RU2151262C1 - Clamp for suspension of sucker-rod string - Google Patents

Abstract

FIELD: oil-producing industry, particularly, devices used for suspension of sucker-rod strings in performance of repairs of wells equipped with sucker-rod pumps, regulation of pump stroke, etc. SUBSTANCE: clamp body has mouth for polished rod. Slider in body is installed on one side of mouth. Movable slip is engageable with rod and through wedge joint with slider. Clamp has changeable plates whose working surface is made in compliance with diameter of clamped member of sucker-rod spring. One plate is installed on front side of movable slip. The other plate is installed directly on side opposite to movable slip. Clamp is designed for self-clamping that increases its reliability and convenience in operation. Equipment of clamp with changeable plates made of plastic material provides for clamp versatility and makes it possible to avoid damage to working surface of polished rod and in this way to enhance reliability and service life of casing-head stuffing box. EFFECT: higher efficiency. 2 dwg

Description

 The invention relates to the oil and gas industry, in particular to devices used to hold the string of pump rods in weight while repairing pump wells, adjusting the stroke of the pump plunger, etc.

 Known clip (patent N 2091560), consisting of a housing with a throat under the stuffing rod. On both sides of the pharynx, dies are installed in the casing in contact with the stuffing rod on one side and with the wedge connector on rolling friction with the top of the wedge, oriented in the direction of gravity of the pump rod string. One of the dies is in a wedge pair with a slider installed in the housing with the possibility of orientation and lateral movement relative to the stuffing box (the closest analogue).

 In emergency situations, for example, with the so-called complex “pipe-rod” lift (with a paraffin string of pump rods seized by paraffin), there may be such a situation that, having turned off another pipe, we find a rod broken off over the body. With a clamp capable of catching the rod body and an elevator, one could release the stuck pump rod string by pacing and continue the difficult climb. However, the use of known clamps does not apply to sucker rods, which indicates the lack of versatility of the clamp.

 The die material must have a sufficiently high hardness to withstand contact stresses from the needle rollers. At the same time, being in contact with the stuffing box, in order to avoid damage to the polished surface, the hardness of the plate should be less than the hardness of the stuffing box with a maximum coefficient of friction between them. Such a condition can be ensured, for example, when using an opposite friction pair, providing a steel plate with an aluminum or copper replaceable lining with a coefficient of friction of 1.05 (see the appendix - photo, I.V. Kragelsky. Friction and wear.- M .: Engineering , 1968, p. 249, tab. 27). The last condition in this clamp is not met, which in some cases leads to damage to the stuffing box (see act. Production tests).

 It has been experimentally proved that for the principle of self-jamming in the clamp it is enough to have one wedge (instead of two, as in the prototype) a ram in pair on rolling friction in combination with a fixed other ram, which leads to a simplification of the design, reduction of manufacturing costs and mass of the clamp.

 The purpose of the invention is to provide versatility and improve performance characteristics of the clamp.

 The essence of the invention lies in the fact that the clamp is equipped with interchangeable linings, the working surface of which is made in accordance with the diameter of the clamping element of the string of pump rods, and the material of the interchangeable linings is selected based on the conditions of its matching unlike friction pair with the stuffing rod, one of the linings mounted on the front the side of the movable die, the other directly in the housing, on the side opposite from the movable die.

 In FIG. 1 shows a longitudinal section through a clamp along line AA, FIG. 2 is a view of the clamp along arrow B in FIG. 1.

 The clamp consists of a housing 1 with a pharynx 2 under the stuffing rod 3. On one side of the pharynx 2 in the through groove 4 of the housing 1 there is a slider 5 with a spherical bearing surface under the head 6 of the drive screw 7, which allows orientation and lateral movement of the slider 5 relative to the stuffing box rod 3. The slider 5 and the movable die 8 are associated with a wedge connector, in which the needle rollers 9 are located with the separator 10 on the couplers 11. The top of the wedge is oriented in the direction of gravity of the pump rod string. The sides 12 of the separator 10 with their projections 13 are located in the corresponding grooves of the slider 5 and the movable die 8. At the rear end of the screw 7, holes 14 are provided for an amplifier (not shown).

