable.

The valve600can thus be constructed by inserting the valve seal614into the valve body. The valve seal retainer624, which may comprise a cylindrical body having a central bore and a recessed peripheral groove and an outlet port in fluid communication between the central bore and the peripheral groove, is pressed into the valve body602with a press fit sufficient to retain the valve seal retainer624in place as well as make a seal between the valve body602and the valve seal retainer624. The peripheral groove around the outside of the valve seal retainer624allows it to be installed at any rotation and still be in fluid communication with the outlet606of the valve body602.

The valve seal retainer624is positioned 0.001 in to 0.01 inches above the valve seal614. The valve ball610is dropped into place and the sliding seal618is inserted. The slide seal retainer622is then pressed into place. It is press fit to hold it in place. The valve head608is then slid into the slide seal retainer622and the sliding seal618. The cam612is then slid into place.

As such, the valve seal614can be constructed of a more rigid material or constructed as a composite with two soft outer layers and a rigid core. Such a valve seal construction can withstand higher pressure.

The valves of the present invention are sufficiently inexpensive to manufacture and sufficiently low in energy consumption to operate that such valves can be incorporated into a system that is capable of operating on low power batteries.

The various components of the valves of the present invention may be comprised of plastic, metal or other materials known in the art. The ball valves may be comprised of acetyl ball valves and the piston may be comprised of Delrin rod. Regardless of the materials, however, the drug pump of the present invention is configured to be so inexpensive to manufacture that it can be disposable. The valves could be used for medical and nonmedical applications.

By way of example and not of limitation, the valves of the present invention could be incorporated into a pump.FIG.7Aillustrates such a pump, generally indicated at700in accordance with the principles of the present invention. The pump700is comprised of two valve assemblies710and720. The valve assemblies710and720are identically configured and as previously described with reference to valve300shown and described with reference toFIGS.3A-3D, but could be modified to include any of the valves ofFIGS.1A-6Bor combinations thereof. The valve710includes a cam712and the valve720includes a cam722. The cams712and722are oriented at 180 degrees from one another so that, as will be described in detail herein, when the valve710is in the open position the valve720is in the closed position and when the valve720is in the open position, the valve710is in the closed position. At the beginning of the pump cycle as shown inFIG.7A, both cams712and722are in a closed position such that the valve heads714and724, respectively, are in contact with their respective valve flaps716and726. The outlet718of the valve710is coupled to and in fluid communication with pump piston cylinder730. The pump piston cylinder730houses a pump piston732that is coupled a crank734with piston rod736. A crank seal738is provided around the crank734to seal the crank734. An electric motor740is coupled to the crank734and thus rotatably drives the crank734. The piston rod736is pivotally coupled to the crank734in an off center manner so that rotation of the crank causes reciprocal movement of the piston rod736and thus vertical movement of the piston732within the piston cylinder730. As will be described in more detail, the crank and cams712and722are timed so that they work in concert to draw fluid into the pump cylinder730when the piston is lowered, the valve710is open and the valve720is closed. To force the fluid drawn into the pump cylinder730through the valve720, the valve710is closed, the valve720is opened and the piston is raised within the piston cylinder730to force the fluid contained within the piston cylinder through the valve720. Repeating this cycle provides a precisely measured amount of fluid to flow through the pump700depending on the size of the piston cylinder and the rate at which the pump is cycled.

As shown inFIG.7B, as the crank734continues to rotate, the piston732is downwardly pulled. At the same time, the cam712of valve710is rotated in a clockwise direction so that the cam surface713begins to engage with the top surface715of the valve head714. As a result, the coil spring717forces the top surface715of the valve head714into contact with the cam surface713thereby causing the valve head714to lift relative to the valve flap716. As the valve flap716lifts from the valve seal721fluid (represented by arrows) is drawn through the inlet of the valve710, through the valve outlet and into the piston cylinder730. Because the valve720is still in a closed position, the fluid cannot flow through the inlet of the valve720that is in fluid communication with the piston cylinder730. Just as importantly, fluid at the outlet side of the valve720also cannot back flow into the valve cylinder730with the valve720in the closed position.

As the valve710continues to open as shown inFIG.7C, which represents the valve710in a fully open position, the flow of fluid continues to be drawn into the valve cylinder730until the piston732reaches its maximum displacement. As further shown inFIG.7D, when the piston732nears the bottom of its stroke, the cam712starts to move the valve head714toward the valve flap716. This movement of the valve head714causes any residual fluid between the valve head714and the valve flap716to be forced out the valve outlet718while simultaneously forcing the valve flap716into a closed position.

