Abstract:
A system for preparing a refrigerant sample for analysis including a pressure regulator assembly including a pressure regulator and provisions for heating a refrigerant sample contained within an interior region of the pressure regulator. The pressure regulator defines an inlet through which the refrigerant sample is delivered and an outlet through which the refrigerant sample is expelled. The system also includes a filter assembly having an inlet that is fluidly connected to the outlet of the pressure regulator to receive the vaporized refrigerant sample from the pressure regulator, at least one filter for removing contaminants from the refrigerant sample, and an outlet that is configured to be coupled to a refrigerant analysis system for analyzing a composition of the refrigerant sample.

Description:
FIELD OF THE INVENTION 
     The disclosed invention relates to a system and method for preparing a refrigerant sample for analysis. 
     BACKGROUND OF THE INVENTION 
     A key element of the responsible use and stewardship of refrigerants is the recovery, recycling and reclamation of used refrigerants so that they can be reprocessed for further commercial use or destroyed. It has become standard practice in the refrigeration system service industry to recover and reclaim refrigerant for later reuse, rather than merely to vent such refrigerant into the atmosphere, as had been common practice in the past. Refrigerants can be recovered, recycled and reclaimed from many systems, such as mobile air conditioners, stationary air conditioners and refrigeration systems, for example. The recovered refrigerant is then transported to a facility for reclamation. 
     The reclamation process typically encompasses an initial chemical analysis of a sample of the recovered refrigerant in an effort to identify the composition of the recovered refrigerant that is to be reclaimed. The following steps are commonly performed to prepare the refrigerant sample for analysis: (1) drawing a sample of liquid refrigerant, (2) injecting the sample into a sample bomb, (3) vaporizing the sample in the bomb, (4) filtering the vaporized sample to remove contaminants, such as lubricants, water and metallic particles, and (5) manually introducing the filtered sample into an analytical instrument for analysis, such as mass spectroscopy and gas chromatography. Contaminants, such as oil or other lubricants are filtered from the vaporized sample in step 4 because those contaminants could impair the chromatography process. 
     The foregoing preparation steps are time consuming, typically consuming 90 minutes or more, and, for that reason, only a small fraction of recovered refrigerant may be analyzed. In order to comply with ever-increasing regulatory demands it has become necessary to conduct a more comprehensive analysis of the recovered refrigerant that is to be reclaimed. Such regulatory demands are defined in Air-conditioning, Heating and Refrigeration Institute (AHRI) Standard No. 700-2006. Thus, there is a need in the industry for a refrigerant sample preparation system that can be employed to more rapidly prepare recovered refrigerant for analysis. 
     SUMMARY OF THE INVENTION 
     According to an aspect of the invention, a system for preparing a refrigerant sample for analysis is provided. The system comprises a pressure regulator assembly including a pressure regulator and means for heating a refrigerant sample contained within an interior region of the pressure regulator. The pressure regulator defines an inlet through which the refrigerant sample is delivered and an outlet through which the refrigerant sample is expelled. The system further comprises a filter assembly having an inlet that is fluidly connected to the outlet of the pressure regulator to receive the vaporized refrigerant sample from the pressure regulator, at least one filter for removing contaminants from the refrigerant sample, and an outlet that is configured to be coupled to a refrigerant analysis system for analyzing a composition of the refrigerant sample. 
     According to another aspect of the invention, a method for preparing a refrigerant sample for analysis is provided. The method includes the step of introducing a refrigerant sample through an inlet of a pressure regulator and into an interior region of the pressure regulator. The refrigerant sample within the interior region of the pressure regulator is heated to vaporize the refrigerant sample. The vaporized refrigerant sample is distributed through a filter to remove contaminants in the refrigerant sample. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is best understood from the following detailed description when read in connection with the accompanying drawing. Included in the drawing are the following figures: 
         FIG. 1  is a schematic view of refrigerant sample preparation system according to one exemplary embodiment of the invention; 
         FIG. 2  is a top plan view of a heated pressure regulator of the system of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of the heated pressure regulator of  FIG. 2  taken along the lines  3 - 3 ; 
         FIG. 4  is a cross-sectional view of the heated pressure regulator of  FIG. 2  taken along the lines  4 - 4 ; and 
         FIG. 5  is a cross-sectional view of the filter assembly of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention is best understood from the following detailed description when read in connection with the accompanying drawing, which shows exemplary embodiments of the invention selected for illustrative purposes. The invention will be illustrated with reference to the figures. Such figures are intended to be illustrative rather than limiting and are included herewith to facilitate the explanation of the present invention. In the various embodiments like item numbers represent substantially similar features. 
