Screw pump rod coupler
FIELD: engines and pumps.
SUBSTANCE: invention relates to couplers of pump rods for screw pump drive. Said coupler comprises captive nut with inner ledge on one side and internal thread on opposite side, rod body, captive nut and locating nut. Rod body has external thread, wedge-like slit and wedge-like ledge at opposite end. Note here that captive nut and guide captive sleeve are fitted on the rod of wedge-like ledge, locating nut being fitted on the body to contact with its inner ledge. Wedge-like ledge can be arranged in wedge-like slot of adjacent rod at its coupling with the guide captive sleeve.
EFFECT: higher torsion strength and breaking point.
5 cl, 2 dwg
The PURPOSE of the INVENTION
The invention relates to rod devices and is used in oil wells in the oil fields, especially in special devices sucker rods to drive the screw pumps.
The LEVEL of TECHNOLOGY
The usual pump rod to drive the screw pumps at the fields include General pump rod and rod with fan-shaped tip. Two sucker rods are connected by a common sleeve. One end of the sleeve is connected by a threaded end of one rod and the other end is connected by a thread with the corresponding end of the other of the pump rod. Because the connection uses only thread, sucker rod pumps have low strength in torsion and are mainly used in downhole pumps with reciprocating linear motion. When the sucker rods are fan-shaped end walls, the rotation of the screw pump is passed well, but the connection between the sleeve and the pump rod quickly weaken, which leads to a crash, thereby reducing the efficiency of screw pumps.
In connection with the above-described problems, one objective of the invention is to provide such a connection rod screw pump, which has a high strength and resistant to torsion loads on the gap.
To achieve the above objectives, in accordance with one of the options from which retene provided by the connecting device of the pump rod screw pump, containing the pivot rod located therein the guide cap sleeve, at one end of the core rod is made wedge-shaped groove and an external thread, and at the other end of the rod the rod is made wedge-shaped protrusion, which is located near the positioning nut which is in engagement with the guide collar sleeve forms a plug connection on the other end of the pivot rod.
For greater reliability prevent broken rod rod rod positioning between the nut and wedge-shaped protrusion is internal nut.
Thus, the guide cap sleeve stably fixed in the axial direction by positioning the nut and the inner nut.
Outer cap nut is located on the pivot rod and is arranged to interact with the guide collar sleeve. Guide coupling sleeve is securely fastened in the axial direction using the Union nut.
At one end of the guide cap sleeves are made internal to the ledge with the opportunity to interact with the positioning nut and the other end of the guide collar sleeve has an internal connecting thread. The internal threaded connection of the guide cap sleeve one rod interacts with the external threaded connection terminal each is th rod. Thus, the two rods are connected through the guide coupling sleeve, which fixes them in the axial direction by positioning nuts.
Plug connection made in the form of a threaded connection, it is convenient for disassembly.
Advantages of the invention are given below. The connecting device of the pump rod for screw pump comprises a pivot rod located therein the guide cap sleeve, at one end of the core rod is made wedge-shaped groove and an external thread, and at the other end of the rod the rod is made wedge-shaped protrusion, which is located near the positioning nut which is in engagement with the guide collar sleeve forms a plug connection on the other end of the pivot rod. Wedge-shaped groove of one of the pivot rod is engaged with a V-shaped projection of the other rod rod, thus achieving a reliable connection of the two rods, pump rods. The connection area of the two rods rod surrounded by a guide collar sleeve that captures two pump rod in the axial direction.
It provides fine adjustment of the length of the rod, backlash-free connection of the rods of the rod and reliable kontrolka. As a result, the connection can transmit large torque, thereby increasing the strength of the torsion su is th column bars for screw pump wells. In addition, a positioning nut inner nut and spanner lock nut guide cap sleeve in the axial direction. Thus, the team of the pump rod will not relent and will be resistant to rupture, thus avoiding accidents. This increases the efficiency and the production cost is reduced. Therefore, the invention creates a technical result.
BRIEF DESCRIPTION of DRAWINGS
In Fig. 1 shows a structural diagram of a connecting device of the pump rod, and Fig. 2 is a structural diagram of a connection of two rods of the pump rod.
