Abstract:
A seat cup seal for a valve includes a base portion and a nipple portion projecting outwardly from the base portion. The nipple portion and said base portion define a blind bore about a longitudinal axis that opens in the base portion. The nipple portion defines a transverse end wall at an outermost end relative to the base that is adapted for sealingly engaging an associated valve seat. A flexible shoulder portion interconnects the base portion and the nipple portion so that said nipple portion is selectively movable between a first, relaxed position where the transverse end wall is spaced a first distance from the base and a second, retracted position where the transverse end wall is spaced a second distance from the base, with the second distance being less than the first distance. A plurality of biasing ribs projects outwardly from and extending between the base portion and the nipple portion. The biasing ribs, which are conformed in one of several suitable arrangements, bias or urge the nipple portion toward the first position when it is in its second position. In this manner, the seat cup does not require a coil spring or other separate biasing agent to urge the transverse end wall into sealing engagement with the associated valve seat.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims priority from U.S. provisional application No. 60/182,359 filed Feb. 14, 2000. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    This invention relates to a novel valve in general and more specifically to a valve construction embodying a novel seal or sealing means. The particular valve assembly here involved and the novel seal which forms a part of the valve assembly are particularly well suited for use in the liquid food dispensing industry but are by no means restricted to such application.  
           [0003]    For ease of description, the seal will be referred to hereinafter as a “seat cup.” Seat cups, in general, are widely known and derive their name from the fact that they act against a valve seat and have an overall cup-like configuration. Seat cups are generally fabricated from silicone or a like elastomeric resilient material and include a cylindrical base portion and a co-axial nipple portion extending from the base portion and connected thereto by a shoulder. The nipple portion is reduced in cross-sectional dimension with respect to the base portion and is generally cylindrical or frusto-conical converging away from the base. This assembly forms an upwardly opening chamber or recess resembling a cup. The nipple portion terminates in a surface transverse to the longitudinal axis of the seat cup, thereby providing a free or distal end which, as will become apparent hereinafter, provides a portion which is adapted to cooperate sealingly with a valve seat.  
           [0004]    When a seat cup of this prior design is operatively placed in the seal chamber of a valve, the base portion is held against axial and lateral displacement relative to the valve body in a position aligned with, but removable from, the valve seat. The nipple portion extends from the base portion toward the valve seat and its free end engages the seat in a fluid-tight sealing relationship to control fluid flow through the valve. A suitable means is employed to mount the nipple removably to the inner end of a reciprocal valve stem which is also aligned with the valve seat. The valve stem projects outwardly from the seat cup recess and an opposite, free end of the stem is connected to an actuator. Upon use of the actuator to move the stem away from the seat, the nipple portion of the seat cup is also partially retracted relative to the seat. Due to flexure at the shoulder, the nipple portion telescopes within the base portion when retracted. Such retraction results in breaking the seal at the valve seat, thereby permitting fluid flow through the valve.  
           [0005]    Heretofore, the seat cup has been biased into sealing engagement with the seat through use of a separate spring. In prior devices, a coil spring is coaxially positioned about the stem and a first end of the spring is engaged with a flange on the inner end of the stem while a second end of the spring is engaged with a fixed portion of the valve. The spring ensures that the nipple portion of the seat cup is maintained in tight sealing relation with the valve seat. While this arrangement has proven to be effective, use of a spring adds considerable cost and some complexity to the valve. Therefore, in light of the foregoing, it has been deemed desirable to develop a “springless” seat cup which includes means integral therewith for positively biasing the seat cup into engagement with the valve seat after being retracted away from same, even after many cycles of use.  
         SUMMARY OF THE INVENTION  
         [0006]    In accordance with the present invention, a seat cup seal for a valve includes a base portion and a nipple portion projecting outwardly from the base portion. The nipple portion and said base portion define a blind bore about a longitudinal axis that opens in the base portion. The nipple portion defines a transverse end wall at an outermost end relative to the base that is adapted for sealingly engaging an associated valve seat. A flexible shoulder portion interconnects the base portion and the nipple portion so that said nipple portion is selectively movable between a first, relaxed position where the transverse end wall is spaced a first distance from the base and a second, retracted position where the transverse end wall is spaced a second distance from the base, with the second distance being less than the first distance. A plurality of biasing ribs projects outwardly from and extending between the base portion and the nipple portion. The biasing ribs, which are conformed in one of several suitable arrangements, bias or urge the nipple portion toward the first position when it is in its second position. In this manner, the seat cup does not require a coil spring or other separate biasing agent to urge the transverse end wall into sealing engagement with the associated valve seat.  
