Patent Document

RELATED APPLICATIONS  
       [0001]    This application is a continuation of U.S. patent application Ser. No. 09/931,385, filed Aug. 14, 2001, which is a continuation-in-part of U.S. patent application Ser. No. 09/350,955, filed Jul. 9, 1999, now U.S. Pat. No. 6,273,117. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates to fluid pressure regulators, and particularly to regulators well suited for controlling the output pressure of elastomeric balloon or mechanical pumps. More specifically, the present invention relates to a variable fluid pressure regulator which allows for convenient adjustment of fluid outlet pressure.  
         BACKGROUND OF THE INVENTION  
         [0003]    Pressure regulators that reduce or cut off inlet flow of a fluid when the outlet pressure starts to exceed a predetermined maximum and that open or increase flow when the outlet pressure has been sufficiently reduced are well known in the art. Such regulators generally include a coil spring that biases a valve member open, and a pressure-sensing element responsive to excess inlet pressure which closes the valve member. In this arrangement, increasing liquid pressure compresses the spring to force the valve member towards a valve seat. As the valve member approaches the valve seat, liquid flow through the regulator becomes more restricted. When the defined pressure level is reached, further flow restriction is stopped, or the valve member contacts the valve seat to cut off flow. When the output pressure drops below the defined pressure, the valve member moves away from the valve seat and flow increases. This cycle is rapidly repeated over and over to maintain the output pressure at the desired setting.  
           [0004]    Numerous pressure regulating devices teach the use of a coil spring, such as U.S. Pat. No. 3,412,650 by Stang, U.S. Pat. No. 3,547,427 by Kelly, U.S. Pat. No. 3,603,214 by Murrell, U.S. Pat. No. 3,747,629 by Bauman, U.S. Pat. No. 3,825,029 by Genbauffe, U.S. Pat. 4,074,694 by Lee, U.S. Pat. No. 4,621,658 by Buezis et al., U.S. Pat. No. 4,744,387 by Otteman, U.S. Pat. No. 5,141,022 by Black, and U.S. Pat. No. 5,732,736 by Ollivier. However, a need exists for a pressure regulator device without a spring coil, thereby resulting in a more reliable device with fewer parts which is easier to assemble and costs less.  
           [0005]    The majority of the subject pressure regulators of the above-referenced patents are manufactured to provide a single, specific fluid outlet pressure or be adjustable between a high and a low setting. However, there also exists a need for a variable pressure regulator device that allows for the selection, from a range of values, of a desired fluid outlet pressure by a user. This capability is particularly desirable in connection with small pumps used in the medical field wherein fluids are being dispensed to a patient.  
         SUMMARY OF THE INVENTION  
         [0006]    A goal of preferred embodiments is to provide a simplified pressure regulator having fewer parts thereby making it easier to assemble, less expensive and less likely to break. Instead of having the traditional springs located above and below a flexible diaphragm, a resilient diaphragm is employed that by itself controls input flow and regulates output pressure. The diaphragm is made of an elasticomeric material, and is designed not only to act as a diaphragm, but also to replace the pressure sensing spring and the valve seat spring.  
           [0007]    Preferably, the diaphragm is manufactured to be flat, however, after installation into the regulator, an adjuster is moved to deflect the diaphragm. The amount of deflection corresponds with the desired outlet fluid pressure. The diaphragm resists deflection when outlet pressure is less than the desired level, but flexes towards a closed position when the outlet pressure exceeds this level. Thus, this diaphragm uniquely has the additional advantage of functioning as a spring without having any of the disadvantages.  
