FIELD: machine building.
SUBSTANCE: procedure for fabricating set of heat-hydro-insulated pipe diminishing pieces consists in connecting diminishing piece with various diametre branches of working pipe for each pipe sub. Hydro-insulation is fabricated separately in form of a pipe-casing of a sectional structure conditionally identical by shape to working pipe subs. Diminishing pieces of working pipes are centred. There are installed wires of on-line remote control system. The said hydro-insulation is conjugated with working pipe subs. Ends of hydro-insulation are sealed with process plugs. At least two-component foamed solidificated mixture is poured as a layer of heat insulation. Further mixture is conditioned; and process plugs are removed. Set of pipe diminishing pieces is fabricated within ranges of values of diametres of working pipe branches with smaller diametres from 25 to 230, preferably, from 38 to 219 mm and branches with bigger diametres from 65 to 435, preferably, from 76 to 426 mm selectively correlating to them in ranges of diametres of the working pipe. Thus there are created combinations of from one to ten, preferably, to six diminishing pieces with the same branch of the working pipe of smaller diametre. Change of insulation of working pipe volume with hydro-insulating material is from 1.5-0.16 to 0.3-0.1, wherein the first interval is ratio of specific volume of hydro-insulation to a unit of payload volume of reference running metre of a smaller diametre pipe branch connected in the pipe sub. The second interval is ratio of specific volume of hydro-insulation to a unit of payload volume of reference running metre of a bigger diametre pipe branch. Also at least part of pipe diminishing pieces with ratio from 1.3 of bigger to smaller of diametres of the pipe-casing are made with seamless hydro-insulation out of work-pieces of the pipe-casings of preferably round-cylinder configuration of smaller diametre by means of non-destructive increase of diametre with specified gradient of increment per unit of axial height of transient zone into time unit and with at least partially compensated decrease of wall thickness while re-distributing material in a deformed zone of the pipe diminishing piece. Each diminishing piece made according to this procedure consists of working, preferably, metallic pipes sub and of hydro-insulation in form of the pipe-casing of the sectional structure conditionally identical to shape of the diminishing piece with diametre exceeding relative diametres of the said working pipe diminishing piece by thickness required and sufficient to the protective layer of heat insulation arranged underneath; also the layer is formed out of two-component foamed solidificated mixture of calculated density in the middle of the layer not less, than 60 kg/m3, and it is equipped with wires of the on-line remote control system.
EFFECT: facilitating versatility, process simplicity and efficiency of production of set of heat-insulating pipe diminishing pieces, design of which ensures reduced heat losses and increased reliability of pipeline operation in whole.
24 cl, 16 dwg
