Direct drive screw pump self-lubricating packing seal device

Abstract

The utility model discloses a kind of direct-drive screw pump self-lubricating packing sealing devices, including polished rod, lower packing box is arranged on polished rod, righting copper sleeve and lower packing rope are installed in lower packing box and are compressed by lower pressing cap;The top of lower packing box is provided with pressure-maintaining cavity body, the top of pressure-maintaining cavity body is provided with inner hole, upper packing rope is installed in inner hole and is compressed by upper pressing cap;Valve is provided on pressure-maintaining cavity body and is communicated with pressure-maintaining cavity, lubricating sealing grease is injected into pressure-maintaining cavity by valve, lubricating sealing grease is infiltrated into the gap of polished rod and pressure-maintaining cavity body and lower pressing cap by flow channel;Piston is arranged in pressure-maintaining cavity, spring is sleeved on pressure-maintaining cavity body, one end is in contact with piston, the other end is in contact with spring locknut, the pre-tightening force of spring is applied on piston to pressurize lubricating sealing grease, with wellhead working pressure same pressure, form pressure-maintaining sealing cavity, reduce the pre-tightening force that packing pressing cap applies to packing rope, effectively reduce the friction of packing rope and polished rod.

Description

Technical Field

[0001] This utility model relates to the field of oil extraction, and in particular to a self-lubricating packing seal device for a direct-drive screw pump. Background Technology

[0002] In normal oilfield screw pump well production, the well's production fluid is sealed by an old-fashioned packing box sealing device. The sealing of the well's production pressure is achieved by the packing cap applying preload to the packing rope and the rotating drive rod working closely together to achieve the well's production pressure seal, thus enabling normal production.

[0003] Because the packing cap applies preload to the packing rope, friction will occur between the packing rope and the drive rod. Long-term use will inevitably cause wear on the packing rope and the drive rod. In actual oilfield production, visible grooves will appear on the packing and drive rod after 3 to 6 months, causing well sealing failure and production to stop. Summary of the Invention

[0004] This utility model provides a self-lubricating packing seal device for a direct-drive screw pump. By pressurizing the lubricating grease in the pressure-holding chamber, a pressure value equal to the wellhead working pressure can be generated, forming a pressure-holding seal chamber. This reduces the preload applied to the packing rope by the packing cap, effectively reducing friction between the packing rope and the polished rod, and can provide long-term, long-life service for oilfield screw pump production. The specific technical solution is as follows:

[0005] A self-lubricating packing seal device for a direct-drive screw pump includes a polished rod. The polished rod is equipped with a lower packing box, a centering copper sleeve, and a lower packing rope, which are installed inside the lower packing box and secured by a lower pressure cap. A pressure-holding chamber body is located above the lower packing box, with an inner hole at the top. An upper packing rope is installed inside the inner hole and secured by an upper pressure cap. A valve communicating with the pressure-holding chamber is provided on the pressure-holding chamber body, allowing lubricating grease to be injected into the pressure-holding chamber. The lubricating grease can seep into the gaps between the polished rod, the pressure-holding chamber body, and the lower pressure cap through a flow channel, allowing the packing rope to absorb it. A piston is installed inside the pressure-holding chamber, with a spring sleeve fitted onto the pressure-holding chamber body. One end of the spring sleeve abuts against the piston, and the other end abuts against a spring-locking nut on the pressure-holding chamber body. The preload of the spring acts on the piston to pressurize the lubricating grease, generating a pressure value identical to the wellhead working pressure. An upper packing locking nut for securing the upper pressure cap is located above the spring-locking nut.

[0006] Furthermore, the bottom of the pressure-holding cavity body is provided with an internal thread, and the top of the lower packing box is provided with an external thread that matches the internal thread of the pressure-holding cavity body. The pressure-holding cavity body and the lower packing box are threadedly connected to achieve the pressing and fixing of the lower pressure cap.

[0007] Furthermore, the lower pressure cap is provided with an oil passage hole, which is connected to the flow channel on the pressure holding chamber body, so that the lubricating grease in the pressure holding chamber can lubricate the lower packing rope through the oil passage hole.

[0008] Furthermore, the outer surface of the pressure cap is provided with two annular sealing grooves, and a sealing ring is installed in each of the two annular sealing grooves to seal the pressure cap with the pressure holding chamber body and the lower packing box.

