FIELD: construction industry, medicine and housekeeping, in particular, production of reservoirs with wall floating, when reservoir is filled. SUBSTANCE: vessel is made in the form of flexible impermeable enclosure composed of parts hermetically connected and cut from thermoplastic polymeric film or rubberized fabric. Vessel has bottom and wall with top defining edge cavity filled with gas. Enclosure has hermetically sealed air system made from at least two communicating bottom and edge cavities. Design volume of edge cavity is equal to that of liquid having weight equal to that of vessel. Design volume of bottom cavity exceeds that of edge cavity by amount equal to volume of guarantee part. System is filled with an amount of gas occupying, at minimum operating temperature and maximum operating pressure of ambient gas, the volume equal to design volume of bottom cavity. Each part of system has yielding heat-insulating plate positioned in loose state. All mentioned properties of vessel provide guaranteed lifting of vessel wall to nominal level, when it is filled with liquid or bulk substance, and stable position of wall. Method involves thermal diffusion welding of parts cut from thermoplastic polymeric film to produce vessel; filling vessel with respective liquid to nominal level; regulating excessive pressure in air system to obtain nominal value by means of regulating opening; sealing regulating opening to maintain excessive pressure in edge cavity at nominal value during filling of vessel to nominal level providing floating of edge. EFFECT: increased efficiency, improved strength and hygienic properties of vessel and repairability of vessel by user even in home conditions. 6 cl, 3 dwg
