Compressor Rotor Tie Rod Sealing and Assembly
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Solution Overview
Problem
Existing compressor rotors face challenges in maintaining tight alignment and sealing to prevent leakage of compressed medium, especially when using complex rotors with thru-bolts that extend through the rotor, which can lead to potential leaks and safety hazards with high-pressure gases.
Innovation Solution
A rotor design featuring solid stubs and a tie rod configuration where the tie rod does not contact the solid stubs, with a nut applying pre-load to the impellers, and a cavity in the impeller to house the tie rod, ensuring no leakage and easy access for assembly, using flanges and bolts for secure connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thru-bolt is used to connect impellers and apply load, then the impeller assembly can be held tight, but the rotor creates a potential leaking path for compressed medium between the thru-bolt and the hollow rotor
Solution Approach 1:
The patent extracts the thru-bolt from the hollow rotor configuration and replaces it with a solid first stub that extends through the impeller assembly. The tie rod is threaded into the solid second stub, eliminating the need for a hollow rotor and the associated leakage path between the bolt and rotor interior.
Solution Approach 2:
The patent uses a sealing element (gland packing) that acts as a flexible sealing barrier around the tie rod where it passes through the first impeller. This flexible sealing mechanism prevents compressed medium from escaping along the tie rod, addressing the leakage issue while maintaining the structural integrity of the connection.
2Ease of operation
If a thru-bolt extends fully under the bearing and seal zone with an extremity accessible from outside, then load can be applied to the bolt, but access to the bolt becomes complicated and sealing becomes difficult
Solution Approach 1:
The patent segments the connection system into distinct components: a solid first stub, a solid second stub, a tie rod, and a nut. The nut is positioned within the first impeller's cavity, allowing load application from the impeller side rather than requiring external access. This segmentation enables reliable sealing while maintaining ease of operation.
Solution Approach 2:
The patent changes the dimensional arrangement by positioning the nut within the cavity of the first impeller rather than requiring external access to the bolt end. This internal positioning within the impeller structure allows for easier access and more reliable sealing compared to extending the bolt through the entire rotor with external access.
3Stability of the object's composition
If pins and keys are used to provide driving connection between impeller assembly and stubs, then rotational connection is achieved, but the rotor is difficult to compress and align during assembly
Solution Approach 1:
The patent applies preliminary action by pre-assembling the tie rod with the solid second stub and positioning the nut within the first impeller's cavity before final assembly. The cavity is prepared in advance to accommodate the tie rod end and nut, facilitating easier alignment and assembly of the entire rotor structure.
Solution Approach 2:
The patent introduces the cavity within the first impeller as an intermediary structure that facilitates the connection between the tie rod and the impeller assembly. This cavity serves as a mediator that simplifies the assembly process by providing a pre-configured space for the tie rod end and nut, eliminating the need for complex external alignment procedures.
Data Source
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AI summary
Method and rotor for a compressor. The rotor includes a solid first stub having a first end configured to engage with a corresponding bearing and a second end having a flange configured to be attached by bolts to a corresponding flange of a first impeller of the compressor; a tie rod configured to pass through the first impeller of the compressor; a nut being configured to engage a threaded region of the first end of the tie rod; and a solid second stub having a first end configured to receive the threaded portion of the second end of the tie rod and a second end configured to engage with a corresponding bearing. The tie rod does not contact the solid first stub.