Abstract:
Embodiments of the present invention are directed to methods and devices for conveying or containing fluids under pressure in which seals are provided with a defined path to vent fluid in the event of a seal failure.

Description:
CROSS REFERENCE RELATED APPLICATION 
       [0001]    This application is a divisional of U.S. patent application Ser. No. 11/573,742, filed on Aug. 22, 2007, which is a continuation of PCT/US2005/029205, filed Aug. 17, 2005 and U.S. Patent Application Ser. No. 60/602,376, filed Aug. 18, 2004. The entire contents of these applications are incorporated herein by reference 
     
    
     STATEMENT REGARDING FEDERALLY FUNDED RESEARCH AND DEVELOPMENT 
       [0002]    N/A 
       FIELD OF INVENTION 
       [0003]    The present invention relates to the field of fluid handling devices. 
       BACKGROUND OF THE INVENTION 
       [0004]    The present invention is directed to devices for handling fluids under pressure. For example, without limitation, embodiments of the present invention have application for pumps and valves that produce or control fluids under pressure. Devices for handling high pressures are built with parts and components with closely controlled tolerances. Such parts and components are also expensive to manufacture. It is desirable to be able to design components and parts which exhibit wear such that the worn parts and components can be replaced. And, it is desirable to reuse parts and components with closely controlled tolerances. 
         [0005]    Unfortunately, worn parts and components may cease functioning prior to replacement. The function of many parts and components of fluid handling devices is to contain fluid under pressure. For example, the failure of seals in a valve or pump may release fluid into sections of the device which can not withstand the pressure and/or pulsation of the fluid. The parts and components to which a pressurized fluid is inappropriately applied may work free or change alignment from other components and parts. Specialized pumps for performing chromatography often have sapphire pistons. Mis-aligned pistons may gouge precision surfaces of such pumps. The pistons may be scratched or otherwise damaged. Parts and components to which inappropriate pressure is applied may permanently deform. 
         [0006]    In the field of chromatography, there is an interest in operating at elevated pressures. Conventional pressures for performing high performance liquid chromatography are up to approximately 3,000 pounds per square inch (psi). Pressures for performing ultra performance liquid chromatography may reach 15,000 to 20,000 psi. With greater pressure, the potential for seal failure is greater and the potential for damage is greater. 
         [0007]    It would be desirable to have parts and components of fluid handling devices convey fluids to the exterior of the device in a manner that does not allow inappropriate pressure to be applied to parts and components. 
       SUMMARY OF THE INVENTION 
       [0008]    Embodiments of the present invention are directed to devices and methods for directing fluids away from surfaces with closely controlled tolerances to prevent damage in the event of a leak. One embodiment of the present invention is directed to a device for producing or conveying fluids under pressure. The device comprises a housing having a housing exterior, cap abutment surface, a chamber and a bore opening. The chamber is for containing fluid under pressure. The cap abutment surface is an area of the housing apart from the exterior that surrounds the bore opening for receiving a cap. The bore opening extends from the cap abutment surface to the chamber. The bore opening has a sealing surface and at least one housing seal compression surface. A seal is held in the bore opening. The seal has a seal opening and a housing engagement surface, said seal opening for receiving a shaft extending axially there-through. The seal sealing engaging said housing engagement surface against said sealing surface upon axial compression of the seal against said seal compression surface. The device further comprises a shaft having a shaft axis and mounted in the seal opening of the seal. The shaft is for rotation about the shaft axis or movement along the shaft axis. The device further comprises a cap having a cap exterior, housing abutment surface, a cap opening and a cap seal compression surface. The cap is affixed to the housing with the housing abutment surface engaging the cap abutment surface. The shaft extends through the cap opening and the cap seal compression surface is pressed against the seal compelling the seal against the seal compression surface to sealing engage the housing engagement surface against the sealing surface. The device further comprises a passage means for receiving and conveying fluid from said housing engagement surface to at least one of the cap exterior or the housing exterior and away from the cap is abutment surface and the housing abutment surface. 
