Abstract:
A first valve head is selected for removal from a piston cylinder. The first valve head has been configured to house at least a one way intake valve assembly in an intake chamber of the head and at least a one way exhaust valve assembly in an exhaust chamber of the head. The intake and exhaust chambers are sealed off from each other. The first valve head is removed from the piston cylinder. A second valve head is selected. A bottom of the second valve head is removably coupled to the piston cylinder. A concentric two way valve is seated within the second valve head. The concentric valve is secured within said second valve head with a valve clamp having a top cover. The top cover is removably coupled to the second valve head.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    None 
       BACKGROUND OF THE INVENTION 
       [0002]    Industrial compressors include three basic types: reciprocating, rotary screw, and rotary centrifugal. A reciprocating compressor is a positive displacement machine wherein a piston travels inside a cylinder wherein the piston intakes compressible fluid into the cylinder on a down stroke and exhausts compressible fluid by compressing the compressible fluid on the upstroke. The exhausted compressible fluid travels through a valve that prevents the exhausted compressible fluid from coming back into the cylinder. Thus, multiple reciprocations of the piston causes a volume of compressible fluid to be exhausted into a fixed volume holding tank thereby increasing the pressure inside the holding tank on every reciprocation. The piston continues its reciprocation until a desired pressure is reached in the holding tank. As the compressible fluid inside the holding tank is exhausted out of the holding tank, the piston is then reciprocated as need to maintain a desired operating pressure. 
         [0003]    Essential components for any reciprocating compressor are the valve that allows compressible fluid to flow into the cylinder on the down stroke and the valve that allows compressible fluid to exhaust out of the cylinder during the upstroke. The valves experience millions of cycles during their operating life and when a valve fails or begins to cease to operate effectively, the efficiency and effectiveness of the compressor significantly deteriorates.  FIG. 1  illustrates a very common configuration a first stage of a reciprocating compressor assembly  200 . The assembly comprises a piston cylinder  202  having an inner diameter D 1  coupled to a valve head  204  with a seal  206  therebetween. The valve head  204  can also be called a cylinder head. Valve head  204  is a divided chamber head having an intake orifice  208  that allows compressible fluid to be drawn into an intake chamber  210 . Two intake valve assemblies  212  are seated within intake chamber  210  and configured to allow compressible fluid to enter the cylinder  202  during the piston&#39;s down stroke. For convenience only one of the two intake valve assemblies is shown. Each valve assembly includes a body  250 . The body is cylindrical and can be called a valve clamp or holder. The cylindrical body  250  carries a circular one way intake valve  253 . The valve carries one or more valve plates (not shown) which move from an open to a closed position. Each valve assembly  212  is a one way, modular, self contained valve assembly. Valve head  204  further comprises at least two exhaust valve assemblies  214  configured to allow compressible fluid to flow out of cylinder  202  during the piston&#39;s up stroke into exhaust chamber  216  and subsequently out exhaust orifice  218 . For convenience only one of the valve assemblies  214  is shown. Each valve assembly includes a body  254 . The body is cylindrical and can be called a valve clamp or holder. The cylindrical body carries a circular one way exhaust valve  257 . The valve carries one or more valve plates (not shown) which move from an open to a closed position. The valve assembly is a modular, one way, self contained valve assembly. Each body  250 ,  254  would also include a cap or closure (not shown) opposite the its valve. Each intake valve assembly  212  is coupled to the valve head  204  and in fluid communication with the intake chamber  210 . Each valve assembly  212  extends through respective openings  210 ′ and  210 ″ of chamber  210 . The openings lead into the interior of chamber  210 . Each intake valve assembly  212  extends into chamber  210 . Each exhaust valve assembly  214  is coupled to the valve head  204  and in fluid communication with the exhaust chamber  216 . Each valve assembly  214  extends through openings  216 ′ and  216 ″ of chamber  216 . The openings lead into an interior of chamber  216 . Each valve assembly  214  extends into chamber  216 . Chamber and openings  210 ,  210 ′,  210 ″ are separate, isolated and sealed off from chamber  216  and openings  216 ′,  216 ″. Valve assemblies  212  and  214  are coupled to valve head  204  with threading  220  as shown. Valve head  204  is coupled to piston cylinder  202  from above using a plurality of head fasteners  222  inserted through head apertures  227  and through cylinder apertures  224  in the cylinder flange  226  as illustrated. The valve head  204  carries a quad valve arrangement. The prior art also includes dual one way valve arrangements. In this case there is only one intake  212  and one exhaust  214  valve. The valve head is configured accordingly. 