           [0007]    One advantage of the present invention is that it provides a new and improved seat cup for a valve which does not require use of a separate spring for biasing the seat cup into engagement with a sealing seat of the valve.  
           [0008]    Another advantage of the present invention resides in the provision of a springless seat cup which includes smoothly transitioned regions between interconnected portions and controlled wall thicknesses so that it resists breakage even after many thousands of cycles.  
           [0009]    A further advantage of the present invention is found in the provision of a springless seat cup for a valve which greatly simplifies assembly of the valve and reduces the cost of same.  
           [0010]    Still other benefits and advantages of the present invention will become apparent to those of ordinary skill in the art to which the invention pertains upon reading and understanding the following specification. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    The invention may take physical form in certain parts and arrangements of parts, preferred embodiments of which are described in detail herein and illustrated in the accompanying drawings which form a part hereof and wherein:  
         [0012]    [0012]FIG. 1 is a side view, partially in cross-section and partially in elevation, of a springless seat cup formed in accordance with the present invention as operatively positioned in an associated valve assembly to block the flow of liquid therethrough;  
         [0013]    [0013]FIG. 2 illustrates the valve assembly and seat cup of FIG. 1, with the seat cup shown in its open position to permit liquid flow through the valve assembly;  
         [0014]    [0014]FIG. 3 is a side elevational view of the springless seat cup illustrated in FIG. 1;  
         [0015]    [0015]FIG. 4 is a cross-sectional view taken along line  4 - 4  of FIG. 3;  
         [0016]    [0016]FIG. 5 is a bottom plan view of the seat cup illustrated in FIG. 3;  
         [0017]    [0017]FIG. 6 is a cross-sectional view taken along line  6 - 6  of FIG. 5;  
         [0018]    [0018]FIG. 7 is a side elevational view of an alternative springless seat cup formed in accordance with the present invention;  
         [0019]    [0019]FIG. 8 is a cross-sectional view taken along line  8 - 8  of FIG. 7;  
         [0020]    [0020]FIG. 9 is a bottom plan view of the seat cup shown in FIG. 7;  
         [0021]    [0021]FIG. 10 is a cross-sectional view taken along line  10 - 10  of FIG. 9;  
         [0022]    [0022]FIG. 11 is a side elevational view of still another alternative springless seat cup formed in accordance with the present invention;  
         [0023]    [0023]FIG. 12 is a bottom plan view of the springless seat cup shown in FIG. 11; and,  
         [0024]    [0024]FIG. 13 is a cross-sectional view taken along line  13 - 13  of FIG. 11. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0025]    Referring to FIG. 1, a valve assembly is illustrated and indicated generally at  10 . The valve assembly  10  comprises a body  11  having a fluid outlet  12  and a fluid inlet  13 . A fluid passageway  14  is provided in the valve body  11 , the former being in communication with the outlet and inlet  12 , 13 , respectively.  
         [0026]    The passageway  14  comprises a sealing seat  15  oriented transversely of the axis of the outlet  12 . The passageway  14  is otherwise defined by a frusto-conical region  16  which merges into an enlarged cylindrical actuator opening  18 . The portions  16 , 18  together define a seal-receiving chamber C. The actuator opening  18  is threaded on its outer periphery  19  to receive a correspondingly threaded cap assembly  20 .  
         [0027]    The cap assembly  20  comprises an actuator including a bonnet member  21  having a central opening  22  to receive a stem  23  which is slidable relative to the bonnet member. A handle  24  is pivotally attached to the stem  23  by a pin  25 . The handle  24  includes an arcuate cam portion  26  for purposes to be hereinafter described. The stem  23  includes an enlarged knob  27  on its lower extremity which is connected to the remainder of the stem  23  by a reduced-diameter cylindrical portion  28 . A radially enlarged flange  29  separates the knob  27  and reduced-diameter portion  28  from the remainder of the stem  23 .  
