ALCOHOL BREATH TESTER

Abstract: Apparatus for determining the alcohol content in the breath of a human subject. The apparatus comprises a clear cartridge (30) having a top and a bottom, a first oneway valve (36) disposed in the bottom of the container (30) and oriented to permit only ingress to the container (30). An alcohol - sensitive solution (37) is disposed in the container (30) and such solution (37) is formulated to change color in accordance with alcohol combined with the solution (37). A mouthpiece (24) and a body member (12) are also provided having a passageway (14) connecting the mouthpiece (24) to the oneway valve (36) whereby, when the subject exhales through the mouthpiece (24), the breath enters the solution (37) through the oneway valve (36) and flows through the solution (37). The color of the solution (37) then changes in accordance with the quantity of alcohol in the subject's breath.

Description: -i- ALCOHOL BREATH TESTER BACKGROUND OF THE INVENTION Field of the Invention: This invention relates to screening devices for determining the approximate concentration of ethanol in the blood of a user by analyzing samples of expired air. Discussion of Related Art; In recent years, law enforcement officers, as well as the general public, have become increasingly aware of the problems associated with drinking and driving. In many states, increasingly harsh laws are being passed aimed at persons who operate motor vehicles while under the influence of alcohol. While such laws are necessary in order to protect innocent people on the highway, it is difficult for an ordinary person to know when his or her blood alcohol content has risen above legal limits. In fact, many law abiding citizens may inadvertently drive while under the influence of alcohol without actu¬ ally being aware of the fact. There have been for many years various methods of measuring alcohol content in the body, ranging from blood testing to complex spectra- graphic analysis. While it is possible for law enforce¬ ment officers to possess expensive equipment for accurately determining the blood alcohol content of a person, it is simply not possible for a normal individual to possess similar equipment in order to be certain that his or her blood alcohol content is below the legal limit before embarking on a trip by automobile. Consequently, there is a need for a simple, effective and relatively inexpensive device to determine the aoproximate blood levels of ethanol in the human bodv. IM aan /01222 -2- There are various known techniques for determining the blood alcohol content of a person. For example, σ. S. Patent No. 3,552,930 to Borkenstein discloses a breath sampling and analyzing apparatus having a motor driven, multi-station, program directing valve wheel or disk which has passageways for cooperating with a sampling tube, a sample receiving and measuring cylinder, and a delivery tube, in a suitable sequence. A plurality of cams on the disk and a plurality of strategically placed cam-operated switches associated with the disk and with a shuttle piston coordinating switch in the sample receiver and measuring cylinder are provided for establishing and maintaining a sequence of operating steps. A photometer with a sampling ampoule associated with the delivery tube, and a standard ampoule reference are ^provided and associated with a nullmeter and balancing means which provides a direct readout of percent alcohol. ϋ. S. Patent No. 3,582,274 to Keyes discloses a method for quantitative analysis for ethyl alcohol of a sample of breath. The method comprises contacting the sample with a solution of chromate ions and measur¬ ing the decrease of chromate ion concentration. The sample is contacted with a solution comprising a chromate compound in aqueous nitric acid. U. S. Patent No. 3,223,488 to uckey discloses an alcohol indicator for visual determination of the alcohol content in human breath. The device comprises a container such as a balloon for receiving the breath of the subject. The balloon is calibrated to exert a pressure within a predetermined range of pressures when inflated to a predetermined point. A transparent indicator tube is arranged to communicate with the interior of the balloon for receiving breath therefrom. A granular alcohol-sensitive indicator is disposed OMPI within the transparent tube and is comprised of a silica gel impregnated with a liquid alcohol-sensitive reagent. The granular alcohol-sensitive indicator is adapted to chemically react with alcohol to produce a progressive color change, due to the composition of the reagent. SϋZIMARY OF THE INVENTION One object of the present invention is to provide a device which can simply, effectively and relatively inexpensively determine the approximate content of ethanol in the body of a