Abstract:
A dual-magnet valve unit having a first master magnet ring assembly with an outer casing slidably contained within an outer housing that forms a chamber with the casing of the master magnet ring assembly and a second, slave magnet disk assembly with an outer tube and a poppet member in the form of a cone and displaceable within the inner transport fluid conduit, the inner transport fluid conduit having a valve seat contactable by the cone of the poppet member to block fluid flow through the fluid conduit in one position of the slave magnet disk assembly and displaceable from the cone to pass fluid flow through the fluid conduit in an opposite position of the slave magnet disk assembly, the master magnet ring assembly being displaced by selective supply of a motive fluid to the chamber to displace the master magnet ring assembly from one position to another, which automatically displaces the slave magnet ring assembly.

Description:
BACKGROUND OF THE INVENTION 
   This invention relates to a permanent magnet actuator mechanism of the type described in my U.S. application Ser. No. 09/802,423 filed Mar. 9, 2001. In particular, the subject matter of this application relates to a valve unit having a permanent magnet actuator mechanism for displacement of a valve member between an open position and a closed position. The dual-magnet valve unit of this invention is fluid driven and includes an outer casing or housing such that the valve unit is a compact, self-contained unit that can be incorporated in a variety of applications requiring an on-off valve. 
   In operation, a first permanent magnet member co-acts with a second permanent magnet member in a master/slave relationship. The permanent magnet members in certain embodiments are positioned with the magnet members in mutual magnetic repulsion wherein displacement of one of the permanent magnet members automatically effects opposite displacement of the other of the permanent magnet members. In displaceable embodiment the magnet members are positioned in mutual attraction wherein displacement of one of the permanent magnet members automatically effects displacement of the other of the permanent magnet members in the same direction. 
   In a basic system the use of mutually displaceable permanent magnet members enables one of the permanent magnet members to be isolated by a barrier from the other permanent magnet member. This relationship is ideal where it is desired to isolate a fluid or gas from external contamination. In such a situation the displaceable valve member may be contained in a fluid conduit and magnetically displaced by the displacement of an external permanent magnet member external to the fluid conduit. 
   SUMMARY OF THE INVENTION 
   The dual-magnet valve unit of this invention incorporates certain of the concepts described in U.S. patent application Ser. No. 709/802,423, filed Mar. 9, 2001. 
   In the referenced application there is described an embodiment of a valve with an isolated slidable spool carried on one magnet member that is displaced on displacement of another magnet member. The second magnet number is separated from the first magnet member by a wall of a conduit in which the fluid to be regulated is transported. Each of the two magnet members is preferably an assembly of permanent magnets and pole pieces configured and arranged within a containment structure to maintain a magnetic repulsion that is effected dynamically on translocation of the magnet members. 
   In the valve embodiment of the referenced application, the prime mover to effect the translocation is an electromagnetic coil system. The coil system on activation is designed to generate a magnetic field to interact with the magnetic field of the second or outer magnet member to shift the magnet member and hence automatically displace the magnetic spool member in an opposite direction. The coil system is designed to allow this process to be reversed to return the magnetic spool member to its first position. When the spool member is located in one position or the other, no energy is required in the coil system to maintain the spool member in position. 
   As noted in the referenced description, other means may be employed as the prime mover. In many industrial environments, hydraulic or pneumatic control systems are available as a means to control or regulate components of system processes. Use of a fluid medium to actuate the dual-magnet unit of this invention enables a compact, relatively inexpensive valve unit to be constructed. The unit described in this application is adapted to include springs, if desired. However, typically in a fluid actuated unit, the power necessary to displace the master magnet member is readily available, and refinements in the force profile by use of springs is generally not necessary. 
   In translocation of the magnet members, substantial momentum is generated even though the distances of displacement are relatively small. When applied as a valve unit, the valve member displaces to a closure position and contacts a valve seat. The permanent magnets and poles forming the dis placeable spool member add a substantial mass that results in a significant momentum that must be dissipated on impact on the valve seat. In certain embodiments of this invention, the valve unit is improved by a spool design in the form of a poppet plunger having an integral shock absorber to absorb the repeated impact on each closure of the valve. 
