Patent Publication Number: US-3875756-A

Title: Method for maintaining and servicing a pressurized refrigeration system or the like

Description:
United States Patent Olson METHOD FOR MAINTAINING AND SERVICING A PRESSURIZED REFRIGERATION SYSTEM OR THE LIKE [75] Inventor: John W. Olson, Garland. Tex.  
 [73] Assignee: C &amp; I) Valve Manufacturing Company, Oklahoma City. Okla.  
 [22] Filed: June 28, I974 [2|] Appl. No.: 484.298  
 Related U.S. Application Data Division of Ser. No. 378.920 July 13. 1973, Pat. No. 3.840967. which is a continuation-in-part of Ser. No. 343,5l2. March Ill. 1973, abandoned.  
 Primary E.\&#39;aminwMcyer Perlin Attorney. Agent, or Firm Laney, Dougherty, Hessin &amp; Fish [57] ABSTRACT A tool for maintaining and servicing a pressurized refrigeration system or the like therein it is desirable to remove and replace a threaded check valve core without depressurizing the system. The tool includes a body member having a longitudinal passageway extending therethrough with means to provide sealing communication between one end of the passageway with the fitting in which the check valve is fitted. A removable cap sealingly engages the opposite end of the longitudinal passageway with an operating shaft extending therethrough for axial and rotary movement within the passageway. An annular sliding seal is disposed between the shaft and the removable cap. The shaft includes engaging means formed on one end thereof for releasably engaging the valve core to unthread and remove it from the fitting and withdraw it into the passageway to a position adjacent to the removable cap. A shut-off valve is mounted in the body member to alternately close and open the passageway when the valve core is withdrawn into the passageway adjacent to the cap. An additional port in the body member communicating with the passageway is also disclosed for evacuating or charging the refrigeration system through the passageway. A method for removing and replacing the valve core employing the tool is also disclosed.  
 4 Claims, 5 Drawing Figures METHOD FOR MAINTAINING AND SERVICING A PRESSURIZED REFRIGERATION SYSTEM OR THE LIKE CROSS-REFERENCE TO RELATED APPLICATION This is a Division of application Ser. No. 378,920 filed July 13, [973, and now U.S. Pat. No. 3,840,967 which is a Continuation-in-part of application Ser. No. 343,5 [2 filed Mar. 21, i973 and now abandoned.  
 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to method and apparatus for maintaining and servicing a pressurized system such as a refrigeration system or the like, and more particularly, but not by way of limitation, to method and apparatus for removing and replacing a closure member in a pressurized refrigeration system without depressurizing the system.  
 2. Description of the Prior Art The prior art contains a number of teachings of servicing tools which provide access to a refrigeration system or the like to evacuate or charge the system. One such tool is disclosed in US. Pat. No. 3,299,648, issued to White, et al.  
  It should be noted, that neither the White tool nor any other known tools permit the removal and replacement of the threaded closure member in a pressurized refrigeration system without depressurizing the system.  
  lt has become common practice in the refrigeration industry to provide access to pressurized refrigeration systems through threaded fittings in which a threaded check valve core is installed. Such threaded check valves are of the type commonly used in automobile tire valve stems and are often referred to as Schradertype valve cores.  
  It has been found that the Schrader-type valve cores used in refrigeration systems are not subject to extremely high quality control measures. Approximately 50% of the valve cores initially installed in a refrigeration system are found to be incapable of holding the proper operating pressure to permit efficient operation of the refrigeration system. It is, therefore, necessary many times to replace an unsatisfactory valve core after Charging a refrigeration system with refrigerant. It is to this industry-wide problem that the method and apparatus of the present invention is directed.  
