Treadwell Supplies Oxygen Generator Components for Nuclear Subs
Submarines travel underwater, but they all need oxygen. Diesel-electric submarines need it for their engines, and must surface to get it, though modern AIP (Air Independent Propulsion) supplemental systems allow one to cruise at moderate power for over a week without surfacing. Nuclear-powered submarines could cruise underwater at full power for years, of course, as their engines do not need air. Their crews, however, do. Hence Electrolytic Oxygen Generators (EOGs), which break up water molecules and keep the oxygen for use aboard ship.
Treadwell Corp’s Model 6L16 EOG was first introduced in 1965. It breaks up distilled water by passing an electric current through an electrolyte solution (30% potassium hydroxide) in 16 high-pressure cells, connected in series. This equipment can produce 150 standard cubic feet per hour of oxygen, and variants remain the primary oxygen producers aboard the USA’s SSN-688 Los Angeles Class fast attack submarines and SSBN-726 Ohio Class ballistic missile submarines. Treadwell also produces Oxygen Generation Plants (OGPs) for the new SSN-21 Seawolf Class fast attack submarines, which include OGP electrolysis modules that depend on proton exchange membranes for oxygen separation.
The US Navy is moving to upgrade both of these systems.
Oxygen Generation Upgrades
The upgrade program within the USA’s all-nuclear submarine fleet is a dual-track effort. A program was launched in 1997 to upgrade existing 6L16 EOGs to a digital control system, as Advanced/Automated EOGs (AEOGs). Advantages include the automation of often-used actions; operator prompts for required actions, built-in diagnostics, data & trend analysis, and software interlocks; reduced cost; the elimination of over 12,000 parts; and less noise. Buying and installing new components to upgrade these systems is part of a program to continue upgrading EOGs for extended life, lower life cycle costs, and better reliability.
Treadwell’s Low Pressure Electrolyzer (LPE) models use the proton exchange membrane approach instead of high-pressure cells, and can produce 170 or 225 standard cubic feet per hour, depending on the model used. Going forward, the new LPEs will operate as the primary oxygen producers aboard the SSBN-726 Ohio Class ballistic missile submarines, as well as the SSN-21 Seawolf Class fast attack submarines.
The OGP models currently aboard SSN-21 fast attack submarines also have a capacity of 225 SCFH, but the new LPEs can produce oxygen at normal interior pressure, instead of requiring pressures up to 3,000 psi like the EOGs or OGPs. Development is still underway, but the LPE systems are expected to be about 1/3 the volume of the EOG/OGP systems. Space is hugely valuable in submarines, where every cubic inch counts; the LPEs will also offer better reliability, maintainability, safety, and ease of operation.
America’s Virginia Class submarines use an Integrated Low Pressure Electrolyzer (ILPE) of their own, produced by United Technologies subsidiary Hamilton Sundstrand. They are working with Distributed Energy Systems on next-generation electrolysis cell stacks.
Unless otherwise specified, The Naval Surface Warfare Center, Carderock Division’s Ship System Engineering Station in Philadelphia, PA issues these contracts.
Jan 24/08: Treadwell Corp. in Thomaston, CT won a $62 million firm-fixed-price, indefinite-delivery/indefinite-quantity contract for up to 29 Low Pressure Electrolyzers, plus Low Pressure Electrolyzer Simulators, associated installation services, and training and technical data. The systems will replace the Model 6L16 Electrolytic Oxygen Generator and Oxygen Generating Plant aboard SSBN/SSGN-726 Ohio Class ballistic missile and special forces/strike submarines, and SSN-21 Seawolf Classfast attack submarines.
Work will be performed in Thomaston, CT and is expected to be complete by January 2011. This contract was competitively procured via the Federal Business Opportunities website, with 2 offers received by the Naval Surface Warfare Center Carderock Division, Ship Systems Engineering Station in Philadelphia, PA (N65540-08-D-0007). Since United Technologies’ subsidiary Hamilton Sundstrand makes ILPEs for the Virginia Class boats, they can be assumed to have been the other bidders.
March 14/07: Treadwell Corporation in Thomaston, CT received a $9.2 million firm-fixed-price contract for furnishing new auxiliary cubicles and microprocessor controllers for the US Navy’s model 6L16 electrolytic oxygen generators (EOG). These changes will turn the EOGs into AEOGs. Work will be performed in Thomaston, CT and is expected to be complete by April 2009. This contract was not competitively procured (N65540-07-C-0001).
March 30/06: Treadwell Corp. in Thomaston, CT received a $12.6 million firm-fixed-price contract for auxiliary cubicles and microprocessor controllers for model 6L16 electrolytic oxygen generators (EOG). Acquisition of the new components is part of the AEOG upgrade program, resulting in extended life, increasing reliability and reducing life-cycle costs. Work will be performed in Thomaston, CT and is expected to be complete by September 2008. The contract was not competitively procured (N65540-06-C-0014).
Aug 23/05: Treadwell Corp. in Thomaston, CT received a $12.3 million firm-fixed-price contract for Auxiliary Cubicles and Microprocessor Controller components for Model 6L16 Electrolytic Oxygen Generators (EOG). These changes will turn the EOGs into AEOGs. Work will be performed in Thomaston, CT and is expected to be completed by September 2007. The contract was not competitively procured. The Naval Surface Warfare Center, Carderock Division, Ship System Engineering Station in Philadelphia, PA issued the contract (N65540-05-C-0029).
June 28/04: Treadwell Corp. in Thomaston, CT received a $13.8 million firm-fixed-price contract to provide new auxiliary cubicles and microprocessor controller components for SSN-688/SSBN-726 Class, Model 6L16 Electrolytic Oxygen Generators (EOG). These changes will turn the EOGs into AEOGs. Work will be performed in Thomaston, CT and is expected to be complete by November 2006. The contract was not competitively procured (N65540-04-C-0032).