Abstract:
A valve assembly having a cap defining a first and second fluid flow passage for allowing the flow of fluid is attached to a seat member which is coupled to an actuator. A plunger having an adjustably attached diaphragm is maintained within the seat member and the actuator, and the plunger positions the diaphragm over the first and second fluid flow passage. The actuator controls the plunger and determines the retraction of the plunger to allow fluid flow and the insertion of the plunger to prevent fluid flow.

Description:
FIELD OF THE INVENTION 
     This invention relates to valves for controlling the flow of fluids, and especially to a solenoid valve utilizing a self adjusting fluid control means to ensure accurate and precise fluid flow and where the fluid flow control means may easily be replaced without having to disassemble the entire valve. 
     BACKGROUND OF THE INVENTION 
     There is a widespread demand for relatively small valves that can operate reliably, quickly, efficiently, and are capable of lasting for many millions of cycles. While there are applications for such valves in many fields, there are special requirements in chemical and biotechnology laboratories, ink jet printers, flux dispensing in manufacturing computer chips, and any other industries where accurate and precise fluid flow is necessary. In these applications, valves are opened frequently to allow the passage of various fluids therethrough in an exact and controlled fashion. 
     Bidirectional valves are known in the art where control of fluid flow is obtained independent of the direction of the flow of the fluid media. Such valves generally function by providing a flexible diaphragm which is directly attached to a plunger or other means such that the diaphragm is biased toward a valve seat closing the flow passage and thereby impeding fluid flow. The diaphragm is attached to the plunger in a rigid manner by using a threaded element or it is imbedded into the plunger. Such rigid attachment subjects the diaphragm to repeated opposing forces both at the point of attachment and at any radial compression point and may cause weakness in the diaphragm and failure thereof. In addition, some instruments use a plurality of the valves and it may be expensive and disruptive to find and replace individual valves whose diaphragm has failed. 
     Alternatively, U.S. Pat. No. 4,944,487 to Holterman discloses a diaphragm valve wherein the plunger is not attached to the diaphragm. The plunger biases the diaphragm against the valve seat and the diaphragm is maintained in place by radial compression along the perimeter of the diaphragm. Accordingly, Holterman&#39;s valve operates passively in response to pressure from the flow medium when the plunger is retracted. The passive operation of the diaphragm may fail if the pressure of the fluid is insufficient to deform the diaphragm in order to allow the flow thereof. In addition, the chemicals contained within certain fluids may crystallize and attach the diaphragm to the valve seat. Furthermore, the radial compression exerted on the diaphragm may cause the failure thereof by puncturing same by the exertion of such pressure. 
     The prior art does not address the need for accurate control of the volume of fluid dispensed over many millions of cycles of use where the diaphragm is adapted to adjust upon each opening and closure thereby reducing the stress placed thereon. Therefore, there remains a long standing and continuing need for an advance in the art of valve assemblies that is simpler in both design and use, is more economical, sturdy, and efficient in its construction and use, and can quickly be installed and removed from instrumentation having a plurality thereof. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is general object of the present invention to overcome the disadvantages of the prior art. 
     In particular, it is an object of the present invention to provide a valve apparatus that can operate with longevity. 
     It is another object of the present invention to provide a valve assembly that is economical to produce. 
     It is yet another object of the present invention to provide a valve assembly that is easily maintained but is sufficiently economical to replace. 
     It is another object of the present invention to provide a valve assembly that has a crisper opening and closing. 
     It is another object of the present invention to provide a valve assembly that provides easy adjustment of the rate of fluid flow therethrough. 
     It is another object of the present invention to provide a valve assembly that allows operation of the diaphragm in vacuum. 
     It is still another object of the present invention to provide a valve assembly that provides quick and exquisitely small valve movements with remarkable repetition relative to the volume of fluids passing therethrough. 
     It is another object of the present invention to provide a valve assembly that allows the adjustment of the diaphragm upon each opening and closing in order to achieve better fluid flow control. 
     It is yet another object of the present invention to provide a valve assembly that reduces the risk of leakage. 
     In keeping with the principles of the present invention, a unique self-adjusting diaphragm solenoid valve assembly is presented which overcomes the shortfall of the prior art. It is to be understood that the adjustable nature of the diaphragm may be incorporated into any valve assembly that is known in the art and is not limited to the solenoid valve assembly described herein. 