   Translocation of the magnet members is preferred in a system where the prime mover is an electromagnetic coil system. Use of a coil system to maintain and not simply switch the position of the master magnet member is preferably avoided to prevent burn-out of the coil. 
   In a fluid activated system where the pressure of a motive fluid is continuously available, the master magnet member can be maintained in one of the two positions by use of the continuously available fluid pressure. In this situation magnetic attraction of the outer magnet member and inner magnet member can be used with codirectional location of the magnet members. To optimize the magnetic attraction to achieve the force of positioning of the slave member, particularly on closure of the valve, the master magnet member must be maintained at its stop position by the drive fluid. One advantage to this arrangement is that the slave member follows this master member and avoids the impact of automatic translocation in a repulsion system. In this manner, the complex shock absorber can be omitted. 
   In addition, other features are provided including containment structures for the magnet and pole assemblies which alternately are permanently sealed by welding or sealed with static O-rings for disassembly. Additionally, novel configurations of the pole pieces are designed to facilitate assembly and improve the magnetic coupling force. 
   The improved dual-magnet valve unit is provided with a cam operated indicator to provide a visual check of the valve state to determine if the valve is open or closed. In this embodiment, there is also provided a mounting base with coupling terminals for the fluid lines of the motive fluid that actuates the displacement of the master magnet member. Furthermore, by selective design of a constricted passage for the supply of the motive fluid, the speed of actuation of the master magnet member can be controlled and tailored for different applications. 
   The improved dual-magnet valve unit of this invention utilizes low cost cylindrical parts for the housing, which forms a chamber for the encased master magnet member to be displaced in the manner of a piston by selective supply of motive fluid. The motive fluid can be liquid or gas and the unit is particularly adapted to operate with pneumatic air systems common to industrial processing operations. The dual-magnet valve unit of this invention is designed as a general application valve unit where the transported fluid must be accurately measured and/or must be free from external contamination. 
   In the embodiments described, the first and second magnet members are each an assembly of five or six magnets. It is to be understood that the number of permanent magnets, and hence pole pieces, may vary according to the application and closure force needed for a particular pressure of the transport fluid. 
   These and other features are apparent from a consideration of the detailed description of the preferred embodiments. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded view of a first embodiment of the dual-magnet valve unit of this invention. 
       FIG. 2  is a cross-sectional view of the dual-magnet valve unit of  FIG. 1 . 
       FIG. 3  is a cross-sectional view of the outer magnet ring assembly of the dual-magnet valve unit of  FIG. 2 . 
       FIG. 3A  is an end view of a ring pole in the outer magnet ring assembly of  FIG. 3 . 
       FIG. 4  is a cross-sectional view of the transport fluid conduit assembly and inner magnet disk assembly of the dual-magnet valve unit of  FIG. 2 . 
       FIG. 4A  is an enlarged view of part of the magnetic disk assembly of  FIG. 4 . 
       FIG. 5  is a perspective view of the plunger stop element of the dual-magnet valve unit of  FIG. 2 . 
       FIG. 6  is a perspective view of the poppet member of the dual-magnet valve unit of  FIG. 2 . 
       FIG. 7  is a perspective view of a second embodiment of the dual-magnet valve unit. 
       FIG. 8  is a cross-sectional view of the dual-magnet valve unit of  FIG. 7 . 
       FIG. 9  is a cross-sectioned view of a third embodiment of the dual-magnet valve unit. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The fluid driven, dual-magnet valve unit of this invention, is designated generally by the reference numeral  10 . A first basic embodiment of the dual-magnet valve unit  10  is described with reference to  FIGS. 1–4  and is identified by the reference numeral  12 . A second mountable embodiment of the dual-magnet valve unit  10  is described with reference to  FIGS. 7 and 8  and is identified by the numeral  14 . A third embodiment of the dual-magnet valve unit  10  that utilizes magnetic attraction, and is described with reference to  FIG. 9  and is identified by the reference numeral  250 . 
   Referring to the exploded view of  FIG. 1 , the basic bistable dual-magnet valve unit  12  has a containment housing  16  comprising an outer casing  18  with a removable end cap  20 . The outer casing  18  and end cap  20  contain a displaceable first magnet member  22  comprising an outer magnet ring assembly  24  and a displaceable second magnet member  26  comprising an inner magnet disk assembly  28 . 