 SUMMARY OF THE INVENTION The present invention contemplates a tool for use in maintaining and servicing a refrigeration system or the like equipped with an access fitting provided with a removable threaded closure member therein. The tool includes a body member having a first end and a second end and having a longitudinal passageway extending therethrough and communicating at the opposite ends thereof with the first and second ends of the body member. Coupling means is carried on the first end of the body member for removably connecting the first end of the body member to the access fitting with one end of the longitudinal passageway in sealing communication with the access fitting. Removable cap means is provided which is securable to the second end of the body member for sealing closure of the opposite end of the longitudinal passageway, and, alternately, for removal from the body member and includes an aperture formed therein substantially coaxial with the longitudinal passageway. An operating shaft is provided which includes a first end and a second end and which extends through the aperture in the removable cap means, with the first end thereof disposed within the longitudinal passageway and with the second end thereof disposed outside the longitudinal passageway. The removable cap means carries seal means for providing slidingly and rotatingly sealing engagement between the aperture in the cap means and the operating shaft so that the operating shaft may be moved axially and rotatably within the longitudinal passageway. The first end of the operating shaft is secured to engaging means for releasably engaging the threaded closure member in the access fitting. Control means operatively engages the sec and end of the operating shaft for rotating and axially displacing the engaging means within the longitudinal passageway in response to stimulus external thereto. Valve means is carried by the body member intermediate the first and second ends thereof for alternately opening and closing the longitudinal passageway, the valve means being adapted to close the longitudinal passageway when the operating shaft is displaced toward the second end of the body member. Actuating means operatively engages the valve means for moving the valve means between a position opening and a position closing the longitudinal passageway in response to stimulus external thereto.  
  An object of the present invention is to provide an efficient tool for maintaining and servicing a pressurized refrigeration system or the like.  
  Another object of the present invention is to provide an improved method and tool for maintaining and servicing a pressurized refrigeration system which allows the removal and replacement of a defective access valve core in a pressurized refrigeration system without requiring depressurization of the system.  
  A further object of the present invention is to provide an improved method and apparatus for maintaining and servicing a pressurized refrigeration system which permits the removal and replacement of a defective access valve core in a refrigeration system and further permits the evacuation and/or recharging of the system by means of the same tool.  
  A still further object of the present invention is to provide a tool for maintaining and servicing a pressurized refrigeration system or the like which is economical to manufacture and simple to operate.  
  Other objects and advantages of the present invention will be evident from the following detailed description when read in conjunction with the accompanying drawings.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic diagram of a refrigeration system with the tool of the present invention connected to the high pressure side of the compressor.  
  FIG. 2 is a cross-sectional view of one embodiment of the present invention illustrating the engaging means in engagement with the threaded check valve of the refrigeration system and with the valve means opening the passageway of the tool.  
  FIG. 3 is a cross-sectional view similar to FIG. 2 illustrating the threaded check valve fully withdrawn from the refrigeration system into the passageway of the tool and with the valve means closing the passageway.  
  FIG. 4 is a cross-sectional view similar to FIG. 3 illustrating the threaded check valve removed from the tool for inspection and replacement.  
  FIG. 5 is an enlarged partial cross-sectional view il lustrating the construction details of the valve core engaging chuck on the operating shaft.  
  FIG. 6 is a cross-sectional view of an alternate em bodiment of the present invention.  
  FIG. 7 is a cross-sectional view of another form of the present invention.  
 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings and to FIGS. l5 in particular, the apparatus of the present invention is generally designated by the reference character 10.  
  The apparatus 10 is a tool which includes a body member 12 having a first end portion 14 and a second end portion 16. A cylindrical bore 18 extends through the body member 12 communicating with the first and second end portions 14 and 16 thereof forming a longi tudinal passageway through the body member 12. The outer periphery 20 ofthe body member 12 adjacent to the first end portion 14 is cylindrically shaped. A circumferential groove 22 is formed in the outer periphcry 20 and includes first and second cylindrical surfaces 24 and 26 interconnected by an inclined surface 28. The diameter of the second cylindrical surface 26 is greater than the diameter of the first cylindrical surface 24.  
