Abstract:
A portable fuel dilution meter and method includes a plurality of sample bottles each with a lid securable thereto and an absorbent material in the bottle. A housing includes a sample bottle receptacle and a hinged head unit over the receptacle including at least a first needle piercing the lid of a sample bottle loaded into the housing receptacle and extending into the headspace of the sample bottle when the head is closed. A vapor sensor is fluidly coupled to the first needle for analyzing vapors in the headspace of the sample bottle.

Description:
FIELD OF THE INVENTION 
     The subject invention relates to vapor sensing devices and fuel dilution meters. 
     BACKGROUND OF THE INVENTION 
     Vapor sensing devices using a surface acoustic wave (SAW) sensor are known. See for example U.S. Pat. Nos. 5,469,369, and 5,465,608 incorporated herein by this reference. 
     Such devices can be used in systems to detect the presence of a contaminant (e.g., fuel, moisture, or a coolant) in oil (e.g., engine oil, hydraulic oil, or the like). The fuel dilution meter (Q600) product available from Spectro Scientific, Inc. (Chelmsford, Mass.) is an example of such a system. 
     In that system, a rather large bottle is filled % full with oil and inserted into the machine. A tube is inserted into the bottle. Vapors in the “headspace” of the bottle above the oil are drawn via the tube and a pump over a SAW sensor module which detects the presence of contaminant vapors. 
     But, if the bottle is filled too full, liquid oil can be drawn into the instrument and damage the SAW sensor. Also, oil can contaminate the tube, the vapor inlet, the sample stand, and/or other components of the system resulting in erroneous readings. 
     Finally, this test method is very sensitive to oil temperature under test. Due to the high oil volume it takes a long time to cool down the oil sample if oil was freshly collected from a warm or hot engine. Error occurs when sample is not tested at the same temperature as the calibration samples are tested. 
     Moreover, the current system is not portable and requires the sample to be delivered to a laboratory for analysis. 
     SUMMARY OF THE INVENTION 
     In some aspects, provided is a portable fuel dilution meter which is easy to use on site, quick and reliable. Sampling is consistent between samples and the chance of contamination of the meter is reduced. New disposable sample bottles require only a small amount of fluid to be sampled (e.g., 1 ml) and an absorbent material in each sample bottle provides a consistent surface area for vapor build up in the sample bottle headspace as well a heat sink to cool oil samples quickly to room temperature. In some designs, greater range and stability are provided and accuracies of 0.2% wt. with a range of 15% are provided. Up to three stored calibrations can be included to properly sample and detect diesel in oil, gasoline in oil, JP8 fuel in hydraulic oil, and the like. One preferred device is battery operated and uses rechargeable batteries for transportability. A preferred portable fuel dilution meter samples at a rate of approximately 20 seconds per sample. A USB connection may be included for data transfer. 
     Featured is a portable fuel dilution meter comprising a plurality of sample bottles each with a lid securable thereto and an absorbent material in the bottle. A housing includes a receptacle for a bottle. A hinged head unit over the sample bottle receptacle includes at least a first needle piercing the lid of a sample bottle loaded into the housing receptacle and extending into the headspace of the sample bottle when the head unit is closed. A vapor sensor is fluidly coupled to the first needle for analyzing vapors in the headspace of the sample bottle delivered to the vapor sensor. There may be a heater in the receptacle. Further, the sample bottle can be pressurized by the meter pump(s). 
     The hinged head unit may further include a second needle piercing the lid of the sample bottle when the head is closed for allowing ambient air into the headspace of the sample bottle. The absorbent material preferably includes a felt disk disposed at the bottom of each sample bottle. Each felt disk for each bottle is configured the same and each bottle is configured the same. 
     The vapor sensor is preferably a surface acoustic wave sensor. The meter may further include a mechanism for releasably locking the hinged head unit in a closed position. In one design, a clip is provided and a magnet and an adjustable set screw cooperate to retain the head unit in a closed position which can be adjusted relative to the sample bottle lid. 
     Also featured is a detection method comprising disposing one to a few milliliters of fluid into a sample bottle, absorbing the fluid in an absorbent material within the sample bottle, securing a lid onto the sample bottle, placing the sample bottle in a sample bottle receptacle, piercing the sample bottle lid with a first needle, directing vapor in the sample bottle through the needle to a vapor sensor, and analyzing the vapor. 
     Piercing the lid with the first needle may include closing a hinged head unit including the first needle down over the sample bottle receptacle. The hinged head unit may further include a second needle piercing the lid of the sample bottle when the head is closed for allowing ambient air into the headspace of the sample bottle. 
