WO1997006428A1

WO1997006428A1 - Handheld liquid test device

Info

Publication number: WO1997006428A1
Application number: PCT/US1995/010278
Authority: WO
Inventors: Brent W. Poole; David A. Holcombe
Original assignee: Poole Brent W; Holcombe David A
Priority date: 1995-08-10
Filing date: 1995-08-10
Publication date: 1997-02-20
Also published as: AU3323495A

Abstract

A handheld liquid test (10) device includes an elongated syringe barrel (11) defining a nozzle (13) and frontal chamber (14) and an open end. A semi-cylindrical scale carrier (50) supports a test scale (60) and is received within the interior bore (12). An elongated plunger shaft (31) extends into the syringe barrel bore (12) beyond the scale carrier (50). A resilient piston seal (40) is removably secured to the interior end of the plunger shaft (31) and defines a wiping aperture (44) extending therethrough.

Description

HANDHELD LIQUID TEST DEVICE

SPECIFICATION

Cross-Reference to Related Patent Applications

This application is a continuation-in-part of a copending application filed April 16, 1992 in the names of David A. Holcombe and Brent . Poole having serial number 07/869,452 and entitled INTEGRAL CATHETER AND BLOOD TESTER which is hereby incorporated herein by reference.

Field of the Invention

This invention relates generally to liquid test apparatus and particularly to liquid test apparatus utilizing an immersible test strip or similar article.

Background of the Invention

In a variety of medical, environmental and commercial environments, a need arises to perform various tests of the chemical and physical properties of liquids while avoiding exposure thereto. For example, in the medical arts, medical practitioners often perform tests upon body fluids such as blood or urine to determine various characteristics. One of the most common tests performed upon blood by medical practitioners involves determination of the blood glucose or blood sugar level of the patient. In addition, other tests are performed to determine properties such as the pH of blood as well as various cell count characteristics such as white blood cell count to determine the existence of conditions such as infections or the like. Similar tests may be performed upon urine also, for example, to detect the presence of blood within the urine indicating a trauma within the system or protein level to indicate kidney or liver function or test for ketones to determine diabetic ketoacidosis. A variety of other tests are routinely performed upon patient's blood and urine as well as other body fluids. Such tests are, of course, performed upon humans and animals as well for similar purposes.

Because many diseases and illnesses are carried by body fluids such as blood or urine, medical practitioners must be careful in their procedures and must take steps to be protected from contracting such diseases and illnesses by exposure to the body fluids. Often, practitioners wear precautionary clothing articles such as surgical gloves and gowns as well as masks or the like. However, many medical technicians and practitioners are called upon to operate in high stress critical emergency situations such as combat medical facilities, emergency rooms, accident scenes, or sites of natural disasters. Under these extreme conditions, careful gowning and maintenance of gloves and masks may not always be practical. In addition, the integrity of such protective clothing and other articles may be compromised by hazards at the operational site. For example, surgical gloves are easily punctured or torn when exposed to fractured materials such as splintered wood or torn metal which often are plentiful at such emergency medical situations.

Another example of potentially hazardous exposure to liquids during testing occurs in the monitoring and testing of hazardous materials or hazardous wastes. Here again, careful procedures and the use of gloves and protective clothing or the like may not always be available or their integrity may be compromised by operational difficulties at the site.

Faced with the continued need to effectively test various liquids which are potentially hazardous to the tester, there arises therefore a need in the art for a liquid test device which protects the user from exposure to the liquid under test without unduly encumbering the effectiveness or operational capability of the user.

Summary of the Invention

Accordingly, it is a general object of the present invention to provide an improved liquid test device. It is a more particular object of the present invention to provide an improved liquid test device which protects the user from exposure to the liquid during the test procedure and thereafter. It is a still more particular object of the present invention to provide a liquid test device which may be handheld and manipulated easily in the hands of a user.

