Leak-free rising stem valve with ball screw actuator

A rising stem valve with a magnetic actuator having an outer and as inner magnet assembly that are magnetically coupled to each other so that the inner and outer magnet assemblies rotate together and a ball screw that is connected to the rising stem valve and that converts rotary to reciprocal motion. The inner magnetic cartridge assembly and valve body comprise a sealed lower section that is completely sealed to the outside environment.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the field of valves, and more specifically, to a rising (or reciprocating) stem valve that incorporates a ball screw mechanism and prevents leakage offend to the atmosphere.

2. Description of the Related Art

Attempts have bean made to provide leak-free protection for rising stem valves, which include gate, globe, knife and needle valves. Currently, metal bellows are employed around rising stems in these valves, especially when the valves are handling hazardous fluids. The bellows surround the stems and their associated packings to contain any leaks that penetrate through the packing assembly. Bellows, however, are not inherently leak-free because they eventually tail as metal fatigue begins to form cracks in the bellows. This kind of failure may result in a catastrophic release of hazardous fluid because when the bellows fails, the packing leaks without restraint.

An alternative, inherently leak-free technology is needed to replace bellows in places like chemical plants, refineries, paint factories, and cryogenic applications, where rising stem valves are integral to the functioning of the plant itself. This alternative technology must provide the advantage ox completely containing any leakage of fluids from valves.

A number of patent applications have been filed for valve actuators that mitigate stem leakage through the use of a magnetic interlock. These actuator chambers either enclose the dynamic seal that is present in every valve around the stem of the valves or eliminate the need for the seal entirely. This dynamic seal is known as a packing or mechanical seal. The magnetic interlock is employed to transmit force from the outside to the inside of the actuator chamber, thus avoiding the penetration of the chamber wall by a mechanical stem actuator. Penetration of the chamber wall would nullify the purpose tor the chamber in the first place—to enclose the dynamic seal around the stem and prevent leakage from the seal.

The problem with various proposed magnetic actuators is that the amount of force transmitted by the magnets is not adequate to ensure the proper function of the valve. If an actuator is designed to provide adequate force to open and close the valve, the magnet coupling is so large as to make it impractical. Even with the use of modern rare-earth magnets such as Neodymium Iron Born and Samarium Cobalt, the ability to transmit adequate force to the valve stem is still difficult. The forces provided by the magnets are only a fraction (usually less than 20%) of the force that a mechanical stem actuator can provide. This does not give the valve operator the confidence that his valve can be opened or closed under situations where high force is required, such as high fluid pressure, dry seals, or debris in the fluid path.

Rather than increasing force by building ever larger magnetic couplings, the present invention incorporates a ball screw assembly that multiplies the force supplied by the inner magnetic coupling while at the same time converting that force from rotary to reciprocal motion. For example, a torque of 120 in-lbs. can be converted to an axial force of 2000 lbs. or more by using a typical 0.75″ ball screw with a lead of 0.5″, the lead being the distance that the screw moves axially with each full rotation of the ball nut. This allows the use of a much smaller magnetic coupling. The reduction in size is desirable because the magnetic coupling is the most expensive component of the actuator.

Through the incorporation of a ball screw subassembly, the present invention provides a magnetically activated valve actuator that can be used in the harshest conditions. Magnetic actuation is no longer appropriate for light applications only. Rather, it is a robust alternative that provides force to the stem that is equivalent to that of low- and medium-pressure dynamically sealed stemmed valves. This innovation is most needed in places like chemical plants, refineries, and pipelines where valves are the central workhorses of the plant or pipeline.

In addition to increasing force and/or decreasing the size of the magnetic coupling, the present invention has the advantage of completely containing any leakage of fluids from the valve bonnet. The present invention is intended to be coupled to valves that are used in hazardous fluid or chemical applications, where stem leakage poses a pollution threat to the outside environment or a safety threat to personnel working nearby. At the very least, leakage from stem packings results in the loss of product, which can be costly. Fugitive emissions account for over 125,000 metric tons of lost product per year in the United States alone. Of this amount, the percentage of fugitive emissions that come from valve stems is estimated to be between 60% and 85%.