     The absorbent material may include a felt disk disposed at the bottom of each sample bottle. Preferably, each felt disk for each bottle is configured the same and each bottle is configured the same. Example disks have diameters on the order of 12 mm, a thickness of 1 mm, and a microstructure and pore volume consistent with pressed wool. Analyzing the vapor may include directing the vapor to a surface acoustic wave sensor. 
     Also featured is a method of detecting fuel dilution. One preferred method includes disposing one to a few milliliters of oil into a sample bottle, absorbing the oil in an absorbent material disposed within the sample bottle, securing a lid onto the sample bottle, placing the sample bottle in a fuel dilution meter sample bottle receptacle, piercing the sample bottle lid with a first needle, and directing vapor in the sample bottle through the needle to a SAW sensor. 
     A plurality of sample holders for a fuel dilution meter are each preferably configured the same and include a bottle with an open end and a pierceable lid releasably coupled to the bottle open top end. A vapor headspace in the bottle is below the pierceable lid. An absorbent material in the bottle below the vapor headspace absorbs a fluid placed in the bottle and releases vapors into the bottle headspace. The absorbent material may include a felt disk disposed at the bottom of each sample bottle. Preferably, each felt disk for each bottle is configured the same and each bottle is configured the same. 
     The subject invention, however, in other embodiments, need not achieve all these objectives and the claims hereof should not be limited to structures or methods capable of achieving these objectives. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Other objects, features, and advantages will occur to those skilled in the art from the following description of a preferred embodiment and the accompanying drawings, in which: 
         FIG. 1  is a schematic front view of a prior art fuel dilution meter; 
         FIG. 2  is a block diagram showing the primary components associated with the fuel dilution meter of  FIG. 1 ; 
         FIGS. 3-4  are schematic front views showing a portable fuel dilution meter in accordance with an example of the subject invention; 
         FIG. 5  is a schematic view showing the sample bottle lid piercing needles of the portable fuel dilution meter hinged head unit; 
         FIG. 6A  is a schematic view showing a sample bottle placed in the portable fuel dilution meter; 
         FIG. 6B  is a schematic cross sectional view showing a sample bottle disposed in the portable fuel dilution meter and the vapor delivery needle piercing the sample bottle lid; and 
         FIG. 7  is a schematic cross section view showing an example of a disposable sample bottle in accordance with examples of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Aside from the preferred embodiment or embodiments disclosed below, this invention is capable of other embodiments and of being practiced or being carried out in various ways. Thus, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. If only one embodiment is described herein, the claims hereof are not to be limited to that embodiment. Moreover, the claims hereof are not to be read restrictively unless there is clear and convincing evidence manifesting a certain exclusion, restriction, or disclaimer. 
       FIG. 1  shows a prior art laboratory fuel dilution measurement apparatus  10  where large bottle  14  is filled ¾ full with crank case oil and placed in stand  16 . Electronic module  18  includes SAW sensor module  20 ,  FIG. 2  providing an output signal to data acquisition and control microprocessor  22  for detecting the type of vapors in the headspace  24  above the oil  26  level in bottle  14 . In this way, contaminants such as fuel and the like in the oil can be detected. 
     Handle  30 ,  FIG. 1  brings gasket  32  into engagement onto the open top end of bottle  14  and line  34 ,  FIG. 2  delivers vapor to SAW sensor  20  via pump  36 . Purge pump  38  and valve  40  may also be included. 
     As noted in the Background section above, oil, gas, or the like can contaminate gasket  32 ,  FIG. 1 , line  34 ,  FIG. 2 , and/or other components of the system resulting in unreliable readings. Also, if the bottle  14  is filled too full, liquid can be delivered to SAW sensor module  20  damaging it. 
     It was found, for example, that if a first sample of oil with 5% fuel was tested and touched the meter gasket  32  and then a second sample of oil with 1% fuel was tested, the sensor inaccurately reported that the second sample of oil had 2.5% fuel do to the presence of some of the first oil sample still on or in the meter. 
       FIG. 3  shows an example of a new portable fuel dilution meter  50  with housing  52  preferably enclosing an electronic subsystem the same as or similar to that depicted in  FIG. 2 . Preferably, this portable fuel dilution meter is light weight, small in size, and powered by a lithium ion rechargeable battery via a universal charger. Touch screen  51  displays the results of an analysis and can be used as an input device. A range of 0.2% to 15% is featured as is an accuracy of 0.2%. 