  A coupling nut 30 is rotatably secured to the first end portion 14 of the body member 12. The coupling nut 30 includes a cylindrically shaped inner peripheral portion 32 slidingly disposed around the outer periphery 20 of the body member 12. The coupling nut 30 is retained on the body member 12 by means ofa snap ring 34 carried in an annular groove 36 formed in the inner peripheral portion 32 and engaging the circumferential groove 22 in the body member 12.  
  Internal threads 38 are formed in the outer end por tion 40 ofthe coupling nut 30. A suitable annular Neoprene gasket 42 is positioned within the coupling nut 30 between the threads 38 thereof and the first end portion 14 of the body member 12.  
  External threads 44 are formed on the outer periph ery of the body member 12 adjacent to the second end portion 16 thereof. An access cap 46 is threadedly secured to the second end portion 16 of the body member 12 by means of internal threads 48 formed therein and threadedly engaging the external threads 44 of the body member 12. The access cap 46 includes a bore 50 formed therein coaxial with the access of the bore 18 formed in the body member 12. A first counterbore 52 is formed in the access cap 46 coaxial with the bore 50. A second countenbore 54 is formed in the access cap 46 coaxial with the first counterbore 52 in the bore 50. An annular retainer 56 having a cylindrically shaped outer periphery 58 having a diameter slightly less than the diameter of the second counterbore 54 is positioned within the second counterbore 54 intermediate the internal threads 48 and the first counterbore 52 formed therein.  
  An operating shaft 60 having a cylindrically shaped outer periphery extends through the bore 50 in the access cap 46 and through the annular retainer 56. The first end portion 62 ofthe operating shaft 60 is disposed within the bore 18 of the body member 12. A control knob 64 is rigidly secured to the second end portion 66 of the operating shaft 60 by means of a set screw 68 threadedly secured in the control knob 64 and bearing against the second end portion 66 of the operating shaft 60.  
  A pair of O-rings 70 are positioned within the first counterbore 52 of the access cap 46 and provide a fluid-tight seal between the access cap 46 and the operating shaft 60. The fluid-tight seal obtained by the 0 rings 70 permits the operating shaft to be axially and rotatably displaced relative to the access cap 46 without fluid leakage thereby. The O-rings 70 are retained in proper position within the first counterbore 52 by the annular retainer 56. A fluid-tight seal is obtained between the access cap 46 and the second end portion 16&#39; of the body member 12 by means of an O-ring 72 positioned therebetween.  
  The threads 44 on the body member 12 and the threads 48 on the access cap 46 are suitably formed such that when the cap 46 is removed from the body member 12 suitable means for evacuating and charging (not shown) a refrigeration system may be threadedly engaged to the threads 44 to provide sealing engagement between said means and the body member 12 so that a refrigeration system may be evacuated and charged with refrigerant through the cylindrical bore 18 through the body member 12. A suitable. and industry-accepted thread for this purpose is 7116-20 thread.  
  As most clearly shown in FIG. 5, a suitable valve core engaging chuck 74 is secured to a reduced portion 76 of the operating shaft 60 by a roll pin 78. An O-ring 80 is secured within a counterbore 82 formed in the chuck 74 near the bifurcated end therof and is retained in proper position by the reduced portion 76 of the operating shaft 60 adjacent thereto. An axial bore 84 is formed in the first end portion 62 of the operating shaft 60 for receiving the extending head of the valve core being engaged by the chuck 74. A transverse slot 86 is formed in the chuck 74 for receiving the rectangular portion of the valve core therein for threading and unthreading the valve core in its fitting. A bore 88 is also formed in the chuck 74 coaxial with the counter-bore 82 for receiving the head of the valve core there&#39; through. The inner diameter of the resilient O-ring 80 is sized such that a valve core engaged by the chuck 74 will be releasably retained thereby by means of the engagement of the head of the valve core by the O-ring 80.  