         [0028]    With reference now also to FIGS.  3 - 6 , received in the seal chamber C is a seat cup component  34  made from silicone or another suitable elastomeric or resilient material. The seat cup  34  comprises a generally tubular, cylindrical nipple portion  35  with a curved, transverse end wall  36  closing the distal end of the nipple  35 . The end wall  36 , when the seat cup is operatively received in the chamber C, is adapted to engage the sealing seat  15  in a fluid-type relationship. Of course, the nipple portion  35  may alternatively be conformed to have any other suitable overall shape, e.g., frusto-conical converging toward the end wall  36 .  
         [0029]    Provided in the end wall  36  of the nipple portion  35  is a blind bore  37  formed generally along the longitudinal axis of the seat cup  34  with the inner end of the bore  37  defined by an enlarged portion  38  which is similar in configuration to the knob  27  on the end of the stem  23 . The knob  27  is removably snap-fitted into the enlargement  38  and the reduced-diameter cylindrical stem portion  28  is received in the remainder of the bore  37 .  
         [0030]    The seat cup  34  further comprises a tubular or otherwise conformed base portion  40  which is coaxial with the nipple portion  35  and radially enlarged relative thereto. Again, the base portion  40  need not necessarily be tubular, and other shapes for same are contemplated within the scope of the present invention. The tubular base portion  40  has a wall thickness T 1 . An upper edge  42  of the tubular base portion  40  abuts an inner surface  44  of the bonnet member  21 , while the cylindrical outer surface  46  of the tubular base portion  40  lies adjacent the enlarged cylindrical portion  18  of the seat cup chamber C.  
         [0031]    The nipple portion  35  and the tubular base portion  40  are interconnected by a flexible transverse shoulder portion  50 . The shoulder portion  50  comprises a wall thickness T 2  which is reduced relative to the wall thickness T 1  of the tubular base portion  40 . The shoulder portion  50  also defines a fillet region  52  which smoothly blends the nipple portion  35  into the tubular base portion  40 . The wall thickness T 2  of the shoulder portion  50  also defines an inner curved shoulder surface  54  which generally corresponds to the fillet region  62 .  
         [0032]    The seat cup  34  further comprises a plurality of biasing ribs R which project radially outwardly therefrom and are preferably uniformly and circumferentially spaced about an outer surface of the nipple portion  35 . The ribs R extend axially between the end wall  36  and the tubular base portion  40 , preferably parallel to the axis of the bore  37 . It has been found most preferable to form the seat cup  34  with a total of at least seven such ribs R, e.g., the seat cup  34  includes eight, although less can be used without departing from the overall scope and intent of the present invention.  
         [0033]    Each rib R includes a first end  60  connected to the shoulder  50 , a top land surface  62 , and a second end  64  connected to the end wall  36 . The top land surface  62  at the first end  60  of each rib R curves outwardly, away from the nipple portion  35  and blends into the cylindrical surface  46  of the tubular base portion  40 . At this first end  62 , each rib has a height H 1  (FIG. 6) which, together with the thickness T 2  of the shoulder  50 , defines a substantial thickness T 3  which is greater than the thickness T 1  of the base portion  40  and, thus, more resistant to deformation. At the opposite, second end  64  of each rib R, the top land surface  62  curves inwardly toward the nipple portion  35  and blends smoothly into the end wall  36 . This, then, ensures that the end wall  36  comprises a smooth and uninterrupted portion for mating in a fluid-tight manner with the seat  15  of the valve body  11 . As is apparent in FIG. 1, it has been found most preferable that, when the seat cup  34  is operatively placed in the chamber C with the end wall  36  engaged with the seat  15 , the top land surfaces  62  of the ribs R lie adjacent the frusto-conical region  16  defining the chamber C to ensure proper alignment of the seat cup  34  in the chamber.  
         [0034]    With reference again to FIGS.  3 - 6 , the ribs R are separated from each other by circumferentially extending bottom land or valley regions  70  which are preferably arcuate and transition smoothly into the ribs R. The bottom land regions  70  between successive ribs R extend from a first end  72  which connects to and blends smoothly into the shoulder fillet region  52 . At an opposite axial end  74 , each bottom land region  70  connects with the end wall  36 , without interrupting a portion thereof which is adapted to mate with the valve seat  15 . Also, each rib R defines a uniform circumferential width or thickness along its axial length.  