     The valve assembly has a cap that has an inner surface and an outer surface and a first and second aperture that extend from the inner surface and through the outer surface. On the outer surface, protrusions may be provided to connect the apertures to conduits for directing the flow of fluid to the apertures. On the inner surface, the apertures are symmetrically positioned and define a wall therebetween. A diaphragm that is preferably elastomeric is of sufficient size to simultaneously occlude the first and second apertures. 
     The cap is removably attached to a seat portion such that the diaphragm is maintained therebetween. The seat portion has a depression which is adapted to accommodate the diaphragm therein. The seat portion is further connected to the actuation region which is preferably a solenoid actuation means. A void extends axially through both said actuation region and the seat portion. A plunger means is received within said void and is adapted to connect with the diaphragm. 
     The diaphragm preferably has an elliptical shape and thus has a major and minor axis. Along the minor axis on a first side of the diaphragm there extends a first projection which is adapted to be received on the wall of the cap between the two apertures to seal between the same. On a second side of the diaphragm along is located the connecting means that connects the diaphragm to the plunger means in a pivoting manner. 
     The plunger means has an extension that connects a protuberance to the plunger means and the extension is smaller in diameter than the protuberance. The connecting means has a first prominence and a second prominence which extend parallel with the minor axis of the diaphragm and oppose one another to create an opening therebetween. A first lip and a second lip extend inwardly from first and second prominences and thereby narrow the size of the opening. 
     The opening is shaped to accommodate the protuberance therein in a tight fitting form and is further defined by the first and second lip. The first and second lip engage the protuberance and allow retraction of the diaphragm when the plunger is retracted. However, first and second lip allow enough opening therebetween to accommodate the extension and yet allow pivoting of the protuberance therein. 
     Thereby, when the plunger is retracted, the diaphragm is disengaged from the inner surface and wall of the cap and fluid is allowed to flow between the first and second aperture. When the plunger is reinserted, the diaphragm is biased against the inner surface and the wall and the pivoting attachment of the connecting means to the protuberance allow the diaphragm to adjust to achieve optimal occlusion of the first and second aperture to prevent fluid flow therebetween. 
    
    
     Such stated objects and advantages of the invention are only examples and should not be construed as limiting this invention. These and other objects, features, aspects, and advantages of the invention herein will become more apparent from the following detailed description of the embodiments of the invention when taken in conjunction with the accompanying drawings and the claims that follow. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     It is to be understood that the drawings are to be used for the purposes of illustration only and not as a definition of the limits of the invention. 
     In the drawings, wherein similar reference characters denote similar elements throughout the several views: 
     FIG. 1 is a perspective view of an unassembled valve apparatus. 
     FIG. 2 is an elevational view of an assembled valve apparatus. 
     FIG. 3 is a cross-sectional view of an assembled valve apparatus taken along line  3 — 3  of FIG.  2 . 
     FIG. 4 is an enlarged partial cross-sectional view of an assembled valve apparatus emphasizing the portion taken along line  4 — 4  of FIG.  3 . 
     FIG. 5 is rearward perspective view of the cap. 
     FIG. 6 is a frontal perspective view of the cap. 
     FIG. 7 is a frontal perspective view of the diaphragm. 
     FIG. 8 is a rearward perspective view of the diaphragm. 
     FIG. 9 is an elevation view illustrating the attachment of the diaphragm to the first member. 
     FIG. 10 is a frontal perspective view of an alternate preferred embodiment of the diaphragm. 
     FIG. 11 is an enlarged partial elevational view illustrating the connecting means receiving the protuberance. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIG. 1, therein is illustrated an exploded view of valve apparatus  10 . In addition, for a better understanding of the invention, an assembled elevational view is illustrated in FIG. 2, and an assembled cross-sectional view is illustrated in FIGS. 3 and 4, which should be viewed in conjunction with FIG. 1 in the following description. Valve apparatus  10  has a cap  12  that may be made of any rigid material, but is made of a plastic or resin material in general, and in a preferred embodiment, cap  12  is made of polyetheretherketone which is commonly referred to as “PEEK.” Cap  12  is preferably circular and has an inner surface  14  and an outer surface  16 . At least a first protrusion  18  and a second protrusion  20  extend from outer surface  16 . A first aperture  22  and a second aperture  24  are axially defined in first protrusion  18  and second protrusion  20  respectively. First protrusion  18  and second protrusion  20  are adapted to maintain respective conduits (not shown) thereon for delivery and flow of fluid therethrough. 
