Ruggedized, Condition-Based Maintenance for Vacuum Insulation Systems
Navy SBIR 2016.1 - Topic N161-024
NAVSEA - Mr. Dean Putnam - [email protected]
Opens: January 11, 2016 - Closes: February 17, 2016
N161-024 TITLE: Ruggedized, Condition-Based Maintenance for Vacuum Insulation Systems
TECHNOLOGY AREA(S): Ground/Sea Vehicles
ACQUISITION PROGRAM: PMS320, Electric Ships Office; PMS501 Littoral Combat Ship Program Office
The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 5.4.c.(8) of the solicitation. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.
OBJECTIVE: Develop a small-scale vacuum maintenance device for use in Navy cryogenic and superconducting applications.
DESCRIPTION: The demand for lightweight, high current density (gravimetric and volumetric) electrical power architecture is driving development of key superconducting technologies including motors, generators, power cables, and degaussing cables. All of these technologies rely on a vacuum insulation system to minimize heat leak into the cryogenic space. A vacuum will degrade over time due to outgassing of materials from thermal cycling and to slow losses of vacuum pressure. As the vacuum degrades, the performance of Multi-Layer Insulation decreases and higher heat leak into the cryogenic system occurs. The result is either the inability to maintain the cryogenic environment (thereby reducing the superconducting state), or the cryogenic system output needs to be increased to keep up with the higher heat load.
The Navy is currently considering the use of distributed high temperature superconducting (HTS) systems such as HTS degaussing (Ref. 1), HTS motors and generators, or HTS power distribution systems. These systems contain cryogenic spaces insulated with multi-layer insulation (MLI) and held to deep vacuum levels of 1x10-4 torr or better. The vacuum space in the cryostat is a necessary part of the thermal insulation solution that minimizes the heat transfer between the volume containing the cryogenic fluid and atmospheric temperatures. Maintaining this deep vacuum level in the cryostats is essential to the operation of these systems. As the vacuum degrades over time, the reduction in insulation increases the heat load to the system thereby putting additional strain on the limited available cryogenic cooling. This increase in the heat load to the cryogenic system will cause an increase in the operating temperature of the entire system and will decrease the performance of the superconductor.
During the course of normal operations, shipboard systems will be powered down. This will result in periodic thermal cycling which will release cryo-pumped contaminants. These natural warming cycles will degrade the vacuum further, leading to additional heat loads if not pumped out. Over time, materials in the vacuum space naturally outgas, requiring the need for gettering material to trap the released contaminants and manage the rate of outgassing. Typically, vacuum spaces are periodically maintained by manual intervention every 5-10 years for each vacuum space. This maintenance can be eliminated through the integration of an autonomous vacuum system. A cost avoidance of up to $550K per ship can be realized over the designed 30-year life of each ship by incorporating the vacuum maintenance system. The integration of this component will also increase damage tolerance of the system through active pumping; an approach commonly used to manage small vacuum leaks in vacuum insulated systems and still achieve the highest level of system efficiency. A ruggedized, periodically activated, vacuum maintenance system that maintains a high vacuum level in the cryostat and increases the mean-time between maintenance (MTBM), will reduce the total ownership cost of HTS systems.
Current state of the art technologies incorporate ion pumping technology, turbomolecular pumps (Ref. 2 and 3), and getter materials to obtain and maintain vacuum levels. The Navy is looking for a novel device using any of these or similar technologies to periodically pump or maintain the vacuum to an acceptable level of 1x10-4 torr over a 30 year ship life. The device needs to be capable of sensing degradation in the vacuum level of a system and activate the compact vacuum system when the vacuum level is greater 1x10-3 torr. The vacuum system must be able to pull vacuum down from 1x10-1 torr to 1x10-6 torr, and will discharge to atmospheric pressures (foreline pressure = 760 torr). The vacuum system must connect to a cryostat and be easily installed or replaced. The vacuum space must not lose vacuum pressure if the pump experiences a loss of power or if the pump is in a standby mode. In addition, the vacuum pump must be small (approximate volume of 35in3, or 3"diameterby 5"long) and lightweight (about 2-5 lbs. or less). Given the environment, the vacuum pump must be immune to electromagnetic interference (EMI), and should be rugged in order to handle a shipboard environment. Any proposed solution must be designed to survive shock and vibration qualification testing by the Navy. Finally, the vacuum pump must be affordable ($1,000 - $2,000) since there will be 50-100 units per ship for a full ship degaussing system.
PHASE I: The company will develop a concept for a small-scale vacuum maintenance device for use in Navy cryogenic and superconducting applications. They must demonstrate the feasibility of a novel vacuum pump to operate with Navy cryogenic systems as defined in the description. The company will perform bench top experimentation, where applicable, as a means of demonstrating the identified concept and establish validation goals and metrics to analyze the feasibility of the proposed solution. The Phase I final report shall capture the technical feasibility and economic viability for the proposed concept that can be matured further if awarded a Phase II. The Phase I Option, if awarded, will include an initial layout and capabilities description to build the prototype in Phase II.
PHASE II: The company will develop, fabricate, and demonstrate a small-scale vacuum maintenance device prototype based on the work conducted in Phase I and the Phase II Statement of Work (SOW). In the company’s laboratory environment, they will demonstrate that the prototype meets the performance goals established in Phase I and the Phase II SOW. The final prototype operation will be verified in a representative laboratory environment and results provided and evaluated. A cost benefit analysis and a Phase III installation, testing, and validation plan will be developed. Based on lessons learned in Phase II through the prototype demonstration, a substantially complete design of a vacuum pumping system should be completed and delivered that would be expected to pass Navy qualification testing.
PHASE III DUAL USE APPLICATIONS: The company will be expected to support the Navy in transitioning the small-scale vacuum maintenance device technology for Navy use onboard ship. This includes teaming with appropriate industry partners to provide system integration and to provide a fully qualified vacuum pump. A reliable small-scale vacuum pump may be of use in land based HTS power cables and power delivery applications. When land based HTS power cables transition from R&D projects to commercial installations, maintaining vacuum levels will help lower the maintenance of the system alleviating the need for repeated vacuum processing.
1. Kephart J., Fitzpatrick B., Ferrara P., Pyryt M., Pienkos J., Golda E.M., "High Temperature Superconducting Degaussing From Feasibility Study to Fleet Adoption", IEEE Transactions on Applied Superconductivity, Vol. 21, Issue 3, pg 2229 – 2232, June 20
2. Hsieh F.C., Lin P.H., Liu D.R., and Chen F.Z., "Pumping performance analysis on turbomolecular pump", Vacuum, Vol. 86, Issue 7, pg 830–832, February 2011.
3. Shirinov A., Oberbeck S., "High vacuum side channel pump working against atmosphere", Vacuum, Vol. 85, Issue 12, pg 1174-1177, June 2011.
KEYWORDS: Vacuum pump for superconducting systems; getter materials; superconductor; cryostat; high-temperature superconductor (HTS); vacuum maintenance of cryogenic systems
TPOC-1: Jacob Kephart
Email: [email protected]
TPOC-2: Steven Krider
Email: [email protected]
Questions may also be submitted through DoD SBIR/STTR SITIS website.