System and Method for Qualitative and Quantitative Detection of Substance on Surfaces

Abstract

A surface wipe for the detection of harmful substances on surfaces by producing uniform color change and a color comparator to determine the concentration of harmful substance collected on the wipe by comparing the intensity and hue of the uniform color on the wipe to a calibrated color scale related to specific concentration of the target harmful substance. In operation, the wipe is held from the handle to swipe a suspect surface. The pressure applied by fingers at certain areas on the rigid or flexible top support member of the wipe during the swiping process is transferred to the flexible wipe body. The flexible body of the wipe uniformly distribute the pressure applied by fingers throughout its mass and/or take the shape of irregular and uneven surface allowing the collection and color forming assembly to produce uniform color change that can be quantified by the color comparator.

Claims

1. A surface wipe (100) held by fingers to swipe target surfaces for the detection of substances on surfaces by forming visual and uniform color change, said surface wipe comprising: a handle (130) which functions to hold said surface wipe with fingers during swiping the surface a surface wipe body (110) which functions as cushion to spread the pressure applied by fingers throughout its mass during swiping the surface a top support (120) which functions to localize said handle (130) to said surface wipe body (110) a wiping and color forming assembly (140) which functions to collect and react with a target substance to form color change a bottom support (150) which functions to localize said surface wipe body (110) to said wiping and color forming assembly (140) a glass crushable ampoule (160) filled with reagent

2. The surface wipe (100) of claim 1 wherein said handle (130) is constructed from plastic and attached or glued on top of said top support (120)

3. The surface wipe (100) of claim 1 wherein said top support (120) is constructed from flexible or rigid material and attached or glued from the top of said handle (130) and attached or glued from the bottom to said surface wipe body (110)

4. The surface wipe (100) of claim 1 wherein said surface wipe body (110) is constructed from flexible closed-pores or open-pores material

5. The surface wipe of claim 1 wherein said bottom support (150) is constructed from flexible or rigid material and attached or glued from the top to said surface wipe body (110) and attached or glued from the bottom to said color forming assembly (140)

6. The surface wipe (100) of claim 1 wherein said wiping and color forming assembly (140) consists of a color forming member (141) coated on top of collection member (142)

7. The surface wipe (100) of claim 6 wherein in said collection member (142) is constructed from inert, open-pores and flexible material

8. The surface wipe (100) of claim 1 wherein said glass crushable ampoule (160) is localized inside said surface wipe body (110)

9. A color comparator (200) includes a plurality of predetermined color scale representing a range of masses or concentrations values of a specific substance, said masses or concentrations values are expressed in numbers, and an arbitrary gray scale to enhance the color matching process, said color comparator comprising: a top comparator body (210) having one color scale window (215), at least one numbers window and at least one rivet opening a bottom comparator body (250) having at least one rivet opening at least one-color scale wheel having a predetermined color scale representing a range of masses or concentrations values of a specific substance expressed in numbers, said color wheel has one rivet opening at least one gray scale wheel having arbitrary values expressed in alphabets to enhance the color matching process, said gray scale wheel has one rivet opening at least one comparator inserts which function to separate said top comparator body (210) from said bottom comparator body (250) to allow free movement of said color wheel and said gray scale wheel at least one separator with smooth surface localized between two said color wheels or said one color wheel and said gray scale wheel at least one magnifying lens at least one rivet which functions to localize the different components of said color comparator and allow free rotation of said color scale wheel and said gray scale wheel a disposable protective sleeve which function to protect said color comparator from contamination during use

10. The color comparator (200) of claim 9 wherein said gray scale wheel is localized under and coaxial with said top comparator body (210), and on top and coaxial with said color scale wheel

11. The color comparator (200) of claim 9 wherein said color scale wheel is localized under and coaxial with said gray scale wheel, and on top and coaxial with said bottom comparator body (250)

12. The color comparator (200) of claim 9 wherein said insert is attached from the top to said top comparator body (210) and attached from the bottom to said bottom comparator body (250)

13. The comparator (200) of claim 9 wherein said rivet is coaxial with said top comparator body rivet opening, said bottom comparator rivet opening, said gray scale wheel rivet opening and said color scale wheel rivet opening

14. The comparator (200) of claim 9 wherein said color scale wheel is constructed from transparent or opaque, rigid or flexible plastic

15. The comparator (200) of claim 9 wherein said gray scale wheel is constructed from transparent, rigid or flexible plastic

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is a schematic drawing of one embodiment of the surface wipe (100) and the color comparator (200) of the present invention.