Continued rotation of the cam712causes the valve710to close, thus preventing any fluid to flow into the piston chamber730or fluid in the piston chamber730to flow back out the valve710as the piston732reaches is maximum displacement as shown inFIG.7E. In this stage of the pump cycle, the valve720is also in a closed position to continue to prevent the flow of fluid through the valve720until the piston732begins its positive stroke to pressurize the fluid in the piston chamber730thereby forcing the fluid contained in the valve chamber730into the inlet742of the valve720.

As the piston732is advanced into the piston chamber730as shown inFIG.7F, the cam722is rotated to simultaneously open the valve720as the piston732pressurizes the fluid in the piston cylinder730. The pressurized fluid enters the inlet742of the valve720and forces the valve flap726against the valve head as it is raised by the spring744. As further shown inFIG.7G, as the piston732continues its positive stroke, the valve720continues to open so that the fluid will continue to flow through the valve720.

As shown inFIG.7H, as the piston732continues to apply positive pressure to the fluid in the piston cylinder730, the valve720begins to close. The valve710also remains closed during this phase of the pump cycle. As the valve720begins to close, any fluid that exists between the valve head724and the valve flap726is forced through the outlet746of the valve720as well as fluid that is continued to be forced through the valve720by the piston732.

As shown inFIG.7I, at the end of the pump cycle, the valves710and720return to the starting position in which both valves are closed. The pump cycle then repeats through each of the valve cycle phases as described with reference to FIGS.7B-7I. Because the diameters of the valve heads and piston of the present invention are small, relatively high pressures can be accommodated. Despite being small, however, the pump system is capable of delivering significant volumes of fluid by rapid cycling of the pump system700.

FIG.8Aillustrates another embodiment of a pump, generally indicated at800in accordance with the principles of the present invention. The pump800is comprised of two valve assemblies810and820. The valve assemblies810and820are identically configured and as previously described with reference to valve400shown and described with reference toFIGS.4A-4D, but could be modified to include any of the valves ofFIGS.1A-6Bor combinations thereof. The valve810includes a cam812and the valve820includes a cam822. The cams812and822are oriented at 180 degrees from one another so that, as will be described in detail herein, when the valve810is in the open position the valve820is in the closed position and when the valve820is in the open position, the valve810is in the closed position. At the beginning of the pump cycle as shown inFIG.8A, both cams812and822are in a closed position such that the valve heads814and824, respectively, are in contact with their respective valve balls816and826. The outlet818of the valve810is coupled to and in fluid communication with pump piston cylinder830. The pump piston cylinder830houses a pump piston832that is coupled a crank834with piston rod836. A crank seal838is provided around the crank834to seal the crank834. An electric motor840is coupled to the crank834and thus rotatably drives the crank834. The piston rod836is pivotally coupled to the crank834in an off center manner so that rotation of the crank causes reciprocal movement of the piston rod836and thus vertical movement of the piston832within the piston cylinder830. As will be described in more detail, the crank and cams812and822are timed so that they work in concert to draw fluid into the pump cylinder830when the piston is lowered, the valve810is open and the valve820is closed. To force the fluid drawn into the pump cylinder830through the valve820, the valve810is closed, the valve820is opened and the piston is raised within the piston cylinder830to force the fluid contained within the piston cylinder through the valve820. Repeating this cycle provides a precisely measured amount of fluid to flow through the pump800depending on the size of the piston cylinder and the rate at which the pump is cycled.

As shown inFIG.8B, as the crank834continues to rotate, the piston832is downwardly pulled. At the same time, the cam812of valve810is rotated in a clockwise direction so that the cam surface813begins to engage with the top surface815of the valve head814. As a result, the coil spring817forces the top surface815of the valve head814into contact with the cam surface813thereby causing the valve head814to lift relative to the valve ball816. As the valve ball816lifts from the valve seal821fluid (represented by arrows) is drawn through the inlet of the valve810, through the valve outlet and into the piston cylinder830. Because the valve820is still in a closed position, the fluid cannot flow through the inlet of the valve820that is in fluid communication with the piston cylinder830. Just as importantly, fluid at the outlet side of the valve820also cannot back flow into the valve cylinder830with the valve820in the closed position.

As the valve810continues to open as shown inFIG.8C, which represents the valve810in a fully open position, the flow of fluid continues to be drawn into the valve cylinder830until the piston832reaches its maximum displacement. As further shown inFIG.8D, when the piston832nears the bottom of its stroke, the cam812starts to move the valve head814toward the valve ball716. This movement of the valve head814causes any residual fluid between the valve head814and the valve flap816to be forced out the valve outlet818while simultaneously forcing the valve ball816into a closed position.