The threat posed to the environment by leaking valve stems is great, particularly when the product that is leaked is a fugitive emission, that is, a leaked or spilled product that cannot be collected back from the environment. An example of a fugitive emission would be methane leaking from a valve on a pipeline or in a refinery, in which case the methane immediately goes into the atmosphere and cannot be recaptured. Another example would be crude oil leakage from a valve on an offshore rig, where the oil is earned away by ocean currents and cannot be recovered.

Safety requirements are becoming more stringent with each passing year. Personnel who are required to work near hazardous chemicals—such as operators in a petrochemical plant—are subject to injury from leaking valve stems, especially from reciprocating stems where the hazardous material inside the valve is transported to the outside environment via the stem as it retracts from the valve body. For example, if the valve is handling chlorine, a leaking stern transports it to the outside environment, where it becomes hydrochloric acid when it reacts with moisture in the air. This acid corrodes the stem, which makes it even more difficult to seal over time.

The magnetic actuator of the present invention safely encloses the stem of all reciprocating stemmed valves because it is able to transfer torque through the enclosure magnetically without physically penetrating the enclosure itself. Magnetic actuators have been proposed previously for rotating stem valves. For these devices, the torque is magnified inside of the actuator chamber by the use of a worm gear or a planetary gear set. In the case of rising stem valves, however, the torque must also be converted to reciprocal motion. The present invention proposes the use of a ball screw, which not only magnifies the force of the magnetic actuator, but also converts the rotary motion to reciprocal motion.

Currently, ball screws are being used to actuate high-pressure gate and globe valves where large forces are required to move the valve stem up and down. For example, in a high-pressure, ASME Class #2500 gate valve, the fluid pressure on one side of the gate may be in the range of 5,000 psi, pushing the gate against the downstream valve seat with several tons of force. To lift the gate, the stem must provide as much as 20,000 lbs. or more of lifting force.

Ball screws and helical spline actuators are employed in high-pressure, self-contained hydraulic, electric, or pneumatic actuators, where the actuation force is transferred into the sealed chamber or outer casing by means of electrical wires, hydraulic fittings, or pneumatic fittings. The hundreds or thousands of ft-lbs. of torque required to move these valve stems cannot be transferred magnetically in a practical way; therefore, it has not been obvious that magnetic couplings could ever be coupled to ball screws to actuate rising stem valves. Instead, the automated versions of these valves are self-contained; that is, the mechanical energy required to actuate these valves is provided internally by hydraulic, electric, or pneumatic means.

The present invention cannot be used tor the applications described above for the reasons stated; however, it can be used for low- and medium-pressure applications known as ASME class #150, #300, and #600 valves. The ball screw specified in the present invention is much smaller in diameter than those currently being used to actuate high-pressure valves. This accomplishes three things: (1) the lower torque requirement allows the use of magnetic actuation rather than self-contained power (that is, the transfer of torque through the sealed chamber by means of a magnetic coupling is now possible); (2) the smaller diameter ball screw allows for more room for the inner magnetic cartridge, making it possible to consider high-temperature Alnico magnets tor use at temperatures up to 950 degrees Fahrenheit; and (3) the mechanical advantage provided by the smaller diameter ball screw (i.e., the ratio of reciprocal force over supplied torque) is much greater than that of the larger high-pressure ball screws when given the same amount of axial travel (or lead) per rotation. (A larger diameter screw has a larger circumference per rotation, which results in a greater axial movement per rotation than with a smaller screw that has the same lead angle. Thus, the smaller screw must have a steeper lead angle in order to supply the same amount of axial travel per rotation as a larger diameter screw. A steeper lead angle increases the efficiency of the screw when converting rotary motion to reciprocal motion.) These advantages are not present in any of the prior art valves that utilize a magnetic actuator.