         [0004]    Many of these multiple valve compressors have been in operation and the valves have reached the end of their functional life. In many of these cases the individual valves have, over the years, become very difficult to remove individually as the connections become fused, or the fasteners corrode to a point that it is extremely difficult to remove the individual valve that is not operating correctly. Further, if one valve is not functioning correctly, it becomes a decision whether to replace the other valves at the same time, or wait until the other valves fail on their own. Either option results in increased maintenance costs because replacing the valve before the end of its functional life is wasteful, but paying for maintenance personnel to return to the pump to replace the valve also involves an increase in maintenance costs. Moreover, as the relative labor to material cost differential has changed, the industry maintenance standard has become to remove the entire valve head and valves and replace it with a new or rebuilt valve head including new valves already installed into the head. This method, while more cost effective than trying to replace one or both valves individually, still generates considerable waste and consumes unnecessary maintenance cost resources. 
         [0005]    The vast majority of these compressors have a substantial remaining functional life. 
       SUMMARY OF THE INVENTION 
       [0006]    A method for retrofitting a reciprocating compressor embodies the invention. The method includes selecting for removal from a piston cylinder a first valve head. The first valve head is configured to house at least a one way intake valve assembly in an intake chamber of said head and at least a one way exhaust valve assembly in an exhaust chamber of said head. The intake and exhaust chambers sealed off from each other. The first valve head is removed from the piston cylinder. A second valve head is selected. A bottom of the second valve head is removeably coupled to the piston cylinder. A concentric two way valve is seated within the second valve head. The concentric valve is secured within the second valve head with a valve clamp having a top cover. The top cover is removably coupled to said second valve head. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0007]    The accompanying drawings form a part of the specification and are to be read in conjunction therewith, in which like reference numerals are employed to indicate like or similar parts in the various views, and wherein: 
           [0008]      FIG. 1  is a perspective view of a prior art embodiment of a quad valve head; 
           [0009]      FIG. 2  is a perspective view of one embodiment of a valve retrofit assembly in accordance with the teachings of the present invention; and 
           [0010]      FIG. 3  is a cross-section of the embodiment of the valve retrofit assembly of  FIG. 2  taken along the line  3 - 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0011]    The following detailed description of the invention references the accompanying drawing figures that illustrate specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The present invention is defined by the appended claims and the description is, therefore, not to be taken in a limiting sense and shall not limit the scope of equivalents to which such claims are entitled. 
         [0012]      FIG. 2  provides an example of a concentric valve head assembly  10  to retrofit the existing reciprocating compressor piston cylinder  202  shown in  FIG. 1  with the concentric valve head assembly shown in  FIG. 2 . The concentric valve head assembly  10  includes a valve head  12 ; a concentric valve  14  housed within valve head  12 ; valve clamp  16  that secures concentric valve  14  within valve head  12 . The assembly also includes seals  18  for preventing intake compressible fluid and exhaust compressible fluid from escaping their designated flow path. Valve head  12  can also be called cylinder head  12 . Valve head  12  includes a top  20 , a bottom  22 , a sidewall  24 , a top flange  26 , an intake orifice  28 , an exhaust orifice  30  and a central hollow  31 . Accordingly, sidewall  24  in part defines a substantially hollow valve head  12 . 
