Centrifugal Compressor Thrust Balance Chamber Design
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Solution Overview
Problem
Existing centrifugal compressors require a separate thrust bearing to support the rotary shaft due to thrust forces generated by fluid pressure, which increases shaft length, vibration, size, and weight.
Innovation Solution
A compressor design that includes a thrust force adjusting part with an outer sealing part, an inner sealing part, and a throttle formation part to automatically balance thrust forces without a thrust bearing, using a self-regulating throttle mechanism to adjust the gap width and pressure in the axial direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thrust bearing is provided to support the rotary shaft, then the thrust force is balanced, but the length of the rotary shaft increases
Solution Approach 1:
The invention extracts the thrust bearing from the system and replaces it with a balance chamber formed directly in the housing. The balance chamber utilizes fluid pressure from the compression process itself to balance the thrust force on the impeller, eliminating the need for a separate thrust bearing component and thereby reducing the rotary shaft length.
Solution Approach 2:
The invention merges the thrust balance function into the housing structure by forming a balance chamber within it. This integration combines the housing's structural support function with the thrust balance function, allowing the same structure to serve multiple purposes without requiring additional components like a thrust bearing.
2Reliability
If a thrust bearing is provided to support the rotary shaft, then the thrust force is balanced, but the size and weight of the compressor increase
Solution Approach 1:
The invention removes the thrust bearing component entirely and replaces its function with a balance chamber that uses the existing fluid system. This extraction eliminates the weight of the thrust bearing while maintaining thrust balance capability through the balance chamber's fluid pressure mechanism.
Solution Approach 2:
The invention combines the thrust balance function with the existing housing structure, allowing the housing to serve dual purposes: structural support and thrust balance. This merging eliminates the need for separate thrust bearing components, thereby reducing the overall compressor weight.
3Reliability
If a thrust bearing is provided to support the rotary shaft, then the thrust force is balanced, but shaft vibration increases
Solution Approach 1:
The invention extracts the thrust bearing and replaces it with a balance chamber system that uses fluid pressure to balance thrust forces. This eliminates the mechanical contact and potential vibration sources associated with thrust bearings, resulting in reduced shaft vibration while maintaining thrust balance.
4Loss of substance
If the gap in the throttle part is narrowed, then the amount of leakage from the balance chamber is reduced, but the pressure in the second space and third space increases
Solution Approach 1:
The invention implements a feedback mechanism where the throttle part's gap width automatically adjusts based on the pressure differential across the balance piston. When pressure increases, the gap narrows to reduce leakage; when pressure decreases, the gap widens to allow more leakage. This self-regulating feedback system maintains pressure balance without external control.
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 design allows for the automatic return of the rotary shaft to its original position by balancing thrust forces, reducing the length of the rotary shaft and minimizing vibration and size, while maintaining effective sealing and cooling the motor using the leaking gas.
Implementation Method 1
a throttle formation part which has a throttle part in which the gap between the back surface and the casing in the axial direction is narrowed
Implementation Method 2
an outer sealing part which seals a gap between the back surface and the casing; an inner sealing part which is disposed at a position away from the outer sealing part inward in a radial direction centered on the axis and seals a gap between the back surface and the casing
Implementation Method 3
the high pressure of the fluid after compression acts on both surfaces of the impeller in the axial direction in the outer region of the impeller in the radial direction
Implementation Method 4
a balance piston which is disposed in the balance chamber and has a thrust force balancing surface facing the high-pressure-side fluid
Data Source
AI summary
A compressor includes a thrust force adjusting part which is configured to adjusts a thrust force between a back surface of a disc part in an impeller and a casing. The thrust force adjusting part includes an outer sealing part which seals a gap between the back surface and the casing, an inner sealing part which seals the gap at a position away inward in a radial direction, and a throttle formation part which has a throttle part in which the gap in an axial direction is formed to be narrowed inward in the radial direction. An outer space sandwiched by the outer sealing part and the inner sealing part and an inner space sandwiched by the inner sealing part and the throttle part are formed the gap. The width of the throttle part is narrower than the width of the inner space.