 The clamp is equipped with interchangeable linings 15, one of which is installed on the front side of the movable die 8, the other is directly in the housing 1 by means of a clamp 16 with a bolt 17. Over the movable 8 and the slider 5 on the housing 1 there is a casing 18, which prevents debris from entering the bearing assembly with needle rollers 9.

 The clamp for holding the column of sucker rods works as follows.

 Rotating the screw 7, the movable plate 8 is diverted from the throat. The clamp is brought to the stuffing box 3 in its predetermined area. Rotating the screw 7, the movable plate 8 is pressed against the stuffing rod 3, which must be combined with the simultaneous impact on the housing 1 with a certain downward force, thereby ensuring favorable conditions for the movable plate to occupy its upper initial position, in which the clamp is fixed on the stuffing box stock through an amplifier. Using a rocking machine, the clamp is lowered onto the pressure nut of the wellhead stuffing box (not shown), while the movable plate 8 with the lining 15, being on sliding friction with the stuffing rod, moves down on the rollers 9 of the wedge joint along the path of least resistance and the clamp wedges automatically under the self-weight of the pump rod string, the heavier the string, the greater the clamping force, and this is the main advantage of this type of clamp.

 To remove the clamp from the stuffing box 3, it is necessary to take it upward from the pressure nut of the wellhead stuffing box by means of a rocking machine, use the amplifier to loosen screw 7, and then, unscrewing the screw 7 manually, remove the movable plate 8 from the throat 2 and remove the clamp from the stuffing box 3 .

 When, in the process of self-jamming, the movable plate 8, together with the replaceable liner 15 and the stuffing rod, moves down along the wedge connector, then the stuffing rod on the opposite side slides along the replaceable stationary liner 15, bringing the latter to the state of plastic deformation, as a result of which the most complete its interfacing with the gland rod, which (conjugation) is initially almost impossible to provide. At the same time, some microlayer is simultaneously carried off by the stuffing rod from the working surface of the fixed removable lining 15, forming a new clean metal surface on it, which subsequently creates favorable conditions for better engagement with the stuffing rod at a friction coefficient of unlike pairs - 1.05 ("aluminum - steel "or" copper-steel ", p. 294, tab. 27, IV Kragelsky. Friction and wear. - M.: Mechanical Engineering, 1968).

 Thus, for each clamping cycle, the fixed interchangeable lining 15 will experience some wear, ensuring the preservation of the polished surface of the stuffing box 3 and improving the engagement conditions with it. A set of interchangeable pads 15 allows you to expand the scope and simplify the design of the clamp by eliminating the second wedge pair of dies on rolling friction.

 The laid down principle of operation of the clamp, designed for self-jamming, increases its reliability, creates ease of maintenance in combination with efficiency. The clamp equipped with interchangeable linings made of plastic material corresponding to the opposite pair of friction with the stuffing box, together, ensures its versatility and avoids damage to the working surface of the stuffing box, which increases the reliability and service life of the wellhead stuffing box, which depends on the environment.

Claims (1)

 A clamp for holding a string of pump rods, comprising a housing with a throat for a stuffing rod, configured to interact with an stuffing rod with a clamp on both sides of the pharynx, a slider installed in the housing on one side of the pharynx with the possibility of orientation and lateral movement relative to the stuffing box , a movable die located in the housing with the possibility of contacting the front side with the stuffing rod, and the back side with the slider through the wedge connector on rolling friction with the top of the wedge, about oriented in the direction of gravity of the column of sucker rods, characterized in that the clamp is equipped with interchangeable linings, the working surface of which is made in accordance with the diameter of the clamped element of the string of sucker rods, and the material of the interchangeable linings is selected based on the conditions of its matching unlike friction pair with the stuffing rod, one of the pads is installed on the front side of the movable die, the other in the housing, on the side opposite from the movable die.

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