subject. Another object of the present invention is to provide a device which is portable and can easily be carried by a subject whereby the subject's blood alcohol content can be determined anywhere at anytime. A further object of the present invention is to provide a device which can be used by a succession of several persons to provide stable indications of their blood alcohol content at the time of use. Another object of the present invention is to provide a device which can be used in the form of a kit which contains several cartridges of solution. The cartridges are adapted to fit within a main testing apparatus and removed after use. In accordance with the above and other objects, the present invention comprises a clear cartridge or container having a top and bottom. A first oneway valve is disposed in the bottom of the container and oriented to allow gas to enter the container, but not to allow fluid to exit the container. An alcohol- sensitive medium is disposed in the container. The medium is an alcohol-sensitive solution or an inert , -,„„ 4/01222 -_ 4_- material impregnated with alcohol-sensitive solution. The solution i s formulated to change color in varying degrees in accordance with the amount of alcohol com¬ bined with the solution. The apparatus also includes a mouthpiece attached to a connecting-member. The con¬ necting member has a passageway which leads to the first oneway valve. When a subject exhales through the mouth¬ piece, breath enters the alcohol-sensitive medium in the container through the oneway valve and flows up through the alcohol-sensitive medium. The color of the medium changes in accordance with the quantity of alcohol in the subject's breath to provide a stable indication of the subject's blood alcohol content. In accordance with other aspects of the present invention, a second oneway valve is disposed in the passage leading to the first oneway valve and is oriented in the same direction as the first oneway valve. The second oneway valve operates as a secondary barrier to prevent solution from reaching the subject. Either the first oneway valve or the second oneway valve may include a safety means to prevent damage or -harmful pressure in the cartridge or con¬ tainer from excessive pressure. The safety means may also comprise an independent valve in the device. f the subje blows too hard into the device, the safety means blocks the subject's breath from entering the area containing the alcohol-sensitive medium. A preferred safety means comprises a one-piece plastic valve which acts as a stopper when excessive pressure is exerted thereon. In accordance with another aspect of the present invention, the solution comprises a mixture of potassium dichromate and sulfuriσ acid. Other alcohol-sensitive solutions may also be employed such as magnesium MPI - 3 - perchlorate, or a mixture of potassium permanganate and sulf ric acid. The apparatus also includes a color chart contain¬ ing different colored segments for comparison with the color of the alcohol-sensitive medium. The color seg¬ ments are indicative of different levels of alcohol content. These segments can be in the form of vials containing actual colored solution or colored medium or merely samples of respective color chips. The present invention can be provided as a kit which contains the main body having a mouthpiece, a cartridge-receiving opening and a passage connecting the mouthpiece to the opening. A plurality of trans¬ parent cartridges shaped to fit within the opening are provided. Each of the cartridges has a bottom with a ofteway valve disposed therein at a location- for communication with the passage when that cartridge is disposed in the cartridge-receiving opening. The cartridgesmay contain the alcohol-sensitive medium in the form of a solution or by way of an inert material impregnated with solution. Silica gel provides an exceptionally useful inert medium in that it readily absorbs the alcohol-sensitive solution and uniformly retains the solution in amounts suitable for the desired sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the apparatus of the present invention; FIG. 2 is a longitudinal sectional view of the apparatus of the present invention; OMPI ^sfry FIG. 3 is a fragmentary view showing the ton of " one cartridge of the present invention: FIG. 4 is a fragmentary view showing the connection between the bottom of one cartridge and the main body of the present invention; FIG. 5 is a fragmentary view showing the variable inlet aperture of the present invention; and FIG. 6 is a view of the safety valve of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIGS. 1 and 2, an alcohol breath tester 10 according to the present invention is shown. Tester 10 comprises a main body 12 which is formed from a transparent plastic