Wellhead polish rod controllable sealing device

Abstract

The utility model relates to a controllable sealing device for a wellhead polish rod, which comprises a dustproof cover, a grease cavity, a sealing cavity, a connecting hoop and a hydraulic compensation system, the upper end of the sealing cavity is in threaded connection with the grease cavity, the dustproof cover is sealed at the upper end of the grease cavity, the sealing cavity is in threaded connection with the connecting hoop, and a packing and a pressing sleeve are placed in the sealing cavity; the pressing sleeve, the packing and the sponge in the oil cavity are all tightly attached to the outer wall of the polish rod. Two rectangular holes are symmetrically formed in the wall of the sealing cavity, two threaded holes are symmetrically formed in the middle of the pressing sleeve, an upper corner seat is fastened in each threaded hole, the upper corner seats are in sliding connection with the rectangular holes, a sealing groove is formed in the upper end of the pressing sleeve, lower corner seats are symmetrically arranged in the connecting hoop, and a hydraulic cylinder is connected between each pair of the upper corner seat and the lower corner seat. A hydraulic cylinder piston rod is in bolted connection with the upper angle seat; a hydraulic cylinder oil cylinder base is in bolted connection with the lower angle seat; the hydraulic compensation system comprises the two hydraulic cylinders. According to the sealing device, the packing is always tightly attached to the polish rod, and the purpose of controllable sealing is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of a wellhead polished rod sealing device for an oil pumping unit, in particular to a wellhead polished rod controllable sealing device. Background Art

[0002] The main principle of the wellhead bare rod seal of the pumping unit is to use the pressure of the gland to give the packing. The packing expands radially under the action of pressure, and the inner wall of the packing and the bare rod are squeezed axially, so that the entire annulus area is filled, and the purpose of packing box sealing is achieved. In the production process, due to excessive wear caused by frequent friction between the bare rod and the packing, aging of the packing, etc., the seal of the wellhead bare rod is not tight, and crude oil leakage eventually occurs. Therefore, in order to ensure a good sealing effect, it is necessary to continuously tighten the packing, but squeezing too loose will not have a sealing effect, and too tight will lead to increased energy consumption of the pumping unit and increase crude oil costs. Therefore, it is necessary to develop a controllable sealing device for the wellhead bare rod of the pumping unit. Summary of the invention

[0003] The utility model aims to provide a wellhead polished rod controllable sealing device, which is used to solve the problem of loose sealing and crude oil leakage during the production process of the wellhead polished rod sealing device of the prior art.

[0004] The utility model adopts the following technical scheme to solve the technical problems: the controllable sealing device of the wellhead polished rod comprises a dust cover, a grease chamber, a sealing chamber, a connecting clamp and a hydraulic compensation system; the upper end of the sealing chamber is threadedly connected with the grease chamber, the dust cover is closed at the upper end of the grease chamber, the sealing chamber is threadedly connected with the connecting clamp, a packing and a pressing sleeve are placed in the sealing chamber, and the pressing sleeve is pressed on the packing; the polished rod enters the sealing chamber from the dust cover and passes through the connecting clamp, and the pressing sleeve, the packing and the sponge in the grease chamber are all tightly fitted with the outer wall of the polished rod; two rectangular holes are symmetrically arranged on the sealing chamber wall, two threaded holes are symmetrically arranged in the middle of the pressing sleeve, an upper angle seat is fastened in each threaded hole, and the upper angle seats are all slidably connected with the rectangular holes, a sealing groove is arranged on the upper end of the pressing sleeve, and lower angle seats are symmetrically arranged in the connecting clamp, a hydraulic cylinder is connected between each pair of upper angle seats and lower angle seats, the piston rod of the hydraulic cylinder is bolted to the upper angle seat, and the oil cylinder base of the hydraulic cylinder is bolted to the lower angle seat; the hydraulic compensation system comprises the two hydraulic cylinders.

