Abstract:
A valve assembly for a clean-in-place operation includes a valve body with a valve seat and inner cavity. A shaft extends through the valve body and a stopper is connected to the shaft for movement between a normally closed position and an open position to permit cleaning fluid to enter and exit the inner cavity only through the valve. An actuator contacts the shaft for moving the stopper toward the open position. An air inlet extends into the inner cavity. A stop valve associated with the inlet prevents fluid from exiting through the inlet such that cleaning fluid only enters and exits the inner cavity through the valve seat A source of pressurized air opens the stop valve and causes drying air to enter the cavity and move the stopper toward the open position and supply the air to the processing system.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to processing systems including the transportation of semi-solid, liquid, and/or gaseous phases of foods and/or chemicals through conduits, into and out of holding tanks, and so on, during various manufacturing and/or packaging operations, and more particularly to a valve assembly and method for supplying gases or air to the processing system. 
     Systems for processing and/or transporting foods, chemicals and so forth between various locations in a processing plant can be as varied as the foods and chemicals produced and/or packaged. Such systems typically require a thorough cleaning after each batch or run. However, disassembling the vast array of conduits, holding tanks and other processing equipment in order to clean them would be a time-consuming and labor-intensive task, requiring more down time than run time. Accordingly, clean-in-place components have been introduced to minimize disassembly of the processing equipment. 
     In situ valves for providing air or gases during processing or after a cleaning operation are important components of the processing system since removal of product from the process lines before cleaning or another process run reduces contamination. Prior art valves of this type typically include a valve body connected to a pressurized source of drying air and a stopper that seals against a valve seat of the valve body when the drying air is removed. The purpose of the stopper is to prevent contaminants from entering the valve body and the pressurized air source. However, it has been found that contaminants can collect in the small areas between the valve seat and stopper, which may not be completely removed by the cleaning fluid. 
     Accordingly, it would be desirous to provide a valve assembly for clean-in-place operations that allow the small areas between the valve seat and stopper to be cleaned without the necessity of breaching the processing system. It would also be desirous to provide a valve assembly that is relatively simple in construction and operation. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with one aspect of the invention, a valve assembly configured for a clean-in-place operation includes a valve body with a lower surface, a valve seat extending into the valve body from the lower surface, an inner cavity extending into the valve body from the valve seat, and a separate inlet extending through the valve body and into the inner cavity. The valve assembly also includes a shaft extending through the valve body for reciprocal movement, a stopper connected to one end of the shaft for movement between a normally closed position wherein the stopper sealingly engages the valve seat and an open position wherein the stopper is spaced from the valve seat to permit cleaning fluid to enter and exit the inner cavity only between the valve seat and stopper, an actuator connected to the valve body, and a stop valve operatively associated with the inlet. The actuator includes a plunger adapted for contacting an opposite end of the shaft for moving the stopper to the open position when activated. The stop valve is in a normally closed position for preventing fluid from exiting through the inlet such that cleaning fluid only enters and exits the inner cavity through the valve seat when the plunger is in the open position. The stop valve is connectable to a source of pressurized air to thereby open the stop valve and cause air or other gas to enter the inner cavity with sufficient pressure to move the stopper toward the open position. 
     According to a further aspect of the invention, a valve assembly configured for a clean-in-place operation includes a valve body with a lower surface, an upper surface spaced from the lower surface, a valve seat extending into the valve body from the lower surface, and an inner cavity extending into the valve body from the valve seat. The valve assembly further includes a shaft extending through the valve body for reciprocal movement, a stopper connected to one end of the shaft for movement between a normally closed position wherein the stopper sealingly engages the valve seat and an open position wherein the stopper is spaced from the valve seat to permit cleaning fluid to enter and exit the inner cavity, and a biasing member located outside of the inner cavity and connected to the shaft to thereby bias the stopper toward the normally closed position. 