           [0008]    Additionally, a preferred embodiment of the fluid pressure regulator includes a cover, which engages the adjuster such that rotation of the cover results in rotation of the adjuster to deflect the diaphragm and adjust the fluid outlet pressure, as described above. Such a construction advantageously allows convenient adjustment of the fluid outlet pressure by medical personnel and, thus, permits the variable fluid regulator to accommodate a variety of fluid dispensing needs. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    These and other features of the present invention will be better understood by reference to the following detailed description when considered in conjunction with the accompanying drawing wherein:  
         [0010]    [0010]FIG. 1 is a cross-sectional view of a preferred embodiment of a pressure regulator;  
         [0011]    [0011]FIG. 2 is a cross-sectional view of an additional embodiment of a pressure regulator;  
         [0012]    [0012]FIG. 3 is an exploded, perspective view of the pressure regulator of FIG. 2 as viewed from above;  
         [0013]    [0013]FIG. 4 is an exploded, perspective view of the pressure regulator of FIG. 2 as viewed from below;  
         [0014]    [0014]FIG. 5 is a cross-sectional view of another embodiment of a pressure regulator;  
         [0015]    [0015]FIG. 6 is an exploded, perspective view of the pressure regulator of FIG. 5 as viewed from above;  
         [0016]    [0016]FIG. 7 is an exploded, perspective view of the pressure regulator of FIG. 5 as viewed from below. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]    Referring to the drawings, the pre-set pressure regulator, indicated generally by the numeral  10 , comprises a base  15 , a resilient wall or diaphragm  20 , a retainer  25 , and an initial adjuster in the form of a cap  30 . The base  15  has an inlet  35  where fluid is introduced into the regulator  10  and an outlet  40  where the fluid exits at the desired pressure. A central, axial passage  45  extends through the base  15 , and is in fluid communication with the inlet  35 . The diameter of the open end at the top of the passage  45  which is smaller than the lower portion forms a valve seat  50 . A plug  55  closes the lower end of the passage.  
         [0018]    The top surface of the base  15  is concave and forms the lower boundary of a fluid pressure-sensing chamber  60 . The perimeter of the top surface of the base member has an angled, annular shoulder  65  which defines a seating and gripping surface for the diaphragm  20 . The shoulder  65  has an externally threaded lip  70  which mates with interior threads on the retainer  25 , which is generally ring shaped. The outlet conduit  40  in fluid communication with the chamber  60  extends from the top surface of the base  15  to an exterior surface of the base  15 .  
         [0019]    The diaphragm  20  is a generally circular, preferably generally flat member which has an outer annular portion clamped between the base shoulder  65  and a flat annular surface  90  on the retainer  25  to seal that area. This causes the bottom surface of the diaphragm to form the upper boundary of the pressure-sensing chamber  60 . The diaphragm is preferably made of an elastomeric material, such as silicone so that it will be responsive to fluid pressure changes in the chamber  60  and has a significant “memory” so that it is self-restoring. Depending from the diaphragm  20  is an integral valve stem  75  which extends axially through the chamber  60  and into the passage  45 . A valve element  80  on the lower end of the valve stem is positioned in the passage  45  to cooperate with the valve seat  50 . The valve element is preferably ball-shaped as illustrated, but may be in the form of a disk or other suitable shape that will properly mate with the valve seat. During assembly, the valve element  80  may be lubricated with alcohol to enable it to be pushed through the valve seat into the passage  45 .  
         [0020]    The retainer  25  may be ultrasonically welded to the base  15  if desired. An annular area  95  of the retainer  25  slopes upwardly, and inwardly to an interiorly threaded collar  105 , which is part of the retainer. The adjuster cap  30  has a flat upper wall  110  and a cylindrical flange  115  extending downward into the collar  105 . The exterior surface of the flange  115  is threaded to mate with the threads of the collar  105 . The cap  30  is adjusted so that its lower annular end contacts the top surface of the diaphragm  20 . The circular, central section of the diaphragm, which is bounded by the cylindrical flange  120 , is responsive to fluid pressure in the chamber  60 . The loading by the adjusting cap  30  pushes the diaphragm  20  downward, thereby unseating the valve element  80 , as shown in the drawing. The adjuster may also be in sliding or cam-like engagement with the retainer.  