BRIEF SUMMARY OF THE INVENTION

A rising stem valve comprising: a pneumatic actuator assembly comprised of a pneumatic actuator, an upper ball nut, and a ball nut mount, wherein the upper ball nut threads into a bottom end of the ball nut mount, and the ball nut mount threads into a pneumatic piston, the upper bah nut being configured to move up and down with the pneumatic piston; a valve body comprised of a top flange; a gate assembly with a lower ball screw, a gate mount and a gate, wherein a bottom end of the lower ball screw resides within the gate mount, and a lower portion of the gate mount is inserted into a guide channel in the gate; an inner magnetic cartridge assembly comprised of a magnet housing and an inner magnetic cartridge, wherein the inner magnetic cartridge is comprised of an inner magnet carrier around which a plurality of inner magnets are arranged radially and spaced apart from one another, and wherein the inner magnetic cartridge resides within the magnet housing; an outer magnetic assembly comprised of an outer magnet carrier and an outer magnet top that is fixedly secured to the outer magnet carrier, a plurality of outer magnets held within the outer magnet carrier, the outer magnets being magnetically coupled to the inner magnets so that when the outer magnets rotate, the inner magnets rotate in a same direction; and an upper ball screw with a top end that threads into the upper ball nut so that the upper ball screw rotates as the ball nut moves linearly up and down, and a bottom part that is coupled to the outer magnet top so that the outer magnet top rotates with the upper ball screw; wherein the gate assembly is contained within the valve body, and the inner magnetic cartridge assembly and valve body comprise a sealed lower section that is completely sealed to an outside environment; wherein the outer magnetic assembly is secured to the scaled lower section; wherein the magnet housing is fixedly attached to the top flange of the valve body; wherein an inner ball nut is locked rotationally to the inner magnet carrier; and wherein the inner ball nut is configured to cause the lower ball screw to move linearly up and down within the valve body as the inner ball nut rotates.

In a preferred embodiment, the inner magnets are situated within channels in the inner magnet carrier. Preferably, the inner magnetic cartridge assembly further comprises a spacer that abuts up against a bottom surface of the inner magnet carrier, and a spring ring that is situated on an upper surface of the spacer between the spacer and the inner magnet carrier. A first upper tapered roller bearing is preferably situated inside of the magnet housing directly underneath a ceiling of the magnet housing. A first lower tapered roller bearing is preferably situated inside of the magnet housing between the spacer and a compression nut.

In a preferred embodiment, the spacer is configured to rotate along with the inner ball nut and the inner magnet carrier. Preferably, the outer magnetic assembly further comprises a second upper tapered roller bearing and a second lower tapered roller bearing, the second upper tapered roller bearing being situated inside a bottom end of the outer magnet top and the second lower tapered roller bearing being held in a recess on an inside of the outer magnet carrier. The second upper tapered roller bearing preferably comprises an outer raceway that is constrained by the outer magnet top and an inner raceway that is constrained by the magnet housing, and the second lower tapered roller bearing preferably comprises an outer raceway that is constrained by the magnet housing and an inner raceway that is constrained by the magnet housing.

In an alternate embodiment, the present invention is a rising stem valve comprising: a manual actuator assembly comprised of a handle assembly and a manual actuator mount assembly; a valve body comprised of a top flange; a gate assembly with a lower ball screw, a gate mount and a gate, wherein a bottom end of the lower ball screw resides within the gate mount, and a lower portion of the gate mount is inserted into a guide channel in the gate; an inner magnetic cartridge assembly comprised of a magnet housing and an inner magnetic cartridge, wherein the inner magnetic cartridge is comprised of an inner magnet carrier around which a plurality of inner magnets are arranged radially and spaced apart from one another, and wherein the inner magnetic cartridge resides within the magnet housing; and an outer magnetic assembly comprised of an outer magnet carrier and an outer magnet top that is fixedly secured to the outer magnet carrier, a plurality of outer magnets held within the outer magnet carrier, the outer magnets being magnetically coupled to the inner magnets so that when the outer magnets rotate, the inner magnets rotate in a same direction; wherein the outer magnet top is configured to rotate as the handle assembly rotates; wherein the gate assembly is contained within the valve body, and the inner magnetic cartridge assembly and valve body comprise a sealed lower section that is completely sealed to an outside environment; wherein the outer magnetic assembly is secured to the sealed lower section; wherein the magnet housing is fixedly attached to the top flange of the valve body; wherein an inner ball nut is locked rotationally to the inner magnet carrier; and wherein the inner ball nut is configured to cause the lower ball screw to move linearly up and down within the valve body as the inner ball nut rotates.