[0005] In the above scheme, the hydraulic compensation system also includes an accumulator, a three-position four-way reversing valve, a first one-way valve, and a second one-way valve. The A port of each hydraulic cylinder is connected to the three-position four-way reversing valve through a pipeline, and the B port of each hydraulic cylinder is connected to the three-position four-way reversing valve through a pipeline. The three-position four-way reversing valve is respectively connected to the first one-way valve and the second one-way valve through corresponding pipelines. An accumulator is installed on the pipeline between the first one-way valve and the three-position four-way reversing valve, and the accumulator is provided with a pressure gauge.

[0006] In the above scheme, a center hole is set in the dust cover, and the polished rod passes through the center hole to enter the sealing cavity. The dust cover is threadedly connected to the upper end of the grease cavity, and the lower end of the dust cover presses the rubber sealing ring on the inner baffle of the grease cavity, and the inner wall of the rubber sealing ring fits tightly with the outer wall of the polished rod.

[0007] In the above scheme, an external thread is arranged at the lower end of the butter cavity, a stepped end face is arranged in the butter cavity, the sponge and the baffle are respectively placed on the corresponding end faces in the butter cavity, and the sponge in the butter cavity is soaked with butter and fits with the polished rod.

[0008] In the above scheme, an internal thread is arranged at the upper end of the sealing chamber, the lower end of the butter chamber is threadedly connected to the upper end of the sealing chamber, an external thread is arranged at the lower end of the sealing chamber, the lower end of the sealing chamber is threadedly connected to the connecting clamp, the connecting clamp is connected to the wellhead clamp, and two symmetrical threaded holes are arranged on the outer wall of the connecting clamp, and a lower angle seat is fastened in each threaded hole.

[0009] In the above scheme, a sealing groove is arranged at the upper end of the pressing sleeve, an O-type rubber sealing ring is arranged at the sealing groove, and the upper end of the pressing sleeve and the sealing cavity are sealed by the O-type sealing ring.

[0010] In the above scheme, each pair of upper and lower corner seats coincides with the center plane of the hydraulic cylinder.

[0011] The utility model has the following beneficial effects:

[0012] The utility model has a simple structure. The compression sleeve presses the packing added to the oil well to ensure that the oil well polished rod and the packing are in a sealed state. Under the action of the hydraulic cylinder, a downward force is always applied to the sealing packing. As the packing is continuously worn, when the packing becomes loose, the accumulator can provide energy supplement to the hydraulic cylinder in time, and the hydraulic cylinder contracts in time, thereby continuing to compress the packing to ensure that the oil well packing and the polished rod are always in a sealed state.

[0013] The utility model discloses a sealing cover which presses a baffle gasket and a rubber sealing ring in a grease cavity, and uses a dust cover to press the rubber sealing ring to prevent external dust from entering the equipment; the sealing cavity is threadedly connected to a connecting clamp; the design is based on the original wellhead structure, and the device is connected to the original wellhead by a buckle, which is convenient for installation and maintenance.

[0014] 3. The utility model utilizes the accumulator to replenish energy to the hydraulic rod in time, so that the hydraulic cylinder can be extended and retracted in time to change the position of the compression sleeve, so that the packing can expand radially and always fit closely with the polished rod, thereby achieving the purpose of controllable sealing.

[0015] 4. The sponge in the inner circle of the butter cavity of the utility model is soaked with grease to evenly apply a layer of oil film on the surface of the polished rod, so that the whole device maintains good lubrication during the relative sliding with the polished rod, and the oil film can also play a certain sealing role. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the utility model.

[0017] Figure 2 It is a structural schematic diagram of the sealing chamber in the utility model.

[0018] Figure 3 It is a structural schematic diagram of the medium-pressure sleeve of the utility model.

[0019] Figure 4 It is a schematic structural diagram of the dust cover and the butter cavity of the utility model.

[0020] Figure 5 It is a schematic structural diagram of a second embodiment of the utility model.

[0021] Figure 6 This is the principle diagram of the hydraulic compensation system in the utility model.