In accordance with the present invention, there is provided a liquid test device comprises: a body defining an interior bore, a liquid receiving end, and an open end; a plunger shaft having a first end extending into the bore and a second end beyond the open end; a piston seal removably attached to the first end of the plunger shaft and defining a wiper aperture; an elongated test strip supporting a test material coupled to the first end of the plunger shaft and extending through the wiper aperture and beyond the piston seal; stop means supported by the body operating as the plunger shaft is moved outwardly through the open end to limit the movement of the piston seal at a stop point within the bore; and a test scale supported by the body between the stop point and the open end. Brief Description of the Drawings

The features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in the several figures of which like reference numerals identify like elements and in which:

Figure 1 sets forth a section view of a liquid test device constructed in accordance with the present invention;

Figure 2 sets forth a section view of the present invention liquid test device taken along section lines 2- 2 in Figure 1;

Figure 3 sets forth a section view of the present invention liquid test device taken along section lines 3- 3 in Figure 1;

Figure 4 sets forth a section view of the present invention liquid test device at the test strip immersion stage of the testing process;

Figure 5 sets forth a section view of the present invention liquid test device at the test strip evaluation stage of the testing process;

Figure 6 sets forth a partial section view of an alternate embodiment of the present invention liquid test device; Figure 7 sets forth a partial section view of a further alternate embodiment of the present invention liquid test device;

Figure 8 sets forth a partial section view of a still further alternate embodiment of the present invention liquid test device;

. Figure 9 sets forth a perspective assembly view of a portion of the present invention liquid test device;

Figure 10 sets forth a partial section view of the test strip attachment mechanism of the present invention liquid test device;

Figure 11 sets forth a partial section view of an alternate test strip attachment mechanism of the present invention liquid test device;

Figure 12 sets forth a partial section view of a still further alternate test strip attachment mechanism of the present invention liquid test device;

Figure 13 sets forth a section view of an alternate embodiment of the present invention liquid test device taken along section lines 13-13 in Figure 4; and

Figure 14 sets forth a section view of a still further alternate embodiment of the present invention liquid test device taken along section lines 3-3 in Figure 1.

Description of the Preferred Embodiments

Figure 1 sets forth a section view of a liquid test device fabricated in the general form of a syringe and generally referenced by numeral 10. It should be noted at the outset that while the present invention liquid test device is conveniently fabricatable using a syringe structure, other structures may be utilized without departing from the spirit and scope of the present invention. Syringe 10 includes a generally cylindrical syringe barrel 11 defining an internal cylindrical bore 12 and an outwardly extending flange 17. Syringe barrel 11 further defines a tapered portion 13 and a forwardly extending frontal chamber 14. Frontal chamber 14 is coupled to a tapered nose portion 15 having a passage 16 defined therein. Passage 16, frontal chamber 14 and internal bore 12 communicate to form a continuous internal passage for syringe 10. An elongated semicylindrical scale carrier 50 defines an end 52 and an outwardly extending flange 51 and is configured to be precisely received within internal bore 12 and conforms generally thereto. In its preferred form, syringe barrel 11 is fabricated of a transparent plastic material. Scale carrier 50 is preferably formed of a molded plastic material and thus is receivable within syringe barrel 11 and secured therein using conventional fabrication techniques such as adhesive bonding, heat staking or ultrasonic welding or their equivalent. The important aspect is the secure attachment of scale carrier 50 within syringe barrel 11 in the manner shown in Figure l. As is better seen in Figure 3, scale carrier 50 further defines a pair of oppositely positioned elongated guides 55 and 56 extending the length of scale carrier 50. Scale carrier 50 further defines a lip 53 proximate flange 51 and continuous therewith.

An elongated plunger 30 includes a cruciform-shaped plunger shaft 31 having a quartet of mutually perpendicular ribs 33, 34, 35 and 36. Plunger 30 further includes a knob 32 at the outer end of plunger shaft 31 and a generally planar end plate 37 at the interior end thereof. As is better seen in Figure 9, end plate 37 further defines a pair of opposed notches 26 and 27 which receive guides 55 and 56 of scale carrier 50 and facilitate the insertion of plunger 30 into scale carrier 50. By means set forth below in greater detail, plunger 30 supports a resilient piston seal 40 having a pair of spaced apart seal rings 41 and 42 sized to fit sealingly within internal bore 12 of syringe barrel ll. Piston seal 40 further defines a cone-shaped portion 43 conforming generally to tapered portion 13. In accordance with an important aspect of the present invention and as is described below in greater detail, syringe 10 further includes an elongated generally planar test strip 60 having an elongated generally rectangular relatively rigid substrate 61 supporting a pair of test patches 62 and 63. By means also set forth below in greater detail, substrate 61 of test patch 60 extends through a wiper slot 44 (seen in Figure 9) formed within piston seal 40 and is secured to plunger 30. Thus, by means set forth below in greater detail, test strip 60 is secured to the interior end of plunger 30 and extends through piston seal 40 and into frontal chamber 14.