         [0021]    The upper surface of the diaphragm  20  and the initial adjusting cap  30  form an upper interior space  130  that is separated from the pressure-sensing chamber  60  by the diaphragm  20 . Vents  125  extend through the flat surface  110  of the adjusting cap  30  to prevent pressure build-up in the upper interior space  130 , and to facilitate turning the adjuster cap  30  when setting the desired pressure.  
         [0022]    The base  15 , plug  55 , adjusting cap  30 , and retainer  25  are preferably made of polyvinyl chloride, but may be made of other durable, inexpensive materials known to those of ordinary skill in the art.  
         [0023]    When the diaphragm  20  is assembled within the pressure regulator  10 , between the angled shoulder  65  of the base  15  and the flat surface  90  of the retainer  25 , the valve member  80  is seated in a sealed closed position. After a pressure source is attached to the inlet  35 , the cap  30  is advanced against the diaphragm causing the annular tip of the cap flange  115  to deflect the diaphragm  20 , thereby unseating the valve element  80  from the valve seat  50 . While the valve element  80  is unseated, fluid travels through the inlet  35  and the valve seat  50 , flows into the fluid sensing chamber  60 , and out through outlet  40 . The cap is adjusted until the desired outlet pressure is attained. For a preset pressure device, a suitable adhesive or the like is applied to the threads at  115  to prevent changes in the output pressure setting.  
         [0024]    When the pressure of the fluid in the chamber  60  exerts a force against the bottom of the diaphragm  20  greater than the desired value initially set by the adjusting cap  30 , a force imbalance occurs. The force of the fluid in the chamber  60  pushes the resilient central section of the diaphragm  20  upward causing the valve member  80  to move in a flow-reducing or flow stopping direction towards the valve seat  50 . When the outlet pressure drops below the desired level, the resilient diaphragm central section moves the valve member  80  away from the valve seat  50  and fluid flow into the chamber  60  increases. The resiliency of diaphragm  20  provides its central section the self-restoring flexibility to respond to the pressure of the fluid in the fluid pressure-sensing chamber  60 . Consequently, diaphragm  20  is an active member responsive to pressure changes without the need for a conventional spring.  
         [0025]    The valve stem and the valve may be made of the same material as the diaphragm  20  and the valve member  80 , and may be made as a one piece unit. However, a valve stem  75  made from a material stiffer than that used to make the diaphragm  20  is better able to maintain a constant pressure over a wider range of input pressures. To increase stiffness and obtain this improved effect, a rigid pin (not shown) may be inserted into the valve stem  75 , after the diaphragm  20  is assembled into the valve body but before the adjusting cap  30  is installed. Alternatively, the cross section of the valve stem  75  may be increased over part or all of its length to increase stiffness. Further, the valve stem may be a completely separate part that links a separate valve element to the diaphragm.  
         [0026]    The pressure regulator is useful in many applications but is particularly suited to control the output pressure of elastomeric balloon or other mechanical pumps.  
         [0027]    FIGS.  2 - 4  illustrate an additional embodiment of a fluid pressure regulator, indicated generally by the reference numeral  10 ′. The pressure regulator  10 ′ is similar in construction and function to the pressure regulator  10  of FIG. 1. Accordingly, like reference numerals will be used to denote like components, except that a (′) will be added.  
         [0028]    With similarity to the embodiment of FIG. 1, pressure regulator  10 ′ comprises a valve body including a base  15 ′ and a retainer  25 ′, a resilient wall or diaphragm  20 ′, and an adjuster in the form of a cap  30 ′. The base  15 ′ has an inlet  35 ′ where fluid is introduced into the regulator  10 ′ and an outlet  40 ′ where the fluid exits at the desired pressure. A central, axial passage  45 ′ extends through the base  15 ′, and is in fluid communication with the inlet  35 ′. The diameter of the open end at the top of the passage  45 ′, which is smaller than the lower portion, forms a valve  50 ′. A plug  55 ′ closes the lower end of the passage.  
