Compressor Port Closing Device Sealing and Needle Mark Management
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Solution Overview
Problem
Existing port closing devices for compressors, such as those disclosed in Japanese Unexamined Patent Application Publication No. 11-82858 and Japanese Utility Model Application Publication No. 58-76862, fail to provide sufficient sealing for refrigerant leakage tests due to inadequate seal areas and incomplete closure of needle marks, leading to impractical gas tightness testing.
Innovation Solution
A port closing device comprising a packing with a flat seal portion and a cap that presses the packing to ensure fluid-tight closure of compressor ports, using a bolt for fixation and a cap design that holds the packing firmly, preventing needle mark leakage during gas tightness tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a needle is pierced through the closing member for gas injection, then gas tightness testing can be performed, but the needle mark left in the closing member causes gas leakage
Solution Approach 1:
The patent converts the harmful needle mark into a beneficial feature by designing the closing member with a through-hole that accommodates the needle. The needle mark is no longer a leakage point but rather a controlled opening that maintains sealing when the needle is inserted and removed, eliminating gas leakage while preserving gas tightness testing capability
Solution Approach 2:
The closing member is segmented into distinct functional zones: a through-hole for needle insertion, a sealing portion that contacts the housing, and a protruding portion for engagement. This segmentation allows the needle mark to be isolated within the through-hole while the sealing portion maintains integrity, preventing leakage at the needle mark location
2Reliability
If a seal cap is press-fitted into the port for sealing, then gas tightness is improved, but the seal cap cannot be easily removed
Solution Approach 1:
The sealing mechanism transitions from a static press-fit design to a dynamic engagement system. The closing member features a protruding portion that engages with a corresponding groove in the housing, allowing the seal cap to be securely held during operation but easily removed by simply pulling the protruding portion, thus providing both gas tightness and ease of removal
Solution Approach 2:
An intermediary engagement mechanism (protruding portion and groove) is introduced between the seal cap and housing. This intermediary allows the seal cap to be firmly secured for sealing while providing a simple removal method, resolving the contradiction between secure sealing and easy removal without requiring complex tools or procedures
3Device complexity
If an O-ring is used as sealing member, then the sealing structure is simple, but the seal area is insufficient for preventing refrigerant leakage
Solution Approach 1:
The patent replaces the O-ring with a flexible sealing portion made of elastic material that forms a larger contact surface with the housing. This flexible sealing portion provides sufficient seal area to prevent refrigerant leakage while maintaining a relatively simple sealing structure, achieving both simplicity and reliability
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 device effectively seals compressor ports, preventing gas leakage during tests and facilitating easy removal and installation, while ensuring the integrity of the gas tightness test by using a larger seal area and elastic deformation for secure sealing.
Implementation Method 1
the needle mark left in the closing member is closed by the elastic force of the cover portion
Data Source
AI summary
There is provided a port closing device for a compressor which is fixed to a housing of the compressor by a bolt and includes a packing and a cap. The packing closes a suction port or a discharge port formed in the housing. The packing has a first end, a second end and a peripheral surface formed between the first end and the second end. The first end of the packing has a flat seal portion that is in contact with a surface of the housing surrounding the port. The cap has a holding portion that presses the peripheral surface of the packing for holding the packing, and a pressing portion that presses the second end of the packing. The pressing portion of the cap has therethrough a hole.