[0015] FIG. 2A is a schematic drawing of the surface wipe (100) of the present invention.

[0016] FIG. 2B is a cross section of one embodiment of the surface wipe (100).

[0017] FIG. 3A is a cross section of another embodiment of the surface wipe (100) where a crushable ampoule is located inside the wipe's body.

[0018] FIG. 3B depicts a cross section view perpendicular to the cross section shown in

[0019] FIG. 3A.

[0020] FIG. 4 is an exploded view of one embodiment of the surface wipe (100) of the present invention.

[0021] FIG. 5 is a schematic drawing of the surface wipe (100) in use for wiping smooth surface.

[0022] FIG. 6 is a schematic drawing of the surface wipe (100) in use for wiping irregular and rough surface.

[0023] FIG. 7 is an exploded view of one embodiment of the color comparator (200) of the present invention where the top wheel is first gray scale wheel (220) and the bottom wheel is first color wheel (240).

[0024] FIG. 8 is an exploded view of another embodiment of the color comparator (200) of the present invention where the top wheel is second color wheel (242) and the bottom wheel is first color wheel (240).

[0025] FIG. 9 is a top view of one embodiment of the color comparator (200) showing more detail of the first numbers window (213) and showing the alphabets (227) on the first gray scale wheel (220) and the numerals (247) on the first color wheel (240).

[0026] FIG. 10 is a schematic drawing of the surface wipe (100) and one embodiment of the color comparator (200) in use to determine the amount of substance collected on the surface wipe.

[0027] FIG. 11 is an exploded view of yet another embodiment of the color comparator (200).

[0028] FIG. 12 is a top view showing the overlap of the first color wheel (240) and the third color wheel (245) of one embodiment of the color comparator (200).

[0029] FIG. 13A is a schematic drawing of one embodiment of the first color wheel (240).

[0030] FIG. 13B is a schematic drawing of one embodiment of the arbitrary first gray scale wheel (220).

LIST OF NUMERALS

[0031] 100 is surface wipe assembly [0032] 110 is wipe body [0033] 111 is wipe body cavity [0034] 120 is top support [0035] 130 is handle [0036] 140 is the wiping and color forming assembly [0037] 141 is color forming member [0038] 142 is wiping member [0039] 150 is bottom support [0040] 151 is bottom support opening [0041] 160 is crushable ampule [0042] 200 is color comparator assembly [0043] 210 is top comparator body [0044] 211 is rivet first top opening [0045] 212 is rivet second top opening [0046] 213 is first numbers window [0047] 214 is second numbers window [0048] 215 is color scale window [0049] 216 is first magnifying lens [0050] 217 is second magnifying lens [0051] 220 is first gray scale wheel [0052] 221 is first gray scale wheel rivet opening [0053] 225 is second gray scale wheel [0054] 226 is second gray scale wheel rivet opening [0055] 227 are alphabets on the first gray scale wheel (220) [0056] 230 is comparator insert [0057] 231 is right comparator insert member [0058] 232 is left comparator insert member [0059] 240 is first color wheel [0060] 241 is first color wheel rivet opening [0061] 242 is second color wheel [0062] 243 is second color wheel rivet opening [0063] 245 is third color wheel [0064] 246 is third color wheel rivet opening [0065] 247 are the numerals on the first color wheel (240) [0066] 250 is bottom color comparator body [0067] 251 is rivet first bottom opening [0068] 252 is rivet second bottom opening [0069] 260 is first separator [0070] 261 is second separator [0071] 270 is first rivet [0072] 271 is second rivet [0073] 280 is protective sleeve [0074] 300 is irregular surface

DETAILED DESCRIPTION OF THE INVENTION

[0075] The present invention is a surface wipe, generally indicated as (100) in figures, for the detection of harmful substances on surfaces by producing uniform color change, and a color comparator to determine the concentration of harmful substance collected on the surface wipe (100) by comparing the intensity and hue of the uniform color on the surface wipe to a calibrated color scale related to specific quantities and/or concentrations of the target harmful substance, the color comparator is generally indicated as (200) in figures, as will be described more fully herein below.

[0076] In operation, the surface wipe (100) is held from the handle (130), preferably, using the thumb and index fingers to swipe a suspect surface contaminated by harmful substance. The pressure applied by thumb and index fingers at certain areas on the rigid or flexible top support member (120) during the swiping process is transferred to the flexible body (110). The flexible body of the surface wipe (110) uniformly distribute the pressure applied by fingers throughout its mass and/or take the shape of irregular and uneven surface allowing the collection and color forming assembly (140) to produce uniform color change that can easily and accurately be quantified by the color comparator (200).

