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Publication numberUS3853477 A
Publication typeGrant
Publication dateDec 10, 1974
Filing dateDec 27, 1972
Priority dateDec 27, 1972
Also published asDE2436984A1, DE2436984B2, DE2436984C3
Publication numberUS 3853477 A, US 3853477A, US-A-3853477, US3853477 A, US3853477A
InventorsBlock L, De Wilde R, Spampanato G
Original AssigneeBangor Punta Operations Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Breath analyzer
US 3853477 A
Human breath tester for quantitatively measuring alcoholic content as an indication of the state of intoxication, if any, of any person, typically an automobile driver. The unit is fully transistorized and is programmed to sequence through a purge and blank cycle prior to an actual test to assure a reliable reading. A digital display and printer provide duplicate output readings and a novel sample chamber construction insures accurately metered samples of deep lung breath.
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Description  (OCR text may contain errors)

Unite States atent 1 Block et al.

[ Dec. 10, 1974 BREATH ANALYZER Inventors: Lawrence Allan Block, Point Pleasant; Robert N. De Wilde, Ocean Township; Gavino A. Spampanato, Bricktown, all of NJ.

Assignee: Bangor Punta Operations, Inc.,

Greenwich, Conn.

Filed: Dec. 27, 1972 Appl. No.: 318,788

US. Cl. 23/254 R, 23/255 R, 356/206 Int. Cl. G0ln 21/24, G0ln 33/18 Field of Search 23/232 R, 254 R, 255 R;

References Cited UNITED STATES PATENTS 11/1969 Curry 23/254 R MOUTHPIECE 3,701,601 10/1972 Plumpe, Jr. et al 356/180 X Primary Examiner-Robert M. Reese Attorney, Agent, or Firm-Patrick J. Walsh [57] ABSTRACT Human breath tester for quantitatively measuring alcoholic content as an indication of the state of intoxication, if any, of any person, typically an automobile driver. The unit is fully transistorized and is programmed to sequence through a purge and blank cycle prior to an actual test to assure a reliable reading. A digital display and printer provide duplicate output readings and a novel sample chamber construction insures accurately metered samples of deep lung breath.

29 Claims, 15 Drawing Figures EXHAUST FATIZIITEB 3.853.477



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PATENIEB DEC 1 01974 SHEEI near 14 FIG. 7B

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BREATH ANALYZER This invention relates to a device for testing human breath and more particularly to a full programmed instrument for quantitatively measuring the alcoholic content of the aveolar or deep lung breath of a human being as an indication of the amount of alcohol in the blood. The tester of this invention is particularly adapted for use in indicating the state of intoxication, if any, of the operator of an automotive vehicle.

The role of the intoxicated automobile driver in traffic crashes has become a matter of international concern. Within the United States the Federal administration as well as most state and local law enforcement agencies have assigned a high priority to the relationship between alcohol and the traffic safety problem.

One aspect of the drinking driver problem involves a determination of the drivers level of intoxication. The field of chemical testing for intoxication has shown a solid and continual progress. This progress has been in part the result of many highly qualified representatives of the enforcement, scientific and judicial disciplines devoting their talents and time to provide the exhaustive and methodical guidance to the field that has brought about success. Their contributive influences are perhaps most readily evidenced in the increasingly stringent performance standards being recommended for quantitative breath alcohol instrumentation.

In U.S. Pat. No. 2,824,789 issued Feb. 25, I958 there is disclosed an instrument for testing the alcoholic content of the human breath based upon the change in the transmission of light by a chemical solution through which the breath has been passed. In the device of that patent a light source is movably positioned between a pair of ampoules containing a solution of potassium dichromate in sulfuric acid. In accordance with the amount of alcohol or the like in a charge of gas passing through the solution it becomes more transparent. By moving the light source in such a direction as to equalize the amount of light passing through a test ampoule and a reference ampoule filled with the same solution, the position of the light source is indicative of the alcoholic content in the charge of human breath which has been passed through the test ampoule. This is an indication of the alcoholic content in the human blood stream and consequently an indication of the state of intoxication of the person whose breath has been sampled. A somewhat similar cam operated device is disclosed in U.S. Pat. No. 3,552,930.

