NASA STTR 2005 Solicitation


RESEARCH SUBTOPIC TITLE:Batteryless, Wireless Remote Sensors
PROPOSAL TITLE:Passive Wireless Cryogenic Liquid Level Sensors Using Orthogonal Frequency Coded Acoustic Wave Devices

NAME: Applied Sensor Research & Development Corporation NAME:University of Central Florida
ADDRESS:Unit 2, 1195 Baltimore-Annapolis Blvd. ADDRESS:4000 University Boulevard
CITY:Arnold CITY:Orlando
STATE/ZIP:MD  21012-1808 STATE/ZIP:FL  32816-8005
PHONE: (410) 544-4664 PHONE: (407) 823-2414

Leland  P Solie

TECHNICAL ABSTRACT ( Limit 2000 characters, approximately 200 words)
This proposal describes the continued development of passive wireless surface acoustic wave (SAW) based liquid level sensors for NASA application to cryogenic liquid level sensing. Orthogonal Frequency Coded (OFC) SAW devices have been demonstrated as passive wireless temperature sensors in NASA Contract NNK04OA28C, and are being further developed under NNK05OB31C. The liquid level sensors use damping of the acoustic wave caused by mass loading of the liquid to produce fast, reversible liquid level sensors. The Phase I research successfully demonstrated operation of these devices as liquid level sensors in selected liquids of interest at cryogenic temperatures. Stability of selected commercially available SAW devices was confirmed, both when exposed to various (extreme and gradual) temperature changes, and upon repeated exposure to liquid nitrogen. The reversibility of the device response was confirmed. Phase I demonstrated the technical feasibility of using these sensors for cryogenic liquid level monitoring of low to moderate pressure liquids (under 500 psi). Phase II will result in prototype product development.

POTENTIAL NASA COMMERCIAL APPLICATIONS ( Limit 1500 characters, approximately 150 words)
The primary NASA application for the proposed sensors would be in a wireless multisensor system for liquid level measurement in storage tanks for cryogenic liquids. With uniquely identifiable sensors, this system could use low cost sensors mounted at numerous levels within a tank to remotely detect the presence (and therefore for terrestrial tanks the level) of liquid within the tank. Wireless sensor interrogation requires only one tank penetration for the transceiver antenna, minimizing heat transfer pathways. Resolution of liquid level is fine due to small sensor size. The proposed sensors could also monitor temperature in the headspace above the liquid.

POTENTIAL NON-NASA COMMERCIAL APPLICATIONS ( Limit 1500 characters, approximately 150 words)
While the market size for potential applications needs to be evaluated, it is clear that the proposed sensors can be used commercially for liquid level monitoring within storage tanks for volatile liquids, and to monitor temperature in the headspace above such liquids. Since OFC SAW sensors operate over a wide range of temperatures, commercial applications may include both cryogenic and higher temperature liquid storage. Passivation of the sensor surface may make this approach feasible for use in caustic volatile liquids. Reversiblity of sensor response when the liquid level in the tank drops requires the liquids monitored to be volatile.

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Form Printed on 01-23-07 12:19