[0077] The handle (130) is constructed from clear or opaque flexible polyester, polypropylene, polyethylene or any plastic satisfies its intended function of holding the surface wipe (100), preferably, using the thumb and index fingers. The handle (130) is attached or glued to the top support (120).

[0078] The top support (120) is constructed from clear or opaque rigid or flexible polyester, polypropylene, polyethylene or any plastic satisfies its intended function of holding the handle (130) to the surface wipe body (110). The top support (120) is attached to the surface wipe body (110) with adhesive or double-sided adhesive tape. The adhesive and the adhesive tape are preferably constructed from silicon, but it can be acrylic or any kind of adhesive that doesn't off-gas any substance that may damage the active ingredient(s) of the collection and color forming assembly (140).

[0079] The surface wipe body (110) is constructed from closed or open pores, flexible foam or rubber and functions as a cushion to spread the pressure applied by fingers during the swiping process through its mass. In one embodiment, where the top support (120) is rigid plastic, the pressure applied by fingers during the swiping process is spread uniformly through the surface wipe body (110). In another embodiment, where the top support (120) is flexible plastic, the pressure applied by fingers at certain areas, during the swiping process, causes the top support (120) and the surface wipe body (110) to bend and take the shape of fingers tips, while the surface wipe body (110) functions as a cushion spreading the pressure applied by the fingers throughout its mass. The flexibility of the surface wipe body (110) also functions to take the shape of irregular and rough surfaces allowing the collection and color forming assembly (140) to uniformly swipe the target irregular and rough surfaces. In yet another embodiment, the surface wipe body (110) has a cavity (111) for placing a crushable ampoule (160). The crushable ampoule (160) may contains liquid, such as water or alcohol. In this embodiment, the ampoule is crushed before swiping the surface to wet the collection and color forming assembly (140) to maximize the collection of target substance from the surface. In another embodiment, the crushable ampoule (160) contains a reagent or reagents needed to react with the color forming member (141) before swiping the target surface to allow color formation in case target substance found on surface. In yet another embodiment, the crushable ampoule (160) contains a reagent or reagents needed to react with the color forming member (141) and the target substance after the swing process when the target substance already collected on the collection member (142).

[0080] The bottom support (150) is constructed from clear or opaque flexible polyester, polypropylene, polyethylene or any plastic satisfies its intended function of attaching the collection and color forming assembly (140) to the surface wipe body (110). In one embodiment, the bottom support (150) have adhesive or double-sided adhesive tape from both sides to attach the surface wipe body (110) to the collection and color forming assembly (140). The adhesive and double-sided adhesive tape are preferably constructed from silicon, but it can be acrylic or any kind of adhesive that does not off-gas any substance that may damage the active ingredient(s) of the collection and color forming assembly (140). In another embodiment, the bottom support (150) has an opening or perforation (151) to allow the reagent(s) from the crushed ampoule (160) to pass to the collection and color forming assembly (140).

[0081] In one embodiment, the collection and color forming assembly (140) is constructed from inert felt, fiber glass or open pores, flexible plastic such as polypropylene and or polyethylene impregnated with reagent or reagents capable of forming color when reacting with target substance. In other embodiment, the impregnated reagents in the collection and color forming assembly (140) are activated by an activating reagent from the crushable ampoule (160) before swiping the target surface. In yet another embodiment, after swiping the target surface, the crushable ampoule (160) is crushed and the released reagent(s) react with the impregnated reagent or reagents in the collection and color forming assembly (140) and the collected target substance to form uniform color change.

[0082] In other embodiment of the collection and color forming assembly (140), the collection member (142) is constructed from inert felt, fiber glass or open pores, flexible plastic such as polypropylene and or polyethylene. The color forming member (141) is coated on top of the collection member (142), the side facing the bottom support member (150). The color forming member (141) is constructed from colorimetric reagent(s), porous support(s) and inert binder(s) forming uniform emulsion coated uniformly on top of the collection member (142), the side facing the bottom support member (150).

