Abstract:
An aseptic valve or sanitary valve employs a floating plug situated within a cylindrical valve housing. The floating valve plug has a head that seats against an inlet opening, and has a stem and a generally conic foot that rests upon a diaphragm formed of a flexible, food-grade membrane. An actuator below the diaphragm urges the plug up to lodge against the inlet opening, and relieves force on the membrane and plug to open the valve. Spacer arms radiate from the stem or head of the plug, to keep the plug centered in the housing.

Description:
This is a continuation-in-part of and commonly-assigned U.S. patent application Ser. No. 12/883,518, filed Sep. 16, 2010, which is a continuation-in-part of application Ser. No. 12/766,009, filed Apr. 23, 2010, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to equipment for processing of liquids that must be kept aseptic, i.e., pharmaceuticals, dairy products, other food products for human consumption, beauty products, skin care products, and the like. The invention is more particularly concerned with sanitary valves of the type used in the dairy, food processing, and/or pharmaceutical industries, in which the flow of a fluid is to be regulated or diverted from one flow path to another. The invention is more directly concerned with diaphragm valves, that is, valves of the type in which a flexible membrane isolates the mechanical portions of the valve from the flow of fluid. The invention is more specifically concerned with a diaphragm valve of simple design and which can be cleaned and sterilized in place by the flow of a cleaning liquid through the valve. Sanitary diaphragm valves of this type can be used in a milk pasteurization line e.g. as a pressure regulating valve. These valve may also be employed as a drain valve for a sanitary tank to connect the tank to subsequent stage(s) in a processing line. 
     In order to ensure that the sanitary tank and conduit can be cleansed and sanitized between processes, the processing flow path, including any valves, need to be designed so that all components can be completely cleaned in place of any product by washing it and rinsing it with a cleaning fluid that must reach every point on the interior of the conduit, including every point in the valve cavities. No threaded connectors can be used anywhere that the liquid product flows, because of the difficulty in cleaning the threads. Any threads need to be sealed off and isolated from any contact with the processed fluid. In order to accommodate this requirement, the sanitary valves used in the dairy industry, food processing industries, pharmaceutical industry, have been complex and difficult to repair and maintain, and represent a significant capital expense. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an aseptic or sanitary diaphragm valve arrangement of simple construction, capable of being cleaned in place when installed in conduits for liquid food products, pharmaceuticals, beauty care products, or any other product which must be processed under sanitary conditions. The diaphragm valve must be capable of controlling flow and/or pressure of the liquid product, but should also be of simple, reliable, and sturdy construction so as to avoid the drawbacks of the prior art. 
     It is another object to provide an aseptic or sanitary valve that is employs a floating valve plug contained within a cylindrical valve body, and which avoids any need to machine or manufacture complex surfaces within the valve cavity. 
     Another object is to provide a valve design permitting the valve to be constructed of a minimum number of parts. 
     It is a further object to provide a diaphragm valve that is capable of reliably opening and closing to regulate the flow of fluids in the sanitary flow path. 
     According to one aspect of the invention, a sanitary or aseptic diaphragm valve is provided for use in connection with the outlet or drain of a sanitary tank or other vessel, such as a mixer or blender, in which a product is manufactured, processed or stored under sanitary conditions. The sanitary diaphragm valve is has a generally cylindrical valve body formed of a cylindrical wall, and with an upper plate at the upper end of the cylindrical wall. The plate has a circular inlet opening, whose circumferential edge forms a valve seat. There is also an annular plate disposed at a lower end of the cylindrical wall and this having an center opening or aperture. A tubular outlet pipe extends out from an opening in the cylindrical wall. 
     A floating valve plug is situated within said valve body along the cylindrical axis The valve plug has a head at its upper end, with the head having an upper valve face of round profile that is disposed to seat against the circumferential edge of the circular inlet opening. A valve plug stem aligns axially with the cylindrical wall and extends from the head downward within the valve body. A foot portion is formed at a lower end of said stem. To keep the plug aligned and centered in the valve body, there are angularly spaced radial arms or spokes that extend from either the head or the top part of the stem, or both, radially out to an inner surface of the valve body cylindrical wall. These keep the floating valve plug centered on the cylindrical axis the valve body. 