         [0009]    Typically, the cap abutment surface and housing abutment surface influence the relationship of other components and parts. For example, the misalignment of the cap with respect to the housing will cause a corresponding misalignment of the shaft in the seal opening, cap opening and the bore opening. This misalignment can lead to undue expensive wear and damage to the these components. The passage means of the present invention directs fluids which are under pressure, away from this sensitive area. 
         [0010]    The passage means of one embodiment of the present invention is a channel in at least one of the housing or cap. A preferred passage means is incorporated in the seal. Preferably, the seal has a flexible body section and a seal compression pad. The body section is for engaging the housing engagement surface. The seal compression pad has less flexibility than the flexible body section to compress the flexible section against said seal compression surface. Preferably, the seal compression pad has a cap engaging surface. A preferred passage means is at least one channel in the cap engaging surface. The channel preferably extends radially across the cap engaging surface from the cap opening. 
         [0011]    In the alternative, one embodiment of the present invention has at least one channel in said seal compression surface of the cap. 
         [0012]    The device of the present inventions may comprise a pump, wherein the housing is a pump housing, or a valve, wherein the housing is a valve housing. In pump applications, the shaft may rotate or move in or out of the chamber to compel fluid movement. For example, without limitation, the shaft may comprise a reciprocating piston within the chamber. 
         [0013]    The device of the present invention has particular utility in pump and valve applications with fluids under high pressure and ultra high pressure. 
         [0014]    A further embodiment of the present invention comprises a method of producing or conveying fluids under pressure. The method comprising the steps of providing a device having a housing having a housing exterior, cap abutment surface, a chamber and a bore opening. The chamber is for containing a fluid under pressure. The cap abutment surface is a area of the housing apart from the exterior surrounding the bore opening for receiving a cap. The bore opening extending from cap abutment area to the chamber. The bore opening has a sealing surface and at least one housing seal compression surface. 
         [0015]    The device further comprises a seal held in the bore opening. The seal has a seal opening and a housing engagement surface. The seal opening is for receiving a shaft extending axially therethrough. The seal sealing engages the housing engagement surface against said sealing surface upon axial compression of the seal against said seal compression surface. A shaft, having a shaft axis, is mounted in the seal opening of the seal for rotation about said shaft axis or movement along a shaft axis. 
         [0016]    A cap having a cap exterior, housing abutment surface, a cap opening and a cap seal compression surface, is affixed to the housing with the housing abutment surface engaging the cap abutment surface. The shaft extends through the cap opening. The cap seal compression surface is pressed against the seal compelling the seal against the seal compression surface to sealing engage the housing engagement surface against the sealing surface. The device provides passage means from the housing engagement surface to at least one of the cap exterior or the housing exterior and removed from the cap abutment surface and the housing abutment surface. 
         [0017]    The method further comprises the step of operating such device such that fluid from the housing engagement surface is directed to the exterior of the cap or the exterior of the housing and away from the cap abutment surface and the housing abutment surface. 
         [0018]    The passage means may take several forms. For example, the passage means may comprise a channel in at least one of the housing or cap. Or, the passage means may be incorporated in the seal. A preferred seal has a flexible section and a seal compression pad. The flexible section is for engaging the housing engagement surface. The seal compression pad has less flexibility than the flexible section to compress said flexible section against said seal compression surface. A channel is provided in the seal compression pad to direct fluids to the exterior of the housing or cap. Where the housing is a pump or valve housing, embodiments of the present invention prevent major damage in the event seals leak. 
