R.G. Hansen & Associates' demand
flow cryostat is a miniature, self-regulating device designed primarily
to minimize consumption of high-pressure gas. Operating times are
increased by at least a factor of 2 at low tank-charge pressures
(2,000 psi), and by factors of 10 or more at high pressures (5,000
to 10,000 psi), as compared with fixed orifice cryostats.
Relatively
small supply tanks can be used with demand flow cryostats to decrease
system weight and volume, and extended operating times can be obtained
with conventional-sized tanks. A tank pressure regulator is not
required. Demand flow cryostats are equipped with solid particle
inlet filters which prevent accidental plugging from dust or dirt.
Gas
Supply
Heat Load
Temperature
The
gas supply to the cryostat is normally commercial, high purity,
extra dry, water-pumped Nitrogen, MIL-N- 6011, Grade F. Units are
also available for use with Argon (87K).
A
thermostatic control element in the cryostat senses the liquid level
in the detector/dewar and operates a self-contained valve in response
to changes in heat load and ambient temperature. The demand flow
cryostat will adjust for varying heat loads up to 2 watts. The system
is completely self-contained; no electrical connections are required.
Fluctuation
Operating
System performance
can be affected by temperature fluctuations of the demand flow cryostat.
Our standard line of demand flow cryostats, however, shows temperature
fluctuations of less than 1 K/second.
The
demand flow cryostat will operate successfully over a wide range
of ambient temperatures; -55° C to 70° C is usual.
