Aseptic or sanitary top hat diaphragm valve

An aseptic valve or sanitary valve has an elongated tubular, cylindrical valve housing, with one or more top-hat diaphragms and associated valve plugs positioned transverse to the axis of the tubular valve housing. An actuator urges the stem and head of the valve plug upward so that the associated diaphragm is urged against a valve seat to close the valve. The actuator also moves these elements downward and away from the seat to open the valve. Plural valve arrangements can be joined end to end to accommodate multiple flow paths.

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 directed to 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 also 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. Moreover, it has been desired to provide a sanitary valve of a type in which multiple valves can be joined to one another to form a multiple valve for controlling fluid flow over a number of possible flow paths.

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.

Also, because pumping losses occur when the process fluids pass through a valve, it is also desirable to design the sanitary valve so that it presents a minimum of obstruction to the flow of the process fluid.

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 employs a valve plug contained within a membrane that separates it from the process fluid, but with a minimum of obstruction to the flow of the fluid, and does not require complex surfaces within the valve cavity.

Another object is to provide a valve design permitting the valve to be constructed of linear design, and which is capable of combining with a similar valve to construct a multiple valve that can direct the fluid to any of a number of alternative flow paths.

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 flow of a liquid food product, a pharmaceutical or other fluid that needs to be processed under sanitary or sterile conditions. The sanitary diaphragm valve is has an elongated tubular (i.e., generally cylindrical) valve body formed of an elongated tube or pipe, with flange rings at its two ends. The ends may be closed off, using a seal disk held by a clamp to the respective flange ring, or the end may be connected to a tubular conduit for the fluid, or may be connected to the tubular valve body of a similar sanitary diaphragm valve. The valve mechanism(s) are formed of an upper tube stub and a lower stub joined to opposite sides of the tubular body and positioned on a valve axis that is transverse to the longitudinal axis of the tube body, where each tube stub has a flange ring at its end. An annular valve seat is positioned within the upper tube stub. An actuator is attached onto the lower tube stub and has a movable member that is capable of motion for a limited distance along the valve axis. The actuator has a flange ring mating against the flange ring of the lower tube stub. The actuator may be controlled by compressed air, or may in some cases be manually operated.

A top hat sanitary diaphragm is formed of a flexible elastomeric material and is disposed transversely across the interior of the tubular valve body, aligned along said valve axis. The top hat diaphragm generally resembles a stove-pipe men's hat of the type worn in the nineteenth century, and has a lower annular brim portion that retained between the annular flange rings of the lower tube stub and the actuator, a cylindrical stove-pipe portion extending from the lower annular portion, along the valve axis across tubular valve body into the upper tube stub, and an upper disk portion that extends across the cylindrical portion of the diaphragm and reaches the valve seat. The diaphragm may be formed of a tough, food-grade silicone rubber.

A plug member is positioned within an interior of the top hat sanitary diaphragm. This plug member has a stem aligned along the valve axis, and has a lower end affixed onto the movable member of the actuator and also has a head portion disposed against the disk portion of the diaphragm. The action of the actuator in one direction urges the disk portion against valve seat to close the valve, and in the other direction moves the disk portion of the diaphragm away from the valve seat to open the valve.

The stem portion of the plug member should have a diameter substantially smaller than the interior of the cylindrical portion of the diaphragm, while the head portion should have a diameter that substantially matches the disk portion of the diaphragm.

The actuator, e.g., a pneumatic cylinder, favorably has an opening through its outer wall that serves the purposes of providing visible evidence of leakage if there is a failure of the diaphragm, and also permitting communication between the interior of the cylindrical portion of the top hat diaphragm and ambient air pressure outside the valve. That is, the pressure within the cylindrical part of the top hat diaphragm remains at atmospheric pressure while the pressure outside the cylindrical portion is determined by the pressure of the process fluid. Accordingly, the top hat diaphragm flattens, providing a small profile across the valve body, and minimizing any obstruction to the flow of the process fluid. The head of plug member is favorably conic in shape with its narrow end joined to the stem.

There can be a third tube stub, or further similar tube stubs on one side or another of tubular valve body at position(s) displaced from the first-mentioned valve axis and between the first and second ends of the valve body. The additional tube stub or stubs each have respective flange ring(s) at their end. These may serve as inlet or outlet ports for the fluid that is controlled by the valve.

There may be additional valve mechanisms, each with a pair of tube stubs, plug, top-hat diaphragm, valve seat and actuator, so that the valve may be employed for diverting the fluid from one flow path to another. Also two or more of these tubular-body sanitary diaphragm valves may be joined end-to-end to form a multiple valve arrangement, permitting control of the flow of the fluid over a multiple of possible flow paths.

