CONTROL SYSTEM FOR QUIESCENT BREATH TESTER

• US 3,858,434 A
• Filed: 12/11/1972
• Issued: 01/07/1975
• Est. Priority Date: 12/11/1972
• Status: Expired due to Term

• Current Assignee: Alcohol Countermeasure Systems Corp.
• Original Assignee: Donald H. Ward, Joseph P. Hoppesch, Kenneth W. Padgitt
• Inventors: Hoppesch, Joseph P., Ward, Donald H., Padgitt, Kenneth W.
• Primary Examiner(s): Queisser, Richard C.
• Assistant Examiner(s): Kreitman, Stephen A.
• Application Number:
  US05/313,891
• Time in Patent Office: 757 Days
• Field of Search: 73/23,27R,421.5R 23/232R,254R,255E,254E 128/2.08 340/213Q,252H,420 219/506
• US Class Current: 73/23.3
• CPC Class Codes: G01N 33/4972 Determining alcohol content for vehicle safety devices B60K28/06

Abstract

A control system for a breath tester is disclosed. The tester includes a chamber in which a breath sample is stored, a detector unit positioned to test breath therein and means for shielding the detector unit from the chamber while breath is flowing into the chamber and for unshielding the detector unit thereafter to provide a relatively quiescent breath sample to the detector. A purge pump is also provided. The control system includes means for sensing the breath flow into the chamber during the test and for automatically cutting off that flow, timing a period to allow a quiescent state to be reached and only then allowing the detector unit to be unshielded. It also employs the initial offcycling of a thermostatically controlled heater, after the turning-on of the tester, to indicate the approach of operating conditions and includes interlocks to prevent improper operation and to ensure consistent results.

Claims

1. In a breath tester of the type having a breath holding chamber, an alcohol detecting element for producing a signal in response to the alcohol in its gaseous environment, means for selectively shielding and unshielding the element from the chamber, and purge means for at least, purging the gaseous environment about the detecting element;

a control system comprising;

first means for sensing and signaling the shielded and unshielded state of the shielding means; and

second means responsive to the said first means for operating said purge means for a preset period in response to the change of the state of the shielding means from unshielded to shielded.

2. The invention of claim 1, wherein said second means includes means for producing a ready signal after the purge means has operated for the preset period.

3. The invention of claim 2, wherein the ready signal occurs after a further settling period after the preset period is over.

4. In a breath tester of the type including a cell adapted to receive a gas sample to be tested, an alcohol responsive detecting element, means for shielding and unshielding the element, a test indicator and output indicating means for giving an indication of the tested alcohol level, the improvement comprising:

means for signaling the delivery of a breath sample to the cell;

timing means, responsive to said above-mentioned means signaling of the delivery of a sample, for timing out a pre-set quiescent period and for generating a command after that period;

means for controlling said shielding means so that it may unshield the element at the end of the quiescent period;

means for signaling the unshielding of the cell;

additional timing means, responsive to said means for signaling the unshielding of the cell, for producing a read signal after a predetermined period; and

a read indicator responsive to the read signal for indicating that the output indicating means is to be read.

5. The invention of claim 4 wherein the tester includes purge means, including inlet means connected to admit purging gas for purging at least said shielded element, and said purge means is activated by the re-shielding of the element to purge the element by propelling the purging gas across it.

6. In a fluid tester of the type including a cell adapted to receive a fluid sample to be tested, a suitable chemical detecting element and means for shielding and unshielding the element, the improvement comprising:

means for signaling the delivery of a suitable sample to the cell; and

means for controlling said shielding means coupled to said signaling means, so as to unshield the element only in response to a signal from said signaling means indicative of the delivery of a suitable sample to the cell.