Method and apparatus for artificial ground freezing
AssigneeLayne Christensen Company
InventorsGeorge Briley, Joseph A. Sopko
Life of this patent
Estimating the term…
Abstract
A ground freezing method and system which circulates refrigerated heat transfer fluid through freeze pipes in the ground at a low temperature of at least −52° C. (−62° F.) to minimize drilling for the freeze pipe installation. The heat transfer fluid is preferably aqua ammonia (ammonium hydroxide) because of its beneficial characteristics in this application. The circulating heat transfer fluid is preferably cooled by a refrigeration system that includes low and high stage cycles arranged in a cascade relationship and using ammonia or another refrigerant in the high stage refrigeration system and carbon dioxide as the refrigerant in the low stage refrigeration system.
Claims20
Ground freezing apparatus comprising:
- a high stage refrigeration system and a low stage refrigeration system arranged in a cascade relationship;
- a first heat exchanger using a first refrigerant in said high stage refrigeration system to extract heat from a second refrigerant in said low stage refrigeration system;
- a plurality of freeze pipes in the ground;
- a circulation path extending through said freeze pipes having a low temperature heat transfer fluid circulating therein to freeze the ground in proximity to said freeze pipes;
- and
- a second heat exchanger through which said circulation path passes, said second heat exchanger using said second refrigerant to extract heat from said heat transfer fluid for cooling thereof.
In a system for ground freezing using spaced apart freeze pipes embedded in the ground and a heat transfer fluid pumped through a circulation path extending through said freeze pipes to freeze the ground around the pipes, the improvement comprising:
- a refrigeration system including a heat exchanger through which said circulation path passes, said refrigeration system being arranged to cool said heat transfer fluid to a temperature below about −52° C. (−62° F.) when said heat transfer fluid is passed through said heat exchanger along said circulation path.
A method of artificially freezing ground in which a plurality of spaced apart freeze pipes are embedded, comprising:
- cooling a selected heat transfer fluid to a temperature below about −52° C. (−62° F.);
- and
- circulating said heat transfer fluid through said freeze pipes to freeze the ground in proximity thereto.
Dependencies are inferred from the claim text.