WO1985004016A1

WO1985004016A1 - Disposable breath analyzer device and method of fabrication

Info

Publication number: WO1985004016A1
Application number: PCT/US1984/000345
Authority: WO
Inventors: Robert E. Ii Schmitz; Lawrence L. Courter
Original assignee: Diversified Medical Technologies, Inc.
Priority date: 1984-03-08
Filing date: 1984-03-08
Publication date: 1985-09-12
Also published as: EP0173682A1

Abstract

A pocket-size, disposable breath analyzer device (10). The device (10) has a colorimetric chemical material (62) which is adapted to provide a visual color indication of the amount of alcohol contained in a user's breath sample blown through the device. The structural components are formed of a high impact strength polymeric compound which is devoid of any organic mold release agents, ketones, esters or peroxides so as to be inert with respect to the colorimetric chemical material (62) stored within the device (10). The present invention also incorporates the use of valves (70) to prevent back aspiration of air through the housing (12) and a quantity on inert gas trapped within the housing (12) in order to prolong the shelf life of the device (10).

Description

DISPOSABLE BREATH ANALYZER DEVICE AND METHOD OF FABRICATION Background of the Present Invention The present invention relates generally to devices for measuring alcohol content of gasses and, more particularly, to a portable, pocketsize, disposable breath analyzer device for determining the blood alcohol content of a user's breath sample blown through the device. As is well known, there are two prior art methods which are generally utilized to determine the blood alcohol concentration level of an individual; the first being actual blood sample analysis and the second being breath sample analysis. Blood sample analysis, although being typically accurate, necessarily requires an invasion or intrusion into the body of an individual which thereby prohibits its use for self-evaluation by individuals and additionally raises constitutional concerns for use by law enforcement personnel. Further, once a blood sample has been obtained by withdrawal from an individual, actual analysis of the blood sample is generally limited to only professional trained laboratory technicians. In contrast, breath sample analysis correlates the amount of alcohol in the user's breath sample with the amount of alcohol in the same user's blood. Although such breath analysis does not require an actual intrusion into an individual's body, it additionally suffers from the inability to routinely provide an on-the-scene determination of blood alcohol level due to the prior art analysis equipment of such breath samples typically comprising extremely costly laboratory apparatus which must additionally be administered by trained laboratory personnel.

Thus, there exists a substantial need in the art for means for allowing both individual users as well as

OMPI law enforcement personnel to make reliable, low-cost noninvasive determinations of blood alcohol concentrations in a rapid and expeditious manner.

This need was recognized by Robert E. Schmitz, II, the co-inventor of the subject application, who developed a disposal breath analyzer embodied in United States patent application Serial No. 508,108, filed June 27, 1983, the disclosure of which is expressly incorporated herein by reference. This prior art disposable breath analyzer was characterized by a tubular housing having an end portion formed to be placed in the mouth of a user and a central portion carrying a canister filled with a colorimetric chemical material, more particularly potassium dichromate impregnated silica gel. Although such potassium dichromate impregnated silica gel provides a suitable visual color indication of the amount of alcohol contained in the user's breath sample, it readily reacts with oxygen such as that contained in air and water and, therefore, poses a substantial safety hazard to a user if accidentally back aspirated or inhaled into a user's lungs or comes in contact with the user's skin. Further, potassium dichromate impregnated silica gel has been found to additionally react to organic compounds, ketones, esters, and peroxides such as those typically found in modern polymeric compounds .

Due to the reactivity of potassium dichromate impregnated silica gel, use of the same in disposable breath analyzers has heretofore required the use of glass as a housing material for the breath analyzers. Fabrication of glass housings has proven to be, of course, more costly than use of modern molded or extruded polymeric compounds and therefore has necessarily raised the overall cost of such disposable breath analyzer devices. In addition, the sheer, tensile

OMPI and impact strength of glass is limited which has caused concerns as to breakage of the glass housings for such analyzer devices and possible exposure of the users to the highly reactive and dangerous potassium dichromate silica gel compound.