         [0019]    A further embodiment of the present invention is directed to a seal for use in a device for producing or conveying fluids under pressure. The seal comprises a seal body constructed and arranged to be received in a bore opening of a housing. The housing has a housing exterior, cap abutment surface, a chamber and a bore opening. The chamber is for containing fluid under pressure. The bore opening extends from the cap abutment surface to the chamber. The bore opening also has a sealing surface and at least one housing seal compression surface. The cap abutment surface surrounds the bore opening for receiving a cap. The seal body has a seal opening for receiving a shaft extending axially there-through. The shaft has a shaft axis and is constructed and arranged to be mounted in the seal opening of the seal for rotation about the shaft axis or movement along a shaft axis. The seal body has a housing engagement surface, a seal pad and a seal surface. The housing engagement surface is constructed and arranged for engaging the housing seal compression surface. The seal surface, upon axial compression of the seal body against the seal compression surface, sealing engages the sealing surface of the bore opening. The seal further comprises a cap pad affixed to the seal body. The cap pad has a cap pad opening constructed and arranged to cooperate with the seal body opening. The cap pad has a rigidity greater than the rigidity of the seal body to convey compressive force to the seal body. The cap pad has a cap engaging surface for receiving a cap seal compression surface of a cap. The cap has a cap exterior, housing abutment surface, a cap opening and a cap seal compression surface. The cap is constructed and arranged to be affixed to the housing with the housing abutment surface engaging the cap abutment surface and the shaft extending through said cap opening. The cap seal compression surface is pressed against the cap engaging surface compelling the seal surface to engage said housing engagement surface against the sealing surface. The seal further comprises passage means for receiving and conveying fluid from the housing engagement surface to at least one of the cap exterior or the housing exterior and away from said cap abutment surface and said housing abutment surface. 
         [0020]    A preferred passage means is at least one channel in the cap engaging surface. 
         [0021]    Embodiments of the present invention provide a defined path for fluids which leak past seal surfaces and prevent the build up of pressure between parts of pumps and valve assemblies. This build up of pressure can result is miss-aligned parts and components which parts and components may be subject to stresses which they can not withstand or result in wear. 
         [0022]    These and other features and advantages will be apparent to those skilled in the art upon viewing the drawings and the detailed description that follow. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  depicts, in cross section, a device incorporating features of the present invention. 
           [0024]      FIG. 2  depicts, in cross section, the pump assembly of a device depicted in  FIG. 1 . 
           [0025]      FIG. 3  depicts, in cross section, a seal incorporating features of the present invention. 
           [0026]      FIG. 4  depicts an angled view of the seal depicted in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    Embodiments of the present invention will now be described with respect to the Figures with the understanding that the embodiments described are preferred embodiments. For example, without limitation, the following discussion will describe a pump assembly with the understanding that the invention applies to valves and other fittings as well. 
         [0028]    Turning now to  FIG. 1 , a device, in the form of a pump, generally designated by the numeral  11  is depicted. The device  11  has a housing  13 , a seal  15 , a cap  17 , shaft  19  and passage means  21   a,    21   b,  and  21   c  as best seen in  FIG. 2 . Returning now to  FIG. 1 , device  11 , as a pump, produces fluids under pressure. However, features of device  11  may be modified such that the device could direct fluids to different fluid paths in the nature of a valve or fitting. 
         [0029]    The housing  13  is part of a pump assembly  25  having a motor  27  and spindle mechanism  29 . Those skilled in the art will recognize that housing  13  could be described as a housing for a valve [not shown] in which the spindle mechanism  29  would normally comprise suitable gearing and the like. As depicted, spindle mechanism  29  is mechanically linked to a shaft  19 . 
         [0030]    Housing  13  is depicted in greater detail in  FIG. 2 . Housing  13  has a housing exterior  31 , a cap abutment surface  33 , a chamber  35  and a bore opening  37 . The cap abutment surface  33  comprises an area of the housing  13 , separate from the exterior  31 , surrounding the bore opening  37 , for receiving a cap  17 . The housing  13  has a cap recess  39  to align the cap  17 . 
         [0031]    Chamber  35  is for containing fluid under pressure. As a pump, the shaft  19  moves in and out of the chamber  35  causing fluids to move. As a valve, it would be more common that the shaft  19  rotate and turn a rotor [not shown] fitted to a stator [not shown]. As depicted, chamber  35  has an inlet  43  and an outlet  41  for receiving and discharging fluids. 
         [0032]    Bore opening  37  extends from the cap abutment surface  33  to the chamber  35 . Bore opening  37  may be substantially contiguous with chamber  35 . Bore opening  37  has a sealing surface  45  and at least one housing seal compression surface  47 . Sealing surface  45  is for creating a seal between the housing  13  and seal  15 . Housing seal compression surface  47  is for creating a compressive force on the seal  15  which will compel the seal  15  against the sealing surface  45 . 