In the drawings, the following symbols are used: Wedge-shaped groove 1; Outer thread 2; Rod 3 rod; cap nut 4; Inner tab 5; Positioning nut 6; Inner nut 7; Wedge-shaped protrusion 8; Guide cap sleeve 9; connecting the internal thread 10. The connecting device of the pump rod screw pump includes a guide collar sleeve 9 with the inner protrusion 5 on the one hand and with the internal connection thread 10 on the other hand, the rod 3 rod made with external thread on both sides, and with a wedge-shaped groove 1 at one end and a V-shaped projection 8 on the other end, the cap nut 4 and a positioning nut 6, however, the wedge-shaped in the stupa 8 on the rod 3 with Union nut 4 and the guide coupling sleeve 9, within which to contact her inner ledge 5the rod 3 is installed with a positioning nut 6, and the wedge-shaped protrusion 8 is made with the possibility of locating in a wedge-shaped groove 1 of the adjacent rod 3 when connecting the latter with the guide collar sleeve 9. The device has an internal nut 7 screwed from the side of the wedge-shaped protrusion 8 on the rod 3 to contact with the positioning nut 6. Union nut 4 is screwed on the rod 3 until contact with the rail cap sleeve 9. Internal tab 5the guide coupling sleeve 9 is arranged to communicate with a positioning nut 6. The connection of the guide collar of the sleeve 9 with the adjacent rod 3 made in the form of detachable connection of the external thread 2 of the latter with internal thread 10 of the coupling sleeve 9.
DETAILED DESCRIPTION of the INVENTION
As shown in Fig. 1, the connecting device of the pump rod screw pump includes a rod 3 rod and located thereon the guide coupling sleeve 9. Wedge-shaped groove 1 is located at one end of the rod 3 rod. External thread (screw connection) 2 near the wedge-shaped groove 1 is located at one end of the rod 3 rod, and a wedge-shaped protrusion 8 is located at the other end of the rod 3 rod. Positioning nut 6 is located near the Kli is Abednego ledge 8 and holds the guide cap sleeve 9, while allowing to quickly articulate (for example, threaded connection thread 2 and thread 10) adjacent rods 3 rods. The inner nut 7 is to move (for example, the thread on the rod 3 rod positioning between the nut 6 and a V-shaped projection 8. Union nut 4 is to move (for example, the thread on the rod 3 rod and holds the guide coupling sleeve 9. Tab 5located inside one end of the guide collar sleeve 9 to communicate with the positioning nut 6 and the other end of the guide collar sleeve 9 has an internal connection thread 10 for connection threaded connection threaded 2 from the upper end of the adjacent (matched) rod 3 rod.
The connection process shown in Fig. 1 and Fig. 2. A rod 3 rod are positioned successively Union nut 4 and the guide coupling sleeve 9. Positioning the nut 6 and the inner nut 7 davinciaudio during the rotation. Positioning the nut 6 and the tab 5the guide coupling sleeve 9 is fixed with the latest in the axial direction. After this wedge-shaped protrusion 8 of the first rod 3 rod enters the wedge-shaped notch 1 second rod 3 rod to achieve a connection of two rods 3 sleeve 9, spin-on thread 10 on the external thread 2 of the second terminal 3. When the coupling nut is 4 tightened, the sleeve 9 using a positioning nut 6, the inner nut 7 and the Union nut 4 is securely fixed in the axial direction, providing a reliable connection between two rods 3 rods each other. The claimed technical solution is to fine - tune and reliable kontrolka the length of the rod and to provide a backlash-free connection of the rods of the rod. This connection effectively improves the strength of torsion associated rods rod. The number of rods of rods is determined by the real needs, and thus, multiple series-connected rods rods form a single rod circuit. It should be noted that the examples are intended to describe and not to limit the invention. For the person skilled in the art it is obvious that without departure from the invention in its broader aspects may be changes and modifications are covered by the claims.
1. The connecting device of the pump rod screw pump containing the guide coupling sleeve with internal ledge with one hand and with the internal thread on the other hand, rod rod, made with an external thread, and a wedge-shaped groove at one end and a wedge-shaped protrusion on the other end, the cap nut and positioning the nut, in this case, the wedge is a prominent protrusion on the rod installed bolting and guide cap sleeve, within which to contact with its internal ledge on the rod is installed with a positioning nut and wedge-shaped protrusion is configured to fit in a wedge-shaped groove adjacent terminal when connecting the latter with the guide collar sleeve.
2. The connecting device according to p. 1, characterized in that it has an internal nut is screwed from the side of the wedge-shaped protrusion on the rod to contact with the positioning nut.
3. The connecting device according to any one of paragraphs. 1 or 2, characterized in that the cap nut is screwed on the rod to contact with the rail cap sleeve.
