Packing box for wellhead Christmas tree

Abstract

The utility model relates to the technical field of polish rod sealing, in particular to a packing box for a wellhead Christmas tree. Comprising a hoop head, a connecting seat is fixed to the upper end of the hoop head, rubber gate valves are installed on the two sides of the connecting seat, a vertical cylinder is detachably, fixedly and hermetically connected to the upper end of the connecting seat, a spacer ring is fixed in the vertical cylinder, packing is installed in the vertical cylinder above and below the spacer ring, and a pressure transmission assembly is slidably arranged on the spacer ring; the upper end of the pressure transmission assembly abuts against the lower end of the upper packing, the lower end of the pressure transmission assembly abuts against the upper end of the lower packing, a gland is in threaded connection with the interior of the upper end of the vertical cylinder and abuts against the upper end of the upper packing, and an extrusion assembly is slidably arranged in the connecting base in the axial direction and elastically connected with the connecting base. Through the synergistic effect of the elastic compensation system and the rigid guide structure, the problems that sealing pressure of a traditional packing box cannot be adjusted, and abrasion compensation lags behind are solved, and comprehensive optimization of sealing performance, maintenance efficiency and cost control is achieved.

Description

Technical Field

[0001] This utility model relates to the field of polished rod sealing technology, specifically to packing boxes for wellhead production trees. Background Technology

[0002] In oil extraction, the reciprocating motion of the surface pumping unit drives the downhole pump via the polished rod and sucker rod, pumping crude oil to the surface. During pumping, the polished rod continuously moves up and down at the wellhead. To maintain a seal between the polished rod and the wellhead, a stationary packing box is typically installed at the wellhead, containing packing. The moving polished rod passes through the hollow packing box and the packing, achieving isolation between the downhole and surface environments through the tight fit between the polished rod and the packing. However, some existing packing boxes still use the traditional single-stage packing sealing method, which does not provide an ideal sealing effect.

[0003] Patent document CN204827326U discloses a multi-stage packing box for an oil pumping unit. The box contains packing, and a pressure cap is located at the top. A smooth rod passes through the center of the packing box, packing, and pressure cap. The key feature is the addition of a secondary pressure cap at the bottom of the packing box, followed by a secondary packing box below the secondary pressure cap, and a secondary packing unit containing secondary packing. A smooth rod passes through the center of the packing box, packing, pressure cap, secondary pressure cap, secondary packing box, and secondary packing. However, this design fails to automatically tighten the packing after wear, resulting in a short sealing time for the multi-stage packing box in the oil pumping unit. Utility Model Content

[0004] The main purpose of this invention is to provide a packing box for wellhead production trees that can improve sealing performance and sealing time.

[0005] To achieve the above objectives, the technical solution provided by this utility model is as follows:

[0006] The wellhead Christmas tree packing box includes a clamp head, a connecting seat fixed at the upper end of the clamp head, rubber gate valves installed on both sides of the connecting seat, a vertical cylinder detachably and fixedly sealed at the upper end of the connecting seat, a spacer ring fixed inside the vertical cylinder, packing installed in the vertical cylinder above and below the spacer ring, a pressure transmission component slidably mounted on the spacer ring, the pressure transmission component can slide in the axial direction of the vertical cylinder, the upper end of the pressure transmission component tightly abuts against the lower end of the upper packing, the lower end of the pressure transmission component tightly abuts against the upper end of the lower packing, a pressure cap is internally threaded to the upper end of the upper packing, the pressure cap tightly abuts against the upper end of the upper packing, a compression component is slidably mounted in the axial direction inside the connecting seat, the compression component is elastically connected to the connecting seat, the upper end of the compression component tightly abuts against the lower end of the lower packing.

[0007] Specifically, the partition ring and the vertical cylinder are integrally formed.

[0008] Specifically, the pressure transmission assembly includes an upper ring and a lower ring, with a spacer ring located between the upper and lower rings. The upper and lower rings are fixedly connected by multiple uprights, the axial direction of which is parallel to the axial direction of the vertical cylinder. The uprights pass through the spacer ring and are slidably connected to it.

[0009] Specifically, the extrusion assembly includes a top ring, the upper end of which is pressed against the lower end of the packing below. The top ring is connected to the connecting seat via a telescopic rod and a spring.

[0010] Specifically, the axial direction of the telescopic rod is parallel to the axial direction of the vertical cylinder. The telescopic rod includes a sleeve, the upper end of which is fixedly connected to the lower end of the top ring. An insert rod is slidably arranged inside the sleeve, and the lower end of the insert rod is fixedly connected to the connecting seat.

