Patent ID: 7895878

Claim:
A breath test simulator for producing breath test vapor having a known concentration of ethyl alcohol, the simulator comprising a container adapted to receive a water/ethyl alcohol solution having a known concentration of ethyl alcohol; a top housing comprising a thermally conductive body forming a metal lid closing the top of the container and a metal passage portion on the lid and extending to one side of the lid; a first heater in the container, a first temperature sensor in the container, a temperature control circuit responsive to the first sensor for actuating the first heater to heat solution in the container to a temperature in a first operating range, a second temperature sensor in the container, a temperature monitoring circuit responsive to the second sensor for actuating a temperature display when the solution is in a second operating range greater than and extending to either side of the first operating range and for generating an error signal and shutting down the simulator when the solution temperature is outside the second operating range, said second operating range within a regulatory allowable operating range so that the error signal is generated and shut down occurs when the temperature of the solution is in the regulatory allowable operating range; a second heater on the body; an inlet passage for flowing air into the container, the inlet passage extending from an inlet port on the outside of the simulator, through the passage portion and into the container; and an outlet passage, the outlet passage extending from the interior of the container, through the passage portion and to an outlet port on the outside of the simulator; the passage portion comprising a metal thermal mass surrounding the inlet passage and extending along the inlet passage a distance greater than the thickness of the lid, the thermal mass in heat flow communication with the second heater; wherein the metal thermal mass is heated by the second heater and retains heat to warm air flowed through the inlet passage when the second heater is not actuated.