Abstract:
A method and apparatus for servicing a pressurized system is described. A purge fitting can be used to vent the pressurized system. Venting can release a gas, such as air, from the system. The pressurized system can be a climate control system (e.g., an air conditioning or refrigeration system), a brake system, a hydraulic system, or a service device for servicing a climate control system. The purge fitting allows air that may be trapped in the pressurized system to be vented by depressing a purge actuator, such as a purge button attached to the fitting. The air can be vented from an opening adjacent to the actuator or other orifice. By purging air directly from the system, the amount of air introduced into the system during servicing can be minimized. The invention also features a coupling member that can be compact in size. The coupling member can include a self-sealing valve assembly that prevents opening the coupling member until a proper coupling interconnection with a system to be serviced has taken place. The purge fitting can be incorporated in the coupling member or other service device.

Description:
CLAIM OF PRIORITY 
   This application is a continuation of and claims priority to U.S. application Ser. No. 09/422,236 filed on Oct. 21, 1999, now U.S. Pat. No. 6,539,970, the entire contents of which is hereby incorporated by reference. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to a method and apparatus for servicing a pressurized system, in particular an air conditioning or refrigeration system. 
   Servicing couplings are commonly employed to facilitate charging and evacuation of a pressurized fluid system, such as a refrigeration system, an air conditioning system, or a hydraulic system. The service coupling connects to a service port of the system. The service coupling opens a service port of a system, allowing fluids, including liquids or gases, to be exchanged with the system. A quick-release interconnection between the service port and the service adapter can facilitate the servicing process. For example, when servicing a refrigeration or air conditioning system the service coupling can be connected by a flexible hose to a refrigerant supply source, such as a pressurized bottle or cylinder. When the service coupling and service port is opened, refrigerant can flow through the coupling and into the refrigeration system. Because pressurized fluid systems can be serviced when the system is installed in a confined space such as a vehicle, service couplings having small dimensions can be useful for convenient servicing. 
   In order to maintain the performance of a pressurized fluid system, it can be important to keep air out of the system. In air conditioning systems, for example, system performance can deteriorate when air is in the system. In addition, introduction of air can also lead to introduction of moisture and other contaminants into the system. Thus, keeping air out of the system can be important when servicing a system. 
   SUMMARY OF THE INVENTION 
   The invention features a purge fitting for venting a pressurized system. Venting can release a gas, such as air, from the system. The pressurized system can be a climate control system (e.g., an air conditioning or refrigeration system), a brake system, a hydraulic system, or a service device for servicing a climate control system. The purge fitting allows air that may be trapped in the pressurized system to be vented by depressing a purge actuator, such as a purge button attached to the fitting. The air can be vented from an opening adjacent to the actuator or other orifice. By purging air directly from the system, the amount of air introduced into the system during servicing can be minimized. The service device can be a coupling member or a service unit. The invention also features a coupling member that can be compact in size. The coupling member can include a self-sealing valve assembly that prevents opening the coupling member until a proper coupling interconnection with a system to be serviced has taken place. The purge fitting can be incorporated in the coupling member or other service device. 
   In one aspect, the invention features a coupling member. The coupling member includes a body having a first end engageable with a first valve, a second end having a moveable control member, an inner surface defining an interior chamber, and a port in fluid communication with the interior chamber. The first valve can be a service port. The coupling member also includes a pusher disposed in the interior chamber and in contact with the control member. The pusher has a valve actuation portion extending toward the first end of the body. The pusher is movable by the control member from a valve closed position to a valve open position. The coupling member also includes a pin depressor proximate to the port having a first position oriented closer to the interior chamber relative to a second position which is closer to the port. The pin depressor moves from the first position to the second position when the first valve is engaged with the first end of the body and the pusher is moved from the valve closed position to the valve open position. The pin depressor is in the first position when the first end of the body is not engaged with the first valve and the pusher is moved from the valve closed position to the valve open position. 
   The pusher can be engaged with threads to the control member. The pusher can move from the valve closed position to the valve open position by rotating the control member by less than one revolution. The second end of the body can include a groove. The control member can be moveably attached to the groove. Attachment can be made by a pin assembly, a set screw, or a snap ring. 
   The coupling member can also include a valve detection member movably disposed on the valve actuation portion. The valve detection member can be rotatably or slidably disposed on the valve actuation portion. The valve detection member moves relative to the valve actuation portion when the first valve is engaged with the first end of the body and the pusher is moved from the valve closed position to the valve open position. The valve detection member is substantially stationary relative to the valve actuation portion when the first end of the body is not engaged with the first valve. The pin depressor moves from the first position to the second position when the valve detection member moves relative to the valve actuation portion. 