In a preferred embodiment, the inner magnets are situated within channels in the inner magnet carrier. Preferably, the inner magnetic cartridge assembly further comprises a spacer that abuts up against a bottom surface of the inner magnet carrier, and a spring ring that is situated on an upper surface of the spacer between the spacer and the inner magnet carrier. A first upper tapered roller bearing is preferably situated inside of the magnet housing directly underneath a ceiling of the magnet housing. A first lower tapered roller bearing is preferably situated inside of the magnet housing between the spacer and a compression nut.

In a preferred embodiment, the spacer is configured to rotate along with the inner ball nut and the inner magnet carrier. Preferably, the outer magnetic assembly further comprises a second upper tapered roller bearing and a second lower tapered roller bearing, the second upper tapered roller bearing being situated inside a bottom end of the outer magnet top and the second lower tapered roller bearing being held in a recess on an inside of the outer magnet carrier. The second upper tapered roller bearing preferably comprises an outer raceway that is constrained by the outer magnet top and an inner raceway that is constrained by the magnet housing, and the second lower tapered roller bearing preferably comprises an outer raceway that is constrained by the outer magnet carrier and an inner raceway that is constrained by the magnet housing.

In one embodiment, the handle assembly comprises a handle and a key, and the key fits into a first keyway in a center hole of the handle and a second keyway in the outer magnet top.

REFERENCE NUMBERS

7Pneumatic actuator mount assembly

9Inner magnetic cartridge assembly

13Manual actuator mount assembly

25Lower ball screw

29Upper ball screw

66Outer magnet top

72Mount can divider

76Alternate embodiment of mount can (manual actuator)

104Valve gate guide channel

105Valve gate guide

108Sealed lower section

111Pneumatic shaft guide

DETAILED DESCRIPTION OF INVENTION

FIG. 1is a perspective view of the present invention fully assembled with a pneumatic actuator. This figure shows the major parts of the invention, namely, the pneumatic actuator37, pneumatic actuator assembly6, pneumatic piston120, ball nut mount70, pneumatic actuator mount assembly7, mount can73, magnet housing60, and valve body11. As shown in the figures, the magnet housing60serves as a barrier between the inner and outer magnets61,69of the magnetic actuator (see, in particular,FIG. 19). All of these parts are described more fully below.

FIG. 2is a perspective view of the valve body and gate assembly. As shown in this figure, the gate assembly10is situated within the valve body11. The valve body11is comprised of a left and right flange11a,11band a central portion11csituated between the two flanges. The gate assembly10is comprised of a lower ball screw25, a gate mount26, and a gate28(as well as set screw27shown inFIG. 4). The gate assembly10is further comprised of a valve gate guide channel104and a valve gate guide105. In a preferred embodiment, the ball screw25is Part No. S5-016100L-305/280-D(3)B-Y/N manufactured and distributed by Heli-Tek of Muskego, Wis. The ball screw25is preferably comprised of grade 5 stainless steel and is seven inches long with a diameter of 16 mm and a 10 mm lead, left helix; the helix is preferably ground as opposed to rolled. In a preferred embodiment, the upper ball screw29is the same part as the lower ball screw25except with respect to length; the upper hail screw29is preferably 8.25 inches long. In alternate embodiments, the lead of the upper ball screw29may be different than the lead of the lower ball screw25in accordance with the requisite torque load.

This high lead angle screw is also used in the pneumatic piston actuator shown inFIG. 12. In this application, the same high lead angle ball screw is used to convert linear motion to rotary motion in order to power the driver magnet cartridge. Because the exact same ball screw is preferably used prior to the magnetic coupling as well as after the magnetic coupling, the axial motion produced by the pneumatic cylinder is replicated exactly by the motion supplied to the gate valve. This makes it easy for a technician to calibrate the proper stroke for a given gate valve, knowing that the stroke supplied from the pneumatic cylinder is identical in length to the stroke inside of the valve.