Thus, there still exists a need in the art to provide a more economical material which is inert with respect to potassium dichromate impregnated silica gel yet may be fabricated into suitable structural components by way of economical mass production fabrication techniques and which possess suitable structural strength so as to prevent any accidental breakage and exposure of the potassium dichromate impregnated silica gel to the user. Summary of the Present Invention

The present invention specifically addresses and alleviates the above-referenced needs in the art by providing a pocketsized disposable breath analyzer device formed of a high impact strength polymeric compound which is inert with respect to potassium dichromate impregnated silica gel contained within the device adapted to provide a visual color indication of the amount of alcohol contained in a user's breath sample blown through the device. More particularly, the present invention discloses a novel structure, polymeric housing material and method of fabrication of a disposable breath analyzer device which provides user safety in operation and insures prolonged shelf-life of the device. The device is formed having a tubular polymeric housing having an end portion formed to be placed in the mouth of a user and central portion which carries a quantity of colorimetric chemical material, more particularly potassium dichromate impregnated silica gel. The particular polymeric compound utilized for the housing material is characterized by high impact strength and which is completely devoid of any organic compounds such as internal mold release agents as well as ketones, esters, and peroxides. In addition, during the fabrication of the housing as by way of extrusion or molding techniques, no organic mold or part release agents are applied to the tooling, thereby insuring that the final housing components will remain inert with respect to the potassium dichromate impregnated silica gel colorimetric compound.^"

To insure user safety, the present invention additionally incorporates a pair of valve members positioned on opposite sides of the colorimetric material adapted to prevent any back aspiration of air from the colorimetric compound into the user's lungs. Further, these valve members in their normally closed position, prevent any accidental entrance of air, moisture or the like into the chemical bed prior to use of the device for analysis purposes. The present invention additionally discloses ^' a novel method of fabricating and assembling the breath analyzer device in a manner to insure that the colorimetric material is purged of any moisture or air during insertion into the housing of the device and subsequently maintained in a hermetically sealed environment so as to prolong useful shelf life.

Description of the Drawing These as well as other features of the present invention will become more apparent upon reference to the drawings, wherein:

Figure 1 is a perspective view of the disposable breath analyzer device of the present invention;

Figure 2 is an exploded perspective view of the breath analyzer device of the present invention with its end caps removed;

OMPI

™ Figure 3 is a cross-sectional view of the disposable breath analyzer device of the present invention with its end caps removed;

Figure 4 is a perspective view of one of the screens disposed within ^' the interior of the breath analyzer device of the present invention;

Figure 5 is a perspective view showing the construction and operation of the valving members utilized in the disposable breath analyzer of the present invention;

Figure 6 is a fragmentary perspective view of the housing of the breath analyzer device of the present invention;

Figures 7 through 12 are schemetic views depicting the sequential steps in the method of assembling the disposable breath analyzer device of the present invention; and

Figure 13 is a perspective view of the packaged disposable breath analyzer of the present invention. Detailed Description of the Preferred Embodiment

Referring to Figures, there is shown the disposable breath analyzer device 10 of the present invention composed of a housing designated generally by the numeral 12, a chemical bed sleeve 14, and a pair of end caps 16 and 18. The housing 12 is formed by a cylindrical main body portion 20 and mouthpiece portion

22 which are rigidly interconnected by an interference fit to join at an abutment shoulder 24. Both the main body portion 20 and mouth piece portion 22 include axial apertures 24 and 26, respectively, with the axial aperture 24 terminating at the distal end 28 of the body portion 14 in a plurality of openings 30. A pair of rectangular openings or windows 32 are additionally provided in the main body portion 20 which extend radially through its cylindrical. The main body portion 12 additionally includes a locating shoulder 34 which extends radially inward within the interior of the aperture 24 adjacent the distal end 28. As will be explained in more detail infra, the rectangular windows 32 permit viewing within the interior of the housing 12 while the locating shoulder 34 serves to maintain the axial orientation of the chemical bed sleeve 14 within the main body portion 20.

The chemical bed sleeve 14 preferably is formed in an elongate tubular configuration having a central aperture 40 extending therethrough and a registry shoulder 101 adjacent its distal end. The outside diameter of the chemical sleeve bed 14 is sized to be slightly less than the diameter of the central aperture 24 of the main body portion 20 and includes a pair of radially extending circumferential ribs 42. The diameter of the central aperture 40 of the chemical bed sleeve 14 is sized to be equal approximately to the diameter of the central aperture 26 of a mouth piece portion 22. As such^*, when the chemical bed sleeve 14 is inserted within the interior of the main body portion 20, the circumferential ribs 42 form a tight interference seal between the sleeve 14 and body portion 20 while the apertures 26 and 40 and openings 30 formed in the distal end 28 of the body portion 20 form a central flow passage through the housing 12.