Continued rotation of the cam812causes the valve810to close, thus preventing any fluid to flow into the piston chamber830or fluid in the piston chamber830to flow back out the valve810as the piston832reaches is maximum displacement as shown inFIG.8E. In this stage of the pump cycle, the valve820is also in a closed position to continue to prevent the flow of fluid through the valve820until the piston832begins its positive stroke to pressurize the fluid in the piston chamber830thereby forcing the fluid contained in the valve chamber830into the inlet842of the valve820.

As the piston832is advanced into the piston chamber830as shown inFIG.8F, the cam822is rotated to simultaneously open the valve820as the piston832pressurizes the fluid in the piston cylinder830. The pressurized fluid enters the inlet842of the valve820and forces the valve flap826against the valve head as it is raised by the spring844. As further shown inFIG.8G, as the piston832continues its positive stroke, the valve820continues to open so that the fluid will continue to flow through the valve820.

As shown inFIG.8H, as the piston832continues to apply positive pressure to the fluid in the piston cylinder830, the valve820begins to close. The valve810also remains closed during this phase of the pump cycle. As the valve820begins to close, any fluid that exists between the valve head824and the valve flap826is forced through the outlet846of the valve820as well as fluid that is continued to be forced through the valve820by the piston832.

At the end of the pump cycle, the valves810and820return to the starting position as shown inFIG.8Ain which both valves are closed. The pump cycle then repeats through each of the valve cycle phases as described with reference toFIGS.8B-8H. Because the diameters of the valve heads and piston of the present invention are small, relatively high pressures can be accommodated. Despite being small, however, the pump system is capable of delivering significant volumes of fluid by rapid cycling of the pump system800.

Referring now toFIG.9, there is illustrated a drug pump, generally indicated at900, in accordance with the principles of the present invention. The drug pump900is comprised of two valve assemblies910and920and a motor driven piston assembly930. The valve assemblies910and920and piston assembly930comprise a pump system that is similar to and operates in a similar manner to the pump system700shown and described with reference toFIGS.7A-7I, but could be modified to include any of the valves ofFIGS.1A-6Bor combinations thereof.

The input912of the valve910is coupled to and in fluid communication with a pressure sensor930. The pressure sensor930senses fluid pressure on the inlet line912′. A low pressure from the pressure sensor930may indicate a blockage in the line931to the IV bag932or that the IV bag932is empty.

In order to ensure that air bubbles are not injected into the patient, an air bubble removal chamber934is coupled to an outlet line936′ that is in fluid communication with outlet936of the valve920. The air bubble removal chamber comprises a gas permeable membrane through which air bubbles pass and through which the liquid in the system cannot. Thus, the air bubble removal chamber efficiently removes air from the fluid exiting the valve920before the fluid enters the patient P. In order to ensure that fluid is flowing through the air bubble removal chamber934, a pressure sensor938is coupled to the air bubble removal device. The pressure sensor938checks to ensure that fluid is flowing through the system. If only air is present, fluid pressure is not able to be built up in the air bubble removal chamber.

The system900also includes a pressure check valve940. The check valve940slightly elevates the pressure in the air bubble removal chamber thus making the air bubbles smaller and able to pass through the air bubble removal membrane more quickly. The check valve also prevents back flow of fluid from the patient P into the system900that could otherwise contaminate the pump. A pressure out sensor942is coupled to the check valve940. The pressure out sensor942senses fluid pressure on the outlet line944that is going to the patient P. A high pressure detected by the pressure out senor942indicates that the line to the patient may be blocked.

Referring now toFIG.10, there is illustrated a pump, generally indicated at1000, in accordance with the principles of the present invention. While the foregoing embodiments illustrate a pump in which the cams and crank shaft may be separate components separately driven by separate motors or by a single motor that is coupled to each component with a linkage, the present invention contemplates a combination crank shaft and cam assembly. In this embodiment, in order to ensure that the two cams1002and1004of the valves1003and1005, respectively, and the pump1008are precisely timed, a combination crank shaft and cam shaft1010is employed. The combination crank shaft and cam shaft is a combination crank shaft and cam shaft. The crank shaft portion1011of the combination crank shaft and cam shaft operates the piston1014in the pump chamber1016while the cam shaft portion1012of the combination crank shaft and cam shaft1010synchronizes the operation of the cams1002and1004of the respective valve assemblies1003and1005.