material. Body 12 can be conveniently formed in an injection molding process by molding two halves of the body which are then welded together. Body 12 is generally rectangular in shape and contains a longitudinal passage 14 which communicates with a vertical passage 16. Passage 14 extends out of one end of body 12 and receives a mouthpiece assembly 18. Mouthpiece assembly 18 can be a hollow rubber element having a plurality of ribs 20 which engage with the internal surface of passage 14 to removably hold the mouthpiece assembly within the passage. On the inner end of mouthpiece assembly 18 is a flapper valve 22 which is oriented to allow gas to pass through the mouthpiece assembly into passage 14, but not in the opposite direction. The outer end of mouthpiece assembly 18 contains a mouth¬ piece 24 through which a user of the device exhales. Mouthpiece assembly 13 can be formed as a unitary unit which is inserted into body 12 after the body is manu¬ factured. The mouthpiece assembly 18 is removable so that different mouthpieces can be used for different 5 individuals to improve the sanitary nature of the device. Alternatively, a thin, disposable plastic mouthpiece (not shown) could be used over mouthpiece 24 to reduce the cost of changing mouthpieces. When a subject breathes through mouthpiece assembly 10 18, his or her breath enters passage 14 and passes through a stem 26 positioned between passage 14 and passage 16, as shown in FIG. 4. Stem 26 is hollow to provide com¬ munication between passages 14 and 16. Also, stem 26 includes an outward bulged area 28 which snap-fits within 15 the bottom of a cartridge 30. Cartridge 30 is shown in FIGS. 1 through 4 and comprises a transparent shell 31 which is preferably formed from glass, plastic or other transparent material. Shell 31 has an opening 32 formed in the bottom thereof. An annular seal 34 is 20 attached to opening 32. Seal 34 can be forσeddown over the top of stem 26 and bulge 28 to snap-fit around the bottom portion of the stem. In this manner, cartridge 30 can be slid into passage 16 and snap-fits onto stem 26 which holds the cartridge within the passage. It 25. will, of course, be understood that the diameter of passage 16 is made sufficiently large to accept cartridge 30 without binding or sticking. A flapper valve 36 is disposed inside cartridge 30 above opening 32 and oriented to allow gas to enter upwardly into 0 cartridge 30, but not to allow liquid to leave the cartridge. The interior of cartridge 30 is filled with a solution 37 which is formulated to change color when combined with alcohol. The color of solution 37 5 changes progressively in accordance with the amount of alcohol combined with the solution. Solution 37 -3 - can comprise potassium dichro ate and sulfuric acid. This solution is yellow in color, and the color change produced is in proportion to the amount of alcohol in the breath of the user passed through the solution. 5 In other words, the intensity of the colorchanges •as the amount of alcohol increases. Disposed directly above flapper valve 36 is a quantity of silica gel 54 through which gas from flapper valve 36 must pass before entering solution 37. Silica 10 37 will tend to draw moisture from the subject's breath and keep the mixture passing into solution 37 free of water. A wool plug 56 can optionallybe placed over the silica 54 to hold the silica in place on top of valve 36 and to aid in keeping solution 37 entrapped 15 in shell 31, and separated from silica 54. FIG. 3 shows the top of a cartridge 30. An in¬ sert 38 is disposed in the open top 39 of the cartridge shell 31. Insert 38 can be formed of rubber and con¬ tains a flapper valve 40 on its bottom. Flapper valve 20 40 is oriented upwardly so that gas can exit cartridge 30. Flapper valve 40 forms a portion of a shell 41 which slides into glass shell 31. Immediately above flapper valve 40 within shell 41, a quantity of silica gel 48 is disposed. Silica 48 acts as a drying agent 25 to absorb any spray created by gas bubbling up through solution 37 and flapper valve 40. The silica 48 absorbs the solution and allows the gas to exit through the top of rubber shell 41. A perforated insert 42 is disposed across the top of the silica insert 48 in order to hold 30 the silica in place and yet allow gas to exit. A wool plug 53 may be attached to the bottom of the flapper valve 40 to assist in holding solution 37 within shell 31. Referring to FIGS. 1, 2 and 5, it will be seen that 35 testing device 10 also includes an orifice plate 60 SJR -9- is generally rectangular in shape and fits within rectangular opening 64 which is formed in body 12. The dimensions of plate 60 are such that it completely blocks off passage 14 except for hole or opening 62. Also the dimensions of plate 60 are such as to allow the plate to