Abstract:
Assaying of liquid samples of refrigerant to determine their composition utilizing refractive index techniques. The sampling may be done with the use of extractors which remove refrigerant gases from refrigerant machines, and clean and dry the sample before it is assayed.

Description:
FIELD OF THE INVENTION 
     Obtaining from an existing refrigeration machine a representative sample of its refrigerant fluid in the liquid phase, and assaying the sample using refractive index techniques. 
     BACKGROUND OF THE INVENTION 
     The refrigerating cycle which mechanically compresses gaseous refrigerant into the liquid phase, and cools surroundings when the liquid is vaporized is famous and needs no explanation here. Halogenated carbon compounds such as CFC&#39;s, while ideal for refrigerant purposes, have proved to be a profound risk to the environment. For this reason their release into the atmosphere is generally forbidden. 
     The places the owner of a refrigerant system, especially of large air conditioning systems in a quandary. He can, of course, hire a collection service to remove all of the gases and replace them with others of known composition, but this is an economic cost which should be avoided if possible. 
     If a complete recharge is to be avoided by adding make-up gas, the question is what kind of gas to add to the system. There are many kinds of refrigerant gases available, and the owner has no reliable way to know what is actually there especially in older systems. It is unwise to mix unknown gases. A device, suitably portable, is needed to learn the constituent gases in the system being serviced. 
     Systems have been proposed to assay the contents of a system, but have not provided a convenient and sufficiently accurate sample preparation and assaying technique. It is an object to provide such a system and method. 
     A known system to recover refrigerant gas for later disposal is shown in applicant&#39;s U.S. Pat. No. 6,620,372, issued Jul. 17, 2001. While it can remove the gases, it is not adapted to assay them, and especially not with the use of a refractive index analyzer. 
     BRIEF DESCRIPTION OF THE INVENTION 
     A sampling and assaying system according to this invention receives refrigerant fluid from a machine whose fluid is to be assayed. The fluid is preferably received in its liquid phase. If not, it must be converted to the liquid phase before being analyzed. After the fluid enters this system, it is filtered and de-acidified. Thereafter it passes through an oil separator, another filter, and a drier. At this point, the undesirable contaminants will have been removed. A pump removes the “purified” refrigerant, which now may be removed from the system for assay purposes. 
     According to this invention a refractive index analyzer is disposed between two selector valves, which can be set to permit the liquid to enter the analyzer. Alternatively, they can be set to direct the system fluid to a recovery tank. 
     Accordingly, this system can be utilized as a collector from the refrigeration machine for disposal elsewhere, or as an analyzer for successive analytical runs. 
     The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings, in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1, the only figure, is a schematic drawing showing the circuitry of this invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Inlet pipe  20  from a machine (not shown) whose refrigerant is to assayed is separably joined to an inlet fitting  21  of the system of this invention. An on-off valve  22  is connected to a hose  23  from the fitting and to a hose  24 , thereby to control entry of fluid into the system. 
     A filter/deacidifier  25  is connected to hose  24 . It is a conventional cartridge type which removes particulate matter, and neutralizes acids of the type customarily found in used refrigerants. 
     At this point, Burke U.S. Pat. No. 6,260,372 is incorporated by reference herein in its entirety for its showing of useful elements of this system, upstream from the analyzer. The reader will notice the similarities to FIG. 3 of that patent. 
     A bypass conduit  27  is connected across the filter de-acidifier. It includes shut-off valve  28 . This arrangement, coupled with protective valves, enables the filter/acidifier to be by-passed if desired. 
     A liquid/vapor valve  31  is connected at the downstream end of the filter/de-acidifier and the by-pass at a T joint  32 . The liquid-vapor valve is adapted to pass either gas or liquid. It is further connected to the inlet of a sight glass  35 . The sight glass enables the viewer to ascertain whether liquid or gas is flowing through the system at this point. 
     A conduit  37  receives fluid from the sight glass and conveys it to a tank-type oil separator  40 . Oil settles to the bottom of the tank from which it is withdrawn through outlet  41 , passes through a flow control  42  and enters an oil recovery tank  43 . An off-on oil drain valve  44  controls flow of oil to tank  43 . 
     Refrigerant fluid in whatever phase is withdrawn from the top of the oil separator through outlet  50 . It flows through conduit  51  to two branches  52 ,  53 , each of which enters a respective filter/dryer tank  54 ,  55 . 
     Outlet conduits  56 ,  57  are joined to a discharge conduit  58 . Conduit  58  is connected to an off-on discharge valve  60 . This is the ultimate control valve for the active system. 
     Inlet  65  of a pressure pump  66  is connected to the outlet end of the discharge valve. When in operation, it withdraws fluid from the upstream system and pressurizes it so as to be certain that the fluid is in the liquid phase. 
     A refractive index analyzer  70  of any suitable type is plumbed into this system downstream from the pump. It is intended to receive sample material for analysis. After the sample has been analyzed, it must still remain captive. For this purpose a recovery tank  71  is provided. This recovery tank may also be used when the entire system is to be purged, as will become evident. 
     A first selector valve  75  has an inlet  76  connected to the outlet of the pump. It has two selectible ports  77 ,  78 . The first port  77  is connected to the inlet of the analyzer. The second port  78  is connected to the inlet port  80  of the recovery tank through a shut-off valve  81 . 
     A second selector valve  82  has an inlet port  83  and selectible outlet ports  84 ,  85 . It also has a shut-off condition in which no flow is allowed. Port  84  is connected to the recovery tank inlet. Port  85  is optional. When used, it is connected to an optional return line  86 , which extends to the inlet of the oil separator. As will be seen, the return line is optional, and in the simplest embodiment, valve  82  has only two settings, one to close the valve and the other to permit flow to the recovery tank. 
     The operation of this system is straight forward. With appropriate valves open or closed, and the pump in operation, a liquid sample is collected in the analyzer and analyzed. When analysis is completed, the sample is discharged to the recovery tank. Alternatively it may be returned to the oil separator, in which event it will remain in the system. The assay will be repeated for sequential analyses on the same system, or will later be used on other machines. In that event, the device will be purged of the residue gases (which will be caught in the recovery tank), or back to the refrigeration machine system from which it originally came from before the next sample is secured. 
     This invention is not to be limited by the embodiment shown in the drawing and described in the description, which is given by way of example and not of limitation, but only in accordance with the scope of the appended claims.