       FIG. 1  is a schematic view of refrigerant sample preparation system according to one exemplary embodiment of the invention. The refrigerant sample preparation system, which may be referred to hereinafter as a system, is denoted by the numeral ‘ 10 .’ According to one exemplary embodiment of the invention, the system  10  generally includes a sample container  11  filled with a refrigerant sample, a heated pressure regulator assembly  12  that is fluidly coupled to sample container  11  for heating a refrigerant sample, a filter assembly  14  having an inlet port  21  that is fluidly coupled to pressure regulator assembly  12  via conduit  15  for filtering the heated refrigerant sample, and a conduit system  16  that is fluidly coupled to filter assembly  14  to provide a passageway for venting and vacuuming of system  10 . A conduit  17  is fluidly coupled between an outlet port  18  of filter assembly  14  and an analytical instrument  20 . The analytical instrument  20  may be a mass spectrometer, a gas chromatograph, or a flame ionization detector, for example. According to one aspect of the invention, analytical instrument  20  is a mass spectrometer and a gas chromatograph. 
     The conduit system  16  comprises a series of interconnected fluid-carrying pipes  13  and discrete valves  19   a - 19   e  mounted to fluid-carrying pipes  13 . The conduit system  16  is fluidly coupled to a vacuum source  22 , which is configured to evacuate filter assembly  14  and pressure regulator assembly  12 . The conduit system  16  is also fluidly coupled to a venting container  24  for collecting refrigerant sample that is utilized for flushing filter assembly  14  and regulator assembly  12 . The venting container  24  may be a refrigerant reclamation system, for example. A series of discrete valves  19   a - 19   e , which are maintained in either an open position or a closed position, are provided on conduit system  16  to facilitate vacuuming and venting operations of filter assembly  14  and pressure regulator assembly  12 . The discrete valves  19   a - 19   e  normally remain in a closed position to prohibit the passage of fluid thereacross. During a vacuum stage, however, discrete valves  19   a ,  19   b ,  19   c  and  19   e  are open and valve  19   d  is closed, and during a venting stage, discrete valves  19   a - 19   d  are open and valve  19   e  is closed. The valves  19   a - 19   e  may be automated by processor  23  or operated manually. 
     Although not shown, another discrete valve may be provided on sample container  11  or on the conduit between sample container  11  and regulator assembly  12  to prevent the passage of refrigerant into regulator assembly  12 . Another discrete valve may also be provided on analytical instrument  20  or on conduit  17  to prevent the delivery of refrigerant into instrument  20 . 
     Referring now to  FIGS. 2-4 ,  FIG. 2  depicts a top plan view of a heated pressure is regulator assembly  12  of  FIG. 1 , and  FIGS. 3 and 4  depict cross-sectional views of heated pressure regulator assembly  12  of  FIG. 2  taken along the lines  3 - 3  and  4 - 4 , respectively. The heated pressure regulator assembly  12  includes a pressure regulator  30  that is at least partially encased within a heated sleeve  32 . The pressure regulator  30  includes an inlet port  40  through which refrigerant sample is distributed into the interior of pressure regulator  30 , an outlet port  42  through which the refrigerant sample is expelled from the interior of pressure regulator  30 , a valve (not shown) for selectively permitting the passage of the refrigerant sample between inlet port  40  and outlet port  42 , and a knob  43  for adjusting the pressure setting of pressure regulator  30 . Operation of a pressure regulator is understood by those skilled in the art. A suitable pressure regulator may be offered by the Tescom Corporation of McKinney, Tex., USA. 
     The heated sleeve  32  is generally cylindrical and is composed of a conductive material, such as aluminum, for example. The sleeve  32  is heated by two heating elements  35 . As best shown in  FIG. 3 , thermal contact is established between the revolved interior surface of heated sleeve  32  and the revolved exterior surface of regulator  30  at interface  36  such that thermal energy is transferred from sleeve  32  to regulator  30 . The pressure regulator  30  is also composed of a conductive material such that thermal energy is transferred from the exterior surface of pressure regulator  30  to refrigerant that is contained within pressure regulator  30 . The sleeve  32  at least partially encapsulates regulator  30  to evenly distribute heat across the entire revolved surface of pressure regulator  30 . According to this exemplary embodiment, sleeve  32  extends around the entire circumference of pressure regulator  30 , with the exception of two apertures  33  that are disposed at the lower end of sleeve  32  to accommodate inlet port  40  and outlet port  42  of regulator  30 . 
     Two bores  34  (two shown) are formed in heated sleeve  32 , wherein each bore  34  accommodates a single heating element  35 . The heating elements  35  are positioned on opposing sides of heated sleeve  32  (see  FIG. 2 ), and extend a substantial portion of the length dimension of heated sleeve  32  (see  FIG. 4 ) to uniformly heat the surfaces of pressure regulator  30 , as well as the refrigerant sample that is contained within regulator  30 , to a pre-determined temperature. The heated sleeve  32  may accommodate any number of heating elements and is not limited to the embodiment shown and described herein. A thermocouple  38  is mounted to the top exterior surface of heated sleeve  32 . The thermocouple  38  is configured to measure a temperature of sleeve  32  and transmit that temperature measurement to a computer processor  23  of system  10 . The processor  23  controls the amount of heat emitted by heating element  35  as a function of the temperature is measurement recorded by thermocouple  38 . 
