Seal Removal Jig Geometry for Stable Compressor Seal Detachment
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Solution Overview
Problem
The removal of seal portions from centrifugal compressors, particularly those used in large compressors handling ethylene-based gases, is challenging due to the large size of the components and the risk of fusing, making it difficult to detach the seal portions from the casing during maintenance.
Innovation Solution
A seal removal jig and method utilizing a jig body with a jig protrusion that is pushed up from below by a jack, and a jig fixing portion to detachably attach to the seal portion, allowing for easy removal by minimizing the moment generated during lifting and ensuring accurate force transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the centrifugal compressor size is increased to handle larger gas volumes, then the compression capacity is improved, but the seal portion and casing become larger and more difficult to remove during maintenance
Solution Approach 1:
A removal jig is introduced as an intermediary tool between the worker and the seal portion. The jig includes a contact portion that attaches to the seal portion and a protrusion that can be engaged by a jack, serving as a mediator to transmit removal force effectively without directly handling the large, heavy seal portion
Solution Approach 2:
The removal process is segmented into distinct functional components: the contact portion for attaching to the seal portion, the protrusion for force application, and the jack for providing lifting force. This segmentation allows each component to be optimized for its specific function, making the overall removal process more manageable
2Productivity
If ethylene-based gas is used as the working fluid, then the compression efficiency is improved, but fusing occurs between the casing and seal portion making removal more difficult
Solution Approach 1:
The removal jig acts as an intermediary that interfaces with the seal portion at a location away from the fused areas. The contact portion attaches to the end surface of the seal portion, while the protrusion transfers force from the jack without requiring direct access to the fused interface between the seal portion and casing
Solution Approach 2:
Instead of trying to pull the seal portion directly outward from the fused interface, the invention applies force from the opposite direction by pushing upward on the protrusion with a jack. This inverts the removal approach, using upward lifting force rather than lateral pulling force to overcome the fusion bonding
3Force
If a jack is used to lift the seal portion for removal, then the lifting force is improved, but the moment generated can cause unstable or inaccurate force transmission
Solution Approach 1:
The protrusion is designed with specific local geometric properties: it protrudes from the contact portion in a direction substantially perpendicular to the axial direction, creating a localized force application point. The contact portion has a specific shape configured to engage the protrusion, ensuring that the lifting force is transmitted accurately without generating excessive moment
Solution Approach 2:
The protrusion creates an asymmetric force application geometry relative to the seal portion's center. By positioning the protrusion at a specific offset distance (0.01 to 0.1 times the seal portion outer diameter), the design intentionally creates a controlled moment arm that prevents the seal portion from rotating during removal while maintaining stable force transmission
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 seal removal jig enables efficient and stable detachment of seal portions from the casing, reducing the effort required for maintenance and preventing damage during removal.
Implementation Method 1
a jig protrusion protruding outward in the radial direction with respect to the jig contact portion and configured to be pushed up from below in the vertical direction by a jack
Data Source
AI summary
A seal removal jig is used for removing a seal portion from a casing of a rotary machine. The seal removal jig includes a jig body pushed up from below in a vertical direction by a jack, and a jig fixing portion that detachably fixes the jig body to an end surface of the seal portion. The jig body includes a jig contact portion that is contactable with an end surface of an upper half seal portion or a lower half seal portion in a circumferential direction about an axis of the rotary machine; and a jig protrusion protruding outward in a radial direction with respect to the jig contact portion and pushed up from below in the vertical direction by the jack. The ratio of a first distance to an outside diameter of the upper half seal portion or the lower half seal portion is 0.01 or more and 0.1 or less.