Abstract:
Apparatus for forming a fluidic seal such as in a clean service relief valve. In accordance with some embodiments, a ring-shaped sealing member has an annular main body portion with an innermost surface at an innermost diameter, an outermost surface at an outermost diameter and opposing top and bottom flat surfaces which respectively extend between the innermost surface and the outermost surface. An annular first projection extends away from the top flat surface in a first direction, and an annular second projection extends away from the bottom flat surface in an opposing second direction.

Description:
RELATED APPLICATIONS 
     This application makes a claim of domestic priority to U.S. Provisional Patent Application No. 61/819,888 filed May 6, 2013, the contents of which are hereby incorporated by reference. 
    
    
     BACKGROUND 
     Clean service pressure relief valves provide overpressure relief in clean service (fluid) applications, such as the food service, dairy, pharmaceutical, medical, chemical and other industries. In such applications, the pressurized fluid is transported through a conduit network. Pressure relief valves may be disposed at appropriate locations in the network to allow a bypass path to be established in the event of an overpressure condition. 
     Clean service applications may be subjected to strict regulatory requirements to reduce the risk of contamination to the transported fluids. Such applications may require extensive cleaning and sanitizing operations after an overpressure condition has been experienced in the network. 
     SUMMARY 
     Various embodiments of the present disclosure are generally directed to an apparatus for forming a fluidic seal, such as in a clean service relief valve. 
     In accordance with some embodiments, a ring-shaped sealing member has an annular main body portion with an innermost surface at an innermost diameter, an outermost surface at an outermost diameter and opposing top and bottom flat surfaces which respectively extend between the innermost surface and the outermost surface. An annular first projection extends away from the top flat surface in a first direction, and an annular second projection extends away from the bottom flat surface in an opposing second direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective representation of a clean service pressure relief valve constructed and operated in accordance with various embodiments of the present disclosure. 
         FIGS. 2A-2B  provide cross-sectional representations of a clean service pressure relief valve in accordance with some embodiments. The valve is in a normally closed position in  FIG. 2A , and in an open position in  FIG. 2B . 
         FIG. 3  shows a top plan view of a sealing member of the valves of  FIGS. 1-2 . 
         FIG. 4A  is a cross-sectional representation of the sealing member along line  4 A- 4 A in  FIG. 3 . 
         FIG. 4B  is a cross-sectional representation of an alternative configuration for the sealing member of  FIG. 3 . 
         FIG. 5  shows aspects of  FIG. 2A  in greater detail. 
         FIG. 6  is an exploded representation of components shown in  FIG. 5 . 
         FIG. 7  generally depicts operation of a coupling mechanism of the valves of  FIGS. 1-2  in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a perspective representation of a clean service pressure relief valve  100  in accordance with some embodiments. The valve  100  is provided to illustrate an exemplary environment in which various embodiments can be advantageously practiced. 
     The valve  100  is adapted to provide overpressure relief for a clean service application in which a clean fluid is transported through a conduit network (not separately shown). General features of the valve  100  includes a main body  102 , inlet port  104 , bypass path outlet port  106 , and a collapsible pin assembly  108  including a mechanically collapsible pin  110 , standoffs  112 , piston stops  114 , top support plate  115  and retention nut  116 . 
     The main body  102  is formed from separate lower, intermediate and upper housing members  118 ,  120  and  122 . These respective members are secured together using upper and lower coupling rings  124 ,  126 . The coupling rings are secured using respective fasteners  128 ,  130 . 
     Within the main body  102  is a normally closed valve assembly (not separately shown in  FIG. 1 ) that is in fluidic communication with the inlet port  104 . Inlet pressurized fluid at the inlet port  104  provides an upwardly directed force upon the valve assembly, which is retained in the normally closed position by the collapsible pin  110 . 
     At such time that the upwardly directed force exceeds a predetermined threshold, the pin  110  mechanically collapses in accordance with Euler&#39;s Law and the valve assembly moves to an open position. The valve assembly establishes an open bypass path to permit the fluid at the inlet port  104  to pass through the main body  102  and out the outlet port  106 . Although not shown, the outlet port  106  is adapted to be coupled to downstream conduit piping to divert the overpressurized fluid to a safe location, such as a storage tank, a drain, etc. 