       FIG. 5  depicts a cross-sectional view of filter assembly  14  of  FIG. 1 . The filter assembly  14  generally includes a housing  50  defining an interior fluid passageway within which three coalescing filter cartridge assemblies  53   a - 53   c  are positioned in series, an inlet port  21  coupled to housing  50  through which the heated refrigerant sample is delivered into the fluid passageway, and an outlet port  18  coupled to housing  50  through which the filtered and heated refrigerant sample is expelled. In operation, heated refrigerant sample is delivered through inlet port  21 , through filter cartridge assemblies  53   a - 53   c  in sequential order and expelled through outlet port  18 . In  FIG. 5 , the flow path of the refrigerant sample through the filter assembly  14  is indicated by arrows. 
     The housing  50  is a machined block of aluminum, for example. Three openings  55   a - 55   c  are defined in housing  50 . One bore  67  is defined in a wall of housing  50  between openings  55   a  and  55   b , and another bore  69  is defined in a wall of housing  50  between openings  55   b  and  55   c . One coalescing filter cartridge assembly  53   a - 53   c  is positioned within each opening  55   a - 55   c , respectively. Each coalescing filter cartridge assembly  53   a - 53   c  includes a coalescing filter  56   a - 56   c  mounted to a cartridge  57   a - 57   c , respectively. An annular shoulder  59  is provided on the bottom end of each cartridge  57   a - 57   c  for mounting a coalescing filter  56   a - 56   c , respectively. The filters  56   a - 56   c  may be adhered or merely positioned on annular shoulder  59  of cartridges  57   a - 57   c , as shown. The coalescing filters  56   a - 56   c  have a substantially annular shape. The term ‘coalescing’ denotes the separation of liquid aerosols and droplets from a gas stream. The coalescing filters  56   a - 56   c  have a borosilicate glass filter element (fiber), manufactured (for example) by the Parker Hannifin Corporation. 
     Each cartridge  57   a - 57   c  is mounted to cover  60   a - 60   c , and each cover  60   a - 60   c  is mounted to housing  50  by two fasteners  62 , respectively. Each cover  60   a - 60   c  includes a fluid passageway  64  for delivering fluid to a coalescing filter cartridge assembly  53   a - 53   c . More particularly, fluid passageway  64  of cover  60   a  fluidly connects inlet port  21  with fluid passageway  58  of cartridge  57   a . The fluid passageway  64  of cover  60   b  fluidly connects bore  67  with fluid passageway  58  of cartridge  57   b . The fluid passageway  64  of cover  60   c  fluidly connects bore  69  with fluid passageway  58  of cartridge  57   c.    
     Each cartridge  57   a - 57   c  includes a substantially cylindrical body defining an interior fluid passageway  58  extending from one inlet  63  and a plurality of outlets  65  (four shown). In each coalescing filter cartridge assembly  53   a - 53   c , an annular space  66  is defined between the exterior surface of cartridge  57   a - 57   c  and the interior surface of filter  56   a - 56   c . In operation, heated refrigerant is directed from outlets  65  of cartridges  57   a - 57   c  into annular space  66 . Another annular space  68  is defined between the exterior surface of filter  56   a  and the surface of opening  55   a  of each coalescing filter cartridge assembly  53   a - 53   c . In operation, heated refrigerant passes through filter  56   a - 56   c  and collects in annular space  68 . 
     An outlet fitting  70   a - 70   c  is fixed to housing  50  and is fluidly connected to the bottom end of opening  55   a - 55   c , respectively. Each outlet fitting  70   a - 70   c  is fluidly coupled to a discrete valve  19   a - 19   c , respectively (see  FIG. 1 ). In an open position of one or more discrete valves  19   a - 19   c , fluid is expelled from filter assembly  14  and is distributed through conduit system  16 . Conversely, in a closed position of all three discrete valves  19   a - 19   c , fluid is prevented from entering conduit system  16 . 