The present invention is directed to a quantitative breath alcohol measuring instrument of the same general type but of improved construction and in particular to an instrument in which the test sequence is almost completely electronically controlled. Computerized operational programming in the device of this invention in combination with solid-state electronic circuitry results in a virtually fail-safe" operational reliability. The instrument is under the control of a selfcontained program counter which acts as the instrument brain. After the unit has undergone complete purging an indicator lights and the human breath sample is introduced. The program counter then electronically monitors each subsequent phase of the test. The unit is insensitive to line voltage variation or temperature insuring an accurate test result under all operating conditions.

In the present invention the person whose breath is to be sampled blows into a mouthpiece connected to the instrument. After a certain portion of the breath has been wasted or exhausted to atmosphere the remaining portion or so-called deep lung portion is captured in a sample chamber. When the chamber is filled, a switch is closed and the breath sample in the chamber flows through or bubbles through the solution in the test ampoule. Any change in the transmission of light through the test ampoule with reference to a second standard ampoule of the same solution is sensed by a servo system which produces a digital or pulse output indicative of the change in the light transmission. These output pulses are used to activate both a digital light display and a printer so that a permanent record of the test reading is created.

However, before the test cycle described above, the instrument is programmed to go through two preceding cycles hereafter referred to as a purge cycle and a blank cycle. During the purge cycle air is pumped through the sample chamber to make sure that no residue from previous samples remain. After the system has been completely purged a first run or blank" run is made with a sample of captured air to insure that all readings are correct and all portions of the system are operating properly. Only after the purge and blank cycles have been completed is an actual test made.

Thus, there are three major divisions to the program cycle. The first division hereinafter referred to as purge is that in which air is pumped through the breath chamber to drive out traces of alcohol and moisture from any previous test. The second division or cycle is the blank cycle in which a reading is taken to assure that the breath chamber is not contaminated. The third or last cycle is that in which an actual breath sample is tested.

Each of these three major divisions or cycles is further subdivided into four minor divisions or steps. In the first step called pump, in the purge or blank cycle (or blow step in the sample cycle) the breath chamber is pushed up by the pump (or by the person blowing into the mouthpiece). In the second step called bubble the piston is allowed to drop, bubbling the contents of the breath chamber through the test ampoule. In the third subcycle or third step called analyze the change in light transmission through the ampoule is detected and in the fourth step called read, the results of the tests are displayed on the read out lights and printed on a suitable ticket to form a permanent record.

It is, therefore, one object of the present invention to provide an improved method and apparatus for quantitatively measuring the amount of alcohol or similar material in a gas sample.

Another object of the present invention is to provide an improved quantitative breath alcohol instrument.

Another object of the present invention is to provide an improved breath tester having increased reliability of operation to insure a more accurate result.

Another object of the present invention is to provide a breath testing instrument in which the instrument is purged by air after each test sample.

Another object of the present invention is to provide an improved method and apparatus for testing breath samples in which each test involves three cycles, namely, a purge cycle in which the system is purged by air, a blank cycle in which a reading is taken against an air sample and finally a third or test cycle in which an actual breath sample is tested.

Another object of the present invention is to provide a fully transistorized quantitative breath alcohol instrument of simplified, improved construction and one that is readily portable.

Another object of the present invention is to provide an alcoholic content breath tester including both an optical or visual readout and a printed or permanent record readout.

Another object of the present invention is to provide a breath tester inwhich the result of the test is displayed in digital form.

Another object of the present invention is to provide a human breath tester in which the sequence of events undergone during a test are programmed by a control circuit in the tester.

These and further objects and advantages of the invention will be more apparent on reference to the following specification, claims and appended drawings wherein:

FIG. 1 is a perspective view of a quantitative breath alcohol instrument constructed in accordance with the present invention.

FIG. 2 is a simplified operational diagram of the tester of FIG. 1.

FIG. 3 is a simplified block diagram for the tester of FIG. 1.