4. The connecting device according to claim 3, characterized in that the inner ledge of the guide cap sleeves are made interoperable with the positioning nut.
5.The connecting device according to claim 4, characterized in that the connection of the guide coupling sleeve with the adjacent rod made in the form of detachable connection of the external thread of the latter with internal thread spanner bushing.
FIELD: oil and gas industry.
SUBSTANCE: invention relates to drilling engineering and refers mainly to threaded connection of drill pipe joints used for geological surveying and oil well drilling. The threaded connection consists of a sleeve, a nipple and a slotted spring installed between the sleeve lip and thrust face of the nipple. At that a gap is formed between the sleeve lip and the nipple thrust face, this gap is liquidated in process of the connection tightening and spring compression and it is equal to the spring pitch and according to its parameters it corresponds exactly to the preset axial load to the inner thrust joint. Upon tightening of the connection the exact axial loads is provided to the outer thrust joint. Reliable functioning of both thrust joints allows increasing axial force of the threaded connection 1.5 times and improving its statistical strength and cyclic life.
EFFECT: provision of the exact preset loads to the inner and outer thrust joints, maintenance of their ratio within the whole operational period.
FIELD: machine building.
SUBSTANCE: group of inventions refers to a pipe component for a threaded joint. The joint on one end is fitted with a thread zone formed on its outer or inner periphery surface depending on the type of the threaded end: male or female. The said end comes to the end surface, and the thread zone along of at least one section comprises thread turns which, if considered in the longitudinal section passing through the pipe component axis, comprise the thread turn vertex, the thread turn base, a loaded side and a striking side. The width of the thread turn vertices decreases in the direction to the end surface while the width of the thread turn bases increases. If considered in the longitudinal section passing through the pipe component axis, the profile of loaded and/or striking sides comprises a central section of a continuous curve fitted with an inflection point. The said profile is convex at the thread turn vertex and concave at the thread turn base. Threaded joint is described as well.
EFFECT: higher reliability of threaded joint.
16 cl, 5 dwg
FIELD: oil and gas industry.
SUBSTANCE: connection of shaped tubes of well shutters includes shaped tubes with cylindrical ends, which are equipped with sleeved and nipple thread on mutually facing surfaces. Besides, there are sealing devices of the connection, which are made in the form of two elastic rings. One of the rings is installed in an expanded annular coupling end on the side of internal joint of thread between the mutually facing cylindrical surfaces of the threaded and annular sections. In the nipple end there is a constriction for the second elastic ring on the side of an external joint of thread between the mutually facing cylindrical surfaces of the threaded and annular sections. The external joint is made in the form of tightly adjoining and mutually facing conical tube surfaces. Above and/or below the threaded connection on the cylindrical section there is a constriction in the form of alternating annular bulges and cavities. An elastic cuff is welded on the outer surface of the constriction flush with the cylindrical section.
EFFECT: reducing stiffness of the connection cross section and excluding liquid flow between walls of the shutter and the well.
SUBSTANCE: on the entire length of useful thread there are two or more turns of the complete variation curved thread, in which tension along the average diameter of turns for specified value of fit tension is more than tension along the average diameter of turns of the appropriate reference standard conical thread. The side of the variation bent thread profile is a bent arched surface. The invention also relates to methods and devices for manufacturing of the external thread of the input pipeline, made as capable of tight fit, and also to the pair of fittings with thread of the input pipeline, made as capable of tight fit.
EFFECT: production of a tight threaded joint without usage of seals.
12 cl, 14 dwg
FIELD: machine building.
SUBSTANCE: connection includes "nipple" and "coupling", first elastomeric seal ring that includes integrated L-shaped metal reinforcing ring and second elastomeric seal ring between nipple and coupling equipped with reinforcing ring. First ring is located in first depression near coupling neck. Second ring is located in second depression inside the coupling located between first depression and coupling threaded part.
EFFECT: simplicity and reliability of assembly, increase of efficiency in the course of operation.
15 cl, 9 dwg
FIELD: machine building.