slide within opening 64. This movement is produced laterally across the body 12 in opening 64 by grasping handle 66 which is integral with plate 6-0 and protrudes from hole 64. As plate 60 is moved to the right, as viewed in FIG. 5, it is clear that the exposed portion of hole 62 becomes pro¬ gressively smaller, thus making it more difficult for the subject to pass breath through passage 14. Accordingly, the air flow through passage 14 can be controlled by moving plate 60 into or out of hole 64. FIG. 1 shows three alternative orifice plates 60a, 60b and 60c. Each orifice plate 60a, 60b and 60c has a different sized central opening. Rather than controlling the flow through passage 14 by moving plate 60 pro¬ gressively into or out of hole 64, plate 60 can be removed entirely from hole 60 and replaced by whichever one of plates 60a, 60b or 60c that has the proper size central opening. The plates 60a, 60b and 60c are marked with indicia shown at 61a, 61b and 61c to indicate the size of the opening in the plate. The alcohol tester can be provided in kit form containing one body 12, a plurality of cartridges 30, and a plurality of orifice plates 60a, 6Qb , 60c or one adjustable orifice plate 60. Each individual cartridge 30 can be inserted into body 12 and removed from the body after use. In order to insure that no solution is lost from cartridge 30, stick-on covers 44 and 46 can be attached to the top and bottom, respectively, of each cartridge 30 as shown in FIG. 1. Prior to use, cover 44 is removed from the cartridge 30. Cover 46 can either be removed or can be left on to be /01222 pierced by stem 26 when the cartridge is snapped into body 12. Body 12 also contains fixed cartridges 50, 51, 52 and 53 which are permanently mounted in the body with two cartridges being placed on each side of remov¬ able cartridge 30. Cartridges 50 through 53 contain precolored solutions 54 through 57. These solutions are indicative of different alcohol levels in the subject's breath. Appropriate markings can be affixed to each cartridge indicating the approximate alcohol content of the subject's breath. Accordingly, after use, the color of solution 37 in removable cartridge 30 is compared to the color of solutions 54 through 57 to determine the actual alcohol content of the subject's breath. Fixed cartridges 54 through 57 are mounted on opposite sides of cartridge 30 to place them closer to cartridge 30 and thereby improve the ease of this com¬ parison. In operation, a mouthpiece assembly 18 is inserted in passage 14. The subject blows through the mouth¬ piece and adjusts orifice plate 60 until it takes approximately 15 secondsto completely exhale through the mouthpiece. A cartridge 30 is then inserted into passage 16 and snapped into place over stem 26. Peel-off top 44 is removed from the cartridge and the device is ready for use. In order to increase accuracy of the device, the subject is advised to swallow several mouthfulls of water before using. The subject then blows into mouthpiece 24 and the subject's breath passes through flapper valve 22 and through hollow stem 26. Since stem 26 penetrated annular seal 34 when the cartridge 30 was inserted, the user's breath passes through stem 26 into the cartridge. Breath then passes flapper valve 36 and bubbles into and through the solution 37 of potassium dichromate and OMP sulfuric acid. The breathgases pass upwardly through the- solution and out through flapper valve 40, silica 48 and perforated top 42. Any spray of the solution €hrough valve 40 is captured by the silica 48. The subject blows several full breaths through the mouth¬ piece to insure that adequate contact is made with solution 37. The alcohol in the breath combines with the solution and the color of the solution begins to change in intensity in proportion to the amount of alcohol in the breath. After waiting approximately ninety seconds, the color change of solution 37 becomes stable and can be compared to the colors of solutions 54 through 57 and matched up. The user then reads the label on a matching solution to determine his or her blood alcohol content. After use, cartridge 30 can be removed from passage 16 and disposed or saved for future reference. Another cartridge is then inserted in passage 16 and the device is ready for another testing by the same person or by another subject. When using the tester 10, it is essential that the device be in a vertical position with cartridge 30 on top of the body 12 for proper operation in order that the subject's breath can bubble up through the solu- tion 37. When in use, the subject is protected from contact with solution 37 by the two flapper valves 22 and 36. If additional protection is required, additional flapper valves can be used. In an advantageous embodiment of the cartridge configuration, a