     Now also referring to FIGS. 5 and 6, first aperture  22  and second aperture  24  extend through inner surface  14  of cap  12 . In a preferred embodiment, inner surface  14  defines a first cavity  26  and a second cavity  28  therein. First cavity  26  and second cavity  28  are preferably symmetrically located in relation to one another and are in the shape of triangles in the plane of inner surface  14  wherein a base of each cavity  26  and  28  are substantially juxtaposed such that a wall  30  is created therebetween. Although cavity  26  and  28  are illustrated to have a triangular shape, it is to be understood that alternate shapes may also be utilized. 
     Cavities  26  and  28  are adapted to communicate with first aperture  22  and second aperture  24 . In a preferred embodiment, first and second apertures  22  and  24  are in communication with an apex of the triangular shape of cavity  26  and  28  respectively, wherein the apexes are located distal to the base of each cavity  26  and  28 . In addition, in a preferred embodiment, the depth of first cavity  26  and second cavity  28  is greater at the apex in comparison to each corresponding base thereof. At least a first opening  32  and a second opening  34  are located on cap  12  and are preferably substantially symmetrically located on outer surface  16  and axially extend through inner surface  14 . First opening  32  and second opening  34  are adapted to each receive an attaching means  36  such as, but not limited to, a threaded element or a pin member. It is also to be understood that the attaching means may be any appropriate adhesive means known in the art whereby the first and second openings  32  and  34  would be unnecessary for attachment and may be omitted. 
     Now also referring to FIGS. 7,  8 , and  9 , a diaphragm  38  is preferably comprised of an elastomeric material or any other appropriate material known in the art. Diaphragm  38  has a first side  40  and a second side  42 . The diameter of diaphragm  38  is of sufficient size to cover both first cavity  26  and second cavity  28  simultaneously. In a preferred embodiment, diaphragm  28  is substantially elliptically shaped such that the major axis is substantially aligned with the apexes of first cavity  26  and second cavity  28  and extends therebeyond. In addition, the minor axis of diaphragm  38  is adapted to axially align with wall  30  and is of sufficient size to enclose first cavity  26  and second cavity  28 . When first side  40  of diaphragm  38  is received on inner surface  14  of cap  12 , both cavities  26  and  28  are closed such that fluid therebetween is prevented. In a preferred embodiment, a first projection  44  extends along the minor axis of first side  40  of diaphragm  38 . First projection  44  is adapted to be removably received on wall  30  of cap  12  in a hermetically sealed fashion. 
     Now also referring to FIG. 10, therein is illustrated another preferred embodiment of diaphragm  38  wherein a second projection  46  is located on first side  40  of diaphragm  38 . Second projection  46  is a contiguous wall that is substantially equidistantly located from an outer edge  48  of diaphragm  38 . Second projection  46  is located at a sufficient distance such that both first cavity  26  and second cavity  28  are enclosed thereby at all times when valve  10  is assembled. 
     Now also referring to FIG. 11, a connecting means  50  is attached to second side  42  of diaphragm  38  in a generally centrally located position. Connecting means  50  is made of any substantially rigid material such as but not limited to metals and plastics. Connecting means  50  has a base  52  that attaches to second side  42  and has a first prominence  54  and a second prominence  56  extending from base  52 . First prominence  54  and second prominence  56  oppose one another and define an opening  58  therebetween, and opening  58  extends axially perpendicular to prominences  54  and  56 . First prominence  54  and second prominence  56  have a first lip  60  and a second lip  62  respectively that extend inwardly to narrow opening  58  therebetween. 
     A first member  64  has a generally elongated shape having a first end  66  and a second end  68 . First member  64  may be constructed of any substantially rigid material and is preferably metallic or any material that responds to magnetic forces in general, and more specifically, first member  64  is constructed of magnetic 430F stainless steel or similar magnetic alloy. First end  66  has an extension  70  thereon with a protuberance  72  extending therefrom. Protuberance  72  is larger than extension  70  in diameter and is adapted to be inserted into opening  58  of connecting means  50  whereby extension  70  is maintained between first lip  60  and second lip  62 . Upon retraction of first member  64 , protuberance  70  engages first lip  60  and second lip  62  and thus retracts diaphragm  38  therewith. Opening  58  is of sufficient size to allow rotational movement of protuberance  70  therein but maintains a proximal distance between protuberance  70  and first lip  60  and second lip  62  so that immediate retraction response can be obtained. 
