Two-stage Scroll Roughing Pump Awarded Phase I SBIR Funding

The US Navy, in connection with their effort to explore ruggedized, condition-based maintenance for vacuum insulation systems, has awarded Phase I SBIR funding to Air Squared to develop a compact two-stage scroll roughing pump with an integrated turbomolecular backing pump.

Concept Air Squared Turbomolecular Pump with Two-stage Scroll Vacuum Pump

Figure 1: Concept Air Squared Turbomolecular Pump with Two-stage Scroll Vacuum Pump

Broomfield, CO — The US Navy has identified an autonomous vacuum system as a key component to eliminating maintenance on current shipboard vacuum isolation systems. The cost of maintenance for current vacuum insulation systems is estimated at $550,000 US per ship over the life of the ship. While autonomous vacuum systems already exist, they are very large, require excessive power, and are expensive to purchase and operate. With Phase I Small Business Innovation Research (SBIR) funding, Air Squared will demonstrate a small-scale vacuum maintenance device that could ultimately be used in US Navy cryogenic and superconducting applications.

The Phase I effort takes a multi-stage vacuum approach, leveraging two pumping technologies, to deliver a compact, robust, and autonomously-driven vacuum system. The system integrates an Air–Squared designed two-stage scroll vacuum pump with a proven turbomolecular backing pump (Figure 1). The two-stage scroll vacuum pump acts as a roughing pump, delivering 50 mTorr vacuum from atmospheric pressure, and then the turbomolecular backing pump delivers 0.1 mTorr vacuum from 50 mTorr.

Air Squared’s patented two-stage scroll pump (Figure 2) allows for the miniaturization of positive displacement scroll vacuum pump technology without degradation in vacuum performance. Integrating this technology with existing off-the-shelf miniature turbomolecular technology provides a pathway to realizing a compact and cost-effective autonomous vacuum system, without sacrificing performance or reliability.

The US Navy has identified several Critical Performance Metrics (CPM) for the vacuum system:

Two-stage Scroll Vacuum Pump, Exploded View

Figure 2: Two-stage Scroll Vacuum Pump, Exploded View

  1. Provides a vacuum below 1×10-4 torr (0.1 mTorr)
  2. Pumps down the system from 0.1 Torr (100 mTorr) to 1×10-6 Torr (0.001 mTorr)
  3. Discharges to atmospheric pressure (760 Torr)
  4. Offers a size less than 35 in3 (or 3 inches in diameter by 5 inches long)
  5. Costs less than $2,000 US
  6. Weighs less than 5 pounds
  7. Connects to the cryostat
  8. Is easy to install or replace
  9. Sustains performance over a thirty-year ship life
  10. Senses degradation in the vacuum level
  11. Loses pressure if the pump experiences power loss
  12. Is immune to electromagnetic interference
  13. Handles a rugged shipboard environment
  14. Survives US Navy shock and vibration qualification

While all CPMs will be considered throughout development, the primary goal of the Phase I effort is to accomplish CPMs 1 through 6. Air Squared will first evaluate appropriate turbomolecular vacuum pumps and existing Air Squared two-stage scroll vacuum pumps. A full system performance model will then be executed over a range of system configurations and operating parameters to identify potential preliminary system architectures. Finally, fabrication and extensive testing of the selected system architectures will then demonstrate the feasibility of CPMs 1 through 6.

About Air Squared

Air Squared is the industry leader in oil-free scroll design and manufacturing. By introducing a simple design with fewer moving parts, scroll technology has established itself as a highly efficient, very reliable, cost-effective alternative. Through a growing line of compressors, vacuum pumps, and expanders, Air Squared makes the many advantages of oil-free scroll technology available to OEMs worldwide.

This material is based upon work supported by the Department of Defense under SBIR Topic: N161-024-0557. Any opinions, findings, conclusions, or recommendations expressed in this material are those of the author(s) and do not necessarily reflect those of the Department of Defense.

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