[0009] Furthermore, the straightening copper sleeve has a T-shaped structure and a lubrication channel on its inner surface. The straightening copper sleeve abuts against the step of the lower packing box and is used to straighten and lubricate the polished rod to reduce wear on the polished rod during rotation.

[0010] Furthermore, the piston has annular sealing grooves on both its inner and outer surfaces, and a sealing ring that seals with the pressure-holding chamber body is installed on the annular sealing grooves.

[0011] Furthermore, the top of the pressure-holding cavity body is provided with external threads, and the spring locking nut is screwed onto the pressure-holding cavity body, abutting against the spring.

[0012] Furthermore, the valve is located on one side of the bottom of the pressure-holding chamber body.

[0013] This utility model has a simple structure and reasonable design. The self-lubricating packing seal device of the direct-drive screw pump changes the old working method of packing rope and drive rod. Lubricating grease is added, and the preload of the spring acts on the piston to pressurize the lubricating grease, which can generate the same pressure value as the working pressure at the wellhead, forming a pressure-holding sealing cavity. This reduces the preload applied to the packing rope by the packing cap, effectively reducing the friction between the packing rope and the rod, and can serve the production work of oilfield screw pumps for a long time and a long service life. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0015] To better understand the purpose, function, and specific design of this utility model, the self-lubricating packing seal device for a direct-drive screw pump of this utility model will be described in further detail below with reference to the accompanying drawings.

[0016] like Figure 1As shown, the self-lubricating packing seal device for a direct-drive screw pump of this utility model includes a smooth rod 14, through which a lower packing box 2 is threaded. A straightening copper sleeve 1 and a lower packing rope 3 are installed inside the lower packing box 2 and pressed together by a lower pressure cap 4. A pressure-holding chamber body 6 is provided above the lower packing box 2. The top of the pressure-holding chamber body 6 has an inner hole, and an upper packing rope 11 is installed in the inner hole and pressed together by an upper pressure cap 12. A valve 5 is provided on the pressure-holding chamber body 6, which communicates with the pressure-holding chamber 7. Lubricating grease can be injected into the pressure-holding chamber 7 through the valve 5. The lubricating grease can seep into the gap between the smooth rod 14, the pressure-holding chamber body 6, and the lower pressure cap 4 through the flow channel 15, so that the packing rope can absorb it.

[0017] A piston 8 is installed inside the pressure-holding chamber 7. A spring 9 is fitted onto the pressure-holding chamber body 6. One end of the spring 9 abuts against the piston 8, and the other end of the spring 9 abuts against the spring locking nut 10 on the pressure-holding chamber body 6. The preload of the spring 9 acts on the piston 8 to pressurize the lubricating grease, generating a pressure value identical to the wellhead working pressure. Above the spring locking nut is an upper packing locking nut 13 for tightening the upper pressure cap.

[0018] The bottom of the pressure-holding cavity body 6 is provided with an internal thread, and the top of the lower packing box 2 is provided with an external thread that matches the internal thread of the pressure-holding cavity body 6. The pressure-holding cavity body 6 and the lower packing box 2 are threadedly connected to achieve the pressing and fixing of the lower pressure cap 4.

[0019] The lower pressure cap 4 is provided with an oil passage hole 16, which is connected to the flow channel 15 on the pressure holding chamber body 6, so that the lubricating grease in the pressure holding chamber 7 can be lubricated through the oil passage hole 16 to lubricate the lower packing rope 3.

[0020] The outer surface of the lower pressure cap 4 is provided with two annular sealing grooves, and a sealing ring is installed in each of the two annular sealing grooves to seal the lower pressure cap 4 with the pressure holding chamber body 6 and the lower packing box 2.

[0021] The centering copper sleeve 1 has a T-shaped structure and a lubrication channel on its inner surface. Lubricating grease seeps into the lubrication channel through the gap between the polished rod 14 and the centering copper sleeve 1. The centering copper sleeve abuts against the step of the lower packing box and is used to center and lubricate the polished rod to reduce wear on the polished rod during rotation.

[0022] Both the inner and outer surfaces of the piston 8 are provided with annular sealing grooves, and a sealing ring that seals with the pressure-holding chamber body 6 is installed on the annular sealing groove.