     A first component  74  has a seat portion  76  and an actuation portion  78  communicating therewith. Seat portion  76  has a primary side  80  and a secondary side  82  that is connected to actuation portion  78 . Primary side  80  has a depression  84  that is generally elliptical in shape and is of sufficient size to receive second side  42  of diaphragm  38  therein in a generally form fitting fashion. In addition, depression  84  is of sufficient depth such that when second side  42  of diaphragm  38  is received therein, first side  40  of diaphragm  38  and primary side  80  of seat portion  80  are on an even plane. A first void  86  is substantially centrally located within depression  84  and extends axially through and out of secondary side  82  of seat portion  76  and is defined by an inner wall  88 . First void  86  is of sufficient size to accommodate connecting means  50  of diaphragm  38  therein but also to prevent diaphragm  38  from passing therethrough. A boundary  90  extends from depression  84  and is less than primary side  80  in height and is located radially outward to void  86 . Boundary  90  is of sufficient size to enclose first cavity  26  and second cavity  28  of cap  12  in order to maintain hermetic contact of diaphragm  38  to inner surface  14 . 
     A primary opening  92  and a secondary opening  94  may be provided on primary side  80  of seat portion  76  such that they are axially aligned with first opening  32  and second opening  34  respectively of cap  12 . After diaphragm  38  is attached to first member  64 , a first attaching means  36  may be inserted into first opening  32  and primary opening  92  and a second attaching means  36  may be inserted into second opening  34  and secondary opening  94  to join cap  12  to seat portion  76  in a removable fashion. 
     First void  86  also extends through actuation portion  78  and is adapted to receive first member  64  therein in a sliding fashion. First member is inserted into first void  86  from the actuation portion  78  such that protuberance  72  extends out of primary side  80  of seat portion  76  and receives connecting means  50  thereon. Cap  12  is in turn attached to primary side  80  of seat portion  76  to maintain diaphragm  38  within depression  84 . 
     In a preferred embodiment, a bore  96  is created between seat portion  76  and actuation portion  78  that is perpendicular to void  86 . A first element  98  is adapted to be received within bore  96  and has a first hollow  100  therein that is axially aligned with void  86 . First element  98  is inserted into bore  96  and first member  64  is inserted into void  86  as previously described and also passes through first hollow  100 . First element  98  is preferably disk shaped and is metallic or any material that responds to magnetic forces in general, and more specifically, first element  98  is constructed of magnetic 430F stainless steel or similar magnetic alloy. 
     A second member  102  having a primary end  106  and a secondary end  108  is received within first void  86  after first member  64  has been inserted such that a space  104  is maintained between second end  68  of first member  64  and primary end  106  of second member  102 . Secondary member  102  has a control element  110  thereon that engages inner wall  88  of actuation portion and determines the amount of space  104  between first member  64  and second member  102 . For purposes of illustration but not limitation, control element  110  is preferably a threaded means on second member  102  to control the depth of insertion thereof into first void  86 . Second member  102  may be constructed of any substantially rigid material and is preferably metallic or any material that responds to magnetic forces in general, and more specifically, Second member  102  is constructed of magnetic  430 F stainless steel or similar magnetic alloy. 
     A hole  112  is substantially axially defined within second member  102  and extends from primary end  106  and out of secondary end  108 . Hole  112  is adapted to receive a resilient means  114  therein such that resilient means  114  biases against second end  68  of first member  64 . For purposes of illustration but not limitation, resilient means  114  is a stainless steel coil or spring. A third member  116  having a front end  118 , a back end  120 , and a control member  122  thereon has a generally elongated shape and is then inserted into hole  112 . Third member  116  may be constructed of any substantially rigid material and is preferably metallic or any material that responds to magnetic forces in general, and more specifically, third member  116  is constructed of magnetic 430F stainless steel or similar magnetic alloy. Front end  118  is in contact with resilient means  114  such that resilient means  114  is maintained between front end  118  and second end  68  of first member  64 . 
     In a deactivated state, resilient means  114  forces first member  64  towards cap  12  such that diaphragm  38  prevents fluid flow between first aperture  22  and second aperture  24 . The force with which first member  64  is forced towards cap  12  is determined by control member  122 . If a greater force is needed, control member  122  is adjusted to shorten the distance between front end  118  of third member  116  and second end  68  of first member  64 . Conversely, the force of resilient means  114  may also be reduced by increasing the distance between front end  118  of third member  116  and second end  68  of first member  64 . 