The pump1000is comprised of a pump housing1020to which an electric motor1022is coupled. The motor1022is coupled to and rotates the combination crank shaft and cam shaft1010. The speed of the motor1022, in combination with the cycle volume of the pump1000, dictates the volume of fluid that can be pumped. For example, if the single cycle pump volume is 0.05 ml, and the electric motor rotates the combination crank shaft and cam shaft at 20 rpm. The pump1000would deliver 1 ml of fluid per minute. The combination crank shaft and cam shaft1010is sealed to the housing1020with a toroidal combination crank shaft and cam shaft seal1022, which may be in the form of a sliding O-ring.

As shown inFIG.10, the pump is in a particular stage of operation. Here the inlet valve1005is in a closed position, with the valve head1024in contact with the valve seal1026and the outlet valve1003is in an open position with the valve head1028being forced away from the valve seal1030by the spring1032as allowed by the cam1002. The piston1014of the pump is being forced by the cam portion1011of the combination crank shaft and cam shaft into the pump chamber1016to force fluid contained in the pump chamber1016into the outlet valve1003.

The valves of the present invention can be inexpensively manufactured, while achieving highly accurate and reliable operation. As shown inFIGS.13and14, a central mechanism of valves in accordance with the present invention is a flexing seal constrained between two boundaries. The seal may be comprised of a rubber disc. Constrained flexing of the seal creates a two-state system in which the seal closes by flexing to be in contact with the head of the valve and opens by flexing to move away from the head of the valve. Hydrodynamics of this interaction power valve opening and closing, and hydrostatics power valve resistance to back pressure. As shown inFIG.13, the silicone rubber disc seal is shown in plan and cross-sectional views. The disc or seal is positioned into a casing as shown in cross-section inFIG.14. The disc edges are captured by the case as shown. A and B are ports that experience various pressures.

As shown inFIGS.15and16, a reaction of the seal to different pressure differentials is shown. InFIG.15, the pressure at A (P(A)) is greater than the pressure at B (P(B)). The pressure differential causes the seal to flex upward. However, since the edges of the seal are retained, it is not able to flex beyond the arrow that represents Max Up height. InFIG.16, P(B)>P(A), the seal is flexed down. Again, since the Seal is retained it can only flexed down to the Max Down height.

Flexing of a doubly constrained seal enables self-energizing check valves. As shown inFIGS.17and18, a flexible, doubly constrained seal provides a seal that is-self energizing. Self-energizing refers to a seal that uses the pressure differentials inside the valve to keep the seal pressed against another piece, referred to herein as the head. The self-energizing seal can occur in two ways as shown inFIGS.17-20. A simple valve that can be constructed using self-energizing seals as a check valve.

Check valves are driven by pressure and thus have no independent control.FIG.17shows a self-energizing check valve that closes when P(A)>P(B) and opens, as shown inFIG.19when P(B)>P(A). When closed, as the pressure differential of A over B increases, the force with which the seal contacts the ledge also increases. This seal will not leak until the pressure differential is so high that it ruptures the seal.

FIG.18shows a self-energizing check valve, analogous to a ball check valve. In this case a free-floating part, the head, has been added. If P(B)>P(A) then the seal flexes down towards its lower limit, but the head is also pushed down into the seal. As the pressure differential increases the head will push down into the seal with increasing force. Again, the seal will not leak until the pressure is high enough to rupture the seal. And, when P(A)>P(B), the ball is pressed upward, as shown inFIG.20, as is the seal, and the valve opens.

In a prior art direct force valve, the pressure on the seal is provided by an external control transmitted through the head. The direct force between the seal and the head is independent of the differential pressure and does not vary with pressures A and B. As the hydraulic fluid pressure differential P(B)>P(A) increases to the level of pressure to which the head is tightened, the fluid will creep in between the ledge and the seal and it will compress the seal and push up on the head until it makes a path to start leaking. Similarly, as pressure differential P(A)>P(B), becomes larger than the external force transmitted through the head to the seal, fluid will start to leak in the opposite direction. This type of valve always has to be sealed with the maximum force necessary to ensure against leaking at the maximum possible pressure differential, even when the typical system pressure differential is low.

Conversely, a self-energizing seal reduces energy required to maintain a valve sea. This is important in controlled sealing such as when controlling a pump or actuator. For example, a direct force seal to control a valve in a pump that may be required to seal 1000 psi that is only operating at 100 psi may require 5 lbs. of force to close even though at 100 psi only 0.5 lbs. may be required. A direct force valve must always seal against maximum possible pressure. Similarly, if a direct force valve is cycling at 4000 RPM, the pump valve is may be using 377 W for one valve. Further, there is usually two valves so that the total of 753 W, which is nearly 1 horse power, may be required.