   The coupling member can include a second valve positioned within the port. The second valve is opened when the pin depressor moves from the first position to the second position. The first end can be engageable with a high pressure side refrigerant port or a low pressure side refrigerant port. 
   In preferred embodiments, the pin depressor is movably attached to the pusher. 
   In other preferred embodiments, the first end of the body includes a release sleeve assembly including an adapter connected to the first end of the body, a release sleeve over the adapter, and a spring between the release sleeve and the adapter. The adapter can be connected by threads, pins, one or more set screws, a snap ring, brazing, or soldering. The release sleeve assembly can include a plurality of balls distributed between the adapter and the sleeve. The balls are engageable with the first valve. The plurality of balls can include more than six balls (e.g., eight balls). 
   In other preferred embodiments, the coupling member includes a purge actuator exterior to the body. The purge actuator has a shaft extending through the interior chamber to the port. The shaft is capable of moving the pin depressor from the first position to the second position while in the valve closed position. In certain embodiments, the pusher can include a stop that prevents the shaft from moving the pin depressor when in the valve open position. 
   The purge actuator can include a button, a switch, a lever, a knob, or a rocker. 
   In preferred embodiments, the coupling member has an end-to-end dimension T that is unchanged in the valve open position and in the valve closed position. 
   In another aspect, the invention features a coupling member including a first end engageable with a service port, a valve within the coupling member, and a purge actuator capable of opening the valve. The coupling member can also include a service port detection member movably disposed within the coupling member. The service port detection member opens the valve when the service port is engaged with the first end. The port detection member does not open the valve when the first end is not engaged with the service port. The coupling member can be a release sleeve assembly at the first end including an adapter connected to the first end, a release sleeve over the adapter, and a spring between the release sleeve and the adapter. 
   In another aspect, the invention features a purge fitting. The purge fitting includes a body having a fluid inlet, a fluid outlet, and a vent port. The purge fitting also can include a purge actuator exterior to the body. The purge actuator has an open position and a closed position. The purge actuator seals the vent port when the actuator is in the closed position. The seal is broken and the vent port is opened when the purge actuator is in the open position. The fluid inlet and the fluid outlet are in fluid communication when the purge actuator is in the closed position, and the vent port, the fluid inlet and the fluid outlet are in fluid communication when the purge actuator is in the open position. Flow between the fluid inlet and the fluid outlet is substantially unrestricted when the purge actuator is in the open position and the closed position. 
   The purge actuator can include a shaft extending into the body to a shaft retaining member. The purge actuator can have a diameter that covers the vent port without blocking fluid flow. The body of the purge fitting can be a portion of a coupling member, a portion of a hydraulic system, a brake system, or a portion of a climate control system service unit. The service unit can be a service manifold, a valve core removal tool, a refrigerant cylinder, a fluid charge line, such as a hose, a refrigerant identifier or analyzer, a diagnosis instrument, a dye injector, a recovery and recycle station, or other device that can connect to a service port of a system. 
   In yet another aspect, the invention features a method of servicing a pressurized fluid system. The method includes attaching a coupling member to a service port of the system, the coupling member being connected to a service unit and including a safety valve, and opening the service port with the coupling member. The safety valve is opened by a valve detection member in the coupling member approximately when the service port is opened. The coupling member or the service unit can include a purge actuator. The purge actuator or coupling member can be manually activated or automatically activated by, for example, a control circuit. The method can include activating the purge actuator to vent air from the service unit prior to attaching the coupling member to the service port or prior to opening the service port. The service port can be a high pressure side refrigerant port or a low pressure side refrigerant port. 
   In yet another embodiment, the invention features a method of venting a pressurized system including moving a purge actuator from a closed position to an open position. The purge actuator can be a portion of a purge fitting or a portion of a coupling member. The pressurized system can be a service device or a climate control system. The climate control system can be an air conditioning system or a refrigeration system. 