     A flexible diaphragm, e.g., a tough, food-grade silicone rubber sheet, is situated across the center opening of the annular plate at the lower end of the cylindrical wall. The foot of the floating plug rests upon it, but the valve plug foot is not attached to nor does it penetrate the diaphragm. 
     A valve actuator arrangement is disposed beneath the valve housing. This includes a valve actuator housing that has an annular flange at its upper end. The annular flange also has an open center. The annular flange is positioned against the annular plate of the valve body, and fastened to it, e.g., bolted or clamped, with the flexible diaphragm sandwiched between the annular flange and the annular plate. A valve actuator member situated within the valve actuator housing is movable over a given travel distance along the axis of the valve housing. A tip or upper edge of this valve actuator member pushes against the under side of the diaphragm. At the upper end of its travel distance, the actuator member urges the upper valve face of the plug against the circumferential edge, to wit, the valve seat, of the inlet opening. As the actuator member moves away from the upper end of its travel distance, force is relieved on the plug, and this permits the upper valve face of the plug to move away from the circumferential edge and permit flow of fluid through the circular inlet opening, into the valve body, and then out through the outlet pipe. 
     A closing force is applied to the valve actuator member to urge it and the associated valve plug to a raised position to effect seating of the upper valve face of the plug against the seat, or circumferential edge. This closing force can be controllably released or relieved, to allow the valve actuator member and valve plug to descent to a lowered position to permit opening of the plug member from said circular inlet. 
     In a favorable embodiment, the foot portion of the valve plug has a domed bottom surface that rests on said diaphragm. This facilitates the flow of the C.I.P. cleaning fluid over these surfaces during a cleaning operation. 
     The group of radial arms can comprise three spacer arms disposed at 120 degree intervals around the valve plug axis. 
     In preferred embodiments of this valve, the valve actuator housing includes a leakage-evident opening through its wall, so that if a leak develops in the diaphragm, it will create a visible drop of liquid at that opening. The leakage-evident opening need not be in any specific location, but must be in a zone of the valve actuator housing that is in fluid communication with the diaphragm. In the event that a tear or perforation occurs in the diaphragm, any process liquid will flow into the space beneath, out the opening, where it will provide a visible indication of a fault. 
     The valve actuator can include an air cylinder aligned with the valve housing, with an air piston located within the air cylinder. In one possible embodiment, the valve actuator member can be in the form of a rod that is affixed onto piston. An apertured plate in the cylinder has a central passage through which the valve actuator member passes. Compressed air is applied to the cylinder to raise the piston and actuator member. 
     In some preferred constructions, the foot portion of the plug may be frustoconic in shape. The circumferential edge or valve seat may have a bevel where the plug face seats against it. Air pressure can be controlled to permit the piston and the valve plug to descend a controlled amount so as to regulate flow of the liquid between cut-off and full flow. 
     In alternative embodiments, a spring may apply an upward closing force, and air pressure may be introduced to cause the piston to descend and compress the spring when it also relieves the closing force on the valve plug, for a normally-closed valve embodiment, in which air pressure is applied to open the valve. 
     Tri-clamps or equivalent sanitary clamp means may be used to attach the cylinder components and the diaphragms. The tri-clamp allows the valve to be partly disassembled for maintenance or repair on-station. The tri-clamp is a well known and available device, and need not be discussed in detail here. 
     The above and many other objects, features, and advantages of the arrangements of the present invention will become apparent from the ensuing detailed description of preferred embodiments of the invention, when read in connection with the accompanying Drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is perspective view of an aseptic or sanitary diaphragm valve according to one embodiment of the invention. 
         FIG. 2  is a cross sectional view thereof showing the housing, plug, diaphragm, and actuator. 
         FIG. 3  is a perspective view of the valve plug of this embodiment. 