A self-energizing valve would not require any external force energy to seal. The only energy it would use would be the energy to overcome friction of moving the head. This is a dramatic reduction for system with high oscillations, and/or high number of valves. In addition, self-energizing seals increase safety and reliability of the valve. The self-energizing seals of the present invention will not leak until the pressure is so high that it ruptures the system. This is a dramatic increase in safety of the system.

The present invention uses doubly constrained valve heads with doubly constrained self-acting seals to make controllable valves. To make controllable valves using doubly constrained self-acting seals, one needs for the seal to interact with a second part, the valve head, which also has two boundaries and an intermediate stop. The top boundary is the head above any contact with the seal. The intermediate stop is the point of contact between the head and the seal in an up position. A soft bottom boundary is where the head follows the seal from the intermediate stop up to the full down seal position. Setting control stops for the head using these three positions leads to four control conditions for the head. The four control conditions for the head are”

Open: Head LOCKED in UP position (FIG.21)

Closed: Head bounded in INTERMEDIATE Position FREE to follow seal to DOWN position (FIG.22)

Check Valve B to A: Head LOCKED in INTERMEDIATE position (FIG.23)

Check Valve A to B: Head FREE RANGE from UP position to DOWN position (FIG.24)

As shown inFIG.25, hydrodynamics powers the opening and closing of the control valve. In conventional valves, all of the energy required to open or close the valve must be supplied through the control system. In valves of the present invention, the only energy supplied through the control system is that required to reset the boundaries on the valve head. The actual movement of the head is powered by differential pressure and hydrodynamics. As a result, valves don't need nearly as much energy. The opening and closing have different flow scenarios, with the hydrodynamics of opening and closing will be discussed individually herein.

The following terms may be used to mean as follows:

Opening Flow: When a valve is opening, the flow is starting at zero and then accelerating.

Closing Flow: When a valve is closing, there is already an established flow and flow pattern is being shut off. The opening and closing flow patterns, create different forces on the head and seals. If the control moves the head quickly to the correct location, the forces from these two patterns will assist the control. This is demonstrated below.

Valve:FIG.25shows a valve without control being implemented. A description of its components is given below.

Casing: A block of material with a hole in it (white area) and a port A and B.

Seal: is a compliant material such as silicone rubber. For higher pressure it can be backed with spring steel or other. It can also be a more rigid seal that slides up and down between two stops. It may be a rubber disc with a hole in the center.

Head: Usually a ridged material like stainless steel or plastic but could be a compliant material such as a silicone rubber ball or flap.

Control: The control is a mechanism that controls the movement of the head up and down. It could be a camshaft, crankshaft, servo-motor, screw, stepper motor, linear motor, wedge, lever, or other device. InFIG.25, the control is shown as a dotted line circle.

As shown inFIG.26, a rigid wall, a rigid wall connected to the head and a rigid wall that limits a maximum height of the head are illustrated.

FIG.27includes four stages of a valve showing the steps for opening the valve when P(A)>P(B). The pressure at A in the valve is greater than the pressure at B. Thus, the differential pressure is trying to push the head up. If the pressure differential is high then this force is enough to snap the valve open, which is desirable when the pressure differential is high. When the pressure differential is low, then opening is already low energy. The low differential will still help open the valve, but more importantly the valve will not resist opening.

Step1shows the valve closed, P(A)>P(B). Thus, the P(A) is pushing up on the bottom of the head trying to open the valve.

In step2, the rigid wall control is removed, and the head rapidly accelerates upward due to the pressure differential P(A)>P(B). Since the flow is still establishing, P(A) is still pushing up on the Head.

In step3, the flow is still establishing, and the Head is at its top position at which time the Control rigidly locks the Head in the shown position.

In step4, the flow is established, and the Control has the Head locked in place (Mode3a) the flow is traveling with a velocity across the bottom of the Head and flow isn't traveling to the top of the Head. Thus, in this case a Bernoulli affect exists creating a low pressure on the bottom of the Head. The valve wants to close, but the Control has already locked the Head into place, so it can't close. This final step is analogous to a spring being cocked. The moment the control in step4releases the head, it wants to close, or at low flows it at least does not resist closing.

FIG.28shows the steps for closing the valve when P(B)>P(A).

In step1, there is already an established flow B to A and thus there is already an established Bernoulli effect in place due to the flow across the bottom surface of the head. The pressure differential is trying to push the head down, but the control has the head held in place.

In step2, the control releases the head and the head rapidly moves downward to the shown position.

In step3, the control places the rigid wall such that the maximum height of the head is restricted as shown.

In step4, the Bernoulli effect creating a low pressure under the head as well as the fact that P(B)>P(A), force the head down into the seal. Only mode2is acceptable for closing the valve in this scenario.

FIG.9shows a valve closing in four steps when P(A)>P(B).