     Head unit  54  is hinged to the housing via pin  56  over sample bottle receptacle  53 ,  FIG. 4  in the housing. Clip  55  retains head unit in the closed position. Adjustable set screw  57  on head unit  54  cooperates with magnet  59  on base unit  52  to retain the head unit in the closed position and for spacing adjustment so the needles  60  and  64  properly pierce the sample bottle plastic lid without head unit  54  putting too much pressure on the sample bottle lid. 
       FIG. 5  also shows head unit first needle  60  with a solid pointed tip  62  and side vapor orifice  63 . Needle  60  is used to pierce the lid of a sample bottle and to draw vapor present in the headspace of the sample bottle via orifice  63  and through a conduit  34  connected to needle  60  to a vapor sensor such as depicted in  FIG. 2 . Head needle  64  with a distal bottom opening  66  pierces the sample bottle lid and supplies ambient air into the sample bottle. Needles  60  and  64  may be retained in block  65 . 
       FIGS. 6A and 6B  show sample bottle  72  and pierceable lid  70  loaded into the device receptacle. Conduit  34  (e.g., a tube) is also shown for delivering vapor to a vapor sensor system such as a SAW sensor. The pump used (see  FIG. 2 ) can be operated to pressurize sample bottle  72  via needle  60  to assist in vapor development. Further, receptacle  53  may include a heater coil  65  to control the temperature of the sample bottle in order to ensure a consistent vapor release. Because the sample is low volume, it quickly reaches room temperature. Heater coil  65  can maintain the bottle at consistent temperatures dispute different ambient temperatures. 
     In one preferred design, sample bottle  72 ,  FIG. 7 , and pierceable lid  70  are made of plastic and lid  70  snap fits onto the upper open end of the sample bottle. One bottle was approximately 2 inches tall and approximately 1 inch in diameter.  FIG. 7  also shows absorbent material  74 , e.g., a disk of felt material disposed at the bottom of the sample bottle. Each sample bottle and each disk of absorbent material are preferably configured the same to absorb the sample oil and release the same amount of vapor into the large headspace  76  in the sample bottle between the absorbent disk and the lid of the bottle. That is, each sample bottle is the same size and each absorbent disk is the same diameter, thickness, and has the same microstructure and pore volume. Example disks have diameters on the order of 12 mm, a thickness of 1 mm, and a microstructure and pore volume consistent with pressed wool. Lambs wool may be used as the absorbent disk. 
     In use, a small amount of crank case oil (e.g., one half a milliliter to a few milliliters) is pipetted into the bottle  72  and is absorbed by absorbent disk  74 . Lid  70  is then secured to the sample bottle top. The sample bottle is then loaded into the meter receptacle  53 ,  FIG. 4  and head  54 ,  FIG. 3-6  is pushed down whereupon needles  60  and  64  pierce the sample bottle lid. Vapor is then delivered from the sample bottle headspace to the vapor sensor for analysis. The bottle and the pierced lid are then removed from the machine and discarded. 
     In this way, the chance of contamination of the meter with oil or other contaminants is reduced and oil analysis is simplified. If the sample bottle is tipped or even dropped, no oil can leak out because it is absorbed in the absorbent disk. 
     Note that in the prior art ( FIGS. 1-2 ) bottle  14  is rather large and a large quantity of oil is dispensed into the bottle. There is no bottle lid. Spillage of the oil is a problem as is possible contamination of the meter. It was found that the sample stand was easily contaminated. Further, in the prior art, it took a long time to establish equilibrium in the headspace of the sample bottle. Only a single calibration was possible and the meter was not usable in the field. 
     Although specific features of the invention are shown in some drawings and not in others, however, this is for convenience only as each feature may be combined with any or all of the other features in accordance with the invention. The words “including”, “comprising”, “having”, and “with” as used herein are to be interpreted broadly and comprehensively and are not limited to any physical interconnection. Moreover, any embodiments disclosed in the subject application are not to be taken as the only possible embodiments. 
     In addition, any amendment presented during the prosecution of the patent application for this patent is not a disclaimer of any claim element presented in the application as filed: those skilled in the art cannot reasonably be expected to draft a claim that would literally encompass all possible equivalents, many equivalents will be unforeseeable at the time of the amendment and are beyond a fair interpretation of what is to be surrendered (if anything), the rationale underlying the amendment may bear no more than a tangential relation to many equivalents, and/or there are many other reasons the applicant can not be expected to describe certain insubstantial substitutes for any claim element amended. 
     Other embodiments will occur to those skilled in the art and are within the following claims.