     According to yet another aspect of the invention, a clean-in-place method includes: connecting a clean-in-place valve to a conduit of a processing system, the valve including an inner cavity with a valve seat, and a stopper movably between a closed position in sealing engagement with the valve seat and an open position where the inner cavity is in fluid communication with the conduit; flowing cleaning fluid through the conduit; moving the stopper to the open position to cause the cleaning fluid to flow around the stopper, past the valve seat and into the inner cavity only from the conduit to thereby clean the stopper, valve seat and inner cavity; stopping the flow of cleaning fluid through the conduit; moving the stopper to the closed position; sending pressurized drying fluid into the inner cavity to thereby move the stopper to the open position and supply drying fluid to the inner cavity, the stopper and at least the conduit; and stopping the flow of pressurized drying fluid to thereby move the stopper to the closed position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing summary as well as the following detailed description of the preferred embodiments of the present invention will be best understood when considered in conjunction with the accompanying drawings, wherein like designations denote like elements throughout the drawings, and wherein: 
         FIG. 1  is an isometric view of a clean-in-place valve assembly in accordance with the present invention; 
         FIG. 2  is a front elevational view thereof; 
         FIG. 3  is a right side view thereof; 
         FIG. 4  is an exploded isometric view thereof; 
         FIG. 5  is a sectional view of the valve assembly taken along line  5 - 5  of  FIG. 2 ; 
         FIG. 6  is a sectional view of the valve assembly taken along line  6 - 6  of  FIG. 3 ; and 
         FIG. 7  illustrates a clean-in-place method showing a sectional view of the valve assembly at different operating positions in accordance with the present invention. 
     
    
    
     It is noted that the drawings are intended to depict only typical embodiments of the invention and therefore should not be considered as limiting the scope thereof. It is further noted that the drawings are not necessarily to scale. The invention will now be described in greater detail with reference to the accompanying drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings, and to  FIGS. 1-3  in particular, a valve assembly  10  for clean-in-place operations in accordance with a preferred embodiment of the invention is illustrated. The valve assembly  10  is particularly suited for introducing compressed drying air into a processing system for evacuating the contents of the processing system and/or drying the internal surfaces of conduits and other system components during a clean-in-place operation. Such processing systems include, without limitation, the transportation of semi-solid, liquid, and/or gaseous phases of foods and/or chemicals during various manufacturing and/or packaging operations. The valve assembly  10  is also especially suited for introducing a blanket or pocket of gas, a combination of gases or other fluids during regular processing operations. 
     The valve assembly  10  preferably includes a valve body  12  with a fluid inlet  14 , a stop valve  16  ( FIG. 2 ) located within the inlet  14 , a stopper  18  adapted for reciprocal movement between open and closed positions with respect to the valve body  12 , a shaft  20  connected to the stopper  18  for reciprocal movement therewith, and an actuator  22  connected to the valve body  12  and adapted for contacting the shaft  20  to thereby move the stopper  18  toward the open position when the actuator  22  is activated and allow movement of the stopper  18  toward the closed position when the actuator is deactivated. 
     With additional reference to  FIGS. 4-6 , the valve body  12  is preferably generally cylindrical in shape and includes an outer side surface  24  with a lower annular groove  26  formed therein for mounting the valve assembly  10  to a conduit or other system component in a well-known manner. An annular valve seat  28  is formed in a bottom surface  30  of the valve body for receiving the stopper  18  in sealing engagement. The seat  28  extends generally upwardly and inwardly and is in fluid communication with an inner cavity  32  formed in the valve body  12 . As best shown in  FIGS. 5-6 , the inner cavity  32  preferably has a first inner wall  34  that extends upwardly from the seat  28  and a second inner wall  36  that extends upwardly and inwardly from the first inner wall to form a generally conically-shaped inner cavity. The first and second inner walls  34 ,  36  are preferably coaxial with a central axis  38  of the valve body  12 . The conical shape of the inner cavity  32  ensures that fluid droplets and/or particles that may adhere to the inner wall  36  are efficiently removed when drying air is applied through the inlet  14 . 
     The inlet  14  is preferably formed as a cylindrical opening that extends downwardly and inwardly at an acute angle with respect to the central axis  38  of the valve body  12  from the outer side surface  24  of the valve body and intersects with the inner cavity  32 . A sleeve  40  preferably extends into the inlet  14  and protrudes outwardly and upwardly from the valve body  12 . The sleeve  40  can be attached to the valve body through any well-known connection means such as mutually engaging threads on the valve body and sleeve, press-fitting, adhesive bonding, interference fitting, and so on. 
