Patent ID: 7699053

Claim:
A powered air-purifying respirator system comprising: a battery pack having a battery and a current control means; and a respirator unit having a blower, said blower having an impeller for pulling air through a filter and pushing the filtered air to a headpiece, and a motor in electrical communication with said battery for driving said impeller; a current sensor for sensing the current flow and providing corresponding sensor output; a current control logic means for receiving said sensor output and generating a control signal when said current flow has exceeded the threshold value for said predetermined amount of time; a current control switch means for stopping said current flow in response to receiving said control signal from said current control logic means; and a means for resetting the current control logic means in response to connection of said battery to a battery recharger unit; wherein said current control means is for sensing a current flow from the battery to the motor and stopping the current flow when the current flow exceeds a threshold value for a predetermined amount of time; wherein said current control logic means further provides for latching the control signal following a trip event such that said current control switch means stops the current flow until the current control logic means is reset; wherein said current control logic means has an enable input which must be toggled to reset the current control logic means following the trip event; wherein said battery pack further has a positive battery pack terminal in electrical communication with a positive terminal of said battery, and a negative battery pack terminal in electrical communication with a negative terminal of said battery; and wherein said means for resetting is a one-shot circuit having a trigger input and a pulse output, said trigger input connected to said positive battery pack terminal, said pulse output connected to said current control logic means enable input, said one-shot circuit generating a pulse on said pulse output in response to connecting said positive battery pack terminal and said negative battery pack terminal to said battery recharger unit.