         [0035]    Operation of the springless seat cup  34  will now be explained with particular reference to FIGS. 1 and 2. In an operative position, the seat cup  34  is received in the chamber C as described above. FIG. 1 illustrates the seat cup  34  in its first or normally closed position wherein the end wall  36  of the nipple portion  35  is sealingly engaged with the valve seat  15 . In this first position, the bonnet member  21  exerts a preloading force on the seat cup  34  toward the valve seat  15  as controlled by the threaded connection  19  between the bonnet  21  and the body  11 . The preloading force is transmitted to the end wall  36  primarily through the biasing ribs R. This preloading ensures a fluid-tight seal between the wall  36  of the seat cup  34  and valve seat  15  when the seat cup is in this first, normally closed position.  
         [0036]    With reference now also to FIG. 2, manual rotation of the handle  24  about the pin  25  (in either direction) causes the cam surface  26  thereof to bear against the bonnet member  21  and, consequently, results in the stem  23  being pulled away from the seat  15 . Due to the interconnection of the stem  23  and the seat cup  34  in the bore  37  and enlarged portion  38  thereof, the stem  23  exerts a pulling force on the nipple portion  25  of the seat cup  34  in a direction away from the seat  15 . The tubular base portion  40  of the seat cup  34  is restrained from movement away from the seat  15  due to the abutment between its upper edge  42  and the bonnet inner surface  44 . Also, the wall thickness T 1  of the tubular base portion  40  is sufficient so that it resists deformation. The closely surrounding cylindrical portion  18  of the valve body  11  also supports the tubular base portion  40  of the seat cup  34  and prevents lateral movement thereof.  
         [0037]    On the other hand, the relatively reduced wall thickness T 2  of the shoulder region  50  promotes flexure of the seat cup  34  in that region so that the nipple portion  35  retracts away from the seat  15  and telescopes partially into the tubular base portion  40  so that the end wall  36  is moved to a second position closer to the base portion  40 . Retraction of the nipple portion  35  relative to the tubular portion  40  in this manner also results in deformation of the ribs R at their first ends  60 . However, the thickness T 3  of the walls of the seat cup  34  at the first end  62  of each rib R provides a biasing force which resists this retraction of the nipple portion  35  relative to the valve seat  15 . Accordingly, upon a user of the valve  10  releasing the handle  24 , the ribs R bias the nipple portion  35  away from the tubular base portion  40  toward and into fluid-tight engagement with the valve seat  15  without aid of a coil spring or other like separate biasing device.  
         [0038]    FIGS.  7 - 10  illustrate an alternative springless seat cup  134  in accordance with the present invention. Except as shown in FIGS.  7 - 10  and/or as described herein, the seat cup  134  is otherwise the same as the seat cup  34 . Consequently, in FIGS.  7 - 10 , like portions of the seat cup  134  relative to the seat cup  34  are identified with like reference numerals which are 100 greater than the reference numerals used in FIGS.  1 - 6 . New portions of the seat cup  134  are identified with new reference numerals and letters.  
         [0039]    The nipple portion  135  of the seat cup  134  is joined to the tubular base portion  140  by way of a transverse shoulder  150 . Like the seat cup  34 , the shoulder  150  comprises an arcuate fillet region  152  which smoothly transitions and blends the nipple portion  135  into the shoulder  150 . The shoulder portion has a wall thickness T 4  which is greater than the thickness T 2  used in the seat cup  34 , but still less than the wall thickness T 1  of the tubular base portion  140  to promote flexure of the shoulder  150 .  
         [0040]    The seat cup  134  also comprises a plurality of biasing ribs R′ which are similar to the ribs R in that they extend continuously between and connect the shoulder  150  and the end wall  136 . However, as is evident from FIG. 8, the ribs R′ have a T-shaped cross-section owing to the fact that they have a smaller circumferential width adjacent the nipple portion  135  and a larger circumferential width at the top land surface  200  spaced radially from the nipple portion  135 , i.e., the top land surface  200  of each rib R′ is wider relative to a base portion  202  of each rib. At a first end  204  of each rib R′, the top land surface  200  intersects the shoulder  150  at an angle which is preferably approximately  900 . At an opposite, second end  208  of each of the biasing ribs R′, the top land surface  200  curves inwardly toward the nipple portion  135  and blends smoothly into the end wall  136  so as not to interrupt that portion of the wall  136  which is adapted to mate with the seat  15  of an associated valve body  11 .  
