RU2449171C2 - Pumping unit - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: pumping unit comprises a frame 1, a beam 3 installed on a stand 2 with a counterbalance 4 and a head 5, and also a drive 7 to convert rotation of an engine into reciprocal motion made in the form of a screw-rolling nut pair. The drive 7 is connected by a hinged joint 9 with the beam 3 and a reversive electric motor 8 connected by a hinged joint 10 with the frame 1.

EFFECT: higher reliability of pumping unit operation with the possibility of operation at low temperatures.

5 cl, 5 dwg

Description

The invention relates to surface devices for driving deep pumps and can be used to drive sucker rod pumps in oil wells.

Known installed at the wellhead rocking machine containing lower and upper beams. At least two ball-screw drives are installed between the beams, the nuts of which are connected by a traverse. A polished rod is fixed on the traverse. The screw of one of the drives is connected to the reversing motor and, through a chain transmission, to another screw. Reversing the direction of rotation of the motor provides reciprocating movement of the traverse [US patent No. 5404767].

The rocking machine has the following disadvantages:

- the drive in rotation from the engine is carried out on one of the screws, and on the other the rotation is transmitted using a chain drive, therefore, screw-nut pairs are in unequal conditions due to significant backlash of the chain drive, which can lead to distortion of the crosshead;

- the weight of the rod string is not balanced, which leads to an increase in electric motor power and excessive consumption of electricity.

The closest technical solution (prototype) is a rocking machine containing a balancer mounted on a rack with a counterweight and a head with suspension for attaching a polished rod. The reciprocating movement of the balancer is carried out by means of a hydraulic piston-cylinder type mounted next to the counterweight. The piston rod and the cylinder body of the hydraulic actuator are pivotally connected to the balancer and the frame of the rocking machine, respectively. The hydraulic drive of the pumping unit is carried out by applying pressure from a hydraulic pump driven by an electric motor [UK patent No. 1222422].

The disadvantage of the rocking machine is the significant complexity of the hydraulic drive, which leads to a decrease in the reliability of the rocking machine. In addition, the viscosity of the hydraulic fluid at low temperatures increases significantly. This leads to an increase in hydraulic resistance, power consumption and the possibility of failure of the motor.

The objective of the invention is to increase the reliability of the rocking machine with the ability to work at low temperatures.

To solve this problem in a known rocking machine containing a frame, a rack, a balancer with a counterweight and a head, as well as a drive for converting the rotation of the engine into reciprocating motion installed in the housing and articulated with the balancer, the drive is made in the form of a pair of screws is a rolling nut and is connected to a reversible electric motor articulated with a frame, the drive element articulated with a balancer being in movable connection with the housing and its stroke limited by at least one sensor m displacement and dampers, and the rotating element is connected to the motor shaft; the drive nut, which is in a movable connection with the housing, moves the balancer by means of a hollow rod enclosing the screw, the upper end of the screw being installed in the bearing connected to the housing by means of brackets passing through the slots in the hollow rod, and the drive screw is connected to the shaft of the reversible electric motor; the hollow stem is in the corrugated sleeve and articulated with the balancer, and the body contains an elastic shell, the outer surface of which communicates with the atmosphere; the hollow rod is connected to a sealed casing, articulated with a balancer and included in a movable connection with the housing; the drive screw, which is in a movable connection with the housing, moves the balancer by means of a sealed rod located in the corrugated sleeve, and the drive nut is connected to the shaft of the reversible electric motor by means of a pipe enclosing the screw and is mounted in a bearing connected to the housing.

These signs can eliminate the disadvantages inherent in the prototype, through the use of a screw-nut rolling drive type, which provides direct conversion of rotation into reciprocating motion without the use of an intermediate high-pressure oil pump and hydraulic system.

Figure 1 schematically shows the design of the rocking machine. Figure 2 and 3 schematically shows the various designs of one embodiment of the drive, figure 4 - the mounting unit of the upper bearing of the screw, and figure 5 is another embodiment of the drive.

The rocking machine contains a frame 1, a rack 2 mounted on it with a balancer 3 and a counterweight 4. The head 5 of the balancer 3 is connected by cables to the suspension 6 for attaching a polished rod. The screw-nut type 7 drive is used to convert the rotation of the reversible electric motor 8 into the reciprocating motion of the balancer 3. The drive 7 and the reversible electric motor 8 are connected to the balancer 3 and the frame 1 using hinges 9 and 10, respectively.

The nut 11 (figure 2) is in a movable connection with the housing 12 of the actuator 7 by means of a key connection 13 and is connected to the hollow rod 14, covering the screw 15, connected to the shaft 16 of the reversible electric motor 8. The ends of the screw 15 are installed in the bearings 17 and 18. The upper the bearing 18 is connected to the housing 12 by means of brackets 19 passing through the slots 20 in the hollow stem 14 (Fig. 4), providing a fixed-fixed method of mounting the drive. The internal cavity of the housing 12 is sealed from below by an annular seal 21.

