Method and apparatus for maintaining airflow in a powered air purifying respirator in high magnetic fields
Assignee3M Innovative Properties Company
InventorsKenneth J. Krepel, Douglas D. Jensen, James F. Poch, Dale M. Bissen, Michael L. Parham
Life of this patent
Estimating the term…
Abstract
A blower/filtration unit for a powered air purifying respirator (PAPR) is presented that includes a motor configured to operate in a standard mode and in a high magnetic field (HMF) mode. The unit also includes a magnetic field sensor. The unit also includes a controller comprising a control mode switching function. The controller executes the control function upon detection of a magnetic field strength that exceeds a reference threshold magnetic field strength. The control function switches the motor operation from the standard mode to the HMF mode.
Claims19
1-37. (canceled)
A system for maintaining airflow in a powered air-purifying respirator (PAPR) comprising:
- a magnetic field strength sensor that detects a magnetic field strength in an environment;
- and
- a PAPR comprising:
- a magnetic field strength receiver;
- a motor;
- and
- a controller that provides a motor speed algorithm to control a motor speed of the motor upon detection of an environmental magnetic field strength that exceeds a reference threshold magnetic field strength.
A blower/filtration unit for a powered air purifying respirator (PAPR) comprising:
- a motor configured to operate in a standard mode and in a high magnetic field (HMF) mode;
- a magnetic field sensor;
- and
- a controller comprising a control mode switching function, wherein the controller executes the control function upon detection of a magnetic field strength that exceeds a reference threshold magnetic field strength, and wherein the control function switches the motor operation from the standard mode to the HMF mode.
A method of maintaining airflow in a powered air-purifying respirator (PAPR) comprising:
- providing a PAPR comprising a motor, a magnetic field sensor, and a controller, the controller comprising a high magnetic field (HMF) flow function and a calibrated flow function;
- storing a reference threshold magnetic field strength in the controller;
- reading a motor speed necessary to generate a compliant air flow in an ambient magnetic field environment and storing the motor speed as a reference motor speed;
- periodically reading magnetic field strength and comparing the reading to the reference threshold magnetic field strength;
- wherein the HMF flow function is executed in response to the magnetic field strength reading that exceeds the reference threshold magnetic field strength and the calibrated flow function is executed in response to a magnetic field strength reading that falls below the reference threshold magnetic field strength.
Dependencies are inferred from the claim text.