   Isolating the annular outer magnet ring assembly  24  from the cylindrical inner magnet disk assembly  28  is a transport fluid conduit assembly  30 . The transport fluid conduit assembly  30  comprises a high pressure cylindrical tube  32  having first and second specialized end fittings  34  and  36 , which provide for connection of conventional fittings of a fluid line (not shown) for the controlled fluid transported through the dual magnet actuator unit. It is to be understood that the controlled transport fluid is the liquid or gas that is regulated by the bistable valve unit of this invention and differs from the drive fluid which is a liquid or gas that is employed as the pressure medium that comprises the external prime mover for actuating the valve unit. 
   The transport fluid conduit assembly  30  contains the second inner magnet disk assembly  28  and isolates the transport fluid from the first outer magnet ring assembly  24  and prevents the transport fluid from contact with or contamination by the drive fluid. For example, the pressurized drive fluid comprises air in a pneumatic system that actuates the valve unit for a liquid in a processing system where the liquid flow is required to start and stop. As noted in the referenced patent application, the hermetically isolated inner magnet disk assembly acting as a valve poppet does not affect the volume of the transport fluid unlike a typical globe valve or gate valve where the valve stem enters into and withdraws from the transport fluid during closing and opening of such valves. 
   Referring in addition to  FIG. 2 , the cross-sectional view of the basic dual-magnet valve unit  12  illustrates the assembled components which are substantially symmetrical about a common axis. The outer casing  18 , however, has side entry ports  38  and  40  for connection of conventional fittings (not shown) for the drive fluid supply lines  42  and  44 . 
   The supply of the pressurized drive fluid is regulated by a conventional control system for selective delivery of a pressurized drive fluid to one of the two entry ports  38  and  40  for displacement of the outer magnet ring assembly  24  in an annular chamber  46 . The annular chamber is defined by the inner wall  48  of the outer casing  18 , a unitary containment end  50  of the outer casing  18 , the removable casing end cap  20  and the cylindrical tube  32  of the conduit assembly  30 . 
   The annular chamber  46  is effectively divided into two compartments  52  and  54  by an O-ring seal  56  that seats in a groove  58  in a raised perimeter seal seat  60  in a casing  62  of the outer magnet ring assembly  24 . The entry ports  38  and  40  communicate with the compartments  52  and  54 , respectively, by a constricted passage  63 , which is sized to control the speed of actuation. Other valving in the drive fluid control system may provide an alternate means of controlling the actuation as desired. 
   The outer magnet ring assembly  24  functions in the manner of a floating piston between end stops  64  and  66 . The end stops  64  and  66  limit the displacement of the outer magnet ring assembly  24  and are formed by the inside wall  68  of the containment end  50  of the outer casing  18  and the inside wall  70  of the end cap  20 . 
   In operation, when the pressurized drive fluid is admitted through port  40  with pressure in port  38  relieved, the outer magnet ring assembly  24  is driven to the inside wall  68  of the containment end  50  of the outer casing  18  as shown in  FIG. 2 . Notably, the inner magnet disk assembly  28  is automatically driven by magnetic repulsion to its displacement limit in the opposite direction. When the pressurized drive fluid is admitted through port  38  with pressure in port  40  relieved, the outer magnet ring assembly  24  is driven to the opposite stop  66  against the inside wall  70  of the end cap  20 . Again, by magnetic repulsion the inner magnet disk assembly  28  is automatically displaced to its opposite displacement limit. 
   The removable end cap  20  permits installation of the outer magnet ring assembly  24  and may be press-fit to the outer casing  18  with an O-ring seal  72  as shown, or secured by threading, or alternately by soldering, brazing or welding for a permanent assembly. 
   Referring also to  FIG. 3 , the annular casing  62  of the outer magnet ring assembly  24  has a first end  74  with a circular opening  76  sufficiently large to slidably engage the high pressure cylindrical tube  32  of the transport fluid conduit assembly  30  and sufficiently small to seat a first ring pole  78   a  of the six alternating ring poles  78  and five ring magnets  80  of the magnet subassembly  82  of the outer magnet ring assembly  24 . The opening  76  has an internal groove  84  to seat an O-ring seal  86  for sealing the magnet subassembly  82  from the drive fluid contained in the annular chamber  46 . 