To ensure reverse motor 8 in the upper and lower parts of the housing 12 installed sensors 22 and 23 of the displacement, connected to the engine control station (not shown). The distance between the sensors 22, 23 corresponds to the stroke length of the rocking machine. The stopping smoothness at the upper and lower points of movement of the rocking machine is provided by the control station for the specified rotation mode of the electric motor 8, as well as dampers 24 and 25. Only one displacement sensor 21 or 22 can also be installed, and the stroke length can be counted by the number of revolutions of the reversing electric motor 8 .

The stroke length of the rocking machine is constant, and the performance of the rocking machine with a given diameter of the pump is smoothly controlled by the number of revolutions of the electric motor 8 and the corresponding number of swings. If necessary, the stroke length can also be adjusted by counting the speed of the engine 8 relative to one of the sensors 21 or 22.

The hollow stem 14 is protected by a corrugated sleeve 26, and the housing 12 contains an elastic sheath 27, the outer surface of which communicates with the atmosphere. The hollow rod 14 can be covered by a cylindrical casing 28 (Fig. 3), sealed by an annular seal 29. The casing 28 is movably connected to the housing 12 of the actuator 7 by means of a key connection 30. To prevent dust from entering the cavity of the casing 27, a filter 31 is installed.

In another embodiment of the actuator (Fig. 5), the screw 15 is in a movable keyed connection 32 with the housing 12 and moves the balancer 3 by means of a rod 33, protected by a corrugated sleeve 34 and provided with a seal 35. The nut 11 of the actuator is connected to the shaft 16 of the reversible electric motor 8 by means of a pipe 36, enclosing the screw 15, and installed in the bearing 37 connected to the housing 12. The screw 15 contains bearings 38 in contact with the pipe 36.

Rocking machine works as follows.

When the shaft 16 of the reversible electric motor 8 is rotated, the screw 15 of the actuator 7, rotating in the bearings 17 and 18, transmits the torque to the nut 11. The nut 11, which is in the movable key connection 13 with the housing 12, together with the hollow rod 14 reciprocates, moreover, the rod 14 is moved relative to the brackets 19 passing through the slots 20. The hollow rod 14 by means of a hinge 9 transmits a reciprocating motion mounted on the rack 2, the balancer 3 with the counterweight 4, as well as the head 5 and the suspension 6 of the polished rod yes sucker rod pump. In this case, the reversing motor 8 swings in the hinge 10 relative to the frame 1, and the actuator 7 moves together with the balancer 3 using the hinge 9. When the nut 11 approaches the upper or lower points, the displacement sensor 22 or 23 gives a signal to the reversing electric motor 8, which smoothly slows down rotation when interacting with the damper 24 or 25 to a complete stop and subsequent reverse.

When moving the hollow rod 14, insulated by a corrugated sleeve 26, there is a change in the volume of the housing 12, insulated from below by a seal 21, which is compensated by an elastic shell 27.

When moving the hollow rod 14 and the cylindrical casing 28 connected to it (FIG. 3), sealed by an annular seal 29, which is movably connected to the housing 12 by means of a key connection 30, the volume of the actuator 7 changes significantly, and air passes into the cavities through the filter 31 , preventing dust from entering the body cavity 12.

In another embodiment of the drive (FIG. 5), the motor 8 rotates a nozzle 36 enclosing a screw 15, which cooperate by means of a bearing 38. The nozzle 36 transmits a torque to a nut 11 that rotates in the bearing 37. The screw 15, which is in key connection 32 with the housing 12, moves the sealed 35 rod 33, which is protected from the environment by the corrugated sleeve 34. When reversing the direction of rotation of the electric motor 8, the screw 15 together with the rod 33 performs a reciprocating movement transmitted to the balancer 3 pos by means of the hinge 9. Otherwise, the drive works similarly to that shown in FIGS. 2 and 3.

As a rolling screw-nut drive, a ball or roller screw drive can be used.

Claims (5)

1. A rocking machine containing a frame, a rack, a balancer with a counterweight and a head, as well as a drive for converting the rotation of the engine into a reciprocating motion installed in the housing and articulated with a balancer, characterized in that the drive is made in the form of a pair of screw- a rolling nut and connected to a reversible electric motor pivotally articulated with the frame, the drive element pivotally articulated with the balancer is in movable connection with the housing and its stroke is limited by at least one displacement sensor and empferami, and a rotating member coupled to the motor shaft. 2. The rocking machine according to claim 1, characterized in that the drive nut, which is in a movable connection with the housing, moves the balancer by means of a hollow rod enclosing the screw, the upper end of the screw being mounted in a bearing connected to the housing using brackets passing through slots in the hollow stem, and the drive screw is connected to the shaft of the reversible electric motor. 3. The rocking machine according to claim 2, characterized in that the hollow rod is located in the corrugated sleeve and articulated with the balancer, and the body contains an elastic shell, the outer surface of which communicates with the atmosphere. 4. The rocking machine according to claim 2, characterized in that the hollow rod is connected to a sealed casing, articulated with a balancer and included in a movable connection with the housing. 5. The rocking machine according to claim 1, characterized in that the drive screw, which is in movable connection with the housing, moves the balancer by means of a sealed rod located in the corrugated sleeve, and the drive nut is connected to the shaft of the reversible electric motor by means of a pipe covering the screw, and mounted in a bearing connected to the housing.

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