RU2679627C1 - Thread on pipes at the wellhead cutting device - Google Patents

Abstract

FIELD: technological processes.SUBSTANCE: invention relates to the thread on pipes at the wellhead cutting device. Device consists of a housing, a cutting tool holder, the cutting tool rotation and feeding mechanisms mounted on the centering cage with the actuator installed thereon, and equipped with replaceable setting screws, which ensure the threads cutting device installation on pipes of different diameters, rotation of the housing around the pipe axis on the centering cage is carried out by means of the planetary gear train along the guides in rolling bearings, at that ensuring the automatic, without using of a special copier, the cutting head movement in the longitudinal and transverse directions with respect to the pipe axis with performance, by means of replaceable cutting tool, of the pipe head cutting operations, facing and the lead-in chamfer formation thereon, its longitudinal turning into a cone and the threads cutting due to included into the device replaceable sets of gears and helical gears, installed on the rotating body without disassembling, which gear ratios and threaded pairs pitches are selected by carrying out of the appropriate calculations method that ensure the cut threads parameters fulfillment with the appointment at that of the cutting technological modes standard values and the proper quality of performance.EFFECT: use of the proposed device allows the device installation on the well casing head without the lifting mechanisms usage, increased its service life by reduction of the rotating parts rubbing surfaces resistance, the cutting tool movement in the transverse and longitudinal directions during the pipe end cutting, its facing with the lead-in chamfer execution, as well as the cone turning and the thread cutting were performed without using of a special copier in compliance with the feeds values, corresponding to the recommended for steel products turning standard values, at that, the device operation reconfiguration from cutting of the triangular thread profile to trapezoidal, and vice versa, is possible without its disassembling.1 cl, 3 dwg

Description

The invention relates to the oil and gas exploration and exploration industries and is intended for threading triangular and trapezoidal profiles of casing pipes according to GOST 632-80 directly at the wellhead.

A device for cutting threads on pipes at the wellhead (1), consisting of a table, hydraulic drive, tool holder, rotation mechanism and supply of a cutting tool, including a unit for converting rotational motion into rotational-translational, a copier, slide and centering holder with two cylindrical belts, supporting collar with a centering belt equipped with four internal interchangeable set screws for threading on pipes of various diameters, and four external elongated adjustments ovochnymi screws with prismatic abutments with crosswise corrugation on the working surface.

However, the known device has the following disadvantages:

- the desire to carry out undivided installation of the device on the casing head made the design of the device as a whole heavier, which led to the need to mount the device on the casing using a mounting plate specially designed for this purpose with the mandatory use of a lifting device;

- the rotation of the screw around the axis of the casing is carried out on the cylindrical surface of the centering cage, as a result of sliding friction leads to increased wear of the contacting surfaces, reducing the life of the device before repair;

- transverse feed of the cutting head with a cutting tool is carried out along the slide guides in the form of a dovetail, which requires constant monitoring and adjustment of the required clearances;

- the formation of the cone, when turning and threading on the head of the pipe, is carried out by covering the rotating rollers mounted on the table and rolling them around the copier inclined to the longitudinal axis of the pipe, the manufacture of which, in compliance with the required taper of the thread (1 ° 47'24``), is conjugated with difficulties in ensuring high accuracy of its execution, while there is no possibility, independent of the copier, of perpendicular movement of the cutting head for transverse feeding, excluding longitudinal, with end the pipe end with the subsequent formation of a lead-in chamfer, which are of no small importance for designing high-quality threads, as well as performing, if necessary, the operation of cutting the pipe end;

- the longitudinal feed of the cutting tool during turning is carried out by a value equal to the thread pitch of the device’s screw pair (3.175 or 5.08 mm) installed on the pipe, several times higher than the recommended values of the longitudinal feeds of the cutting tool when turning steel products (2, p. 72, 73 ), which negatively affects the quality of the formation of the conical surface, prepared for threading;

- for cutting various threads (triangular with a step of 3.175 mm and trapezoidal with a step of 5.08 mm), the device is equipped with two sets of screw pairs with corresponding thread steps, the overall dimensions of the components of which increase the cost of production during their manufacture and the mass of the product as a whole, and their replacement , when switching from one type of cut thread to another, it is impossible without a complete disassembly of the device, which requires significant labor costs.