Figure 2 sets forth a section view of syringe 10 taken along section lines 2-2 in Figure 1. As described above, syringe 10 includes a generally cylindrical syringe barrel defining a tapered portion 13 and a frontal chamber 14. A test strip 60 is supported by plunger 30 and extends into frontal chamber 14. Syringe barrel 11 further defines an outwardly extending circular flange 17. In accordance with the liquid test process set forth below in greater detail, frontal chamber 14 is preferably formed to conform generally to the rectangular cross-section of test strip 60 rather than being fully cylindrical. The function of this shape for frontal chamber 14 provides a maximum of exposure of test strip 60 and test patches 62 and 63 thereon using a minimum of fluid within frontal chamber 14. As a result, a small amount of liquid within frontal chamber 14 completely immerses test strip 60 increasing its efficiency and avoiding needless waste of the liquid being tested.

Figure 3 sets forth a section view of syringe 10 taken along section lines 3-3 in Figure 1. As described above, syringe 10 includes a cylindrical syringe barrel 11 defining an internal bore 12 and an outwardly extending circular flange 17. Scale carrier 50 defines a semicylindrical member received and secured within internal bore 12 of syringe barrel 11. Scale carrier 50 further supports a semicylindrical scale 54 which is printed or otherwise formed upon the interior surface of scale carrier 50. A pair of elongated guides 55 and 56 are supported within the interior of scale carrier 50 and extend inwardly to assist in positioning a cruciform- shaped plunger shaft 31 within internal bore 12 and scale carrier 50.

In the position shown in Figure 1, syringe 10 is configured to begin a liquid test process in that plunger 30 is positioned forwardly extending fully into syringe barrel 11 and test strip 60 extends into frontal chamber 14. Thus, in a typical testing procedure, nose 15 of syringe barrel 11 is coupled to a source of liquid to be tested. For example, in the event an open vessel or other supply of liquid is to be tested, the user simply dips nose 15 into the to-be-tested liquid and draws plunger 30 outwardly from syringe barrel 11 in the direction indicated by arrow 20. If, on the other hand syringe 10 is used to test a blood sample for example, nose 15 may be coupled to a conventional intravenous cannula by simple insertion of nose 15 and thereafter drawing plunger 30 outwardly in the direction indicated by arrow 20. The important aspect of this initial step in the use of syringe 10 is the coupling of nose 15 either directly or indirectly to a source of liquid to be tested followed by an initial drawing motion of plunger 30 in the direction indicated by arrow 20. The initial drawing motion of plunger 30 results in moving piston seal 40 correspondingly which in turn produces a partial vacuum within frontal chamber 14 and internal bore 12 drawing the to-be-tested liquid through passage 16 into frontal chamber 14 and internal bore 12.

Figure 4 sets forth a section view of syringe 10 showing the completion of the sample drawing process in which plunger 30 has been drawn outwardly from syringe barrel 11 until piston seal 30 is brought into contact with end 52 of scale carrier 50. At the point of operation shown in Figure 4, the drawing motion of plunger 30 has drawn the to-be-tested liquid through passage 16 into frontal chamber 14 and internal bore 12 of syringe barrel 11. Most importantly to the present invention, the in-flow of to-be-tested liquid results in exposing test patches 62 and 63 of test strip 60 to the liquid under test. As described above, test patches 62 and 63 may utilize virtually any test material such as that commonly utilized for blood glucose level determinations in blood testing. It will be apparent, however, that virtually any test patch material may be used for test patches 62 and 63 without departing from the spirit and scope of the present invention. Thus, in the event a hazardous liquid is being tested, test patches 62 and 63 may comprise an indicator material which utilizes virtually any of the available test strip chemistries in which the test strip material undergoes a visible change such as change of color or luminance value when exposed to a to-be-tested liquid. For example, the familiar use of litmus material for determining the pH of a liquid undergoes a color change in response to the acid or base ion content of the liquid. A virtually endless variety of test materials are available, many of which undergo color changes in response to the to-be-tested property. This chemistry has been found extremely advantageous in a variety of liquid testing and is by no means limited to blood testing or testing of body fluids for that matter.