     A depression  42  is preferably formed in the valve body  12  and extends downwardly from the upper surface  44  of the valve body. The depression  42  is preferably cylindrical in shape and includes a bottom wall  46  and continuous side wall  48  that extends upwardly therefrom. The depression  42  is preferably coaxial with the central axis  38  of the valve body  12 . A passageway  50  extends between the depression  42  and inner cavity  32  and is sized to receive the shaft  20  for reciprocating movement with respect to the valve body. An O-ring  51  is located within the passageway  50  and is in sealing engagement with the shaft  20 . 
     The shaft  20  extends from the stopper  18  upwardly through the inner cavity  32 , passageway  50 , and depression  42 . The shaft  20  preferably protrudes beyond the upper surface  44  of the valve body for engaging a plunger  52  of the actuator  22 . Preferably, the shaft  20  and stopper  18  are formed separately and connected together through well-known connection means. For example, the shaft can be constructed of stainless steel and the stopper can be constructed of an elastomeric material for sealing against the valve seat  28  when in the retracted or closed position. It will be understood that the shaft and stopper can be constructed of any suitable material. It will be further understood that the shaft and stopper can be integrally formed from a single piece of material without departing from the spirit and scope of the invention. The stopper  18  is preferably formed with an upper surface  55  that is complementary to the shape of the valve seat  28  to seal the inner cavity  32  against the ingress of foreign material during processing operations. An annular groove  54  is formed in the shaft  20  for receiving an upper spring retainer  56 . 
     As shown in  FIG. 4 , the upper spring retainer  56  is generally circular with a center opening  58  and a V-shaped slot  60  that extends outwardly from the center opening  58  to an outer edge  62  of the upper spring retainer. The slot  60  permits the upper spring retainer to be installed on the shaft  20  at the vicinity of the annular groove  54  through a snap-fit engagement. To that end, the upper spring retainer is preferably constructed of a material that is sufficiently resilient to allow expansion around the shaft  20  yet sufficiently rigid to stay in place and resist forces from a compression spring  64  when installed. 
     A lower spring retainer  66  preferably includes a generally flat base  68  that is positioned on the bottom wall  46  of the depression  42  and a boss  70  that extends upwardly from the base  68 . The boss  70  is preferably sized to receive the spring  64  with a lower end of the spring resting on the base  66 . A bore  72  extends through the boss  70  and base  68  and is sized for reciprocally receiving the shaft  20 . When assembled, the compression spring  64  exerts opposing forces on the lower spring retainer  66  and the upper spring retainer  56  to thereby force the shaft  20  and stopper  18  toward the closed position. Although a coiled compression spring is preferred, it will be understood that any device for biasing the shaft and stopper toward the closed position can be used, including but not limited to elastomeric blocks, pressurized air cylinders, flat springs, and so on. 
     The actuator  22  is of conventional construction and is preferably of the linear-actuator type. The actuator  22  preferably includes an air cylinder  74  with an air inlet  75  and outlet  77  ( FIG. 6 ). The plunger  52  reciprocates in and out of the cylinder  74  and is in a normally retracted position under biasing force from a compression spring  79  so that the stopper  18  is in the closed position against the valve seat  28  until the plunger  52  is activated. Once activated, the plunger  52  moves downwardly to exert an axial force against the shaft  20  against the biasing force of the spring  64  to thereby drive the shaft  20  and stopper  18  toward the open position. The actuator  22  is preferably activated when fluid pressure is applied through the air inlet  75 , such as air pressure. However, it will be understood that the actuator  22  can be of any well-known linear or rotary type including hydraulic, solenoid, motorized or mechanically activated actuators or any other well-known actuating means. 
     The actuator  22  is preferably mounted to a platform  76  which is in turn connected to the valve body  12  via spacers  78 . A pair of fasteners, such as bolts  80 , extend through apertures  82  in the cylinder  74  and openings  86  in the platform  76  and are preferably secured by cap nuts  84  located on an opposite side of the platform  76  for securing the actuator  22  to the platform. The platform is preferably disk-shaped and includes a central opening  88  for accommodating the plunger  52  ( FIGS. 5 and 6 ) of the actuator  22 . A pair of fasteners, such as bolts  90 , extend through apertures  92  in the platform  76 , the spacers  78 , and into threaded openings  94  formed in the valve body  12  for connecting the platform  76  to the valve body. 