[0083] In one embodiment of the current invention in use, the swiped surface wipe (100) is placed upside-down next to the color scale window (215) on the color comparator (200) as shown in FIG. 10. The first color wheel (240) is then turned until a color match on the wipe (100) and specific color on the first color wheel (240) appears through the color scale window (215) is achieved. The number appears on the first number window (213) corresponds to specific amount or concentration of the target substance collected on the wipe (100). The amount of target substance can be expressed in milligrams (mg) or micrograms (g). When a certain area, i.e. 1 ft.sup.2 or 10 cm.sup.2, of the suspect surface is swiped, the number appears on the first number window (213) corresponds to specific concentration of the target substance collected on the wipe (100) expressed in mg/ft.sup.2 or g/cm.sup.2.

[0084] In one embodiment, the color comparator (200) of the present invention is constructed from first color wheel (240) located under, and coaxial with, first gray scale wheel (220). The coaxial first color wheel (240) and the first gray scale wheel (220) are sandwiched between, and coaxial with, top comparator body (210) and bottom comparator body (250). The top comparator body (210) and bottom comparator body (250) are separated by the comparator insert (230) to allow free rotation and turning of the coaxial first color wheel (240) and the first gray scale wheel (220). The coaxial first color wheel (240) and the first gray scale wheel (220) are separated by first separator (260) having smooth surface from both sides. In use the first separator (260) allows finger, preferably thumb, to smoothly turn the top first gray scale wheel (220) while other finger, preferably index finger, to hold the bottom first color wheel (240) in place. The first separator also allow finger, preferably thumb, to hold top first gray wheel (220) in place while other finger, preferably index, to easily turn bottom first color wheel (240). The axis of the coaxial (210), (220), (240) and (250) can be a screw and nut or rivet (270).

[0085] FIG. 1 depicts a general view of one embodiment of the surface wipe (100) and the color comparator (200) of the present invention. FIG. 4 shows an exploded view of one embodiment of the surface wipe (100) depicted in FIG. 1, and FIG. 7 shows an exploded view of the embodiment of the color comparator (200) depicted in FIG. 1 and will be described in detail herein below.

[0086] FIG. 2A is more detailed illustration of one embodiment of the surface wipe (100) showing the handle (130), the top support (120), the wipe body (110), the bottom support (150), a color forming member (141) and a collection member (142).

[0087] FIG. 2B is a cross section of the surface wipe (100) depicted in FIG. 1A, where the color forming member (141) is coated on top of the collection member (142).

[0088] FIG. 3A is another cross section of the surface wipe (100) where the surface wipe body (110) has a cavity (111) to accommodate a crushable ampoule (160) and the bottom support has an opening or perforation (151) to allow the reagent(s) from the crushed ampoule (160) to pass to the collection and color forming assembly (140).

[0089] FIG. 3B depicts a cross section view perpendicular to the cross section shown in FIG. 3A.

[0090] FIG. 4 is an exploded view of one embodiment of the surface wipe (100). In this embodiment, the handle (130) is a round plastic bended in the middle at right angle and glued to the top support (120). The handle (130) has a diameter 0.75 to 2.0 inch, preferably 1.25 inch and thickness of 2 thousandths of an inch (2 mils) to 50 mils, preferably 7 mils. The top support (120) is a flexible or rigid plastic having diameter of 0.75 to 2.0 inch, preferably 1.25 inch and a thickness of 25 to 100 mils, preferably 50 mils. The surface wipe body (110) is flexible plastic or rubber having a diameter similar to the top support (120) and a thickness of 0.3 to 0.7 inch, preferably 0.35 inch. In this embodiment, the surface wipe body (110) have a cavity (111) to accommodate the crushable ampoule (160). The bottom support (150) is a flexible plastic or rubber having a diameter similar to the top support (120) and thickness of 25 to 100 mils, preferably 50 mils. In this embodiment, the bottom support (150) has an opening or perforation (151) to allow the reagent(s) from the crushed ampoule (160) to pass to the collection and color forming assembly (140). The collection and color forming assembly (140) is constructed from inert felt, fiber glass or open pores, flexible plastic impregnated with reagent or reagents capable of forming color when reacting with target substance. The collection and color forming assembly (140) have a diameter similar to the bottom support (150) and thickness of 5 to 20 mils, preferably 10 mils. Example of reagents

[0091] FIG. 5 showing the surface wipe (100) in use swiping a smooth surface. In a preferred embodiment, the handle (130) is held using thumb and index fingers.

[0092] FIG. 6 showing the surface wipe (100) in use swiping irregular and rough surface. In a preferred embodiment, the handle (130) is held using thumb and index fingers. The pressure applied by fingers at certain areas, during the swiping process, causes the top support (120) and the surface wipe body (110) to bend and take the shape of fingers tips, while the surface wipe body (110) functions as a cushion spreading the pressure applied by the fingers throughout its mass. The flexibility of the surface wipe body (110) also functions to take the shape of irregular and rough surfaces allowing the collection and color forming assembly (140) to uniformly swipe the target irregular and rough surfaces.