         FIG. 4  is a perspective view of an alternative valve plug. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With initial reference to the embodiment illustrated in  FIGS. 1 to 3 , an aseptic valve or sanitary valve  10  of the present invention may be employed on a sanitary conduit, or may be employed at a lower drain of a sanitary tank or vessel, adapted for a dairy product, another edible product such as fruit juice, sauce or soup, or a pharmaceutical product for human or veterinary use, or a cosmetic, beauty-related, or dermatological creme or liquid. 
     The aseptic or sanitary valve  10  of this embodiment has one inlet and one outlet, and may be employed at the drain or outlet of a vertical tank. Other embodiments of this valve may have two or more controlled outlets. 
     In the sanitary diaphragm valve  10  of this embodiment, a cylindrical valve housing  12  is formed of a cylindrical wall that defines a hollow valve space within it. An upper valve portion  14  is affixed onto the upper end of the housing  12  and includes an inlet tube  16  and a top plate  18  that has a center opening. In this embodiment there is an upper flange  20  at the top of the inlet tube  16 , which attaches to the outlet or drain  22  of an associated sanitary tank (see  FIG. 2 ). A tri-clamp or similar sealing clamp  24  may be used to hold these components securely together, with a gasket or gland (not shown) fitted between them. 
     An outlet tube  26  extends from an outlet opening in the side wall of the valve body  12 . This discharges any fluid flowing to the valve body from the tank drain  22  into a subsequent stage (not shown). A bottom plate  28 , which is part of a valve actuator housing (an upper part  30  of which is shown in  FIG. 1 ), is secured, e.g., fastened with bolts or clamp, to the underside of the valve body  12 , details of which are shown better in  FIG. 2 . A tri-clamp or sealing clamp  32  can secure the upper valve actuator housing  30  to lower portions which are also shown better in  FIG. 2 , and will be discussed below. 
     There is a round inlet opening  34  at the center of the flat top plate  18 , with a beveled circumferential edge that serves as a seat for a valve plug  36  that is contained within the interior volume of the valve body or valve housing  12 . Here the valve plug  36  is a floating valve plug, that is, it is not firmly attached to other components within the valve housing. The valve plug is aligned axially within the cylindrical valve housing  12 , with a head portion  38  at its upper end. The head portion  38  has a valve face  40  at its upper side arranged to seat against the circumferential edge of the round inlet opening  34 . Here, the upper face  40  is coated with a sanitary, food grade synthetic rubber material, e.g., Vitan. Below the head is a stem  42  that is disposed at the axis of the cylindrical housing  12 . As shown in  FIG. 3 , the valve plug  36  has three radial spacer arms  44  that extend out transversely from the valve head  38  and loosely contact the interior cylindrical wall of the valve housing  12 . These spacer arms serve to keep the floating plug properly aligned within the housing. At the lower end of the stem  42  is a foot portion  46 . Preferably, the foot portion  46  has a curved, i.e., domed, lower side or sole  48 , which facilitates entry of C.I.P. fluid between the plug  36  and the associated flexible diaphragm on which it rests (to be described shortly). 
     At the lower end or base of the valve housing  12  is a lower ring flange  50  ( FIG. 2 ). The bottom plate  28  is secured to this ring flange  50 , here using threaded fasteners  52 . A flexible diaphragm  54 , e.g., a sheet of silicone rubber, is secured here, sandwiched between the ring flange  50  and the bottom plate  28 , as shown, and being exposed and subject to flexure at the aligned open centers of the flange  50  and bottom plate  28 . 
     A lower actuator assembly, here in the form of an air actuator, is attached onto the actuator housing upper portion  30 . A lower actuator housing  56 , which serves as an air cylinder, is secured, e.g., with a tri-clamp, to the upper portion  30 . An end plate  58  with air nipple N closes off the lower end of the cylindrical lower actuator housing  56 . An air piston  60  is situated in the cylindrical housing  56 . A valve actuator  62 , here in the form of a rod, extends upward from the piston  60  so that its upper tip contacts the under side of the diaphragm  54 . The cylindrical housing  56  is provided with an apertured mid-plate  64  and the actuator rod  62  passes through a center aperture in the plate  64 . An O-ring seal  66  is provided in the center aperture of the mid-plate to form a sliding seal between the mid-plate  64  and the actuator rod  62  so that air does not pass into the zone above the mid-plate. 