[0011] Specifically, the connecting seat has a groove corresponding to the spring, the lower end of the spring is located in the groove, and the lower end of the plug rod is fixed in the groove.

[0012] Specifically, the telescopic rod is located inside the spring.

[0013] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0014] 1. Through the coordinated design of the pressure transmission component and the elastic compression component, a bidirectional automatic wear compensation function is achieved for the upper and lower packings. This avoids the pressure attenuation problem caused by wear in traditional single-stage seals, thus improving sealing efficiency.

[0015] 2. The spacer ring divides the vertical shaft into upper and lower sealing chambers, forming a physically isolated double sealing layer. If one layer of packing fails, the other layer can still maintain a basic seal, reducing the risk of wellhead leakage.

[0016] 3. The built-in telescopic rod of the spring provides axial linear motion constraint, preventing the top ring from radially shifting due to the eccentric movement of the smooth rod, thus extending the spring's lifespan.

[0017] 4. The vertical cylinder and the connecting seat are connected by threads, and the gland can be unscrewed, allowing for tool-free replacement of the packing. The upper and lower packings can be disassembled and installed independently without the need for overall replacement, reducing maintenance costs.

[0018] 5. The upright slides through the spacer ring to ensure that the pressure transmission assembly maintains uniform pressure distribution when sliding axially, avoiding packing tearing caused by local stress concentration.

[0019] 6. The spring is embedded in the groove of the connecting seat and positioned in conjunction with the fixed end of the telescopic rod to prevent twisting or lateral displacement during spring compression. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view of the packing box.

[0021] Figure 2 This is a sectional view of the separate structure of the connecting seat, the vertical cylinder, and the pressure cap.

[0022] The parts in the attached diagram are named as follows: 1. Clamp head, 2. Rubber gate valve, 3. Connecting seat, 4. Vertical cylinder, 5. Spacer ring, 6. Pressure cap, 7. Upper ring, 8. Vertical rod, 9. Lower ring, 10. Top ring, 11. Spring, 12. Sleeve, 13. Groove, 14. Insert rod, 15. Plain rod. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0024] Example 1: Refer to Figures 1-2 As shown, the wellhead production tree packing box includes a clamp head 1, a connecting seat 3 fixed to the upper end of the clamp head 1, rubber gate valves 2 installed on both sides of the connecting seat 3, and a vertical cylinder 4 detachably and securely connected to the upper end of the connecting seat 3. The connecting seat 3 and the vertical cylinder 4 are connected by a threaded seal.

[0025] A spacer ring 5 is fixed inside the vertical cylinder 4, and the spacer ring 5 is integrally formed with the vertical cylinder 4. Packing is installed in the vertical cylinder 4 above and below the spacer ring 5. A pressure transmission component is slidably arranged on the spacer ring 5. The pressure transmission component can slide in the axial direction of the vertical cylinder 4. The upper end of the pressure transmission component is tightly pressed against the lower end of the upper packing, and the lower end of the pressure transmission component is tightly pressed against the upper end of the lower packing.

[0026] The pressure transmission assembly includes an upper ring 7 and a lower ring 9. A spacer 5 is located between the upper ring 7 and the lower ring 9. The upper ring 7 and the lower ring 9 are fixedly connected by multiple uprights 8. The axial direction of the uprights 8 is parallel to the axial direction of the vertical cylinder 4. The uprights 8 pass through the spacer 5 and are slidably connected to the spacer 5.

[0027] The upper end of the vertical cylinder 4 is internally threaded with a pressure cap 6, which is tightly pressed against the upper end of the packing above.

[0028] An extrusion assembly is slidably disposed in the axial direction within the connecting seat 3. The extrusion assembly is elastically connected to the connecting seat 3, and the upper end of the extrusion assembly is tightly pressed against the lower end of the packing below.

[0029] The extrusion assembly includes a top ring 10, the upper end of which is pressed against the lower end of the packing below. The top ring 10 is connected to the connecting seat 3 by a spring 11. The connecting seat 3 has a groove 13 corresponding to the spring 11, and the lower end of the spring 11 is located in the groove 13.

[0030] As the bare rod 15 moves up and down through the packing box, the packing on the upper and lower sides can seal the bare rod 15.

[0031] Under the elastic force of spring 11, top ring 10 presses tightly against the lower packing. The lower packing, through lower ring 9, upright rod 8, and upper ring 7, presses tightly against the upper packing. The upper packing is limited by pressure cap 6. During the reciprocating motion of polished rod 15, the packing on both the upper and lower sides can be squeezed. After the packing is worn, it can maintain its effective seal against polished rod 15, thereby improving the sealing effect and sealing time of polished rod 15.