In a favorable embodiment, the diaphragm is designed to allow for the flow of C.I.P. cleaning fluid over the internal valve surfaces during a clean-in-place cleaning operation.

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 may 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 and out the opening, where it will provide a visible indication of a fault.

The valve actuator can take the form of an air cylinder aligned transverse with the tubular valve body, with an air piston located within the air cylinder. This may be arranged so that compressed air holds the valve closed, or arranged to be spring-closed so that compressed air is applied to open the valve.

Tri-clamps or equivalent sanitary clamp means may be used to attach the cylinder components, actuators, connected piping, and 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.

In the description and claims, terms of orientation such as upper, lower, above, and below are used only for convenience in describing the invention in association with the accompanying Drawing figures. It should be understood that this diaphragm valve can be installed and operated in any of a wide variety of orientations.

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.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With initial reference to the embodiment illustrated inFIGS. 1 to 3, an aseptic valve or sanitary tubular, top-hat diaphragm valve10of the present invention may be employed on a sanitary conduit, or may be employed in connection with 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 valve10of this embodiment is formed with a tubular valve body or valve housing12, here embodied as a straight length of cylindrical tubing; here for purposes of explanation and illustration the tubular valve body12is oriented horizontally and defines a horizontal tube axis. There are tube stubs joined to the main valve body to serve as inlet port(s) and controlled or valved outlet ports, including a first upper tube stub14and first lower tube stub16disposed opposite one another along a valve axis (here a vertical axis) that is transverse to the main tube axis; at a distance displaced from them, a second upper tube stub18and second lower tube stub20are disposed opposite one another and are oriented along a second valve axis that is also transverse, i.e., at right angles, to the main tube axis. Between them is a third upper tube stub17, which can serve as an un-gated inlet port. In this embodiment, the tube stubs are of the same diameter as the main tubular body12, but that is not required for all embodiments. The tubular valve body12also has a left end22and a right end24. At each of the tube ends22,24and the ends of each of the tube stubs14,16,17,18, and20there is a flange ring26formed on the associated member, and these are adapted for fitting a Tri-Clamp or other clamping member to join that member to a pipe or another element such as an air cylinder actuator, or to another similar diaphragm valve. Favorably, the valve body and tube stubs can be three-inch inside diameter stainless steel tubing.

Valve seats28are fitted within the two upper tube stubs14and18. An actuator30, e.g., an air-actuated pneumatic cylinder, may be attached onto either or both of the lower tube stubs16and20, using a Tri-clamp32.

As shown inFIG. 2(see alsoFIG. 5) the valve employs a diaphragm40that is in the shape of a top hat or a stove-pipe hat, and is formed of a suitable food-grade rubber, e.g. a silicon rubber or the equivalent. The top hat diaphragm40at its base has a planar annular flange42forming the “brim” of the hat, a cylindrical portion44that rises from the annular flange an forms the “crown” of the hat, with an upper disk member46extending across the top of the cylindrical portion44. The brim or annular flange42extends outward from the base of the cylindrical portion44and is captured between the flange ring26of one of the lower tube stubs and the flange ring of an associated actuator. A stainless steel washer58is bolted through the top disk46, using a bolt50with an associated seal ring, as shown.

As also shown inFIG. 2, a valve plug52extends vertically within the interior of the diaphragm cylindrical portion, with a head54, in the shape of an inverted cone, that receives the bolt50and is affixed against the diaphragm top disk46and stainless steel washer48. A stem56, of narrow diameter, extends down from the narrow nose end of the cone-shaped head54and terminates at a piston58that is a part of the associated air-cylinder actuator30.

As better shown inFIG. 3, there are seal disks60, favorably of a food grade stainless steel, that terminate any unused openings or ports in the valve. In the embodiment to be described shortly, the seal disks60are used to terminate the left and right ends22and24of the tubular valve body12. In this illustration ofFIG. 3, a dummy plug62and an associated top hat diaphragm40are positioned in the left-side upper and lower tube stubs14and16to close off one unused outlet port. Here the associated lower tube stub16is closed off using a seal disk60held in place with a tri-clamp32. A leakage-evident opening64is present in the lower tube stub20above the associated actuator30, and this can serve to provide a visible indication of leakage of the process fluid in the event there is a perforation, tear, crack or other failure of the associated diaphragm40. This also communicates the interior of the top hat diaphragm cylindrical portion44with the outside ambient, so that the pressure within the interior of the diaphragm40is at a pressure lower than the fluid pressure of the process fluid within the tubular valve body.