     Referring now to the operation of refrigerant sample preparation system  10  with reference to  FIGS. 1 and 5 , at start-up of system  10 , heating elements  35  are activated and discrete valves  19   a - 19   e  are closed. Once regulator assembly  12  reaches a pre-determined temperature, as measured by thermocouple  38 , the liquid-phase oil-laden refrigerant is directed from container  11  into regulator assembly  12 . Once the liquid-phase oil-laden refrigerant is heated within regulator assembly  12  to a pre-determined temperature, as measured by thermocouple  38 , the refrigerant undergoes a phase change from a liquid state to a vapor state. It should be understood that heating the refrigerant increases its flow rate through system  10 , which increases the speed of the refrigerant sample preparation process. Once the refrigerant reaches a vapor state, the oil-laden vapor-phase refrigerant is distributed through filter assembly  14 . More particularly, the heated vapor-phase refrigerant is distributed through inlet port  21  of filter assembly  14  and into fluid passageway  64  of cover  60   a . The heated refrigerant enters inlet  63  of fluid passageway  58  of cartridge  57   a  and exits through outlets  65  of fluid passageway  58  of cartridge  57   a  into annular space  66  of coalescing filter cartridge assembly  53   a . The heated refrigerant flows across filter  56   a  and enters annular space  68  of coalescing filter cartridge assembly  53   a . This represents the first pass of the refrigerant through a filter. Because discrete valve  19   a  is maintained in a closed position, the refrigerant is urged upwards through bore  67  of housing  50 . 
     The once-filtered, heated refrigerant then enters fluid passageway  64  of cover  60   b , travels through inlet  63  of fluid passageway  58  of cartridge  57   b  and exits through outlets  65  of fluid passageway  58  of cartridge  57   b  into annular space  66  of coalescing filter cartridge assembly  53   b . The heated refrigerant flows across filter  56   b  and enters annular space  68  of coalescing filter cartridge assembly  53   b . This represents the second pass of the refrigerant through a filter. Because discrete valve  19   b  is maintained in a closed position, the refrigerant is urged upwards through bore  69  of housing  50 . 
     The twice-filtered, heated refrigerant then enters fluid passageway  64  of cover  60   c , travels through inlet  63  of fluid passageway  58  of cartridge  57   c  and exits through outlets  65  of fluid passageway  58  of cartridge  57   c  into annular space  66  of coalescing filter cartridge assembly  53   c . The heated refrigerant flows across filter  56   c  and enters annular space  68  of coalescing filter cartridge assembly  53   c . This represents the third pass of the refrigerant through a filter. By the third pass, contaminants, such as oil or other lubricants, are substantially removed from the vapor-phase refrigerant. Because discrete valve  19   c  is maintained in a closed position, the refrigerant is urged upwards through outlet port  18  of filter assembly  14  and into conduit  17 . The filtered refrigerant is then distributed into analytical instrument  20  (see  FIG. 1 ) for analysis. 
     Once analysis of the refrigerant sample is complete, the system is readied for another dose of a refrigerant sample (referred to hereinafter as the second refrigerant sample or the second dose). Prior to injecting system  10  with the second dose of refrigerant, system  10  is vacuumed, flushed and vented to remove any remainder of the previous refrigerant sample. More particularly, to prepare the system for the second dose, the contents of filter assembly  14  and regulator assembly  12  are first evacuated to remove the bulk of the previous refrigerant sample. In a vacuuming procedure, discrete valves  19   a - 19   c  and  19   e  are opened, discrete valve  19   d  is closed, a discrete valve (not shown) positioned between container  11  and regulator assembly  12  is closed, and vacuum source  22  is activated. The vacuum source  22  draws a vacuum through conduit assembly  16 . The contents within filter assembly  14  and regulator assembly  12  are evacuated through conduit assembly  16 . The discrete valves  19   a - 19   c  may be opened either simultaneously or sequentially while vacuum source  22  is activated. 
     Thereafter, system  10  and analytical instrument  20  are flushed with the second dose to remove any residual of the previous refrigerant sample. To flush system  10  and analytical instrument  20 , discrete valves  19   a - 19   e  are closed, and a limited quantity of the second dose is distributed through system  10  and analytical instrument  20 . Thereafter, system  10  and analytical instrument  20  are vented by opening discrete valves  19   a - 19   d . Venting system  10  and analytical instrument  20  exposes system  10  and analytical instrument  20  to atmospheric pressure to obtain a consistent volume of the second dose in analytical instrument  20 . The second refrigerant dose exhausts into venting container  24 . After the final venting step, the system  10  and analytical instrument  20  are now sufficiently free of the previous refrigerant sample and ready to analyze the remainder of the second dose of refrigerant. The remainder of the second dose is distributed through system  10  into analytical instrument  20 . This process may be repeated continuously. 
     While preferred embodiments of the invention have been described herein, it will be understood that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those skilled in the art without departing from the spirit of the invention. For example, the system disclosed herein is not limited to distributing refrigerant. The system may also be configured to distribute liquids, gases, flammable or non-flammable fluids, water, industrial mixtures, hydrocarbon mixtures, reactor gas mixtures or any other fluid. It is intended that the appended claims cover all such variations as fall within the spirit and scope of the invention.