vial approximately 75-100 m long and 6 mm wide is filled with an inert silica gel. The preferred packing length of silica gel is 25 mm approximately in the center portion of the vial. -12- Additional inert packing material such as glass wool may advantageously be employed at each end of the vial for securing the contents of the vial. The silica gel may be oreimpregnated or may be impregnated with the alcohol-sensitive solution after packing. In a preferred embodiment, 6-12 drops of the alcohol-sensitivesolution are added to the vial containing a 25 mm area of silica gel. The solution is absorbed by the silica gel uniformly in a short period of time, the top closure member as described above is then added. This particular configuration of the vial has an advantage over the typeof vial containing solution in that smaller amounts of the alcohol-sensitive solution may be employed. In addition, the color change upon contact with alcohol provides a gradual color spectrum in the silica gel. The alcohol reacts with the alcohol-sensitive solution according to the following equation: 2K-2,CrO_7 + 8H2-SO4. + 3C-2,H5_OH—*2Cr2_ (SO4.)3, + K2-SO4. + 3CH 3 COOH + 11H 2 0 The initial potassium dichromate, K-Cr-O-, is yellow in color and the final reacted product, chromic sulfate, Cr 2 (SO.),, is green. Thus, in the solution containing vial the intensity of color from yellow to green will provide the comparison. On the other hand, in the vial containing impregnated silica gel, the color change will usually be displayed as a gradual change over the lengthof the silica gel. For example, in a 25 mm long area of packed silica gel, the alcohol content of the subject's breath will be proportional -13- to the length of area changed from the original yellow to -green. The area of silica gel first coming into contact with the subject's breath will change color first due to the reaction of the alcohol. The area at the end of the 25 mm packing may not come in contact with any alcohol if all the alcohol is reacted, thus this area will remain yellow. In a specific example the width of the zone of color change is demonstrated as being proportional to the breath alcohol. It is determined that a lower range of breath alcohol detected is about 0-03% by volume alcohol in the subject's blood while the upper range detected is about 0.17%. A color change in the 25 mm packingshowing green color about 8-12 mm or half way up the column indicates a level of from 0.05 to 0.15% alcohol. Green color more than half way up the column indicates the subject's alcohol level could be above the 0.15% level. The results in this example are not quantitative and must, therefore, be interpreted. The advantage of this embodiment rests in the fact the subject will see a definite color change brought about by the alcohol in his breath. The larger the zone of color change (green) the more alerted the subject will be. The above-described operation provides results which are adequate for a preliminary screening test. However, to improve on these results, it is necessary to pass a predetermined volume of breath through cartridge 30 during each test. For this purpose, a one liter, inflatable bag or container 68 can be attached to shell 31 below open top 39 which flares outward at 70, as shown in FIG. 3, for holding the bag. Bag 68 attaches to shell 31 by elastic member 72 which is attached to the open end of bag 63 and snap-fits over flared end 39. OMPI 4/01222 -14- The use of bag 68 improves the accuracy of each test. However, in order to even further increase testing accuracy, the amount of "ALVEOLAR." air passed through tester 10 should be increased. This is accom- pushed by forming bag 63 with a thin area shown at 7'4. When bag 68 becomes full and the pressure in the bag reaches a predetermined level, weakened, thin area 74 ruptures and the bag "pops" to increase the flow of alveolar air through cartridge 30. Of course, rather than use a disposable bag, a bag formed of strong material could be provided with a pressure relief valve which is designed to open abruptly at a pre¬ determined pressure. Accordingly, it will be understood that tester 10 can be used in two ways. For someone who is in a hurry, the"tester can be used without the bag 68 to provide a basic, preliminary screening test for alcohol. With bag 68 on, the results become more accurate and more quantitative since a known quantity of air flows through cartridge 30. The foregoing description is provided for the purpose of illustrating the present invention, but is not meant to be limiting on the scope of protection therefor. Numerous modi ications, additions, and other changes can be made to the present invention by one of ordinary skill in the art without departing from the scope of protection set forth in the accompanying claims.