   The method and apparatus of the invention can assist in the servicing of pressurized systems, such as air conditioning or refrigeration systems. The coupling member includes a self-sealing mechanism that can prevent or reduce refrigerant loss and injury in the event the coupler is accidentally disconnected under pressure. In addition, the coupling member can be constructed so that the control knob opens and closes the service port of the system in less than a complete revolution (i.e., in one half to two thirds of a complete revolution). The coupling member has a short length and small diameter, which can facilitate access to the service port in tight spaces. In addition, the coupling member can engage with the service port of the system using a release sleeve assembly including more than six steel balls (e.g., eight balls). Six or more balls increase stability and grip of the member with the valve. The coupling member can have a length (T) of about 1.6 inches that remains unchanged when the coupling is in the open and closed positions, and a diameter of about 1.1 inches. These dimensions can allow the coupling to mate with service ports in confined locations. The coupling member can be adapted to mate with Society of Automotive Engineers (SAE)-dimensioned ports and can be constructed from metal, such as, for example, brass, steel, stainless steel, or aluminum, for durability. 
   The method and apparatus of the invention can also include a purge feature that can facilitate servicing pressurized systems. The purge feature can be a purge fitting attached to a service device or a purge actuator incorporated into a device such as a coupling member. The purge feature can reduce or eliminate problems related to introducing air into pressurized fluid systems. The purge feature allows air to be vented in a relatively controlled manner while protecting the user from exposure to the fluid in the system. For example, a purge fitting can be attached to a recovery and recycle machine, a refrigerant cylinder, or a manifold gauge set, or a portion thereof. The purge fitting can attach to a standard hose fitting. The purge fitting can be constructed from metal, a plastic, or a composite. The purge feature can allow air to be vented from hoses and other parts of a service device prior to working on the system. The purge feature can prevent air from entering the system. Air can be vented from an air conditioning system service device during servicing by depressing the purge actuator. At the first sound or sign of refrigerant near the purge vent, the purge actuator can be released, stopping flow of the refrigerant nearly instantaneously. The purge feature can improve the safety of servicing a pressurized system. For example, the purge feature can help prevent or reduce release of fluids (e.g., liquids or gases), such as refrigerants, from the system or service device. In addition, the purge feature can be configured to help protect the user from refrigerant freeze and reduce the duration of servicing. 
   Additional features and advantages of the invention will become apparent from the detailed description of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic drawing depicting a sectional view of a coupling member having a purge actuator. 
       FIG. 2  is a schematic drawing depicting a sectional view of a coupling member having a purge actuator and engaged with a port. 
       FIG. 3  is a schematic drawing depicting an exploded view of a coupling member having a purge actuator. 
       FIG. 4  is a schematic drawing depicting an exploded view of a pusher and pin depressor assembly. 
       FIG. 5  is a schematic drawing depicting a sectional view of a coupling member in a valve closed position. 
       FIG. 6  is a schematic drawing depicting a sectional view of a coupling member in a valve open position. 
       FIG. 7  is a schematic drawing depicting a sectional view of a purge fitting in a closed position. 
       FIG. 8  is a schematic drawing depicting a sectional view of a purge fitting in an open position. 
       FIG. 9  is a schematic drawing depicting a view of a purge fitting attached to a service manifold. 
       FIG. 10  is a schematic drawing depicting a view of a service manifold including a purge actuator. 
       FIG. 11  is a schematic drawing depicting a view of a valve core removal tool including a purge actuator. 
   

   DETAILED DESCRIPTION 
   Referring to  FIGS. 1–3 ,  5 , and  6 , coupling member  2  includes body  4 . Body  4  has first end  6  attached to release sleeve assembly  8 . Release sleeve assembly  8  includes adapter  10  which is attached by threads to first end  6 . Alternatively, adapter  10  can be attached to first end  6  by pins, set screws, a snap ring, brazing, soldering, or swaging. O-ring  11  provides a fluid-tight seal between adapter  10  and body  4 . Release sleeve  12  slides over adapter  10 . Retaining ring  14  holds release sleeve  12  over adapter  10 . Release sleeve spring  16  resides between release sleeve  12  and adapter  10  and pushes release sleeve  12  against retaining ring  14 . When pushed against retaining ring  14 , release sleeve  12  holds balls  18  within adapter  10 . Balls  18  are distributed around the circumference of adapter  10 . First end  6  includes orifice  20 , which can receive a service port, which includes a valve, of a pressurized system. Balls  18  engage with the service port when the port is inserted into orifice  20 . O-ring  21  is disposed within orifice  20  and is imbedded in adapter  10  to provide a fluid-tight seal between coupling member  2  and the service port. 
   Body  4  also has a second end  22  having control knob  24 . Second end  22  has a groove  26  into which pins  28  and  30  fit. Pins  28  and  30  affix control knob  24  to body  4  so that control knob  24  can rotate about the longitudinal axis of coupling member  2 . O-ring  32  forms a fluid-tight seal between body  4  and control knob  24 . 
