Self-contained oxygen generator

• US 7,195,028 B2
• Filed: 08/02/2004
• Issued: 03/27/2007
• Est. Priority Date: 08/04/2003
• Status: Active Grant

• Current Assignee: L'Air Liquide SA
• Original Assignee: L'Air Liquide SA
• Inventors: Schmutz, Nicolas, Jean, Philippe, Basset, Chrystelle
• Primary Examiner(s): Krishnamurthy; Ramesh
• Application Number:
  US10/909,625
• Publication Number:
  US 20050028868A1
• Time in Patent Office: 967 Days
• Field of Search: 137/115.03, 137/114, 137/486, 137/487.5, 128/204.21, 128/204.22
• US Class Current: 137/115.03
• CPC Class Codes: B01D 2253/108 Zeolites
• CPC Class Codes: B01D 2256/12 Oxygen
• CPC Class Codes: B01D 2257/102 Nitrogen
• CPC Class Codes: B01D 2259/40003 Methods relating to valve switching
• CPC Class Codes: B01D 2259/402 using two beds
• CPC Class Codes: B01D 2259/4533 for medical purposes
• CPC Class Codes: B01D 2259/4541 for portable use, e.g. gas masks
• CPC Class Codes: B01D 53/053 with storage or buffer vessel
• CPC Class Codes: Y10T 137/2572 One inflow supplements another
• CPC Class Codes: Y10T 137/2579 Flow rate responsive
• CPC Class Codes: Y10T 137/7761 Electrically actuated valve

Abstract

A self-contained oxygen generator containing a PSA unit and a flowmeter in the outlet line. The flowmeter provides a signal which represents the flow rate of the oxygen in the outlet line. A leakage circuit with a calibrated orifice and a solenoid valve are also located on the outlet line. In response to a signal from the flowmeter, the solenoid can be actuated so as to provide a calibrated leakage at the outlet of the PSA. This calibrated leakage is useful when overall oxygen usage is too low.

Claims

1. An apparatus which may be used as a self-contained oxygen generator comprising:

a) a generator inlet;

b) a PSA unit, wherein said unit comprises at least one adsorber;

c) an oxygen outlet line;

d) a flowmeter, wherein said flowmeter;

1) is located in said outlet line; and

2) provides an electrical flow rate signal representative of the flow rate of oxygen passing through said outlet line;

e) an outlet line leakage circuit comprising;

1) a solenoid valve that can be actuated in response to said signal; and

2) a calibrated restriction; and

f) an electronics element electrically connected to said flowmeter and said solenoid valve, wherein said electronics element, said flowmeter and said solenoid valve are configured such that;

1) said electronics element receives said electrical flow rate signal from said flowmeter

2) said solenoid valve receives a control signal from said electronics element;

3) said control signal is derived from said electrical flow rate signal; and

4) upon receipt of said electrical flow rate signal from said flowmeter indicating an oxygen flow rate below a predetermined threshold, said solenoid valve is caused to open by said control signal from said electronics element.

2. The apparatus of claim 1, wherein;

a) said inlet is connected to a source of pressurized air; and

b) said outlet line is connected to an airways line supply circuit of a user.

3. The apparatus of claim 1, wherein said solenoid valve and said calibrated restriction are located, with respect to each other, in series.

4. The apparatus of claim 1, wherein said flowmeter comprises a hot-wire mass flowmeter.

5. The apparatus of claim 1, further comprising a switching valve, wherein said switching valve is connected to an auxiliary source of pressurized oxygen and to said outlet line.

6. The apparatus of claim 1, wherein said adsorber comprises a lithium zeolite.

7. The apparatus of claim 6, wherein said lithium zeolite comprises an LiLSX.

8. The apparatus of claim 1, further comprising a pressure-reducing device between said inlet and said PSA unit.

9. The apparatus of claim 1, further comprising a buffer tank connected to said outlet line.

10. The apparatus of claim 9, wherein said buffer tank forms a structural component of said generator.