  A shut-off valve assembly 90 is carried by the body member 12. The shut-off valve assembly 90 includes a valve fitting 92 suitably formed on the body member 12 and extending outwardly therefrom. A lateral bore 94 extends through the valve fitting 92 and partially through the body member 12 intersecting the cylindrical bore 18 through the body member 12. The axis of the lateral bore 94 intersects the axis of the cylindrical bore 18 and is normal thereto. The diameter of the lateral bore 94 is greater than the diameter of the cylindrical bore 18. The lower end of the bore 94 extends completely through the cylindrical bore 18 and terminates in a flat circular wall 96 formed in the body member 12.  
  A valve stem 98 is positioned within the lateral bore 94. A control knob 100 is fixedly secured to the upper end 102 of the valve stem 98 by means of a set screw 104.  
  A cylindrically shaped resilient valve member 106 is fixedly secured to the lower end 108 of the valve stem 98. The valve member 106 is preferably formed of a short length of resilient tubing formed of a suitable material such as Neoprene. The outer diameter of the valve member 106 is substantially equal to the diameter of the lateral bore 94 and the axial length of the valve member 106 is greater than the diameter of the cylindrical bore 18 extending through the body member 12. The valve member 106 may be secured by a suitable adhesive to the cylindrical outer periphery of the lower end 108 of the valve stem 98.  
  A pair of spaced circumferential ribs 110 and 112 are formed on the valve stem 98 with the rib 110 abutting the upper end of the resilient valve member 106. An O-ring 114 is positioned between the circimferential ribs 110 and 112 and provides a fluid-tight seal between the valve stem 98 and the lateral bore 94. External threads 116 are formed on the valve stem 98 and extend between the control knob 100 and the circumferential rib 112.  
  The valve stem 98 is secured within the valve fitting 92 by means of a valve fitting cap 118 threadedly secured to the valve fitting 92. The external threads 116 ofthe valve stem 98 are threadedly engaged with inter nal threads 120 formed in an aperture 122 in the valve fitting cap 118 through which the valve stem 98 extends.  
  It will be seen that by rotating the control knob 100 the valve stem 98 will move axially within the lateral bore 94 as the valve stem 98 is alternately threaded and unthreaded in the valve fitting cap 118. FIG. 2 illustrates the shutoff assembly 90 in the open position with the resilient valve member 106 fully retracted within the lateral bore 94. FIG. 3 illustrates the shut-off valve assembly 90 in the closed position with the resilient valve member 106 closing the cylindrical bore 18 through the body member 12. It will be seen that the resilient valve member 106 extends slightly below the lower end 108 of the valve stem 98. This permits the valve stem 98 to be threaded to a point wherein the lower end 108 thereof engages the flat circular wall 96 in the body member 12. In this position the resilient valve member 106 is axially compressed and forms a fluid-tight seal closing the cylindrical bore 18 in the body member 12.  
  It should be noted at this point that the valve fitting 92 may be in the form ofa separate component suitably secured to the body member 12 by means such as soldering or brazing. or the valve fitting 92 and the body member 12 may be integrally formed in one piece.  
  FIG. 1 schematically illustrates a conventional refrigeration system to which the apparatus is connected. The refrigeration system includes a compressor 124 having its high-pressure side connected by means of conduit 126 to the inlet of a condensor 128. The outlet of the condensor 128 is connected by conduit 130 to an expansion valve 132. The expansion valve 132 is connected by means of conduit 134 to the inlet of an evaporator 136. The outlet of the evaporator 136 is connected by conduit 138 to the low&#39;pressure side of the compressor 124 thereby completing the refrigeration loop.  
  An access fitting 140 is shown connected to the conduit 126 adjacent to the high-pressure side of the compressor 124. The access fitting 140 is ofthe type which includes a threaded check valve core 142 installed therein. The valve core 142 is of the type which is typi cally referred to as a Schrader-type valve core. Such valve cores are commonly used in automotive tires and the like.  