   Control knob  24  has inner threaded surface  34  that contacts outer threaded surface  36  of pusher  40 . Pusher  40  is disposed in interior chamber  42  of body  4 . Interior chamber  42  is defined by inner surface  44  of body  4 . Pusher  40  has valve actuation portion  46  extending toward first end  6  and orifice  20 . Valve actuation portion  46  supports valve detection member  48 . Valve detection member  48  is a ring surrounding valve actuation portion  46  and is slidably disposed on valve actuation portion  46 . Valve detection member  48  is held on valve actuation portion  46  by retaining ring  50 . Spring  52 , also located on valve actuation portion  46  biases valve detection member  48  along valve actuation portion  46  toward retaining ring  50 . 
   Body  4  also includes port  54 , which is in fluid communication with interior chamber  42  and orifice  20 . Pin depressor  56  is located within interior chamber  42  and proximate to port  54 . Pin depressor  56  is fixed to pusher  40  by roll pin  58 . Pin depressor  56  can rotate about roll pin  58 . Referring to  FIG. 4 , pusher  40 , having valve actuation portion  46 , valve detection member  48 , retaining ring  50 , spring  52 , pin depressor  56 , and roll pin  58  form dual-valve opening assembly  60 . 
   In certain embodiments, shown in  FIGS. 2 ,  3 ,  5  and  6 , port  54  includes outlet port  62 . Outlet port  62  can be a 14 mm connector (as shown). The connector can be combined with a 14 mm male port, a 14 mm female port, a ¼ inch male flare port, a ¼ inch female flare port, a ⅜ inch male flare port, a ⅜ inch female flare port, a ½ inch ACME male port, or a ½ inch ACME female port. O-ring  64  provides a fluid-tight seal between outlet port  62  and body  4 . Outlet port  62  includes valve  66  within port  54 . Valve  66  has poppet  68  which opens valve  66  when depressed. Poppet  68  extends toward pin depressor  56 . 
   Referring to  FIGS. 2 ,  3 ,  5  and  6 , coupling member  2  is connected to service port  70 . Service port  70  is inserted into orifice  20 . O-ring  21  forms a fluid-tight seal with service port surface  72 . Service port  70  contains Schrader-type valve  74 . Valve  74  can be a primary seal-type valve. Schrader-type valve  74  has pin  76  which opens the valve when pressed into the valve. Coupling member  2  is configured so that valve  66  operates as a safety valve and does not open unless service port  70  is inserted into orifice  20 . This feature reduces the likelihood or prevents opening the coupling and allowing refrigerant to escape when the coupling member is not connected to the system. This feature also can ensure that the coupling member closes if it is accidentally disconnected while in the open position and can make it easier to connect to a system under pressure. 
   In operation, rotation of control knob  24  moves pusher  40  toward orifice  20  from a valve closed position (shown in  FIG. 5 ) to a valve open position (shown in  FIG. 6 ). When pusher  40  moves from the valve closed position to the valve open position, valve actuation portion  46  contacts pin  76 , depressing it and opening valve  74 . Referring to  FIG. 6 , as pusher  40  moves toward orifice  20 , valve detection member  48  contacts tip  78  of service port  70 . Valve detection member  48  is oriented so that tip  78  prevents further movement of valve detection member  48 . As a result, valve detection member  48  slides along valve actuation portion  46 , compressing spring  52 . As pusher  40  moves and opens valve  74 , pin depressor  56  moves toward and contacts valve detection member  48 . When this contact occurs, pin depressor  56  moves from a first position, shown in  FIG. 5  in which valve  66  is closed and pin depressor  56  is within interior chamber  42 , to a second position, shown in  FIG. 6  in which pin depressor  56  extends partially into port  54 , depressing poppet  68  and opening valve  66 . If service port  70  is not inserted into orifice  20 , then valve detection member  48  will not contact pin depressor  56  and valve  66  will not be opened. 
   Control knob  24  and pusher  40  are threaded so that pusher  40  moves from the valve closed position to the valve open position in less than one complete revolution of the knob, preferably about one-half of a complete revolution of the knob. The external dimensions of the coupling member do not change when in the open or closed position; the control member is not displaced relative to the body. Referring to  FIGS. 5 and 6 , because control knob  24  is attached to body  4  by pins  28  and  30  in groove  26 , the length T of the coupling member does not change when the control member is opened and closed. Preferably, T is less than about 8 inches, more preferably less than about 1.7 inches, and most preferably about 1.6 inches. This feature allows the coupling member to be used in tight spots, since it occupies the same amount of space in the valve open position and the valve closed position. 
