Abstract:
An automatic refrigerant handling apparatus has a compressor pump for withdrawing a refrigerant from an associated refrigeration system to be serviced, a condenser for liquefying the refrigerant and a storage vessel for storing the recovered refrigerant, the compressor pump also being capable of evacuating the refrigeration system to a first refrigeration system pressure. The apparatus has a connection jack for receiving a connector of an associated optional vacuum pump, the connector including a jumper which interconnects two terminals on the jack when the vacuum pump is connected so that the control circuitry of the apparatus can recognize the presence of the vacuum pump, whereupon the program routine of the control processor utilizes the vacuum pump instead of the compressor pump to draw a vacuum on the associated refrigeration system.

Description:
RELATED APPLICATION 
     This application claims the benefit of the filing date of U.S. provisional application No. 60/213,491, filed Jun. 23, 2000. 
    
    
     BACKGROUND 
     This application relates to refrigerant handling systems and, in particular, to systems for automatically recycling refrigerant from the air conditioning systems of automotive vehicles. 
     Typically, automotive air conditioning service systems are designed to recover refrigerant from the vehicle air conditioning system, remove impurities therefrom and recycle the conditioned refrigerant back to the vehicle after servicing of the air conditioner is complete, so as to minimize venting of refrigerant to atmosphere. Such service systems commonly include a compressor for withdrawing refrigerant in vapor form from the vehicle and compressing it, a condenser for liquefying the compressed vapor, a storage vessel for storing the recovered refrigerant and a vacuum pump for drawing a vacuum on the automotive air-conditioning system prior to recharging recycled refrigerant thereto. 
     In some prior refrigerant recycling systems there is no vacuum pump. Rather, the compressor is utilized as both a compressor and as a pump for drawing a vacuum on the automotive refrigeration system. This reduces the cost and complexity of the system, but also reduces the performance somewhat, since the compressor pump is not capable of drawing a vacuum to as low a refrigeration system pressure as could be achieved with a separate vacuum pump. While it is possible in such recycling systems to retrofit the system with a vacuum pump in order to improve performance, this is a relatively complicated procedure and would normally require a technician from the manufacturer to perform the installation at substantial cost to the customer. 
     SUMMARY 
     This application discloses a refrigerant handling apparatus which avoids the disadvantages of prior apparatuses while affording additional structural and operating advantages. 
     An important aspect is the provision of an automatic refrigerant handling apparatus which permits simple installation of an optional device by a user without the need for professional technical assistance. 
     Another aspect is the provision of an apparatus of the type set forth which includes a processor operating under stored program control and which automatically recognizes the presence of the optional device to alter the operation of the apparatus accordingly. 
     A still further aspect is the provision of an apparatus of the type set forth, wherein the optional device is a vacuum pump. 
     Yet another aspect is the provision of a method of utilizing the apparatus of the type set forth. 
     Certain ones of these and other aspects may be attained by providing an automatic refrigerant handling apparatus comprising: a compressor pump having a suction port adapted to be coupled to an associated refrigeration system to be serviced and a discharge port, a condenser coupled to the discharge port, a refrigerant storage vessel coupled to the condenser, control circuitry including a processor operating under control of a stored program and coupled to the compressor pump for controlling operation thereof in accordance with a predetermined procedure for recycling refrigerant from the refrigeration system, and a connection jack connected to the control circuitry and adapted to mateably receive a connector of an associated optional device, the control circuitry including a sensing circuit for detecting connection of the connector to the jack, the stored program including a routine responsive to the sensing circuit for altering the predetermined procedure to utilize the optional device if connection of the connector to the jack is detected. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For the purpose of facilitating an understanding of the subject matter sought to be protected, there are illustrated in the accompanying drawings embodiments thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated. 
     FIG. 1 is a partially functional block and partially schematic diagram of a refrigerant handling apparatus; 
     FIG. 2 is a fluidic schematic diagram of the apparatus of FIG. 1; 
     FIG. 3 is a flow diagram of the main program loop of a software program for controlling the operation of the processor of the system of FIG. 1; and 
     FIG. 4 is a flow diagram of a routine of the software program. 
    