         [0013]    Sidewall  24  has an outer face  32  and an inner face  34  and has an axial length defined by top  20  and bottom  22  of valve head  12 . Further, outer face  32  of sidewall  24  may include annular ribs  36  around its circumference and may also include vertical ribs  38  spanning substantially from bottom  22  to top  20  and radially distributed around the circumference of outer face  32  as shown. The pattern of ribs  36  and  38  may serve in part to increase the stiffness of sidewall  24 . They may also provide for heat exchange with ambient air. Sidewall  24  may, alternatively, have a substantially smooth outer face and substantially uniform thickness (not shown). 
         [0014]      FIG. 3  shows top flange  26  extending around the circumference of top  20  of sidewall  24 . Flange  26  may also be called an end wall of head  12 . Top flange  26  includes a plurality of continuous head coupling apertures  40  that extend continuously and substantially vertical through top  20  and bottom  22  of sidewall  24 . Head coupling apertures  40  may be distributed around the circumference of top flange  26  in a known pattern that matches the pattern of cylinder apertures  224  of existing reciprocating compressor assembly  200 . Concentric valve head assembly  10  may be removably coupled to cylinder  202  of existing compressor assembly  200  with head fasteners  42  that extend through head coupling apertures  40  and into or through cylinder apertures  224 . Head fasteners  42  are configured to removably couple valve head  12  to cylinder  202  of  FIG. 1 . Fasteners  42  and fasteners throughout this disclosure may include bolts, screws, clamps, or any other fastening method now known or hereafter developed to result to removably couple two elements. Another embodiment of the present invention could include valve head  12  being permanently coupled to a cylinder through a permanent coupling method including welds or single casting. In this case the single piece casting would replace a separately cast existing head and cylinder. The existing head and cylinder to be replaced would have the same type of one way modular valves as discussed herein 
         [0015]    Valve head  12  may be configured and proportioned to be used with existing piston cylinders  202  of varying manufactures and diameters D 1 . Top flange  26  and the pattern and location of head coupling apertures  40  thereon may be configured to match the pattern of apertures  224  on an existing piston cylinder  202  of various manufacturers now known or hereafter developed. In this manner, a user may select a valve head  12  configured to be used with the piston cylinder  202  of a certain manufacturer having a certain size. 
         [0016]    Concentric valve  14  is a single modular element that performs dual functions and replaces the necessity of two one way valves. Concentric valve  14  is divided into at least two operable portions including an intake portion  46  and an exhaust portion  48 . One embodiment of concentric valve  14  has a circular shape and includes intake portion  46  including and surrounding the center of concentric valve  14  and exhaust portion  48  occupying the outer ring of concentric valve  14  as best shown in  FIG. 3 . One embodiment of the present invention can include intake portion  46  and exhaust portion  48  having substantially identical areas. Concentric valve  14 , includes two circular plates combined in one element. Valve  14  provides valved flow of fluid in at least two substantially opposing directions. A first plate  81  is at the top  80 . A second plate  85  is at the bottom  82 . The two plates are circular and can be called circular discs. The construction of concentric valves is known in the art and any such construction now known or hereafter developed may be incorporated into valve head assembly  10  of the present invention. Concentric valve  14  may also include a push rod assembly which includes a spring loaded plunger  50  whose main function is to move fingers  52  down thus holding the intake portion of valve  14  open and thus stopping the compression process. Air flows into intake  46  and back out without compression. 