With the exposure of test patches 62 and 63 of test strip 60 to the liquid under test following the drawing motion from the configuration of Figure l to that shown in Figure 4, the user then waits the predetermined time interval for reaction of the test patch material to the liquid while maintaining syringe 10 in the position shown in Figure 4.

Figure 5 sets forth syringe 10 during the final step in the use of the present invention liquid test device. As described above, syringe 10 includes a cylindrical syringe barrel 11 defining an internal bore 12, a tapered portion 13, a frontal chamber 14 and a nose portion 15 which in turn defines a passage 16. Syringe barrel 11 further defines an outwardly extending flange 17. Syringe 10 further includes a semicylindrical scale carrier 50 received within internal bore 12 and secured therein by conventional attachment process. Scale carrier 50 includes a flange 51 secured to flange 17 and an internal end 52. Scale carrier 50 further includes a lip 53 proximate flange 51 and in accordance with an important aspect of the present invention supports a cylindrically shaped visible scale 54 on the interior surface of scale carrier 50. Scale 54 is painted or printed or otherwise caused to bear a visual comparison scale for use in evaluating the liquid under test based upon comparison of standard test indicia. Such comparison scales are well known in the art and may, for example, comprise a plurality of elements having color variation corresponding to particular values of the to- be-tested property together with the associated numeric values for use in quantifying the characteristic of the liquid under test. For example, in the test of pH value of a liquid, the typical litmus test material varies from a deep magenta color to a yellow color in response to the pH of the liquid. Similar color related indicia are provided on scales such as scale 54 to be utilized in testing blood sugar levels or the presence of other chemicals under test. The important aspect for the present invention is that scale 54 is supported within the interior of syringe barrel 11 and is viewed through the transparent plastic material from which syringe barrel 11 is fabricated.

Plunger 30 defines a cruciform-shaped plunger shaft 31 having a plurality of quadature related ribs 33 through 36 and an end knob 32. Plunger 30 further includes a generally planar end plate 37 at the interior end thereof having a strip attachment plate 39 extending beyond plate 37. Strip attachment plate 39 further includes a generally rectangular tab 38 and a pair of outwardly extending ears 28 and 29. A test strip 60 includes an elongated substrate 61 supporting a pair of test material patches 62 and 63 and defines an elongated slot 64. Slot 64 is received upon tab 38 of strip attachment plate 39 to secure test strip 60 in the position shown in Figure 5.

Syringe 10 further includes a piston seal 40 having a pair of seal rings 41 and 42 and a cone-shaped portion 43. As is better seen in Figure 10, piston seal 40 defines an interior cavity 45 receiving end plate 37 of plunger 30 and an elongated wiper slot 44 through which substrate 61 of test strip 60 extends.

In operation and with temporary reference to Figure 4, the drawing motion of plunger 30 in the direction of arrow 20 brings piston seal 40 up against end 52 of scale carrier 50 during the drawing process of liquid testing.

