Equipment and method for surface treatment by jets of cryogenic fluid

A working installation using at least one jet of fluid at cryogenic temperature under high pressure comprising:

• a source (1) of fluid at cryogenic temperature fluidly connected to a mobile tool (4) having one or more fluid dispensing nozzles (11) configured to dispense one or more jets of said fluid at cryogenic temperature under high pressure, and
• a first protective enclosure (20) fitted around the mobile tool (4) and fluidly connected to suction device (25), said first protective enclosure (20) comprising an open lower end, situated at the side of the fluid dispensing nozzle or nozzles (11), so as to form a suction hood around the tool (4),
• wherein the first protective enclosure (20) further contains a gaseous sealing element (23) suitable for and designed to form at least one protective gaseous barrier at least at the lower end of the first protective enclosure (20) and on at least a part of the periphery of said first protective enclosure (20), said gaseous sealing element (23) comprising:
• a second protective enclosure (23) fitted around at least a part of the first protective enclosure (20) and open at the lower end of the first protective enclosure (20), and
• a dry gas supply source (26, 27) fluidly connected to said second protective enclosure (23) and configured to supply the interior of said second protective enclosure (23) with a dry gas.