     The three-piece construction of the housing main body  102  facilitates efficient disassembly and cleaning of the valve  100  prior to return of the valve to service after an overpressure event. Details regarding these and other features will be discussed below. 
       FIGS. 2A-2B  depict another clean service pressure relief valve  200  generally similar to the valve  100  of  FIG. 1 .  FIG. 2A  shows the valve  200  in the normally closed position, and  FIG. 2B  shows the valve  200  in an open position. As with the valve  100  of  FIG. 1 , the valve  200  of  FIG. 2  includes a main body  202 , inlet port  204 , bypass path outlet port  206 , and a collapsible pin assembly  208  including a mechanically collapsible pin  210 , standoffs  212 , piston stops  214 , top support plate  215  and retention nut  216 . It will be noted that, depending on spacing, there may be additional standoffs such as behind the pin  210 , but such has been omitted from  FIGS. 2A-2B  for clarity of illustration. 
     The main body  202  is formed from separate lower, intermediate and upper housing members  218 ,  220  and  222 . These respective members are secured together using upper and lower coupling rings  224 ,  226 . The coupling rings are secured using respective fasteners (not shown in  FIGS. 2A-2B ). A cylindrical insert  228  is housed within the upper housing member  222 . 
     A reciprocal valve assembly  230  is disposed within the main body  202 . The valve assembly  230  includes a cylindrical piston member  232  attached to an upper plate  234 . The upper plate  234  engages a lower end of the collapsible pin  210 . The piston  232  is shown to have a cup-shaped configuration, but other configurations including a solid configuration can be used. 
     The piston member  230  has a cylindrical outer wall  236  that is contactingly engaged by upper and lower annular sealing members  238 ,  240 . The upper sealing member  238  is compressingly disposed between the housing members  220 ,  222  by the coupling ring  224 . The lower sealing member  240  is compressingly disposed between the housing members  218 ,  220  by the coupling ring  226 . 
     As shown in the normally closed position of  FIG. 2A , the lower sealing member  240  provides a fluid-tight seal against the outer wall  236  of the piston member  232  to isolate the inlet port  204  from the outlet port  206  while the valve  200  is in the normally closed position. 
     Once the pressure of the pressurized fluid at the inlet port  204  provides sufficient upwardly directed force upon a lower surface  242  of the piston member  230 , the pin  210  mechanically collapses and the valve assembly  230  moves upwardly to the open position depicted in  FIG. 2B . More specifically, the pin  210  collapses into a captured, bent configuration as shown in  FIG. 2B  responsive to the upwardly directed force upon the surface  242  exceeding the yield limit of the pin  210 . The upwardly directed force is generally a function of the exposed surface area of the surface  242  and the pressure of the inlet fluid. 
     While a collapsible pin is shown, such is merely exemplary and not required. Other mechanisms can be used to maintain the valve  200  in the normally closed position and transition the valve to the open position, including but not limited to a spring mechanism, a rupture disc, etc. Moreover, while the valve is contemplated as constituting a normally closed valve, other configurations for a valve incorporating various aspects disclosed herein are also contemplated such as a normally open emergency shutdown valve, a flow regulating valve, etc. 
     The open position depicted in  FIG. 2B  establishes a bypass path for the pressurized fluid to pass from the inlet port  204  to the outlet port  206 . The valve assembly  230  is balanced so that the force upon the piston  232  from the inlet pressurized fluid at inlet port  204  will operate to open the valve irrespective of downstream pressure (if any) at the outlet port  206 . The upward movement of the valve assembly  230  is arrested by contacting engagement between the upper plate  234  and the piston stops  214 . The actual amount of movement can vary as required. The valve can be alternatively configured as a pressure differential valve so that the valve transitions to the open position in response to the pressure differential between the inlet and outlet ports  204 ,  206 . 
