Device consists of helical heating coil inside cylinder and affixed at one end. Piston is fastened at other end and is free to move axially through cylinder. Electrical power extends coil when applied to conductors. Bimetallic stirrer may also be made in vane form

Canning, T. N.

English

NASA Technical Reports Server

February 1973	 B73-10029 
NASA TECH BRIEF S
Ames Research Center
- 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Bimetallic Devices for Stirring Fluids 
The problem: 
To stir reactive fluids such as liquid oxygen. 
The solution: 
Use an internally heated bimetallic pump to circu-
late the fluid. 
How it's done: 
One example of the bimetallic device, shown in the 
diagram as it would be installed in a fluid-storage tank, 
consists of a helical heating coil inside a cylinder and 
affixed at one end. At the other end of the heater coil 
is fastened a piston which is free to move axially 
through the cylinder. When electrical power is ap-
plied to the, conductors inside the heating coil, the 
coil extends. The extension causes the piston to move 
toward the end of the cylinder where orifice A is 
located. The piston movement forces the fluid to flow 
out of orifice A and into the tank containing the re-
maining fluid to be stirred; at the same time, fluid is 
drawn into the cylinder at orifice B. After a suitable 
interval of operation, the electrical power is turned 
off and the spring coil is cooled by conduction. This 
causes the coil to contract, returning the piston toward 
the end of the cylinder containing the spring and 
orifice B, expelling the fluid from that end of the 
cylinder and refilling the cylinder at orifice A. Thus, 
heating and stirring of the contents of the fluid-storage 
tank is effected. 
The bimetallic stirrer may also be made in the form 
of a vane which is moved by the bimetallic member 
supporting it. A bistable bimetallic "cricket" will eject 
spurts of fluid alternately as the "cricket" snaps from 
one stable position to the other upon heating and 
cooling.
Conductors 
Low K Metal 
Insulation 
High K Metal 
Note: 
No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Ames Research' Center 
Moffett Field, California 94035 
Reference: B 73-10029 
Patent status: 
Inquiries concerning rights for the commercial use 
of this invention should be addressed to: 
NASA Patent Counsel 
Mail Code 200-IA 
Ames Research Center 
Moffett Field, California 94035 
Source: Thomas N. Canning 
Ames Research Center 
(ARC-10441) 
Category 08 
	
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Bimetallic devices for stirring fluids

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