         [0017]      FIG. 2  further shows valve clamp  16  including a top cover  54  that may include coupling tabs  56 . A recessed portion  57  is between each tab. Each tab has an aperture  58  there through. The configuration ensures that tabs  56  fit in-between head fasteners  42  when fasteners  42  are in an installed position in apertures  44  and the head  12  is coupled to cylinder  202 . Valve clamp  16  further includes an upper ring  60 , a plurality of vertical legs  62  positioned between upper ring  60  and a flow diverter  64 , and an exhaust rim  66  extending downwardly from flow diverter  64 . Vertical legs  62  are coupled to upper ring  58  and flow diverter  64  and distributed around the perimeter of upper ring  60  and flow diverter  64  to provide a plurality of voids for fluid flow therebetween. Exhaust rim  66  includes a plurality of exhaust apertures  68  through exhaust rim  66  and distributed around the circumference of exhaust rim  66  as shown in  FIG. 2  to allow compressible fluid to flow out of exhaust rim  66 . One o-ring  18  is seated on and around upper ring  60  and the other o-ring  18  is seated on and around flow diverter  64 . 
         [0018]    Now turning to  FIG. 3 , assembled valve head assembly  10  of the present invention is illustrated in cross section. As shown, inner face  34  of sidewall  24  is positioned at a radius R 1  from the center of valve head  12  and defines a single axially extending hollow passage way therethrough and outer face  32  is located at a radius R 2  from the center of valve head  12  wherein the difference between R 2  and R 1  substantially defines the thickness of sidewall  24 . Inner face  34  of sidewall  24  of valve head  12  further includes a recessed portion  70  around the entire circumference thereof as shown. This recessed portion substantially aligns with the position of intake orifice  28 . Further, inner face  34  of sidewall  24  includes a valve seat  72  that concentric valve  14  bears upon within valve head  12 . 
         [0019]    As shown, a portion of the circular valve plate at the bottom  82  of concentric valve  14  is seated on valve seat  72  and valve clamp  16  is inserted within the hollow defined by inner face  34  of valve head  12  such that exhaust rim  66  of valve clamp  16  bears against top  80  of concentric valve  14 . Concentric valve  14  may also be nested against inner face  34  of sidewall  24  by any other means known in the art including the outside of concentric valve being angled upward and outward and being wedged into a portion of inner face  34  similarly configured to receive concentric valve  14 . As further shown in  FIG. 3 , legs  62  are at the substantially same vertical position as intake orifice  28 . Each orifice  28  and  30  are in fluid communication with concentric valve  14 . Flow diverter  64  comprises a curved wall  74  that also bears against concentric valve  14  separating the intake portion  46  from exhaust portion  48  of concentric valve  14  thereby separating the intake and exhaust fluid flow. Curved wall  74  of flow diverter  64  defines an opening having a diameter D 2  that substantially corresponds to the diameter of the intake portion of concentric valve  14 . Flow diverter  64  and the configuration of valve head  12  and valve clamp  16  generally provides intake portion  46  of concentric valve  14  being in fluid communication with intake orifice  28  and exhaust portion  48  of concentric valve  14  being in fluid communication with exhaust orifice  30 . One embodiment of valve assembly  10  may include a downward extending rod  78  of top cover  54  of valve clamp  16  encircling a portion of plunger  50 . 
         [0020]    To secure concentric valve  14  within valve head  12  with valve clamp  16 , a plurality of clamp fasteners  76  are inserted through apertures  58  of top cover  54  of valve clamp  16  and into clamp apertures  44  of top flange  26  and operated to removably couple valve clamp  16  to valve head  12 . One or more seals or o-rings  18  may be positioned on upper ring  60  of valve clamp  16  or any component thereof to prevent compressible fluid from exiting around the valve clamp  16  and out the valve head  10  as shown in  FIG. 3 . Additional seals or o-rings  18  may be positioned on and around the flow diverter  64  of valve clamp  16  to prevent fluid from exiting out of valve head  10  in an undesired path. 