FIGS. 4A and 4B taken together show an overall wiring diagram with parts in block form for the tester of FIG. 1.

FIG. 5 is a timing diagram for the tester showing the purge, blank and sample cycles.

FIG. 6 is a view of the component side of the control board for the tester of FIG. 1 and FIGS. 7A through 7F taken together constitute a detailed circuit diagram of the logic for the tester of FIG. 1.

Referring to the drawings, FIG. 1 shows the breath tester of the present invention generally indicated at 10 as comprising a housing 12 from which projects a tube and associated mouthpiece 14, into which the person whose breath is to be sampled blows. Also mounted on housing 12 is a nameplate 16 and a plurality of indicator lights 18. A reading from a test sample is adapted to be displayed by a visual indicator 20 preferably comprising a three digit display in which each digit is formed by a seven bar segment array of lights. At the same time as a reading is shown on indicator 20 a permanent record of the test results is printed on a card 22 adapted to be inserted into a slot 24 in housing 12. FIG. 1 also shows a reference or standard ampoule 26 received in a suitable receptacle in the tester and also shows a test ampoule 28 into the top of which projects the end of a bubble tube 30. Tester 10 is shown as received in the lower half of a case 32 by means of which it may be carried from place to place and is adapted to be plugged into a conventional 60 Hz 1 17 volt a.c. electrical outlet. Electrical energy supplied to the tester 10 is under the control of a three position switch 34 adapted to be manually moved between off, reset and run positions.

FIG. 2 is a simplified operational diagram of the tester 10 of FIG. 1. In FIG. 2 the mouthpiece l4 communicates with a tube 36 in which is located a solenoid valve 38 adapted to be opened by what will hereinafter be referred to as the blow solenoid. The breath sample after passing through valve 38 goes through a tube 40 and an entrance tube 42 to the interior of a sample chamber or breath chamber indicated at 44. Movable through breath chamber 44 is a piston 46. In its lowermost position within chamber 44 piston 46 is adapted to engage and actuage a bottom switch 48 for a purpose more fully set forth below.

When the person whose breath is to be sampled blows into the mouthpiece 14 the breath passes through solenoid valve 38 into chamber 44 driving piston 46 upwardly to its uppermost position as illustrated. The breath continues to overflow through tube" 92 into cylinder 96 moving piston 98 upward until top switch 100 is made. When breath flow stops, contact breaks at top switch 100. Valve 38 is closed and a second solenoid valve 50 is opened by what is hereinafter referred to as the Bubble solenoid. Valve 50 communicates with an exit tube 52 from sample chamber 44 and permits the breath sample to flow from chamber 44 by way of exit tube 52 and valve 50 to a bubbler tube 54, the lower end of which is received in the test ampoule 28. This ampoule is partially filled with a liquid as indicated at 56 in FIG. 2 so that the breath sample exiting from the lower end of bubbler tube 54 passes in the form of bubbles through the solution 56. After the breath sample has been bubbled through solution 56 and after a waiting period 90 i 30 seconds for chemical reaction is completed, the yellow color of the solution changes to a lighter shade of yellow, thereby permitting increased light transmission through the solution. The increased light transmission through solution 56 is compared with the light transmission through an identical reference solution 58 in the standard ampoule 26. For this purpose, a lamp 60 is mounted on a carriage 62 positioned between the standard ampoule 26 and the test ampoule 28 and is movable back and forth between the ampoules as indicated by the arrows 64 with the rotation of a screw 66 thread engaging carriage 62. Screw 66 is rotated by a servomotor 68 under the control of a servo-amplifier 70. Servo-amplifier 70 has its input connected to the output of a pair of photocells 72 and 74 with photocell 72 positioned to intercept light from lamp 60 passing through the solution 58 in ampoule 26 and photocell 74 positioned to intercept light transmitted from the lamp through the solution 56 in test ampoule 28. In order to render the photocells sensitive primarily to blue light (440 millimicrons), the blue filters 76 and 78 are positioned between the respective ampoules and their corresponding photocells. Screw 66 is connected by driver wheel 80 and driver wheel 82 to an output shaft 84 whose angular position is indicative of the displacement of lamp 60. The amount of rotation of output shaft 84 is sensed by a photoelectric pickup 86 and the output of the pickup is supplied over leads 88 and 90 to the three-digit optical display 20.