[0022] In the figure: 1- bare rod, 2- dust cover, 3- rubber sealing ring, 4- stopper, 5- sponge, 6- butter cavity, 7- pressing sleeve, 8- packing, 9- support seat, 10- sealing cavity, 11- connecting clamp, 12- lower angle seat, 13- hydraulic cylinder, 14- rectangular hole, 15- upper angle seat, 16- O-type sealing ring, 17- internal thread, 18- external thread, 19- threaded hole, 20- sealing groove, 21- three-position four-way valve, 22- accumulator, 23- pressure gauge, 24- first one-way valve, 25- second one-way valve. DETAILED DESCRIPTION

[0023] The utility model is further described below in conjunction with the accompanying drawings:

[0024] Combination Figure 1-Figure 4As shown, this wellhead polished rod controllable sealing device includes a dust cover 2, a butter chamber 6, a sealing chamber 10, a connecting clamp 11, and a hydraulic compensation system. The upper end of the sealing chamber 10 is threadedly connected to the butter chamber 6. The dust cover 2 is closed at the upper end of the butter chamber 6. The inner wall of the butter chamber 6 is stepped. The sponge 5 and the stopper 4 are placed on the stepped surface. The rubber sealing ring is placed on the stopper 4. The minimum diameter of the inner wall of the butter chamber 6 is greater than the diameter of the polished rod 1. The dust cover 2 is threadedly connected to the butter chamber 6, so that the rubber sealing ring 3 is squeezed. The sponge soaked in grease in the inner circle of the butter chamber is evenly coated with a layer of oil film on the surface of the polished rod, so that the entire device maintains good lubrication in the relative sliding with the polished rod. At the same time, the oil film can also play a certain sealing role. The sealing chamber is threadedly connected to the connecting clamp. Packing and a compression sleeve are placed in the sealing chamber. The compression sleeve is pressed on the packing. The packing is placed on the support seat 9. The inner diameter of the support seat 9 is greater than the outer diameter of the polished rod 1 and smaller than the inner diameter of the lower opening of the sealing chamber 10. The pressing sleeve 7 is provided with a sealing groove 20, and the upper end of the rectangular hole is sealed by an O-type rubber sealing ring; the light rod enters the sealing cavity from the dust cover and passes through the connecting clamp, and the pressing sleeve 7, the packing 8 and the sponge in the butter cavity are tightly fitted with the outer wall of the light rod; two rectangular holes 14 are symmetrically arranged on the sealing cavity wall, and two threaded holes 19 are symmetrically arranged in the middle of the pressing sleeve 7, and an upper angle seat 15 is fastened in each threaded hole. The upper angle seats 15 are all slidably connected with the corresponding rectangular hole 14, and the length of the pressing sleeve 7 is greater than the length of the symmetrical rectangular hole 14. The sealing groove 20 is provided on the upper end of the pressing sleeve 7, and the lower angle seats 12 are symmetrically arranged in the connecting clamp 11. A hydraulic cylinder 13 is connected between each pair of upper angle seats 15 and lower angle seats 12, and the hydraulic cylinder piston rod is bolted to the upper angle seat 15, and the hydraulic cylinder oil cylinder base is bolted to the lower angle seat 12; the pressing sleeve 7 and the upper angle seat 15 move up and down in the rectangular hole 14 as the hydraulic cylinder 13 expands and contracts. The hydraulic compensation system includes the two hydraulic cylinders, the lower part of which is hinged to the lower angle seat welded on the connecting clamp, and the upper part is hinged to the upper angle seat. The hydraulic cylinders are telescoped to change the position of the compression sleeve, so that the packing 8 expands radially and always fits tightly with the polished rod, thereby achieving the purpose of controllable sealing.