SUBSTITUTESHEET(RULE26 Once piston seal 40 is brought against end 52 of scale carrier 50 and the user waits the predetermined time interval for exposure of test patches 62 and 63, the user then draws plunger 30 an additional distance in the direction indicated by arrow 20 to the configuration shown in Figure 5. In accordance with an important aspect of the present invention as the user draws plunger 30 an additional distance in the direction indicated by arrow 20, strip attachment plate 39 is pulled from interior cavity 45 (seen in Figure 10) due to the interference of end 52 of scale carrier 50 and piston seal 40 which precludes further movement of piston seal 40. As strip attachment plate 39 is pulled from interior cavity 45 of piston seal 40, test strip 60 is correspondingly drawn through wiper slot 44 (also seen in Figure 10) of piston seal 40. The resilience of material used in fabricating piston seal 40 and the narrow width of wiper slot 44 causes piston seal 40 to wipe test strip 60 clean of the liquid under test as test strip 60 is drawn through wiper slot 44. Once test strip 60 has been drawn completely through piston seal 40, piston seal 40 remains at the position shown in Figure 5 while test strip 60 is freely movable in the region of scale 54 by movement of plunger 30 back and forth in the directions indicated by arrows 21. In further accordance with an important aspect of the present invention, test patches 62 and 63 upon test strip 60 have at this point been fully exposed to the liquid under test and cleaned of all excess liquid and thus may now be observed through the transparent material of syringe barrel 11 for comparison to scale 54. This comparison process is rendered easier in that plunger 30 may be used to move test strip 60 with respect to scale 54 aligning test patches 62 and 63 with the standard value portions of scale 54. Once the user has through manipulation of plunger 30 performed this comparison, the user simply then reads the appropriate corresponding number to the standard indicator upon scale 54 and completes the liquid test.

In accordance with an important aspect of the present invention, it should be noted that the entire liquid test process is performed without exposing the user to the liquid being tested. The liquid is maintained within internal bore 12 and frontal chamber 14 of syringe barrel 11 and need not be handled by the user. The entire liquid test device is disposable and may simply be discarded following its use in accordance with accepted methods of waste disposal for the material having been tested.

It will be apparent to those skilled in the art that while the example of the present invention liquid test device set forth in Figures through 5 utilizes a test strip having a pair of test patches, a substantial variation of the number and shape of test strip patches used on the test strip are well within the spirit and scope of the present invention.

Figures 6, 7 and 8 set forth alternate embodiments of the present invention liquid test device each utilizing a one-way valve apparatus coupled to or integral with the present invention liquid test device to prevent liquid drawn into the test device from returning to the sampling area. This aspect is particularly important in applications within the medical arts in which a sterilized cannula or the like is coupled to the liquid test device due to the difficulty in providing test strip materials which may survive the sterilizing process. In such medical environments, it has been found that the sterilizing process if applied to the entire liquid test device often damages or destroys the material used on the test strip. To facilitate the use of an unsterilized or unsterilizable syringe in such medical environments in particular, a one-way valve structure in employed which permits the body fluid to be drawn into the test device but prevents a return flow of body fluid from the unsterilized test patch back into the patient's body. It will be apparent, however, that while this one¬ way valve alternate embodiment is highly desirable in certain medical applications, it may find application equally well in other environments such as those described above.

More specifically. Figure 6 sets forth a partial section view of a syringe generally referenced by numeral 70. Syringe 70 includes a generally cylindrical syringe barrel 71 substantially identical to syringe barrel ll set forth above in Figures 1 through 4 with the difference being the shape of frontal chamber 75 being substantially different than frontal chamber 14 thereof. The remainder of syringe barrel 71, however, is identical to syringe barrel 11 shown above and should be understood to include a scale carrier 50 assembled in the manner described above. By way of further similarity, plunger 30 and piston seal 40 also identical to that set forth above are received within syringe barrel 71. As described above, plunger 30 supports an elongated rectangular test strip 60 in the manner described above. Test strip 60 extends into frontal chamber 75. Frontal chamber 75 receives and supports a one-way valve 78 fabricated in accordance with the conventional "duck bill" type construction in which a slit 79 extends transversely across the interior portion of valve 78. Frontal chamber 75 defines an end 76 coupled to a nosepiece 77. Nosepiece 77 is configured to alternatively be coupled to a conventional cannula or the like or may be simply used to aspirate a liquid under test in the manner described above. In operation, syringe 70 is utilized in the same manner described above for syringe 10 in that nose 77 is coupled to a source of liquid to be tested and plunger 30 is withdrawn from syringe barrel 71 drawing liquid into frontal chamber 75. During this drawing process, valve 78 opens at slit 79 permitting liquid to flow through valve 78 into frontal chamber 75 and syringe barrel 71. In the absence of a drawing action by plunger 30, however, valve 78 closes and seals frontal chamber 75 preventing a return flow of liquid from frontal chamber 75 through nosepiece 77 thereby preventing contamination of the liquid source such as a patient's blood supply or the like.