     Also, in the preferred embodiments, there is a leakage-evident detector hole  68  in one wall of the actuator housing, either in the upper or lower part, so long as it is in a zone between the mid-plate  64  and the diaphragm  54 . Any fluid that enters that zone, that is, the space below the diaphragm  54  and above the mid-plate  64 , will seep out a leakage detection hole  68  at the side of the housing, and provide a visible indication of possible diaphragm failure. When this occurs, it is a simple matter to remove the tri-clamp or tri-clamps, remove the bolts or other threaded fasteners  52 , and then change out the diaphragm  54 . The change out can be performed in the plant, and does not require removing the valve from the tank or piping, nor is factory maintenance or repair needed. Also, in this design the control air does not leak into the fluid product, as any air escaping past the seal  66  vents out through the hole  68 . 
     The travel distance or play of the plug  36  need only be one-half the radius of the valve inlet opening  30  and valve face  40  to achieve an unobstructed full flow of the liquid product. 
     In the design of this embodiment, there are no obstructed or closed off areas within the valve cavity within the valve housing  12 . All surfaces of the plug  36  are free and can be reached by the clean-in-place fluid. This allows the valve  10  to be cleaned in place by flowing a cleaning solution through it followed by a sterilizing fluid or steam. 
     A variation of the valve plug of this sanitary diaphragm valve of this invention is shown in  FIG. 4 . The parts of this plug that correspond with parts of the plug of  FIG. 3  are identified with similar reference numbers but raised by “100” and a detailed description of those elements need not be fully repeated. In this valve plug  136 , there is a sealing O-ring  140  seated in an annular groove on the sealing face  138  of the plug head, rather than having the entire face coated with a rubber sealing material. Here, as in the plug  36  earlier described, there are three spacer arms  144  disposed at one-hundred-twenty degree intervals. These may extend from the head  138  or from the stem. The body of the plug may be steel, or may be fabricated of a suitable food-grade, durable plastic resin, or of a high-performance ceramic, or other material. 
     In a normal orientation, where the valve  10  is located directly below a tank drain, gravity and fluid pressure of the process fluid will suffice to open the valve plug once air pressure is relieved. However, the valve  10  can also be oriented in a sidewards orientation in some applications, that is, with the axis of the valve housing  12  and the axis of the plug  36  being disposed horizontally. For such applications, there may be a magnet (not shown) situated at the tip of the actuator rod  62 , with the foot  46  of the plug being steel, so that the valve plug  36  moves in and out with the piston  60  and actuator rod  62 . 
     Also, the actuator can employ a spring (not shown) to bias the piston  62  and rod  62  up against the diaphragm  54  and foot of the valve plug  36 , for a normally-closed implementation. In that implementation, the compressed air may be applied to the upper side of the piston  60  to drive it down and overcome the spring pressure to open the valve. 
     In each of the described embodiments, the terms up, down, upper, lower, above and below are employed for simplicity of explanation in respect to the drawing figures. In any practical implementation, however, the valve assembly could be positioned in many other orientations. These terms as used in the specification and in the claims are not intended to limit the valve to any specific orientation. 
     The aseptic or sanitary diaphragm valves of this invention can be serviced in place, e.g., to replace any of the piston, plug or diaphragm, simply by removing the fasteners, disassembling the valve body, and replacing or changing out the diaphragms, piston(s) or any associated seals. 
     The sanitary diaphragm valve can be cleaned in place, as the construction of the valve flow space allows cleaning solution to reach every area of the valve cavity. 
     The construction of the valve is simple, but robust, without complex shapes of cavities or passageways, and with only a minimum number of required parts. Thus these sanitary diaphragm valves are inexpensive to manufacture, and simple to install and maintain. The valve is sturdy and reliable. 
     While the invention has been described with reference to a number of preferred embodiments, it should be understood that the invention is not limited only to those embodiments. Rather many variations are possible without departing from the scope and spirit of this invention, as defined in the appended Claims.