     The provision of an actuator  22  separate from the valve body  12  simplifies the design, reduces manufacturing costs, and facilitates replacement of the actuator without removing the valve assembly  10  from the conduit or other system component to which it is attached, thereby eliminating the need to open the system and potentially expose it to contaminants. 
     As shown in  FIGS. 4 and 5 , the stop valve  16  is preferably embodied as a check valve, but may be in the form of a ball valve, butterfly valve, or any other configuration to stop the flow of fluid in at least one direction through the inlet  14 . When embodied as a check valve, the stop valve  16  is preferably of conventional construction and includes a valve seat  96  mounted in the interior  98  of the sleeve  40 , a plunger  100  mounted in the valve seat  96  for reciprocal movement with respect thereto, and a compression spring  102  extending between the valve seat  96  and plunger  100  for biasing the plunger  100  in a normally closed position where it sealingly engages the valve seat  96  in a well-known manner to thereby prevent fluid escape through the inlet  14  from the inner cavity  32  of the valve body  12 . When pressurized air is applied to the stop valve  16  from a source outside of the valve body  12 , the plunger  100  is forced toward an open position against biasing forces from the spring  102  to thereby supply drying air or other gases to the valve body  12  and the system to which it is connected. 
     Referring now to  FIG. 7 , a clean-in-place method  110  in accordance with the present invention is illustrated, with sectional views of the valve assembly  10  and attached conduit  112  shown at various operational stages. It will be understood that the same method can be used for introducing air, gas and/or other fluids into the processing system during normal processing operations, such as when it is desirable to introduce a blanket or pocket of the air, gas or mixture of gases and/or other fluids during processing without departing from the spirit and scope of the invention. 
     During a normal processing operation and prior to the clean-in-place method, the valve assembly  10  is in the closed position, as shown at  110 A, with the stopper  18  sealed against the valve seat  28  to thereby prevent processing fluids and/or particles from entering into the inner cavity  32  of the valve body  12 . In this position, the actuator  22  is in a retracted or non-activated position and the stop valve  16  is closed. As previously described, fluid and/or particles from the processing flow may become trapped or lodged within a lower dead space  114  between the conduit and valve assembly, and into the small areas at the intersection of the stopper  18  and valve body  12 . Because of the lower dead space  114 , the process flow is typically insufficient to dislodge the trapped contaminants. Accordingly, when the process flow has ended, a clean-in-place operation is initiated at  110 B wherein the actuator  22  is activated, as represented by arrows  116 , to thereby move the shaft  20  in a downward direction and unseat the stopper  18  and move it toward an extended or open position. When cleaning fluid is introduced into the conduit  112 , it will flow around the stopper  18 , valve seat  28 , and into the inner cavity  32 , as represented by arrows  118 . In this position, the stop valve  16  is closed. Preferably, cleaning fluid enters the inner cavity  32  only through the passageway created by the open stopper position. When the flow of cleaning fluid has stopped at  110 C, the actuator  22  is deactivated and the stopper  18  returns to its retracted or closed position against the valve seat  28 . Drying air is then introduced into the system at  110 D by supplying a source of pressurized air to the stop valve  16 , thereby causing the stop valve to open and introduce drying air into the inner cavity  32 . The pressurized air preferably acts with sufficient force to move the stopper  18  away from the valve seat  28  without activation of the actuator  22  and introduces the drying air into the conduit  112  and rest of the system, as represented by arrows  120 . In this position, the plunger  52  of the actuator  22  is spaced from the shaft  20 . When the clean-in-place operation has finished, as shown at  110 E, the pressurized air is removed from the stop valve  16  to thereby close the stop valve and cause the plunger  18  and shaft  20  to return to the closed position under biasing forces from the spring  64  ( FIG. 5 ). In this position, the valve assembly  10  is ready for further processing operations. 
     It will be understood that the term “preferably” as used throughout the specification refers to one or more exemplary embodiments of the invention and therefore is not to be interpreted in any limiting sense. It will be further understood that the term “connect” and its various derivatives as may be used throughout the specification refer to components that may be joined together either directly or through one or more intermediate members. In addition, terms of orientation and/or position as may be used throughout the specification relate to relative rather than absolute orientations and/or positions. 
     It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It will be understood, therefore, that this invention is not limited to the particular embodiments disclosed, but is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.