  FIGS. 2-4 illustrate the tool 10 installed on the ac&#39; cess fitting 140 with the coupling nut 30 threadedly secured to the external threads 144 of the access fitting 140 and with the gasket 42 providing a fluid-tight seal between the outer end of the access fitting 140 and the first end portion 14 of the body member 12 of the tool 10. The valve core 142 is shown properly secured by the valve core engaging chuck 74.  
 OPERATlON OF THE PREFERRED EMBODIMENT To operate the tool 10, the tool 10 is connected to a suitable access fitting 140 by means of the coupling nut 30 as shown in FIGS. 1 and 2. The shutoff valve assem bly is placed in the open position as illustrated in FIG. 2 and the operating shaft 60 is moved to the left as viewed in FIG. 2 where the core engaging chuck 74 is suitably engaged with the valve core 142 which is to be removed from the access fitting 140.  
  The valve core 142 is then unthreaded by turning the control knob 64 counterclockwise. When the valve core 142 is completely unthreaded from the access fitting 140 the control knob 64 is withdrawn as far to the right as possible as illustrated in FIG. 3. The shut-off valve assembly is then actuated to close the cylindrical bore 18 through the body member 12. This is accom plished by rotating the control knob in a clockwise direction until the lower end of the valve stem 108 seats on the flat circular wall 96 in the valve body 12 thereby providing a fluid-tight seal in the tool 10.  
  The access cap 46 is then unthreaded from the body member 12, and the access cap 46. operating shaft 60 and the valve core 142 are removed from the body member 12.  
  At this point suitable means for evacuating and charging (not shown) a refrigeration system is threadedly secured to the threads 44 of the body member 12 to provide sealing communication between said means and the access fitting via the cylindrical bore 18 through the body member 12. The shut-off valve assembly is then actuated to open the bore 18 through the body member 12. The refrigeration system carrying the access fitting 140 may then be evacuated and charged with refrigerant through the tool 10. When the refrigeration system is charged, the shut-off valve assembly is again actuated to close the bore 18 as described above, and the evacuating and charging means is removed from the tool 10.  
  The valve core 142 may then be inspected and replaced if necessary. The new valve core 142 is secured to the valve core engaging chuck 74 and reinserted into the cylindrical bore 18 along with the operating shaft 60. The access cap 46 is rethreaded into sealing engagement with the body member 12.  
  The shut-off valve assembly 90 is then opened fully by rotating the control knob 100 in a counterclockwise direction until the resilient valve member 106 is fully withdrawn into the lateral bore 94 thereby opening the cylindrical bore 18.  
  The control knob 64 is then moved to the left until the check valve core 142 engages the access fitting 140. The check valve core 142 is then rethreaded into the access fitting 140 by rotating the control knob 64 in a clockwise direction until the check valve core sealingly engages the access fitting 140. At this time the tool 10 may be removed from the access fitting 140 by unthreading the coupling nut 30.  
 DESCRIPTION OF THE EMBODIMENT OF FIG. 6  
  FIG. 6 illustrates a slightly modified tool 10a which includes an evacuating and charging fitting I46 formed on and extending outwardly from a slightly modified body member 120. The fitting I46 includes a laterally extending port 148 extending therethrough and communicating between the outer end thereof and the cylindrical bore I8 through the body member 12a. A conventional threaded check valve core of the Schradertype I50 is threadedly secured within the fitting I46. The fitting 146 further includes external threads 152 formed thereon to provide means for engagement with suitable means for evacuating and charging (not shown) a refrigeration system through the tool 100.  
 OPERATION OF THE EMBODIMENT OF FIG. 6  
  in operation the tool 100 is first secured to the access fitting I40 as described above. Similarly, the check valve core 142 is removed from the access fitting 140 and withdrawn fully to the right within the bore 18 as viewed in FIG. 6. With the shut-off valve assembly 90 in the open position, the refrigeration system may now be evacuated and charged through the evacuation and charging fitting I46.  