A practical valve arrangement according to the present invention is shown inFIG. 4, in which the diaphragm valve10has an inlet pipe70supplying the process fluid, e.g., milk, fruit juice, soup, or a pharmaceutical, to the center tube stub17, with a tri-clamp32joining the pipe70to the tube stub17. A seal ring, e.g., gasket or gland, is provided between a flange ring on the pipe70and the flange ring26of the tube stub17, but the seal ring is not shown in this view. Gated outlet pipes72and74are mounted by means of tri-clamps32and associated seal rings to the upper tube stubs14and18, respectively. These outlet pipes72and74lead to a main flow path and a diverted flow path for the process fluid. The valve elements for the left and right gated outlet pipes72and74are each constituted by a top hat elastomeric diaphragm40and an associated valve plug52, with a valve seat28positioned in each associated upper tube stub14and18, as described earlier. The ends22and24of the tubular valve body12are closed off by sealing disks60, each held in place with a respective tri-clamp.

In this illustration, the left plug52and diaphragm40are urged upward so that the diaphragm closes against the associated valve seat28. The right plug and diaphragm are urged downward, as shown, so that the upper part of the diaphragm40is moved away from its associated valve seat28, permitting flow of the process fluid, as shown by arrows in this view. In order to divert flow from the outlet tube72to the other outlet tube74, compressed air is applied to the right actuator30to raise the piston58and the associated plug52and top hat diaphragm40, and then air pressure is relieved from the left actuator to move the left piston58, plug52and diaphragm40away from the left valve seat28.

FIG. 5shows top hat diaphragm40so that the underside of the flange42is visible, showing the open base and hollow interior of the cylindrical portion44, with the center opening into which the plug52is fitted.

Because the interior space within the top hat diaphragm is open to ambient pressure, as discussed before in respect to the opening64, the sides of the cylindrical portion44flatten together in the presence of the process fluid, which is under pressure while in the system. Accordingly, as shown inFIG. 6, the top hat diaphragm takes on a reduced profile in the flow direction of the process fluid, and imposes only a minimal resistance to the flow of the process fluid. The wide end of the conic head54holds the disc portion46of the diaphragm to its full width, but the narrow stem56allows the center part of the top hat diaphragm to flatten to a much smaller profile, as shown.

FIG. 7illustrates a second of many possible configurations. In this arrangement, two of these tubular valves are joined together end-to-end to create a multiple valve, i.e., a valve with multiple alternative outflow paths. A first top-hat diaphragm valve10at the left is joined to a second top-hat diaphragm valve110at the right, with the right end24of the left valve10being joined (by use of a tri-clamp) to the left end of the right valve110. The second valve110is of the same construction as the first (i.e., left) valve arrangement10and as shown and disclosed in respect toFIG. 4. Elements that are employed in the second valve110are identified with the same reference numbers as for the corresponding elements discussed earlier, but raised by 100. Sealing disks60are fitted onto the two outer ends of the tubular valve bodies, and a sealing disk is fitted also onto the tube stub117, which is inactive. The inlet pipe70is fitted onto the inlet tube stub17, and first through fourth outlet pipes74,72,76and18are fitted onto the upper tube stubs14,18,114, and118, respectively. There are four valve closure mechanisms formed respectively of diaphragm40and plug52, diaphragm40A and plug52A, diaphragm140and plug152, and diaphragm140A and plug152A, as shown from left to right in this view. Each plug is moved by means of a piston of an associated actuator30joined to the respective lower tube stub16,20,116and120, and there are air hoses80leading to each actuator cylinder from a control box (not shown) that supplies control air. This illustration shows the second valve closure mechanism (plug52A and diaphragm40A) being drawn down to open the pathway through outlet pipe72, with the other valve closure mechanism being urged upwards to the closed position. The supply of control air can be changed to close the flow path to outlet pipe72and open one (or more) of the flow paths through outlet pipes74,76, or78.

Other configurations are possible without departing from the main principles of construction or operation of this diaphragm valve. The tubular valve body12may be of a non-circular section, i.e., oval or oblong, and although this embodiment employs straight tubing for the valve body, the valve body12could be curved in some embodiments.FIG. 4illustrates an arrangement in which the valve arrangement has its actuators30above and the inlet and outlet tubes70,72,74beneath. The reference numbers employed here identify the same elements as inFIG. 4, and a detailed description need not be repeated.

While terms of orientations such as horizontal, vertical, upper, lower, right and left have been employed here, these are meant only for convenience in describing the invention in terms of the Drawing Figures. It should be understood that the diaphragm valve of this invention is not to be limited to any particular orientation.

While the invention has been described with reference to selected 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.