   It is to be understood that the O-ring seals used in the bistable dual-magnet valve unit  10  may be replaced with other seals or packings depending on the application of the unit. Also, as noted certain seals may be eliminated where components are permanently joined by soldering, brazing or welding. 
   The opposite end  88  of the casing  62  of the outer magnet ring assembly  24  has a circular opening  90  sized to permit installation of the ring poles  78  and ring magnets  80 . The magnet subassembly  82  is retained by an annular end cap  92  and retainer clip  94  that seats in a groove  96  in the opening  90 . A spacer  98  between the end cap  92  and the end ring pole  78   b  is sized to clamp together the ring poles  78  and ring magnets  80  of the subassembly  82  on assembly. 
   To facilitate assembly and improve the magnetic flux directed at the inner magnet disk assembly  28 , the ring poles  78  have a slightly smaller inside diameter than the ring magnets  80  and include radial ears  99  as shown in  FIG. 3A . 
   Referring also to  FIG. 4 , the transport fluid conduit assembly  30  and contained inner magnet disk assembly  28  are shown in cross section without the other components for clarity. The specialized end fittings  34  and  36  at opposite ends of the high pressure tube  32  have an external hex head portion  100  for gripping with a wrench when connecting the carrier fluid line when installing the dual-magnet valve unit  10  in a system. This portion of the end fittings  34  and  36  can be tailored for the type of connector required for the carrier fluid line. 
   The end fittings  34  and  36  have differing internal portions  102  and  104  to accommodate the different functional ends  106  and  108  of the inner magnet disk assembly  28 . 
   The end fitting  34  has an internal fluid passage  110  that has a constricted internal port  112  to the internal chamber  114  of the fluid transport conduit assembly  30 . The blunt internal end face  116  forms a stop  117  for a corresponding plunger stop element  118 . As shown in the perspective view of  FIG. 5 , the plunger stop element  118  is in the form of a truncated cylindrical disk with chordal side faces  120 , and a gap  122  that forms a fluid by-pass  121 . Curved side faces  123  provide a slide guide for the displacement in the cylindrical tube  32  of the conduit assembly  30 . The plunger stop element  118  is secured on a post  119  of an end cap  124  that is connected to a cylindrical plunger casing  126  for containing the inner magnet subassembly  128  of the inner magnet disk assembly  28 . The assembled inner magnet disk assembly  28  forms a poppet plunger. 
   The magnet subassembly  128  has a spacer  130  at the end of an alternating series of disk poles  132  and disk magnets  134 . The plunger casing  126  is spaced from the high pressure tube  32  of the conduit assembly  30  to provide transport for fluid flow and this creates part of the gap between the outer magnet subassembly  82  and the inner magnet subassembly  128 . The series of six disk poles  132  and five disk magnet  134  are arranged for magnetic repulsion with the ring poles  78  and ring magnets  80  of the outer magnet subassembly  82  as taught in the referenced patent application. 
   The end fitting  36  has the internal portion  104  formed with an internal passage  138  having a constricted port  140  with a flared or conical valve seat  142 . The inner magnet disk assembly  28  has a poppet member  144  with a specially formed cone  146 , shown in the perspective view of  FIG. 6 . The cone  146  preferably has the cross-sectional configuration of a gothic arch for strength and durability. The cone  146  provides the complimentary seating member for the valve seat  142  when the inner magnet disk assembly  28  operates as a poppet plunger and is displaced by magnetic force against the end fitting  36 . This force is maintained by the mutual magnetic repulsive forces and the cone  146  seats forcefully on the valve seat  142  to seal the internal passage  138 . 