Four screens 50 are positioned within the interior of the chemical bed sleeve 14 at differing axial locations. Each of the screens 50 are formed in a generally cup-like configuration, the outside diameter of which is slightly greater than the diameter of the aperture 40 such that the screens are maintained in a slight interference fit within the aperture 40. A plurality of apertures 52 are provided in each of the screens 50, the size of which are designed to provide an

_ OMPI equivalency to nine to twelve mesh grid. Suitable quantities of indicating desiccant 60 colorimetric compounds 62 and nonindicating silica gel 64 is positioned between adjacent screens 50. As is well known, the indicating desiccant serves to remove water vapor from the breath sample blown through the device 10 while the nonindicating silica gel 64 serves to provide a color comparison basis. The colorimetric chemical compound 62 is characterized by its ability to scrub or absorb alcohol carried by a gas and upon absorption of the same, experience a visual color change. Although a variety of colorimetric compounds may be utilized, in the preferred embodiment, a potassium dichromate impregnated silica gel compound is utilized which by _ appropriate buffering by use of sodium bisulfate may have the particular absorption rate of alcohol be modified. In addition, by use of differing catalyst agents, the particular visual color derived during absorption may be modified.As will be recognized, the screens 50, although forming a barrier to migration of the desiccant 60 potassium dichromate impregnated silica gel 62 and nonindicating silica gel 64, permit unrestricted air flow through the aperture 40 of the chemical bed sleeve 14. Disposed adjacent opposite ends of the chemical bed sleeve 14 are a pair of valving members 7 which serve to permit gas flow through the housing 12 in only one direction, i.e. in the direction from the mouthpiece portion 22 toward the openings 30 in a distal end 28 of the housing 12. The valve members 70 are each formed by a pair of thin planer disks 72 and 74 which are sandwiched together so as to tightly abut one another. The disk 72 is formed having a central aperture 76 extending therethrough, the size of which is less than the diameter of the aperture 40 of the chemical bed 14. The disk 74 includes a C-shaped opening 78 extending therethrough which forms a disk-shaped cover portion 80 within its interior. The diameter of the cover portion 80 is sized to be greater than the diameter of the aperture 76 so that the cover portion 80 normally covers or blocks the aperture 76 formed in the disk member 72. Due to the cover portion 80 being retained to the disk 74 by only a small hinge-like tab 82, upon experiencing a pressure force being applied to the cover portion 80 from the direction of the aperture 76, the cover portion 80 is free to move from its full-line position to its phantom line position wherein flow through the aperture 76 and C-shaped opening 78 is permitted. In contrast, however, due to the cover portion 80 being normally biased tightly against the disk 72, a pressure force being applied to the cover member 80 in an opposite direction causes the cover member 80 to be pressed more tightly against the disk 72 and thereby prevent any flow through the aperture 76 and across the valve 70. The valving members 70 are positioned adjacent opposite ends of the chemical bed sleeve 14 and are oriented so that the cover portion 80 is on the downstream side of intended flow through the housing 12 thereby insuring that flow through the housing can only be accomplished in one direction away from the mouth piece portion 22.

The end caps 16 and 18 are both formed having a generally cup-shaped configuration with the interior diameter 90 of the cap 18 being sized to be slightly less than the outside diameter of the distal end 28 of the housing 12 so that a slight interference fit exist to retain the cap 18 upon the distal end 28. In contrast to the cap 18, the end cap 16 includes an axially extending tapered shank portion 92 which is sized to be received and seal against the distal portion of the aperture 26 formed within the mouth piece portion 22 of the housing 12. As will be recognized, both of the end caps 16 and 18 are designed to remain upon the housing 12 during storage; however, may be easily readily removed from the housing 12 prior to use of the device 10 for analysis purposes.

Due to the high reactivity of the potassium dichromate impregnated silica gel compound 62, it is an important feature of the present invention that the housing 12, chemical bed sleeve 14, screens 50, and end caps 16 and 18 be formed of a material .inert to the potassium dichromate impregnated silica gel compound 60. In addition, due to this silica gel compound 60 posing a significant hazard to users, it is important that the particular material utilized for the housing 12 possesses sufficient impact sheer and tensile strength to positively prevent any accidental breakage during use. Further, due to the device 10 being preferably disposable in nature, the particular material utilized for the housing components of the device 10 must additionally be capable of economical high production fabrication.