[0023] The top of the pressure-holding cavity body 6 is provided with external threads, and the spring locking nut 10 is tightened on the pressure-holding cavity body 6, which abuts against the spring 9.

[0024] During installation, insert the centering copper sleeve 1, lower packing rope 3, and lower pressure cap 4 into the lower packing box 2, and then fit them into the smooth rod 14. Next, insert the piston 8 and spring 9 into the pressure holding chamber body 6, screw in the spring lock nut 10, install the valve 5, and then fit the pressure holding chamber body 6 into the smooth rod 14, threadedly connecting it to the lower packing box 2. Insert the upper packing rope 11 into the inner hole of the pressure holding chamber body 6, tighten the upper pressure cap, and finally thread the upper packing lock nut 13 into the pressure holding chamber body 6 to complete the assembly.

[0025] During use, lubricating grease is added to the pressure-holding chamber 7 through valve 5, spring 9 is tightened, and the pressure in the pressure-holding chamber 7 is tested to be the same as the oil well production pressure. Then the oil well can be started to work normally.

[0026] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A self-lubricating packing seal device for a direct-drive screw pump, comprising a smooth rod, characterized in that, The polished rod is fitted with a lower packing box, and the straightening copper sleeve and lower packing rope are installed inside the lower packing box and tightened by the lower pressure cap. A pressure-holding chamber body is located above the lower packing box, with an inner hole at the top. The upper packing rope is installed inside the inner hole and tightened by the upper pressure cap. A valve communicating with the pressure-holding chamber is installed on the pressure-holding chamber body, allowing lubricating grease to be injected into the pressure-holding chamber. The lubricating grease can seep into the gaps between the polished rod, the pressure-holding chamber body, and the lower pressure cap through a flow channel, allowing the packing rope to absorb it. A piston is installed inside the pressure-holding chamber, and a spring is fitted onto the pressure-holding chamber body, with one end contacting the piston and the other end contacting the spring locking nut on the pressure-holding chamber body. The preload of the spring acts on the piston to pressurize the lubricating grease, generating a pressure value identical to the wellhead working pressure. An upper packing locking nut for tightening the upper pressure cap is located above the spring locking nut.

2. The self-lubricating packing seal device for a direct-drive screw pump according to claim 1, characterized in that, The bottom of the pressure-holding cavity body is provided with an internal thread, and the top of the lower packing box is provided with an external thread that matches the internal thread of the pressure-holding cavity body. The pressure-holding cavity body and the lower packing box are threadedly connected to achieve the pressing and fixing of the lower pressure cap.

3. The self-lubricating packing seal device for a direct-drive screw pump according to claim 2, characterized in that, The lower pressure cap is provided with an oil passage hole, which is connected to the flow channel on the pressure holding chamber body, so that the lubricating grease in the pressure holding chamber can be used to lubricate the lower packing rope through the oil passage hole.

4. The self-lubricating packing seal device for a direct-drive screw pump according to claim 3, characterized in that, The outer surface of the pressure cap is provided with two annular sealing grooves, and a sealing ring is installed in each of the two annular sealing grooves to seal the pressure cap with the pressure holding chamber body and the lower packing box.

5. The self-lubricating packing seal device for a direct-drive screw pump according to claim 1, characterized in that, The aforementioned straightening copper sleeve has a T-shaped structure and a lubrication channel on its inner surface. The straightening copper sleeve abuts against the step of the lower packing box and is used to straighten and lubricate the polished rod to reduce wear on the polished rod during rotation.

6. The self-lubricating packing seal device for a direct-drive screw pump according to claim 1, characterized in that, The piston has annular sealing grooves on both its inner and outer surfaces, and a sealing ring that seals with the pressure-holding chamber body is installed on the annular sealing grooves.

7. The self-lubricating packing seal device for a direct-drive screw pump according to claim 1, characterized in that, The top of the pressure-holding chamber body is provided with external threads, and the spring locking nut is screwed onto the pressure-holding chamber body, contacting the spring.

8. The self-lubricating packing seal device for a direct-drive screw pump according to claim 1, characterized in that, The valve is located on one side of the bottom of the pressure-holding chamber body.

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