[0025] The second implementation mode of the utility model is combined with Figure 1-Figure 6As shown, the controllable sealing device for the polished rod at the wellhead includes a dust cover 2, a butter cavity 6, a sealing cavity 10, a connecting clamp 11, and a hydraulic compensation system. The central aperture of the dust cover 2 is slightly larger than the diameter of the polished rod. The lower end of the dust cover 2 is pressed tightly against a rubber sealing ring 3 on a stopper 4 in the butter cavity 6. The inner wall of the rubber sealing ring 3 is tightly fitted with the outer wall of the polished rod 1. The outer wall of the lower end of the butter cavity 6 is provided with an external thread. The butter cavity 6 is provided with a stepped end surface. The sponge 5 and the stopper 4 are respectively placed on the corresponding end surfaces in the butter cavity 6. The inner wall of the sponge 5 is tightly fitted with the outer wall of the polished rod 1, the maximum inner diameter of the baffle 4 is smaller than the outer diameter of the polished rod, the inner wall of the upper end of the sealing cavity 10 is provided with an internal thread 17 which is threadedly connected to the butter cavity 6, the lower end of the sealing cavity 10 is provided with an external thread 18 which is threadedly connected to the inner wall of the connecting clamp 11, the connecting clamp 11 is connected to the wellhead clamp, the outer wall of the connecting clamp 11 is provided with two symmetrical threaded holes, the outer walls of the sealing cavity 10 are provided with symmetrical rectangular holes 14 on both sides, and the middle part of the pressing sleeve 7 is provided with two symmetrical and rectangular holes 14 which are symmetrical and symmetrical to the sealing cavity. The threaded hole 19 is parallel to the shaped hole, and a sealing groove 20 is set at the upper end of the pressing sleeve. The lower corner seat 12 is threadedly connected with the threaded hole 19 on the pressing sleeve 7, and the upper corner seat 15 is threadedly connected with the hole on the connecting clamp 11. The upper corner seat 15 passes through the symmetrical rectangular hole 14. The piston rod of the hydraulic cylinder 13 is bolted to the upper corner seat 15, and the cylinder base of the hydraulic cylinder 13 is bolted to the lower corner seat 12. The hydraulic cylinder is controlled and driven by an external hydraulic system. The hydraulic compensation system includes a hydraulic cylinder 13, a three-position four-way valve 2 1. Accumulator 22, pressure gauge 23, first non-return valve 24, second non-return valve 2425. Port A of each hydraulic cylinder is connected to a three-position four-way reversing valve through a pipeline. Port B of each hydraulic cylinder is connected to a three-position four-way reversing valve through a pipeline. The three-position four-way reversing valve is respectively connected to the first non-return valve and the second non-return valve through corresponding pipelines. An accumulator is installed on the pipeline between the first non-return valve and the three-position four-way reversing valve. The accumulator is provided with a pressure gauge. The accumulator 22 supplies energy to the hydraulic cylinder 13 when the packing needs to be compressed. After the system is connected to the oil source, the one-way valve 24 opens, and the three-position four-way reversing valve 21 is adjusted to the left position. The oil enters the rod chamber of the hydraulic cylinder 13 from the hydraulic cylinder A port. The pressure in the rodless chamber of the hydraulic cylinder increases, and the oil flows out from the hydraulic cylinder B port and flows into the oil tank through the second one-way valve 25, so that the hydraulic cylinder drives the upper angle seat 15 to move downward, and then drives the pressing sleeve 7 to move downward to compress the packing 8 to achieve sealing. At this time, the three-position four-way reversing valve 21 is adjusted to the middle position, and the oil enters the accumulator 22 to charge the accumulator 22. When the pressure of the pressure sensor 23 on the accumulator 22 reaches a certain value, the system stops connecting to the oil source. When the packing 8 needs to be compressed again, the three-position four-way reversing valve 21 is adjusted to the left position, and the energy stored in the accumulator 22 is released. The oil enters the rod chamber of the hydraulic cylinder 13 from the hydraulic cylinder A port, and the hydraulic cylinder compresses the packing again to achieve sealing.

[0026] The accumulator 22 only needs to be charged periodically, and the motor, oil pump and oil tank can be removed from the system after charging.

[0027] After the packing is added to the oil well, the hydraulic cylinder is first installed, and the compression sleeve compresses the packing added to the oil well to ensure that the oil well polished rod and the packing are in a sealed state. At this time, the packing under the action of the hydraulic cylinder always gives the oil well sealing packing a downward force. As the packing continues to wear, when the packing becomes loose, the accumulator can provide energy supplement to the hydraulic cylinder in time, and the hydraulic cylinder will shrink in time, thereby continuing to compress the packing to ensure that the oil well packing and the polished rod are always in a sealed state, eliminating oil well pollution incidents caused by failure to tighten the packing in time, eliminating production losses, and improving oil well time efficiency. The use of this device is not only of great significance to clean production, energy saving and consumption reduction, but also can reduce the number of packing replacements and well downtime, and increase crude oil production.