     Actuation portion  78  has an actuator means  124  that is exemplary of a wide variety of actuators which can be used to move first member  64  axially and disengage diaphragm  38  from wall  30  and to open fluid flow between first cavity  26  and second cavity  28 . For example, actuator means such as, but not limited to, pneumatic actuators, hydraulic actuators, manual actuators, and electrical solenoid actuators may be used. In a preferred embodiment, an electrical solenoid actuator is used and is described herein; however, it is to be understood that the invention is not to be limited thereby. Actuator means  124  has a front portion  126 , back portion  128 , and middle portion  130  in the shape of a bobbin whereby middle portion  130  interconnects front portion  126  and back portion  128 . A solenoid winding  132  is wound around middle portion  130  and extends between front portion  126  and back portion  128 . Solenoid winding  132  is preferably made of elongated copper but may be made of any material that can conduct an electrical current. 
     A prominent portion  134  extends from back portion  128  of actuator means  124  and has connected thereto a first pin  136  and a second pin  138 . First pin  136  and second pin  138  respectively connect to opposing ends of solenoid winding  132  and supply electricity thereto. First pin  136  and second pin  138  may be mounted onto a printed circuit board (PCB) which allows a plurality of valves  10  to be located in close proximity to each other without the need for electrical wiring and connectors. 
     A second element  140  having a second hollow  142  therethrough is adapted to be received on back portion  128  of actuation portion  78  such that second hollow  142  is axially aligned with first void  86 . Second hollow  142  is of sufficient size to accommodate second member  102  therein. 
     A housing  144  has a first section  146  and a second section  148  interconnected by a middle section  150 . Housing  144  axially defines a vacuous portion  152  therein. First section  146  attaches to secondary side  82  of seat portion  76  such that actuation portion  78  and all the components therein are maintained within vacuous portion  152 . First section  146  may be attached to secondary side  82  by a binding means generally, but specifically, UV cementing may be used. Housing  144  may be constructed of any substantially rigid material and is preferably metallic or any material that responds to magnetic forces in general, and more specifically, housing  144  is constructed of magnetic 430F stainless steel or similar magnetic alloy. 
     Fluid enters from first aperture  22  of first protrusion  18  and is maintained within a region defined by first side  40  and first cavity  26 . It is to be understood that although first aperture is described for fluid inflow, it may also be reversed such that first aperture  22  functions for outflow. When an electrical current is applied to first pin  136 , solenoid winding  132 , first element  98 , second member  102 , third member  116 , second element  140  and housing  144  form a magnetic flux. The magnetic flux attracts second end  68  of first member  64  towards primary end  106  of second member  102  and overcomes the force exerted by resilient means  114 . As a consequence, diaphragm  38  disengages from wall  30  such that fluid flows to second cavity  28  and out through second aperture  24  of second protrusion  20 . 
     When the adjustment is completed and the correct rate of fluid flow is attained, a sealing means  154  may be applied to second section  148  of housing  144  to maintain the proper rate of fluid flow. Very quick and exquisitely small valve movements can be attained with increased repetitiveness and accuracy of the volume of fluid passing therethrough. In addition, the rotational movement provided by connecting means  50  and protuberance  70  of first member  64  allows diaphragm  38  to return to its original position and can self adjust to achieve optimal contact with wall  30 . 
     If diaphragm  38  should need replacement, cap  12  can be removed from primary side  80  of seat portion  76 . Connecting means  50  can then easily be removed from protuberance  72  and a new diaphragm  38  mounted thereon in a similar fashion. Once again cap  12  may be connected to primary side  80  of seat portion  76  and valve apparatus  10  would function in the same manner as before replacement because control element  110  and control member  122  would not have been adjusted. Therefore, the disengagement distance between diaphragm  38  and wall  30  would not be affected and the rate of fluid flow would remain constant. 
     The materials used in constructing the valve can be selected to provide resistance to various reagents and solutions. Valve apparatus  10  may also be made of a clear material to allow for visual inspection thereof. Valve apparatus  10  may be used alone or in concert with a plurality of valve apparatuses  10 . Valve apparatus  10  may be used in a variety of machines and for a variety of purposes such as, but not limited to, ink dispensing in printers, flux dispensing for computer chips, and micro dispensing for the biotechnology and chemical industry. 
     While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment thereof. Many other variations are possible without departing from the essential spirit of this invention. Accordingly, the scope of the invention should be determined not by the embodiment illustrated, but by the appended claims and their legal equivalents.