The aim of the invention is to obtain a technical result in which it is possible to mount the device on the head of the casing of the well without the use of lifting mechanisms, increase its service life by reducing the resistance of the friction surfaces of rotating parts, moving the cutting tool in the transverse and longitudinal directions when cutting the end of the pipe, its milling with the execution of the chamfer, as well as turning the cone and threading were carried out without using a special copier in compliance with innings rank corresponding standard values recommended for turning of steel products, wherein the reconfiguration of the device with a triangular cutting thread to trapezoidal, and vice versa, is possible without disassembly.

The specified technical result is achieved by the fact that in the device for cutting threads on pipes at the wellhead, consisting of a body, a tool holder, rotation mechanisms and feeds of the cutting tool mounted on a centering sleeve with a drive installed on it and equipped with interchangeable set screws to ensure installation of the device for threading on pipes of various diameters, the rotation of the housing around the axis of the pipe on the centering holder is carried out by a planetary gear transmission along the guides in the base rolling bearings, providing, at the same time, automatic, without the use of a special copier, moving the cutting head in the longitudinal and transverse directions relative to the axis of the pipe, by means of a replaceable cutting tool, cutting the pipe head, trimming and forming on it a chamfer, longitudinal its turning on the cone and threading due to the device as part of the device, and installed on a rotating case without disassembling it, replaceable sets of gear and screw gears, transmission relations and steps of threaded pairs of which are selected by the method of carrying out appropriate calculations, ensuring the performance of the parameters of the threaded threads with the purpose, moreover, of the normative values of the values of the technological cutting conditions and the proper quality of performance.

The design of the device is illustrated by drawings, where in FIG. 1 shows a general view of the device; in FIG. 2 - a support; in FIG. 3 - screw with slotted nut

The device consists of the following main components and parts (Fig. 1):

A centering sleeve 1 is mounted on the casing head with a gear wheel Z1 arranged on it, in the lower and upper parts of which there are clamping crackers 2 and thrust screws 3 equally spaced around the circumference. Drive D is fixed to the holder 1 (hydraulic, pneumatic or electric motors may be used ) onto which the drive gear Z2 is mounted. Housing 6 is mounted on the outer diameter of the cage 1 on bearings 4 and 5. Clearance in the bearings 4 and 5 is adjusted with nuts 7 and 8. A gear wheel Z3 is located on the lower part of the housing 6.

In the housing 6 there are bushings 9 and 10, between which a gear Z4 is installed on the bearings 11 and 12, which is meshed with the gear Z1. The inner hole of the gear Z4 is slotted, into which the slotted nut 13 is inserted with the threaded rod 14 screwed into it, forming a screw pair VP1 with each other. The rod 14 is fixed against rotation by a movable key (slotted) connection with a guide 15 fixed in the sleeve 9. To prevent axial movement of the spline nut 13, a sleeve 16 is inserted into the sleeve 10, held by a union nut 17, fixed by a screw 18. To the upper part of the rod 14, made in the form of a flange, by means of bolts 19, a support 20 is fastened, the vertical movement of which, together with the rod 14, can be eliminated by installing on the union nut 17 of the straps 21 with their fastening with bolts 22. A gear ring is mounted on the housing 6 ka 23 with teeth Z5.

In the support 20 there is a bore (Fig. 2), in which a nut 26 with a gear Z6, which is meshed with the teeth Z5 of the rack 23, is installed on the bearings 24 and 25. A threaded sleeve 27 is screwed into the nut 26, forming a VP2 screw gear with nut 26. In the threaded sleeve 27 there is an opening with a keyway, which includes a mandrel 28 with a key 29, which together with the groove in the threaded sleeve 27 forms a movable keyed connection. The cutting tool 30 is fixed in the mandrel 28. The mandrel 28 has a groove in which a screw 31 enters, fixing the mandrel 28 against rotation and not preventing its axial movement.

At the end of the threaded sleeve 27 is a feed mechanism with a screw 32 and a limb 33.

The device is equipped (Fig. 3) with three marked (No. 1, No. 2 and No. 3) sets of locknuts 13, screwed with threaded rods 14, with different thread steps D, used for cutting triangular (No. 1), or trapezoidal (No. 2) profiles accordingly. To perform the operations of cutting the head of the pipe, its facing and shaping the lead-in chamfer, followed by turning the cone, set No. 3 is used, and for cutting, trimming and chamfering, only the rod 14 without nut 13 is used, and when turning the cone, the complete assembly.

The principle of operation of the device is as follows (Fig. 1).