Figure 7 sets forth a further alternate embodiment of the present invention liquid test device in which a conventional check ball type valve apparatus generally referenced by numeral 80 is secured to a frontal chamber 81 of an otherwise identical syringe 90. Thus, syringe 90 functions in the same manner described above and differs from the above-described embodiments in that frontal chamber 81 thereof receives valve 80.

In operation as piston seal 40, plunger 30 and test strip 60 are drawn in the direction indicated by arrow 20, the liquid under test is drawn into valve body 82 of valve 80 moving check ball 83 away from valve seat 84.

Thus, the liquid under test flows freely past check ball 83 into frontal chamber 81 in the manner described above. Once the drawing motion of plunger 30 is complete, however, the flow of liquid outwardly through valve 80 is precluded by the movement of check ball 83 against valve seat 84 within valve body 82.

Figure 8 sets forth a partial section view of a still further alternate embodiment of the present invention generally referenced by numeral 100. Syringe 100 includes a syringe barrel 101 identical to syringe barrel 11 set forth above with the difference being a forwardly extending frontal chamber 102 which receives a conventional "umbrella" valve 110. Umbrella valve 110 is fabricated of a flexible material and responds to drawing motion of plunger 30 in the direction indicated by arrow 20 by flexing flap 111 away from seat 112 to permit liquid flow through nose 103 into frontal chamber 102. Conversely, in the event plunger 30 is moved inwardly, the liquid force against flap 111 returns flap 111 to a sealing position against seat 112 and prevents return flow of the liquid under test.

It will be apparent to those skilled in the art that a variety of additional one-way check valve type structures may be utilized in combination with the present invention liquid test device to accomplish the basic function described in Figures 6, 7 and 8 without departing from spirit and scope of the present invention.

Figure 9 sets forth a perspective assembly view of the test strip, piston seal, and plunger attachment of the present invention liquid test device. Plunger 30 includes a cruciform-shaped plunger shaft 31 having a plurality of ribs 33 through 36 and a planar end plate

37. End plate 37 defines a pair of opposed notches 26 and 27. Plunger 30 further includes a generally planar strip attachment plate 31 having a pair of outwardly extending ears 28 and 29 and an upwardly extending tab

38. Piston seal 40 is generally cylindrical in shape and defines a pair of annular seal rings 41 and 42 and a cone portion 43. An elongated wiper slot 44 is formed in cone portion 43 and defines a chamfered surface 46. As is better seen in Figure 10, piston seal 40 further defines an interior cavity 45 having a groove 124 formed therein. A test strip 60 includes an elongated generally rectangular substrate 61 having a pair of bevel surfaces 65 and 66 and a rectangular slot 64 at one end thereof. Substrate 61 supports a pair of test patches 62 and 63 formed of a liquid test material.

Test strip 60 and piston seal 40 are assembled to plunger 30 by initially passing the beveled end of test strip 60 through wiper slot 44 of piston seal 40 and beyond piston seal 40 to place the end of test strip 60 upon strip attachment plate 61 of plunger 30 such that tab 38 is received within slot 64. Slot 64 is preferably sized to fit securely upon tab 38 and avoid the need for further assembly operation in securing test strip 60 to strip attachment plate 31. Alternatively, however, in the manner set forth below in Figure 11, tab 38 may be heat staked or otherwise deformed to secure test strip 60 to attachment plate 31. In addition, the use of chamfered surface 46 and bevels 65 and 66 of test strip 60 facilitate the insertion of test strip 60 through wiper slot 44 of piston seal 40. Once test strip 60 has been secured to attachment plate 31, piston seal 40 is then forced upon attachment plate 31 deforming piston seal 40 temporarily and inserting ears 28 and 29 into groove 124 within interior cavity 45 of piston seal 40 (seen in Figure 10) . This completes the assembly process by which test strip 60, piston seal 40 and plunger 30 are combined.

