Internally Pressurised Seal Rings Thermal Distortion
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Solution Overview
Problem
Internally pressurized high-duty mechanical face seals face challenges with thermal distortion, leading to increased friction and leakage due to uncontrolled heat transfer and thermal gradients, which are not effectively stabilized in conventional designs.
Innovation Solution
The solution involves concentrating heat transfer to and from the seal rings adjacent the sealing faces, using hydrodynamic features like grooves or recesses on the sealing faces to manage thermal distortion, and employing thermally insulative materials and shroud members to control heat distribution, thereby reducing thermal gradients and maintaining hydrostatic support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If heat transfer is concentrated to portions adjacent the sealing faces, then thermal distortion is reduced, but heat transfer complexity increases
Solution Approach 1:
The patent applies local quality by concentrating heat transfer to specific portions of the seal rings adjacent to the sealing faces. This is achieved through thermally insulative material positioned at the inner and outer peripheries of the seal rings, which isolates these regions thermally. Consequently, heat transfer occurs primarily at the localized areas near the sealing faces, reducing thermal gradients and minimizing thermal distortion of the seal rings while maintaining stable sealing performance.
2Stability of the object's composition
If thermally insulative material is used, then thermal gradients are reduced, but heat dissipation capability decreases
Solution Approach 1:
The thermally insulative material is strategically positioned only at the inner and outer peripheries of the seal rings, not throughout the entire structure. This localized insulation creates a thermal gradient control zone at the critical sealing face regions while allowing heat dissipation in other areas. The insulative material has low thermal conductivity, which stabilizes temperatures at the sealing interfaces where thermal distortion would be most harmful, while the rest of the seal ring structure can still dissipate heat effectively.
3Stress or pressure
If seal rings are designed for internal pressurisation, then radial section must be large, but thermal distortion control becomes difficult
Solution Approach 1:
The patent resolves this contradiction by applying local thermal insulation at the peripheries of large radial section seal rings designed for internal pressurisation. The thermally insulative material creates localized thermal management zones that prevent heat from propagating into the bulk of the seal ring structure. This allows the seal rings to maintain their large radial section necessary for withstanding high internal pressures while the insulated portions prevent thermal distortion, achieving both pressure resistance and thermal stability simultaneously.
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
This approach significantly reduces thermal distortion and maintains hydrostatic support, minimizing leakage and ensuring stable sealing performance even under high internal pressures and varying temperatures.
Implementation Method 1
a first portion of the at least one seal ring is surrounded by thermally insulative material to reduce heat transfer to and from the at least one seal ring at a portion of the seal ring away from the sealing faces
Implementation Method 2
When the process fluid is outside the seal rings, the solids will be centrifuged away from the seal rings and associated components
Implementation Method 3
concentrating heat transfer to and from the seal rings to the portions of the seal rings adjacent the sealing faces... thereby reducing rotation of the sealing faces and minimising the reduction in hydrostatic support
Data Source
Figure 1~2
Figure 3~4
AI summary
An internally pressurised seal (10) assembly has a first seal ring (40) mounted in fixed axial and rotational relationship and sealed with respect to one of a pair of relatively rotatable components and a second seal ring (100) moveable axially but fixed rotationally and sealed with respect to the other of the pair of relatively rotatably components, the second seal ring is urged resiliently towards the first seal ring, so that a radial sealing face of the first seal ring engages a radial sealing face of the second seal ring, a process chamber (22) is formed at the inboard side of the seal rings, said process chamber opening to the outside of the seal rings, and a barrier chamber (16) is provided at the outboard side of the seal rings, the barrier chamber opening to the inside of the seal rings, the external circumferential surface of the seal rings are shielded from process fluid in the process chamber by shroud members (62) which ensure that heat transfer from the process fluid to the seal rings predominantly occurs at the outer regions of the seal rings adjacent the sealing faces, and a sleeve (70) is secured internally of each seal ring which ensure that heat transfer between the seal rings and a barrier fluid in the barrier chamber predominantly occurs at the radially extending surfaces of the seal rings adjacent the sealing faces.