         [0029]    As with the embodiment of FIG. 1, the diaphragm  20 ′ of the present pressure regulator  10 ′ is clamped between the base  15 ′ and the retainer  25 ′. Therefore, the bottom surface of the diaphragm  20 ′ forms the upper boundary of the pressure sensing chamber  60 ′. An upper surface of the base  15 ′ forms the lower boundary of the pressure sensing chamber  60 ′. Depending from the diaphragm  20 ′ is an integral valve stem  75 ′, which extends axially through the chamber  60 ′ and into the passage  45 ′. A valve element  80 ′ on the lower end of the valve stem is positioned in the passage  45 ′ to cooperate with the valve seat  50 ′.  
         [0030]    As in the embodiment of FIG. 1, the adjuster cap  30 ′ of the present pressure regulator  10 ′ is threadably engaged within a central portion of the retainer  25 ′. The adjuster  30 ′ may be advanced or retracted relative to the retainer  25 ′ such that a lower annular end  120 ′ contacts the top surface of the diaphragm  20 ′. Advancing or retracting the adjuster  30 ′ alters the force necessary to close the valve element  80 ′ against the valve seat  50 ′, thereby adjusting the fluid outlet pressure of the pressure regulator  10 ′, as described above with respect to the embodiment of FIG. 1.  
         [0031]    The pressure regulator  10 ′ of FIGS.  2 - 4  additionally comprises a cover  150 . Preferably, the cover  150  is rotatably supported on the retainer  25 ′ and engages the adjuster  30 ′ such that the adjuster  30 ′ is fixed for rotation therewith. Thus, rotation of the cover  150  results in corresponding rotation of the adjuster  30 ′ such that the deflection of the diaphragm  20 ′ is altered, thereby adjusting the fluid outlet pressure.  
         [0032]    With reference to FIGS. 3 and 4, the cover  150  preferably includes a plurality of flexible lock tabs  152 . The lock tabs  152  engage the retainer  25 ′ to hold the cover  150  in a substantially fixed axial relationship with the retainer  25 ′, while allowing rotation with respect thereto.  
         [0033]    Each lock tab  152  includes a substantially transversely extending lock surface  154  configured to engage a retaining surface  156  of the retainer  25 ′. The retaining surface  156  may be a transversely extending uninterrupted annular surface. However, the retaining surface  156  may also include a series of interrupted surfaces, preferably with the interruptions being less than a width of any one of the flexible lock tabs  152 .  
         [0034]    The illustrated pressure regulator  10 ′ includes four, equally spaced lock tabs  152  (FIG. 4), however, a lesser or greater number of lock tabs  156  may be used. Advantageously, the lock tabs  152  and retaining surface  156  construction allow assembly of the cover  150  to the retainer  25 ′ without the use of tools or additional fasteners. However, other suitable coupling methods may also be used.  
         [0035]    With reference to FIG. 2, the cover  150  includes a pair of downwardly extending shafts or pins  157  which engage vent holes  125 ′ of the adjuster cap  30 ′. The shafts  157  may be of a smaller diameter than that of the vent holes  125 ′ such that pressure build-up in the upper chamber  130 ′ is avoided.  
         [0036]    The pair of shafts  157  fix the adjuster cap  30 ′ for rotation with the cover  150 , while simultaneously allowing the adjuster cap  30 ′ to move axially with respect to the cover  150  by sliding on the shafts  157 . Thus, when the cover  150  is rotated, the adjuster cap  30 ′ both rotates, due to its engagement with the cover  150  via the shafts  157 , and moves axially with respect to the cover  150 , due to its threaded engagement with the retainer  25 ′.  
         [0037]    The pressure regulator  10 ′ also includes a catch, or detent, mechanism  158  arrangement for locating the cover  150  in a desired angular position with respect to the retainer  25 ′. Each of a plurality of recesses  160  define a plurality of angular positions relative to the base  15 ′. The cover  150  includes a depending flexible tab  162  adjacent the cover periphery. The tab  162  includes an inwardly extending projection  164  (FIG. 4). The illustrated projection  164  is hemispherical in shape and each of the recesses  160  are substantially semi-cylindrical in shape. However, other suitable mating shapes may also be used, as can be determined by one of skill in the art.  