In step1, there is already an established flow across the bottom of the Head and thus there is a Bernoulli effect in place that creates a low pressure on the bottom of the head. The valve is trying to close but is held in place by the control.

In step2, the control releases the head and the head rapidly moves to the shown.

In step3, the control places the rigid wall as shown so the head can't move upward. Both Mode1and Mode2are appropriate.

In step4, the Bernoulli effect and the pressure differential P(A)>P(B) cause the head and the seal to suck together in a snap like action. Once together the pressure differential P(A)>P(B), pushes the seal into the head. The seal is now a self-energized seal. P(A) is trying to open the valve, but the control already has the head locked into place in either Mode1or Mode2.

As shown inFIG.30, a four-mode valve according to the present invention may be actuated with two camshafts that are rotated directly or indirectly by solenoids, servo-motors, hydraulics, pneumatics, or other devices or systems known in the art. A camshaft is a shaft with cuts in it such that when the shaft turns the cuts face different directions and change the surface the follower can push against. The solid part of the Cam is shown in black. Note that CAM1has two positions whereas CAM2is a 3-position camshaft.

As shown inFIG.31, the camshafts are on the inside of the valve body. In this case the two camshafts pass into and out of the valve body through rotary seals (not shown). Note that the position of the Camshafts has been reversed fromFIG.30.

FIG.32illustrates a two-mode valve that only requires control providing the equivalent information of one camshaft, and is thus more simple to control than a four-mode valve, require less volume, and is significantly less expensive than four-mode valves in pump and actuator applications.

The valve shown inFIG.32uses only Mode2and Mode4of the Head controls. The valve has the following characteristics:

a. When mechanically closed, the Seals are Self-Energizing in both directions. (A>B & B>A). This prevents free flow conditions.

b. When open, the valve acts as a check valve that only allows flow A to B. This prevents any reverse flow in the system.

c. Low energy opening and low energy closing. Makes it possible to lower the pump power consumption, which facilitates mobile applications.

d. Inexpensive and simple to manufacture.

Only has two input controls. Closed or open with check valve always A to B.

e. Positive close. When the control closes the valve, it is closed. This is an important function in high risk valve situations such as drug pumps.

As mentioned, the pump only requires Mode2and Mode4. As shown inFIG.32, the control can be achieved by varying only the limits on the upward maximum position of the Head. The pump valve uses the seal that can flex both directions, but it does not require the downward flex. It only requires the upward flex. Mode2band Mode4abelow show the situation where P(B)>P(A). The Head moves into the membrane. If the membrane didn't flex down, it would still work and the membrane flexing down as in P(B)>P(A) cases, does not effect the system. The head just moves a little farther down.

FIG.33shows a simplified version of a Valve. This valve uses Model and Mode3of the valve. This valve is:

A. Low energy opening and low energy closing. This is important especially if there are many actuators such as in digital hydraulics.

B. When closed and P(A)>P(B) it has self-energizing seals A to B

C. When the control is in the closed position but P(B) is greater than P(A) then it is a check valve that allows flow from B to A. In actuator control this prevents an external perturbation of the actuator from driving the actuator over the Supply pressure of the system.

D. When open it does not have a closed state.

E. Inexpensive and simple to manufacture.

As mentioned earlier, this valve only uses Mode1and Mode3. The diagrams inFIG.33show the Head rigidly attached to the control.

InFIG.34, the Actuator Valves operates in 2 modes, each mode has 2 states shown in the 4 diagrams. The Actuator Valve does require the seal to flex both up and down. The flex up is shown in Model a where P(A)>P(B). The flex down is shown in Mode1bwhere P(B)>P(A).

FIG.35illustrates a Pump valve. The Pump valve is a simplified version of the 4Mode Valve and allows for:

A. The removal of the need to lock the Head

B. It removes the lower control cam (or similar control device)

C. It allows the head to be a free-floating ball (or other shape device)

D. It allows the control wall to just be a rod pushed through a sliding seal (or one of the other shown simple devices)

E. It does not require a bi-direction flex seal, but can still use it.

As shown inFIG.35, a Rod slides through seals. This allows the Control of the valve to be external to the Valve body. It should be appreciated that other mechanisms could be used to accomplish this such as rotary seals, diaphragms, and other.

As shown inFIG.36, a Pump valve is operated by a single two-position camshaft (Cam1). The rod is shown with a normal diameter passing through a sliding seal. The spring is used to overcome the friction of the sliding seal and push the rod up against the cam. The Head is a ball.

As shown inFIG.37, the ball of the Pump valve ofFIG.36has been replaced by a flap. In the far left version, the flap is actuated by the rod that slides up and down. The two versions to the right show the flap actuated by a camshaft in direct contact with the flap.