Claims: WHAT IS CLAIMED IS: 1. An apparatus for determining the alcohol content in the breath of a human subject, said apparatus comprising: a container having a top, a bottom, and a clear color comparison area; a first oneway valve disposed in the bottom of said container and oriented to permit only ingress to the container; an alcohol-sensitive medium disposed in said container, said medium being formulated to change color in accordance with alcohol combined with said medium; a mouthpiece; and a connecting member comprising a main body having a passageway connecting said mouthpiece to said oneway valve, a container-receiving opening, said container disposed in said container-receiving opening, and means for comparing the color of said medium, said means including different colored segments for comparison with the color of said medium, said colored segments being indicative of different levels of alcohol contained in said user's breath; whereby when said subject exhales through said mouthpiece, the breath enters said medium through said oneway valve and flows through said medium, and the color of said medium changes in accordance with the quantity of alcohol in the subject's breath. 2. The apparatus as set forth in Claim 1, wherein a second oneway valve is disposed in said passageway and oriented in the same direction as said first oneway valve. -16- 3. The apparatus as set forth in Claim 1, wherein said medium is a solution. 4. The apparatus as set forth in Claim 1, wherein said medium is an inert material impregnated with analcohol-sensitive solution. 5. The apparatus as set forth in Claim 3, wherein said solution is a mixture of potassium dichro- mate and sulfuric acid. 6. The apparatus as set forth in Claim 4, wherein said solution is a mixture of potassium dichromate and sulfuric acid and said inert material is silica gel. 7. The apparatus as set forth in Claim 1 and further including means for removably holding said container in said container-receiving opening. 8. The apparatus as set forth in Claim 1, wherein each of said segments comprises a vial of pre- colored liquid. -9. The apparatus as set forth in Claim 1, wherein each of the segments comprises a vial of precolored inert material. - 10. The apparatus as set forth in Claim 1, wherein each of the segments comprisesa color chip. O PI 11. The apparatus as set forth in Claim 1, wherein said container has an open top, and further including an insert in said open top, said insert comprising, a oneway valve oriented to allow gas to pass out of said container. 12. The apparatus as set forth in Claim 11 and further wherein said insert comprises porous, absorbent material disposed over said oneway valve. 13. The apparatus as set forth in Claim 7, wherein said holding means comprises a hollow stem disposed between said passageway connecting member and said container-receiving opening, and a seal member attached to the bottom of said container and configured to snap-fit over said hollow stem. . 14. The apparatus as set forth in Claim 1 and further including means for controlling the flow rate through said passageway. 15. The apparatus as set forth in Claim 14, wherein said controlling means comprises an orifice plate having an opening formed therein and means for mounting said orifice plate across said passageway such that said orifice plate opening is disposed in said passageway. 16. The apparatus as set forth in Claim 14, wherein said mounting means is constructed such that the size of said opening disposed in said passageway can be varied to vary the flow rate through said passageway. -13 - 17. The apparatus as set forth in Claim 15 and further including a plurality of orifice plates, each having a different size opening. 18. The apparatus as set forth in Claim 1 a'nd further including a receiving container having a predetermined volume and means for attaching said receiving container to said first-mentioned container whereby said receiving container is filled with gas passing through said first-mentioned container. 19. The apparatus as set forth in Claim 18 and further wherein said receiving container includes means for abruptly releasing gas therefrom when the pressure within said receiving container reaches a predetermined limit. 20. The apparatus as set forth in Claim 1 and further including means for preventing excessive pressure in said container said means including a blocking member which covers the opening of said oneway valve under a predetermined pressure.. 21. A kit for determining the alcohol content in the breath of a humansubject, comprising: a main body having a mouthpiece, a cartridge- receiving opening, and a passage connecting said mouthpiece to said opening; and a plurality of cartridges shaped to fit within said opening, each of said cartridges having a clear color comparison area, and a bottom with a oneway valve disposed therein, and containing an alcohol- sensitive medium formulated to chanσe color when O P combined with alcohol, said valve being located on said cartridge to communicate with said passage when said cartridge is received in said opening. ■• 22. The kit as set forth in Claim 21, herein each of said cartridges has an open top and an open bottom, and includes removable covers over said open top and open bottom. 23. The kit as set forth in Claim 21 and further including means for restricting the flow through said passage. 24. The kit as set forth in Claim 23, wherein said means includes an orifice plate having an opening, and means for mounting said orifice plate such that said opening is disposed in said passageway. 25. The kit as set forth in Claim 24 including a plurality of orifice plates, each having a different size opening. 26. The kit as set forth in Claim 21, wherein said alcohol-sensitive medium is a solution. 27. The kit as set forth in Claim 21, wherein said alcohol-sensitivematerial is an inert material impregnated with an alcohol-sensitive solu¬ tion. 28. The kit as set forth in Claim 26, wherein said alcohol-sensitive solution is a mixture of potassium dichromate and sulfuric acid. OMPI &7 29. The kit as set forth in Claim 27, wherein said alcohol-sensitive solution is a mixture of potassium dichromate and sulfuric acid and said inert material is silica gel.

Inventors: CHILDS RICHARD W, CHILDS ROBERT L, CHILDS, RICHARD, W., CHILDS, ROBERT, L.
Applicants: CHILDS RICHARD W, CHILDS ROBERT L, CHILDS, RICHARD, W., CHILDS, ROBERT, L.
Application year: 1983
Main classification: G01N31
IPC codes: G01N33