The motor D included in the operation, rotating the gear Z4, moves, depending on the direction of rotation of the shaft, the caliper up or down by means of screw transmission VP1. The gear Z6, being in constant engagement with the gear rack Z5, rotates the threaded sleeve 27. When the caliper moves down, the mandrel 28 with the cutter 30 moves in the radial direction from the axis, and when moving upwards - to the axis of the casing, thereby forming, with lateral feed cutter, conical surface. The depth of cut at each vertical passage of the cutter is set using the feed mechanism by rotating the screw 32 with a control on the dial 27.

The procedure for processing the head of the casing.

Using clamping crackers 2 and thrust screws 3, the device is mounted and centered on the casing with the necessary distance H from the end of the pipe.

To perform cutting or trimming operations of the pipe head with the formation of a lead-in chamfer on it:

- the support 20 is joined with the rod 14 of the set No. 3 without the nut 13;

- the sleeve 16 is inserted into the sleeve 10, passing into the union nut 17, screwed onto the sleeve 10;

- on the union nut 17 is fixed with bolts 22 of the strap 21;

- a cutting tool 30 is installed in the caliper mandrel 28, intended (for cutting, if necessary, the end of the pipe — detachable), for trimming the tip of the pipe and forming a lead-in bevel on it;

- turn on the drive D, which through the gear Z2-Z3 drives the housing 6, which is the carrier in the planetary gear Z1-Z4.

Vertical movement of the caliper does not occur due to the lack of a slotted nut 13 in the caliper assembly. The lateral feed of the cutter is carried out manually by partially turning the caliper limb 33 at low revolutions of the table around the pipe. After the operation is completed, the cutter, turning off the drive, is taken to its original position.

Next, for turning the cone:

- from the union nut 17 remove the straps 21;

- unscrew the nut 17 and remove the caliper from the sleeve 10 along with the sleeve 16;

- a slotted nut 13 is screwed onto the rod 14 and, together with the sleeve 16, is inserted into the sleeve 10, aligning the splines of the nut 13 and gear Z4;

- on the sleeve 10, wrap the union nut 17 and fix it with a bolt 18, providing free, without gaps, rotation of the spline nut;

- a cutting tool 30 (a through-cutter) is installed in the caliper mandrel 28;

- alternately switching the direction of rotation of the drive shaft of the engine produce turning the conical surface.

Next, for threading:

- unscrew the nut 17 and remove the caliper from the sleeve 10 along with the sleeve 16;

- disconnecting the rod 14 with the caliper 20, change the set No. 3 to set No. 1, or No. 2, depending on what type of thread you want to cut on the column;

- the assembled caliper is inserted into the sleeve 10 together with the sleeve 16, aligning the splines of the nut 13 with the splines of the gear Z4;

- a sleeve nut 17 is screwed onto the sleeve 10 and fixed with a screw 18, providing free, without gaps, rotation of the nut 13;

- a threaded cutter is mounted in the caliper mandrel 28, forming a corresponding thread profile during vertical movement of the caliper.

The gear ratio of the planetary gear Z1-Z4, the steps of screw gears VP1 (in sets No. 1, No. 2, No. 3) and VP2 are selected as a result of appropriate calculations with the condition of ensuring the required parameters (taper and pitch) of the thread being cut, as well as the standard values of longitudinal feeds when grinding a conical surface.

Information sources

1. "Device for threading pipes on the wellhead", patent for the invention No. 2474671, 2012

2. V.N. Feshchenko P.X. Makhmutov, Turning, Higher School, Moscow 2005.

Claims (1)

A device for cutting threads on pipes at the wellhead, consisting of a housing, a tool holder, rotation mechanisms and feeds of the cutting tool mounted on a centering sleeve with a drive installed on it and equipped with interchangeable set screws to ensure installation of the thread cutting device on pipes of various diameters, rotation housing around the axis of the pipe on the centering cage is carried out by a planetary gear transmission along the guides in the rolling bearings, while ensuring automatic, b without the use of a special copier, moving the cutter head in the longitudinal and transverse directions with respect to the pipe axis with the help of a replaceable cutting tool, cutting the pipe head, trimming and forming a lead-in bevel on it, its longitudinal turning to the cone and threading due to the available as a part of the device and installed on a rotating case without disassembling interchangeable sets of gear and screw gears, the gear ratios and steps of the threaded pairs of which are selected by the method ohm carrying out the relevant calculations, ensuring the performance of the parameters of the threaded threads with the appointment of the normative values of the values of the technological cutting conditions and the proper quality of performance.

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