   Referring to the embodiment of  FIGS. 1–3 , coupling member  2  includes purge actuator assembly  100 . Purge assembly  100  includes cap  102  and shaft  104  which enters opening  106  in body  4  and extends through chamber  42 . O-ring  108  provides a fluid-tight seal between shaft  104  and body  4 . Shaft  104  extends to pin depressor  56 . Spring  110  biases purge assembly  100  away from body  4 . When purge assembly  100  is pressed inward, shaft  104  moves pin depressor  56 . As shown in  FIG. 2 , this motion will cause pin depressor  56  to contact poppet  68 , opening valve  66 . When outlet port  62  is attached to a pressurized fluid source by a conduit, such as a hose, pressing the purge assembly allows air to be vented from the conduit and from the coupling member as the pressurized fluid moves into the coupling member. 
   The purge feature can be attached to an existing pressurized fluid service device using a purge fitting, or it can be incorporated directly into a service device. Referring to  FIGS. 7 and 8 , purge fitting  200  has body  201 . Body  201  has fluid inlet  202 , fluid outlet  204 , and vent port  206 . Fluid inlet  202  and fluid outlet  204  function interchangeably, depending on the direction of fluid flow through the device. Purge shaft  208  is attached to purge button  210  and extends into body  201 . O-ring  211  is seated on purge shaft  208 . Purge shaft  208  is seated in a recess in plug  212  on the opposite side of body  201 . Plug  212  is sealed to body  201  by o-ring  214 . Plug  212  has an outward threaded surface  216  that engages with inward threaded surface  218  of body  201 . Spring  220  is located along purge shaft  208 . 
   The purge fitting has a closed position, shown in  FIG. 7 , and an open position, shown in  FIG. 8 . Spring  220  biases purge shaft  208  to the closed position. Referring to  FIG. 7 , O-ring  211  provides a fluid-tight seal between purge shaft  208  and body  201 . In the closed position, fluid inlet  202  and fluid outlet  204  are in fluid communication. Referring to  FIG. 8 , when purge button  210  is depressed to open the purge fitting, o-ring  211  separates from body  201 , allowing fluid communication between fluid inlet  202 , fluid outlet  204 , and vent port  206 . When purge button  210  is depressed to that the purge fitting is opened, button  210  covers orifice  222  through which air is vented via vent port  206 . By covering orifice  222  when the purge fitting is opened, button  210  protects the user from direct contact with the fluid if fluid happens to be discharged through vent port  206 . Body  201  is recessed at the position of the purge shaft  208  and o-ring  211  so that the cross-sectional area within body  201  is substantially unchanged when the purge fitting is opened and closed. As a result, fluid communication between fluid inlet  202  and fluid outlet  204  is substantially unrestricted when the purge button is in the open position and the closed position. 
   Inlet  202  and outlet  204  can be configured to mate with R12, R134a, 14 mm, or other fittings for air conditioning or refrigeration service. Referring to  FIG. 9 , purge fittings  200  can be installed in existing service manifold  300 , such as, for example, item M-71A6Q (CPS Products, Inc., Hialeah, Fla.). Purge fittings  200  can be attached between hoses  330  and manifold body  332  so that purge buttons  210  can be accessed at the manifold. Service manifold  300  includes pressure gauges  210  that provide pressure readings within the manifold and knobs  320  that control fluid flow through hoses  330 . 
   Referring to  FIGS. 10 and 11 , a purge feature can be incorporated directly into a service device, such as service manifold  301  or valve core removal tool  400 . Referring to  FIG. 10 , a purge device can be incorporated into manifold  302 , having purge buttons  210  exposed for easy access. The pressure gauges  310 , knobs  320  and hoses  330  of the service manifold remain unchanged. Referring to  FIG. 11 , valve core removal tool  400  includes a purge device, including purge button  210 . The purge device is installed in body  402  Valve core removal tool  400  has service end  404 , which attaches to a male service port (e.g., an R134a port), and service hose port  406 , to which a service hose attaches. Air is vented from the service hose and the body when purge button  210  is pressed. Valve core removal tool  400  also has control knob  408  attached to body  402  that opens and closes a valve core body plug within the tool. Retraction shaft  410  is attached to body  402  by fitting  412 , which seals shaft  410  to body  402 . A valve core removal tool that does not include a purge feature can be modified to include a purge feature. Suitable valve core removal tools which can be modified include part CD3900 (C&amp;D Valve Manufacturing, Oklahoma City, Okla.). 
   While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention. 
   The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.