The interior of breath chamber 44 is connected by a tube 92 and valve 94 to the interior of a second chamber or waste chamber 96. Movable through chamber 96 is a second piston 98 and in its uppermost position this piston is adapted to engage and actuate a top switch 100. In the preferred embodiment, valve 94 is a proportioning valve such that approximately oneeighth of the overflow from chamber 44 passes into chamber 96 and the other seven-eighths of the gas charge overflow from chamber 44 is exhausted to atmosphere through exhaust tube 102. The object of the second chamber and proportioning valve is to ensure a sample of more than 400 ml. being expired by the subject being tested. This ensures a sample of alveolar or deep lung breath to be analyzed.

An alternative method (not shown) for measuring 400 ml. is to use a second chamber 96 with a volume of 400 ml. All exhaust from the first chamber 44 would pass into chamber 96 and be further exhausted from there.

A second alternative method (not shown) for measuring 400 ml. is measure the time during which ex haust is flowing from the first chamber 44. A given flow rate for a given period of time is equal to a given volume.

Breath chamber 44 is adapted to be purged by air from a pump 101 connected to a second inlet tube 104. This air passes through a solenoid valve 106 actuated by what is hereinafter referred to as a pump solenoid, through a tube 108 and common tube 42 to the interior of chamber 44. The pump not only supplies air during the purging cycle but also supplies air to sample chamber 44 during the blank cycle when a measurement is taken against a charge of pure air as more fully described below at pages 22 and seq.

FIG. 3 is a simplified block diagram for the tester of FIG. 1 in which like parts bear like reference numerals. The piston switches 48 and 100 along with run switch 34 actuage a program counter 103 under the control ofa system clock 105 which by way of example only may be driven at the line frequency of 60 Hz. Program counter 103 and clock 105 form part of a control board indicated by the dash line 107. Program counter 103 also receives an input from a heat responsive bimetallic thermostat 110 which prevents operation of the device until the proper operating temperature has been reached. An alternative device to the thermostat is an electronic thermistor circuit capable of determining the proper operating temperature. Also mounted on the control board, connected to program counter 103 and supplying outputs to a plurality of drivers 112 is a program decoder 114. Drivers 112 actuate a pump solenoid 116 which actuate the pump valve 106 of FIG. 2, a blow solenoid 118 which actuates a blow valve 38 of FIG. 2 and a bubble solenoid 120 which actuates bubble valve 50 of FIG. 2. Also actuated by drivers 112 is the lamp 60 and the windings 122 of servo-motor 68. Photometer pickup 86 is connected to a pickup counter 124. The pickup counter 124 counts the pulses from the photometer pickup 86 indicative of the position of lamp 60 and supplies the count through a counter decoder driver 126 to the digital display and to a printer 128.

FIGS. 4A and 4B taken together show an overall wiring diagram for the tester 10. Again, like parts bear like reference numerals in FIGS. 4A and 4B. A pair of power supply leads 130 and 132 connected to a conventional a.c. outlet are adapted to supply I 17 volt 60 Hz a.c. electrical energy to the unit through the three position switch 34 having the ganged movable contacts 134 and 134' movable in unison between the uppermost or off position, the intermediate reset position and the lowermost run position in FIG. 4A. 12 volt electrical energy is fed from the supply line through a stepdown transformer 136 to the driver card 112 and 24 volt electrical energy is supplied to the servo-amplifier 70 by way of a stepdown transformer 138. Full line voltage is applied by way of leads 140 and 142 to the printer 128. Electrical energy is supplied to control card 107 through a transformer 144 having a center tapped secondary 146. Also connected to control card 107 is the thermostat 110, the breath chamber bottom switch 48, the top switch and cover interlock switch 111. An additional feature illustrated in FIG. 4B is the photo-pickup 86 which is shown as comprising a pair of lamps 148 and 150 adapted to transmit radiant light energy to a pair of photosensors in the form of phototransistors 152 and 154. The light sources 148 and 150 and sensors 152 and 154 straddle a disc which is provided with a concentric circle of small holes (not shown). This disc is part of the photopickup 86. As light is periodically passed through the holes with rotation of the disc each hole allows the light source to reach its corresponding phototransistor, thus creating pulses to the counter 124 of FIG. 3. In the preferred embodiment when the servo-motor drives the lead screw 66 (FIG. 2) and driver wheel 80 and in turn the driver calibration wheel 82 on shaft 84, it rotates the above described disc of the photopickup 86.