Figure 10 sets forth an alternate embodiment of the present invention utilizing an alternative attachment of test strip 60 and piston seal 40 to an alternatively configured plunger 120. Piston seal 140 defines a pair of seal rings 41 and 42 and a cone portion 43 as described above. Piston seal 40 further defines an elongated wiper slot 44 having a chamfered surface 46. An interior cavity 45 formed within piston seal 40 defines an annular groove 124. A plunger 120 having a cruciform-shaped plunger shaft 121 and an end plate 122 supports a strip attachment plate 123 defining a channel 127 and a tab 128. Test strip 60 includes a substrate 61 defining a slot 64 and a pair of test patches 62 and 63. Substrate 61 extends through wiper slot 44 and is received upon tab 128 at slot 64. The con iguration of Figure 10 differs from that shown in Figure 9 in that strip attachment plate 123 is generally orthogonal to slot 44 of piston seal 40 in the embodiment of Figure 10 while strip attachment plate 31 is generally parallel to wiper slot 44 in the embodiment of Figure 9. The operational functions of each, however, is the same as that set forth above in that the above-described test strip wiper action is achieved as piston seal 40 is stopped within the host syringe barrel and test strip 60 is drawn through wiper slot 44 of piston seal 40.

Figure ll sets forth a still further alternate embodiment of the present invention in which tab 128 of plunger 120 is deformed by heat staking or other fabrication techniques to further secure test strip 60 to attachment plate 123.

Figure 12 sets forth a still further alternate embodiment of the present invention in which the attachment of test strip 60 to attachment plate 123 is further enhanced by providing an offset or angled tab 129 to secure test strip 60.

Figures 13 and 14 set forth section views of still further alternate embodiments of the present invention in which the scale carrier utilizes a flexible planar scale insert as an alternative to the printing or painting process used to form scale 54 upon the interior surface of scale carrier 50 in the above-described embodiments in Figures 1 through 5. Thus with specific reference to Figure 13, syringe 10 includes a cylindrical body 11 defining an internal bore 12 within which a scale carrier 130 is received. Scale carrier 130 defines a semi¬ cylindrical member generally similar to scale carrier 50 set forth above and assembled within syringe barrel 11 in the manner also described above. Scale carrier 130, however, differs from scale carrier 50 in that a generally rectangular flexible scale insert 133 formed of a resilient material such as thin plastic or the like and having the standard visual indicia for use in the above- described testing process formed on the interior surface thereof. Scale insert 133 is inserted into scale carrier 130 by forcing scale insert 133 into the curved configuration shown and releasing scale insert 133 such that the scale insert is captivated between guides 131 and 132 of scale carrier 130 and maintained in position. The advantage of using scale insert 133 within scale carrier 130 is the ease with which different scales may be inserted within the present invention liquid test device to accommodate various types of liquid testers. In this manner, a standard scale carrier may be utilized with the appropriate scale provided by simply adding the desired scale insert.

Figure 14 sets forth a section view of a similar alternate embodiment of the present invention liquid test device. Thus, syringe 10 includes a cylindrical syringe barrel 11 defining an internal bore 12 within which a semicylindrical scale carrier 150 is secured. Scale carrier 150 includes a pair of opposed guides 151 and 153 and an inwardly extending center guide 152. A scale insert 154 similar to scale insert 133 forms an elongated generally rectangular flexible plastic member or the like upon which a suitable standard set of scale indicia are defined upon interior surface 155 thereof. The primary advantage of the embodiment of Figure 14 in addition to providing the above-described insertion of a variety of scale inserts within a common scale carrier is the increase of viewable angle provided by the less curved configuration of scale insert 44 as opposed to the nearly cylindrical curve of scale insert 133 of the embodiment shown in Figure 13. To accommodate the use of a less curved scale insert in the embodiment of Figure 14, a nonsymmetrical plunger 140 is utilized having a plunger shaft having three mutually perpendicular ribs 142, 143 and 144 extending from end plate 145. In all other respects, the embodiments of Figures 13 and 14 function in the manner described above and provide the above- described attachment of the respective plungers thereof to piston seal 40 and test strip 60 (seen in Figure 9) .