[0032] When replacing the packing, unscrew the cap 6 from the upper end of the vertical cylinder 4 and suspend it at the height of the smooth rod 15. Unscrew the vertical cylinder 4 from the connecting seat 3, and move the vertical cylinder 4 upward away from the connecting seat 3. Pull the upper packing out from the upper end of the vertical cylinder 4 and pull the lower packing out from the lower end of the vertical cylinder 4. Then, new packing can be installed in the vertical cylinder 4 on both sides above and below the spacer ring 5.

[0033] After the packing is replaced, screw the cap 6 into the upper end of the vertical cylinder 4, and then screw the lower end of the vertical cylinder 4 into the connecting seat 3. The top ring 10 can press tightly against the lower end of the packing below, and the packing above presses tightly against the packing above through the lower ring 9, the vertical rod 8 and the upper ring 7.

[0034] Example 2: Based on Example 1, referring to... Figures 1-2 As shown, the top ring 10 is connected to the connecting seat 3 via a telescopic rod, which is located inside the spring 11. The axial direction of the telescopic rod is parallel to the axial direction of the vertical cylinder 4.

[0035] The telescopic rod includes a sleeve 12, the upper end of which is fixedly connected to the lower end of the top ring 10. An insert rod 14 is slidably disposed inside the sleeve 12, the lower end of which is fixedly connected to the connecting seat 3, and the lower end of the insert rod 14 is fixed in the groove 13.

[0036] By setting a telescopic rod, when the lower end of the vertical cylinder 4 is screwed into the connecting seat 3, the top ring 10 can be prevented from rotating, the spring 11 can be prevented from shifting, and the spring 11 can be guaranteed to apply effective pressure to the top ring 10.

[0037] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A packing box for wellhead Christmas tree, comprising a clamp head (1), a connecting seat (3) is fixed on the upper end of the clamp head (1), rubber gate valves (2) are installed on both sides of the connecting seat (3), a vertical cylinder (4) is detachably fixed and sealingly connected on the upper end of the connecting seat (3), characterized in that, The cylindrical column (4) is fixed with a partition ring (5), the cylindrical column (4) above and below the partition ring (5) is provided with a disc ring, the partition ring (5) is provided with a pressure transmission assembly, the pressure transmission assembly can slide in the axial direction of the cylindrical column (4), the upper end of the pressure transmission assembly abuts the lower end of the disc ring above, the lower end of the pressure transmission assembly abuts the upper end of the disc ring below, the upper end of the cylindrical column (4) is screw connected with a gland (6), the gland (6) abuts the upper end of the disc ring above, the axial direction of the connecting seat (3) is provided with an extrusion assembly, the extrusion assembly is elastically connected with the connecting seat (3), the upper end of the extrusion assembly abuts the lower end of the disc ring below.

2. The swivel for a wellhead Christmas tree according to claim 1, characterized in that The partition ring (5) is integrally formed with the cylindrical column (4).

3. The swivel for a wellhead Christmas tree according to claim 1, characterized in that The pressure transmission assembly comprises an upper ring (7) and a lower ring (9), the partition ring (5) is located between the upper ring (7) and the lower ring (9), the upper ring (7) and the lower ring (9) are fixedly connected through a plurality of vertical rods (8), the axial direction of the vertical rod (8) is parallel to the axial direction of the cylindrical column (4), the vertical rod (8) penetrates the partition ring (5), and the vertical rod (8) is slidably connected with the partition ring (5).

4. The swivel for a wellhead Christmas tree according to claim 1, wherein The extrusion assembly comprises a top ring (10), the upper end of the top ring (10) abuts the lower end of the disc ring below, the top ring (10) is connected with the connecting seat (3) through a telescopic rod, and the top ring (10) is connected with the connecting seat (3) through a spring (11).

5. The swivel for a wellhead Christmas tree according to claim 4, characterized in that The axial direction of the telescopic rod is parallel to the axial direction of the cylindrical column (4), the telescopic rod comprises a sleeve (12), the upper end of the sleeve (12) is fixedly connected with the lower end of the top ring (10), and the sleeve (12) is slidably provided with a plug rod (14) in the sleeve (12).

6. The swivel for a wellhead Christmas tree according to claim 5, characterized in that The connecting seat (3) is provided with a groove (13) corresponding to the spring (11) in the connecting seat (3), the lower end of the spring (11) is located in the groove (13), and the lower end of the plug rod (14) is fixed in the groove (13).

7. The swivel for a wellhead Christmas tree according to claim 4, wherein The telescopic rod is located inside the spring (11).

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