Polished Rod Stuffing Box with Dynamic Coaxial Sealing
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Solution Overview
Problem
The existing polished rod sealing devices in oil pumping machines suffer from eccentric wear of the sealing packing due to non-coaxial movement between the polished rod and the stuffing box, leading to short tightening and replacement cycles, high labor intensity, severe wear on the polished rod, and increased energy consumption.
Innovation Solution
A polished rod sealing device with a built-in stuffing box and flexible connection units that allows dynamic coaxiality between the polished rod and the stuffing box, combined with a solid lubricator for reduced friction and wear, ensuring the sealing packing remains dynamically coaxial and lubricated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stuffing box is fixed relative to the oil pipe, then the structure is simple and easy to manufacture, but the sealing packing suffers from eccentric wear due to non-coaxial movement between the polished rod and stuffing box
Solution Approach 1:
The stuffing box is transformed from a fixed structure to a dynamic structure that can move radially and rotate angularly. The flexible connection units (first and second flexible connection units) enable the stuffing box body to follow the polished rod's motion trajectory, maintaining dynamic coaxiality during operation. This dynamic adaptation eliminates eccentric wear while preserving sealing effectiveness.
Solution Approach 2:
The sealing device is divided into modular components: the stuffing box body, press ring, press ring liner, gasket, gasket liner, and flexible connection units. This segmentation allows the stuffing box to move independently relative to the oil pipe while maintaining sealing function, resolving the contradiction between structural simplicity and sealing reliability.
2Reliability
If the sealing packing is tightly compressed to improve sealing, then sealing effectiveness increases, but the polished rod suffers from severe wear and shortened service life
Solution Approach 1:
A solid lubricator is introduced as an intermediary substance between the polished rod and sealing packing. The lubricator reduces friction and wear while allowing the sealing packing to maintain sufficient compression for effective sealing. This mediator resolves the contradiction between sealing effectiveness and polished rod durability.
3Reliability
If the sealing packing is tightly compressed to achieve sealing, then sealing is improved, but energy consumption at the stuffing box node increases
Solution Approach 1:
The dynamic coaxial movement of the stuffing box reduces friction and resistance during polished rod motion. By maintaining coaxiality through radial and angular displacements, the system minimizes energy loss while preserving sealing function, thus resolving the contradiction between sealing effectiveness and energy consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution prevents eccentric wear of the sealing packing, extends the service life of the polished rod and sealing packing, and reduces energy consumption by maintaining dynamic coaxiality and continuous lubrication.
Implementation Method 1
the bottom of the built-in stuffing box is connected via the first flexible connection unit to the oil pipe enlargement base, the top of the built-in stuffing box is connected via the second flexible connection unit to the oil pipe enlargement press cap
Implementation Method 2
a solid lubricator, which is arranged at the top of the oil pipe enlargement press cap and has a lubricating material storage chamber that is large enough, the components of a solid lubricating material stored in the lubricating material storage chamber
Data Source
AI summary
A polished rod sealing device for an oil pumping machine includes a built-in stuffing box. The built-in stuffing box is arranged inside oil pipe enlargement press cap and can seal the polished rod of the oil pumping machine. The sealing device maintains dynamic coaxiality between the polished rod and the stuffing box, and reduces eccentric wear of the sealing packing resulted from the polished rod. The sealing device also provides lubrication between the polished rod and the sealing packing.