As shown inFIG.38, the valve Head is a ball in direct contact with a camshaft. The camshaft passes into and out of the valve cavity through a set of rotary seals (not shown). A flap in direct contact with the camshaft shown inFIG.37can also be used with the ball as shown below.

Although some of the illustrated embodiments show valve configurations that can be assembled from one direction, this is not necessary. The valves can be configured to be assembled from multiple direction. As shown inFIG.39, the valve on the left is assembled from the top. The valve on the right is assembled from the bottom and top.

The valves as shown and described herein, can be adapted for various pumps, both large and small, since the valves have a very small dead volume and a piston head can be brought very close to the valve. This is important since dead volume limits the size of the vacuum a pump can draw and also causes the flow to roll off as back pressure increases. As shown inFIG.40, a drug pump uses two pump valves. The dead volume is relatively small because the piston head comes up into the valve area. The piston head PH is pointed. It starts to penetrate the bottom of the output valve O and could actually be formed to take up more dead space. Note that the dead volume is just the port P from the ball to the tip of the piston head. It should be appreciated that the piston head could have an extended tip piece that fills the port P to take up the majority of the dead volume. Also, the dead area of the intake valve I is also small. It is the volume of the port from the piece to the piston head. It also includes the minimal area around the ball.

As shown inFIG.41, the Actuator Valve lends itself well to digital hydraulics. In digital hydraulics, when the valve opens flow occurs both directions. When it closes it remains closed with a check valve that allows flow from B to A. InFIG.41, only State1and3are utilized. The Actuator Valve is shown with a possible control mechanism for states1and3only. The valve only requires actuation up. Also, in this valve CAM2is reduced to a two-position camshaft.

As shown inFIG.42, the valve has the same modes as the above valve, but has a change to a snap closed valve. Here, the Rod and Head have been replaced with a single rod. This means there is no hydraulic pressure on the top side of the rod to push the rod shut since the rod passes through the sliding seal out of the valve chamber. However, the Seal still experiences the Bernoulli force and can be snapped up into the rod. Thus, it still has the ability to snap closed, but it will be slightly less snappy than the valve ofFIG.41.

A shown inFIG.43, the valve can be controlled by a crankshaft inside the valve chamber. The crankshaft passes into and out of the valve chamber through rotary seals (not shown).

As shown inFIG.44, an Actuator Valve is packaged such that two valves are inline and their controls come out the same side of the valve. This is a convenient configuration for controlling an actuator that is either hooked to the Reservoir (low pressure fluid supply) or the Supply (High pressure fluid supply). In this configuration, the reservoir valve rod near point C has a hole in the center of it. The Rod, which is connected to the supply valve rod near point B, passes through the hole. A Rod seal inside the reservoir valve is positioned near point D. The reservoir valve also passes through a seal near point C. The result is the valves are in line with each other. The Supply valve is controlled by moving the Rod and the Reservoir valve is controlled by moving the Rod near point D.

In order to reduce tolerance stack-up issues that may come in manufacturing and assembling the valve. It should be appreciated that these features are possible, without detriment to the system, due to the self-energizing seals of the valve. Depending on the size of the valves, tolerance stack-up between the Control mechanism down to the Head maybe tight. For example, the Seal may only be a 0.03 inch thick silicone membrane with a hole in the center. To make sure the Head is touching the membrane, the connector is set from the Control to the Head at a length such that its minimum length such that the Head is touching the Seal. Thus the tolerance stack up is taken up by compressing the Seal. If the connector consists of three parts in series cut to a tolerance of ±0.0025 inches, then the Head could be compressed into the membrane 0.015 inches, which is an unacceptable 50% compression. To have less critical tolerances, so manufacturing is less expensive, the self-energizing properties of the Seal allows for a compliant member under the Seal.FIG.45shows a valve with a 0.06-inch cross section diameter O-ring (Compliant Addition) under the Seal. With this extra O-ring, the compression is still 0.015 inch compression, but the item being compressed is now (0.03 inch thick seal+0.06-inch O-ring). This is only a 16% compression. It should be appreciated that the O-ring could be any device that increases the compliance of the seal. It could be a thicker seal, spring, or other compliant device known in the art. The addition of the compliant member does not adversely affect the system. In Mode1a, the seal flexes up and the compliance O-ring does not have an effect. In Mode1b, the seal flexes down and the compliant membrane actually allows the valve to open more, which is good. In Mode2a, the seal flexes up and the compliant O-ring does not have an effect. In Mode2b, the seal flexes down and the Head is free to move down into the Seal. Thus, the head passively travels down a bit farther, but the seal is still maintained. In Mode3, the valve is open, and the O-ring does not have an effect. In Mode4a, the Head is free to move downward and thus it maintains its seal with the Seal. In Mode4b, the Head is moved up and away from the Seal. The valve is open and the O-ring does not have an effect.