SUBSTANCE: insulated threaded pipe connection includes male element (1) with external thread (3) and female element (2) with internal thread (4) corresponding to external thread (3). One of the elements includes edge (5) passing behind thread (3) to free end of element (6). The other element includes cavity (10) for edge (5). Edge (5) includes the first zone (7) with peripheral surface facing the other element. In the first zone there located is the first insulating surface (13). The first insulating surface can be radially put with preload on the corresponding second insulating surface (11). The second insulating surface is located on peripheral surface of cavity (10) of the other element. Edge (5) has the second axially located zone (8) between the first zone (7) and free end of element (6). It includes the first radial supporting surface (14) facing the other element. The first radial supporting surface touches the second corresponding radial supporting surface (12). The second radial supporting surface is located on peripheral surface of cavity (10) of the other element. The first and the second zones (7, 8) are separated with the third zone (9) with radial stiffness that is lower than that of the first and the second zones (7, 8). The third zone (9) is capable of radial deformation towards the other element when pressure is applied to it. The third zone has minimum thickness in the range of 60% to 80% of edge thickness and axial length at the specified minimum thickness in the range of 0.25 to 5 mm.
EFFECT: resistance to sequential pressure loads is provided.
SUBSTANCE: drilling equipment comprises a female and a male parts, connected to each other by means of a threaded joint. The threaded joint comprises an inner trapezoidal thread in the female part and an outer trapezoidal thread on the male part. Each thread has a shape of a spiral ridge limited with the top and two lateral sides, a groove with a bottom. The groove stretches between two tops, besides, the thread ridge goes along multiple turns between the front and rear ends of the drilling equipment. The individual top of the thread touches upon an imaginary cylinder or a cone concentric with a central axis. At the same time the bottom of the groove of at least one of threads has a concave and a partially circular shape of a cross section at least along a part of the groove length. The individual top of the thread is transformed into lateral sides via concave radius transitions. These radii reduce in the axial direction from one end of the spiral ridge of the thread to the other end. At the same time the radius of the groove bottom increases in the same direction.
EFFECT: higher strength and service life of a threaded joint.
13 cl, 10 dwg
SUBSTANCE: self-drilling anchor bolt contains first and second ends, shaft provided with axis and located between the ends and anchor device being arranged along the first part of shaft close to the first end and provided with female thread interacting with male thread of shaft. At that the first end of anchor bolt is provided with drill bit and limit stop to restrict rotation of anchor device on shaft to support anchor device in free threaded connection on shaft during drilling. Limit stop contains connected support surfaces, one of them is located on drill bit, the other is on shaft, at that each support surface is formed by at least one upward-projecting wall.
EFFECT: improving anchor operating reliability.
16 cl, 17 dwg
SUBSTANCE: threaded element (EM; EF) of a part (T2; T1) comprises a free end (EL2; EL1) and at least the first (FE1; FI1) and second (FE2; FI2) parts of thread, every of which includes thread turns (TH1, TH2). At the same time the specified first part of thread (FE1; FI1) is closer to the specified free end (EL2; EL1), and the specified second part of thread (FE2; FI2) is closer to the central part without thread (PC2; PC1) in the part (T2; T1). Support faces (FS) and bearing faces (FL) of thread turns (TH1) in the specified first part of thread (FE1; FI1) and thread turns (TH2) in the specified second part of thread (FE2; FI2) are inclined oppositely in respect to the radial direction.
EFFECT: solution to a problem of variable axial stretching and compressing loads between two running-off threaded elements.
21 cl, 11 dwg
FIELD: oil and gas industry.
SUBSTANCE: method includes adjustment of working screw gauges of rings and working plug gauges accordingly to reference screw plug gauges and to reference screw ring gauges, at the same time the distance between the measurement plates of a reference gauge and a working gauge must be equal to l4, which is calculated according to the following formula: where l3 - distance from the measurement plane to the small end of the screw plug gauge, mm, D - inner diametre of thread of a screw ring gauge in a plane of a small end, mm, d5 - inner diametre of thread in the main plane of the screw plug gauge, mm.
EFFECT: extended service life of working gauges.
2 cl, 4 dwg
FIELD: machine building.
SUBSTANCE: screw joint elements are subjected to local elastic and elastoplastic deformations. Elastoplastic sealing element is composed of metal ring gasket (4) to be arranged between the ends of casing pipes (1, 2). Gasket is pre-cooled in refrigerator, for example, in liquid nitrogen and, then, fitted in its proper place. Pipes (1, 2) are quickly screwed off to prevent fast heating of gasket (4). Note here that said gasket (4) gets in constricted position in lengthwise axis of casing. Note here that at heating said gasket expands to fill the gap between the surfaces of its location but stays contracted like a spring since the gap between surfaces being sealed inhibit its complete expansion.
EFFECT: tightness of casing thread joints at whatever loads, longer life.