FIG. 3is a perspective view of the lower ball screw and gate assembly. The gate assembly10comprises the lower ball screw25, the bottom end of which resides within the gate mount26. The lower portion of the gate mount26is inserted into a guide channel104in the gate28.

FIG. 4is an exploded view of the lower ball screw and gate assembly. As shown in this figure, a lock pin27secures the bottom end of the lower ball screw25in the gate mount26. The bottom portion of the gate mount26slides into the recess shown in the guide channel104at the front of the gate28.

FIG. 5is an exploded view of the inner magnetic cartridge assembly. As shown in this figure, the inner magnetic cartridge assembly9is comprised of a magnet housing60, an upper tapered roller bearing20, and the inner magnetic cartridge12. It is further comprised of an inner ball nut22, spring ring23, spacer63, lower tapered roller bearing24, compression nut64and compression jam nut65. These pieces fit together, as shown, to form the inner magnetic cartridge assembly9.

FIG. 6is an exploded view of the inner magnetic cartridge. The inner magnetic cartridge12is comprised of an inner magnet carrier62around which the inner magnets61are arranged radially and spaced apart from one another so that no two magnets61are in contact with one another. The inner magnets61are situated within inner magnet channels150in the inner magnet carrier62. The inner magnet carrier62preferably comprises a set screw hole161into which a set screw30is inserted. This set screw30ensures that the ball nut22(seeFIG. 10) does not rotate.

FIG. 7is a section view of the inner magnetic cartridge assembly. This figure shows the magnet housing60, as well as the spacer63, compression nut64and compression jam nut65. The spacer63allows access to the ball nut22, and it also provides a mounting surface for the spring ring23. The spacer63also serves to lower the surface upon which the lower tapered roller bearing24is acting. The compression nut64enables tightening of all of the parts contained within the magnet housing60, and the compression jam nut65ensures that the compression nut64does not slip. A spring ring23is situated on an upper surface of the spacer63, as shown, between the spacer63and the inner magnet carrier62. A lower tapered roller bearing24is situated inside of the magnet housing60between the compression nut64and the spacer63; the lower tapered roller bearing holds the spacer63, inner ball nut22and inner magnet carrier62concentrically within the magnet housing60. An upper tapered roller bearing20is situated inside of the magnet housing60directly underneath the ceiling of the magnet housing60; its purpose is to provide a counterforce to the lower tapered roller bearing24and maintain the spacer63, inner ball nut22and inner magnet carrier62concentric within the magnet housing60. As the gate28and ball screw25move upward, force is exerted on the upper tapered roller bearing20. Similarly, as the gate28and ball screw25move downward, force is exerted on the lower tapered roller bearing24. The upper and lower tapered roller bearings20,24work together to maintain the concentricity of the parts located within the magnet housing60. Note that the angle of the upper tapered roller bearing20is opposite that of the lower tapered roller bearing24.

FIG. 8is a section view of the inner magnetic cartridge assembly with relief gap. InFIG. 7, the spring ring23is compressed; inFIG. 8, on the other hand, the spring ring23has been uncompressed, which creates a gap101between a bottom surface of the inner magnet carrier62and the spacer63, as shown. (Note that the degree of tightening of the compression nut64determines the magnitude of this gap101.) The purpose of this gap101is to allow for thermal expansion of the spacer63, inner ball nut22and inner magnet carrier62in certain high-temperature applications.

FIG. 9is a perspective view of the sealed lower section with valve body and inner magnetic cartridge assembly. This figure shows the magnet housing60and the bolts151and nuts152that secure the magnet housing60to the flange11don top of the valve body11. Note that the sealed lower section108is completely sealed to the outside environment.

