Oxygen generator with two compressor stages

An apparatus for supplying a primary product gas at a relatively high pressure, the apparatus comprising:

• a first compressor means for providing a gaseous mixture at a first relatively low pressure;
• a valving means for alternately channelling the gaseous mixture from the first compressor means alternately to a first end of each of at least two molecular sieve beds for separating the primary product gas from the gaseous mixture;
• a second compressor means which receives the primary product gas from a second end of the molecular sieve beds for maintaining pressure adjacent the second end of the molecular sieve beds at a second relatively low pressure which is less than the first relatively low pressure and for supplying the primary product gas to a primary product outlet at a relatively high pressure which relatively high pressure is greater than both the first and second relatively low pressures;
• and,
• a second compressor start-up valve means for selectively (a) enabling the second compressor to be operated without load for a start-up duration and (b) after the start-up duration, channelling the primary product gas from the sieve beds through the second compressor means to downstream equipment, the start-up valve means being operatively connected with the sieve beds second end and the second compressor means, whereby the second compressor means is able to be started without load.

An apparatus for supplying oxygen rich gas at a relatively high pressure to downstream welding equipment and the like, the apparatus comprising:

• at least two molecular sieve beds for separating an oxygen rich gas from a gaseous mixture, the molecular sieve beds having air inlets at a first end thereof and oxygen outlets at a second end thereof;
• a first compressor means for providing air at a first, positive pressure;
• a valving means for alternately channelling the air from the first compressor means to one of the sieve bed air inlets and for connecting another of the molecular sieve bed air inlets with a waste gas outlet;
• a second compressor means operatively connected with the molecular sieve bed oxygen outlets for drawing the oxygen rich gas to a second, relatively low pressure which is less than the first positive pressure;
• a flow and pressure regulating means operatively between the molecular sieve bed oxygen outlets and the second compressor means for selectively regulating the flow rate and pressure of oxygen rich gas flowing from the molecular sieve bed oxygen outlets such that the second pressure is maintained positive, whereby the flow and pressure regulating means and the second compressor means interact to bring the pressure at the molecular sieve bed second ends to a low but positive second pressure;
• and,
• an oxygen storage tank operatively connected downstream from the second compressor means to receive compressed oxygen rich gas therefrom at a third pressure, which third pressure is greater than both the first and second pressures, the oxygen supply tank being adapted for interconnection with the downstream welding equipment.

An apparatus for supplying an oxygen rich gas at a relatively high pressure to downstream welding equipment, the apparatus comprising:

• a first compressor means for providing air at a first pressure;
• a valving means for alternately channelling the air from the first compressor means alternately to a first end of each of at least two molecular sieve beds for separating oxygen rich gas from the air;
• a second compressor means which receives the oxygen rich gas from a second end of the molecular sieve beds and supplies the oxygen rich gas to a storage tank at a selected, relatively high pressure;
• pressure sensing means for sensing oxygen rich gas pressure in the storage tank;
• and,
• a control operatively connected to the first compressor means, the second compressor means, and the pressure sensing means, the control causing (1) the first compressor means to run substantially continuously and (2) the second compressor means to run intermittently, as necessary to maintain said selected relatively high pressure in the storage tank.