US 5,368,019 AGranted

System and method for operating a respirator compressor system under low voltage conditions

AssigneePuritan-Bennett Corporation

InventorGary Latorraca

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Abstract

The system and method for operating an AC respirator compressor system at substantially subnormal line voltages includes a compressor, an accumulator, a solenoid unload or dump valve used to reduce the pressure at the outlet of the compressor, a check valve located downstream from the solenoid, a relief valve, a pressure sensor, and an AC voltage sensor. In a preferred embodiment, the compressor constantly supplies compressed air to the ventilator system, monitoring the accumulator pressure and activating the solenoid unload valve as required to maintain an acceptable range of pressure in the accumulator. In another preferred embodiment the compressor system can also be operated in an intermittent, or standby mode, to supply compressed air as needed. The respirator compressor system can maintain an acceptable range of pressure in the accumulator even during periods of low AC line voltage by monitoring both the accumulator pressure and the AC line supplying voltage to the respirator compressor system, and modulating the action of the solenoid unload valve to achieve low AC voltage operation.

Claims6

Dependent claims

A method for operating a respirator compressor system at low voltage, said respirator compressor system including a rigid accumulator for temporarily storing gas within a desired pressure range for supplying the gas to a ventilator system, a gas compressor driven by an electric motor, said gas compressor having an inlet for gas to be compressed and an outlet for compressed gas in fluid communication with said accumulator, a solenoid unload valve connected in fluid communication with said outlet of said gas compressor for reducing the pressure at the outlet of the compressor, a pressure sensor for measuring gas pressure within said accumulator operative to generate an electrical signal indicating accumulator pressure, an AC voltage sensor for measuring voltage supplied to said electric drive motor of said gas compressor, and control logic means for controlling operation of said solenoid unload valve, comprising the steps of:

operating said gas compressor to charge said accumulator with pressurized gas;
measuring the gas pressure in the accumulator and generating an electrical gas pressure signal representing accumulator gas pressure;
measuring line voltage to the drive motor of the gas compressor, and generating an electrical line voltage signal representing said voltage;
providing a command signal to modulate the operation of the solenoid unload valve to lower the output pressure of the compressor responsive to said gas pressure signal and said line voltage signal, thus preventing compressor stall over a broader input voltage range than would otherwise be possible.

1 more element

Dependencies are inferred from the claim text.