         [0041]    As is most readily apparent in FIGS. 8 and 9, the valleys or bottom land regions  210  interconnecting or defined between adjacent ribs R′ are provided by the nipple portion  135 , itself, i.e., the base portion  202  of each T-shaped rib R′ is connected to the nipple portion  135  and projects radially outward therefrom.  
         [0042]    The springless seat cup  134  functions in the same manner as the springless seat cup  34  in that the ribs R′ bias the end wall  136  into engagement with the seat  15  for purposes of blocking fluid flow from the inlet  13  to the outlet  12  of an associated valve body  11 . Furthermore, the reduced wall thickness T 4  in the shoulder region  150  relative to the wall thickness T 1  of the tubular base portion  140  promotes flexure in the shoulder region. Accordingly, the seat cup  134  is selectively movable away from the seat  15  by rotational movement of the handle  24  of an associated valve body  11 , but returns to its normally closed position in engagement with the seat  15 , upon the handle  24  being released due to the biasing force of the ribs R′.  
         [0043]    FIGS.  11 - 13  illustrate still another alternative springless seat cup  234  in accordance with the present invention. Except as shown in FIGS.  11 - 13  and/or as described herein, the seat cup  234  is otherwise the same as the seat cup  34 . Consequently, in FIGS.  11 - 13 , like portions of the seat cup  234  relative to the seat cup  34  are identified with like reference numerals which are 200 greater than the reference numerals used in FIGS.  1 - 6 . New portions of the seat cup  234  are identified with new reference numerals and letters.  
         [0044]    The nipple portion  235  of the seat cup  234  defines a circular cross-section with a cylindrical outer surface. The base portion  240  is preferably cylindrical or, as shown, slightly tapered toward the nipple portion  235 . The nipple portion  235  is joined to the base portion  240  by way of a transverse shoulder  250 . Like the seat cup  34 , the shoulder  250  comprises an arcuate region  252  which smoothly transitions and blends the nipple portion  235  into the shoulder  250 . The shoulder portion  250  has a wall thickness T 6  less than the wall thickness T 7  of the base portion  240  to promote flexure of the shoulder  250 .  
         [0045]    The seat cup  234  also comprises a plurality of biasing ribs R″ that extend between and connect the shoulder  250  and the nipple portion  235 . However, as is evident from FIGS. 11 and 12, the ribs R″ have a non-uniform cross-section along their axial length. Specifically, adjacent the shoulder  250 , the ribs R″ define a first portion R 1 ″ that has a larger circumferential width than a second rib portion R 2 ″ that is separated from the shoulder by the first portion R 1 ″. The first portion R 1 ″ tapers moving toward the end wall  236  and blends into the second rib portion R 2 ″. The second portion R 2 ″, itself, preferably defines a uniform width along its length. Each rib R″ terminates approximately halfway between the shoulder  250  and the end wall  236 , and the portion of the nipple  235  axially between the ribs R″ and the end wall  236  is preferable smooth and purely cylindrical.  
         [0046]    Here, again, the springless seat cup  234  functions in the same manner as the springless seat cup  34  in that the ribs R″ bias the end wall  236  into engagement with the seat  15  for purposes of blocking fluid flow from the inlet  13  to the outlet  12  of an associated valve body I 1 . Furthermore, the reduced wall thickness T 6  in the shoulder region  250  relative to the wall thickness T 7  of the base portion  240  promotes flexure in the shoulder region. Accordingly, the seat cup  234  is selectively movable away from the seat  15  by rotational movement of the handle  24  of an associated valve body II, but returns to its normally closed position in engagement with the seat  15 , upon the handle  24  being released due to the biasing force of the ribs R″.  
         [0047]    The invention has been described with reference to preferred embodiments. Modifications and alterations may occur to others upon reading the preceding specification. It is intended that the invention be construed as including all such modifications and alterations insofar as they are encompassed by the appended claims as construed literally and/or according to the doctrine of equivalents.