What has been shown is a liquid test device suitable for handheld use by users seeking to avoid intimate contact with the liquid under test. The liquid test device utilizes a syringe-like body within which a plunger and piston seal together with a test strip are slidably supported. An internal scale carrier supports a scale within the syringe body. The user is able to employ simple manipulation of the plunger to perform the initial aspiration of a quantity of the liquid under test into a test chamber within which the test strip is exposed to the liquid and thereafter in a further motion draw the test strip through the piston seal into an evaluation chamber. The drawing action moving the test strip into the evaluation chamber is provided with a test strip wiping action due to the unique configuration of the piston seal. With the exposed test strip moved into the comparison chamber, the user is able to move the test strip back and forth manipulating the plunger against the comparison scale. The entire process avoids any exposure of the user to contact with the liquid under test.

While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects. Therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.

Claims

THAT WHICH IS CLAIMED IS:

1. A liquid test device comprising:

a body defining an interior bore, a liquid receiving end, and an open end;

a plunger shaft having a first end extending into said bore and a second end beyond said open end;

a piston seal removably attached to said first end of said plunger shaft and defining a wiper aperture;

an elongated test strip supporting a test material coupled to said first end of said plunger shaft and extending through said wiper aperture and beyond said piston seal;

stop means supported by said body operating as said plunger shaft is moved outwardly through said open end to limit the movement of said piston seal at a stop point within said bore; and

a test scale supported by said body between said stop point and said open end.

2. A liquid test device as set forth in claim 1 wherein said test strip defines a plurality of test material patches and wherein said test scale defines a plurality of visually distinguishable elements.

3. A liquid test device as set forth in claim 2 wherein said body further includes a limit stop extending said bore proximate said open end, said limit stop preventing withdrawal of said first end of said plunger shaft from said interior bore.

4. A liquid test device as set forth in claim 3 wherein said test strip is generally planar and wherein said wiper aperture is an elongated slot.

5. A liquid test device as set forth in claim 4 wherein said body is formed of a generally transparent material and wherein said test scale is supported within said interior bore.

6. A liquid test device as set forth in claim 1 wherein said body is formed of a generally transparent material and wherein said test scale is supported within said interior bore.

7. A liquid test device as set forth in claim 6 wherein said body defines an interior surface surrounding said interior bore and wherein said test scale is formed on a portion of said interior surface.

8. A liquid test device as set forth in claim 6 further including a cylindrical scale carrier received within said interior bore and having a first edge forming said stop means and having a pair of elongated guides extending inwardly and wherein said test scale includes a planar sheet received within said scale carrier and captivated by said guides.

9. A liquid test device as set forth in claim 1 wherein first end of said plunger shaft defines a tab and wherein said test strip defines an aperture receiving said tab to couple said test strip to said first end of said plunger shaft.

10. A liquid test device as set forth in claim 1 further including a one-way valve coupled to said liquid receiving end of said body and oriented to permit liquid flow into said body and prevent liquid flow from said body.

11. A liquid test device comprising:

a body defining an interior bore, a liquid receiving end, an open end, and a test scale supported within said interior bore;

a plunger extending into said bore from said open end and movable within said bore;

a piston coupled to said plunger and movable within said bore defining a test strip wiper; and

a test strip extending from said plunger toward said liquid receiving end,

said plunger being movable from said liquid receiving end to draw a liquid into said interior bore immersing said test strip therein and thereafter being further moved to wipe said liquid from said test strip using said test strip wiper and position said test strip proximate said test scale.

12. A liquid test device comprising:

a body defining an interior bore, a test scale supported therein, a liquid receiving end and an open end;

a test strip having at least one visually responsive liquid test patch; and

means for drawing a quantity of liquid into said bore through said liquid receiving end and immersing said test patch therein and for wiping said test patch and moving it to proximity with said test scale.