[0028] After the packing is added to the oil well, the utility model does not need to frequently adjust and tighten the packing manually. The accumulator automatically compensates the hydraulic energy to make the hydraulic cylinder automatically extend and retract, which reduces the labor intensity of employees, prolongs the service life of the packing, and improves the well opening rate. The device fills the technical gap and has promotion value.

Claims

1. A controllable sealing device for a wellhead polished rod, characterized in that: This wellhead polished rod controllable sealing device comprises a dust cover, a grease chamber, a sealing chamber, a connecting clamp and a hydraulic compensation system. The upper end of the sealing chamber is threadedly connected to the grease chamber, the dust cover is closed at the upper end of the grease chamber, the sealing chamber is threadedly connected to the connecting clamp, a packing and a pressing sleeve are placed in the sealing chamber, and the pressing sleeve is pressed on the packing; the polished rod enters the sealing chamber from the dust cover and passes through the connecting clamp, and the pressing sleeve, the packing and the sponge in the grease chamber are all tightly fitted to the outer wall of the polished rod; two rectangular holes are symmetrically arranged on the sealing chamber wall, two threaded holes are symmetrically arranged in the middle of the pressing sleeve, an upper angle seat is fastened in each threaded hole, and the upper angle seats are all slidably connected to the corresponding rectangular holes, a sealing groove is arranged on the upper end of the pressing sleeve, and lower angle seats are symmetrically arranged in the connecting clamp, a hydraulic cylinder is connected between each pair of upper and lower angle seats, the hydraulic cylinder piston rod is bolted to the upper angle seat, and the hydraulic cylinder oil cylinder base is bolted to the lower angle seat; the hydraulic compensation system comprises the two hydraulic cylinders.

2. The wellhead polished rod controllable sealing device according to claim 1, characterized in that: The hydraulic compensation system also includes an accumulator, a three-position four-way reversing valve, a first one-way valve, and a second one-way valve. The A port of each hydraulic cylinder is connected to the three-position four-way reversing valve through a pipeline, and the B port of each hydraulic cylinder is connected to the three-position four-way reversing valve through a pipeline. The three-position four-way reversing valve is respectively connected to the first one-way valve and the second one-way valve through corresponding pipelines. An accumulator is installed on the pipeline between the first one-way valve and the three-position four-way reversing valve, and the accumulator is provided with a pressure gauge.

3. The wellhead polished rod controllable sealing device according to claim 2, characterized in that: The dust cover is provided with a center hole, the polished rod passes through the center hole and enters the sealing cavity, the dust cover is threadedly connected to the upper end of the grease cavity, the lower end of the dust cover presses the rubber sealing ring on the inner stopper of the grease cavity, and the inner wall of the rubber sealing ring is tightly fitted with the outer wall of the polished rod.

4. The wellhead polished rod controllable sealing device according to claim 3, characterized in that: The lower end of the butter cavity is provided with an external thread, a stepped end face is provided in the butter cavity, a sponge and a stopper are respectively placed on corresponding end faces in the butter cavity, and the sponge in the butter cavity is soaked with butter and fits with the polished rod.

5. The wellhead polished rod controllable sealing device according to claim 4, characterized in that: An internal thread is arranged at the upper end of the sealing chamber, the lower end of the grease chamber is threadedly connected to the upper end of the sealing chamber, an external thread is arranged at the lower end of the sealing chamber, the lower end of the sealing chamber is threadedly connected to a connecting clamp, the connecting clamp is connected to a wellhead clamp, two symmetrical threaded holes are arranged on the outer wall of the connecting clamp, and a lower angle seat is fastened in each threaded hole.

6. The wellhead polished rod controllable sealing device according to claim 5, characterized in that: A sealing groove is arranged at the upper end of the pressing sleeve, an O-type rubber sealing ring is arranged in the sealing groove, and the upper end of the pressing sleeve and the sealing cavity are sealed by the O-type sealing ring.

7. The wellhead polished rod controllable sealing device according to claim 6, characterized in that: Each pair of upper angle seats and lower angle seats coincides with the center plane of the hydraulic cylinder.

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