[0093] FIG. 7 is an exploded view of one embodiment of the color comparator (200) depicted in FIG. 1. The top comparator body (210) is constructed from plastic preferably polypropylene or polyethylene and it can also be constructed from cardboard. The top comparator body (210) has a length between 3.5 and 5.0 inches, preferably 4.0 inches, width between 3.5 and 5.0 inches, preferably 4.0 inches and thickness of 10.0 and 25.0 mils, preferably 15.0 mils. The top comparator body (210) has color scale window (215) aligned on top of the gray scale of the first gray scale wheel (220) and the color scale of the first color wheel (240). The top comparator body (210) has also first numbers window (213) aligned on top of the alphabets or the numbers (227) on the first gray scale wheel (220) and the numbers (247) on the first color wheel (240). A first magnifying lens (216) is attached on top of the first numbers window (213) to magnify the alphabets (227) and numbers (247) appear on the first numbers window (213) from the first gray scale wheel (220) and the first color wheel (240) to enhance the visual appearance of the alphabets and numbers. The top comparator body (210) has a third opening, the rivet first top opening (211), coaxial with the first gray scale wheel rivet opening (221), the first color wheel rivet opening (241) and the rivet first bottom opening (251). The first gray scale wheel (220) is constructed from transparent plastic such as polyester or polystyrene having a diameter between 3 inches and 5 inches, preferably 3.6 inches and thickness between 5 mils and 15 mils, preferably 10 mils. The first gray scale wheel (220) has an arbitrary gray scale to enhance the color matching process and has no effect in determining the quantity or concentration of the collected target substance on the surface wipe (100). The gray scale can be step increments of gray color as shown in FIG. 13B or gradual smooth increments. The gray scale can be gray color or brown color to match the color of soil or dirt. The first gray scale wheel (220) has an opening in the middle, the first gray scale wheel rivet opening (221), coaxial with and under the rivet first opening (211) and on top of the first color wheel rivet opening (241). The comparator's insert (230) function to separate the top comparator body (210) from the bottom comparator body (250) and allow free movement and turning of the first gray scale wheel (211) and the first color wheel (240). The comparator's insert (230) is constructed from plastic such as polypropylene and polyethylene and it can also be constructed from cardboard. The comparator's insert (230) has a length between 3.5 and 5.0 inches, preferably 4.0 inches, width between 3.5 and 5.0 inches, preferably 4.0 inches and thickness of 15.0 and 40.0 mils, preferably 20.0 mils. The comparator's insert (230) is attached to the top comparator body (210) and the bottom comparator body (250) with adhesive, double-sided adhesive tape or riveted or screwed. The first color scale wheel (240) is constructed from transparent or opaque plastic such as polyester or polystyrene having a diameter between 3 inches and 5 inches, preferably 3.6 inches and thickness between 5 mils and 15 mils, preferably 10 mils. The first color scale wheel (240) has a color scale that match the colors produced on the surface wipe (100) upon swiping target surface contaminated with different quantities or concentrations of target substance. The color scale can be step increments of color as shown in FIG. 13A or gradual smooth increments as shown in FIG. 13B. The first color scale wheel (240) has an opening in the middle, the first color scale wheel rivet opening (241), coaxial with and under the rivet first opening (211) and the first gray scale wheel rivet opening (221).

[0094] FIG. 8 is an exploded view of another embodiment of the color comparator (200) depicted in FIG. 1 where two color wheels are depicted coaxial on top of each other to increase the concentrations span of the color comparator. For example, the second color wheel (242) has color scale calibrated to measure concentrations from 1 mg to 100 mg and the first color wheel (240) has scale calibrated to measure concentrations from 100 mg to 1000 mg. Hence, in this embodiment, the color comparator is capable of measuring concentrations from 1 mg to 1000 mg. In operation, user place the swiped wipe (100) upside down on the color comparator, as shown in FIG. 10 and then turns the first color wheel (240) until ND (not detected) appears on the lower half of the first number window (213), then turning the second color window (242) until color match appears on the color scale window (215). If the color on the surface wipe is darker than the darkest color on the second color wheel (242), the second color wheel is turned until (ND) appears on the top half of the first number window (213) and the first color wheel (240) is turned until color match appears

[0095] The color wheel (240) has color scale designated to specific concentrations of the target substance. The color wheel can be transparent or opaque. The gray scale wheel (220) is transparent wheel located on top of the color wheel (240) and has arbitrary gray scale to enhance the color matching process and it has no effect in determining the quantity or concentration of the harmful substance collected on the wipe.