FIG. 5 is a timing diagram for the tester 10 of FIG. 1. The timing diagram of FIG. 5 is divided by the vertically dashed lines 156 and 158 into three cyles or three time periods labeled purge, blank and sample, respectively. Waveform 160 in FIG. 5 illustrates the run position of switch 34 during all three cycles. Waveform 162 illustrates the energization time of the pump solenoid 116, waveform 164 illustrates the operation of the bubble solenoid 120 and waveform 166 indicates the time of operation of the blow solenoid 118. Waveform 166 is broken away at 168 to indicate the variable nature of the time for the blow cycle which depends on how fast the sample chamber is filled by the person blowing into the mouthpiece. The operation of the piston bottom switch 48 is illustrated by the waveform 170 in FIG. 5 and the operation of the top switch 100 by the waveform 172. Energization of lamp 60 is illustrated by waveform 174, actuation of the servomotor by waveform 176 and the printer is actuated during the blank sample cycle as indicated by the waveform 178.

Following is a step-by-step description of a typical operating procedure for the tester 10 of FIG. 1. The person whose breath is to be sampled should be kept under strict observation for a minimum of IS minutes during which time nothing should be ingested by mouth and no smoking permitted.

STEP l Unlock the instrument cover latch and remove the top cover. Attach the power cord in the receptacle in the back of the instrument and insert the plug into any l 10 volt a.c. power outlet.

STEP 2 Advance the function switch 34 located in the lower lefthand corner of the top panel from the off position to the reset position. STEP 3 Upon concluding step 2, the operator of the tester will notice the wait program indicator is illuminated. This indicator is only illuminated when the instrument is not maintained at the required operational temperature of 50C. with tolerance of i3. When this indicator is illuminated the instrument does not allow the program counter to initiate any test activity. When the temperature is within the tolerance, the wait indicator goes out and the operator may continue with the test procedure.

STEP 4 Gauge both the reference and test ampoules and insert them into the tester. This includes opening the test ampoule and the connection of the bubbler tube 54 into the specimen delivery outlet of the test ampoule. This step may be completed along with following step while the operator is waiting for the instrument to attain operating temperature.

STEP 5 Insert the result ticket into the printer by way of the small slot 24 in the left-hand side of the front panel. The printed format end of the ticket is inserted first, pushing the ticket into the printer until the printer mechanism grabs the ticket and does not permit further insertion.

STEP 6 As soon as the wait indicator goes out, advance the function switch 34 from the reset position to the run position. At this time the tester becomes virtually selfcontained and operates to the conclusion of the test sequence. The operator of the instrument for the most part simply monitors the program functions but provides some external guidance of a nature which is not an integral increment of the operational loop of the instrument.

STEP 7 Step 6 will cause the purge" program indicator to illuminate and at the same time creates a .88 reading on the display 20. This display confirms that all elements of the Numitron tubes used for the display are functioning. The various operations of the instruments purge phase are sequentially executed. The conclusion of the purge is indicated by the sound of the printer 128 operating almost immediately and by the illumination of the read" program indicator. At this stage the display tubes still read .88 as its lamp test, the results ticket 22 has printed on it the same .88 reading in the purge location on the ticket confirming that the tube displays mechanisms are interlocked, and the purge and read program indicators will be illuminated. In approximately five seconds the program counter 103 of FIG. 3 commands a reset of all displays and the activation of the next phase.