Through extensive research, the present applicants have found that the vast majority of polymeric compounds release esters which react with the potassium dichromate impregnated silica gel compound 60 and, hence, are unsuitable for use in the disposable breath analyzer 10. Similarly, such polymeric materials which include ketones, esters, and/or other organic compounds found in mold release agents additionally are highly reactive to potassium dichromate impregnated silica gel. As such, the specific polymeric compound utilized in the present invention must be devoid of any organic compounds utilized for mold release agents, ketones, and esters. In addition, such chemical compounds should have high impact capacity to be capable of withstanding impact strength requirements for such a device.

Although various compounds exist, the applicant has found that medical grade polycarbonate and/or polypropylene specifically manufactured without any organic mold release compounds, possess the necessary properties (i.e. does not contain organic compounds, ketones, esters, or peroxides) so as to be the preferred candidates for the application. In addition, such polycarbonate and polypropylene polymeric materials may be economically fabricated by way of mass production extrusion and/or molding techniques. Thus, in the preferred embodiment, the main body portion 20, mouth piece portion 22, chemical bed sleeve 14, screen 50, valving members 70, and end caps 16 and 18 are all fabricated from polycarbonate material so as to insure user safety and prolong shelf life of the device 10.

The above-referenced individual components of the device are extruded or molded or in some instances, vacuum formed, without the use of mold release agents such that they will remain inert to the potassium dichromate impregnated silica gel. Once fabricated in this manner, the individual components are assembled by a novel method depicted in Figures 7 through 13. The initial step in the assembly method is depicted in Figure 7 wherein the chemical bed sleeve 14 is aligned in a vertical orientation and maintained in this orientation by cooperation of a suitable clamping means such as a caliber 100 extending within the registry recess or shoulder 101 formed adjacent the distal end of the chemical bed sleeve 14. A first screen 50A may then be inserted axially upward in the central aperture 40 of the chemical bed sleeve 14 from its phantom line position to its full line position. A quantity 64 of nonindicating silica gel may then be inserted from the upper end of the chemical bed sleeve 14 and the second screen 50B may be inserted axially downward within the aperture 40 from its phantom to full line position. As will be recognized, with the screens 50A and 50B positioned within the central aperture 40, the quantity 64 of nonindicating silica gel is maintained in precise axial orientation within the interior of the chemical bed sleeve 14. Subsequently, a quantity 62 of potassium dichromate impregnated silica gel may be inserted from the upper end of the chemical bed sleeve 14 with a third screen 50C being axially positioned within the aperture 40 in an analgous manner. Finally, a quantity of indicating desiccant 60 may additionally be inserted in the aperture 40 and the final screen 50D be inserted within the aperture 40. As will be recognized, due to the outside diameter of the screens 50A through 50D being slightly greather than the inside diameter of the central aperture 40, when positioned in such a manner, the axial location of the quantities 60, 62, and 64 are maintained or fixed within the chemical bed sleeve 14. In addition, due to the high reactivity of the potassium dichromate impregnated silica gel 62, the placement of the quantities of gel 62 is accomplished in an extremely low humidity environment of approximately no greater than 30 percent or less than one percent relative humidity and additionally is accomplished in an extremely rapid process as by way of automated equipment.

With the chemical bed sleeve 14 being filled with the quantities 60, 62 and 64 as defined above, the main body portion 20 of the housing 12 is preferably registered in a vertical orientation and the first valving member 70A may be inserted within the central aperture 24 of the body portion 20 from its phantom line position to its full line position. As will be recognized, the first valving member 70A is oriented such that its cover portion 80A is closer to the distal end 28 of the main body portion 20 then its central aperture 76A. In addition, the axial position of the first valving member 70A is located by abutment of the valving member 70A with the shoulder tab 34 formed adjacent the distal end 28 of the main body portion 20.

