Compressor Cover Centering Guide Elements
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Solution Overview
Problem
Turbomachine housings face challenges in minimizing radial clearance for shaft seals due to thermal expansion and manufacturing tolerances, which can lead to leakage and operational safety issues, especially in large covers with diameters over 1000 mm.
Innovation Solution
The housing design includes radially projecting shoulders for secure fastening and a centering mechanism with guide elements to ensure precise alignment and support of the cover relative to the casing, allowing for relative movement due to thermal expansion while maintaining operational safety, and incorporating a dry gas seal with a heater for extreme temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If radial clearance is minimized for shaft seals, then leakage is reduced, but thermal expansion and manufacturing tolerances cause clearance reduction leading to operational safety issues
Solution Approach 1:
The housing is divided into a stationary casing and a rotating cover that can move axially. This segmentation allows the cover to accommodate thermal expansion and manufacturing tolerances while maintaining minimal radial clearance for the shaft seal, thus reducing leakage without compromising operational safety.
Solution Approach 2:
The cover is designed with axial mobility relative to the casing, allowing it to dynamically adjust its position in response to thermal expansion and manufacturing variations. This dynamic adjustment maintains optimal radial clearance for the shaft seal under varying operating conditions.
2Manufacturing precision
If guide elements are provided to block circumferential movement, then cover alignment is improved, but device complexity increases
Solution Approach 1:
Complex centering mechanisms are extracted and replaced with simple guide elements that merely block circumferential movement. This extraction of unnecessary complexity achieves sufficient cover alignment while minimizing device complexity.
Solution Approach 2:
The guide elements utilize the natural weight of the cover and gravity to maintain alignment, eliminating the need for complex active centering mechanisms. The cover self-aligns through the simple constraint provided by the guide elements.
3Strength
If radial shoulders are used for fastening cover to casing, then fastening strength is improved, but centering capability is not provided
Solution Approach 1:
The fastening function and centering function are merged into a single integrated design. The radial shoulders provide both the fastening strength to secure the cover to the casing and the geometric constraint necessary for precise centering, eliminating the need for separate centering mechanisms.
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 reduces radial clearance requirements, enhances operational safety, and minimizes leakage by ensuring precise centering and support of the cover, even under varying thermal conditions, while maintaining machine availability.
Implementation Method 1
the cover is advantageously equipped with a heater which, in the case of particularly cold process gases, heats the dry gas seal to a suitable operating temperature
Implementation Method 2
when there is an overpressure in the housing, the cover is pressed firmly against the casing element of the housing
Data Source
AI summary
The invention relates to a housing (CAS) having a longitudinal axis (AX) of a turbomachine (TM), the axis extending along a rotor (R), in particular to a turbocompressor housing, comprising at least one jacket part (SH) extending along the longitudinal axis (AX) and at least one end-face cover (COV), wherein said cover (COV) is surrounded by the jacket part (SH) at least with a part of the axial extension of the cover. In order to reduce the need for radial clearance, without compromising the availability or safety of the operation of the machine, the cover (COV) has radial clearance (RCL) with respect to the jacket part (SH) and at least two separate guide elements (GE) of the cover (COV) are provided on the jacket part (SH) in two different circumferential positions with respect to the longitudinal axis (AX), wherein the respective guide elements (GE) are designed such that they block a respective movement of the cover (COV) in the circumferential direction at least unidirectionally.