   The plunger casing  126  is constructed similar to a shell casing with a unitary base  148  recessed from an end portion  150  that provides a socket for a shock absorber  151  as shown in greater detail in the enlarged view of  FIG. 4A . The shock absorber  151  has a shock absorber cup  152  with a lip  154  having a seating flange  156  and locking ridge  158  to retain the cup  152  with the cup bottom  160  displaced from the base  148  of the plunger casing  126 . Similarly, the poppet member  144  has a base  162  with an enlarged end  164  that seats in the cup  152  with a substantially square flange  166  displaced from the seating flange  156  of the lip  154  of the cup  152 . The rounded corners  155  of the flange  166  of the poppet member  144  and the curved side faces  123  of the disk-shaped plunger stop element  118  are sized to slidably engage the inside wall  157  of the high pressure tube  32 . 
   Since the force required to seal the internal passage  138  may be considerable, depending on the transport fluid pressure, the dynamics of displacing the inner magnet disk assembly  28  or poppet plunger results in a substantial momentum that must be dissipated without damage to the cone  146  of the poppet member  144 . The flexure of the cup  152  to the plunger case base  148 , which acts as a stop, and the contact of the poppet member flange  166  against the cup seating flange  156 , which acts as a cushioned stop, absorb the shock of valve closure. 
   The use of the shock absorber  151  between the poppet member  144  of the plunger or inner magnet disk assembly  28  to cushion the impact of the cone  146  with the valve seat  142  of the conduit assembly  30  substantially improves the cycle life of the magnetic valve unit  10 . It is to be understood that a combination shock absorber and poppet member of different configuration may be designed according to the particular specifications of the environment of use including flow rates, fluid pressure, fluid consistency, and other parameters affecting design. This design selection also applies to the materials used in the valve unit where components are in contact with caustic or acidic transport fluids. For most applications stainless steel pressure tubes and fittings are preferred with the poppet member  144  fabricated of a polyether-ether keytone (PEEK™) and the shock absorber cup  152  fabricated from a polytetrafluoroethylene compound (TEFLON™). Housings, casings and other parts not in contact with the transport fluids may be fabricated from aluminum or other high-strength, light-weight material. 
   Referring now to the perspective view of  FIG. 7 , the bistable dual-magnet valve unit  10  shown therein is an alternate mountable embodiment  14 . In  FIG. 7 , and in the cross-sectional view of  FIG. 8 , the elements and components of the valve unit  14  are identical to those of  FIGS. 1–6  and are each identified by the same reference numeral except where modified and renumbered as set forth herein. 
   In  FIGS. 7 and 8 , a modified outer casing  170  of the valve unit  14  seats in a cradle mount  172 . The outer casing  170 , as shown in  FIG. 8 , has circumferential grooves  174  at each end which are engageable by a semi-circular angular ridge  176  on a raised end  178  of the cradle mount  172  and by a similar angular ridge  180  on an end plate  182 . The end plate  182  is coupled to the cradle mount  172  by screws  184  (shown in phantom) to clamp the casing  170  to the cradle mount  172 . 
   The cradle mount  172  has a curved bed  186  that is complimentary to the circular casing  170 . When the end plate  182  is secured to the cradle mount, the angled ridges  176  and  180  wedge the circular casing  170  firmly to the curved bed  186 . The cradle mount is provided with two recessed mounting holes  188  to attach the coupled valve unit  14  to a desired mounting surface. 
   A location pin  190  projecting from the bed  186  of the cradle mount  172  is positioned into a complimentary locator bore  192  in the casing  170  for properly orienting the outer casing  170  on the bed  186 . In this manner, the side entry ports  194  and  196  in the casing  170  are aligned with connecting ports  198  and  200  in the bed  186  of the cradle mount  172 . The ports  198  and  200  have seals  202  and communicate with passages  203  and  204  that connect with terminal ports  206  (shown in dotted line). The drive fluid lines thereby connect to the terminal ports at the side of the cradle mount  170 . Because of the relocation of the side entry ports  194  and  196  to accommodate the mounting holes and locator pin on the bed, side entry ports  194  and  196  communicate with an annular chamber  212  that is effectively divided into two compartments  214  and  216  by two O-rings  220  on a modified containment housing  222  of the outer magnet ring assembly  24 . 
