FIELD: machine building.
SUBSTANCE: invention refers to machine building, particularly to procedures of fabricating heat-hydro-insulated diminishing pieces and also for proper designs of heat-hydro-insulated diminishing pieces used for connecting pipelines of different diametres and for connecting branches with simultaneous change of one diametre of pipeline to another. Procedure for fabricating set of heat-hydro-insulated pipe diminishing pieces consists in connecting diminishing piece with different diametre branches of working pipe for each pipe sub. Hydro-insulation is fabricated separately in form of a pipe-casing of a composed structure conditionally similar 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 200 to 950, preferably, from 219 to 920 mm and selectively correlating to them in ranges of diametres of working pipe branches with bigger diametres from 250 to 1050, preferably, from 273 to 1020 mm. Thus there are created combinations of from one to ten, preferably, to five diminishing pieces with the same branch of the working pipe of smaller diametre. Also there is facilitated volume protection of working pipe with hydro-insulating material. Volume protection is calculated from ratio of specific volume of hydro-insulation to a unit of payload volume of conditional running metre of the working pipe of each branch connected in a sub at the section of change from smaller diametre - not above 0.17, and not below 0.08 at the section of bigger diametre. Also at least part of pipe diminishing pieces with ratio of diametres of the pipe-casing bigger to smaller from 1.29 are made with hydro-insulation in form of a casing of complex structure out of work-pieces of the pipe-casings of bigger and smaller diametres by means of cutting. For this purpose cylinder not-flat wedges are cut out in a near-end zone of the branch of bigger diametre. Between each two nearest cuts there is left a cylinder blade. Side facets of adjacent blades are joined, mainly, by welding, and the branch of smaller diametre is connected, mainly, by welding. Each diminishing piece made according to this procedure consists of pipe sub and of hydro-insulation in form of the pipe-casing of complex 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. Each diminishing piece is equipped with wires of the on-line remote control system.
EFFECT: facilitating versatility, process simplicity and efficiency of production of set of heat-hydro-insulated pipe diminishing pieces, design of which ensures reduced heat losses and increased reliability of pipeline operation in whole.
24 cl, 16 dwg