FIG. 10is a section view of the sealed lower section with valve body and inner magnetic cartridge assembly shown with the valve closed. The inner magnet carrier62and inner magnets61reside inside of the magnet housing60. The outer magnets69are not shown in this figure, but as they rotate, the magnetic coupling between the outer and inner magnets69,61causes the inner magnets61(and, therefore, the inner magnet carrier62) to rotate in the same direction as the outer magnets69. The inner magnet carrier62is fixedly attached to the inner ball nut22so that the inner ball nut22also rotates with the outer magnets69. The ball nut22is locked rotationally to the inner magnet carrier62via the set screw30. The inner ball nut22converts the rotary motion of the inner magnet carrier62to a reciprocating motion. As the inner ball nut22rotates, it causes the ball screw25to move linearly up and down within the valve body11and magnet housing60. The gate28, gate mount26and ball screw25(in other words, all parts shown inFIG. 3) move together (up and down) as a single unit.

When the inner ball nut22and inner magnet carrier62rotate, the spacer63also rotates. The spacer63comprises a neck that slips into the bottom of the inner magnet carrier62(seeFIG. 8). The compression nut64puts pressure on both the inner magnet carrier62and the spacer63, which forces them to rotate together. The ball screw25moves up or down, depending on the direction of rotation of the inner magnet carrier62. The flange gasket158, which is situated between the bottom flange of the magnet housing60and the upper flange11cof the valve body, prevents fluid from escaping between the magnet housing60and the valve body11. The valve gate guide105that was shown inFIG. 1is also shown in this figure. The valve gate guide105prevents the gate28from rotating, thereby ensuring that the gate28moves only up or down within the valve body11. The valve gate guide channel104in the gale28(see alsoFIG. 2) receives the valve gate guide105, which extends inward in two parts on opposite sides of the central portion11cof the valve body.FIG. 31shows in greater detail the relationship between the valve gate guide channel104and the valve gate guide105.

FIG. 11is a section view of the sealed lower section with valve body and inner magnetic cartridge assembly shown with the valve open. The same parts are shown as inFIG. 10, except that the lower ball screw25has been moved upward by virtue of the rotation of the inner ball nut22, thereby causing the gate28to move upward as well.

FIG. 12is a perspective view of the outer magnetic assembly. As shown in this figure, the outer magnet top66(more specifically, the bottom flange of the outer magnet top) is secured to the top of a cylindrical outer magnet carrier68with cylinder head bolts45. As shown in greater detail inFIG. 13, the outer magnet top66is comprised of a cylindrical top part, a bottom flange with a protruding base, and a skirt section that joins the cylindrical top part to the bottom flange. The bottom part of the upper ball screw29is inserted into a central threaded hole in the outer magnet top66and secured with a set screw46. This set screw46ensures that the upper ball screw29does not rotate independently of the outer magnet top66.

FIG. 13is an exploded view of the outer magnetic assembly. This figure shows the outer magnetic assembly8, which rotates as a single unit. The bottom end of the ball screw29threads into the outer magnet top66and is secured with set screw46. The outer magnet top66comprises a keyway118, which receives the key41shown inFIG. 30; note that this particular part (the keyway118) is relevant only in connection with the manual actuation embodiment shown inFIGS. 26-30. The outer magnet top66is bolted to the outer magnet carrier68. A snap ring35is situated inside of the outer magnet top66(see alsoFIG. 14). To assemble the unit, the bolt44, spring washer33, retaining cap67and upper tapered roller bearing34are compressed together and inserted into the bottom of the outer magnet top66. The snap ring35is inserted into a groove in the interior of the outer magnet top66to maintain these parts in place. The bolt44fastens the outer magnetic assembly8to the sealed lower section108(seeFIG. 32). The outer magnets69are slipped inside of the outer magnet carrier68and held in place by magnetic force. Note that there are grooves inside of the outer magnet carrier68for receiving the outer magnets69(seeFIG. 19). The lower tapered roller bearing36slides into the bottom of the outer magnet carrier68and into a recess on the inside of the outer magnet carrier68(seeFIG. 14).