         [0033]    Seal  15  is held in the bore opening  37 . As best seen in  FIGS. 3 and 4 , the seal  15  has a seal opening  49  and a housing engagement surface  51 . The seal opening  49  receives shaft  19  extending axially there-through. The surface of the seal opening  49  sealing engages the shaft to prevent fluid from escaping the chamber  35 . The housing engagement surface  51  sealing engages the sealing surface  45  of the bore opening  37  upon axial compression of the seal  15  against the housing seal compression surface  47 . 
         [0034]    Seal  15  has a seal body  55  and a seal compression pad  57 . The seal body  55  is a flexible section that engages the sealing surface  45  of the bore opening  37 . The seal body  55  has a canted coil spring  59 . Canted coiled spring  59  creates radial force directed inward and outward upon compression of the seal  15  against the housing seal compression surface  47 . This radial force facilitates the sealing engagement of the housing engagement surface  51  with the sealing surface  45  of the housing  13 . However, seal  15 , holding pressure up to 15,000 psi, may fail. Upon failure, the fluid leaks to areas of the pump until an outlet is reached, or if confronted with a sealed area, the fluids will build up pressure. However, the pressure may build in areas of the device  11  which are pressure sensitive. 
         [0035]    Seal compression pad  57  has less flexibility than seal body  55  to compress the seal body  55  against the housing seal compression surface  47 . The seal compression pad  57  is made of plastic, such as, by way example, without limitation, polyethylene ether ketone, (PEEK). The seal body  55  is made of rubber or rubber-like materials. The seal compression pad  57  has a cap engaging surface  61  for engaging the cap  17 . It will be recognized by those skilled in the art, that the seal compression pad  57  may represent a area of a seal body that is more rigid than sections of the seal body performing sealing functions. That is, the seal cap  57  may be integral with the seal body  55 . 
         [0036]    Returning now to  FIG. 2 , shaft  19  has a shaft axis  63  extending lengthwise along the shaft. The shaft  19  is generally cylindrical and shaft  19  and seal  15  are constructed and arranged such that shaft  19  fits seal opening  49 . Shaft  19  is mounted in the seal opening  49  of the seal  15  for rotation about said shaft axis  63  or reciprocating movement along a shaft axis  63 . 
         [0037]    Cap  17  has a cap exterior  67 , housing abutment surface  69 , a cap opening  71  and a cap seal compression surface  73 . The cap exterior  67  is that part of the cap  17  other than housing abutment surface  69 , cap opening  71  and cap seal compression surface  73 . Cap  17  is affixed to the housing  13  with the housing abutment surface  69  engaging the cap abutment surface  33 . The relationship of the housing  13  to the cap  17  is important. The cap  17  is to secured to other components as depicted in  FIG. 1 . Misalignment of the cap  17  with the housing  13  may cause extreme wear of moving components and may alter the shape of components not designed for pressure. 
         [0038]    Returning now to  FIG. 2 , shaft  19  extends through the cap opening  71 . Cap seal compression surface  73  is pressed against the seal  15  at the cap engaging surface  61  of the seal compression pad  57 . The seal  15  is compelled against the seal compression surface  47  by the seal compression pad  57  to sealing engage the housing engagement surface  51  against the sealing surface  45 . 
         [0039]    Device  11  has passage means  21  for receiving and conveying fluid from the housing engagement surface  51  to at least one of the cap exterior  67  or the housing exterior  31  and away from the cap abutment surface  33  and the housing abutment surface  69 . Passage means  21  may take several forms. For example, without limitation, one embodiment of passage means  21  is at least one channel  21   b  in a cap engaging surface  61  of the seal  15 , and in particular, the seal compression pad  57  as best seen in  FIG. 4 . 
         [0040]    In the alternative, channels [not shown] can be provided in the cap seal compression surface  72  of the cap  17 . As a further alternative, returning again to  FIG. 2 , passage means  21  is a channel  21   b  in the housing  13 . As a further alternative, a channel  21   c  is provided in the cap  17 . 