       FIG. 3  shows the lower sealing member  240  from  FIGS. 2A-2B  in greater detail. The upper sealing member  238  may be nominally identical to the lower sealing member  240 , or may have different dimensions and/or shape characteristics. The sealing member  240  is formed of a suitable elastomeric material compatible with the clean service application and includes an annular body portion  244  with a substantially rectangular cross-section. 
     Upper and lower radiused projections  246 ,  248  extend from the annular body portion  244 , as represented in  FIG. 4A . The radiused projections  246 ,  248  each have a half-circle hemispheric cross-sectional shape, although other shapes can be used. The upper and lower radiused projections  246 ,  248  are axially aligned as shown. Axially aligned projections can help ensure proper alignment of the seal since it will not matter which side is up during installation. 
     An interior sidewall  250  of the sealing member  240  is configured to contactingly engage the outer cylindrical sidewall  236  of the piston  232 . An exterior sidewall  252  of the sealing member  240  may similarly engage an interior surface of the clamp ring  226 . 
     The respective distances from the inner sidewall  236  to the projections  246 ,  248  is denoted in  FIG. 4A  as distance L 1 . The respective distances from the outer sidewall  252  to the projections  246 ,  248  is denoted as distance L 2 . L 2  is shown to be nominally equal to L 1  (e.g., L 1 =L 2 ), but such is merely exemplary and not required; for example, the sealing member is alternatively shown in  FIGS. 2A-2B  such that L 1 &gt;L 2 . 
     Similarly, the radius R 2  is shown in  FIG. 4A  to be nominally equal to R 1  (e.g. R 1 =R 2 ), but this is also merely exemplary and not required. For example, R 1  may be greater than or smaller than R 2 . Moreover, one side may have a first shape (e.g., circular as shown) and the other side may have a projection with some other shape (e.g., rectilinear, etc.). While the interior and exterior sidewalls  250 ,  252  are shown to be flat, other shapes, such as radiused (circular) shapes, can be used as desired. 
       FIG. 4B  illustrates an alternative sealing ring  240 A. The sealing ring  240  is similar to the ring  240  in  FIG. 4A  except that upper and lower projections  246 A,  248 A are axially offset. As noted above, it is contemplated that axially aligning the projections as in  FIG. 4A  will tend to allow the seal to be reversible, provided that the projections each share a common size and/or shape. An offset configuration as in  FIG. 4B  presents a seal that only fits “one-way,” which can be useful in applications where different sizes, shapes, diameters, etc. of the projections and/or the associated housing members are used. 
     It is contemplated that the sealing members  238 ,  240  will be reusable, so that the sealing members can be reinstalled and reused in a given application after disassembly and cleaning operations have been performed. Alternatively, the seals can be configured as one-time use items so that after an overpressure event, the main housing components can be subjected to appropriate cleaning operations and new, sterile sealing members can be installed. 
       FIG. 5  depicts the lower sealing member  240  in its installed position. It can be seen that an inner distal end portion  254  of the sealing member  240  projects from the housing members  218 ,  220  and into the interior of the main body  202 . The relative distance of projection of the end portion  254  may be sized in relation to the thickness of the sealing member  240  to ensure durability and sealing effectiveness. For example, it can be seen that the axial thickness of the sealing member  240  (vertical dimension) is greater than the length of the end portion  254  (horizontal dimension). Again, this is merely exemplary and not necessarily limiting. 
       FIG. 6  shows aspects of  FIG. 5  in a partially exploded representation. The mating housing members, in this case the upper end of the lower housing member  218  and the lower end of the intermediate housing member  220 , are provided with flat seating surfaces  260 ,  262  and associated annular grooves  264 ,  266 . The flat seating surfaces  260 ,  262  are configured to contactingly engage and seal against the main body portion  244  of the sealing member  240 . The grooves  264 ,  266  are configured to contactingly receive the radiused projections  246 ,  248 . Other shapes for both the seating surfaces and the grooves can be used, and the seal configuration can be conformed thereto as required. 