   The modified dual-magnet valve unit  14  of  FIGS. 7 and 8  includes a state indicator  224  for indicating whether the valve unit  14  is in an open or closed state. The indicator  224  is constructed with a shell  226  seated in the modified outer casing  170 . The shell  226  has a transparent lens  228  for viewing an indicator  230  projecting from a pivotal cam ring  232 . The cam ring has a cam member  234  that engages a central groove  236  in the modified containment housing  222  of the outer magnet ring assembly  24 . Linear displacements of the outer magnet ring assembly  24  translate to an 90° angular displacement of the cam ring  232  and indicator  230 . The indicator  230  has a suitable marking such as an arrow (not shown) to indicate the state of the valve unit  14 . It is to be understood that this feature can be included on the basic unit  12  without the cradle mount by suitable modification. 
   Referring to the cross-sectional view of  FIG. 9 , an alternate embodiment of the dual-magnet unit  10  is shown and identified by the reference numeral  250 . The dual-magnet unit  250  utilizes magnetic attraction between the outer first magnet member  252  and a second inner magnet member  254 . Although similar in construction to the bistable dual-magnet units  12  and  14  of the previously described embodiments, the dual-magnet unit of  FIG. 9  is not inherently bistable, requiring the continuous application of the drive fluid to maintain the full displacement of first outer magnet member for transfer of the magnetic attraction force to the inner magnet member  254 . The elements of the dual-magnet unit  250  are substantially the same as the elements of the prior embodiment and common reference numerals are used except for significantly modified structures. Notably, the permanent ring magnets  80  and disk magnets  134  are arranged with their polarity for mutual attraction, as represented by the composition arrows, as contrasted with the mutual repulsion of the units  12  and  14  shown in  FIGS. 2 and 8 . 
   As shown in  FIG. 9 , a modified outer casing  256  and connected end cap  250  house the outer first magnet member  252 , the second inner magnet member  254  and the transport fluid conduit assembly  30 . The outer first magnet member  252  is in the form of the annular outer magnet ring assembly  24  of  FIG. 2  with a casing  62  having a raised seal seat  60  with an O-ring seal  56  to divide the annular chamber  46  into two compartments  52  and  54 . Each compartment has an entry port,  38  and  40  with a constructed passage  63  to controal the speed of actuation as previously described. 
   The outer magnet ring assembly  24  functions as a floating piston between end stops  64  and  66  as noted. However, to maintain the outer magnet ring assembly  24  against a particular end stop, the pressurized drive fluid initiating the displacement to the stop must be maintained. The inner magnet disk assembly  28 , with its shorter displacement distance, follows the outer magnet ring assembly  24  and is urged against one of the end fittings  34  and  36 . For simplicity, end fittings  36  is welded to the high pressure tube  32  of the transport fluid conduit assembly  30 . The opposite end fitting  34  retains the O-ring assembly as previously described to enable disassembly, if necessary. As noted, many of the O-ring, press fit or shrink fit connections can be replaced with premanent assemblies using soldering, brazing or welding. 
   The end fitting  36  has the internal passage  138  with the flared or conical valve seat  142  axially positioned for contact by the poppet member  144 . The poppet member  144  is in the form of a simplified cone  260  which seats in the end socket  262  of the plunger casing  126 . Since the inner magnet disk assembly  28  follows displacements of the outer magnet ring assembly  24  and is not translocated in the opposite direction as in the previously described embodiments, the velocity of displacement can be controlled and the shock absorber for the cone  260  is not required. 
   The inner magnet disk assembly  28  includes the plunger stop element  118 ; as previously described, which contacts the stop  117  formed by the end face  116  of the end fitting  34 . 
   The pressurized drive fluid is selectively admitted through ports  38  and  40  as previously described. However, while in the previous embodiments the pressure may be pulsed to effect the displacement and then relieved, in the embodiment of  FIG. 9 , the pressure must be maintained in the selected compartment to maintain the outer magnet ring assembly  24  against one of the stops  64  and  66  to optomize the force of attraction with the inner magnet disk assembly  30 . 
   While, in the foregoing, embodiments of the present invention have been set forth in considerable detail for the purposes of making a complete disclosure of the invention, it may be apparent to those of skill in the art that numerous changes may be made in such detail without departing from the spirit and principles of the invention.