    
     DETAILED DESCRIPTION 
     Referring to FIGS. 1 and 2, there is illustrated a refrigerant recycling system, generally designated by the numeral  10 , which is, for the most part, a type commercially available from Snap-on Diagnostics under the designation “KoolKare.” Accordingly, only so much of the recycling system  10  as is necessary for an understanding of the present invention is described herein. Referring to FIG. 1, the system  10  includes an AC power circuit  11  provided with a three-prong plug  12  for connection to a standard AC supply. The AC power circuit  11  is connected to a power supply circuit  13 , which provides suitable DC voltage to processing and control circuits  15 , which include a processor  16  operating under stored program control. The AC power circuit  11  has a ground line  17 , a neutral line  18  and a “hot” line  19  in standard fashion, respectively connected to corresponding terminals of a five-terminal connection jack  20 , which is mounted at a conveniently accessible location on the system housing. The hot line  19  is connected to the connection jack  20  through a relay  21 , operating under control of the processing and control circuits  15 . The other two terminals of the connection jack  20  are, respectively, connected to one end of sense lines  22  and  23 , the opposite ends of which are respectively connected to terminals of a plug  24  which is mateably engageable with a jack  25  of the processing and control circuits  15 , the jack  25  in turn being connected to the processor  16 . The sense lines  22  and  23  cooperate with the processor to form a sensing circuit. 
     The recycling system  10  includes an optional vacuum pump  26  having three power lines connected to corresponding terminals of a connector plug  27  which is adapted to be plugged into the connection jack  20  for electrically connecting the vacuum pump to the recycling system  10  and, more specifically, for connecting to lines  17 - 19 . Two terminals of the plug  27  respectively connect to, and are interconnected by, a jumper  28  on the plug  27 . While the plug  27  is shown as a 5-terminal plug, since only 5 terminals are used, it may have a larger number of terminals to permit spacing between primary (line voltage) and secondary (low voltage) terminals. 
     Referring to FIG. 2, the recycling system  10  is adapted to be connected to the air-conditioning system of an automotive vehicle, as at  30 , the connection  30  being coupled through a suitable filter and a vacuum solenoid valve  31  to an oil separator  32  for removing oil from the refrigerant, the output of the oil separator  32  in turn being connected to a vacuum switch  33  and, through an oil separator solenoid valve  34 , to a master filter/dryer  35 , the output of which is connected through a manifold  36  to the suction port of a compressor/pump  37 . The discharge of the compressor pump  37  is coupled to the input of an oil separator/reservoir  38 . The system  10  is also provided with a low pressure cutoff switch  41  connected to the input of the oil separator solenoid  34  and a high pressure cutoff switch  42  connected to the output of the oil separator reservoir  38 . The output of the oil separator/reservoir  38  is also connected through a vent solenoid valve  43  to a vent line  44 . A process port of the compressor/pump  37  is connected through a solenoid valve  45  to a return port of the oil separator/reservoir  38 . The output of the condenser  40  is connected through a moisture indicator  46  and a liquid solenoid valve  47  to the Input of a refrigerant recovery tank  50  through suitable anti-blowback valves. The input of the tank  50  is also connected through a purge solenoid valve  51  and an air filter  52  in a purge line, and is also connected to a purge transducer  53 . 
     The refrigerant recovery tank  50  has a liquid outlet coupled through a filter and suitable anti-blowback valves, and then through a charge solenoid valve  55  and a check valve  56  to the automotive connection point  30 . The output of the oil separator  32  is connected through a filter bypass solenoid valve  58  to a vacuum conduit  57 , the other end of which is normally connected to the manifold  36 . 
     The vacuum pump  26  has a suction port and an exhaust port. In order to install the vacuum pump  26  in the recycling system  10 , a cap or plug  29  is removed from the suction port of the vacuum pump  26 , the lower end of the vacuum conduit  57  is disconnected from the manifold  36  and reconnected to the suction port of the vacuum pump  26 , and the plug  29  is then installed on the port of the manifold  36  from which the vacuum line  57  was just disconnected, resulting in the arrangement illustrated in FIG.  2 . The discharge port of the vacuum pump  26  is vented to atmosphere. The electrical plug  27  of the vacuum pump  26  is then plugged into the socket  20  of the recycling system  10  (see FIG.  1 ). A suitable mount (not shown) is provided on the housing of the recycling system  10  to facilitate supporting of the vacuum pump  26  on the housing in a position where it can be conveniently connected to the pneumatic circuitry of the recycling system  10  and to the electrical circuitry thereof. 
     It will be appreciated that the recycling system  10  can be operated in a number of different modes, most of which are not germane to the subject matter of this application and, therefore, will not be described herein. In operation, when the vacuum pump  26  is installed on the recycling system  10 , as indicated in FIGS. I and  2 , its presence will be detected by the processor  16  by reason of the fact that the sense lines  22  and  23  are interconnected by the jumper  28  on the vacuum pump plug  27 . The program which controls the operation of the processor  16  includes a routine responsive to the sensing circuit of which the sense lines  22  and  23  form a part, to control the operation of the system  10  . 
     Referring to FIG. 3, there is illustrated a flow chart for a portion of the main program loop of the program for the processor  16 , this portion being designated  60 . In this portion of the loop, the program checks at  61  to see if a vacuum pump is connected, by monitoring the sensing circuit. If a vacuum pump is connected, the program then sets a vacuum-detect variable at  62  and, if it is not connected, it clears the vacuum detect variable at  63  and proceeds to the remainder of the loop. The program operates in a normal manner until the operator signals that a vacuum is to be pulled on the air-conditioning system of the vehicle being serviced. At this point the program enters a vacuum routine  65 , illustrated in FIG.  4 . The routine first checks at  66  to see if a vacuum is to be pulled. If not, it exists the routine and returns to the main loop. If a vacuum is to be pulled, the program next checks at  67  to see if the vacuum detect variable is set (FIG. 3) signifying that the vacuum pump  26  is installed. If it is not, the routine then moves to  68  to open the oil solenoid valve  45  and then runs the compressor/pump  37  for about five seconds to remove from the oil separator  38  any oil which might be accumulated therein. Next, the program, at  69 , opens the vacuum solenoid valve  31 , the filter bypass solenoid valve  58  and the vent solenoid valve  43  for drawing a vacuum on the refrigeration system using the compressor/pump  37 . Then, at  70 , it turns on the compressor  37  to draw a vacuum. 
     If, at  67 , the vacuum pump is installed, the routine then, at  71 , opens the vacuum solenoid valve  31  and the filter bypass solenoid valve  58  and closes all other solenoid valves, for drawing a vacuum using the vacuum pump  26  and then, at  72  turns on the vacuum pump for drawing vacuum. 
     The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the broader aspects of applicants&#39; 0  contribution. The actual scope of the protection sought is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.