       FIG. 7  is a schematic representation of the clamping ring  226  from  FIG. 5 . Generally, the clamping ring  226  includes two clamp segments  270 ,  272  which are respectively rotatable via an intervening hinge  274 . Once the sealing member  240  is properly located between the respective housing members  218 ,  220  (See  FIGS. 5-6 ), the segments  270 ,  272  are opened, slipped around the circumference of the sealing member  240  and closed so as to bring distal ends  276 ,  278  into alignment. 
     A fastener such as  280  can thereafter be used to secure the distal ends  276 ,  278  and apply a suitable compressive force upon the sealing member  240  by engaging internal threads  282  in the respective clamp segments  270 ,  272 . The particular configurations of the clamp segments  270 ,  272 , the distal ends  276 ,  278  and the fastener  280  can vary as required. In some cases, a finger-operated fastener may be used as depicted in  FIG. 1 . It is contemplated albeit not necessarily required that the clamp  226  contactingly engages the outermost surface (e.g., surface  252 ) of the sealing member  240  (and similarly for sealing member  238 ). 
     Accordingly, the exemplary clean service pressure relief valves  100 ,  200  disclosed herein can operate in a sterile or other clean environment. The elastomer sealing members  238 ,  240  provide a novel, efficient construction that provides improved sealing due to the increased surface area contact between the sealing member and the respective housing members. The additional surface area provided by projections  246 ,  248  provides a tortuous path for the fluid to pass from one end of the sealing member to the other end. No o-ring type grooves are supplied to trap bacteria or contaminants. 
     The various housing and valve components can be formed of a suitable material such as 304 or 316 stainless steel. The valve can be downstream balanced and thus senses only upstream pressures, and downstream containment pressures will not change the set pressure at which the valve opens. It has been found that the disclosed valves can have an accurate setpoint of about +/−5% or less, and set pressures as low as about 2 pounds per square inch (psi) can be achieved. 
     The collapsible pin  110 ,  210  provides accurate and consistent opening performance. The pin is external to the interior flow of the pressurized clean service fluid and therefore the valve does not need to be opened in order to change the pin. Installation of a new replacement pin can be accomplished in seconds. 
     Other benefits of the valve include a visual indication of open position (e.g., a bent pin as in  FIG. 2B ). A fast opening time (usually within milliseconds) can be provided, and the valve is substantially unaffected by pulsating pressures or changes in ambient temperatures. Very precise set points can be established. 
     The radiused projections  246 ,  248  on the sealing members  238 ,  240  help to ensure proper alignment of the sealing member relative to the housing members, and vice versa, as well as to ensure centering of the sealing member with respect to the piston. This can be particularly useful in a clean service application where disassembly and reassembly of the valve may be required from time to time to meet regulatory requirements. It will be appreciated, however, that the various valve configurations can also be used in “non-clean” environments, due to the ease of disassembly. For example, valves can be easily disassembled and reassembled with different internal and/or external components to meet a variety of different operational environments. 
     It is contemplated that the seals may be reused after a disassembly and cleaning/sanitizing operation, or new seals may be provided for use each time. The seals facilitate precise overpressure control and subsequent maintenance operations to reset a triggered relief valve. The three-piece construction of the illustrative embodiments allows for quick disassembly, sterilization/sanitizing and reassembly. 
     While three-piece housings have been illustrated, any number of housing components can be used, including housings that use two mating housing components and a single intervening seal, housings with more than three housing components and additional seals, etc. In some cases, N housing components can be used with N−1 intervening sealing members of common or different configurations. 
     As used herein, the term “clean service” and the like will be understood consistent with the foregoing discussion to describe an operational environment with specified regulatory requirements concerning contaminant levels, such as but not limited to the food service, dairy, pharmaceutical, medical, chemical and other industries. While the transport of pressurized liquids has been contemplated, other forms of fluids such as gasses and mixtures of gas and liquid can be transported. Any number of operational temperatures are envisioned, including relatively cold (e.g., liquid nitrogen) and relatively hot (e.g., steam) applications are envisioned. 
     It is to be understood that even though numerous characteristics and advantages of various embodiments of the present disclosure have been set forth in the foregoing description, together with details of the structure and function of various embodiments, this detailed description is illustrative only, and changes may be made in detail, especially in matters of structure and arrangements of parts within the principles of the present disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.