FIG. 14is a section view of the outer magnetic assembly. Channels153on the inside of the outer magnet carrier hold the outer magnets69inside of the outer magnet carrier68. In this figure, the channels153are longer than the magnets themselves69; this is to accommodate longer magnets if greater torque is desired. Bolt45attaches the outer magnet top66to the outer magnet carrier68. Tightening of bolt44ensures that the outer magnetic assembly8is concentric on the lower sealed section108. The bolt44is preferably secured to the sealed lower section108with some manner of thread lock. The purpose of the upper and lower tapered roller bearings34,36is to hold outer magnetic assembly8concentric to the magnet housing60. Note that the outer magnet carrier68is constraining the outer race way of the lower tapered roller bearing36, and the magnet housing60is constraining the inner raceway of the lower tapered roller bearing36. The inner raceway of the upper tapered roller bearing34is constrained by the magnet housing60, and the outer raceway of the upper tapered roller bearing is constrained by the outer magnet top66, which is concentrically and fixedly attached to the outer magnet carrier68.

FIG. 15is a perspective view of the sealed lower section with valve body and outer magnetic assembly. In this figure, the parts shown inFIGS. 9 and 12have been combined to form the assembly shown inFIG. 15. The bolt44(seeFIG. 14) is inserted into the threaded hole on the top of the magnet housing60to secure the outer magnetic assembly8to the lower sealed section108(seeFIG. 32).

FIG. 16is a perspective view of the pneumatic actuator mounting assembly. This figures shows the mount can73and retaining ring74. The purpose of the mount can73is to mount the pneumatic piston120so that it can move up and down. The mount can73is placed over the top of outer magnetic assembly8shown inFIG. 15, and then the retaining ring74is placed onto the bottom end of the mount can73. Bolts are used to fasten the retaining ring74to the bottom flange of the magnet housing60(see holes in flange inFIG. 15for receiving these bolts).

FIG. 17is an exploded view of the pneumatic actuator mounting assembly. The mount can top71is mounted via bolt holes163to the bottom of the pneumatic actuator assembly6(seeFIG. 23). The mount can divider72is an optional feature and is inserted just inside the top of the mount can73to prevent flames from coming into contact with the outer magnet assembly during fire-testing of the valve.

FIG. 18is a section view of the pneumatic actuator mounting assembly. The mount can73preferably has a shoulder117machined into it at the bottom end of the mount can73; this shoulder117holds the retaining ring74shown inFIG. 17.

FIG. 19is a top view of the magnetic coupling between the outer magnetic assembly and the inner magnetic cartridge assembly. As shown in this figure, the inner magnets61, which are held by the inner magnet carrier62, are configured so that they align radially with the outer magnets69. In this manner, there is a magnetic coupling between the outer and the inner magnets such that when the outer magnet carrier68is rotated, thereby causing the outer magnets to rotate, the inner magnets and inner magnet carrier62rotate as well.

In a preferred embodiment, the inner and outer magnets are SmCo grade to accommodate −423 to +500 degrees Fahrenheit and magnetized across the full dimension of their thickness (i.e., from outside to inside). The inner and outer magnets are preferably flat on one side and slightly curved on the other side. As shown inFIG. 19, the flat side of the inner magnets61faces inward toward the inner magnet carrier62, and the slightly curved (convex) side of the inner magnets61faces the magnet housing60. Similarly, the flat side of the outer magnets69faces the outer magnetic carrier68, and the slightly curved (concave) side of the outer magnets69faces the magnet housing60.

FIG. 20is a perspective view of the pneumatic actuator assembly. The pneumatic actuator assembly6is comprised of the pneumatic actuator37, an upper ball nut38, and a ball nut mount70. Referring toFIG. 21, the top end of the upper ball screw29(seeFIG. 12) threads into the ball nut38, which threads into the bottom of the ball nut mount70. Set screw47secures the ball nut38to the ball nut mount70so that it cannot rotate independently of the ball nut mount70. The ball nut38moves up and down but does not rotate (whereas the entire assembly shown inFIG. 12rotates); as the ball nut38moves up and down, it forces the upper ball screw29to rotate. The ball nut mount70threads into the pneumatic piston120and is held in place by set screw46(seeFIG. 21). A pneumatic shall guide (in the form of a protruding ridge)111on the inside of the pneumatic actuator37interacts with the clamp-on guide112so that the clamp-on guide rides up and down the guide111and prevents the pneumatic piston120from rotating (seeFIG. 22). Once the ball nut mount70is securely fastened to the pneumatic piston120, the piston120moves up and down within the pneumatic actuator37as air pressure is applied.