         [0038]    With reference to FIG. 2, the catch mechanism  158  is constructed such that the projection  164  is biased into engagement with a recess  160  by the inherent biasing force of the flexible tab  162 . As a result, the cover  150  and thus the adjuster cap  30 ′ are held in one of the annular positions defined by the plurality of recesses  160 . When the cover  150  is rotated relative to the base  15 ′ with a sufficient force, the projection  164  is disengaged from its current recess  160  and moves into engagement with the next adjacent recess  160  in the direction of rotation of the cap  150 . Preferably, the inherent biasing force of the flexible tab  162  is such that a caregiver and/or patient may rotate the cover  150  by hand, while also inhibiting undesired rotation of the cover  150  due to vibrations or inadvertent contact.  
         [0039]    Advantageously, with such a construction, rotation of the cover  150  results in rotation of the adjuster cap  30 ′ which, in turn, alters the deflection of the flexible diaphragm member  20 ′. As discussed above, the outlet fluid pressure is influenced by the deflection of the flexible diaphragm member  20 ′. Accordingly, the pressure regulator  10 ′ allows a caregiver and/or patient to easily adjust the fluid outlet pressure to a desired value.  
         [0040]    With reference to FIG. 3, the fluid pressure regulator  10 ′ includes an indicator arrangement  166 , which correlates the angular position of the cover  150  with a resulting fluid outlet pressure. Advantageously, with such a construction the caregiver is able to adjust the variable pressure regulator  10 ′ to a proper outlet pressure for a specific fluid being dispensed.  
         [0041]    The illustrated indicator arrangement  166  comprises an annular scale  168  on the retainer  25 ′. A reference indicia  170  is provided on the cap  150  and, when the cap  150  is assembled to the retainer  25 ′, is aligned such that at least a portion of the scale  168  is indicated by the reference indicia  170 . In the illustrated embodiment, the reference indicia  170  comprises a window  172  and an arrow  174 . The window  172  is sized and shaped preferably to display one demarcation of the scale  168 . The arrow  174  allows for rapid identification of the location of the window  172 , and may or may not be provided.  
         [0042]    The scale  168  of the illustrated embodiment is an index scale, which provides a relative indication of outlet pressure. Thus, each range of the index scale  168  may correspond to a predetermined value, or a range of values, for the fluid outlet pressure. Alternatively, the scale  168  may provide actual fluid pressure outlet values.  
         [0043]    In an alternative arrangement, the scale  168  may be provided on the cap  150  and the reference indicia  170  may be located on the retainer  25 ′, or possibly the base  15 ′. In this arrangement, the reference indicia  170  may comprise a projection and/or colored region of the retainer  25 ′ or base  15 ′. Of course, other suitable arrangements for indicating a value on a scale may also be used. As such, it is not intended for the indicator arrangement  166  to be limited simply to the embodiments disclosed herein, but to include other suitable variations.  
         [0044]    FIGS.  5 - 7  illustrate an alternative arrangement of the catch mechanism  158 . In this embodiment, the recesses  160  are defined on an upper annular surface of the retainer  25 ′ and the flexible tab  162  is correspondingly located on an upper surface of the cover  150 . In addition, the recesses  160  are generally triangular in cross-section, as viewed in FIG. 5, with the radially innermost wall portion being rounded (FIG. 6). With reference to FIG. 7, the projection  164  is semi-cylindrical in shape. Otherwise, the embodiment of FIGS.  5 - 7  is similar in construction and function to the embodiment described immediately above.  
         [0045]    Although this invention has been described in terms of certain embodiments, other embodiments apparent to those of ordinary skill in the art are also within the scope of this invention. Thus, various changes and modifications may be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is intended to be defined only by the claims that follow.

Technology Category: 4