With the valving member 70A positioned within the aperture 24, the previously filled chemical bed sleeve 14 may be axially inserted within the interior of the aperture 24 to an axial position wherein its lowermost end directly abuts the valving member 70A. Due to the chemical bed sleeve 14 including the pair of circumferentially extending ribs 42 about its outside diameter, it will be recognized that when positioned within the main body portion 20, a seal is developed between the chemical bed sleeve 14 and main body portion 20. Subsequently, a second valving member 70B oriented in an analgous manner to the valving member 70A may be inserted within the the aperture 24 so as to directly abut the uppermost end of the chemical bed sleeve 14. The mouthpiece portion 22 of the housing 12 may be inserted within the aperture 24 to contact the second valving member 70B and is retained in position by either a laser weld or spin weld As will be recognized, the entire assembly of the chemical bed sleeve 14 valving members 70 and housing portions 20 and 22 is accomplished without the use of any adhesives which could possibly react to the quantity 62 of potassium dichromate impregnated silica gel compound.

With the housing 12 being assembled in such a manner, an inert gas such as nitrogen or argon, free of oxygen and organic contaminants, is applied through the distal end of the mouthpiece portion 22 of the housing 12 to flow through the aperture 26, chemical bed sleeve

OMPI 14, and openings 30. As will be recognized, this positive pressure of inert gas has the effect of purging any moisture, oxygen or other contaminants contained within the housing 12 and the quantity 62 of potassium dichromate impregnated silica gel that may have entered therein during assembly of the device 10. With the positive pressure existing within the interior of the device 10, the end caps 16 and 18 may be placed on the distal ends of the housing 12 to in effect ^' capture a quantity of the inert gas within the housing 12 and isolate the interior housing 12 from the external environment. A suitable packaging material such as a cellophane bag or envelope 120 may then be inserted over the entire assembly, a moderate vacuum may be drawn between the bag and the housing, and the bag may be subsequently sealed at opposite ends to form an hermetically sealed environment devoid of any oxygen, moisture, or organic compounds around the housing 12. Due to the assembled device 10 being completely devoid of any oxygen or moisture contaminants as well as having a positive pressure of inert gas existing within the interior of the housing 12, prolong storage or shelf life of the device 10 is insured.

With the structure and method of assembly being defined, the operation of the disposable breath analyzer 10 of the present invention may be described. Due to its relatively small size (i.e. approximately one-half inch in diameter by four inches in length), the analyzer 10 may be easily carried by a user. When it is desired to obtain a blood alcohol concentration level of an individual, a user need only rupture the cellophane envelope sealed about the housing 12 and remove the end cap 16 and 18 from the housing 12. The mouthpiece portion 22 of the housing 12 may then be inserted into the mouth of the user and the user may exhale preferably two quantities of air through the mouthpiece each for ten second intervals.

Due to the pressure of the breath sample, the valving members 70A and 7OB move from their full line position to their phantom position (as indicated in Figure 1) to allow the breath sample to enter into and pass through the quantity 62 of potassium dichromate impregnated silica gel as well as the quantity 60 of desiccant and 64 of nonindicating silica gel contained within the chemical bed sleeve 14. As the breath sample passes through the quantity 62, the alcohol contained within the breath sample is absorbed or scrubbed causing the quantity of potassium dichromate impregnated silica gel to change from its initial color to a subsequent indicator color. The scrubbing properties of the silica gel 62 are such that the color change is linear and proportional to the amount of alcohol absorbed by the impregnated silica gel. As such, for a given volume of air sample (i.e. approximately one liter of air), a linear change in color of the quantity of gel .62 will be provided. After the sample has been blown through the housing, the user may visually inspect the quantity of gel 62 by viewing through one of the window openings 32 formed in the main body portion 20 of the housing 12 and note the axial length of color change of the gel 62 upon the scaled indicia 122 formed on the main body portion 20 of the housing 12. The indicia is calibrated for blood alcohol level and, hence, an indication of the actual blood alcohol concentration of the individual can be obtained. Upon completion of the viewing, the entire housing 12 may be discarded or alternatively maintained for future reference or evidentiary purposes.

As will be recognized, due to the inclusion of the valving members 70A and 70B on opposite sides of the chemical bed sleeve .14, back aspiration of quantity of

OMPI air through the housing 12 is eliminated. In addition, these valving members preferably form a sufficiently tight seal such that the quantity of silica, gel 62 is isolated from the exterior of the housing even if the device 10 is accidentally dropped into a user's drink. In addition, due to the housing 12 being formed of high impact strength polymeric material, any accidental breakage of the device 10 is substantially eliminated and access to the quantity of silica gel material 62 is eliminated except through purposeful unauthorized conduct by a user.