FIG. 21is an exploded view of the pneumatic actuator assembly. The pneumatic actuator37is mounted to the mount can top71(shown inFIG. 16) via bolt holes157(inFIG. 21) and163(inFIG. 16).

FIG. 22is a top section view of the pneumatic actuator rotational stop. Guide rollers155are a pair of roller bearings that ride up and down the protruding ridge111on the inside of the pneumatic actuator37, ensuring that the pneumatic piston120does not rotate. The roller bearings155are bolted to the clamp-on guide112.

FIG. 23is an exploded view of the present invention with the pneumatic actuator. All of the parts referenced in this figure are shown in an assembled state inFIG. 1. The valve body11, flange gasket158, inner magnetic cartridge assembly9, pneumatic actuator mount assembly7, and pneumatic actuator assembly6are all mounted as a single unit and not able to rotate. The pneumatic actuator assembly6contains the pneumatic piston120, which moves up and down.

FIG. 24is a section view of the present invention shown with the valve in an open position. As compared toFIG. 11, the following parts have been added: pneumatic actuator assembly6, pneumatic actuator mount assembly7, and outer magnetic assembly8.

FIG. 25is a section view of the present invention shown with the valve in a closed position. As compared toFIG. 10, the following parts have been added: pneumatic actuator assembly6, pneumatic actuator mount assembly7, and outer magnetic assembly8.

FIG. 26is a perspective view of the present invention fully assembled with a manual actuator. In lieu of the pneumatic actuator shown in the preceding figures, this embodiment incorporates a manual actuator. Specifically, the mount can73shown inFIG. 17has been replaced with the alternate mount can76shown inFIG. 28. The alternate mount can76is preferably shorter than the mount can73because it contains fewer parts.

FIG. 27is an exploded view of the present invention with the manual actuator. All parts are the same as previously described, except that the handle assembly14has been added in lieu of the pneumatic actuator assembly6, and the pneumatic actuator mount assembly7has been replaced with the manual actuator mount assembly13. As compared toFIG. 23, the pneumatic actuator assembly6, the pneumatic actuator mount assembly7, and the outer magnetic assembly8have been removed. The outer magnetic assembly15is similar to the outer magnetic assembly8ofFIG. 23, except that the upper ball screw29has been eliminated. The manual actuator mount assembly13is similar to the pneumatic actuator mount assembly7except that the top of the mount can73has been removed so that the top of the alternate mount cart76is flush with the mount can divider72(seeFIG. 17). Note that the bolt line shown at the top of the alternate mount can76is the same bolt line shown in the center of the mount can73inFIG. 17. (InFIG. 17, the mount can divider72is pushed downward within the mount can73so that the bolt holes of the mount can divider are aligned with this bolt line.) The inner magnetic cartridge assembly9, gate assembly10, flange gasket158and valve body11are the same as described previously.

FIG. 28is an exploded view of the manual actuator mount assembly. Note that the mount can top75differs from the mount can divider72in that the top surface of the mount can top75has been extended so that it covers the top edge of the alternate mount can76.

FIG. 29is a section view of the manual actuator mount assembly. This figure shows the parts shown inFIG. 28fully assembled. The alternate mount can76is secured to the mount can top75with bolts159.

FIG. 30is an exploded view of the manual actuator handle. Referring toFIG. 15, the snap ring40fits into the groove164in the outer magnet top66. Once this is snapped into place, the handle39shown inFIG. 30slips on top of the snap ring40. The diameter of the hole in the center of the handle39is the same as the outer diameter of the top part of the outer magnet top66. The snap ring40creates a shoulder on which the handle39sits. The washer42rests on the top surface of the handle39in the center of the handle, directly above the hole. The retaining bolt43threads into the hole in the top of the outer magnet top66(seeFIG. 13). The key41fits into the key way160in the center hole of the handle and also into the keyway118in the outer magnet top66(seeFIG. 13). As such, when the handle39is rotated (either manually or via a motor or other source of kinetic energy), the outer magnet top66and outer magnet carrier68rotate, thereby causing the inner magnets61and inner magnet carrier62to rotate, as described above.