[0096] FIG. 9 is top view of one embodiment of the color comparator (200) depicted in FIG. 1 and FIG. 7.

[0097] FIG. 10 is a schematic drawing of one embodiment of the surface wipe (100) and color comparator (200) in use to determine the amount of substance collected on the surface wipe. In this embodiment, the protective sleeve (280) is inserted into the left side of the color comparator (200) and the swiped surface wipe is placed on top of the protective sleeve (280) with the swiping surface (142) facing up and next to the color scale window (215). The protective sleeve (280) function to protect the color comparator (200) from contamination of toxic substance that might be collected on the surface wipe (100). The protective sleeve is disposable, preferably constructed from transparent plastic such as polyethylene or polypropylene, but it can be constructed from any flexible none porous substance that satisfy its intended use.

[0098] FIG. 11 is an exploded view of another embodiment of the color comparator (200) where one set of color wheels (240) and (245) and one set of gray scale wheels (220) and (225) are included to increase the span measurement of the comparator or to determine the concentrations of two different contaminants. The first color wheel (240) is located under and coaxial with the first gray scale wheel (220). The first color wheel (240) and the first gray scale wheel (220) are separated by the first separator (260) for smooth movement of the wheels. The third color wheel (245) is located under and coaxial with the second gray scale wheel (225). The third color wheel (245) and the second gray scale wheel (225) are separated by the second separator (261) for smooth movement of the wheels. The first rivet (270) is inserted into the rivet first bottom opening (251) passing through the coaxial first color wheel rivet opening (241) and the first gray scale wheel rivet opening (221) and riveted to the comparator body (210) at the rivet first top opening (211). Similarly, the second rivet (271) is inserted into the rivet second bottom opening (252) passing through the coaxial third color wheel rivet opening (246) and the second gray scale wheel rivet opening (226) and riveted to the comparator body (210) at the rivet second top opening (212). In this embodiment the color comparator can be designed to determine the concentration of one contaminant, the first color wheel (240) is calibrated to measure concentrations between 1 mg and 1000 mg, and the third color wheel (245) is calibrated to measure concentrations between 1,000 mg and 10,000 mg. In operation the swiped surface wipe (100) is placed upside down with the wiping member (142) facing up next to the color scale window (215). The third color wheel (245) is rotated until the letter ND appeared in the second numbers window (214) and the second gray scale wheel (225) is rotated until the number zero (0) appears in the second numbers window (214). The first color wheel (240) and the first gray scale wheel (220) are rotated until a color match appear in the color scale window (215). If the color on the wiping member (142) is darker than the darkest color on the first color wheel 240), then the first color wheel (240) is rotated until the letter ND appears in the first numbers window (213) and the first gray scale wheel (220) is rotated until the number zero (0) appears in the first numbers window (213). The third color wheel (245) and the second gray scale wheel (225) are then rotated until a color match appear in the color scale window (215). In yet another alternative embodiment of the color comparator, the two gray scale wheels are replaced with two color wheels. The four-color wheels can be designed to measure one contaminant for wide range of measuring the concentration of one contaminant, or each pair of coaxial color wheels measuring different contaminant, in this case the comparator capable of measuring two different contaminants. Or each of the four-color wheels are designed to measure different contaminant, in this case the comparator is capable of measuring the concentration of four different contaminants.

[0099] FIG. 12 is a top view of two-color wheels (240) and (245). The two-color wheels can be designed to measure one contaminant for expand range of measurement, or the two wheels can be designed to measure two different contaminants.

[0100] FIG. 13A is top view of the first color wheel (240) where the color scale is gradually and smoothly increases. The first and second gray scale wheels (220) and (225) can also be designed with gradual and smooth gray scales.

[0101] FIG. 13B is top view of the first gray scale wheel (220) where the gray scale is gradual step increments. The first, second and third color wheels (240), (242) and (245) can also be designed with gradual step increments scales.

[0102] Several embodiments of the present invention have been described herein. It should be understood by those of ordinary skill in the art, however, that the above described embodiments, are set forth merely by way of example and should not be interpreted as limiting the scope of the invention. Other alternative embodiments, variations and modifications of the foregoing embodiments that embrace various aspects of the present invention will also be understood upon reading of the detailed description in light of the prior art.