         [0041]    Embodiments of the present device prevent critical wear and damage to parts of a valve and/or pump or other fluid containing device in the event of a seal failure. These advantages and features may be realized with a seal  15  having a seal body  55  having channels  21   a  in a cap engaging surface  61  for pumps, valves and fittings. 
         [0042]    Embodiments of the present invention directed to a method are discussed herein with respect to the manner of operation. One method of the present invention is directed to a method of producing or conveying fluids under pressure. The method comprises the steps of providing a device  11  having a housing  13  having a housing exterior  31 , cap abutment surface  33 , a chamber  35  and a bore opening  37 . The chamber  35  is for containing fluid under pressure. The cap abutment surface  33  comprising an area separate from the housing exterior  31  and surrounding the bore opening  37  for receiving a cap  17 . The bore opening  37  extends from the cap abutment surface  33  to the chamber  35  and has a sealing surface  45  and at least one housing seal compression surface  47 . The device further comprises a seal  15  held in the bore opening  37 . The seal  15  has a seal opening  49  and a housing engagement surface  51 . The seal opening  49  receives a shaft  19  extending axially therethrough. The seal  15  sealing engages the housing engagement surface  51  against the sealing surface  45  upon axial compression of the seal  15  against the seal compression surface  47 . The device  11  further comprises a shaft  19  having a shaft axis  63  and mounted in the seal opening  49  of the seal  15  for rotation about the shaft axis  63  or movement along a shaft axis  63 , for example a reciprocating inward and outward movement. The device  11  further has a cap  17  having a cap exterior  67 , housing abutment surface  69 , a cap opening  71  and a cap seal compression surface  73 . The cap  17  is affixed to the housing  13  with the housing abutment surface  69  engaging the cap abutment surface  33  and the shaft  19  extending through the cap opening  71 . The cap seal compression surface  73  presses against the seal  15  compelling the seal  15  against the seal compression surface  47  to sealing engage the housing engagement surface  51  against said sealing surface  45 . 
         [0043]    The device  11  further has passage means  21   a,    21   b  or  21   c  from the housing engagement surface  51  to at least one of the cap exterior  67  or the housing exterior  31  and removed from the cap abutment surface  33  and the housing abutment surface  69 . 
         [0044]    The method further comprises the step of operating the device  11  such that fluid from the housing engagement surface  51  is directed to the cap exterior  67  or the housing exterior  31  and away from the cap abutment surface  33  and the housing abutment surface  69 . 
         [0045]    The method of the present invention can be performed by providing a device  11  or providing a seal  15  in a device  11 . One further embodiment of the present invention is directed to such a seal  15 . The seal  15  comprises a seal body  55  constructed and arranged to be received in a bore opening  37  of a housing  13 . The bore opening  37  and the housing are as described previously. The seal body  55  has a seal opening  49  for receiving a shaft  19  extending axially there-through. The shaft  19  is a previously described. The seal body  55  has a housing engagement surface  51  for engaging the housing seal compression surface  47  of the housing  13  upon axial compression of the seal body  55 . The seal  15  further comprises a cap pad  57  affixed to the seal body  55  or integral with the seal body  55 . The cap pad  57  has the seal opening  49  extending therethrough for receiving the shaft  19 . The cap pad  57  has a rigidity greater than the rigidity of said seal body  55  to convey compressive force to the seal body  55 . The cap pad  57  has a cap engaging surface  61  for receiving a cap seal compression surface  73  of a cap  17 . The features of the cap  17  are as previously described. And, such seal  15  comprising passage means  21   a  for receiving and conveying fluid from the housing engagement surface  51  to at least one of the cap exterior  67  or the housing exterior  31  and away from the cap abutment surface  33  and the housing abutment surface  69 . 
         [0046]    A preferred passage means is at least one channel  21   a  in the cap engaging surface  61 . 
         [0047]    Thus, while the preferred embodiments of the present invention have been described with respect to the Figures, those skilled in the art will recognize that the present invention is capable of being modified and altered without departing from the teaching of the present application. Therefore, the present invention should not be limited to the precise details herein but should encompass the subject matter of the following claims.