As shown inFIG.46, in order to assemble the valve, an insert piece is pressed into the outer Case. Ideally, the piece would be touching the Seal without compressing it. The reason is that if the Seal is made of a compliant material such as Silicone Rubber, then the compression will deform the Seal, which may have adverse effects. Assuming that the press fit of the piece creates a seal between the outer case and the insert piece. The Seal is not only capable of sealing against the Head but can seal against the pressed in piece and the Case. Thus, a small Gap can be left between the piece and the Seal. If P(A)>P(B) then the Seal lifts up and presses against the piece as in the left diagram ofFIG.12. If P(B)>P(A) then the seal drops down and presses against the Case.

Accordingly, the various valves and valve configuration set forth herein have applicability in a number of systems, including but not limited to pumps, hydraulic systems, pneumatic systems, actuators and other fluid systems where the valves of the present invention may have applicability.

It is contemplated, and will be apparent to those skilled in the art from the foregoing specification, drawings, and examples that modifications and/or changes may be made in the embodiments of the invention. It is expressly intended that the foregoing are only illustrative of various embodiments and modes of operation, not limiting thereto, and that the true spirit and scope of the present invention be determined by reference to the appended claims.

While the present invention has been described with reference to certain illustrative embodiments to illustrate what is believed to be the best mode of the invention, it is contemplated that upon review of the present invention, those of skill in the art will appreciate that various modifications and combinations may be made to the present embodiments without departing from the spirit and scope of the invention as recited in the claims. The claims provided herein are intended to cover such modifications and combinations and all equivalents thereof. Reference herein to specific details of the illustrated embodiments is by way of example and not by way of limitation.

Thus, aspects and applications of the invention presented here are described in the drawings and in the foregoing detailed description of the invention. Those of ordinary skill in the art will realize that the description of the present invention is illustrative only and not in any way limiting. Other embodiments of the invention will readily suggest themselves to such skilled persons including, without limitation, combinations of elements of the various embodiments. Various representative implementations of the present invention may be applied to any valve.

Unless specifically noted, it is intended that the words and phrases in the specification and the claims be given their plain, ordinary, and accustomed meaning to those of ordinary skill in the applicable arts. It is noted that the inventor can be his own lexicographer. The inventor expressly elects, as his own lexicographer, to use the plain and ordinary meaning of terms in the specification and claims unless they clearly state otherwise in which case, the inventor will set forth the “special” definition of that term and explain how it differs from the plain and ordinary meaning. Absent such statements of the application of a “special” definition, it is the inventor's intent and desire that the simple, plain and ordinary meaning to the terms be applied to the interpretation of the specification and claims.

The inventor is also aware of the normal precepts of English grammar. Thus, if a noun, term, or phrase is intended to be further characterized, specified, or narrowed in some way, then such noun, term, or phrase will expressly include additional adjectives, descriptive terms, or other modifiers in accordance with the normal precepts of English grammar. Absent the use of such adjectives, descriptive terms, or modifiers, it is the intent that such nouns, terms, or phrases be given their plain, and ordinary English meaning to those skilled in the applicable arts as set forth above.

Further, the inventor is fully informed of the standards and application of the special provisions of 35 U.S.C. § 112(f). Thus, the use of the words “function,” “means” or “step” in the Detailed Description of the Invention or claims is not intended to somehow indicate a desire to invoke the special provisions of 35 U.S.C. § 112(f) to define the invention. To the contrary, if the provisions of 35 U.S.C. § 112(f) are sought to be invoked to define the inventions, the claims will specifically and expressly state the exact phrases “means for” or “step for” and the specific function (e.g., “means for heating”), without also reciting in such phrases any structure, material or act in support of the function. Thus, even when the claims recite a “means for . . . ” or “step for . . . ” if the claims also recite any structure, material or acts in support of that means or step, or that perform the recited function, then it is the clear intention of the inventor not to invoke the provisions of 35 U.S.C. § 112(f). Moreover, even if the provisions of 35 U.S.C. § 112(f) are invoked to define the claimed inventions, it is intended that the inventions not be limited only to the specific structure, material or acts that are described in the illustrated embodiments, but in addition, include any and all structures, materials or acts that perform the claimed function as described in alternative embodiments or forms of the invention, or that are well known present or later-developed, equivalent structures, material or acts for performing the claimed function.