STEP 8 The program counter proceeds to command the instrument to perform a blank test on ambient air. During this phase the blank indicator is illuminated. Again at the conclusion of this phase, the printer can be heard printing the results of the analysis in the blank location on the results ticket 22, and the illumination of both the blank and read program indicators for a duration of approximately five seconds before the program counter advances to the next phase. The operator must monitor the performance of the instrument at this stage. After the instrument has completed a blank analysis on ambient air, the operator must inspect the analysis result printed on the ticket to confirm that the blank analysis result does not exceed 0.0lpercent. A reading of 0.01percent is considered an excessive blank and the operator should not proceed to the next step but rather return to step 5 and proceed again.

STEP 9 When the blank analysis has been successfully completed, the operator instructs the person whose breath is to be sampled to follow the illuminated instructions displayed by the program indicator, namely, sample" and blow." This person simply blows into the instrument through the mouthpiece 14 located in the upper right-hand corner of the top panel in FIG. 1 until the blow program indicator light goes out. STEP 10 The program counter 103 continues to command the instrument through the remainder of the test of the breath sample. At the conclusion of the test the printer can be heard operating and the illumination of the read program indicator light is added to the sample indicator. This concludes the test and in this phase both the read and sample indicator lights remain on.

STEP 1 1 After removing and disposing of the test ampoule, bubbler tube 4 and the results ticket 22, the instrument should be secured for storage or if subsequent testing is desired the function switch 34 is returned to the reset position.

ALTERNATE TEST SEQUENCE For a demonstration of the instruments ability to properly analyze a reference standard of a predetermined simulated breath alcohol concentration, a single change in the sequence is required. Steps 1 through 8 remain the same but step 9 is modified as follows. STEP 9A When the blank test has been successfully completed, the operator attaches the breath delivery tube attached to mouthpiece 14 to a suitable simulator and blows the vapor of the simulator into the instrument until the blow program indicator light goes out. After this, all subsequent steps remain the same as given above.

The tester 10 is a completely computerized and transistorized device utilizing transistortransistor logic to control the operating functions of the instrument. Program counter 103 of FIG. 3 is the brain of the instrument and this circuit performs the twelve basic functions or steps in proper chronology. The program counter is affected basicaly by four outside signals which are generated by the function switch 34, the temperature interlock, the piston switches 48 and of FIG. 2 and the program clock 105 of FIG. 3. The function switch 34 both initiates the warmup and activation of the program cycle. The instrument is warmed up by a conventional heater (not shown) and the temperature is sensed by the thermostat of FIG. 3. This thermostat or temperature interlock prevents any program activity when the instrument is not within the temperature tolerances. The piston swithces provide signals indicating the full and empty positions and the program clock provides electronic timing as required by the program.

The program decoder 114 of FIG. 3 monitors the position of the program counter 103. Depending upon the program phase the decoder 114 actuates the components under its control, namely, the pump solenoid 116, blow solenoid 118, bubble solenoid 120, a lamp 60 and the servo-motor. Depending upon the step of the program counter, the program decoder signals the drivers 112 of the various components to accomplish the required function. The servo-motor 68 of FIG. 2 is connected to the lead screw 66 and is supplied with current to drive the light carriage 62 in the appropriate direction to achieve a null. The servo-amplifier 70 is a solid-state printed circuit board which monitors the signals generated by the photocells 72 and 74. It detects the imbalance in cell output and commands motor 68 to drive the light carriage to a null. When the null condition is reached, no power is supplied to the servomotor 68 and the null is maintained.

Program decoder 114 in FIG. 3 also energizes the pick-up counter 124 which drives the counter decoder driver and the outputs and 128. This activation occurs during the measurement of a blank or sample sequence and at this time the program decoder 114 enables the pickup counter 124 to actuate the readouts. Counter 124 receives and digests the pulses from the pickup 86 and forwards display information to the counter decoder driver 126 which in turn produces the required signals to present the appropriate results on the display tubes and on the printer ticket.