         [0021]    Valve head assembly  10  of the present invention is used to retro-fit existing piston cylinders  202  of a reciprocating compressor assembly  200  by replacing a quad-valve valve head  204  with valve head assembly  10  that incorporates a concentric valve  14 . Replacing quad-valve head  204  with valve head assembly  10  results in more efficient operation of the reciprocating compressor and substantially reduces maintenance costs with respect to replacing warn out valves. To affect replacement, a user will first remove the existing quad-valve head  204  and all the valves  212  and  214 . The head is removed with the valves by releasing a plurality of fasteners  222 . Seal  206  is removed and cylinder flange  226  of piston cylinder  202  is cleaned and prepared to receive valve head  12  of valve assembly  10 . A replacement seal, sealant, or combination thereof may be placed between valve head  12  and cylinder flange  226  to provide an air-tight seal. Although  FIG. 1  shows a quad valve, it is within the scope of the invention to replace a dual valve head. In this case the valve head replaced only carries one intake valve  212  and one exhaust valve  214 . 
         [0022]    Valve head  12  is placed in contact with cylinder flange  226  and aligned such that head coupling apertures  40  are aligned with apertures  224  in cylinder flange  226 . Head fasteners  42  are inserted into and extended through head coupling apertures  40  and are extended through or received by apertures  224  through flange  226 . Fasteners  42  may be tightened to securely and removably couple valve head  12  to piston cylinder  202 . 
         [0023]    Concentric valve  14  is placed into hollow valve head  12  such that a portion of the circular plate form the bottom  82  of concentric valve  14  rests upon valve seat  72 . Valve clamp  16  is inserted into hollow valve head  12  such that exhaust rim  66  bears against top valve  81  of concentric valve  14  and downward extending arm or protrusion  78  of top cover  26  encircles plunger  50 . In one embodiment of the present invention, plunger  50  may be displaced slightly downward to hold the inlet portion of valve  14  open and stop compression. Valve clamp  16  is then positioned such that apertures  58  align with clamp apertures  44  on top flange  26 . Fasteners  76  are inserted through apertures  58  and are received into clamp apertures  44  to couple valve clamp  16  to valve head  12 . Existing intake and exhaust pipes may be coupled to valve head  12  and the reciprocating compressor is ready for operation. 
         [0024]    In operation, when the piston in piston cylinder  202  is stroked and repeatedly translated upward and downward within piston cylinder  202 , compressible fluid is drawn in through intake orifice  28  of valve head  12  during the down stroke wherein the fluid flows through the voids between vertical legs  62  and is diverted by curved wall  74  of flow diverter  64  into intake portion  46  of concentric valve  14 . Intake portion  46  of concentric valve  14  opens to allow intake compressible fluid to be drawn into cylinder  202 . Upon the up-stroke of the piston  228  within cylinder  202 , compressible fluid in cylinder  202  is compressed upward. Intake portion  46  of concentric valve  14  closes and exhaust portion  48  of concentric valve  14  opens allowing compressible fluid to be forced out of cylinder  202 , through concentric valve  14  and apertures  68  in exhaust rim  66  and out exhaust orifice  30 . The Piston of the reciprocating compressor  200  cycles repeatedly until one or both of concentric valve portions  46  of  48  wears out. 
         [0025]    At this point, a user will remove valve clamp  16  by releasing or removing fasteners  76  and pulling valve clamp  16  upward and out of hollow valve head  12 . The user may then remove concentric valve  14  by pulling it upward off of seat  72  and remove it from valve head  12 . The user may then insert a new concentric valve  14  such that new concentric valve  14  seats on valve seat  72  and the user may then re-insert valve clamp  16  into hollow valve head  12  and couple top cover  54  to valve head  12  as described above. 
         [0026]    The retro-fit of an existing reciprocating compressor with the valve head assembly  10  of the present invention as described above substantially reduces the time and materials required to maintain the reciprocating compressors and increases the efficiency of the existing compressors by allowing the valve to be immediately proximate the piston of the reciprocating compressor. 
         [0027]    From the foregoing it will be seen that this invention is one well adapted to attain all ends and objects hereinabove set forth together with the other advantages which are obvious and which are inherent to the structure. 
         [0028]    It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims. 
         [0029]    Since many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative, and not in a limiting sense.