FIELD: oil-and-gas industry.
SUBSTANCE: after drilling parent hole and its anchoring to design depth, bore is expanded with cutting of casing interval of parent hole to make top and bottom parts of said parent hole. Expansion interval is cemented to drill the cement in expansion interval thereafter. Extra holes are drilled to run bearing plate which is to be oriented, fitted in place and tightly fixed by expansion so that plate side branches are located in appropriate extra holes. Bearing plate comprises two tightly connected hollow elements, one a bit longer than another one, that can expand. Note here that shorter element is composed of the first branch tor extra hole. Note also that longer element has at least one extra branch, similar to the first one. Said branches are located at different levers of longer element and are bidirectional elements.
EFFECT: possibility to construct multi-bottom wells from cased wells.
2 cl, 6 dwg
SUBSTANCE: drill pipe includes a polymer basic structure formed of bismaleimide polymer reinforced with fibres; and a hydrophobic coating including a maleimide complex and chemically connected to polymer basic structure. The coating forms a covalent link with polymer basic structure. A drill pipe erection method involves erection of the basic structure of the drill pipe from polymer material; production of hydrophobic coating; and creation of covalent chemical link between the coating and the basic structure. The coating for application onto the drill pipe is made of many layers, at least one of which is made from the material containing a chemical reagent chosen for a reaction in presence of borehole fluid media that have destructive nature in relation to polymer material.
EFFECT: providing formation of a coating on the drill pipe, which is adequately connected to the below-lying basic structure of the polymer material so that it can withstand corrosive medium present in the borehole application.
30 cl, 10 dwg
FIELD: oil and gas industry.
SUBSTANCE: connection contains mal and female elements with buttress conical trapezoidal threads and conical sealing surfaces and stop end surfaces at the ends of elements. Slope angle for bearing face of thread profile is from -4 up to +5°, slope angle of embedded face is 10-24°, taper ratio is 1:16. Tops and embedded faces of thread profile at connection screwing generate gaps in-between with width of 0.05-0.15 mm. Thread profiles of the male and female elements at the area of embedded face and top convergence is made rounded. At that radii of rounding are different for male and female elements. Stop end surfaces have angle of slope of 10-20° to normal line of the thread axial line. Slope angle of sealing surface of the male element is 13-18° to normal line of the thread axial line. Slope angle of sealing surface of the female element is 8-12°. At the female element at the area of thread tailing there is a circular groove (12) that forma cavity covering the first one and a half thread turns at the male element. At the tailing area of sealing surface and stop end surface there is a circular groove (14). The convergence area of sealing surface and stop end surface (14) of the female element and convergence area of sealing surface and tailing thread area of the male element are made rounded.
EFFECT: high leaktightness at impact of significant mechanical loads, wear resistance at multiple screwing and unscrewing and operation.
22 cl, 1 ex, 3 dwg
FIELD: oil and gas industry.
SUBSTANCE: method includes coaxial placement of inner tube with insulation, gas absorbers and centring skids in outer tube. Outer tube is equipped with fluid-tight valve that provides vacuum 10-4-10-3 mm Hg in tubular annulus. Outer and inner tubes are connected through steel linings by means of their welding to pipes by vacuum-tight seams. To outer tube linings are welded at the point of male screw placements at ends within area under the section from the first turn till base plane of thread. Thermal treatment of vacuum-tight seams provides improvement of their plasticity. Heating of inner and outer tube is made stage by stage up to final temperature of 350-450°C. At each stage of heating in tubular annulus vacuum of 10-4-10-3 mm Hg is created. Male screws are made at the ends of outer tube after mechanical treatment of vacuum-tight seams.
EFFECT: reducing heat losses at heat carrier passage through tube string, increasing operational reliability of string and efficiency of string section assembly.
2 cl, 2 dwg
FIELD: oil-and-gas industry.
SUBSTANCE: spring centraliser to be automatically locked at casing column consists of centering plates and two seamless rings. Ends of said seamless rings are jointed by weld seam. Note here that lower ring has special inclined two-six pockets (depending upon centraliser size). Said inclined pockets accommodate two forged rolls coupled by torsion spring locked by retainer in transport position. Centraliser locking in rolls displacement by the spring in wedge pocket after removal of retainer is effected by the principle of overrunning coupling. Wedge pocket is formed by centraliser ring and casing column. One roll lock centraliser against downward displacement while another one inhibits upward displacement.
EFFECT: perfected design.