Referring to FIG. 2, piston 46 in sample chamber 44 is normally located at the bottom of the chamber resting against bottom switch 48. When a charge of gas is appled to the chamber, piston 46 is driven upwardly uncovering outlet 92 and overflow from this chamber passes through proportioning valve 94 into chamber 96 also driving the piston 98 upwardly. In its uppermost position, piston 98 actuates switch 100 indicating a full charge. Solenoid valve 38 then closes and bubbler valve 50 opens. The weight of the pistons cause them to move downwardly with the gas in chamber 96 wasting through valve 94 and exhaust tube 102 to atmosphere while the gas charge in chamber 44 is driven by piston 46 through valve 50 and bubbler tube 54 into test ampoule 28. When piston 46 reaches its bottommost position, switch 48 is activated to indicate that a full charge has been bubbled through the test ampoule. By incorporating the separate waste chamber 96 the person whose breath is being sampled is required to expire a volume of breath in excess of 400 ml before the sample is deemed acceptable. Even though the minimum quantity has been expired the person can continue to blow the advance to the next phase is activated any time after the minimum expiration when the person stops blowing. The volume measurement of the breath sample is approximate 55 to 58 ml at operational temperature. As previously indicated, the reagent in the ampoules is of a standard size and preferably a solution of potassium dichromate in a sulfuric acid solution such that the dichromate of the solution oxidizes the ethyl alcohol in the breath sample. The program indicators generally shown at 18 in FIG. 1 are six in number as more fully described below.

FIG. 6 is a view of the component side of the control card 107 of FIGS. 4A and 4B. This board is mounted on the top left side of the instrument and controls the operating and timing sequence of the unit. The board also provides the digital display of the blood alcohol determined from the breath sample test and drives the digital printer to provide a permanent record of the reading obtained. The six lamps on the board indicate the operating status of the tester. FIGS. 7A through 7F show a detailed circuit diagram of the logic elements mounted on the board 107. Like parts in FIGS. 7A through 7F bear like reference numerals.

Referring to FIGS. 6 and 7A through 7F, the control board 107 uses nine numbers of the standard 7400 series TTL family in molded plastic packages. The SN7400N, SN7404N, SN74l0N, SN742ON, and SN7453N are general purpose logic gates. The CDZSOOE (or SN7446AN) is a special purpose logic block which decodes a number in binary coded decimal form to the seven lines required to drive a seven segment display tube and the SN7493N, SN74103N and DM8280 (SN74175N) perform counting and storage functions. The designation given a particular package in these drawings is determined by its position on the board with respect to a grid specified in FIG. 6 by numbers 1 through 8 as indicated at across the top of the board and letters A, B, IC, D and E down the side of the board as indicated at 182. Thus, D3 for example is the package in FIG. 6 (and FIGS. 7A through 7F) at the intersection of row D and column 3. Viewing the package from the top the pins are numbered in a clockwise direction from the end marked with a notch or a dot.

The power supply is generally indicated at 184 in FIG. 7A and is nominally a 5.0 volt i Spercent. The zero (low) logic level is typically 0.2 volt and the one" (high) is typically 3.5 volt.

As previously indicated, there are three major divisions to the program cycle of the tester, namely, purge in which air is pumped through the breath chamber to drive out traces of alcohol and moisture from any previous test; blank in which a reading is taken to assure that the breath chamber is not contaminated, and sample in which the actual breath sample is tested. Each of these can be subdivided into four minor steps. In the first minor step or subcycle called pump, in the purge or blank cycle (or blow in the sample cycle) the breath chamber piston is pushed up by the pump (or by the person blowing). In the second subcycle called bubble, the piston is allowed to drop, bubbling the contents of the chamber through the test ampoule. In the third subcycle called analyze, the change in the ampoule is detected and in the fourth subcycle called read, the results of the test are displayed on the readout and printed on the ticket.

The program counter 103 with the four flip-flops labelled B-l in FIG. 7F has a unique set of outputs for each of the twelve steps in the program. This relationship is shown in the following table.

Read 0 l

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U.S. Classification422/85, 356/435, 422/91, 356/437
International ClassificationG01N33/483, G01N33/497
Cooperative ClassificationG01N33/4972
European ClassificationG01N33/497A