US 4,377,402 A · CO.sub.2 Snow-making process

Abstract

Preparatory to its supply to snow horns, high-pressure liquid CO.sub.2 flows through a heat-exchanger where it is cooled by R-13 refrigerant, reducing the temperature of the high-pressure liquid to about -60.degree. F. at normal use rates. R-13 refrigerant is compressed and condensed against R-502, which is in turn compressed and condensed at ambient air temperature. Subcooled liquid CO.sub.2 at about 300 psig. provides an additional 7 weight percent snow over such liquid at 0.degree. F. A control system on each snow-making apparatus monitors the temperature of the subcooled liquid CO.sub.2 just upstream of expansion devices at the snow horns, and depending upon the temperature which is sensed, the control system changes the duration of time that liquid CO.sub.2 is supplied to a snow-making hood to assure a metered quantity of CO.sub.2 snow.

Claims5

Dependent claims

A method of providing metered quantities of CO.sub.2 snow, which method comprises

supplying liquid CO.sub.2 from a source at a pressure between about 200 and about 325 psig.,
subcooling said liquid CO.sub.2 to a temperature at least about 20.degree. F. below the equilibrium temperature thereof at said pressure by heat-exchange with a refrigerant having a lower temperature provided by a mechanical refrigeration unit,
periodically expanding said subcooled liquid CO.sub.2 by passage through expansion means to create CO.sub.2 snow for delivery to a receiver to be refrigerated,
monitoring the temperature of said subcooled liquid CO.sub.2 upstream of said expansion means, and
delivering a metered quantity of CO.sub.2 snow to each said receiver by automatically changing the duration of time of said periodic expansions relative to said temperature monitored.

2 more elements

Dependencies are inferred from the claim text.

CO.sub.2 Snow-making process

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CO.sub.2 Snow-making process

Life of this patent

Abstract

Claims5