FIELD: oil and gas industry.
SUBSTANCE: method for application of protective coating to inner and outer surface of pipes includes running-in of device for application of the coating into a pipe string, melting of coating and its application to pipe walls. Protective coating is applied to outer surface of couplings, up to three couplings, by means of device for application of the coating to outer surface. Protective coating is applied to outer surface of couplings is applied during running-in into pipe string. Application of protective coating to inner surface of several tubing strings is made at ground level by the device for application of the coating to inner surface. Then coating is straightened by a calibrating unit. The device for application of protective coating to inner surface of pipes includes container for melted compound, heating elements, piston and calibrating unit. The calibrating unit is flexible and there are springs inside it. Springs allows changing outer diameter of the calibrating unit when pipe diameter changes. Pressure sensors, temperature sensors, spotlights and web-cameras are installed at the device in order to control process of coating application.
EFFECT: invention allows increasing service life of downwhole equipment, increasing technological effectiveness and quality of application processes, increasing safety and reliability of the equipment.
SUBSTANCE: drill rod comprises a body connected with a nipple and a coupling and a protective jacket with an alignment ring. The body of the drill rod is made with a support collar on the outer surface. The protective jacket is made in the form of a sleeve with a hollow bottom. The jacket is connected with the alignment ring by means of thread. At the same time between the sleeve bottom and the support collar of the body there is an elastic element. The elastic element is made in the form of a cylinder from elastic material.
EFFECT: increased efficiency of drilling works, increased service life of a drilling tool and equipment.
2 cl, 1 dwg
SUBSTANCE: retaining device (13) inserted into a central channel of a drilling string component. The channel has the first diameter on at least a part of the central section of the drilling string component, and the second diameter near the ends of the drilling string component. The second diameter is less than the first diameter. The retaining device (13) comprises a lengthy body (14), forming at least partially a jacket for a transfer line. The lengthy body (14) has transverse dimensions less than the second diameter. Multiple arc elements (15) are arranged along the lengthy body (14). Arc elements are separate from the lengthy body and are attached to it.
EFFECT: arc elements are elastically bending for provision of their displacement through the second diameter and have the largest chord that is more than the first diameter in free condition for creation of an opportunity of expansion in the first diameter after stretching via the second diameter.
3 cl, 9 dwg
FIELD: oil and gas industry.
SUBSTANCE: section contains inner tube with reinforcement at the ends, centring skids, insulation and gas absorbers. Also the section contains outer tube with male screw at ends and tubing collar. Outer tube is designed with air-tight valve ensuring creation of vacuum 10-4-10-3 mm hg in annular space. In annular space there are steel linings in the form of bushings. Lining are welded to inner and outer tubes by vacuum-tight welds. To outer tube linings are welded at the point of male screw placements at ends within area under the section from the first turn till base plane of thread. In annular space linings are located so that grove in the lining and outer tube form a cavity. Centring skids are made as clamps consisting of two parts interconnected rigidly. Inner surface of centring skids is designed with friction properties.
EFFECT: reduction of heat losses during heat carrier passage through the string and increase of operational efficiency for the string.
1 cl, 3 dwg
FIELD: oil extractive industry.
SUBSTANCE: device has inner and outer pipes, placed coaxially with forming of ring-shaped space between them. Ring-shaped space is pressurized by vacuum seams, thermo-isolation is placed therein and vacuum is formed, on both sides of outer pipe thread is made, on one end thereof sleeve is screwed with isolating bushing. Vacuum seams are made at even spaces from ends of outer pipe, calculated from formula L=K·β, where L - distance between vacuum seam and end of outer pipe, mm; K - number of predicted maintenances of threads of thermo-isolated pipe; β - value of shortening of thermo-isolated pipe after single thread maintenance, mm. Also described is another variant of thermo-isolated pipe, wherein vacuum seams are made at different spaces from ends of outer pipe. Distance on side of sleeve is calculated from formula: LM=KM·β, where LM - distance between vacuum seam and end of sleeve end of outer pipe, mm, KM - number of predicted maintenances of thread of sleeve end of thermo-isolated pipe; β - value of shortening of thermo-isolated pipe after single thread maintenance, mm; and on nipple side space is calculated from formula: LH=KH·β, where LH - distance between vacuum seam and end of nipple end of outer pipe, mm; KH - amount of predicted maintenances of thread of nipple end of thermo-isolated pipe, while KM<KH.
EFFECT: higher efficiency.
2 cl, 1 dwg