Although for purposes of description certain sizes and configurations have been assigned, those skilled in the art will recognize that modifications to the same can be made without departing from the spirit of the present invention, and such modifications are clearly contemplated herein.

OMPI

Claims

WHAT IS CLAIMED IS:

1. A portable breath analyzer device comprising: a housing having a first portion adapted to be placed in the mouth of a user and a second portion positioned for flow communication with said first portion; and a quantity of colorimetric material contained within said second portion of said housing adapted to change color in response to the presence of alcohol carried by a breath sample initiated through said housing; said housing formed of a polymeric compound substantially devoid of ketones, esters, and organic mold release compounds so as to be generally inert with respect to said quantity of colorimetric material.

2. The device of claim 1 wherein said quantity of colorimetric material comprises a quantity of potassium dichromate impregnated silica gel.

3. The device of claim 2 further comprising valve means positioned within said second portion of said housing on opposite sides of said quantity- of potassium dichromate impregnated silica gel for allowing flow of the breath sample initiated through said housing in only one direction.

4. The device of claim 3 wherein said valve means are formed of a polymeric compound substantially devoid of ketones, esters and organic mold release compounds.

5. The device of claim 4 wherein said polymeric compound is substantially devoid of ketones, ester and organic mold release compounds comprises polycarbonate.

6. The device of claim 4 wherein said

OMPI polymeric compounds substantially devoid of ketones, esters and organic mold release compounds comprises polypropylene.

7. A disposable breath analyzer device comprising: a tubular housing having a first portion adapted to be placed in the mouth of a user and a second portion in flow communication with said first portion; a colorimetric material disposed within said second portion of said housing adapted to change color in response to the presence of alcohol carried by a breath sample blown through said housing; a quantity of inert gas captured within the interior of said housing to isolate said colorimetric material from any contaminants reactive to said colorimetric material; and indicia positioned relative said " colorimetric material to indicate the percent ratio of blood alcohol content in the breath sample blown through said housing.

8. The device of claim 7 further comprising valve means disposed within said second portion of said housing on opposite sides of said colorimetric material for allowing passage of the breath sample in only one direction through said housing.

9. The device of claim 8 further comprising a pair of end caps releasably mounted on opposite ends of said housing and adapted to retain said quantity of inert gas captured within the interior of said housing.

10. The device of claim 9 wherein said housing and pair of end caps are formed of a polymeric material substantially inert with respect to said colorimetric material.

11. The device of claim 10 wherein said colorimetric material comprises a potassium dichromate impregnated silica gel.

12. The device of claim 11 wherein said polymeric material comprises a polymeric material devoid of any ketones, esters and organic mold-release compounds.

13. The device of claim 12 wherein said polymeric compound comprises polycarbonate.

14. The device of claim 12 wherein said polymeric compound comprises polypropylene.

15. A method of fabricating a disposable breath analyzer device comprising the steps of: forming a tubular housing having a first portion adapted to be inserted within a mouth of a user; and a second portion sized to store a quantity of colorimetric material; filling said second portion of said housing with a quantity of colorimetric material; applying an inert gas through the interior of said housing to purge any moisture and contaminants from the interior of said housing and said quantity of colorimetric material; and capturing a quantity of said inert gas within the interior of said housing to isolate said colorimetric material from any environmental contaminants.

16. The method of claim 15 wherein said filing step comprises filing said second portion of said housing with a quantity of potassium dichromate impregnated silica gel within a reduced humidity environment of not greater than 30 percent relative humidity and not less than 1 percent relative humidity.

17. The method of claim 16 wherein said forming step comprises forming said housing of a polymeric

OMPI material substantially inert with respect to said postassium dichromate impregnated silica gel.

18. The method of claim 17 wherein said capturing step comrpises placing a pair of end caps on opposite ends of said housing.

19. The method of claim 18 comprising the further step of enclosing said housing and said end caps in an envelope to form a hermetically sealed environment about said housing.

20. The method of claim 19 comprising the further step of evacuating the interior of said envelope about said casing.

21. The method of claim 20 wherein said forming step comprises forming said housing of a polymeric material substantially devoid of ketones, esters, and organic mold release agents.

22. The method of claim 21 wherein said forming step comprises forming said housing of polycarbonate.

23. The method of claim 22 wherein said forming step comprises forming said housing of polypropylene.