  It will be readily apparent that the tool 10a may also be used to remove and replace a defective check valve core I42 as described in detail above for the tool 10. This should preferably be done prior to evacuating and charging the refrigeration system.  
 DESCRIPTION OF THE EMBODIMENT OF FIG. 7  
  FIG. 7 illustrates another slightly modified tool 10b, similar to the tool 100 described above. The tool 10b differs from the tool 100 in that the evacuation and charging fitting 146 is formed on the slightly modified body member l2b in coaxial alignment with the lateral bore 94 of the shut-off valve assembly 90. It will be seen that the port 148 of the evacuation and charging fitting 146 communicates with the interior of the body member 12b through the flat circular wall 96 formed therein.  
  The configuration of the tool 10b permits a slightly shorter body member 12b, and simplifies machining required in the construction of the tool 10b.  
  Operation of the tool 10b is identical to that described for the tool 10a and therefore will not be described in detail again.  
  It will be seen from the foregoing detailed description of the present invention that the various embodiments thereof and the methods for their utilization described therein readily obtain the objectives set forth. Changes may be made in the construction and arrangement of parts or elements of the various embodiments described herein without departing from the spirit and scope of the present invention as defined herein.  
 What is claimed is:  
  l. A method of servicing the compressor of a refrigeration system through a threaded access fitting having a threaded closure member threadedly sealingly engaged therewith, comprising the steps of:  
 sealingly engaging said access fitting with the first end of a tool having a sealed passageway formed therein and communicating with the first end of said tool and having a removable end cap sealingly engaging the opposite end of said passageway, said tool having valve means disposed on said passageway intermediate the first end of said tool in the opposite end of said passageway and movable between a position opening said passageway and a position closing said passageway, and having evacuating and charging lines communicating with said sealed passageway intermediate said valve means and the opposite end of said passageway;  
 unthreading said threaded closure member from said access fitting and withdrawing said threaded closure member to a position within said passageway adjacent to said removable end cap;  
 moving said valve means from the position opening said passageway to the position closing said passageway;  
 removing said end cap from said tool;  
 removing said threaded closure member from said passageway;  
 positioning a replacement threaded closure member in said passageway adjacent to the opposite end thereof;  
 replacing said end cap on said tool to sealingly engage the opposite end of said passageway;  
 moving said valve means from the position closing said passageway to the position opening said passageway;  
 discharging the refrigerant from said compressor through said evacuating line;  
 charging the compressor with refrigerant through said charging line; and  
 moving said replacement threaded closure member through said passageway to said access fitting and rethreading said threaded closure member into said fitting into sealing engagement therewith. 2. The method as defined in claim 1 characterized further to include the additional step of:  
  removing said tool from said access fitting. 3. A method of servicing a pressurized refrigeration system having an access fitting formed thereon, with the access fitting having a threaded closure member in threaded sealing engagement therewith, employing evacuating means and refrigerant charging means, comprising the steps of:  
 sealingly engaging said access fitting with the first end of a tool having a sealed passageway formed therein and communicating with the first end of said tool and having a removable end cap sealingly engaging the opposite end of said passageway, and having valve means disposed in said passageway intermediate the first end of said tool and the opposite end of said passageway and movable between a position opening said passageway and a position closing said passageway; unthreading said threaded closure member from said access fitting and withdrawing it to a position within said passageway intermediate said valve means and the opposite end of said passageway;  
 moving said valve means from the position opening said passageway to the position closing said passageway;  
 removing said end cap from said tool;  
 removing said threaded closure member from said passageway;  
 positioning a threaded closure member in said passageway;  
 replacing said end cap on said tool to sealingly engage the opposite end of said passageway;  
 5 moving said valve means from the position closing said passageway to the position opening said passageway; and  
 moving said threaded closure member through said passageway to said access fitting and rethreading said threaded closure member into said access fitting into sealing engagement therewith.  
 4. The method as defined in claim 3 characterized further to include the additional step of: removing said 5 too] from said access fitting.